bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Hysteretic Model of SRHSHPC Frame Joints Considering Accumulative Damage
Authors: Zheng Shan Suo , Yu Fei , Wang Bin , Zhang Hong Ren , Hu Yi
Published: November 2010

To reflect the effects of accumulative damage of steel reinforced high strength and high performance concrete (SRHSHPC) frame joints on its mechanical properties such as strength and stiffness degradation under reversed load, a damage index (D) is introduced into hysteretic model of SRHSHPC frame joints. Then a trilinear load-displacement hysteretic model of SRHSHPC frame joints considering accumulative damage is proposed, which can reveal strength and stiffness degradation of SRHSHPC frame joints. Five 1:4 reduced-scale models of SRHSHPC frame joints were constructed and subjected to low cyclic reversed loading to gain the value of those parameters in the D. The calculated results tally with the experimental results well, and it is showed that the proposed hysteretic model considering accumulative damage has a considerable precision.
Redesign of a Substructure for a Milling Machine Using Topology Optimization
Authors: Chen Ting Yu , Huang Jain Jr
Published: November 2010

This paper deals with the redesign of a machine tool substructure which reinforces the working table of a gantry type milling machine. The original design of the reinforcing structure is a grillage structure to strengthen the working table. In order to improve the design, the cutting edge technology of topology optimization is employed to redesign the reinforcing structure. The result obtained by topology optimization shows that the redesigned topology of the reinforced structure is totally different from that of the original design. With the same material used, the stiffness and the natural frequencies of the working table are much higher than the original design. Even with a less amount of material use, the stiffness and the natural frequencies are still improved significantly.
An Ultrasonic-Frequency Pulsed Arc Approach to Improve the Life of Plasma Cutting Electrode
Authors: Wang Jia You , He C.H. , Huang J.Z , Chen J. , Fang C.F.
Published: November 2010

The present work proposes an ultrasonic-frequency pulsed arc approach to improve effectively the service life of oxidative plasma cutting electrode, and introduces the implementation and principle of the pulsed arc system. A number of electrode arcing experiments were then carried out to demonstrate effectiveness of this novel way. Experimental results show that this ultrasonic frequency pulsed process can contract the cathode zone of the arc while speeding up the movement of the cathode spots, and thus reduced the scope and depth of erosion pit on the hafnium electrode. The life of the electrode was finally increased by 47.8% at the pulse frequency of 40 kHz.
Surface Roughness Assessment of Micro-EDM by Wavelet Analysis Based on Goodness of Fit Test
Authors: Chen Zhi Jie , Shen Ji Hong , Guo Li Bin
Published: November 2010

The surface topography errors of Micro-EDM are mainly composed of surface roughness, surface waveness and so on, which have influence on the workpiece’s functions and performances in various degrees. Thus, how to pick up these errors without distortion is quite important for evaluating the surface topography. It is well known that Wavelet Transform has good time-frequency localization properties, which is especially suitable for image processing. Therefore, in this paper, a wavelet method for surface roughness of Micro-EDM is presented, in which, the time of wavelet decomposition is determined by Pearson Chi-square goodness of fit test. Furthermore, the results of simulation and experiments show that the proposed methods can separate Micro-EDM’s surface roughness well, meanwhile, using the mean and variance of ideal surface as accuracy requirements of the reference surface could help the separation have a certain certainty and precision.
Towards Cooperative Robotic Swarm Recognition: Object Classification and Validity
Authors: King David , Breedon Philip
Published: November 2010

Currently in cooperative transport research each agent can identify object validity. The validity is identified through a distinguishing feature, such as the object being lit. This paper examines the scenario where individual agents cannot assess the validity of an object. For example a triangle and hexagon may appear the same to an agent looking at a small section of the object. An arena containing half valid and half invalid objects was designed and implemented using a swarm simulation hexagonal grid test bed. The objects appear identical to an individual agent but are dissimilar, the objects were represented as imprecise triangles and hexagons. The swarm assessed each object as a group to determine its validity. Two different strategies were compared for dealing with invalid objects ranging the number of agents from 10 to 30. Initial testing has concluded that by ignoring invalid objects once identified required, on average, 1.28 times the amount of energy consumption to complete the task than when the invalid objects were removed.
A Floating and Self-Actuating Friction Drive Device for a Revolving Stage
Authors: Chen De Sheng , Song Hong , Lou Fei Yan
Published: November 2010

Friction drives offer certain advantages over gears. In particular, they generally run more quietly and are easier to manufacture than geared units. The friction drives used in revolving stages call for a large driving radius in order to reduce friction force. In traditional friction drives, the two friction wheels (driving and driven) must be highly and precisely circular. This makes the manufacture of the driven wheel difficult and uneconomical. In this paper, a floating and self-actuating friction drive device was developed with the use of a swinging gearbox. In this device, the driving wheel is floatable, so the driven wheel is permitted to have certain deviation of roundness in the make and certain eccentricity in the installation. This avoids the difficulties in making and installing the driven wheel. This is a strong point in the applications of the revolving stage and other large-scale revolving devices. Meanwhile, this configuration can adaptively generate a normal torque on demand by using a swinging gearbox. This relieves the friction wheels of a continuous and high-stress load, thus prolonging their workability. Also, this paper described the working principles of this new friction drive device and presented a force analysis.
Parametric Optimal Design of Robot End-Effector Tool for Robot-Assisted Automatic Polishing System
Authors: Lin Wei Yang , Du Yue , Yang Xiao Jun , Li Bing
Published: November 2010

