bluuebunny/crossref_metadata_2025 huggingface dataset:
Monte Carlo Simulation for an Electrical Discharge in O2
Authors: Zeghichi Leyla , Mokhnache Leïla , Djebabra Mebarek
Published: April 2011

The generation of plasmas and the initiation of electrical breakdown are realized by the phenomenon of electrical discharge which is provoked when we apply a sufficient electric field in a gas. Consequently the free charges are accelerated, new charged particles are created and others are destructed. This can be ranged in four phenomena: elastic collision (recombination), attachment, excitation and ionization. The aim of this paper is to study the basic phenomena in an electrical discharge in the case of Oxygen O2. Monte Carlo Simulation is used to follow the random trajectory of free charges determining in each path many parameters of the discharge. To determinate electrical and physical parameters, we have used the sampling laws. The spatial distributions of space charges (electrons, positive and negative ions) are also obtained. The determination of electrical field depends on distributions of charged particles obtained by solving the Maxwell equations.
Microstructure and Wear Behaviour of Al/TiB2 Metal Matrix Composite
Authors: Popoola Patricia Abimbola , Pityana Sisa , Ogunmuyiwa Enoch
Published: April 2011

Al/TiB2 metal matrix composite (MMCs) was fabricated on aluminium AA1200 with the aim of improving the wear resistance property of the substrate. The characterization of the MMCs was carried out by Optical Microscopy (OM), Scanning Electron Microscopy (SEM/EDS) and X-ray Diffraction (XRD). The microhardness and wear resistance tests were achieved. Results showed that the microhardness property of the AA1200 was increased by three times the original value and the wear resistance was also significantly improved.
Analyses of Plasmas Produced by Laser Ablation of Fresh Aliments
Authors: Beldjilali Sid Ahmed , Hermann Jörg , Baba-Hamed Tewfik , Belasri Ahmed
Published: April 2011

Detection and analysis of trace mineral elements in vegetables, and more generally in food by laser-induced breakdown spectroscopy (LIBS) promises applications with expected outcomes in nutrition quality. LIBS ensures contactless, real-time measurements of multielemental samples without any preparation of the samples surface. However, its application to analyses of aliments such as vegetables has one main drawback. Organic materials are strongly inhomogeneous and the physical properties that govern the processes of laser energy absorption, material ablation and plasma formation depend on a large number of parameters making calibration with standard samples impossible. This technique requires therefore a calibration-free approach that allows one to deduce the relative elemental concentrations from the intensities of spectral lines emitted from the laser-produced plasma. The main difficulty of such an approach is related to the temporal and spatial variation of the plasma properties. Therefore we have performed spectroscopic analysis of the plasma produced by Nd:Yag laser ablation of potato flesh and skin. The emission spectra recorded with an Echelle spectrometer with ICCD detector were compared to the spectral radiance computed for a plasma in local thermal equilibrium to deduce the mass fractions of the mineral elements.
On the Electron Distribution Effect of an Expanding Laser Ablated Plasma
Authors: Bennaceur-Doumaz Djamila , Bara Djemai , Djebli Mourad
Published: April 2011

Based on the Gurevich distribution function, the effect of trapped electrons by the electrostatic potential rising during plasma expansion is investigated. The self similar approach is used to find the expanding profiles of density and velocity. The present work may be used to understand the salient features of the expansion of plasma produced by laser ablation.
High Intensity Laser Ablation of Titanium Target
Authors: Yahiaoui Kenza , Kerdja Tahar , Malek Smail
Published: April 2011

In thin film deposition by pulsed laser ablation (PLD), the mass ablation rate depends on laser energy, on the pulse duration and on the thermodynamic properties of the ablated materials. In order to optimize the PLD technique and the films quality, the evolution of the amount of the ejected materials with laser irradiance, the SEM images of the laser impacts on the target and the ion yield in the vapour plume, were used. This allows us to predict the different mechanisms that are responsible to mass ablation according to laser irradiance which was ranging from 1.5108W/cm2 to 5.51010 W/cm2. Three diagnostics devices have been used: A quartz microbalance placed in front of the target, where the maximum of materials ejection occurs, a Scanning Electron Microscope (SEM) was used to show the impact morphology evolution with the laser irradiance and a charge collector, biased at negative voltage, was used to measure the ions yield and ions kinetic energy. The results show the evolution from normal evaporation mechanism at moderate laser irradiance to phase explosion mechanism at higher laser irradiance. Laser irradiance threshold for phase explosion onset is well determined by microbalance measurement, SEM micrographic pictures and the laser breakdown in the vapour plume was determined by the charge collector.
Characterization of CNx/Si Using RBS, NRA and AES Techniques
Authors: Siad M. , Abdelli-Messaci Samira , Kerdja Tahar , Lafane Slimane , Abdesselam M.
Published: April 2011

