检索结果-南通市图书馆

Synthesis and Characterization of CoFe_2O_4 Nanoparticles

Journal of Wuhan University of Technology(Materials Science) 2005年第B12期20卷 195-197页

作者：黄福龙 Biomedical Materials and Engineering Center Wuhan University of Technology Wuhan 430070 China

CoFe2O4 nanoparticles that were synthesized by coprecipitation method were heat-treated at different temperature , and analyzed by XRD and TEM. The particle size and magnetic properties of CoFe2O4 nanoparticles also was tested. The results showed that the average sizes became large as the heat-treated temperature increased, the saturation magnetization and remanent magnetization increased with the heat-treated temperature too.

关键词： nanoparticles coprecipitation method magnetic properties hysteresis loop

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Zero—field—cooled and field—cooled magnetizations and magnetic susceptibility of itinerant ferromagnet SrRuO3

引用

Chinese Physics B 2002年第8期11卷 827-833页

作者：侯登录姜恩永等 DepartmentofAppliedPhysics TianjinUniversityTianjin300072China

Zero-field-cooled (ZFC) magnetization, field-cooled (FC) magnetization, ac magnetic susceptibility and majorhysteresis loops of itinerant ferromagnet SrRuO3 have been measured at magnetic ordering temperatures ranging from5 to 160 K. An empirical model is proposed to calculate the measured ZFC magnetization. The result indicates that thecalculated ZFC magnetization compares well with the measured one. Based on the generalized Preisach model, boththe ZFC and FC curves are reproduced by numerical simulations. The critical temperature and critical exponents aredetermined by measuring the ac magnetic susceptibility in different bias magnetic fields at temperatures in the vicinityof the point of phase transition.

关键词： zero-field-cooled magnetization field-cooled magnetization magnetic sus-ceptibility hysteresis loop

来源：

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

EFFECTS OF SLIP MODE ON CYCLIC BEHAVIOR OF PRESTRAINED MATERIALS

引用

Acta Metallurgica Sinica(English Letters) 1993年第5期6卷 326-331页

作者： CHAI Huifen RUAN Zheng FAN Quncheng (Xi’an Jiaotong University,Xi’an,China CHAI Huifen,associate professor,Department of Materials,Xi’an Jiaotong University,Xi’an 710049,China

The cyclic behaviours of two prestrained materials with different slip modes have been com- pared.From the analysis of hysterisis loops,it is suggested that the decrease in back stress dominates the cyclic process of Cu-Zn alloy with planar slip mode,while the decrease in frictional stress is the main factor affecting the behaviour of Cu with wavy slip mode.The re- lation between the dislocation configuration and internal stress has been also discussed.By means of the relation just mentioned,the variations of dislocation configuration before and after fatigue of the two materials,the differences in their softening mechanism and mechani- cal behaviour could be interpreted.

关键词： slip mode fatigue softening hysteresis loop internal stress

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Preisach analysis of （La0.2Nd0.8）0.67Pb0.33MnO3

引用

Chinese Physics B 2005年第5期14卷 1051-1054页

作者：曹先胜肖春涛 GywnWilliams RoyRoshko MaterialDepartment TheSecondNorthwestUniversityforNationalitiesNingxia750021China PhysicsDepartment LanzhouUniversityLanzhou730000China DepartmentofPhysicsandAstronomy UniversityofManitobaR3T2N2Canada

The perovskite (La0.2Nd0.8)0.67Pb0.33MnO3 (LNPMO) with a Curie temperature TC=220K is characterized by measuring the zero field cooled (ZFC) and field cooled (FC) moments over a wide range of temperature 2K＜T＜290K in an applied field of Ha=3978.87A/m, and also by the major hysteresis loop over the field range |Ha|≤1061kA/m at T=10K. The data analysed within the framework of a generalized Preisach model, which includes thermal fluctuations,critical effects, and a temperature-dependent distribution of free energy barriers. The analysis shows that the response function of LNPMO is dominated by the growth of the anisotropy barriers.

关键词： Preisach model hysteresis loop magnetization

来源：

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

Research and Design of DTC System Based on Six-phase Asymmetrical BLDCM

引用

CES Transactions on Electrical Machines and Systems 2018年第1期2卷 123-128页

作者： Chunyuan Bian Guannan Zhao Xiaoxia Li Yongkui Man Department of Information Science􀋂Engineering Northeastern UniversityShenyang 110189China

In this paper,the torque ripple problem of six-phase asymmetrical brushless DC motor(BLDCM)is studied.First,the basic structure of BLDCM is introduced,and the operation principle of six-phase asymmetrical BLDCM that is studied in the thesis is expounded.Then,the principle of direct torque control(DTC)system of BLDCM is also discussed,and the improved system is proposed,including using the torque hysteresis loop and opening current hysteresis loop,and choosing the improved voltage vector to make the PWM-ON-PWM modulation.Finally,the DTC system simulation model is built,and the system is also tested by the experiment.According to the results of experiment and simulation,the DTC system designed in this thesis can control the six-phase asymmetrical BLDCM stably and reliably,and the problem of high frequency and torque ripple is solved well.

