Electrically conducting suspensions formed by polyaniline

Polyaniline was synthesized with the chemical oxidation in the presence of poly(vinylpyrrolidone) as a surfactant for small-sizing polyaniline grains. It was dispersed in glycerin including sulfuric acid to yield electrically conducting solution. Voltammograms of the solution by the two-electrode measurement showed the proportionality of the Ohm's law in the cell voltage from −0.2 to 0.2 V. Voltammograms by the three-electrode measurement in the domain 0.0-1.5 V versus Ag|AgCl were different from the Ohmic law and Faradaic current of polyaniline, because of a mixture of both the contributions. The conductance did not vary with the volume fraction of polyaniline up to 20% and enhanced drastically until 35% with large fluctuation, and then increased proportionally with the volume fraction. This variation was explained in terms of the electric percolation with a threshold at the volume fraction of 20-35%. The mixture with over 45% fraction was actually solid. The suspension was applied to confirming the relation between the Ohmic current at a microelectrode and its diameter. The current showed a linear relation with the electrode diameter with a small intercept of the diameter, of which value corresponded to the size of polyaniline grains.     

Influence of electric field and current on the strength of depoled GaN piezoelectric semiconductive ceramics

By using three-point bending tests, the effects of an applied DC electric field and current on the strength of depoled GaN piezoelectric semiconductive ceramics are investigated. Under combined mechanical-voltage-electrical current loading, the corresponding stress and electric fields and carrier distribution in specimens are analyzed based on the finite element method. It is shown that, when an electric field of 0.95 kV cm^–1 is applied, the bending strength decreases by 14.7% and then, remains unchangeable with further increase of the electric field. In contrast, the bending strength decreases from 11.5 to 8.5 MPa as the applied electric current increases from 0 to 5 × 10⁴ A m^–2. The results imply that there is a strong correlation between the bending strength and electric field or current for piezoelectric semiconductive ceramics.     

家用电器用绝缘搪瓷釉研究

家用电器用绝缘搪瓷釉研究蒋伟忠（轻工业部玻璃搪瓷工业科学研究所２０００５２）ＡｎＩｎｖｅｓｔｉｇａｔｉｏｎｏｎＩｎｓｕｌａｔｉｏｎＥｎａｍｅｌｆｏｒＥｌｅｃｔｒｉｃＡｐｐｌｉａｎｃｅ￥ＪｉａｎｇＷｅｉｚｈｏｎｇ（ＴｈｅＧｌａｓｓａｎｄＥｎａｍｅｌＲｅ...     

高聚物电性能研究的新领域

本文简述了高聚物电性能研究的几个新的热门课题：包括静电、驻极体与铁电、导电与超导、非线性光学等。     

用电功率判断和调整抽油机的平衡

用电流峰值判断和调整抽油机的平衡一直在广泛应用,其特点是方法简单方便,但存有误判现象,用电功率判断抽油机的平衡较电流法更准确可靠,后者较前者调整结果单井可平均节电12.5%。中原油田如果采用电功率法调整平衡,单井年平均节电约1万度,全局年节约电费1000多万元。     

A low cost,low energy,environmentally friendly process for producing high-purity boron carbide

Boron carbide with purity levels higher than that achievable by traditional manufacturing processes using an electric arc furnace (EAF) was produced by a novel low cost, low energy, environmentally friendly process of carbothermic reduction of boric acid (H₃BO₃) with carbon using a self-designed temperature-controllable electric resistance furnace (ERF). The process is divided into three stages: the pelleting stage, the low-temperature pre-dehydration stage, and the high-temperature reduction stage. The optimal conditions are determined as a pelleting pressure of 20?MPa, pre-dehydration temperature of 400?°C, H₃BO₃/C ratio of 3.38, and reduction temperature of 1900–2300?°C. The formation of boron carbide changes from liquid-solid reactions to gas-solid reactions with increasing temperature. Furthermore, the decreasing CO partial pressure is verified to be beneficial for the synthesis of boron carbide. The proposed process circumvents the disadvantages caused by the evaporation of large quantities of water steam and unstable reduction temperature and B/C ratios exhibited by the traditional EAF process. Moreover, it provides a more stable and controllable reduction temperature for producing high-purity boron carbide that leads to improved energy consumption, product quality, and cost efficiency and reduces air pollution mainly caused by volatilization and condensation of boron oxides.     