Carbon nitride films were synthesized by pulsed laser ablation of graphite target under nitrogen ambience. The third harmonic of a pulsed Nd-YAG laser of 355 nm wavelength and 7 ns pulse duration was focused onto a rotating target at an incidence angle of 45°. The laser fluence at the target surface was set at 30 J/cm2. The carbon nitride films were deposited on (100) silicon substrate kept at room temperature and placed at a distance of 40 mm from the target surface. The CNx films were grown under N2 gas in the pressure range of 5×10-3 to 4×10-1 mbar. The deposited films composition was investigated by different techniques RBS, NRA and AES. We found an N/C ratio equal to 0.4 in the pressure range cited above.
Effect of Laser Fluence on the Properties of Sm1-XNd X NiO3 Thin Films Deposited by KrF Laser Ablation
Authors: Lafane Slimane , Kerdja Tahar , Abdelli-Messaci Samira , Malek Smail , Maaza Malik
Published: April 2011

In this contribution we study the effect of the laser fluence on the stoichiometry, morphology and density of Sm1-xNdxNiO3 thin films. The latter were grown by a KrF excimer laser (λ = 248 nm, τ = 25 ns) ablation of a rotating target onto unheated (100) silicon substrates for 9000 pulses at different laser fluences into vacuum. The target used was a mixture of samarium, neodymium and nickel oxides. The relative ratio of neodymium (x = 0.45) is set to have a transition temperature close to room temperature (TMI = 310 K). The target-substrate distance was maintained at 4 cm. The composition and the morphology of the deposited layers were analysed by energy dispersion X-ray spectroscopy (EDX) and scanning electron microscope (SEM) respectively. It was found that films properties depend strongly on the laser fluence. The EDX measurements revealed that the laser fluence must be higher than 1 Jcm-2 for a congruent evaporation. However, even at this condition, the films were deficiency in oxygen. The morphology study showed that the films surface was widely contaminated by droplets for fluences superior to 2 Jcm-2. Also, it was found that by increasing laser fluence the films density increases and reach a plateau at 1.3 Jcm-2. According to all those elements, the laser fluence was set to be in the range of 1.3 – 2 Jcm-2.
Characterization of Laser Induced Plasmas by Fast Imaging for Graphite Target
Authors: Siouani Chaouki , Abdelli-Messaci Samira , Kerdja Tahar , Malek Smail
Published: April 2011

Plume expansion dynamics of an ablated graphite target by the third harmonic of Nd-YAG laser of 355 nm wavelength has been investigated using an ICCD camera fast imaging. This study was carried out into vacuum and methane (CH4) atmosphere at different pressures. Into vacuum, the two dimensional spatio-temporal evolution of plasma plume was performed at a laser irradiance range of 5.5x108 - 6x109 W/cm2. The plasma mean velocity has been estimated and was found to increase with laser power density increases until it reaches a maximum value of 107 cm/s. In presence of gas, the plasma plume dynamics was studied at a fixed irradiance of 4.3x 109 W/cm2 and from 0.05 to 5 mbar CH4 pressures. The plasma spatio-temporal evolution was found to be influenced by the gas pressure. In earlier time the expansion was almost linear independently of the background gas pressure used. However, as time evolves, the plume is decelerated, then presented a stationary behaviour at 1 and 5 mbar. Furthermore, the light emission from the plume very close to the target surface exists until a few microseconds into vacuum and CH4 atmosphere and then vanishes. It appears again around 10 µs following by the emission of particulates as bright incandescent tracks.
Comparison of the Capability of Peak Function in Describing Real Condensation Particle Counter Profiles
Authors: Djebara Abdelhakim , Khettabi Riad , Kouam Jules , Songmene Victor
Published: April 2011

Accurate measurement of the aerosols concentration is important in many applications of aerosol science. Here we compare the adequacy of a peak function with the profiles distribution given by a particle counter (CPC) classified in the size range 5 to 500 nm, issued in a machine shop. The particle counter uses a laser source and an optical system for the detection of particles. Our experiments lead to some underestimation of the profile. This underestimation corresponds with the parasitic phenomena of air bubbles and water droplets which are recorded by default as particles. The results of this study underscore the compatibility of a function Gaussian modified by exponential with the distribution profile given by the particle counter (99%).
A Decision Making Methodology to Divide Virtualized Resources Morphologies
Authors: Chen Xiao Jun , Zhang Jing , Li Jun Huai
Published: April 2011

The resources are divided into curable and non-curable morphologies to improve the efficiency of virtual computing systems, and we determine the quantities of such two morphologies based on resources required and resources that system owes. In the environment of tasks presenting random distribution, we describe the trend of resources required and compute the range interval of curable morphology by theoretical analysis. It is concluded that the amounts of tasks have great effect on resources required and the experiments show that the trend of decision variables in our numerical example is consistent with the theory discussed. The decision making methodology presented in this paper has some significance to the management of resources in virtual computing systems.
Effect of Laser Modification Welding on Formation of Aluminum Alloy
Authors: Xu Fei , Yang Jing
Published: April 2011

Effects of laser modification welding (LMW) on formation of full-penetration weld were studied, which were based on the laser beam welding (LBW) process of 5A02 aluminum alloy. The results indicated that the welding defects (such as undercut, surface depression and so on) could be improved obviously, and the microstructure of joint by LMW could be finer than that of joint only by LBW. Besides, the strength and toughness of joint would also be increased to some extent by LMW after full-penetration LBW. Therefore, the LMW is an effective method in order to strengthen joint of LBW.
The Experimental Research of Axlehousing Hydroforming Processing
Authors: Wu Na , Wang Geng , Wei Yun Ping
Published: April 2011

