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Critical behavior of quasi-two-dimensional ferromagnet Cr_(1.04)Te_(2)

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Chinese Physics B 2024年第7期33卷 87-94页

作者：钮伟宋沁心常世琦王敏袁奎高嘉程王硕王振东刘凯斐刘萍徐永兵张晓倩普勇 Jiangsu Provincial Engineering Research Center of Low Dimensional Physics and New Energy&School of Science Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Electronic Science and Engineering Nanjing UniversityNanjing 210023China Key Laboratory of Quantum Materials and Devices of Ministry of Education School of PhysicsSoutheast UniversityNanjing 211189China

The self-intercalation of Cr into pristine two-dimensional(2D) van der Waals ferromagnetic CrTe_(2),which forms chromium tellurides(Cr_(x)Te_(2)),has garnered interest due to their remarkable magnetic characteristics and the wide variety of chemical compositions ***,comprehensive basic characterization and magnetic studies are conducted on quasi-2D ferromagnetic Cr_(1.04)Te_(2) *** of the isothermal magnetization curves are conducted around the critical temperature to systematically investigate the critical ***,the critical exponents β=0.2399,γ=0.859,and δ=4.3498,as well as the Curie temperature T_(C)=249.56 K,are determined using various methods,including the modified Arrott plots,the Kouvel-Fisher method,the Widom scaling method,and the critical isotherm *** results indicate that the tricritical mean-field model accurately represents the critical behavior of Cr_(1.04)Te_(2.A magnetic phase diagram with tricritical phenomenon is thus *** investigations confirm that the critical exponents obtained conform to the scalar equation near T_(C),indicating their self-consistency and *** work sheds light on the magnetic properties of quasi-2D Cr_(1.04)Te_(2),broadening the scope of the van der Waals crystals for developments of future spintronic devices operable at room temperature.

关键词： critical behavior van der Waals magnets self-intercalation magnetic measurement

Room Temperature Ferromagnetism in Ga1-xHoxN （x=0.0 and 0.05） Diluted Magnetic Semiconductor Thin Films

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Chinese Journal of Chemical Physics 2012年第3期25卷 313-317,373,374页

作者： Ghulam Murtaza Rai Muhammad Azhar Iqbal yong-bing xu lain Gordon Will Qasim Mahmood Department of Physics University of the Punjab Lahore 54590 Pakistan Spintronics Laboratory Department of Electronics The University of York York Y010 5DD UK

Holmium doped GaN diluted magnetic semiconductor thin films have been prepared by thermal evaporation technique and subsequent ammonia annealing. X-ray diffraction mea- surements reveal all peaks belong to the purely hexagonal wurtzite structure. Surface mor- phology and composition analysis were carried out by scanning electron microscopy and energy dispersive spectroscopy respectively. The room temperature ferromagnetic proper- ties of Gal-xHoxN （x=0.0, 0.05） films were analyzed using vibrating sample magnetometer at room temperature. Magnetic measurements showed that the undoped films （i.e. GaN） exhibited diamagnetic behavior, while the Ho-doped （Gao.95Hoo.05N） film exhibited a ferro- magnetic behavior.

关键词： Diluted magnetic semiconductor Holmium doping X-ray diffraction Scan-ning electron microscopy Room temperature ferromagnetism

Abnormal grain growth induced byδ→γphase transformation in Fe-based shape memory alloys

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Journal of Materials Science & Technology 2024年第5期172卷 196-201页

作者： Huabei Peng Liqiu yong Gaixia Wang Jiazhen Yan bing xu Yuhua Wen School of Mechanical Engineering Sichuan UniversityChengdu 610065China Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610041China

Grain boundaries,including low-angle,high-angle,and coinci-dence boundaries,are intrinsic interfaces in polycrystalline *** heat-treatment at sufficiently high temperatures,grain boundary migration occurs because the grain boundaries are ther-modynamically ***,grain growth occurs due to a decrease in grain boundary area after heat-treatment[1].In general,there are two types of grain growth:normal grain growth,where grains grow uniformly,and abnormal grain growth,where one or a few grains selectively grow and engulf surround-ing smaller grains,leading to the formation of large grains,some-times several millimeters or greater in size[2].The classical tech-nique to achieve abnormal grain growth is the strain-annealing method,which involves subjecting the material to a small strain followed by annealing[3,4].This method has been reported to ob-tain single-crystal wires or plates[1].Additionally,abnormal grain growth can be achieved by plastic straining at high temperatures,resulting in the fabrication of large grains or single crystals[5].However,the above methods are not applicable to components with complicated shapes due to the inevitable deformation ***,Omori et *** a simply method of abnor-mal grain growth to fabricate ultra-large grains,even single crys-tals,in Cu-Al-Mn[1],Fe-Mn-Al-Ni[2],and Fe-Mn-Al-Ni-Cr[6]*** method involves applying cyclic heat treatment between a high temperature BCC single-phase region and a low tempera-ture BCC+FCC two-phase region[1,2,6-12].Note that the cyclic heat treatment resulted in the formation of BCC sub-grain struc-tures responsible for abnormal grain growth[1,2,6-12].In addition,Yang et *** that abnormal grain growth occurred at above 900℃,and large-grains,even single crystals,were obtained only through annealing cast Cu-based polycrystalline alloys contained coherent nano-particles[13,14].Notably,the cyclic heat treatment and annealing cast alloys are deform

