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Microstructure and magnetostrictive performance of NbC-doped <100>oriented Fe-Ga alloys

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International Journal of Minerals,Metallurgy and Materials 2015年第1期22卷 52-58页

作者： Chao Yuan Ji-heng Li Wen-lan Zhang Xiao-qian Bao Xue-xu Gao State Key Laboratory of Advanced Metals and Materials University of Science and Technology Beijing

The〈100〉oriented Fe83Ga17 alloy rods with various NbC contents less than 1at%were prepared by the directional solidification method at a growth rate of 720 mm·h^-1. Low NbC-content was found to affect the oriented grain growth and slightly improve the〈100〉ori-entation. Flat grain boundaries in the alloys with low NbC contents less than 0.2at%became greatly curved at higher NbC contents, and a large amount of Nb-rich precipitates were observed in the alloys with high NbC contents. Small amounts of NbC, less than 0.2at%, resulted in an increase in magnetostrictive strain due to the improvement of the〈100〉orientation, and a high magnetostrictive strain value of 335 ×10^-6 under a pre-stress of 15 MPa was obtained in the 0.1at%NbC-doped alloys. The magnetostrictive performance obviously decreased with the NbC addition higher than 0.5at%, and the strain sensitivity under no pre-stress was lower than that in the binary Fe？Ga alloy.

关键词： iron gallium alloys magnetostriction texture niobium carbide directional solidification

Texture-based magnetostriction calculation of oriented polycrystalline cobalt ferrites

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Rare Metals 2018年第5期37卷 421-426页

作者： Ji-Quan Wang Ji-heng Li Chao Yuan Xiao-qian Bao Xue-Xu Gao State Key Laboratory of Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083China

Oriented polycrystalline cobalt ferrites with different alignments were prepared via a ceramic method. The maximum magnetostriction λs up to -270×10^-6 was achieved for oriented samples, when the oriented magnetic field was above 1.0 T. Textures of all samples were determined by electron back-scattered diffraction （EBSD） technique and were used to calculate magnetostriction values of oriented polycrystalline cobalt ferrite samples. Results show that a preferred 〈001〉 orientation has been obtained within oriented sample. Calculation was done by considering the magnetostriction value as the sum of the content in volume fraction-weighted single-crystal behavior along [100], [110], [210], [310], [311], [211] and [111] directions. The calculated magnetostriction values when compared with experimentally obtained values show identical behavior as a function of applied magnetization orientation field. Good consistency of change rules between calculated values and measured ones illustrates the successful application of this method in predicting magnetostriction values of polycrystalline materials.

关键词： Magnetostriction calculation Oriented polycrystalline Cobalt ferrites Texture

Inhibition force of precipitates for promoting abnormal grain growth in magnetostrictive Fe83Ga17-(B,NbC) alloy sheets

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Rare Metals 2017年第11期36卷 886-893页

作者： Ji-heng Li Wen-Lan Zhang Chao Yuan Xiao-qian Bao Xue-Xu Gao State Key Laboratory of Advanced Metals and Materials University of Science and Technology Beijing 100083 China

Inhibition force of precipitate particles for pro- moting abnormal grain growth in magnetostrictive Feg3Ga17-（B,NbC） alloy sheets was investigated in this study. After a continuous heating and a high-temperature annealing, the Fe83Gat7 ＋ 0.5 at% B alloy sheets do not occur significant abnormal grain growth. Correspondingly, textures of { 111 }〈112〉 and { 100}〈00l〉 in addition to the Goss texture are obtained in the final annealed alloy sheets. By contrast, after the same annealing processes, the size of {110} textured grains is very large in the final annealed Fe83Gaj7 ＋ 0.5 at% NbC alloy sheets due to the abnormal grain growth, which results in a sharp Goss texture. BN precipitates were introduced into Fes3Ga17 ＋ 0.2 at% B alloy sheets by nitriding annealing at 800℃ for 2 min under NH3 atmosphere. The abnormal grain growth of Goss grains is achieved in 0.2 at% B-doped Fe83Ga17 alloy sheets after a high-temperature annealing, which is attributed to the enhanced inhibition force by introducing BN precipitates. During the recrystallization annealing process, Fe2B precipitates is easy to coarsen and decom- pose at high temperature due to the low thermal stability, resulting in a decrease or even disappearance of the inhi- bition force. For NbC and BN precipitates, the thermal stability and hardness of particles are both better than those of Fe2B precipitates, leading to strong inhibition force. Because of the preferred Goss texture, the magnetostriction of 2.05 × 10-4 and 1.81 × 10 4 is obtained in the sec- ondary recrystallized Fe83Gal7 ＋ 0.5 at% NbC and Fes3Gaw ＋ 0.2 at% B alloy sheets, respectively.

