bluuebunny/crossref_metadata_2025 huggingface dataset:
Real-Time Error Compensation Technique and Its Application on NC Machine Tools
Authors: Liu Guo Liang , Zhao H.T. , Turyagye G. , Ren Y.Q. , Yang Jian Guo , Chen Wen Zhe , He S.W.
Published: March 2009

This paper presents the method and process of the real-time error compensation (RTEC) on NC machine tools, which includes: identification and measurement of error components, separating and modeling of geometric-thermal error components, geometric-thermal volumetric error synthesis model, compensation control system, performance evaluation of error compensation by the body diagonal displacement measurement, and the industry application of real-time error compensation. The technique has been successfully applied to many different NC machine tools in the plants for practical production, and the machining accuracy of the NC machine tools is improved by an order of magnitude with low cost.
Research on Ultra-Precision Process of STAVAX ESR
Authors: Yuan Ju Long , Lou Fei Yan , Wang Zhi Wei , Chang M. , Du W.P. , Tao B.C.
Published: March 2009

STAVAX ESR（S-136）is a type of high stainless steel, used in precision mould widely . It has fine anticorrosion, polishing-alike, wearable，good process capacity and quench stability. To obtain the smooth surface of STAVAX ESR, the material removal mechanism in the paper is discussed. The experiment is processed on the ultra-precision plane polishing machine (Nanopoli-100). The experiment processes are as follows. Rough lapping and Ultra-precision lapping: the material of lapping pads is cast iron. #1000Al203 (10wt%) abrasive powders are used in
rough lapping. Finally, surface roughness is 62nm. In ultra-precision lapping, abrasive powders are for #4000Al203（10wt%）. Removal rate is 1nm with linear velocity 8.6m/min, pressure 3.65MPa. After 4000 rounds, surface roughness is 35nm.Ultra precision polishing: The super smooth surfaces of STAVAX ESR（S-136）with 5nm roughness have been obtained by adopting SiO2(> 30wt%) slurry and soft tin polisher in the experiment.
Overview on Measuring Methods of Bond Strength of Cladding Material
Authors: Yang Jun Ru , Li Zhao Qian , Huang Chuan Zhen
Published: March 2009

Bond strength is a key property to evaluate quality of cladding layer. According to the thickness of the cladding, surface cladding layer can be classified into two categories: thick and thin layer. The later is usually called thin film. Bond strength includes static and dynamic bond strength. As to thick cladding layer, main measuring methods of static bond strength are sticking extension method, interfacial indentation method, shearing method, fracture mechanics method. Contact fatigue method is the main measuring method of dynamic bond strength. As to thin film, main
measuring methods of static bond strength are extension method, scratching method, indentation method, scraping method, bulge blister method, laser spallation method and so on. The main measuring methods of dynamic bond strength are facing contact rolling method and ball contact rolling method. The paper made overview on all above methods.
Web Based Virtual Design of Dynamics of Roller Gear Cam System
Authors: Zhou Yi Qi , Tang Wei Xiao , Zhang H. , Shi B.C.
Published: March 2009

The remote virtual design system based on B/S framework is investigated in the paper. On reviewing the current virtual design system situation, the control system dynamics simulation is integrated into the virtual design system of roller gear cam mechanism. Simulink and Matlabserver are employed to realize the dynamics simulation for the system, and COM and VRML technologies are used to browse the virtual model on the network platform. The prototype system indicates that the system can serve as an effective tool for designing roller gear cam mechanism with the better properties of interactive dynamics performance design and expansion usage.
Partial Approximate Symmetry Detection of Geometric Model
Authors: Gao C.H. , Langbein F. , Marshall D. , Martin R. , Li Yan , Yang Z.
Published: March 2009

Engineering geometric models are often designed to have symmetries and other
regularities. In knowledge based reuse, creative design and design for mass customization, to have the information of such symmetries and other regularities from a geometric model is very useful. And this can make us understand more about the geometric model. In reverse engineering, B-rep models are created by fitting surfaces from point sets obtained by scanning an object using a 3D laser scanner. Each fitted surface is determined independently. The reverse engineered object can be improved by imposing these symmetries and other regularities on. This paper discusses the particular problem of finding partial approximate symmetries present in geometric model. A practical algorithm for finding partial approximate symmetries within a 3D B-rep model defined with planes, spheres, cylinders, cones and tori is presented. The experiment results show that the algorithm detects the symmetries expected and can do so reasonably.
Theoretical Study on Extended Master Model of Mould Feature
Authors: Zheng B. , Sun J.K. , Jiang Zhao Liang
Published: March 2009

In this paper, a concept of extended Master Model is presented, mould features are
classified and the master model of information hierarchy of mould is built. According to feature mapping theory, mapping categories of mould features are defined, mapping from mould features in various stage to cost feature field is implemented, which lays foundation for building cost information model of mould and implementation of cost oriented mould design.
Development of an Intelligent System for Tool Materials Selection in High Speed Machining
Authors: Liu Zhan Qiang , Peng Xiu Guang , Liu J.G.
Published: March 2009

Tool materials play one of the pivotal roles in the machining system. Tool materials must be carefully chosen in relation to the workpiece material to be machined, the tool life, the metal removal rate, the machining cost, and the required accuracy and finish. The advantages and decision-making processes of case-based reasoning (CBR) are described. The CBR system for tool material selection in high speed machining (HSM) is developed. The case expression and organization, searching, matching and constraint-based adaptation rules are presented. With combining the case-based reasoning strategy and constraint-based adaptation, the tool material can be properly selected on the basis of previously successful tool materials used in HSM operations, which is helpful to push the wide applications of HSM.
The Experiment Analysis and Numerical Simulation on Fracture of Complex-Shaped Part Drawing
Authors: Sun Zhen Zhong , Yang Yu Ying , Chen Yu Quan , Li J.Y. , Guo L.R. , Hang Q.B.
Published: March 2009

