uu.seUppsala universitets publikasjoner
Endre søk
Begrens søket
1234567 1 - 50 of 12917
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    Aaboen, Lise
    et al.
    Norwegian University of Science and Technology .
    La Rocca, Antonella
    BI Norwegian Business School.
    Lind, Frida
    Chalmers University of Technology.
    Perna, Andrea
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Industriell teknik. Universita' Politecnica delle Marche.
    Shih, Tommy
    Starting up in Business Networks: Why relationships matter in entrepreneurship2016 (oppl. 1st)Bok (Fagfellevurdert)
  • 2.
    Aakash, förnamn
    et al.
    Department of Electronics and Communication Engg., Birla Institute of Technology.
    Nordblad, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Mohan, Rajendra
    Department of Physics, National Institute of Technology Patna.
    Mukherjee, Samrat
    Department of Physics, National Institute of Technology Patna.
    Structural, magnetic and hyperfine characterizations of nanocrystalline Zn-Cd doped nickel ferrites2017Inngår i: Journal of Magnetism and Magnetic Materials, ISSN 0304-8853, E-ISSN 1873-4766, Vol. 441, s. 710-717Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In our present work, we have synthesized a series of Cd-Zn doped nickel ferrite ((Cd-0.5 Zn-x(x)) Ni0(.5)Fe(2)O(4); x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) through standard chemical co-precipitation method to study the influence of diamagnetic ions (Cd, Zn) on the magnetic properties of ferrites. XRD and Raman spectroscopy were employed for the structural characterizations. The refinement of the X-ray diffractogram data augmented by the Williamson-Hall plots showed the presence of Cd2+ vacancies and a strained crystal structure. The vibrational spectroscopy indicated the presence of lower space-group symmetry and a distorted crystal structure. Magnetic measurements showed the samples possessed low magnetic anisotropy along with a canted spin structure. The Mossbauer measurements confirmed the cation distribution and gave evidence of super transferred hyperfine interactions arising due to canted spin structure of the system.

  • 3.
    Abad, Manuel David
    et al.
    Instituto de Ciencia de Materiales de Sevilla, ICMS (CSIC-US), Spanien.
    Sanjines, Rosendo
    Ecole Polytechnique Federale de Lausanne, IPMC-SB, Lausanne, Schweiz.
    Endrino, Jose Luis
    Instituto de Ciencia de Materiales de Madrid, ICMM (CSIC), Spanien.
    Gago, Raul
    Instituto de Ciencia de Materiales de Madrid, ICMM (CSIC), Spanien.
    Andersson, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Sanchez-Lopez, Juan Carlos
    Instituto de Ciencia de Materiales de Sevilla, ICMS (CSIC-US), Spanien.
    Identification of Ternary Phases in TiBC/a-C Nanocomposite Thin Films: Influence on the Electrical and Optical Properties2011Inngår i: Plasma Processes and Polymers, ISSN 1612-8850, E-ISSN 1612-8869, Vol. 8, nr 7, s. 579-588Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The local structure of TiBC and amorphous carbon (a-C) nanocomposite films (TiBC/a-C) was correlated with their optical and electrical properties. TiBC/a-C films with increasing C content were deposited by magnetron co-sputtering from TiC:TiB(2) (60: 40) and graphite targets. Chemical composition is determined by electron energy-loss spectroscopy. Grazing incidence X-ray diffraction reveals that the microstructure of the films is amorphous with small nanocrystallites emerging by increasing the C content that could be attributed to the formation of ternary (TiB(x)C(y)) or mixed binary (TiB(2) and TiC) phases. Further information was then obtained by studying the chemical bonding by measuring the near-edge fine structure (NES) by electron energy-loss (B K-, C K-, and Ti L-edges) and X-ray absorption (B K-and Ti L-edges) spectroscopies. The NES analysis indicates the formation of a nanocrystalline ternary TiB(x)C(y) compound concomitant with the segregation of an a-C phase as the carbon content is increased. The optical properties were studied by spectroscopic ellipsometry and the electrical resistivity was measured by the Van der Pauw method between 20 and 300 K. The films continuously lose their metallic character in terms of optical constants and resistivity with increasing carbon content. Theoretical fitting of the electrical properties using the grain-boundary scattering model supported the formation of a nanocomposite structure based on a ternary TiB(x)C(y) phase embedded in a matrix of a-C. The electron transport properties are mainly limited by the high density of point defects, grain size, and transmission probability.

  • 4.
    Abdallah, Ali
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Det smarta hemmet – Energianvändarens framtid: En studie om smarta hem och vilka möjligheter Jämtkraft har att satsa på dessa2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Energianvändningen i Sverige är relativt stort med avseende på befolkningsmängden. Det beror givetvis mycket på behovet av uppvärmning under större delen av året som det kalla klimatet leder till men även på det kontinuerliga behovet av energi i det vardagliga livet. Den stora energianvändningen medför dock stora belastningar på både klimat och miljö. I dagsläget finns det flera uppsatta mål som är riktade till att minska energiintensiteten i landet samt energianvändningen i bostäder och lokaler. Således är energieffektivisering ett viktigt medel för att minska klimat- och miljöbelastningen. Många energianvändare utför olika vardagliga rutiner som bidrar till energieffektivisering som att bland annat släcka lampor, stänga av elektriska apparater när de inte används och inte använda disk- eller tvättmaskinen om den är halvfull. De ovannämnda åtgärderna är dock inte tillräckliga. Det krävs mer och därför är smarta hem en viktig lösning. Smarta hem är ett komplext system som täcker olika aspekter i hemmet men anses vara ett effektivt medel för energieffektivisering. Hur energianvändningen i bostäder utvecklas i framtiden kommer med stor sannolikhet bero på smarta hem och smarta produkter.

    Syftet med detta examensarbete är att undersöka hur man skulle kunna utveckla eller kombinera energismarta produkter på bästa möjliga sätt. Utifrån en enkätundersökning riktad mot energianvändare och intervjuer med energianvändare och aktörer på den smarta hemmarknaden har energikonsumenternas behov och beteende analyserats och en marknadsanalys av de produkter som finns på marknaden idag utförts.

    Denna studie har visat att energianvändarna allmänt inte är så insatta i energianvändningen hemma trots att många påstår sig vara engagerade i energieffektivisering. Energianvändarna visade samtidigt på bristande kunskap om smarta hem och energismarta produkter, vilket kan bero på att smarta hemmarknaden fortfarande är ny i Sverige och de flesta aktörer har ännu inte lyckats marknadsföra sig och sina produkter. Det kan även bero på andra faktorer som brist på intresse hos energianvändarna att energieffektivisera som i sin tur kan bero på det låga elpriset i Sverige. De ovannämnda faktorerna kan göra att utvecklingen av smarta hem i Sverige tar längre tid än förväntat. Energianvändarna visade sig prioritera främst kostnader, och utför ofta energieffektiviserings åtgärder för att spara pengar snarare än att bidra till klimatet.

    Studien visade att ett smart hem bör innehålla produkter som bidrar till komfort, säkerhet och ekonomiska besparingar. Produkter som prioriteras hos energianvändarna och efterfrågas mest på marknaden är smarta brandvarningssystem, smarta dörrlås, smarta energidisplayer, smarta inbrottslarm samt smarta system för styrning av värme och belysning. Samtliga ovannämnda produkter erbjuds på marknaden idag, även om många av dessa är i utvecklingsfasen. Elföretaget Jämtkraft bör ta hänsyn till resultaten i detta examensarbete inför framtida satsningar på smarta hem.

  • 5.
    Abdallah, Ali
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Industriell teknik.
    The perception of Nuclear powerin Sweden: How engineering students view it2017Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Nuclear power has been an important part of the electricity generatingin Sweden in almost half a century. However, the use of nuclear powerraises many complex issues such as economy, accident risks, andradioactive waste management and storage. Nuclear power has thereforebeen debated intensively in Sweden as in many other countries since the1970s. Several countries have changed their nuclear policy and starteddecommissioning programs following the nuclear accident in Fukushimaback in 2011. Citizens' support for nuclear power has declined worldwidein last few years, including in Sweden. This study aims to investigatethe perception of nuclear power among engineering students and showsthat the majority of engineering students, who generally are positivetowards technology, have been affected by their surrounding and areagainst nuclear power. Engineering students in general, both supportersand opponents of nuclear power, agree that Sweden should gradually phaseout nuclear power and replace it by renewable energy sources.

