bluuebunny/crossref_metadata_2025 huggingface dataset:
The Impact of Export on China's Labor Standards: Empirical Analysis Based on Vector Auto-Regression Model
Authors: Wang Bo
Published: July 2011

This paper focuses on the impact of export on China's labor standards through empirical analysis. After building a stable vector auto-regression model, it uses the changing rate of the value of export as the index of export, and the growth rate of worker’s real wages as the index of labor standards. The result of estimation indicates that export has significant positive impact on China’s labor standards. The estimation of vector error correct model, the result of impulse responses and variance decompositions and the Granger causality test confirms that. The result of empirical analysis finds no evidence of the race-to-the-bottom of labor standards in China.
Research on the Parameter Optimization of Certain Complex Structure
Authors: Zhang Bao Cheng , Zhao Peng Fei , Li Peng
Published: July 2011

Using the method of the parameter study, some important dimensions of the cylinder head of an internal-combustion engine are analyzed. Under the mechanical load, the variational rules of the Von Mises maximum stress on cylinder head are obtained, which are influenced by the thickness of the floor plate, head plate, jobbing sheet, standing partition board, and side plate of inlet port and exhaust port. A hypothesis is verified that there is an ideal matching point among those above-mentioned main parameters. The quantificational proportion relations, between these key structural parameters and Von-Mises maximum stress of cylinder head, can provide a good help for the cylinder head’s structural design.
Tree Inferior Strong MVD for XML Document
Authors: Yin Li Feng , Jin Hua , Tian Hong
Published: July 2011

Data constraints are the basis of the database normalization, the introduction of XML documents with incomplete information, data constraints need to be re-defined. The precise definition of the tree inferior strong multi-valued dependency for XML documents(XTISMVD) was proposed, which was based on the tree structure and subtree information equivalent. Judging condition of XTISMVD was studied. By instance this paper shows that the existence of XTISMVD produces redundancies and update anomalies, moving or adding nodes for XML Schema can reduce redundancies.
Inference Rules for XML Strong MVD and XML Weak MVD
Authors: Yin Li Feng , Jin Hua , Tian Hong
Published: July 2011

For solving logical implication problem in the presence of XML strong multi-valued dependency(denoted as XSMVD) and XML weak multi-valued dependency(denoted as XWMVD) under incomplete information circumstances, the inference rules of XSMVD and XWMVD based on XML Schema were discussed. The concepts of XML Schema and incomplete XML document tree according with XML Schema were formalized. Based on the concepts of sub-tree information equivalence and sub-tree information consistent, the definitions of XSMVD and XWMVD were given and their nature was studied. When XSMVD and XWMVD exist at the same time in XML Schema, their inference rules were presented and their soundness was proved. The production in this work lays the foundation for normalization of XML Schema existing XSMVD and XWMVD at the same time under incomplete information circumstances.
Study on Temperature Effect in Micro-Cutting Process
Authors: Cao Zi Yang , Li Hua
Published: July 2011

A coupled thermo-mechanical model is used to simulate two-dimensional orthogonal cutting process based on simulation model of micro-cutting. The temperature effect in micro-cutting process is studied deeply through FEM combined with micro-cutting experiments. The results indicate that cutting temperature decreases at the tool-chip interface with reduction in uncut chip thickness at high cutting speed and large uncut chip thickness. The temperature drop tends to have a hardening effect on the material strength, which in turn causes an increase in the specific cutting energy.
A Theoretical Investigation on the Adsorption of CH4 onto the Surfaces of BaZrO3
Authors: Gao Zi Shu , Su Yi Guo , Lv Li , Wang Shu Wei , Han Hui , Wang Xiao Jing
Published: July 2011

In this paper, a density functional theory based on the first-principles was employed to evaluate the adsorption of CH4onto the surfaces of BaZrO3catalysts. The absorption mechanism was derived by population and electronic states analysis on the basis of the electronic and surface structure calculations for BaZrO3. The (001) surface was calculated to be the adsorption surface for CH4owing to its high stability. Comparing to that for CH4absorbed on (001) surfaces, the frontier energy state was found to the key factor in controlling the adsorption behavior, which is mainly contributed by oxygen and Zr ions of the B-site. The most favorite adsorption site for CH4was located at B-sites of BaZrO3, where the A-site ions would adjust the charge of B-site ions and moreover affect the CH4adsorption. The results reported in this work may provide the fundamental understanding about the absorption of CH4inflammation catalysts with high-activity and high-stability.
Research on Information Security Scheme Decision-Making of Internet Banking
Authors: Wu Pu Feng , Liu Qi , Wu Pu Sheng
Published: July 2011

Based on information security single item estimation and good enough security theory, decision-making of Internet banking security control proposal is researched in this paper. Internet banking security control decision-making should be executed through asset single item estimation and whole integration estimation this two layers separately. Substitutive of security proposal is discussed, which show that three steps of integration estimation should be cost option, technology feasibility option and security scheme merit rating. On the basis of cost option, technology feasibility option of security choice scheme is executed based on P2DR security theory and optimization option of security scheme is realized using fuzzy comprehensive evaluation model of improved layer analysis method.
Impact of Cavity Aspect Ratio on Natural Convection Heat Loss of a Solar Receiver for High-Temperature Dish System
Authors: Wu Shuang Ying , Xiao Lan , Li You Rong
Published: July 2011