The fracture is primary drawback to stability of production in the drawing of complex-shaped parts. In the paper, the fracture of complex-shaped part drawing is investigated experimentally and numerically. A grid method is adopted to analyze the deformation character, deformation path, deformation degree and safety margin in risk region where is determined by numerical simulation and experiment. The magnitude of safety margin and the stability of production are greatly increased by optimizing the height of draw-bead and the blank size.
Research on Direct Laser Sintering of Ni-Alloy Powder and Microstructure Feature
Authors: Zhao J.F. , Li Y. , Zhang J.H.
Published: March 2009

The direct laser metal sintering experiments were carried out with nickel alloy powder material system. The melting–solidification approach was discussed. Microstructure and components of DLMS-process sample were analyzed. The incomplete liquid phase sintering is the main mechanism of the melting-solidification approach. In powder material system, the additive copper improves the wettability of melting material, and minimizes the balling phenomenon. The equiaxial dendrite and the dendrite are the primary crystal morphologies. The compositions of materials are
distributed uniformly.
Laser Driven Substructural Modification of Austenitic Stainless Steel
Authors: Zhou Ming , Zhu X.Q. , Dai Q.X. , Cai Lan
Published: March 2009

In this paper, the technique of high energy and short pulse duration laser impact is
adopted. The substructural transformation characteristics and mechanisms of the austenitic stainless steel, subjected to strain-rate of 106s-1 order and stress of 2.70GPa, are investigated. SEM observations, there exists regular arrangement of chapped and equiaxed subgrain regions within the original grains. The size of the subgrain ranges from 0.1 to 0.5um; Meanwhile, the compacted deformation twin bundles with about 1um width each twin have been examined in the regions treated. It indicates that the equiaxed subgrains, close to nanometer scale, had evolved in the surface of austenitic stainless steel, and they belong to dynamic rotational recrystallization; Although, twinning deformation is not a frequent phenomenon in terms of austenitic stainless steel at room temperature, it will play a significant role when austenitic stainless steels are submitted to high strain rate and stress. Additionally, X-ray diffraction reveals that the crystal lattice constant is up 1.12% compared to the normal one and no deformation-induced α-martensite and amorphous phase are spotted within the processed regions.
Crystallization of Fe40Ni40B16Si4 Amorphous Alloy
Authors: Janovszky Dóra , Sólyom Jenő , Roósz András , Daróczi Lajos
Published: March 2009

Fe40Ni40B16Si4 alloy was prepared by the melt spinning method with 50µm thickness. The crystallization of the amorphous alloy was analysed using a differential scanning calorimeter, X-ray diffraction method and a transmission electron microscope.
Magnetic and Structural Properties of Ferrimagnetic Bioceramics
Authors: Kis A.C. , Leventouri Th. , Thompson J.R.
Published: March 2009

Structure and magnetic properties of ferrimagnetic bioceramics in the system
{0.45(CaO, P2O5) ySiO2 xFe2O3 0.03Na2O}, x=0.05, 0.10, 0.15, 0.20, were studied by x-ray powder diffraction and magnetic measurements. Magnetite and calcium phosphate, crystallizing in the hexagonal and monoclinic crystal systems, are the major phases in the compounds. Phase development, crystal structure, and magnetic properties of the composites are determined by the specific starting composition of oxides and the heat-treatment temperature.
Stereological Characterisation of Steel Wide Strip Microstructures
Authors: Gácsi Zoltán , Csepeli Zsolt
Published: March 2009

The continuous development of steel products requires the detailed investigation of
relationships between the production technology, microstructure, and mechanical properties. This paper describes the detailed characterisation of normalising rolled and of thermomechanically rolled steel wide strip microstructures and presents the relationship between their microstructures and their mechanical properties. The morphology of the microstructures were characterised by using an image analyser. The most important measured stereological parameters were the area, perimeter,
length and breadth of the ferrite and pearlite cross-sections.
Analysis of Literature Models on Viscosity of Binary Liquid Metallic Alloys on the Example of the Cu-Ag System
Authors: Budai I. , Benkő Mária Z. , Kaptay György
Published: March 2009

The aim of this paper is to review all the existing literature models on the concentration dependence of the viscosity of binary liquid alloys and to check them against the measured viscosity values in the binary liquid Cu-Ag system at 1373K.
Comparing of the Processes of the Isothermal Phase Transformations of the Material Type 50 CrV 4 Using Different TTT Diagrams and Applying FEM Based Phase Elements
Authors: Dudás Zoltán
Published: March 2009

The application of the FEM based phase elements is very useful for evaluation of the
effects of TTT phase transformations diagrams. The comparison of the different TTT diagrams of the same type of the 50 CrV 4 steels shows that fine differences are possible to be evaluated and approximated by this simulation. Examples are presented for the use of the multiple regression calculation applying the data of the suitable TTT diagrams.
Dimensions of Lifetime Management
Authors: Lukács János
Published: March 2009

The lifetime management of different engineering appliances, structures and structure elements is one of the important technical-economic problems of nowadays. The problem is basically appeared in technical, economic and political dimensions and the solution can be imagined according to many approaches: microstructural approach, application of new design conceptions and operational approaches (conventional methods, fitness for purpose, structural integrity, integrity management, risk management). The methods, applied in the different approaches have basically two types: engineering and fracture mechanical methods. The time of operation, the frequency data of fractures and the fracture causing failure statistics of the engineering structures having great importance shows, that the significance of cyclic loadings, fatigue and fatigue crack propagation is emphasized in general. The sketched possibilities are shown by two examples in this paper. One of them is the system of lifetime management for cyclic loaded structures having cracks or crack like defects; the other is the building-up and purport of the integrated management system for hydrocarbon transporting pipelines.
Chaotic Phenomena in Fast Plastic Deformation (in the Case of Cutting)
Authors: Pálmai Zoltán
Published: March 2009

