离子束辅助沉积A12O3薄膜的微观状态及其物理特性研究

本利用透射电子显微镜、原子力显微镜、X光电子能谱等微观分析手段，系统研究了氧离子束辅助离子束沉积方法制备的Al2O3薄膜的化学成分、微观结构、表面形貌及其随退火温度的变化，并对Al2O3薄膜折射率、显微硬度和膜基结合强度等物理特性及其随沉积温度的变化进行了详细研究。研究发现：用离子束辅助沉积制备的薄膜基本满足Al2O3的标准成分配比；在沉积温度低于500℃制备的Al2O3薄膜以非晶Al2O3相a—Al2O3为主；Al2O3薄膜的表面粗糙度、折射率、显微硬度随沉积温度的增加而增加；当沉积温度高于200℃时，薄膜与基体间的膜基结合强度将随沉积温度的增加而下降。分析表明：薄膜表面形貌与晶体内部的结构相变有关，薄膜的退火相变途径为a—Al2O3800℃→γ-Al2O31000℃→γ-Al2O3 α-Al2O31200℃→α-Al2O3。     

多晶Al2O3薄膜的制备及其红外吸收谱研究

高能氢离子束溅射金属铝靶,沉积在单晶Si基片上的非晶薄膜是Al和Al2O3的混合物.在空气中对其进行900～1200℃的热处理,成功地制备了以不同结晶形式存在的多晶Al2 O3薄膜,讨论了不同退火温度对其结晶性能、表面形貌及红外吸收光谱的影响.为Al2O3薄膜制备与应用提供了良好借鉴.     

氧化钽薄膜表面形貌和光学性能的研究

本文采用电子束蒸发配以Kaufman离子源产生的氧离子辅助沉积了Ta2O5薄膜,用原子力显微镜（AFM）表征了薄膜的表面形貌、表面粗糙度,探讨了Ta2O5薄膜在此工艺下的表面质量.用分光光度计测试了不同厚度下薄膜的透射率,计算出了其折射率.实验及分析结果表明：所制备的Ta2O5薄膜表面平整度高,是弱吸收薄膜,随薄膜厚度的增加短波截止波长向长波方向略有漂移;折射率随膜厚的变化不大,此制备工艺的可重复性强,制备薄膜性能稳定;薄膜表面粗糙度随膜厚的增加而增加,但是增加不大,所制备Ta2O5薄膜是理想光学薄膜;离子束的加入,使得薄膜表明形貌变化更加复杂,打破了热蒸发制备薄膜的柱状生长模式.     

Cu薄膜上热氧化法制备CuAl2O4薄膜北大核心CSCD

采用离子束辅助沉积方法在95%(质量比)Al2O3基板上制备Cu薄膜,利用热氧化法使Cu薄膜氧化,并与Al2O3基板反应,制备出CuAl2O4薄膜。通过X射线衍射仪、扫描电子显微镜、能谱仪和X射线光电子能谱仪分别对CuAl2O4薄膜的结构、成分和微观形貌进行了表征。研究结果表明,大气环境下,热氧化温度低于1000℃时,薄膜主要成分为CuO,随着热氧化温度的提升,薄膜成分比例并无较大变化,但是薄膜晶粒在不断增大;热氧化温度为1000℃时,氧化后的Cu薄膜与Al2O3基板开始反应形成CuAl2O4晶体。当热氧化温度为1100℃时反应更加完全,形成纯度较高的CuAl2O4薄膜,且薄膜晶粒尺寸明显增大,薄膜表面Al元素含量增加。     

CLAM钢表面硬质薄膜的制备与性能研究

采用射频反应磁控溅射法在中国低活化马氏体(CLAM)不锈钢表面制备了单层Al2O3、SiC、W薄膜以及SiC/Al2O3、W/Al2O3双层膜.对所制备的薄膜进行了XRD结构分析、AFM表面形貌测试和显微硬度测试.结果表明:单层SiC薄膜表面出现了部分脱落,而SiC/AlO3双层膜表面完整光滑.W/Al2O3双层薄膜表面平整光滑,均方根粗糙度为4.28 Ha.W单层薄膜和W/Al2O3双层薄膜经氩气中800℃退火2 h后硬度最高,分别达到了34.4 GPa和31.3 GPa.     