关键词： Fe-Ga alloy Magnetostriction Grain growth Inhibition force Precipitates

Regulation of electronic structure of monolayer MoS_(2) by pressure

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Rare Metals 2022年第5期41卷 1761-1770页

作者： Qiao-Lu Lin Zheng-Fang qian Xiang-Yu Dai Yi-Ling Sun Ren-heng Wang Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China

Understanding pressure-regulated electronic properties is crucial for integrating two-dimensional semiconductors into flexible electronic devices and pressure sensors. We thoroughly explored the tunability of the electronic structure of monolayer MoS_(2) upon the application of perpendicular pressure and shear stress by using first-principles calculations. The band gap increased at low pressures and then decreased as the pressure *** in the band gap are caused by the combined interaction of the increasing and decreasing trends in the band gap. The increase in the band gap is induced by the enhancement of the p–d orbital interaction at the top of the valence band(TVB). The delocalization of charge and unstable hybridization bonding causes a reduction in the band gap. The band gap under perpendicular pressure modes is closely related to the structural variation. Shear stress can effectively reduce the band gap with minimal change to the crystal structure. The maximum point at the TVB and the minimum point at the bottom of the conduction band are different for all pressure modes, resulting in various anisotropic properties. This study provides a theoretical basis for modulating the electrical and optical properties of monolayer MoS_(2).

关键词： Band gap Pressure Monolayer MoS_(2) Electronic structure Shear stress

Effect of peroxisome proliferator-activated receptor gamma agonist on heart of rabbits with acute myocardial ischemia/reperfusion injury

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Asian Pacific Journal of Tropical Medicine 2014年第4期7卷 271-275页

作者： qian Hu Jiong Chen Chao Jiang heng-Fang Liu Emergency Department Fifth.Affiliated Hospital of Zhengzhou University

Objective:To explore protective effect of rosiglitazone on myocardial ischemia reperfusion ***:A total of 48 male SD rats were randomly divided into control group(A),I/R group(B),high dose of rosiglitazone(C),low dose of rosiglitazone(D).Plasm concentration of creatine kinase(CK),CK-MB,hsCRP,Superoxide dismutase(SOD),malondialdehyde(MDA),glutathione peroxidase(GSH-Px),nitric oxide(NO)and endothelin(ET)were measured 1 h later after I/R.24 h after I/R hearts were harvested to observe pathological and ultrastructural *** and western blotting was used to test CD40 expression in myocardial *** of myocardial infarction were tested,arrhythmia rate during I/R was ***:Plasm concentration of creatine kinase(CK),CK-MB,hsCRP,NO,MDA and ET were decreased in group C,D compared with group *** concentration of T-SOD and GSHPx was increased significantly in group C,D compared with group *** with group B,pathological and ultrastructural changes in group C,D were *** infarction area and arrhythmia rate were lower in group C,D compare with group ***:Rosiglitazone can protect myocardium from I/R injury by enhancing T-SOD and GSH-Px concentration,inhibit inflammatory reaction,improve endothelial function,reduce oxidative stress and calcium overload.