Technologies applied in machining metals are often characterised by highly localised shear strain, which can be regarded nearly as adiabatic, and which might lead to thermoplastic instability in certain cases. In cutting, similar incidents can be observed in the shear zone, in which γ=2–50, dγ/dt≈104 s-1, dT/dt=106 K/s, and under such extreme conditions chaotic phenomena may occur occasionally. Chip formation can be described by a two-dimensional model, where the variation of shear stress τ and temperature T in time are given by autonomous differential equations, while the material characteristics are determined by exponential constitutive functions. The solutions of equations can be classified by the coefficients of the characteristic equation of the Jacobian matrix. Two types of stable focuses and Hopf bifurcation can possibly occur, which corresponds to the two types of chips; continuous chip and segmental chip. The model should be broadened to describe the typical chaotic phenomena.
Nanocrystalline Soft Magnetic Cores in Applications
Authors: Juhász R. , Szabó S. , Kátai Z. , Bakos F. , Beke Dezső L.
Published: March 2009

Finemet type materials show extremely soft magnetic behavior with excellent and in
wide range on-demand variable macroscopic parameters [1]. Requirements for the most important magnetic parameters (e.g. permeability, coercitive force, saturation, loss) are determined by the targeted applications. We report results on the optimization of crystallization treatments and parameter tailoring by magnetic field induced anisotropy. As compared to the most widely used magnetic materials our samples have parameters of real measure of excellence.
Tribological Properties of Laser Processed Fe-Cr-C Alloys
Authors: Colaço Rogerio , Vilar Rui
Published: March 2009

A laser rapid-alloy-prototyping technique, was used to produce a number of alloys with compositions lying in the Fe-rich corner of the Fe-Cr-C system. These alloys were prepared in the form of thick coats deposited on a carbon steel by variable powder feed rate laser cladding. The microstructure of the alloys was analyzed by SEM and their mechanical properties were evaluated by microhardness tests, ball-cratering micro-scale abrasive wear tests and scratch tests. Although a poor correlation between the hardness of the alloys and their wear behavior was observed, the correlation between their wear resistance and the fab factor, measured from the scratch tests, is acceptably good. These results are discussed and analyzed on the basis of the microstructural characteristics of the alloys.
Synthesis of a Novel SAP with PS Foam
Authors: Li Li , Zhou Ninglin , Wei Shao Hua , Xu Bin , Qin Yufang , Shen Jian
Published: March 2009

A super-absorbent polymer (SAP) is synthesized with polystyrene foam (PSF) and sodium acrylate through inverse emulsion polymerization. The influence of experiment conditions such as solvent of PS, composition of comonomers, initiator and cross-linking agent on the absorption capacity of the resins are discussed. The maximum water absorption rate of the prepared SAP is about 1600g/g.
Determination of Friction and Wear of Engineering Polymers by Means of Large-Scale Specimen Testing
Authors: Samyn Pieter , de Baets Patrick
Published: March 2009

Although tribological tests on polymers are traditionally performed on small-scale
pin-on-disc or bloc-on-ring configurations, present sliding tests under high load provide more accurate de-sign data. For wear tests on large samples edge effects, stress concentrations and the moveability of wear debris into the contact zone are simulated close to practice. It is illustrated that friction is gene-rally lower compared to small-scale tests, while overload and deformation occur more frequently.
Research on Tribology of C/C Composites in Wet Conditions
Authors: Zhang Fu Kuan , Yuan Yi Dong , Zhou Wan Cheng
Published: March 2009

C/C composites have the phenomenon of the decrease of friction coefficient in wet
conditions, companied with the change of wear behavior. In this paper, the effect of
micro-tissue and density on the tribology behavior of C/C composites in wet conditions has been studied. The results indicate that all the above factors influence the tribology behavior of C/C composites at a different degree. It is believed that all the above factors change the ability of absorbing water by the C/C composites. The different degree of water absorption in turn changes the tribology mechanisms of C/C composites resulting in the change of tribology behavior of the C/C composites.
A Study on the Fracture Mechanism of Smart Composite under Thermal Shock Cycles Using AE Technique
Authors: Lee Jin Kyung , Park Young Chul , Lee Sang Ll
Published: March 2009

A smart material is used as spectacle frames and brassiere frames, and partly in medical supplies because of its shape memory effect. The smart composite can be used on the wing of an airplane instead of the existing aluminium to control crack propagation. In this study, the smart composite was fabricated by a hot press method. TiNi alloy as reinforcement and Al6061 as matrix were used, respectively. The mechanical properties of the smart composite under thermal shock cycles were evaluated. In addition, Acoustic Emission techniques were also used to clarify the
damage behavior of the smart composite under thermal shock cycles nondestructively.
A Study on Nanometer-Sized BaTiO3-Based Dielectric for Ni-MLCC with Y5V Specification
Authors: Ji Zhen , Xiao Zhigang , Wang Sen , Gu You Song , Zhou Cheng , Zhang Yue
Published: March 2009

