Au-Ag系统的扩散系数及其扩散激活能的研究

在银基底上蒸镀80nm的金薄膜,然后用不同温度和时间间隔对这些样品进行热处理。再用PHI 550型俄歇电子能谱仪测出上述样品金膜中银的浓度剖面分布。根据银的浓度剖面分布及Hall公式算出Au-Ag系统的互扩散系数。由Leclaire公式计算出该系统的晶界扩散系数。从Arrhenius方程得出互扩散及晶界扩散激活能。并对实验和计算结果进行了讨论。     

Optical, structural and surface characterization of CdO:Mg films

In this work, we have tried to improve some physical properties of CdO films by Mg doping. Ultrasonic spray pyrolysis technique has been used to obtain the films. Thicknesses and refractive indices of the films have been determined by Spectroscopic ellipsometry technique using Cauchy-Urbach model for fitting. Transmission and reflectance spectra have been taken by UV Spectrophotometer, and band gap values have been determined by optical method. X-ray diffraction patterns have been used to study the structural properties. Texture coefficient, grain size and lattice constants have also been determined. AFM images have been taken to see the effect of Mg doping on surface topography and roughness of CdO films. Finally, it has been concluded that Mg doped CdO films (especially at 4%) have improved properties and are good candidates for photovoltaic applications.     

Diamond polycrystalline composite material and its properties

The results of experimental studies on the development of a diamond polycrystalline material to equip drill bits have been considered. Angles of wetting graphite by sintering aids Ni, Co, and alloy of them have been defined. Among the composites, which have been tested, the longest durability and the highest strength have been exhibited by the composite of the Cd-Co-34Ni formulation.     

1.7MeV电子束在VO2热致相变薄膜中引起的结构和光电性能的变化

利用能量为1.7MeV,注量分别为10^13-10^15/cm^2的电子辐照VO2薄膜,采用XPS,XRD等测试手段对电子辐射前后的样品进行分析,并采用光透射性能和电光性能测试研究了电子辐照对样品相变过程中光电性能的影响,结果表明电子辐照在VO2薄膜中出现变价效应,产生新的X射线衍射峰,带来薄膜化学成分的变化,电子辐照在样品中产生的这些变化对VO2的热致相变特性有明显影响。     

层间引发聚合法制备EA/α-ZrP光固化纳米复合材料及其结构表征

以4-溴甲基二苯甲酮与二甲基正十二胺反应合成的新型长链季铵盐光引发剂苯甲酰苄基二甲氨基十二烷基溴化铵(BDDB),进行插层修饰α-ZrP,通过层间引发聚合的方法光固化制备EA/α-ZrP纳米复合材料.XRD和TEM分析结果表明,α-ZrP片层在光固化复合材料中已得到插层和部分剥离;力学性能测试结果表明,EA/α-ZrP光固化纳米材料的拉伸强度、弹性模量及断裂伸长率得到了显著提高.     

Stress-intensity factors for a cruciform crack with equal arm in an infinite elastic strip of finite thickness

The stress-intensity factors and the crack energy for a cruciform crack with equal arm, in an infinite elastic strip of finite thickness have been determined by solving the corresponding boundary value problem by using the Fourier Transform technique. The dual integral equations generated by using the necessary boundary conditions have been reduced to solving a pair of integral equations of Fredholm type involving two unknown functions. The integral equations have been solved by a numerical technique and the formulae for determining the quantities of physical interest have been expressed in terms of the solutions of the integral equations. Numerical results for these physical quantities have been furnished at the end for different values of the thickness of the strip.     

具有球形胞体结构的泡沫塑料弹性常数的确定

通过微分法导出了泡沫塑料剪切模量和体积模量所满足的微分方程组，并利用泡沫塑料各向同性弹性常数间满足的关系求解；得到了泡沫塑料剪切模量与体积模量的关系，确定了剪切模量与材料孔隙比的关系；并且将本文结果同其他已有模型了对比。     

Modelling of neutron survey instrument performance and experimental validation of those calculated response data

Three moderator-type neutron survey instruments have been modelled for energy and angle dependence of the response, in greater detail than before. These response data have been verified by comparison with published experimental measurements and measurements made specifically for this project. Influences on the instrument response have also been investigated. These have included its mode-of-use and perturbations caused by variations in the instrument manufacture. The implications of these new response data have been assessed by an extensive programme of folding the responses with workplace energy distributions.     

Synthesis of the hybrid porous rods and nanosheets composed of the nickel ions and poly(p-phenylenediamine) in aqueous solution

A new kind of metal-organic hybrid materials composed of the nickel ions and poly(p-phenylenediamine) have been synthesized in aqueous solution. Long hybrid rods and large nanosheets have been obtained by using the different ratios of the initial reactants. The synthesized rods and nanosheets have been characterized by SEM, TEM, AFM and XPS. The synthesized rods have been found to have porous polymeric structures. The nanosheets are made up of many small nanoparticles.     