  • 6.
    Abdi-Jalebi, Mojtaba
    et al.
    Univ Cambridge, Dept Phys, Cavendish Lab, JJ Thomson Ave, Cambridge, England.
    Pazoki, Meysam
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Philippe, Bertrand
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Dar, M. Ibrahim
    Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photon & Interfaces, Lausanne, Switzerland.
    Alsari, Mejd
    Univ Cambridge, Dept Phys, Cavendish Lab, JJ Thomson Ave, Cambridge, England.
    Sadhanala, Aditya
    Univ Cambridge, Dept Phys, Cavendish Lab, JJ Thomson Ave, Cambridge, England.
    Diyitini, Giorgio
    Univ Cambridge, Dept Mat Sci & Met, Charles Babbage Rd, Cambridge, England.
    Imani, Roghayeh
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Lilliu, Samuele
    Univ Sheffield, Dept Phys & Astron, Sheffield, S Yorkshire, England; UAE Ctr Crystallog, Dubai, U Arab Emirates.
    Kullgren, Jolla
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Rensmo, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Gratzel, Michael
    Ecole Polytech Fed Lausanne, Inst Chem Sci & Engn, Lab Photon & Interfaces, Lausanne, Switzerland.
    Friend, Richard H.
    Univ Cambridge, Dept Phys, Cavendish Lab, JJ Thomson Ave, Cambridge, England.
    Dedoping of Lead Halide Perovskites Incorporating Monovalent Cations2018Inngår i: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, nr 7, s. 7301-7311Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report significant improvements in the optoelectronic properties of lead halide perovskites with the addition of monovalent ions with ionic radii close to Pb2+. We investigate the chemical distribution and electronic structure of solution processed CH3NH3PbI3 perovskite structures containing Na+, Cu+, and Ag+, which are lower valence metal ions than Pb2+ but have similar ionic radii. Synchrotron X-ray diffraction reveals a pronounced shift in the main perovskite peaks for the monovalent cation-based films, suggesting incorporation of these cations into the perovskite lattice as well as a preferential crystal growth in Ag+ containing perovskite structures. Furthermore, the synchrotron X-ray photoelectron measurements show a significant change in the valence band position for Cu- and Ag-doped films, although the perovskite bandgap remains the same, indicating a shift in the Fermi level position toward the middle of the bandgap. Such a shift infers that incorporation of these monovalent cations dedope the n-type perovskite films when formed without added cations. This dedoping effect leads to cleaner bandgaps as reflected by the lower energetic disorder in the monovalent cation-doped perovskite thin films as compared to pristine films. We also find that in contrast to Ag+ and Cu+, Na+ locates mainly at the grain boundaries and surfaces. Our theoretical calculations confirm the observed shifts in X-ray diffraction peaks and Fermi level as well as absence of intrabandgap states upon energetically favorable doping of perovskite lattice by the monovalent cations. We also model a significant change in the local structure, chemical bonding of metal-halide, and the electronic structure in the doped perovskites. In summary, our work highlights the local chemistry and influence of monovalent cation dopants on crystallization and the electronic structure in the doped perovskite thin films.

  • 7.
    Abdu, Yassir
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper. Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysik III. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Ericsson, Tore
    Fysiska institutionen. Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysik III. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nordblad, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Fysiska sektionen, Institutionen för fysik och materialvetenskap, Fysik III. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Field-induced local magnetic moments in γ (FCC) Fe-Ni anti –Invar alloys2004Inngår i: J. Mag. Mag. Mater, Vol. 280, s. 243-250Artikkel i tidsskrift (Fagfellevurdert)
  • 8.
    Abdulahi Mohamed, Abdirahman
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Aksel, Wännström
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Quality Control of Light Emitting Diodes: Using power factor, harmonic distortion and light to power ratios2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This study addresses quality control for Light Emitting Diodes (LED) according to fouraspects, the power factor of LED lamps, their harmonics and total harmonic distortion (THD), the luminosity for total power to radiated power ratio. It focuses on four brands and six different LED lamps, and concludes that IKEA's LED lamps pertain as the quality lamp, with a power factor over 0.9, THD less than 4% and a power to radiated light of over 4%. 

  • 9. Abegunawardana, Sidath
    et al.
    Bodhika, J A P
    Abewardhana, Ruwan
    Fernando, Mahendra
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Sound Source Localization of Lightning Discharges2018Konferansepaper (Fagfellevurdert)
  • 10. Abegunawardana, Sidath
    et al.
    Bodhika, J A P
    Nanayakkara, Sankha
    Sonnadara, Upul
    Fernando, Mahendra
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Audible Frequency Analysis of Ground Flashes2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Thunder signatures categorized into three types based on peak pressure and variation in fundamental frequency, have been studied by using acoustic spectrum of thunder. S-transformation has been used to estimate the dominant frequency variation around the peak pressure. The mean fundamental frequencies of type 3 ground and cloud flashes are 160 Hz and 98 Hz respectively. The mean frequencies of type 2 ground and cloud flashes are 108 Hz and 82 Hz respectively.

  • 11.
    Abele, P
    et al.
    tyskland.
    Öjefors, E
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Signals and systems.
    Schad, K B
    tyskland.
    and Schumacher H, Sonmez, E, Trasser A, Konle J
    tyskland.
    Wafer level integration of a 24 GHz differential SiGe-MMIC oscillator with a patch antenna using BCB as a dielectric layer2003Konferansepaper (Fagfellevurdert)
  • 12.
    Abermann, S.
    et al.
    Institute of Solid State Electronics, Vienna University of Technology.
    Efavi, J. K.
    Sjöblom, Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Lemme, M. C.
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bertagnolli, E.
    Institute of Solid State Electronics, Vienna University of Technology.
    Impact of Al-, Ni-, TiN-, and Mo-metal gates on MOCVD-grown HfO2 and ZrO2 high-k dielectrics2007Inngår i: Microelectronics and reliability, ISSN 0026-2714, E-ISSN 1872-941X, Vol. 47, nr 4-5, s. 536-539Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work we compare the impacts of nickel (Ni), titanium-nitride (TiN), molybdenum (Mo), and aluminium (Al), gates on MOS capacitors incorporating HfO2- or ZrO2-dielectrics. The primary focus lies on interface trapping, oxide charging, and thermodynamical stability during different annealing steps of these gate stacks. Whereas Ni, Mo, and especially TiN are investigated as most promising candidates for future CMOS devices, Al acted as reference gate material to benchmark the parameters. Post-metallization annealing of both, TiN- and Mo-stacks, resulted in very promising electrical characteristics. However, gate stacks annealed at temperatures of 800 °C or 950 °C show thermodynamic instability and related undesirable high leakage currents.

  • 13.
    Abermann, S.
    et al.
    Institute for Solid State Electronics, Vienna University of Technology.
    Efavi, J. K.
    Advanced Microelectronic Center, Aachen.
    Sjöblom, Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Lemme, M. C.
    Advanced Microelectronic Center, Aachen.
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bertagnolli, E.
    Institute for Solid State Electronics, Vienna University of Technology.
    Processing and evaluation of metal gate/high-k/Si capacitors incorporating Al, Ni, TiN, and Mo as metal gate, and ZrO2 and HfO2 as high-k dielectric2007Inngår i: Microelectronic Engineering, ISSN 0167-9317, E-ISSN 1873-5568, Vol. 84, nr 5-8, s. 1635-1638Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We evaluate various metal gate/high-k/Si capacitors by their resulting electrical characteristics. Therefore, we process MOS gate stacks incorporating aluminium (Al), nickel (Ni), titanium-nitride (TiN), and molybdenum (Mo) as the gate material, and metal organic chemical vapour deposited (MOCVD) ZrO2 and HfO2 as the gate dielectric, respectively. The influence of the processing sequence - especially of the thermal annealing treatment - on the electrical characteristics of the various gate stacks is being investigated. Whereas post metallization annealing in forming gas atmosphere improves capacitance-voltage behaviour (due to reduced interface-, and oxide charge density), current-voltage characteristics degrade due to a higher leakage current after thermal treatment at higher temperatures. The Flatband-voltage values for the TiN-, Mo-, and Ni-capacitors indicate mid-gap pinning of the metal gates, however, Ni seems to be thermally unstable on ZrO2, at least within the process scheme we applied.

  • 14. Abermann, S
    et al.
    Efavi, J
    Sjöblom, Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Lemm, M
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bertagnolli, E
    Impact of Al-, Ni-, TiN-, and Mo metal gates on MOCVD-grown HfO2 and ZrO2 high-K dielectrics2006Konferansepaper (Fagfellevurdert)
  • 15. Abermann, S.
    et al.
    Efavi, J.
    Sjöblom, Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Lemme, Max
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bertagnolli, E.
    Processing and evaluation of metal gate/high-k/Si capacitors incorporating Al, Ni, TiN, and Mo as metal gate, and ZrO2 and HfO2 as high-k dielectric2006Inngår i: Presented at Int. Conf. on Micro- and Nano-Engineering, 2006Konferansepaper (Annet vitenskapelig)
  • 16. Abermann, Stephan
    et al.
    Sjöblom, Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Efavi, Johnson
    Lemme, Max
    Olsson, Jörgen
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Bertagnolli, Emmerich
    Comparative Study On The Impact Of TiN and Mo Metal Gates ON MOCVD-Grown HfO2 and ZrO2 High-k Dielectrics For CMOS Technology2006Inngår i: Proceedings of 28th International Conference on the Physics of Semiconductors (ICPS) / [ed] Wolfgang Jantsch, Friedrich Schäffler, 2006Konferansepaper (Fagfellevurdert)
  • 17. Abewardhana, Ruwan
    et al.
    Abegunawardana, Sidath
    Fernando, Mahendra
    Sonnadara, Upul
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Lightning Localization Based on VHF Broadband Interferometer Developed in Sri Lanka2018Konferansepaper (Fagfellevurdert)
  • 18.
    Aboud, Mathilde
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Industriell teknik.
    Corporate Sustainability as a Foresight Activity: Can Corporate Sustainability help companies survive in an increasingly competitive environment?2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In many corporations, sustainability has become an important activity to focuson, with the aim of preparing corporations for the future. Foresight, a newerfield, is increasingly becoming an important activity of corporations, with thepurpose of surviving long-term. These motives make companies’ involvement with corporate sustainability and with corporate foresight fundamental. However, because foresight is a recent field, it implies processes that are less mastered by professionals than sustainability.

    Since the motives of corporate sustainability and corporate foresight are similar, the purpose of this thesis is therefore to understand if corporate sustainability can contribute to corporate foresight implementation. Specifically, the purpose of this thesis is to identify which corporate sustainability (CS) activities can be integrated to which corporate foresight (CF) activities, to facilitate and foster foresight.

    Consequently, the contributions of the research consist in extending the knowledge about sustainability as a foresight activity and in proposing suggestions to incorporate sustainability to foresight activities.