In order to meet the demand on the miniaturization and manufacturing cost reduction of the multilayer ceramic capacitors we have developed a nano-BaTiO3-based non-reducible dielectric material through a soft chemical route. The particle size has been decreased down to the level of 30nm and the dielectric medium could be co-fired with Ni-electrodes under a N2+H2 reducing atmosphere. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and volume shrinkage have been employed to detect the sintering behavior and microstructure evolution including grain growth, pore formation and body densification. Dielectric measurements showed, after a sintering process at 1200°C for 2h, the dielectric constant was 8800, the dissipation factor was less than 2%, the insulation resistance was about 12~13exp Ω.cm, and the temperature coefficients of capacitance were less than 22% and -82% at -30°C and 85°C respectively. On the basis of the results it is anticipated that the material could be used for the Ni-MLCC with thin dielectric layers with a Y5V specification in the Electron Industries Association standard.
Anisotropic Properties of Grain Orientated Bismuth Titanate Ceramics by Spark Plasma Sintering
Authors: Hao Jun Jie , Wang Xiao Hui , Zhao Jian Ling , Li Long Tu
Published: March 2009

Textured bismuth titanate ceramics were successfully produced by spark plasma sintering, using plate-like Bi4Ti3O12 particles prepared by a molten salt method. The microstructure and electric properties of the samples were investigated. The results show that the textured Bi4Ti3O12 ceramics electric property is anisotropic in different direction, and spark plasma sintering is an effective sintering technology to get textured dense Bi4Ti3O12 ceramics at a low temperature.
Molten Salts Synthesis and Dielectric Properties of PMN-PT Ceramics
Authors: Zhao Shi Xi , Li Qiang , Song Feng Bing
Published: March 2009

Single perovskite phase PMN-PT powders had been synthesized using molten salts
method. The powders of PMN-PT synthesized by MSS had submicrometer particle size and high sinterability, which beneficial to an enhancement of the densification process and a decrease of the sintering temperatures. These advantages have an important bearing on the dielectric properties of these materials. The density of ceramics sintered at 1175°C was up to 98% of the theoretical density. These ceramics had excelled dielectric and piezoelectric properties.
Intermediate-Temperature Solid Oxide Fuel Cells with Y0.25Bi0.75O1.5-Ag Cathodes
Authors: Xu Xing Yan , Xia Chang Rong , Huang Shou Guo , Meng Guang Yao
Published: March 2009

Composites consisting of silver and yttria-stabilized bismuth oxide (YSB) were
fabricated and investigated as cathodes for intermediate-temperature solid oxide fuel cells (SOFCs) with thin electrolyte films of yttria-stabilized zirconia (YSZ). The films were deposited using spin coating with YSZ suspension. Comparison of YSB-Ag and conventional La0.8Sr0.2MnO3 (LSM) based cathodes showed that the YSB-Ag composite has better electrochemical performance; Interfacial polarization resistance of YSB-Ag cathode is 0.13 Ωcm2 at 750oC. Power density of the single cell with YSB-Ag cathode was about 535 mW/cm2 at 750oC, while that with LSM-Sm0.2Ce0.8O1.9 cathode was only 329 mW/cm2.
SPS Sintering of NaNbO3-KNbO3 Piezoelectric Ceramics
Authors: Zhang Bo Ping , Zhang Li Min , Li Jing Feng , Zhang Hai Long , Jin Song Zhe
Published: March 2009

Lead-free piezoelectric ceramics have received more attention due to the environmental protection of the earth. Niobate ceramics such as NaNbO3 and KNbO3 have been studied as promising Pb-free piezoelectric ceramics, but their sintering densification is fairly difficult. In the present study, Spark Plasma Sintering (SPS) was applied to the sintering of Na0.5K0.5NbO3 ceramics, whose powder was synthesized by the conventional oxide mixing method. No loss of sodium and
potassium were found in the SPS sintering process, by which the density of the K0.5Na0.5NbO3 solid solution ceramics was raised to 4.21g/cm3 (>93% of the theoretical density) at temperatures as low as 920°C. The crystal phase of the Na0.5K0.5NbO3 is an orthorhombic structure. The piezoelectric parameter (d33) of the K0.5Na0.5NbO3 ceramics reached 49 pC/N.
Composition Dependent Fatigue in Antiferroelectric PZST Ceramics Induced by Bipolar Electric Cycling
Authors: Zhou Long Jie , Rixecker Georg , Zimmermann André , Aldinger Fritz
Published: March 2009

Bipolar electric fatigue in antiferroelectrics of the lead zirconate titanate stannate ceramics family was investigated. Variations in strain hysteresis loops and damages in microstructure of the materials due to the electric cycling were analyzed. The materials showed symmetric or asymmetric suppression of strain hysteresis loop, normal or diffuse AFE-FE phase transition and intact or damaged microstructure after 5×10-7 cycles, indicating a strong composition dependent fatigue effect
and the corresponding mechanism. In general, the antiferroelectric materials exhibited much higher fatigue resistance than ferroelectric ceramics reported previously.
Synthesis and Growth Mechanism of Silicon Nitride Nanostructures
Authors: Xie Zhi Peng , Yang Wei You , Miao He Zhuo , Zhang Li Gong , An Li Nan
Published: March 2009

A new method to synthesize Si3N4 nanostructures via catalyst-assisted polymeric
precursor pyrolysis is present in this article. The as-prepared nanobelts are single crystals with a uniform thickness and width along the entire length, and contain no detectable defects such as dislocations or stacking faults. The thickness and width of Si3N4 nanobelts range from 40 to 60 nm and 600 to 1200 nm, respectively, and the lengths can be up to several millimeters. The growth directions of a-Si3N4 nanobelts are [101] and [100]. A solid-liquid-solid and gas-solid reaction/crystallization is proposed for the growth of S3N4 nonastructures.
Gelcasting of Alumina Ceramic in Presence of Water-Soluble Polymer
Authors: Ma Jing Tao , Xie Zhi Peng , Miao He Zhuo , Zhang Bao Qing , Lin Xu Ping
Published: March 2009

