Change search
Refine search result
1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Andersson, Kent
    et al.
    Uppsala universitet.
    Veszelei, Monica
    Uppsala Universitet.
    Roos, Arne
    Uppsala Universitet.
    Zirconium nitride based transparent heat mirror coatings: preparation and characterisation1994In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 32, no 2, p. 199-212Article in journal (Refereed)
    Abstract [en]

    Transparent heat mirror coatings based on thin zirconium nitride films have been prepared using reactive magnetron sputtering. The zirconium nitride films have been sandwiched between layers of zirconium oxide. It is shown that the multilayer configuration ZrO2/ZrN/ZrO2 can be used as solar control coatings on window glazings. A visible transmittance of around 60% and a thermal emittance lower than 0.2 can be obtained, and the ratio between visible transmittance and total solar transmittance can be as high as 1.7. The influence of substrate temperature on the optical quality of the films is evaluated and it is shown that the crystal structure of the first oxide layer is of importance for the optical quality of the nitride. The influence of preparation conditions and accelerated ageing has been modelled using the optical constants of thin films prepared under identical conditions as the films in the multilayer coatings.

  • 2.
    Andersson, Kent
    et al.
    Uppsala universitet.
    Wahlström, M.K.
    Uppsala Universitet.
    Roos, Arne
    Uppsala Universitet.
    High stability titanium nitride based solar control films1992In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 214, no 2, p. 213-218Article in journal (Refereed)
    Abstract [en]

    Triple-layer structures of TiO2TiN/TiO2 and quadruple layer structures of TiO2Al/TiN/TiO2 have been sputtered on glass substrates at temperatures ranging from room temperature to 300°C. The reflectance and transmittance were measured in the visible and the near-IR wavelength regions. The thin layer of aluminium, in the quadruple layer, oxidizes and forms a dense diffusion barrier. The multilayers exhibit improved optical selectivity which also improves with substrate temperature up to 300°C.

  • 3.
    Bröms, Andreas
    Swedish National Defence College.
    Är nästa plattform obemannad för svensk signalspaning?: Systemanalys av Global Hawk som potentiell ersättande plattform av Gulfstream G4-SP2014Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Signal intelligence (SIGINT) has since a period of time been a part of the Swedish armed forces ability and during the Cold War due to events this was not a safe and easy task to perform. Considering that the present system is beginning to become outdated, a plan to replace this system should be at its place in a short amount of time.The purpose with this study is, by using a system analysis method, find a suitable replacer for the present platform which is Gulfstream GIV-SP, carrying signal intelligence equipment. The comparative platform that has been used in this study is the Global Hawk which is a modern strategic UAV. The two platforms that are compared have been linked to the theory of the basic capabilities, the theory is delimited to Intelligence/Information, Endurance and Protection which the performance of the platforms creates.The study result in a conclusion that the Global Hawk fulfills this basic capabilities with most efficiency and the differences of an unmanned platform is positive. In terms of intelligence the platforms is rather equal and causes advantages in their own different ways but in terms of endurance and protection the Global Hawk is more efficient.The study´s conclusion is that the Global Hawk is the more efficient platform for carrying signal intelligence equip-ment but due to the high cost of the system, it is not suitable for the Swedish armed forces. However, it should be considered as a possible replacement platform in the future, as the maintenance cost decreased and the number of user has increased.

  • 4.
    Khaji, Zahra
    et al.
    Uppsala University.
    Sturesson, Peter
    Swedish Defence University, Department of Military Studies, Military-Technology Division. Uppsala University.
    Hjort, Klas
    Uppsala University.
    Klintberg, Lena
    Uppsala University.
    Thornell, Greger
    Uppsala University.
    Investigation of the storage and release of oxygen in a Cu-Pt element of a high-temperature microcombustor2014In: Journal of Physics Conference Series, Institute of Physics Publishing (IOPP), 2014Conference paper (Refereed)
    Abstract [en]

    A miniature combustor for converting organic samples into CO2 with application in carbon isotopic measurements has been manufactured and evaluated. The combustor was made of High-Temperature Co-fired Ceramic (HTCC) alumina green tapes. The device has a built-in screen printed heater and a temperature sensor made of platinum, co-sintered with the ceramic. A copper oxide oxygen supply was added to the combustor after sintering by in-situ electroplating of copper on the heater pattern followed by thermal oxidation. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Thermal Gravimetric Analysis (TGA) were used to study electroplating, oxidation and the oxide reduction processes. The temperature sensor was calibrated by use of a thermocouple. It demonstrates a temperature coefficient resistance of 4.66×10−3/°C between 32 and 660 °C. The heat characterization was done up to 1000 °C by using IR thermography, and the results were compared with the data from the temperature sensor. Combustion of starch confirmed the feasibility of using copper oxide as the source of oxygen of combustion.

  • 5.
    Sturesson, Peter
    Swedish Defence University, Department of Military Studies, Science of Command and Control and Military Technology Division, Military Technology Systems Section. Ångström Space Technology Centre (ÅSTC), Uppsala University, Sweden.
    Sense, Actuate and Survive: Ceramic Microsystems for High-Temperature Aerospace Applications2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In aerospace applications, but also in manufacturing, mining, energy industry and natural hazards, high temperature, corrosion, erosion and radiation, challenge the performance and being of hardware.

    In this work, high-temperature co-fired ceramic (HTCC) alumina and platinum have been used for a range of devices intended for aerospace applications at up to 1000°C.