搅拌球磨制备亚微米晶粒Ti(C,N)基金属陶瓷

用搅拌球磨方法制备了亚微米TiC-TiN-WC-Mo-Ni-C金属陶瓷复合粉，并烧结成亚微米晶粒Ti(C,N）基金属陶瓷；研究了原始粉末粒度，磨球大小，球磨时间对复合粉粒度的影响，研究了球磨过程中氧和铁元素对粉末的污染情况；并对烧结合金的组织，性能进行了分析，表明亚微米晶粒Ti(C,N）金属陶瓷的性能优良。     

Electron microscopy of layered single crystals grown by direct vapour transport method

Besides interesting properties such as optical, transport, structure, etc. possessed by crystals of transition metal dichalcogenides, they have also been found to have a potential application in the fabrication ofpec solar cells. These crystals are normally grown by carrier gas transport technique but are always contaminated by carrier gases. A new method of direct vapour transport has been developed and successfully applied to grow these crystals including those of off-stoichiometric varieties. The crystals thus grown have been characterized structurally using the techniques of x-ray powder, rotation and Weissenberg photographs and electron diffraction. Perfection studies have been made by techniques like chemical etching and electron microscopy. This review describes the electron microscopic studies made on the single crystals of the layered compounds. High resolution technique of weak beam has been employed to study dislocation pattern. Dissociated dislocations have been used to estimate stacking fault energy. Such measurements have also been carried out at different temperatures and the variation of stacking fault energy with temperature has been worked out. Interesting information regarding phase transformation for TaS₂ and W₃Se₄ in the temperature range 109 to 580 K has been derived from the electron diffraction studies and the implications have been discussed.     

A ceramic based on partially stabilized zirconia: Synthesis,structure, and properties under dynamic load

A ceramic based on zirconia partially stabilized by yttrium oxide has been prepared. The main properties of the prepared ceramic have been characterized: density, ultimate strength under twisting, microhardness, elasticity coefficients, etc. The microstructure and phase composition of the ceramic and its phase transformations under mechanical action have been studied. The properties of the ceramics under dynamic load have been studied, and the values of the dynamic elastic limit and splitting strength have been obtained. The results have been compared with the literature data.     

Electrical properties of ZnO/Au/ZnS/Au films deposited by ultrasonic spray pyrolysis

Polycrystalline ZnS semiconducting films have been prepared by ultrasonic spray pyrolysis technique in the form of planar and sandwich configurations using amorphous and ZnO coated glass substrates. Deposition of ZnS films by the spray pyrolysis has been studied extensively by several investigators and the process parameters have been optimized to obtain films with good characteristics. However we report for the first time the preparation of ZnS films sandwiched between top and bottom electrodes on the transparent conducting ZnO films that have been produced by the spray pyrolysis technique. The produced ZnS films have been crystallized in a wurtzite structure. The electrical properties of the samples having planar and sandwich structures have been measured in dark at room temperature by applying the voltage values between 0.01 and 100 V.     

Simultaneous preconcentration and removal of iron, chromium, nickel with N,N'-etylenebis-(ethane sulfonamide) ligand on activated carbon in aqueous solution and determination by ICP-OES

In this study, Fe, Cr and Ni have been preconcentrated and removed by using N,N'-ethylenebis (ethane sulfonamide), (ESEN) ligand on activated carbon (AC) in aqueous solution. For this purpose, complexes between these metals and ligands have been investigated and used in preconcentration and removal studies. Factors which have affected adsorption of metals on activated carbon have been optimized. Adsorbed metals have been preconcentrated 10-fold and determined by ICP-OES. Interferences of Ca, Mg and K to this process have been investigated. The proposed method has been applied to the tap water and Ankara Creek water in order to Fe, Cr, and Ni remediation and preconcentration. Determination of metals by ICP-OES has been checked with standard reference material (NIST 1643e). The proposed method provides the recoveries of 87%, 108% and 106% for Fe, Cr and Ni, respectively, in preconcentration. It also provides the removal of Fe, Cr and Ni by 93%, 100% and 100% removal from waters, respectively.     

Superplastic Microforming of Zn-A122 Alloy Ribs

Research on microforming of fine-grained superplastic Zn-AI22 alloy was carried out in this paper by means of superplastic forming. With the selected material, microformability tests have been carried out with the specially developed evaluation method by using two kinds of stainless steel dies. With these dies, micro-extrusion tests have been carried out and the characteristics of microformability of the material have been clarified. Effects of processing parameters and die structure on forming have been analyzed. SEM and metallographic microscope have been used to analyze the formed specimens. Through analysis of flow lines of the formed specimen, behavior of material could be understood well.     

