氩离子轰击和溅射功率对Cu薄膜结构及性能的影响

采用直流磁控溅射法在PI柔性衬底上制备Cu膜.通过接触角测试仪、X射线衍射仪、四探针测试仪等仪器研究了Ar+轰击时间和溅射功率对薄膜接触角、择优取向、晶粒大小及电阻率的影响.测试结果表明:随着Ar+轰击时间的延长,接触角减小,轰击时间为3 min时,接触角达到最小为45.0°,进一步延长Ar+轰击时间反而会导致接触角增大.Ar+轰击时间由1 min增加到3 min时,平均晶粒尺寸由16.6 nm增加到22.9 nm,电阻率从16.2 μΩ·cm降低到10.7 μΩ·cm.溅射功率从3250 W增加到7500 W时,(111)晶面择优取向增强,Cu膜平均晶粒尺寸由15.1nm增加到17.6nm,电阻率从11.6μΩ·cm降低到7.4μΩ·cm.     

PbS:Zn~(2+)纳米薄膜的化学水浴法制备研究

采用化学水浴法在抛光的p型Si(100)衬底上制备了本征Pb S及掺Zn的Pb S:Zn2+多晶纳米薄膜,采用X射线衍射谱、扫描电子显微镜、分光光度计和高阻仪着重研究了反应混合液中Zn2+的摩尔浓度(CZn)对薄膜微结构、近红外吸收特性及电学性质的影响。本征Pb S及Pb S:Zn2+薄膜均为多晶的立方结构且具有(200)择优取向;随着CZn的增大,(200)方向的平均晶粒尺寸(22~74 nm)基本上先减小后增大,表面颗粒的形状由起初的不规则趋于三角形和金字塔形。Pb S:Zn2+薄膜的吸收边随着CZn的增大先蓝移后红移,吸收边的蓝移归结于晶粒尺寸效应和(200)晶面上压应力的增大,而红移则归结于(200)晶面上晶粒尺寸的增大和压应力减小。随着CZn的增大,样品的电阻率先从1.31×105Ω·cm减小到1.0×102Ω·cm,然后再增大。这可能与纳米材料的量子局域效应和晶界处的微应变有关。     

掺硼对超纳米金刚石薄膜的影响

采用微波等离子体化学气相沉积(MPCVD)技术,利用氩气、甲烷、二氧化碳混合气体,制备出平均晶粒尺寸在7.480 nm左右,表面粗糙度在15.72 nm左右的高质量的超纳米金刚石薄膜;在此工艺基础上以硼烷作为掺杂气体,合成掺硼的金刚石薄膜.表征结果显示在一定的浓度范围内随着硼烷气体的通入,金刚石薄膜的晶粒尺寸及表面粗糙度增大、结晶性变好,不再具有超纳米金刚石膜的显微结构和表面形态;同时膜材的物相组成也发生改变,金刚石组份逐渐增多,并且膜层内出现了更明显的应力以及更好的导电性能.     

氧气流量对MPCVD法制备超纳米金刚石膜的影响

采用微波等离子化学气相沉积技术,以CH_4/H_2/Ar为气源,通过调节O_2流量,增强等离子体对非金刚石相的刻蚀能力,提高超纳米金刚石膜中金刚石相的含量。并利用扫描电子显微镜(SEM)、X射线衍射(XRD)、拉曼光谱及X射线光电子能谱(XPS)分别对超纳米金刚石膜的形貌、生长速率、晶型、晶粒尺寸及金刚石含量进行了表征分析,重点研究了O_2流量对晶粒尺寸及金刚石含量的影响。实验结果表明,随O_2流量的增加,平均晶粒尺寸从8.4nm增大至16.1nm,随后减小至9.6nm;当O_2流量为0.7sccm时,金刚石相含量由71.58%提升至85.46%,平均晶粒尺寸约为9.6nm。     

富氮N_2/CH_4/H_2体系中金刚石纳米线的制备研究

使用微波等离子体化学气相沉积(MPCVD)法在富氮N_2/CH_4/H_2体系中纳米金刚石膜沉积进行研究。使用扫描电子显微镜对纳米金刚石膜的表面形貌进行测试,使用光射线光电子能谱(XPS)和拉曼光谱对纳米金刚石膜的表面化学结构进行表征。结果表明,氮气浓度的改变对纳米金刚石膜的表面形貌和晶粒尺寸都有明显影响。在氮气浓度为85%时,纳米金刚石膜的表面由平均长度为2.5μm金刚石纳米线组成,晶粒尺寸在85%最低,为8 nm。纳米金刚石膜氮元素含量随氮气浓度上升而上升在95%为2.68%。晶粒尺寸下降,晶界含量上升,C=C键含量上升;晶粒尺寸上升,晶界含量下降,C=C含量下降。C-C键含量随着晶粒尺寸下降而下降,随晶粒尺寸上升而上升,同时C-C峰的FWHM值在氮气浓度为85%时最低为1.16 e V。     