    The thermomechanics of a pressure sensor was investigated, and the interfacing was attained by wireless powering and reading. However, read range was limited and sensitivity decreased with temperature. Silver, electroplated after sintering, was found to remedy this until it eventually alloyed with platinum.

    Copper was electroplated and oxidized for oxygen storage in a microcombustor, intended for sample preparation for optogalvanic spectroscopy (OGS) to indicate extraterrestrial life. Despite delamination, caused by residual stresses, the device operated successfully.

    Conversely, pre-firing metallization by integration of platinum wires was studied. Freely suspended, and despite heat-induced shape irregularities, these were found advantageous over screen printed elements for gas heating, and temperature and pressure sensing. By fusing off the wires, spherical tips, allowing for impedance monitoring of microplasma sources in, e.g., OGS, were formed.

    Microplasma sources can also be used for gas heating. This, together with screen printed and suspended resistive heaters, was evaluated in a microthruster, showing that plasma heating is the most effective, implying fuel consumption reduction in satellite propulsion.

    In conclusion, HTCC alumina microdevices are thermally stable and could benefit several aerospace applications, especially with the complementary metallization schemes devised here.

    Future developments are expected to include both processing and design, all with the intention of sensing, actuating and surviving in high-temperature environments.

  • 6.
    Theorin, Anders
    Swedish Defence University.
    Försämrade materialegenskaper i aluminiumkonstruktioner - Liquid Metal Embrittlement inducerat av gallium2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The possibility to damage enemy constructions using an efficient method, which might permit a low risk of detection, is studied in this thesis. This damage is based on the phenomena Liquid Metal Embrittlement (LME) with which high strength metals can be affected so much that they collapse under their own weight. This thesis studies this effect in a material often used for various constructions, both civilian and military. An experiment was conducted in order to evaluate the effects of LME on an aluminium alloy by exposing the aluminium to the metal known as gallium. A pre-experiment was made in order to determine how the time of exposure affected the LME-process and time-periods were decided accordingly. At each of the timeperiods a yield test was conducted in order to measure losses in strength and elasticity of the aluminium. It was shown that a great reduction in strength and elasticity occurred, where the strength was reduced to 20% of the reference sample and elasticity to 1% of the reference sample.

  • 7.
    Veszelei, Monica
    et al.
    Uppsala Universitet.
    Andersson, Kent
    Uppsala Universitet.
    Ribbing, C G
    Uppsala Universitet.
    Järrendahl, K
    Linköpings Tekniska Högskola.
    Arwin, H
    Linköpings Tekniska Högskola.
    Optical constants and Drude analysis of sputtered zirconium nitride films1994In: Applied Optics, ISSN 0003-6935, E-ISSN 1539-4522, Vol. 33, no 10, p. 1993-2001Article in journal (Refereed)
    Abstract [en]

    Opaque and semitransparent dc magnetron-sputtered ZrN films on glass and silicon have been optically characterized with spectral reflectance measurements and ellipsometry. High rate sputtered ZrN has good optical selectivity, i.e., higher than 90% infrared reflectance and a pronounced reflectance step in the visible to a reflectance minimum of less than 10% at 350 nm. The results are comparable with those obtained for single crystalline samples and those prepared by chemical vapor deposition. The complex optical constant (N = n v ik) for opaque films has been determined in the 0.23-25-µm wavelength range with Kramers-Kronig integration of bulk reflectance combined with oblique incidence reflectance for p-polarized light. A variable angle of incidence spectroscopic ellipsometer has been used for determination of the optical constants in the 0.28-1.0-µm wavelength region. The results of the two methods show excellent agreement. The results indicate that ZrN is free electronlike and the Drude model can be applied. The best opaque films had Drude plasma energies (ħω(p) between 6.6 and 7.5 eV and relaxation energies (ħ/τ) between 0.29 and 0.36 eV. Ellipsometer data for the semitransparent films show that the refractive index (n) in the visible increases with decreasing film thickness whereas the extinction coefficient (k) is essentially unchanged. The optical properties are improved by deposition upon a heated substrate.

  • 8.
    Veszelei, Monica
    et al.
    Uppsala Universitet.
    Andersson, Kent
    Uppsala Universitet.
    Roos, Arne
    Uppsala Universitet.
    Optical characterization of sputtered semitransparent zirconium nitride films1993In: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 2, no 4, p. 257-266Article in journal (Refereed)
    Abstract [en]

    Thin semi-transparent ZrN films have been prepared using reactive dc magnetron sputtering. The films had thickness from 11 to 43 nm and were grown on heated and room temperature glass substrates. The optical constants, N=n+ik, of the thin films have been determined with an RT inversion method in the wavelength interval 0.40 to 2.0 μm. The thickness of the films was determined from the photometric measurements. The optical properties of the thin films on glass were compared to opaque and thin ZrN films grown on single crystalline Si. The Drude parameters were calculated from the measured optical constants in the relaxation region of the thin films. The relaxation time, τ, of the thin films was found to increase with film thickness, substrate temperature and substrate crystallinity. The relaxation time is the mean free time for the electrons between collisions and a long relaxation time corresponds to a film with high optical quality. The observed decrease of τ with decreasing film thickness can be explained by the higher statistical probability of the electrons in a thin film to collide with the two surfaces of the film. Another explanation to the decrease of τ with film thickness is scattering from grain boundaries and lattice impurities. The higher optical quality of films grown on heated substrates is probably due to an increased grain size. The measured optical constants were compared with calculated optical constants, using the Drude model, and the optical behaviour of thin ZrN films was found to be well described by the screened free-electron model.

1 - 8 of 8
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf