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391.
Serap Günes Karolina P. Fritz Helmut Neugebauer Niyazi Serdar Sariciftci Sandeep Kumar Gregory D. Scholes 《Solar Energy Materials & Solar Cells》2007,91(5):420-423
Solution-processed bilayer heterojunction hybrid solar cells have been fabricated using size-quantized PbS nanoparticles and poly (3-hexylthiophene) (P3HT). PbS was used as an electron-transporting layer whereas P3HT was used for hole transport. A photovoltaic device consisting of PbS and P3HT exhibited 3% incident photon to current efficiencies (IPCE) under 550-nm monochromatic irradiation. 相似文献
392.
393.
In this study, effects of cement type, cement content and water/cement (W/C) ratio level on the sea water resistance of concrete were investigated. Test samples were exposed to sea water by wetting–drying manner. Residual splitting tensile and compressive strength, and chloride penetration depths of specimens after exposure were determined. Besides, energy dispersive spectrometer (EDS) analyses were performed on scanning electron microscope (SEM) images of selected mixtures. Test results indicate that blast furnace slag cement (SC) mixtures have considerably greater resistance to sea water than portland cement (PC) mixtures both from the point of mechanical properties and chloride penetration. 相似文献
394.
Serdar Aydn 《Fire Safety Journal》2008,43(8):610-617
The effects of high temperatures up to 900 °C on the mechanical properties and the microstructure of cement-based pumice mortars incorporating different amounts of ground granulated blast furnace slag (GGBFS) were investigated in this study. The residual compressive and flexural strength of mortar specimens were determined after exposure to high temperatures. The results have indicated that the effect of GGBFS incorporation on high-temperature resistance of pumice mortar is shown significantly at 900 °C. At this temperature level, the mortar containing 80% GGBFS exhibited only 23% and 28% compressive strength loss when cooled in air and water, respectively, where as mortars without GGBFS lost almost 70% of their strength. Furthermore, none of the GGBFS incorporated mortar specimens showed compressive strength loss up to 600 °C when cooled in air. The most severe conditions in terms of strength loss due to high temperatures were flexural loading and water cooling case. 相似文献
395.
Influence of synthesis conditions on particle morphology of nanosized Cu/ZnO powder by polyol method
Cu/ZnO in nanosizes have been synthesized using ethylene glycol at various conditions. The effects of reaction temperature,
extent of reduction, various precursors such as CuX2·nH2O, ZnX2·nH2O (X = Cl−, NO3−, CH3CO2−), the addition of water and the removal of volatile compounds including water were studied by X-ray diffraction (XRD), scanning
electron microscopy (SEM), and dynamic light scattering (DLS). Cu/ZnO powders with an average diameter of as low as 50 nm
was obtained with a very low polydispersity in the absence of a protective polymer. Ethylene glycol oxidation products were
also identified by Fourier transform infrared (FTIR) spectroscopy. The morphology of Cu/ZnO powders and the yield of powders
are found to be strongly dependent on the synthesis conditions. 相似文献
396.
We report on the photovoltaic performance of bulk heterojunction solar cells using novel nanoparticles of 6-palmitate ascorbic acid surface modified TiO(2) as an electron acceptor embedded into the donor poly(3-hexyl)thiophene (P3HT) matrix. Devices were fabricated by using P3HT with varying amounts of red TiO(2) nanoparticles (1:1, 1:2, 1:3?w-w ratio). The devices were characterized by measuring current-voltage characteristics under simulated AM 1.5 conditions. Incident photon to current efficiency (IPCE) was spectrally resolved. The nanoscale morphology of such organic/inorganic hybrid blends was also investigated using atomic force microscopy (AFM). 相似文献
397.
Nanosized catalysts composed of metallic copper supported on zinc oxide have been synthesized by the polyol process. Average crystallite size of copper was between 10 and 45 nm. Cu/ZnO catalyst particles were characterized by various techniques, such as X-ray Powder Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED), and dynamic light scattering analysis (DLS). 相似文献
398.