A new ceramic gelcasting system was developed in this paper. The rheological behavior of alumina suspension with an addition of polymer was examined. Particular attention is given to the flexural strength of green body prepared from gelcasting in the presence of polymer.
Controllable Forming Technology in Gelcasting
Authors: Yang Jin Long , Dai Chun Lei , Huang Yong
Published: March 2009

Controllable forming technology is one of the key problems for the industrial application of gelcasting. In order to solve this problem, various kinds of influence factors in gelcasting were investigated. Trace ions, ionic strength, pH, dispersant agent, premix, amount of initiator and catalyst, temperature, pressure, materials of container and inhibitor all have influence on solidification process of ceramic slurry. The forming process of gelcasting can be controlled effectively by adjusting these factors.
Biaxial Fracture Behavior of Polycrystalline Alumina
Authors: Tsukada Masayuki , Sato Eiichi , Kuribayashi Kazuhiko
Published: March 2009

Fracture behavior under multiaxial stress state of polycrystalline alumina was studied from the view point of an artificial crack propagation and fracture from a natural flaw. The former was studied by mixed-mode fracture toughness tests; asymmetric four-point bending and diametral compression techniques were carried out using precracked and notched specimens. The latter was studied by biaxial fracture tests in compression and torsion loading; multiaxial fracture statistics was applied to the measured fracture envelope. The ratio KIIC/KIC obtained from the biaxial tests was higher than that obtained by the mixed-mode fracture toughness tests. It revealed that the fracture from an artificial flaw does not simulate the fracture from a naturall flaw in polycrystalline ceramics.
Microstructure and Electrode Discharge Machining of TiN/Si3N4 Composites
Authors: Liu Chien Cheng , Huang Jow Lay
Published: March 2009

Conductive TiN/Si3N4 ceramic composites were processed by electrical discharge
machining (EDM) and their microstructure and conductivity investigated. A low electrical resistivity of 1.25×10-3Ω.cm was obtained in 40vol%TiN/Si3N4 composite. The whole process of tool electrode wear is evaluated by sinker-EDM. The machined surfaces of TiN/Si3N4 ceramic composites were examined by scanning electron microscopy (SEM) and profilometry to determine the surface finish. Micropores of 700µm in depth and 70µm in diameter were successfully machined in TiN/ Si3N4 composites by the micro-EDM method.
Microstructures and Microhardness of SNCed Medium Carbon Low Alloy Steels
Authors: Zhang Jun Bao , Liu Yue Lian , Zhao Xin Qing , Wu J. , Song Hong Wei , Xiong Tian Ying
Published: March 2009

Nanostructured layers were fabricated on the surface of 0.4C-1.0Cr and 1.0C-1.5Cr low alloy steels by using an ultrasonic particulate peening (USPP) technique. The microstructures and mechanical properties of the nanocrystallized layers were characterized by means of transmission electron microscopy, and nano-indentation test. Results showed that the average grain size in the surface nanocrystallized layer of 0.4C-1.0Cr and 1.0C-1.5Cr low alloy steel was about 5nm and 10nm, respectively. The nano-indentation hardnesses of the surface nanocrystallized layer were enhanced significantly and reach upwards of 8.0 GPa and 12.5 GPa, respectively.
Effect of Cr Content on Supercritical Water Corrosion of High Cr Alloys
Authors: Jang Jin Sung , Lee Yong Bok , Han Chang Hee , Yi Yong Sun , Hwang Seong Sik
Published: March 2009

High Cr alloys were corrosion tested in supercritical water and the oxide scale was
analyzed. Commercial grade two steel specimens; 9CrMoVNb steels, one 9CrMoVNbW steel, one 12Cr-MoVNbWCu steel and one 20Cr Fe-based O.D.S (Oxide Dispersion Strengthened) alloy specimen were investigated. Corrosion tests were conducted within non-deaerated pure supercritical water at 627, 550, and 500oC with 25 MPa. Corrosion rate was estimated by the weight change per
unit surface area and the oxide layer was analyzed using a grazing incidence X.R.D (x-ray diffractometer), S.E.M (scanning electron microscope) and T.E.M (transmission electron microscope) equipped with an E.D.S (energy dispersive spectroscope). Corrosion rates of the 9Cr steel specimens were observed to follow the parabolic growth rate law, while those of the specimens with a 12 per cent or higher Cr content showed significantly lower rates. Oxide scale on the 9Cr steel
specimen after a corrosion test in a supercritical water was found to consist of three distinctive layers. Through the cross-section T.E.M the outermost layer with about a 35 µm thickness after 200 hr at 627 oC was identified to be magnetite type Fe3O4, and about 25 µm thick intermediate layer was a Cr partitioned magnetite type (Fe,Cr)3O4. The outermost layer showed a coarse columnar structure, while the intermediate one revealed an agglomerate of tiny oxide particles (several tens nm in
diameter). The innermost layer next to the matrix phase was found to be the internally oxidized zone. Oxygen atoms seemed to have attacked along the grain boundaries and the lath boundaries and formed oxide CrO3 along the boundaries. Also a Cr depleted zone, and consequently a carbide-free zone, was observed along the interface between the internal oxidation zone and the matrix phase.
Functionally Graded Tungsten Carbide Cobalt Coatings Fabricated by Detonation Gun
Authors: Park S.Y. , Kim Moon Chul , Song Heung Sub , Park Chan Gyung
Published: March 2009

