uu.seUppsala universitets publikationer
Ändra sökning
Avgränsa sökresultatet
45678910 301 - 350 av 534
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 301. Kish, Laszlo B.
    et al.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Enhanced Usage of Keys Obtained by Physical, Unconditionally Secure Distributions2015Ingår i: Fluctuation and Noise Letters, ISSN 0219-4775, E-ISSN 1793-6780, Vol. 14, nr 2, s. 1-3, artikel-id 1550007Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Unconditionally secure physical key distribution schemes are very slow, and it is practically impossible to use a one-time-pad based cipher to guarantee unconditional security for the encryption of data because using the key bits more than once gives out statistical information, for example via the known-plain-text-attack or by utilizing known components of the protocol and language statistics. Here, we outline a protocol that reduces this speed problem and allows almost-one-time-pad based communication with an unconditionally secure physical key of finite length. The physical, unconditionally secure key is not used for data encryption but is employed in order to generate and share a new software-based key without any known-plain-text component. The software-only-based key distribution is then changed from computationally secure to unconditionally secure, because the communicated key-exchange data (algorithm parameters, one-way functions of random numbers, etc.) are encrypted in an unconditionally secure way with a one-time-pad. For practical applications, this combined physical/software key distribution based communication looks favorable compared to the software-only and physical-only key distribution based communication whenever the speed of the physical key distribution is much lower than that of the software-based key distribution. A mathematical security proof of this new scheme remains an open problem.

  • 302. Kish, Laszlo B.
    et al.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    On the security of the Kirchhoff-law-Johnson-noise (KLJN) communicator2014Ingår i: Quantum Information Processing, ISSN 1570-0755, E-ISSN 1573-1332, Vol. 13, nr 10, s. 2213-2219Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A simple and general proof is given for the information theoretic (unconditional) security of the Kirchhoff-law-Johnson-noise key exchange system under practical conditions. The unconditional security for ideal circumstances, which is based on the second law of thermodynamics, is found to prevail even under slightly non-ideal conditions. This security level is guaranteed by the continuity of functions describing classical physical linear, as well as stable non-linear, systems. Even without privacy amplification, Eve's probability for successful bit guessing is found to converge toward 0.5-i.e., the perfect security level-when ideal conditions are approached.

  • 303.
    Kish, Laszlo B.
    et al.
    Department of Electrical Engineering, Texas A&M University, Texas USA.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Zero Thermal Noise in Resistors at Zero Temperature2016Ingår i: Fluctuation and Noise Letters, ISSN 0219-4775, E-ISSN 1793-6780, Vol. 15, nr 3, artikel-id 1640001Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The bandwidth of transistors in logic devices approaches the quantum limit, where Johnsonnoise and associated error rates are supposed to be strongly enhanced. However, the related theory — asserting a temperature-independent quantum zero-point (ZP) contribution to Johnson noise, which dominates the quantum regime — is controversial and resolution of the controversy is essential to determine the real error rate and fundamental energy dissipation limits of logic gates in the quantum limit. The Callen–Welton formula (fluctuation–dissipation theorem) of voltage and current noise for a resistance is the sum of Nyquist’s classical Johnson noise equation and a quantum ZP term with a power density spectrum proportional to frequency and independent of temperature. The classical Johnson–Nyquist formula vanishes at the approach of zero temperature, but the quantum ZP term still predicts non-zero noise voltage and current. Here, we show that this noise cannot be reconciled with the Fermi–Dirac distribution, which defines the thermodynamics of electrons according to quantum-statistical physics. Consequently,Johnson noise must be nil at zero temperature, and non-zero noise found for certain experimental arrangements may be a measurement artifact, such as the one mentioned in Kleen’s uncertainty relation argument.

  • 304.
    Kish, Laszlo B.
    et al.
    Texas A&M Univ, Dept Elect & Comp Engn, TAMUS 3128, College Stn, TX 77843 USA..
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Zero-point term and quantum effects in the Johnson noise of resistors: a critical appraisal2016Ingår i: Journal of Statistical Mechanics: Theory and Experiment, ISSN 1742-5468, E-ISSN 1742-5468, artikel-id 054006Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is a longstanding debate about the zero-point term in the Johnson noise voltage of a resistor. This term originates from a quantum-theoretical treatment of the fluctuation-dissipation theorem (FDT). Is the zero-point term really there, or is it only an experimental artifact, due to the uncertainty principle, for phase-sensitive amplifiers? Could it be removed by renormalization of theories? We discuss some historical measurement schemes that do not lead to the effect predicted by the FDT, and we analyse new features that emerge when the consequences of the zero-point term are measured via the mean energy and force in a capacitor shunting the resistor. If these measurements verify the existence of a zero-point term in the noise, then two types of perpetual motion machines can be constructed. Further investigation with the same approach shows that, in the quantum limit, the Johnson-Nyquist formula is also invalid under general conditions even though it is valid for a resistor-antenna system. Therefore we conclude that in a satisfactory quantum theory of the Johnson noise, the FDT must, as a minimum, include also the measurement system used to evaluate the observed quantities. Issues concerning the zero-point term may also have implications for phenomena in advanced nanotechnology.