The axle housing manufactured by hydroforming can meet the requirement of light weight in automotive making. The products are of reasonable thickness distribution, high strength and rigidity. The application time of hydroforming axle housing in automotive manufacturing is not so long, its theory and process research is still not enough, accumulation of its experiences of test data and deformation regulation is rare, all this lead to difficulty in manufacturing design. Aiming at above problems, this thesis takes 1:2 scale samples of a 0.75t truck axle housing to hydroforming test and research, so as to search the regulation of axle housing hydroforming. By the use of different loading path in the two step of the processing, reasonable loading paths to the axle housing hydroforming are found. By the study of the broken tube, hydrorming limit diagram is drawn.
Study on Rotary Characteristics about Light Type Hydraulic Excavator
Authors: Yang Jing , Quan Long , Yang Yang
Published: April 2011

In order to analyze rotary characteristics of light type hydraulic excavator, according to prototype’s real parameters, a 3-D model of excavator was built using Pro / E design software, and import into the software ADAMS to build the virtual excavator, while using the AMEsim software to build the main components of multi-way valve characteristics model, etc.. After the simulation model of hydraulic system was developed, rotary characteristics were simulated and researched through experiments with different moments of inertia which change in the heavy-load operating mode. On the basis of the analysis and comparison with the results of simulation and experiments, the law between hydraulic system pressure variation and energy consumption about light type hydraulic excavator was obtained with different moments of inertia when excavator rotating.
Effect of Austenization Holding Time on the Martensitic Transformation in 30CrNi3MoV Ultra-High-Strength Steel
Authors: Qiao Zhi Xia , Zhang Dan Tian , Liu Yong Chang , Yan Ze Sheng
Published: April 2011

Any heat treatment technology must begin with the process of austenization, during which the holding time at austenite region is one of the critical parameters. The effect of austenization treatment holding time on the martensitic transformation in the 30CrNi3MoV ultra-high-strength steel was investigated by means of dilatometric measurements and microstructural observations. The results showed that extending the holding time at 900 oC won’t cause obvious coarsening of austenite grains due to the dragging effect of vanadium solute atoms adsorbed at austenite grain boundaries. Martensite microstructures obtained in the 30CrNi3MoV samples that were heat treated with different holding time varied a little. The austenization holding time has obvious influence on the Ms of the 30CrNi3MoV steel, because it simultaneously affect the size of prior austenite grains and the configuration of dislocation defects.
The Flow Stress Characteristic and Constitutive Equation of 6016 Aluminum Alloy in Warm Forming
Authors: Zhang Ji Xiang , Wen Hui , Feng Wei , An Guo Yin , Liu Jin Xi
Published: April 2011

In order to realize numerical simulation of warm forming and reasonably establish the warm formation process parameters for 6016 aluminum alloy, we study the forging process of 6016 aluminum alloy with warm compression experiments on the Gleele-1500 thermal simulation testing machine, and research the deformation flow stress behavior of the aluminum alloy sheet at different temperatures , strain rate under the warm forming. The results show that the deformation temperature and strain rate have significant influence on flow stress of 6016 aluminum alloy sheet, that is, the alloy is a temperature and strain rate sensitive materials, and the flow stress increases with the increase of strain rate and decreases with the increase of deformation temperature. The deformation constitutive equation of 6016 aluminum alloy is got by multiple linear regression analysis. The constitutive equation is consistent with the experimental curves rather well, which confirms the accuracy of the constitutive equation.
The Finite Element Simulation Study on Plow Bit’s Resistance during Cutting Coal and Rock
Authors: Hao Zhi Yong
Published: April 2011

Establishing the plow cutting coal seam 3D simulation model, Using finite element analysis software ANSYS/ LS-DYNA, simulating plow bit cutting coal seam process. under Through this study, obtaining the plow speed, cutting resistance of plow bit’s time process curve, analyzing the influence on cutting resistance of different cutting depth, separation distance and width.
Plasma Carburizing and Post-Treatment of Austenitic Stainless Steel
Authors: Zheng Shao Mei , Zhao Cheng
Published: April 2011

Plasma carburizing of AISI 316L austenitic stainless steel was carried out at low temperature to improve the surface hardness without degradation of its corrosion resistance. And the post-treatment, namely electrochemical surface brightening process was carried out to clear away a layer of thin black film on the plasma carburized samples and improve the surface quality of the hardened stainless steel. The surface appearance, roughness, microstructures, microhardness and corrosion resistance of the samples before and after brightening were analyzed and compared. Experimental results of plasma carburizing at low temperature showed that high-quality hardened layers can be produced at the appropriate process parameters.The electrochemical brightening process can be used as a post-treatment to restore the original color and further improve the corrosion resisitance of the plasma carburized stainless steel.
The Application of Ground Penetrating Radar in Railway Tunnel Concrete Quality Detection
Authors: Qi Su , Chen Xing Xing
Published: April 2011

The priority of traditional tunnel concrete quality testing method is drilling core .The traditional method damage tunnel structure and detection speed is slowly.we use this method cann’t effectively meet the demand of rapid growth of tunnel concrete qulity testing. So the more fast and effective detection methods are needed.A new fast and effective kind of concrete quality detection methods is ground penetrating radar can meet the extensive tunnel concrete nondestructive testing. This paper introduces the basic principle of ground penetrating radar.I illustrate the application of railway tunnel testing by the testing in Ju Gan runnel of Lan Yue railway.TI is significance for railway tunnel concrete in future.
Return to Original Purity and Simplicity"- Creative Product Design Research
Authors: Ren Cheng Yuan , Zhang Xian
Published: April 2011

The design objective is to satisfy people's needs, improve the quality of life, the pursuit of human, natural and social harmony. This article mainly elaborated the guidance in product design is the natural substance and natural elements, grasping the true feelings, returning to the initial, plain, true desire and behavior, discussing the design idea and method of return to original purity and simplicity, and will be up to a new value of passionate life, natural life and how to achieve certain value and meaning in creative product design.
Study in Simulated Heat-Affected Zone of Ship Steel
Authors: Liu Wen Yan , Liu Ji Bin , Zhu Cong Mao , Wang Hui
Published: April 2011

The experiments were carried out upon the determination of simulated heat-affected zone continuous cooling transformation (SH-CCT) diagrams, the characteristics of microstructure and Vickers hardness of SH-CCT specimens, and impact toughness in simulated coarse grain heat-affected zone (CGHAZ) of ship steels under different heat input based on physical simulation. The SH-CCT diagram reveals that bainite is always obtained in a wide range of cooling rates. When the maximum cooling rate reaches 100 °C/s (t8/5=3 seconds), the maximum fraction of martensite (8%) is obtained and the microstructures mainly consist of lath bainite and the hardness is only 255 HV. This demonstrates that the steel has a low quench-hardening tendency and excellent resistance to cold cracking. There are no obvious hardening and softening phenomena in simulated CGHAZ. Test results of impact toughness under different heat input in simulated CGHAZ show that the impact energies reach over 30 J at -40 °C when t8/5 is less than 20 s, meeting the stipulated requirements of ship steel (≥22 J at -40 °C) but no great allowance. Thus, to meet the requirement of properties during welding, it is proposed to choose t8/5 ranging from 5 to 20 s, correspondently the line energies ranging from 14 to 37 KJ/cm for 30 mm thick plate.
The Brief Analysis on Automobile Color Design
Authors: Qi Mi
Published: April 2011

In the industrial design domain, any choice including the modeling, the material, the processing craft and so on intrinsic factors can entrust the product with different character finally, thus causes it to adapt each kind of different market. In all design method, color design can be called an important link that affect product’s direct-viewing vision effection, the union of the color and the shape constitutes the most main and the most direct part of human vision feeling. The automobile is typical example that melt the modeling and the color together.
Dynamic Model and Experimental Research on Pitch Mechanism of Gun with Clearances
Authors: Li Bing , Chen Ren Yue , He Zheng Jia
Published: April 2011

The clearances in pitch mechanism of gun, such as barrel-guide, have important influence on firing accuracy. Since the sliding pair is the typical characteristics of slide plate of gun barrel and guide’s contact, the clearance can be simplified to the cantilever beam with a small gap. Dynamics models which influence the factors on cantilever clearance are established by cantilever clearance sets. The influence of clearance and the flexibility of clearance are simulated and vilified by numerical analysis. The results of the experiments are that the response signals in time domain reflect clearance size: in the same intensity under sinusoidal excitation, with enlargement of the clearance, the peak value of gun barrel time-domain signal is smaller. The current work can be referred by the gun firing accuracy design.
The Willing for Companies to Build the Logistics Cost Control System of Supply Chain and its Influence Factors
Authors: Yang Yi Min
Published: April 2011

In this paper, we use survey data from 165 enterprises in Hunan Province, in addition, we take in the Probit model to make empirical analysis about the willing for companies to build the logistics cost control system of supply chain and its influence factors from the following four aspects: the features of enterprise, the features of senior management, the external environment as well as the expected market. The results show that the willing for companies to build the logistics cost control system of supply chain is not strong. Among them, the willing is significantly correlated with the firm size, the type of senior management, the awareness of cost control system of logistics, government support policies and cost management techniques as well as its methods of development, while the willing has negative correlation with the nature of corporate, the risk expectations and the expected cost. In addition, the education of senior management and the behavioral factors of peer competitors have the same expected direction with our paper, but not significantly.
Research on Doubly-Fed Induction Machine Speed Control System in Marine
Authors: Zhang Zhi Qiang , Zhuang Ya Ping , Yu Lin Gang , Wu Zheng Guo
Published: April 2011

Application of doubly-fed variable speed system in motor-generator station is a new field in marine. This paper introduced the theory of doubly-fed variable speed and the design of doubly-fed system, adopted stator flux orientation vector control in induction motor by rotor current control with inverter. A kind of simple and fast starting device was designed, thus the power demand of inverter was reduced greatly. Experiment results showed that doubly-fed induction machine was good for speed adjusting and transient speed change rate was smaller than 1%.
The Loading Analysis and Strength Calculation for Slide Block Universal Spindle
Authors: Shi Jia Lian , Wang Xi , Liu Lei Gang
Published: April 2011

