高磷含量CoP-Cu复合丝巨磁阻抗效应的频谱特性

控制电化学工艺条件在直径为200μm的铜丝表面合成CoP磁性镀层成功地制备出高磷含量CoP—Cu复合丝巨磁阻抗效应材料。当磷含量为20%（原子分数）时,复合丝巨磁阻抗效应非常显著,达80%以上。本文详细研究了复合丝材料的频谱及巨磁阻抗效应频谱,指出复合丝巨磁阻抗具有较低的特征频率及较宽的频率使用范围与此新型结构有关,本文还发现,随频率的增加,最大负巨磁阻抗比对应的外加直流磁场也在增加,并且在高频与低频时,巨磁阻抗效应随磁场的响应曲线明显不同。     

Fe基纳米晶粉芯磁致频移特性的研究

测量了Fe基纳米晶粉芯线圈与电容并联成LC回路的共振频率 (fr) ,研究了fr 随外加磁场变化的特性 ,发现fr 随外加磁场有显著变化。在 0— 5 6kA m范围内有很好的线性和灵敏度 ,可以用于磁场测量     

水热法合成ZnAl2O4及其湿敏性能研究

以Al2(SO4)3和Zn(NO3)2为原料,采用水热法合成铝酸锌微粉体,通过扫描电镜和XRD分析发现ZnAl2O4晶型良好,粒径小,呈纤维状均匀分布;进一步研究湿敏特性,结果表明:测试频率对阻抗-相对湿度(RH)特性曲线影响较大,阻抗随频率的增加而迅速减小,10KHz时在33%～95%的范围内曲线的线性度好,在相同的湿度下,试样的电容随频率的增加而减小,在低频100HZ下,电容随相对湿度的升高而增大。     

超磁致伸缩驱动器磁滞非线性数值模拟研究

针对超磁致伸缩驱动器(giant magnetostrictive actuator,GMA)具有磁滞非线性现象,以经典Jiles-Atherton模型为基础,建立了包含偏置磁场强度和预压应力的GMA磁滞非线性模型,进行了数值仿真分析,得到了偏置磁场强度和预压应力对GMA磁化强度曲线和磁致伸缩应变曲线的影响规律。结果表明,偏置磁场强度对磁化强度曲线和磁致伸缩应变曲线的形状影响较大,调整偏置磁场强度的大小,可改变磁化强度曲线的线性区间,并能抑制或消除磁致伸缩应变曲线的倍频效应;预压应力对磁化强度曲线和磁致伸缩应变曲线的形状影响较小,施加不同的预压应力,可改变磁化强度曲线和磁致伸缩应变曲线的变化率。这与现有试验得到的结论相吻合,验证了所建磁滞非线性模型的合理性。     

低温应力退火Fe基合金薄带巨磁阻抗特性的研究

通过同步辐射X射线衍射技术,观测Fe73.5Cu1Nb3Si13.5B9非晶薄带经过不同温度和不同应力退火60 min后样品的微观结构,利用HP4294A型阻抗分析仪测量相应样品的巨磁阻抗比与磁各向异性。研究结果表明,在450℃下施加不同应力退火的样品仍然处于非晶结构状态,并且在应力为112.1 MPa的条件下产生优异的磁性能,样品的最大巨磁阻抗比达到了1818.7%,是自由退火条件下最大巨磁阻抗比的1.9倍,同时能够改变巨磁阻抗曲线的形状,使Fe基合金薄带的巨磁阻抗曲线具有宽线性的特性。对实验数据进行拟合后发现,样品的最大巨磁阻抗比和磁各向异性场与外加应力都具有线性关系,磁感灵敏度与外加应力具有负指数关系。通过探究发现具有非晶结构的Fe基合金薄带的磁学性能对应力敏感,可以作为研究非晶纳米晶合金材料应力敏感问题的另一个新方向。     

纳米晶FeCuNbSiB多层膜的巨磁阻抗效应研究

研究了纳米晶态下Fe73.5Cu1Nb3Si13.5 B9多层膜的巨磁阻抗(GMI)效应。研究结果表明纵向巨磁阻抗(LMI)效应在3MHz时取得最大值为44％,横向巨磁阻抗(TMI)效应在6MHz时取得最大值为46％。LMI与TMI随外磁场有不同的变化行为,TMI曲线具有阁值行为,超过阈值磁场后出现明显的磁阻抗效应。晶化后出现最大值阻抗效应所对应的频率下降,由非晶态下的13MHz下降为晶化后的3MHz。薄膜样品的磁阻抗效应与样品中磁矩的空间分布密切相关．磁矩垂直面向分布时。磁阻抗效应下降为5％     

环境温湿度对压磁柔性薄膜力敏性能的影响

以粉体含量为83.3%(质量分数)、薄膜厚度为200μm的FeCuNbSiB非晶粉/硅橡胶复合薄膜为研究对象,通过控制薄膜所处的外界环境温湿度,系统研究了环境温湿度的改变对压磁柔性薄膜力敏性能的影响,从而为以压磁柔性薄膜为核心元件的压磁式传感器的应用开发提供有价值的参考。实验结果表明,环境温湿度变化对FeCuNbSiB非晶粉/硅橡胶复合薄膜的力敏性能有较大影响。随着环境温湿度的升高,灵敏度|ΔZ|和应力阻抗效应SI%呈折线变化趋势。频率为1kHz时,|ΔZ|和SI%的变化幅度最大,随着频率升高,|ΔZ|和SI%的变化幅度减小;在环境温度为25℃,湿度为40%RH条件下,FeCuNbSiB非晶粉/硅橡胶复合薄膜具有最佳的力敏性能。在频率为1kHz,压应力为0.13和1MPa条件下,|ΔZ|和SI%值的变化幅值分别高达827.37kΩ和37.36。     

巨磁阻抗效应的非对称特性

巨磁阻抗效应的应用需要传感器具有好的线性度和高的灵敏度,实现非对称巨磁阻抗效应可以使传感器在零场附近提高灵敏度和改善线性度.本文对近年来非对称巨磁阻抗效应的研究进展进行了综述,并分析了其产生的机理.     

一种新型的纳米巨磁阻抗磁敏传感器

主要介绍纳米微晶材料的巨磁阻抗效应及利用该效应研制的一种新型的磁敏传感器.它以脉冲频率的方式作为输出结果,与传统的磁敏传感器相比,具有高灵敏度、便于数字化测量等优点,在地磁测量、磁航向等方面有良好的应用前景.     

NiO/FeCo磁性多层膜的高频磁性

制备了一系列具有铁磁/反铁磁交换偏置作用的[NiO/Fe65Co35]10多层膜,使用振动样品磁强计(VSM)测量了样品的静磁参数,利用微带线法测量了样品4GHz-10GHz的磁谱,首次制备并测得了自然共振频率(fr)在6GHz以上,最高到fr=9.6GHz的薄膜样品。结果表明交换偏置场(Hex)、各向异性场(Hua)、以及矫顽力(Hc)随铁磁层厚度(tFM)增大而减小;基于Landau-Lifishitz(L-L)方程对静磁参量和磁谱进行了比较,发现样品自然共振频率较L-L方程计算值偏大30%以上。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.