bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Interfaces and Cr Diffusion on Stabilizing Cu Conductivity in Nb3Sn-Strands
Authors: Popova E.N. , Deryagina I.L. , Polikarpova M.V. , Novosilova D.C. , Vorobyova A.E.
Published: March 2013

The structure of high-purity copper and stabilizing copper of Cr-plated Nb3Sn-strands with different RRR (residual resistance ratio) values has been studied. Cr diffusion into peripheral layers of stabilizing Cu has been revealed. The variations of RRR and Cr content in Cu at annealing have been estimated. It is demonstrated that an additional drop of RRR may be caused by oxygen diffusion from Cr coating obtained by electroplating. Optimal regimes of the diffusion annealing of Cr-plated Nb3Sn-strands for ITER (International Thermonuclear Experimental Reactor) have been determined.
Influence of Heat Treatment on Corrosion Resistance of the ZnAl22Cu3 Alloy
Authors: Michalik Rafał , Woźnica H.
Published: March 2013

Zn-Al-Cu type alloys are characterized by a number of advantageous properties which include: good castability, good tribological properties, low energy value needed for forming of the product. As compared to bronze, Al-Zn-Cu alloys are characterized by a lower density. Improved properties of Zn-Al alloys can be obtained by addition of copper and silicon. Advantageous results can also be obtained by heat treatment. There is an extensive literature on the effect of heat treatment upon the structure of Al-Zn-Cu alloys. However, few articles discuss the effect of heat treatment on the corrosion resistance of alloys. The purpose of this examination was to determine the effect of heat treatment on corrosion resistance of ZnAl22Cu3 alloy. The unmodified alloy containing 22% Al mass. and 3%. Cu (Zn - remain) was subjected to the examinations. Tested alloys underwent the following operations: soaking at the temperature of 185°C for 10 hours with cooling in water, soaking at the temperature of 380°C for 10 hours with cooling in water and soaking at the temperature of 380°C for 10 hours with subsequent soaking at the temperature of 170°C with cooling in water. Potentiodynamic and potentiostatic examinations in a solution of acid rain with pH = 3.5 were carried out. Then the tests were followed by examination of the corroded sample surface.The carried out examinations showed a decrease in corrosion resistance after heat treatment at the temperature of 380°C and a slight increase after heat treatment at the temperature of 185°C.
A Contaminant Transport in Partially Saturated Porous Media
Authors: Kačur Jozef , Minár Jozef
Published: March 2013

We model the flow of the contaminated water through the porous media sample. We model the inflow of water, flux of water in the sample, flux of the contaminant in the water in the sample, adsorption of the contaminant in the sample and the outflow of the contaminated water from the sample. During the process, there appears fully saturated zone, partially saturated zone and dry zone. We consider Darcys law for flux of the water in fully saturated zone and Richards equation for flux in the partially saturated zone. Flux of the contaminant is governed by Ficks law and the adsorption of contaminant is modeled using Freundlich isotherm. Problem is solved in 1D using numerical solution based on the MOL method. Since flow of the water is independent of the contaminant, we compute separately saturation in the whole time interval and then contamination of water and adsorption of contaminant in the sample.
Wetting and Drying of External Surfaces with ETICS Systems
Authors: Barreira E. , Delgado João M.P.Q. , de Freitas V.P.
Published: March 2013

Moisture is one of the most deteriorating factors of buildings. The deteriorating effect of moisture occurs mainly during the drying phase, and appropriate parameters of the drying kinetics are required for the building materials. Environmental factors, such as air temperature and air humidity affect drying. An experimental campaign was performed to investigate the drying performance of External Thermal Insulation Systems (ETICS). Drying kinetics was examined at three air temperatures, four solar orientations and two different air humidities. A first-order kinetics model was obtained, in which the drying time constant was a function of the drying conditions, and the equilibrium material moisture content was described by several different models, such as linear type, power type, exponential type, Arrhenius type and Logarithmic type. The parameters of the proposed model were found to be affected strongly by the material and the drying air conditions.
Chemical Kinetics between Brine and Rock Salt Transitions
Authors: Promkotra Sarunya
Published: March 2013

The chemical kinetics dissolution of rock salts from Sakon Nakhon Basin is characterized by drill cores and compared to geochemical compositions of natural brines obtained within the study areas in Udon Thani and Sakon Nakhon Province, Thailand. A criterion for rock salt core analysis depends upon the maximum amount of halite, based on X-ray diffractometry. Mass balance relation between brines and rock salt dissolution is conducted by the difference of initial and final weights of the core sample in each experimental batch. To monitor salinity related to its dissolution, the concentrations of total dissolved solids (TDS) are determined for each time period. The dissolution rate of rock salts can be evaluated from chemical compositions of the reactants; sodium-chloride (Na-Cl, halite) and calcium-sulphate (Ca-SO4, anhydrite), corresponding to the TDS content, against the experimental variables of time and temperature. The most important aspect of brine and rock salt interfaces concerns the chemical kinetics developed for the rate of reaction (R) and rate constant (k) as R = k [NaC0.7[CaSO4]0.8. The overall order of the reaction is experimentally 1.5 with respect to concentration of sodium chloride and calcium sulphate. Phase transitions based on the behavior of the thermodynamic free energy as a function of thermodynamic variables are accompanied by the release of heat. The activation energy needs for the dissolution reaction of rock salt is-18.08 kJ/mol. The experimental result indicates the exothermic reaction, similar to the calculation by theoretical thermodynamics. Saturation indexes of brines as a function of anhydrite reveal the supersaturating condition while rock salt dissolution reaches the equilibrium condition.
Comparison of Nanosized Pattern of Calixarene and ZEP520 Resists by Using Energy Deposition Distribution
Authors: Zhang Hui , Komori Takuya , bin Mohamad Zulfakri , Yin You , Hosaka Sumio
Published: March 2013

