bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Expansion of Copper and Nickel Sulfides and their Alloys
Authors: Selivanov Evgeny N. , Nechvoglod O.V. , Gulyaeva R.I.
Published: March 2013

Thermal expansion coefficients of metal sulfides and their alloys are important for technological processes calculations of sulfide processing materials, for example, the crystallization equipment of nickel and copper-nickel converter matte. The synthesized copper and nickel monosulfide, and nickel and copper-nickel matte have been used as the initial samples. Dilatometric analysis was carried out by dilatometer (Linseis L78 RITA). Differences in the values measured are accounted for by the synthesis samples facilities, the coexistence of several non-stoichiometric sulfide phases and interaction during heating. In the temperature 20-500°C range the coefficients of thermal expansion (α) for the sulfides of copper, nickel and their alloys are changed from 10.4 to 20.610-6 1/K. Changes in the value α are accounted for by phase transitions in sulfide samples at their heating. Considering the properties of the phase components are an additive it is shown the thermal expansion coefficient complex sulfide-metal alloys is possible to calculate.
Secondary Oil Recovery by Water Injection: A Numerical Study
Authors: de Lima Cunha A. , de Farias Neto Severino Rodrigues , de Lima Antônio Gilson Barbosa , Barbosa E. Santos
Published: March 2013

In this work we carried out a numerical study of the heavy oil recovery process in oil reservoir through water injection. We performed transient tridimensional numerical simulations, considering an isothermal process, with a variation in the position of water injection section (interior and surface) in the reservoir, using the ANSYS CFX 11 commercial package and evaluated its effects on the recovery factor of oil. The numerical results showed that varying the flow rate of water injection from 0.10 to 0.25 kg/s there was an increase in the flow of water and oil produced in 193% and 28%, respectively, and the recovery factor in 16.7%
Calculation of Autocorrelation Functions Using the Dv-Xα Method for 14 Electron Diatomic Molecules
Authors: Kobayashi Kohjiro , Suzuki Kosuke , Sakurai Hiroshi
Published: March 2013

sotropic and directional autocorrelation functions are calculated for 14 electron diatomic molecules, N2, CO, and BF, using the DV-Xα method. In order to investigate the effect of chemical bonds for the molecules, directional autocorrelation functions parallel and perpendicular to the bond are investigated. The anisotropies of the directional autocorrelation functions of N2and CO are different from the anisotropy of BF, which has a wave shape.
A High Efficiency, Extended Load Range Boost Regulator Optimized Forenergy Harvesting Applications
Authors: Nosker Zachary , Kobori Yasunori , Kobayashi Haruo , Niitsu Kiichi , Takai Nobukazu , Oomori Takeshi , Odaguchi Takahiro , Nakanishi Isao , Nemoto Kenji , Matsuda Junichi
Published: March 2013

A small, low power bootstrapped boost regulator is introduced that can start upwith an input voltage of 240mV and achieve a maximum efficiency of 96%. The proposed circuituses two separate control schemes for startup and steady-state operation. A xed-frequencyoscillator is used to initially start up the circuit and raise the output voltage. Once the outputvoltage has reached a level adequate to bias the internal circuitry, a constant-on-time stylehysteretic control scheme is used, which helps increase system efficiency compared to using aconventional Pulse-Width-Modulated control scheme. While maintaining a high efficiency, theproposed circuit only requires 3 external components|2 capacitors (input and output) and aninductor. The e ectiveness of this approach is shown through Spectre simulation results.
Synthesis of MnZn-Ferrite Using Sintering Aids
Authors: Hoshi Kazushi , Kenmochi Haruki , Fukunaga Takayuki , Furusawa Shinichi , Sakurai Hiroshi
Published: March 2013

Mn0.7Zn0.3Fe2O4is synthesized by sintering the nanosize precursor with sintering aids, which is synthesized by the coprecipitation method. The crystal growth of Mn0.7Zn0.3Fe2O4is controlled by the amount of sintering aids. Complex permeability is explained by the Maxwell-Garnett (MG) effective medium model. The ferromagnetic resonance frequency more than 1 GHz can be explained by the shape anisotropy under the sintering process of the Mn0.7Zn0.3Fe2O4particles. These results suggest possibility of Mn0.7Zn0.3Fe2O4as a high frequency device material.
Velocity Filter Based Tissue Elasticity Imaging for Low Frequency Vibration Wave Method
Authors: Miwa Takashi , Yoshihara Yuki , Yamakoshi Yoshiki
Published: March 2013

An elasticity imaging method using continuous vibration wave excitation is expected to be a safe and quantitative technique. A velocity map is successfully produced by running wave number spectrum analysis of the 2D displacement map of the shear wave propagation. However, a problem is still remained that the accuracy and resolution is not sufficient for medical application. This paper presents an elasticity imaging method based on velocity filtering to clear the boundary of a hard target. We demonstrate an effectiveness of this method through the simulated data.
Electrical Properties of DC-Sputtered Amorphous InGaZnO4 Films
Authors: Kaneda Kenji , Gotoh Tamihiro
Published: March 2013

Electrical properties in dc-sputtered amorphous InGaZnO4films have been investigated using the thermopower and resistivity measurements. The amorphous InGaZnO4films shown-type conduction at room temperature, and electrical activation energy of ~0.47 eV. The resistivity and Seebeck coefficient at room temperature were ~2×104Ωm and 1.5 mV/K for as-deposited sample. The resistivity and Seebeck coefficient decreased to ~2×100Ω·m and 2.7 mV/K when the sample was annealed at 670770 K. Slow response of photocurrent was also observed. Partial crystallization and structural change cause the improvement of electron transport with annealing treatments.
Structural Properties of SrTiO3 Transparent Thin Films Formed by RF Magnetron Sputtering with Changing Substrate Temperatures
Authors: Kakiage Kenji , Ishiuchi Shiho , Kyomen Toru , Hanaya Minoru
Published: March 2013

Transparent thin films of strontium titanate (SrTiO3) were formed on the substrate of quartz glass plate by RF magnetron sputtering with changing the substrate temperatures during the sputtering from 100 to 700 °C. The particle size and the lattice constant of the cubic-SrTiO3 crystallites composing the film were exhibited to be changed from 13 to 48 nm and from 4.02 to 3.96 Å, respectively, by the change of the substrate temperatures from 400 to 700 °C. The UV absorption edges of the transparent film samples shifted to longer wavelength with the increase of the particle size and the decrease of the lattice constant of the nanocrystalline SrTiO3.
Effect of Molecular Structure of Polyols with Different Molecular Characteristics on Synthesis of Boron Carbide Powder
Authors: Kakiage Masaki , Tahara Naoki , Tominaga Yusuke , Yanagidani Satomi , Yanase Ikuo , Kobayashi Hidehiko
Published: March 2013

Crystalline boron carbide (B4C) powder was synthesized by the carbothermal reduction of condensed products formed from boric acid (H3BO3) and polyols with different molecular characteristics, i.e., glycerin, mannitol, and poly (vinyl alcohol) (PVA). The effect of the molecular structure of the polyol on the thermal decomposition conditions and the obtained morphology of the B4C powder was discussed in this study. The thermal decomposition in air of each condensed product was performed before the carbothermal reduction in order to eliminate the excess carbon, where the decomposition conditions varied with the type of polyol. Crystalline B4C powder with less residual free carbon was synthesized from the thermally decomposed products by heating at 1250 °C for 5 h in an Ar flow. The thermal decomposition conditions and the particle size of the obtained B4C powder reflected the molecular characteristics of the polyols.
A Constitutive Model for Shape Memory Alloys Involving Transformation, Reorientation and Plasticity
Authors: Peng Xiang He , Chen Min Mei , Wang Jun
Published: March 2013

A constitutive model is developed for shape memory alloys (SMAs) based on the concept that an SMA is a mixture composed of austenite and martensite. The deformation of the martensite is separated into elastic, thermal, reorientation and plastic parts, and that of the austenite is separated into elastic, thermal and plastic parts. The volume fraction of each phase is determined with the modified Tanaka’s transformation rule. The typical constitutive behavior of some SMAs, including pseudoelasticity, shape memory effect, plastic deformation as well as its effects, is analyzed.
The Effect of Specimen Size on the Dynamic Compressive Behaviour of Magnesium Alloy AZ31B
Authors: Xiao Jing , Shu Dong Wei
Published: March 2013

The specimen size has always been crucial in defining the materials behaviour and becomes more important when materials are subjected to high rates of loadings. In the current study, the effect of specimen size on the mechanical behaviour of AZ31B alloy has been investigated under dynamic compression using the Split Hopkinson Pressure Bar (SHPB) and results are presented. Specimens were made in different sizes with fixed slenderness ratio (l/d) of 0.5 and with bar to specimen diameter ratio varying between 0.47 and 0.79. When deformed at the same strain rate 1500±50s-1, the smaller specimens give higher stresses and smaller strains. The smaller size specimens give more uniform strain rate as compared to the larger size specimens. However, some spurious oscillations are observed in the stress-strain curves for smaller size specimens. The alloy shows higher hardening behavior for larger size specimen; the hardening exponent n is larger for larger size specimens.
An Influence of Step Cyclic Loading due to Torsion on Tensile Curve Variation
Authors: Kowalewski Zbigniew L. , Szymczak Tadeusz
Published: March 2013

The paper presents experimental results of tests carried out at room temperature on power engineering steel: 10H2M (11CrMo9-10) using thin-walled tubular specimens under biaxial stress state. The loading programme comprised different types of deformation, i.e. monotonic tension and cyclic torsion in the form of symmetric or asymmetric step-increasing strain amplitude. The main task of the paper was focused on investigation of an influence of the cyclic loading parameters on tensile curve variations. The magnitudes of axial strain and cyclic shear strain amplitude were small and did not exceed 1%. An analysis of the results showed a significant reduction of the axial stress (even equal 90% for the torsional amplitude ±0.8%, in both cases of cyclic loading). An influence of torsion frequency on the tensile stress curve was discovered within the range from 0.005Hz to 0.5Hz.
Viscosity of Amorphous Materials during Glass-Forming: More from the Adam-Gibbs Law
Authors: Ruan H.H. , Zhang Liang Chi
Published: March 2013

This study aims to investigate the microscopic origin of viscosity by simplifying an amorphous system to a mixture of many independent atomic subsystems. The response of the macroscopic system is then taken as an ensemble average of the relaxations of such subsystems. The result shows that with the reduction of temperature, the overall viscosity changes from the harmonic mean of the subsystems, which is dominated by the fast relaxations, to the arithmetic mean governed by the slowest relaxation. The successful application of our model to the amorphous Selenium indicates the model captures the fundamental mechanism of the viscosity variation.
Closure Behavior of Longitudinal Cavities in a Slab by Side Pressing
Authors: Park Jong Jin
Published: March 2013

