检索结果-南通市图书馆

Magnetic Properties of Nanocrystalline Powder Cores Fabricated by Mechanically Crushed Powders

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2015年第1期22卷 67-71页

作者： Chun-bo HUANG tian-cheng liu Xiang-yue WANG Cao-wei LU De-ren LI Zhi-chao LU China Iron and Steel Research Institute Group Advanced Technology and Materials Co. Ltd.

Fe73. 5 Cu1 Nb3 Si15.5B7 nanocrystalline powder cores with different particle sizes ranging from 10 to 125 9m were fabricated by cold-pressing techniques. The cores exhibited increased core loss P cv and decreased initial permea- bility μi with addition of fine powders below 50 μm in size, and the content should be less than 40 mass%. It was thought to be closely related to the high coercive force H c due to the stresses generated during the crushing process and high demagnetization fields of small powders. Furthermore, modifying the alloy compositions by adding defined amount of Ni could improve the soft magnetic properties, including superior characteristics of permeability under high direct current （DC） bias field and comparable low core loss at high frequency.

关键词： nanocrystalline powder core mechanical crush particle size DC bias

Magnetic Properties of FeSiBC Amorphous Alloy Powder Cores Using Mechanical-crushed Powder

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2014年第11期21卷 1055-1058页

作者： Chun-bo HUANG tian-cheng liu Xiang-yue WANG Cao-wei LU De-ren LI Zhi-chao LU China Iron and Steel Research Institute Group R&D Center of Advanced Technology and Materials Co. Ltd.

The FeSiBC amorphous powder cores were fabricated using powders of the FeSiBC amorphous ribbons which were mechanically crushed for a short time, and the relationship between magnetic properties and powder particle sizes was evaluated. The saturation magnetization Bs of the amorphous Fe82Si2B15C1 alloy was 1.62 T, which provided a superior dc-bias property for the powder cores. Meanwhile, a stable permeability up to high frequency range over 10 MHz and the low core loss of 400 kW/ma at f=50 kHz and Bm =0.1 T were obtained. These excellent high-frequency magnetic properties of the FeSiBC amorphous powder cores could be attributed to the effective electrical insulation between the FeSiBC amorphous powders made by mechanical crushing.

关键词： amorphous powder core mechanical crushing dc-bias property high frequency property

Magnetic Properties of Nanocrystalline Powder Cores Using Mechanically Crushed Powders

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2014年第3期21卷 348-351页

作者： Chun-bo HUANG tian-cheng liu Xiang-yue WANG Cao-wei LU De-ren LI Zhi-chao LU China Iron and Steel Research Institute Group R&D Center of Advanced Technology and Materials Co. Ltd.

Toroidal shape FeCuNbSiB nanocrystalline alloy powder cores were prepared by cold pressing using me- chanically crushed and ball-milled powders, respectively. The morphologies and their effects on the magnetic proper- ties of the compacted cores were investigated. Compared with ball-milled powders, mechanically crushed ones have more regular shapes and rounder edges, which lead to better inter-particle insulation. FeCuNbSiB nanocrystalline al- loy powder cores fabricated from mechanically crushed powders exhibit remarkably lower core loss of about 248.2 kW/m3 at 100 kHz for maximum flux density Bm 0.1 T, and more stable permeability up to 10 MHz. Moreover, the dc-bias property could be improved significantly using mechanically crushed powders.

关键词： nanocrystaUine powder core morphology core loss high frequency property

Exploring cyclic changes of the ocean carbon reservoir

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2003年第23期48卷 2536-2548页

作者： WANG Pinxian, tian Jun, cheng Xinrong, liu Quanlian & XU Jian Key Laboratory of Marine Geology, Ministry of Education, Tongji Uni-versity, Shanghai 200092, China Key Laboratory of Marine Geology Ministry of Education Tongji University