A 3-D numerical study has been carried out to uncover the influence of cavity aspect ratio on natural convection heat loss of a solar receiver for high-temperature dish system, accounting for air property variation with temperature. Temperature and velocity contours as well as the variation of the natural convection heat loss with the cavity aspect ratio have been well presented and discussed. It is revealed that the expansion of convection zone together with the augmentation of velocity magnitude result in the increment of natural convection heat loss with decreasing aspect ratio, i.e., with shallower cavity, especially when the cavity aspect ratio larger than 1. Therefore, the solar receiver with much too shallow cavity should be avoided in design.
The Numerical Simulation of Exact Euler Load about Stability of Compressed Bar Based on Matlab
Authors: Jiang Jiu Hong , Zhu Ruo Yan
Published: July 2011

The relationship between the critical load and maxiumum deflection is established by applying numerical method to solve the curvature exact differential eqation of the buckled bar which fixed at base side and free at the upper side, the numerical values show that the critical load calculated through the approximate Eular formula is rather precise in a slight bent form. The numerical values give the stability stress and strength stress which can help to understand the stability calculation and strength calculation is completely difference.
An Object Tracking Method Based on the Coordinate-Locating of SIFT Algorithm
Authors: Zhou Shang Bo , Kang Kai
Published: July 2011

The SIFT (scale invariant feature transform) algorithm has been successfully used in the image matching field. In this paper, a simplified SIFT algorithm is designed. The number of layers in the Gaussian pyramid is reduced. When it is comparing the keypoints, it uses an outspreading method. The new method can reduce the comparison time and matching time. Although the new algorithm (C-SIFT algorithm) has less matching accuracy than the SIFT algorithm, it adopts a distortion detection method to abandon the wrong matching. Then it uses the coordinate displacement to determine the tracking position. Experimental results show that C-SIFT algorithm can perform steadily and timely.
The Research on Reordering Rule of Chinese-Mongolian Statistical Machine Translation
Authors: Wang Si Ri Gu Leng , Si Qin Tu , Nasun Urtu
Published: July 2011

There are a lot of word order errors that occur in the Chinese-Mongolian statistical machine translation system, so we proposed Chinese sentence reordering method based on the Mongolian word order. In this paper we first introduce the form and the tagset of reordering rules. We mainly introduce the reordering rules related to the verb phrase, prepositional phrase and subject-predicate phrase. Finally, we give out the experimental results. It is proved by experiment that the performance of the Chinese-Mongolian machine translation system can be improved using these reordering rules.
The Role of Bayonet Tube on Heat and Mass Transfer Characteristics of Capillary Porous Wick Evaporator Based on AMTEC
Authors: Wu Shuang Ying , Cao Bao Xi , Xiao Lan , Li You Rong
Published: July 2011

An axial symmetric 2-D invariable temperature phase change interface model of capillary porous wick evaporator with bayonet tube for alkali metal thermal-to-electric converter (AMTEC) was established to simulate flow and heat transfer characteristics in capillary porous wick and liquid channel by solving the mass and heat transport controlling equations. The effects of length, radius and thermal resistance of the bayonet tube on the distributions of pressure, velocity and temperature in capillary porous wick and liquid channel were analyzed. The results show that the performance of evaporator can be improved by inserting a bayonet tube into the liquid channel, including better averaging function of temperature, reduction in the peak temperature on the inner surface of capillary porous wick, and better adaptability in working environment. However, bayonet tube parameters should be carefully chosen depending on specific working conditions.
Model and Algorithm for Multi-Commodity Logistics Network Design Considering Service Level Constraint
Authors: Qin Jin , Ni Ling Lin , Zhao Xiao Bo
Published: July 2011

In the logistics network design, the decision-maker should not only select proper places to save commodities, but also determine the quantity of commodities saving in each place. This paper assumed the demands are stochastic and satisfy a normal distribution, and proposed a new optimization model which simultaneously described the inventory decision and the facility location decision. A combined algorithm based on the simulated annealing algorithm is used to solve and analysis the numerical example. Numerical application denotes the model and the algorithm operate rapidly and the results are rational, so it provides scientific guidance for the multi-commodity logistics network design problem.
Boiler Conceptual Design Based on RBR and CBR
Authors: Zhou Yi , Zhong Wei
Published: July 2011

Boiler is one of the key industrial equipment in the field of modern manufacture. Rule-base reasoning (RBR) and case-base reasoning (CBR) are first applied to the boiler conceptual design. The RBR is adopted to perform like a “sieve” for the acquisition of the candidate structure modules. Then the CBR process is adopted for the structure module modification and case retain. The case retain process gives the system self-enrich function which will improve the design ability of the system with the continuous use of the system.
Voltage Distribution Studies in Polluted ZnO Arrester Using the FEMLAB
Authors: Tighilt Ferhat
Published: July 2011

