第八届欧洲铁电学会议(EMF—8)和第一届欧洲集成铁电体会议(EMIF—1)于1995年7月3～8日在荷兰University of Ni-jmegen同时举行。 笔者参加了EMF—8和EMIF—1两个会议,交叉听取了相关报告,并与到会的中、外学者进行了比较广泛的交谈。...第八届欧洲铁电学会议(EMF—8)和第一届欧洲集成铁电体会议(EMIF—1)于1995年7月3～8日在荷兰University of Ni-jmegen同时举行。 笔者参加了EMF—8和EMIF—1两个会议,交叉听取了相关报告,并与到会的中、外学者进行了比较广泛的交谈。下面就笔者感兴趣的几个问题作一归纳介绍。当然介绍中可能有片面性,也可能会挂一漏万,需要进一步了解这两届会议详情的读者。展开更多
第8届国际集成铁电会议(International Symposium On Integrated Ferroelectrics)于1996年3月17—20日在美国亚利桑那州的TEMPE市举行。与会代表250人,他们来自14个国家和地区。会上发表论文近150篇。利用铁电体材料研制器件的设想早在5...第8届国际集成铁电会议(International Symposium On Integrated Ferroelectrics)于1996年3月17—20日在美国亚利桑那州的TEMPE市举行。与会代表250人,他们来自14个国家和地区。会上发表论文近150篇。利用铁电体材料研制器件的设想早在50年代就有人提出。铁电体材料具有存储信息、压电效应、热释电效应等独特优点,只是采用的体材料本身固有的一些缺点和困难不能满足制作实际器件的要求。近几年来,各国尤其是美、日投入了相当的力量开发铁电薄膜的应用,取得了极大的进展。展开更多
第9届国际铁电学会议(The 9th International Meeting on Ferroelectricity,简记为IMF-9)于1997年8月24～29日在韩国汉城市Swiss Grand Hotel召开。大会收到论文摘要1000余篇,来自33个国家的850余名科技人员出席了会议。国际著名铁电学...第9届国际铁电学会议(The 9th International Meeting on Ferroelectricity,简记为IMF-9)于1997年8月24～29日在韩国汉城市Swiss Grand Hotel召开。大会收到论文摘要1000余篇,来自33个国家的850余名科技人员出席了会议。国际著名铁电学家J.F.Scott教授在"铁电学研究回顾及展望"的特邀报告中指出,在过去几十年中,铁电学(包括铁电物理、材料和器件)的研究取得了重要的进展,特别是铁电软模理论、非正常铁电体(improper ferroelectrics)、弛豫性铁电体以及集成铁电薄膜等的研究,对促进铁电学的发展起到重要作用。他还概括了本届会议上几个引人注目的进展,包括利用第一原理计算立方钙钛矿结构材料的结构相变,薄膜的外延生长,铁电应用(包括多层膜、光学器件应用)等,并指出铁电薄膜方面的进展尤为重要。人们可以期望,铁电学研究,将作为一个新的颇富成效的领域,进入21世纪。会议决定,下届国际铁电学会议,将于2001年在西班牙召开。展开更多
The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its...The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors,which is crucial for preserving spin coherence and enhancing integration density.Hence,two-dimensional(2D)Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable.Herein,by employing first-principles calculations,we design a thermodynamically stable 2D Rashba semiconductor,YSbTe_(3),which possesses an indirect band gap of 1.04 eV,a large Rashba constant of 1.54 eV·Åand a strong electric field response of up to 4.80 e·Å^(2).In particular,the Rashba constant dependence on the electric field shows an unusual nonlinear relationship.At the same time,YSbTe_(3)has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier(~0.33 eV per formula).By changing the electric polarization direction,the Rashba spin texture of YSbTe_(3)can be reversed.These out-standing properties make the ferroelectric Rashba semiconductor YSbTe_(3)quite promising for spintronic applications.展开更多
The electrochemical oxidation behavior of pyrite in bioleaching system of Acidthiobacillusferrooxidans was investigated by cyclic voltammetry （CV）, polarization curve and electrochemical impedance spectroscopy （EIS...The electrochemical oxidation behavior of pyrite in bioleaching system of Acidthiobacillusferrooxidans was investigated by cyclic voltammetry （CV）, polarization curve and electrochemical impedance spectroscopy （EIS）. The results show that in the presence or absence of A. ferrooxidans, the oxidation reaction of pyrite is divided into two steps： the first reaction step involves the oxidation of pyrite to S, and the second reaction step is the oxidation of S to SO4^2-. The oxidation mechanism of pyrite is not changed in the presence of A. ferrooxidans, but the oxidation rate of pyrite is accelerated. With the extension of reaction time of A. ferrooxidan with pyrite, the polarization current density of pyrite increases and the breakdown potential at which the passive film dissolves decreases. The impedance in the presence ofA. ferrooxidans is obviously lower than that in the absence of A. ferrooxidans, further indicating that microorganism accelerates the corrosion process of pyrite.展开更多