The loading pressing on slide block universal spindle under the friction situation is studied, and the calculation formula of the strength is derived in this original paper. Using the calculation formula, the strength of the slide block universal spindle in the 1100-mm blooming mill in an Iron And Steel Company is calculated. Through analysis, the conclusion is obtained. The distribution law in the stressed surface of the spindle drum’s unit pressure will be changed consequence of friction and wear, and the change of the loading condition promotes the wear of the slide block and the destruction of the fork.
Colloidal Polystyrene-Carbon Nanotubes as Water-Based Lubricant Additive
Authors: Li Xue Feng , Yan Han , Peng Shao Xian
Published: April 2011

A new type of water-based lubrication additive — colloidal polystyrene-carbon nanotubes (PSt-CNTs) has been prepared. Transmission electron microscope shows that the PSt-CNT colloids are tubes with tiny balls in nanometer scale. Four-ball test results indicate that both the load-carrying capacity and anti-wear of the colloidal PSt-CNTs are much superior to those colloidal PSt owing to the additive reinforced by CNTs. The optimum colloidal PSt-CNT content is 1.0 wt.%. The worn surfaces were analyzed using scanning electron microscope. Finally its lubrication mechanism was speculated preliminarily.
Finite Element Analysis of X-Cor Sandwich’s Compressive Modulus
Authors: Dang Xu Dan , Wei Meng , Wang Xin Li , Xiao Jun
Published: April 2011

By contrasting the two finite models, a practical finite element computational model of X-cor sandwich’s compressive modulus was proposed. Through numerical analysis the X-cor sandwich’s stress field and compressive modulus were achieved and the effects of changing Z-pin’s radius, density, angle and volume fraction to the X-cor sandwich’s compressive modulus were analyzed. The numerical analysis results indicate that as the Z-pin’s angle increases the X-cor sandwich’s compressive modulus decreases, as the Z-pin’s radius, density and volume fraction increase the X-cor sandwich’s compressive modulus increases. Through the computation of finite model the influencing trends of X-cor sandwich’s parameters are achieved and the rationality of the proposed finite model is verified.
Numerical Simulation of PC Steel Bar Induction Heating Process
Authors: Zhao Qian Zhe , Liu Yi Bing , Liu Yan Ping , Zhou Wei Song
Published: April 2011

Based on electromagnetic and temperature field models of nonlinear ferromagnetic materials, this paper conducts a finite element analysis of the induction heating process of PC steel bar, thus obtaining the change curves of temperature, active power, heating efficiency and power density. The main factors and mechanisms affecting the heating efficiency and the temperature uniformity are analyzed systematically by a combination of the simulation result and the experimental fact. This work is expected to contribute significantly for optimizing the key parameters of induction heating production of PC steel bar.
The Light-Sensitive Character of WO3 Nanorods Synthesized by the Hydrothermal Method
Authors: Fu Xiao Ming , Pan Wei Jun , Yang Zai Zhi
Published: April 2011

Crystalline WO3 nanorods of less than 100 nm in diameter have been successfully synthesized at 240 °C for 72.0 h with pH=1.5 in the system of strong acid with sodium tungstate and potassium sulphate by the hydrothernal method. The morphologies and structures of WO3 rods have been characterized and analyzed by XRD, SEM, TEM and SAED. SEM confirmed that the slenderness ratio of WO3 rods was enlarged with the increase of t the pH value and the reaction time. SAED analysis showed that the crystal morphology of the synthesiezed WO3 nanorods was crystallin. UV-VIS results showed that the absorbent power of UV light for WO3 nanorods enhanced with the increase of their slenderness ratio.
A Review of Research about Variable Intake Manifold
Authors: Zhao Fu Guo
Published: April 2011

This paper is an overview of research about variable intake manifold in the past 12 years. First, a brief introduction to the basic principle of the variable intake is given.Then, the research of variable intake manifold in these years is presented and discussed, and the important studies are described in detail. Finally, the paper gives a summary of the research status and prospects of variable intake manifold.
Semi-Active Landing Gear with MR Fluid Damper Based on ADAMS&MATLAB Co-Simulation
Authors: Pawale S. S. , Wang Hai Jun
Published: April 2011

According to MR fluid properties and MR damper structure, a multi-body dynamic model of semi-active landing gear was built by using virtual prototype in ADMAS/Aircraft. Fuzzy control system for the semi-active landing gear with MR damper was designed under the MATLAB/Simulink environment. Co-Simulation of ADAMS/Aircraft and MATLAB/Simulink were carried out. The simulation results show that semi-active landing gear with MR damper based on fuzzy control strategy can reduce the aircraft’s vibration and improve the ride comfort characteristics. Co-simulation method provides one simple feasible method for the process of landing gear design, development and manufacture. It also offers a new way to advance designing quality for complex dynamic system and control strategy simulation.
Electrical- Magnetic Transport and Magnetoresistance in La 0.7 Ca 0.3 MnO3/BN Composites
Authors: Zhu Yong Dan , Liao Hong Hua , Tan Jian Jun , Zuo An You , Yi Jin Qiao , Sun Lin Jiao
Published: April 2011

