掺氮类金刚石薄膜的制备与性能研究

利用空心阴极放电在玻璃基底表面沉积掺氮类金刚石(DLc)薄膜.拉曼光谱(Raman)分析表明,所制备的碳膜具有典型的类金刚石结构.扫描电镜(SEM)和原子力显微镜(AFM)分析了薄膜表面形貌和粗糙度;利用摩擦磨损仪测量膜的摩擦磨损性能.结果表明,氮的掺入使得薄膜中颗粒致密平整,改变了薄膜的表面微观形貌,进而改善了薄膜的摩擦磨损性能.     

PECVD法制备类金刚石薄膜的摩擦学性能

采用射频等离子体增强化学气相沉积法(rf-PECVD),在45钢表面沉积了类金刚石(DLC)薄膜,借助激光拉曼光谱仪(Raman)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和原子力显微镜(AFM),分析了DLC膜的键结构、表面形貌和结构特征,用原位纳米力学测试系统测定了薄膜的硬度.以GCr15钢为摩擦副材料...     

常温生长类金刚石薄膜的实验研究

利用射频等离子体增强化学气相沉积(RFPECVD)工艺在常温下实现在不锈钢、硅片、玻璃等基底上大面积沉积类金刚石(DLC)膜.薄膜表面光滑致密,与衬底的结合力较高.用Raman,FTIR,SEM,EDX研究了薄膜的形貌、结构与组分.用栓-盘摩擦磨损试验机测试了薄膜的摩擦系数.通过优化沉积参数,所沉积的DLC膜在与100Cr6钢球对磨时摩擦系数低于0.01.在摩擦过程中DLC膜的磨损机制借助SEM进行了研究.     

PECVD法沉积类金刚石膜的结构及其摩擦学性能

以C2H2为碳源,Ar气为辅助气体,利用射频等离子体化学气相沉积的方法在有机薄膜PET和载玻片上制备了类金刚石(diamond-like carbon,DLC)薄膜.通过红外光谱(FTIR)、拉曼光谱(Raman)分析了所制备DLC薄膜的结构;利用原子力显微镜(AFM)分析了薄膜的表面形貌;另外,还利用摩擦磨损仪对薄膜的机械性能进行了研究.实验得到:FTIR、Raman谱图分析发现碳氢膜主要由sp2和sp3杂化的碳氢化合物呈层状堆积而成,其组分与沉积参数密切相关;同时,sp2和sp3杂化比例影响所制备薄膜的致密性、均匀性和耐磨性能.     

基于RFPECVD方法不锈钢上沉积类金刚石薄膜的机械与摩擦特性

讨论用射频等离子体增强化学气相沉积(RFPECVD)工艺,在室温下实现在1Cr18Ni9Ti不锈钢基底上镀类金刚石(DLC)膜.为提高DLC膜的结合力,首先在不锈钢基底上沉积Ti/TiN/TiC功能梯度膜.借助所设计的界面过渡层,成功地在不锈钢基底上沉积了一定厚度的DLC膜.通过优化沉积参数,所沉积的DLC膜在与100Cr6钢球对磨时摩擦系数低于0.020.在摩擦过程中DLC膜的磨损机制借助SEM、Raman分析进行了研究.     

Ti/TiN/TiC/DLC固体膜润滑特性实验研究

提出一种新型复合固体润滑膜,并讨论了该复合膜的结构和作用机理.复合结构的基本组成是传统硬质涂层TiN和TiC的结合,最上面的固体润滑膜是用射频等离子体增强化学气相沉积（RFPECVD）方法沉积的类金刚石（DLC）膜.分别用紫外拉曼光谱仪和扫描电子显镜分析薄膜的显微结构和表面形貌,用摩擦磨损实验机测定薄膜的摩擦学特性.结果表明,所制备的薄膜为类金刚石膜,薄膜表面含有大量的类石墨的sp2,能有效的担负固体润滑膜的功能.摩擦过程中产生的转移层也有助于减摩功能的实现.     