The voltage and electric field distribution in an arrester are very important for its long operation 15 kV with and without pollution. In order to clarify the influence of pollution severity conditions on metal oxide surge arrester, the finite element method (FEM) compilation of the voltage distribution in the ZnO column varistors under different pollution layer conductivity (200 μS, 70μS, 20μS) and clean was employed using the FEMLAB package.
Microstructure and Characteristics of Interfacial Region in Soldering Joint of ZA Alloy
Authors: Liu Xiu Zhong , Liu Xing Hong , Yang Min
Published: July 2011

Analytical instruments such as optical microscope, SEM and TEM are employed to investigate and analyze the microstructure and characteristics of soldering joint interfacial region. The results indicated that interactive crystallization exists in part of the interfacial region by using a newly developed kind of soldering filler metal. The composition of the interfacial region is complex such that both solid solution of Cd,Sn,Zn and small amounts of fine grained compounds of Mg2Sn,MgZn exist. Solid solution can improve the strength and plasticity, and small amounts of fine-grained compounds can strengthen the matrix which is beneficial for improving the bonding strength. However, successive laminate structure of intermetallic compounds will result in embitterment and deteriorate the properties of the joint.
Some Research about Technology of Disaster Tolerance for Data Center
Authors: Meng Xue Jun
Published: July 2011

Along with Development of digital campus, much key application system run on base of digital campus, usability of application system, integrality and confidentiality of application data arouse much recognition of university gradually. The paper gives introduction and analyzing from some key indexes, technology frame etc. and offer reference about construct of Disaster Tolerance system.
Design and Development of a New Automated and High Speed Cap Sealing System
Authors: Li Zheng Jeremy
Published: July 2011

Plastic welding is a technical process of welding plastic component together and it is one of the primary processes of joining plastics. There are several types of techniques in the plastic welding including hot gas welding, extrusion welding, contact welding, hot plate welding, injection welding, and friction welding, To increase the plastic welding speed and sealing capacity, this research introduces a new automated and high speed cap sealing system applied to cartridge filled with gas product. The computer-aided modeling analysis and prototype testing show that this automated and high speed welding system has high production rate, good sealing quality, reliable function, and cost-effective manufacturing process.
Convergence Analysis for Cubic Serendipity Finite Elements with Thirty-Two Degrees of Freedom
Authors: Liu Jing Hong , Huo Xiao Cheng
Published: July 2011

In this paper, we consider the Poisson problem with homogeneous Dirichlet boundary conditions on the bounded open domain and analyze convergence phenomena that appear by using cubic serendipity block elements with thirty-two degrees of freedom. By means of the standard Legendre polynomial technique, we derive an error estimate, which is not superconvergent and shows this serendipity element has not pointwise supercloseness properties.
A Prediction Based Data Aggregation Scheme in Wireless Sensor Networks
Authors: Li Guo Rui , Wang Ying
Published: July 2011

It is very important to minimize the amount of data transmission in wireless sensor networks so that the average sensor lifetime and the overall bandwidth utilization can be improved. In this paper, we propose a prediction based data aggregation scheme which takes advantage of temporal data correlation among sensors to monitor continuously changed environmental conditions. A seasonal time series model is built up to predict the sensed values of ordinary sensors according to the collected historical data. The experiment results show that our proposed scheme can provide considerable aggregation ratio while maintaining a low prediction error rate.
NN-Based Block Adaptive Backstepping Control of Induction Motor
Authors: Li Hai Yan , Hu Yun An
Published: July 2011

Based on the model of induction motors in field-oriented coordinates, a block adaptive backstepping method is used to design a controller for induction motor. The control law and parameter updating law are derived using Lyapunov theory, which guarantees the stability of the whole system. The proposed approach can track the rotor speed and flux reference signals under parameter and load uncertainties. Simulation results show the effectiveness of the proposed approach.
Software Design of Aircraft Electrical Load Management Center Based on μC/OS-II
Authors: Wu Jian Jun , Wan Wei , Zhao Da Hai
Published: July 2011

This paper introduces that embedded real time operating system μC/OS-II is applied in software design of aircraft electrical load management center. Firstly, the μC/OS-II and its running on ARM are briefly presented. Then the method of two system running modes is given in details. And the tasks assignment, priority allocation and communication between tasks under both two modes are also provided. Results show that multitask schedule managements of real-time system has solved the problem of poor real-time in a single task system. And the reliability of the system has been greatly improved.
Modeling of Stator Based on VRM(Virtual Reality Machining) in Toroidal Planet Gear Driving
Authors: Liu Chun Xia , Li Ping , Li Xin
Published: July 2011

The paper will introduce the processsing principle of the stator(the major parts of the toroidal planet gear driving ).then taking pro /e as tool ,setablishing the full –scale process modeling of the stator by the new method –VRM .
On-Orbit Servicing Task Allocation for Spacecrafts Using Discrete Particle Swarm Optimization Algorithm
Authors: Zhang Qi Xin , Sun Fu Chun , Ye Wen , Chen Jie
Published: July 2011