Study of Cymbal Piezoelectric Composite Transducer Based on Finite Element Analysis

A cymbal piezoelectric composite transducer (CPCT) has been developed in recent years, which converts small radial deformation into larger longitudinal deformation. In this paper, the finite element analysis (FEA) method is used to analyze the characters of CPCT, by which the optimized CPCT has been made. Firstly, the FEA theory of a CPCT has been described, and the two-dimensional FEA model of a CPCT has been established by ANSYS. Secondly, the simulation and analysis about the relationships between structural parameters and displacement have been carried out, by which the CPCT samples have been made with optimized structure parameters. Thirdly, using laser interferometry, voltage–displacement relationships of CPCT samples have been measured. Finally, the displacement hysteresis and the aging behavior of a CPCT have been analyzed.     

The role of alloying elements in the design of nickel-base superalloys

The constituents of nickel-base superalloys have been classified into solid solution formers, precipitate formers, carbide formers and surface stabilizers. The characteristics of solutes which would make them most suitable in each category have been specified and appropriate alloying elements have been identified. Nickel-base superalloys are hardened primarily by the precipitation of Ni₃X type compounds. The occurrence and crystallography of precipitation of various kinds of Ni₃X type precipitates have been considered. The role of substitution by alloying elements on mismatch and stability of phases has been discussed. The free electron model and the Engel-Brewer model have been applied for evaluating the stabilities of precipitates, and the role of the alloying elements in determining the stabilities of external and internal surfaces such as grain boundaries have been briefly outlined.     

Characterization of chemically sprayed CdO films on borate and phosphate glass substrates produced by melt-quenching technique

The properties of substrates used to deposit thin films are an important parameter in thin film production. Instead of using a commercial substrate, in this work, borate and phosphate glasses have been obtained by classic melt-quenching technique to be used as substrates for CdO films. Also, a microscope glass substrate has been used to compare the coating properties by other glass substrates. All films have been produced by Ultrasonic Spray Pyrolysis technique. The substrate temperature has been selected as 275 ± 5 °C. Thicknesses and some optical parameters such as refractive index and extinction coefficient have been determined by spectroscopic ellipsometry. Absorbance and transmittance spectra have been taken by UV/VIS spectrophotometer. Four-probe method has been used to determine the electrical resistivity values of the films. XRD investigations have shown that type of the substrate dramatically affects the characteristics of CdO films. CdO film deposited on phosphate glass substrate has the best structural quality. Atomic Force Microscope has been used to investigate the surface properties and roughness values of the films.     

Investigation of multilayer silicon structures with buried iron silicide nanocrystallites: growth, structure, and properties

The growth of nanosize islands of iron silicides on Si(100) substrates and epitaxial silicon overgrowth atop them have been studied by low energy electron diffraction and reflectance high energy electron diffraction methods. The near optimal formation conditions of iron silicide islands with high density and minimal sizes have been determined by using of atomic force microscopy. Multilayer (8-10) monolithic structures with buried iron silicide nanocrystallites have been grown after the definition of monocrystalline burying conditions of iron silicides nanocrystallites in silicon lattice. The structure of buried nanocrystallites has been studied in multilayer monolithic heterostructures by high resolution transmission electron microscopy. It was established that in multilayer samples the majority of nanocrystallites have beta-FeSi2 structure, but some of them have gamma-FeSi2 structure. It was observed an influence of additional annealing at 850 degrees C on the morphology and structure of nanocrystallites. By means of deep level transient spectroscopy data one and two trap levels have been observed in multilayer structures (without and with additional annealing, respectively). Photoluminescence spectra have been studied at 4.2 K and the causes of its absence from buried beta-FeSi, NC have been analyzed.     

Machines for static and sustained loading

Conclusions Testing machines for static loading have common characteristic features which are independent from machine purpose and design. Sheer machine properties can affect the test result. Some of these influence factors which are of special interest for the moment, have been mentioned and possibilities pointed out how to reduce or eliminate the influences. More details have been given on the influence of machine stiffness and its diminution by the controlled hydraulic machine, as well as on the influence of the load measuring device and the necessity of an inertialess load measurement for certain tests. New-style regulating devices and strain measuring instruments have been dealt with; the influence of the load application elements has been shown by the example of compression-, tension- and buckling-specimens, and clamping tools indicated which have been developed under consideration of the same. The problems have been illustrated by building material testing machines for compression and buckling tests, as well as tensile and universal testing machines. Creep and relaxation testers for tests at ambient temperature, under elevated temperature or in a vacuum, as well as for concrete testing, have been described in short.