  • 305.
    Kish, Laszlo Bela
    et al.
    Dept of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Electrical Maxwell Demon and Szilard Engine Utilizing Johnson Noise, Measurement, Logic and Control2012Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, nr 10, s. e46800-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We introduce a purely electrical version of Maxwell's demon which does not involve mechanically moving parts such as trapdoors, etc. It consists of a capacitor, resistors, amplifiers, logic circuitry and electronically controlled switches and uses thermal noise in resistors (Johnson noise) to pump heat. The only types of energy of importance in this demon are electrical energy and heat. We also demonstrate an entirely electrical version of Szilard's engine, i.e., an information-controlled device that can produce work by employing thermal fluctuations. The only moving part is a piston that executes work, and the engine has purely electronic controls and it is free of the major weakness of the original Szilard engine in not requiring removal and repositioning the piston at the end of the cycle. For both devices, the energy dissipation in the memory and other binary informatics components are insignificant compared to the exponentially large energy dissipation in the analog part responsible for creating new information by measurement and decision. This result contradicts the view that the energy dissipation in the memory during erasure is the most essential dissipation process in a demon. Nevertheless the dissipation in the memory and information processing parts is sufficient to secure the Second Law of Thermodynamics.

    Ladda ner fulltext (pdf)
    fulltext
  • 306.
    Kish, Laszlo Bela
    et al.
    Texas A&M Univ, Dept Elect & Comp Engn, College Stn, TX 77843 USA..
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Khatri, Sunil P.
    Texas A&M Univ, Dept Elect & Comp Engn, College Stn, TX 77843 USA..
    Peper, Ferdinand
    NICT, CiNet, 1-4 Yamadaoka, Suita, Osaka 5650871, Japan.;Osaka Univ, 1-4 Yamadaoka, Suita, Osaka 5650871, Japan..
    Response to "Comment on 'Zero and negative energy dissipation at information-theoretic erasure'"2016Ingår i: Journal of Computational Electronics, ISSN 1569-8025, E-ISSN 1572-8137, Vol. 15, nr 1, s. 343-346Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We prove that statistical information-theoretic quantities, such as information entropy, cannot generally be interrelated with the lower limit of energy dissipation during information erasure. We also point out that, in deterministic and error-free computers, the information entropy of memories does not change during erasure because its value is always zero. On the other hand, for information-theoretic erasure-i.e., "thermalization"/randomization of the memory-the originally zero information entropy (with deterministic data in the memory) changes after erasure to its maximum value, 1 bit/memory bit, while the energy dissipation is still positive, even at parameters for which the thermodynamic entropy within the memory cell does not change. Information entropy does not convert to thermodynamic entropy and to the related energy dissipation; they are quantities of different physical nature. Possible specific observations (if any) indicating convertibility are at most fortuitous and due to the disregard of additional processes that are present.

  • 307.
    Kish, Laszlo Bela
    et al.
    Texas A&M Univ, Dept Elect & Comp Engn, College Stn, TX 77843 USA..
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Khatri, Sunil P.
    Texas A&M Univ, Dept Elect & Comp Engn, College Stn, TX 77843 USA..
    Peper, Ferdinand
    Osaka Univ, NICT, CiNet, 1-4 Yamadaoka, Suita, Osaka 5650871, Japan..
    Zero and negative energy dissipation at information-theoretic erasure2016Ingår i: Journal of Computational Electronics, ISSN 1569-8025, E-ISSN 1572-8137, Vol. 15, nr 1, s. 335-339Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We introduce information-theoretic erasure based on Shannon's binary channel formula. It is pointed out that this type of erasure is a natural energy-dissipation-free way in which information is lost in double-potential-well memories, and it may be the reason why the brain can forget things effortlessly. We also demonstrate a new non-volatile, charge-based memory scheme wherein the erasure can be associated with even negative energy dissipation; this implies that the memory's environment is cooled during information erasure and contradicts Landauer's principle of erasure dissipation. On the other hand, writing new information into the memory always requires positive energy dissipation in our schemes. Finally, we show a simple system where even a classical erasure process yields negative energy dissipation of arbitrarily large energy.

  • 308. Kish, Laszlo Bela
    et al.
    Mingesz, Robert
    Gingl, Zoltan
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Spectra for the Product of Gaussian Noises2012Ingår i: METROL MEAS SYST, ISSN 0860-8229, Vol. 19, nr 4, s. 653-658Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Products of Gaussian noises often emerge as the result of non-linear detection techniques or as parasitic effects, and their proper handling is important in many practical applications, including fluctuation-enhanced sensing, indoor air or environmental quality monitoring, etc. We use Rice's random phase oscillator formalism to calculate the power density spectra variance for the product of two Gaussian band-limited white noises with zero-mean and the same bandwidth W. The ensuing noise spectrum is found to decrease linearly from zero frequency to 2W, and it is zero for frequencies greater than 2W. Analogous calculations performed for the square of a single Gaussian noise confirm earlier results. The spectrum at non-zero frequencies, and the variance of the square of a noise, is amplified by a factor two as a consequence of correlation effects between frequency products. Our analytic results are corroborated by computer simulations.

