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  • 2001.
    Zhao, Shuxi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Avendano, Esteban
    Gelin, Kristina
    Lu, Jun
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Optimization of an industrial DC magnetron sputtering process for graded composition solar thermal absorbing layer2006Ingår i: Solar Energy Materials & Solar Cells, ISSN 0927-0248, Vol. 90, nr 3, s. 308-328Artikel i tidskrift (Refereegranskat)
  • 2002.
    Zhao, Shuxi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Ribbing, C G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Coating a Reststrahlen Material for Selective Emisson2007Konferensbidrag (Refereegranskat)
  • 2003.
    Zhao, Shuxi
    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.
    Reactively sputtered aluminium nitride films for spectral emission control2008Ingår i: Proceedings / [ed] Norbert Kaiser, Michel Lequime, H Angus Macleod, 2008, s. 71011F-Konferensbidrag (Refereegranskat)
  • 2004.
    Zhao, Shuxi
    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.
    Options for Reststrahlen Materials in Optical Surfaces and Filters2010Ingår i: Chinese Optics Letters, ISSN 1671-7694, Vol. 8, nr Supplement 1, s. 119-124Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The current potential applications of reststrahlen bands in optical surfaces and components are reviewed. This type of interval with metallic-like high reflectance has been used for monochromatization in infrared and when wavelength selective low emittance is needed for frost prevention or infrared signature reduction. Associated features, including a narrow reflectance minimum for a wide range of angles of incidence, are potentially useful.

  • 2005.
    Zhao, Shuxi
    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.
    Ribbing, Carl-Gustaf
    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.
    Wäckelgård, Ewa
    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.
    New method to optimize a solar absorber graded film profile2004Ingår i: Solar Energy, Vol. 77Artikel i tidskrift (Refereegranskat)
  • 2006.
    Zhao, Shuxi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Ribbing, C-G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Options for Reststrahlen Materials in Optical Surfaces and Filters2009Konferensbidrag (Refereegranskat)
  • 2007.
    Zhao, Shuxi
    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.
    Ribbing, C-G
    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.
    Wäckelgård, Ewa
    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.
    Optical constants of sputtered Ni/NiO solar absorber films –depth profile characterization2004Ingår i: Solar Energy Materials and Solar Cells, Vol. 84, s. 193-203Artikel i tidskrift (Refereegranskat)
  • 2008.
    Zhao, Shuxi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Gradient Coatings by Moving Substrate for Large Scale Production2010Konferensbidrag (Refereegranskat)
  • 2009.
    Zhao, Shuxi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Optimization of solar absorbing three-layer coatings2006Ingår i: Solar Energy Materials & Solar Cells, ISSN 0927-0248, Vol. 90, nr 3, s. 243-261Artikel i tidskrift (Refereegranskat)
  • 2010.
    Zhao, Shuxi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Optimization of solar absorbing three-layer coatings2006Ingår i: Solar Energy Materials & Solar Cells, nr 90, s. 243-261Artikel i tidskrift (Refereegranskat)
  • 2011.
    Zhao, Shuxi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    The optical properties of sputtered composite of Al-AlN2006Ingår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 90, nr 13, s. 1861-1874Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Optical constants n and k have been determined for aluminum-aluminum nitride composite in a reactive gas flow from zero to a flow giving stoichiometric nitride. A method using a dielectric function model was applied for each component in the Bruggeman equation to fit the experimental reflectance and transmittance spectra in the wavelength range of 0.3-2.5 mu m. The refractive index of aluminum-aluminum nitride showed a maximum as the reactive gas increased. The extinction coefficient, on the other hand, decreased with increased reactive gas flow. The determined optical properties were then used to design a multilayer selective surface for solar thermal applications. Two absorbing layers with a graded feature plus an anti-reflection layer resulted in a high calculated solar absorptance of 0.97. The optimized metal content corresponds to the composite around the maximum refractive index. A solar absorptance of 0.96 was reached for experimentally prepared surfaces according to the theoretical prediction.

  • 2012.
    Zhao, Shuxi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Zhu, Decchun
    Hefei University 230022, Hefei, PR. China.
    Ribbing, Carl-Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Angular dependence of coloured absorber coatings2012Ingår i: The International Conference on Optical Thin Films and Coating Technology, 15-18 October 2012, Hangzhou, China: Frontiers of Optical Coatings / [ed] Weidong Shen, 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Angular dependence of coloured absorber coatings

    Shuxi Zhao1, Dechun Zhu2 and Carl-G.Ribbing1

     

    1) Div. of Solid State Physics, Ångström Laboratory, Uppsala University

         Box 534, SE-751 21 Uppsala, Sweden

    2) Dept. of Chemical and Materials Engineering, Hefei University

         230022, Hefei, PR. China

     

    Abstract

    Investigations of angular dependence of thermal solar absorber coatings have been carried out in the Uppsala SSP-division since more than 10 years. In this contribution the angular variation of the optical properties of the recently suggested TiAlN-based coloured absorber is reported.

      The presence of an interference controlled colour raises a concern that strong irradiscence might make the roof integration of such absorbers aesthetically unsuitable. Using colour coordinates calculated from the measured reflectance spectra we reach the conclusion that the attractive colour seen in normal incidence is only marginally changed by the natural change of angle of incidence for a stationary collector.

      A second issue to be considered is whether this new absorber surface performs better or worse than earlier cermet absorbers when the solar incidence angle varies. The reflectance of TiAlN, as well as the antireflected TiAlON, as a function of wavelength and angle of incidence has therefore been measured using an integrating sphere with a rotatable sample holder in the centre. For comparison and calibration such measurements, such measurement was also carried out on a freshly sputtered, opaque gold film. The angular variation was fitted using the Incident Angle Modifier Kta, the ratio of the measured absorptance for incidence angle, to that at normal incidence:

    Abstract

    Investigations of angular dependence of thermal solar absorber coatings have been carried out in the Uppsala SSP-division since more than 10 years. In this contribution the angular variation of the optical properties of the recently suggested TiAlN-based coloured absorber is reported.

