bluuebunny/crossref_metadata_2025 huggingface dataset:
A Multiscale Modeling Approach for Carbon Nanotubes
Authors: Sun Yu Zhou , Wang Jin Yan , Liew K.M.
Published: March 2010

This paper introduces a multiscale modeling approach for carbon nanotubes (CNTs), in which a fine continuum model that has been developed by the present authors is employed to implement the continuum modleing. The entire domain is decomposed into a continuum modeling region and an atomic region with an overlapping region. For the atomic region, the atomic finite element method (AFEM) is used to trace the individual atomic motion. Whereas, the continuum region is viewed as the higher-order continuum media, and the mesh-free method is adopted to implement the continuum numerical discrization. For the overlapping region, the bridging domain method is used to efficiently couple two scales. Numerical computation is carried out and several examples are discussed.
Synthesis and Photoluminescence Properties of Novel SnO2 Zigzag Nanoribbons
Authors: Liu Jian Xiong , Wu Zheng Yu , Meng Guo Wen , Zhan Zhao Lin
Published: March 2010

Novel single-crystalline SnO2 zigzag nanoribbons have been successfully synthesized by chemical vapour deposition. Sn powder in a ceramic boat covered with Si plates was heated at 1100°C in a flowing argon atmosphere to get deposits on a Si wafers. The main part of deposits is SnO2 zigzag nanoribbons. They were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). SEM observations reveal that the SnO2 zigzag nanoribbons are almost uniform, with lengths near to several hundred micrometers and have a good periodically tuned microstructure as the same zigzag angle and growth directions. Possible growth mechanism of these zigzag nanoribbons was discussed. A room temperature PL spectrum of the zigzag nanoribbons shows three peaks at 373nm, 421nm and 477nm.The novel zigzag microstructures will provide a new candidate for potential application.
An Improved Calibration Method for Optical 3D Measuring System Using Cross Target Based on Bundle Adjustment Algorithm
Authors: Xiao Zhen Zhong , Liang Jin , Yu De Hong , Tang Zheng Zong
Published: March 2010

This paper presents an accurate calibration method of binocular 3D measurement systems for industrial on-site inspection, which uses a cross target with ring coded points. The cross target can be used to calibrate large-scale field-of-view stereo measurement systems and obtain higher measurement precision conveniently. The world coordinates of these ring coded points are not required. The calibration initial value is computed by using the relative orientation method and the Direct Linear Transform (DLT) method of photogrammetry. The bundle adjustment algorithm is used to optimize the calibration parameters as well as the 3D coordinates of the ring coded points. Experiment results show that the RMS error of the reprojection in our method is less than 0.05 pixels and the measurement error is 0.011 mm compared with the Coordinate Measuring Machine (CMM).
Application of Pressure Test System in Dispenser for Gasoline
Authors: He Zhan Shu , Liu Ya Jun , Liu Jun , Wang Jia Bao
Published: March 2010

In the dispenser for gasoline there exist three problems: excessive pressure caused by water hammer, inadequacy of oil-gas separation and cavitation. A pressure test system of the dispenser for gasoline is established by using pressure transducers and a digital signal acquisition system. Results show that the pressure test system can not only conduct real-time and reliable diagnosis of the dispenser pressure, but also provide guideline on its performance optimization.
Study on the Technologies of Rapid Three-Dimension Optical Measurement for Welding Deformation of Sheet Materials
Authors: Xiao Zhen Zhong , Liang Jin , Yu De Hong , Tang Zheng Zong
Published: March 2010

To solve the problem of measurement for welding deformation of sheet metal, a non-contact three-dimension optical method is proposed. Firstly, photos of moving objects from different observation points are taken by two high-resolution and high-speed digital cameras simultaneously. Secondly, the three-dimensional coordinates of targets are calculated by three-dimensional reconstruction technique including collinear equation, photo orientation based on the coplanar equation, direct linear transform, epipolar geometric constraint and bundle adjustment method. Finally, the deformations at different moments are associated with points of the same name; the deformation of the observation points is calculated and the real time deformation curves are sketched. Compared with the traditional methods, this method is not subjected to the high temperature and strong interference and has the advantages of real-time, high efficiency and high precision. The application in the measurement for welding deformation of sheet materials is satisfying.
Research on Mechanical Fault Identification Based on Improved SVM
Authors: Chen Dong Di , Xiang Jia Wei , Zhong Yong Teng
Published: March 2010

Fault diagnosis of machinery is in essence a kind of classification problem. Utilizing the desirable classification ability of support vector machine (SVM) for fewer samples, a novel fault diagnosis method based on improved SVM was proposed. Some statistical features were extracted to reflect the equipment operational conditions and were input into fault classifier to attain the final diagnostic result. Experimental signals of gearbox were analyzed using the present method. The results of improved SVM were compared with those of artificial neural network (ANN). It indicates that the proposed method have better classification ability than that of ANN.
Research on High-Precision Measurement Platform for Optical Aspheric Surface and Corresponding Error Compensation
Authors: Ke Xiao Long , Guo Yin Biao , Pan Kun , Zhu Yong Lu , Luo Wei
Published: March 2010

