水泥污秽对复合绝缘子闪络特性的影响

青海电力科学试验研究院的李志玮等人以水泥和氯化钠为污秽,研究了氯化钠污秽（盐密）一定的情况下,水泥污秽（灰密）对复合绝缘子污秽闪络特性的影响。结果发现,灰密对绝缘子人工污秽闪络电压有影响,闪络电压与灰密成幂函数关系,且灰密与闪络电压的影响是独立的。     

输电用玻纤/聚氨酯复合材料电气性能研究

使用改性聚氨酯树脂,调整工艺及配方生产复合材料试样,测试其电气绝缘性能。通过对试样的体积电阻率、表面电阻率、介质损耗、耐电痕化、水扩散试验及接触角进行测试,结果证明改性树脂的电气绝缘性能良好,可以用作复合材料输电杆塔。     

模拟火电烟囱工况下乙烯基酯树脂基FRP的腐蚀性研究

本文利用含1 500 ppm H2SO4、250 ppm H2SO3以及250 ppm HCl的混合溶液在65℃加热浸泡试样,再在180℃、200℃高温烘烤试样的实验方法来模拟火电玻璃钢烟囱在运行过程中的腐蚀情况,研究用于火电玻璃钢烟囱设备生产的2种乙烯基酯树脂901和907与相应的纤维增强材料组合的复合材料的耐受性能。结果表明:试样的空泡和分层随实验周期的延长而加剧,空泡和分层的程度与选用的树脂及纤维增强材料的种类相关;酚醛环氧乙烯基酯树脂907比溴化双酚A型环氧乙烯基酯树脂901有更好的耐蚀耐温性能;碳纤维与玻璃纤维复合使用比单纯使用玻璃纤维(C型)的试样具有更好的耐分层和空泡的性能。     

一体化成型耐磨复合材料的磨损性能研究

将耐磨涂层与树脂基复合材料采用RTM工艺一体化成型,并对一体化成型复合材料的耐磨性能进行了测试分析,采用三维白光干涉表面形貌仪测试了磨损试样的表面形貌,采用激光粒度分析仪对所使用的硬质粉体进行了粒度分析,采用电子显微镜观测了耐磨复合材料的内部结构。结果表明,复合材料试样的摩擦系数与磨痕深度情况相一致,即试样的摩擦系数越小,其磨痕深度也越小。一体化成型耐磨复合材料表面涂层的连续相为树脂基体,限制了该种复合材料在高速摩擦条件下的使用。     

蜂窝夹层结构芯子塌陷修补工艺研究

在树脂基蜂窝夹层复合材料零部件的加工与使用过程中,其夹层结构常会发生芯子破损或塌陷。为降低制造与使用成本,延长零部件的使用寿命,需要对夹层结构的缺陷部位进行修补。本文针对夹层结构的芯子塌陷进行了修补,并对芯子的剪切及夹层结构的平面拉伸性能、长梁弯曲性能进行了测试。结果表明:采用挖补/完全灌封的修补方式,可使修补后试样的性能满足使用要求。与无缺陷试样相比,修补后试样的长梁弯曲强度及平面拉伸强度分别提高了42%和88%。该方法为树脂基夹层复合材料的修补提供了安全、有效的解决方案。     

SCRIMP用原位分相增韧中温环氧树脂体系制备及复合材料性能

针对复合材料真空辅助树脂浸渍模塑技术(SCRIMP)对树脂体系要求进行配方设计及性能测试。采用动态差示扫描量热(DSC)法,运用Kissinger动力学方程研究了基础树脂的固化反应动力学。通过添加QS-VA-3型原位分相型增韧剂,改善了基础树脂脆性,依据力学性能测试结果确定最佳添加量。对增韧环氧树脂体系进行等温/非等温黏度特性研究,确定了SCRIM P灌注成型过程的适用期,并使用该技术成型了增韧环氧树脂体系/单向玻璃纤维布复合材料试样,发现与玻璃纤维复合后具有强度高、界面性能好及低电压绝缘性能良好特点,但牺牲了高电压环境下绝缘性能。     

