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Calculation of Resistivity of the Insulating Layer in Tunnelling-Magnetoresistive Head by Fast Green Function Method

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Chinese Physics Letters 2005年第8期22卷 2063-2065页

作者：韦丹朴琨秦健董仲 LabofAdvancedMaterials Dept.ofMaterialsScienceandEngineeringTsinghuaUniversityBeijing100084

We calculate the resistivity of the insulating layer in a tunnelling-magnetoresistive (TMR) magnetic head by using the Landauer–Büttiker formula with a fast Green function method, where a recursive process with a faster simulation speed and higher accuracy is carried out to substitute the inversion of Green's matrix. A tight-binding model with an energy barrier ΔE is utilized to simulate the magnetoresistive tunnelling junction in the TMR head. The resistivity of the insulating layer is 2.6×105μΩcm with two oxygen-ion layers and ΔE = 2.5eV, which agrees with the experimental data.

关键词： GMR FM TMR

Electrochemical and Reaction Bonding Processing of Thick ZrO_2/Al_2O_3 Composite Coatings

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材料热处理学报 2004年第5B期25卷 1068-1071页

作者： WANGZhou-cheng XIAOPing Dept.ofmaterialsscienceandengineering XiamenUniversityXiamenChina ManchesterMaterialsScienceCentre UniversityofManchesterManchesterUK

A novel technique combining electrophoretic deposition (EPD) and reaction bonding process (RBP) is developed to fabricate thick ZrO2/Al2O3 composite coatings. Mixed organic solvents are used here to make suspension containing yttria stablised zirconia (YSZ) and aluminium (Al). The results show that densely packed green form coatings are deposited using a mixture of ethanol and acetylacetone as suspension medium and ball milling for 48 hours. On subsequent heat treatment, melting and oxidation of aluminium in the green forms promote densification during sintering. By these means, thick, uniform and crack-free ZrtVA^Oa composite coatings have been fabricated on metal substrate.

关键词：电泳沉积复合涂层 ZrO2 Al2O3 RBP

CVD preparation of vertical graphene nanowalls/VO_(2)(B)composite films with superior thermal sensitivity in uncooled infrared detector

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Journal of Materiomics 2020年第2期6卷 280-285页

作者： Ya Lu Han Zhang Dongyun Wan School ofmaterialsscienceandengineering ShanghaiUniversityShangdaRd.99BaoshanShanghai200444China

Vanadium dioxide with superior thermal sensitivity is one of the most preferred materials used in microbolometer,and the B phase of VO_(2) is particularly ***,conventional VO_(2)(B)undergoes low temperature-coefficient of resistance(TCR)values and large *** this paper,simple controllable composite films of vertical graphene nanowalls/VO_(2)(B)(i.e.,VGNWs/VO_(2)(B))with a suitable square resistance(12.98 kU)and a better temperature-coefficient of resistance(TCR)(-3.2%/K)were prepared via low pressure chemical vapor *** VGNWs can provide a fast channel for electron transport and enhance the conductivity of VO_(2)(B).This preparation method can provide a low cost,facile and simple pathway for the design and fabrication of high performance VO_(2)(B)thin films with superior electrical properties for its application in uncooled infrared detectors.

关键词： Vertical graphene nanowalls VO_(2)(B)films Chemical vapor deposition Uncooled infrared detectors

Analyses on Ignition-Proof Mechanics of AZ91D Alloy Added with Ce

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Journal of Materials Science & Technology 2002年第3期18卷 279-280页

作者： XiaofengHUANG HongZHOU 等 Schoolofmaterialsscienceandengineering HarbinInstituteofTechnologyHarbin150001China Dept.ofmaterialsscienceandengineering JilinUniversityChangchun130025China

Theoretical analysis on ignition-proof of AZ91D alloy added with Ce was studied. The effect of Ce on burning temperature was investigated. The burning temperature increases with increasing Ce by insulation work at different temperatures. The influence of Ce on maximum insulation work time was also studied. The maximum insulation work time increases with increasing Ce and decreases with the melting temperature. There is a tendency for Ce to concentrate on the surface of *** AZ91D alloy. Ce will react with MgO and O2. The resultant will fill the cavity of MgO film to form multifilm. So the density of surface film of liquid Mg will increase to prevent burning.

关键词： AZ91D alloy Rare earths(Ce) Burning point Ignition-proof mechanism

Impact of high dose Kr^+ ion irradiation on the corrosion behavior and microstructure of Zircaloy-4

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Journal of University of Science and Technology Beijing 2005年第2期12卷 178-181页

作者： QianWan XindeBai XiaoyangLiu Dept.ofEngineeringPhysics TsinghuaUniversityBeijing100084China Dept.ofmaterialsscienceandengineering TsinghuaUniversityBeijing100084China

In order to investigate the ion irradiation effect on the corrosion behavior and microstructure of Zircaloy-4, the Zircaloy-4 film were prepared by electron beam deposition on the Zircaloy-4 specimen surface and irradiated by Kr ions using an accelerator at an energy of 300 keV with the dose from 1×1015 to 3×1016ions/cm2. The post-irradiation corrosion tests were conducted to rank the corrosion resistance of the resulting specimens by potentiodynamic polarization curve measurements in a 0.5 mol/L H2SO4 water so- lution at room temperature. Transmission electron microscopy (TEM) was employed to examine the microstructural change in the surface. The potentiodynamic tests show that with the irradiation dose increasing, the passive current density, closely related to the surface corrosion resistance, decreases firstly and increases subsequently. The mechanism of the corrosion behavior transformation is due to the amorphous phase formation firstly and the amorphous phase destruction and the polycrystalline structure formation in the irradiated surface subsequently.

