氮离子注入法合成CNx膜的化学键表征

采用N离子注入金刚石膜和热解石墨方法合成了CNx膜,用Raman光谱和XPS谱对合成薄膜中C、N的化学键合状态进行了研究.通过与Raman光谱的比较,我们对合成样品XPS谱中N1s的化学键合状态作出如下归属:≈400.0 eV属于sp2 C-N键;≈398.5 eV则属于sp3 C-N键.结果显示:碳原子、氮原子间的化学键合状态,明显地依赖于衬底材料及注入N离子的能量.     

氮离子注入法合成CNx膜的化学键表征

采用N离子注入金刚石膜和热解石墨方法合成了CNx膜,用Raman光谱和XPS谱对合成薄膜中C、N的化学键合状态进行了研究.通过与Raman光谱的比较,我们对合成样品XPS谱中N1s的化学键合状态作出如下归属≈400.0 eV属于sp2 C-N键;≈398.5 eV则属于sp3 C-N键.结果显示碳原子、氮原子间的化学键合状态,明显地依赖于衬底材料及注入N离子的能量.     

基片温度对脉冲激光沉积CNx薄膜的组织结构和摩擦学性能的影响

采用脉冲激光烧蚀氮化碳薄膜靶,在室温至450℃基片温度下制备了CNx薄膜.利用扫描电镜、X射线衍射仪、X射线光电子谱仪和拉曼光谱仪等对薄膜的形貌、结晶性和结合键状态进行了表征.采用球-盘式摩擦仪测试了薄膜在大气中(相对湿度60％～62％)的摩擦磨损性能.结果表明:所得CNx薄膜均呈非晶状态,表面形貌与基片温度无关.随着基片温度的升高,薄膜含氮量由原子分数25.3％下降至21.2％,膜中sp3C-C键的含量增加且在300℃时达到最高,N-sp3C键的含量下降且在150℃时最高;拉曼谱中ID/IG比值上升,G峰蓝移且半高宽下降,薄膜结构有序度升高-石墨化程度增加;薄膜的摩擦系数从0.23下降至0.13,磨损率从3.0× 10-15 m3N-1m-1上升至9.3×10-15 m3N-1m-1.     

氟化非晶碳膜结构的Raman和FTIR研究

利用反应射频磁控溅射法,以单晶Si片为衬底,在不同功率下制备了氟化非晶碳膜样品,并进行了不同温度的退火处理。采用拉曼光谱、傅里叶变换红外光谱和原子力显微镜对样品的结构进行了表征。通过谱线Lorentzian分峰拟合方法,分析比较了不同功率下制备的氟化非晶碳膜sp杂化结构,得到了薄膜生长过程功率控制与结构的关系,功率增大、退火温度升高,膜内sp2相对含量增加。退火温度达到350℃时,薄膜中石墨结构明显增加。     

退火温度对DLC膜热稳定性及摩擦学性能的影响

采用非平衡磁控溅射技术分别在氮化硅陶瓷球和高速工具钢圆盘表面制备了类金刚石(DLC)膜。使用箱式电阻炉对DLC膜在大气环境中进行高温退火处理以研究环境温度对DLC膜摩擦学性能的影响;并分别采用激光拉曼光谱仪和球-盘式摩擦磨损试验机对退火处理前后DLC膜的结构和摩擦学性能进行了研究。采用金相显微镜观察了摩擦副磨损表面的形貌。研究发现,随着退火温度的升高,DLC膜中sp3杂化键向sp2杂化键的转化加快,当退火温度为600℃时,DLC膜发生严重的石墨化。而当退火温度为400℃时,DLC膜的摩擦系数及磨损率最小。拉曼测试表明400℃退火处理后DLC膜表层含有Si及SiO2,在摩擦过程中形成了含SiC的转移膜,使得DLC膜的摩擦系数明显降低,磨损减小。研究结果表明,退火处理对DLC膜的热稳定性和摩擦学性能有重要的影响。     