With a hardware and software control scheme which including high-precision linear motors, contacting and non-contacting measurement sensor and a new developed of measuring software, this paper designs and establishes a high-precision measurement platform. This paper not only implements the hardware build, measuring software development, but also discusses corresponding error compensation, for example, probe radius compensation, rough error canceling and so on. The experimental results indicate that the measurement platform is suitable for high-precision measurement for optical aspheric surface.
Study on On-Machine Inspection Technology of Machining Center Based
Authors: Wang Shi Gang , Wang Yu Juan , Fu Yi Li
Published: March 2010

With the development of digitalized manufacturing (DM), on-machine inspection (OMI) has become the key link of integrated quality system in DM. In DM, The detection and monitoring system chiefly dealing with kinds of parameters in machining process, taking on-line detection, analyzing the process quality information and carrying out corresponding quality assurance, so the quality of product may be assured and DM can be run in good condition. Therefore, the OMI technology of machining center based is researched. The framework of OMI and the hardware structure of special driving card for probe or tool (SDCPT) are described. Computer aided inspection planning (CAIP) is the integration bridge between CAD/CAM and computer aided inspection. A feature-based CAIP system for OMI is proposed to inspect the complicated mechanical parts efficiently during machining or after machining. The CAIP system is designed to produce an inspection process planning directly from CAD model. The prototype CAIP system includes the tolerance feature analysis, accessibility analysis, feature identification, measurement planning, and collision detection. The CAIP system can minimize the number of part setups and probe orientations and the inspection feature sequence.
Device and Method for Large Size Aspheric Measurement
Authors: Zhu Yong Lu , Guo Yin Biao , Ke Xiao Long , Chen Lu Shuang
Published: March 2010

In this paper, the necessary instrument and control system called the “Large Size Four-axis Measurement System” which used for measuring large size aspheric surface have been designed and established. Then the development of semi-meridian measurement method on basis of large size four-axis detection system has been reported. The measurement paths were planed and the measurement program was performed on the IPC. The method can significantly reduced the align error caused by the aspheric center which is not coincidence with the rotation platform center. With the measurement system, an aspheric surface was successfully measured; whose radius of semi-meridian was 55 mm. The experimental results show that the developed methods are simple and rapid. The measurement accuracy can satisfy requirement of aspheric surface.
Post-Weld Quality Inspection for CO2 Laser Tailored Blank Welding with Vision Sensor
Authors: Zou Yuan Yuan , Zhao Ming Yang , Liu Lian Zhu
Published: March 2010

The traditional method for post-weld quality inspection is visual testing by people. Major limitations of this method are the subjectivity of judgments and time required to perform the inspection. With the increasing use of laser welding in the automotive industry, the manufacturers are struggling with the challenge to automate the quality inspection process. This paper discussed the automatic post-weld quality inspection technology by computer vision sensing for mono-thickness tailored blanks of CO2 laser welding. A visual sensor was developed for acquiring the original image of the weld seam. The sensor consists of a PC based vision camera and a stripe-type laser diode. An image processing algorithm was presented to detect the geometrical defects of the weld seam. Some experiments are carried out and some applications are given.
The compact Platform for In Situ Nanoindentation and Scratch Test
Authors: Huang Hu , Zhao Hong Wei , Deng Ji Qiang , Ma Zhi Chao , Hu Lei Lei , Yang Jie , Wang Xiao Yue , Ji Jia Bin , Zhang Zheng Peng
Published: March 2010

A kind of experimental platform for in-situ nanoindentation and scratch test has been developed, which has high resolution of displacement and can be used to carry out nanoindentation and scratch test. The precision driven element composing of flexure hinges and piezoelectric actuator was analyzed, which was used to realize indenter’s precision motion. The components, working principle and performances of testing platform were introduced. The calibration experiments of loading and displacement sensors were carried out, and it showed loading and displacement sensors had high linearity and stability. The indentation experiments were carried out on a kind of glass. The experimental results showed proposed testing platform had good reproducibility and scheme was feasible. The research work will provide theoretical foundation and key technologies for nanomechanics test, and has theoretical significance and application value to materials science, micro-electronics, precision optics and biomechanics, etc.
Research on Quality Evaluation System of Dynamic Alliance Based on Life-Cycle
Authors: Zhang Shao Jie , Yang Chun Li
Published: March 2010

Dynamic Alliance is becoming more and more important in manufacturing industry. Based on previous studies, a five-stage life-cycle of Dynamic Alliance is proposed in this paper. On the basis of life-cycle, taking into account both the entire life-cycle and each stage; the quality evaluation system was built. In this paper, the methods of Delphi and Multiple Factor Analysis were used to study the factors influencing the quality level at each stage, then quantitative conclusion was drew in the end. In addition, as the researches on Dynamic Alliance are still at the exploratory stage in manufacturing industry, this paper tries to provide references for further study.
Study of Simulation Tester for Key Rubbing Pairs in Internal-Combustion Engine
Authors: Yan Xin Ping , Yuan Cheng Qing , Liu Zheng Lin , Zong C.Q. , Bai X.Q.
Published: March 2010

