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Skyrmion Hall effect with spatially modulated Dzyaloshinskii-Moriya interaction

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Frontiers of physics 2019年第5期14卷 71-79页

作者： Liping Zhou Ren Qin ya-qing Zheng Yong Wang School of Physics Nankai UniversityTianjin 300071China

The skyrmion Hall effect is theoretically studied in the chiral ferromagnetic film with spatially modulated Dzyaloshinskii-Moriya *** cases including linear,sinusoidal,and periodic rectangular modulations have been considered,where the increase,decrease,and the periodic modification of the size and velocity of the skyrmion have been observed in the microscopic *** phenomena are well explained by the Thiele equation,where an effective force on the skyrmion is induced by the inhomogeneous Dzyaloshinskii Moriya *** results here suggest that tlic skyrmion Hall effect can be manipulated by artificially timing the DzvaloshinskiiMoriya interaction in chiral ferromagnetic film with material engineering methods,which will be useful to design skyrmion-based spintronics devices.

关键词： magnetic skyrmion skyrmion Hall effect Thiele equation

Are the altitudinal patterns of plant diversity derived from field surveys consistent with those from empirical integrated methods?

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Journal of Mountain Science 2023年第5期20卷 1307-1315页

作者： ZHAN qing-hua FU Zhi-hao ZHOU ya-dong yaN Xue WANG qing-feng School of Life Sciences Nanchang UniversityNanchang 330031China Wuhan Botanical Garden/Core Botanical Gardens Chinese Academy of SciencesWuhan 430074China Sino-Africa Joint Research Center(SAJOREC) Chinese Academy of SciencesWuhan 430074China

Field surveys and empirical integrated methods are commonly used in the ecological research to understand the altitudinal pattern of plant diversity of ***,few studies have compared the differences between the two methods on the same ***,we addressed and compared the altitudinal patterns of species richness(SR),phylogenetic diversity(PD),the standardized effect size of phylogenetic diversity(PDses)and mean phylogenetic distance(MPDses)of about 580 angiosperms growing on Mount Kenya from two independent datasets:one is based on our several times field surveys in this mountain and another one is based on empirical data integrated from *** found that the altitudinal diversity patterns of field surveys dataset were consistent with the empirical integrated *** SR and PD showed hump-shaped patterns along the altitude,and both PDses and MPDses showed monotonically decreasing patterns along the *** ratio of diversity between field surveys dataset and empirical integrated dataset were gradually increase along the *** research provides new insight for understanding the altitudinal diversity patterns of plants of a tropical mountain.

关键词： Mount Kenya Africa Surveys Interpolation method Taxonomic Phylogenetic

MOTION OF TRACER PARTICLES IN A CENTRIFUGAL PUMP AND ITS TRACKING CHARACTERISTICS

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Journal of Hydrodynamics 2012年第5期24卷 785-793页

作者： LI ya-lin YUAN Shou-qi tang Yue YUAN Jian-ping Research Center of Fluid Machinery Engineering and Technology Jiangsu University Zhenjiang 212013 China

The Basset-Boussinesq-Oseen （BBO） equation can be used for most flows to trace the motion of a particle, but in a centrifugal pump, among the forces that act on the particles, one should also include those due to the impeller rotation, as additional effects. This paper firstly reviews various approximations of the BBO equation for the motion of dispersion particles in a viscous fluid. Then based on the motion equation for particles in low Reynolds number centrifugal pumps, a formula for calculating the tracking characteristics of tracer particles is deduced through the Fourier integral transformation. After that the deviations of the particle motion from the fluid motion, as predicted by the various approximations, are discussed and compared. At last, with an emphasis on the Particle Image Velocimetry （PIV） results, the tracking characteristics of particles are estimated. Also, advantages and disadvantages of different tracer particles are discussed and suitable tracer particles for application in PIV studies for flow fields in centrifugal pumps are suggested.

关键词： tracer particles equations of motion tracking characteristics centrifugal pump Particle Image Velocimetry (PIV)

Synthesis and Characterization of Picolinamide Calix[6]arenes Derivatives

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Chinese Chemical Letters 2006年第6期17卷 747-750页

作者： Dong qing LIU ya qing FENG Hao Hui GU Wen Liang XU School of Chemical Engineering and Technology Tianjin University Tianjin 300072

Three full-substituted calix[6]arenes containing the picolinamide groups were synmesized and characterized by IR, ^1HNMR and MS, after series reactions, including lower rim etherification, upper rim ipso-nitration, re... 详细信息

关键词： Calixarene picolinamide synthesis characterization.

Fluorescent probes for detection of biothiols based on “aromatic nucleophilic substitution-rearrangement” mechanism

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Chinese Chemical Letters 2019年第10期30卷 1791-1798页

作者： yan-Fei Kang Li-ya Niu qing-Zheng yang Hebei Key Laboratory of Quality&Safety Analysis-Testing for Agro-Products and Food and College of Laboratory MedicineHebei North UniversityZhangjiakou 075000China Key Laboratory of Radiopharmaceuticals Ministry of EducationCollege of ChemistryBeijing Normal UniversityBeijing 100875China

Biothiols,including cysteine(Cys),homocysteine(Hey),and glutathione(GSH) play important roles in physiological processes,and the detection of thiol using fluorescent probes has attracted attention due to their high sensitivity and selectively and invasive on-time ***,the similar structures and reactivity of these biothiols present great challenges for selective *** review focused on the the "aromatic nucleophilic substitution-rearrangement(SNAr-rearrangement) mechanism",which provided a powerful tool to design fluorescent probes for the discrimination between *** classify the fluorescent probes according to types of fluorophores,such as difluoroboron dipyrromethene(BODIPY),nitrobenzoxadiazole(NBD),cyanine,pyronin,naphthalimide,coumarin,and so *** hope this review will inspire exploration of new fluorescent probes for biothiols and other relevant analytes.

