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Bonded Terfenol-D composites with low eddy current loss and high magnetostriction

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Rare Metals 2010年第6期29卷 579-582页

作者： TIAN Jianjun,ZUO Zhijun,PAN De’an,and ZHANG Shengen School of materials science and engineering,university of science and technology beijing,beijing 100083,china School of materials science and engineering University of Science and Technology Beijing Beijing China

Bonded Terfenol-D composites,with high electrical resistivity and low eddy current loss,can be used in an alternating magnetic field with high ***,the nonmagnetic binder impairs the magnetostriction of the *** achieve high magnetostriction and low eddy current loss,the mixture of the alloy powder and binder was compressed at low pressure in an oriented magnetic *** this,the aligned samples were recompressed by cold isostatic pressing（CIP）.Besides,the effect of particle size on the magnetostriction of the bonded Terfenol-D composites was also *** results showed that the bonded Terfenol-D composites had excellent magnetostriction when the particle size was 50-80 μ*** oriented magnetic field and CIP could improve the magnetostriction of the bonded composites,which reaches 1020×*** bonded Terfenol-D composites had good compact structure and high density（7.24 g/cm3）.The magnetic loss of the bonded Terfenol-D composites was 192 mW/cm3 at a frequency of 100 kHz in a magnetic field of 960 A/m,which was about one third of that of casting Terfenol-D alloys.

关键词： composites Terfenol-D magnetostriction eddy current losses density

Producing Calcium-Bearing Mullite Thermal-Insulating Refractories by Kyanite

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International Journal of Minerals,Metallurgy and materials 1999年第1期13卷 50-53页

作者： Wen Ni (Resources engineering School, university of science and technology beijing, beijing 100083, china) Resources engineering School University of Science and Technology Beijing Beijing 100083 China

To improve the physical properties, a series of experiments have been camed out to produce calcium-bearing mullite thermal-insulating refractories by using kyanite as major raw materials. The experiments were carried out by a foaming technique and using white cement as a combing agent. The results show that the calcium-bearing mullite refractory has much better physical properhes than traditional clay refractory and high-alumina refractory.

关键词： mullite thermal-insulating refractory kyanite

A New Safety Electric Initiating System

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International Journal of Minerals,Metallurgy and materials 1999年第4期13卷 306-308页

作者： Daze Lin(Resource engineering School, university of science and technology beijing, beijing 100083, china) Univ of science and technology Beijing Beijing China

Based on the analysis of weakness on the safety of traditional electric detonators, a BJ-l safety electric detonator initiatingsystem and its corresponding safe examination technique were successfully developed. By leading false foot wires and taking advantageof the transmitting frequency band of Mo-Zn ferrite, detonators in this new system can completely impede the direct induction of outsidecrosstalk that may cause casual firing in the ordinary as well as eleclromagnetic ones. Possible causality by lightning was discussed. Results are presented, of its safety tests on resistance to direct and alternating current, electrostatic, and crosstalk induced by damp leakagein saturated salty water.

关键词： electric detonator blasting engineering, electric initiating system, safety

Theorems for Testing Local Activity of CNN and Application to Cardiac Purkinje Equations

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International Journal of Minerals,Metallurgy and materials 2000年第2期14卷 139-146页

作者： Lequan Min(Applied science School, university of science and technology beijing, beijing 100083, china) Applied science School University of Science and Technology Beijing Beijing 100083 China

The theorems for testing the local in one-port cellular neural/inear network (CNN) cells with four local state variables are presented. Using the theorems computes the bifurcation diagrams of the cardiac Purkinje fiber (CPE) equations Which describethe long-lasting action and pace-maker potentials of the Purkinje fiber of the heart. The computer simulation shows that periodic trajectories or convergent trajectories of the CPF Equations can be foun if the cormsponing cell Parameters are located in a positive domainbut nearby edge of chaos. In particular a heart with approximate normal frequency of heartbeat but non-normal electrocardiogram maysuddenly stop by slightly perturbing the parameters of the corresponding CPF Equations when the Paramders are located nearby the edge of chaos in the bifurcation diagrams. This research seems to interpret reasonbly the phenomena that patients with cardiac diseases might suddenly die without warning.

关键词： cellular neural network local activity cardiac Purkinje fiber heartbeat

Relationship between Low Temperature Toughness and Microstructure in Low Activation Fe-Cr-Mn(W,V)Steel for Fusion Reactors

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International Journal of Minerals,Metallurgy and materials 1999年第2期13卷 111-115页

作者： Benfu Hu Chengchang jia(Material science and engineering School, university of science and technology beijing, beijing 100083, china) Material science and engineering School University of Science and Technology Beijing Beijing 100083 China

Fe-Cr-Mn (W, V) austenite steel was researched in order to supply a theory base for the first wall materials of fusion *** included vacuum melting, forging, annealing, solution treatment, Charpy impact tests and microstructure observation. Theresults show that the imped value decreases with the test temperature decreasing. In this system, there is ductile/brittle transition. Themechanism of this decrease of the impact value is considered to be due to γ - ε transformation in sub-stable austenite steel and stoppingoverlapping sacking fault by grain boundaries in stable austenite steel.

