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131.
Rasa Kazakevičiūtė‐Makovska Safa Mogharebi Holger Steeb Gunther Eggeler Klaus Neuking 《Advanced Engineering Materials》2013,15(8):732-739
Experimental study of temperature‐ and frequency‐dependent properties of the commercially available shape memory polymer Tecoflex? EG 72D (TFX) (Lubrizol, USA) using dynamic mechanical analysis (DMA) technique is presented. Temperature scan DMA tests have been carried out in three distinct deformation modes, uniaxial tension, three‐point bending, and simple torsion, using two different testing rigs at different test parameters (frequency, strain amplitude, and heating rate) in temperatures ranging from below to above the glass transition temperature. The influence of different test parameters and some discrepancies in the temperature‐dependent storage and loss moduli (and hence the loss factor) measured by DMA in different deformation modes are discussed. 相似文献
132.
Małgorzata Sopicka-Lizer Daniel Michalik Julian Plewa Thomas Juestel Holger Winkler Tomasz Pawlik 《Journal of the European Ceramic Society》2012,32(7):1383-1387
The present paper describes the effect of various Si–N substitution degree on the crystal structure and optical properties of yellow YAG:Ce phosphor commonly used with combination of InGaN in white LEDs. It has been found that the course of silicon/nitrogen YAG:Ce garnet doping as well as formation of the liquid phase and its chemical composition controlled formation of the side phase besides YAG:Ce. Substitution of Al–O for Si–N chemical bonds according to the general formula Y2.94Ce0.06Al(5?x)SixO(12?x)Nx was confirmed by changes of the unit cell parameter and formation of the Si–N bonds as detected by FT-IR studies. Formation of the nitrogen ligand in cerium arrangement resulted in a red shift in emission spectrum of trivalent cerium if nominal x value was in the range of 0.2–0.3. Above x = 0.3 only decrease of emission intensity was observed because of the secondary phase precipitation but further solution of Si–N in YAG:Ce crystal lattice cannot be excluded. 相似文献
133.
Michael Sander Rainer Gehring Holger Neumann Thomas Jordan 《International Journal of Hydrogen Energy》2012
A new energy storage concept for variable renewable energy, LIQHYSMES, has been proposed which combines the use of LIQuid HYdrogen (LH2) with Superconducting Magnetic Energy Storage (SMES). LH2 with its high volumetric energy density and, compared with compressed hydrogen, increased operational safety is a prime energy carrier for large scale stationary energy storage. But balancing load or supply fluctuations from seconds to several hours with hydrogen alone is difficult due to the response times of the flow control, and an additional short-term electrical energy storage will be needed. For this purpose a compact LIQHYSMES Storage Unit is proposed which integrates the H2 liquefaction part, the LH2 tank and the SMES based on Magnesium Diboride and cooled by the LH2 bath. This allows jointly utilizing the cryogenic infrastructure and reducing the otherwise significant H2 liquefaction losses by introducing a novel process with “cold recovery”. Preliminary target numbers for this process, key parameters for a complete LIQHYSMES model plant, simulations on the anticipated buffering behaviour, a loss analysis and a crude cost estimate are given. 相似文献
134.
The proportion of sustainable property in the total building stock remains small. One reason is that the financial added value resulting from sustainability is not sufficiently taken into account in property valuation due to the tendency of valuations to lag behind market trends. Quantitative information is provided to integrate those aspects of sustainability relating to value into valuations and thereby contribute to the reduction of valuation lag. The Centre for Corporate Responsibility and Sustainability (CCRS) Economic Sustainability Indicator (ESI) measures the risk of property to lose value and the opportunity to gain value due to future developments (e.g. climate change or rising energy prices). Five groups of value-related sustainability features were identified: flexibility and polyvalence; energy and water dependency; accessibility and mobility; security; and health and comfort. By minimizing the risk of loss in value through future developments, those sustainability features contribute to the property value. Their effects on property value were quantified by risk modelling. As an indicator for future-oriented property risk, the ESI is integrated into the discount rate of discounted cash flow valuations. The approach was tested for plausibility and practicability on more than 200 properties. La proportion de biens immobiliers durables dans le parc immobilier total demeure faible. L'explication tient pour une part au fait que la valeur ajoutée financière résultant de la durabilité n'est pas suffisamment prise en compte dans l'évaluation des biens immobiliers en raison du fait que les évaluations tendent à avoir du retard sur les tendances du marché. Des informations quantitatives sont fournies afin d'intégrer les aspects de la durabilité liés à la valeur dans les évaluations et de contribuer ainsi à la réduction du retard dans les évaluations. L'Indicateur de Durabilité Economique (ESI) du Centre pour la Responsabilité et la Durabilité en Entreprise (CCRS) mesure le risque de perte de valeur des biens immobiliers et la possibilité d'en accroître la valeur du fait des évolutions futures (par ex. changement climatique et hausse des prix énergétiques). Cinq groupes de fonctions de durabilité liées à la valeur ont été identifiés: flexibilité et polyvalence, dépendance vis-à-vis de l'énergie et de l'eau; accessibilité et mobilité; sécurité; santé et confort. En minimisant le risque d'une perte de valeur causée par les évolutions futures, ces fonctions de durabilité contribuent à la valeur des biens immobiliers. Leurs effets sur la valeur des biens immobiliers ont été quantifiés par une modélisation des risques. En tant qu'indicateur du risque prospectif pour les biens immobiliers, l'ESI est intégré au taux d'actualisation des flux de trésorerie actualisés. Cette approche a été testée quant à sa plausibilité et sa praticabilité sur plus de 200 biens immobiliers. Mots clés: flux de trésorerie actualisés, indicateur de durabilité économique, évaluation des biens immobiliers, modèle de risque, fonctions de durabilité, durabilité, bâtiments durables 相似文献
135.
