An electrochemical impedance spectroscopic study of the electronic and ionic transport properties of LiCoO2 cathode

The storage behavior and process of the first delithiation-lithiation of LiCoO2 cathode were investigated by electrochemical impedance spectroscopy(EIS). The electronic and ionic transport properties of LiCoO2 cathode along with variation of electrode potential were obtained in 1 mol·L?1 LiPF6-EC:DMC:DEC electrolyte solution. It was found that after 9 h storage of the LiCoO2 cathode in electrolyte solu-tions,a new arc appears in the medium frequency range in Nyquist plots of EIS,which increases with increasing the storage time. In the charge/discharge processes,the diameter of the new arc is reversi-bly changed with electrode potential. Such variation coincides well with the electrode potential de-pendence of electronic conductivity of the LiCoO2. Thus this new EIS feature is attributed to the change of electronic conductivity of LixCoO2 during storage of the LiCoO2 cathode in electrolyte solutions,as well as in processes of intercalation-deintercalationtion of lithium ions. It has been revealed that the reversible increase and decrease of the resistance of SEI film in charge-discharge processes can be also ascribed to the variation of electronic conductance of active materials of the LiCoO2 cathode.     

电子商务——现代企业发展必由之路

阐述了企业应用电子商务的必要性,分析了适合企业的主流电子商务应用模式,对目前企业电子商务发展和应用提出了一些建议。     

500kV输电线路施工管理数字化的实现

简述了地理信息系统的基本特点及其功能,介绍了500kV输电线路施工管理地理信息系统的工程设计及实现途径。     

基于GPRS的电子衡器无线网络接口设计

提出了将GPRS无线模块嵌入电子衡器,实现电子衡器远程管理,并给出了具体的设计。     

电子商务支付发展趋势——3D-Secure技术

从协议模型、工作机制及优势等方面对3D-Secure技术进行了分析和探讨。     

从数据加密谈电子商务安全

基于经典数据加密方法DES与RSA,讨论电子商务安全技术和SET协议。     

浅论信息时代电子文件的管理

从档案管理的角度出发,分析了电子文件产生的条件、途径、现状及制约因素,初步探讨了电子文件的有效管理模式,认为电子文件与纸制文件共存互动是现阶段档案管理的必由之路,档案管理人员应有效利用两种文件的特点.实现全面、科学的文件管理战略.     

轻型电喷汽油车稳态工况的排放特性

为了研究电喷汽油车运行工况对排放物的影响规律,利用底盘测功机和定容取样方法,测试了稳态下各排放物的浓度,计算了排放因子,分析了车速、载荷和挡位对排放因子的影响。研究结果表明:CO、HC和NOx排放因子大体上随车速的升高而降低,但在高挡、高速时CO和NOx排放因子略有回升,HC排放因子变化不大,CO排放因子随载荷的增大略有升高,HC和NOx排放因子基本没有变化;排放因子随挡位的变化与车速有关,低速时采用低挡排放因子较低,但在高速时应采用高挡;不同运行工况下催化转化器的转化效率也是影响排放因子的因素之一。     

On the Effects of Central Japan Expressway＇s Commuter Toll Discount Policy in Nagoya Area

Road pricing policies have two equally important objectives that have to be considered： the optimal use of the road network and the fiscal sustainability for the management of the network. The aim of this work is to examine the effects on these two objectives of a recent pricing policy implemented in Japan＇s expressway networks. Recently the Nippon （Japan） Expressway Companies （NEXCO, operators of Japan＇s nation wide expressway network） have implemented several toll discount policies for users equipped with electronic toll collectors （ETCs）. One of the policies is the commuter discount policy that discounts 50% for a journey on the NEXCO expressway no longer than 100 km during the commuting peak hours. This paper examines its effect on congestion reduction in the road network of Nagoya area and its influence on the use of expressways operated by another major local public expressway company in Nagoya. The congestion easing effect of this policy is compared with a potential marginal cost pricing scheme. These observations suggest that policy coordination regarding toll levels is needed for expressway corporations and transportation authorities for improving transportation efficiency of utilization of the whole network.     

EDA技术在电子技术设计中的应用

电子设计自动化已成为当今世界电子设计的潮流，电路专用仿真软件Multisim2001是迄今为止使用最方便、最直观的电路仿真设计软件。向学生介绍EDA技术，在电子技术课程设计中应用Multisim2001设计软件，让他们尽快掌握先进的设计方法，跟上时代的步伐。满足社会对高新技术人才的需要。