    This study reviews several CS frameworks and several CF frameworks, provides a deeper understanding of the underlying processes needed for the implementation of CS and CF, and identifies the similarities. The study specifically builds on the Maturity Model of Corporate Foresight from the book Corporate Foresight – Towards a Maturity Model for the Future Orientation of a Firm from Rohrbeck (2010). Based on the theoretical findings, qualitative interviews of sustainability professionals are carried out. Those interviews are meant to test the theoretical findings.

    The research provides knowledge on the management of corporate foresightby providing insights on foresight practices that benefit from incorporating sustainability practices. The conclusion of the paper consists in a model thatpresents explicit ways in which corporate sustainability contributes tocorporate foresight. In fact, it is shown that corporate sustainability fosters strong internal and external networks and creates a corporate culture favourable to change. Internal and external networks facilitate cross-functional collaboration and communication; and employees favourable to change are more open to new ideas; both being key for foresight implementation. Thus, Corporate Sustainability supports Corporate Foresight because it sets up a favourable corporate culture, and because it paves the way for appropriate work processes (internal and external collaboration for instance).

  • 19.
    Aboulfadl, Hisham
    et al.
    Chalmers Univ Technol, Dept Phys, S-41296 Gothenburg, Sweden.
    Keller, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Larsen, Jes K
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Thuvander, Mattias
    Chalmers Univ Technol, Dept Phys, S-41296 Gothenburg, Sweden.
    Riekehr, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Edoff, Marika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Platzer Björkman, Charlotte
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Microstructural Characterization of Sulfurization Effects in Cu(In,Ga)Se-2 Thin Film Solar Cells2019Inngår i: Microscopy and Microanalysis, ISSN 1431-9276, E-ISSN 1435-8115, Vol. 25, nr 2, s. 532-538Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Surface sulfurization of Cu(In,Ga)Se-2 (CIGSe) absorbers is a commonly applied technique to improve the conversion efficiency of the corresponding solar cells, via increasing the bandgap towards the heterojunction. However, the resulting device performance is understood to be highly dependent on the thermodynamic stability of the chalcogenide structure at the upper region of the absorber. The present investigation provides a high-resolution chemical analysis, using energy dispersive X-ray spectrometry and laser-pulsed atom probe tomography, to determine the sulfur incorporation and chemical re-distribution in the absorber material. The post-sulfurization treatment was performed by exposing the CIGSe surface to elemental sulfur vapor for 20 min at 500 degrees C. Two distinct sulfur-rich phases were found at the surface of the absorber exhibiting a layered structure showing In-rich and Ga-rich zones, respectively. Furthermore, sulfur atoms were found to segregate at the absorber grain boundaries showing concentrations up to similar to 7 at% with traces of diffusion outwards into the grain interior.

  • 20.
    Abou-Ras, Daniel
    et al.
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Hahn Meitner Pl 1, D-14109 Berlin, Germany..
    Wagner, Sigurd
    Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA..
    Stanbery, Bill J.
    Siva Power, 5102 Calle Sol, Santa Clara, CA 95054 USA..
    Schock, Hans-Werner
    Helmholtz Zentrum Berlin Mat & Energie GmbH, Hahn Meitner Pl 1, D-14109 Berlin, Germany..
    Scheer, Roland
    Martin Luther Univ Halle Wittenberg, Inst Phys, Photovolta Grp, D-06120 Halle, Saale, Germany..
    Stolt, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik. Solibro Res AB, Sweden.
    Siebentritt, Susanne
    Univ Luxembourg, Phys & Mat Sci Res Unit, Lab Photovolta, Belvaux, Luxembourg..
    Lincot, Daniel
    CNRS EDF Chim Paristech PSL, Inst Photovolta Ile France IPVF, IRDEP, 6 Quai Watier, F-78401 Chatou, France..
    Eberspacher, Chris
    Solopower Syst Inc, Corp & Mfg Headquarters, 6308 North Marine Dr, Portland, OR 97203 USA..
    Kushiya, Katsumi
    Solar Frontier KK, 123-1 Shimo Kawairi, Atsugi, Kanagawa, Japan..
    Tiwari, Ayodhya N.
    Empa Swiss Fed Labs Mat Sci & Technol, Lab Thin Films & Photovolta, Ueberlandstr 129, CH-8600 Dubendorf, Switzerland..
    Innovation highway: Breakthrough milestones and key developments in chalcopyrite photovoltaics from a retrospective viewpoint2017Inngår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 633, s. 2-12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present contribution is a summary of an event that was organized as a special evening session in Symposium V "Chalcogenide Thin-Film Solar Cells" at the E-MRS 2016 Spring Meeting, Lille, France. The presentations in this session were given by the coauthors of this paper. These authors present retrospectives of key developments in the field of Cu(In,Ga)(S,Se)(2) solar cells as they themselves had witnessed in their laboratories or companies. Also, anecdotes are brought up, which captured interesting circumstances in that evolutionary phase of the field. Because the focus was on historical perspectives rather than a comprehensive review of the field, recent developments intentionally were not addressed.

  • 21.
    Abrahamsson, Camilla
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Dubois, Philip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Englund, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    En jämförande studie av säljklimatet inom företagshälsovårdsmarknaden i Sverige2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Denna studie ämnar till att beskriva hur startup-bolag kan identifiera den försäljningsstrategi som lämpar sig bäst inom företagshälsovårdsmarknaden i Sverige.  Dessa utmaningar har sedan lyfts till en generell nivå där syftet är att identifiera företags försäljningsstrategier i relation till olika mikromarknader. Detta har utförts genom en fallstudie av företaget Onelab, som med sin tjänst är ett av de första företagen på den svenska marknaden att erbjuda kunder personliga hälsoprofiler, som ett komplement till företagshälsovårdens tjänster. Den empiriska studien bygger på nio semistrukturerade intervjuer hos strategiskt utvalda företag inom teknik- och konsultbranscher, med högpresterande och välutbildade medarbetare. Samtliga respondenter var HR-personer, som i någon form ansvarade för företagets företagshälsovård och inköp av företagshälsovårdstjänster. Uppsatsen mynnar ut i en dynamisk modell som både startup-företag och etablerade företag kan nyttja för att anpassa sin försäljningsstrategi beroende på kunders olika komplexitet och organisationsstorlek. Uppsatsen ger direkta råd till referensföretaget Onelab däribland rekommendationen att inte överge det marknadssegment som de ursprungligen riktat sig mot, konsumentmarknaden (B2C) samt att de bör använda sig av en informell säljprocess där säljaren, med guidning av cheferna, lämnas utrymme att själv driva processen som han eller hon finner bäst lämpad för situationen. Då denna studie är resursmässigt begränsad och empiriska fynd enbart insamlade från nio respondenter uppmanar vi till fortsatta studier. Detta främst för att generera en fördjupad kunskap gällande sambandet mellan försäljningsstrategier och framgångsrika startup-bolag, men även för att kunna dra generella slutsatser, verifiera den dynamiska modellen som genererats samt undersöka om den även kan tillämpas inom fler branscher.

  • 22.
    Abrahamsson, Caroline
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    Waltersson, Johanna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    FLEXIBLA BYGGNADER: Utformning av en förskola med en möjlig verksamhetsändring för framtida behov2014Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    För att uppnå ett långsiktigt hållbart samhälle ställs idag höga krav på en miljömässigt och ekonomiskt hållbar utveckling. Samhällets expansion i form av nybyggnation är en stor del i detta. Genom att planera och bygga mer långsiktigt hållbara byggnader så kan dessa krav uppfyllas. Att skapa flexibla byggnader, som kan anpassas efter samhällets framtida behov, leder till en effektivisering av lokalutnyttjandet och genererar mer långsiktigt hållbara byggnader. I Sverige är kommunerna landets största byggherrar och de har därför ett stort ansvar att förse samhället med fastigheter och då framförallt offentliga lokaler. En typ av offentliga lokaler där behovet av flexibla byggnader är stort är förskolor, i och med att det är svårt att förutse hur det framtida behovet av förskolor kommer att se ut då storleken på barnkullarna varierar.

    Detta examensarbete inom högskoleingenjörsprogrammet i byggteknik har utförts under tio veckor på Tengbom Arkitekter i Uppsala. Arbetet behandlar ämnet flexibilitet i byggnader och innefattar ett förslag på utformningen av en flexibel byggnad i form av en förskola som i framtiden kan konverteras till ett äldreboende.

  • 23.
    Abrahamsson, Curt Johan David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Pérez-Loya, Jesús José
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Fregelius, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Evestedt, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bladh, Johan
    Lundin, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Magnetic thrust bearing for a 10 MW hydropower generator with a Kaplan turbine2018Konferansepaper (Fagfellevurdert)
  • 24.
    Abrahamsson, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Kinetic Energy Storage and Magnetic Bearings: for Vehicular Applications2014Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    One of the main challenges in order to make electric cars competitive with gas-powered cars is in the improvement of the electric power system. Although many of the energy sources currently used in electric vehicles have sufficientlyhigh specific energy, their applicability is limited due to low specific power. It would therefore be advantageous to create a driveline with the main energy storage separated from a smaller energy buffer, designed to have high power capabilities and to withstand frequent and deep discharge cycles. It has been found that rotating kinetic energy storage in flywheels is very well suited for this type of application.

    A composite shell, comprising an inner part made of glassfiber and an outer part made of carbonfiber, was analyzed analytically and numerically, designed, and constructed. The shell was fitted onto a metallic rotor using shrinkfitting. The cost of the shell, and the complexity of assembly, was reduced by winding the glass- and carbonfiber consecutively on a mandrel, and curing the complete assembly simultaneously. Thereby, the shell obtained an internal segmentation, without the need for fitting several concentric parts onto each other. The radial stress inside the composite shell was kept compressive thanks to a novel approach of using the permanent magnets of the integrated electric machine to provide radial mechanical load during rotation.