The effect of electroslag refining on iron reduction from commercial aluminum was investigated.Cast electrodes of commercial aluminum were electroslag refined using KCl-NaCl-Na3AlF6 slag containing Na2B4O7.Experimenta...The effect of electroslag refining on iron reduction from commercial aluminum was investigated.Cast electrodes of commercial aluminum were electroslag refined using KCl-NaCl-Na3AlF6 slag containing Na2B4O7.Experimental results indicate that the iron content decreases with increasing Na2B4O7 addition and remelting time,and the iron content decreases from 0.400% to 0.184% under 9% Na2B4O7 addition for 30 min remelting.The elastic modulus,yield strength and ultimate tensile strength commercial aluminum are improved,and the tensile elongation is increased by 43% after electroslag refining.The chemical reaction between melt and slag to form Fe2B is the main reason for iron reduction and the thermodynamic calculation of the chemical reaction theoretically accounts for the formation of Fe2B.展开更多
Bioleaching and electrochemical experiments were conducted to evaluate marmatite dissolution in the presence of pure S.thermosulfidooxidans.The effects of particle size,p H controlling and external addition of Fe^3＋ ...Bioleaching and electrochemical experiments were conducted to evaluate marmatite dissolution in the presence of pure S.thermosulfidooxidans.The effects of particle size,p H controlling and external addition of Fe^3＋ ions on the zinc extraction were investigated.The results show that in the bioleaching process the best particle size range is 0.043-0.074 mm and adjusting p H regularly to the initial value has a profound effect on obtaining high leaching rate.External addition of Fe^3＋ ions could accelerate the bioleaching,while the concentration of additional Fe^3＋ over 2.5 g/L weakens the positive effect,and even hinders the dissolution of marmatite.SEM and XRD analyses of the leaching residues reveal that a product layer composed of elemental sulfur and jarosite is formed on the mineral surface,which results in a low leaching speed at later phase.The results of electrochemical measurements illustrate that additional Fe^3＋ ions could increase the corrosion current density,which is favorable to zinc extraction.The EIS spectra show that rate-limiting step does not change when Fe^3＋ ions are added.展开更多
文摘第八届欧洲铁电学会议(EMF—8)和第一届欧洲集成铁电体会议(EMIF—1)于1995年7月3～8日在荷兰University of Ni-jmegen同时举行。 笔者参加了EMF—8和EMIF—1两个会议,交叉听取了相关报告,并与到会的中、外学者进行了比较广泛的交谈。下面就笔者感兴趣的几个问题作一归纳介绍。当然介绍中可能有片面性,也可能会挂一漏万,需要进一步了解这两届会议详情的读者。
文摘第8届国际集成铁电会议(International Symposium On Integrated Ferroelectrics)于1996年3月17—20日在美国亚利桑那州的TEMPE市举行。与会代表250人,他们来自14个国家和地区。会上发表论文近150篇。利用铁电体材料研制器件的设想早在50年代就有人提出。铁电体材料具有存储信息、压电效应、热释电效应等独特优点,只是采用的体材料本身固有的一些缺点和困难不能满足制作实际器件的要求。近几年来,各国尤其是美、日投入了相当的力量开发铁电薄膜的应用,取得了极大的进展。
文摘第9届国际铁电学会议(The 9th International Meeting on Ferroelectricity,简记为IMF-9)于1997年8月24～29日在韩国汉城市Swiss Grand Hotel召开。大会收到论文摘要1000余篇,来自33个国家的850余名科技人员出席了会议。国际著名铁电学家J.F.Scott教授在"铁电学研究回顾及展望"的特邀报告中指出,在过去几十年中,铁电学(包括铁电物理、材料和器件)的研究取得了重要的进展,特别是铁电软模理论、非正常铁电体(improper ferroelectrics)、弛豫性铁电体以及集成铁电薄膜等的研究,对促进铁电学的发展起到重要作用。他还概括了本届会议上几个引人注目的进展,包括利用第一原理计算立方钙钛矿结构材料的结构相变,薄膜的外延生长,铁电应用(包括多层膜、光学器件应用)等,并指出铁电薄膜方面的进展尤为重要。人们可以期望,铁电学研究,将作为一个新的颇富成效的领域,进入21世纪。会议决定,下届国际铁电学会议,将于2001年在西班牙召开。
基金supported by the National Natural Science Foundation of China(22322304,22273092,22373095)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450101)+2 种基金the Innovation Program for Quantum Science and Technology(2021ZD0303306)the USTC Tang ScholarThe authors wish to acknowledge the Supercomputing Center of the USTC for providing computational resources.