The on-orbit servicing task allocation is very important to improve the cooperative work ratio of the on-orbit servicing spacecraft. A discrete particle swarm optimization (DPSO) algorithm is put forward for on-orbit servicing spacecraft cooperative task allocation problems. A new code of particles and new update strategy for the position and speed of particles are applied. By analyzing the critical index factors which contain target spacecraft value, servicing spacecraft attrition and energy-time consumption, on-orbit spacecraft task allocation model is formulated. The simulation results show that the DPSO algorithm has fast convergence, optimization capability, and can solve the on-orbit servicing spacecraft cooperative task allocation effectively.
An Experimental Study for Crystallization Characteristics of Nd-Based Alloy
Authors: Yang Feng , Gao Zhi Hua , Wang Di , Liu Yang
Published: July 2011

The bulk metallic glass has received much attention from scientist and engineer. In this paper, we fabricated metallic glass of Nd-based and carried out experimental research. This kind of metallic glass has shown a distinct glass transition and stable super-cooled liquid region. At the same time, we find the paramagnetic performance of Nd-based metallic glass is different from other hard magnetic alloys at ordinary temperature. The DSC experiment indicate that the glass transition temperature increase with the heating temperature.
Research on the Development of Innovative Talent Based on Reform of Experimental Teaching
Authors: Qian Su Xiang , Xu Ju Wu , Li Ji Wu
Published: July 2011

Considering present situation of scientific and technological development and also employment, this paper stated the significance and urgency to cultivate creative talents. Totally six innovative projects were brought forward on account of the existing problems of experimental teaching in universities, including building up creative experimental programs, combining employment and the electronic designing competition, strengthening the development of lab, enhancing teachers’ capacity of experimental teaching, providing Technical training and relative service to society, etc. Anyhow, some teaching reforms have been under implementation, and improved with good effect.
Analysis of Affecting Factors and Countermeasures of Innovative Education in Military Academy
Authors: Hang Xu , Zhou Ming Qiu
Published: July 2011

This article analyses the education concept, teaching mode, education management mechanism and education quality evaluation system that aim at the traditional education in military academy, points out the issues that need to solved in view of the innovative education systems project., and gives concrete proposals and methods for solving questions.
The Education of Reform and Teaching Undergraduate Research in Biochemistry
Authors: Huang Yao Jiang , Zhou Yi Jun , Feng Jin Chao , Xue Da Yuan , Zhu Yong
Published: July 2011

Undergraduate laboratory course is the disconnection between a series of 3-hour miniaturized experiments at Minzu University. Here, we describe a new approach to teaching undergrad­uate research, inquiry and problem solving in a semester-long biochemistry experience. The program centers on topics were selected to study purification and characterization of major classes of biomolecules (such as SOD) within a guided research experience. Undergraduates are allowed to work independently, they make many choices throughout the program. Skills, motivation, and attitudes were assessed before and after the program. This approach is cost effective, is productive, and supports diversity. Undergraduate s achieved high levels of critical biochemical laboratory skills and critical thinking while increasing their confidence and it is beneficial regardless of the next phase for the students.
Study on the Auditing Problems of the Private Universities in China and its Internal Audit Improvement Policy
Authors: Li Tie Qun
Published: July 2011

From the view of the current reality, many internal audit issues of the private colleges are very prominent, which affects the development of private universities. Therefore, it is very important to study status of internal audit in College, to explore measures to strengthen the internal audit college education, to optimize the allocation of resources and improve the effectiveness of university education. The essay based on the analysis of the internal audit function of private colleges, try to find the internal audit problem of the private college and provide the relevant suggestions.
Performance Compensation of Networked Control Systems with Network Delay
Authors: Wang Jie , Gao Song , Yang Yong
Published: July 2011

The networked control system typically introduces network delay that have not been considered at the design stage. As a consequence, the system performance is degraded with respect to the expected response. This thesis introduces a methodology to apply external gain assist networked control systems. The proposed methodology uses externalgain to modify the controller output with respect to the current network traffic conditions in order to enable an existing controller for networked control systems and compensate the performance degradetion induced by network delay. This methodology can change existing traditional controller directly to network controller and not modify the original control algorithms.
Process Composition with Shared Resources
Authors: Guo Yu Bin , Zhang Min
Published: July 2011

Processes are well defined sequences of computational steps executed in a coordinated manner that make application logic of an information system explicit. Process composition with shared resource is defined and analyzed in this paper. Conditions of structural soundness of composited process and conditions of property preserving of sub-process are presented.
Inhibitory Effect of Tetrandrine on the Proliferation of Human Dermal Fibroblasts Derived from Hypertrophic Scars
Authors: Liu De Wu , Hu Xiang , Liu De Ming , Zou Ping
Published: July 2011

Tetrandrine can inhibit the proliferation and collagen synthesis of fibroblasts in lung and liver tissue confirmed by a series of clinical research. In this chapter, we investigated the effect of Tetrandrine on the proliferation of human dermal fibroblasts derived from hypertrophic scars. The dermal fibroblasts were isolated from human hypertrophic scar tissues and cultured in vitro. Tetrandrine with different concentration were added to culture medium respectively. The proliferative activities were determined. The result show that when the concentration of added Tetrandrine increased from 5μg/ml to 80μg/ml, the proliferative activities of cultured dermal fibroblasts were decreased gradually in dose-dependent manner. It conclusions that Tetrandrine can obviously inhibit the proliferation of human dermal fibroblasts derived from hypertrophic scars.
Construction Method to the Extension Model of Influence Diagrams
Authors: Peng Qing Song
Published: July 2011