关键词： Six-phase asymmetrical BLDCM DTC hysteresis loop torque ripple voltage space vector

来源：

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

Structure and Magnetic Property of a Dysprosium Single-Ion Magnet with Hula Hoop-like Geometry

Structure and Magnetic Property of a Dysprosium Single-Ion M...

引用

中国化学会第八届全国配位化学会议

作者： Mei Guo Jinkui Tang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences University of Chinese Academy of Science

The field of lanthanide-based single-molecule magnets(SMMs) has been flourishing over the last decades due to the strong spin-orbital coupling interactions and large anisotropy of lanthanide ions[1].One of the most striking trends to have emerged is that simple lanthanide single-ion magnets(SIMs) with only one spin carrier can easily elaborate high effective barrier SMMs[2].Here we focus on a new dysprosium(Ⅲ) complex(1) synthesized by the reaction of benzamide ligand with dysprosium(Ⅲ) salt using standard Schlenk and glovebox techniques.Single-crystal X-ray studies reveal that complex 1 crystallizes in monoclinic space group C2/c with Z= 4.The Dy site is eight-coordinate and demonstrates a hula hoop-like coordination geometry with the cyclic ring defined by the atoms O1’,O2,O3,O3’ and N2 from two THF and two ligands.The ac susceptibility data with frequency-dependent maximum of out-of-phase signals under zero dc field reveal a typical SIM behavior,which should be attributed to the strong axiality of Dy ion due to the hula hoop-like coordination geometry around it.At low temperature,the out-of-phase peaks occur at similar frequencies,suggesting a quantum tunneling of magnetizations(QTM).Interestingly,the M versus H data give rise to a butterfly shaped hysteresis loops below 3 K for complex 1.This work provides a new and simple pathway using benzamide ligand to design SMMs.

关键词： lanthanide single-molecule magnets （SMMs） single-ion magnets （SIMs） quantum tunneling of the magnetization（QTM） hysteresis loop

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

A comparative study of magnetic properties between whole cells and isolated magnetosomes of Magnetospirillum magneticum AMB-1

A comparative study of magnetic properties between whole cel...

引用

中国科学院地质与地球物理研究所第十届(2010年度)学...

作者： LI JinHua~(1,2,3),PAN YongXin~(1,3*),LIU QingSong~(3,4),QIN HuaFeng~4,DENG ChengLong~4, CHE RenChao~5 & YANG XinAn~5 1 Key Laboratory of the Earth’s Deep Interior,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China 2 Graduate University of Chinese Academy of Sciences,Beijing 100049,China 3 Franco-Chinese Biomineralization and Nano-structures Laboratory,Beijing 100029,China 4 State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China 5 Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100080,China

The magnetic properties of magnetosome magnetite are of interdisciplinary interest because magnetosomes are potential carriers of natural remanent magnetization and paleoenvironment,as well as novel nano-biomaterials in biotechnological and biomedical applications.We carried out magnetic and electron transmission microscopy analyses of fresh Magnetospirillum magneticum AMB-1 whole cells and isolated magnetosomes.Results revealed that AMB-1 synthesized single-domain magnetite magneto-somes, which are arranged in the form of linear fragmental chain.The distinct differences of magnetic properties between these two samples can be faithfully interpreted in terms of spatial arrangement of magnetosomes and magnetostatic interaction.For the whole cells,the strong intra-chain interactions and weak inter-chain interactions generate behaviors of non-interacting uniaxial single-domain particles.Itsδ-ratio is 3.0 and passes the Moskowitz test.In contrast,the isolated magnetosome sample has reduced values of coercivity andδ-ratio(1.5),due to increasing three-dimensional magnetostatic interactions and collapse of magnetosome chains.These observations provide useful insights into applications of the biogenic magnetite(magnetosomes)in magnetic nano-materials and magnetofossils in the paleomagnetic and environmental magnetism.

关键词： Magnetospirillum magneticum AMB-1 isolated magnetosomes hysteresis loop FORC Verwey transition Moskowitz test

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：