We numerically modeled the process of exposure and development of the calixarene negative resist and ZEP520 positive resist in electron beam lithography (EBL) in order to understand the limitation of nanopatterning of these two resists and to improve the resolution of the patterning. From the calculation of energy deposition distribution (EDD) in resist at various beam diameters, it is obvious that the fine probe beam with a diameter of 2 nm and thin resist should be adopted for formation of very fine dots. The simulation of resist development profile indicates that a dot size of 2 nm with a pitch of 20 nm can even be obtained at a higher critical energy density by using calixarene resist, while it cannot form the small pattern by using the ZEP520 resist because of the capillary force.
Measurement of Coercive Force Enhanced by Nanometer-Sizing of Magnetic Dot by X-Ray Magnetic Circular Dichroism (XMCD)
Authors: Hosaka Sumio , bin Mohamad Zulfakri , Yin You , Sakurai Hiroshi , Kondo Yuji , Ariake Jun , Honda Naoki , Suzuki Motohiro
Published: March 2013

We have studied the coercive force of fine magnetic CoPt dot enhanced by nanometer-sizing of the dot. The 39-to 106-nm-sized CoPt magnetic dot arrays were formed by30-keV-electron beam (EB) drawing with thin calixarene resist and 200-eV-Ar ion milling. Using the fine magnetic dot arrays, we measured coercive forces of the dot by x-ray magnetic circular dichroism (XMCD) with an energy of 11.56 keV, which corresponds to an energy edge of Pt-L3. It is experimentally demonstrated that a coercive force of the nanometer-sized magnetic column increased as the dot diameter decreased. Keywords: Coercive force, nanomagnetic column, XMCD, magnetic storage, EB lithography
Improved Observation Contrast of Block-Copolymer Nanodot Pattern Using Carbon Hard Mask (CHM)
Authors: Akahane Takashi , Komori Takuya , Liu Jing , Huda Miftakhul , bin Mohamad Zulfakri , Yin You , Hosaka Sumio
Published: March 2013

In this work, improvement of the observation contrast was investigated by using a carbon film as the hard mask for pattern transfer of block copolymer (BCP) nanodots. The PS-PDMS (Poly (styrene-b-dimethyl siloxane)) block copolymer was adopted here. The observation contrast was greatly improved after transferring block copolymer (BCP) nanodots pattern to the underlying Si substrate through the carbon hard mask compared that before nanodot pattern transfer. Pattern transfer was also demonstrated to be very effective using carbon hard mask.
Multi-Level Storage in Lateral Phase Change Memory: From 3 to 16 Resistance Levels
Authors: Yin You , Alip Rosalena Irma , Zhang Yu Long , Kobayashi Ryota , Hosaka Sumio
Published: March 2013

Here, we report multi-level storage (MLS) in multi-layer (ML) and single-layer (SL) phase change memories (PCM). For the former ML-PCM device, the active medium with two layers of chalcogenide consists of a top 30 nm TiN/180 nm SbTeN/20 nm TiN/bottom 120 nm SbTeN stacked multi-layer. Three stable and distinct resistance states are demonstrated in both static and dynamic switching characteristics of the multi-layer devices. For the latter SL-PCM device, the active medium with only one layer of chalcogenide consists of a top 50 nm TiN/150 nm SbTeN. We demonstrate that the number of distinguishable resistance levels can readily reach 16 and even higher. These levels in this study result from the initial threshold switching and the subsequent current-controlled crystallization induced by Joule heating. Therefore, the latter memory allows the creation of many distinct levels, thus enabling the low-cost ultra-high-density non-volatile memory.
A Novel Phase Change Memory with a Separate Heater Characterized by Constant Resistance for Multilevel Storage
Authors: Alip Rosalena Irma , Kobayashi Ryota , Zhang Yu Long , bin Mohamad Zulfakri , Yin You , Hosaka Sumio
Published: March 2013

A novel phase change memory structure with a separate heater was proposed for a multilevel storage. Finite element analysis was conducted to investigate the possibility of multilevel storage. 100 ns SET pulses, with an increasing amplitude from 0.5 V to 3 V, were applied for heating the phase change layer, Ge2Se2T5 (GST). From the simulation result, it was exhibited that the temperature in the GST layer increased gradually when an increasing pulse is applied to the separate heater layer (N-TiSi3). This implies that crystallization is well controlled by changing the amplitude of the applied SET pulse. The gradual increase in the temperature leads to gradual resistance drop, depending strongly on the capping material. The gradual resistance drop will allow multilevel storage for the memory device.
Growth of SiOx Nanowires by Simple Vapor Transport Method and their Optical Properties
Authors: Hakamada Yuto , Ozaki Shunji
Published: March 2013