Influence diagram is a kind of graphical model that can represent both the probabilistic relationship between variables and can easy to make decisions. Extension model of Influence Diagrams is reviewed in this paper and the construction method of this new model is investigated.
Size and Dimension Dependent Vacancy Formation Energy of Nanosolids
Authors: Xiong Shi Yun , Qi Wei Hong , Huang Bai Yun , Wang Ming Pu
Published: July 2011

A model for size dependent vacancy formation energy of nanosolids (nanoparticles, nanowires and nanofilms) has been developed by the consideration of their surface free energy. It is found that the vacancy formation energy of nanosolids decreases with the decrease of size. The relative variation of vacancy formation energy of nanoparticles, nanowires and nanofilms to bulk value at specified size follows 3:2:1. Furthermore, vacancy formation energy of nanosolids changes linearly with the reciprocal of size. The present results agree well with the predictions of BOLS and ECN theory.
Comparison of Three Methods of MOM, MLFMM and PO/MOM for Simulation of Variable Wall Thickness Radome
Authors: Zhang Lie , Zhang Juan , Du Peng Fei , Li Zuo Jun , Yue Zhu Feng
Published: July 2011

a Design Concept of Piecewise Variable Wall Thickness of Radome Is Proposed to Simulate the Radome which Has Variable Wall. the Paper Calculates the Far Field of a Medium-Size Radome in the Case of Piecewise Variable Thickness by Three Methods as Follows: Method of Moment (MOM), Multilevel Fast Multipole Method (MLFMM) and Physical Optics& the Method of Moments (PO/MOM) Respectively. after Comparing the Results, we Find that the PO/MOM Method Have the Superiority in Simulation of Radome’s Electromagnetic because it’s More Accuracy and Less Memory Consuming than the other Two Methods. Also it Proves the Feasibility of the Design Concept of Piecewise Variable Thickness for Radome.
Theoretical Study about the Formation of the Stacking Faults in GaN Nanowires along Different Growth Directions
Authors: Gong Xiao Jing , Zhang Jing Ping , Xu Ke , Wang Zhi Gao , Yang Hui , Yu Rong , Zhan Wei
Published: July 2011

Semiconducting nanowires offer the possibility of nearly unlimited complex bottom-up design, which allows for new device concepts. However, essential parameters that determine the electronic quality of the wires, and which have not been controlled yet for the III–V compound semiconductors, are the wire crystal structure and the stacking fault density. In this paper, we have used the molecular dynamics simulations to study the formation of the stacking faults in GaN NW along [0001] and [11-20] directions. The results show that under same growth condition the GaN NW along [0001] has stacking fault while there is no stacking fault in GaN NW along [11-20]. We have analysis the possible reason and further study is underway.
A New Speech Enhancement Method Based on Genetic Algorithm
Authors: Yang Yang
Published: July 2011

In this paper a new algorithm for speech enhancement is presented. In the proposed approach, the effect of noise is reduced from the singular values as well as the singular vectors. We utilize the Genetic Algorithm for optimally setting the parameters needed for our proposed speech enhancement process. In the case that the additive noise does not have the white noise characteristics, the GSVD operation is used for subspace division. The results indicate the better performance of our proposed method in comparison with other well-known speech enhancement techniques.
Using Depth Image in 3D Model Retrieval System
Authors: Liu Yong Guang , Zhou Ming Quan , Fan Ya Chun
Published: July 2011

For content-based 3D model retrieval, an improved depth image-based feature extraction algorithm is proposed. First, a 3-D model is preprocessed. Secondly, six depth images are generated in three principal directions in the normalized coordinate system. Thirdly, the eigenvectors of 3D model are obtained through 2D Fourier Transform of the depth images. Finally a new method is used for low-frequency sampling. Experiments show that the approach performed quite well despite its apparently simple approach. In our large 3D database, our approach is well for variant resolution models and holds satisfied computational costs.
Research on Construction of K-d Tree Based on Euclidean Distance
Authors: Ding Hua Feng , Wang Wei Qing , Zhang Yuan , Xiao Xing Jiang , Xu Jun
Published: July 2011

Traditional k-d tree is constructed according to the order in which data appear, so the balance and depth of the constructed k-d tree are not ideal. To overcome the disadvantages of the construction of traditional k-d tree, this paper proposes a new constructing method based on Euclidean distance so that the construction begins with the center of the data, and every time the points of the nearest distance are used to construct k-d tree, so k-d tree generated in this way is relatively better balanced and has better depth, therefore good searching performance is achieved.
Study of the Interaction of Shock Wave / Laminar Boundary Layer
Authors: Gouidmi Hamza , Beghidja Abdelhadi , Said Mohamadi , Benderradji Razik
Published: July 2011

We are interested In this study to the interaction between oblique shock wave, induced by a surface of a supersonic nozzle with an angle of inclination of θw=8.5°, by a laminar boundary layer generated by a flat surface (reflection of oblique shock on a flat wall) . We studied also the problem of the development of the interaction zone and its unsteadiness. Our study is based on complex numerical simulation of interaction of shock wave / boundary layer and on their disturbance found within the interaction zone. This is the area of unsteady physical characteristics. This study was conducted under condition that the flow is compressible, of laminar and two-dimensional character. We treated also the point of detachment of the boundary layer by varying the value of the upstream Mach number. We compared our results (obtained by the commercial code FLUENT) with those found numerically and experimentally.
The Effect of Longitudinal Slope’s Variation on Sedimentation in a Meandering River
Authors: Ghomrassi Hadhri A. , Mhiri Hatem , Lepalec G. , Bournot P.
Published: July 2011