In this paper the multi-objective optimization design of a preliminarily designed end-effector tool for robot-assisted automatic polishing system is presented. ADAMS and iSIGHT are integrated for the multi-objective optimization design, the overall procedure of which is shown in this paper. Design of Experiment is arranged before optimization. The global optimization methods provided by iSIGHT software- Exterior Penalty and Multi-Island Genetic are utilized to perform optimizing process. Simulation executed in ADAMS with model updating with optimized structural design parameters verifies the significance of the multi-objective optimization in improving the performance of preliminarily designed end-effector tool.
Structure Optimal Design of Pneumatic 6-DOF Parallel Robot Based on Natural Frequency
Authors: Wu Bo , Xu Li , Yu Xiao Dong , Wang Zhi Wei , Xu He
Published: November 2010

. In order to improve the dynamic response rapidity and positioning precision for pneumatic 6-DOF parallel robot from the structural design aspect, a mathematical model of natural frequency for the parallel robot is developed based on dynamic equation by using vibration theory. The influences of structural parameters on minimal natural frequency are analyzed by simulation and an optimization rule of structural parameters based on minimal natural frequency is proposed. The optimization rule has advantages of simplification and efficiency, which provides a new theoretical gist for optimization of structural parameters as well as for checking the results of the actual natural frequency for pneumatic 6-DOF parallel robot. And this new rule is also valuable for structural optimization design of other similar parallel robot.
Integrated Capacity Planning System for IC Backend Factory
Authors: Chen James C. , Sun Cheng Ju , Huang Po Tsang B.
Published: November 2010

Integrated Circuit (IC) manufacturing consists of four major phases - wafer fabrication, wafer probe, IC packaging, and final test. Wafer fabrication and wafer probe belong to front-end process, while IC packaging and final test belong to backend process. In this research, integrated capacity planning system (ICPS) is proposed for IC backend manufacturing by taking into account the capacity and capability of resources. This study develops integrated infinite capacity planning integrating the capacity planning of both IC packaging and final test processes to minimize the standard deviations of machine utilization and kit utilization as well as the total extra capacity requirement (as a percentage) exceeding the capacity limit of machine and kit. ICPS applies the concept of workload leveling and infinite capacity planning on dual resources. ICPS consists of five modules: Work-In-Process (WIP) Pulling Module, Lot Release Module, Resource Selection Module, Workload Accumulation Module, and Workload Balance Module. WIP-Pulling Module pulls WIP from the end of the process route to meet the master production schedule (MPS). If WIP cannot meet the MPS requirement, Lot Release Module is executed. ICPS will use Resource Selection Module to accumulate the required resource capacity along its routine at different time buckets. Workload Accumulation Module simultaneously accumulates the workload of the major resources. Workload Balance Module levels the loading of resources by adjusting the lot’s start time using these resources. ICPS is developed in Microsoft Visual Basic and industrial data are used to test its performance. The results show that ICPS is effective and efficient to balance the workload of resources for IC backend factories including packaging and final test.
The Effect of Risk Sensitivity on Collaborative New Product Development in a Supply Chain
Authors: Zhou Yu , He Rong Yao
Published: November 2010

The increasing risks and costs of new product development require firms to collaborate with their supply chain partners in product management. In this paper, a supply chain model is proposed with one risk-neutral supplier and one risk-averse manufacturer. The manufacturer has an opportunity to enhance demand by developing a new product, but both the actual demand for new product and the supplier’s wholesale price are uncertain. The supplier has an incentive to share risks of new product development via an advance commitment to wholesale price for its own profit maximization. The effects of the manufacturer’s risk sensitivity on the players’ optimal strategies are analyzed and the trade-off between innovation incentives and pricing flexibility is investigated from the perspective of the supplier. The results highlight the significant role of risk sensitivity in collaborative new product development, and it is found that the manufacturer’s innovation level and retail price are always decreasing in the risk sensitivity, and the supplier prefers commitment to wholesale price only when the risk sensitivity is below a certain threshold.
The Implementation of Sampling Plan for Optimal Inspection Allocation in Multi-Station Systems with Consideration of Rework
Authors: Rau Hsin , Wang Yi Hsiang , Cho Kuo Hua
Published: November 2010

This study explores sampling plans for optimal inspection allocation in multi-station systems with consideration of rework. After components have processed from each workstation in a serial production system, we can apply different sampling plans for inspection in order to maintain the outgoing quality level. The defective components that are detected at each sampling plan will return to the specific workstation to rework. This study proposes a minimum total cost model with a proper sampling plan after each workstation, which can help people to manager production better.
Web Oriented System Supporting Small-Medium Sized Manufacturers
Authors: Hou Jia Chen , Su Dai Zhong
Published: November 2010