      The presence of an interference controlled colour raises a concern that strong irradiscence might make the roof integration of such absorbers aesthetically unsuitable. Using colour coordinates calculated from the measured reflectance spectra we reach the conclusion that the attractive colour seen in normal incidence is only marginally changed by the natural change of angle of incidence for a stationary collector.

  • 2013.
    Zhao, Shuxi
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Zhu, Dechun
    Department of Chemical and Materials Engineering, Hefei University, China.
    Ribbing, Carl-Gustaf
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Colour control and selectivity in TiAlN solar-thermal absorbers2011Ingår i: Advances in Optical Thin Films IV. Optical Systems Design 2011, 5 September 2011, Marseille, France, / [ed] Michel Lequime, H. Angus Macleod, Detlev Ristau, Washington: SPIE - International Society for Optical Engineering, 2011, s. 81680G-1-81680G-9Konferensbidrag (Refereegranskat)
    Abstract [en]

    Optical constants for simulations were obtained by R- and T-measurements on TiAlN thin films deposited on Corning 7059 glass. The model parameterized free carrier effects and an inter-band excitation. The calculations demonstrated that the colour effects are due to interference and inter-band absorption around 500 nm in a single layer coating. The peak shifts with the thickness of the thin film which gives a simple way to obtain different colours. Solar absorptance of 86 % can be reached already for a single TiAlN-film on an Al substrate.

  • 2014. Zheng, Liqing
    et al.
    Gao, Fangyuan
    Zhao, Shuxi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Zhou, Fuyun
    Nshimiyimana, Jean Pierre
    Diao, Xungang
    Optical design and co-sputtering preparation of high performance Mo-SiO2 cermet solar selective absorbing coating2013Ingår i: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 280, s. 240-246Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to optimize and prepare high performance Mo-SiO2 cermet solar selective absorbing coating, a series of Mo-SiO2 cermet films with different metal volume fraction were deposited on optical glass using mid-frequency (MF) and radio frequency (RF) co-sputtering. The reflectance (R) and transmittance (T) in the wavelength range of 250-2500 nm have been simulated using SCOUT software with different dielectric function models. The optical constants, film thickness, metal volume fraction and other parameters have been deduced from the modeling. The fitted optical constants were then used to simulate and optimize the Mo-SiO2 solar selective coating and samples were prepared based on the optimized parameters. The Maxwell Garnett (MG) and Bruggeman (BR) effective-medium theory have been added in the dielectric function models to describe low metal volume fraction cermet layer (LMVF) and high metal volume fraction cermet layer (HMVF), separately. The optical spectra (R and T) of all single films were in a good agreement with the fitted spectra by dielectric function models. The experimental measured reflectance of the solar selective coating was also in rather good agreement with the optimized result. The solar absorptance of theoretically optimized selective coating was 0.945, while the absorptance of the experimental coating was 0.95. The thermal emittance of 0.15 (at 400 degrees C) was obtained. 

  • 2015.
    Zhu, Dechun
    et al.
    Department of Chemical and Materials Engineering, Hefei University, China.
    Mao, Fang
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Zhao, Shuxi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    The influence of oxygen in TiAlOxNy on the optical properties of colored solar-absorbing coatings2012Ingår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 98, s. 179-184Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Low cost and ease of fabrication are important factors for solar-thermal applications in energy-efficient buildings. This contribution reports the influence of oxygen on structure, optical properties and chromaticity of TiAlOxNy thin films prepared by DC magnetron sputtering. It is an extension of a previous study on colored solar-thermal absorbers based on titanium-aluminum nitride. The purpose is to investigate the possibility of using TiAlOxNy as middle layer to achieve a gradient effect. The results reveal that the structure and optical properties of the TiAlOxNy coatings are sensitive to the oxygen content under certain sputtering conditions.  The ratio of oxygen/nitrogen of 0.7:10 is the most appropriate to form the crystalline structure of TiAlON.  The optical constants of TiAlN and TiAlON were deduced by fitting the experimental data. It shows that both the refractive index (n) and the extinction coefficient (k) are decreased when oxygen is introduced to form titanium-aluminium nitro-oxide. The gradient effect can be achieved and controlled by adjusting the ratio of oxygen/nitrogen flow during the process to enhance solar absorptance while keeping the desired color appearance.

  • 2016.
    Zhu, Dechun
    et al.
    Department of Chemical and Materials Engineering, Hefei University, China.
    Zhao, Shuxi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Chromaticity and Optical Properties of Colored and Black Solar-Thermal Absorbing Coatings2010Ingår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 94, nr 10, s. 1630-1635Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two important trends in solar thermal utilization in buildings are building integration and color appearance. Coatings based on titanium alloy nitride show variety of different colors. These can be controlled by film thickness for a single layer stack, or by putting another layer on top of the first layer. Strong absorption around 500 nm is important to cause color appearance. Chromaticity and optical properties of colored coatings were studied and compared to black coatings. In the three-point gamut system, such colors show an additive mixture property. Solar absorptance of 0.80 to 0.95 can be obtained with thermal emittance of 0.04 to 0.09 (100oC). These coatings provide a choice for solar thermal integration in buildings where appearance is an important feature.