  • 309.
    Kish, Laszlo
    et al.
    Dept of Electrical Engineering, Texas A&M University, College Station, USA.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Bezrukov, Sergey M
    NIH Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD) National Institutes of Health (NIH) - USA.
    Horvath, Tamas
    Schloss Birlinghoven, Fraunhofer IAIS, Div Knowledge Discovery, D-53754 St Augustin, Germany, University of Bonn.
    Brain: Biological Noise-Based Logic2015Ingår i: Advances in Cognitive Neurodynamics (IV): Proceedings of the Fourth International Conference on Cognitive Neurodynamics 2013 / [ed] Hans Liljenström, Dordrecht, Tyskland: Springer Science+Business Media B.V., 2015, s. 319-322Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Neural spikes in the brain form stochastic sequences, i.e., belong to the class of pulse noises. This stochasticity is a counterintuitive feature because extracting information-such as the commonly supposed neural information of mean spike frequency-requires long times for reasonably low error probability. The mystery could be solved by noise-based logic, wherein randomness has an important function and allows large speed enhancements for special-purpose tasks, and the same mechanism is at work for the brain logic version of this concept.

  • 310.
    Kish, Lazar L.
    et al.
    Dept of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
    Kameoka, Jun
    Dept of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
    Granqvist, Claes G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kish, Laszlo B.
    Dept of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
    Optimum drift velocity for single molecule fluorescence bursts in micro/nano-fluidic channels2012Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, nr 4, s. 043120-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Photonic burst histograms can be used to identify single protein molecules in micro/nano-fluidic channels provided the width of the histogram is narrow. Photonic shot noise and residence time fluctuations, caused by longitudinal diffusion, are the major sources of the histogram width. This paper is a sequel to an earlier one of ours [L. L. Kish et al., Appl. Phys. Lett. 99, 143121 (2011)] and demonstrates that, for a given diffusion coefficient, an increase of the drift velocity enhances the relative shot noise and decreases the relative residence time fluctuations. This leads to an optimum drift velocity that minimizes the histogram width and maximizes the ability to identify single molecules, which is an important result for applications.

  • 311.
    Kish, Lazar L
    et al.
    Dept of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
    Kameoka, Jun
    Dept of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kish, Laszlo B
    Dept of Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA.
    Log-normal distribution of single molecule fluorescence bursts in micro/nano-fluidic channels2011Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 99, nr 14, s. 143121-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The width and shape of photon burst histograms pose significant limitations to the identification of single molecules in micro/nano-fluidic channels, and the nature of these histograms is not fully understood, To reach a deeper understanding, we performed computer simulations based on a Gaussian beam intensity profile with various fluidic channel diameters and assuming (1) a deterministic (noise-free) case, (2) photon emission/absorption noise, and (3) photon noise with diffusion. Photon noise in narrow channels yields a Gaussian burst distribution while additional strong diffusion produces skewed histograms. We use the fluctuating residence time picture Soderlund et al., Phys. Rev, Lett, 80, 2386 (1998)1 and conclude that the skewness of the photon number distribution is caused by the longitudinal diffusive component of the motion of the molecules as they traverse the laser beam. In the case of strong diffusion in narrow channels, this effect leads to a log-normal distribution. We show that the same effect can transform the separate peaks of the photon burst histograms of multiple molecule mixtures into a single log-normal shape.