关键词： fusion reactor first wall materials low temperature toughness Fe-Cr-Mn system

Phenomenological Modeling of Warm Compaction and Experimental Verification

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International Journal of Minerals,Metallurgy and materials 2000年第4期14卷 292-295页

作者： Shiju Guo, Tao Lin (Material science and engineering School, university of science and technology beijing, beijing 100083, china) Material science and engineering School University of Science and Technology Beijing Beijing 100083 China

A phenomenological modeling approach to establishing the warm compaction equation and curves by modifying the regression equation of the room-temperature compaction curve is presented. An enhanced factor of compacting pressure is introduced into the equation in order to reveal the effects of powder/die temperature and filling height of powders on green density. Compaction curves yielded from this equation are consistent with the experimental data of ATOMET grade iron powders. The curves show that the powder/ die temperature should reduce as the filling heights of powders increase and that in some cases warm compaction can not give rise to a higher green density.

关键词： powder metallurgy warm compaction compaction equation materials

Wear characteristics of spheroidal graphite roll WC-8Co coating produced by electro-spark deposition

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Rare Metals 2010年第2期29卷 174-179页

作者： WANG Jiansheng, MENG Huimin, YU Hongying, FAN Zishuan, and SUN Dongbai School of materials science and engineering, university of science and technology beijing, beijing 100083, china School of materials science and engineering University of Science and Technology Beijing

Electro-spark deposition（ESD） was adopted for preparing high property coatings by depositing WC-8Co cemented carbide on an spheroidal graphite roll *** microstructure and properties of the coating were investigated by X-ray diffraction（XRD）, scanning electron microscopy（SEM） with energy dispersive X-ray（EDX） and ball-disc configuration wear *** results show that nanosized particles and amorphous structures prevail in the coating which is metallurgically bonded to the *** microstructures of the transition zone include columnar structure and equiaxed *** primary phases of the coating contain W2C, W6C2.54, Fe3W3C, and *** results of abrasive test show that the coating has low friction coefficients（μaverage = 0.18） and the wear mechanisms are mainly abrasive wear, fatigue wear, and oxidation *** maximum microhardness value of the coating is about 17410 N/*** study reveals that the electro-spark deposition process has better coating quality and the coating has high wear resistance and hardness.

关键词： electro-spark deposition WC/Co coatings wear resistance microstructure

Annealing Texture Evolution of Ti-IF Steel during Batch Annealing

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International Journal of Minerals,Metallurgy and materials 1998年第3期12卷 175-179页

作者： Jing Shi Xianjin Wang(Material science and engineering School, university of science and technology beijing, beijing 100083, china) Material science and engineering School University of Science and Technology Beijing Beijing 100083 China

Texture development and recrystallization behavior of Ti-IF steel during Batch Annealing (BA) were investigared with X-ray diffraction and EBSP in lab, and the results were compared with research work on continu ous annealing (CA) with rapid heating rate. The basic tendencies are similar that eary nucleation takes place in ND fibers, RD fibers are consumed at the end of recrystallization, and ND texture dominates over annealing texture. However, the detailed texture transformation during batch annealing is different and somewhat more compicated than tha in rapid-heating process. Moreover, misorientation plays an important role in texture transformation of BA In addition, the results of EBSP are consistent with that of ODF well.

关键词： Ti-IF steel texture batch annealing X-ray diffraction EBSP

Slurry Preparation and Rolling of Semi-solid 60Si2Mn Spring Steel

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Journal of materials science & technology 2003年第6期19卷 613-616页

作者： Weimin MAO, Aimin ZHAO, Dong YUN, Leping ZHANG and Yonglin KANGSchool of materials science and engineering, university of science & technology beijing, beijing 100083, china Sch. of Mat. Sci. and Eng. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The nondendritic semi-solid slurry preparation of 60Si2Mn spring steel has been studied in this paper. The experiments have shown that when stirred for 2 min on the test condition, the semi-solid slurry with 50%-60% fraction solid and spherical primary austenitic grains in the size of 100-300 μm can be obtained and is easy to be discharged from the bottom little hole of the stirring chamber. The nondendritic slurry of 60Si2Mn spring steel can be rolled into given plate form successfully, but the solid phase and liquid phase is easy to be separated in rolling process so that the solid primary austenite is concentrated in the center and the liquid is near the edge of the rolled plate. The rupture strength and elongation of the plate rolled only once with semi-solid slurry are lower than that of the traditionally repeated hot-rolled plate of 60Si2Mn spring steel.

关键词： 60Si2Mn Semi-solid Electromagnetic stirring Rolling