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Effect of excitation current intensity on mechanical properties of ZL205A castings solidified under a traveling magnetic field 被引量:3
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作者 Xue-yi Fan Liang Wang +6 位作者 Zhi-qiang Du Yan-qing Su Jian-bing Zhang Liang-shun Luo Zu-chuan Liu Da-ming Xu Jing-jie Guo 《China Foundry》 SCIE CAS 2015年第3期196-201,共6页
The effect of excitation current intensity on the mechanical properties of ZL205 A castings solidified under a traveling magnetic field was studied. The results of the experiment indicate that the excitation current i... The effect of excitation current intensity on the mechanical properties of ZL205 A castings solidified under a traveling magnetic field was studied. The results of the experiment indicate that the excitation current intensity of the traveling magnetic field has a great influence on the mechanical properties of the ZL205 A castings. When the excitation current intensity is 15 A, the tensile strength and elongation of ZL205 A alloy castings increase 27.2% and 67.7%, respectively, compared with those of the same alloy solidified under gravity. The improvement of mechanical properties is attributed to the decrease of micro-porosity in the alloy. Under the traveling magnetic field, the feeding pressure in the alloy melt before solidification can be enhanced due to the electromagnetic force. Moreover, the melt flow induced by the traveling magnetic field can decrease the temperature gradient. The feeding resistance will be increased because the temperature gradient decrease. So traveling magnetic field has an optimum effect on feeding. 展开更多
关键词 TMF ZL205A alloy excitation current intensity mechanical properties optimum effect
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REGULARITY OF VIBRATION RESPONSE OF MECHANICAL SYSTEM UNDER AFFECT OF VARI-FREQUENCY EXCITING FORCE
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作者 Yang Fulun Yu Junyi Hong LiJinlin University of Technology Changchun University 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 1995年第2期155-159,共5页
The vibration response formulas of the mechanical system under the affect of thevari-frequency exciting force are deduced. It is proved by the theoretical analysis and experimentalresults that the vibration response a... The vibration response formulas of the mechanical system under the affect of thevari-frequency exciting force are deduced. It is proved by the theoretical analysis and experimentalresults that the vibration response amplitude of the mechanical system under the affect of thevari-frequency exciting force is far smaller than that under the affect of the constant frequency exciting force on condition that the exciting force amplitudes are just the same;while the vari-fre-quency rate a increases to 5 Hz per second the vibration amplitude will decrease to 10% only as lowas that under the affect of the constant frequency exciting force. All these conclusions will be of significance for revealing the mechanism of suppressing chatter in van-speed cutting and analyzing theexperimental results of sine-wave scanning exciting test. 展开更多
关键词 Constant frequency exciting force Vari-frequency exciting force Vibrationresponse of mechanical system
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Bias-Polarity Dependent Electroluminescence from a Single Platinum Phthalocyanine Molecule 被引量:1
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作者 Aftab Farrukh Xiao-jun Tian +7 位作者 Fan-fang Kong Yun-jie Yu Shi-hao Jing Gong Chen Yao Zhang Yuan Liao Yang Zhang Zhen-chao Dong 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2021年第1期87-94,I0012,共9页
By using scanning tunneling microscope induced luminescence(STML)technique,we investigate systematically the bias-polarity dependent electroluminescence behavior of a single platinum phthalocyanine(PtPc)molecule and t... By using scanning tunneling microscope induced luminescence(STML)technique,we investigate systematically the bias-polarity dependent electroluminescence behavior of a single platinum phthalocyanine(PtPc)molecule and the electron excitation mechanisms behind.The molecule is found to emit light at both bias polarities but with different emission energies.At negative excitation bias,only the fluorescence at 637 nm is observed,which originates from the LUMOtHOMO transition of the neutral PtPc molecule and exhibits stepwise-like increase in emission intensities over three different excitation-voltage regions.Strong fluorescence in region(I)is excited by the carrier injection mechanism with holes injected into the HOMO state first;moderate fluorescence in region(II)is excited by the inelastic electron scattering mechanism;and weak fluorescence in region(III)is associated with an up-conversion process and excited by a combined carrier injection and inelastic electron scattering mechanism involving a spintriplet relay state.At positive excitation bias,more-than-one emission peaks are observed and the excitation and emission mechanisms become complicated.The sharp moleculespecific emission peak at〜911 nm is attributed to the anionic emission of PtPc-originated from the LUMO+1 tLUMO transition,whose excitation is dominated by a carrier injection mechanism with electrons first injected into the LUMO+1 or higher-lying empty orbitals. 展开更多