  • 312. Kish, L.-B.
    et al.
    Abbott, D.
    Granqvist, C.-G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Wen, H.
    Facts, Myths and Fights about the KLJN Classical Physical Key Exchanger2014Ingår i: International Journal of Modern Physics E: Conf. Series, ISSN 0218-3013, Vol. 33, nr 1460362, s. 1-4Artikel i tidskrift (Refereegranskat)
  • 313. Kish, L.-B.
    et al.
    Bezrukov, S.
    Horvath, T.
    Granqvist, C.-G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Why is Neural Spike Transfer Stochastic? String Verification in the Brain2013Ingår i: 1) Abstracts 4th Int. Conf. Cognitive Neurodynamics2) Abstract Volume: Int. Conf. Hot Topics in Physical Informatics, 2013Konferensbidrag (Refereegranskat)
  • 314. Kish, L.-B.
    et al.
    Granqvist, C.-G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Electrical Noise Demons and Heretic Challenges about the Energy Cost of Information, Decision, Control and Memory2012Ingår i: Proc. Unsolved Problems of Noise (UPoN)Artikel i tidskrift (Refereegranskat)
  • 315. Kish, L.-B.
    et al.
    Granqvist, C.-G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Elimination of a Second-Law Attack, and All Cable-Resistance-Based Attacks, in the Kirchhoff-Law-Johnson-Noise (KLJN) Secure Key Exchange System2014Ingår i: Entropy, ISSN 1099-4300, Vol. 16, s. 5223-5231Artikel i tidskrift (Refereegranskat)
  • 316. Kish, L.-B.
    et al.
    Granqvist, C.-G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Energy Requirements of Control: Comments on Maxwell's Demon and Szilard's Engine2011Ingår i: All the Colors of Noise: Essays in Honor of Lino Reggiani / [ed] E. Alfinito, M. Leuzzi, J.-F. Millithaler, Italy: Edizioni Munari , 2011, s. 43-50Kapitel i bok, del av antologi (Refereegranskat)
  • 317. Kish, L.-B.
    et al.
    Granqvist, C.-G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Horvath, T.
    Klappenecker, A.
    Wen, H.
    Bezrukov, S.-M.
    Bird's Eye View on Noise-Based Logic2014Ingår i: International Journal of Modern Physics: Conference Series, ISSN 2010-1945, Vol. 33, nr 1460363, s. 1-6Artikel i tidskrift (Refereegranskat)
  • 318. Kish, L.-B.
    et al.
    Granqvist, C.-G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Khatri, S.-P.
    "Demonic" Challenge: Landauer's Erasure-Dissipation2014Konferensbidrag (Refereegranskat)
  • 319. Kish, L.-B.
    et al.
    Granqvist, C.-G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Khatri, S.-P.
    Wen, H.
    Demons: Maxwell's Demon, Szilard's Engine and  Landauer's Erasure-Dissipation2014Ingår i: International Journal of Modern Physics: Conference Series, ISSN 2010-1945, Vol. 33, nr 1460364, s. 1-6Artikel i tidskrift (Refereegranskat)
  • 320. Kish, L.B.
    et al.
    Granqvist, Claes Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Maxwell Demon and Szilard Engine: A full System Approach2013Konferensbidrag (Refereegranskat)
  • 321. Kish, L.B.
    et al.
    Li, Y.
    Solis, J.L.
    Marlow, W.H.
    Vajtai, R.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. fasta tillståndets fysik.
    Lantto, V.
    Smulko, J.M.
    Schmera, G.
    Detecting Harmful Gases Using Fluctuation-Enhanced Taguchi Sensors2004Ingår i: IEEE SensorsArtikel i tidskrift (Refereegranskat)
  • 322.
    Klaus-Joerger, Tanja
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för materialvetenskap.
    Joerger, Ralph
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Olsson, Eva
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Granqvist, Claes Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Bacteria as workers in the living factory: metal-accumulating bacteria and their potential for materials science2001Ingår i: Trends in Biotechnology, ISSN 0167-7799, E-ISSN 1879-3096, Vol. 19, nr 1, s. 15-20Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Metal micro-/nano-particles with suitable chemical modification can be organized into new ceramic–metal (cermet) or organic–metal (orgmet) composites or structured materials. These materials are attracting significant attention because of their unique structures and highly optimized properties. However, the synthesis of composite materials with inhomogeneities on the nanometer or sub-micrometer scale is a continuing challenge in materials science. Many industrial physical and chemical surface-coating processes using conventional techniques are both energy and cost inefficient and require sophisticated instrumentation. In the future, biology might offer a superior option.

  • 323.
    Kopniczky, J.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Hoel, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Mechler, A.
    Heszler, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Gas Deposited WO3 Nanoparticles Studied by Atomic Force Microscopy2004Ingår i: Proc SPIE 5472, 2004, s. 183-190Konferensbidrag (Refereegranskat)
  • 324. Kwan, C
    et al.
    Schmera, G
    Smulko, J
    Kish, L B
    Heszler, P
    Granqvist, Claes G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Advanced Agent Identifikation at Fluctuations-Enhanced Sensing2007Konferensbidrag (Refereegranskat)
  • 325. Kwan, Chiman
    et al.
    Schmera, Gabor
    Smulko, Janusz M.
    Kish, Laszlo B.
    Heszler, Peter
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Advanced agent identification with fluctuation-enhanced sensing2008Ingår i: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 8, nr 5-6, s. 706-713Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Conventional agent sensing methods normally use the steady state sensor values for agent classification. Many sensing elements (Hines et al., 1999, Ryan et al., 2004, Young et al.,, 2003, Qian et al., 2004, Qian et al.,, 2006, Carmel et ad., 2003) are needed in order to correctly classify multiple agents in mixtures. Fluctuation-enhanced sensing (FES) looks beyond the steady-state values and extracts agent information from spectra and bispectra. As a result, it is possible to use a single sensor to perform multiple agent classification. This paper summarizes the application of some advanced algorithms that can classify and estimate concentrations of different chemical agents. Our tool involves two steps. First, spectral and bispectral features will be extracted from the sensor signals. The features contain unique agent characteristics. Second, the features are fed into a hyperspectral signal processing algorithm for agent, classification and concentration estimation. The basic idea here is to use the spectral/bispectral shape information to perform agent classification. Extensive simulations have been performed by using simulated nanosensor data, as well as actual experimental data using commercial sensor (Taguchi). It was observed that our algorithms are able to accurately classify different agents, and also can estimate the concentration of the agents. Bispectra contain more information than spectra at the expense of high-computational costs. Specific nanostructured sensor model data yielded excellent performance because the agent responses are additive with this type of sensor. Moreover, for measured conventional sensor outputs, our algorithms also showed reasonable performance in terms of agent classification.