    Two thrust bearing units (one upper and one lower) comprising one segmented unit with the permanent magnets in a cylindrical Halbach configuration and one non-segmented unit in a up/down configuration were optimized, constructed and tested. Each thrust bearing unit generated 1040 N of repelling force, and a positive axial stiffness of 169 N/mm at the nominal airgap of 5 mm. 

    Two radial active magnetic bearings (one upper and one lower) were optimized, constructed and tested. By parameterizing the shape of the actuators, a numerical optimization of force over resistive loss from the bias currentcould be performed. The optimized shape of the electromagnets was produced by watercutting sheets of laminated steel. A maximum current stiffness of120 N/A at a bias current of 1.5 A was achieved.

    Delarbeid
    1. Prototype of electric driveline with magnetically levitated double wound motor
    Åpne denne publikasjonen i ny fane eller vindu >>Prototype of electric driveline with magnetically levitated double wound motor
    Vise andre…
    2010 (engelsk)Inngår i: Electrical Machines (ICEM), 2010 XIX International Conference on, 2010Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    This paper presents the ongoing work of constructing a complete driveline for an electric road vehicle, using a flywheel as auxiliary energy storage. The flywheel energy storage system (FESS) is connected in series between the main energy storage (batteries) and the wheel motor of the vehicle, allowing the batteries to deliver power to the system in an optimized way, while at the same time making efficient use of regenerative braking. A double wound permanent magnet electric machine is used to electrically separate the two sides. In order to minimize losses, the machine has a double rotor configuration and is suspended with magnetic bearings. A bench test set-up is being constructed to investigate the properties of this system in detail. This set-up will achieve a level of power and energy close to that of a full scale system. This will allow measurements of complete drive cycles to be performed, improving the understanding of the constituting components and optimization of the complete system.

    Emneord
    electric drives, flywheels, magnetic bearings, permanent magnet machines, regenerative braking, road vehicles, auxiliary energy storage, double rotor configuration, double wound permanent magnet electric machine, electric driveline, electric road vehicle, flywheel energy storage system, magnetically levitated double wound motor, wheel motor
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-140370 (URN)
    Konferanse
    International Conference on Electrical Machines, ICEM
    Tilgjengelig fra: 2011-01-05 Laget: 2011-01-05 Sist oppdatert: 2016-04-18bibliografisk kontrollert
    2. Magnetic bearings in kinetic energy storage systems for vehicular applications
    Åpne denne publikasjonen i ny fane eller vindu >>Magnetic bearings in kinetic energy storage systems for vehicular applications
    2011 (engelsk)Inngår i: Journal of Electrical Systems, ISSN 1112-5209, Vol. 7, nr 2, s. 225-236Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The rotating Kinetic Energy Storage System (KESS) is suitable as temporary energy storage in electric vehicles due to its insensitivity to the number of charge-discharge cycles and its relatively high specific energy. The size and weight of the KESS for a given amount of stored energy are minimized by decreasing the moment of inertia of the rotor and increasing its speed. A small and fast rotor has the additional benefit of reducing the induced gyroscopic moments as the vehicle turns. The very high resulting rotational speed makes the magnetic bearing an essential component of the system, with the Active Magnetic Bearing (AMB) being the most common implementation. The complexity and cost of an AMB can be reduced by integration with the electric machine, resulting in a bearingless and sensorless electric machine. This review article describes the usage of magnetic bearings for FESS in vehicular applications.

    Emneord
    Magnetic bearing, FESS, flywheel, energy storage, electric vehicle
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-165038 (URN)
    Tilgjengelig fra: 2012-01-02 Laget: 2012-01-02 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    3. Prototype of Kinetic Energy Storage System for Electrified Utility Vehicles in Urban Traffic
    Åpne denne publikasjonen i ny fane eller vindu >>Prototype of Kinetic Energy Storage System for Electrified Utility Vehicles in Urban Traffic
    2012 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    Arlington, Virginia, USA: , 2012
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-190197 (URN)
    Konferanse
    13th International Symposium on Magnetic Bearings
    Tilgjengelig fra: 2013-01-07 Laget: 2013-01-07 Sist oppdatert: 2017-04-06
    4. On the Efficiency of a Two-Power-Level Flywheel-Based All-Electric Driveline
    Åpne denne publikasjonen i ny fane eller vindu >>On the Efficiency of a Two-Power-Level Flywheel-Based All-Electric Driveline
    Vise andre…
    2012 (engelsk)Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 5, nr 8, s. 2794-2817Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This paper presents experimental results on an innovative electric driveline employing a kinetic energy storage device as energy buffer. A conceptual division of losses in the system was created, separating the complete system into three parts according to their function. This conceptualization of the system yielded a meaningful definition of the concept of efficiency. Additionally, a thorough theoretical framework for the prediction of losses associated with energy storage and transfer in the system was developed. A large number of spin-down tests at varying pressure levels were performed. A separation of the measured data into the different physical processes responsible for power loss was achieved from the corresponding dependence on rotational velocity. This comparison yielded an estimate of the perpendicular resistivity of the stranded copper conductor of 2.5 x 10(-8) +/- 3.5 x 10(-9). Further, power and energy were measured system-wide during operation, and an analysis of the losses was performed. The analytical solution was able to reproduce the measured distribution of losses in the system to an accuracy of 4.7% (95% CI). It was found that the losses attributed to the function of kinetic energy storage in the system amounted to between 45% and 65%, depending on usage.

    Emneord
    kinetic energy storage, flywheel, electric machine, driveline, electric vehicle, losses
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-182543 (URN)10.3390/en5082794 (DOI)000308241500011 ()
    Tilgjengelig fra: 2012-10-11 Laget: 2012-10-11 Sist oppdatert: 2017-12-07bibliografisk kontrollert
    5. A Fully Levitated Cone-Shaped Lorentz-Type Self-Bearing Machine With Skewed Windings
    Åpne denne publikasjonen i ny fane eller vindu >>A Fully Levitated Cone-Shaped Lorentz-Type Self-Bearing Machine With Skewed Windings
    2014 (engelsk)Inngår i: IEEE transactions on magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 50, nr 9, artikkel-id 8101809Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Brushless dc coreless electric machines with double-rotor and single-stator configuration have very low losses, since the return path of the magnetic flux rotates with the permanent magnets. The eddy-current loss in the stator is additionally very small due to the lack of iron, making it ideal for kinetic energy storage. This paper presents a design for self-bearing rotor suspension, achieved by placing the stator windings skewed on a conical surface. A mathematical analysis of the force from a skewed winding confined to the surface of a cone was found. The parametric analytical expressions of the magnitude and direction of force and torque were verified by finite-element method simulations for one specific geometry. A dynamic model using proportional-integral-differential control was implemented in MATLAB/Simulink, and the currents needed for the self-bearing effect were found by solving an underdetermined system of linear equations. External forces, calculated from acceleration measurements from a bus in urban traffic, were added to simulate the dynamic environment of an electrical vehicle.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-212105 (URN)10.1109/TMAG.2014.2321104 (DOI)000343036900019 ()
    Tilgjengelig fra: 2013-12-05 Laget: 2013-12-05 Sist oppdatert: 2017-12-06bibliografisk kontrollert
    6. Passive Axial Thrust Bearing for a Flywheel Energy Storage System
    Åpne denne publikasjonen i ny fane eller vindu >>Passive Axial Thrust Bearing for a Flywheel Energy Storage System
    Vise andre…
    2013 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-212104 (URN)
    Konferanse
    The 1st Brazilian Workshop on Magnetic Bearings
    Tilgjengelig fra: 2013-12-05 Laget: 2013-12-05 Sist oppdatert: 2017-10-24
    7. High-Speed Kinetic Energy Buffer: Optimization of Composite Shell and Magnetic Bearings
    Åpne denne publikasjonen i ny fane eller vindu >>High-Speed Kinetic Energy Buffer: Optimization of Composite Shell and Magnetic Bearings
    2014 (engelsk)Inngår i: IEEE transactions on industrial electronics (1982. Print), ISSN 0278-0046, E-ISSN 1557-9948, Vol. 61, nr 6, s. 3012-3021Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This paper presents the design and optimization of a high-speed (30 000 r/min) kinetic energy storage system. The purpose of the device is to function as an energy buffer storing up to 867 Wh, primarily for utility vehicles in urban traffic. The rotor comprises a solid composite shell of carbon and glass fibers in an epoxy matrix, constructed in one curing. The shell is optimized using a combined analytical and numerical approach. The radial stress in the shell is kept compressive by integrating the electric machine, thereby avoiding delamination. Radial centering is achieved through eight active electromagnetic actuators. The actuator geometry is optimized using a direct coupling between SolidWorks, Comsol, and Matlab for maximum force over resistive loss for a given current density. The optimization results in a system with 300% higher current stiffness than the reference geometry with constant flux area, at the expense of 33% higher power loss. The actuators are driven by semipassive H bridges and controlled by an FPGA. Current control at 20 kHz with a noise of less than 5 mA (95% CI) is achieved, allowing position control at 4 kHz to be implemented.