A simulation tester was designed which could be used to simulate the wear and vibration of the key rubbing pairs in an internal-combustion engine, such as cylinder liner-piston ring, crankshaft and sliding bearings. Its pivotal innovation is that high pressure air was adopted to simulate the explosive pressure and pressure evolution in a cylinder to accord with the real conditions. Pressure sensors, vibration accelerations sensors, oil monitoring sensors and temperature sensors were installed at many points and directions on the tester support to form an on-line condition monitoring system via the developed software, which could simultaneously monitor the real-time wear and vibration condition for key rubbing pairs in internal-combustion engine. It is believed that the successful application of the tester for both tribological and dynamic characterization will be very significant to study the key rubbing pairs in internal-combustion engine.
Detection of Unbonds in Honeycomb Sandwich Structure Using Lock-In Thermography
Authors: Liu Hui , Liu Jun Yan , Wang Yang , Li Hui Juan
Published: March 2010

Lock-in thermography (LT), that is active infrared testing technology, mainly includes optical lock-in thermography (OLT) and ultrasound lock-in thermography (ULT). LT can be used to detect unbonds between honeycomb core and face sheet of sandwich structures. However, modulation frequency is an important influencing factor. In this paper, the principles of LT are represented, in experimental detections of simulated unbonds in honeycomb sandwich structures with Al-face sheet and CFRP-face sheet using OLT and ULT, detectability of OLT and ULT is compared and analyzed, effect of modulation frequency is researched and the optimal frequencies are obtained.
Fast Location of Thermal Target with Low Offset and Spatial Filter of Winner-Take-All Circuit
Authors: Wang Jun Qi , Chen Shu Jung , Shen Chih Hsiung
Published: March 2010

A new modified infrared tracking sensor array with spatial filter is proposed, which identifies the locations and sizes of thermal object efficiently with the winner-take-all (WTA) circuit and a low offset correlated double sampling (CDS) circuit. The winner-take-all (WTA) circuit is used in combination with active readout circuit for thermopile array. In this circuit, thermal image intensity has been chosen for the input saliency map. The removal process is performed by zeroing the values of the thermal image background intensity levels, so only the potential thermal objects of interest are compared by the WTA. The offset reduction with CDS technique enhances the sensitivity of winner-take-all (WTA) circuit and shows a sharp selectivity which makes it possible to pick up only one winner pixel from each thermal object. In order to simulate and present the infrared thermal sensor array in this paper, the sensor array is integrated by using a 2P4M 0.35μm standard CMOS technology. This proposed architecture shows a high resolution with two orders higher than the circuits without CDS. The results have shown that integrated thermopile array with WTA and CDS can approach a high level of development, reliability and easy for high accuracy infrared tracking applications.
Characteristics Identification of Overlapping Vibration Signals on Mallat
Authors: Sun Huer , Yang Zhao Jian , Liang Qun Long , Pang Xin Yu
Published: March 2010

In rotor-bearing system running, vibration signals measured were an kind of Multi-vibration source signals which is overlapping each other. These overlapping signals were difficult to be separated by the ordinary methods, which is adverse to precisely estimate faults of rotor-bearing system in running. In this paper, a test rig was set up to simulate mis-alignment faults; collected vibration signals of bearings were decomposed and reconstructed by algorithm of Mallat. Reconstructed signal can reflect detail character s of bearings vibration. And vibration signals characteristics of fault rotor were effectively identified.
Reliability Analysis of Prestressed Steel Structure in Regards to Temperature Action
Authors: Liu Zhan Sheng , Chen Zhi Hua
Published: March 2010

In order to study the impact of various cables expansion coefficients on the reliability of the prestressed steel structure, a finite element model of the beam string structure and a limit state equation controlled by applicability have been established. The Monte Carlo method based on Latin hypercube sample is adopted and APDL language is applied to write a corresponding program, thereby carrying out reliability calculation and analysis to the model; the system reliability and parameters sensitivity of the beam string structure under different cable expansion coefficients and temperature conditions are provided. The results indicate that the change of cable expansion coefficient has a great impact on the reliability of the structure; therefore, it is necessary to give precise linear expansion coefficient for different cables.
The Design of Mechanical System for Harbor Basin Wave Maker
Authors: Wang Shou Jun , Luan Liang Liang , Song Rong Sheng , Li Jun Yi
Published: March 2010

The design of mechanical system for harbor basin wave maker is introduced in this article. The installation form of wave maker is ground to pin type. The push-wave plate is driven by the AC servo motor and ball screw. The parameters of ball screw and the selection of servo motor are determined by calculating, and then check the bearing capacity of servo motor. The performance test has verified that the design of wave-maker system can meet the requirements.
Structure Buckling Non-Probabilistic Reliability Index Calculation of Ventilated Supercavitating Vehicles
Authors: Zhou Ling , An Wei Guang , An Hai
Published: March 2010

Supercavitating vehicles which cruise at a certain depth with high underwater velocity undergo high longitudinal force and circumferential pressure caused by ventilated cavity. The combination loads may cause structure buckling. Critical buckling loads coefficient of thin cylindrical shell with stiffened rings is obtained by semi-analytical FEM. The uncertainty of structural own parameters and ventilated cavitation number is described by interval sets, and then computational steps of COA for calculating buckling non-probabilistic reliability index (BNRI) are presented. It is analyzed that variety of each interval variable width, number and configuration of rings influence on the variety of BNRI in this paper.
Fuzzy Pattern Recognition of Steelmaking Process for Converter
Authors: Zhao Qi , Zhang Meng , Li Jia , Chen Yan Ru
Published: March 2010

