反应射频磁控溅射制备高k氧化锆薄膜及介电性能的研究

在氧气和氩气的混合气体中,在O2/Ar混和气总流量固定的条件下,通过调节O2/Ar流量比,采用反应RF磁控溅射法制备了具有高介电常数的氧化锆薄膜。通过透射电子显微镜(TEM)和原子力显微镜(AFM)研究了O2/Ar流量比与薄膜微观组织和结构、表面平整度之间的关系,并测试分析了在不同O2/Ar流量比下溅射沉积的Al/ZrO2/SiO2/n型Si叠层结构的C V特性曲线。实验结果表明O2/Ar流量比与薄膜微观组织和结构有一定的关系。纯氧气氛下沉积的ZrO2薄膜基本上为纳米级的微晶,晶体结构为单斜结构(a=5.17、b=5.26、c=5.3、α=γ=90°,β=80.17°),在O2/Ar流量比为1∶4混合气氛下制备出了具有非晶结构的均质ZrO2薄膜;低的O2/Ar流量比下溅射得到的ZrO2薄膜样片,均方根粗糙度较低,表面平整度较好;在O2/Ar流量比为1∶4左右时,ZrO2薄膜的相对介电常数达到25。     

动态离子束混合沉积氧化钽薄膜的微观分析

用动态离子束混合技术在铁基材料表面上制备氧化钽薄膜.用Ar 束溅射沉积薄膜的同时,分别用100 keV,2×1017/cm2的O 离子或100 keV,8×1016/cm2的Ar 进行辐照.对两种工艺下生成的氧化钽薄膜进行了XPS、AES及RBS分析研究,结果发现,Ar 辐照下制备的氧化物薄膜主要由符合化学剂量比的Ta2O5化合物组成,引入的碳污染少.O 辐照下制备的薄膜生成了低价的氧化钽,引入了大量的碳污染.     

正偏压作用下多弧离子镀ZrO2薄膜的组织结构与力学性能研究

在氧气和氩气的混合气体中,以O2/Ar流量比固定为1/4的条件,通过改变正偏压大小,采用多弧离子镀方法制备了新型高k栅介质——ZrO2薄膜。通过X射线衍射(XRD)和原子力显微镜(AFM)研究了在不同正偏压作用下正偏压值与薄膜的相结构、表面形貌之间的关系,利用纳米压痕仪测量了不同正偏压作用下沉积得到的ZrO2薄膜的硬度及弹性模量,并观察了ZrO2薄膜经不同温度退火处理后的相结构及表面形貌的变化。结果表明,在各个正偏压条件下,薄膜结构呈微晶或非晶;ZrO2薄膜的均方根粗糙度随着正偏压的升高而降低;正偏压为100V时硬度和弹性模量均达到最大值,分别为16.1GPa和210GPa。     

氧分压对RF磁控溅射ZrO2薄膜生长特性的影响

采用反应射频(RF)磁控溅射法在n型(100)单晶S基片上沉积了ZrO2膜,研究了氧分压与ZrO：薄膜的表面粗糙度和沉积速率、SiO2中间界层的厚度以及ZrO2薄膜的折射率之间关系。结果表明：随着氧分压增高,薄膜的沉积速率降低,表面粗糙度线性地增加;在低的氧分压情况下,Si基片表面的本征SiO2层的厚度增加幅度较小,在高的氧分压情况下,Si基片表面的本征SiO2层的厚度有较大幅度地增加;在O2／Ar混和气氛下,溅射沉积的ZrO2薄膜的折射率受氧分压的影响不显著,而在纯氧气气氛环境下,ZrO2薄膜的折射率明显偏低,薄膜的致密性变差。     

反应磁控溅射法制备F掺杂ZnO(FZO)薄膜的结构和透明导电性能

以Zn/ZnO/ZnF2混合物为靶材,在衬底温度(Ts)为150℃和300℃、溅射气氛为Ar+O2和Ar+H2下反应溅射制备F掺杂ZnO(FZO)薄膜,研究气体流量、Ts以及溅射气氛对薄膜结构及透明导电性能的影响.结果表明:对于Ar+O2下制备的FZO薄膜,Ts=300℃时有利于制备出具有(002)择优取向、结晶度高、压应力低且透明导电性能较好的薄膜.对于Ar+H2下制备的薄膜,Ts增大到300℃虽然提高了薄膜结晶度和透光性,降低了压应力,但薄膜厚度明显降低,薄膜导电性能变差.比较两种气氛下制备的FZO薄膜,发现Ar+H2下制备的薄膜可在150℃和0.8～3.2 mL·min-1的H2流量范围内得到更好的透明导电性能(电阻率为3.5×10-3Ω·cm,可见光平均透光率为87％).讨论Ar+H2气氛时H等离子的刻蚀作用与H掺杂、A r+O 2气氛时O离子的轰击作用与薄膜氧缺陷的变化、Ts升高时沉积原子反应活性与迁移能力增强以及Eg与载流子浓度的关系.     