  • 2017.
    Zhu, Dechun
    et al.
    Hefei University, China.
    Zhao, Shuxi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Optical Properties of Colored Solar-Thermal Absorbing Coatings2009Konferensbidrag (Refereegranskat)
  • 2018.
    Åberg, Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Investigating the impact of heat demand reductions on Swedish district heating production using a set of typical system models2014Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 118, s. 246-257Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The European Union (EU) aims at reducing its CO2 emissions and use of primary energy. The EU also aims to improve the energy efficiency in buildings and promote the use of combined heat and power (CHP) plants in district heating (DH) systems. Due to significant differences among DH systems regarding fuel use and heat production units, results for one individual DH systems are not generally valid for other DH systems. Therefore, there is a need to generally describe entire DH sectors in a way that considers the heat production plant merit-orders of the individual DH systems. Here, four models of typical DH systems are defined to represent the Swedish DH sector. A scenario for stepwise heat demand reductions due to building energy efficiency improvements is studied. The results show that heat demand reductions in Swedish DH systems generally reduce global CO2 emissions and mainly reduce the use of biomass and fossil fuels, while the use of waste and industrial waste heat (IWH) is less influenced. The results further show that in order to maximise the reduction of CO2 emissions by energy conservation in buildings, the heat production technologies of the DH system should be considered. A large share of CHP production with a high electricity-to-heat output ratio decreases the possibilities to reduce global CO2 emissions through heat demand reductions.

  • 2019.
    Åberg, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Carlsson, Jonas
    ekoPerspektiv AB.
    Nilsson, Annica M
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Improved efficiency for distribution and use of district heating: A simulation study of retrofitting a Swedish apartment complex from the 1970's2018Ingår i: Journal of Building Engineering, ISSN 2352-7102, Vol. 20, s. 559-568Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Important features of the next generation of district heating systems are low distribution heat losses and low distribution temperatures. The purpose of this transition is to compensate for reduced heat demand densities caused by increased energy efficiency in buildings. In Sweden a majority of multi-family residential buildings are connected to district heating networks that are up to 50 years old. This study investigates the possibility to improve building energy efficiency and simultaneously reduce distribution temperatures and losses for a Swedish apartment complex built in the 1970's. The results show that a combination of better insulated building envelopes and ventilation heat recovery can reduce the heat demand in the studied apartment complex by 53%. The improved building energy performance significantly reduces the required supply temperatures for space heating and reduces heat distribution losses to some extent. The heat distribution losses can be reduced further (up to 49%) by replacing central hot water preparation with apartment based heat exchangers. This eliminates heat losses from pipes for domestic hot water supply and hot water circulation. The study concludes that a potential cost-synergy occurs when a holistic strategy is adopted and conventional energy efficiency measures are combined with reduced distribution losses.

  • 2020.
    Åberg, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Fälting, Lars
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Ekonomisk-historiska institutionen.
    Carlsson, Jonas
    ekoPerspektiv.
    Johansson, Lars
    EC-Power.
    Forssell, Anders
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Företagsekonomiska institutionen.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nilsson, Annica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Munkhammar, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Lingfors, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nya lösningar för fjärrvärme i miljonprogramsområden2017Rapport (Övrigt vetenskapligt)
  • 2021.
    Åberg, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Fälting, Lars
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Ekonomisk-historiska institutionen.
    Forssell, Anders
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Företagsekonomiska institutionen.
    Is Swedish district heating operating on an integrated market?: Differences in pricing, price convergence, and marketing strategy between public and private district heating companies2016Ingår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 90, s. 222-232Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The deregulation of the Swedish electricity market in 1996 made it possible to operate municipal district heating commercially. Until that time district heating had been organised mainly as municipal utilities. After 1996 district heating is instead expected to function on a market. In competitive and integrated markets, prices are expected to be equal, or converging. To find out if district heating operates on an integrated market the differences in price levels, price convergence, price strategy, and business goals, among municipal, private and state owned district heating companies are investigated.

    Price statistics was used along with results from a questionnaire that was answered by representatives for 109 Swedish district heating companies. The results show that prices among district heating systems do not converge significantly and that variations in prices among municipal systems are larger than among private and state owned systems. Furthermore, despite the fact that district heating is supposed to be commercial, a vast majority of district heating companies apply cost-based pricing and not market pricing. The municipal companies give priority to political goals before financial goals. The conclusion is that a Swedish integrated market for heat has not yet evolved, and some district heating price-controlling mechanism is necessary.

  • 2022.
    Åberg, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Henning, D.
    Optimisation of a Swedish district heating system with reduced heat demand due to energy efficiency measures in residential buildings2011Ingår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 39, nr 12, s. 7839-7852Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development towards more energy efficient buildings, as well as the expansion of district heating (DH) networks, is generally considered to reduce environmental impact. But the combined effect of these two progressions is more controversial. A reduced heat demand (HD) due to higher energy efficiency in buildings might hamper co-production of electricity and DH. In Sweden, co-produced electricity is normally considered to displace electricity from less efficient European condensing power plants. In this study, a potential HD reduction due to energy efficiency measures in the existing building stock in the Swedish city Linkoping is calculated. The impact of HD reduction on heat and electricity production in the Linkoping DH system is investigated by using the energy system optimisation model MODEST. Energy efficiency measures in buildings reduce seasonal HD variations. Model results show that HD reductions primarily decrease heat-only production. The electricity-to-heat output ratio for the system is increased for HD reductions up to 30%. Local and global CO(2) emissions are reduced. If co-produced electricity replaces electricity from coal-fired condensing power plants, a 20% HD reduction is optimal for decreasing global CO(2) emissions in the analysed DH system.