SiOx nanowires were grown on Si substrates by a simple vapor transport method of heating the mixture of silicon monoxide and carbon powders at 1000 °C in a tube of the furnace. The dependence of the growth velocity on the growth temperature and on the radius of nanowires indicates that the SiOx nanowires grow through the vaporliquidsolid (VLS) growth mechanism. The properties of the nanowires are characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL).
Fabrication of Mach-Zehnder Polymer Waveguides by a Direct-Drawing Technique Using a Focused Proton Beam
Authors: Miura Kenta , Satoh Takahiro , Ishii Yasuyuki , Kiryu Hiromu , Ozawa Yusuke , Kohka Masashi , Takano Katsuyoshi , Ohkubo Takeru , Yamazaki Akiyoshi , Kada Wataru , Yokoyama Akihito , Kamiya Tomihiro , Hanaizumi Osamu
Published: March 2013

Proton beam writing (PBW) has recently attracted much attention as a next-generation microfabrication technology. This is a direct-drawing technique and does not need any masks to transfer micropatterns to sample surfaces. In our previous work, we demonstrated the first single-mode straight-line and Y-junction PMMA-based waveguides fabricated using PBW and working at λ = 1.55 μm. In this work, we fabricated the first PMMA-based Mach-Zehnder waveguides for the wavelength utilizing PBW in order to construct thermo-optic switches.
Design and Analysis of Taper Structure for Light Coupling into Photonic Crystal Waveguides Fabricated by Si-Ion Implantation
Authors: Umenyi Amarachukwu Valentine , Kikuchi Shusuke , Sasaki Tomoyuki , Miura Kenta , Hanaizumi Osamu
Published: March 2013

In this paper, we designed and analyzed an efficient taper structure to couple light into and out of photonic crystal waveguides (PhCWs) fabricated by Si-ion implantation and electron beam lithography. The coupling structure employs the gentle refractive-index distribution produced in the SiO2layer by Si-ion implantation. A taper structure is designed for effective coupling of transverse electric (TE) polarized light (λ = 1.55 μm) into a submicron size PhCW consisting of triangular lattice of air holes (lattice constant,a= 0.666 μm, radius of air holes,r= 0.232 μm, waveguide width, W1 ~ 0.7 μm). The influence of the taper length on the transmission characteristics is investigated. Efficiency in excess of 95% is demonstrated using the finite-difference time-domain and beam propagation methods. This is important for their practical applications in photonic integrated circuits.
An Analytical Study on Jitter Accumulation in Interleaved Phase Frequency Detectors for High-Accuracy On-Chip Jitter Measurements
Authors: Niitsu Kiichi , Sakurai Masato , Harigai Naohiro , Hirabayashi Daiki , Oki Daiki , Yamaguchi Takahiro J. , Kobayashi Haruo
Published: March 2013

This work presents the analytical study on jitter accumulation in interleaved phase frequency detectors for high-accuracy on-chip jitter measurements. Jitter accumulation in phase frequency detector degrades the accuracy of on-chip jitter measurements, and required to be mitigated. In order to analyze and estimate the jitter accumulation in phase frequency detectors, SPICE simulation was performed with 65 nm CMOS technology. Simulation results show that, with a 50 mV power supply noise injection, jitter accumulation can be reduced from 1.03 ps to 0.49 ps (52% reduction) by using an interleaved architecture.
Synthesis of MnZn-Ferrite Using Coprecipitation Method
Authors: Hoshi Kazushi , Kato Hiroki , Fukunaga Takayuki , Furusawa Shinichi , Sakurai Hiroshi
Published: March 2013

Mn1-xZnxFe2O4(x= 0, 0.1, 0.2, 0.3, 0.4, 0.5) are synthesized using sintering coprecipitation method. The coprecipitation retains from 0 hours to 48 hours at 1200 °C. The synthesis of a Mn0.6Zn0.4Fe2O4is almost completed even though retaining time is for 0 hours at 1200 °C. The crystal growth of Mn0.6Zn0.4Fe2O4particles proceeds rapidly retaining up to 6 hours and saturates retaining more than 6 hours at 1200 °C. The permeability and the electric resistivity are affected by the crystal growth of Mn0.6Zn0.4Fe2O4particles.
Verification of Photochemically Induced Crystallization Mechanism of Proteins by Dimer Addition
Authors: Kuroiwa Takashi , Horiuchi Hiroaki , Hiratsuka Hiroshi , Okutsu Tetsuo
Published: March 2013

We investigated the light-induced crystallization mechanism of proteins. The photochemically produced protein dimer was thought to grow to a crystal size. This was proven experimentally in this study.
X-Ray Magnetic Diffraction Experiment of Fe3Pt Alloy in Order Phase
Authors: Naito Masahiro , Hiiragi Kenta , Sato Ayako , Maruyama Hiroshi , Ito Masahisa
Published: March 2013

We have performed X-ray magnetic diffraction experiments of a ferromagnetic binary alloy Fe3Pt in order phase, and have measured separately spin and orbital magnetic form factors. By a curve-fitting analysis in which atomic-model form factors of Fe-3d and Pt-5d electrons under the dipole approximation are assumed, we have obtained the spin and orbital magnetic moments of Fe and Pt atoms separately. The present result is comparable to those of other experimental and theoretical studies, which shows the validity of this experimental method.
Study of the Chemical Adsorption Property of Allylsilylazobenzene in the Surface Modification of Nanoporous Alumina Membrane
Authors: Kakiage Kenji , Saito Chie , Yamamura Masaki , Kyomen Toru , Unno Masafumi , Hanaya Minoru
Published: March 2013