  • 326.
    Laaksonen, Katri
    et al.
    Aalto University.
    Li, Shu-Yi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Puisto, S. R.
    MatOx Oy.
    Rostedt, N. K. J.
    MatOx Oy.
    Ala-Nissila, T.
    Aalto University.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nieminen, R. M.
    Aalto University.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nanoparticles of TiO2 and VO2 in dielectric media: Conditions for low optical scattering, and comparison between effective medium and four-flux theories2014Ingår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 130, nr SI, s. 132-137Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Spectral transmittance and reflectance in the 300 to 2500 nm solar-optical wavelength range were calculated for nanoparticles of titanium dioxide and vanadium dioxide with radii between 5 and 100 nm embedded in transparent dielectric media. Both of the materials are of large importance in green nanotechnologies: thus TiO2 is a photocatalyst that can be applied as a porous film or a nanoparticle composite on indoor or outdoor surfaces for environmental remediation, and VO2 is a thermochromic material with applications to energy-efficient fenestration. The optical properties, including scattering, of the nanoparticle composites were computed from the Maxwell–Garnett effective-medium theory as well as from a four-flux radiative transfer model. Predictions from these theories approach one another in the limit of small particles and in the absence of optical interference. Effects of light scattering can be modeled only by the four-flux theory, though. We found that nanoparticle radii should be less than ~20 nm in order to avoid pronounced light scattering.

    Ladda ner fulltext (pdf)
    fulltext
  • 327. Lampert, C M
    et al.
    Chimshock, R
    Granqvist, Claes G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Szyszka, B
    Krebs, F
    Smart Materials Symposium2006Övrigt (Övrigt vetenskapligt)
  • 328. Lampert, C M
    et al.
    Shimshock, R
    Granqvist, Claes G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Szysza, B
    Krebs, F
    Smart Materials2007Konferensbidrag (Refereegranskat)
  • 329. Lampert, C M
    et al.
    Shimshock, R
    Granqvist, Claes G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Szyszka, B
    Krebs, F
    Smart Materials Symposium2007Konferensbidrag (Refereegranskat)
  • 330. Lampert, C M
    et al.
    Shimshock, R
    Granqvist, Claes G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Szyszka, B
    Krebs, F
    Hichwa, B
    Stevenson, I
    Andreasen, M
    Struempfel, J
    Power Generation and Energy Conversion2007Konferensbidrag (Refereegranskat)
  • 331. Lampert, C M
    et al.
    Shimshock, R
    Granqvist, Claes G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Szyszka, B
    Krebs, F
    Hichwa, B
    Stevenson, I
    Andreasen, M
    Stuempfel, J
    Hot Topic Session: Photovoltaic/Power Generation and Energy Conversion2007Konferensbidrag (Refereegranskat)
  • 332. Lampert, Carl M
    et al.
    Shimshock, Ric
    Granqvist, CG
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Diehl, Wolfgang
    Sittinger, Volker
    Sanchez, David
    Andreasen, Michael
    Coatings for energy conversion and related processes2015Ingår i: SVC Bulletin, Summer 2015, 2015Konferensbidrag (Refereegranskat)
  • 333.
    Landström, Lars
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. oorganisk kemi.
    Elihn, K
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. oorganisk kemi.
    Boman, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. oorganisk kemi.
    Granqvist, C
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Heszler, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Analysis of thermal radiation from laser-heated nanoparticles formed by laser-induced decomposition of ferrocene2005Ingår i: Applied Physics A, ISSN 1432-0630, Vol. 81, s. 827-833Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermal radiation, originating from laser-heated gas-phase nanoparticles, was detected in the 400–700 nm wavelength range by means of optical emission spectroscopy. The particles were formed upon laser-induced photolytic decomposition of ferrocene (Fe(C5H5)2) and consisted of an iron core surrounded by a carbon shell. The laser-induced excitation was performed as the particles were still within the reactor zone, and the temperature of the particles could be determined from thermal emission. Both the temperature of the nanoparticles and the relative intensity changes of the emission were monitored as a function of time (with respect to the laser pulse), laser fluence and Ar ambient pressure. At high laser fluences, the particles reached high temperatures, and evidence was found for boiling of iron. Modeling of possible energy-releasing mechanisms such as black-body radiation, thermionic electron emission, evaporation and heat transfer by the ambient gas was also performed. The dominant cooling mechanisms at different ranges of temperature were clarified, together with a determination of the accommodation factor for the Ar–nanoparticle collisions. The strong evaporation at elevated temperatures also led to significant iron loss from the produced particles.

  • 334.
    Lansåker, P. C.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Johansson, M.
    Granqvist, C.-G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Temperature Dependent Coalescence in Au Films and Nanopartickles: Applications to Smart Windows and Photocatalysis2011Konferensbidrag (Refereegranskat)
  • 335.
    Lansåker, Pia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Backholm, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    TiO2/Au/TiO2 Multilayer Thin Films: Novel Metal-Based Transparent Conductors for Electrochromic Devises2009Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 518, nr 4, s. 1225-1229Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transparent conductors based on Au films, with thicknesses in the 2.6<d<9.8 nm range, were made by DC magnetron sputtering onto glass. The films went from an "island" structure at low thicknesses to a uniform structure at d>8 nm, as seen from electron microscopy, electrical resistance, and spectrophotometric transmittance and reflectance. Optical data for uniform films were given a consistent interpretation within the Drude model. Optimized TiO2/Au/TiO2 films, with a luminous transmittance of 80%, were found to have good electrochemical durability and may be useful for applications in electrochromic devices.