. Small and medium sized manufacturing enterprises (SMEs) are challenged with the task of producing customized products in a timely and cost-effective manner. Winning competitive advantage is an imperative strategy for SMEs to compete with large sized organizations. The purpose of this research is to establish a Web oriented system to help SMEs to gain a competitive position with particular focus on the issues of product life cycle, supplier selection and product design specification. This is achieved by integrating three models, including Customer-Manufacturer-Competitor Orientation Analysis, Strategy-Position based Supplier Selection, and Component Based Partial Product Design Specification, into the system with the support of Web techniques including Enterprise Java Beans (EJB), JSP, Java Servlet, Java application, etc.
Reuse, Recovery and Recycling System of End-of Life Vehicles
Authors: Chamier-Gliszczyński Norbert
Published: November 2010

This paper presents a reuse, recovery and recycling system of end-of life vehicles, and three modules of this system are described.
Sustainable Manufacturing Oriented Prognosis for Facility Reuse
Authors: Yan Ji Hong , Hua Ding Guo , Wang Xing
Published: November 2010

Reuse is considered as one of the most reasonable strategies to realize sustainability. This paper presents an efficient methodology of ann-based prognosis combined with reliability methods to evaluate and guarantee the reusability of facility. The methodology provides the prediction of the remaining life of facility utilizing artificial neural networks. Corresponding reliability is calculated through fitting Weibull distribution to in-house time-to-failure data. Maintenance decision is made by predicting the time when the reliability or remaining life of facility reach the thresholds decided by facility’s reusability. Application results show that the proposed methodology provides effective condition information for reuse decision making from both historical and on-line perspectives.
Validation of Contact Wire Simulations on the Basis of Scaled Down Contact Wire Cutting Experiments
Authors: Özer Derya
Published: November 2010

As the requirements for overhead contact line systems increase due to higher train speeds, the need of safety equipment for these systems increases as well. Developing a component for the case of a contact wire cut to prevent further damage from the overhead contact line system requires an extensive knowledge about the system behaviour. Therefore, a comprehensive multi body system model (MBS) is developed in Matlab SimMechanics environment. In order to validate the datas generated from the simulations, a contact wire test stand has been constructed where cutting experiments can be run by releasing a pretensioned wire. Consequently, the force distribution during the contact wire cut is analyzed and these values are compared with the simulation results. For the comparisons, much attention is given to the period after the contact wire cut.
Experimental and Numerical Analysis of Residual Stresses in Additive Layer Manufacturing by Laser Melting of Metal Powders
Authors: Roberts Ibiye A. , Wang Chang J. , Stanford Mark , Kibble Kevin A. , Mynors Diane J.
Published: November 2010

Determining the three-dimensional residual stress fields and the associated distortions using numerical simulations for multi-layered parts has proved to be a challenge in additive layer manufacturing. This paper presents an innovative three-dimensional thermal-elasto-plastic finite element model for predicting the deformation and residual stress fields in TiAl6V4 parts built on steel platforms. The developed model utilises temperature dependent material physical and mechanical properties as well as latent heat of melting. Experiments conducted using surface profilometry showed good agreement with the simulation results. The finite element model was used to investigate the overall effect of the melting powder on the platform deformation and residual stresses for multiple layers of deposited powder.
A Discretion Algorithm of S-Curve Acceleration and Deceleration
Authors: Chen You Dong , Wei Hong Xing , Wang Tian Miao
Published: November 2010

A new method of sampled-data S-curve acceleration/deceleration for industrial robots and CNC machine tools was put forward, which can deal with the low velocity zone called “tail” in a deceleration zone. The equations of acceleration and deceleration were detailed, which improved the productivity by avoiding the calculation of the deceleration point at every sampled time. According to the distance of the trajectory, the trajectory can be divided into normal block, short block I type and short block II type. Aiming at each block, the equations of distance, acceleration, velocity and Jerk were given and the discrete equation of each method was presented. We have implemented our algorithm in both simulation environment and real CNC systems and conducted a series of experiments. The experimental results demonstrate that the proposed method is effective.
Selection of Artificial Boundary Condition on Soil-Structure Dynamic Interaction
Authors: Sun Hai Feng , Jing Li Ping , Meng Xian Chun
Published: November 2010

Numerical simulation is an important method to study the structural vibration response. And artificial boundary conditions will directly affect the reliability of numerical simulation results. While when we conduct numerical simulation of vibration, it is often assumed the input surface to be a fixed boundary. The purpose of this paper is to make a study on rationality of this method by the use of simulation on a two-dimensional homogeneous elastic half-space model and a soil-structure dynamic interaction model. The results show that: when fixed boundary used, after the wave reflected to the fixed boundary, it couldn’t leave the calculation region and will reflects back into the calculation region again; when viscous boundary used, the energy will be absorbed by the bottom boundary when the wave achieved the viscous boundary. It simulates the real situation that the wave goes through boundary surface into the infinite medium. So, when carrying out numerical simulation on structural dynamic analysis, the selection of fixed boundary is inclined to an incorrect result, while the select of viscous boundary is more accurate and reasonable.
The Effect of Adhesive for Fillet on Stress in Weld-Bonded Joints
Authors: You Min , Yan Jia Ling , Zheng Xiao Ling , Xiong Nan Feng , Zhu Ding Feng
Published: November 2010