关键词： Zircaloy-4 irradiation damage corrosion resistance, structure transformation

FEM Simulation of Effect of Process Parameters on Static Recrystallization in 60SiMnA Spring Steel

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Journal of Materials Science & Technology 2004年第3期20卷 257-260页

作者： JiaheAI TongchunZHAO HuijuGAO XishanXIE Dept.ofmaterialsscienceandengineering TsinghuaUniversityBeijing100084China SchoolofMaterialsScience&Engineering.UniversityofScience&TechnologyBeijing Beijing100083China

Two-dimensional rigid-plastic finite element method (FEM) was used for simulation of the effect of process parameterson the static recrystallization of 60SiMnA spring steel using MARC/AutoForge 3.1 software. A thermo-mechanicalcoupled analysis was conducted considering the heat transfer between the workpiece, the roll and the environment,and the heat generation due to plastic work. The static recrystallization laws under different processing conditionsand the predicted distribution of the static recrystallization volume fraction on the deformation cross section arepresented.

关键词： 60Si2MnA spring steel Rigid-plastic FEM Thermo-mechanical coupling Static recrystallization

Effect of Al Content on Precipitation of α_2 Ordered Phase in Ti-Al-Sn-Zr-Mo-Si-Nd Alloys

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Journal of Materials Science & Technology 2002年第3期18卷 245-247页

作者： JunZHANG DongLI Dept.ofmaterialsscienceandengineering ShenyangUniversityShenyang110044China InstituteofMetalResearch ChineseAcademyofSciencesShenyang110016China

The precipitation characteristics of the α2 ordered phase in Ti-AI-Sn-Zr-Mo-Si-Nd alloys with various content of Al, under different aging conditions, were investigated. The distribution and size of the α2 ordered phase changed with temperature and Al content. The dislocations were the only places where the α2 ordered phase could precipitate at higher temperature near the critical transformation temperature for each alloy experimented. With the addition of Al content, the critical transformation temperature of α2 ordered phase increased. When the aging temperature was relatively low (650℃), the precedent precipitation of α2 ordered phase took place in primary a phase at the early stage of aging, in the duplex microstructure (the primary a with the transformed (3) of the alloys with lower Al content. But after certain aging time (50 h), the size of α2 particles was almost equal in both the primary a and the transformed β. And no obvious growth of α2 particles could be observed after 50 h.

关键词： Ti-Al-Sn-Zr-Mo-Si-Nd alloys α2 ordered phase Precipitation

Relations of abrasion resistance and hardness of 16Cr-3C white irons with retained austenite content

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Journal of University of Science and Technology Beijing 2004年第6期11卷 539-544页

作者： ZhipingSun RulinZuo CongLi BaoluoShen ShengjiGao SijiuHuang Schoolofmaterialsscienceandengineering SichuanUniversityChengdu610065China School.ofmaterialsscienceandengineering ChongqingUniversityChongqing400044China NationalKeyLaboratoryforNuclearFuelandMaterials NuclearPowerInstituteofChinaChengdu610041China SijiuRareEarthAlloyFoundry Shuangliu610211China

The relationship between the retained austenite content of the matrix in16Cr-3C white irons and the abrasion resistance was investigated. The results show that: (1) theabrasion resistance can be improved by sub-critical heat treatment, which could be attributed to thedecrease of the retained austenite content; (2) both the abrasion resistance and hardness can beimproved by controlling the retained austenite content below 20 percent-30 percent and arrive at themaximum when the retained austenite content is reduced to about 10 percent; (3) the abrasionresistance decreases abruptly once the retained austenite content is lower than 10 percent, whichstems from both the in situ transformation of (Fe, Cr)_(23)C_6 to M_3C carbides and the formation ofpearlitic matrix.

关键词： retained austenite abrasion resistance hardness white iron

A Novel and Fast Model of Erbium-doped Fiber Amplifiers

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Semiconductor Photonics and Technology 2000年第1期6卷 1-7页

作者： ZHUZhi－peng JIANGFeng－xian dpet.ofElectr.Eng. FudanUniversityShanghai200433CHN dpet.ofElectr.Eng. FudanUniversityShanghai2004

A novel and fast model of erbium-doped fiber amplifiers (EDFAs) is presented. By calculating a typical EDFA, numerical results are compared with the results obtained by spectral-solved method. The results of comparison show that such a model can improve the computational speed and preserve the precision. Some characteristics of the EDFA are then analyzed using this model. The results are consistent with those of the experiments.

关键词： Erbium-doped fiber amplifier Rate equation Optical communications