The third order optical nonlinear character of ZnSe nanocrystals doped silica glasses

ZnSe/SiO₂ composites were fabricated with conventional sol–gel synthesis method. The absorption spectra of the semiconductor-doped glasses (SDGs) were presented and compared among different ZnSe doping amounts. The energy gap (E _g) decreased distinctly as the content of ZnSe QDs increased. Nonlinear refractive indexes were measured by single beam Z-scan technique. The results revealed that the third order nonlinear susceptibility was efficiently affected by E _g, which was explained by local field effect and Kramers–Kronig (KK) relation.     

基于模型的网络控制系统传输特性分析

目前以太网在工业网络控制系统中已得到广泛应用，这里，通过对其MAC子层控制方式的数据传输模型分析，从考虑实际各节点之间差异性的角度，结合工业网络的特性要求，提出了一种分析网络控制系统的方法和思路，推导出了一些对分析和设计网络控制系统有一定指导意义的计算公式。     

Sandwich,Vertical‐Channeled Thick Electrodes with High Rate and Cycle Performance

3D thick electrode design is a promising strategy to increase the energy density of lithium‐ion batteries but faces challenges such as poor rate and limited cycle life. Herein, a coassembly method is employed to construct low‐tortuosity, mechanically robust 3D thick electrodes. LiFe_0.7Mn_0.3PO₄ nanoplates (LFMP NPs) and graphene are aligned along the growth direction of ice crystals during freezing and assembled into sandwich frameworks with vertical channels, which prompts fast ion transfer within the entire electrode and reveals a 2.5‐fold increase in ion transfer performance as opposed to that of random structured electrodes. In the sandwich framework, LFMP NPs are entrapped in the graphene wall in a “plate‐on‐sheet” contact mode, which avoids the detachment of NPs during cycling and also constitutes electron transfer highways for the thick electrode. Such vertical‐channel sandwich electrodes with mass loading of 21.2 mg cm^?2 exhibit a superior rate capability (0.2C–20C) and ultralong cycle life (1000 cycles). Even under an ultrahigh mass loading of 72 mg cm^?2, the electrode still delivers an areal capacity up to 9.4 mAh cm^?2, ≈2.4 times higher than that of conventional electrodes. This study provides a novel strategy for designing thick electrodes toward high performance batteries.     

低频涡流电磁场复值变分问题分析

首先给出了电机似稳涡流场复矢量边值问题的数学提法,在分析复矢量场有关理论的基础上,给出了与似稳涡流场复矢量边值问题等价的变分问题。最后,针对目前涡流场复矢量边值问题研究中存在的一些问题作了探讨,指出了这些问题的错误所在。     

三相不平衡配电网不确定性分布式电源运行域仿射求解算法

高不确定性分布式电源(DG)的大量并网,给配电网安全、可靠运行带来了极大挑战。DG运行域可为DG的接入位置提供参考依据,并可实时监控配电网的运行安全,实现预警和预防性控制。提出了一种三相不平衡配电网中不确定性DG运行域的仿射求解算法。利用基于仿射算术的潮流计算求取节点电压关于DG出力不确定变量的近似线性表达式,综合考虑馈线容量、反向潮流以及电压表达式的安全范围等约束条件,构建三相不平衡配电网的DG运行域的优化求解模型,继而求取配电网中各DG的运行域边界。通过对改进的IEEE 123三相不平衡系统进行仿真,并与近似精确的仿真逼近法进行对比,验证了所提求解算法的准确性及高效性。     

Engineering the Exciton Dissociation in Quantum‐Confined 2D CsPbBr3 Nanosheet Films

Recent years have witnessed a rapid development of all‐inorganic halide perovskite in optoelectronic devices. Ultrathin 2D CsPbBr₃ nanosheets (NSs) with large lateral dimensions have demonstrated exceptional photophysical properties because of their analogous exciton electronic structure to quantum wells. Despite the incredible progress on device performance, the photophysics and carrier transportation parameters of quantum‐confined CsPbBr₃ NSs are lacking, and the fundamental understanding of the exciton dissociation mechanism is far less developed. Here, a ligands rearrangement mechanism is proposed to explain why annealed NS films have an increased charge transfer rate and a decreased exciton binding energy and lifetime, prompting tunneling as a dominant way of exciton dissociation to separate photogenerated excitons between neighboring NSs. This facile but efficient method provides a new insight to manipulate perovskite nanocrystals coupling. Moreover, ultrathin 2D CsPbBr₃ NS film is demonstrated to have a enhanced absorption cross section and high carrier mobility of 77.9 cm² V^?1 s^?1, contributing to its high responsivity of 0.53 A W^?1. The photodetector has a long‐term stability up to three months, which are responsible for reliable perovskite‐based device performance.     

几种钢框架-支撑结构体系的特点和性能

钢框架-支撑体系具有良好的抗震性能和较大的抗侧刚度.介绍了中心支撑、偏心支撑及消能支撑等钢框架-支撑体系的构造和性能,通过比较,指出偏心支撑框架具有良好的耗能能力,消能支撑框架具有较强的抗侧钢度,是理想的抗侧力体系.     

基于数据库的电气设备故障诊断智能系统

文章阐述了电站电气主设备基于数据库技术、模糊理论、人工智能专家系统及神经网络原理构造的故障诊断系统。在系统实现中,用隶属函数反应故障现象特征的模糊性和模糊关系,基于关系数据库进行知识的模糊表达,用模糊性更新传播算法实现基于规则的模糊推理,以人工神经网络实现基于示例的学习,统一以专家系统进行诊断过程管理。并以实例证明了系统的正确性和实用性。     

基于互联网的全站仪检定数据处理平台的开发

结合我院现有计量检定业务管理系统,基于安卓系统设计全站仪检定数据处理系统手机app,利用蓝牙无线传输技术,实现了全站仪检定数据的自动输入、自动处理等功能,以及检定记录的无纸化存储,极大地降低了计量检定人员的工作量.