In order to clarify the chemical adsorption property of allylsilane to metal-oxide surface quantitatively and to obtain the information on the reaction conditions for the efficient surface modification, chemical surface modification of nanoporous alumina membranes (NPAMs) by a typical allylsilyl compound of 4-(allyldimethylsilyl) azobenzene was examined. The chemical surface modification was performed by immersing NPAMs into the solutions of the allylsilylazobenzene. The modification was investigated precisely by estimating the amount of the silylazobenzene adsorbed on the NPAM surface using a visible absorption spectroscopy with changing the temperature, solvent, and the concentration of the solution to reveal the effects of the reaction conditions on the adsorption property of the allylsilane to the metal-oxide surface. The solutions with higher temperatures, non-polar solvents, and higher concentrations were shown to be suitable for the efficient surface modification.
Homogenized Elastic-Viscoplastic Behavior of Anisotropic Open-Porous Bodies
Authors: Ohno Nobutada
Published: March 2013

This lecture presents constitutive modeling of the homogenized elastic-viscoplastic behavior of pore-pressurized anisotropic open-porous bodies. The base solids are assumed to be metallic materials at small strains and rotations. First, by describing micro-macro relations relevant to periodic unit cells of anisotropic open-porous bodies with pore pressure, constitutive features are discussed for the viscoplastic macrostrain rate in steady states. Second, on the basis of the constitutive features found, the viscoplastic macrostrain rate is represented as an anisotropic function of Terzaghi’s effective stress. Third, the resulting viscoplastic equation is used to simulate the homogenized elastic-viscoplastic behavior of an ultrafine plate-fin structure and a thick perforated plate subjected to macroscopic loading in the absence and presence of pore pressure. The corresponding FE homogenization analysis is performed for comparison to validate the developed viscoplastic equation.
Effect of Temperature on the Dynamic Compressive Properties of Magnesium Alloy AZ91D
Authors: Ahmad Iram R. , Jing Xiao , Shu Dong W.
Published: March 2013

Lightweight materials are getting more and more attraction towards their use in automobiles, planes, protective structures, electronics and supports for numerous benefits ranging from reduction in fuel consumption in vehicles to lighter and stronger in protective structures. For efficient use of materials in applications where they are subjected to unusual higher sudden loads and varying temperatures, it is necessary to know their accurate response under such conditions. Magnesium alloys due to low density, high specific strength, high specific stiffness and damping capacity have been in use for variety of structural and non-structural applications mainly in automotive and aerospace industries along with many other applications in defense, supports and electronics. In present study, the effect of temperature variation has been investigated for magnesium alloy AZ91D at high strain rates. The temperature is varied in the range between -30oC to 200oC at a strain rate of 103 s-1. Lower stresses and larger strains to peak compressive stresses are observed with increasing temperature. At higher strain rate, the effect of temperature on the alloy’s hardening behaviour is less significant
A Numerical Approach to Shape Correction of Stamped Products Using Laser Forming Techniques
Authors: Song Jung Han , Zhang Y. , Lee J. , Lee Geun An , Lee Sang Mok , Lee H.W. , Park S.J.
Published: March 2013

Laser forming is an advanced process in sheet metal forming in which a laser heat source is used to shape the metal sheet. In this paper, shape correction of stamped product using the laser forming technique is numerically invesitgaed. As a fundamental study, laser irradiated bending process has been analyzed through the thermo-mechanical FE analysis. Laser scanning experiments has been also conducted for varificaiton of numerical simulations. Finally, the laser forming technique is applied to the u-shaped channel member for springback compensation. It is observed that laser irradiation gives the desired bending angle to compensate the springback by controlling the process parameters such as the laser power, scanning speeds and the number of laser scanning.
An Upsetting - Ironing Type Tribo-Meter for Evaluating Tribological Performance of Lubrication Coatings for Cold Forging
Authors: Hirose Masatoshi , Wang Zhi Gang , Komiyama Shinobu
Published: March 2013

In recent years, many attempts are being made to develop new lubrication coatings for cold forging. In general, an alternative coating is designed based on the results of the evaluation methods that simulate the frictional condition of cold forging. Various evaluation methods have been proposed and used to design an alternative coating according to the processing purpose. However a lot of parts are manufactured by the multistage forging machine such as parts forming machine, complex shape being produced recently by combined processing. A lubrication coating in such an environment is exposed to repeatedly in a variety of processing modes, and received serious damage. At present the performance of an alternative coating isn’t enough to satisfy needs of market in such a multistep forging. Development of lubricant that can satisfy such demands needs a new evaluation method. This comes the purpose of this study. An newly devised tribometer consists of an ironing process after upsetting process. We designed this test method by using finite element(FE) analysis. In upsetting, damage to the lubrication coating is given by the expansion of free surface. In ironing, the performance of lubrication coating destroyed by upsetting is evaluated. By using the upsetting-ironing type tribometer, the lubrication performance under a large surface expansion and a high pressure can be evaluated. In addition, the degree of coating damage can be adjusted by changing upset ratio and height of billet. The difference in the lubrication performance of the bonderised and the prototype alternative coating was examined by this evaluation method.
Mechanics of Stretchable Electronics
Authors: Zhang Yi Hui , Hwang Keh Chih , Huang Yong Gang
Published: March 2013

Recent advances in mechanics and materials provide routes to integrated circuits that offer the electrical properties of conventional, rigid wafer-based technologies but with the ability to be stretched, compressed, twisted, bent and deformed into arbitrary, curvilinear shapes. This paper summarizes developments in this emerging field, with descriptions of application opportunities, fundamental aspects, representative devices, and particularly the effect of plastic deformation.
Dimensional Changes by Heat Treatment of Helical Gear
Authors: Lim Jeongsuk , Kang Sunghoon , Lee Young Seon
Published: March 2013