A 5-Ma record from ODP Site 1143 has re-vealed the long-term cycles of 400—500 ka in the carbon isotope variations. The periodicity is correlatable all over the global ocean and hence indicative of low-frequency changes in the ocean carbon reservoir. As the same periodicity is also found in carbonate and eolian dust records in the tropical ocean, it may have been caused by such low-latitude proc-esses like monsoon. According to the Quaternary records from Site 1143 and elsewhere, major ice-sheet expansion and major transition in glacial cyclicity (such as the Mid-Brunhes Event and the Mid-Pleistocene Revolution ) were all pre-ceded by reorganization in the ocean carbon reservoir ex-pressed as an episode of carbon isotope maximum (d 13Cmax), implying the role of carbon cycling in modulating the glacial periodicity. The Quaternary glacial cycles, therefore, should no more be ascribed to the physical response to insolation changes at the Northern Hemisphere high latitudes alone; rather, they have been driven by the 揹ouble forcing? a combination of processes at both high and low latitudes, and of processes in both physical (ice-sheet) and biogeochemical (carbon cycling) realms. As the Earth is now passing through a new carbon isotope maximum, it is of vital impor-tance to understand the cyclic variations in the ocean carbon reservoir and its climate impact. The Pre-Quaternary varia-tions in carbon and oxygen isotopes are characterized by their co-variations at the 400-ka eccentricity band, but the response of d 13C and d 18O to orbital forcing in the Quater-nary became diverged with the growth of the Arctic ice-sheet. The present paper is the second summary report of ODP Leg 184 to the South China Sea.

关键词：海洋 ODP 海洋钻探工程碳循环南中国海地层学

在线全文

学校读者我要写书评

暂无评论

空间站等离子体接触器钳位模式实验研究

推进技术 2017年第3期38卷 695-699页

作者：田立成刘明正杨威郭宁张天平刘士永兰州空间技术物理研究所真空技术与物理重点实验室甘肃兰州730000

为了研究等离子体接触器对空间站表面电位主动控制作用及钳位模式工作特性,对等离子体接触器进行了钳位模式实验研究,分析了空间站在运行轨道等离子体鞘层厚度,给出了等离子体接触器钳位电压和发射电流之间的变化规律,对真空度、等离子... 详细信息

为了研究等离子体接触器对空间站表面电位主动控制作用及钳位模式工作特性,对等离子体接触器进行了钳位模式实验研究,分析了空间站在运行轨道等离子体鞘层厚度,给出了等离子体接触器钳位电压和发射电流之间的变化规律,对真空度、等离子体密度、氙气流量等对钳位模式影响及等离子体接触器功率随发射电流变化规律进行了实验研究。实验结果表明:等离子体接触器在额定工作点下钳位电压低于20V;钳位电压增加使等离子体接触器发射电流突增;较低的真空度、较高的空间等离子体密度、较大的氙气流量会使等离子体接触器钳位模式较早出现,等离子体接触器电子发射特性曲线左移了近20%;等离子体接触器功率随发射电流增加而减小了近30%。

关键词：空间站等离子体接触器钳位模式实验研究

Research status and prospects of the fractal analysis of metal material surfaces and interfaces

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 20-38页

作者： Qinjin Dai Xuefeng liu Xin Ma Shaojie tian Qinghe Cui Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation University of Science and Technology BeijingBeijing 100083China Laboratory for Advanced Materials Processing of Ministry of Education University of Science and Technology BeijingBeijing 100083China School of Mechanical and Electrical Engineering Xinjiang Institute of EngineeringUrumqi 830023China

As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine *** analysis has been used to characterize the shapes of metal materials at various scales and *** methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and ***,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal *** the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear *** relationship between the fractal dimensions and properties of metal material surfaces and interfaces is *** from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be *** is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.

关键词： metal material surfaces and interfaces fractal analysis fractal dimension homogeneity

在线全文

学校读者我要写书评

暂无评论

甘氨酸高温热解含氮产物生成机理及实验研究

西北大学学报（自然科学版） 2016年第5期46卷 695-701页

作者：龚千代刘亮田红刘成艾锦瑾长沙理工大学能源与动力工程学院湖南长沙410114

以甘氨酸分子为研究对象,用密度泛函理论B3LYP/6-31G基组对甘氨酸热解过程中的各反应物、过渡态、中间体及产物进行了结构优化和频率计算,并采用热重红外联用仪对甘氨酸进行了实验。研究结果表明,初反应以R1-1,R1-2以及R2-1为主。其中R... 详细信息

以甘氨酸分子为研究对象,用密度泛函理论B3LYP/6-31G基组对甘氨酸热解过程中的各反应物、过渡态、中间体及产物进行了结构优化和频率计算,并采用热重红外联用仪对甘氨酸进行了实验。研究结果表明,初反应以R1-1,R1-2以及R2-1为主。其中R2-1为氨基的脱离,所以热解的最终含氮产物中NH3所占比例最大。随后的实验也证明了这一点。R1-1和R1-2为两分子脱水形成DKP的反应。该路径的次反应包括R1-8和R1-14,最终产物分别是HCN和HNCO,在实验的最终产物中也被检出。在初反应中占劣势的路径R3-1有两条次反应路径R3-3和R3-11,其中前者的焓变相对较小,是该路径上的主要反应。最后将实验结果与理论计算结果进行对比,发现吻合度较好。