  • 336.
    Lansåker, Pia C.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Gunnarsson, Klas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Roos, Arne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Au-Based Transparent Conductors for Window Applications: Effect of Substrate Material2010Ingår i: Advances in Science and Technology, ISSN 1662-0356, Vol. 75, s. 25-30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thin films of Au were made by sputter deposition onto glass substrates with and without transparent and electrically conducting layers of SnO2:In. The Au films were up to ~11 nm in thickness and covered the range for thin film growth from discrete islands, via large scale coalescence and formation of a meandering conducting network, to the formation of a more or less “holey” film. Scanning electron microscopy and atomic force microscopy showed that the SnO2:In films were considerably rougher than the glass itself. This roughness influenced the Au film formation so that large scale coalescence set in at a somewhat larger thickness for films on SnO2:In than on glass. Measurements of spectral optical transmittance and electrical resistance could be reconciled with impeded Au film formation on the SnO2:In layer, leading to pronounced “plateaus” in the near infrared optical properties for Au films on SnO2:In and an accompanying change from such two-layer films having a lower resistance than the single gold film at thicknesses below large scale coalescence to the opposite behavior for larger film thicknesses.

  • 337.
    Lansåker, Pia C
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Gunnarsson, Klas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Roos, Arne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Au thin films deposited on SnO2:In and glass: Substrate effects on the optical and electrical properties2011Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 519, nr 6, s. 1930-1933Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on a detailed study on the optical and electrical properties of Au films made by sputter deposition onto glass substrates with and without transparent and electrically conducting layers of SnO2:In. The Au films had thicknesses up to 10.7 nm and hence spanned the range for thin film growth from discrete islands, via large scale coalescence and formation of a meandering conducting network, to the formation of a more or less "holey" film. Scanning electron microscopy and atomic force microscopy demonstrated that the SnO2:In films were considerably rougher than the glass itself, and this roughness influenced the Au film formation so that large scale coalescence set in at a somewhat larger thickness for films on SnO2:In than on glass. Measurements of spectral optical transmittance and reflectance and of electrical resistance gave a fully consistent picture that could be reconciled with impeded Au film formation on the SnO2:In layer; this led to pronounced "plateaus" in the near infrared optical spectra for Au films on SnO2:In and a concomitant change from such two-layer films having a lower resistance than the single gold film at thicknesses below large scale coalescence to the opposite behavior for larger film thicknesses. Our work highlights the importance of the substrate roughness for transparent conductors comprising coinage metal films backed by wide band gap transparent conducting oxides.

  • 338.
    Lansåker, Pia C
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Hallén, Anders
    Royal Institute of Technology, Stockholm.
    Niklasson, Gunnar A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Characterization of gold nanoparticle films: Rutherford backscatteringspectroscopy, scanning electron microscopy with image analysis, and atomic forcemicroscopy2014Ingår i: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 4, nr 10, s. 107101-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gold nanoparticle films are of interest in several branches of science and technology,and accurate sample characterization is needed but technically demanding. We preparedsuch films by DC magnetron sputtering and recorded their mass thicknessby Rutherford backscattering spectroscopy. The geometric thickness dg—from thesubstrate to the tops of the nanoparticles—was obtained by scanning electron microscopy(SEM) combined with image analysis as well as by atomic force microscopy(AFM). The various techniques yielded an internally consistent characterization ofthe films. In particular, very similar results for dg were obtained by SEM with imageanalysis and by AFM.

    Ladda ner fulltext (pdf)
    fulltext
  • 339.
    Lansåker, Pia C
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Thin gold films on SnO2:In: Temperature-dependent effects on the optical properties2012Ingår i: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 520, nr 9, s. 3688-3691Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gold films with thicknesses of 5 +/- 0.5 nm were sputter deposited onto SnO2:In-coated glass kept at different temperatures up to 140 degrees C, and similar films, deposited onto substrates at 25 degrees C, were annealing post treated at the same temperatures. Nanostructures and optical properties were recorded by scanning electron microscopy and spectrophotometry in the 0.3 to 2.5 mu m wavelength range, respectively. Annealing had a minor influence on the optical transmittance despite significant changes in the scale of the nanostructure, whereas deposition onto substrates heated to 140 degrees C yielded granular films with strong plasmon absorption of luminous radiation. These results are of considerable interest for optical devices with gold films prepared at elevated temperature or operating at such temperature.