The dimensional change of tooth profile by heat treatment of helical gear was investigated by experimental and numerical approaches. Especially, the three-dimensional elasto-plastic finite element (FE) simulation was adopted to analyze the elastic deformation during load, unloading, ejecting of workpiece. Quenching simulation was also carried out to investigate the change of tooth profile on the forged gear. In experiments, the amount of elastic deformation of the forged gear was quantitatively determined by comparing the tooth profiles on the forged gear and die. The dimensional change of the forged gear tooth after quenching was also evaluated from the comparision of the cold forged and quenched gear teeth. From experimental works, it was found that the amounts of dimensional changes after forging and quenching of helical gear are 10 and 10 μm, respectively.
Forming Limit of AZ31 Magnesium Alloy Sheet under Non-Proportional Deformation at Elevated Temperature
Authors: Katahira Takashi , Naka Tetsuo , Kohzu Masahide , Yoshida Fusahito
Published: March 2013

In the present work, FLDs of AZ31 magnesium alloy sheet for non-proportional strain paths were investigated by performing two-step stretch forming experiments at various forming speeds (3, 30 and 300 mm.min-1) at elevated temperatures of 150, 200 and 250°C. The forming limit strainSuperscript texts, both for proportional and non-proportional deformations, increased with temperature rise and with decreasing forming speed. A FLC after a uniaxial pre-strain lies outside of the proportional FLC for a given condition of temperature and forming speed, whereas a biaxially pre-strained FLC lies inside of the proportional FLC. It was found that the accumulated effective plastic strain and the direction of plastic strain increment at the final stage of forming are two major factors that influence the forming limits for non-proportional deformations.
What Happens beyond Drucker’s Proposition in Heterogeneous Media
Authors: Bai Yi Long , Ma Guang Wen , Hao Sheng Wang , Xia Meng Fen , Ke Fu Jiu
Published: March 2013

This paper briefly reviews our recent analytical and experimental results on 3 interrelated features beyond the peak load in heterogeneous media: continuous bifurcation, damage localization and catastrophic rupture (CR). Firstly, an Elastic Statistically-Brittle model (ESB) was introduced to formulate the basic features of a kind of heterogeneous media, like rocks and cements. The global mean field approximation (GMF) shows that the measure of heterogeneity, like the Weibull modulus m in the distribution of meso-strength plays a key role to distinguish CR from gradual failure. Then, with the ESB model and corresponding experimental results, continuous bifurcation and damage localization are discussed. In accord with these, regional mean field approximation (RMF) is adopted and it shows that any scale of damage localization can satisfy the conservation laws in continuum mechanics. This implies that catastrophic rupture could appear at any state beyond the peak load, depending on the unknown evolution of damage localization zone. Hence, catastrophic rupture seems to occur stochastically at macroscopic level. On the other hand, both experimental and analytic studies demonstrate that a robust power law singularity (-1/2) appears ahead of CR. Preliminary applications of these ideas are briefly described.
Damage of Plates due to Impact, Dynamic Pressure and Explosive Loads
Authors: Jones Norman
Published: March 2013

It is the purpose of this study to present design equations which can be used to predict the damage of ductile plating when subjected to mass impact, dynamic pressure or impulsive loadings. The external loadings are sufficiently severe to produce inelastic material behaviour and produce finite transverse displacement, or geometry change, effects. The damage is characterised as the final or permanent transverse displacement of a plate. The theoretical method predicts values for the maximum permanent transverse displacements which agree reasonably well with the corresponding experimental results generated on aluminium alloy circular, square and rectangular plates. Thus, the equations presented in this article are valuable for preliminary design purposes and for forensic studies, while the experimental data can be used for validating numerical schemes.
Development of Buffer Stopper Using Progressive Compression Process for Crash Energy Absorption of a Railway Vehicle
Authors: Ahn Kwanghyun , Huh Hoon , Kwon Tae Soo
Published: March 2013

A railway buffer stopper is a crash energy absorbing device which is installed at the end of rail lines in order to prevent derailment. To stop a train which cannot otherwise stop at the rail end due to some kind of trouble, this device should be installed in a railway station or depot where the rail line finishes. Friction type buffer stoppers have been installed at railway stations in most European countries. These devices can absorb the crash energy of the train by using the friction between a friction element and the rail when the train crashes into the buffer stopper. This paper proposes a new concept for the buffer stopper which can replace the friction type buffer stopper. More economical and effective buffer stopper can be suggested by using a progressive compression process. When the train crashes into the new type buffer stopper, a metal strip installed at the rail is progressively compressed and absorbs the kinetic energy of the train through its own plastic deformation. The feasibility of the buffer stopper using the progressive compression process is first investigated using numerical analysis and then the design and concept for the new system are suggested by a parametric study. The design of the progressive compression type has been verified by a series of experiments.
Deformation Behavior of Doubly Curved SS400 Thick Metal Plates by High Frequency Induction-Based Line Heating
Authors: Lee Kwang Seok
Published: March 2013