退火温度对Si基Bi4Ti3O12铁电薄膜微观结构影响研究

采用Sol-Gel工艺制备了Si基Bi4Ti3O12铁电薄膜。研究了退火温度对Si基Bi4Ti3O12薄膜晶相结构、晶粒尺寸及薄膜表面形貌的影响。研究表明，退火温度低于450℃时Bi4Ti3O12薄膜为非晶状态，退火温度在550-850℃范围内均为多晶薄膜，而且随退火温度升高，Bi4Ti3O12薄膜更趋向于沿c轴取向的生长；而晶粒尺寸及薄膜粗糙度随退火温度升高而增大，但在较高温度下增长速度趋缓。     

射频磁控溅射法制备Al2(WO4)3薄膜和负热膨胀性能研究

采用WO3和Al2O3陶瓷靶材,以双靶交替射频磁控溅射法,在石英基片上沉积制备了Al2（WO4）3薄膜。利用X射线衍射仪（XRD）、扫描电子显微镜（SEM）,研究了退火温度对Al2（WO4）3薄膜的相组成和表面形貌的影响,采用表面粗糙轮廓仪和划痕仪测量薄膜厚度,探索了薄膜的制备工艺以及薄膜与基片的结合力,采用高温X射线衍射和晶胞参数指标化软件,初步研究了薄膜热膨胀特性。实验结果表明：磁控溅射沉积制备的这种薄膜为非晶态,表面平滑、致密,随着热处理温度的升高,薄膜开始结晶且膜层颗粒增大,在950℃热处理10min后得到Al2（WO4）3薄膜,薄膜与基片的结合力为13．6N,薄膜物质热膨胀特性呈各向异性。     

离子束辅助反应电子束蒸发TiO2薄膜的结构和光学性能

TiO2具有较高的折射率和介电常数,在光学和电子学方面有着广泛的应用。本论文采用离子束辅助反应电子束真空蒸镀法,以Ti为膜料,纯度为99．99％的O2为反应气体,通过电子束蒸发,在玻璃衬底上反应生成TiO2薄膜。使用XRD、SEM分别对50℃、150℃、300℃三个不同衬底温度下沉积的薄膜及其经过450℃真空退火1h后的结构进行了分析,对薄膜的折射率、透射率进行了测量。结果表明,与传统的电子束蒸发相比,离子束辅助电子束蒸发可以增加成膜原子的能量,使沉积的薄膜结构致密,所制备的薄膜具有较高的折射率,并且薄膜在可见光范围内具有良好的透过性能。     

奥氏体不锈钢表面硬质薄膜的制备与性能研究

用磁控溅射法在奥氏体不锈钢基片上分别制备了TiN薄膜和Al2O3薄膜,并用XRD、SEM和显微硬度等测试手段对沉积态和退火态薄膜进行表征,分析了不同工艺参数对薄膜的沉积速率、结构和性能的影响,从而得到最佳工艺参数。TiN薄膜在沉积气压为1．5Pa,氩氮比为16：16时薄膜的硬度值最大为16．0GPa。Al2O3薄膜在沉积气压为0．5Pa,氩氧比为10：1时薄膜的硬度值可达25．2GPa。     

氧离子能量对离子束辅助沉积Al2O3薄膜的结构及光学性能的影响

利用氧离子束辅助脉冲反应磁控溅射技术在聚酰亚胺基底上沉积Al2O3薄膜。这项技术在溅射高纯铝靶材的同时利用低能氧离子进行氧化来控制薄膜的化学配比。研究了薄膜沉积过程中离子束辅助的作用以及离子束放电电压对Al2O3薄膜的化学成分、结构、表面形貌、光学性能以及沉积速率的影响。结果发现,离子束放电电压对薄膜的化学成分具有显著影响,当电压增加到200 V,薄膜已基本达到完全化学计量比且薄膜为非晶结构;薄膜表面粗糙度随着离子束放电电压的增加而减小,当电压达到300V时,薄膜具有最小的表面粗糙度;通过对Al2O3薄膜透射谱的测量,分析薄膜的光学特性,获得了薄膜的光学常数随离子束放电电压的变化规律,发现氧离子束辅助沉积的薄膜具有较高的折射系数和较低的消光系数;另外,薄膜的沉积速率在电压增加到300V时达到最大值70 nm/min,是未采用离子束辅助时沉积速率的5倍。     

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.     

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...     

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.     

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.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

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.……     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.