关键词： Biothiols Fluorescent probes Aromatic nucleophilic substitution Rearrangement Fluorophores Bioapplication

STUDY ON EXACT ANALYTICAL SOLUTIONS FOR TWO SYSTEMS OF NONLINEAR EVOLUTION EQUATIONS

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Applied Mathematics and Mechanics(English Edition) 2001年第8期22卷 925-934页

作者： yaN Zhen-ya(闫振亚) ZHANG Hong-qing(张鸿庆) Department of Applied Mathematics Dalian University of Technology Dalian 116024 P R China Department of Applied Mathematics Dalian University of Technology Dalian 116024 P R China

The homogeneous balance method was improved and applied to two systems Of nonlinear evolution equations. As a result, several families of exact analytic solutions are derived by some new ansatzs. These solutions contain Wang's and Zhang's results and other new types of analytical solutions, such as rational fraction solutions and periodic solutions. The way can also be applied to solve more nonlinear partial differential equations.

关键词： nonlinear evolution equations improved homogeneous balance method exact analytical solution solitary wave solution rational solution

Uniform Rice-like CdS Particles Prepared from Water-in-oil Microemulsions

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Chemical Research in Chinese Universities 2006年第1期22卷 11-13页

作者： ZHOU Hai-cheng XU Sheng PENG qing LI ya-dong The Key Laboratory of Atomic ＆ Molecular Nanosciences of the Ministry of Education Department of ChemistryTsinghua UniversityBeijing100084P.R.China Department of Chemistry and Engineering Shandong University of Technology Zibo 255000 P. R. China

Uniform rice-like CdS particles were synthesized in cyclohexane/Triton X-100/n-pentanol/water quaternary microemulsions. The as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy, and electron diffraction. The results indicate that the size and the shape of the rice-like CdS particles can be influenced by the molar ratio of water to the surfactant（w value） and the reactant concentrations.

关键词： W/O microemulsion Rice-like CdS nanoparticle Value of w Morphology

Carbothermic reduction behaviors of Ti–Nb-bearing Fe concentrate from Bayan Obo ore in China

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International Journal of Minerals,Metallurgy and Materials 2018年第1期25卷 28-36页

作者： Guang Wang ya-xing Du Jing-song Wang qing-guo Xue State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

To support the development of technology to utilize low-grade Ti-Nb-bearing Fe concentrate, the reduction of the concentrate by coal was systematically investigated in the present paper. A liquid phase formed when the Ti Nb-bearing Fe concentrate/coal composite pel- let was reduced at temperatures greater than 1100℃. The addition of CaCO3 improved the reduction rate when the slag basicity was less than 1.0 and inhibited the formation of the liquid phase. Mechanical milling obviously increased the metallization degree compared with that of the standard pellet when reduced under the same conditions. Evolution of the mineral phase composition and microstructure of the reduced Ti-Nb-bearing Fe concentrate/coal composite pellet at 1100~C were analyzed by X-ray diffraction and scanning electron microsco- py-energy-dispersive spectroscopy. The volume shrinkage value of the reduced Ti-Nb-bearing Fe concentrate/coal composite pellet with a basicity of 1.0 was approximately 35.2% when the pellet was reduced at 1100℃ for 20 min, which enhanced the external heat transfer to the lower layers when reduced in a practical rotary hearth furnace. The present work provides key parameters and mechanism understanding for the development of carbothermic reduction technology of a Ti-Nb-bearing Fe concentrate incorporated in a pyrometallurgical utilization flow sheet.

关键词： Ti-Nb bearing iron concentrate carbothermic reduction basicity mechanical milling volume shrinkage

Photogalvanic effect induced charge and spin photocurrent in group-V monolayer systems

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Frontiers of physics 2023年第6期18卷 253-261页

作者： Li-Wen Zhang ya-qing yang Jun Chen Lei Zhang School of Physics and Information Engineering Shanxi Normal UniversityTaiyuan 030031China State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser SpectroscopyShanxi UniversityTaiyuan 030006China State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Theoretical PhysicsShanxi UniversityTaiyuan 030006China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China

Photogalvanic effect(PGE)occurs in materials with non-centrosymmetric structures when irradiated by linearly or circularly polarized ***,using non-equilibrium Green’s function combined with density functional theory(NEGF-DFT),we investigated the linear photogalvanic effect(LPGE)in monolayers of group-V elements(As,Sb,and Bi)by first-principles ***,by designing a two-probe structure based on the group-V elements,we found a giant anisotropy photoresponse of As between the armchair and zigzag ***,we analyzed Sb and Bi’s charge and spin photocurrent characteristics when considering the spin-orbit coupling(SOC)*** is found that when the polarization direction of linearly polarized light is parallel or perpendicular to the transport direction(θ=0°or 90°),the spin up and spin down photoresponse in the armchair direction has the same magnitude and direction,leading to the generation of net charge ***,in the zigzag direction,the spin up and spin down photoresponse have the same magnitude with opposite directions,leading to the generation of pure spin ***,it is understood by analyzing the bulk spin photovoltaic(BSPV)coefficient from the symmetry point of ***,we found that the net charge current generated in the armchair direction and the pure spin current generated in the zigzag direction can be further tuned with the increase of the material’s buckling *** results highlight that these group-V monolayers are promising candidates for novel functional materials,which will provide a broad prospect for the realization of ultrathin ferroelectric devices in optoelectronics due to their spontaneous polarization characteristics and high Curie temperature.

关键词： group-V monolayers photogalvanic effect pure spin current