超薄Au膜的微结构及电学特性

用直流磁控溅射在室温Si基片和载玻片上制备了厚度为7.6～81.3nm超薄Au膜,用X射线衍射及数字电桥对薄膜的微结构和电学性质进行了测试分析.微结构分析表明:制备的超薄Au膜仍为面心立方多晶结构;在膜厚d＜46.3nm时,(111)晶粒平均晶粒尺寸随膜厚增加逐渐增大,当d＞46.3nm后,晶粒尺寸几乎保持不变,甚至有所减小;(220)晶粒的平均晶粒尺寸则总是随膜厚的增加而增大.薄膜晶格常数均比PDF标准值(0.4078nm)稍小,随膜厚增加,薄膜晶格常数由0.4045nm增大到0.4077nm.电阻率分析结果表明,随着膜厚的增加,薄膜的电阻率经历了岛状膜的极大-网状膜的急剧减小-连续膜的缓慢减小.膜厚d＞46.3nm后,由于薄膜中长出新的(111)小晶粒,电阻率略有增加.     

热阴极DC-PCVD方法制备的金刚石厚膜的生长特性和内应力

采用热阴极DC PCVD(DirectCurrentPlasmaChemicalVaporDeposition)方法制备出大尺寸高质量的金刚石厚膜,研究了金刚石厚膜的生长特性和内应力状态。由热阴极DC PCVD方法制备的金刚石厚膜大多数为〈110〉取向,表面显露面主要是(100)面和(111)面,厚膜的表面被较多的孪晶所覆盖,部分(111)面退化为3个相互垂直的(110)面,孪晶使厚膜表面结晶特性复杂化,金刚石厚膜的晶粒沿生长方向呈现柱状生长。金刚石厚膜的生长速率随甲烷流量和工作气压的增加而增加,但随生长速率的提高金刚石膜的品质明显下降。金刚石厚膜的内应力以压应力为主,随着甲烷浓度的增加压应力增加,随着工作气压的增加压应力减小,到某个气压之后变为张应力。     

衬底温度对磁控溅射ZrN薄膜结构和物理性能的影响

采用直流反应磁控溅射法在Si(111)衬底上制备了ZrN薄膜,通过X射线衍射仪、拉曼光谱仪、场发射扫描电子显微镜、原子力显微镜以及霍尔测量等测试分析手段表征了薄膜的微观结构、表面形貌及电学性能。结果表明,制备的ZrN薄膜为立方相NaCl结构,具有(111)面择优取向。在T_s=550～650℃时,薄膜的结晶性最佳。薄膜呈柱状生长,晶粒尺寸会随着衬底温度的升高先增大后减小,当T_s=550～750℃时,表面出现三角锥状晶粒。制备的ZrN薄膜表面较为平整,表面粗糙度在3.9～6.67 nm之间。测得薄膜的电阻率大小在1.43～24.5×10~(-3)Ω·cm之间,且电阻率与薄膜的结晶性以及晶粒尺寸相关;薄膜的载流子浓度在0.869～4.38×10~(20) cm~(-3)之间,T_s=550～650℃的薄膜电学性能较好。     

近空间升华法制备CdZnTe厚膜及其性能研究

采用近空间升华法在FTO玻璃衬底上制备CdZnTe多晶厚膜,并采用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、紫外-可见光谱仪、I-V测试仪等对CdZnTe厚膜的表面形貌、成分、结构以及光电性能进行分析表征。结果表明,所制备的CdZnTe膜均匀致密,随生长时间的延长,晶粒尺寸明显增大;不同厚度的CdZnTe膜均表现出沿(111)晶面的择优生长;CdZnTe厚膜的禁带宽度在1.53～1.56eV之间;电阻率在1010Ω.cm数量级,具有较好的光电响应,试制的薄膜探测器可用作计数型探测器。     

基于电纺技术构筑多孔SnO2纳米纤维膜的研究

以聚乙烯吡咯烷酮(PVP)作为纺丝助剂,五水合四氯化锡(SnCl4·5H2O)作为前驱体,采用静电纺丝技术结合高温煅烧法成功制备了直径为(363±28)nm的多孔氧化锡纳米纤维膜.使用SEM表征了纤维膜的微观形貌和尺寸,利用X射线衍射仪(XRD)研究了焙烧温度对晶粒尺寸的影响,利用傅里叶变换红外光谱仪(FTIR)、热重和差热同步仪(TGA-DTA)及拉曼光谱仪(Raman)等研究了纤维膜的分子结构变化、热稳定性和物相结构.研究结果表明,固定两喷丝头间距15.0 cm、流速0.5 mL/h、电场强度1.1～1.4 kV/cm时,可以电纺出表面光滑、直径均一的纳米纤维膜;经900℃焙烧制备得到晶粒尺寸约12.27 nm的四方相金红石型晶体结构的氧化锡纤维膜.     

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.……     

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.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

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...     

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.……     

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.     

Roman iron and steel: A review

ABSTRACT

The 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.     

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

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 ...