关键词： grain alloys deformation

Riverine sulfate sources and behaviors in arid environment,Northwest China:Constraints from sulfur and oxygen isotopes

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Journal of Environmental Sciences 2024年第3期137卷 716-731页

作者： Yifu xu Wenjing Liu bing xu Zhifang xu Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

The fate of riverine sulfate ion (SO_(4)^(2-)) and its environmental effects in arid environment are difficult to evaluate due to its complicated sources and strongly coupled behaviors with water cycle which is significantly modified by *** understand the sulfur cycle in aquatic systems in arid environment,the chemical and sulfur and oxygen isotopic compositions (δ^(34)S_(SO4)and δ^(18)O_(SO4)) of major rivers around the Badain Jaran Desert,northwestern China,were *** rivers had averaged SO_(4)^(2-)content at 1336μmol/L,over 10times higher than the global *** δ^(34)S_(SO4)and δ^(18)O_(SO4)values ranged from-5.3‰to+11.8‰and+1.6‰to+12.8‰,*** end-member analysis and the inverse model showed that riverine sulfate was mainly derived from evaporites dissolution (0-87%),sulfide oxidation (13%-100%) and precipitation (0-33%),indicating heterogeneity in sulfur sources and behaviors along the river drainage with the lithology variations and climate *** isotopic tools combining with hydro-chemistry compositions could be applied to reveal sulfur cycle in arid *** on the calculation,sulfide oxidation plays the primary role in the headwater and upstream in the Qilian-Mountains area,where sulfide is widely *** the proportion of evaporites dissolution contributing to riverine sulfate is much higher in downstream in a drier ***,less precipitation and higher temperature can lead to more intensive evaporation,affecting the process of sulfide oxidation and enhancing the rates of evaporites dissolution and sulfate precipitation in the basin.

关键词： Sulfur and oxygen isotopes Source apportionment Inverse model Arid environment Inland rivers Northwestern China

Timescales and contribution of heating and helicity effect in helicity-dependent all-optical switching

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Rare Metals 2023年第1期42卷 234-243页

作者： Guan-Qi Li Xiang-Yu Zheng Jun-Lin Wang Xian-Yang Lu Jing Wu Jian-Wang Cai Hao Meng Bo Liu Thomas A.Ostler yong-bing xu School of Integrated Circuits Guangdong University of TechnologyGuangzhou510006China York-Nanjing International Joint Center in Spintronics School of Electronic Science and EngineeringNanjing UniversityNanjing210093China Spintronics and Nanodevice Laboratory Department of Electronics EngineeringUniversity of YorkYorkYO105DDUK Institute of Physics Chinese Academy of SciencesBeijing100190China Key Laboratory of Spintronics Materials Devices and System of Zhejiang ProvinceHangzhou311305China College of Business Technology and EngineeringSheffield Hallam UniversitySheffieldS11WBUK

The heating and helicity effects induced by circularly polarized laser excitation are entangled in the helicity-dependent all-optical switching(HD-AOS),which hinders understanding the magnetization dynamics ***,applying a dual-pump laser excitation,first with a linearly polarized(LP) laser pulse followed by a circularly polarized(CP) laser pulse,the timescales and contribution from heating and helicity effects in HD-AOS were identified with a Pt/Co/Pt *** the LP laser pulses preheat the sample to a nearly fully demagnetized state,the CP laser pulses with a power reduced by 80% switch the sample’s *** varying the time delay between the two pump pulses,the results show that the helicity effect,which gives rise to the deterministic helicity-induced switching,arises almost instantly within 200 fs close to the pulse width upon laser *** results reveal that the transient magnetization state upon which CP laser pulses impinge is the key factor for achieving HD-AOS,and importantly,the tunability between heating and helicity effects with the unique dualpump laser excitation approach will enable HD-AOS in a wide range of magnetic material systems having wideranging implications for potential ultrafast spintronics applications.

关键词： Helicity-dependent all-optical switching Ultrafast laser Ultrafast magnetization Magneto-optical interaction

Alanine aminotransferase as a risk marker for new-onset metabolic dysfunction-associated fatty liver disease

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World Journal of Gastroenterology 2024年第25期30卷 3132-3139页

作者： Di Wang bing-Yan Zhou Lei Xiang xu-yong Chen Jie-Xiong Feng Department of Pediatric Surgery Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030Hubei ProvinceChina

In this editorial,we comment on the article by Chen et *** dysfunction-associated fatty liver disease(MAFLD)is a global public health burden whose incidence has risen concurrently with overweight and *** its detri-mental health impact,early identification of at-risk individuals is *** diagnosis is based on evidence of hepatic steatosis indicated by liver biopsy,imaging,or blood biomarkers,and one of the following conditions:Overweight/obesity,type 2 diabetes mellitus,or metabolic ***,in large-scale epidemiological studies,liver biopsies are not *** application of techniques such as ultrasonography,computed tomography,magnetic resonance imaging,and magnetic resonance spectroscopy is restricted by their limited sensitivity,low effectiveness,high costs,and need for specialized *** biomarkers offer several advantages,particularly in large-scale epidemiological studies or clinical scenarios where traditional imaging techniques are *** of cumulative effects of excess high-normal blood alanine aminotrans-ferase(ALT)levels of blood ALT levels could facilitate identification of at-risk patients who might not be detected through conventional imaging ***,investigating the utility of blood biomarkers in MAFLD should enhance early detection and monitoring,enabling timely inter-vention and management and improving patient outcomes.