The electrical–magnetic transport properties of (La0.7Ca0.3MnO3)(1-x)/(BN)x composites has been investigated systemically by conventional solid-state reaction method. The results of X-ray diffraction (XRD) and scanning electronic microscopy (SEM) show that BN and LCMO coexist in the composites and BN mainly goes into the grain boundary region without any chemical reaction with La0.7Ca0.3MnO3, which are in accordance with the results of the magnetic measurements. It is very interesting that with increasing of BN content level (x < 0.25), the metal–insulator transition temperature (TP) remains constant (nearly at 275K), and the resistivity increases very slowly. But when x > 0.25, TP shifts to lower temperature and the resistivity increases dramatically. The resistivity threshold of the composites occurred at x = 0.25, and specially the magnetoresistance (MR) reaches a maximum value (about 26.32 %) at 100K in an applied magnetic field of 3kOe. The results also indicate that the doped BN has an important effect on the low field MR (LFMR), which results from spin-polarized tunneling.
Simulation Experiments on Two-Phase Flows in Shaking Ladle
Authors: Zhang Jun , Chu Shao Jun , Ni Shan Qiang , Li Zhong Si
Published: April 2011

Increasing requirement of MCMnFe & MCCrFe in steel enterprises, the applying of the shaking ladle process is also adapted by more and more ferroalloy enterprises. Changing the speed of rotation, the phenomenon of the oil/-water interface motion is investigated by simulation test under the different eccentric distance, volume ration of oil to water, and speed of rotation. The results show that with the same ladle diameter and eccentric distance, and the increase of the speed of rotation, the state of Oil/Water interface motion is changed from oscillatory motion to lotus-leaf state motion, and finally the emulsifying state motion. Among the three states, the emulsification state is the required movement with the full agitation and fast mass transfer speed. The more the eccentric distance and the less Voil/Vwater, the less the critical speed of rotation is, and vice versa.
Lap Joint Properties of FSBRed Dissimilar Metals AZ31 Mg Alloy and DP600 High-Strength Steel with Various Parameters
Authors: Zhang Chang Qing , Li Bo Qiang , Wang Xi Jing
Published: April 2011

The Friction stir blind riveting (FSBR) process consists of a blind rivet is driven at high rotational speed and brought into contact with the workpieces, thereby generating frictional heat between the rivet and the workpiece, which softens the workpiece material and enables the rivet to be driven into the workpieces under reduced force. The riveting of lap joint of AZ31B(3mm) magnesium alloys plate and a DP600 (1mm) high strength steel plate was produced by FSBR using 2200rpm rotation speed, various feet rates and different lap mode to investigate the effects of the joint morphology and strength. The joint strength depended strongly on the shank of rivet itself shear strength，however in which case the strength of joint impacted by rivet assembly quality (the lap of plates, the tightness rivet of workpiece). So positioning the steel sheet on the top is desirable, the maximum shear strength of the joint reached about 6.0KN.
The Three-Dimensional Parametric Model and Interface Designing of Involute Spline Broach
Authors: Zhang Guang Guo , Zhang Hong Hua , Jiang Wei , Wang Huan
Published: April 2011

When design the spline broach,it refer to many parameters, large calculated amount , tedious teeth design and long design cycle .this Papers according to structural parameters of involute spline broach,establishe 3D parameter models with Solidworks. based on the secondary development environment of Solidworks and Visual Basic Language,build explanation mechanism, interface design, run the program realize The geometric constraint Parametric Modeling of involute spline broach. The digital platform of involute spline broach for design take shape initially,short Design cycle improve design precision ,come true broach design automation.
Hydraulic Fault Diagnosis Expert System of Excavator Based on Fault Tree
Authors: Li Guo Ping , Zhang Qing Wei
Published: April 2011

The constituting of diagnosis expert system and the basic theory of fault tree analysis were introduced at first. A model of combining fault tree with expert system was analyzed. It focused on the hydraulic excavator PC220-7 for Komatsu according to the hydraulic system breakdown of law and order was particularity. A method combined the fault tree analysis with an expert system based rules was adopted. It was expressed systematically expert knowledge by building a fault tree. According to the fault tree, a database of diagnostic rule can be automatically generated. Automatic diagnosis knowledge acquisition has become reality. A hydraulic system fault of excavator was given as an example to design an expert system with the function of complex reasoning and explanation. It provides a reference for hydraulic excavator of the use of management and fault maintenance personnel to solve excavator problems. It shows that this method has a good application in the future.
The Analysis of Dynamic Characteristics in Reduction of the Circular Saw Idling Noise
Authors: Wang Xiao Ling , Yin Zhong Jun , Zhang Chao
Published: April 2011

We investigate the natural frequency and the amplitude of circular saw blades during idling. We use four blades in the paper: 1) The traditional circular saw blades, 2) The circular saw blade with damping materials which is distributed in the core of blade, and the circular saw blade has a uniform thickness, 3) Similar to the above one but the circular saw blade has a non-uniform thickness, the damping region is thicker than other region of the circular blade, 4) the circular saw blade with damping material which is distributed around the core of blade by four small circular regions. We adopt the Finite Element Method in our numerical analysis. Our analytical results are very useful for a better design of circular saw blades.
Numerical Simulation of Transport Characteristics of Porous Metal Fiber Sintered Felts Used in Microreactor for Hydrogen Energy
Authors: Zhou Wei , Song Rong , Wan Zhen Ping , Tang Yong
Published: April 2011