In the present work, we conducted a numerical simulation of flow and sediment transport and deposition in a meandering river. The corresponding results were compared to experimental data of a physical river that was assumed to have a 0.001 longitudinal slope. A three-dimensional numerical model was simulated by means of the commercial FLUENT code. The latter used the RNG k-ε turbulence closure model whose ability to reproduce the experiments was compared to further models. The lagrangian tracking of particles (DPM) was performed. The adopted grid was non uniform, particularly refined on the wall zones where the sedimentation of particles took place. The hydrodynamic section of the model was checked using experimental data. The comparison of the sediment concentration numerical result gave a satisfying agreement with the experimental data. Once the model validated, we studied the effects of varying longitudinal slope on deposition of particles under a flow velocity of 0.2 m/s. The tested values are 0.001 and 0.0045.
Validation of BioDent TDI as a New Clinical Diagnostic Method
Authors: Ding Yao Yao , Adschiri Tadafumi , Williams Garry A. , Callon Karen E. , Watson Maureen , Naot Dorit , Costa Jessica L. , Reid Ian R. , Cornish Jillian
Published: July 2011

Indentation is a mature technique that has been widely used in materials science to investigate the mechanical properties of metals and thin films. The indentation technique provides accurate modulus and hardness values of materials over many length scales and can target specific microstructures within heterogeneous materials. A more traditional engineering approach for mechanical properties is three point bend testing which provides an indication of the general fracture performance of the material. The breaking force and toughness results determined are based on the materials overall structure and composition. However, for both techniques, the testing specimen requires certain degree of process. This study evaluated a new indentation technique, which is able to penetrate biological tissues, apply compressive loads on the bone surface and record the resulting displacement, using wild type rats fed with a standard diet. In this study, both femurs from the same animal were tested followed by the three point bending to reach structural failure. We found a correlation between the two techniques and the properties of the bone in the animal model.
Copper Coated Iron Powder Prepared by Chemical Reduction Process
Authors: Zhu Xiao Yun , Guo Zhong Cheng
Published: July 2011

Using reduced iron powder as raw material, Copper coated iron powder(CCIP) is prepared by electroless alkaline-based plating. We discuss the impacts of reductant concentration, plating solution temperature and main salt concentration on the properties of CCIP. Surface morphology and composition are studied by using scanning electron microscopy and X-ray diffraction. The results show that after coating, the iron powder surface is rougher and the copper layer is uniform in its simple metallic form without any oxide states.
Study of Preparation on the Flake Silver Coating over Copper Powder for Electronic Industry
Authors: Zhu Xiao Yun , Dong Man
Published: July 2011

Flake copper powder is coated with silver by using a solution containing [Ag(NH3)]+. Factors such as copper particle size distribution, [Ag(NH3)]+ concentrations and the dispersing agent are studied and correlated with the silver content of coated copper and electric conductivity. At the condition of silver concentration of 0.8 mol/L and dispersing agent of 1.0g/L a powder of copper coated with silver with electric conductivity of 0.8×10-3Ω•cm is obtained. XRD patterns indicate that the powder consists of only the Cu and Ag phases without other intermediate phases. SEM results with different silver contents reveal that when Ag content rises, its surface topography transforms through the steps: individual particles →small islands→continuous 2D layers →multi-layers.
Mechanical Behaviour of Ultrafine Grained Cu and Cu-(2.5 and 5) Vol.%Al2O3 Composites Produced by Powder Compact Forging
Authors: Mukhtar Aamir , Zhang De Liang
Published: July 2011

Nanostructured Cu-(2.5 and 5)vol.%Al2O3 composite powders were produced from a mixture of Cu powder and Al2O3 nanopowder using high energy mechanical milling, and then compacted by hot pressing. The Cu and Cu-Al2O3 composite powder compacts were then forged into disks at temperatures in the range of 500-800°C to consolidate the Cu and Cu-Al2O3 composite powders. Tensile testing of the specimens cut from the forged disks showed that the Cu forged disk had a good ductility (plastic strain to fracture: ~15%) and high yield strength of 320 MPa, and the Cu-(2.5 and 5)vol.%Al2O3 composite forged disks had a high fracture strength in range of 530-600 MPa, but low ductility.
Influence of Growth Rate on the Solute Distribution of Directionally Solidified Cu-Ag-Zr Alloy
Authors: Kang Bok Hyun , Lee Woo Hyun , Kim Ki Young , Cho Hoon , Noh Jae Soo
Published: July 2011