  • 340.
    Lansåker, Pia C.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Petersson, P.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandemlaboratoriet.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Thin sputter deposited gold films on In2O3:Sn, SnO2:In, TiO2 and glass: Optical, electrical and structural effects2013Ingår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 117, nr SI, s. 462-470Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thin gold films are promising transparent conductors with many actual and potential uses in "green" technologies, transparent electronics, etc. These applications require different substrate materials, and hence it is important to understand the role of the substrate on Au thin film growth. Such effects have been studied in this work wherein Au films ranging from island structures, via large scale coalescence into meandering metal networks, to thin homogenous layers were deposited by DC magnetron sputtering onto glass substrates and In2O3:Sn (ITO), SnO2:In and TiO2 base layers backed by glass. Optical, electrical and structural properties were recorded for films deposited onto unheated substrates. We found distinct and characteristic differences in Au growth on the various backings. Thus ITO and SnO2:In base layers yielded gold films with island features remaining to larger thicknesses than for deposition directly onto glass, and the sheet resistance was lower for gold deposition onto SnO2:In and ITO only when the gold films were less than similar to 5 nm in thickness. Our results highlight the complexity of substrates' influence on thin film formation. 

  • 341.
    Lansåker, Pia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Cindemir, Umut
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Österlund, Lars
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Indium Tin Oxide Thin Films for Formaldehyde and Acetaldehyde Sensing2014Ingår i: Micronano System Workshop, Uppsala, Sweden, 15-16 May, 2014Konferensbidrag (Refereegranskat)
  • 342.
    Lansåker, Pia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Au-based Transparent Conductors with Electrochemical Stability2009Ingår i: Advances in Transparent Electronics: From Materials to Devices, 2009Konferensbidrag (Refereegranskat)
  • 343.
    Lansåker, Pia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Gunnarsson, Klas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Mikrosystemteknik.
    Roos, Arne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, C.-G.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Au-based transparent conductors for windows applications: Effect of substrate material2010Ingår i: International Journal of Advances in Science and Technology, ISSN 2229-5216, Vol. 75, s. 25-30Artikel i tidskrift (Refereegranskat)
  • 344.
    Lansåker, Pia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Ribbing, Carl-Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Temperature effect on gold nanoparticle growth and plasmonic properties.2013Ingår i: Optics and Photonics in Sweden, Uppsala Oct. 22-23, 2013: Poster abstracts, PhotonicSweden , 2013, s. 1 p-Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The plasmonic properties of gold nanoparticles (NPs) have very promising prospects to enhance theefficiency in several branches of science and technology, such as in environmental, energy, biomedicaland information technology. The plasmonic properties are strongly related to the shape, size anddistribution of the NPs and to their surrounding media. Therefore, suitable techniques for optimizedNP manufacturing, as well as improved understanding of the optical characteristics of the NPs, arenecessary for progress.In this work, gold was deposited on heated substrates using DC magnetron sputtering, which is amethod with great reproducibility and suitability for large area coatings. The method is also simple touse and gives NPs at considerably lower temperatures than other heat treating manufacturingtechniques. The depositions were performed at three different substrate temperatures, and a series ofgold NP samples were manufactured at each temperature. The localized surface plasmon resonance ofthe NPs was investigated by optical measurements, and the results were related to the shape, size anddistribution of the NPs, as observed from scanning electron microscopy and image analysis. Basic physics regarding plasmonics and metal NP growth processes are also presented.The optical results show effects of particle-particle interaction, aspect ratio and size of the NPs,which are in full agreement with results on NP structure and distribution.

  • 345.
    Lansåker, Pia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Tuncer, Enis
    3M Austin Center, EEBG/CRML, Austin, Texas, USA.
    Valyukh, Irina
    Dept. Physics, Chemistry and Biology, Linköping University.
    Arwin, Hans
    Dept. Physics, Chemistry and Biology, Linköping University.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Spectral Density Analysis of Thin Gold Films: Thickness and Structure Dependence of the Optical Properties2013Ingår i: PIERS 2013 Stockholm: Progress in Electromagnetics Research Symposium Proceedings,, Cambridge, MA: The Electromagnetics Academy , 2013, s. 443-447Konferensbidrag (Refereegranskat)
    Abstract [en]

    Abstract| In this paper we study the feasibility of representing the optical properties ofultrathin gold films by effective medium theories. Gold films with mass thicknesses in the range of 1.4 to 9.2 nm were deposited by DC magnetron sputtering onto non-heated glass substrates.Optical measurements in the range 0.25 to 2 μm were carried out by spectroscopic ellipsometry, and the effective complex dielectric function of each film was determined. The gold films were modelled as a mixture of gold and air, and a general effective medium description using the spectral density function (SDF) was used to describe their optical properties. Numerical inversion of the experimental dielectric function gave a broad and rather featureless SDF, with a few superimposed peaks, both for island structures and percolating films. The broad background is qualitatively similar to predictions of the Bruggeman model [14].

