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1.
用旋转水中纺丝法制成几种不同直径的(Co0.94Fe0.06)72.5Si12.5B15非晶丝,对丝进行张力退火后,测试了非晶丝热处理前后的磁阻抗性能。结果表明制成的非晶丝具有明显的巨磁阻抗效应,且巨磁阻抗效应随电流频率不同而表现出正磁阻抗和负磁阻抗两种规律。张力退火对正磁阻抗效应有明显改善,而且对直径小的试样,阻抗对轴向外磁场变化的灵敏度更高。实验得到的最大灵敏度为124%/Oe。  相似文献   

2.
采用磁控溅射方法在玻璃基片上制备了FeSiB/Cu/FeSiB多层膜,在100kHz~40MHz范围内研究了FeSiB薄膜厚度对FeSiB/Cu/FeSiB多层膜巨磁阻抗效应的影响。当磁场施加在薄膜的纵向时,巨磁阻抗效应随磁场的增加而增加,在某一磁场下达到最大值,然后随磁场的增加而下降到负的巨磁阻抗效应。当FeSiB薄膜的厚度为1.8μm时,在频率3.2MHz、磁场2.4kA/m时,多层膜巨磁阻抗效应达最大值13.5%;在磁场为9.6kA/m时,巨磁阻抗效应为-9.2%。然而,当FeSiB薄膜的厚度为1μm时,多层膜的巨磁阻抗效应在频率40MHz、磁场1.6kA/m时达最大值5.8%。另外,当磁场施加在薄膜的横向时,薄膜表现出负的巨磁阻抗效应。对于膜厚为1.8μm的FeSiB薄膜,在频率5.2MHz、磁场9.6kA/m时,巨磁阻抗效应为-12%。可见巨磁阻抗效应的最大值及负的巨磁阻抗效应与多层膜中磁各向异性轴的取向及FeSiB薄膜的厚度有关。  相似文献   

3.
秦宏伟 《功能材料》2000,31(1):40-41
详细研究了Fe84Zr7B9薄带中的巨磁阻抗效应。研究了退火工艺对巨磁阻抗效应的影响。发现600℃退火20min的Fe84Zr7B9薄带在1.5MHz下的(Zmax(H)-Z(5200A/m)/Z(5200A/m)达到152%。同时我们还测量磁导率随磁场的变化关系,研究了不同退火工艺下材料的磁导率,发现材料磁导率值与巨磁阻效应的大小紧密相关。  相似文献   

4.
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%  相似文献   

5.
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。  相似文献   

6.
姚素薇  赵洪英  张卫国  段月琴  王宏智 《功能材料》2005,36(7):1005-1007,1010
采用脉冲电沉积工艺在直径为200μm的铜丝表面沉积铁镍合金镀层,形成具有同轴电缆结构的巨磁阻抗复合丝材料。分别改变复合丝磁性外壳厚度与铜丝直径,研究复合丝结构对巨磁阻抗效应的影响。发现巨磁阻抗比值随磁性外壳厚度的增大及铜丝直径的增大而增大,特征频率则向低频端移动。本文还发现在外加直流磁场低于5.57kA/m时,驱动交流电幅值增大,巨磁阻抗效应增大;高于5.57kA/m时,驱动交流电幅值的大小几乎不再影响复合丝的巨磁阻抗效应。在驱动电流上叠加20mA以下的直流偏置对巨磁阻抗效应没有影响。  相似文献   

7.
FeSiB/Cu/FeSiB多层膜巨磁阻抗效应研究   总被引:2,自引:0,他引:2  
用磁控溅射法在玻璃基片上制备了FeSiB/Cu/FeSiB多层膜,在100kHz-40MHz范围内研究了FeSiB/Cu/FeSiB多层膜中的巨磁阻抗效应特性。当磁场强度Ha施加在薄膜的长方向时,巨磁阻抗效应随磁场的增加而增加,在某一磁场下达到最大值,然后随磁场的增加而下降到负的巨磁阻抗效应。在频率为3.2MHz时,在磁场强度Ha=2400A/m时巨磁阻抗变化率达到最大值13.50%;在磁场强度Ha=9600A/m时,巨磁阻抗变化率为-9.20%。巨磁阻抗效应的最大值及负的巨磁阻抗效应与多层膜中磁各向异性轴的取向及发散有关。另外,当磁场施加在薄膜的短方向时,薄膜表现出负的巨磁阻抗效应,在频率为3.2MHz,磁场强度Ha=9600A/m时,巨磁阻抗变化率可达-12.50%。  相似文献   

8.
软磁薄带巨磁阻抗效应的数值分析   总被引:1,自引:0,他引:1  
利用磁畴壁移动模型以纳米晶软磁合金Fe73.5Cu1Nb3Si13.5B9为例对软磁薄带中的巨磁阻抗效应进行了数值分析,结果发现不同的磁导率机制并不能显著发迹巨巨磁阻抗效的大小仅由磁导率对外加磁场的敏感性决定,从趋肤深度的角度讨论了巨磁阻抗效应的频率特性。  相似文献   

9.
研究了不同温度热处理对Fe79.5P12C6Cu0.5Mo0.5Si1.5的巨磁阻抗的影响,发现GMI不仅与磁导率有关,而且也受到磁各向异性的作用。  相似文献   

10.
库万军  王新颜 《功能材料》1997,28(5):552-554
研究了不同温度热处理对Fe79.5P12C6Cu0.5Mo0.5Si1.5的巨磁阻抗的影响,发现GMI不仅与磁导率有关,而且也受到磁各向异性的作用。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
14.
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……  相似文献   

15.
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.  相似文献   

16.
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.……  相似文献   

17.
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.  相似文献   

18.
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.……  相似文献   

19.
We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.  相似文献   

20.
Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.  相似文献   

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