The influence of the fillet with different elastic modulus on the stress distributed in weld-bonded aluminum alloy single lap joint was investigated using elasto-plastic finite element method. The results show that the peak values of the stress along the mid-bondline at the points near the fillet edge were increased as the elastic modulus of the fillet increased. But at points near the both ends of the adherend in over lap zone as well as in the region of the nugget the peak stresses were decreased except longitudinal stress Sx. The peak value of Seqv decreased first, and then it increased again as the elastic modulus in fillet increased. The load-bearing capacity of the whole weld-bonded joints may be improved for the fillet with Adhesive B (825 MPa) for the relative high stress region in nugget was wider and the stress distribution in overlap zone was more uniform.
Structural Parameter Identification Based on Equivalent Single Degree Systems
Authors: Wang Yan Wei , Wang Zi Fa , Wen Rui Zhi
Published: November 2010

In order to solve the problems of optimization algorithm used to identify the physical parameters of structures, a new method based on a series of equivalent single degree systems is proposed in this paper. The key idea of the method is that a multi-degree system can be represented by a series of single degree systems that can be identified one by one to perform the identification of the whole system. This method can not only decrease the dimensions of optimization algorithm, but also reduce the amount of estimation work in searching for the bound of parameters, and at the same time improve the identification results when parameters might suddenly change. In the numerical simulation of the physical parameter identification of a multi-degree system, Differential evolution is one of the optimization algorithm methods which are used to identify a series of equivalent single degree systems instead of the multi-degree system they represent, and the identification results prove that the method proposed in this paper is valid.
Wavelet Filter Approach for GPS Attitude Tracking System on Ship
Authors: Wang Ping , Xue Kai , Li Qiu Hong
Published: November 2010

GPS attitude tracking system on the ship is a servo mechanism which could be used for counteracting the effects of the ship’s pitch and roll. But the attitude measurement precision of ship is more important to the tracking precision of the servo mechanism. As one of the major error sources, the noises of GPS attitude measurement bring out the steady tracking error of the tracking servo mechanism. To reduce the steady error due to the noise, the threshold noise removing method of wavelet is used to eliminate the noise. And the better result with the meaning of standard deviation and the better visual effects could be gotten by using the method. The signals of the processed high frequency and the retained low frequency could be reconstructed with the original signals. Therefore, the signals after noise removing could be obtained. The threshold noise removing method of wavelet used to remove the noise of GPS attitude information in the paper is of great value in practice.
Dynamic Analysis of Frame Structure Using Nonlinear Stochastic Finite Element Method
Authors: Zhen Li , Qing Wang
Published: November 2010

The objective of this paper is to propose an algorithms and a frame work of perturbation-based stochastic finite element method for large variation nonlinear dynamic problem of ship frame structure. For this purpose, based on the principle of stochastic virtual work some algorithms and a framework related to stochastic finite element method have been studied. To prove the validity and practicality, a numerical example for nonlinear dynamic problem with large variation was calculated to compare with Monte-Carlo simulation method. The results showed that the approaches proposed herein are feasible and effective for the nonlinear dynamic analysis of structures with random parameters.
Project Based Learning in International Teams – Monitoring the Effectiveness of Teamwork
Authors: Ashworth David W.C.
Published: November 2010

Students working on semester-long projects in international teams, such as the European Project Semester programme at the Ingeniørhøjskolen i København – University College (IHK), face many challenges, not the least of which is communication between different cultures. The supervisor pays a key role in supporting a project team and monitoring its effectiveness. One of the key tools employed is a self and peer review assessment, undertaken twice by each team member during the semester. The assessment considers the quantity and quality of the contribution made by each team member and their participation in teamworking activities. The supervisor uses the assessment to monitor teamworking and to give constructive feedback and advice where needed. Comparison of the responses from self and peer review assessments was undertaken and the findings are presented. Limited results over a 3 year period were analysed and compared with Autumn 2009 semester results and conclusions drawn.
Tracking Error Transform in Parallel Kinematic Machining
Authors: Amirian Ghasem , Schenck Christian , Kuhfuss Bernd
Published: November 2010

Parallel kinematic machine tools (PKM) are developed to increase dynamic parameters for high speed and high accuracy machining to gain short lead times and high productivity. One of the most important components of machine tools is the numerical controller (NC). Most NCs are organized in a cascaded structure, comprising the position, velocity and current loops. Commonly applied servo controllers generate tracking errors in each axis. These tracking errors are a significant factor that affects machining accuracy, beside geometric machine errors, vibrations, temperature changes and tool errors. In this paper the contour error originated from servo tracking controller in Cartesian kinematic machine tools (CKM) with perpendicular arranged machine axes and PKM is presented. The effects of the forward transformation of the tracking errors in PKM are addressed with experiment and simulation results. The servo tracking effect on trace accuracy is discussed by a tripod mechanism and radial deviations are measured with double ball bar method (DBB).
Electron Transportation and Recombination in TiO2 Film for Flexible Dye-Sensitized Solar Cell
Authors: Lin Hong , Zhao Xiao Chong , Liu Yi Zhu , Li Xin , Li Jian Bao
Published: November 2010