A new method is proposed for recognizing patterns of the steelmaking process based on the light intensity from the mouth of converter. By analyzing the fuzzy theory and the measurement of variation characteristics of the light intensity, the fuzzy pattern recognition system is established. And a simulation with Matlab is then performed. The experimental results show that the fuzzy system can identify the prophase, metaphase and anaphase periods of the steelmaking effectively, and it provides a new method for the end-point auto-control of the converter steelmaking.
Study on Impinging Streams Reactor for Sewage Purification
Authors: Li Fu Bao , Wang Hui Lin , Li Qin , Wang De Xi
Published: March 2010

A new type of sewage treatment experimental device is designed, and so is its main equipment-impinging stream reactor. The advantages of efficient mixing and uniform reaction in the current impinging stream reactor are maintained, while vibration, shaft sealing failure and other issues in the propeller-type impinging stream reactor are overcome. The experimental results indicate that the equipment was running cost-effective and easy to operate. The outlook of the impinging stream technology for sewage treatment is forecast.
Analysis on Cutting Ability of Picks on Continuous Miner
Authors: Cao Yan Li , Li Xiao Huo , Sha Yong Dong , Liu Hong Mei
Published: March 2010

In order to obtain the continuous miner cutting ability of picks and its adaptability to coal, the average cutting force of continuous miner is got by means of the cutting electromotor power, and the cutting impedance is got compared with the single cutting resistance. It calculated and analyzed roller diameter, roller rotating speed, cutting power and the influence of the number of picks at work at the same time to the single cutting resistance.
Self-Adaptive Suppression of the Euler Beam Remnant Vibration Using the Interior Inlay Viscous Fluid Unit Method
Authors: Jing Dong , Xu Hui
Published: March 2010

In this paper a novel self-adaptive remnant vibration suppression method using interior inlay viscous fluid unit (IVFUM) has been investigated. The IVFU is imbedded in the flexible structure, that can self-adaptively reduce the flexible structure remnant vibration efficiently. In order to evaluate the effect of the IVFUM, the self-adaptive vibration suppression experiment for the IVFU Euler beam in the fixed frequency excitation and the rotating excitation were carried out.. We proposed the SDOF damping system model combined with the nonlinear least square fitting method to process the rotating remnant vibration attenuation signal and identify the rotating IVFU Euler beam modal parameters. Finally, it is demonstrated that the IVFUM for the remnant vibration suppression effect of the flexible Euler beam is efficient under certain conditions after experimental and numerical analysis.
The Realization of Monitoring System for Stacking Crane Using Plotting Finite State Machine
Authors: Li Li , Liao Xiao Ping , He Xin Biao
Published: March 2010

The goal of this paper was the development of a visual monitoring system for the management of stacking crane (moving within the aisles of the warehouse) using finite state machine (FSM). As usual, the implementation of a monitoring system required four preliminary steps: development of plotting FSM model, design of data exchange protocol, procession of operational monitoring data, visualization of a monitoring system. The paper was also presented form above contents. First, the operating characteristics of stacking cranes were analyzed to gain the operation control information and establish the plotting FSM model. Second, the data exchange protocol between the monitoring computer (MC) and the programmable logic controller (PLC) of stacking crane were designed based on the FSM model. Three, through the monitoring program, the operational data of stacking crane were gained and displayed in the visual monitoring platform. Finally, the visual monitoring system of stacking crane had been realized.
Effect of Reactive-Al2O3 Addition on the Pore Size Distribution and Thermal Conductivity of Carbon Blocks for Blast Furnace
Authors: Chen Xi Lai , Li Ya Wei , Li Yuan Bing , Sang Shao Bai , Zhao Lei
Published: March 2010

The effect of reactive-Al2O3 addition on the pore size distribution and thermal conductivity of carbon blocks for blast furnace was investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray, mercury porosimetry, and a laser thermal conductivity meter. The results showed that the pore size distribution and the thermal conductivity of carbon block were mainly influenced by SiC whiskers and reactive-Al2O3. With increasing addition of reactive-Al2O3, the mean pore diameter reduced and < 1μm pore volume increased of open pores owing to the more efficient filling of pores by SiC and reactive-Al2O3, and the thermal conductivities of samples increased due to the facts that the higher thermal conductivity of reactive-Al2O3 than that of brown corundum and the more formation amount of high thermal conductivity of SiC.
Statistical Analysis of the Effect of Na2CO3 as Additive on the Reduction of Vanadic-Titanomagnetite-Coal Mixed Pellets
Authors: Zhou Lan Hua , Zeng Fu Hong
Published: March 2010

Vanadic-titanomagnetite-coal mixed pellets with minor addition of Na2CO3 were reduced isothermally at 900°C, 945°C, 1100°C, 1255.4°C and 1300°C. The variables parameters studied are temperature, the amount of carbon and the amount of Na2CO3 as additive. The experiment was designed with the technique of orthogonal regression in order to quantitatively assess the effect of each variable and the interactional effect of different variables.
It is found that temperature, the amount of carbon and the amount of Na2CO3 as additive substantially influence the degree of reduction and metallization, and the presence of Na2CO3 can increase the reducibility of the pellets. The interaction of temperature and the amount of Na2CO3 have negative influences on the degree of reduction and metallization.
Study on Crack Retardation with the Consideration of Crack Surface Roughness by FEM
Authors: Xu Yan Hai
Published: March 2010