射频辉光放电等离子体化学气相沉积类金刚石膜的性能研究

用自行设计的RF PCVD(射频辉光放电等离子体化学气相沉积 )设备沉积类金刚石膜 ,并对膜的力学、光学、化学性能进行了分析。表明用该设备制备的类金刚石膜具有显微硬度高、磨擦系数小、膜基结合力高、对红外有良好的增透性 ,并且耐磨耐蚀、化学稳定性好。     

用于微机电系统的类金刚石膜制备及表征

采用等离子体源离子注入和电子回旋共振-微波等离子体辅助化学气相沉积技术相结合的方法在Si衬底上制备出了性能良好的类金刚石膜.通过共聚焦Raman光谱验证了薄膜的类金刚石特性,用原子力显微镜、微摩擦计和扫描电镜等对薄膜的表面形貌、摩擦系数和耐磨损性能进行了表征和测量.结果表明,用离子注入法制备过渡层大大提高了DLC膜与衬底的结合强度,薄膜的表面比较光滑,粗糙度大约为0.198 nm,具有较低的摩擦系数(0.1～0.15),具有较好的耐磨损性能.     

类富勒烯碳基薄膜与Al_2O_3对偶球的摩擦学性能研究

以甲烷(CH4)为前躯体,采用等离子体增强化学气相沉积(PECVD)技术,在单晶硅n-100基底表面制备类富勒烯纳米结构类金刚石薄膜(FL-C∶H)。采用高分辨透射电镜(HRTEM)、拉曼光谱仪(LABRAM)和多功能X射线光电子能谱仪(XPS)对薄膜的结构进行表征;利用原位纳米力学测试系统、摩擦磨损试验机、三维轮廓仪和奥林巴斯STM6光学显微镜分析比较薄膜在不同摩擦时间阶段的摩擦行为及磨痕处硬度变化情况。实验结果表明,所制备的类金刚石薄膜具有类富勒烯纳米结构特征,在摩擦过程中并未发生石墨化,而是sp2键合结构减少,使得磨痕处的硬度随着摩擦时间的增加而增大。     

磁过滤直流真空阴极弧制备含铬类金刚石膜的结构及其性能研究

采用磁过滤直流真空阴极弧沉积技术在单晶硅片、载玻片、不锈钢片基体上制备了含铬类金刚石(Cr-DLC)膜.用光学显微镜、椭偏仪、分光光度计、X射线光电子能谱(XPS)、X射线衍射能谱(XRD)、Raman光谱、纳米硬度计、摩擦磨损仪、洛氏硬度计检测了薄膜的组分结构、光学、力学等相关特性.结果表明,硅片上的薄膜厚度为47.6nm,碳含量为89%,s p~3键占碳含量的55.15%.不锈钢片上的薄膜具有典型的DLC膜Raman光谱特征,在空气中的摩擦系数约为0.1,耐磨性能优良,膜与基体的结合性能良好.     

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.     

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.     

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 ...     

Effect of Oxide Assisted Metal Nanoparticles on Microstructure and Morphology of Gallium oxide Nanowires

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.     

The Influence of Nitrogen and Boron Implant into Silicon Substrate on the Phase and Internal Stress of c-BN Films

Cubic boron nitride(c-BN) film was deposited on a Si (100) substrate by the RF-magnetron sputtering.The mainly problems for fabrication of c-BN films are the low purity and high intrinsic compressive stress. In order to solve the two problems, the c-BN film with the buffer interlayer was deposited on the substrate which had been implanted with nitrogen and/or boron ions. The results show: the implantation of nitrogen ions can obviously increase c-BN content and reduce the internal stress slightly; while the implantation of boron shows no obvious improvement to the content of c-BN, which can reduce the internal stress in the film obviously. In addition, it is suggested that the implantation of nitrogen and boron shows the best result, which not only can increase the content of c-BN, but also reduce the internal stress in the c-BN film obviously.