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随着光催化研究的深入开展,人们对复合催化剂的内部电子空穴转移路径产生了浓厚的兴趣,并提出几种相对合理的载流子迁移路径猜想.其中包括异质结构型(包括Type-Ⅰ型异质结与Type-Ⅱ型异质结)和Z-Scheme构型(包括直接Z-Scheme型异质结和间接Z-Scheme型异质结),解释了部分活性提升的机理.我们选取了全固态Z-Scheme异质结结构作为模型,制备出TiO2-C-C3N4三元复合催化剂.全固态Z-Scheme异质结结构是指在两个带隙匹配的半导体之间引入导电材料,半导体之间不直接接触.在太阳光的激发下,导电材料两侧的半导体被同时激发,电子分别从两者的价带跃迁至导带,并在价带上留下空穴.由于两者之间存在电子导体,处于中间位置的导带电子会沿电子导体运动,与处于中间位置价带的空穴复合,留下氧化还原能力较强的价带空穴和导带电子.整个反应路线形成"Z"字形状,模拟了光合作用的反应路径.我们对TiO2-C-C3N4三元催化剂以及TiO2... 相似文献
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Hole mobility changes under uniaxial and combinational stress in different directions are characterized and analyzed by applying additive mechanical uniaxial stress to bulk Si and SiGe-virtual-substrate-induced strained- Si(s-Si)p-MOSFETs(metal-oxide-semiconductor field-effect transistors)along 110 and 100 channel directions. In bulk Si,a mobility enhancement peak is found under uniaxial compressive strain in the low vertical field.The combination of 100 direction uniaxial tensile strain and substrate-induced biaxial tensile strain provides a higher mobility relative to the 110 direction,opposite to the situation in bulk Si.But the combinational strain experiences a gain loss at high field,which means that uniaxial compressive strain may still be a better choice.The mobility enhancement of SiGe-induced strained p-MOSFETs along the 110 direction under additive uniaxial tension is explained by the competition between biaxial and shear stress. 相似文献
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《金沙水韵》是中央电视台制作的三十三集大型电视纪录片《再说长江》中的一集,该片在2007年度国家广电总局电视节目技术质量金帆奖的评比中获得电视声音制作纪录片类一等奖。本文着重介绍了在录制《金沙水韵》过程中,声音录制遇到的问题及解决办法,同时对《再说长江》的整体录音工作进行简要介绍。 相似文献
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研究分数阶微分方程多点分数阶边值问题解的存在性与唯一性,利用不动点定理,得到了边值问题存在唯一解和至少存在1个解的充分条件. 相似文献
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Atmospheric effects have significant influence on the performance of a free-space optical continuous variable quantum key distribution (CVQKD) system. In this paper, we investigate how the transmittance, excess noise and interruption probability caused by atmospheric effects affect the secret-key rate (SKR) of the CVQKD. Three signal wavelengths, two weather conditions, two detection schemes, and two types of attacks are considered in our investigation. An expression aims at calculating the interruption probability is proposed based on the Kolmogorov spectrum model. The results show that a signal using long working wavelength can propagate much further than that of using short wavelength. Moreover, as the wavelength increases, the influence of interruption probability on the SKR becomes more significant, especially within a certain transmission distance. Therefore, interruption probability must be considered for CVQKD by using long-signal wavelengths. Furthermore, different detection schemes used by the receiver will result in different transmission distances when subjected to individual attacks and collective attacks, respectively. 相似文献