Fabrication of two different types of functionally graded tungsten carbide cobalt (WC-Co) coatings has been tried by using detonation gun to enhance both the hardness in the surface region and the toughness of the coating. Five layers with a continuous compositional change of 75 to 92 wt.% of WC were sprayed to obtain ‘layer-structured gradient’ coatings. Each layer was controlled to have
both minimum porosity and minimum phase decomposition of WC. New types of ‘continuously graded’ coatings were also fabricated to eliminate any obvious interfaces between layers by the ‘shot control method’ of detonation gun spraying. The wear resistance of these coatings was measured and compared to that of conventional WC-Co coatings by using dry sand abrasion tests under the
condition of 20kg load and 200rpm rotating wheel. Present functionally graded coatings revealed more improved wear resistance than that of conventional coatings.
Fabrication of W/Cu Functionally Gradient Materials by Multi-Billet Extrusion
Authors: Xie Jian Xin , Li Shi Bo , Chen Shu
Published: March 2009

W/Cu functionally gradient materials (FGMs) are fabricated by a novel
process—multi-billet extrusion (MBE). Different W/Cu superfine powders made by mechanical alloying (MA) are used to improve the sinterability of W/Cu compacts. Good quality of three-layer W/Cu extrudes are obtained after confirming the extrusion parameters and the type and the content of binder during extrusion process. The green products are pressureless sintered at the temperature
range of 1100-1300 oC for 1 h. W/Cu FGMs with relatively high density and high homogeneous microstructure are attained after sintering at 1200 oC for 1 h. The mechanisms for the enhance of sinterability and improvement of density of the mechanical alloyed (MAed) W-Cu powder products have been discussed. X-ray diffraction and scanning electron microscope are used to identify and observe phase constitution and microstructure, respectively.
Calculation of Thermal Stresses in Mo-Ti FGM with a Continuous Change of Composition
Authors: Zhang Lian Meng , Shen Qiang , Yang Zhong Min
Published: March 2009

In the present paper, a kind of Mo-Ti system functionally graded material with a continuous change of composition was formed via particle settling method at first, and then it was desified by hot-press under 1473K-30MPa-1h. Finally, by using an axisymmetric finite element method, the fabricated thermal stresses in a disk-shaped Mo-Ti FGM were calculated. The results showed that the thermal stresses changed continuously with the smooth variation of graded composition. The residual tensile stresses in the Mo-Ti FGM with a continuously changed composition were located in the medial region of graded layer and the radial compressive stresses distributed in the Mo- and Ti-rich sides. The calculated maximum residual tensile stresses in the Mo-Ti FGM were much lower than the bending strength of Mo-Ti alloys, which demonstrated that during fabrication no damages occurred in the Mo-Ti FGM with continuously graded composition.
TEM and TEM-EDX Analysis of Cross-Section of Anti-Reflective Thin Film and Glass Substrate
Authors: Yu Xin Gang , Ma Hong Wen , Zuo Yanbin , Zhao Hui Feng , Luo Wu Wen , Bi Wenrue , Wang Li
Published: March 2009

Two-layer antireflective films were prepared on Na-Mg-Ca-Si glass substrate by sol-gel process starting from metal alkoxides: Si(OC2H5)4, Ti(OC4H9)4. The transmittance of glass was increased obviously (>95%), the reflective index was reduced to 1.95 through visible light range. TEM observation showed that SiO2 film is compactly joined to TiO2 film and TiO2 film to the substrate. TEM-EDX analysis of the films, film-substrate interface and substrate revealed that with the increase of Ti content, the content of Mg，Ca and Si decreases, however, the content of Na increases. The diffuse of Na+ from the substrate to the film is negative diffusion.
Thermoelectric Properties on n-Type BixSb1-x /Bi2Te3 Graded Materials Containing Fullerite or Carbon Tube
Authors: Wu Xiao Feng , Xu Gui Ying , Niu Si-Tong , Ge Chang Chun
Published: March 2009

BixSb1-x and Bi2Te3 are typical thermoelectric materials used for lower temperature.
Samples of Graded materials containing different amount of fullerite or nanometer carbon tube and the were fabricated by hot pressing method. The relations about thermoelectric property, the addition of fullerite or nanometer carbon tube, and the microstructure were investigated in detail by normal measurement or analytical method.
Effect of Zn and Fe Concentrations on Structure and Optical Damage Resistances of Near Stoichiometric Zn:Fe:LiNbO3 Crystals
Authors: Li Hong Tao , Sun Zhi Jie , Ye Shaojian , Cai Wei , Zhao Lian Cheng
Published: March 2009

Zn,Fe co-doped near stoichiometric LiNbO3 crystals with variant Zn concentrations and with same Fe concentrations were grown by top-seeded-solution-growth (TSSG) method. The optical damage resistances of SLN crystals were studied by the method of transmittance facula distortion. The UV-Vis spectra showed that the grown undoping crystal had a composition very close to stoichiometric LiNbO3 crystal, and the absorption edges moved as the doping concentration changed. The optical damage experiments showed that, the crystal with 2mol% of Zn was with high
resistance to optical damage, and the optical damage resistance was improved evidently as the Zn concentration increased further.
Structure Characterizations and Growth of Bulk ZnSe Single Crystals by Zn(NH4)3Cl5 Transport
Authors: Li Huan Yong , Xu Ke Wei , Jie Wan Qi
Published: March 2009

Two chemical vapor transport methods with Zn(NH4)3Cl5 transport agent were developed to grow ZnSe bulk single crystals. Two kinds of Zn-rich ZnSe single crystals, conical crystal and flake crystal，were grown directly from untreated ZnSe polycrystals and two elements, respectively. The structure characters, purity and etch pit density were studied by rotating orientation XRD, PL spectrum and optical microscope. The contrastive investigation between two growth results indicated that the conical crystal was composed of (111) and (100) faces, and the flake crystal exhibited only (111) face. Moreover, the vicinal interface leaning to (111) face by the angle of 3.1° was the dominative growth face in vapor growth system, and growth occurs by layer-by-layer model. FWHM of RO-XRD pattern of ZnSe (111) face was 24sec for conical ZnSe crystal and 48s for ZnSe flake crystal. The results suggested that high-quality ZnSe crystals can be grown from the chemical vapor transport method with Zn(NH4)3Cl5 transport agent.
Study on Thermal Shock Resistance of Insulated Metal Substrate
Authors: Guo Liquan , Liu Yang , Ma Ju Sheng
Published: March 2009