Longitudinal cavities or pipes are usually developed in a metallic slab or billet produced by continuous casting. In the present study, closure behavior of such cavities by side pressing was investigated by finite-element method. Since the contact surface between the dies and the slab was much longer in the longitudinal direction than in the thickness direction, the slab was compressed under the condition of plane-strain deformation. As a result, the effective strain was found to be an indicator for the void closure. The critical value of the effective strain was dependent upon the aspect ratio of the cross section of the cavity, but not upon its size.
Effect of Heat Treatment Conditions on Tube Hydroforming Characteristics of Aluminum Alloy
Authors: Lee Myeong Han , Shin Young Chul , Yoon Duk Jae
Published: March 2013

Tube hydroforming is a metal forming technology that utilizes internal pressure and axial compressive loads to generate designed product shapes with complex sections from tubular materials. The tube hydroforming process has been used in the automotive, aircraft, and bicycle industries for many years. With the pursuit of lighter bicycles, aluminum alloys have been utilized as an alternative to steel. To obtain adequate strength, the aluminum alloys should undergo heat treatment processes before being used. However, the mechanical properties of the alloys vary with the tempering conditions. This paper aims to evaluate the effects of tube hydroforming characteristics on different kinds of tempered aluminum alloys. Based on numerical simulations, suitable tube hydroforming processing conditions for each tempered aluminum alloy are suggested.
NC-Form Grinding of Carbon Fibre Reinforced Silicon Carbide Composite
Authors: Uhlmann E. , Borsoi Klein T. , Schweitzer L. , Neubrand A.
Published: March 2013

This paper presents an approach for the development and optimization of the NC-form grinding technology for an efficient machining of carbon fibre reinforced silicon carbide composite (C/SiC). The C/SiC properties, the importance and the necessity of the application of a high performance grinding process for the machining of this innovative composite material are introduced first. Then, the methodologies and the experimental investigations of NC-form grinding with the application of several machining parameters and three distinct bond types (vitrified, metal and synthetic resin) of diamond mounted points for the abrasive machining of C/SiC are presented. In order to monitor and analyze the process, grinding forces, surface integrity of ground workpieces and grinding wheel wear are investigated. The results of this paper provide new information regarding the wear behavior of grinding tools and the optimized conditions for grinding of C/SiC
Study on Heading and Thread-Rolling Processes of Magnesium Alloy Screws
Authors: Hwang Yeong-Maw , Hwang Kai Neng , Chang Chia Yu
Published: March 2013

This study is to investigate the effects of the process parameters on the heading load and metal flow pattern during heading and thread-rolling processes of LZ91 magnesium alloy screws. A heading process composed of two stages is proposed. The material flow pattern of the billet inside the die is analyzed using the finite element analyses. The effects of the upper die velocity, temperatures and friction factors on the heading loads and product quality are discussed. On the other hand, in the thread-rolling process, the effects of the friction factor on the effective stress, effective strain, and tooth height are investigated. Finally, heading and thread-rolling experiments are conducted using a self-designed die set and a lubricant of MoS2. The experimental values are compared with the simulation results to verify the validity of the finite element models and the proposed heading procedures.
Temperature and Processability of Magnesium Alloy AZ31 on Rectangular Cup Deep Drawing
Authors: Nakayama Yasuhide , Naka Tetsuo , Uemori Takeshi , Shimizu Ichiro
Published: March 2013

The magnesium alloys, that have high specific strength, are often applied to the industrial products. However, the magnesium alloys exhibit low ductility at the room temperature on account of its hexagonal close-packed structure. It is difficult to give large deformation to the magnesium alloys at room temperature. Therefore, the plastic forming of a magnesium alloy sheet needs the process at warm temperature. In the present work, the procedure of thermal-mechanical coupled analyses are employed. The numerical simulations of warm deep drawings have been performed in order to evaluate the dependence of the temperature on the plastic forming of a magnesium alloy AZ31 sheet. The mechanical properties of the magnesium alloy AZ31 shall be described as the functions depending on temperature. The shapes of punches and die holes are rectangle whose aspect ratios are 1.5 or 2.0. The corners of punches and dies are heated locally at 473K. The influence of local heating on the formability have been investigated. The relation between the blank size and the formability has been also estimated. As the results of numerical simulations, it was shown that the formability of deep drawing was improved by local heating to the punch and the die. When the blanks of various sizes were tried, the distributions of the plastic strain rate around the die corner were changed. Therefore, the deviation of the plastic flow and the temperature distribution arose in a sheet. Consequently, it is necessary to optimize the blank sizes according to the shape of die holes in addition to the forming temperature.
Experimental Approach for Investigation of Micro Void Behavior on Dual Phase Steel during Plastic Deformation
Authors: Ishikawa Takashi , Ishiguro T. , Yukawa N. , Yoshida H. , Fujita N.
Published: March 2013

In this research, micro void behavior of DPS, which has different phase volume fraction, is investigated experimentally. Prepared specimens have different amount of alloy element and heat treatment condition. Although both these specimens have almost the same strength and total elongation, these showed quite different local elongations, hole expanding ratio and bending ductility. In order to observe micro void behavior specimens, that have different strain levels, are prepared. These sectional areas are observed by laser microscope after cutting and polishing. The change ratio of micro void volume fraction of DPS, which showed high local ductility, is lower than that of the other DPS. Concerning low ductility DPS, small size void (less than 3µm diameter) increases rapidly not only at grain boundary but in the ferrite grain, especially at initial stage of deformation. On the other hand, nucleation of micro void of high ductility DPS is inhibited.
Quasi-Static Crush Behavior of Aluminum Hexagonal Honeycomb with Perforated Cell Walls
Authors: Wang Zheng Jin , Qin Qing Hua , Wang Fang Fang , Zhang Jian Xun , Wang Tie Jun
Published: March 2013

