共查询到20条相似文献,搜索用时 46 毫秒
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无机类富勒烯纳米粒子具有良好的润滑性能.宏量制备高纯度的样品以满足性能测试的要求,是目前面临的主要技术难题.本文采用剥离-掺杂-水热处理这一工艺流程制备了多元金属二硫化物纳米粒子,应用XRD、TEM、HRTEM和EDS等分析手段对其形貌、晶相组成、结构和化学组成进行了表征.实验结果表明,多元金属二硫化物纳米颗粒具有管状形貌,管壁为多层状结构,化学组成为NiX(WYMo1-Y)1-XS2,同时,样品中具有类富勒烯结构的纳米粒子大幅度提高;并依据实验结果对多元金属二硫化物纳米管的形成机理进行了探讨. 相似文献
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无机类富勒烯纳米粒子具有良好的润滑性能.宏量制备高纯度的样品以满足性能测试的要求,是目前面临的主要技术难题.本文采用剥离-掺杂-水热处理这一工艺流程制备了多元金属二硫化物纳米粒子,应用XRD、TEM、HRTEM和EDS等分析手段对其形貌、晶相组成、结构和化学组成进行了表征.实验结果表明,多元金属二硫化物纳米颗粒具有管状形貌,管壁为多层状结构,化学组成为NiX(WYMo1-Y)1-XS2,同时,样品中具有类富勒烯结构的纳米粒子大幅度提高;并依据实验结果对多元金属二硫化物纳米管的形成机理进行了探讨. 相似文献
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电致变色纳米氧化镍薄膜的溶胶-凝胶法制备与表征 总被引:3,自引:0,他引:3
以无水氯化镍、乙醇为前驱液,加入适量的丁醇和柠檬酸为稳定剂,通过回流、水解得到稳定的溶胶;采用浸渍一提拉的方法在ITO导电玻璃上形成均匀的膜层;分析了溶胶制备中加水量的影响;研究了热处理温度对制备膜层的结构、光透过率的影响;对经过不同处理的膜层进行X射线衍射、透射电子显微镜、扫描电子显微镜、热重分析等研究表明:在空气中加热到350℃、保温30min薄膜分解为稳定的具有立方结构的NiO纳米晶;以氢氧化钾水溶液为电解质的循环伏安、电致变色实验结果表明制备的纳米氧化镍薄膜具有良好的电致变色特性. 相似文献
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SHI J WANG Z M BAO K PEROZ C BELOTTI M XU L P LUO C X SUN M H ZHANG B JI H OUYANG Q CHEN Y 《纳米技术与精密工程》2006,4(3):225-229
紫外光固化纳米压印是实现纳米结构批量复制的一种新技术.其特点是低成本和高分辨,而且可以达到极高的套刻精度.为了得到大面积图案的均匀复制,可用聚二甲基硅氧烷(PDMS)制备透光的压印软模板.其母版图案可由高分辨率电子柬曝光和反应离子刻蚀的方法在硅片基底上获得,然后用浇注的方法将图案转移到PDMS上.本实验特别发展了紫外光固化纳米压印适用于软膜压印的双层膜图型转移技术.该双层膜由廉价的光胶和聚甲基丙烯酸甲脂(PMMA)构成.对光胶层的压印可用普通的光学曝光仪实现.然后再将图案用反应离子刻蚀的方法转移到PMMA层中.为了证明方案的可行性,在两种不同材料的半导体基片上压印了三角晶格的光子晶体和准晶结构的图案,并用剥离的方法将它们转移到金属薄膜上,最后成功地进行了硅片刻蚀实验.相信这一纳米制做方法对大面积纳米光子结构和光学集成芯片的制造是普遍适用的. 相似文献
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碳热还原法制备SnO2纳米带及其表征分析 总被引:1,自引:0,他引:1
将高纯SnO2粉和石墨粉以一定的比例混合,放入陶瓷舟中,再将陶瓷舟放入一管式加热炉中加热至1100℃,在流动的高纯氩气中保温2.5h,制得白色絮状物.X射线衍射(XRD)分析表明,所制备的样品为具有正方金红石结构的SnO2.扫描电子显微镜(SEM)和透射电子显微镜(TEM)分析表明,所制备的样品为尺寸均匀一致的纳米带.选区电子衍射(SAED)结果证实所制备的SnO2纳米带为单晶.通过对其生长过程及机理分析可知,SnO2纳米带的生长是由气-固(VS)生长机制来控制的. 相似文献
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采用直流电弧等离子体法,在甲烷和氢气混合气氛下蒸发块体钛,制备出碳包覆碳化钛(C@TiC)壳/核型纳米结构粒子,利用x射线衍射仪、拉曼光谱仪和透射电子显微镜进行了物相、结构及形貌表征,结果表明,所制备的纳米粒子为碳包覆碳化钛结构,其碳包覆层厚度约1nm,部分纳米粒子呈现规则的六棱形貌。利用涂层法将碳包覆碳化钛纳米粉体制成电极,并通过循环伏安测试及电化学降解2,4-二氯酚实验,研究了碳包覆碳化钛纳米粒子的电化学性能及有机物降解性能。在一定负压范围内,碳包覆碳化钛纳米材料电极的降解效率随着负向电压的增大而增大;当电压为-1.0v时,其降解速率为8.55mg/(L·h);当电压为-0.5v时,降解速率为7.57mg/(L·h)。 相似文献
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MMT/SiO2复合载体制备聚乙烯纳米复合材料的探索研究 总被引:1,自引:0,他引:1
制备了柱撑结构蒙脱石(MM T)/S iO2复合载体,MM T层间距达3.3 nm,载体比表面积≥720 m2/g。将M gC l2/T iC l4/THF负载于此载体上制备聚乙烯催化剂,活性为30 g~40 g产品/g催化剂,填充量为2.5%~3.0%,此活性的纳米复合材料是一种添加剂,可满足填充聚合物使用要求。以TEM、XRD、DSC等技术研究复合材料结构性能关系及MM T对其结晶熔融行为的影响。结果表明,MM T片层以剥离型和插层型纳米尺度共存,片层均匀分散于聚乙烯中,所得纳米复合材料力学性能比普通复合材料有所提高。 相似文献