As one of the key factors to induce crack closure, crack surface roughness plays a dominated role in evaluating the characteristics of short fatigue cracks. The crack retardation induced by the crack surface roughness was investigated by numerical simulation in this paper. The influence of crack surface roughness on short fatigue cracks was directly applied into the numerical simulation procedure with the help of friction coefficients on the contacted crack surfaces. The driving forces of cracks represented by the two indicators such as crack tip displacement and plastic strain range were studied and used to characterize the retardation induced by crack surface roughness. It is shown that the evidence of crack surface roughness affecting on crack retardation is obvious and the influence of crack surface roughness on the characteristics of short fatigue cracks must account for in evaluating the performance of short fatigue cracks.
Probabilistic Crack Propagation Behavior of Railway B Grade Steel
Authors: Li Wei , Li Qiang , Wang Ping
Published: March 2010

Fatigue crack growth rate (FCGR) test of B grade steel was performed to clarify the probabilistic behavior of crack propagation in near-threshold region and steady-state region. As a result, a crack propagation law considering influence of threshold value and average stress can be well proposed to estimate crack propagation behavior of B grade steel. The estimated value of threshold value ΔKth is 293.65MPamm1/2, approaching the experimental value of ΔKth, about 280.39MPamm1/2. Furthermore, the probabilistic FCGR curves of B grade steel are established from the viewpoint of survival probability and confidence degree, which reflects the influence of scatter regularity of data and sample size on reliability assessment.
Microstructure and Mechanical Properties of Cast Ti25Nb3Mo3Zr2Sn Alloy
Authors: Wang Gui , Kent Damon , Paladugu Mohanchand , Yu Zhen Tao , Dargusch Matthew S.
Published: March 2010

The microstructure and mechanical properties of a cast near β type titanium alloy, Ti-25Nb-3Zr-3Mo-2Sn, have been investigated in this paper. In the as cast condition, the alloy possesses coarse, equiaxed β grains and Transmission Electron Microscopy(TEM) observations showed the ω phase is also present in this condition. The alloy in the as cast condition has low strength and is highly ductile. Direct ageing at 450°C for 4 hours leads to the formation of a large number of fine scale α phase precipitates. The alloy in the aged condition is less ductile but exhibits significantly enhanced strength.
Dielectric Tunable Properties of Ba0.6Sr0.4TiO3 Thin Films with and without LSCO Buffer Layer
Authors: Sun Xiao Hua , Feng Ping , Zou Jun , Wu Min
Published: March 2010

Barium strontium titanate Ba0.6Sr0.4TiO3 (BST) thin films were fabricated by pulsed laser deposition (PLD) technique on Pt/TiO2/SiO2/Si substrate with and without high (100) oriented LSCO buffer layer. Crystal structure and surface morphology of BST thin films with and without LSCO buffer layer were characterized by X-ray diffraction (XRD) and atom force microscope (AFM). The dielectric measurements were conducted on metal-insulator-metal capacitors at the frequency from 100 Hz to 1M Hz and at room temperature. It was found that the LSCO buffer layer was beneficial for BST films to decrease surface roughness, dielectric loss and to increase grain size, dielectric constant, tunability and figure of merit (FOM). The influence of LSCO buffer layer on the microstructure, dielectric and tunable properties of BST thin films were analyzed. At 1M Hz, the dielectric constants of BST films with and without LSCO buffer layer are 684 and 592, respectively. The tunability of BST thin film with LSCO buffer layer was about 65.48%, which was higher than that (about 41.84%) of BST thin film without LSCO buffer layer.
On the Warpage in the Lower Case of Lead-Acid Batteries
Authors: Hsieh Wen Hsiang , Shu Kuen Ming
Published: March 2010

The study aimed at improving the problems of warpage occurring in the mold injection of battery lower cases. Firstly, the effects of variations of molding parameters are investigated in order to minimize the warpage. Secondly, Moldflow software is employed to simulate the molten plastic flow inside the cavity, and followed by the holding pressure analysis. Moreover, Taguchi method is applied to find the optimum distribution of mold temperature, and its results are used to design cooling tubes. Finally, different cooling systems are parametrically simulated and the optimum combinations will be found. The analytical results indicate that the optimum parameters can reduce the warpage problem occurring during mold injection. Therefore, the yield rate of the products can be effectively raised.
Activated Carbon Fiber for Super-Capacitor Electrode
Authors: Zhang Xue Jun , Li Hai Yan , Tian Yan Hong
Published: March 2010

Activated carbon fibers(ACFs) were prepared from general pitch-based carbon fiber by steam activation and catalytic activation method, respectively. The surface area and pore structure of the resultant ACFs were analyzed by N2 adsorption, and electrochemical performances as electrodes of super capacitors were characterized by galvanostatic, cyclic voltammograms and AC impedance spectrum analysis. The results show that ACFs prepared by both methods have similar BET surface area, while their pore size and distribution are different. Compared with steam activation, catalytic activation results in ACFs with high mesoporosity of 40%. The electrode performances show that the specific capacitances of ACFs prepared by catalytic activation method could be 213 F/g, two times of that of ACFs prepared by steam activation method, and more mesopores are the reason for the good capacitance performance.
Surface Hardness Changes after Strengthening under Low-Amplitude Loads
Authors: Lu Xi , Zhu Ning
Published: March 2010