The crush behavior of aluminum hexagonal honeycomb with perforated cell walls under out-of-plane quasi-static loadings was experimentally investigated. The honeycomb specimens with different heights were compressed in axial direction under displacement control. There are four sequential deformation stages during compression: linear elasticity, buckling, crushing and densification state. The performances of hexagonal honeycombs with perforated cell walls were compared with those of imperforated hexagonal honeycombs with the same sizes. The results show that the perforated holes weaken the strength of honeycombs markedly and the strength of honeycomb decreases with the specimen height.
An Experimental Evaluation on Change in Impedance of TRIP Steel Subjected to Plastic Deformation at Various Strain Rates
Authors: Inoshita Daiki , Yamanaka Shiro , Iwamoto Takeshi
Published: March 2013

For automotive industries, weight of an automobile can be reduced if TRIP steel which has excellent mechanical properties dominated by strain-induced martensitic transformation (SIMT) can be applied to shock absorption members. However, strain rate sensitivity of TRIP steels has not been fully understood because a relationship between a strain rate and an amount of martensite produced by SIMT is still unclear. In previous studies, volume resistivity and impedance have been measured to obtain information on the amount of produced martensite, however, these studies have not been succeeded to clarify the relationship. Here, by focusing a property that martensite shows ferromagnetism, it is attempted that impedance of TRIP steel is measured at various strain rates during the deformation by using prototype coil and circuits.
Cooling Tower Shell under Asynchronous Kinematic Excitation Using Concrete Damaged Plasticity Model
Authors: Dulinska Joanna M.
Published: March 2013

The paper presents the analysis of the dynamic response of a cooling tower to moderate earthquake. To represent inelastic behavior of the concrete material of the tower under dynamic loading, the concrete damaged plasticity constitutive model was assumed. The model consists of the combination of non-associated multi-hardening plasticity and scalar damaged elasticity to describe the irreversible damage that occurs during the fracturing process. Two different models of seismic excitation were used. Initially, a classical model of uniform kinematic excitation was applied. In this model it was assumed that excitation at all supports was identical. Then, a model of non-uniform kinematic excitation, typical for large multiple-support structures, was introduced. In that model the wave passage along the foundation ring was taken into account. It occurred that the assumption of asynchronous excitation led to the increase of the dynamic response of the tower with respect to the assumption of uniform ground motion. The tensile damage (cracking) in some parts of the tower appeared and the stiffness of the concrete was degraded when non-uniformity of excitation was considered. This was due to the quasi-static effects resulting from changes of subsoil geometry during the shock. The analysis indicated that the classical assumption of uniform excitation may lead to non-conservative assessment of the dynamic response of the shell described with concrete damaged plasticity model.
Experimental Research on Dynamic Mechanical Properties of 5083 Aluminum Alloy
Authors: Zhu Zhi Wu , Kang Guo Zheng , Ruan Dong , Ma Yue , Lu Guo Xing
Published: March 2013

5083 aluminum alloy was investigated with respect to its uniaxial dynamic compressive properties over a range of strain rates using the split Hopkinson pressure bar (SHPB). The dynamic stress-strain curves of this alloy were obtained for strain rates from 1000 s-1 to 6000 s-1. Effects of strain rate, the samples size and anti-impact capability were analyzed. The experimental results show that under impaction loading, 5083 aluminum alloy has a remarkable strengthening response to strain rate and size; in particular, the responded stress increases with increasing strain rate, which implies that this alloy has high strength and high anti-impact capability.
Microstructure Evolution of Ti-46.5Al-2Nb-2Cr at Different Strain Rates and Temperatures
Authors: Zan Xiang , Wang Yu , He Yue Hui , Liu Yong , Song Wei Dong
Published: March 2013

The microstructure evolution of Ti-46.5Al-2Nb-2Cr with different microstructure types loaded under a large range of strain rates and elevated temperatures is investigated by TEM. The results show that deformation twins are the main deformation mode under high strain rate loadings and both ordinary dislocation and super-dislocation are the additional modes under quasi-static loadings. The proportion of twinned grains increases with the increased strain rates.
Response of 1100-H12 Aluminum Targets to Varying Span and Configuration
Authors: Iqbal M.A. , Tiwari G. , Gupta P.K.
Published: March 2013

The influence of target span as well as configuration was studied with 1 mm thick 1100H12 aluminum target subjected to19 mm diameter ogive nosed projectile impact. The effective span of 1 mm thick monolithic target was varied as 95, 190, 285, 380 and 475 mm. The configuration of 255 mm span diameter target was varied as 1 mm thick monolithic, double layered in-contact (2 x 0.5 mm) and double layered spaced. The spacing between the layers was also varied as 2, 5, 10 and 20 mm. The target was impacted normally by ogive nosed projectile to obtain the ballistic limit, failure mode and deformation. The ballistic limit was found to increase with an increase in span diameter. The monolithic target offered highest ballistic limit followed by layered in-contact and spaced targets respectively. The variation of spacing between the layers did not have significant influence on the ballistic limit.
Analysis of Slope Failure Mechanisms Considering Micropile-Soil Interaction
Authors: Liao Hong Jian , Tian Cheng Lin , Li Hang Zhou
Published: March 2013