生产电热地毯的大型热压机

介绍了大连冰山橡塑股份有限公司于 2 0 0 0年初新开发并试制成功的电热地毯热压机,工作原理、结构及主要技术参数与特点等     

Ultrafast low-temperature near-seamless joining of Cf/SiC using a sacrificial Pr3Si2C2 filler via electric current field-assisted sintering technique

A novel layered structure material, Pr₃Si₂C₂, was synthesized at a low temperature of 850 °C using a molten salt approach for the first time, and subsequently used as the joining filler for carbon fibers reinforced SiC composites (C_f/SiC). A robust near-seamless C_f/SiC joint was successfully obtained at 1509 °C (T_i) for 30 s, while an ultrafast heating rate of 6000 °C/min was applied via electric field-assisted sintering technology. The near-seamless joining process was attributed to the newly precipitated SiC grains, which were densified well with the C_f/SiC matrix by liquid-assisted sintering. The liquid phase was in-situ formed by the eutectic reaction between Pr₃Si₂C₂ and SiC. The shear strength of the near-seamless joint obtained at 1509 °C for 30 s was 17.6 ± 3.0 MPa. The failure occurred in the C_f/SiC matrix. The formation of near-seamless C_f/SiC joints dismisses the issues related to thermal mismatch between C_f/SiC matrices and traditional joining fillers.     

硅钼棒电炉用电流反馈式程序控温系统的研制

叙述了电流反馈控制技术原理及其在硅钼棒电炉用程序控温系统中的应用 ,并提供了详细的系统电气原理图。通过热工和电量计算 ,确定了该温度控制系统主参数取值     

LDPE交联电缆料PE—K—18D022的开发研究

本文介绍了ＬＤＰＥ交联电缆料ＰＥ－Ｋ－１８Ｄ０２２的开发研制过程，包括：工艺参数的确定，过程控制，最终产品的性能等。生产实践和用户使用表明ＰＥ－Ｋ－１８Ｄ０２２的工艺过程，操作条件合理；生产参数确定准确；产品性能优良，经交联加工后生产的电缆料达到英国ＢＰ公司同类产品水平。     

Microstructural evolution of electrically activated polypropylene/layered silicate nanocomposites investigated by in situ synchrotron wide-angle X-ray scattering and dielectric relaxation analysis

Electric field was found to facilitate the destruction of layer stacking and separation of silicate layers in polypropylene (PP)/layered silicate nanocomposites, resulting in the penetration of polymer chains into silicate galleries. In this study, we describe the real-time microstructural evolution of PP/clay nanocomposites under electric field investigated by in situ synchrotron wide-angle X-ray scattering (WAXS) analysis. We were able to identify two distinctive mechanisms for the formation of nanocomposites depending on the type of electric field. We observed that the exfoliation process prevails in the AC field, while the alignment of silicates parallel to the electric field predominates in the DC field. Dielectric relaxation analysis showed that the different mechanisms originate from different charge distributions of bound ions attached to the clay surfaces due to the applied electric field.     

Formation of mono-dispersed droplets with electric periodic dripping regime in electrohydrodynamic (EHD) atomization

The formation of controllable size and dripping frequency in electrohydrodynamic (EHD) atomization with electric periodic dripping regime are of much interest and importance because of significant and wide applications, such as micro-encapsulation and ink-printing. In the present study, the experimental and theoretical works were carried out to explore droplet formation in periodic dripping regime in presence of an electric field. The dimensionless electric charge carried by each droplet produced is smaller than the 50% of critical value of the Rayleigh limit, where charge-to-mass ratio of droplets was obtained through the deflection distance in the presence of an electric field. The droplet in electric periodic dripping regime usually undergoes oscillating deformation, and finally forms a spherical droplet below the tip no more than ten times out diameter of tube. The droplet size tens of microns to one hundreds of microns decreases with an increase in applied potential. In the electric dripping mode, droplets size is independent of flow rate and affected by flow rate due to adsorption of surface active species in micro-dripping. The simplified model to predict droplets size was derived from the balance of electric, surface tension and gravity forces. The droplets size calculated in good agreement with the experiments. Meanwhile, the dripping frequency of droplets with rang of a few to several hundred hertz obtained from timeresolved images is highly dependent of liquid flow rate and electric potential. The largest dripping frequency was predicted and in reasonable agreement with the experimental results. In electric periodic dripping regime drop-on-demand droplets in size and dripping frequency further our understanding on the formation of identical droplets and are beneficial to many practical applications.     

Intensive electric arc interaction with polymer surfaces: reorganization of surface morphology and microstructure

Intense electrical arcs were applied to thermoplastic (polyamide 66) and thermoset (fiber reinforced laminated polyester) materials and the resulting carbonization/metallization process was studied on a sub-micron scale with atomic force microscopy to understand very initial stage of reorganization of surface morphology. These changes can be critical in dramatic changes in surface resistivity preceding electric breakthrough. The surface microroughness and the localization of micro- and nanoparticles at the center (arc initiation area) and along the edges of the samples were significantly different for different arc regimes. We suggested that for thermoset, the material is pulled out of the surface in the arc formation area (the center of sample). Afterwards, the intensive re-deposition occurred along the edges enhancing non-uniform ablation around the arc initiation area. In contrary, for thermoplastic samples, the entire polymer surface was re-melted that resulted in dramatic smoothing of the initially non-uniform surface morphology.     

