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Critical current degradation in an epoxy-impregnated rare-earth Ba_(2)Cu_(3)O_(7-x)coated conductor caused by damage during a quench
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作者 Donghui LIU Huadong YONG Youhe ZHOU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第9期1557-1572,共16页
High-temperature superconducting(HTS)rare-earth Ba_(2)Cu_(3)O_(7-x)(REBCO)coated conductors(CCs)have significant potential in high-current and high-field applications.However,owing to the weak interface strength of th... High-temperature superconducting(HTS)rare-earth Ba_(2)Cu_(3)O_(7-x)(REBCO)coated conductors(CCs)have significant potential in high-current and high-field applications.However,owing to the weak interface strength of the laminated composite REBCO CCs,the damage induced by the thermal mismatch stress under a combination of epoxy impregnation,cooling,and quenching can cause premature degradation of the critical current.In this study,a three-dimensional(3D)electromagnetic-thermal-mechanical model based on the H-formulation and cohesive zone model(CZM)is developed to study the critical current degradation characteristics in an epoxy-impregnated REBCO CC caused by the damage during a quench.The temperature variation,critical current degradation of the REBCO CC,and its degradation onset temperature calculated by the numerical model are in agreement with the experimental data taken from the literature.The delamination of the REBCO CC predicted by the numerical model is consistent with the experimental result.The numerical results also indicate that the shear stress is the main contributor to the damage propagation inside the REBCO CC.The premature degradation of the critical current during a quench is closely related to the interface shear strength inside the REBCO CC.Finally,the effects of the coefficient of thermal expansion(CTE)of the epoxy resin,thickness of the substrate,and substrate material on the critical current degradation characteristics of the epoxy-impregnated REBCO CC during a quench are also discussed.These results help us understand the relationship between the current-carrying degradation and damage in the HTS applications. 展开更多
关键词 epoxy-impregnated rare-earth Ba_(2)Cu_(3)O_(7-x)(REBCO)coated conductor(CC) QUENCH DAMAGE critical current degradation shear stress
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Progressive current degradation and breakdown behavior in GaN LEDs under high reverse bias stress 被引量:1
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作者 赵琳娜 于沛洪 +6 位作者 郭子骧 闫大为 周浩 吴锦波 崔志强 孙华锐 顾晓峰 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第8期429-432,共4页
The progressive current degradation and breakdown behaviors of GaN-based light emitting diodes under high reversebias stress are studied by combining the electrical, optical, and surface morphology characterizations. ... The progressive current degradation and breakdown behaviors of GaN-based light emitting diodes under high reversebias stress are studied by combining the electrical, optical, and surface morphology characterizations. The current features a typical “soft breakdown” behavior, which is linearly correlated to an increase of the accumulative number of electroluminescence spots. The time-to-failure for each failure site approximately obeys a Weibull distribution with slopes of about 0.67 and 4.09 at the infant and wear-out periods, respectively. After breakdown, visible craters can be observed at the device surface as a result of transient electrostatic discharge. By performing focused ion beam cuts coupled with scan electron microscope, we observed a local current shunt path in the surface layer, caused by the rapid microstructure deterioration due to significant current heating effect, consistent well with the optical beam induced resistance change observations. 展开更多
关键词 GaN LEDs current degradation breakdown behavior reverse bias stress
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Anomalous Channel Length Dependence of Hot-Carrier-Induced Saturation Drain Current Degradation in n-Type MOSFETs
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作者 张春伟 刘斯扬 +7 位作者 孙伟锋 周雷雷 张艺 苏巍 张爱军 刘玉伟 胡久利 何骁伟 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第8期193-195,共3页
The dependencies of hot-carrier-induced degradations on the effective channel length Lch,eff are investigated for n-type metal-oxide-semiconductor field effect transistor (MOSFETs). Our experiments find that, with d... The dependencies of hot-carrier-induced degradations on the effective channel length Lch,eff are investigated for n-type metal-oxide-semiconductor field effect transistor (MOSFETs). Our experiments find that, with decreasing Lch,eff, the saturation drain current (Iasat ) degradation is unexpectedly alleviated. The further study demonstrates that the anomalous Lch,eff dependence of Idsat degradation is induced by the increasing influence of the substrate current degradation on the lazar degradation with Lch,eff reducing. 展开更多
关键词 Anomalous Channel Length Dependence of Hot-Carrier-Induced Saturation Drain current degradation in n-Type MOSFETs
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Degradation of the Emission Current from the Field Emitter Caused by Ion Bombardment
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作者 姚建楠 李俊涛 《Journal of Southeast University(English Edition)》 EI CAS 2002年第4期326-330,共5页
In field emission devices, the emission current sometimes degrades with the time. The mechanism of the current degradation is complicated. In this paper, a program is used to simulate the movement of the electron beam... In field emission devices, the emission current sometimes degrades with the time. The mechanism of the current degradation is complicated. In this paper, a program is used to simulate the movement of the electron beam from a field emitter. According to the current distribution and the trajectories of the primary electron beam, it is shown that the residual gas is ionized and the ion pairs are generated. The trajectories of the positive ions are simulated. With the different locations and kinetic energy of i... 展开更多
关键词 field emitter degradation of the emission current ion bombardment
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Model of radiation-induced gain degradation of NPN bipolar junction transistor at different dose rates
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作者 赵启凤 庄奕琪 +1 位作者 包军林 胡为 《Journal of Semiconductors》 EI CAS CSCD 2015年第6期68-71,共4页
Ionizing-radiation-induced current gain degradation in NPN bipolar junction transistors is due to an increase in base current as a result of recombination at the surface of the device. A model is presented which ident... Ionizing-radiation-induced current gain degradation in NPN bipolar junction transistors is due to an increase in base current as a result of recombination at the surface of the device. A model is presented which identifies the physical mechanism responsible for current gain degradation. The increase in surface recombination velocity due to interface states results in an increase in base current. Besides, changing the surface potential along the base surface induced by the oxide-trapped charges can also lead to an increased base current. By combining the production mechanisms of oxide-trapped charges and interface states, this model can explain the fact that the current gain degradation is more severe at a low dose rate than at a high dose rate. The radiations were performed in a Co60 source up to a total dose of 70 krad(Si). The low dose rate was 0.1 rad(Si)/s and the high dose rate was 10 rad(Si)/s. The model accords well with the experimental results. 展开更多
关键词 RADIATION bipolar junction transistors current gain degradation model
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