Bulent Aktas Suleyman Tekeli Serdar Salman 《Journal of Materials Engineering and Performance》2014,23(1):294-301
In this study, 8 mol% yttria-stabilized cubic zirconia (8YSZ) powder as a matrix material and 0-15 wt.% La2O3 powder as an additive were used to determine the effect of La2O3 addition and its amount on the phase stability, microstructure, sintering, and mechanical properties of 8YSZ. Colloidal processing was used to mix the powders uniformly and to obtain a homogenous microstructure. XRD results showed the existence of only a cubic crystal structure for 1 and 5 wt.% La2O3 addition amounts. However, La2Zr2O7 with a hexagonal and cubic crystal structure was observed in 8YSZ specimens doped with 10 and 15 wt.% La2O3. Further, up to 5 wt.% La2O3 was completely dissolved in the crystal structure of the specimens; however, above 5 wt.%, La2O3 reacted with 8YSZ at high temperatures and formed pyrochloric La2Zr2O7. Grain size measurements revealed that the grain size of 8YSZ increased up to 1 wt.% La2O3 addition, and then decreased beyond this amount. The hardness and fracture toughness of 8YSZ decreased and increased, respectively, with the increasing La2O3 amount. 相似文献
399.
Hansen BH Altin D Rørvik SF Øverjordet IB Olsen AJ Nordtug T 《The Science of the total environment》2011,409(4):704-709
Extrapolation of ecotoxicological data from temperate species for use in risk assessment in the polar environments may be difficult since polar organisms as a rule differ from temperate species in terms of life span length, developmental time, surface-to-volume ratios, metabolic rates, total energy usage and lipid content for energy storage. In the current work we performed a comparative study where two closely related and morphologically similar copepod species, Calanus finmarchicus (temperate-boreal) and Calanus glacialis (arctic), were exposed to water accommodated fractions (WAF) of oil in a series of parallel experiments. The two species, adapted to 10 °C and 2 °C, respectively, were compared on the basis of acute ecotoxicity (LC50) and the WAF-mediated induction of the gene encoding glutathione S-transferase (GST). In addition, an experiment was conducted in order to reveal relationships between lipid content and acute toxicity. LC50 values differed between the two species, and the Arctic copepod appeared less sensitive than the temperate-boreal species. The lipid contents of the two species, measured biometrically, were comparable, and the relationships between lipid content and response (reduced survival) to acute WAF exposure followed the same trend: Lipid-rich copepods survived longer than lipid-poor copepods at the same exposure concentration. In terms of GST expression, both species showed concentration-dependent and exposure time-dependent trends. However, as for the acute toxicity data, the Arctic copepod appeared to respond slower and with a lower intensity. From the study it can be concluded that temperature and lipid content are important factors for assessing differences between temperate and Arctic species, and that a delayed response in organisms adapted to low temperatures needs to be corrected for when extrapolating toxicity data from species with other temperature optimums for use in Arctic environments. 相似文献
400.
Görür FK Keser R Akçay N Dizman S As N Okumuşoğlu NT 《Journal of the science of food and agriculture》2012,92(2):307-312
BACKGROUND: Rize in Turkey was contaminated by the Chernobyl accident in 1986. A comprehensive study was planned and carried out to determine the radioactivity levels and heavy metal concentrations in four food categories collected in Rize in 2008, 2009 and 2010. RESULTS: Tomato showed the highest concentration of 238U, at 9.43 ± 0.128 Bq kg?1, whereas the lowest concentration of 0.20 ± 0.02 Bq kg?1 was measured in aubergine samples. The highest concentration of 232Th was measured at 3.22 ± 0.29 Bq kg?1 in grape samples. 40K was found to contribute the highest activity in all the food samples. The highest activity concentration of 137Cs was 10.20 ± 4.19 Bq kg?1, for parsley. The average contribution range of each of the heavy metals to the dietary intake was 0.13–9.14, 0.27–34.63, 0.05–3.62, 0.11–14.97, 0.78–8.51 and 0.01–1.57 mg, respectively, for Mn, Fe, Cu, Zn, Ni and As. CONCLUSION: The range of radioactivity levels in food samples of the present study is of no risk to public health. Heavy metal concentrations of Mn, Fe, Cu, Zn, Ni and As obtained were far below the established values by FAO/WHO limits. Copyright © 2011 Society of Chemical Industry 相似文献