网带炉烧结工艺对PTFE基三层复合材料摩擦学性能的影响

通过湿法压轧复合工艺制备了聚四氟乙烯(PTFE)基三层复合材料,采用网带炉对复合材料试样进行了烧结,对试样分别进行了油循环和干摩擦两种端面摩擦磨损试验,研究了网带炉不同烧结温度和烧结频率对PTFE基三层复合材料摩擦学性能的影响,对试样承载能力、摩擦系数、磨痕深度及磨痕形貌进行了表征。结果表明,随着烧结温度和烧结频率在一定范围内增加,试样的承载能力、减摩性和耐磨性都先增加后减小,试样露铜及剥落程度则先减小后增大。当烧结温度为365℃,烧结频率为25 Hz时,PTFE基三层复合材料的综合摩擦学性能最佳。     

聚脲弹性体/纤维增强树脂基复合材料抗冲击性能研究

玻璃纤维增强树脂基复合材料在使用过程中极易受到外力冲击,造成复合材料结构破坏,严重威胁其安全使用寿命。研究了聚脲弹性体涂层对玻璃纤维增强乙烯基树脂复合材料抗冲击性能的影响。通过简支梁摆锤冲击试验和光学显微镜对前涂覆(FCGF)、后涂覆(BCGF)及未涂覆(NCGF)试样进行对比测试。研究结果表明,聚脲弹性体涂层的弹性形变和断裂破坏能够大幅增加冲击能耗,提高整体的冲击强度。当试样聚脲涂层厚度相同时,前涂覆(FCGF)试样聚脲弹性体冲击后并未完全断裂,主要依靠弹性形变吸收冲击能量,起缓冲减震作用;后涂覆(BCGF)试样聚脲弹性体发生断裂破坏能够消耗更多的冲击能量,其整体结构破坏最小,冲击强度更高。     

温度对酚醛树脂/丁腈橡胶复合材料摩擦学性能的影响

采用机械共混法将酚醛树脂（PF）与丁腈橡胶（NBR）进行混合而制得PF/NBR复合材料,研究了PF用量对NBR的拉伸性能、撕裂性能及硬度的影响,使用多功能材料表面性能综合测试仪、三维表面形貌仪和扫描电子显微镜对力学性能最优的PF/NBR复合材料试样A 2（添加5份PF）在不同温度下的摩擦性能进行了探究,并与未添加PF的试样A 0进行了对比,此外还对PF/NBR复合材料的磨损机理进行了初步分析。结果表明,当温度超过75 ℃时,试样A 0的摩擦系数曲线整体呈持续上升的趋势,同时其表面有较多孔洞,分子间结合力下降,耐磨性变差,而试样A 2的摩擦系数则基本保持稳定,磨损行为表明其磨损机理由磨粒磨损逐渐转变为黏着磨损;相对于试样A 0而言,试样A 2在高温下仍能保持较好的摩擦性能。     

MgO-ZrO_2复合材料的烧结和热震稳定性

以烧结镁砂和单斜氧化锆粉为原料,进行了Mg O-Zr O2复合材料的制备。通过XRD和SEM-EDS分析及显气孔率、体积密度、常温抗折强度、线膨胀系数和1100℃~室温水冷热震稳定性的测试,探讨了Zr O2的用量对Mg O-Zr O2复合材料的烧结和热震稳定性的影响。结果表明:随着Zr O2用量的增加,复合材料试样的致密度和常温抗折强度呈现出先增大后减小的趋势,复合材料试样的热膨胀系数逐步减小,复合材料试样的热震稳定性呈现出先变好后变差的趋势;当Zr O2用量为30%时,Mg O-Zr O2复合材料试样的烧结性能和热震稳定性最好。     