Line heating-induced deformation behavior of an SS400 thick plate was investigated through both numerical analysis and experimental counterpart by applying induction heating (IH) as a heat source. The drastic increase of temperature gradient upon increasing input power could mainly be predicted by numerical analysis, which attributes to the amount of permanent bending deformation of the thick plate. After plotting the amount of vertical deformation as a function of various positions from top surface of the plate, we found that the higher input power, the more thermomechanical deformation can be generated, regardless of the purposed doubly curved shapes such as concave and saddle-type plates. Also there is good agreement between the numerical analysis and experimental measurement in terms of the transverse curvature.
On the Strength of Angle-Patterned Sandwich Cores under Various Loading Conditions
Authors: Lu Xing , Wang Bin
Published: March 2013

Angled sandwich core made of thin aluminium sheets was analysed numerically to investigate their mechanical performace under various loading conditions. The stress distribution and deformation were compared with conventional hexgonal honeycomb cores of same relative density under various loadings. Possible failure modes are observed. The finding helps to provide a guidance to the design of ligthweight armour against explosive loading.
Deformation Mode Dependency on Strain Rate Sensitivity of Volume Resistivity in TRIP Steel
Authors: Iwamoto Takeshi , Yamanaka Shiro , Rusinek Alexis
Published: March 2013

With a phenomenon of strain-induced martensitic transformation, TRIP steel is expected to show excellent impact energy absorption characteristic. It is important for an improvement of a reliability of TRIP steel to evaluate an amount of martensite. In this study, AISI304, which is a kind of TRIP steel, is deformed plastically by a conventional material testing machine and the split Hopkinson pressure bar apparatus. During the deformation of TRIP steel, a circuit based on the Kevin double bridge measures change in volume resistivity which has a correlation with the amount of martensite. Experimental results show that the change in volume resistivity during the process of deformation at various strain rates.
Dynamic Characterization of a Fiber-Metal Laminate
Authors: Santiago Rafael Celeghini , Alves Marcilio
Published: March 2013

The mechanical strength of a fiber-metal laminate is not so well explored at high strain rates, although its constituents are prone to exhibit such effects. In this paper, we describe an investigation of aluminium-fiber glass material using the Split Hopkinson bar device. We report on various experimental issues related to these tests, giving some emphasis to the use of high speed filming to obtain information on the specimen strain and strain rate.
Dynamic Deflection of a Beam on Metal Foam
Authors: Xiang Xin Mei , Lu Guo Xing
Published: March 2013

An analytic model is developed to obtain the dynamic response of beams with initial velocities of the upper beam which is clamped at both ends and fully supported by metal foam, as a representative arrangement for protective structures. In large deflection, plastic bending and stretching in deforming regions are considered and the membrane factor method is introduced in the model to take into account the effect of axial force in the yielding. The relationships between the final displacement of the center in the beam and the dimensionless parameters are obtained. This model can predict the dynamic effects of different initial velocities and beams with different lengths, thickness and yield strength of cores.
Elasticity Effect in Dynamic Response of Beams with Pre-Cracks Impinged by Striker
Authors: Chen F.L. , Yu T.X. , Yang J.L. , Wu W.H.
Published: March 2013

To examine the effect of elasticity in dynamic response of imperfect structures, by densely setting meshes in the vicinity of the imperfections, pre-cracked beams impinged by a striker are modeled and numerically investigated. The dynamic response patterns and failure history for two specific configurations are obtained. It is found that complex alternations of the elastic-plastic stress distribution exhibit, and the striker is rebounded and then separated from the beam, which well reflects the effect of material elasticity. The high stress and large deformation zones, corresponding to the plastic hinges in the rigid-plastic model, appear at the impinging position and the supporting ends, and the locations coincide with those in the modal pattern in rigid-plastic response. From comparison, it is concluded that when the impinging is intense, despite the effect of elasticity displaying in the early stage, the widely employed rigid-plastic analysis is still capable of providing favorable prediction on the final response parameters.
Mechanics of Growing Solids and Phase Transitions
Authors: Manzhirov Alexander V.
Published: March 2013

Phase transitions can be usually observed in nature and technology which effectively utilize certain types of these transitions. An approach to modeling phase transition processes on the basis of the mathematical theory of growing solids is developed. Liquid-solid and gas-solid phase transitions are under consideration. Main attention is paid to the processes of solid phase growth and deformation.
Water-Quenching Thermal Shocking Property of Sm2Zr2O7/NiCoCrAlY Function Grade Thermal Barrier Coatings
Authors: Wang Xin Li , Bi Jian Ping
Published: March 2013

In the present manuscript, the influence of interface location, coating structure (layer number) and layer-material composition on water-quenching thermal-shocking property of Sm2Zr2 O7/NiCoCrAlY functional graded thermal barrier coatings (TBCs) were investigated using finite element method. Results show that radial thermal stress at surface of top-layer have the highest value. Radial thermal stress in TBCs decrease gradually with increase of layer number, and function graded TBCs have better thermal-shocking resistance compared with other TBCs. 1357 function graded TBCs have the most excellent thermal shocking resistance in these investigated TBCs in the current manuscript.
Investigation on the Representation Method for Microwave Absorbing Coat
Authors: Liu Heng , Zeng Zhao Yang , Guo Yi Ming
Published: March 2013

Based on the transmission line theory, influence factors of microwave absorbing ability for slab coat were analyzed and calculated. It was found that the parameter absorption rate could not effectively describe the different influence from material character, geometry dimension and microwave. As a solution, the matching property and absorption property needed to be discussed simultaneously. According to the new representation, matching property of coat depends only on the material character, whereas the absorbing ability resulted from the interaction between different interfaces within the sample. The influence of microwave frequency is reflected by interfere between different interfaces. Relatively, in the new representation, the influence from different factors was clear and intuition, which means the applicability of the new representation.
Effects of Substrate Temperature on the Properties of Silicon Nitride Films by PECVD
Authors: Li Chun Ya , Li Xi Feng , Chen Long Long , Shi Ji Feng , Zhang Jian Hua
Published: March 2013