探讨汽车变速箱电软轴手动换挡控制系统优化设计方法

在汽车行驶的过程中,特别是启动环节,换挡变速的流程对汽车行驶的安全稳定性至关重要。鉴于此种情形,本文提出了一种汽车变速箱电软轴手动换挡控制系统优化设计方法,能有效地保证汽车在行驶过程中变速箱换挡输出信号正确和快速响应,希望给汽车行驶带来不一样的体验。     

Low temperature seamless joining of SiC using a Ytterbium film

Monolithic SiC, for the first time, was seamless joined at a low temperature of 1200 °C using electric field-assisted sintering technology. A 300 nm Yb coating on SiC was used as the joining filler to form Yb₃Si₂C₂ via an in-situ reaction with the SiC. A liquid phase was formed by an eutectic reaction between Yb₃Si₂C₂ and SiC. Almost completely seamless joints were formed by the precipitated SiC grains, which were fully consolidated with the SiC matrix with the help of in-situ formed liquid phase, followed by its elimination under the uniaxial pressure. The bending strength of the seamless joint joined at 1500 °C for 15 min was as high as 257.2 ± 31.1 MPa, which was comparable to the strength of the SiC matrix. As a result, the failure occurred in the matrix indicated a sound joint was obtained. The proposed low temperature seamless joining could potentially be used for joining of SiC-based composite.     

电分流分离技术

本文建立了一套电分流分离装置，研究了在各腔室中的ｐＨ和电场分布，分离了牛血清蛋白和牛血红蛋白。处理量达２０ｍｇ／ｈ。初步结果表明此项技术具有分离速度快、成本低的特点。对生化产品的分离和提纯具有良好的应用前景。     

DC electric field effects on Ehrenfest-like relations at the glass transition

There have been numerous studies on the effects of dc and alternating electric fields on phase transitions in small-molecule mixtures and high-molecular weight polymers. Furthermore, textbook examples discuss modifications in the melting temperature of pure materials that are subjected to uniform dc fields. This thermodynamic analysis extends some of these predictions to second-order phase transitions. Upon invoking both volume and entropy continuity via the integral approach to phase equilibrium at second-order transitions, electric field effects on the glass transition are developed that parallel the Ehrenfest equations for the pressure dependence of T_g. Both T_g-field equations predict small changes in the glass transition temperature that scale as the square of the electric field strength. If one equates the dependence of T_g on the magnitude of the electric field via (i) volume continuity and (ii) entropy continuity, it is possible to obtain the electric-field analog of the Prigogine-Defay equality, in which thermophysical properties and discontinuous observables at the zero-field and field-dependent second-order phase transition temperatures are related. When the temperature and pressure dependencies of the relative electric permittivity (i.e., dielectric constant) are neglected in the absence of external fields, one recovers the classic Prigogine-Defay equality (i.e., the lower limit of the Prigogine-Defay ratio) that was developed from a consideration of volume and entropy continuity for the pressure dependence of T_g, by invoking the differential approach to phase equilibrium.     

Effect of nanoparticle surface functionality on microdomain orientation in block copolymer thin films under electric field

The electric field induced microdomain orientations has been an interesting research topic. In this article, the effect of nanoparticle surface functionality on microdomain alignments in block copolymer/nanoparticle hybrid thin films was investigated with transmission electron microscopy experiments. The presence of gold nanoparticles influenced the microdomain orientation behaviors of block copolymer/nanoparticle thin films. The possibility for complete alignment normal to the substrate was illustrated by controlling electric field strength, concentration, and surface ligands of nanoparticles. This work provides basic and essential data to understand the properties and behaviors of emerging block copolymer/nanoparticle hybrid thin films.     

电加热供料道的设计与应用

近年来,随着瓶罐玻璃行业的发展,供料道做为玻璃行业生产的关键设备之一,愈来愈受到各玻璃厂家的重视。无论从产品的成品率、产品产量、产品轻量化,还是多机组、多滴料等各方面的要求,都对供料道这一环节、对玻璃液温度的稳定性和均匀性等工艺指标提出了更高层次的要求。     

三台硅化钼高温电炉微机群控系统

用一台微机对三台硅化钼高温电炉的控温系统进行了技术改造。针对这种电炉的特点和工艺要求，介绍了硬件组成和软件设计中所考虑的技术问题。改造后，升温时温度误差最大为４℃；保温时温度误差一般为０～１℃。满足了工艺要求，两年来运行一直正常。