关键词 Scanning tunneling microscope induced luminescence ELECTROLUMINESCENCE excitation mechanism Platinum phthalocyanine Anionic emission Neutral emission
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Dependence of charge trapping of fluorescent and phosphorescent dopants in organic light-emitting diodes on the dye species and current density
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作者 魏斌 廖英杰 +4 位作者 刘纪忠 路林 曹进 王军 张建华 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第3期450-455,共6页
This paper utilizes multilayer organic light-emitting diodes with a thin layer of dye molecules to study the mech- anism of charge trapping under different electric regimes. It demonstrates that the carrier trapping w... This paper utilizes multilayer organic light-emitting diodes with a thin layer of dye molecules to study the mech- anism of charge trapping under different electric regimes. It demonstrates that the carrier trapping was independent of the current density in devices using fluorescent material as the emitting molecule while this process was exactly opposite when phosphorescent material was used. The triplet-triplet annihilation and dissociation of excitons into free charge carriers was considered to contribute to the decrease in phosphorescent emission under high electric fields. Moreover, the fluorescent dye molecule with a lower energy gap and ionized potential than the host emitter was observed to facilitate the carrier trapping mechanism, and it would produce photon emission. 展开更多
关键词 organic light-emitting diodes excitation mechanism charge trapping current density
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Mechanism of Excited State Double Proton Transfer in 2-Amino-3-Methoxypyridine and Acetic Acid Complex
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作者 Qing-Chi Meng Guang-Hua Ren, +1 位作者 Song-Qiu Yang Tian-Shu Chu 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第9期87-89,共3页
The excited-state double-proton transfer (ESDPT) mechanism of 2-amino-3-methoxypyridine and acetic acid com- plex is studied by the density functional theory (DFT) and time-dependent DFT with CAM-B3LYP functional.... The excited-state double-proton transfer (ESDPT) mechanism of 2-amino-3-methoxypyridine and acetic acid com- plex is studied by the density functional theory (DFT) and time-dependent DFT with CAM-B3LYP functional. The complex is connected through two different types of inter-molecular hydrogen bonds. After photo-excitation, both hydrogen bonds get strengthened, which can facilitate the ESDPT reaction. The scanned potential energy curve along the proton transfer coordinate indicates that the ESDPT reaction proceeds in a stepwise pattern. 展开更多
关键词 LYP CAM PT MOP Mechanism of Excited State Double Proton Transfer in 2-Amino-3-Methoxypyridine and Acetic Acid Complex
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Active vibration control of piezoelectric bonded smart structures using PID algorithm 被引量:9
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作者 Zhang Shunqi Rdiger Schmidt Qin Xiansheng 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2015年第1期305-313,共9页
Thin-walled structures are sensitive to vibrate under even very small disturbances. In order to design a suitable controller for vibration suppression of thin-walled smart structures, an electro-mechanically coupled f... Thin-walled structures are sensitive to vibrate under even very small disturbances. In order to design a suitable controller for vibration suppression of thin-walled smart structures, an electro-mechanically coupled finite element(FE) model of smart structures is developed based on first-order shear deformation(FOSD) hypothesis. Considering the vibrations generated by various disturbances, which include free and forced vibrations, a PID control is implemented to damp both the free and forced vibrations. Additionally, an LQR optimal control is applied for comparison.The implemented control strategies are validated by a piezoelectric layered smart plate under various excitations. 展开更多
关键词 piezoelectric walled smart layered bonded mechanically suppression validated zigzag excitation
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