This document investigated the changes of the surface hardness of the front axle and transmission gear after strengthening under low-amplitude loads below the fatigue limit (SLAL). The experimental results showed that the strength changes of the front axle after strengthening under low-amplitude loads was almost proportional to hardness, but it was inverse ratio for the transmission gear. There was no difference in the change direction of surface hardness, caused by strengthening or damaging. The reason of surface hardness changes could be due to that the microstructure of material was improved after being strengthening under low-amplitude loads below the fatigue limit.
Influence of Perlite Admixture on Pore Structure of Cement Paste
Authors: Yu Le Hua , Ou Hui , Zhou S.X.
Published: March 2010

The parameters on pore structure of Portland cement pastes blended respectively with 0, 10, 20, 30 and 40% perlite admixture at 3，28，60 curing day were determined by Mercury Intrusion Porosimetre and presented in the paper to investigate affection on performance of cement-based material due to mix the admixture. The research results indicated that since the second hydration reaction had gone on with curing time, perlite admixture could diminish porosity, decrease pore diameter and reduce pore surface area in cement paste. Pores were gradually evolved from original small pores to later smaller pores, moreover fully filled with hydration products and disappeared during hydration reaction. So that the total pore volume in the paste was descended, and the proportion of harmless pores (gel pores and micropores) to whole pores was increased but that of harmful pores (macropores) subtracted. It is concluded that perlite admixture should help to increase the mechanical strength and durability of cement-based materials.
Study on Al-Doped ZnO Films Prepared by Magnetron Sputtering with Rapid Thermal Annealing Process
Authors: Wang Hua , Xu Ji Wen , Ren Ming Fang , Yang Ling
Published: March 2010

Transparent and conductive Al-doped ZnO (AZO) films were prepared by nonreactive DC magnetron sputtering with rapid thermal annealing process. The effects of sputtering power and annealing temperature on growth behavior, electrical rand optical properties of AZO films were investigated. The experimental results show that the sputtering power and annealing temperature had great influence on the electrical resistivity of AZO films due to the change of (002) orientation and grain size. The lowest electrical resistivity of AZO films was 5.3×10-4Ω•cm when the sputtering power was 100W and the annealing temperature was 200°C or above. The sputtering power and annealing temperature had little effect on optical transmittance, which was between 86% and 90%, but the absorption edge had a blue shift with the increase of sputtering power and annealing temperature.
A Study on Crack Propagation in Bi-Materials
Authors: Li Li Yun , Cao Fu Quan , Zhang Jie , Zhao An Ping , Tian Lu Lu
Published: March 2010

The growth of a crack in a bi-materials base under a building will cause the structure failure. The mechanism of this kind crack growth must be investigated. In this paper, a series of I-II mixed mode crack fracture experiments for bi-materials have been conducted. In some situations, a crack can grow from the weak medium concrete into the hard medium marble under compression load. The stress intensity factors KI ,KII and the first principle stress σ1 near crack tips have been calculated. The difference in crack propagation ability between the single-material and the bi-materials specimens are also studied. The experimental results are in accordance with the σθmax fracture criterion.
Analysis on Transmission Characteristics of New Axis-Fixed Cycloid Gear
Authors: Zhu Cai Chao , Liu Ming Yong , Du Xue Song , Xiao Ning , Zhang Bin
Published: March 2010

Due to those disadvantages of the cycloidal-pin wheel transmission, such as low efficiency, low bearing capacity and poor rigidity, a new kind of axis-fixed cycloid transmission is proposed after generalizing those advantages of axis-fixed drive, cycloid drive and oscillating-tooth drive. Special output mechanism is unnecessary here because the motion is exported directly by the cycloid gear. Thus, there are many advantages of this new transmission-simple structure, small size, high transmission efficiency and large torsional stiffness. The transmission theory and basic structure are analyzed and the formula for the transmission efficiency is derived. A prototype is manufactured and the efficiency experiment is carried out on the test bed. The experimental result verifies the correctness of the therotical analysis.
Study on the Relationship between the Thermoelectric Potential and the Wear of YW1 Cemented Carbide Inserts
Authors: Chen Shun Qing
Published: March 2010

The analysis and the test about the relationship between the wear and the thermoelectric potential of YW1 cemented carbide inserts have been finished in this paper. The influence rules and the influence extent of thermoelectric potential to the wear have been emphasized. Then the new method of forecasting the life of cemented carbide has been also discussed.
Study on Time-Correlated Leakage Predication Model of Nonmetallic Gaskets
Authors: Gu Bo Qin , Sun Zhen Guo , Li Y.Y. , Huang X.L. , Zhou Jian Feng , Shao Chun Lei
Published: March 2010