Research on the flexible dye-sensitized solar cells (DSCs) has been more and more extensively conducted during the recent years both academically and comercially for the sake of its further reduced expense and even broader application. However, significant promotion of electron transport properties and consequently the photovoltaic performances of such devices are perpetually hindered by the key problem that the poor heat tolerance of the plastic substrates employed in flexible DSCs makes high-temperature sintering of the photoanode films impossible. Based on a brief overview of the current state of research on flexible DSCs, including new materials and delicate processing techniques, and the research results from the author’s own group, this chapter specially treats the profound mechanistic issue of electron transport and recombination in flexible DSCs, which is rarely discussed and relatively less well understood up to now. It is pointed out that the electron transport and recombination dominate photovoltaic performance of the flexible DSCs and suppressing the recombination of injected electrons with electrolyte redox species is of crucial sense for performance promotion. Besides, the methods for restraining electron recombination are proposed and the developing trend and prospects of flexible DSCs are also presented.
Investigation of PEO-Imidazole Ionic Liquid Oligomer and Polymer Electrolytes for Dye-Sensitized Solar Cells
Authors: Lin Yuan , Wang Maio , Xiao Xu Rui
Published: November 2010

Ionic liquid oligomer, 1-oligo(ethyleneoxide)-3-methylimidazolium salt　(PEO(X)MIm) and Ionic liquid polymer, poly(1-oligo (ethylene glycol) methacrylate-3-methylimidazolium) salt (P(MOEMIm)) prepared by incorporating imidazolium ionic liquid with PEO oligomer and polymer were investigated as electrolytes for dye-sensitized solar cells (DSCs). Ionic liquid electrolytes were composed of LiI, I2, and PEO(X)MImCl or the mixture of 1-hexyl-3-methylidazolium iodide (HMImI), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) and PEO(X)MImCl. Quasi-solid-state electrolytes were prepared by employing the imidazole polymers P(MOEMImCl) to solidify the liquid electrolyte containing lithium iodide, iodine and ethylene carbonate (EC)/propylene carbonate (PC) mixed solvent. Ionic liquid based quasi-solid state electrolytes were prepared by solidifying the ionic liquid electrolytes containing HMImI or a binary mixture of HMImI and EMImBF4 with an ionic liquid polymer P(MOEMImCl), respectively. The influences of PEO molecular weight, polymer content, addition of alkyl ionic liquid and various anions of the ionic liquid oligomers and polymer on the ionic conductivity, apparent diffusion coefficient of the redox species in the electrolytes and the performance of solar cells were examined. The influences on the kinetic behaviors of dye regeneration and triiodide reduction reactions taken place at nanocrystalline TiO2 electrode and Pt counter-electrode, respectively, were also studied by cyclic-voltammetry and electrochemical impedance spectroscopy measurements. By using ternary ionic liquid electrolyte containing 1M lithium iodide and 0.5M iodine in the ionic liquid of the ionic liquid mixture of PEO(X)MImCl), HMImI and EMImBF4, quasi-solid-state electrolytes and ionic liquid based quasi-solid state electrolytes the photoelectron conversion efficiency of DSCs is 7.89%, 7.6% and 6.1%, respectively(AM 1.5, 100mWcm−2). These results show the potential application of PEO based ionic liquid in SCs.
Research Progress of the Counter Electrode in Dye-Sensitized Solar Cells
Authors: Tang Ying Tong , Pan Xu , Dai Song Yuan , Zhang Chang Neng , Tian Huan Jun
Published: November 2010

This review covers recent research on counter electrodes using platinum (Pt), carbon and conducting polymers as catalysts for the reduction of triiodide in the dye-sensitized solar cell. Different types of counter electrode preparation methods and their advantages and disadvantages are compared. The inadequacy of the counter electrode with the precious metals and the advantages of the non-metallic-type counter electrode are pointed out. Especially, recent research on the Pt counter electrode in our group is discussed concerning with the reaction mechanism of the triiodide (I3-)/ iodide (I-) redox couple on the Pt counter electrode.
Efficiency of Electron Injection in Dye-Sensitized Semiconductor Films
Authors: Katoh Ryuzi , Furube Akihiro
Published: November 2010

The efficiency of electron injection (inj) in dye-sensitized nanocrystalline films has been studied by means of transient absorption spectroscopy. We observed inj of nearly unity for N3 dye adsorbed on nanocrystalline TiO2 films (N3/TiO2). We examined the effects of various experimental conditions, such as light intensity, excitation wavelength, and presence of additives (4-tert- butylpyridine, tBP and Li ions), on inj. We also used various semiconductors and sensitizer dyes to study the effect of free energy change (G) on inj. These results give us new insights for developing high-performance solar cell devices.
Indentation Size Effect and the Hall-Petch ‘Law’
Authors: Brown L.M.
Published: November 2010

The flow of material out from under regions in compression must occur by the operation of many slip systems, which together produce rotational flow. Such flow requires the accumulation of geometrically necessary dislocations, and leads to the indentation size effect: smaller indents produce higher hardness, a component of the hardness being inversely proportional to the square-root of the indenter size. A pattern of flow in polycrystals which satisfies both continuity of normal stress and continuity of matter at boundaries can be achieved by rotational flow, and it leads to a grain-size effect. Under most circumstances, the flow stress has a component which is inversely proportional to the square-root of the grain size, the Hall-Petch law. The flow is accompanied by the build-up of internal stress which can be relieved by intercrystalline cracking, thereby limiting the cohesive strength of polycrystals. The relationship between these ideas and traditional views is briefly explained, and an analysis is given of recent experimental results.
Indentation of Ceramics, Some Highlights
Authors: Le Bourhis Eric
Published: November 2010

