新型工艺制备ZnO薄膜的结构与形貌研究

采用了一种新型工艺制备ZnO薄膜。新工艺采用二步法,首先在N型Si(100)衬底上用离子束沉积溅射一层金属Zn膜,然后通过热氧化金属Zn膜制备ZnO薄膜。通过X射线衍射、原子力显微镜对不同制备工艺下的ZnO薄膜进行结构与形貌的分析比较。研究表明,Zn膜的离子束溅射沉积时间、热氧化时间和辅助枪的离子束对热氧化后的ZnO薄膜再轰击处理对ZnO薄膜的结构与形貌都会产生影响。     

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。     

Cu薄膜上热氧化法制备CuAl_2O_4薄膜

采用离子束辅助沉积方法在95%(质量比)Al_2O_3基板上制备Cu薄膜,利用热氧化法使Cu薄膜氧化,并与Al_2O_3基板反应,制备出CuAl_2O_4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CuAl_2O_4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Al_2O_3基板开始反应形成CuAl_2O_4晶体。当热氧化温度为1100℃时反应更加完全,形成纯度较高的CuAl_2O_4薄膜,且薄膜晶粒尺寸明显增大,薄膜表面Al元素含量增加。     

p型透明导电的锡镓氧化物薄膜的制备及其表征

本文通过磁控溅射锡镓合金靶(Ga/Sn=0.2)及热氧化的方法,成功地制备了p型透明导电的锡镓氧化物(TGO)薄膜.X射线衍射(XRD)测试结果表明,TGO薄膜保持SnO2的金红石结构.吸收谱测试表明TGO薄膜在可见光范围内透过率可达到85%以上,其光学禁带宽度Eg约3.8 eV.霍尔效应测试结果表明,TGO薄膜的载流子类型及其浓度与热处理温度密切相关.热氧化温度过高或过低均不利于空穴浓度.当热氧化温度处于(600～700) ℃之间时,可以获得p型透明导电的TGO薄膜,最高空穴浓度高达8.84×1018 cm-3.     

热氧化法制备纳米ZnO薄膜及其发光特性的研究

用热氧化ZnS薄膜方法制备纳米ZnO薄膜．并用X射线衍射谱．光致发光谱表征和研究纳米ZnO薄膜结构特征及热氧化温度对薄膜质量的影响。X射线衍射结果表明纳米ZnO薄膜具有六角纤锌矿结构．且随热氧化温度升高．薄膜晶粒尺寸逐渐增大。光致发光谱是由紫外激子发光和与氧空位有关的深能级缺陷发光组成的．且随热氧化温度升高，激子发光峰发生红移．激子发光和深能级缺陷发光强度之比逐渐增大．在热氧化温度为800℃时，其比值为10。     

低电压驱动微流控芯片二氧化硅绝缘薄膜的研究

采用电子束蒸发法在玻璃基底上制备了二氧化硅薄膜,利用原子力显微镜(AFM)、台阶仪、X射线衍射仪(XRD),分别对不同条件下制备的二氧化硅薄膜的表面形貌、膜厚、结构进行了表征,并采用金属/绝缘膜/金属(MIM)结构对薄膜的I-V电学特性进行了分析。结果表明玻璃基底温度在300℃条件下生长的4μm厚度的二氧化硅薄膜,其表面均匀平整,耐压能力>200V,能够承受500kV/cm以上的场强,满足作为低电压驱动微流控芯片绝缘薄膜的要求,并在样品驱动的应用中得到验证。     

掺钨二氧化钒薄膜的制备与分析

通过凋研国内外的各种制备方法,比较它们的优缺点后,选用磁控溅射法.在硅片上得到了电阻变化2个数量级的二氧化钒(VO2)薄膜.对薄膜进行电学性能的测试,结果表明:掺钨后二氧化钒薄膜的相变温度比纯的二氧化钒薄膜相变温度有所降低,掺钨后薄膜的近红外透射率也随之减小.通过X射线衍射和X射线光电子谱对薄膜的微观结构和组分进行了分析.     

微波等离子体低温制备氮杂二氧化钒薄膜

选用V2O5为前驱物,通过在玻璃片上镀膜,采用微波等离子体增强法,在低温条件下,成功制备了氮杂二氧化钒薄膜.通过X射线衍射(XRD),FT-IR对样品进行表征,结果表明:合成的样品为多晶氮杂二氧化钒.相变温度测试结果表明:退火工艺可以降低相变温度,同时提高薄膜的结晶度;改变氮气流量,相变温度先降低后升高,当氮气流量为20ml/min时,相变温度可以降低至40℃.     

低温热氧化处理温度与时间对氧化钒薄膜性能的影响

采用直流对靶磁控溅射氧化钒薄膜再附加热氧化处理的方式进行金属-半导体相变特性氧化钒薄膜的制备,研究了低热处理温度下热处理温度与时间对氧化钒薄膜组分、晶体结构和相变性能的影响.新制备的氧化钒薄膜为V2O3和VO的混合相.经300℃/1h热处理后,薄膜内出现单斜结构VO2,薄膜具有相变特性;保持热处理时间不变,升高热处理温度至360℃,薄膜表面变得致密,致密的薄膜表面阻碍了氧气与薄膜内部V2O3和VO的反应,VO2成分含量与300℃/1h处理时的含量接近;增加热处理温度并延长热处理时间,如热处理条件为320℃/3h时,薄膜内VO2成分大量增多,电阻值变化幅度超过两个数量级;在300～360℃的热处理温度区间内,薄膜内V2O3和VO不断向VO2转变,相变性能变好,但对VO2的单斜金红石结构没有影响.     

通过氧化Cu膜制备Cu_2O薄膜

通过热蒸镀Cu膜并在空气中退火制备Cu2O薄膜,利用X射线衍射(XRD)、能量分散X射线谱(EDX)和原子力显微镜(AFM)研究了已沉积和不同温度退火薄膜的晶体结构、成份和表面形貌。结果表明,Cu膜在200℃退火30分钟可以得到具有单一成份的Cu2O薄膜。四探针测量得到所制备的Cu2O薄膜电阻率为0.22Ωcm。用紫外可见光分光光度计(UV-vis)研究了Cu2O薄膜的光学特性,得出其光学带隙为2.4eV。     

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.     

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.……     

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.     

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.