射频磁控溅射室温下制备ITO薄膜的光学性能研究

靶材为铟锡氧化物(In2O3:SnO2=1:1),用射频磁控溅射法在低温下制备了光电性能优良的ITO薄膜.质量流量计调节Ar气压强为0.2～3.0Pa,氧流量为0～10sccm,并详细探讨了溅射时氩气压强和氧流量变化对ITO薄膜光学性能的影响.结果表明:溅射Ar气压强为0.8Pa,氧流量为2.4sccm时,薄膜的折射率最低n=1.97,较接近增透膜的光学匹配.薄膜厚度为241.5nm时,薄膜的最大透过率为89.4%(包括玻璃基体),方阻为75.9Ω/□,电导率为8.8×10-4Ω·cm.     

RF磁控溅射制备Al_2O_3薄膜及其介电性能研究

以-αAl2O3为靶材,采用射频磁控溅射法制备了非晶Al2O3薄膜。利用X射线衍射仪、扫描电镜、划痕仪、表面粗糙轮廓仪和阻抗仪研究了不同溅射功率和不同溅射气压对薄膜制备的影响,探索了不同溅射功率下制备的Al2O3薄膜的介电常数和介电损耗与频率的关系。试验结果表明,制备的非晶Al2O3薄膜表面平滑致密;随着工作气压的增加,薄膜沉积速率增加;随着溅射功率的增加,Al2O3薄膜的沉积速率和介电常数逐渐增加、介电损耗逐渐减小;随着频率的增加,Al2O3薄膜的介电常数逐渐减小,高频阶段趋于稳定。     

溅射工艺参数对Ba0.5Sr0.5TiO3薄膜沉积速率和介电性能的影响

铁电/介电BST(BaxSr1-xTiO3)薄膜在微电子学、集成光学和光电子学等新技术领域有广泛的应用前景.用射频磁控溅射方法制备了厚约700 nm的Ba0.5Sr0.5TiO3薄膜,采用Al/BST/ITO结构研究了溅射功率、溅射气压、O2/(Ar O2)比和基片温度对上述BST薄膜沉积速率和介电性能的影响,并根据这些结果分析了较优的工艺条件,同时用XRD、XPS和SEM研究了薄膜的晶相、组成和显微结构.     

O2/Ar气体流量比对射频磁控溅射HfO2薄膜的影响

采用射频磁控溅射法,以HfO2陶瓷作为靶材,在石英衬底上制备了HfO2薄膜.通过椭圆偏振光谱仪(SE)、X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)研究了不同O2/Ar气体流量比对薄膜沉积速率、结构、形貌等的影响.结果表明,随着O2/Ar气体流量比从0增加到0.50,薄膜的沉积速率逐渐下降.O2/Ar气体...     

射频磁控溅射沉积高质量ZnO薄膜的工艺研究

在室温下利用射频磁控溅射法在硅(100)基片上制备ZnO薄膜,利用X射线衍射(XRD)和扫描电子显微镜(SEM)对其结晶性能进行分析。研究了制备条件对薄膜沉积速率的影响。分析了薄膜沉积速率对薄膜结晶状况的影响及源气体中的氧气和氩气的流量比对薄膜结晶状况的影响。研究结果表明,薄膜的生长速率强烈依赖于射频功率和工作气压,薄膜的结晶性能强烈依赖于薄膜的沉积速率和反应气体中氧气和氩气的流量比。制备高结晶质量的ZnO薄膜的最佳工艺参数为靶到衬底的距离为4cm,输入功率为250W,源气体中氩气和氧气的流量比n(Ar)∶n(O2)为5∶20,溅射工作气压为2Pa。在最佳工艺条件下所制备的薄膜表面平整致密,接近单晶,在可见光区的透射率高达90%。     

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.……     

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...     

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.     

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 ...