关键词： Nonalcoholic fatty liver disease Metabolic dysfunction-associated fatty liver disease Alanine aminotransferase Screening Risk marker

The Essential 2-rank for Classical Groups

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Acta Mathematica Sinica,English Series 2024年第9期40卷 2169-2186页

作者： Jian Bei AN yong xu Department of Mathematics University of AucklandAucklandNew Zealand School of Mathematics and Statistics He’nan University of Science and TechnologyLuoyang 471023P.R.China

Let G be a symplectic or orthogonal group defined over a finite field with odd characteristic and let D≤G be a Sylow *** this paper,we classify the essential 2-subgroups and determine the essential 2-rank of the Frobenius category FD(G).Together with the results of An–Dietrich and Cao–An–Zeng,this completes the work of essential subgroups and essential ranks of classical groups.

关键词： Frobenius category conjugation families essential 2-rank symplectic groups orthogonal groups

High-Performance Recyclable Furan-based Epoxy Resin and Its Carbon Fiber Composites with Dense Hydrogen Bonding

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Chinese Journal of Polymer Science 2024年第1期42卷 73-86,I0008页

作者： Chang-Bo Zhao Lu-Kun Feng Hui Xie Ming-Liang Wang bing Guo Zhi-yong xue Cai-Zhen Zhu Jian xu Advanced Materials Research Institute North China Electric Power UniversityBejing 102206China Institute of Low-Dimensional Materials Genome Initiative College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China Chengdu Institute of Organic Chemistry Chinese Academy of SciencesChengdu 610041China School of Science and Shenzhen Key Laboratory of Flexible Printed Electronics Technology and Shenzhen Key Laboratory of Advanced Functional Carbon Materials Research and Comprehensive ApplicationHarbin Institute of TechnologyShenzhen 518055China

The emerging biomass-based epoxy vitrimers hold great potential to fulfill the requirements for sustainable development of *** the existence of dynamic chemical bonds in vitrimers often reduces both the thermal and mechanical properties of epoxy resins, it is challenging to produce recyclable epoxy vitrimers with both excellent mechanical properties and good thermal stability. Herein, a monomer 4-(((5-(hydroxymethyl)furan-2-yl)methylene)amino)phenol(FCN) containing furan ring with potential to form high density of hydrogen bonding among repeating units is designed and copolymerized with glycerol triglycidyl ether to yield epoxy resin(FCN-GTE), which intrinsically has dual hydrogen bond networks, dynamic imine structure and resultant high performance. Importantly, as compared to the BPA-GTE, the FCN-GTE exhibits significantly improved mechanical properties owing to the increased density of hydrogen bond network and physical crosslinking interaction. Furthermore, density functional theory(DFT) calculation and in situ FTIR analysis is conducted to decipher the formation mechanism of hydrogen bond network. In addition, the FCN-GTE possesses superior UV shielding, chemical degradation, and recyclability because of the existence of abundant imine bonds. Notably, the FCN-GTE-based carbon fiber composites could be completely recycled in an amine *** study provides a facile strategy for synthesizing recyclable biomass-based high-performance epoxy vitrimers and carbon fiber composites.

关键词： Furan Hydrogen bond network Dynamic Schiff base Carbon fiber composites Recycling

Ultrafast Magnetization Precession in Perpendicularly Magnetized L10-MnAl Thin Films with Co2 MnSi Buffer Layers

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Chinese Physics Letters 2020年第5期37卷 110-114页

作者： Si-Wei Mao Jun Lu Long Yang xue-Zhong Ruan Hai-Long Wang Da-Hai Wei yong-bing xu Jian-Hua Zhao State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083 Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100190 Beijing Academy of Quantum Information Science Beijing 100193 Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials Collaborative Innovation Center of Advanced MicrostructuresSchool of Electronic Science and EngineeringNanjing UniversityNanjing 210093

Perpendicularly magnetized L10-MnAl thin films with Co2 MnSi bufer layers were prepared on GaAs(001)substrates by molecular-beam epitaxy(MBE).The samples with high crystalline quality show a maximum uniaxial perpendicular magnetic anisotropy constant of 1.4×10^7 erg/cm^*** spin dynamics with a magnetization precession frequency up to 200 GHz was investigated by using time-resolved magneto-optical Kerr effect(TRMOKE)measurements,from which the Gilbert damping constantαof epitaxial L10-MnAl thin films is evaluated to be less than *** work provides an important reference for analyzing the current-induced magnetization switching process in MnAl-based spintronic devices.

关键词： magnetization Gilbert anisotropy