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《International journal for numerical methods in engineering》2018,113(9):1488-1506
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
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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
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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
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Standards are the basis for production enterprises to organize production ex-factory inspection trade 《中国标准化(英文版)》2008,25(1):24-25
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
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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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C. Qihong W. Zhan‐Wen J. Yi J. Yehua L. Fei F. Hanguang 《Materialwissenschaft und Werkstofftechnik》2014,45(7):582-590
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. 相似文献
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Dimiter Hadjistamov 《材料科学与工程:中英文B版...》2019,(2):56-65
The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ... 相似文献
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Kyo-Hong CHOI Kwon-Koo CHO Gyu-Bong CHO Hyo-Jun AHN Ki-Won KIM Yoo-Young KIM 《材料科学与工程学报》2007,25(6):886-891
Several researches have been reported about the characteristic of β-Ga2O3 nanowires which was synthesized on nickel oxide particle. But indeed, recent researches about synthesis of β-Ga2O3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst. In this work, Gallium oxide (β-Ga2O3 ) nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700 - 1000℃ using the iron, nickel, copper, cobalt and zinc oxide as a catalyst, respectively. The β-Ga2O3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850, 900 and 950℃ in all the catalysts. But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst. As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods, and its diameter increased. From these results, we could be proposed that the growth mechanism of β-Ga2O3 nanowires was changed with synthesis temperature of nanowires. Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM, FE-SEM, EDX and XRD. 相似文献
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Steffen Müller-Probandt 《材料科学与工程:中英文B版...》2018,(4):161-177
We associate a variety of innovations with the term "Industry 4.0". The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di... 相似文献