The porous metal fiber sintered felt (PMFSF), a new catalyst support, was successfully used to construct a methanol steam reforming microreactor for hydrogen production. To study the transport characteristics of PMFSFs, a three-dimensional model with the cubic pore cell structure for PMFSFs was established. Using computational fluid dynamics fluent software, the velocity and pressure distribution when the fluid through the PMFSFs was investigated by changing the porosity of PMFSFs and inlet velocity of the fluid. In addition, fluid temperature distribution was analyzed under different inlet velocities by setting the temperature of fluid and wall. The result shows that the PMFSFs greatly enhance the transport characteristics because of its three-dimensional network structure and microchannel structure, it will become an ideal candidate for catalyst support material.
Control of Yield Ratio Based on Ultra Fast Cooling and Mechanical Behaviors of High Strength Aseismic Steel
Authors: Kang Jian , Yuan Guo , Wang Zhao Dong
Published: April 2011

The new generation TMCP process based on ultra fast cooling has recently developed rapidly. In order to develop the low yield ratio constructional steel, the effects of cooling finishing temperature on microstructure and yield ratio of steels were studied primarily. The results show that the high strength and low yield ratio can be achieved by multiphase including M-A hard second phase and bainite ferrite soft matrix. When UFC final temperature is 521°C, the uniform M-A phases with volume fraction of 22.5% are distributed on bainite ferrite matrix, and then the yield strength is 570MPa, tensile strength 760MPa, yield ratio 0.75, and percentage elongation 22% with the Charpy impact energy 284J at -40°C. All these indexes come up to the relevant standards. The steel with lower yield ratio can be subjected to larger plastic deformation before the necking instability.
Study on the Electrical Arc Ablation Performance of Nano-SiCW Reinforced Cu-Matrix Composites
Authors: Liu Gui Min , Li Bin
Published: April 2011

The nano-SiC whisker reinforced Cu-matrix composites (SiCw/Cu) were obtained by powder metallurgy processes. The electrical arc ablation performance of composite SiCw/Cu was compared with copper H62 through stagnation-point ablation experiments. The results indicated that the qualities of copper H62 samples decreased with the increasing of ablating current; and the qualities of SiCw/Cu samples firstly increased and then decreased with the increasing of ablating current. Ablation mechanism research indicates the ablation hole of SiCw/Cu is smaller than copper H62, but it produced micro cracks because of different thermal expansion coefficients between nano-SiC whisker and Cu-matrix. At the same time, nano-SiC whisker happens to intricate oxidation reaction during arc ablation, it can reduce Cu-matrix smelts and sprays by absorbing arc energy. The anchoring effect and protection for the copper matrix of the uniformly dispersing nano-SiC whiskers have been considered to contribute the excellent arc ablation performance of composite SiCw/Cu.
Enhanced Performance of ZnO-Coated LiNi0.5Mn1.5 O4 Cathode Materials for Li-Ion Battery
Authors: Zhang Wan Hong , Yue Min , Wang Tao
Published: April 2011

ZnO-coated LiNi0.5Mn1.5O4 cathode materials for Li-ion batteries have been synthesized. Samples were characterized by scanning electron microscopy (SEM), X-ray diffractometry (XRD) and charge-discharge tests. The results of XRD and scanning electron microscopy (SEM) showed the ZnO-coating was nano-sized, and the LiNi0.5Mn1.5O4 powder exhibits a typical cubic spinel structure with a space group of Fd3m. Electrochemical tests demonstrate that the ZnO-coated sample obtained possesses high capacity and excellent cycling stability compared with the as-prepared LiNi0.5Mn1.5O4. When being discharged at a rate of 1C after 50 cycles, the ZnO-coated LiNi0.5Mn1.5O4 powders can still deliver a capacity of 115.5 mAh•g-1, with nearly no capacity fading, which shows to be a potential cathode material for high-energy density power batteries.
LFC Mold Development of Complex Parts with Free-Form Surface
Authors: Xiao Xiao Feng , Xue Qiong , Xiao Ke Feng , Hu Xiao Lan
Published: April 2011

This paper has analyzed key techniques in foam mold development for Lost Foam Casting for different types of casting, which are complex box, pipe faucet junction ,wear-resisting and refractory alloy steel casting, Focused on complex castings with free-form surface, key points during whole technical route, which includes three-dimensional modeling, foamed pattern design, mold design and CNC program, have been discussed by utilizing modeling & manufacturing module on Unigraphics. Because of its perfect free-form surface functions and plentiful toolpath operations in CNC programming, Foam mold of complex casting with free-form surface has been designed, manufactured and assembled successfully for LFC, Qualified foamed pattern of vortical shell has been produced successfully. Several effective methods and experiences have been achieved by utilizing CAD/CAM technology.
The Application of Moldflow in Injection Mold Design of Mobile Phone Cover
Authors: Zhang Wen Jian , Zhang Qi
Published: April 2011