The time-correlated leakage characteristic of nonmetallic gaskets was analyzed. Considering the effect of the gasket material deterioration on the sealing performance, a time-correlated leakage predication model of nonmetallic gasket sealing connections based on the porous medium theory was proposed. Some tests were performed on compressed non-asbestos fiber gaskets, the leakage behavior was investigated and the coefficients in the leakage model were obtained by regression analysis of experimental data. The predicted leakage rates according to the model were compared with the data reported in some literatures, and the prediction accuracy was also validated. The presented time-correlated leakage model provides an effective way to predict the leakage rate and evaluating the life of gasket sealing connections.
A Numerical Method for Predicting the Young’s Modulus of Ceramic
Authors: Zhou Xin Zhu , Zheng Jian Jun
Published: March 2010

This paper presents a numerical method that can predict the Young’s modulus of ceramic with reasonable accuracy. By introducing periodic conditions, the distribution of pores in the matrix phase is simulated. The lattice model is then employed for the analysis of stress in the pore structure and for the determination of the maximum element length. Finally, the validity of the proposed numerical method is preliminarily verified with the experimental results obtained from the literature.
Research on the Key Technologies for New Large Dual-Platen High-Precision Clamping System
Authors: Chen Jian , Wang Jin , Lu Guo Dong , Ling Zheng Qi
Published: March 2010

High- precision and large scale are the developing trend for injection molding machine clamping system .This paper compared the characteristics of three-platen toggle and dual-platen hydraulic clamping system. The key impact factors that effecting plastic parts` precision from clamping system were discussed systematically first time. Based on these analyses, a new clamping system has been proposed and manufactured to improve the plastics parts` precision, including three new technologies: new type dual-platen structure, parallelism adaptive correction technology and numerical controlled hydraulic servo system technology. It has been applied in practical machine successfully, and experiment result proves that it is effective enough to satisfying the high-precision molding of large plastics parts.
Experimental Comparison of Fatigue Characterizations between TRIP and DP Steels
Authors: Hu Zhi Gang , Zhu Ping , Meng Jin , Lai Xin Min
Published: March 2010

Advanced high strength steels are increasingly utilized to realize the lightweight of automotive body for economical and ecological considerations. The fatigue durability of notched components is one of the significant evaluation parameters for reasonable material selection. Strain-controlled fatigue experiments of low-alloy TRIP steel and DP steel with 590MPa grade were performed at room temperature in this study. Experimental results indicate that both fatigue life and cyclic stress amplitude of TRIP steel are superior to those of DP steel at the same strain amplitude. Furthermore, local strain-life models of two steels were determined with linear regression method to predict the fatigue life of notched body structures with finite element method. It can be concluded that TRIP steel can provide more excellent potential than DP steel for the lightweight design of notched automotive structures from the viewpoint of fatigue resistance.
Effects of Thermal Exposure on the Mechanical Properties and Microstructure Stability of an Al-Cu-Mg-Ag Alloy
Authors: Duan An Jing , Liu Zhi Yi , Gao Li Fang
Published: March 2010

Mechanical properties and microstructural evolution of an Al-Cu-Mg-Ag alloy during thermal exposure at elevated temperature were characterized by means of tensile tests, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observation. The tensile test results suggested that tensile strength (σBbB) and yield strength (σBsB) reduced with both increasing exposure time and temperature. When exposed at 150°C, the Al-Cu-Mg-Ag alloy exhibits good structural stability due to the splendid thermal stability of the Ω phase. SEM results showed that the specimen was fractured in a combined manner of intergranular and transgranular fracture. TEM results suggested the reduction of mechanical properties of samples was attributed to the coarsening of Ω phase and the precipitation of θ phase during thermal exposure.
An Experimental Investigation on Static and Dynamic Fracture Properties of MgAl
Authors: Zhong Wei Zhou , Luo Jing Run , Song Shun Cheng , Huang Xi Cheng
Published: March 2010

Three-point bending specimens of MgAl are loaded by MTS material testing equipment and Hopkinson pressure bar. Strength ratio of MgAl subjected to static compression loading is gained. The dynamic response of three-point bending specimen subjected to impact loading is simulated by ABAQUS finite element software. The stress distribution around crack tip is like shape of butterfly. It indicates that stress decreases quickly away from crack tip. Strain gauges are affixed at the swings of butterfly in the experiments and can experience higher strain signal. So the choice of strain gauge position is reasonable. Based on finite displacement method and the least multiplication value theory, dynamic stress intensity factors at different loading velocities are obtained. According to crack initiation time, dynamic initiation toughness is computed. The results indicate that dynamic initiation toughness of MgAl varies at different loading rates and increases with ball velocity.
Fatigue Crack Growth Behavior in Fusion Zone of 16MnR Steel Weldment
Authors: Xiong Ying , Shao Chang Zhe , Zheng Han Ying
Published: March 2010

Fatigue test is carried out for 16MnR steel weldment. The compact tension (CT) samples with 3.8mm thickness are used, and comparisons of fatigue crack growth between base metal and fusion zone in the weldment are considered in Paris region. It is shown that fatigue crack growth rate in the base metal is not sensitive to R-ratio, but the crack growth rate in the fusion zone increases with R-ratio increasing. To the low R-ratio, the crack growth rate in the fusion zone is smaller than that in the base metal, but they approximate the same under the high R-ratio. The mechanism of fatigue crack growth is analyzed through crack growth path in the microstructure, the different of fatigue crack growth behavior is studied for the base metal and the fusion zone.
Three-Point Bending Test Behaviour of a QFN Semiconductor Package
Authors: Abdullah Shahrum , Yunoh Mohd Faridz Mod , Jalar Azman
Published: March 2010