  • 346. Laszlo, Kish
    et al.
    Schemera, G
    Ling, M D
    Cheng, M
    Young, R
    Granqvist, Claes G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Berger, A
    Fluctuation-Enhanced Chemical/Biological Sensing and Prompt Identification of Bacteria by Sensing of Phage-Triggered Ion Cascade (SEPTIC)2006Ingår i: Proc. International Symposium on Spectral Sensing Research, 2006, s. 2-Konferensbidrag (Övrigt vetenskapligt)
  • 347.
    Lentka, Lukasz
    et al.
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, Narutowicza 11-12, PL-80233 Gdansk, Poland.
    Kotarski, Mateusz
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, Narutowicza 11-12, PL-80233 Gdansk, Poland.
    Smulko, Janusz
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, Narutowicza 11-12, PL-80233 Gdansk, Poland.
    Cindemir, Umut
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Topalian, Zareh
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Calavia, Raul
    Rovira & Virgily Univ, Dept Elect, Tarragona 43006, Spain.
    Ionescu, Radu
    Rovira & Virgily Univ, Dept Elect, Tarragona 43006, Spain.
    Fluctuation-enhanced sensing with organically functionalized gold nanoparticle gas sensors targeting biomedical applications2016Ingår i: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 160, s. 9-14Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Detection of volatile organic compounds is a useful approach to non-invasive diagnosis of diseases through breath analysis. Our experimental study presents a newly developed prototype gas sensor, based on organically-functionalized gold nanoparticles, and results on formaldehyde detection using fluctuation-enhanced gas sensing. Formaldehyde was easily detected via intense fluctuations of the gas sensor's resistance, while the cross-influence of ethanol vapor (a confounding factor in exhaled breath, related to alcohol consumption) was negligible.

    Ladda ner fulltext (pdf)
    fulltext
  • 348.
    Lentka, Lukasz
    et al.
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, Narutowicza 11-12, PL-80233 Gdansk, Poland..
    Smulko, Janusz
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, Narutowicza 11-12, PL-80233 Gdansk, Poland..
    Kotarski, Mateusz
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, Narutowicza 11-12, PL-80233 Gdansk, Poland..
    Granqvist, Claes Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Ionescu, Radu
    Univ Rovira & Virgili, ETSE DEEEA, Dept Elect, Tarragona 43003, Spain..
    Non-Gaussian Resistance Fluctuations in Gold-Nanoparticle-Based Gas Sensors: An Appraisal of Different Evaluation Techniques2017Ingår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, nr 4, artikel-id 757Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Volatile organic compounds, such as formaldehyde, can be used as biomarkers in human exhaled breath in order to non-invasively detect various diseases, and the same compounds are of much interest also in the context of environmental monitoring and protection. Here, we report on a recently-developed gas sensor, based on surface-functionalized gold nanoparticles, which is able to generate voltage noise with a distinctly non-Gaussian component upon exposure to formaldehyde with concentrations on the ppm level, whereas this component is absent, or at least much weaker, when the sensor is exposed to ethanol or to pure air. We survey four different statistical methods to elucidate a non-Gaussian component and assess their pros and cons with regard to efficient gas detection. Specifically, the non-Gaussian component was clearly exposed in analysis using level-crossing parameters, which require nothing but a modest computational effort and simple electronic circuitry, and analogous results could be reached through the bispectrum function, albeit with more intense computation. Useful information could be obtained also via the Levy-stable distribution and, possibly, the second spectrum.

    Ladda ner fulltext (pdf)
    fulltext
  • 349.
    Lentka, Lukasz
    et al.
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, PL-80233 Gdansk, Poland..
    Smulko, Janusz M.
    Gdansk Univ Technol, Fac Elect Telecommun & Informat, PL-80233 Gdansk, Poland..
    Ionescu, Radu
    Univ Rovira & Virgili, ETSE DEEEA, Dept Elect, Tarragona 43003, Spain..
    Granqvist, Claes Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kish, Laszlo B.
    Texas A&M Univ, Dept Elect & Comp Engn, College Stn, TX 77843 USA..
    DETERMINATION OF GAS MIXTURE COMPONENTS USING FLUCTUATION ENHANCED SENSING AND THE LS-SVM REGRESSION ALGORITHM2015Ingår i: METROLOGY AND MEASUREMENT SYSTEMS, ISSN 0860-8229, Vol. XXII, nr 3, s. 341-350Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper analyses the effectiveness of determining gas concentrations by using a prototype WO3 resistive gas sensor together with fluctuation enhanced sensing. We have earlier demonstrated that this method can determine the composition of a gas mixture by using only a single sensor. In the present study, we apply Least-Squares Support-Vector-Machine-based (LS-SVM-based) nonlinear regression to determine the gas concentration of each constituent in a mixture. We confirmed that the accuracy of the estimated gas concentration could be significantly improved by applying temperature change and ultraviolet irradiation of the WO3 layer. Fluctuation-enhanced sensing allowed us to predict the concentration of both component gases.

    Ladda ner fulltext (pdf)
    fulltext
  • 350.
    Li, Shuyi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Bayrak Pehlivan, Ilknur
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Niklasson, Gunnar A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Granqvist, Claes-Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Progress in Electrochromics and Thermochromics: Two New Applications Involving ITO Nanoparticles.2012Ingår i: Society of Vacuum Coaters 55th Annual Technical Conference Proceedings, Albuquerque, USA: Soiety of Vacuum Coaters , 2012, s. 41-46Konferensbidrag (Refereegranskat)
45678910 301 - 350 av 534
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf