Effect of nickel on ion-selective property of rust formed on low-alloying weathering steel

The effect of nickel on the ion-selective property of the rust layers formed on the low alloy weathering steels under marine atmosphere was investigated by an alternate wet-dry accelerated corrosion test.Four types of low-alloying steels with different Ni contents were prepared for the corrosion test.The rust formed at various stages of corrosion was characterized by electrochemical impedance spectra(EIS),electron microprobe analysis(EMPA) and scanning electron microscopy(SEM).Afterwards,the corrosion resistance property of the rust was studied in the light of the experimental results.It is shown that increasing Ni content has significantly improved the corrosion resistance of the low-alloying steels under marine atmosphere.Furthermore,it is noted that an evident cation-selective property emerges in the rust layers with the Ni content of the rust layers up to 1.82%.However,when the Ni content of steel the matrix is below 1.5%,it has little effect on the cation-selective property.The ratio of Ni content in between the rust layer and the steel substrate decreases with the increase of Ni content in the steel substrate and varies little as the corrosion proceeds.     

基于Fluent网格变形的旋流器的形状优化

目前,旋流器的流体结构优化主要局限于单参数的尺寸优化;大多采用多组网格分别模拟的方法;不仅费时,而且对于微小的尺寸变形常常难以操控。当旋流器的分离效率优化到一定峰值后,进一步提高则比较困难。为解决这一问题,提出了基于网格变形的形状优化方法。以旋流器的分离效率为目标,采用ANSYS Fluent的网格变形方法,优化了旋流器的外形结构,将旋流器的分离效率由原来的95.69%提高到了99.18%,并对比分析了优化前后的压降、速度和油相体积分布。研究结果表明：Fluent 网格变形器驱动网格节点的平滑变形,可以同时实现变形区域的结构参数的优化组合,以及优化迭代的自动化和智能化,具有良好的全局搜索能力和较强的鲁棒性;Fluent网格变形优化算法能够缩短CAD建模的时间,避免网格重构;可在单一尺寸优化的基础上,在一定范围内提高旋流器的分离效率。     

Effect of V2O5 addition on the oxidation induration process of Hongge vanadium titanomagnetite pellet

In the present work, the effect of V₂O₅ addition on the oxidation induration process of Hongge vanadium titanomagnetite pellet (HVTMP) was investigated by various characterisation methods. Experimental results showed that with the increase of V₂O₅ addition, the compressive strength of HVTMP decreased and the porosity increased. The V₂O₅ addition had marginal effect on the phase composition, but greatly affected the microstructure during oxidation induration process of HVTMP. The addition of V₂O₅ destroyed the compact structure, located in grain boundary and hindered the haematite recrystallisation, eventually had detrimental effect on the oxidation induration of HVTMP. Besides, a schematic diagram was formulated to describe the oxidation induration mechanism of HVTMP with various V₂O₅ additions. The current study will not only provide experimental evidence to establish a correlation between the V₂O₅ addition and oxidation induration of HVTMP, but also provide both theoretical and technical bases for its effective utilisation in either blast furnace or shaft furnace.     

对医用模拟X线机数字化升级的研究

本文介绍通过医用模拟X线机更换百万像素CCD数字摄像机,产生LVDS标准的数字影像信号,被专业数字采集卡采集后,用工作站进行图像的后处理形成真正的数字图像,完成设备的数字化升级。     

基于超滤处理工艺的洗车废水循环利用技术

以超滤为核心工艺处理洗车废水,对比了采用混凝沉淀-砂滤和单独采用砂滤作为预处理时的出水指标,两种工艺对浊度的去除率分别为99．4％和99．1％,对COD的去除率为69．5％和53．4％,对阴离子表面活性剂（Anionic surfactant,AS）的去除率为69．2％和27．6％。结果表明,采用适合的预处理单元,以超滤为核心的处理工艺在洗车废水循环回用方面具有可行性。     

Optical Spectroscopic Investigation of Ar/CH_3OH and Ar/N_2/CH_3OH Atmospheric Pressure Plasma Jets

Ar/CH3OH and Ar/N2/CH3OH plasma jets were generated at atmospheric pressure by dual-frequency excitations. Two different cases were studied with focus laid on the generation of CN radicals. In one case Ar gas passed through a bubbler with saturated methanol steam but without addition of N2 （Ar/CH3OH plasma）. In the other case N2 passed through the bubbler with saturated methanol steam （Ar/N2/CH3OH plasma）. The optical emission lines of CN radicals have been observed in these two cases of plasma discharges. The addition of N2 can significantly increase the optical emission intensity of CN bands.     

替代定理的研究

教材中的替代定理存在很大的局限性和不完整性,没有考虑：如果被替换支路是受控源的控制电压或控制电流,将如何替代等问题。本文从被替换支路的特点入手,反替代定理分成三种形式加以论述,从而完善了替代定理。     

Electrodeposition of platinum microparticle interface on conducting polymer film modified nichrome for electrocatalytic oxidation of methanol

A simple and “green” approach for fabrication of platinum microparticle interface on conducting polymer film modified nichrome matrix (Pt/PAn/Nc) for methanol oxidation was investigated. The Pt microparticles were grown directly on the polyaniline precursor film modified nichrome matrix (PAn/Nc) in dilute chloroplatinic acid solution by cyclic voltammetry. The SEM revealed that the deposits were composed of spherical Pt microparticles. Cyclic voltammetry and chronoamperometry were used for characterization of the electrode properties. Results showed that the spherical Pt/PAn/Nc electrode enhanced the catalytic activity and promoted methanol electrooxidation. The catalytic activity of Pt/PAn/Nc electrode was 15 times higher than that obtained from pure platinum under the same conditions. Moreover, the deposited Pt microparticles improved the electrochemical properties of nichrome and reduced the dosage of noble metal platinum, remarkably. The cost could be reduced dramatically by decreasing the contents of platinum. The Pt/PAn/Nc are likely a promising electrocatalyst for methanol electrooxidation.     

基于标准水资源指数(SWRI)的流域水文干旱评估——以海河北系为例

构建了一个新的水文干旱评估指标——标准水资源指数(SWRI),结合分布式水循环模型、Copula函数及统计检验等方法,形成了一套完整的水文干旱识别、评估及特征分析的基本框架。以海河北系为例,定量识别了1956—2009年间的水文干旱事件,并对其干旱特征及变化规律进行了剖析。结果表明:海河北系近54年发生的34次水文干旱主要集中在短历时、低强度、小面积区间内,空间上主要分布在张家口、大同及北京等地区;干旱指标的联动关系上,干旱历时、强度与面积指标间呈显著的线性或指数相关关系,90%的水文干旱历时低于40个月、干旱面积占比不超过43%,干旱强度低于9.0;在给定的干旱特征指标值(如干旱面积)条件下,另一干旱指标值越大(如强度越大)干旱发生概率越小,且存在明显的特征区间;单变量水文干旱重现期介于联合重现期和同现重现期之间。     

纳米白炭黑的应用及其制备方法

系统地描述了纳米白炭黑在各领域中的应用,并介绍了现有的几种纳米白炭黑的制备方法,如气相法、溶胶凝胶法、微乳液法等,分析了各种方法所制备产物的特点及其存在的问题,并对纳米白炭黑的研究进行了展望。