从二氰二胺的DMF溶液中电化学沉积氮化碳薄膜

首次采用二氰二胺的N,N二甲基甲酰胺(DMF)溶液做沉积液,用Si(100)和ITO导电玻璃做基底,在阴极上电化学沉积了CNx薄膜。X射线衍射(XRD)花样说明沉积的CNx薄膜为非晶结构。X射线光电子能谱(XPS)、傅立叶转换红外光谱(FTIR)分析结果表明CNx样品薄膜的N/C比为0.7左右,碳和氮主要以C—N、C=N的形式成键,有少量的碳和氮以C≡N的形式成键。电阻率测试显示,样品具有较高的电阻率,Si(100)和ITO导电玻璃基底上氮化碳薄膜的电阻率值范围分别为1011～1012Ω·cm和1012～1013Ω·cm。用Si(100)、ITO导电玻璃两种衬底,CNx薄膜的沉积速率、N含量和电阻率不同,说明衬底的选择对沉积过程和沉积膜的性能有重要影响。     

CNx薄膜的制备和光电性能

以单晶硅片(100)和镀Pt硅片为衬底,用电化学沉积方法在阴极制备出CNx薄膜(x接近于1),薄膜的表面平滑,颗粒均匀.热处理后得到了β-C3N4和α-C3N4多晶结构薄膜.热处理温度的提高使薄膜中的C≡N键逐渐减少而消失,氮元素的流失使薄膜中非晶碳的成分增多,但是薄膜中碳氮逐渐以sp3C-N为主.薄膜的能带在1.1～1.8 eV之间,氮含量对能带大小影响较大.热处理使薄膜的电阻率(高于108Ω@cm)变化不大.氮含量影响PL谱中3.0和3.5 eV处发射峰的峰强,不影响峰位.     

电化学制备CNx薄膜及其结构表征

在甲醇-尿素有机溶液中,采用电化学沉积方法,在单晶硅表面沉积得到掺氮的类金刚石薄膜.利用原子力显微镜、拉曼光谱、X射线光电子能谱、傅立叶分光红外光度计、X射线衍射仪研究了其表面形貌和微观结构.结果表明:电化学沉积得到的薄膜表面致密,但粗糙度较大;Raman光谱中出现明显的D峰和G峰,说明薄膜中存在无定形结构的碳基质;薄膜的化学元素组成主要为C,还有少量的N,C、N之间主要以单键和双键形式相连;薄膜中存在着一定数量的β-C3N4晶相.     

磁控溅射法制备CNx薄膜及其结构表征

以Ar/N2混合气体作为溅射气体,利用直流磁控溅射的方法制备子碳氮薄膜.利用X射线衍射和红外光谱对碳氮薄膜进行了结构分析.IR光谱证实了薄膜中碳氮化合物的形成,而XRD的检测结果表明,类石墨相g-C3N4是碳氮薄膜中的主要成分,同时有极少量的β-C3N4晶相生成.同时发现,Ar/N2溅射气体的分压对获取β-CsN4有着明显的影响.本实验中,当N2体积分数为33%,碳氮薄膜中β-C3N4晶相的含量最高.     

电化学沉积CNx薄膜的摩擦性能研究

以单晶硅片(100)为衬底,尿素-甲醇有机溶液为沉积液,用电化学沉积的方法在阴极制备出CNx薄膜.通过AFM、XPS、Raman光谱和FTIR光谱对得到的CNx薄膜的表面形貌和微观结构进行了表征,并在球-盘摩擦试验机上考察了薄膜的干摩擦性能,用SEM和EDS对摩擦表面进行了分析,研究了摩擦机理.结果表明薄膜表面致密,但粗糙度较大;Raman光谱中出现明显的D峰和G峰,说明薄膜具有无定形的结构特征;薄膜的化学元素组成主要为C,还有少量的N,C、N原子之间主要以共价单键和双键形式结合.CNx薄膜与红宝石球对摩时,摩擦系数随频率的增大而升高,但几乎不随载荷而变化;CNx薄膜在形成转移膜的过程中不仅失去了N,而且发生了石墨化,这与DLC膜的摩擦过程非常相似.     

真空阴极电弧沉积碳氮膜的研究

以氮气为反应气体，用真空阴极电弧沉积法沉积了CNx膜，并利用金相显微镜，Auger电子谱仪，FTIR及XRD对其进了分析，结果表明，真空阴极电弧沉积法可以制备含N量高，具有C＝N键和C－N键并含有晶态C3N4的CNx膜。     

离子束辅助脉冲激光沉积硼碳氮薄膜

以烧结B4C为靶材料、在氮离子束辅助下用脉冲激光沉积方法制备了三元化合物硼碳氮（BCN）薄膜.用X光电子谱和傅立叶变换红外谱方法表征了制备的薄膜.结果表明,膜层中包含B-C、N-C、B-N键等复合结构,以B-C-N原子杂化的形式结合成键,而并非各种成分的简单混合.还探讨了成膜过程和相关机理,离子束中的活性氮有效地和脉冲激光对B4C靶烧蚀产生的硼和碳结合成键,氮离子束的辅助还能在一定程度上抑制氧杂质进入膜层,给衬底适当加温有利于提高氮的含量并影响薄膜的化学结构.     

真空阴极电弧沉积碳氮膜的研究

以氮气为反应气体,用真空阴极电弧沉积法沉积了CNx膜,并利用金相显微镜、Auger电子谱仪、FTIR及XRD对其进了分析.结果表明真空阴极电弧沉积法可以制备含N量高、具有C≡N键和C-N键并含有晶态C3N4的CNx膜.     

磁控溅射掺碳TiB2薄膜的Raman光谱与摩擦行为

采用磁控溅射技术,使用SiC薄膜和Ti膜作为中间层在Cr12MoV钢表面制备掺碳TiB2(TiB2-C)薄膜,研究掺碳TiB2薄膜的Raman光谱、纳米压痕和摩擦行为。结果表明:溅射功率过高或过低都不利于掺入的C元素在薄膜中以DLC形式存在;C元素掺杂降低了TiB2薄膜的纳米硬度和弹性模量;以DLC形式存在的掺入的C能有效降低室温干摩擦(Si3N4球对摩件)条件下TiB2薄膜的摩擦因数。     

掺碳TiB2薄膜/钢摩擦副的干摩擦磨损性能

采用室温磁控溅射技术成功地在钢(Cr12MoV)基材表面制备出TiB2/SiC双层薄膜及掺碳TiB2(TiB2-C)/SiC双层薄膜,SiC薄膜为中间层。研究了掺碳对TiB2薄膜组织结构和摩擦磨损性能的影响。结果表明:SiC薄膜与基材和TiB2,TiB2-C薄膜间都具有明显且呈梯度的元素扩散;掺入的C以sp3C-C和sp2C-C形式存在,即以类金刚石形式存在;与钢球(直径为4 mm)对摩、干摩擦条件下,TiB2薄膜和TiB2-C薄膜的磨损速率在105mm3/(m.N)级,掺C明显降低了薄膜的摩擦系数(从0.82降低到0.45,5 min)和对对摩件(钢)的元素转移。分析表明,摩擦磨损性能的提高主要是TiB2-C薄膜中的C起到了固体润滑作用所致。     

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.