Under different growth conditions, silicon nitride (SiNx) thin films were deposited successfully on Si(100) substrates and glass substrates by plasma enhanced chemical vapor deposition (PECVD). The thickness, refractive index and growth rate of the thin films were tested by ellipsometer. The surface morphologies of the thin films were investigated using atomic force microscope (AFM). The average transmittance in the visible region was over 90%.
Electrical Characterization and Microstructures of Bi3.3Tb0.6Ti3O12 and Bi3.3Tb0.6Ti2.97V0.03O12 Thin Films
Authors: Liu Rui Fang , Sun M.B. , Ding W.P. , Mei X.A.
Published: March 2013

Bi3.3Tb0.6Ti3O12(BTT), Bi3.3Tb0.6Ti2.97V0.03O12(BTTV), and pure Bi4Ti3O12 (BIT) 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 Tb doping into BIT also result in a remarkable improvement in ferroelectric property. The remanent polarization (Pr) and coercive field (Ec) of the BTT film were 25 μC/cm2 and 85 kV/cm, respectively. Furthermore, V substitution improves the Pr value of the BTVT film up to 35 μC/cm2, which is much larger than that of the BTT film.
Ferroelectric and Electrical Behavior of Bi4-xNdxTi3O12 Thin Films
Authors: Huang C.Q. , Liu X.B. , Mei X.A. , Liu J.
Published: March 2013

Nd2O3-doped bismuth titanate (Bi4-xNdxTi3O12: BNT) thin films with random oriention were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique, and the structures and ferroelectric properties of the films were investigated. XRD studies indicated that all of BNT films consisted of single phase of a bismuth-layered structure with well-developed rod-like grains. The remanent polarization ( Pr ) and coercive field (Ec) of the BNT Film with x=0.8 were 25μC/cm2 and 55KV/cm , respectively. After 3×1010 switching cycles, 15% degradation of Pr is observed in the film.
Structure and Optical Properties of Al1−xScxN Thin Films
Authors: Yang Jing , Cao Miao Miao , Li Yu Dong , Chen Yi Gang
Published: March 2013

In this study, c-axis oriented AlN and Al1−xScxN films have been successfully grown on Si (100) and quartz glass by DC magnetron reactive sputtering method. The XRD patterns show that the crystal structure of the Al1−xScxN films is (002) orientation. The grain size and band gap energy (Eg) of the Al1−xScxN films decrease as the Sc concentration increases. The frequency of the E2 (high) mode observed in the Al1−xScxN films shows higher red shift compared to that observed in AlN film and the peak shifts to the low wave number with the increasing of Sc concentration.
Effect of Hydrolysis Modifier on the Properties of ATO Films Prepared by Spin Coating
Authors: Galaviz-Pérez Jorge Alberto , Chen Fei , Shen Qiang , Vargas-García Jorge Roberto , Zhang Lian Meng
Published: March 2013

ATO thin films have been successfully prepared by the spin coating method using an ethanol solution of SnCl4∙5H2O and SbCl3 using acetylacetone as hydrolysis modifier. ATO films from 1 to 6 layers were prepared at 300 °C as densification temperature and within an annealing temperature ranging from 450 °C to 750 °C. Films exhibited the cassiterite crystalline phase and morphology consisted in nanoparticles of about 10 nm in diameter. Acetylacetone content as well the addition of water affected the particle size and morphology, decreasing particle size and the appearance of voids. Films prepared at an acetylacetone ratio of 4 with no addition of water exhibited an optical transparency above 90% from 380 to 800 nm while resistivity was 7.99 x10-3 Ω∙cm. The effect of the hydrolysis modifier on the electric properties, morphology, optical transparency and microstructure has been studied
Study on Inorganic Coating of Porous Nitride Radome
Authors: Liao Rong , Cheng Chuan Bing , Wang Chong Hai , Wang Hong Sheng , Wei Qi Hong
Published: March 2013

The surface of porous nitride radome became very compact by AlPO4-Si3N4-SiO2(n) coating treatment. Coating could immerse into the matrix about 20μm deep. This could also make material be moisture resistance for long time placement. Coating effectively healed the micro cracks on the matrix and combined with it by crossed occlusion, so the strength and the fracture toughness of material increased.
Mechanism of Annealing Treatment Effect on the Gasochromic Properties of WO3 Bulks and Films
Authors: Jin Xiao Bo , Wu Guang Ming , Gao Guo Hua , Feng Wei , Zhang Zeng Hai , Shen Jun
Published: March 2013

Nanostructural WO3 materials exhibit excellent gasochormism performance under the action of the hydrogen gas. In this paper, we study the mechanism of annealing treatment effect on the gasochromic properties both of the WO3 bulks and WO3 films. WO3 bulks were prepared from WO3 sol and dried under ambient pressure, which was previously synthesized via sol-gel method. The WO3 films were prepared using dip-coating method. UV-visible spectroscopy, Raman spectroscopy, Fourier transforms infrared spectroscopy (FT-IR) and X-ray diffraction spectra (XRD) were utilized to investigate components, structures and gasochromic properties. And we find that the mechanism of the thermal treatment on the gasochromic performance depends on H+ diffusion velocity which largely relies on the structural water content.
Study on Hole-Sealing Coating of Porous Silicon Nitride Surface
Authors: Wei Qi Hong , Wang Chong Hai , Li Ling , Wang Hong Sheng , Liu Jian , Liao Rong
Published: March 2013