Anodizing technique was applied to prepare insulated metal substrates (IMS) for BGA packaging. “Ideal” IMS used anodic film of aluminum as the insulating layer instead of epoxy, which led to higher thermal conductivity. But the thermal shock resistance of IMS is poor because of the great difference of thermal expansion coefficient between aluminum and its anodic film. In this study, different anodizing processes of aluminum were analyzed. The parameters, which can affect the thermal shock resistance of IMS, especially the surface temperature of Al substrate, were studied. The anodic film obtained with the optimized parameters of anodizing process had excellent performance, such as the resistivity was over 1013Ω·cm, the breakdown voltage was higher than 600V, and the most important thing was that it could resist thermal shocks between room temperature and 300°C. Then BGA packaging was successfully performed based on this IMS.
Effect of Initial Structure on Recrystallized Austenite Grain Size of Fe-32%Ni Alloy
Authors: Shon In Jin , Lee Seok Jae , Seo Young Seob , Lee Young-Kook , Jeong Yong Hwan , Choi Chong Sool
Published: March 2009

Recrystallization behaviors have been investigated with respect to two different kinds of the initial structures, original austenite and martensite, in an Fe-32%Ni alloy. The recrystallized austenite grain size from the martensite is much smaller than that from the original austenite, and decreases linearly with increasing the initial hardness, independent of the initial structure. The recrystallization sequences are different between the two structures: only one step due to recrystallization appears in hardness-temperature curve of the original austenite, whereas two steps
corresponding to reverse transformation of α’ to r’ and recrystallization are shown in that of the martensite.
Thermophysical Properties of Aluminum Infiltrated Silicon Carbide for Electronic Packaging
Authors: Liang J.F. , Yu J.K. , Quan Y.Q.
Published: March 2009

The effects of interfacial thickness and temperature on thermal conductivity and CTEs of Al/SiC packaging materials were investigated. The interfacial thermal conductivity and thickness have significant influence on the thermal conductivity of the Al/SiC packaging materials, while the SiC size has slight influence on that of the Al/SiC packaging materials. The experiment results of thermal conductivity are similar to Hassleman model and simulation results. Schapery model can be used to calculate the CTEs of composites when temperatures are lower(50~100°C) and Kerner model can be used when temperatures are higher(300~450°C). The CTEs of composites will increase more quickly than that by three models when temperatures are between 100°C and 300°C.
Preparation and Sintering Behavior of Au Conductor Pastes for LTCC Substrate
Authors: Wang Yan , Liu Yang , Ma Ju Sheng , Dong Zhaowen , Yin Mingli
Published: March 2009

Fine Au powders with spherical morphology and good dispersivity were produced. The average particle size is 1~2m. The influences of constituents on the rheology of organic vehicles were investigated by orthogonal design method. Consequently, the compatible Au thick film pastes for LTCC substrate have been prepared. SEM was carried out to study the sintering behaviors and microstructures of the buried pastes with LTCC substrate. These pastes have high electrical conductivity (less than 3m/sq.), reliable wire bond strength (greater than 9 grams, 25m Au wire) and fine line printability (as small as 80m). The via filling technology was also discussed in this paper.
Controlled Growth of III-V Compound Semiconductor Nano-Structures and Their Application in Quantum-Devices
Authors: Xu Bo , Wang Z.G. , Chen Y.H. , Jin P. , Ye X.L. , Liu Feng Qi
Published: March 2009

This paper reviews our work on controlled growth of self-assembled semiconductor
nanostructures, and their application in light-emission devices. High-power, long-life quantum dots (QD) lasers emitting at ~1 µm, red-emitting QD lasers, and long-wavelength QD lasers on GaAs substrates have successfully been achieved by optimizing the growth conditions of QDs.
Anti-Weak Localization of the Two Dimensional Electron Gas in Modulation-Doped AlxGa1-xN/GaN Single Quantum Well
Authors: Lu J. , Shen B. , Tang N.J. , Chen D.J. , Zheng Y.D.
Published: March 2009

The weak-localization of the two-dimensional electron gas (2DEG) in a
modulation-doped Al0.22Ga0.78N/GaN single quantum well has been investigated through the magnetoresistance measurements. The elastic scattering time τε, dephasing time τφ and spin-orbit(s-o) scattering time τso at various temperatures are obtained. The fitting parameters indicate that the inelastic scatterings to the 2DEG are mainly due to the piezoelectric field and the alloy disorder in the AlxGa1-xN barrier. When the second subband in the triangular quantum well at the heterointerface is occupied by the 2DEG, the anti-weak localization is observed clearly, which is due to the strong spin-orbit interaction. The spin-orbit effect dominates the quantum correction of the conductivity in the upper subband. The intersubband scattering becomes stronger with increasing temperature.
Blue and White Organic Light-Emitting Devices Using 2,5-Diphenyl -1, 4-Distyrylbenzene with Two Trans-Double Bonds as a Blue Emitting Layer
Authors: Cheng Gang , Xie Zengqi , Zhang Ying Fang , Ma Yuguang , Liu Shi Yong
Published: March 2009