Contact mechanics is widely used to explore the mechanical properties of brittle materials while it rules the mechanical performance of industrial pieces. Elastic, plastic and brittle responses can be investigated and are highlighted. The indentation plastic zone can be decomposed into a central highly strained zone and rosette arms. The evolution of the central zone extension can be predicted by Johnson’s cavity model obtained under full load while on the other hand rosette arm extension is to be modeled considering the residual stresses from the indentation. Upon a post heat treatment, further development is obtained both experimentally and theoretically. Using large loads, elimination of cracks can be achieved using higher temperature to pass the brittle-ductile transition.
Fivefold Twin Center in CVD Diamond Film
Authors: Huang Yuan Sheng , Luo Cheng Ping , Qiu Wan Qi , Liu Hong Wei
Published: November 2010

The microstructure and crystallographic characteristics of diamond film deposited with the chemical vapor deposition method was investigated using transmission electron microscopy (TEM). It is found that fivefold twin center does not always behave as growth nuclei of diamond grain. For those behaving as growth nuclei, there are a large amount of defects in every block of fivefold twin. However, for those not behaving as growth nuclei, two blocks of fivefold twin contain large quantities of defects, the other three are nearly clear. High resolution TEM analysis shows stacking faults coexist with microtwins in the two vast-defects-contained blocks. The effect of the mismatch angle (7.5°) in fivefold twins on microtwins, and the coexistence mechanism of both stacking faults and microtwins are also discussed.
Effects of Vacancies on the Thermal Expansion of Mercury Indium Telluride Crystals
Authors: Wang Ling Hang
Published: November 2010

The thermal expansion of a novel semiconductor material, mercury indium telluride (MIT) grown by vertical Bridgman (VB) method, was measured from room temperature till 573K by two methods, i.e. Macroscopic dilatometric and X-ray measurements. It is found that the macroscopic expansion is quite different from the expansion of the lattice (micro-expansion). The macroscopic expansion is lower than micro-expansion in the temperature range of 303-425.5K and has a minimum of -0.14% linear expansion, while the macro-expansion becomes larger than micro-expansion in the temperature higher than 425.5K. The former may be due to the effects of the existing neutral vacancies. The latter may result from the influence of thermal-activated vacancies on the lattice.
Fabrication Multi-Layer Polymer Microstructures by X-Ray Lithography with Alignment
Authors: Li Yi Gui , Sugiyama Susumu
Published: November 2010

Poly(methyl methacrylate)(PMMA) and Poly L-lactic acid (PLLA) are transparent and they are suitable for optical purposes. The multi-layer polymer microfabrication can be applied for a large displacement actuator and precision sensors. A new method is intruduced to generate the multi-layer polymers microstructures by X-ray lithography with alignment. The function of X-ray on polymer materials are breaking the polymer main chain and generating intermediates which can be degraded further and finally dissolved by the solvent interaction. The method for polymer micromachining by using X-ray lithography with alignment for fabrication multi-layer micro polymer structures is confirmed experimentatively.
Influence of the Sputtering Pressure on the Properties of TAZO Films Prepared by DC Magnetron Sputtering
Authors: Liu Han Fa , Yuan Chang Kun
Published: November 2010

Transparent conducting Ti-Al co-doped zinc oxide films (TGZO) with high transparency and relatively low resistivity have been successfully prepared on water-cooled glass substrate by DC magnetron sputtering at room temperature. All the deposited films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate. The Ar sputtering pressure was varied from 1.5 to 13 Pa. The electrical resistivity decreases when the sputtering pressure increases from 1.5 to 7.5 Pa. The electrical resistivity increases when the sputtering pressure increases from 7.5 to 13 Pa. When the sputtering pressure is 7.5 Pa, it is obtained that the lowest resistivity is 2.18×10-4Ω⋅cm. In the visible region, all the deposited films show a high average transmittance of above 92 %.
Triply-Responsive Poly(N,N-Dimethylaminoethyl Mathacrylate) with an Azobenzene Moiety
Authors: Tang Xin De , Wang Xin , Dou Yuan Yuan
Published: November 2010

A serious of triply-responsive poly(N,N-dimethylaminoethyl methacrylate) (PMAEMA) containing an azobenzene group as the terminal group were synthesized by atom transfer radical polymerization (ATRP). The ATRP process of DMAEMA was initiated by an azobenzene derivative substituted with a 2-bromoisobutyryl group (Azo-Br) using CuCl/Me6TREN as catalyst and the mixture of DMA and H2O (v/v = 3:1) as solvent. The molecular weights and their distributions of the resulting homopolymers (Azo-PDMAEMA) were characterized by gel permeation chromatography (GPC). The polymers are soluble in aqueous media and exhibit a lower critical solution temperature (LCST) that alternated reversibly in response to pH and photoisomerization of the terminal azobenzene moiety. It was found that the LCST increased as pH decreased in the range of testing. Under UV light irradiation, the trans-to-cis photoisomerization of the azobenzene moiety resulted in a higher LCST, while it recovered under visible light irradiation.
Study on Surface Coating of BaO- B2O3-SiO2 Glass-Ceramic Powders with Al2O3 for Water-Based Tape Casting
Authors: He Yan , Cui Xue Min , Liu Le Ping , Liang Zhong Yuan
Published: November 2010