A large scale model test was carried out in loess slope, in which the stress and deformation characteristics of slopes reinforced with different arrangements of micropiles were studied. The mechanism of the micropile-soil interaction and the reinforcement effect of micropiles in loess slope were analysed. Based on the scale of in-situ loess slope and the physical mechanics parameters of loess soil, a numerical model was established by using finite difference method. For a reasonable arrangement of micropiles in step-shaped slope, the critical slip surfaces were determined considering the influence of slope inclination, ratio of step height and loading position. The micropiles were arranged in the step-shaped slope based on the critical slip surface, and the relationship between the ultimate bearing capacity of slope and shear strength parameters of loess soil was studied. The maximum shear strain of micropile-soil and moment of micropiles were calculated, and then the mechanism of the micropile-soil interaction was analysed.
Investigation on the Damage Process and the Deformation of Concrete Using Meso Element Equivalent Method
Authors: Jin Liu , Du Xiu Li , Ma Guo Wei
Published: March 2013

The meso-element equivalent method (MEEM), is developed in the study to investigate the damage process and the macro-mechanical properties of concrete. The Monte Carlo method is adopted to generate the random aggregate structure (RAS) firstly, and then the characteristic element size is applied to divide the RAS into many identical units. Each unit obtained is processed equivalently to be a homogeneous and isotropic unit by the homogenization theory. Some concrete specimens in 2-D and 3-D are undertaken to verify the feasibility and accuracy of the proposed approach. The results indicate the high efficiency and accuracy of the present methodology.
Analysis on Perforation of Ductile Metallic Plates by APM2 Bullets
Authors: Chen Xiao Wei , Gao Y.B. , He L.L.
Published: March 2013

By employing the theoretical model of a rigid sharp-nosed projectile perforating the ductile metallic target plate, the present paper re-analyzes the previously published experimental data of APM2 bullet and its hard steel core perforating aluminum armor plates and high-strength steel plates, respectively. Although the bullet deforms during the perforation, the test confirms that the hard steel core dominates in the perforation but the brass jacket, lead cap and end cap only have limited influence on the ballistics. Therein the perforation model of a rigid sharp-nosed projectile may be conducted to analyze the perforation of APM2 bullet. With increasing the thickness of ductile metallic target plate, the inertia effect of target will arise and obviously affect the terminal ballistics. The inertia effect of target must be considered in the scenario of thick target plate.
Impact Loading on Glass/Epoxy Composite Laminates with Nano Clay
Authors: Velmurugan Ramachandran , Balaganesan G. , Gupta N.K.
Published: March 2013

This paper presents various energy absorbing modes in nano composite laminates when subjected to impact loading. Composite laminates, made of 610 gsm WRM(Woven Roving Mat), are prepared by hand lay-up and compression molding technique.Nano clay is dispersed in epoxy and is used as a matrix. Clay dispersion in epoxy is varied from 1% to 5% by weight. A gas gun set up is used to impact the composite laminates with spherical nose cylindrical projectile of diameter 9.5 mm and mass 7.6g.The laminates are subjected to different velocities, which vary from below ballistic limit to above ballistic limit.The vibration response of the laminate at different impact velocities is studied. A time dependent analytical model is used to predict the projectile energy during penetration, and is used to determine the ballistic limit of the laminate. The ballistic limit obtained from experiment is validated with analytical model and good agreement is found.
Large Deformations of Inelastic Shells
Authors: Altenbach Holm , Eremeyev Victor A.
Published: March 2013

In this note we discuss the derivation of two-dimensional governing equations of a nonlinear shell made of material containing continuously distributed dislocations.We apply the trough-thethickness integration procedure to a nonlinear shell-like three-dimensional body with dislocations. This procedure gives the exact equilibrium equations with the stress resultant and couple stress tensors. The dual to the surface stress tensors are the surface strain measures which are represented by two surface fields. The first one is the translation vector of the base surface of the shell while the second field is the proper orthogonal tensor expressing rotation of the shell cross-section. Since in the case of solids with dislocations there are no displacement vector field. These fields are interpreted as quantities defined on the nonmaterial base surface of the shell.
Dynamic Compression of Buffer Plates Impact by a High Velocity Sand Spray
Authors: Deshpande Vikram , Liu Tao
Published: March 2013

The response of back-supported buffer plates comprising a solid face sheet and foam core backing impacted by a column of high velocity particles (sand slug) is investigated via a lumped parameter model and coupled discrete/continuum simulations. The numerical calculations show that the momentum transfer is minimised for intermediate values of the core strength when the so-called “soft-catch” mechanism is at play. In this regime the bounce-back of the sand slug is minimised which reduces the momentum transfer. The results demonstrate that appropriately designed buffer plates have potential as impulse mitigators in landmine loading situations
Electrical Characteristics and Microstructures of Bi2.9Pr0.9Ti3O12 and Bi2.9Pr0.92Ti2.97V0.03O12 Thin Films
Authors: Chen Min , Mei X.A. , Liu Rui Fang , Huang C.Q. , Liu J.
Published: March 2013

