检索结果-南通市图书馆

Magnetic phase transition and continuous spin switching in a high-entropy orthoferrite single crystal

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2024年第2期19卷 157-167页

作者： Wanting Yang Shuang Zhu Xiong Luo Xiaoxuan Ma chenfei shi Huan Song Zhiqiang Sun Yefei Guo Yuriy Dedkov Baojuan Kang Jin-Ke Bao shixun Cao Department of Physics Shanghai UniversityShanghai 200444China Materials Genome Institute and International Center for Quantum and Molecular Structures Shanghai UniversityShanghai 200444China School of Physics Southeast UniversityNanjing 211189China Shanghai Key Laboratory of High Temperature Superconductors Shanghai UniversityShanghai 200444China

Rare-earth orthoferrite REFeO_(3)(where RE is a rare-earth ion)is gaining *** created a high-entropy orthoferrite(Tm_(0.2)Nd_(0.2)Dy_(0.2)Y_(0.2)Yb_(0.2))FeO_(3)(HEOR)by doping five RE ions in equimolar ratios and grew the single crystal by optical floating zone *** strongly tends to form a single-phase structure stabilized by high configurational *** the low-temperature region(11.6‒14.4 K),the spin reorientation transition(SRT)ofΓ_(2)(F_(x),C_(y),G_(z))‒Γ_(24)‒Γ_(4)(G_(x),A_(y),F_(z))*** weak ferromagnetic(FM)moment,which comes from the Fe sublattices distortion,rotates from the a-to *** two-step dynamic processes(Γ_(2)‒Γ_(24)‒Γ_(4))are identified by AC susceptibility *** in HEOR can be tuned in the range of 50‒60000 Oe,which is an order of magnitude larger than that of orthoferrites in the peer system,making it a candidate for high-field spin *** spin-switching(SSW)and continuous spin-switching(CSSW)effects occur under low magnetic fields due to the strong interactions between RE‒Fe *** CSSW effect is tunable between 20‒50 Oe,and hence,HEOR potentially can be applied to spin modulation ***,because of the strong anisotropy of magnetic entropy change()and refrigeration capacity(RC)based on its high configurational entropy,HEOR is expected to provide a novel approach for refrigeration by altering the orientations of the crystallographic axes(anisotropic configurational entropy).

关键词： high-entropy oxide rare-earth orthoferrite spin reorientation transition spin switching magnetocaloric effect

Negative thermal expansion of Ca2RuO4 with oxygen vacancies

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第8期29卷 393-399页

作者： Sen Xu Yangming Hu Yuan Liang chenfei shi Yuling Su Juan Guo Qilong Gao Mingju Chao Erjun Liang Key Laboratory of Materials Physics of Education of China School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450001China Department of Applied Physics Donghua UniversityShanghai 201620China School of Physics and Electronic Engineering Zhengzhou University of Light IndustryZhengzhou 450001China

Oxygen vacancies have a profound effect on the magnetic,electronic,and transport properties of transition metal oxides but little is known about their effect on thermal *** we report the effect of oxygen defects on the structure formation and thermal expansion properties of the layered perovskite Ca2RuO4(CRO).It is shown that the CRO containing excess oxygen crystallizes in a metallic L-CRO phase without structure transition from 100 K to 500 K and displays a normal thermal expansion behavior,whereas those with oxygen vacancies adopt at room temperature an insulating S-CRO phase and exhibit an enormous negative thermal expansion(NTE)from 100 K to about 360 K,from where they undergo a structure transition to a high temperature metallic L-CRO *** to the L-CRO containing excess oxygen,the S-CRO structure has increasingly large orthorhombic strain and distinctive in-plane distortion upon *** in-plane distortion of the RuO6 octahedra reaches a maximum across 260 K and then relaxes monotonically,providing a structure evidence for the appearance of an antiferromagnetic orbital ordering in the paramagnetic phase and the A_g phonon mode suppression and phase flip across the same temperature found *** the L-and S-CRO display an antiferromagnetic ordering at about 150-110 K,with ferromagnetic ordering components at lower *** NTE in S-CRO is a result of a complex interplay among the spin,orbital,and lattice.

关键词： negative thermal expansion structure oxygen vacancies metal-insulator transition octahedra distortion

Annealing-induced long-range charge density wave order in magnetic kagome FeGe:Fluctuations and disordered structure

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 112-121页

作者： chenfei shi Yi Liu Bishal Baran Maity Qi Wang Surya Rohith Kotla Sitaram Ramakrishnan Claudio Eisele Harshit Agarwal Leila Noohinejad Qian Tao Baojuan Kang Zhefeng Lou Xiaohui Yang Yanpeng Qi Xiao Lin Zhu-An Xu Arumugam Thamizhavel Guang-Han Cao Sander Van Smaalen shixun Cao Jin-Ke Bao Department of Physics Materials Genome InstituteInstitute for Quantum Science and TechnologyShanghai UniversityShanghai 200444China Key Laboratory of Quantum Precision Measurement of Zhejiang Province School of PhysicsZhejiang University of TechnologyHangzhou 310023China School of Physics Zhejiang UniversityHangzhou 310027China Department of Condensed Matter Physics and Materials Science Tata Institute of Fundamental ResearchMumbai 400005India School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China ShanghaiTech Laboratory for Topological Physics ShanghaiTech UniversityShanghai 201210China Laboratory of Crystallography University of BayreuthBayreuth 95447Germany Department of Quantum Matter AdSEHiroshima UniversityHigashi-Hiroshima 739-8530Japan P24 PETRA IIIDeutsches Elektronen-Synchrotron DESYHamburg 22607Germany Key Laboratory for Quantum Materials of Zhejiang Province School of ScienceWestlake UniversityHangzhou 310024China Department of Physics China Jiliang UniversityHangzhou 310018China Shanghai Key Laboratory of High-resolution Electron Microscopy ShanghaiTech UniversityShanghai 201210China Collaborative Innovation Centre of Advanced Microstructures Nanjing UniversityNanjing 210093China Shanghai Key Laboratory of High Temperature Superconductors Shanghai UniversityShanghai 200444China School of Physics Hangzhou Normal UniversityHangzhou 311121China

Charge density wave(CDW) in kagome materials with the geometric frustration is able to carry unconventional ***, a CDW has been observed below the antiferromagnetic order in kagome FeGe, in which magnetism and CDW are intertwined to form an emergent quantum ground state. However, the CDW is only short-ranged and the structural modulation originating from it has yet to be determined experimentally. Here we realize a long-range CDW order by post-annealing process,and resolve the structure model through single crystal X-ray diffraction. Occupational disorder of Ge resulting from short-range CDW correlations above T_(CDW) is identified from structure refinements. The partial dimerization of Ge along the c axis is unveiled to be the dominant distortion for the CDW. Occupational disorder of Ge is also proved to exist in the CDW phase due to the random selection of partially dimerized Ge sites. Our work provides useful insights for understanding the unconventional nature of the CDW in FeGe.

关键词： charge density wave kagome disordered structure fluctuations

基于自由表面合成纹影法的大尺度圆盘中边缘波空间衰减特性研究

在线全文

学校读者我要写书评

暂无评论

水动力学研究与进展（A辑） 2023年第5期38卷 737-746页

作者：李庆文张仕敏师晨斐林志良上海交通大学船舶海洋与建筑工程学院海洋工程国家重点实验室上海200240

当盛有液体的薄层圆柱形器皿(圆盘)受到外加垂向激励时,其近壁处弯月形液面的不稳定性会激发出毛细重力波,此类表面波的波形和传播特性与边壁形状有关,故被称为边缘波。该文采用改进的自由表面合成纹影法,结合多步滤波技术,对实验产生... 详细信息