施主半导化BaTiO3PTC陶瓷耐压性能研究

通过工艺实验,性能测试和微观结构分析,研究了施主掺杂半导化BaTiO_3陶瓷的耐压性能。结果表明,该陶瓷耐压性能不仅与PTC效应,压阻效应有关,还与显微组织结构中存在的玻璃相有关。调整Al_2O_3、SiO_2烧结添加剂比例,在显微组织结构中形成莫来石微晶体的试片,具有良好的耐压性能。依据热平衡原理,建立了PTC陶瓷耐压方程,该方程表征了耐压性能与各影响因素之间的相互关系。本文用该方程对一些实验现象进行了讨论。     

Numerical analysis of characteristics of microactuators driven by liquid crystals

For the purpose of developing liquid crystalline microactuators, the transient behaviors of a nematic liquid crystal between two parallel plates have been computed for various parameters such as applied voltage, the gap between the plates, and the twist and tilt angles at the plates. The Leslie-Ericksen theory has been selected as a constitutive equation. The twist angle has an effect on the induced velocity profiles; for example, the induced flow is planar at the twist angle of 0°, while the flow has an out-of-plane component when the twist angle is not 0°. Transient behaviors of shear stress acting on the plates, the flowrate, and the maximum values of the velocity, and the tilt angle between the plates have been reported. In addition, we have investigated the effects of the applied voltage, the gap between the plates, and the tilt angle at the plates on the above-mentioned values. We can develop microactuators with arbitrary characteristics by suitably controlling the applied voltage, the size of the actuators, and the director anchoring conditions.     

常压等离子体表面亲水化改性聚丙烯薄膜

采用常压等离子体表面处理聚丙烯薄膜,通过接触角考察氩气、氧气及处理时间、放电电压对聚丙烯表面亲水性的影响.同时比较不同条件下处理的聚丙烯薄膜接触角憎水性恢复现象.研究发现:聚丙烯薄膜表面经常压等离子体处理后,接触角显著下降,氧气较氩气条件下更低;随放电电压增高,处理时间延长,接触角呈下降趋势,最终稳定于一极小值;在氧气氛围中处理时间的延长有利于减轻接触角恢复程度,从而可获得较高的、稳定的亲水性聚丙烯薄膜.结果表明:常压等离子体是聚合物表面亲水化改性的简单有效的处理技术.     

基于混沌理论的触点交流接触压降的检测技术

针对混沌振子的微弱信号理论在触点的交流接触压降应用开展深入的研究。分别对噪声、电压频率和电压初始相角对检测误差进行了分析并提出相应的对策。阐述了采用Duffing振子的交流接触压降的检测方法,并进行了仿真验证。     

Optimal drift region for diamond power devices

In power devices such as Schottky Barrier Diodes or Field Effect Transistors, the breakdown voltage is linked to the design of the drift layer but also to the physical properties of the material used. Diamond, with its high critical electric field due to its large band gap, opens the way to power components able to withstand very high voltage with outstanding figures of merit. Nevertheless, a particular attention has to be paid to the design of the drift layer to take benefit of these outstanding properties. Indeed, the drift region thickness, doping level and consequently the punch through or non-punch through designs must be well designed to reach the desired breakdown value and to minimize the ON state resistance at the same time. Here, a focus on the optimization of the specific ON state resistance as function of the breakdown voltage figure of merit has been carried out, while optimizing the drift layer and calculating the specific ON state resistance of unipolar high voltage diamond power devices. Based on the ionization integral calculation with impact ionization coefficients adapted to diamond, we performed an accurate analysis to find the best punch through design of the drift layer offering the lowest ON state resistance at a given breakdown voltage value. This theoretical study has been first applied in a one dimensional approach of the breakdown voltage. An additional 2D cylindrical coordinate analysis was performed to quantify the radius effect on the breakdown voltage value, and to compare the 2D breakdown voltage with the 1D breakdown voltage, for different drift region designs. These results offer preliminary design rules to fabricate more efficient unipolar diamond power devices. At the material level, this analysis also points out that thicknesses and doping levels required to achieve such structures are quite challenging for crystal growth in the context of high voltage power devices.     