    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-212101 (URN)10.1109/TIE.2013.2259782 (DOI)000329055300039 ()
    Tilgjengelig fra: 2013-12-05 Laget: 2013-12-05 Sist oppdatert: 2017-12-06bibliografisk kontrollert
  • 25.
    Abrahamsson, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Kinetic Energy Storage and Magnetic Bearings, for vehicular applications2011Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    One of the main challenges in order to make electric cars competitive with gaspowered cars is in the improvement of the electric power system. Although many of the energy sources currently used in electric vehicles have sufficiently high specific energy, their applicability is limited due to low specific power. It would therefore be advantageous to create a driveline with the main energy storage separated from a smaller energy buffer, designed to have high power capabilities and to withstand frequent and deep discharge cycles. It has been found that rotating kinetic energy storage in flywheels is very well suited for this type of application. The work presented in this thesis and the included papers span a number of topcis Introductory overview - This section explains the concept of the modern flywheel, and investigates some of its properties. It illustrates the concepts with a number of examples, relevant for the usage of flywheels in vehicular applications. Experimental set-up - The construction of a complete electric driveline is ongoing within the division for Electricity at Uppsala University. An optimized electric machine has been constructed and connected with a programmable load, as well as with a DC power source through power electronics controlled by PWM. As a part of this system, an experimental set-up of an active magnetic bearing for two degrees-of-freedom has been constructed. The work with this device is described in detail and some preliminary results are presented. Self-bearing machine - The electric machine developed for the existing driveline is coreless, double wound and with a double rotor. In order to achieve magnetic bearing functionality in this device for all DOF, a novel Lorentz force self-bearing machine is suggested. The design is analyzed analytically and numerically.

  • 26.
    Abrahamsson, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Magnetic bearings in kinetic energy storage systems for vehicular applications2011Inngår i: Journal of Electrical Systems, ISSN 1112-5209, Vol. 7, nr 2, s. 225-236Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The rotating Kinetic Energy Storage System (KESS) is suitable as temporary energy storage in electric vehicles due to its insensitivity to the number of charge-discharge cycles and its relatively high specific energy. The size and weight of the KESS for a given amount of stored energy are minimized by decreasing the moment of inertia of the rotor and increasing its speed. A small and fast rotor has the additional benefit of reducing the induced gyroscopic moments as the vehicle turns. The very high resulting rotational speed makes the magnetic bearing an essential component of the system, with the Active Magnetic Bearing (AMB) being the most common implementation. The complexity and cost of an AMB can be reduced by integration with the electric machine, resulting in a bearingless and sensorless electric machine. This review article describes the usage of magnetic bearings for FESS in vehicular applications.

  • 27.
    Abrahamsson, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    de Santiago, Juan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Oliveira, Janaína Gonçalves de
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Lundin, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Prototype of electric driveline with magnetically levitated double wound motor2010Inngår i: Electrical Machines (ICEM), 2010 XIX International Conference on, 2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents the ongoing work of constructing a complete driveline for an electric road vehicle, using a flywheel as auxiliary energy storage. The flywheel energy storage system (FESS) is connected in series between the main energy storage (batteries) and the wheel motor of the vehicle, allowing the batteries to deliver power to the system in an optimized way, while at the same time making efficient use of regenerative braking. A double wound permanent magnet electric machine is used to electrically separate the two sides. In order to minimize losses, the machine has a double rotor configuration and is suspended with magnetic bearings. A bench test set-up is being constructed to investigate the properties of this system in detail. This set-up will achieve a level of power and energy close to that of a full scale system. This will allow measurements of complete drive cycles to be performed, improving the understanding of the constituting components and optimization of the complete system.

  • 28.
    Abrahamsson, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Gonçalves de Oliveira, Janaína
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    de Santiago, Juan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Lundin, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    On the Efficiency of a Two-Power-Level Flywheel-Based All-Electric Driveline2012Inngår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 5, nr 8, s. 2794-2817Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents experimental results on an innovative electric driveline employing a kinetic energy storage device as energy buffer. A conceptual division of losses in the system was created, separating the complete system into three parts according to their function. This conceptualization of the system yielded a meaningful definition of the concept of efficiency. Additionally, a thorough theoretical framework for the prediction of losses associated with energy storage and transfer in the system was developed. A large number of spin-down tests at varying pressure levels were performed. A separation of the measured data into the different physical processes responsible for power loss was achieved from the corresponding dependence on rotational velocity. This comparison yielded an estimate of the perpendicular resistivity of the stranded copper conductor of 2.5 x 10(-8) +/- 3.5 x 10(-9). Further, power and energy were measured system-wide during operation, and an analysis of the losses was performed. The analytical solution was able to reproduce the measured distribution of losses in the system to an accuracy of 4.7% (95% CI). It was found that the losses attributed to the function of kinetic energy storage in the system amounted to between 45% and 65%, depending on usage.

  • 29.
    Abrahamsson, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Hedlund, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Prototype of Kinetic Energy Storage System for Electrified Utility Vehicles in Urban Traffic2012Konferansepaper (Fagfellevurdert)
  • 30.
    Abrahamsson, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Hedlund, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Kamf, Tobias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    High-Speed Kinetic Energy Buffer: Optimization of Composite Shell and Magnetic Bearings2014Inngår i: IEEE transactions on industrial electronics (1982. Print), ISSN 0278-0046, E-ISSN 1557-9948, Vol. 61, nr 6, s. 3012-3021Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents the design and optimization of a high-speed (30 000 r/min) kinetic energy storage system. The purpose of the device is to function as an energy buffer storing up to 867 Wh, primarily for utility vehicles in urban traffic. The rotor comprises a solid composite shell of carbon and glass fibers in an epoxy matrix, constructed in one curing. The shell is optimized using a combined analytical and numerical approach. The radial stress in the shell is kept compressive by integrating the electric machine, thereby avoiding delamination. Radial centering is achieved through eight active electromagnetic actuators. The actuator geometry is optimized using a direct coupling between SolidWorks, Comsol, and Matlab for maximum force over resistive loss for a given current density. The optimization results in a system with 300% higher current stiffness than the reference geometry with constant flux area, at the expense of 33% higher power loss. The actuators are driven by semipassive H bridges and controlled by an FPGA. Current control at 20 kHz with a noise of less than 5 mA (95% CI) is achieved, allowing position control at 4 kHz to be implemented.

  • 31.
    Abrahamsson, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Ögren, Jim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Hedlund, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    A Fully Levitated Cone-Shaped Lorentz-Type Self-Bearing Machine With Skewed Windings2014Inngår i: IEEE transactions on magnetics, ISSN 0018-9464, E-ISSN 1941-0069, Vol. 50, nr 9, artikkel-id 8101809Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Brushless dc coreless electric machines with double-rotor and single-stator configuration have very low losses, since the return path of the magnetic flux rotates with the permanent magnets. The eddy-current loss in the stator is additionally very small due to the lack of iron, making it ideal for kinetic energy storage. This paper presents a design for self-bearing rotor suspension, achieved by placing the stator windings skewed on a conical surface. A mathematical analysis of the force from a skewed winding confined to the surface of a cone was found. The parametric analytical expressions of the magnitude and direction of force and torque were verified by finite-element method simulations for one specific geometry. A dynamic model using proportional-integral-differential control was implemented in MATLAB/Simulink, and the currents needed for the self-bearing effect were found by solving an underdetermined system of linear equations. External forces, calculated from acceleration measurements from a bus in urban traffic, were added to simulate the dynamic environment of an electrical vehicle.

  • 32.
    Abrahamsson, Niklas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    Individuell mätning och debitering av värme i flerbostadshus: Svenska förutsättningar i jämförelse med erfarenheter från Tyskland och Danmark2013Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    I Sverige är det idag ovanligt att man i flerbostadshus använder sig av individuell mätning och debitering av energi för uppvärmning. Med individuell mätning och debitering menas att hyresgästen debiteras efter sin individuella förbrukning per lägenhet. Detta är mer vanligt i övriga Europa och den här studien syftar till att få kunskap om erfarenheter och problemställningar inom detta område från Tyskland och Danmark. Dessa länder har sedan länge en hög andel användare av systemet samt även lagstiftning om obligatorisk mätning och debitering på individuell nivå.

    Studien görs på uppdrag av Sveriges allmännyttiga bostadsföretag (SABO), Hyresgästföreningen och Fastighetsägarna. Den är en del av ett projekt där dessa organisationer tillsammans ska försöka komma fram till en central rekommendation som kan gälla för dess medlemmar vid införande av individuell mätning. Skillnader som undersöks länderna emellan är klimat, fastigheters energiprestanda, vanor, hyressättningssystem, affärsmodell för energiförsäljning samt lagstiftning.

    I rapporten beskrivs också de tekniker man använder samt dess för- och nackdelar. Målet med arbetet är att öka förståelsen och kunskapen inom området samt visa på andra länders erfarenheter och lösningar.

    Vad man kan se av jämförelsen är att Sverige i många fall har liknande förutsättningar som Tyskland och Danmark. Det finns även en del skillnader. Exempelvis kan det i Sverige vara svårt att föra över värmekostnaden separat från grundhyran, vilket inte varit något problem i Tyskland där man redan har kallhyra för sig och driftskostnader för sig. Däremot skulle man förmodligen i Sverige spara mer energi vid ett införande av ett sådant system, i absoluta tal på grund av vårt kallare klimat. Vad gäller lagstiftningen inom området i Danmark och Tyskland kan man se att den fungerar på ett liknande sätt. Det europeiska energidirektivet, EED, skulle om det går igenom i sin nuvarande form kunna tvinga även Sverige att lagstifta om ett obligatoriskt införande av individuell mätning och debitering.

  • 33.
    Abro, Mehwish
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Modelling the exfoliation of graphite for production of graphene2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aim of my thesis is to make a theoretical model of data obtained from liquid-phase exfoliation of graphene. The production of graphene in the liquid phase exfoliation is a cost efficient method One part of this work is devotedto learn the method of production of graphene by the shear mixing technique from the graphite and to estimate some important parameters which are crucial for the process. Other part of my work is based on studying the liquid-phase exfoliation mechanism of graphene through ultrasonication technique. This method is time consuming as compared to shearmixing.