Bi2.9Pr0.9Ti3O12(BPT) and Bi2.9Pr0.9Ti2.97V0.03O12(BPTV) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique. These samples had polycrystalline Bi-layered perovskite structure without preferred orientation, and consisted of well developed rod-like grains with random orientation. The experimental results indicated that Pr doping into Bi4Ti3O12 (BIT) result in a remarkable improvement in ferroelectric property. The remanent polarization (Pr) and coercive field (Ec) of the BPT film were 28 μC/cm2 and 80 kV/cm, respectively. Furthermore, V substitution improves the Pr value of the BTVT film up to 43 μC/cm2, which is much larger than that of the BPT film.
Morphological and Optical Properties of CdS Nano-Crystalline Thin Films by Chemical Bath Deposition
Authors: Liu Yi , Wei Ai Xiang , Lin Xiao Dong
Published: March 2013

CdS thin films were prepared by chemical bath deposition (CBD) at different ammonia concentration and different temperature using cadmium chloride hydrate, thiourea, ammonium chloride, ammonia and deionized water as precursors. The morphology structure and the optical properties of CdS thin films were characterized by scanning electron microscope (SEM), ultraviolet-visible spectra and spectroscopic ellipsometry. The results indicated that CdS thin film could be grown when ammonia concentration at the range of 0.4-1.0 mol /L and in the temperature range of 50 °C -80 °C. Within 600-980 nm wavelength，the average value of the refractive index was found to be 1.70 and the extinction coefficient was less than 0.08.
Determination of Thickness of PZO Films Deposited on ITO Glass Substrates
Authors: Li Xue Jiao , Zhang Cheng , Zhang Na
Published: March 2013

PZO (PbZrO3) coatings with different thicknesses were deposited onto Indium Tin Oxide ITO glass substrates at room temperature by magnetron sputtering technique. UV-Vis absorption spectra method and microhardness testing method were used to measure the thickness of coating. It was proved that the measuring results of film thickness by two kinds of methods were equivalent, and either one method can be alternatively used to determine the thickness of deposited films.
The Process Optimization and Structural Analysis of Gasochromic Thin Films Derived by Peroxopolytungstic Acid
Authors: Feng Wei , Wu Guang Ming , Gao Guo Hua , Zhang Zeng Hai
Published: March 2013

The sol-gel method with a combination of dip-coating process was employed to prepare peroxopolytungstic acid gasochromic thin films. The influence of preparation process on the structural and gasochromic durability was then discussed. We found that hydrogen peroxide content shown a significant impact on the structure of tungsten oxide thin films, which directly determined the gasochromic durability
Preparation and Characterization of TiO2 Film on Glass Flake
Authors: Guo Yi , Du Shi Guo , Yan Jun , Wang Bin
Published: March 2013

A TiO2 film was prepared on glass flake with Ti(OBu)4 as a main material by peptization and reflux method at 80°C in acidic abundant aqueous solution. The surface topography and surface phase structure were characterized by scanning electron microscope, energy spectrum, X-ray diffractometer, X-ray photoelectron spectroscope, and the bonding strength between film and glass flake was researched by ultrasonic vibration. The results indicated that the TiO2 film, the main phase was anatase and a little rutile, coated on the glass flake uniformly. Along with growth of TiO2 on surface of glass flake, the formation maybe base on two different mechanics, at the earlier stage, TiO2 coupled surface of glass flake with Si-O-Ti chemical bond, but with physical deposition at final.
Structural and Optical Properties of Pulse Laser Deposited TiO2 Thin Films
Authors: Liu Yi , Huang Hong Mo , Lin Xiao Dong
Published: March 2013

TiO2 thin films were prepared on quartz glasses by pulsed laser deposition (PLD) using a KrF laser excimer. The crystalline structure was characterized by X-ray diffraction, and the optical properties of the films were investigated using spectroscopic ellipsometry and UV-vis spectra respectively. The effects of the PLD conditions, including substrate temperature and O2 pressure on the crystalline structure and the optical properties of the films were investigated. The results indicated that there are a suitable substrate temperature and an O2 pressure which is favorable for the synthesis of anatase-type TiO2.
Synthesis and Characterization of Nanostructured Co(OH)2 and Co3O4 Thin Films by a Simple Solution Growth Process
Authors: Liu Yu Xin , Li Qun Yan , Nie Zuo Ren , Wei Qi
Published: March 2013

Nanostructured Co(OH)2thin films were synthesized by a simple solution growth process. In experiment, F–and NH3were used as Co2+ordination agents, and hydroxyl ions were supplied by ammonia hydroxide solution for the hydrolysis reaction. The results showed that the solution pH and F/Co ratio had great influences on the morphologies of the thin films. The Co(OH)2thin films were constructed with lots of Co(OH)2nanoflakes. Nanostructured Co3O4 thin films were prepared by annealing the Co(OH)2thin films at 400°C for 2 h. The magnetic properties of Co3O4thin films were also investigated.
Preparation and Characterization of Inorganic Zinc-Rich Coatings Based on Geopolymers
Authors: Li Xin Feng , Cui Xue Min , Liu Si Dong , Mo Bing Hui , Cui Li
Published: March 2013

