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981.
Deepak Tyagi Salil VarmaK. Bhattacharya D. JainA.K. Tripathi C.G.S. PillaiS.R. Bharadwaj 《International Journal of Hydrogen Energy》2012
Bunsen reaction is an important step of sulfur–iodine cycle for hydrogen production from thermochemical splitting of water. Polyiodide species generated during the separation process need to be identified for complete understanding of the mechanism involved. Speciation of these polyiodide species formed during Bunsen reaction can lead to better understanding of kinetics of the process. HIx species formed have been analyzed using UV–visible and Raman spectroscopic techniques. Peak corresponding to HI3 species have been ascertained and their conversion to higher HI5, HI7 …… species has been observed. 相似文献
982.
为了简化农药检测的预测模型,提高模型预测精度,采用红外光谱技术结合基于变异的紧凑遗传算法对波长变量进行筛选,一定程度上减少了无信息变量和干扰变量。通过不同算法选择的波长变量建立预测模型,mCGA得到的预测均方根偏差平均值是0.198,而与mCGA比较的紧凑遗传算法、简单遗传算法得到的预测均方根偏差平均值分别为0.241、0.289,mCGA具有最小误差。结果表明,采用mCGA进行变量选择,能有效提高模型收敛速度及模型准确度,实现农药含量快速高效的检测。 相似文献
983.
984.
《Journal of Nuclear Science and Technology》2013,50(4):311-315
With the aim of developing a portable system for an in field isotope analysis, we investigate an isotope analysis based on rapid-swept CW cavity ring-down laser spectroscopy, in which the concentration of a chemical species is derived from its photo absorbance. Such a system can identify the isotopomer and still be constructed as a quite compact system. We have made some basic experimental measurements of the overtone absorption lines of carbon dioxide (12C16O2, 13C16O2) by rapid-swept cavity ring-down spectroscopy with a CW infrared diode laser at 6,200 cm?1(1.6)mm). The isotopic ratio has been obtained as (1.07±0.13)x 10?2, in good agreement with the natural abundance within experimental uncertainty. The detection sensitivity in absorbance has been estimated to be 3x 10?8cm?1. 相似文献
985.
C. Lämmel M. Schneider M. Weiser A. Michaelis 《Materialwissenschaft und Werkstofftechnik》2013,44(7):641-649
A comparison between various methods for determining the capacitance and resistance of electrochemical double layer capacitors (EDLC) with cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), galvanostatic charge‐discharge methods and cell voltage jump experiments are presented. Therefore, a commercially available electrochemical double layer capacitor was used. For the validation of the screw cell measurements the electrode foils were isolated and extracted from the commercial capacitor. The results support the adequacy of the screw cell tests for electrode materials on a laboratory scale. The comparison of methods shows in part strong differences. The reasons will therefore be discussed. Consequently, the determination of specific values requires methods which respect the influence of the actual tests or measurement frequency and exhibit the importance of an internationally accepted specification for electrochemical double layer capacitors material investigation. 相似文献
986.
《Ceramics International》2022,48(8):10592-10600
Zinc oxide is widely used in gas sensors, solar cells, and photocatalysts because of its wide bandgap and exciton binding energy of 60 meV in various metal oxides. To use ZnO as a gas sensor, it is necessary to synthesize it with surface defects and a large specific surface area. In this study, hydrothermal synthesis without surfactants was employed to obtain organic-additive-free ZnO. For morphology control, we varied the ratio of the hydroxide ion concentration to the zinc ion concentration. To confirm the growth mechanism of ZnO, we performed X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses. Raman spectroscopy and photoluminescence measurements were performed to analyze the surface properties. The Brunauer–Emmett–Teller method and probe stations were used to measure the specific surface area and sensitivity of the gas sensor, respectively. The results confirmed that flower-shaped ZnO is the most suitable gas-sensing material. 相似文献
987.
Partial isothermal sections at 810, 700 and 585 °C are presented for a high-Al compositional range of Al-Cu-Mo. The maximal solubility of Cu in the Al5Mo phase(s) was found to be ∼3 at.%. The previously reported Al3Ti-type phase was found to be formed around the Al68.5Cu6.5Mo25 composition. The other ternary phase forming in a small compositional range around Al7Cu2Mo has a hexagonal structure with a = 0.86796(8) and c = 1.51948(12) nm. 相似文献
988.
I. Koseva V. NikolovA. Yordanova P. TzvetkovD. Kovacheva 《Journal of Alloys and Compounds》2011,509(25):7022-7026
Investigations are carried out for preparing nanosized pure phase of NaAl(WO4)2 by means of solid state synthesis with mechanical activation, applying the sol-gel method (Pechini) and by co-precipitation. It is shown that it is not possible to obtain pure phase when the initial substances are in stoichiometric amounts due to the simultaneous formation of a number of accompanying tungstate phases. The reasons for their origin are discussed. A method is demonstrated for obtaining a pure phase of NaAl(WO4)2 by co-precipitation of aqueous Na2WO4 and Al(NO3)3 solutions with considerable excess of Na2WO4. It is proved that NaAl(WO4)2 with particle size 40-80 nm is obtained with final synthesis of the powders at temperature 600-650 °C and duration of thermal treatment of 1-2 h. 相似文献
989.
990.
《Optical Materials》2014,36(12):2400-2404
Erbium doped tellurite glasses (TeO2 + Li2O + TiO2) were prepared by conventional melt-quenching method to study the influence of the Er3+ concentration on the luminescence quantum efficiency (η) at 1.5 μm. Absorption and luminescence data were used to characterize the samples, and the η parameter was measured using the well-known thermal lens spectroscopy. For low Er3+ concentration, the measured values are around 76%, and the concentration behavior of η shows Er–Er and Er–OH− interactions, which agreed with the measured lifetime values. 相似文献