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排序方式: 共有192条查询结果,搜索用时 46 毫秒
41.
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Qian Xinming Zhang Xintong Bai Yubai Li Tiejin Tang Xinyi Wang Erkang Dong Shaojun 《Journal of nanoparticle research》2000,2(2):191-198
-Fe2O3 single crystal thin films have been prepared from 45nm diameter colloid. These thin nanocrystalline films exhibit a typical behavior of n-type semiconductor material because of the anodic photocurrent generation. The anodic photocurrent response upon illumination and the reversal spike of cathodic current upon the light switched off suggests that the electrons can flow in both directions and no space charge layer exists at the thin film/electrolyte interface. The decreased photocurrent responses of thicker films can be explained by the electric resistance effect and recombination effect. Moreover, the thicker film will lead to a poor photocurrent response for short wavelength light. Considering the use of sunlight, the thin film thickness should be controlled to an optimal value. 相似文献
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The strain gradient plasticity theory is used to investigate the crack-tip field in a power law hardening material. Numerical
solutions are presented for plane-stress mode I and mode II cracks under small scale yielding conditions. A comparison is
made with the existing asymptotic fields. It is found that the size of the dominance zone for the near-tip asymptotic field,
recently obtained by Chen et al., is on the order 5% of the intrinsic material lengthI. Remote from the dominance zone, the computed stress field tends to be the classical HRR field. Within the plastic zone only
force-stress dominated solution is found for either mode I or mode II crack. 相似文献
45.
含铜/镍金属酶的成熟需要一系列的铜/镍金属伴侣蛋白,这些铜/镍金属伴侣蛋白分别参与铜或者镍的转运,对维持细胞体内铜/镍金属平衡至关重要,同时金属酶完成金属催化活性中心的组装也依赖于这类伴侣蛋白。近年来关于铜/镍金属蛋白的研究取得可喜的进展,这些研究为进一步认识体内铜/镍平衡体系提供了重要依据。本文首先简要地介绍铜的摄取和细胞内平衡体系,接着着重介绍三个重要的铜转运蛋白Atox1、Cox17和CCS关于结构和功能的进展,以及这些铜转运蛋白和药物相互作用的机理。然后详细介绍在氢化酶和脲酶成熟路径中参与了镍的摄取、调节、转运和存储,维持细胞内镍金属平衡的镍伴侣蛋白,并介绍了脲酶、氢化酶这两条成熟路径之间的联系。 相似文献
46.
Hao Lv Yaoming Ding Aimei Liu Jufang Tong Xunong Yi Qianguang Li Xinming Wang 《Journal of Polymer Science.Polymer Physics》2013,51(21):1529-1532
We present an approach to an analysis of the chromatic aberrations of gradient refractive index polymeric rod lens. Two kinds of materials system are used in this study: diallyl phthalate‐methyl methacrylate and diethylene glycol bis(allyl carbonate)‐poly (1,1,5‐trihydroperfluoropentyl methacrylate). The results of a numerical simulation reveal that the chromatic aberration of the focal length, the longitudinal, and lateral chromatic aberrations depend on the ratios between the change in periodic length caused by wavelength and the periodic length. By reducing the ratios, the chromatic aberration of focal length, the longitudinal and lateral chromatic aberrations at any lens length are decreased effectively. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013 , 51, 1529–1532 相似文献
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ChenYaosong(陈耀松);MaXinming(马新民);LiangGouping(梁国平);DaiMing(戴民)(ReceivedMay23,1994;CommunicatedbyDaiShiqiang)SHEARINGFLOWNEARAB... 相似文献
49.
Changlin Ding Meiling Huang Genxiang Zhong Lijun Liu Xinming Huang 《Crystal Research and Technology》2014,49(6):405-413
For the seed‐assisted casting process for silicon ingots, different partition blocks were designed in the directional solidification (DS) furnaces to preserve the seed crystals and optimize the thermal field in the hot‐zone. A transient global model was established to investigate the effects of different partition blocks during the solidification process. The simulation results showed that the partition blocks can significantly influence the temperature distributions and the melt flow fields. From the designed partition blocks, the movable partition block was more favorable for the seed‐assisted DS process. A suitable temperature gradient and a flat seed‐melt (s‐m) interface were obtained, which facilitated the preservation of seed crystals effectively, and an optimized crystal‐melt (c‐m) interface was achieved as well. One of the designs of the movable partition blocks was implemented in quasi‐mono crystalline silicon casting experiments and it has been confirmed that the designed movable partition block was helpful for the improvement of the single crystal area. 相似文献
50.
A short and efficient synthesis of 1-(3-tert-butyl-1-phenyl-1H-pyrazol-5-yl)-3-(5-(2-morpholinoethoxy)-2H-chromen-8-yl) urea derivatives (1a–c), a novel type of p38 MAPK inhibitors, is described. The Claisen thermal rearrangement of arylpropargyl ethers was employd as a key step to synthesize the chromene core. The solvent effect on the ratio of the resultant two isomers of Claisen thermal rearrangement, namely 2-methylbenzofuran and 2H-chromen, was also investigated. 相似文献