Gábor Erdélyi Lane A. Hemaspaandra Jörg Rothe Holger Spakowski 《Information Processing Letters》2009,109(16):946-949
We prove that every distributional problem solvable in polynomial time on the average with respect to the uniform distribution has a frequently self-knowingly correct polynomial-time algorithm. 相似文献
136.
Sonja Berg Melanie J. Leng Christopher P. Kendrick Holger Cremer Bernd Wagner 《SILICON》2013,5(1):19-34
Organic carbon occluded in diatom silica is assumed to be protected from degradation in the sediment. δ13C from diatom carbon (δ13C(diatom)) therefore potentially provides a signal of conditions during diatom growth. However, there have been few studies based on δ13C(diatom). Numerous variables can influence δ13C of organic matter in the marine environment (e.g., salinity, light, nutrient and CO2 availability). Here we compare δ13C(diatom) and δ13C(TOC) from three sediment records from individual marine inlets (Rauer Group, East Antarctica) to (i) investigate deviations between δ13C(diatom) and δ13C(TOC), to (ii) identify biological and environmental controls on δ13C(diatom) and δ13C(TOC), and to (iii) discuss δ13C(diatom) as a proxy for environmental and climate reconstructions. The records show individual δ13C(diatom) and δ13C(TOC) characteristics, which indicates that δ13C is not primarily controlled by regional climate or atmospheric CO2 concentration. Since the inlets vary in water depths offsets in δ13C are probably related to differences in water column stratification and mixing, which influences redistribution of nutrients and carbon within each inlet. In our dataset changes in δ13C(diatom) and δ13C(TOC) could not unequivocally be ascribed to changes in diatom species composition, either because the variation in δ13C(diatom) between the observed species is too small or because other environmental controls are more dominant. Records from the Southern Ocean show depleted δ13C(diatom) values (1–4 ‰) during glacial times compared to the Holocene. Although climate variability throughout the Holocene is low compared to glacial/interglacial variability, we find variability in δ13C(diatom), which is in the same order of magnitude. δ13C of organic matter produced in the costal marine environment seems to be much more sensitive to environmental changes than open ocean sites and δ13C is of strongly local nature. 相似文献
137.
138.
Egbert Woelk Holger Jürgensen Randy Rolph Tim Zielinski 《Journal of Electronic Materials》1995,24(11):1715-1718
We use low pressure MOVPE to grow indium antimonide films on groups of eight 3 inch GaAs wafers per run. The films are used
for the production of magnetoresistive position sensors for the car industry. To meet the narrow specifications for automotive
components, the standard deviation of the sheet resistivity, and the thickness of the films have been reduced below 1.5%.
This uniformity is the result of an optimization process encompassing the determination of the best susceptor temperature
and the optimum flow. The gas velocity was found to have a large impact on the uniformity of the layers. Rotation of the wafers
and the use of an optimum gas velocity results in extremely uniform layers. 相似文献
139.
An optimal treatment (surface modification, coating) of micro‐disperse materials (powder, granulate, fibres etc.) by a process plasma requires the understanding of plasma‐particle interaction. For this purpose, related experimental investigations in a novel set‐up PULVA‐INP will be presented. 相似文献
140.