This paper studied the low temperature co-fired ceramic (LTCC) powders based on BaOTiO2- B2O3-SiO2 glass-ceramics that is coated with Al2O3 using co-precipitation process. The Al2O3 coating is made from aluminum isopropoxide precursor solutions. Atomic Absorption spectrometer and TEM methods are employed in this experiment. After calcinations, the alumina coating is strongly adhered to the LTCC particles’ surface. The Al2O3 coating is able to prevent soluble Ba2+ from dissolving in water and the effect grows with the increasing mass fraction of aluminum isopropoxide precursor in the co-precipitation system. The optimum mass fraction of alumina isopropoxide coating precursor is about 6wt%.
Study on Theoretical Basis and Process Optimization for Solar Grade Silicon Fabrication
Authors: Gao Yong Chao , Zhao Bai Tong
Published: November 2010

As solar energy is inexhaustible, solar cells have become one of the options to the future energy. The raw material silicon as one of the Earth's most abundant resources elements, have the advantage of non-toxic, no pollution, no radiation, high photoelectric conversion efficiency, stability and reliability of optical performance become the main raw material for production of solar cells. Because of its supply is limited, We used relatively inexpensive metallurgical grade silicon as a starting material to produce solar grade silicon for solar cells is considered relatively inexpensive method. Therefore, the removal of impurities from metal silicon witch reduce solar cell carrier lifetime and thus reducing its power generation efficiency is a significant issue. To this end, according to impurities in molten silicon and solid silicon demonstrated various characteristics and existence forms, in this paper we used acid leaching, directional solidification, electron and magnetic field, vacuum melting, blow reactive gases and so on to fabricate solar grade silicon from metal silicon in theory to analyze and optimize process.
Spectral Properties of Spatially and Spectrally Partially Coherent Pulsed Beams in Fused-Silica Glass Medium
Authors: Ding Chao Liang , Teng Min , Zhao Zhi Guo , Pan Liu Zhan
Published: November 2010

Using the coherence theory of non-stationary fields and the method of Fourier transform, the spectral properties of spatially and spectrally partially coherent Gaussian Schell-model pulsed (GSMP) beams in fused-silica glass medium are studied and analyzed numerically. It is shown that the spectral shift takes place, which depends on the position of the field point, spatial correlation length, temporal coherence length and dispersive property of medium, as GSMP beams propagate in fused-silica glass medium. The on-axis spectrum is blue-shifted, and the relative spectral shift increases with increasing propagation distance, and decreases as the spatial correlation length and temporal coherence length increases, and then approaches an asymptotic value. The dispersive property of medium plays an important role in the spectral properties of spatially and spectrally partially coherent beams.
Fabrication of 1-3 Type Multiferroic Nanostructured Composite Films by Chemical Methods
Authors: Zeng Xia , He Xi Yun , Sun Da Zhi , Cheng Wen Xiu , Qiu Ping Sun , Zheng Xin Sen
Published: November 2010

A new process was developed for fabrication of multiferroic 1-3 type nanostructured composite films. In this process, eletrodeposition method was adopted to prepare the arrays of cobalt nanowires as ferromagnetic composition. The images, phase structure and magnetic properties were characterized by SEM, XRD and VSM, respectively. The results showed that applying magnetic field during electrodepostion process could improve the alignment and height uniformity of nanowires arrays, inducing (002)-orientation growth. The PZT (53/47) precursor solution prepared for ferroelectric composition was infiltrated the spaces between nanowires. After annealed at 700 °C for 20 min, the 1-3 type multiferroic composite film was achieved. Preliminary results show this technique to have the potential to become a practical fabrication process for 1-3 type multiferroic composite films.
Modified Rod in Tube Technique for Fabrication of Tellurite Glass Preforms
Authors: Liao Gui Hua , Xing Jian Jun , Chen Qiu Ling , Chen Qiu Ling
Published: November 2010

A modified rod in tube technique for tellurite glass preform fabrication is reported, and the effects of the fabrication process on the preform quality are discussed in terms of different processing factors. The conditions for obtaining good quality of reproducible preforms were experimentally investigated. Preforms with a good interface between core and cladding were obtained by this technique, then drawn to fiber.
Effect of the Type of Alcohol on the Properties of ZnO Nanopowders Prepared with Solvothermal Synthesis
Authors: Wang Yan Xiang , Sun Jian , Yu Xi
Published: November 2010

ZnO nanopowders were prepared via solvothermal synthesis by using methanol, ethanol, isopropanol, n-butanol, n-hexanol and 1-octanol as the reaction medium. Effects of alcohol on the properties of the ZnO nanopowders were investigated. XRD, FSEM and UV-visible absorption spectroscopy were used to characterize ZnO nanopowders. The results show that: the type of alcohol had significantly effect on the morphology of ZnO nanopowders. ZnO nanoparticles with diameter ~100 nm were obtained by using ethanol and isopropanol as reaction solvent. ZnO nanorods were obtained with the n-butanol, n-hexanol and 1-octanol as reaction solvent, and the grain size distribution broadened with the increasing of carbon chain of alcohol. The effect mechanism of alcohol was also discussed in detail.
Bulk PZT Thick Film Preparation on Silicon Wafer and its Application for MEMS Power Generator
Authors: Tang Gang , Liu Jing Quan , Li Yi Gui , Liu He Sheng , Yang Chun Sheng , He Dan Nong , Dao Viet Dzung , Tanaka Katsuhiko , Sugiyama Susumu
Published: November 2010

