氨水降膜吸收传热传质强化的研究进展

综述了近年来应用于氨水降膜吸收性能强化的研究成果,总结了氨水降膜吸收的强化方法,分析了氨水降膜吸收过程中的影响因素,指出研究中的一些不足,并对该领域未来的研究方向进行了讨论,指出采用物理处理、化学处理和纳米技术三种强化手段相结合的方法是未来强化吸收可能的发展趋势。     

漫透射成像法激光强度时空分布测量装置

 提出用CCD漫透射成像法测量激光强度时空分布和激光功率,给出了测量原理, 简要叙述了装置总体结构,介绍了测量装置各部分,给出了散射屏的散射特性,重点分析了光路布局、镜头焦距、光圈、景深、滤光片的参数选择,介绍了数据处理软件,给出了激光强度分布测量实验结果。结果表明：漫透射成像法测量激光强度时空分布是可行的,该装置测量强度分布分辨力高达5 mm;测量功率准确、可靠,测量不确定度小于6%,使用方便,实现了在小空间内对大光斑进行功率和强度分布的同时准确测量。     

Optical out-of-plane spin polarization and charge conductivities in spin-orbit-coupled systems in the presence of an in-plane magnetic field

Out-of-plane spin and charge responses to the terahertz field for a clean two-dimensional electron gas with a Rashba spin-orbit interaction in the presence of an in-plane magnetic field are studied. We show that the characteristic optical spectral behavior is remarkably different from that of the system in the absence of in-plane magnetic fields. It is found that the optical spin polarization normal to the plane is nonzero even for this clean system, in sharp contrast to the static case. Due to the combined effect of spin-orbit coupling and in-plane magnetic field, both diagonal and off-diagonal components of optical charge conductivity tensor are nonvanishing. It is indicated that one can control the spin polarization and the optical current by adjusting the optical frequency. In addition, the out-of-plane spin polarization and conductivities strongly rely on the direction of the external magnetic field. Nevertheless, they meet different angle-dependent relations. This dynamical out-of-plane spin polarization could be measured by the time-resolved Kerr rotation technique.     

High open-circuit voltage organic solar cells enabled by a difluorobenzoxadiazole-based conjugated polymer donor

A new polymer donor based on 3,3′-difluoro-2,2′-bithiophene(2F2T) and difluorobenzoxadiazole(ffBX), named 2F2T-ffBX, is designed and synthesized. The organic solar cell(OSC) based on 2F2T-ffBX donor and [6,6]-phenyl-C60-butyl acid methyl ester([60]PCBM) acceptor exhibits a high efficiency of 7.3% with a high open-circuit voltage(V_(oc)) of 1.03 V. When blended with perylenediimide-based acceptor(PDI6), the corresponding OSC shows a higher V_(oc) of 1.19 V with a low energy loss of 0.50 e V but a much lower efficiency of 2.0%. The detailed analyses including charge generation, transport, recombination properties, and morphology were performed to understand the performance of corresponding devices.     

聚甲基丙烯酸甲酯间隔的金纳米立方体与金膜复合结构的表面增强拉曼散射研究

金属纳米颗粒与金属薄膜的复合结构由于其局域表面等离子体和传播表面等离子体间的强共振耦合作用,可作为表面增强拉曼散射(SERS)基底,显著增强吸附分子的拉曼信号.本文提出了一种聚甲基丙烯酸甲酯(PMMA)间隔的90 nm金纳米立方体与50 nm金膜复合结构的SERS基底,通过有限元方法数值模拟,得到PMMA的最优化厚度为15 nm.实验制备了PMMA间隔层厚度为14 nm的复合结构,利用罗丹明6G (R6G)为拉曼探针分子, 633 nm的氦氖激光器作为激发光源,研究了复合结构和单一金纳米立方体的SERS效应,发现复合结构可以使探针分子产生比单一结构更强的拉曼信号.在此基础上,研究了不同浓度金纳米立方体水溶液条件下复合结构中R6G的拉曼光谱.结果表明,当金纳米立方体水溶液浓度为5.625μg/mL的条件下复合结构中R6G的拉曼信号最强,且可测量R6G的最低浓度达10~(–11) mol/L.     

Exceptionally Long C−C Single Bonds in Diamino‐o‐carborane as Induced by Negative Hyperconjugation

The synthesis of a series of 1,2‐diamino‐o‐carboranes ( 1 – 4 ) is reported. The molecular structures of these diamino‐o‐carboranes are remarkable as the inner‐cluster C?C bonds are all ultra‐long (162.7–193.1 pm) and vary substantially with small variations in the substituents. The results of quantum mechanical investigations suggest that the origin of the bond elongation is significant in‐plane negative hyperconjugation of lone pairs of the nitrogen substituents with the σ* orbitals of the C?C bonds in o‐carboranes.     

Nickel‐Catalyzed 1,1‐Alkylboration of Electronically Unbiased Terminal Alkenes

An unprecedented nickel‐catalyzed 1,1‐alkylboration of electronically unbiased alkenes has been developed, providing straightforward access to secondary aliphatic boronic esters from readily available materials under very mild reaction conditions. The regioselectivity of this reaction is governed by a unique pyridyl carboxamide ligated catalyst, rather than the substrates. Moreover, this transformation shows excellent chemo‐ and regio‐selectivity and remarkably good functional‐group tolerance. We also demonstrate that under balloon pressure, ethylene can also be utilized as a substrate. Additionally, competence experiments indicate that selective bond formation is favored at the α‐position of boron and preliminary mechanistic studies indicate that the key step in this three‐component reaction involves a 1,2‐nickel migration.     

Flower-like Cu5Sn2S7/ZnS nanocomposite for high performance supercapacitor

Due to the synergistic effect between ZnS and Cu₅Sn₂S₇, the ZnS can enhance electrochemical performance of pristine Cu₅Sn₂S₇.     

基于拓扑优化设计的宽频吸波复合材料

本文基于拓扑优化方法设计并制备了一种宽频吸波复合材料,该吸波复合材料由高强玻璃纤维透波板、电阻损耗型超材料、聚氨酯泡沫和碳纤维反射板组成.仿真及测试结果表明,该吸波复合材料在2–18 GHz频段内的平板反射率均小于-12 dB.并且由于采用高强玻璃纤维及碳纤维复合材料作为面板层,聚氨酯泡沫作为芯材,因此该吸波复合材料不仅在较宽频带内对电磁波具有高的吸收率,同时还具有质量轻、耐高温、耐低温、耐湿热、抗腐蚀等特点,便于实现吸波与力学性能及耐环境性能的兼容,具有一定的工程应用价值.     

基于扩展单粒子模型的锂离子电池参数识别策略

为了精确识别电动汽车锂离子动力电池的关键状态参数,基于多孔电极理论和浓度理论,建立了一种考虑液相动力学行为的锂离子电池扩展单粒子模型.相较于传统单粒子模型,该模型增加了对负电极表面固体电解质界面膜参数的描述,并考虑了温度和液相浓度变化对锂离子电池关键参数的耦合影响.基于所建立的扩展单粒子模型,提出一种简化的参数灵敏度分析方法和有效的锂电池参数识别策略,用以确定特定工况下的高灵敏度待识别参数,进而利用遗传算法实现参数的优化求解.最后,通过对比分析本文模型和传统单粒子模型的仿真输出电压和相同工况下电池的实验输出电压验证了提出模型和参数识别方法的有效性和可行性,为电池管理系统的健康状态估计提供了理论基础.