In this work, a high performance, environmentally friendly and waterborne inorganic zinc-rich coating based on geopolymer was developed and applied as protective coating of steel substrate. The geopolymer was the main ingredient of the zinc-rich paint (ZRP), and the zinc powder and additives were added to geopolymer to prepare ZRP. The corrosion protection behaviors of ZRP with different kinds of zinc powder and various zinc contents were characterized by electrochemical protection performance test. The results showed that coatings with 55 wt% spherical zinc powder and 25 wt% lamellar zinc powder exhibited good corrosion resistance mainly because of the cathodic protection and barrier effect.
Oxidation Resistance and Plating Encapsulation of Cu-Based Alloys as Phase Change Materials for High-Temperature Heat Storage
Authors: Zhang Guo Cai , Li Jian Qiang , Ma Bing Qian , Xu Zhe , Peng Zhi Jian , Chen Yun Fa
Published: March 2013

Cu-based alloys have been regarded as one of the most promising phase change materials (PCMs) in industrial waste heat recovery and solar thermal electric generation. In this paper, the oxidation behavior and the containment of liquid Cu were investigated. It was found that with the small addition of aluminum, the oxidation resistance of Cu-based PCMs was greatly enhanced. Notably, its latent heat density remained high. The containment of PCMs was achieved by depositing a Ni-base exterior coating on Cu spheres through barrel plating, rack plating and electroless plating processes. The deposition rates, surface topography, and the crystallography of the coatings depended largely on the plating process. The cyclic thermal was tested at last.
Fabrication of Zirconia Coating on the Surface of Al2O3-SiC-C Castable
Authors: Yin Yu Cheng , Liang Yong He , Ge Shan , Lu Jiu Chang , Liu Zhi Qiang
Published: March 2013

Using zirconia Sol as zirconia source, zirconia coating has been fabricated on the surface of Al2O3-SiC-C castable by spraying technology after pretreated at 110oC, 300oC, 500oC, 700oC and 900oC. The oxidation resistance of Al2O3-SiC-C castable with zirconia coating was compared with that without coating, at the same time using microanalysis technique, effects of pretreatment temperatures and spraying times on the fabricated zirconia coating were investigated. Results suggest that better zirconia coating might be achieved after pretreated at 300oC and spraying one time. At this condition, fabricated zirconia coating has good continuity, closely bonded with substrate castable and even has a little penetration into the castable, and thus improved the oxidation resistance of Al2O3-SiC-C castable.
Synchrotron Radiation Topography on Domain Structure Induced by DC Electric Field in PZNT Ferroelectric Crystals
Authors: Xiao Jing Zhong , Paixão José António Carvalho , Yuan Qing Xi , Huang Wan Xia , Zhu Pei Ping
Published: March 2013

The ferroelectric domain’s structure and its evolution processes induced by DC electric field in 0.92Pb（Zn1/3Nb2/3）O3-0.08PbTiO3（PZNT）crystal is observed using synchrotron radiation white-beam topography. Two organic plates with tinsels covering their surfaces are used as electrodes to employ DC electric field, and the characterizing sample is two PZNT crystal slices whose surface orientation is [111] and [001], respectively. This research results is considered to be useful for demonstrating the electric field induced phase transition in PZNT crystals.
Preparation, Characterization and Thermal Property of Novel Dendritic Liquid Crystal Macromolecule
Authors: Wang Qing , Zhao Hao , Chen Cai Hong , Xu Ji Cheng , Yang Dong Ya , Qiu Feng Xian
Published: March 2013

A monomer 4,4'-bis(β-hydroxyethyl)biphenyl (2BP) was synthesized by the Williamson reaction from 2-chloroethanol and 4,4'-biphenol. Then, the novel dendritic liquid crystal macromolecule (DLCM) containing biphenyl structure was synthesized with 2BP and 1,3,5-benzenetrimethylacylchloride as monomers by dispersion method. The structures of 2BP and the DLCM were characterized by FT-IR and 1H-NMR. The thermal stabilities of he DLCM were measured by TGA and DSC. The results showed that the DLCM had good thermal stability and the DLCM may have a higher phase inversion temperature.
Thermal Cycling Effect on Mechanical Properties of Yttria-Stabilized Tetragonal Zirconia
Authors: Zhang Jing
Published: March 2013

Yttria-stabilized zirconia (YSZ) is an important material in the area of energy and optical applications. In this study, the mechanical properties (Young’s modulus, Vickers hardness, flexural strength, and coefficient thermal expansion) and physical properties (phase transition) of yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) was reported. The effect of thermal cycling on the mechanical properties and the stability was also evaluated.
Preparation and Properties of Waterborne Cationic Polyurethanes/Polypyrrole Conductive Composites
Authors: Wang Hai Hua , Hu Jin Juan , Shen Yi Ding , Fei Gui Qiang , Zhang Juan
Published: March 2013

A series of waterborne cationic polyurethanes dispersions (CWPU) was prepared through prepolymerization method by reacting polyethylene glycol (PEG1000) and isophorone diisocyanate (IPDI) with N-methyl diethanol amine (MDEA) as chain extender. Then FeCl3 was employed as oxidant, therefore CWPU/polypyrrole (CWPU/PPy) conductive composite was prepared by in situ chemical oxidative polymerization of pyrrole (Py) in CWPU dispersions. Effects of molar ratio of FeCl3 to Py, Py concentration on the resistivity of the CWPU/PPy composite films were investigated. The structure, morphology and thermal stability were also characterized by Fourier infrared spectra (FT-IR), light scattering, TEM, and TGA. FT-IR demonstrated the presence of hydrogen-bonding interactions between CWPU and PPy. The average particle size of CWPU/PPy increased from 10.61nm to 30.29nm compared with pure PU, and corresponding size distribution decreased from 0.850 to 0.346. It was also found that CWPU/PPy displayed as spherical morphology, and no aggregation among particles was detected among particles. TGA certified CWPU/PPy was endowed with better thermal stability. In addition, conductivity stability of composites films was also studied. It was found that composite films not only displayed low resistivity but also improved conductivity stability.
In Situ Thermal Oxidation Route to SnO2 Nanostructures
Authors: Guo Tian Hong , Li Juan , Zhang Yong Cai , Yang Zhan Jun
Published: March 2013