  • 34.
    Absil, Oliver
    et al.
    Université de Liège, Belgium.
    Mawet, Dimitri
    California Institute of Technology/Jet Propulsion Laboratory, USA.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Carlomagno, Brunella
    Université de Liège, Belgium.
    Christiaens, Valentin
    Universidad de Chile, Chile.
    Defrère, Denis
    Université de Liège, Belgium.
    Delacroix, Christian
    Cornell University, USA.
    Femenía Castellá, Bruno
    W. M. Keck Observatory, USA.
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Girard, Julien
    European Southern Observatory, Chile.
    Gómez González, Carlos A.
    Université de Liège, Belgium.
    Habraken, Serge
    Université de Liège, Belgium.
    Hinz, Philip M.
    University of Arizona, USA.
    Huby, Elsa
    Université de Liège, Belgium.
    Jolivet, Aissa
    Université de Liège, Belgium.
    Matthews, Keith
    California Institute of Technology, USA.
    Milli, Julien
    European Southern Observatory, USA.
    Orban de Xivry, Gilles
    Université de Liège, Belgium.
    Pantin, Eric
    Université Paris Diderot, France.
    Piron, Pierre
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Reggiani, Maddalena
    Université de Liège, Belgium.
    Ruane, Garreth J.
    California Institute of Technology, USA.
    Serabyn, Eugene
    Jet Propulsion Laboratory, USA.
    Surdej, Jean
    Université de Liège, Belgium.
    Tristram, Konrad R. W.
    European Southern Observatory, Chile.
    Vargas Catalan, Ernesto
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wertz, Olivier
    Université de Liège, Belgium.
    Wizinowich, Peter
    W. M. Keck Observatory, USA.
    Three years of harvest with the vector vortex coronagraph in the thermal infrared2016Inngår i: Ground-Based and Airborne Instrumentation for Astronomy VI: 26-30 June 2016, Edinburgh, United Kingdom / [ed] Christopher J Evans, SPIE - International Society for Optical Engineering, 2016, Vol. 9908, s. 1-14, artikkel-id 99080Q-1Konferansepaper (Fagfellevurdert)
    Abstract [en]

    For several years, we have been developing vortex phase masks based on sub-wavelength gratings, known as Annular Groove Phase Masks. Etched onto diamond substrates, these AGPMs are currently designed to be used in the thermal infrared (ranging from 3 to 13 μm). Our AGPMs were first installed on VLT/NACO and VLT/VISIR in 2012, followed by LBT/LMIRCam in 2013 and Keck/NIRC2 in 2015. In this paper, we review the development, commissioning, on-sky performance, and early scientific results of these new coronagraphic modes and report on the lessons learned. We conclude with perspectives for future developments and applications.

  • 35. Absil, Olivier
    et al.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Mawet, Dimitri
    Carlomagno, Brunella
    Christiaens, Valentin
    Delacroix, Christian
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Gomez Gonzales, Carlos
    Habraken, Serge
    Jolivet, Aïssa
    Piron, Pierre
    Van Droogenbroeck, Marc
    Vargas Catalan, Ernesto
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Absil, Pierre-Antoine
    Boccaletti, Anthony
    Baudoz, Pierre
    Defrère, Dennis
    Milli, Julien
    Surdej, Sean
    Optimized, high performance vortex coronagraphs for E-ELT instruments2014Konferansepaper (Fagfellevurdert)
  • 36. Absil, Olivier
    et al.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Mawet, Dimitri
    Carlomagno, Brunella
    Christiaens, Valentin
    Delacroix, Christian
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Gomez Gonzales, Carlos
    Habraken, Serge
    Jolivet, Aïssa
    Piron, Pierre
    Van Droogenbroeck, Marc
    Vargas Catalan, Ernesto
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Absil, Pierre-Antoine
    Boccaletti, Anthony
    Baudoz, Pierre
    Defrère, Dennis
    Milli, Julien
    Surdej, Sean
    Reaching the diffraction limit with the vortex coronagraph2014Konferansepaper (Fagfellevurdert)
  • 37. Absil, Olivier
    et al.
    Mawet, Dimitri
    Delacroix, Christian
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Habraken, Serge
    Surdej, Jean
    Absil, Pierre-Antoine
    Carlomagno, Brunella
    Christiaens, Valentin
    Defrere, Denis
    Gonzalez, Carlos Gomez
    Huby, Elsa
    Jolivet, Aissa
    Milli, Julien
    Piron, Pierre
    Catalan, Ernesto Vargas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Van Droogenbroeck, Marc
    The VORTEX project: first results and perspectives2014Inngår i: Adaptive Optics Systems IV, 2014, artikkel-id 91480MKonferansepaper (Fagfellevurdert)
    Abstract [en]

    Vortex coronagraphs are among the most promising solutions to perform high contrast imaging at small angular separations from bright stars. They feature a very small inner working angle (down to the diffraction limit of the telescope), a clear 360 degree discovery space, have demonstrated very high contrast capabilities, are easy to implement on high-contrast imaging instruments, and have already been extensively tested on the sky. Since 2005, we have been designing, developing and testing an implementation of the charge-2 vector vortex phase mask based on concentric sub-wavelength gratings, referred to as the Annular Groove Phase Mask (AGPM). Science-grade mid-infrared AGPMs were produced in 2012 for the first time, using plasma etching on synthetic diamond substrates. They have been validated on a coronagraphic test bench, showing broadband peak rejection up to 500: 1 in the L band, which translates into a raw contrast of about 6 x 10(-5) at 2 lambda/D. Three of them have now been installed on world-leading diffraction-limited infrared cameras, namely VLT/NACO, VLT/VISIR and LBT/LMIRCam. During the science verification observations with our L-band AGPM on NACO, we observed the beta Pictoris system and obtained unprecedented sensitivity limits to planetary companions down to the diffraction limit (0 : 1 0 0). More recently, we obtained new images of the HR 8799 system at L band during the AGPM first light on LMIRCam. After reviewing these first results obtained with mid-infrared AGPMs, we will discuss the short-and mid-term goals of the on-going VORTEX project, which aims to improve the performance of our vortex phase masks for future applications on second-generation high-contrast imager and on future extremely large telescopes (ELTs). In particular, we will briefly describe our current efforts to improve the manufacturing of mid-infrared AGPMs, to push their operation to shorter wavelengths, and to provide deeper starlight extinction by creating new designs for higher topological charge vortices. Within the VORTEX project, we also plan to develop new image processing techniques tailored to coronagraphic images, and to study some pre- and post-coronagraphic concepts adapted to the vortex coronagraph in order to reduce scattered starlight in the final images.

  • 38. Absil, Olivier
    et al.
    Mawet, Dimitri
    Karlsson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Habraken, Serge
    Surdej, Jean
    Absil, Pierre-Antoine
    Carlomagno, Brunella
    Christiaens, Valentin
    Defrère, Denis
    Forsberg, Pontus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Girard, Julien
    Gomez Gonzalez, Carlos
    Hinz, Philip
    Huby, Elsa
    Jolivet, Aïssa
    Milli, Julien
    Pantin, Eric
    Ruane, Garreth
    Serabyn, Eugene
    Van Droogenbroeck, Marc
    Vargas Catalan, Ernesto
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Wertz, Olivier
    An update on the VORTEX project2015Inngår i: Techniques and Instrumentation for Detection of Exoplanets VII, 2015, Vol. 9605Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this talk, we will review the on-going activities within the VORTEX teamat the University of Liège and Uppsala University. The VORTEX project aimsto design, manufacture, test, and exploit vector vortex phase masks madeof sub-wavelength gratings (aka the Annular Groove Phase Mask, AGPM)for the direct detection and characterization of extrasolar planets. This talkwill specifically report on the commissioning of several AGPMs on infraredcameras equipping 10-m class telescopes, including the VLT, the LBT andthe Keck. We will describe the in-lab and on-sky performance of the AGPMs,and discuss first scientific observations. We will also report on the lessonslearned from the on-sky operation of our vortices, and discuss ways toimprove their performance. The potential of our coronagraphic devices inthe context of future extremely large telescopes and space missions will alsobe addressed.

  • 39.
    Abujheisha, Belal
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Laserinkopplingselement För XFEL Laser Heater: Från Idé Till Färdig Produkt I Designstadie2011Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    Uppsala University is involved in a large international collaborationto build the Laser heater system for the European Xray Free-electronlaser in Hamburg, Germany. In this thesis I describe a laser incouplingdevice into the vacuum chamber of this laser heater all the way fromthe specifications to a completed design.

    The laser heater is a very important part of the XFEL and thepart described here is a part of the vacuum system needed to couplean external laser into the electron vacuum system and align it withthe electron bunches in order to heat them. The task was started by studying the literature about the basic theory andthe design of vacuum systems. After this study and collection of ideaswith colleagues I started to prepare different concepts to solve thetask. The ideas can be put into two categories, in one case the couplingmirror is located inside the vacuum chamber and in the second caseoutside. The concepts were evaluated with colleagues from the physicsdepartment and one solution from each category was evaluated further. The work continued to develop and refine these concpets. During the workseveral obstacles appeared, the biggest one was that with the 'inside'concept some of the design constraints had to be disregarded, butduring further work the design was adapted and the problems weremostly solved.

    The concept with the mirror outside the vacuumchamber was succesfuland the design was completed. In this thesis SolidWorks was used for the design work of thedifferent concepts and all parts that are part of the icouplingelement for the XFEL laser heater. All drawings are generated inSolidWorks as well and are attached to this report.