非晶金刚石薄膜对温度的敏感性研究

采用过滤阴极真空电弧技术制备非晶金刚石薄膜, 在-190～600℃范围研究非晶金刚石薄膜的温度敏感性. 利用液氮泵在Linkam试验台上冷却样品并实时采样, 通过炉中退火实现样品加热. 分别测试可见光拉曼光谱和纳米压痕, 研究薄膜的微结构和机械性能的变化. 实验表明: 过滤阴极真空电弧制备的非晶金刚石薄膜具有较好的热稳定性. 在空气中退火到400℃, 其硬度和弹性模量基本保持不变, 其结构可以一直稳定到500℃, 但是到600℃, 薄膜因为氧化作用而快速消耗. 非晶金刚石薄膜的可见光拉曼光谱显示随着温度的升高, 谱峰峰位向高频偏移. 在低温冷却过程中, 薄膜对温度变化不敏感, 其结构保持不变.     

FCVA法沉积的超薄类金刚石薄膜的结构与热稳定性

采用FCVA方法沉积了厚度分别为2nm、5nm、10nm和30nm的类金刚石薄膜.在氩气保护下对类金刚石薄膜进行了180、300、400和600℃,保温6h的退火处理.用Raman光谱和宽光谱变角度椭偏仪研究了DLC薄膜的结构和热稳定性.实验结果表明,随着薄膜厚度增大,FCVA法沉积的DLC薄膜中的sp3键含量增加,薄膜热稳定性逐渐改善.当DLC薄膜的厚度为30nm时,薄膜中的sp3键含量达到最高值,薄膜具有最好的热稳定性.当退火温度为600℃时,厚度为2nm和5nm的DLC薄膜结构由非晶态转变为微晶态;厚度为10nm和30nm的DLC薄膜结构发生转变但仍保持非晶态.随着退火温度的升高,各个厚度的DLC薄膜的光学带隙Eg均先增大后减小.     

溅射辅助微波等离子体化学气相沉积SiCN晶体

在微波等离子体化学气相沉积系统中,利用脉冲氮离子束溅射二氰二氨靶产生的碳氮粒子作为合成前驱物,在石英玻璃基片上研究了SiCN晶体的合成。用扫描电子显微镜(SEM)、X射线能谱(EDX)、X射线衍射(XRD)和X射线光电子能谱(XPS)研究了基片温度对薄膜的形貌、成分和结构的影响。结果表明:随着基片温度的降低,沉积物由截面为六方形的结晶良好的SiCN晶体(800℃)变成发育不完全的聚片状晶体(700℃),直到变成颗粒细小的无定形碳氮薄膜(550℃)。衍射峰的强度以及晶胞参数a和c的值随温度的降低而减小。薄膜为C原子部分取代Si3N4中的Si原子位置而形成的SiCN晶体,其中N原子主要与Si原子结合,C原子以sp3C—N、sp2CN和sp2CC键的形式存在。降低基片温度有利于提高薄膜中的C含量和sp3C—N键的含量。     

高温退火对反应溅射制备的a-SiC:H薄膜结构的影响

通过红外透射谱、拉曼散射谱和X射线衍射谱的测量,研究了反应溅射制备的氢化非晶硅碳膜（SP-a-SiC：H）高温退人处理后的结构变化。发现在等时退火的情况下,退火温度对薄膜结构影响明显,H原子的逸出温度与键合有关,H从CH_n中逸出要比从SiH_n键中追出需要更高的温度,样品经800℃退火后,a－SiC：H膜转化为μc－SiC膜     

C2H2流量对SiCN薄膜结构及阻挡性能的影响

采用C2H2和N2作为反应气体、多晶Si作为靶材,利用射频磁控溅射系统沉积了SiCN薄膜。利用傅里叶红外光谱仪、X射线衍射仪、四探针测试仪等研究了C2H2流量对薄膜结构、介电常数以及阻挡性能的影响。结果表明,薄膜为非晶结构,1000℃退火下未出现结晶,稳定性很好;随着C2H2流量的增大,薄膜表面颗粒呈现增大趋势;C原子取代Si原子占据薄膜中的网络位置,薄膜形成了以C-N键为主的网络结构;制得的SiCN薄膜介电常数在4.2~5.8之间,C,N含量以及薄膜结构是影响介电性能的关键因素,高温使得Cu穿过薄膜中的缺陷与Si发生互扩散是薄膜阻挡性能失效的主要原因。     

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.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

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.     

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.……     

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.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.