基于SVPWM的三电平整流器的仿真研究

将ABC坐标系中的三相正弦电压合成一旋转空间电压矢量,采用空间电压矢量法,对整流器交流侧电压进行控制。二相坐标变换后,可以确定电源电压矢量的相位角,从而可以实现对整流器功率因数的控制。最后,基于MATLAB的SIMULINK仿真环境,建立了SVPWM仿真模型和三电平整流器的仿真模型,给出了控制系统结构,对三电平PWM整流器的系统进行仿真。成功仿真出部分波形,但由于控制结构不够完美,波形还有待改进。     

铝合金表面耐久性超疏水防护膜的制备与表征

通过酸刻蚀-沸水浴处理构筑微纳米分级结构,进而通过喷涂含有磷酸铝胶黏剂（AP）和低表面能物质——全氟辛基三氯硅烷（PFOTS）的悬浮液增强结合力并降低表面能,从而在国产7B04铝合金表面制备了耐久性超疏水防护膜。利用场发射扫描电子显微镜（FESEM）、X射线光电子能谱仪（XPS）、傅里叶变换红外光谱仪（FTIR）、接触角测试仪（CA）、电化学阻抗谱（EIS）等技术以及多种环境模拟实验对样品进行了表征,结果显示,制备的防护膜表面水静态接触角（WCA）高达158.4°,滑动角（SA）为0°,呈现出超疏水和低黏附性;膜层电阻（R_c）约为101.55 kΩ·cm²,在NaCl腐蚀介质中的电荷转移电阻（R_t）增大了近2个数量级,表现出优异的防护性能;样品可以经受多种破坏,具有理想的机械耐久性、化学耐久性和环境耐久性。     

Synthesis of titanium nitride for self-aligned gate AlGaN/GaN heterostructure field-effect transistors

In this study, titanium nitride (TiN) is synthesized using reactive sputtering for a self-aligned gate process. The Schottky barrier height of the TiN on n-GaN is around 0.5 to 0.6 eV and remains virtually constant with varying nitrogen ratios. As compared with the conventional Ni electrode, the TiN electrode presents a lower turn-on voltage, while its reverse leakage current is comparable with that of Ni. The results of annealing evaluation at different temperatures and duration times show that the TiN/W/Au gate stack can withstand the ohmic annealing process at 800°C for 1 or 3 min. Finally, the self-aligned TiN-gated AlGaN/GaN heterostructure field-effect transistors are obtained with good pinch-off characteristics.     

Preparation and characterization of durable superhydrophobic protective coatings on aluminum alloy

The durable superhydrophobic protective coatings on the 7B04 aluminum alloy surface was prepared by using acid etching and boiling water bath to construct micro-nano hierarchical structure, and then spraying suspension containing aluminum phosphate adhesive (AP) and perfluorooctyltrichlorosilane (PFOTS) to increase adhesion and reduce surface energy. The samples were characterized by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), contact angle measurement (CA), electrochemical impedance spectroscopy(EIS) and a variety of the environmental simulation experiments. The results showed that the static water contact angle (WCA) of the surface is 158.4° and the slide angle (SA) is about 0°, suggesting superhydrophobicity and low adhesion to water. The coating resistance (R_c) was as high as 101.55 kΩ· cm² and the charge transfer resistance (R_t) in NaCl corrosion medium increased by nearly two orders of magnitude, showing excellent protective performance. The sample can withstand a variety of damages, with ideal mechanical durability, chemical durability and environmental durability.     

Formation of honeycomb polysulfone film with controlled wettability by surfactant-assisted electric breath figure

A surfactant-assisted electric breath figure method, SAEBF, was applied to form the polysulfone, PSF, film. Experimentally, the sodium dodecyl-benzenesulfonate, SDDBS, was employed and the voltage was varied. FESEM images showed that the SAEBF formed PSF films have the honeycomb structure and the pore diameter was reduced with the applied voltage increase. Water contact angle on the honeycomb PSF film surfaces was found to increase with the applied voltage increase and there has a critical voltage at about 0.6 kV among those applied voltages because the applied voltage at lower or higher caused the film surface in hydrophilic or hydrophobic, respectively. A related mechanism was discussed.