Physical and Electrochemical Properties of Doped LiFePO4 as Cathode Material for Lithium-Ion Batteries

LiFePO4 cathode material was synthesized by a solid-state reaction using doping several elements (Nb5 ,Zr4 ). The starting materials were mixed with a high-efficient sander and treated thermally under flowing N2. The samples were characterized by X-ray diffraction (XRD), field-emission gun electron microscopy (FEG), and their electrochemical performance was investigated in the term of cycling behavior. Room temperature discharge capacity about 140.6 mA·h·g-1 was obtained at C/5 rate.     

钻孔嵌岩灌注桩承载特性试验研究

钻孔嵌岩灌注桩已成为高层建筑较常用的基础形式之一．在南昌地区某工程中，通过对钻孔灌注桩进行静载试验，分析研究了钻孔嵌岩灌注桩的承载特性和荷载传递机理，对此类桩的侧摩阻力与端阻力的问题进行了探讨。     

Consideration on Effective Diffusivity of Strontium in Granite

Abstract

Diffusive behavior of strontium and certain kinds of divalent cations in Inada granite were studied by a through-diffusion method. In order to examine the effect of sorption onto overall diffusive behavior, two kinds of solutions were used: 0.1M KCl solution and deionized water. The effective diffusion coefficient (D_e ) and rock capacity factor (a) were (2.0–3.6) xl0–¹³ m²/s and less than 0.022 in 0.1M KCl solution and (0.32–1.7) x 10 ^?13m²/s and 1.5–2.4 in deionized water respectively. The D_e , and α in deionized water were much larger than those in 0.1M KCl solution. These results are well explained by taking into account the diffusion of sorbed ion or the surface diffusion. In support of this mechanism, most D_e , values of Sr reported for various rocks are found proportional to the sorptivity ( _ρR_d )-In the case that the sorptivity is low, D_e of Sr depends on porosity like that of nonsorbed iodide. The effective diffusion coefficient of Sr in rocks was well explained by taking into account pore and surface diffusion and was expressed as D_e=2.1 xl0^?10 _? ^1.3+3.5xl0″^?12 _ρR_d . The effective diffusion coefficient of divalent cations in the granite was found proportional to their diffusion coefficients in bulk solution.     

DHDECMP-TBP/煤油萃取 HNO_3-稀土过程中防止形成第二有机相的研究

研究了ＤＨＤＥＣＭＰ－ＴＢＰ／煤油萃取ＨＮＯ３后形成和防止形成第二有机相的各影响因素。以Ｇｄ代表稀土，探讨了ＤＨＤＥＣＭＰ－ＴＢＰ／煤油萃取稀土时ＤＨＤＥＣＭＰ浓度、ＴＢＰ浓度、水相ＨＮＯ３浓度和温度对有机相萃取负载量的影响。结果表明：０．６０ｍｏｌ／ＬＤＨＤＥＣＭＰ－１．４０ｍｏｌ／ＬＴＢＰ／煤油能有效避免第二有机相的形成，又能满足工艺负载量的要求。     

水资源承载力综合评价的熵权属性识别模型

根据水资源承载力分析的结构特点,在传统多目标分析决策技术的基础上,将熵值法与属性识别模型相结合,建立了基于熵权的属性识别水资源承载力评价模型,应用熵值法来确定权重系数,避免了权重系数确定的主观性问题,用一种新的方法进行水环境承载力评价.结合实际应用的结果表明,其评价结果合理,适用于水环境承载力评价.     

短消息指标新定义及在事务信道限制中的应用

短消息指标可以度量隐蔽信道的短消息传输能力,是信道容量的必要补充.但指标现有定义中还存在着以下问题:消息长度参数在普通信息系统中不能定量分析;信道限制机制难以同时满足传输时间和保真度两个约束;没有包含消息的敏感度信息.针对这些问题,首先通过引入短消息传输价值的概念,给出了短消息指标的新定义.在该定义中,利用价值阈值统一表示系统对信道短消息传输能力的容忍程度,并且在所采用的价值函数中引入了消息的敏感度因素.其后,基于安全实时数据库应用场景给出了结合短消息指标和信道容量的事务隐蔽信道度量和限制机制.理论分析和模拟结果表明,基于短消息指标的新定义,系统可以对隐蔽信道威胁实施全面的度量和可调节的限制.     

受水流冲刷影响后的吸力桶基础水平极限承载力

以某海域海上风机吸力桶基础为研究对象,采用Abaqus有限元数值模拟软件,考虑基础在不同土层中由水流冲刷导致其周围土体缺失时吸力桶基础的水平承载力。结果表明,桶内土体的缺失对吸力桶水平承载力的影响不大,随着吸力桶基础外周围土体缺失的扩大,其水平承载力逐渐降低,并影响海上风机的正常使用。     

非晶Mg65-xNi21Pr14Agx合金电极的制备及其放电性能

用铜模喷铸法制备了非晶Mg65-x Ni21-Pr14Ag x合金,采用球磨方法细化了合金颗粒。系统研究了不同Ag含量对非晶合金电极充放电行为、放电容量、循环稳定性、高倍率放电等性能的影响规律。结果表明,Ag元素的添加改善了合金电极充/放电性能,随着Ag含量的增加,非晶合金电极的最大放电容量和循环稳定性均呈现先增大后减小的规律,其高倍率放电性能也有所提高,适量Ag的添加可明显改善非晶MgNi-Pr系合金的放电性能。     

国内外环氧树脂的生产现状及应用进展

本文阐述国内外环氧树脂发展动向及应用进展。     

刨煤机的刨运速比选型

本文分析各类刨煤机在不同刨运速比下的运煤能力利用率,讨论刨运速比的最佳选择。