Cu-2wt.Ag-2wt.%Zr alloy was directionally solidified with different growth rates(V=10-200 um/s) at a constant temperature gradient(G=3.1 K/mm) in a modified Bridgman furnace. The influence of growth rate was investigated by observing the microstructure and measuring the solutes’ compositions within the Cu-matrix and dendrite boundaries. The experimental results show that increasing the growth rate, decreased both the primary and secondary arm spacing and increased micro-Vickers hardness. The solutes’ concentration also increased as a result of the back diffusion caused by a decreasing growth rate. The electrical conductivity depends on the solutes’ distribution.
Effects of Replication on Measured S-N Curves of Metals
Authors: Duan Kai , Beer Aiden G. , Clegg Richard E.
Published: July 2011

Replication, or repeated tests at the same stress amplitude, is used to provide statistical confidence in life data during the development of S-N curves. This paper discusses the effects of replication on the measurement of S-N curves and presents an alternative to traditional replication methods for the determination of S-N curves, particularly for the development of preliminary S-N curves. Using specimens made out of the extruded bars of a magnesium alloy, it is demonstrated that the S-N curve estimated using the data from non-replication tests is almost same as that from replication tests. The advantage of using non-replication fatigue tests is that it uses fewer specimens, in this instance, only half of that required for 50% replication fatigue test, to achieve the same estimation as that of the replication fatigue tests. Another advantage of using non-replication fatigue tests is that it can detect the non-linearity using limited specimens.
Thermal Shock Properties of Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 Composite Coatings
Authors: Salman Asma , Gabbitas Brian , Zhang De Liang
Published: July 2011

Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite coatings have a potential to reduce dissolution and aluminium soldering tendency of H13 tool steel used in the aluminium processing industry. The thermal shock resistance of H13 tool steel coated with Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite powders sprayed using a high velocity oxygen fuel (HVOF) technique was studied. The thermal shock behaviour of the composite coatings was investigated by subjecting the coated coupons to a number of cycles, each cycle consisting of a holding time of 30 seconds in molten aluminium at 700 ± 10 °C followed by quenching into water. The surfaces of the coupons were examined for Al soldering and an evaluation of surface spallation. Any cracks found in the coatings were studied to explain their thermal shock behaviour. The results of this study showed that both Ti(Al,O)/Al2O3 and TiAl(O)/Al2O3 composite coatings on H13 tool steel have good thermal shock resistance with a thermal shock life between 300 to 400 cycles. The composite coatings and fracture surfaces were analyzed using scanning electron microscopy.
An Impregnation Technique for Crack Identification Following Uniaxial Tension Tests
Authors: Alterman Dariusz , Akita Hiroshi , Neitzert Thomas Rainer , Alterman Justyna
Published: July 2011

This paper is dedicated to an impregnation technique for crack identification of uniaxial tensile behaviour of concrete samples. A method for crack identification in concrete after uniaxial tension tests was adopted for the observation of differences between various experiments which were conducted with and without the elimination of secondary flexure. During the procedure an epoxy resin containing fluorescent dye was infused into concrete samples by vacuum to expose cracks and defects. After impregnation the samples were sawed from the prism and pictures taken under ultraviolet light.
Influence of Hydrogen Plasma Treatment on a-SiC Resistivity of the SiC/SiO2/Si Structures
Authors: Gordienko S.O. , Nazarov A. , Rusavsky A.V. , Vasin A.V. , Rymarenko N. , Stepanov V.G. , Nazarova T.M. , Lysenko V.S.
Published: July 2011

This paper presents an analysis of the electrical characteristics of the amorphous silicon carbide films deposited on the SiO2/Si substrate. Aspects of RF plasma treatment on electrical and structural characteristics of a-SiC film are discussed. It is demonstrated that the dominant mechanism of current transport in the a-SiC thin film is determined by variable-range hopping conductivity at the Fermi level. Studies of the a-SiC film at temperatures from 300 K to 600 K also indicate that silicon carbide is a perspective material for fabrication of temperature sensor.
Model of Nonuniform Channel for the Charge Carrier Transport in Nanoscale FETs
Authors: Popov V.P. , Ilnitsky M.A.
Published: July 2011

Mobility degradation during gate length scaling is a well established experimental fact, which is confirmed also by Monte –Carlo simulation. We have analyzed the physical reason for this degradation using experimental and modeling data obtained in classic drift-diffusional approximation with electric field dependences of electron mobility. We have shown that this dependence is a main reason for mobility degradation in nanoscale FETs, which means also that the same reason will limit the drain current in future post-silicon CMOS generation with new materials like narrow band III/V compounds or graphene with the highest carrier velocity near 108 cm/s.
High Temperature Effects on Harmonic Distortion in Submicron SOI Graded-Channel MOSFETs
Authors: Emam Mostafa , Pavanello M.A. , Danneville F. , Vanhoenacker-Janvier D. , Raskin Jean Pierre
Published: July 2011

The effect of elevated temperature on the harmonic distortion in Graded-Channel MOSFETs is presented in this work. The Graded-Channel devices show interesting advantages in terms of nonlinear behavior compared to classical devices especially at higher temperatures up to 200°C.
Wettability, Electrical and Mechanical Properties of 99.3Sn-0.7Cu/Si3N4 Novel Lead-Free Nanocomposite Solder
Authors: Mohd Salleh Mohd Arif Anuar , Hazizi Muhammad Hafiz , Ahmad Zainal Arifin , Hussin Kamarudin , Ahmad Khairel Rafezi
Published: July 2011