  • 2023.
    Åberg, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Molin, Andreas
    IEI, Linköping Universitet.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Moshfegh, Bahram
    IEI, Linköpings universitet.
    Greenhouse Gas Emission from General District Heat use in Sweden: An Approach for Justified Comparisons in Residential Energy Use2008Konferensbidrag (Refereegranskat)
  • 2024.
    Åberg, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nilsson, Annica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Munkhammar, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Luthander, Rasmus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Lingfors, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Electricity self-sufficiency and primary energy use in a Swedish residential community, after building renovation and implementation of photovoltaics, small-scale CHP, and electric vehicles2016Ingår i: Proceedings of the 2016 ACEEE Summer Study on Energy Efficiency in Buildings, Pacific Grove, CA, USA, August 21-26, 2016, 2016Konferensbidrag (Refereegranskat)
  • 2025.
    Åberg, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Development, validation and application of a fixed district heating model structure that requires small amounts of input data2013Ingår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 75, s. 74-85Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reducing the energy use of buildings is an important part in reaching the European energy efficiency targets. Consequently, local energy systems need to adapt to a lower demand for heating. A 90% of Swedish multi-family residential buildings use district heating (DH) produced in Sweden’s over 400 DH systems, which use different heat production technologies and fuels. DH system modelling results obtained until now are mostly for particular DH systems and cannot be easily generalised. Here, a fixed model structure (FMS) based on linear programming for cost-optimisaton studies of DH systems is developed requiring only general DH system information. A method for approximating heat demands based on local outdoor temperature data is also developed. A scenario is studied where the FMS is applied to six Swedish DH systems and heat demands are reduced due to energy efficiency improvements in buildings. The results show that the FMS is a useful tool for DH system optimisation studies and that building energy efficiency improvements lead to reduced use of fossil fuels and biomass in DH systems. Also, the share of CHP in the production mix is increased in five of the six DH systems when the heat demand is reduced.

  • 2026.
    Åberg, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Henning, Dag
    Optensys Energianalys, Cleantech Park, Linköping.
    Sensitivity of district heating system operation to heat demand reductions and electricity price variations: A Swedish example2012Ingår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 41, nr 1, s. 525-540Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the future, district heating companies in Sweden must adapt to energy efficiency measures in buildings and variable fuel and electricity prices. Swedish district heating demands are expected to decrease by 1-2% per year and electricity price variations seem to be more unpredictable in the future. A cost-optimisation model of a Swedish local district heating system is constructed using the optimisation modelling tool MODEST. A scenario for heat demand changes due to increased energy efficiency in buildings, combined with the addition of new buildings, is studied along with a sensitivity analysis for electricity price variations. Despite fears that heat demand reductions will decrease co-generation of clean electricity and cause increased global emissions, the results show that anticipated heat demand changes do not increase the studied system's primary energy use or global CO2 emissions. The results further indicate that the heat production plants and the fuels used within the system have crucial importance for the environmental impact of district heat use. Results also show that low seasonal variations in electricity price levels with relatively low winter prices promote the use of electric heat pumps. High winter prices on the other hand promote co-generation of heat and electricity in CHP plants.

  • 2027.
    Åberg, Magnus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Henning, Dag
    Large-scale introduction of new residential district-heating loads to increase renewable electricity generation in CHP plants2012Ingår i: Proceedings of the World Renewable Energy Forum 2012, Denver, Colorado, USA, May 13-17, 2012, 2012, s. 2407-2414Konferensbidrag (Refereegranskat)
    Abstract [en]

    Combined heat and power (CHP) plants enable an efficient use of low-grade energy carriers, such as domestic waste and biomass, for co-generation of district heating (DH) and electricity. Expected future building energy-efficiency improvements reduce the demand for space heating and may limit the possibilities to cogenerate electricity. The use of DH for new applications, such as household appliances, can improve conditions for co-generation of electricity. This paper investigates the future potential to increase DH demand and co-generation of electricity due to large-scale implementation of household appliances that use DH instead of electricity. The analysis is applied to the DH system in Uppsala, Sweden. Results show that co-generation of electricity and total fuel use increase with implementation of household appliances connected to a building hot water circuit (HWC). The impact on CO2 emissions depends on DH fuel mix and electricity assessment approach.

  • 2028.
    Ågren, Sebastian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Energieffektivisering av industribelysning: Planering av belysningsanläggning i mekanisk verkstad2012Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In Uppsala, Sweden, Vattenfall has a combined heat and power plant. On the premises there is an engineering workshop with old fluorescent and mercury lamps that need to be replaced. This provides a great opportunity to save energy and money by installing more efficient lighting. The main purpose of this study was to present two functional and energy efficient lighting systems including control system. The lighting systems were designed by investigating the working environment, measuring illuminance and by simulations in the software DIALux. Additionally Life Cycle Cost (LCC) was used as an instrument of comparison. One alternative was designed using mainly modern T5 fluorescent lighting. For the other alternative powerful LED-lamps were chosen as the primary light source. The simulations showed the two alternatives to be equally good in regard to performance and energy saving potential. With sustained illuminance level the installed power of both systems was around 34 kW ascompared to 54 kW, the estimated value of the existing lighting system. The LCC, however, differed significantly with the fluorescent alternative having a total cost of 1.1 million SEK over a 20 year period while the same number for the LED alternative being 2.2 million SEK. The difference in LCC makes fluorescent lighting the preferable alternative. The present consumption is estimated to 142 MWh. The fluorescent lighting alternative would have an approximated energy consumption of 78.6 MWh including a control system, giving an energy saving potential of 45 %.