An in situ thermal oxidation strategy was proposed for synthesizing different SnO2 nanostructures, using our homemade SnS2 nanoplates as a precursor. The characterization results from X-ray diffraction, energy dispersive X-ray spectroscopy, and field emission scanning electron microscope revealed that the heating temperature played an important role in the microstructure and composition of the resultant products. By heating the SnS2 nanoplates in air at 400, 600 and 800 °C for 5 h, nanoplates, a mixture of nanoplates and nanoparticles, and nanoparticles of SnO2 were synthesized, respectively. The residual S was about 2.2 mol % in the product synthesized at 400 °C, while no residual S was detected in the products synthesized at 600 and 800 °C.
Electrochemically Reduced Graphene Oxide Film Modified Electrode for Detection of Hydrogen Peroxide
Authors: Li Juan , Yang Juan , Yang Zhan Jun , Ji Ping , Zhou Yi Mei , Diao Guo Wang
Published: March 2013

A novel electrochemical method was proposed for detection of hydrogen peroxide (H2O2) based on electrochemical reduction of graphene oxide (GO) modified glassy carbon electrode (GCE). The electrochemically reduced graphene oxide (RGO) was characterized using cyclic voltammetry (CV). Under the optimized conditions, the RGO modified GCE showed much wide linear range for H2O2 from 2.0 to 600 M with the detection limit of 0.67 M (S/N = 3). The proposed method is simple, low-cost and convenient and will be a promising alternative for H2O2 sensing.
Low-Temperature Synthesis of Nano-Crystalline MgTi2O5 Powders by Aqueous Sol-Gel Process
Authors: Chen X.F. , Li J. , Feng T.T. , Jiang Y.S. , Zhang X.H. , Wu H.T. , Yue Y.L.
Published: March 2013

The pseudobrookite-structure MgTi2O5was successfully synthesized by the aqueous sol-gel method using titanium dioxide and magnesium nitrate as starting materials instead of expensive organic solvent and metal alkoxides. The as-prepared nanopowders were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA) and transmission electron microscope (TEM), respectively. The results showed that the calcinations process of gel consisted of a series of oxidation and combustion reactions, accompanied by significantly exothermal effects. Highly reactive nanosized magnesium titanate powders were successfully obtained at 650 °C with less than ~100 nm.
Photo- and Thermo-Dual-Responsive Organic/Inorganic Hybrid Materials
Authors: Tang Xin De , Chen Ye , Yu Fa Qi , Pei Mei Shan
Published: March 2013

Organic/inorganic hybrid materials based upon stimuli-responsive copolymers have attracted an inceasing attention. Compared with the polymeric materials, these hybrid materials can form aggregates in aqueous solution with much more stable shape-persistance due to the inorganic structure, which facilitate the mass delivery and long-term life. A novel hybrid material based on a new reactive block copolymer, poly(ethylene oxide)-block-poly{3-(trimethoxysilyl)propyl methacrylate-co-N-isopropylacrylamide-co-6-[4-(4-methoxyphenylazo)phenoxy]hexyl methacrylate} [PEO-P(TMSPMA-NIPAM-AzoMA)] was synthesized via atom transfer radical polymerization (ATRP). The vesicles were obtained by self-assembly of the resulting block copolymer in a selective solvent, and then the PTMSPMA block was subjected to hydrolysis and polycondensation reaction to fix vesicle wall in the presence of triethylamine as a catalyst. The photo- and thermo- dual-responsive properties of the vesicles were investigated.
Effect of Hydrothermal Synthesis Time and Solvent Replacement on ZrO2 Sols
Authors: Wang Sheng Zhao , Yin Ying Peng , Chen Lan Li , Nan Chun Juan
Published: March 2013

ZrO2 sols were obtained by hydrothermal synthesis. With different hydrothermal synthesis time, ZrO2 particle size varied from 5nm to 16nm. And ZrO2 thin films were prepared with spin coating method. ZrO2 thin films were characterized or examined by many kinds of instruments. And 1-on-1 laser-induced damage threshold tests on ZrO2 films were carried out. Refractive index and thickness of the ZrO2-PVP films were measured by means of automatic scanning spectroscopic ellipsometer and the refractive index of ZrO2 -PVP film changed with the addition of PVP content.
Influence of Cladless Hot Isostatic Pressing on Magnetic Properties and Corrosion Resistance of Sintered NdFeB Magnets
Authors: Liao Zhi Qin , Xu Feng , Yan Wei Jin , Huang Qi Jun , Chen Guang , Li Shan Dong
Published: March 2013

In this work, the cladless hot isostatic pressing (HIP) is performed on sintered NdFeB magnets. After the processings, the density of the magnets is slightly increased. The statistics of microstructure shows the growth of grains. The evaluation by X-ray diffraction shows that the alignment degree of grains decreases. These effects slightly improve the magnetic energy products, meanwhile bring about the deterioration of coercivity. Corresponding to the increase of density, the corrosion resistance checked by electrochemistry method becomes better after HIP processings.