  • 40.
    Abuzohri, Ahmed
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Industriell teknik.
    Business Development: Market research & feasibility study of a PV-wind hybrid system for commercial use2018Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    The definition of environmental sustainability has emerged strongly in the past decades. Industrial organizations worldwide have gone through a number of changes to take their social responsibilities and maintain sustainability by, among other things, replacing the conventional energy-based applications by renewable energy-based solutions. A so-called hybrid power system for electrification, consisting of wind turbines and solar panels, was developed by Vertical Wind AB to be installed on rooftops of residential buildings. The present thesis project analyzed the willingness of the large real estate companies in Uppsala region to adopt the new concept for electrification and conducted a market research on the new developed wind turbines, by Vertical Wind AB, in addition to solar- and wind resources in the target locations. It turned out that the willingness of having such a power system for electrification was high but not extremely high as expected and the hybrid power system was perceived as any other product or investment on the market where profitability is the vital decision parameter while the environmental aspect was slightly considered.

  • 41.
    Abuzohri, Ahmed
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Effektförstärkare med strömkontroll2012Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Energin är ett begrepp som används dagligen i vårt samhälle. Energin kan inte skapas men däremot kan den omvandlas till olika former, förbrukas och lagras i vissa fall. Men att omvandla energi från en form till en annan form för att sedan lagra den är en av dagens stora utmaningar inom tekniken då vi måste följa de regler som naturen dikterar. Forskning på detta område har pågått i flera decennier för att kunna ta fram lämpliga och effektiva sätt att lagra energi på. Svänghjul-system är ett sådant sätt där man kan lagra energi under begränsad tid.

    I mitt examensarbete har jag utnyttjat kunskapen som jag har lärt mig från elektronik kurserna för att konstruera en effektförstärkare med strömkontroll som användes för att driva ett svänghjul-system. Förstärkaren har byggts med elektronikkomponenter och styrs från datorn med m.h.a. styrprogrammet LabVIEW som kommunicerar med hårdvaran och kontrollerar svänghjulets rörelse.

  • 42.
    Abuzohri, Ahmed
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Dizdarevic, Zlatko
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Skapa öppenhet i erfarenhetsregistrering vid Forsmarks Kraftgrupp AB2012Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Denna rapport är resultatet av ett examensarbete som utfördes på Forsmarks kärnkraftverk åt FTQ-avdelningen. FTQ-avdelning på Forsmark ansvarar för erfarenhetsåterföringens ärenden på anläggningen och försörjer organisationen med nya infallsvinklar gällande erfarenhetsåterföringstekniken. För cirka 10 år kom Forsmarks kraftgrupp AB till insikt att det fanns ett behov av att införa en aktiv erfarenhetsåterföringsprocess för att undvika upprepade misstag. Detta resulterade i att en ny avdelning skapades år 2008 med namnet FTQ. Denna avdelning skapade en databas med namnet ERFKA där man började samla in och lagra erfarenhetsåterföringsärenden. Dessutom innehåller ERFKA ett presentationsverktyg som möjliggör för personalen på FTQ-avdelningen att få fram grafisk statistik på allt som finns i databasen, som t.ex. statistik på tillbud, olyckor, månadsrapporter, rapporter mm. ERFKA-systemet uppfyller sitt syfte i detta sammanhang, men är på grund av sekretesskäl endast tillgänglig för ett tiotal personer. Det resulterar i att FTQ-avdelningen kontaktas för att ta fram informationen åt andra på anläggningen vilket både är tidskrävande och krångligt i en stor organisation som Forsmark.

    Examensjobbet mål var att skapa öppenhet i ERFKA-systemet. Genom att använda befintliga IT- verktyg utöver ERFKA ska informationen i ERFKA göras tillgänglig för alla på Forsmark.

    Examensarbetet består av två delar. Den ena består av framtagning och bearbetning av information från användare av ERFKA och den andra av framtagande av lösningförslag. I första delen utfördes intervjuer för att kartlägga vilken information som ska göras tillgänglig för personalen. Intervjuer hölls med de personer som var mest insatta i erfarenhetsåterföringsförbättringen och därmed var projektets främsta intressenter.

    I den andra delen togs det fram en kopplingsmodell för att presentera informationen från ERFKA på Forsmarks interna webbplats "Canalen". På grund av begränsad åtkomst till ERFKA för samtaliga anställda blev lösningen att flytta informationen från ERFKA till ett redan beprövat grafritandestatistikprogram med namnet Bi-Cycle. Detta program är tillgänglig för alla i organisationen, enligt bestämda specifikationer.

    Under projektets gång skapades ett schema på en möjlig kopplingsmodell där alla steg i kommunikationen visas tydligt. Modellen inkluderar allt från Canalen och grafer i Bi-Cycle till den slutgiltiga rapporten och några möjliga kopplingsmodeller mellan ERFKA och Bi-Cycle

  • 43. Ackeby, Susanne
    et al.
    Bollen, Math
    Munkhammar, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Prosumer with demand-response: Distribution network impact and mitigation2013Rapport (Fagfellevurdert)
  • 44.
    Ackeby, Susanne
    et al.
    STRI.
    Bollen, Math
    Luleå tekniska universitet.
    Munkhammar, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Prosumer with demand-response:Distribution network impact and mitigation2013Rapport (Annet vitenskapelig)
    Abstract [en]

    This report is the result from a project funded by ELFORSK done by STRI. Theproject is studying the effects the introduction of so called “prosumers”(customers with own production) and electrical vehicles will have on differenttypes of networks. Four different cases are studied: covering urban and ruralareas with different types of customers.In the urban areas the power through the transformer will be the limitingfactor. The major impact in the cases studied is from the introduction ofproduction from photovoltaics at the customer-side of the meter. This willresult in an introduction of surplus due to production which in one case led toan increase of the absolute power through the transformer with more than30%, which resulted in transformer overloading.In the rural areas the voltage drop or rise will be the limiting factor. The casesstudied had already high voltage drops even in the base cases. In the casestudies it was seen that the voltage drop could be slightly reduced whenintroducing more local production, but the production also led to that voltagerise could appear. As a result the interval of the voltage variations wasincreased, which in turn leads to difficulties with designing the network suchthat neither overvoltage nor undervoltage occurs.Introducing control algorithms had a very positive effect on reducing the netproduction from the photovoltaics. Using both hard and soft curtailment madeit possible to remove all overcurrents or overvoltages. Using hard curtailment,where all production is turned off during overcurrent or overvoltage, leadshowever to a large reduction in energy from renewable energy sources.Therefore soft curtailment should as much as possible be used.The control algorithms studied for reducing the net consumption had a morelimited effect and even resulted in an increase of the maximum netconsumption. When trying to reduce the net consumption during an overload,the reason of the overload could only be moved in time and not removed as inthe case of reducing the net production. And since often the period duringwhich the power exceeds the limit is longer than the number of hours possibleto move the energy, sometimes moving the energy had an adverse effect.The model used for controlling the net consumption needs furtherdevelopment, but it is still possible to draw the conclusion that this type ofcontrol offers only limited possibilities for mitigating overload or undervoltage.The effects of introducing prosumers and more electrical vehicles as defined inthe selected cases did not show any alarming results in this study. However,studies to learn more about the possible consequences of changes atcustomer-side are important to be able to handle the impact of such changeson the network.Further future studies needed: database with load and production data;improved control algorithms; demonstration project; experience from othercountries and studies on reactive power compensation.

  • 45.
    Adams, Christopher
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Secondary and Higher Order Structural Characterization of Peptides and Proteins by Mass Spectrometry2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The work in this thesis has demonstrated the advantages and limitations of using MS based technologies in protein and peptide structural studies.

    Tandem MS, specifically electron capture dissociation (ECD) have shown the ability to provide structural insights in molecules containing the slightest of all modifications (D-AA substitution). Additionally, it can be concluded that charge localization in molecular ions is best identified with ECD and to a lesser degree using CAD.

    Fragment ion abundances are a quantifiable tool providing chiral recognition (RChiral). An analytical model demonstrating the detection and quantification of D-AAs within proteins and peptides has been achieved. ECD has demonstrated the ability to quantify stereoisomeric mixtures to as little as 1%. Chirality elucidation on a nano LC-MS/MS time scale has been shown.

    The structures of various stereoisomers of the mini protein Trp Cage were explored, each providing unique ECD fragment ion abundances suggestive of gas phase structural differences. The uniqueness of these abundances combined with MDS data have been used in proposing a new mechanism in c and z fragment ion formation in ECD. This mechanism suggests initial electron capture on a backbone amide involved in (neutral) hydrogen bonding.

    The wealth of solution phase (circular dichroism), transitition phase (charge state distribution, CSD) and gas phase (ECD) data for Trp Cage suggest that at low charge states (2+) the molecule has a high degree of structural similarity in solution- and gas- phases. Furthermore, quantitative information from CSD studies is garnered when using a “native” deuteriated form as part of the stereoisomeric mixture. It has also been shown that the stability of the reduced species after electron capture is indicative of the recombination energy release, which in turn is linked to the coulombic repulsion- a structural constraint that can be used for approximation of the inter-charge distance for various stereoisomers.