关键词： Rosiglitazone Ischemia reperfusion injury Rabbit

Two-Photon Resonant Third Harmonic Generation in Carbon Monoxide

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Chinese Physics Letters 1997年第5期14卷 360-363页

作者： WANG Peng-qian CAO Chuan-shun SUN Tao-heng Department of Physics Peking UniversityBeijing 100871

Tunable coherent extreme ultraviolet radiation has been generated in CO by two-photon resonant third harmonic generation via the A^(1) II(v'=4)←X^(1)Σ+(v"=0)*** third nharmonic spectrum exhibits resolved and improved rotational lines due to the expansion cooling of the molecular *** saturation and the phase-matching of the nonlinear process are also discussed.

关键词： transition harmonic resonant

Production of biomass-derived monomers through catalytic conversion of furfural and hydroxymethylfurfural

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Green Chemical Engineering 2021年第2期2卷 158-173页

作者： hirong Yang Jing Zhang Gang qian Xuezhi duan Xinggui Zhou State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai200237China

The synthesis of biomass-derived monomers has received great attention in recent years,motivated by the depletion of fossil fuels and environmental ***,the intrinsic functionality within the biomass or biomass-derived chemicals has great potential to produce new types of monomers containing multiple acid or alcohol groups,thereby leading to materials with novel *** their versatile functional groups and easy production from cellulose/hemicellulose,furfural and hydroxymethylfurfural were regarded as very important biomass-derived platform chemicals through which multiple monomers can be produced via heterogeneous *** the current review,recent development in heterogeneous catalysis for the production of 6 bio-based monomers,furfuryl alcohol,2,5-bis(hydroxymethyl)furan,2,5-bis-(hydroxymethyl)tetrahydrofuran,1,5-pentanediol,1,6-hexanediol,and 2,5-furandicarboxylic acid,from furfural and hydroxymethylfurfural is reviewed and *** major challenge is how to efficiently and selectively convert specific functional group(s)in furfural and hydroxymethylfurfural during the production of these ***,catalyst stability issues need to be addressed due to necessity of using hot water as reaction medium and high tendency of carbonaceous deposit formation on catalyst *** current review mainly focuses on efforts of catalytic site design and modification,including selection of metal/support,use of synergy between metal and support,tuning metal size,use of inverse catalysts,adding catalytic promoters,constructing bimetallic sites,etc.,to realize efficient,selective and stable production of bio-based monomers from furfural and hydroxymethylfurfural.

关键词： Biomass-derived monomers Catalyst design Furfural Hydroxymethylfurfural Heterogeneous catalysis

Overview on Submodule Topologies,Modeling,Modulation,Control Schemes,Fault Diagnosis,and Tolerant Control Strategies of Modular Multilevel Converters

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Chinese Journal of Electrical Engineering 2020年第1期6卷 1-21页

作者： Fujin Deng Yongqing Lu Chengkai Liu qian heng qiang Yu Jifeng Zhao School of Electrical Engineering Southeast UniversityNanjing 210096China

In the present scenario,modular multilevel converters(MMCs)are considered to be one of the most promising and effective topologies in the family of high-power converters because of their modular design and good scalability;MMCs are extensively used in high-voltage and high-power *** on their unique advantages,MMCs have attracted increasing attention from academic circles over the past *** studies have focused on different aspects of MMCs,including submodule topologies,modeling schemes,modulation strategies,control schemes for voltage balancing and circulating currents,fault diagnoses,and fault-tolerant control *** summarize the current research status of MMCs,all the aforementioned research issues with representative research approaches,results and characteristics are systematically *** the final section,the current research status of MMCs and their future trends are emphasized.

关键词： Capacitor voltage balancing control circulating current control fault diagnosis fault tolerant control modular multilevel converters modulating strategy modeling scheme submodule topology

Optical Third Harmonic Generation in Methane

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Chinese Physics Letters 1997年第10期14卷 740-743页

作者： WANG Peng-qian XIE Xiao-bo SUN Tao-heng Department of Physics Peking UniversityBeijing 100871

Methane has been used as a nonlinear optical medium to produce tunable coherent vacuum ultraviolet and extreme ultraviolet radiation.A vibrational structure with a vibrational frequency of 820cm^(-1) was observed in a highly resolved third harmonic *** proved that third harmonic generation is an effective method to probe the higher excited states of molecular gases.

关键词： tunable ultraviolet harmonic