  • 2029.
    Åkerlund, Hanna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Scenarion och potential för energieffektivisering i Uppsala kommuns bostäder fram till år 2050: Ett arbete inom Färdplan 2050 för ett klimatpositivt Uppsala2014Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Syftet med detta examensarbete är att kartlägga potentialen för energieffektiviseringar i småhus och flerbostadshus i Uppsala kommun fram till 2050. Studien inkluderar både befintliga och framtida byggnader. Uppsala kommun arbetar tillsammans med flera olika organisationer i kommunen med att ta fram en ”Färdplan för ett klimatpositivt Uppsala år 2050” (kallad Färdplan 2050), detta med uppdrag av Naturvårdsverket. Målet med Färdplan 2050 är att ta fram en långsiktsprognos för hur Uppsala kommun kan minska utsläppen av växthusgaser med 45 % per invånare till år 2020 jämfört med år 1990. Detta för att sedan nå det långsiktiga målet, ett maximalt koldioxidutsläpp på 0,5 ton per invånare senast 2050. Resultaten från examensarbetet kommer ingå i Färdplan 2050 och på så sätt ligga till grund för kommunens framtida energipolitik.

     

    I examensarbetet bestämdes tre olika framtidsscenarion: referens-, aktörs- samt ett potentialscenario. Referensscenariot beskriver en trolig utveckling av energianvändningen där en ”spontan” energieffektiviseringstakt på 0,4 % per år för småhus och 0,6 % per år för flerbostadshus antas. Aktörscenariot ska inkludera effekter av åtgärder som lokala aktörer genomför eller planerar att genomföra. För flerbostadshus innebär detta en energibesparing på 5,5 % och för småhus saknas ett riktat initiativ att göra mer än snittet i Sverige. Potentialscenariot var ämnat att baseras på energideklarationer gjorda i Uppsala kommun. Åtgärdsförslagen i energideklarationerna var tänk att ligga till grund för energieffektiviseringspotentialen. Det visade sig att åtgärdsförslagen inte var tillräckliga för att kartlägga den energieffektiviseringspotential som fanns i kommunen.

     

    För att kartlägga potentialen för energieffektiviseringar i befintliga byggnader simulerades olika energieffektiviseringsåtgärder på ett antal typhus. Simuleringsprogrammet som användes var VIP-Energy. Simuleringarna resulterade i en potential att minska energiförbrukningen i småhus med 64 % och 45 % för flerbostadshus. Potentialen för framtida byggnader beräknades till ungefär 23 % för bostäder som byggs fram till 2030 och 22 % till år 2050.

     

    Slutsatserna av arbetet är bland annat att BBR:s krav på energiförbrukning i byggnader är för låga för att nå klimatmålen. Simuleringarna av scenarion i LEAP visar att det finns en stor potential för energieffektiviseringar i Uppsala kommun. För att nå potentialen krävs dock mer energieffektiviseringsarbete, både i befintliga byggnader och för nybyggnationer.

  • 2030. Ångström, Jonas
    et al.
    Johansson, Robert
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Sarkar, Tapati
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Sorby, Magnus H.
    Inst Energy Technol, Phys Dept, NO-2027 Kjeller, Norway..
    Zlotea, Claudia
    CNRS UPEC, Inst Chim & Mat Paris Est, F-94320 Thiais, France..
    Andersson, Mikael S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nordblad, Per
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Scheicher, Ralph H.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Haussermann, Ulrich
    Stockholm Univ, Dept Mat & Environm Chem, SE-10691 Stockholm, Sweden..
    Sahlberg, Martin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Hydrogenation-Induced Structure and Property Changes in the Rare-Earth Metal Gallide NdGa: Evolution of a [GaH](2-) Polyanion Containing Peierls-like Ga-H Chains2016Ingår i: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 55, nr 1, s. 345-352Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hydride NdGaH1+x (x approximate to 0.66) and its deuterized analogue were obtained by sintering the Zintl phase NdGa with the CrB structure in a hydrogen atmosphere at pressures of 10-20 bar and temperatures near 300 degrees C. The system NdGa/NdGaH1+x exhibits reversible H storage capability. H uptake and release were investigated by kinetic absorption measurements and thermal desorption mass spectroscopy, which showed a maximum H concentration corresponding to "NdGaH2" (0.93 wt % H) and a two-step desorption process, respectively. The crystal structure of NdGaH1+x was characterized by neutron diffraction (P2(1)/m, a = 4.1103(7), b = 4.1662(7), c = 6.464(1) angstrom, beta = 108.61(1)degrees Z = 2). H incorporates in NdGa by occupying two distinct positions, H1 and H2. HI is coordinated in a tetrahedral fashion by Nd atoms. The H2 position displays flexible occupancy, and H2 atoms attain a trigonal bipyramidal coordination by centering a triangle of Nd atoms and bridging two Ga atoms. The phase stability and electronic structure of NdGaH1+x, were analyzed by first-principles DFT calculations. NdGaH1H2 (NdGaH2) may be expressed as Nd3+(H1(-)[GaH2](2-). The two-dimensional polyanion [GaH](2-) features linear -H-Ga-H-Ga- chains with alternating short (1.8 A) and long (2.4 angstrom) Ga-H distances, which resembles a Peierls distortion. H2 deficiency (x < 1) results in the fragmentation of chains. For x = 0.66 arrangements with five-atom moieties, Ga-H-Ga-H-Ga are energetically most favorable. From magnetic measurements, the Curie-Weiss constant and effective magnetic moment of NdGaH1.66 were obtained. The former indicates antiferromagnetic interactions, and the latter attains a value of similar to 3.6 mu(B), which is typical for compounds containing Nd3 ions.

