Cadmium was replaced by zinc in ammoniacal system using an electrically enhanced method under ultrasonic waves.Five main influencing factors were investigated by a single-factor experiment to determine the optimum par...Cadmium was replaced by zinc in ammoniacal system using an electrically enhanced method under ultrasonic waves.Five main influencing factors were investigated by a single-factor experiment to determine the optimum parameters.Cyclic voltammetry and linear sweep voltammetry were applied to investigating the reaction mechanism of electrically enhanced cementation of cadmium on a zinc plate.The optimum parameters were a temperature of 35℃,a cathode-to-anode area ratio of 1:2,an anode current density of 15 A/m2,an ultrasonic frequency of 40 kHz a reaction time of 6 h and an ultrasonic power of 100 W.The extraction rate was 99.21%,and the production of byproduct“floating sponge cadmium”was inhibited.The analysis of the cyclic voltammetry and linear sweep voltammetry diagrams showed that ultrasonic waves can promote and accelerate the replacement reaction,decrease the voltage requirement of the electrically enhanced replacement reaction,and change the reaction steps.In addition,increasing the temperature and ultrasonic power can promote and accelerate electrically enhanced replacement reactions and decrease the electric potential requirement.展开更多
Fly ash floating bead（FAFB） was modified by the nonionic surfactant polyethylene glycol（PEG） under various concentrations to improve its hydrophobility,and then PEG modified FAFB composited with polyaniline（FAFB-...Fly ash floating bead（FAFB） was modified by the nonionic surfactant polyethylene glycol（PEG） under various concentrations to improve its hydrophobility,and then PEG modified FAFB composited with polyaniline（FAFB-PEG/PAn） by emulsion polymerization method using different feed ratios of FAFBPEG.The chemical structure,phase structure,microstructure,conductivity,and dielectric properties were studied by FT-IR,XRD,SEM,four-probe technique,and LCR digital bridge,respectively.It was demonstrated that the optimal concentration of PEG was 1 mol/L and the corresponding grafting ratio was 1.42%.The phase structure of FAFB was not destroyed after modification by PEG,while the surface became smoother and could be coated by PAn successfully according to SEM technique.Compared to that of dodecylbenzenesulfonic acid doped PAn（PAn-DBSA）,the conductivity of FAFB-PEG/PAn was decreased by 10-100 times after introduction of various amounts of FAFB-PEG,especially the value could be decreased to 0.01 S cm^-1 if 50 wt%of FAFBPEG was provided.Additionally,the dielectric constant and loss factor of FAFB-PEG/PAn composites gradually decreased with increasing amount of FAFB-PEG in the frequency range of 100 KHz-2 MHz,namely,the dielectric constant could be still kept at 500 and correspondingly the loss factor decreased to 4.7 at 100 KHz if50 wt%of FAFB-PEG was provided.The leaking current phenomenon derived from PAn-DBSA could also be weakened by FAFB-PEG.展开更多
The chemical resistances of float-glasses subjected to different electric field strength and temperature were investigated. It is indicated that the chemical resistance increases after the float-glasses are annealed w...The chemical resistances of float-glasses subjected to different electric field strength and temperature were investigated. It is indicated that the chemical resistance increases after the float-glasses are annealed with suitable temperature and electric field strength. It is also observed that the Na＋ content varies obviously under the conditions of 570℃, 1500 V/cm and 10 min, implying that the application of thermal/electric field improves the chemical resistance of float-glass online.展开更多
WT8.BZ]A new quasi 2-dimensional analytical approach to predicting the ring voltage,edge peak fields and optimal spacing of the planar junction with a single floating field limiting ring structure has been proposed,ba...WT8.BZ]A new quasi 2-dimensional analytical approach to predicting the ring voltage,edge peak fields and optimal spacing of the planar junction with a single floating field limiting ring structure has been proposed,based on the cylindrical symmetric solution and the critical field concept.The effects of the spacing and reverse voltage on the ring junction voltage and edge peak field profiles have been analyzed.The optimal spacing and the maximum breakdown voltage of the structure have also been obtained.The analytical results are in excellent agreement with that obtained from the 2-D device simulator,MEDICI and the reported result,which proves the presented model valid.展开更多
电场积分方程(electric field integral equation,EFIE)“低频崩溃”现象是指当电磁波波长远大于离散单元的尺寸时,分析结果不准确的现象。它的发生与计算机浮点数的字长有关,高精度浮点数的普及有助于缓解低频崩溃现象的发生,但目前还...电场积分方程(electric field integral equation,EFIE)“低频崩溃”现象是指当电磁波波长远大于离散单元的尺寸时,分析结果不准确的现象。它的发生与计算机浮点数的字长有关,高精度浮点数的普及有助于缓解低频崩溃现象的发生,但目前还没有关于不同精度的浮点数的低频崩溃临界阈值的研究报道。本文定量研究了不同字长浮点数的EFIE不发生低频崩溃的适用范围,以便在该适用范围内,研究人员仅须简单地修改现有EFIE代码的浮点数字长就可以进行电磁特性的准确分析而不发生低频崩溃,避免现有低频问题都需要修改基函数或积分方程等分析技术,为低频电磁分析增加了一种可选择的简便解决办法。经过数值算例的验证,高精度浮点数的EFIE可以将低频崩溃现象发生的离散网格的电尺寸降低到2.5×10^(−13),这已经能够处理我们常见的低频崩溃问题。展开更多
针对金属连接板和金属螺栓固定的格构式复合材料杆塔在人工污秽试验时整塔出现局部放电的现象,对小尺寸复合材料试片进行针对性的人工污秽模拟试验,试验结果显示悬浮金属部件的存在使电场发生畸变,促进并维持污层干燥带的产生。使用静...针对金属连接板和金属螺栓固定的格构式复合材料杆塔在人工污秽试验时整塔出现局部放电的现象,对小尺寸复合材料试片进行针对性的人工污秽模拟试验,试验结果显示悬浮金属部件的存在使电场发生畸变,促进并维持污层干燥带的产生。使用静电场分析方法对复合材料杆塔塔头部分在污秽条件下进行电场仿真计算,结果玻璃绝缘子串承担的电压超过40%,最大电场强度达到462 k V/m,使得绝缘子表面污层受潮后容易发生局部放电并发展成电弧,进而塔身所有金属部件周围也发生局部放电。展开更多
基金Project (51574294) supported by the National Natural Science Foundation of ChinaProject (2018zzts447) supported by the Fundamental Research Funds for the Central Universities of Central South University, China
文摘Cadmium was replaced by zinc in ammoniacal system using an electrically enhanced method under ultrasonic waves.Five main influencing factors were investigated by a single-factor experiment to determine the optimum parameters.Cyclic voltammetry and linear sweep voltammetry were applied to investigating the reaction mechanism of electrically enhanced cementation of cadmium on a zinc plate.The optimum parameters were a temperature of 35℃,a cathode-to-anode area ratio of 1:2,an anode current density of 15 A/m2,an ultrasonic frequency of 40 kHz a reaction time of 6 h and an ultrasonic power of 100 W.The extraction rate was 99.21%,and the production of byproduct“floating sponge cadmium”was inhibited.The analysis of the cyclic voltammetry and linear sweep voltammetry diagrams showed that ultrasonic waves can promote and accelerate the replacement reaction,decrease the voltage requirement of the electrically enhanced replacement reaction,and change the reaction steps.In addition,increasing the temperature and ultrasonic power can promote and accelerate electrically enhanced replacement reactions and decrease the electric potential requirement.