关键词：甘氨酸高温热解密度泛函理论含氮产物热重红外联用

涎腺腺样囊性癌的细胞学诊断及其与基底细胞腺瘤的鉴别

在线全文

学校读者我要写书评

暂无评论

中华病理学杂志 2018年第4期47卷 279-283页

作者：白玉萍张勇田澄邢莉刘红刚首都医科大学附属北京同仁医院病理科头颈部分子病理诊断北京市重点实验室 100730

目的分析涎腺腺样囊性癌（ADCC）的细胞学形态特点，探讨涎腺ADCC与基底细胞腺瘤（BCA）的细胞学鉴别。方法回顾性分析首都医科大学附属北京同仁医院2010年1月至2017年1月头颈部30例涎腺ADCC及12例涎腺BCA的细胞学涂片／印片。除2例ADC... 详细信息

目的分析涎腺腺样囊性癌（ADCC）的细胞学形态特点，探讨涎腺ADCC与基底细胞腺瘤（BCA）的细胞学鉴别。方法回顾性分析首都医科大学附属北京同仁医院2010年1月至2017年1月头颈部30例涎腺ADCC及12例涎腺BCA的细胞学涂片／印片。除2例ADCC为针吸涂片外，余病例均为组织印片。所有病例诊断均经组织学证实。结果ADCC的肿瘤性导管细胞呈三维簇状、实性片状或单个散在分布；半透明黏液小球常见（20／30，66．7％）；细胞核呈圆形、卵圆形，有不同程度（多为轻度）的异型性；核仁常见（21／30，70．0％），部分病例核仁明显；瘤细胞胞质稀少。ADCC细胞核的异型性具体表现在：（1）核染色深，核染色质粗或略粗、分布不均；（2）细胞核略大，且大小不一；（3）细胞核形状有不同程度（常为轻度）的不规则。核分裂象少见，30例ADCC均未见坏死。BCA细胞学形态特点部分与ADCC重叠，其与ADCC的不同之处主要在于：（1）单个散在分布的肿瘤性导管细胞少见：（2）半透明黏液小球少见（1／12）；（3）细胞核染色浅或略深，形状规则一致、大小均一、无异型性，较ADCC者小且更为细长，无核仁或见不明显小核仁；（4）瘤细胞胞质较ADCC丰富。结论涎腺ADCC与BCA细胞学表现既相互重叠又各有特点，绝大多数病例可通过细胞学诊断、鉴别。半透明黏液小球是细胞学诊断ADCC的重要线索，但不是该肿瘤的特异性改变。肿瘤性导管细胞核的异型性是诊断ADCC的必要条件，也是鉴别ADCC与BCA可靠的细胞学指标。

关键词：涎腺肿瘤癌腺样囊性腺瘤细胞学技术

Preparation of FeCoNi medium entropy alloy from Fe^(3+)-Co^(2+)-Ni^(2+)solution system

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 92-101页

作者： Zongyou cheng Qing Zhao Mengjie Tao Jijun Du Xingxi Huang chengjun liu Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education) Northeastern UniversityShenyang 110819China School of Metallurgy Northeastern UniversityShenyang 110819China Engineering Research Center of Frontier Technologies for Low-carbon Steelmaking(Ministry of Education) Shenyang 110819China

In recent years,medium entropy alloys have become a research hotspot due to their excellent physical and chemical *** controlling reasonable elemental composition and processing parameters,the medium entropy alloys can exhibit similar properties to high entropy alloys and have lower *** this paper,a FeCoNi medium entropy alloy precursor was prepared via sol-gel and coprecipitation methods,respectively,and FeCoNi medium entropy alloys were prepared by carbothermal and hydrogen *** phases and magnetic properties of FeCoNi medium entropy alloy were *** showed that FeCoNi medium entropy alloy was produced by carbothermal and hydrogen reduction at 1500℃.Some carbon was detected in the FeCoNi medium entropy alloy prepared by carbothermal *** alloy prepared by hydrogen reduction was uniform and showed a relatively high ***,the hydrogen reduction product exhibited better saturation magnetization and lower coercivity.

关键词： medium entropy alloy sol-gel co-precipitation carbothermal hydrogen reduction