This paper discusses some issues in micromechanical property of a newly developed Quad Flat No-lead (QFN) 3D stacked die package using three-point bending test approach. The relevant test methodologies were carried out in order to observe the flexural stress, strain, maximum load and deflection of the package. While performing the test, these QFN packages were positioned on the three points test bench, and the specific applied load was then applied and moved down until the package was clearly bent and broken. The related findings indicated that the maximum load was found to be at 251.52 N and the maximum deflection was obtained at 0.41 mm. The results were important for setting related testing parameters (load, stress and strain) before applying the three point cyclic bending test on the QFN stacked die package as the future work.
The Study of the Relationships between Material Properties and Welding Residual Stresses
Authors: Tsai Yao Long , Chang Chin Chun , Chou Chang Pin
Published: March 2010

The objective of this study is to explore the influence of the steel’s material properties on the distribution of welding residual stresses of the butt-welded steel plate. First, S15C carbon steel’s material properties are varied in this study to calculate the corresponding welding residual stress by carrying out 3D finite element analyses. Results show the maximum longitudinal tensile residual stresses increase linearly with increasing thermal expansion coefficient and increasing yield stress. The length of the tensile residual stress zone decreases linearly with increasing thermal conductivity. Finally, based on the relationship between material properties and welding residual stresses, a useful prediction equation is developed and verified in this study.
Material Constitutive Model in Machining 7050-T7451 by Orthogonal Machining Experiments
Authors: Fu Xiu Li , Wang Hui , Wan Yi , Wang Xiao Qin
Published: March 2010

Material constitutive model for metal machining is very difficult to obtain and establish accurately by conventional tension and compression tests. The dynamic mechanical properties and material model during machining aluminum 7050-T7451 are studied by means of orthogonal machining experiments (including quick-stop experiment, cutting force and cutting temperature measurements). Compare with compression tests (SHPB), the established material model with large strain (0.8~1.9) and high strain rate (0.45×105~1.89×105) in this paper is more valid and reliability in simulation and analyzing machining process.
Microstructural and Mechanical Aspects of High Nitrogen Steels at Cryogenic Temperature
Authors: Zhang Zu Rui , Li Hua Bing , Jiang Zhou Hua , Li Zhen
Published: March 2010

Charpy V-Notch impact tests of N1, N2 and N3 steels from 77K to 293K are possessed in this paper. With increasing the nitrogen concentration, the ductile to brittle transition temperature (DBTT) increases. The toughness of the tested steels decreases rapidly with decreasing the temperature. The change of fracture patterns of high nitrogen austenitic stainless steels is dimple → shallow dimple → mixture of quasi-cleavage facet and dimple → cleavage facet. Fracture facets with river patterns, with tear ridges, along annealing twin boundary and cross the annealing twin plane are observed in this investigation. Critical dislocation density of crack tips ρc=[6π(τp)2/(KIc)2]2 can affect ductile to brittle transition (DBT) behavior at cryogenic temperature. Deformation twinning is also frequently observed at cryogenic temperature. Crack forms along the coherent twin boundary between one twin and the matrix.
The Calculation of Kinetic Parameters in Manganese Nitriding
Authors: Zhang Jin Zhu , Luo Shui Hui , Xu Chu Shao
Published: March 2010

The present work confirmed and achieved the relevant parameters which belong to the manganese nitriding model via experiments. Based on the metallic iron nitriding model and the nitride layer growth model, metal manganese nitrding model was set up. The change laws between the kinetic parameters and temperature of the solid metal manganese nitriding model was studied by using the optimum method. The experimental results showed that the ratio of weight gain for samples relatively increased with the increasing of nitriding temperature, and the results obtained from the numerical model indicated that the kinetic parameters of manganese nitriding model increased with the increasing of nitriding temperature.
Preparation and Characterization of Ba0.6Sr0.4TiO3 Ceramics Doped with Al3+, Ga3+, and In3+
Authors: Qian Juan Juan , Wang Xiao Yan , He Xi Yun , Qiu Ping Sun , Sun Da Zhi
Published: March 2010

Ba0.6Sr0.4TiO3 materials doped with boron family Al3+, Ga3+ and In3+ are prepared by a ceramic process. The specimens possess condense microstructures. A low dielectric loss is achieved in the sample doped with In3+. Dielectric constants increase with decrease of the radii of doped ions. The results are discussed with respect to the interaction between oxygen ions and ions at B-site in ABO3 perovskite, which is revealed by Fourier transform infrared spectrum.
The Modulus Mensuration of Yada Model and the Microstructure Simulation of Casting AZ31 Magnesium Alloy
Authors: Li Hong Bo , Lu Mei , Luo Jun Ting
Published: March 2010

Both experimentation and calculation of the Yada model modulus of casting AZ31 magnesium alloy are provided in this paper. Based on revised Yada model, the microstructure simulation of precision forming inner gear is performed using Superform software. On the basisi of result analysis, the microstructure transformation of the casting magnesium alloy in the hot-forming process is forecasted in terms of revised Yada model.