Hole-sealing coating was fabricated on the porous silicon nitridesubstrate by sol-gel method, with Li2O-Al2O3-SiO2 as the basic materials and other additives were added. The morphology of the coating was tested by scanning electron microscope(SEM). The density,water absorption and porosity of porous silicon nitride before and after coating were tested by Archimedes method.The bending strength was tested by universal testing machine．The results indicated that the water absorption of porous silicon nitride was decreaced by 93.73% to 96.74%, the bending strength of porous silicon nitride was increaced by 8.21％ to 15.56％.
Preparation and Photocatalytic Activity of Shape- and Size-Controlled TiO2 Films on Silica Glass Slides
Authors: Chen Ru Fen , Jia Xin Xin , Meng Xiang Min
Published: March 2013

TiO2 films consisting of rod-like to sphere-like TiO2 particles on glass slides were synthesized by assembly technique. The results showed that the shape and size of TiO2 particles could be manipulated using different concentrations of polyethylene glycol 20000. By increasing of PEG, the shapes of the TiO2 particles transformed from rod-like to sphere-like, the size of TiO2 particles became gradually smaller. The size became bigger when an excess amount of PEG was added. With the adding of PEG，the amount of the TiO2 , the hydroxyl content, and the rutile phase content on the surface of TiO2 films increased, respectively. The photocatalytic activity of TiO2 films added PEG was higher than that of unadded samples.
The Effect of SiC Coating on the Joint of C/C and LAS
Authors: Zhu Huan Xia , Li Ke Zhi , Lu Jin Hua , Li He Jun
Published: March 2013

The SiC coating on C/C composites was prepared by CVD and pack-cementation method in this paper, then SiC coated C/C composites was jointed with LAS glass ceramic at 1423K for 30min and the pressure of 15 MPa. The structure and morphology of the SiC coating and as-received joints were analyzed by SEM and XRD; shear strength of joint was examined through the Instron universal testing tensile machine. The results show that the thickness of SiC coating prepared by CVD is about 30μm, while the thickness of SiC layer by pack-cementation is nearly 100μm, and the layer is easier to connect with LAS glass ceramic owing to the rough surface and wedge-shaped structure on the SiC coating; the shear strength of joint between SiC coating coated C/C and LAS by pack-cementation is greater than the joint of C/C- LAS with SiC coating prepared by CVD.
Ceramic Coating of TiC-TiB2 on 1Cr18Ni9Ti Substrate Achieved by Combustion Synthesis in High-Gravity Field
Authors: Zhao Zhong Min , Zhang Long , Song Yi Gang , Wang Min Quan
Published: March 2013

Based on fusion bonding of liquid TiC-TiB2ceramic film to stainless steel substrate of 1Cr18Ni9Ti, the ceramic coating on stainless steel substrate was achieved in graded composition by combusion synthesis in high-gravity field. XRD, FESEM and EDS results showed the ceramic coating was composed of a number of fine TiB2platelets, irregular TiC grains and a few of Cr metallic binder and the inclusions of Al2O3partilces, and physical and mechanical properties showed density, relative density, microhardness and fracture toughness of the ceramic coating were 4.25 g • cm-3, 98.2%, 24.6 GPa and 14.5 ± 3.5 MPa • m0.5, respectively. The joint of TiC-TiB2ceramic coating on stainless steel substrate consisted of 3-layer structures, i.e. the ceramic coating, the intermediate and stainless steel substrate, and within the intermediate of Fe-Cr-Ni-Ti metallic matrix Ti-Fe enriched carbides decreased gradually both in volume fraction and particle size from the ceramic coating to stainless steel substrate in the presence of atomic unidirectional diffusion of Ti and C, while some isolated α-Al2O3fine particles were also observed in the intermediate besides the presence of both some coarsened α-Al2O3inclusions nearby the ceramic coating and the barrier layers of Al2O3between the ceramic and the intermediate, so it is considered that the ceramic coating on stainless steel substrate is achieved partially by fusion bonding due to the poor incompatibilities between Al2O3inclusions and the intermediate, resulting in the moderate shear strength of 125 ± 35 MPa between the ceramic coating and stainless steel substrate.
Designing of Thermistor Digital Thermometer Based on Unbalanced Electric Bridge
Authors: Zhang Dan , Shi Ming Ji , Chen Lan Li , Ding Shu Juan
Published: March 2013

The temperature measure principle of unbalanced electric bridge is expounded by means of temperature characteristics of thermistor. A method to deal with nonlinear function is proposed. The experiment indicts that the thermistor digital thermometer based on unbalanced electric bridge is in accordance with the design request. Its circuit is simple and it has certain practical value.
Study on the Synthesis of Nano-Crystalline Mg2SiO4 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 forsterite-structure Mg2SiO4 was successfully synthesized by the aqueous sol-gel method using Si sols 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 scanning electron microscope (SEM), respectively. The results showed that the calcination process of gel consisted of a series of oxidation and combustion reactions, accompanied by significantly exothermal effects. Highly reactive nanosized Mg2SiO4 powders were successfully obtained at 850 °C with particle size of 60~80 nm.