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41.
This paper introduces the petrological, mineralogical and geochemical fea. tures of the rocks hosting the Sareshik tin deposit—an independent tin deposit related to Hercynian A-type granites discovered in China in 1987. A comparison with the features of A-type granites at home and abroad indicates that some of their petrological features are more typical than those of famous A-type granites of Nigeria. The geological features of the tin deposit are salient and notably different from those of some famous tin deposits in China, so the deposit may represent China's deposits associated with anorogenic granites. This tin deposit was formed in the Hercynian Stage. This type of tin deposit was for the first time discovered in China and is also rare in the world. It is a new type of tin deposit in China. 相似文献
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The clasto-plastic constitutive behaviors of continuous fiber reinforced composites under cyclic loadings are studied by the micromechanics method in which the equal-strain model is used in the fiber direction, the equal-stress model in the other directions. It is supposed that fiber is linearly elastic and matrix is clastic-viscoplastic. The constitutive equations of the matrix are described by Bodner-Partom's unified constitutive theory. Boron/Aluminum composite, as an example, is investigated in detail for an understanding of the stress-strain relations and initial yield behaviors of metal matrix composites. Present results are compared with the experimental data.The project was supported by the Chinese National Natural Science Foundation. 相似文献
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大宽高比的非轴对称带状电子注在微波和毫米波真空电子器件中具有显著的技术优势与应用潜力. 采用轴向均匀磁场可以聚焦和传输带状电子注,且具有易于实现电子注与磁场的匹配和调节、聚焦强流电子注以及无传输截止电压限制等优点,但面临严重的Diocotron不稳定性. 结合单粒子模型理论和冷流模型理论,对带状电子注传输特性进行的研究及其数值计算表明,通过详细设计带状注电子光学系统物理参数,增强聚焦磁场并在传输通道高度方向上选择较大的电子注填充比,可以有效降低Diocotron不稳定性对带状电子注的影响,并实现其长距离稳
关键词:
带状电子注
传输
均匀磁场聚焦
Diocotron不稳定性 相似文献
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利用平平加作为表面活性剂, 正戊醇作为助表面活性剂, 环己烷作为油相, 以硫化钠(Na2S)和醋酸锌(Zn(Ac)2)作为反应物, 通过控制反应条件在反相胶束体系中合成出单分散的ZnS纳米球与纳米梭. 采用XRD和TEM对产物的结构和形貌进行表征, 结果表明产物均为六方相ZnS, 晶胞参数为a=0.3823 nm, c=56.2 nm, 纳米球直径约为50 nm, 纳米梭直径约为60 nm, 长度约为110 nm. 采用UV-Vis(紫外可见吸收光谱)和PL(荧光光谱)研究了产物的光学性能. 纳米球的紫外可见光谱的吸收峰出现在288 nm处, 而纳米梭在305 nm处有强吸收峰, 与块体材料相比, 分别有约60和50 nm的蓝移. 当激发波长为270 nm时, 纳米球和纳米梭产物分别能够发出波长为408和303 nm的紫外光. 相似文献
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Hao-Yue Guan Yu-Fei Feng Bai-Hao Sun Jian-Zhao Niu Qing-Sheng Zhang 《Molecules (Basel, Switzerland)》2022,27(15)
N-nitrosamines, which are well-known pro-mutagens, are found in drugs, pickled food and tobacco. Therefore, controlling their concentrations is very important. When an HPLC, GC or NMR analysis is conducted to investigate certain asymmetrical N-nitrosamines, two sets of signals attributed to the asymmetric N-nitrosamine isomers are usually observed. However, few reports on the NMR assignment of asymmetrical N-nitrosamine isomers have been published. In this study, we investigated the NMR assignments of the Z/E isomers of six asymmetrical N-nitrosamines by means of density functional theory (DFT) calculations. The configuration of the major isomer of asymmetrical N-nitrosamine 3 was the Z-configuration. The configuration of the major isomers of asymmetrical N-nitrosamines 4–7 was the E-configuration. Then, we determined the Z/E ratios of these asymmetrical N-nitrosamines by means of variable temperature (VT) and room temperature (RT) 1H-NMR experiments. The ratios of the Z/E isomer 3 quickly increased beyond 100% in the VT 1H NMR experiments. The ratios of Z/E isomers 4–7 were increased in the range of 10–60% in the VT 1H NMR experiments. The results of this study indicate that identifying the isomers of asymmetrical N-nitrosamine is necessary to control the quality of N-nitrosamines for active pharmaceutical ingredients (APIs). 相似文献
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水杨酸的光电离和光激发机理 总被引:1,自引:0,他引:1
水杨酸(SA)是阿司匹林的主要有效成分,具有多种医疗疗效如美容和抗癌作用.本研究运用激光闪光光解瞬态吸收技术,考察了在266 nm激光的激励条件下水杨酸的光物理和光化学行为.实验结果表明,在266 nm的激光作用下SA可发生单光子电离,量子产率为0.21,光致电离效率较高.在细胞含氧体系中,由SA光电离生成的水合电子易与O2结合生成超氧阴离子自由基,可杀灭癌细胞.SA光电离产生的阳离子自由基可以脱质子生成中性自由基,测得其pKa是2.95.用SO-4誗0自由基氧化SA,获得了具有390 nm特征吸收的SA+誗,测得SO-4誗0氧化SA的反应速率常数为2.28×109 L.mol-1.s-1,进一步验证了SA光电离反应机理.同时发现SA可能受266nm激光激发生成激发三线态(3SA*),转而有可能生成单线态氧(1O2*).这些结果为水杨酸作为一种潜在的抗肿瘤药物提供了依据. 相似文献
47.
We grow InN epilayers on different interlayers by metal organic vapour phase epitaxy (MOVPE) method, and investigate the effect of interlayer on the properties and growth mode of InN films. Three InN samples were deposited on nitrided sapphire, low-temperature InN (LT-InN) and high-temperature GaN (HT-GaN), respectively. The InN layer grown directly on nitrided sapphire owns the narrowest x-ray diffraction rocking curve (XRC) width of 300 aresee among the three samples, and demonstrates a two-dimensional (2D) step-flow-like lateral growth mode, which is much different from the three-dimensional (3D) pillar-like growth mode of LT-InN and HT-GaN buffered samples. It seems that mismatch tensile strain is helpful for the lateral epitaxy of InN film, whereas compressive strain promotes the vertical growth of InN films. 相似文献
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Wei Xiang-Fu Zhu Qing-Sheng Guo Jing-Dong Shang Jian-Ku 《Journal of Solid State Electrochemistry》2022,26(1):171-181
Journal of Solid State Electrochemistry - The high throwing power (TP) value is one of the most important parameters for the Cu electroplating of through-holes in flexible printed circuit (FPC). It... 相似文献