铝电解中电极湿润性的研究

在微型电解槽上研究了冰晶石——氧化铝熔液对炭电极的湿润性。通入直流电之后,电解质对炭阴极的湿润性变好,同时逐渐在炭板上摊散,甚至脱离阳极,但是它还会逐渐收敛成熔滴,最终重新接上阳极并恢复电解。阴极炭板所吸收的成份,经X-射线鉴定,主要是Na_2AlF_6、NaF、Al_2O_3。电解质对炭阴极的湿润性随电流强度增大和氧化铝浓度增加而改善。但是炭阳极的湿润性,在高电流密度下并非如此。在电解过程中做了变换电极极性的试验,短时间(数秒钟)内使阳极“阴极化”可改善阳极的湿润状态,因而有益于生产。     

铝电解过程中氟污染及治理

1.铝电解工艺简述 铝电解生产过程是以冰晶石——氧化铝熔液做为电解质,炭素材料作为阴、阳极,将直流电从阳极引入电解质,电流通过电解液和铝液层后从阴极导出。电流的作用有二个,一个是将电能以热能的形式保持冰晶石和氧化铝等原料呈熔融状态,第二个是通过电子传递实现电化学反应,使阳极上生成CO和CO_2气体,阴极上析出金属铝,达到炼铝的目的。     

铝电解正常生产过程中的工艺参数探析

现代铝电解工业生产,普遍采用冰晶石-氧化铝电解法,主要设备是电解槽。基本原理是以冰晶石-氧化铝熔体为电解质,碳素材料为阳极和阴极,强大的直流电由阳极导入,经过电解质与铝液层,而后从阴极导出回到电源。通入直流电,一方面是利用它的热能将氧化铝熔化到熔融状态,并保持恒定的电解温度;另一方面是实现电化学反应,也就是使电解质中的铝离子从阴极上得到电子而析出,从而得到铝液,氧离子则在阳极上放电生成二氧化碳和一氧化碳混合气体。     

铝电解槽废旧阴极炭块高温处理前后性质研究

针对铝电解槽废旧阴极炭块,采用MLA方法对高温真空条件处理前后样品进行性质分析研究。结果表明,高温处理后,铝电解槽废旧阴极炭块中大部分杂质被脱除。同时,石墨-冰晶石连生体、石墨-萤石-冰晶石连生体和石墨-NaAl₁₁O₁₇-冰晶石多相连生体热解成石墨炭单体、石墨-冰晶石连生体和新生石墨-霞石连生体。此外,废旧阴极炭块中石墨炭单体从25%增长到约55%,碳纯度为93.55%,NaAl₁₁O₁₇、钠钙硅酸盐、钠铝硅酸盐等13种成分物质脱除率达到100%,FeAlSi脱除率达到95.24%,冰晶石脱除率达到94.41%,钠长石脱除率达到89.47%,石英脱除率达到80%,萤石脱除率也达到69.38%等,说明铝电解槽废旧阴极炭块高温处理后使复杂连生体热解为简单连生体,证明真空蒸馏法能够有效实现铝电解槽废旧阴极炭块的提纯与杂质分离。     

利用Na~+·β-Al_2O_3固体电解质浓差电池测定铝中钠活度

利用 Na~+·β-Al_2O_3 固体电解质组成浓差电池,测量了电解与非电解两种情况下与冰晶石-氧化铝熔体平衡的铅中钠活度。研究了钠活度随熔体温度、分子比、氧化铝浓度及阴极电流密度的变化。实验还表明,电解情况下阴极铝液中的钠活度远大于非电解的静态平衡时铝液中的钠活度。     

铝电解中的界面现象

报道了根据多年的研究所观测到的铝电解中几种重要界面现象,涉及冰晶石-氧化铝熔液中碳电极的湿润与渗透、阳极效应、以及金属在电解液中的溶解损失。讨论了这些界面现象的发生机理问题,特别是静电引力与发生阳极效应的关系。     

金属铝在冰晶石氧化铝熔液中的溶解度测定

研究了金属铝在冰晶石氧化铝熔液中的溶解现象,并通过实验测得铝在通电和不通电两种状态下的溶解度·实验结果表明在通电时铝在冰晶石氧化铝熔液中的溶解度明显减小,认为这是阴极极化所产生的保护作用所致·     

透明电解槽研究铝在冰晶石—氧化铝熔液中的溶解

本文用透明电解槽对金属铝在冰晶石一氧化铝熔液中的溶解及阳极效应进行了直接的观察,铝溶解时先放出大量细小的气泡,然后泛起蓝褐色的金属雾,一定时间后铝为一黑褐色结壳,所包裹熔液重新变清,电解后,金属雾很快消失,一旦停止电解,金属雾便重新从铝液上泛起,阳极效应时阳极上产生一股气流喷向阴极,认为铝的溶解形式主要是电化学溶解,阴极极化(电解)可以使铝的溶解得到抑制,阳极喷射则是由于阳极气体膜电离所致,使得电流效率降低。     

300kA铝电解槽阴极破损机理研究

研究了300 kA大型铝电解预焙槽的阴极破损机理,电解槽停止运行后通过干法剖炉,现场取样分析与观测,研究阴极炭块破损现象,阴极炭块发生断裂、漏眼,表面存在腐蚀坑.由钠渗透、阴极生成碳化铝、电毛细现象、铝和电解质等向阴极炭块缝隙渗透是造成阴极膨胀开裂的原因.分析了影响槽寿命的因素,认为提高阴极质量,加强电解槽启动初期管理,并通过采用石墨化阴极等新材料新技术,不但可降低炉底压降,形成完好的炉帮,而且有效地提高槽寿命.     

铝电解过程中锂元素的阴极渗透机理

铝电解生产过程中，由于氧化铝中含有少量的氧化锂导致电解质中氟化锂含量升高，锂元素向阴极内衬中渗透.通过X射线衍射分析与扫描电镜分析，对电解质和阴极炭块中锂元素的存在形式进行了研究，探讨了铝电解过程中锂元素的阴极渗透机理.结果表明:电解质中的锂主要以LiNa₂AlF₆形式存在；电解过程中，电解质中的部分锂离子被铝还原为金属锂并进入铝液中，铝液中锂摩尔分数与电解质中的氟化锂摩尔分数成正比；电解质中的锂主要以氟化物形式通过阴极炭块中的开气孔和裂缝向阴极炭块中渗透，铝液中的锂不会通过铝液向阴极炭块内部扩散.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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     

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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