    Delarbeid
    1. Electron capture dissociation distinguishes a single D-amino acid in a protein and probes the tertiary structure
    Åpne denne publikasjonen i ny fane eller vindu >>Electron capture dissociation distinguishes a single D-amino acid in a protein and probes the tertiary structure
    Inngår i: Journal of The American Society for Mass Spectrometry, ISSN 1044-0305, Vol. 15, nr 7, s. 1087-1098Artikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-95861 (URN)
    Tilgjengelig fra: 2007-05-07 Laget: 2007-05-07bibliografisk kontrollert
    2. Determination of the location of positive charges in gas-phase polypeptide polycations by tandem mass spectrometry
    Åpne denne publikasjonen i ny fane eller vindu >>Determination of the location of positive charges in gas-phase polypeptide polycations by tandem mass spectrometry
    2006 (engelsk)Inngår i: International Journal of Mass Spectrometry, ISSN 1387-3806, E-ISSN 1873-2798, Vol. 252, nr 3, s. 204-212Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Location of protonated sites in electrospray-ionized gas-phase peptides and proteins was performed with tandem mass spectrometry using ion activation by both electron capture dissociation (ECD) and collisional activation dissociation (CAD). Charge-carrying sites were assigned based on the increment in the charge state of fragment ions compared to that of the previous fragment in the same series. The property of ECD to neutralize preferentially the least basic site was confirmed by the analysis of three thousand ECD mass spectra of doubly charged tryptic peptides. Multiply charged cations of bradykinin, neurotensin and melittin were studied in detail. For n+ precursors, ECD revealed the positions of (n − 1) most basic sites, while CAD could in principle locate all n charges. However, ECD introduced minimal proton mobilization and produced more conclusive data than CAD, for which N- and C-terminal data often disagreed. Consistent with the dominance of one charge conformer and its preservation in ECD, the average charge states of complementary fragments of n+ ions almost always added up to (n − 1)+, while the similar figure in CAD often deviated from n+, indicating extensive charge isomerization under collisional excitation. For bradykinin and neurotensin, the charge assignments were largely in agreement with the intrinsic gas-phase basicity of the respective amino acid residues. For melittin ions in higher charge states, ECD revealed the charging at both intrinsically basic as well as at less basic residues, which was attributed to charge sharing with other groups due to the presence of secondary and higher order structures in this larger polypeptide.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-95862 (URN)10.1016/j.ijms.2005.10.009 (DOI)
    Tilgjengelig fra: 2007-05-07 Laget: 2007-05-07 Sist oppdatert: 2017-12-14bibliografisk kontrollert
    3. Distinguishing and quantifying peptides and proteins containing D-amino acids by tandem mass spectrometry
    Åpne denne publikasjonen i ny fane eller vindu >>Distinguishing and quantifying peptides and proteins containing D-amino acids by tandem mass spectrometry
    Inngår i: Analytical Chemistry, ISSN 0003-2700, Vol. 77, nr 14, s. 4571-4580Artikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-95863 (URN)
    Tilgjengelig fra: 2007-05-07 Laget: 2007-05-07bibliografisk kontrollert
    4. Prediction of N-C-alpha bond cleavage frequencies in electron capture dissociation of Trp-cage dications by force-field molecular dynamics simulations
    Åpne denne publikasjonen i ny fane eller vindu >>Prediction of N-C-alpha bond cleavage frequencies in electron capture dissociation of Trp-cage dications by force-field molecular dynamics simulations
    Vise andre…
    Inngår i: International Journal of Mass Spectrometry, ISSN 1387-3806, Vol. 248, nr 3, s. 124-135Artikkel i tidsskrift (Fagfellevurdert) Published
    Identifikatorer
    urn:nbn:se:uu:diva-95864 (URN)
    Tilgjengelig fra: 2007-05-07 Laget: 2007-05-07bibliografisk kontrollert
    5. Probing Solution-Phase and Gas-Phase Structures of Trp-cage Cations by Chiral Substitution and Spectroscopic Techniques
    Åpne denne publikasjonen i ny fane eller vindu >>Probing Solution-Phase and Gas-Phase Structures of Trp-cage Cations by Chiral Substitution and Spectroscopic Techniques
    Vise andre…
    2006 (engelsk)Inngår i: International Journal of Mass Spectrometry, ISSN 1387-3806, E-ISSN 1873-2798, Vol. 253, nr 3, s. 263-273Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The relevance of gas-phase protein structure to its solution structure is of the utmost importance in studying biomolecules by mass spectrometry. D-Amino acid substitutions within a minimal protein. Trp-cage. were used to correlate solution-phase properties as measured by circular dichroism with solution/gas-phase conformational features of protein cations probed via charge state distribution (CSD) in electrospray ionization. and gas-phase features revealed by tandem mass spectrometry (MS/MS). The gas-phase features were additionally supported by force-field molecular dynamics simulations. CD data showed that almost any single-residue D-substitution destroys the most prominent CD feature of the "native" all-L isomer, alpha-helicity. CSD was able to qualitatively assess the degree of compactness of solution-phase molecular structures. CSD results were consistent with the all-L form being the most compact in solution among all studied stereoisomers except for the D-Asn(1) isomer. D-substitutions of the aromatic Y(3), W(6) and Q(5) residues generated the largest deviations in CSD data among single amino acid substitutions. consistent with the critical role of these residues in Trp-cage stability. Electron capture dissociation of the stereoisomer dications gave an indication that some gas-phase structural features of Trp-cage are similar to those in solution. This result is supported by MDS data oil five of the studied stereoisomer dications in the gas-phase. The MDS-derived minimum-energy structures possessed more extensive hydrogen bonding than the solution-phase structure of the native form, deviating from the latter by 3-4 angstrom and were not 'inside-out' compared to native structures. MDS data could be correlated with CD data and even with ECD results. which aided in providing a long-range structural constraint for MDS. The overall conclusion is the general resemblance, despite the difference on the detailed level, of the preferred structures in both phases for the mini protein Trp-cage.

    Emneord
    solution structure; gas-phase structure; chirality; electron capture dissociation; charge state distribution
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-95865 (URN)10.1016/j.ijms.2006.04.012 (DOI)000238967500014 ()
    Tilgjengelig fra: 2007-05-07 Laget: 2007-05-07 Sist oppdatert: 2017-12-14bibliografisk kontrollert
  • 46.
    Adams, Christopher
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Kjeldsen, Frank
    Haselmann, Kim
    Zubarev, Roman
    Electron capture dissociation distinguishes a single D-amino acid in a protein and probes the tertiary structureInngår i: Journal of The American Society for Mass Spectrometry, ISSN 1044-0305, Vol. 15, nr 7, s. 1087-1098Artikkel i tidsskrift (Fagfellevurdert)
  • 47.
    Adams, Christopher
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Kjeldsen, Frank
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Jonfysik.
    Patriksson, Alexandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi.
    van Der Spoel, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Molekylär biofysik.
    Gräslund, Astrid
    Papadopolous, Evangelos
    Zubarev, Roman
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi.
    Probing Solution-Phase and Gas-Phase Structures of Trp-cage Cations by Chiral Substitution and Spectroscopic Techniques2006Inngår i: International Journal of Mass Spectrometry, ISSN 1387-3806, E-ISSN 1873-2798, Vol. 253, nr 3, s. 263-273Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The relevance of gas-phase protein structure to its solution structure is of the utmost importance in studying biomolecules by mass spectrometry. D-Amino acid substitutions within a minimal protein. Trp-cage. were used to correlate solution-phase properties as measured by circular dichroism with solution/gas-phase conformational features of protein cations probed via charge state distribution (CSD) in electrospray ionization. and gas-phase features revealed by tandem mass spectrometry (MS/MS). The gas-phase features were additionally supported by force-field molecular dynamics simulations. CD data showed that almost any single-residue D-substitution destroys the most prominent CD feature of the "native" all-L isomer, alpha-helicity. CSD was able to qualitatively assess the degree of compactness of solution-phase molecular structures. CSD results were consistent with the all-L form being the most compact in solution among all studied stereoisomers except for the D-Asn(1) isomer. D-substitutions of the aromatic Y(3), W(6) and Q(5) residues generated the largest deviations in CSD data among single amino acid substitutions. consistent with the critical role of these residues in Trp-cage stability. Electron capture dissociation of the stereoisomer dications gave an indication that some gas-phase structural features of Trp-cage are similar to those in solution. This result is supported by MDS data oil five of the studied stereoisomer dications in the gas-phase. The MDS-derived minimum-energy structures possessed more extensive hydrogen bonding than the solution-phase structure of the native form, deviating from the latter by 3-4 angstrom and were not 'inside-out' compared to native structures. MDS data could be correlated with CD data and even with ECD results. which aided in providing a long-range structural constraint for MDS. The overall conclusion is the general resemblance, despite the difference on the detailed level, of the preferred structures in both phases for the mini protein Trp-cage.

  • 48.
    Adams, Christopher M
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Jonfysik. jonfysik.
    Kjeldsen, Frank
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Jonfysik. jonfysik.
    Zubarev, Roman A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Jonfysik. jonfysik.
    Budnik, Bogdan A
    jonfysik.
    Haselmann, Kim F
    Electron capture dissociation distinguishes a single D-amino acid in a protein and probes the tertiary structure.2004Inngår i: J Am Soc Mass Spectrom, ISSN 1044-0305, Vol. 15, nr 7, s. 1087-98Artikkel i tidsskrift (Fagfellevurdert)
  • 49.
    Adams, Christopher M
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för materialvetenskap. Institutionen för teknikvetenskaper, Jonfysik. Ion physics.
    Zubarev, Roman A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för materialvetenskap. Institutionen för teknikvetenskaper, Jonfysik. Ion physics.
    Distinguishing and quantifying peptides and proteins containing D-amino acids by tandem mass spectrometry.2005Inngår i: Anal Chem, ISSN 0003-2700, Vol. 77, nr 14, s. 4571-80Artikkel i tidsskrift (Fagfellevurdert)
  • 50.
    Adams, Christopher
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Zubarev, Roman
    Distinguishing and quantifying peptides and proteins containing D-amino acids by tandem mass spectrometryInngår i: Analytical Chemistry, ISSN 0003-2700, Vol. 77, nr 14, s. 4571-4580Artikkel i tidsskrift (Fagfellevurdert)
1234567 1 - 50 of 12917
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf