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Effects of direct current electric field on corrosion behaviour of copper, Cl- ion migration behaviour and dendrites growth under thin electrolyte layer 被引量:11
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作者 黄华良 潘志权 +1 位作者 郭兴蓬 邱于兵 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第1期285-291,共7页
Effect of direct current electric field (DCEF) on corrosion behaviour of copper printed circuit board (PCB-Cu), Cl-ion migration behaviour, dendrites growth under thin electrolyte layer was investigated using pote... Effect of direct current electric field (DCEF) on corrosion behaviour of copper printed circuit board (PCB-Cu), Cl-ion migration behaviour, dendrites growth under thin electrolyte layer was investigated using potentiodynamic polarization and scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS). Results indicate that DCEF decreases the corrosion of PCB-Cu;Cl-ions directionally migrate from the negative pole to the positive pole, and enrich on the surface of the positive pole, which causes serious localized corrosion; dendrites grow on the surface of the negative pole, and the rate and scale of dendrite growth become faster and greater with the increase of external voltage and exposure time, respectively. 展开更多
关键词 COPPER DENDRITES MIGRATION direct current electric field thin electrolyte layer copper printed circuit board
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Influence of Electric Field Direction on Enhanced Transdermal Delivery of Caffeine by Electroporation
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作者 胡巧红 许东航 《Journal of Chinese Pharmaceutical Sciences》 CAS 2006年第2期76-82,共7页
Aim To study the influence of electric field direction on the in vitro enhanced transdermal delivery of caffeine by eleetroporation. Methods Using side-by-side compartment diffusion cells method and Ag-Ag/AgCl electro... Aim To study the influence of electric field direction on the in vitro enhanced transdermal delivery of caffeine by eleetroporation. Methods Using side-by-side compartment diffusion cells method and Ag-Ag/AgCl electrodes, the transport of caffeine through human cadaver skin by electroporation (exponentially decaying pulse, pulse voltage = 350 V, pulse frequency = 4 pulses· min^-1, capacity = 22 μF, pulse length = 7 ms, 25 pulses) with different electric field directions was carried out and compared with passive diffusion and iontophoresis (0.25 mA·cm^ - 2, lasted for 4 h). Results (i) The cumulative quantity and flux of caffeine through human skin were increased significantly by eleetroporation or iontophoresis. (ii) The transport of caffeine by positive iontophoresis ( with electric field from donor to receptor compartment) was significantly greater than that by negative iontophoresis (with electric field from receptor to donor compartment). (iii) The transport of caffeine by positive eleetroporation (with electric field from donor to receptor compartment) was similar to that by negative eleetroporation (with electric field from receptor to donor compartment). (iv) The enhancing effect of positive iontophoresis on the transdermal delivery of caffeine was significantly greater than that of electroporation (positive or negative). Conclusion Electric field direction significantly influences the enhancing effect of iontophoresis on the transdermal delivery of caffeine, but does not influence the enhancing effect of eleetroporation. 展开更多
关键词 eleetroporation electric field direction transdermal delivery CAFFEINE
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Single Bubble Behavior in Direct Current Electric Field 被引量:10
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作者 彭耀 陈凤 +1 位作者 宋耀祖 陈民 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第2期178-183,共6页
The investigation on bubble behavior in electric field helps to analyze the mechanism of electric enhancement of boiling heat transfer. Experiments were performed to investigate the bubble deformation in direct curre... The investigation on bubble behavior in electric field helps to analyze the mechanism of electric enhancement of boiling heat transfer. Experiments were performed to investigate the bubble deformation in direct current (DC) electric field with bubbles attached to the orifice. The air bubbles were slowly generated in the transformer oil pool at different orifices, so that the effect of flow on bubble shape was eliminated. The results showed that the bubbles were elongated and the departure volume decreased when the electric field was intensified. The major and minor axes, aspect ratio and departure volume increased with increasing the orifice diameter. Both the electric field and orifice size have great influence on bubble behavior. The bubble deformation was also simulated to compare with the experimental results. The numerical and experimental data qualitatively agree with each other. 展开更多
关键词 electrohydrodynamic enhancement multiphase flow bubble behavior direct current electric field
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Positive direction of polarization-induced electric field improves formic acid electrooxidation on Pd
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作者 Shuozhen Hu Yunyun Cheng +6 位作者 Guoming Luo Kai Huang Cheng Shi Jie Xu Cheng Lian Shigang Sun Xinsheng Zhang 《Nano Research》 SCIE EI CSCD 2023年第8期10848-10856,共9页
Adjusting the adsorption energy of adsorbates on catalyst can directly regulate the catalytic performance and reaction pathways of heterogeneous catalysis.Herein,we report a novel strategy,introducing polarization-ind... Adjusting the adsorption energy of adsorbates on catalyst can directly regulate the catalytic performance and reaction pathways of heterogeneous catalysis.Herein,we report a novel strategy,introducing polarization-induced electric field(PIEF)with different directions,to manipulate the adsorption energy of intermediates and reaction pathway of formic acid electrooxidation on Pd.Tourmaline nanoparticles are applied as the PIEF provider,of which the direction is successfully controlled via aligning the dipoles in tourmaline in a strong external electric field.Experimental and theoretical results systematically reveal that positive PIEF leads to an electron-deficient state of Pd,reduced adsorption energy of COad,enhanced adsorption energy of*HCOOH and*OH,and promoted formate pathway of formic acid electrooxidation.Pd/TNP+/FTO,with the aid of positive PIEF,shows three-fold enhancement in the formic acid electrooxidation(4.74 mA·cm^(−2))with high durability and anti-poisoning ability compared with pristine Pd.This study leads a new route to design formic acid electrocatalysts and provides an understanding on how to control the adsorption energy of adsorbates on electrocatalysts by an internal electric field. 展开更多
关键词 dipole-aligned tourmaline ferroelectric material polarization-induced electric field direction PALLADIUM adsorption energy formic acid oxidation mechanism
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Universal converse flexoelectricity in dielectric materials via varying electric field direction 被引量:1
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作者 Saurav Sharma Rajeev Kumar Rahul Vaish 《International Journal of Smart and Nano Materials》 SCIE EI 2021年第1期107-128,共22页
Flexoelectricity is a symmetry independent electromechanical cou-pling phenomenon that outperforms piezoelectricity at micro and nanoscales due to its size-dependent behavior arising from gradi-ent terms in its consti... Flexoelectricity is a symmetry independent electromechanical cou-pling phenomenon that outperforms piezoelectricity at micro and nanoscales due to its size-dependent behavior arising from gradi-ent terms in its constitutive relations.However,due to this gradient term flexoelectricity,to exhibit itself,requires specially designed geometry or material composition of the dielectric material.First of its kind,the present study put forward a novel strategy of achieving electric field gradient and thereby converse flexoelectri-city,independent of geometry and material composition of the material.The spatial variation of the electric field is established inside the dielectric material,Ba_(0.67)Sr_(0.33)TiO_(3)(BST),by manipulating electrical boundary conditions.Three unique patterns of electrode placement are suggested to achieve this spatial variation.This varying direction of electric field gives rise to electric field gradient,the prerequisite of converse flexoelectricity.A multi-physics cou-pling based theoretical framework is established to solve the flexo-electric actuation by employing isogeometric analysis(IGA).Electromechanically coupled equations of flexoelectricity are solved to obtain the electric field distribution and the resulting displace-ments thereby.The maximum displacements of 0.2 nm and 2.36 nm are obtained with patterns I and II,respectively,while pattern III can yield up to 85 nm of maximum displacement. 展开更多
关键词 Converse flexoelectricity electrical boundary conditions electric field direction isogeometric analysis
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Effect of electroosmotic flow on brine imbibition in porous media
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作者 Rui WANG Xiang-an YUE +1 位作者 Xu WEI Wei ZHANG 《Water Science and Engineering》 EI CAS 2009年第1期103-111,共9页
Based on Darcy's Law and the Helmholta-Smoluchowski equation, an imbibition velocity formula for the water phase with an electric field was deduced, showing that the imbibition velocity with an electric field is to v... Based on Darcy's Law and the Helmholta-Smoluchowski equation, an imbibition velocity formula for the water phase with an electric field was deduced, showing that the imbibition velocity with an electric field is to various extents not only related to the rock permeability and characteristic length, the fluid viscosity, the oil-water interface tension and the gravity of the imbibing brine, but also to the fluid dielectric permittivity, zeta potential, applied electric field direction, and strength. Imbibition experiments with electric fields that are different in direction and strength were conducted, showing that application of a positive electric field enhances the imbibition velocity and increases the imbibition recovery ratio, while application of a negative electric field reduces the imbibition velocity and decreases the imbibition recovery ratio. The imbibition recovery ratio with a positive electric field increases with the strength of the electric field, and the imbibition recovery ratio with a negative electric field is lower than that without an electric field. 展开更多
关键词 IMBIBITION imbibition velocity electroosmotic flow electric field direction electric field strength
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Construction of multi-homojunction TiO_(2)nanotubes for boosting photocatalytic hydrogen evolution by steering photogenerated charge transfer 被引量:1
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作者 Jinbo Xue Shan Jiang +5 位作者 Chengkun Lei Huan Chang Jiaqi Gao Xuguang Liu Qi Li Qianqian Shen 《Nano Research》 SCIE EI CSCD 2023年第2期2259-2270,共12页
As an effective means to improve charge carrier separation efficiency and directional transport,the gradient doping of foreign elements to build multi-homojunction structures inside catalysts has received wide attenti... As an effective means to improve charge carrier separation efficiency and directional transport,the gradient doping of foreign elements to build multi-homojunction structures inside catalysts has received wide attentions.Herein,we reported a simple and robust method to construct multi-homojunctions in black TiO_(2) nanotubes by the gradient doping of Ni species through the diffusion of deposited Ni element on the top of black TiO2 nanotubes driven by a high temperature annealing process.The gradient Ni distribution created parts of different Fermi energy levels and energy band structures within the same black TiO_(2) nanotube,which subsequently formed two series of multi-homojunctions within it.This special multi-homojunction structure largely enhanced the charge carrier separation and transportation,while the low concentration of defect states near the surface layer further inhibited carrier recombination and facilitated the surface reaction.Thus,the B-TNT-2Ni sample with the optimized Ni doping concentration exhibited an enhanced hydrogen evolution rate of~1.84 mmol·g^(−1)·h^(−1)under visible light irradiation without the assistance of noble-metal cocatalysts,~four times higher than that of the pristine black TiO_(2)nanotube array.With the capability to create multi-homojunction structures,this approach could be readily applied to various dopant systems and catalyst materials for a broad range of technical applications. 展开更多
关键词 Ni gradient-doped TiO_(2) multi-homogeneous junction energy band bending directional built-in electric field photocatalytic H_(2)evolution
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