A nanocomposite solder alloy with 99.3Sn-0.7Cu base alloy was successfully fabricated using the powder metallurgy route which consists of blending, compaction and sintering. Varying amount of nano size silicon nitride particulates were introduced as reinforcements to obtain a novel lead-free nanocomposite solder alloy. Following fabrication, the sintered nanocomposite solder were cut into thin solder disc and were analyzed in terms of their wettability, electrical and mechanical properties. Wettability, electrical and mechanical properties of the nanocomposite solder were compared to 99.3Sn-0.7Cu and 96.3Sn-3.0Ag-0.5Cu lead-free solder which were fabricated with the same method using powder metallurgy route. Wettability property of the nanocomposite solder was found to be in the accepted range with wettability angle below 45° similar to 99.3Sn-0.7Cu and 96.3Sn-3.0Ag-0.5Cu lead-free solder. Besides wettability, the results of electrical and mechanical properties analysis showed that additions of nano size Si3N4 had enhanced the strength and electrical conductivity of nanocomposite solder comparing to 99.3Sn-0.7Cu and 96.3Sn-3.0Ag-0.5Cu lead-free solder.
Study of the Electical Conductivity of Oil Palm Fiber Carbon
Authors: Indayaningsih Nanik , Zulfia Anne , Priadi Dedi , Hendrana Sunit
Published: July 2011

The physical properties of carbon from natural fibers are strongly influenced by the conditions of carbonization process. Temperature carbonization process of natural fibers affects the structure and electrical properties of carbon. This research studied the influence of carbonization process to the electrical conductivity and the microstructure of carbon from oil palm fibers. Oil palm fiber carbonization process has been carried out at the temperature of 500°C and 900°C for 1 hour in the atmosphere of inert gas (nitrogen) and at a temperature of 1300°C performed using a Spark Plasma Sintering (SPS). Structure of oil palm fiber carbon analyzed using XRD and SEM, electrical conductivity measurements carried out using LCR meter. XRD data analysis showed that the carbon structure is amorphous, and carbonization process up to 1300°C cause increase of the degree of crystallinity, that are 36.92%, 39.07% and 42.48% for 500°C, 900°C and 1300°C respectively. Increase of carbonization temperature also causes the electrical conductivity of carbon that are (3.3 x10-6) S/m – (4.8 x10-6) S/m for carbon 500°C, 1.29 S/m – 1.3 S/m for carbon 900°C, and (1.4 x10) S/m – (1.7 x10) S/m for carbon 1300°C.
Mechanical Properties Evaluation of Woven Coir and Kevlar Reinforced Epoxy Composites
Authors: Azrin Hani Abdul Rashid , Roslan Ahmad , Jaafar Mariatti , Roslan Mohd Nazrul , Ariffin Saparudin
Published: July 2011

The utilization of coconut fibers as reinforcement in polymer composites has been increase significantly due to their low cost and high specification of mechanical properties. Whereas kevlar fibers has widely used as the core material in flexible body armors due to its great mechanical properties, such as high strength, light weight, good chemical resistance and thermal stability. The research work is concerned with the evaluation of high speed impact and flexural test of hybrid textile reinforced epoxy composites. Samples were prepared from coir yarn, kevlar yarn, interlaced of coir and kevlar yarn with different warp/weft orientation and pure epoxy as control specimen. The woven samples were produced using handloom and the composites specimens were prepared using hand lay-up technique. From the results obtained, it was found that woven kevlar composites samples displayed the highest impact properties while it exhibits the lowest flexural properties. Results also showed that the composite plate for woven coir yarn (warp) and kevlar yarn (weft) has the flexural strength and impact strength of 17 MPa and 67 kJ/m², which presented as the nearest properties to woven Kevlar composite respectively. These results indicate that coir as a natural fiber can be used as a potential reinforcing material for high impact resistance such as body armors in order to reduce the usage of synthetic materials whilst utilizing the natural resources.
Current-Voltage Characteristics of Side-Gated Silicon Nanowire Transistor Fabricated by AFM Lithography
Authors: Hutagalung Sabar Derita , Lew Kam C.
Published: July 2011

Silicon nanowire transistor (SiNWT) was fabricated by using a silicon nanowire as a channel which directly connected to the source (S) and drain (D). In this work, a side gate (G) formation was used to develop a transistor structure. AFM lithography was performed to create the nanoscale oxide patterns via local anodic oxidation (LAO) mechanism. A conductive AFM tip was used to grow localized oxide layer on the surface of silicon on insulator (SOI) substrate by the application of voltage between tip and substrate. Other parameters that will influence the patterning process such as tip writing speed, relative air humidity, anodization time and substrate orientation were controlled. The patterned structure was etched with tetramethylammonium hydroxide (TMAH) and hydrogen fluoride (HF) acid to remove the uncovered silicon layer and silicon oxide mask patterns, respectively. The surface topography and dimension of the fabricated SiNWT was observed under AFM. Obtained results for the channel thickness, channel length and the distance between the channel and side gate are 32.92 nm, 7.63 µm and 108.07 nm, respectively. Meanwhile, the I-V characteristics of fabricated SiNWT measured at positive gate voltages are similar to p-type FET characteristics.