160KA铝电解槽电、热解析及仿真试验

本文提出了一个铝电解槽阴极分区电、热解析模型及其仿真程序,并通过现场实测对该程序进行了初步验证.利用此程序对160kA中间下料、预焙槽的阴极部分进行了仿真试验.找出了能改善槽膛内形并能降低能耗的改良槽衬结构方案.此种仿真试验法能有效地提高铝电解槽设计的技术水平.     

Structural, electrical, dielectric and magnetic properties of Mn-Nd substituted CoFeO3 nano sized multiferroics

A series of Mn x Co_(1-x) Fe_(1-y) Nd_yO_3(where x=0.0–1.0 y=0.0–0.1) multiferroic nanocrystals was synthesized via sol-gel auto-combustion technique. The structure was confirmed by X-ray diffraction(XRD)while morphology was investigated by scanning electron microscopy(SEM). The electrical resistivity was observed to increase from 2.14 * 10~7 to 8.77 * 10~9 Ω-cm and activation energy was found to increase from 0.64 to 0.75 e V, while the drift mobility decreased from 4.75 * 10~(-13) to 1.27 * 10~(-15)cm~2V~(-1)S~(-1) by the substitution of Mn and Nd contents. The dielectric constant, dielectric loss and dielectric loss factor decrease with frequency and Mn-Nd contents. The saturation magnetization was increased from 34 to 70 emu g~(-1) while the coercivity decreased from 705 to 262 Oe with the increase of substituents.The increase in electrical resistivity and saturation magnetization while decrease in dielectric parameters and coercivity make these nanomaterials suitable for applications in microwave devices and longitudinal magnetic recording media.     

电学中的验证型、设计型和综合型实验对比分析

实验一般分为验证型、设计型和综合型三种。本文着重对比分析在电学实验中这三种类型实验教与学的特点。     

Size-manipulat ion, compacti on and electrical properties of barium manganite nanorods synthesized via the CHM method

A composite-hydroxide mediated method was employed to synthesize barium manganite nanorods.Diameter,surface smoothness and uniformity of these nanorods were optimized by varying reaction temperature and reaction time.The rods with an average diameter of 200 nm and length of1–1.5 μm were obtained at optimum conditions of 200 1C/48 h.The dielectric study of these rods reveals that they have higher value of dielectric constant at lower frequencies which was attributed to the interfacial and rotational type polarizations.Similarly,the increase in dielectric constant with temperature was attributed to the thermal activation of such polarizations.Furthermore,the analysis of ln(J) vs.E1/2characteristics in the temperature range of 300–400 K shows that possible operative conduction mechanism was of Poole–Frenkel type.The value of βexp was found to be 4.85 times greater than the expected theoretical value of feld lowering coeffcient with an internal feld enhancement factor ofα2 23.5.This high value of βexp may be due to some localized electric felds existing inside the sample.     

浅谈高等职业院校电气控制课程实践教学

电气控制技术实用性广,实践性强,本文根据自身教学实际,谈谈高等职业院校电气控制课程实践教学。     

Bias polarity-sensitive electrical failure characteristics of ZnSe nanowire in metal–semiconductor–metal nanostructure

The effect of bias polarity on the electrical breakdown behavior of the single ZnSe nanowire(NW) in the metal–semiconductor–metal(M–S–M)nanostructure under high current density and high bias conditions has been studied in the present paper. The experimental results show that the failure of the ZnSe NW in M–S–M nanostructure was sensitive to bias polarity since the NW commonly collapsed at the negatively biased Au metal electrode due to high Joule heat produced in NW at the reversely biased Schottky barrier. Thus, the electrical breakdown behavior of the ZnSe NW was highly dominated by the cathode-controlled mode due to the high resistance of the depletion region of ZnSe NW at the reversely biased Schottky contact.     

FX2N PLC在立式车床控制系统中的应用

针对老式继电逻辑系统接线复杂，不便维护，接点寿命低的问题，采用PLC对电气系统进行改造。设计了硬件和软件系统。证明改造后的电气控制系统简化了控制电路，降低了生产维护费用。     

电负性标度

本文介绍一种新的电负性标度理论——非自旋极化密度函数理论和自施极化密度函数理论.     

纯铜接触线材料的组织和性能

采用拉拔法制备的纯铜接触线材料，通过室温拉伸、显微硬度试验和金相显微分析等手段对其微观组织及性能进行了分析。结果表明：纯铜接触线经冷拉成型后，其金相组织纵向明显被拉长，而横向金相组织呈细小均匀分布；纯铜接触线的软化温度为200℃左右；经冷加工强化的纯铜接触线的导电率和抗拉强度分别达到了97．5％IACS和374MPa。     

住宅绿色建筑电气设计分析

本文针对近年来绿色建筑的发展情况,结合实际经验对绿色建筑电气专项课题进行了分析研究,系统、全面地阐述了住宅项目绿色建筑电气设计的依据及原则,对住宅小区绿色建筑电气设计做出了详细的说明。