完善农村合作金融产权制度对策探讨

产权制度改革是实现农村合作金融改革的核心,其目标是建立有效的产权制度。本文运用规范分析与实证分析相结合的方法,首先阐述了产权制度效率的涵义及衡量标准,进而深刻剖析我国农村信用社产权制度缺陷,最后提出完善农村合作金融产权制度效率的若干建议

Hollow micro/nanostructures metal oxide as advanced anodes for lithium-ion batteries

电动汽车和智能电网的快速发展对锂离子电池提出了更高的要求,即在拥有高能量密度和高功率密度的同时,兼有快速充放电和较高的安全性能。电极材料是电池性; 能的关键,金属氧化物因为拥有较高的比容量和安全性能,已经成为有希望替代传统商用石墨负极的新型电极材料。然而,金属氧化物负极的循环结构稳定性较差、; 电导率低,由此导致差的循环及倍率性能,极大地阻碍了其商业化应用。近年来,拥有微纳米空心结构的金属氧化物显示出了优异的电化学性能。本文介绍了制备空; 心结构金属氧化物的常用方法,讨论了各种方法的优缺点,并列举了常见空心结构金属氧化物作为锂离子电池负极时的性能表现,最后对空心结构金属氧化物未来的; 发展方向和发展前景予以展望。More efforts are needed to upgrade the performances of lithium-ion; batteries (LIBs) for their further applications in various large; electrical appliances such as electric vehicles and smart grid as these; devices require high capacity, power density, high rate capability and; especially safety. Electrode materials are the key to the performance of; LIBs. Recently, metal oxides with much higher capacities and better; safety have the prospect of becoming alternative anode materials of; commercial graphite. However, the intrinsic low charge/ionic; conductivity and poor cycling structural stability lead to poor cycling; and rate performances, which greatly hinder their commercial; applications. To overcome these disadvantages of metal oxide anodes for; LIBs, several strategies have been developed during the past decade.; Among them, metal oxide hollow micro-nanostructures exhibit excellent; electrochemical properties as anode material for LIBs. In this review,; we first describe the current commonly preparation methods to synthesize; metal oxide hollow structures and comment on their advantages and; shortages. According to some typical examples, we show the promising use; of metal oxides hollow-structured anode materials for LIBs. Finally, the; direction and prospect of metal oxide hollow micro-nanostructures using; as anode materials are further discussed.国家重点研究计划纳米科技重点专项; 国家自然科学基金; 福建省自然科学基金项目; 厦门大学校长基

X射线双星系统的探测

搜寻X射线双星并建立大规模样本是解决众多科学问题(如\"银河系中有多少黑洞X射线双星?黑洞和中子星之间有无质量间隙?球状星团中有无黑洞?\"等)的基础.爱因斯坦探针卫星拥有更灵敏的探测能力,将在运行的几年之中,预计可以发现一批新的中子星和黑洞X射线双星,研究其空间和动力学质量分布成为解决上述问题的关键.国家重点研发计划(编号:2016YFA040080X);;国家自然科学基金(编号:1133305);;中国科学院战略性先导科技专项(编号:XDA15052100,XDB23040000)资助项

Transition from tunneling leakage current to molecular tunneling in single-molecule junctions

数十年来，半导体工业一直遵循基于“摩尔定律”所设定的发展蓝图，逐步提升集成电路芯片上晶体管的集成度和运行速度，减小器件尺寸。为探索这一尺寸极限，课题组基于机械可控裂结技术自主开发了具有飞安级电学测量和亚纳米级位移控制灵敏度的科学仪器，在国际上首次获取了一系列具有不同重复单元的寡聚苯乙炔类分子电导随电极间距的演变关系，并发现随着电极间距的缩小，器件电输运由通过分子器件电流占主导逐步转变到由隧穿漏电流占主导。对于本研究中具有最小尺寸的寡聚苯乙炔分子器件，其由于隧穿漏电流所制约的尺寸极限可小至0.66 nm，预示了有机分子器件在未来电子器件小型化方面具有重要的应用潜力。 这一研究工作是在化学化工学院洪文晶教授、萨本栋微纳研究院杨扬助理教授以及英国Durham University的MartinR. Bryce教授共同指导下完成的。能源材料化学协同创新中心iChEM Fellow刘俊扬博士为论文第一作者，博士研究生郑珏婷、李瑞豪和硕士研究生黄晓艳、唐永翔、皮九婵、本科生王飞等参与了研究工作。田中群教授、毛秉伟教授和师佳副教授为论文工作提供了重要指导。【Abstract】The tunneling leakage current will be a major quantum obstacle during miniaturization in the semiconductor industry down to the scale of several nanometers. At this scale, to promote charge transport and overcome the tunneling leakage current between the source and drain terminals, molecular electronic junctions offer opportunities by inserting molecules between these two electrodes. Employing a series of oligo(aryleneethynylene) (OAE) molecules, here we investigate the transition from tunneling leakage current to molecular tunneling in the single-molecule devices using mechanically controllable break junction (MCBJ) technique, and the transition distances of the OAE molecular junctions were determined and even down to 0.66 nm for OAE2 molecular junction, which demonstrates that the intrinsic charge transport properties of a single-molecule device can be outstripped from the tunneling leakage current. Consequently, molecular electronic devices show the potential to push the ultimate limit of miniaturization to the scale of several angstroms.This work was supported by the National Key R&D Program of China (2017YFA0204902). This work was also generously supported by the Young Thousand Talent Project of China, the EC FP7 ITN “MOLESCO” project number 606728, the National Natural Science Foundation of China (nos. 21703188, 21673195, 21503179), and the China Postdoctoral Science Foundation (2017M622060). 该工作获得科技部国家重点研发计划课题（2017YFA0204902），国家自然科学基金委（21673195、21703188、21503179）以及中国博士后科学基金（2017M622060）等项目的资助，也得到了固体表面物理化学国家重点实验室、能源材料化学协同创新中心的支持