  • 2031.
    Århammar, Cecilia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Pietzsch, Annette
    MAX-lab, Lunds universitet, Lund.
    Bock, Nicolas
    Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
    Holmström, Erik
    Instituto di Fisica, Universidad Austral de Chile, Valdivia, Chile.
    Araujo, Carlos Moyses
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Gråsjö, Johan
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Zhao, Shuxi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Green, Sara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Peery, T
    Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
    Hennies, Franz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Amerioun, Shahrad
    Sandvik Tooling, R and D, Stockholm.
    Foehlisch, Alexander
    Insitute for Methods and Instrumentation in Synchrotron Radiation Research G-12, Helmhotz-Zentrum Berlin für Materialien und Energie, Berlin, Tyskland.
    Schlappa, Justine
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Schmitt, Thorsten
    Swiss Light Source, Paul Scherrer Institut, Villigen, Schweiz.
    Strocov, Vladimir N
    Swiss Light Source, Paul Scherrer Institut, Villigen, Schweiz.
    Niklasson, Gunnar A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Wallace, Duane C
    Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
    Rubensson, Jan-Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Mjukröntgenfysik.
    Johansson, Börje
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Ahuja, Rajeev
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Unveiling the complex electronic structure of amorphous metal oxides2011Ingår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 108, nr 16, s. 6355-6360Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Amorphous materials represent a large and important emerging area of material's science. Amorphous oxides are key technological oxides in applications such as a gate dielectric in Complementary metal-oxide semiconductor devices and in Silicon-Oxide-Nitride-Oxide-Silicon and TANOS (TaN-Al2O3-Si3N4-SiO2-Silicon) flash memories. These technologies are required for the high packing density of today's integrated circuits. Therefore the investigation of defect states in these structures is crucial. In this work we present X-ray synchrotron measurements, with an energy resolution which is about 5-10 times higher than is attainable with standard spectrometers, of amorphous alumina. We demonstrate that our experimental results are in agreement with calculated spectra of amorphous alumina which we have generated by stochastic quenching. This first principles method, which we have recently developed, is found to be superior to molecular dynamics in simulating the rapid gas to solid transition that takes place as this material is deposited for thin film applications. We detect and analyze in detail states in the band gap that originate from oxygen pairs. Similar states were previously found in amorphous alumina by other spectroscopic methods and were assigned to oxygen vacancies claimed to act mutually as electron and hole traps. The oxygen pairs which we probe in this work act as hole traps only and will influence the information retention in electronic devices. In amorphous silica oxygen pairs have already been found, thus they may be a feature which is characteristic also of other amorphous metal oxides.

  • 2032.
    Öberg, Viktor
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Johansson, Malin B
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Johansson, Erik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Tuning Size and Composition in Cubic AgBiS2 CQDs for Solar CellsManuskript (preprint) (Övrigt vetenskapligt)
  • 2033. Österberg, Frederik W
    et al.
    Rizzi, Giovanni
    Donolato, Marco
    Bejhed, Rebecca Stjernberg
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Mezger, Anja
    Strömberg, Mattias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Nilsson, Mats
    Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden.
    Strömme, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Nanoteknologi och funktionella material.
    Svedlindh, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Hansen, Mikkel F
    On-Chip Detection of Rolling Circle Amplified DNA Molecules from Bacillus Globigii Spores and Vibrio Cholerae2014Ingår i: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 10, nr 14, s. 2877-2882Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For the first time DNA coils formed by rolling circle amplification are quantified on-chip by Brownian relaxation measurements on magnetic nanobeads using a magnetoresistive sensor. No external magnetic fields are required besides the magnetic field arising from the current through the sensor, which makes the setup very compact. Limits of detection down to 500 Bacillus globigii spores and 2 pM of Vibrio cholerae are demonstrated, which are on the same order of magnitude or lower than those achieved previously using a commercial macro-scale AC susceptometer. The chip-based readout is an important step towards the realization of field tests based on rolling circle amplification molecular analyses.

  • 2034.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Catalytic self-cleaning films for the built environment: Combining facet-texturing, acid-base functionalization and spectral selectivity2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    The possibility to increase human comfort and reduce the global footprint of buildings is a powerful driving force for introduction of new building technology. Here advanced coating technologies play an important role. We demonstrate here that photocatalytic and self-cleaning films can be tailored such that they can be up-scaled with available sputtering technologies. Three approaches to achieve these improved functions are presented. First, we show that facet-texturing to increase the fraction of exposed {001} increases the catalytic activity up to one order of magnitude [1]. In a second approach, surface functionalization of the films by sulfate and nitrate groups renders the surfaces resilient towards deactivation in dry conditions by a proton transfer mechanism [2,3]. In such films bonding of acidic intermediates originating VOC pollutants is avoided which otherwise deactivate their surfaces. In addition, the wetting properties of the TiO2 films are also modified to make them repel e.g. fatty acids and thus possess excellent anti-greasing functionality [4]. In the third approach, TiO2 is deposited on visible-infrared light absorbing films, whereby heat generated in the underlying light absorbing film heats the TiO2 film. We show that increasing the temperature of the TiO2 film results in an increased photocatalytic activity by two mechanisms: thermal activation to increase reaction kinetics, and by shifting the water gas-surface equilibrium coverage to free surface sites for reactant molecules. We generalize the results, and discuss their implications for green building technology and possible scenarios for their implementation.

    [1] B. Stefanov, G. Niklasson, C.G. Granqvist, L. Österlund, J. Mater. Chem. A 2015, 3, 17369-17375.

    [2] B. I. Stefanov, J. Maibach, Z. Topalian, G. A. Niklasson, C. G. Granqvist, L. Österlund, ACS Catal., submitted.

    [3] Z. Topalian, B. Stefanov, C.G. Granqvist, and L. Österlund, J. Catal. 2013, 307, 265-274.

    [4] Z. Topalian, G. Niklasson, and L. Österlund, ACS Appl. Mater. Interfaces 2012, 4, 672−679.

