Charge/discharge characteristics of sulfur composite cathode materials in rechargeable lithium batteries

The charge and discharge characteristics of lithium batteries with sulfur composite cathodes have been investigated. The sulfur composites showed novel electrochemical characteristics. The analysis of the differential capacity indicated that the discharge process showed two voltage plateaus of 2.10 V and 1.88 V, and the charge process also presented two voltage plateaus of 2.22 V and 2.36 V. The overcharge test showed that the composite cannot be charged over 4.0 V, the voltage always stopped at about 3.9 V during charging, indicating that the composite presented the intrinsic safety for the overcharge of lithium batteries. The overcharge can cause serious safety problem for the conventional Li-ion batteries. The overcharge test also showed that the batteries with sulfur composite were destroyed when the upper cut-off voltage was over 3.6 V. However, the composite presented good reversible capacity after it was deep discharged even to 0 V. It showed stable cycleability and high cycling capacity of 1000 mAh g⁻¹ when cycling between 0.1 V and 3.0 V, indicative of the different characteristic from the conventional oxide cathode materials. The prototype polymer battery with the composite cathode material presented the energy density of 246 Wh kg⁻¹ and 401 Wh L⁻¹.     

大学生党支部建在班上的实践与思考

以漳州师范学院为例,总结了党支部建在班上的实践经验,并对大学生班级党支部的设置方式、工作模式和内涵建设进行了思考.     

清代大运河之帆船航运

自中国封建王朝定都北京以来,连接北京和杭州的大运河一直作为水上要道发挥着重要作用。特别是在明清两代,大运河作为最重要的漕运通路,承担了江南税粮输送的任务。可以说,从某种意义上看,大运河与北京政权的命运息息相关。但到目前为止,这些承担输送任务的漕船到底如何在大运河上航行的问题,仍然不甚清晰。因此,以清代的档案史料为中心,来分析运河漕船的航行情况。     

基于复制技术的电力自动化系统容错模型的实现

从提高电力自动化系统的可靠性、安全性和实时性出发,在建立的基于复制技术的电力自动化系统容错模型的基础上,详细地介绍了系统模型的实现方法.设计的容错系统在三机表决系统的基础上,对系统结构和表决算法上进行了一定的改进,具有较强的容错性,为坚强、自愈的智能电网中的电力自动化系统的建设提供了参考意见.     

基于jQuery的动态虚拟场景技术研究

介绍了X3D(eXtensible 3D)虚拟现实技术的特点,分析了使用SM修改虚拟场景的方法.在分析Ajax技术在X3D虚拟现实系统开发中使用现状及存在问题的基础上,提出将jQuery库引入到X3D虚拟系统开发过程中.该方法通过与SAI(scene access interface)的结合,实现了虚拟场景的动态加载和更新,有效提高了系统的开发效率.最后给出了相关应用实例.     

LTE系统中切换算法的研究

为了提高LTE系统越区切换的性能,寻求一种能够提高LTE系统性能的最优切换算法。分别对基于RSRP测量、基于RSRP和RSRQ测量、以及基于RSRQ测量等自适应算法的三种切换算法进行了研究。通过三种算法的分析比较,发现基于RSRQ测量的自适应算法能够减少切换次数并且保证服务质量,因此该算法是一种可以提高LTE系统性能的最优切换算法。     

关于AOE网中关键路径求解算法的研究

介绍AOE网中关键路径的相关概念,通过算法描述和实例,探讨基于拓扑排序求解、P矩阵的求解和广度优先搜索遍历（BFS）方法三种算法,求解AOE网中关键路径的实现过程,并进一步从算法的时间复杂度、数据结构形式及实现的容易程度等几方面分析三种求关键路径算法的优劣。     

楼板对钢筋砼异形柱框架破坏机制的影响分析

采用基于柔度法的纤维模型梁柱单元,对按现行混凝土异形柱结构技术规程设计的异形柱框架结构,分别按考虑和忽略现浇楼板及其钢筋对梁抗弯能力的增强作用2种情况,分别进行了单向水平罕遇地震输入下的空间结构弹塑性动力分析。对比分析结果表明,现浇楼板及其钢筋将提高框架梁的抗弯能力,从而改变罕遇地震作用下混凝土异形柱结构的破坏模式,对于高烈度区混凝土异形柱结构影响尤为明显,因此该类结构在抗震设计中必须考虑现浇楼板及其钢筋的影响。     

三氯甲烷萃取——毛细管气相色谱法测定维生素B12生产废水中的丙酸

维生素B12生产产生的废水中含有大量可回收的丙酸,对废水中丙酸的测定进行了研究,建立了测定丙酸的三氯甲烷萃取——气相色谱方法,方法的结果表明:检出限为5×10-2mg/L,精密度RSD为1.32%,加标回收率为97.2%—103.3%。     

Optimal operation of distillation processes under uncertain inflows accumulated in a feed tank

A new method of optimizing the operation of distillation processes with uncertain inflow streams from upstream plants is discussed. The case considered is the streams that will be first accumulated in a tank before feeding to the column. To minimize the total amount of operating energy while keeping a stable column operation under these inflows, a novel decomposed optimization strategy consisting of two steps was used. For an optimal planning of the dynamic operation, a smooth feed flow policy to the column is developed in the first step by stochastic optimization under chance constraints by ensuring a predefined probability of holding the tank level inside the desired range. An easy-to-use method developed computes the maximum reachable probability of holding the constraints so that a feasible solution of the chance constrained problem can be guaranteed. Since the uncertainty in the inflow stream variability is absorbed in the stochastic optimization over the tank, the operation of the dowstream distillation column is deterministic. Therefore, in the second step, the reflux and reboiler duty policies of the column are developed by deterministic dynamic optimization. The optimal overall strategy is obtained by the maximized smoothness of the feed flow to the distillation column. The approach is applied to a pilot column, and the developed operating policies are implemented on the real plant by experiment.