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在磁性高分子材料的研究中,为了获得磁性能高、粒径小和稳定性好的纳米晶磁核,作者对CrxFe3-xO4纳米晶磁性载体的制备和性能作了研究。通过化学共沉淀法制得的CrxFe3-xO4纳米晶,具有20-30nm的粒径,比饱和磁化强度σs≥50emu/g,磁学性能Hc(矫顽力)近纯Fe3O4的3倍。 相似文献
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用频磁控溅射方法在不同基片温度下玻璃基片上分别制备NiO单层膜、NiFe单层膜和NiO/NiFe双层膜,研究了不同基片温度对膜的磁性能的影响,用振动样品磁强计(VSM)分析了膜的磁特性,结果表明:基片温度260℃时淀积的NiFe膜矫顽力HC为184A·m^-1,小于室温淀积NiFe膜的HC(584A·m^-1),且磁滞回线的矩形度更好,室温下淀积NiO(50nm)/NiFe(15nm)双层膜的HC 相似文献
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1 ABS塑料的表面金属化以化学法在塑料件表面上形成与基体有一定结合能力的金属层。步骤如下:(1)化学涂油 NaOH 40~50g/L;Na2CO3 15~20g/L;Na3PO4 15~20g/L;表面活性剂 3~5ml/L;温度 50~60℃;时间 15~20min。(2)化学粗化 CrO3 350~400g/L;H2SO4 380~400g/L;温度 50~60℃;时间 20~30min。(3)敏化、活化溶液 采用的胶体钯活化液,PaCl2 0.8~1.0g/L;SnCl2·2H2O 50… 相似文献
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采用一种简单的新工艺分别在硅片和氧化铝陶瓷基片上制备了r-Fe2O3薄膜。该工艺分3步完成:首先利用Fe(NO2)3酒精溶液通过浸渍涂布工艺制备a-Fe2O3薄膜,其次a-Fe2O3薄膜在氢气流中、320 ̄350℃之间热处理30min被还原为Fe3O4薄膜,最后Fe3O4薄膜在空气中250℃左右热处理30min被氧化为r-Fe2O3薄膜。XRD和SEM分析结果表明该r-Fe2O3薄膜呈尖晶石物相和 相似文献
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本文途述了化学法制备Co-Fe_3O_4磁流体的试验结果。在适宜的工作条件下,只要活性剂和载液选择得当,且与磁性颗粒之间的配比合理,就可以制备出磁性强和稳定性好的Co-Fe_3O_4磁流体。通过对主要操作变量参数的研究,确定了最佳工艺条件。对相同操作条件下制备的Co-Fe_3O_4磁流体和Fe_3O_4磁流体进行了比较,结果表明:前者的饱和磁化强度远大于后者。本试验研究为研制高质量的磁流体提供了依据。 相似文献
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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
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The end of over unit products of more than Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits beer wine yellow wine fruit syrup wine others cover over % of the national top-branded liquor products.…… 《中国标准化(英文版)》2008,25(1):30
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
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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
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N.A. Odintsova N.V. Ageenko K.V. Kiselev N.M. Sanina E.Y. Kostetsky 《International Journal of Refrigeration》2006,29(3):387
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
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David R. Smith F. R. Fickett 《Journal of research of the National Institute of Standards and Technology》1995,100(2):119-171
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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Fco. Javier Franco Pérez Marc Gener Moret 《Materials and Manufacturing Processes》2017,32(7-8):876-884
ABSTRACTThe production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials. 相似文献
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As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion. 相似文献
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Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting. 相似文献
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TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure. 相似文献
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R. Owsiński S. Kamiński M. Szymaniec A. Niesłony T. Łagoda 《Materialwissenschaft und Werkstofftechnik》2015,46(10):1059-1067
The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase. 相似文献