基金Funded by National Natural Science Foundation of China(No.51204131)
文摘Fly ash floating bead（FAFB） was modified by the nonionic surfactant polyethylene glycol（PEG） under various concentrations to improve its hydrophobility,and then PEG modified FAFB composited with polyaniline（FAFB-PEG/PAn） by emulsion polymerization method using different feed ratios of FAFBPEG.The chemical structure,phase structure,microstructure,conductivity,and dielectric properties were studied by FT-IR,XRD,SEM,four-probe technique,and LCR digital bridge,respectively.It was demonstrated that the optimal concentration of PEG was 1 mol/L and the corresponding grafting ratio was 1.42%.The phase structure of FAFB was not destroyed after modification by PEG,while the surface became smoother and could be coated by PAn successfully according to SEM technique.Compared to that of dodecylbenzenesulfonic acid doped PAn（PAn-DBSA）,the conductivity of FAFB-PEG/PAn was decreased by 10-100 times after introduction of various amounts of FAFB-PEG,especially the value could be decreased to 0.01 S cm^-1 if 50 wt%of FAFBPEG was provided.Additionally,the dielectric constant and loss factor of FAFB-PEG/PAn composites gradually decreased with increasing amount of FAFB-PEG in the frequency range of 100 KHz-2 MHz,namely,the dielectric constant could be still kept at 500 and correspondingly the loss factor decreased to 4.7 at 100 KHz if50 wt%of FAFB-PEG was provided.The leaking current phenomenon derived from PAn-DBSA could also be weakened by FAFB-PEG.
基金Funded by the Key Technologies R & D Program of Hubei Province (2007AA101C25)
文摘The chemical resistances of float-glasses subjected to different electric field strength and temperature were investigated. It is indicated that the chemical resistance increases after the float-glasses are annealed with suitable temperature and electric field strength. It is also observed that the Na＋ content varies obviously under the conditions of 570℃, 1500 V/cm and 10 min, implying that the application of thermal/electric field improves the chemical resistance of float-glass online.
文摘WT8.BZ]A new quasi 2-dimensional analytical approach to predicting the ring voltage,edge peak fields and optimal spacing of the planar junction with a single floating field limiting ring structure has been proposed,based on the cylindrical symmetric solution and the critical field concept.The effects of the spacing and reverse voltage on the ring junction voltage and edge peak field profiles have been analyzed.The optimal spacing and the maximum breakdown voltage of the structure have also been obtained.The analytical results are in excellent agreement with that obtained from the 2-D device simulator,MEDICI and the reported result,which proves the presented model valid.
文摘电场积分方程(electric field integral equation,EFIE)“低频崩溃”现象是指当电磁波波长远大于离散单元的尺寸时,分析结果不准确的现象。它的发生与计算机浮点数的字长有关,高精度浮点数的普及有助于缓解低频崩溃现象的发生,但目前还没有关于不同精度的浮点数的低频崩溃临界阈值的研究报道。本文定量研究了不同字长浮点数的EFIE不发生低频崩溃的适用范围,以便在该适用范围内,研究人员仅须简单地修改现有EFIE代码的浮点数字长就可以进行电磁特性的准确分析而不发生低频崩溃,避免现有低频问题都需要修改基函数或积分方程等分析技术,为低频电磁分析增加了一种可选择的简便解决办法。经过数值算例的验证,高精度浮点数的EFIE可以将低频崩溃现象发生的离散网格的电尺寸降低到2.5×10^(−13),这已经能够处理我们常见的低频崩溃问题。
文摘针对金属连接板和金属螺栓固定的格构式复合材料杆塔在人工污秽试验时整塔出现局部放电的现象,对小尺寸复合材料试片进行针对性的人工污秽模拟试验,试验结果显示悬浮金属部件的存在使电场发生畸变,促进并维持污层干燥带的产生。使用静电场分析方法对复合材料杆塔塔头部分在污秽条件下进行电场仿真计算,结果玻璃绝缘子串承担的电压超过40%,最大电场强度达到462 k V/m,使得绝缘子表面污层受潮后容易发生局部放电并发展成电弧,进而塔身所有金属部件周围也发生局部放电。