当盛有液体的薄层圆柱形器皿(圆盘)受到外加垂向激励时,其近壁处弯月形液面的不稳定性会激发出毛细重力波,此类表面波的波形和传播特性与边壁形状有关,故被称为边缘波。该文采用改进的自由表面合成纹影法,结合多步滤波技术,对实验产生的边缘波进行自由表面重构,获得准确的液面高度变化实时信息,进一步定量分析大尺度圆盘中边缘波的空间传播特性。研究发现,大尺度圆盘中的边缘波是一种指数衰减的谐振波,其传播过程可分为激发与过渡、纯衰减和自相互作用三个阶段。实验结果表明黏性耗散、有限尺度效应和外加激励等因素对边缘波的空间衰减有影响,且空间衰减系数与激励频率之间是指数关系,衰减长度与激励频率的平方之间是反比关系。

关键词：边缘波毛细重力波液体自由表面重构黏性耗散空间衰减特性

同方期刊数据库

在线全文

学校读者我要写书评

暂无评论

投资者情绪与股价同步性研究

西安石油大学学报（社会科学版） 2024年第1期33卷 9-17页

作者：王小鹏史陈菲西安石油大学经济管理学院陕西西安710065

以2018-2021年沪深证券交易所A股上市公司为样本,研究投资者情绪对股价同步性的影响及作用机制。研究表明:投资者情绪与股价同步性显著正相关,支持了“信息效率”说;高涨的投资者情绪能够通过提升融资约束加剧股价同步性。进一步研究发... 详细信息

以2018-2021年沪深证券交易所A股上市公司为样本,研究投资者情绪对股价同步性的影响及作用机制。研究表明:投资者情绪与股价同步性显著正相关,支持了“信息效率”说;高涨的投资者情绪能够通过提升融资约束加剧股价同步性。进一步研究发现,投资者情绪对股价同步性的积极作用在证券监管力度较低、会计稳健性较低与股权激励较高的企业中更为明显。从优化信息获取渠道、健全公司内部信息公开披露机制、强化监管部门监督职能等方面对抑制股价同步性提出了建议。

关键词：股价同步性投资者情绪融资约束

在线全文

学校读者我要写书评

暂无评论

表面活性剂浓度对介孔光催化材料的影响

工业水处理 2018年第11期38卷 48-51页

作者：李明慧程寒飞黄建史宸菲中冶华天工程技术有限公司江苏南京210019 南京师范大学环境学院江苏南京210023

利用溶胶-凝胶技术,用表面活性剂F127和钛酸异丙酯、硝酸铈、氧氯化锆制备前驱体溶胶,老化后通过煅烧去除表面活性剂形成介孔光催化材料ZrO_2-CeO_2-TiO_2。通过N2吸附脱附、红外光谱、X射线衍射、透射电子显微镜等表征发现表面活性剂... 详细信息

利用溶胶-凝胶技术,用表面活性剂F127和钛酸异丙酯、硝酸铈、氧氯化锆制备前驱体溶胶,老化后通过煅烧去除表面活性剂形成介孔光催化材料ZrO_2-CeO_2-TiO_2。通过N2吸附脱附、红外光谱、X射线衍射、透射电子显微镜等表征发现表面活性剂浓度的变化对介孔材料的结构和性能均有影响,随浓度增加,比表面积逐渐增大,晶型由无定型变为锐钛矿型,介孔有序度增加,在反应物料F127浓度为6 mmol/L时,介孔材料的晶型、有序度最好,光催化性能最高。

关键词：表面活性剂介孔材料二氧化钛染料

在线全文

学校读者我要写书评

暂无评论

甲醇四塔精馏系统的多目标优化

石油化工自动化 2013年第6期49卷 40-42页

作者：施辰斐赵霞邵惠鹤上海交通大学电子信息与电气工程学院

粗甲醇的精馏是甲醇生产中的高耗能、低能效环节,而变负荷四塔精馏系统具有非线性、强耦合、强时延的特点,针对该系统的能耗优化既是生产成本控制和节能减排的重点也是难点。研究当进料负荷、进料质量、出料要求等条件改变时,如何调节... 详细信息

