碳钢在硫酸溶液中的钝化和振荡

研究了碳钢电极在硫酸溶液中的钝化和电流振荡行为。发生振荡的电位范围仅在钝化电位附近。振荡电流反映了电极活化、钝化过程的交替变化,其大小、周期和峰宽都随着溶液 H_-~+离子浓度改变而变化。振荡电流的形状亦与 H_-~+离子浓度有关。振荡原因是钝化膜的结构和组成的不均匀,它反复地生成和溶解,使电极表面交替钝化和活化,致使电流振荡。     

用丝束电极研究NaNO2对钢铁防护性能的影响

采用丝束电极多电极电化学法研究钢铁在不同浓度的NaCl溶液中的电位变化，并分析NaN02的加入对体系电位的影响和NaN02对钢铁的防护作用。研究结果表明：钢铁在NaCl溶液中的电位分布在一定的电位区间，各丝电极的电位存在差异，各区域金属的腐蚀不均匀；随着溶液中NaCl含量从1％增大至5％，丝束电极的电极电位平均值从—0．43V变为-0．54v，电极电位负移，金属腐蚀倾向增大：由于NaNO2和钢铁电极表面的腐蚀产物Fe^2＋的相互作用并生成保护性的薄膜，在NaCl溶液中加入NaNO2将使体系电极电位明显正移：加入NaNO2后各丝电极电位的分布是随机的、不均匀的，且电位分布区间增大，表明所形成的保护性薄膜不均匀。     

氯离子诱导的镍在硝酸溶液中的电流振荡

报道了氯了子诱导的镍在0．5mol.dm^-2硝酸溶液中活化－钝化过渡区电流振荡，在恒电位条件下，随着氯离子浓度的升高或者电极电位的降低，电流振荡由周期性振荡逐渐向非周期性振荡转变，根据实验结果，对该体系的电流振荡机理进行了讨论。     

硫铁矿烧渣制备聚合硫酸铁新工艺

硫铁矿烧渣是硫酸制备过程中产生的固体废弃物．将硫铁矿烧渣与硫酸混合后,经过熟化、水溶、过滤得到酸性硫酸铁溶液．在硫酸铁溶液中,加入新制备的氢氧化铁,于25～60℃时反应2h后加入少量双氧水得到聚合硫酸铁(PFS)．随着氢氧化铁与硫酸铁溶液反应的进行,溶液中PFS盐基度不断增加．当硫酸铁的量一定时,PFS盐基度随氢氧化铁的量增加而增加．温度升高时有利于PFS的生成．加入双氧水将溶液中的Fe     

HCO_3~-/CO_3~(2-)浓度对X70管线钢钝化行为的影响

采用动电位扫描法、循环伏安法研究了X70管线钢在不同浓度的NaHCO3 /Na2 CO3 溶液中的钝化行为。结果表明 ,材料在该体系中具有明显的钝化现象 ,随溶液浓度升高 ,X70钢钝化变得困难。利用Parkins的边界条件 ,确定了X70钢在 1mol/LNaHCO3 0 5mol/LNa2 CO3 溶液中发生应力腐蚀开裂的敏感电位区间为 - 5 6 0～ -6 5 0mV。X70钢在钝化过程中表面发生的反应比较复杂 ,电极过程包含Fe的阳极溶解、生成钝化膜、钝化膜的化学溶解三种过程。用X 射线衍射分析了X70钢在活化钝化过渡区表面钝化膜的组成 ,证实了对电极过程的分析     

苯并三氮唑在铁电极上的光谱电化学研究

苯并三氮唑在硫酸溶液中吸附在铁电极上的极化曲线和表面拉曼光谱研究结果表 明：苯并三氮唑同时抑制了铁的阳极溶解反应和阴极析氢反应;当电位负于腐蚀电位时,苯并三 氮唑以分子或质子化的形式吸附于电极表面．     

可控微环境下阴离子对铁／硫酸体系阳极溶解过程的影响

将流动注射技术与半封闭电极相结合,研究了硫酸根离子、氯离子和柠檬酸根离子对铁／硫酸体系阳极溶解过程的影响．在恒电位极化过程中,向电极／溶液界面分别注射含以上3种离子的溶液,通过比较注射不同溶液时的电化学行为,分析3种阴离子对铁阳极溶解过程的影响机理．氯离子具有吸附性和侵蚀性,电位较低时,更多地表现为吸附性,电位较高时,更多地表现为侵蚀性;柠檬酸根离子具有缓蚀性,能够吸附在电极表面,抑制铁在硫酸溶液中的腐蚀;硫酸根离子则对铁的阳极溶解过程影响不大．实验结果表明,流动注射技术与半封闭电极相结合是研究金属腐蚀的一种有效新方法．     

Fe/ 硼酸盐缓冲溶液界面性质的交流阻抗研究

结合线性电位扫描、开路计时电位和交流阻抗技术研究了Fe在硼酸盐缓冲溶液(pH=8．4)中不同电位区间的界面性质．在氮气气氛下，电位低于-0．77V，界面发生析氢反应，反应受电子转移步骤控制。同时存在氢原子的表面吸附过程；-0．77V至0．60V间，Fe氧化成2价Fe而发生活性溶解，同时2价Fe进一步氧化成3价Fe，二步反应均受电子转移步骤控制；至0．60V，形成具有保护作用的单层Fe304；-0．60V至-0．50V间，Fe氧化成2价Fe的反应随电位升高而变慢，表现为负的反应电阻；-0．50V至0．90V间，Fe进入钝化区，较低电位下主要是Fe304转化成Fe2O3的过程，受电子转移步骤和0H^-在钝化膜中的扩散步骤混合控制，较高电位下Fe直接氧化成3价Fe。受电子转移步骤和3价Fe离子在钝化膜中的扩散步骤混合控制；电位高于0．90V，界面发生析氧反应和氧化膜溶解，反应受电子转移步骤控制，反应过程中有中间产物吸附．     

聚苯胺电极的制备及其电化学聚合的影响因素

采用1mol／L硫酸作为介质，扫描速度为100mV／s．扫描电位为-0．2～0．8V，用循环伏安法在纳米二氧化钛（Nano-TiO2）膜电极上实现了苯胺的电化学聚合。结果表明复合膜的生成、峰电流的大小受溶液浓度、扫描速度以及扫描电位的影响，成膜速度随溶液浓度增大而加快，但膜稳定性降低，峰电流随扫描速度和电位增大而提高，可逆性降低．     

有机膦酸防垢剂对CaCO_3溶液动电性质的影响

为了探讨有机膦酸防垢剂的防垢机理,将等量的CaCl2溶液和Na2CO3溶液混合,适时测定了加入不同有机膦酸防垢剂时CaCO3生成过程中的Zeta电位,并与加入EDTA的实验进行了比较.结果表明,CaCO3表面带有负电,反应刚开始时Zeta电位变化较快,30 min后趋于稳定;生成过程中加入有机膦酸防垢剂会使碳酸钙表面Zeta电位绝对值变小.最后,从配位化学及胶体化学的角度对实验结果进行了分析,认为加防垢剂后Zeta电位的变化对防垢作用有利.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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