A novel derivative of oligo(phenylenvinylene) (OPV), 2,5-diphenyl -1, 4-distyrylbenzene with two trans-double bonds (trans-DPDSB), is used as a blue emitting material in blue and white organic light-emitting devices (OLEDs). Blue devices with a configuration of indium-tin oxide (ITO)/N,N´-diphenyl-N,N´-bis(1-naphthyl)-(1,1´-biphenyl)-4,4´-diamine (NPB)/ trans-DPDSB / tris (8-hydroxyquinoline) aluminum (Alq3)/LiF/Al are constructed, where NPB, Alq3 and trans-DPDSB are used as hole-transporting, electron-transporting and light-emitting layers, respectively. The color of emission is changed from blue-green to pure blue when the trans-DPDSB layer is thicker. By inserting an ultrathin 5,6,11,12-tetraphenylnaphthacene (rubrene) yellow light-emitting layer between the Alq3 and trans-DPDSB layers, white OLEDs are obtained. The maximum efficiency and luminance of the blue and white devices are 1.2, 3.0 cd/A, and 1400, 7000 cd/m2, respectively.
Synthesis and Electrochemical Properties of Nonstoichiometric Spinel Phase (Li1.02Mn1.90Y0.02O4-yF0.08) for Lithium Ion Battery
Authors: Feng Chuan Qi , Zhang Keli , Sun Jutang
Published: March 2009

A nonstoichiometric spinel phase (Li1.02Mn1.90Y0.02O4-yF0.08) was synthesized using natural polymer net method. It was characterized by XRD and XPS. The particle size and shape of the expected compounds were observed by Transmission Electron Microscopy technique. The composition of new spinel phase was checked by ICP. The electrochemical properties of the new spinel phase (Li1.02Mn1.90Y0.02O4-yF0.08) were also investigated. The results showed that the Li1.02Mn1.90Y0.02O4-yF0.08 behaved excellent recharge ability to compare with stoichiometric LiMn2O4. The initial discharge capacity of the battery was 128.5 mAh/g when current density was 1 mA·cm-2 over voltage range of 4.4 to 3.0V. The discharge capacity could retain about 96% after 100 cycles when metallic lithium was anode. The outstanding electrochemical properties of Li1.02Mn1.90Y0.02O4-yF0.08 make it possible as a promising cathode material. The novel synthesis
method provides a simple and effective route for inorganic material synthesis.
Improving the Performance of Organic Light-Emitting Devices by Adding the Starburst Amine as Buffer Layer
Authors: Yang Hui Shan , Chen Shu Fen , Wu Zhi Jun , Zhao Yi , Hou Jingying , Liu Shi Yong
Published: March 2009

We have fabricated an organic light-emitting devices with high efficiency and brightness utilizing thick layer of a starburst amine compound 4,4’, 4’’-tris{N,-(3-methylphenyl)-Nphenylamin} triphenylamine (m-MTDATA) as hole injection buffer layer. The brightness and the current efficiency were comparatively improved compared with those of the device without the buffer layer. The device with 10nm m-MTDATA act as buffer layer has max brightness was 18590cd/m2 at 17 V, and the highest luminous efficiency was achieved 4.30cd/A, at 7V, which is nearly three times than that of the device without it.
Simulation of the MOCVD Reactor for ZnO Growth
Authors: Liu S.M. , Gu Shu Lin , Qin Feng , Zhu Su Min , Ye Jian Dong , Liu W. , Zhou X. , Zhang R. , Shi Y. , Zheng Y.D.
Published: March 2009

In this paper we have characterized the performance of a vertical metalorganic chemical vapor deposition (MOCVD) reactor used for deposition of ZnO thin films. The equations of the mathematical model are solved numerically using a control-volume-based finite difference method. A two-dimensional model is put forward to study the dependence of the growth rate on the inlet flow rate and susceptor temperature. The mass-fraction distribution of the reactants has been studied as a function of the position above the substrate, which shows that gas phase pre-reaction in our reactor is well confined. The simulation results are useful for the practical growth of ZnO.
Surface Age-Hardened High Speed Steel with High Co Content Formed on Undecarburized Carbon Steel
Authors: Zhang Yan Mei , Liu Yan Ping , Li Zhong Hou , Xu Zhong
Published: March 2009

Tungsten, molybdenum and cobalt were co-diffused into the surface of undecarburized 45 steel at 1150 °C for 6 hours by a double glow plasma surface alloying technique. A Fe-W-Mo-Co type gradient surface alloyed layer with very low carbon content was formed. Thickness of the surface alloyed layer is 225.2μm. Concentrations of alloying elements Co, W and Mo in the alloyed layer are mostly ranged from 21 to 14 wt.%, 12 to 6 wt.% and 7 to 5 wt.%, respectively. The concentrations of alloying elements basically meet the requirements of W11Mo7Co23 type age-hardened high speed steel. The alloyed samples were solution heat treated, ageing and high-temperature tempering. The results show that the surface alloyed layer formed on 45 steel exhibits very strong age-hardening property and anti-temper softening ability as the metallurgical age-hardened high speed steel, the surface age-hardened high speed steel on ingot and decarburized carbon steel.
Polarized Photoluminescence and Temperature-Dependent Photoluminescence Study of InAs Quantum Wires on InP (001)
Authors: Lei W. , Chen Y.H. , Wang Y.L. , Ye X.L. , Jin P. , Xu Bo , Zeng Yi Ping , Wang Z.G.
Published: March 2009

InAs quantum wires (QWRs) have been fabricated on the InP(001), which has been evidenced by TEM and polarized photoluminescence measurements (PPL). The monlayer-splitting peaks (MSPs) in the PL spectrum of InAs QWRs can be clearly observed at low temperature measurements. Supposing a peak-shift of MSP identical to that of bulk material, we obtain the thermal activation energies of up to 5 MSPs. The smaller thermal activation energies for the MSPs of higher energy lead to the fast red-shift of PL peak as a whole.