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The crossover from parallel shift to fan-shape broadening of the superconducting transition of La(1.44)Nd(0.4)Sr(0.16)CuO(4) films in magnetic fields

Superconductor Science & Technology

In this paper we report the transport properties of c-axis-oriented superconducting La(1.44)Nd(0.4)Sr(0.16)CuO(4) films on LaSrAlO(4) substrates with different thicknesses in various magnetic fields parallel and perpendicular to the c axis of the films. It is found that with decreasing film thickness there is a crossover from the parallel shift to fan-shape broadening in the resistive transitions. Moreover, for both field configurations, the flux pinning potential U(0)(H) of the film shifts upward with an order of magnitude with increasing in-plane compressive strain. These results indicate that the compressive epitaxial strain and strain-induced destabilization of the static charge stripes are important aspects for the promotion of superconducting transition temperature as well as the flux pinning potential.

关键词: high-temperature superconductors;crystal thin-films;flux motion;la2-xsrxcuo4;strain;insulator;dependence;behavior

BEHAVIOUR OF Ti IN AS-CAST MEDIUM MANGANESE AUSTENITIC STEEL

JIANG Qichuan LI Zhang WANG Shoushi HE Zhenming Jilin University of Technology , Changchun , China

金属学报(英文版)

The majority of Ti is found to be preferentially precipitated in the form of TiC from medium manganese steel melt.The TiC may contribute to the heterogeneous nuclei of fine austenite crystallization,to the retardation of dislocation movement as well as to pile-up and proliferate the dislocations,thus,the matrix of the as-cast steel will be effectively strength- ened.It was also found that the TiC can be acted as the heterogeneous nuclei of the nodular eutectic carbide formation and caused the dispersion o fan abundance of the carbide in the interstices between austenite dendrite arms.

关键词: TiC , null , null

A single-phase spindle motor design for DVD application

D.R.Huang , T.F.Ying , L.T.Kuo , S.J.Wang , H.C.Huang , C. Y.Huang

材料科学技术(英)

A single phase brushless spindle motor with innovative design has been developed for application in a DVD drive. The methods used to reduce the cogging torque and to improve the dynamic performance of this new design motor are proposed in this paper. The single phase brushless spindle motor is usually applied for cooling fan, pump and blower before the performance is improved by the reengineering process. The stator configuration and the drive circuit have been remodeled in order to meet the requirements of the spindle motor used in the DVD applications.

关键词:

Numerical Simulation of Temperature Field of Die Casting Dies

Xiang XUE , Zhiliang NING , Bide ZHOU , Chunhui ZHANG

材料科学技术(英)

In this study, the Solidworks was used as pre-processor, which performed the three- dimensional solid construction and automatic enmeshment. The COSMOS was adopted as post- processor to display the temperature distribution and further to simulate the thermal stress distribution of dies. A software package for three-dimensional temperature fields of complicated die casting and its dies was developed and the temperature distributions of a fan cover casting were simulated by the software.

关键词:

紫外光固化罩光漆用环氧丙烯酸酯树脂的合成及应用

陈云传 , 刘晓亚 , 熊万斌 , 陈明清 , 李华伟

材料保护 doi:10.3969/j.issn.1001-1560.2003.11.008

以酚醛型环氧树脂为原料,合成出低粘度环氧丙烯酸酯(EA)树酯,讨论了环氧树脂类型、催化剂用量等因素对反应及产物性能的影响,并用柔性单体--己内酯改性丙烯酸酯(FAn)替代通常的单官能度单体,对树脂产物进行了涂料配方的研究.

关键词: 紫外光(UV)固化 , 罩光涂料 , 环氧丙烯酸树脂 , 应用

Large magnetoresistance over an entire region from 5 to 380 K in double helical CoMnSi compound

Journal of Physics D-Applied Physics

A large magnetoresistance (MR) is observed in a double helical CoMnSi compound over the entire temperature region from 5 K to the maximum measuring temperature of 380 K, with the largest MR ratio of -18.3% at 245 K and the smallest MR ratio of -5.5% at 85 K at 5 T. This phenomenon is ascribed to two different mechanisms in different temperature regions. The suppressed spin fluctuations of the double helical structure are responsible for the MR below 110 K. However, in consideration of the natural multilayer superstructure of CoMnSi, the larger MR above 110 K is ascribed to the decrease in K-space restrictions when the change in magnetic structure from double helical order to fan order occurs.

关键词: giant magnetoresistance;magnetic-structure;crystal;metals

A novel design of single-chamber SOFC micro-stack operated in methane-oxygen mixture

Electrochemistry Communications

In this paper, a novel design of single-chamber solid oxide fuel cell (SC-SOFC) micro-stack with star-shape was presented and operated successfully in methane-oxygen mixture. This stack consisted of four anode-supported single cells connected in series, and generated a maximum power output of 421 mW (total active area: I cm(2)) at the furnace temperature of 750 degrees C, which powered an USB fan stably. The symmetric design can ensure the identical operation of each cell, and good capacity for scale-up of the stack. (C) 2008 Elsevier B.V. All rights reserved.

关键词: Solid oxide fuel cell;Single-chamber operation;Micro-stack;Methane-oxygen mixture;oxide fuel-cell;high-power-density;electrolyte;performance

Intensified alkaline leaching pretreatment of refractory gold concentrates at common temperature and pressure

Transactions of Nonferrous Metals Society of China

A new process for the hydrometallurgy of refractory gold concentrates was presented. The process comprises grinding-leaching, intensified alkaline leaching (IAL), cyanidation and adsorption. In a stirring-type pulverizing-leaching tower mill, the concentrate is ground to <35. 6 μm of 95. 5 % while simultaneously leached by NaOH of 12 kg/t, then carried out intensified alkaline leaching for 48 h by NaOH of 108 kg/t in enhanced agitation tanks with the pulp concentration of 40% solids at the environmental temperature of 9. 5 &SIM; 13. 5 &DEG;C and the environmental pressure of 10(5) Pa. The oxidation rate of As is 94. 9%, and 47. 6% for S. The total consumption of NaOH is only 20% of that theoretically calculated under the conditions of full oxidation at the same oxidation rates of arsenic to arsenate and sulfur to sulfate. The gold leaching rate by NaCN in 24 h is increased from 9. 2% before pretreatment to 94. 2%. The consumption of NaCN is 7. 5 kg/t, which is one times less than that before pretreatment. The extraction cost of gold is about 422 Yuan/t.

关键词: refractory gold concentrates;grinding-leaching;intensified alkaline;leaching (IAL);pretreatment;common temperature and pressure

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