  • 2035.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Characterization of oleophobic and photocatalytic properties of SO2 modified TiO2 thin films2011Ingår i: E-MRS, Warsaw, Poland, 19 Sep – 23 Sep. 2011, Materials Research Society, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present an in situ Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) study of the photo-induced SO2 fixation on anatase TiO2 films. TiO2 films were prepared by DC magnetron sputtering and subsequently exposed to SO2 gas mixed in synthetic air. Simultaneous UV irradiation and SO2 exposure between 373 and 523 K resulted in significant SOx deposits on crystalline TiO2 films as determined by XPS, whereas amorphous films contained negligible amounts of SOx species. The oxidation state of sulfur successively changed from S4+ for SO2 adsorbed on crystalline TiO2 films at room temperature without irradiation to S6+ for films exposed to SO2 at elevated temperatures with simultaneous irradiation. With in situ FTIR the temporal evolution of the photo-induced surface reaction products formed on the TiO2 surfaces was monitored. It is shown that band gap excitation of TiO2 results in photo-induced oxidation of SO2 to form sulfite and sulfate species, which at elevated temperatures become coordinated to the TiO2 surface through interactions with O vacancies. These species makes the oxide surface acidic and is manifested in weak adherence of stearic acid. The films show good stability as evidenced by sonication, repeated stearic acid and rinsing experiments. These results suggest that photo-induced surface treatment in reactive sulfur gases may be interesting for fabrication of oleophobic and anti-greasing coatings. Moreover, the SO2 modified shows excellent properties for sustained decomposition of acetaldehyde, a common indoor air pollutant. This is shown to be due to improved resistance towards site inhibition from carboxylate fragments which otherwise is known to impede the photocatalytic activity of TiO2 in gas-phase applications. Again this is attributed to a beneficial effect of the surface acid sites originating from the surface functionalization.

  • 2036.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Characterization of oleophobic and photocatalytic TiO2 films prepared by surface functionalization with reactive SO2 gas2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present an in situ Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) study of the photo-induced SO2 fixation on anatase TiO2 films. TiO2 films were prepared by DC magnetron sputtering and subsequently exposed to SO2 gas mixed in synthetic air. Simultaneous UV irradiation and SO2 exposure between 373 and 523 K resulted in significant SOx deposits on crystalline TiO2 films as determined by XPS, whereas amorphous films contained negligible amounts of SOx species. The oxidation state of sulfur successively changed from S4+ for SO2 adsorbed on crystalline TiO2 films at room temperature without irradiation to S6+ for films exposed to SO2 at elevated temperatures with simultaneous irradiation. With in situ FTIR the temporal evolution of the photo-induced surface reaction products formed on the TiO2 surfaces was monitored. It is shown that band gap excitation of TiO2 results in photo-induced oxidation of SO2 to form sulfite and sulfate species, which at elevated temperatures become coordinated to the TiO2 surface through interactions with O vacancies. These species makes the oxide surface acidic and is manifested in weak adherence of stearic acid (Fig. 1). The films show good stability as evidenced by sonication, repeated stearic acid and rinsing experiments. These results suggest that photo-induced surface treatment in reactive sulfur gases may be interesting for fabrication of oleophobic and anti-greasing coatings. Moreover, the SO2 modified shows excellent properties for sustained decomposition of acetaldehyde, a common indoor air pollutant. This is shown to be due to improved resistance towards site inhibition from carboxylate fragments which otherwise is known to impede the photocatalytic activity of TiO2 in gas-phase applications. Again this is attributed to a beneficial effect of the surface acid sites originating from the surface functionalization.

  • 2037.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Fourier-Transform Infrared and Raman spectroscopy of pure and doped TiO2 photocatalysts2009Ingår i: On solar hydrogen and nanotechnology / [ed] Lionel Vayssieres, Singapore: Wiley & Sons , 2009, s. 189-238Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 2038.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Mid-infrared diamond waveguides and affinitiy layers on them2017Konferensbidrag (Övrigt vetenskapligt)
  • 2039.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Operando studies of surface reactions in photocatalysis: Photocatalytic oxidation of propane in dry and humid ar on anatase and rutile TiO2 nanoparticles2010Ingår i: Trends in photochemistry and photobiology, ISSN 0972-4532, Vol. 12, s. 53-64Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The photo-oxidation of propane in dry and humid synthetic air was studied on anatase and rutile nanoparticles by operando diffuse reflectance Fourier-transform infrared (DRIFT) spectroscopy and mass spectrometry (MS). Analysis of the propane removal and CO2 production rate shows that the carbon mass balance (CMB) is CMB < 1 under all reaction conditions up to 1 h operation, and that it is significantly higher on rutile than anatase in humid reaction gas. Corresponding analysis of DRIFT spectra acquired simultaneously as the MS measurements shows that the CMB data scales with the concentration of surface species, i.e. the deviations from unity in the reactant-product mass balance (1-CMB) is quantitatively accounted for by a corresponding increase of surface species measured by DRIFT. The identity of surface species and rate determining reactions steps is deduced by fitting the mode-resolved vibrational IR bands to a kinetic model that accounts for observed temporal evolution of absorption bands. Photo-oxidation of acetone and formate is found to be rate determining on anatase and rutile, respectively. The importance of water is to hinder these surface species to bind to Ti cation surface sites; in particular the concentration of bridging-bidentate formate is reduced on rutile, which under dry conditions exhibits the lowest photo-degradation rate.

  • 2040.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Photo-induced surface reactions on transition metal oxide nanoparticles2010Konferensbidrag (Refereegranskat)
  • 2041.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Structure-Reactivity Relationships of Anatase and Rutile TiO2 Nanocrystals Measured by In Situ2010Ingår i: Solid State Phenomena, ISSN 1012-0394, E-ISSN 1662-9779, Vol. 162, s. 203-219Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A comprehensive analysis of structural-reactivity relations on TiO2 nanocrystals is presented. Using an interplay between TEM, X-ray diffraction and vibrational spectroscopy of well-defined anatase and rutile TiO2 nanocrystals correlations between the adsorbate structure of formic acid and the corresponding photo-induced decomposition rate are described. It is demonstrated that the detailed bonding configuration determines the decomposition rate. Generalizations and implications of the findings are discussed.

