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91.
Filters used for building general ventilation are tested since more than 20 years, and there is always a heavy discussion about the usability of test data under lab conditions. New is the introduction of a minimum efficiency (EN779; draft). In this study filters are mounted in the ventilation system for 3 and 6 month. Afterwards fractional efficiencies are measured with a DEHS aerosol in a test rig. In addition tests are performed using diesel soot as loading aerosol or isopropanol to reduce the electrostatic charge on the synthetic fibers. The results show a strong influence of the efficiency on the test procedure and very loosely agreement of these results with those using ASHRAE dust. 相似文献
92.
Scanning electrochemical microscopy (SECM) in its alternating current mode (AC-SECM) has been of growing importance to detect and interpret local variations of electrochemical surface properties with high spatial resolution. The sensitivity of AC-SECM and hence the quality of imaging was found to be highly dependent on the experimental conditions. It was commonly judged using approach curves in the distance domain. As an alternative to current-distance approach curves, the coordinate system based on real and imaginary part of impedance is suggested for their display. In this framework, the difference between the impedance vector magnitude, real or imaginary part of impedance over neighboring surfaces is considered as a measure of imaging contrast. The variable which grants maximum difference is selected for imaging while measurement conditions associated with this maximum indicate optimum scanning conditions. The methodology of determining these optimized parameters is laid out in this contribution and examples are given. Since the optimum parameters are identified before the actual lateral imaging, this time-saving method facilitates the visualization of local electrochemical properties at the highest possible quality. 相似文献
93.
In 1995 at the integral test facility ISB-VVER in Elektrogorsk near Moscow natural circulation experiments were performed, which were scientifically accompanied by the Forschungszentrum Rossendorf. These experiments were the first of this kind at a test facility, which models VVER-1000 thermalhydraulics. Using the code ATHLET which is being developed by ‘Gesellschaft für Anlagen und Reaktorsicherheit’, pre- and post-test calculations were done to determine the thermalhydraulic events to be expected and to define and tune the boundary conditions of the test. The conditions found for natural circulation instabilities and cold leg loop seal clearing could be confirmed by the tests. Besides the thermalhydraulic standard measuring system, the facility was equipped with needle shaped conductivity probes for measuring the local void fractions. 相似文献
94.
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96.
Heide Budde-Meiwes Julia KowalDirk Uwe Sauer Eckhard Karden 《Journal of power sources》2011,196(23):10415-10423
Many battery simulation models, but also electrochemical interpretations are based on impedance spectroscopy. However, the impedance of a battery is influenced by various factors, e.g. in the case of a lead-acid battery: state of charge (SOC), charging or discharging, superimposed dc current, short-term history or homogeneity of the electrolyte. This paper analyses the impact of those factors on impedance spectra of lead-acid batteries. The results show that very detailed information about the conditions during the measurement is crucial for the correct interpretation of a spectrum. 相似文献
97.
98.
Results are presented on the construction of a thin‐layer photovoltaic cell on glass‐fiber fabric. The unevenness of the fabric was first smoothed by the application of a high‐temperature stable resin before photovoltaic layer deposition. We obtained an efficiency of light‐to‐current conversion of more than 8%. This constitutes a remarkably high value for a photovoltaic cell on a flexible substrate. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
99.
Bartosz Krajnik Magdalena Gajda-R?czka Dawid Pi?tkowski Piotr Nyga Bart?omiej Jankiewicz Eckhard Hofmann Sebastian Mackowski 《Nanoscale research letters》2013,8(1):146
In this work we demonstrate enhancement of the fluorescence collection efficiency for chlorophyll-containing photosynthetic complexes deposited on SiO2 spherical nanoparticles. Microscopic images of fluorescence emission reveal ring-like emission patterns associated with chlorophyll-containing complexes coupled to electromagnetic modes within the silica nanoparticles. The interaction leaves no effect upon the emission spectra of the complexes, and the transient behavior of the fluorescence also remains unchanged, which indicates no influence of the silica nanoparticles on the radiative properties of the fluorophores. We interpret this enhancement as a result of efficient scattering of electromagnetic field by the dielectric nanoparticles that increases collection efficiency of fluorescence emission. 相似文献
100.
Ramesh Chandra Mallik Christian Stiewe Gabriele Karpinski Ralf Hassdorf Eckhard Müller 《Journal of Electronic Materials》2009,38(7):1337-1343
The properties of Co4Sb12 with various In additions were studied. X-ray diffraction revealed the presence of the pure δ-phase of In0.16Co4Sb12, whereas impurity phases (γ-CoSb2 and InSb) appeared for x = 0.25, 0.40, 0.80, and 1.20. The homogeneity and morphology of the samples were observed by Seebeck microprobe and scanning
electron microscopy, respectively. All the quenched ingots from which the studied samples were cut were inhomogeneous in the
axial direction. The temperature dependence of the Seebeck coefficient (S), electrical conductivity (σ), and thermal conductivity (κ) was measured from room temperature up to 673 K. The Seebeck coefficient of all In-added Co4Sb12 materials was negative. When the filler concentration increases, the Seebeck coefficient decreases. The samples with In additions
above the filling limit (x = 0.22) show an even lower Seebeck coefficient due to the formation of secondary phases: InSb and CoSb2. The temperature variation of the electrical conductivity is semiconductor-like. The thermal conductivity of all the samples
decreases with temperature. The central region of the In0.4Co4Sb12 ingot shows the lowest thermal conductivity, probably due to the combined effect of (a) rattling due to maximum filling and
(b) the presence of a small amount of fine-dispersed secondary phases at the grain boundaries. Thus, regardless of the non-single-phase
morphology, a promising ZT (S
2
σT/κ) value of 0.96 at 673 K has been obtained with an In addition above the filling limit. 相似文献