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121.
当前忆阻器等效电路中的传统运算放大器存在功耗高、噪声大等问题。针对这些问题,基于简化差分对设计了两种极简化的运算放大器。通过电路仿真对两种简化运算放大器与传统运算放大器进行功耗与噪声仿真分析。结果表明,与三种传统运算放大器相比,该简化运算放大器的功耗最低,抗噪声性能最优。运算放大器的总功耗为15 mW,等效输出噪声电压为11.55 nV·Hz-1/2,噪声系数为35.873 dB。基于两种简化运算放大器,设计了一种二阶荷控忆阻器等效电路。通过理论分析、电路仿真和硬件电路板基实验,对该等效电路的忆阻特性进行了分析与验证。 相似文献
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Dye-sensitized solar cells (DSSCs) are the most promising alternatives to traditional fossil energy because of their advantages of low production cost, facile structure, relatively low environmental impact, relatively high photoelectronic absorption efficiency, and overall high efficiency. In addition, several studies on sensitizers as vital components have been conducted over the last three decades. Compared to metal dyes, metal-free organic dyes have been considered as promising candidates because of their simple fabrication, multiple structures, high molar absorption coefficients, easily tunable properties, and environmental friendliness. In this study, we systematically investigated the optoelectronic properties of six metal-free organic donor-acceptor dyes (RD1–6) derived from the known dye R6 by using the density functional theory (DFT) and time-dependent DFT methods. Cell performance parameters were discussed, including the geometrical and electronic structures, absorption spectrum, adsorption energy, light harvesting efficiency (LHE) curve, predictive short circuit current density (JscPred.), predictive open circuit voltage (VocPred.), and theoretical power conversion efficiency (PCE). Results revealed that all the designed dyes exhibited high theoretical PCE. In particular, dyes RD1, 2, and 4–6 showed greater conjugations, and dyes RD1–3 had smaller energy gaps than those of the reference dye. In addition, dyes RD1–3, 5, and 6 exhibited better light harvesting capacities that covered the entire visible region and extended to the near-infrared region with obviously red-shift maximum absorption wavelengths (λmax), wider LHE curves, and higher JscPred. as compared to the reference dye. It was critical that dyes RD1 and 2 not only have greater conjugations and narrow band gaps but also good light harvesting capacities with more than 56-nm red-shift maximum absorption wavelengths and broadened LHE curves than those of the reference dye. Notably, mainly because of an average increment of 12.0% of JscPred., a remarkable increment of the theoretical power conversion efficiency was observed from 12.6% for dye R6 to 14.1% for dyes RD1 and 2. Thus, dyes RD1 and 2 exhibited superior cell performances and could be promising sensitizer candidates for highly efficient DSSCs. These results could be used to guide effective synthetic efforts in the discovery of efficient metal-free organic dye sensitizers in DSSCs. 相似文献
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In this paper, for a finite group, we investigate to what extent its directed (resp. undirected) reduced power graph determines its directed power graph (resp. reduced power graph). Moreover, we investigate the determination of the orders of the elements of a finite group from its directed (resp. undirected) reduced power graph. Consequently, we show that some classes of finite groups are recognizable from their undirected reduced power graphs. Also, we study the relationship between the isomorphism classes of groups corresponding to the equivalence relations induced by the isomorphism of each of these graphs on the set of all finite groups. 相似文献
129.
流动性约束对我国城镇居民消费影响的实证分析 总被引:1,自引:0,他引:1
根据1978~2007年我国城镇居民消费和收入的相关数据,对我国城镇居民消费和流动性约束之间的关系进行了实证分析,并检验了流动性约束对消费的影响中是否包含了不确定性因素.分析结果表明:我国城镇居民消费受到较强的流动性约束制约;而流动性约束的测度受不确定性影响较小. 相似文献
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利用面板数据模型分析湖南城镇居民的收入与消费之间的关系 总被引:3,自引:0,他引:3
本文利用面板数据模型研究湖南省城镇居民1999-2005年收入与消费之间的关系,分析湖南居民的收入差异对居民消费的影响,为今后调整湖南的消费结构,扩大内需,促进经济发展提供理论依据. 相似文献