The paper reports on the PZT thick films preparation method by bonding bulk PZT on Si and then lapping PZT to suitable thicknesses. Epoxy resins with preferable thermostability were used as the intermediate adhesive layer in bonding process. A tight bonding of more than 10MPa was attained at suitable gradient bonding temperatures in an oven which were from 30 oC up to 105 oC according to 15 oC per thirty minutes and holding for more than 3h at 105 oC, and a pressure of more than 0.05MPa. Some properties of the prepared PZT thick films were tested. Finally, a piezoelectric MEMS power generator was fabricated by using the described techniques of PZT thick films preparation on silicon. The maximum output voltage under the resonant operation was measured.
Controlled Synthesis of Fe3O4 Nanosheets via P123 Micelle Template
Authors: Sun De Hui , Sun De Xin , Hao Yu
Published: November 2010

Magnetic iron oxide nanomaterials (e.g. Fe3O4 and γ-Fe2O3) with different morphologies have aroused extensive attention due to their fundamental research and potential technological applications such as magnetic recording media, magnetic fluids and magnetic drug-targeting. In this article Fe3O4 nanosheets were successfully synthesized using triblock copolymer (PEO)20(PPO)70(PEO)20 (P123) micelles as structure-directing agents in the presence of surfactant-assisted ethylene glycol (EG) and precipitator hexamethylenetetramine (HMTA) at 70 °C for 2 h in N2. The Fe3O4 nanosheets have irregular shape with thickness of the Fe3O4 nanosheets about 10-15 nm. The X-ray diffraction (XRD) pattern confirms the Fe3O4 nanosheets have magnetite structure and its nine distinguishable diffraction peaks can be perfectly indexed to the (111), (220), (311), (222), (400), (422), (511), (440), and (533) planes of the fcc structure of magnetite. Its saturation magnetization (σs) is 58.4 emu/g. The possible formation mechanism of the Fe3O4 nanosheets in present work is proposed.
Preparation of the Kondo Insulators FeSi by Magnetron Sputtering
Authors: Zhang Jin Min , Xie Quan , Borjanović Vesna , Liang Yan , Zeng Wu Xian , Fu Da Peng , Ma Dao Jing , Wang Yan
Published: November 2010

The Kondo insulator FeSi was prepared by DC magnetron sputtering and the effects of sputtering parameters on the formation of FeSi were investigated in detail. The formation of monosilicide FeSi was clarified using X-ray diffraction (XRD) and its microstructure was characterized by scanning electron microscopy (SEM). The results indicate that the sputtering gas pressure, the sputtering power and the Ar flux all have significantly effects on formation of FeSi and the crystalline of the film. The sputtering gas pressure has effects on sputtering yields, depositing rate and the energy of sputtering atoms, the sputtering power has effects on the kinetic energy and the diffusion ability of deposing atoms and the gas flux has the effects on the flowing state of Ar gas. The most optimal sputtering parameters for the preparation of the Kondo insulator FeSi by DC magnetron sputtering are given: 1.5 Pa for sputtering Ar pressure, 100 W for sputtering power and 20 SCCM for sputtering Ar flux.
Influence of Polarization on the Spectral Changes of Stochastic Electromagnetic Pulsed Beams
Authors: Pan Liu Zhan , Ding Chao Liang , Zhao Zhi Guo , Yuan Xiao
Published: November 2010

An analytical expression for the spectrum of stochastic spatially and temporally partially coherent electromagnetic Gaussian Schell-model pulsed (GSMP) beams is derived, and used to study the spectral changes of electromagnetic GSMP beams in free space. The influence of polarization on the on-axis relative spectral shift is emphasized. It is shown that the on-axis relative spectral shift increases with increasing the degree of polarization of source P0 for the case of δxx≠δyy, i.e. the spatial coherence length δxx of x component of the electric field at the source is not equal to that of y component. For δxx=δyy or δxx→∞ and δyy→∞, the on-axis relative spectral shift is independent of P0.
Measurement of Absorption Spectrum of Media by Grating Spectrometer
Authors: Liu Han Chen , Yan Xiang An , Zhu Chang Jun , Xia Cai Juan , Yu Hua Wa , Wu Jun Fang , Xu Guang Shen
Published: November 2010

In order to measure quantum yield (quantum efficiency) of light in the research of fluorescence excitation, rapid prototyping of micro-structure and photochemical, the absorption spectrum must be precisely measured. Therefore, the reflection on optical media interface, absorption and transmission in the medium must also be considered. In this article, we exhibit a set of reasonable experimental method which is designed to measure absorption spectrum by grating spectrometer. The results show that the obtained absorption lines are properly reliable if we select an appropriate way to settle the sample. Furthermore, it can be well generalized and applied to the selection of fluorescence excitation spectrum, photochemical reaction spectrum, photoelectric device spectrum.