Based the CAE technology, the paper introduced the application of Moldflow Insight in injection mold design of mobile phone cover. First, we must preprocess the finite element model, including importing three-dimensional model, meshing, and process setting. And then, we can use preliminary simulation analysis to determine the number and location of the gate. Finally to filling, cooling, packing and warpage analysis for part which can help us to find the causes from warpage generated. By optimizing the molding process parameters, adjusting the dwell pressure and the dwell time we can get less warpage, which can meet the precision demand of parts, consequently, the result can provide gist for the mold designers to design and for the injection molding technologist to process parameter adjustment.
Microstructures and Properties of Tungsten Carbide Particle-Reinforced Composites Fabricated by Overlaying Welding with Flux-Cored Wire
Authors: Li Lian Jie , Dai Le
Published: April 2011

The wire was made by Tungsten Carbide(WC) particles as core. MIG welding was used to surface iron-based WC wearable composite coating of different size and content of WC particles on mild steel. Microstructure was investigated. Surface rigidity and wear resistance were tested. The results indicate that the small particles are dissolved seriously, which separate out with reticulation. The hardness and wear resistance of the matrix are relative higher. The big particles are dissolved less, tree crystal separates out along particles. The particles are easy to fall off when wearing. So the hardness and wear resistance of the substrate are relative lower. The admixture with 80% big particles and 20% small particles has the best wear resistance, its wear resistance can achieve quintupling of quenching 45 steel. The hardness and wear resistance increase with content of WC increasing.
Development of Hot Press Machine for Superplastic Forming Technology
Authors: Lee Ho Sung , Yoon Jong Hoon , Yoo Joon Tae , Yi Yeng Moo
Published: April 2011

In most superplastic forming process, one or more sheets of superplastic grade materials are heated and forced onto or into single surface tools by gas pressure. Since the assembly includes only clamping dies, temperature chamber and regulated gas pressure to provide forming force, the assembly is easy to use for aircraft components. However, it is not easy to control process variables at high temperature. This paper presents an economic machinery method to develop hot press machine for manufacturing complex contoured components using superplastic forming and diffusion bonding technology.
Size Effect on the Micro-Extrusion Forming of Zr-Based Amorphous Alloys
Authors: Wu Xiao , Xue Chun E
Published: April 2011

Micro-extrusion of a Zr-based bulk metallic glass in its super-cooled liquid state is explored as a method to create objects of cup-shaped micro-parts. The effects of overall dimensions of the samples and the ratio of inner diameter to out diameter (i) on the forming are determined. The results reveal that the apparent viscosity of the forming liquid increases along with the rises of i or with the decrease of the overall dimensions, and the increasing speed is more quickly while i is greater than 0.833, which suggest that there exists significant size effect. More generally, the results suggest that large i, and a low overall dimensions are attributes indicating difficulty for forming.
Computer Aided Styling Design in Automobile
Authors: Wei Sun , Hou Ying Chun
Published: April 2011

According to China Association of Automobile Manufactures statistics, China’s automobile production and sales ranked first in the world in 2009. Although China has become a big country of automobile manufacture, the research and design capabilities of automobile is still weak, especially in styling design. How to use computer aided technology to promote the development of car styling design is the aim of this article. CAS (computer aided styling) may be is a good choice. First, comparing the different among traditional styling design process, CAD design process and CAS design process, this article points out the benefits brought by CAS; Second, this article explain the details of CAS design in car styling design; Finally, this article analysis the character of CAS which is important to apply CAS correctly. If Chinese auto companies could apply CAS well in car styling design, the industry of China automobile will enter a new phase.
A New Computational Model about Vehicle’s Sliding Resistance Coefficients
Authors: Lin Hong Liang , Yu Qiang , Zhang Xue Li
Published: April 2011

Vehicle’s sliding resistance mainly includes rolling resistance, air drag resistance and friction within the transmission, wheel bearings and other related components. Among those, rolling resistance and air drag always exist whenever vehicle is running, so they have great influence on vehicle’s dynamic performance and fuel economy. Therefore, it is important to determine vehicle’s rolling resistance coefficient and air drag coefficient quickly and accurately in order to operate vehicle properly and reduce the vehicle’s fuel consumption. Combining theoretical analysis with experimental verification, calculation model based on road coasting test was given by means of least squares principle. And through which vehicle rolling resistance coefficient and air drag coefficient were determined easily. Then by using the test data from some Minibus, the vehicle's rolling resistance coefficient and air drag coefficient are calculated according to established model. The computation result shows that rolling resistance coefficient is a linear function of the speed and the air drag coefficient is constant. Finally, the analysis shows that the calculation model is simple, precise and useful.
Agent Model and Reasoning Mechanism for Task-Aware in Virtual Assembly
Authors: Hou Wen Jun , Li Tie Meng , Liu Chang Hua , Yang Fu Xing
Published: April 2011

Virtual Assembly (VA) is an advanced tool for assembly design. Current VA system lacks of intelligent decision support especially in assignment of assembly planning task. There are already some research to enhance the perception ability and intelligent support of VR. However, most of them are focusing on the auto mating or moving navigation, while the study on assembly task is few. The paper analyzed the task in virtual assembly and discussed the system level task as a main topic, which indicated that ‘work-flow’ was a suitably way to implement task aware. Therefore a BDI agent model for assembly task was proposed on the bases of work-flow and the architecture of it was given. After these, the reasoning mechanism was designed to support assembly task awareness.