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排序方式: 共有368条查询结果,搜索用时 312 毫秒
1.
Single crystal tin nano-rod arrays were fabricated by the electrodeposition method when amphiphilic triblock copolymer P123 was used as a soft template at a concentration much lower than that for forming a liquid crystalline phase.  相似文献   
2.
构筑了MgO部分稳定的ZrO2基固体电解质电化学电池测量EAF的实验装置,测定了Sm2CuO4的标准Gibbs生成自由能。结果表明化合物RE2CuO23(RE=La,Nd,Sm,Eu)随着镧系元素离子半径减小,热力学稳定性下降,并用晶体场理论解释了这一规律。  相似文献   
3.
The variation of ehemiluminescent polarization for reaction Ba(~1S)+N_2O with respect to the Ba beam temperature or the average collision energy E_(rtr) was studied under the single collision condition on beam-gas apparatus. If E_(rtr)<0.06 eV, the distribution of rotational angular momentum for product BaO, i.e. -, increased with the impact energy; while E_(rtr)>0.06 eV, - decreased with the E_(rtr). It is plausible to point out the corresponding relationship between the characteristics of the reaction potential surface and the conformation of the intermediate complexes.  相似文献   
4.
叙述了同步辐射白光全反射X射线荧光分析的实验装置,给出了几种标准物质TXRF实验的检出限,并对实验结果进行了讨论。  相似文献   
5.
A multiplexed microbioreactor system for parallel operation of multiple microbial fermentation is described. The system includes miniature motors for magnetic stirring of the microbioreactors and optics to monitor the fermentation parameters optical density (OD), dissolved oxygen (DO), and pH, in-situ and in real time. The microbioreactors are fabricated out of poly(methylmethacrylate)(PMMA) and poly(dimethylsiloxane)(PDMS), and have a working volume of 150 microl. Oxygenation of the cells occurs through a thin PDMS membrane at the top of the reactor chamber. Stirring is achieved with a magnetic spin bar in the reactor chamber. Parallel microbial fermentations with Escherichia coli are carried out in four stirred microbioreactors and demonstrate the reproducible performance of the multiplexed system. The profiles for OD, DO, and pH compare favourably to fermentations performed in bioreactor systems with multiple bench-scale reactors. Finally, the multiplexed system is used to compare two different reactor designs, demonstrating that the reproducibility of the system permits the quantification of microbioreactor performance.  相似文献   
6.
PrCl3-BaCl2-LiCl三元体系相图的研究   总被引:2,自引:0,他引:2  
本文借助于DTA与X射线结构分析研究了PrCl_3-BaCl_2-LiCl三元体系相同。发现本体系内有对应于PrCl_2、α-BaCl_2、β-BaCl_2、LiCl和Ba_2PrCl_3的五个液相面、六条二次结晶线、一个三元低共熔点E(72.1wt%PrCl_3,2.8wt%BaCl_2,25.1wt%LiCl;441℃)和三元转熔点P(62.5wt%PrCl_3,12.5wt%BaCl_2,25.0wt%LiCi;490℃)。同时发现有一固相下形成的不稳定化合物Y(430℃分解)。  相似文献   
7.
Ag-TiO2 catalysts with different Ag contents were prepared via a sol-gel method in the absence of light. Based on the characterizations of XRD, photoluminescence (PL), surface photovoltage spectroscopy (SPS), field-induced surface photovoltage spectroscopy (FISPS), and XPS as well as the evaluation of the photocatalytic activity for degrading rhodamine B(RhB) solutions, it was found that the Ag dopant promoted the phase transformation as well as had an inhibition effect on the growth of anatase crystallite. The PL and SPS intensities were decreased with increasing Ag content, indicating that the Ag dopant could effectively inhibit the recombination of the photoinduced electrons and holes. However, the active sites capturing the photoinduced electrons reduced, while the Ag content exceeded 5 mol %. At rather low Ag dopant concentrations, the migration and diffusion of Ag+ ions were predominant, while at rather high Ag dopant concentrations, the migration, diffusion, and reduction of Ag ions simultaneously occurred. The Ag-TiO2 photocatalysts with appropriate content of Ag (Ag species concentration is from about 3 to 5 mol %) possessed abundant electron traps so as to be favorable for the separation of the photoinduced electron-hole pairs, which could greatly enhance the activity of the photocatalysts. From the results of FISPS measurements, it could be found that the impurity bands and abundant surface states were introduced into the interfacial layer of TiO2 because of Ag simultaneously doping and depositing, which could improve the absorption capability for visible light of the photocatalysts.  相似文献   
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In this article, various energies and geometries of pure platinum nanoparticles and those of platinum nanoparticles with adsorbed OH were investigated. Fourteen different platinum clusters of 3–40 atoms were studied using spin-unrestricted density functional theory (DFT) with a double numerical plus polarization basis set. This range of sizes gave enough information for establishing the general trends that were the primary goal of the study. Three different shapes of platinum clusters were presented, and the effect of cluster size on binding energy, total energy, and HOMO–LUMO energy gap was investigated. Subsequently, same calculations were performed for those selected Pt clusters with OH adsorbate on the surface. The results show that the stability of both the pure clusters and the clusters with adsorbed OH molecule increases with an increase of cluster size. This fact indicates that direct influence of the size of Pt cluster on the reaction rate is possible, and the understanding of how cluster size would affect binding energy is important. As expected, the effect of cluster size on total energy of molecule was shown to be a linear function independent of cluster type. We also found that optimized (stable) Pt clusters were bigger in size than that of the initial clusters, or clusters with bulk geometry.  相似文献   
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