粗甲醇的精馏是甲醇生产中的高耗能、低能效环节,而变负荷四塔精馏系统具有非线性、强耦合、强时延的特点,针对该系统的能耗优化既是生产成本控制和节能减排的重点也是难点。研究当进料负荷、进料质量、出料要求等条件改变时,如何调节系统的控制参数,以达到产品单位能耗和产量多目标的协同优化。实验结果表明单目标优化的单位能耗降低很多,但牺牲了产量;多目标优化的能耗优化效果略逊于单目标,但稳定地提高了产量。

关键词：甲醇四塔精馏遗传算法多目标优化节能

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

露天煤矿松动爆破效果评价分析

露天采矿技术 2022年第1期37卷 94-97页

作者：吕文伟史晨飞张禹国家能源集团准能公司哈尔乌素露天煤矿内蒙古鄂尔多斯010300 内蒙古安邦安全科技有限公司内蒙古呼和浩特010090

为实现对露天矿松动爆破效果的评价,基于模糊数学理论,结合矿山实际选取大块率、根底率、炸药单耗3个评价指标,效果等级划分为4级,建立了松动爆破模糊综合评价模型;以哈尔乌素露天煤矿为研究对象,在1055、1025 m水平选取4个炮区进行分... 详细信息

为实现对露天矿松动爆破效果的评价,基于模糊数学理论,结合矿山实际选取大块率、根底率、炸药单耗3个评价指标,效果等级划分为4级,建立了松动爆破模糊综合评价模型;以哈尔乌素露天煤矿为研究对象,在1055、1025 m水平选取4个炮区进行分析研究。结果表明:该评价方法符合矿山及时、快速的生产需求,可为爆破参数反馈优化提供依据。

关键词：松动爆破模糊综合评价评价指标爆破效果反馈优化

在线全文

学校读者我要写书评

暂无评论

Fe掺杂对YCrO3微结构及磁特性的影响

功能材料 2020年第3期51卷 3075-3081页

作者：苏玉玲郭锦锦史晨飞龚高尚程学瑞王永强李子炯郑州轻工业大学物理与电子工程学院

利用溶胶-凝胶法制备YCr0.6Fe0.4O3样品,研究了Fe^3+掺杂对YCrO3的微结构与磁特性的影响。结果表明,样品具有良好的单相正交结构,属于Pnma空间群。拉曼及傅里叶红外光谱结果显示,Fe^3+掺杂使得Y/Cr-O键长被拉伸,增加了晶格畸变,导致振... 详细信息

利用溶胶-凝胶法制备YCr0.6Fe0.4O3样品,研究了Fe^3+掺杂对YCrO3的微结构与磁特性的影响。结果表明,样品具有良好的单相正交结构,属于Pnma空间群。拉曼及傅里叶红外光谱结果显示,Fe^3+掺杂使得Y/Cr-O键长被拉伸,增加了晶格畸变,导致振动模式向低波数偏移。热磁M-T曲线表明,体系在TN^183K发生反铁磁相变,随温度降低磁化强度增加,FC曲线在128K出现较宽的驼峰,温度降至85K,磁化强度达到最小(0.08 A·m^2/kg),随后逐渐增加。这主要是Fe^3+掺杂使YCrO3样品内Cr^3+O^2-Cr^3+、Fe^3+O^2-Fe^3+反铁磁有序与Cr^3+O^2-Fe^3+铁磁相互作用共存,Fe/Cr团簇导致磁化反转现象。当T<80K时,M-H曲线出现磁台阶效应,T=50K时出现交换偏置现象,场冷磁场增加,磁滞回线基本重合,表明样品内反铁磁和铁磁界面处产生钉扎效应。

关键词：拉曼光谱傅里叶变换红外光谱磁化台阶磁化反转钉扎效应