  • 2042.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Structure-Reactivity Relationships of Anatase and Rutile TiO2 Nanocrystals Measured by In Situ Vibrational Spectroscopy2010Ingår i: Solid State Phenomena, ISSN 1012-0394, E-ISSN 1662-9779, Vol. 162, s. 203-219Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A comprehensive analysis of structural-reactivity relations on TiO2 nanocrystals is presented. Using an interplay between TEM, X-ray diffraction and vibrational spectroscopy of well-defined anatase and rutile TiO2 nanocrystals correlations between the adsorbate structure of formic acid and the corresponding photo-induced decomposition rate are described. It is demonstrated that the detailed bonding configuration determines the decomposition rate. Generalizations and implications of the findings are discussed.

  • 2043.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Study of nanotechnology into cbrn defence2008Konferensbidrag (Refereegranskat)
  • 2044.
    Österlund, Lars
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Andersson, Per Ola
    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.
    Nikolajeff, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Optical sensor unit for evanescence wave spectroscopy2009Patent (Övrig (populärvetenskap, debatt, mm))
  • 2045.
    Österlund, Lars
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Andersson, Per Ola
    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.
    Nikolajeff, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Optical sensor unit for evanescence wave spectroscopy2009Patent (Övrig (populärvetenskap, debatt, mm))
  • 2046.
    Österlund, Lars
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Chakarov, D V
    Chalmers University of Technology.
    Kasemo, B
    Chalmers University of Technology.
    Potassium adsorption on graphite(0001)1999Ingår i: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 420, nr 2-3, s. 174-189Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Potassium adsorption on graphite has been studied with emphasis on the two-dimensional K adlayer below one monolayer. Data are presented for the work function versus coverage, high-resolution electron energy loss spectroscopy (HREELS) vibrational spectra of K-adlayers, low energy electron diffraction and ultraviolet photoemission spectroscopy (UPS) spectra at different coverages. The data provide information regarding the vibrational properties of the K-adlayer, the metallization of the adlayer at submonolayer coverages, and the charge transfer from the It adatoms to the graphite substrate. Analysis of the work function, HREELS, and UPS data provides a qualitatively consistent picture of the charge state of the K adatoms, where at low coverages, below a critical coverage theta(c) (theta(c) = 0.2-0.3), the K adatoms are dispersed and (partially) ionized, whereas at theta > theta(c) islands of a metallic 2 x 2 K phase develop that coexist with the dispersed K adatoms up to theta = 1. We show that it is possible to understand the variation of the work function data based on a two-phase model without invoking a depolarization mechanism of adjacent dipoles, as is normally done for alkali-metal adsorption on metal surfaces. Similarly, the intensity variation as a function of coverage of the energy loss peak at 17 meV observed in HREELS, and the photoemission peak at E-b = 0.5 eV seen in UPS can be understood from a two-phase model. A tentative explanation is presented that connects apparent discrepancies in the literature concerning the electronic structure of the K adlayer. In particular, a new assignment of the K-induced states near the Fermi level is proposed. (C) 1999 Elsevier Science B.V. All rights reserved.

  • 2047.
    Österlund, Lars
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Grant, A. W.
    Chalmers University of Technology.
    Kasemo, B.
    Chalmers University of Technology.
    Lithographic Techniques in Nanocatalysis2007Ingår i: NANOCATALYSIS / [ed] U. Heiz, and U. Landman, Springer Berlin/Heidelberg, 2007, s. 269-341Kapitel i bok, del av antologi (Refereegranskat)
  • 2048.
    Österlund, Lars
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Karlsson, M.
    Andersson, P. O.
    Nikolaeff, Fredrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    EP patent2013Patent (Övrig (populärvetenskap, debatt, mm))
  • 2049.
    Österlund, Lars
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kielbassa, S
    Chalmers University of Technology.
    Werdinius, C
    Chalmers University of Technology.
    Kasemo, B
    Chalmers University of Technology.
    Reactivity of Pt/ceria and Pt/alumina planar model catalysts prepared by colloidal lithography2003Ingår i: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 215, nr 1, s. 94-107Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report on the structure, chemical state, and catalytic activity of nanofabricated, planar Pt/ceria and Pt/alumina model catalysts prepared by colloidal lithography. Employing extended etching times, catalyst particles are fabricated that are much smaller than the size of the polystyrene colloidal particle mask. Using CO oxidation as a probe reaction, the influence of various pretreatments has been studied. We find that the H-2/O-2 pretreatment deteriorates the reactivity on Pt/alumina, which is accompanied by blocking of the high-temperature CO adsorption sites as seen by TPD. After prolonged reactions the Pt/ceria particles show pronounced restructuring, indicating a low-temperature, reaction-induced, strong metal-support interaction, where ceria is decorating the Pt particles. In contrast, after an identical reaction history the Pt/alumina particles become facetted. The nanofabrication approach allows us to attribute the structural changes on individual particles to the integrated, macroscopic catalytic response. (C) 2003 Elsevier Science (USA). All rights reserved.

  • 2050.
    Österlund, Lars
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kiselev, A.
    Mattsson, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    New nanomaterials for active decontamination of chemical warfare agents2005Ingår i: Second International Conference on Military Technology / [ed] S. Axberg, Stockholm, Sverige: Nyberg&Co , 2005, s. 387-394Kapitel i bok, del av antologi (Refereegranskat)
3839404142 2001 - 2050 av 2076
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