共查询到20条相似文献,搜索用时 750 毫秒
1.
大规模制备Ni纳米线阵列及其磁学特性研究 总被引:1,自引:0,他引:1
在多孔氧化铝模板的纳米孔洞中,利用直流电化学沉积的方法成功地制备了高度有序的磁性金属Ni纳米线阵列.利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)和物理性质测量系统(PPMS)对样品的形貌、晶体结构和磁学性能进行了表征测试.SEM和TEM观察结果显示,Ni纳米线均匀地生长在氧化铝模板的孔洞中,直径约为300nm,其表面非常光滑.XRD结果显示,生长的Ni纳米线为fcc结构.磁测量结果表明,与体材料相比,Ni纳米线展现出增强的矫顽力和剩磁比,并且表现出较强的磁各向异性,其居里温度约为627K,与块体Ni的居里温度相当,说明在较高温度下,纳米线仍可呈现铁磁特性. 相似文献
2.
3.
在氧化铝模板的纳米孔洞中,用电化学的方法沉积钴铁合金纳米线,经过550℃、30h氧化处理,成功制备出钴铁氧体纳米线阵列.分别用透射电子显微镜(TEM)、X射线衍射仪(XRD)和振动样品磁场计(VSM)对样品的形貌、晶体结构和磁学性质进行了表征测试.TEM观察结果显示纳米线粗细均匀,直径约为70nm.XRD显示纳米线的物相结构为CoFe2O4;VSM测试结果表明,CoFe2O4纳米线阵列的磁滞回线矫顽力为1.190×105A/m,比氧化处理前的钴铁合金纳米线阵列有显著提高. 相似文献
4.
5.
6.
7.
使用电化学沉积方法,在有序的氧化铝模板(AAO)孔洞中制备了铁纳米线有序阵列.用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)、对样品的结构、形貌、进行表征和观测.XRD的结果表明所制备的样品为纯的立方面心铁.SEM的图片清晰地说明铁纳米线阵列是大面积、高填充率和高度有序的.TEM的结果显示纳米线直径均匀、表面光滑且长径比大.磁测量的结果表明纳米线阵列的易磁化轴是垂直于模板表面的。 相似文献
8.
9.
在SOI基上制备光电纳米器件具有良好的光电集成应用前景,通过铜膜生长法在SOI基上制备了形貌为类针状的Cu(OH)2前驱体纳米线,并采用热处理法600℃条件下成功制备了CuO纳米线。通过扫描电镜(SEM)、透射电镜(TEM)、X射线衍射测试(XRD)对样品结构、形貌进行了表征。SEM、TEM测试结果表明,Cu(OH)2前驱体纳米线结构一致,尺寸均匀,表面光滑。在Cu(OH)2前驱体纳米线上二次生长的CuO纳米线具有类蒲草状细长光滑的结构,CuO纳米线直径约为80~100nm,长度约为10μm,CuO纳米线结晶性良好。 相似文献
10.
11.
《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
12.
13.
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
14.
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
15.
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
16.
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
17.
Janet Lang 《Materials and Manufacturing Processes》2017,32(7-8):857-866
ABSTRACTThe production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them. 相似文献
18.
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. 相似文献
19.
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
20.
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