文摘The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors,which is crucial for preserving spin coherence and enhancing integration density.Hence,two-dimensional(2D)Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable.Herein,by employing first-principles calculations,we design a thermodynamically stable 2D Rashba semiconductor,YSbTe_(3),which possesses an indirect band gap of 1.04 eV,a large Rashba constant of 1.54 eV·Åand a strong electric field response of up to 4.80 e·Å^(2).In particular,the Rashba constant dependence on the electric field shows an unusual nonlinear relationship.At the same time,YSbTe_(3)has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier(~0.33 eV per formula).By changing the electric polarization direction,the Rashba spin texture of YSbTe_(3)can be reversed.These out-standing properties make the ferroelectric Rashba semiconductor YSbTe_(3)quite promising for spintronic applications.
基金Project (2010CB630903) supported by the National Basic Research Program of China
文摘The electrochemical oxidation behavior of pyrite in bioleaching system of Acidthiobacillusferrooxidans was investigated by cyclic voltammetry （CV）, polarization curve and electrochemical impedance spectroscopy （EIS）. The results show that in the presence or absence of A. ferrooxidans, the oxidation reaction of pyrite is divided into two steps： the first reaction step involves the oxidation of pyrite to S, and the second reaction step is the oxidation of S to SO4^2-. The oxidation mechanism of pyrite is not changed in the presence of A. ferrooxidans, but the oxidation rate of pyrite is accelerated. With the extension of reaction time of A. ferrooxidan with pyrite, the polarization current density of pyrite increases and the breakdown potential at which the passive film dissolves decreases. The impedance in the presence ofA. ferrooxidans is obviously lower than that in the absence of A. ferrooxidans, further indicating that microorganism accelerates the corrosion process of pyrite.
基金Project (50825401) supported by the National Natural Science Foundation of ChinaProject (2012CB61905) supported by the National Basic Research Program of China
文摘The effect of electroslag refining on iron reduction from commercial aluminum was investigated.Cast electrodes of commercial aluminum were electroslag refined using KCl-NaCl-Na3AlF6 slag containing Na2B4O7.Experimental results indicate that the iron content decreases with increasing Na2B4O7 addition and remelting time,and the iron content decreases from 0.400% to 0.184% under 9% Na2B4O7 addition for 30 min remelting.The elastic modulus,yield strength and ultimate tensile strength commercial aluminum are improved,and the tensile elongation is increased by 43% after electroslag refining.The chemical reaction between melt and slag to form Fe2B is the main reason for iron reduction and the thermodynamic calculation of the chemical reaction theoretically accounts for the formation of Fe2B.
基金Project(2010CB630903)supported by the National Basic Research Program of ChinaProject(51374249)supported by the National Natural Science Foundation of China
文摘Bioleaching and electrochemical experiments were conducted to evaluate marmatite dissolution in the presence of pure S.thermosulfidooxidans.The effects of particle size,p H controlling and external addition of Fe^3＋ ions on the zinc extraction were investigated.The results show that in the bioleaching process the best particle size range is 0.043-0.074 mm and adjusting p H regularly to the initial value has a profound effect on obtaining high leaching rate.External addition of Fe^3＋ ions could accelerate the bioleaching,while the concentration of additional Fe^3＋ over 2.5 g/L weakens the positive effect,and even hinders the dissolution of marmatite.SEM and XRD analyses of the leaching residues reveal that a product layer composed of elemental sulfur and jarosite is formed on the mineral surface,which results in a low leaching speed at later phase.The results of electrochemical measurements illustrate that additional Fe^3＋ ions could increase the corrosion current density,which is favorable to zinc extraction.The EIS spectra show that rate-limiting step does not change when Fe^3＋ ions are added.
