bluuebunny/crossref_metadata_2025 huggingface dataset:
A Continuum Theory for Simulation of Ionic-Strength-Sensitive Hydrogel for BioMEMS Application
Authors: Lai Fu Kun , Li Hua
Published: September 2009

A continuum multiphysics theory is presented for simulation of the ionic-strength-sensitive hydrogel and surrounding solution. The theory considers the coupled effects of chemical, electrical and mechanical multi-energy domains on the swelling behavior of the ionic-strength-sensitive hydrogel and is thus termed the multi-effect-coupling ionic-strength-stimuli (MECis) model. The MECis model consists of several governing equations, including Nernst-Planck flux system, Poisson equation, fixed charge density and mechanical equilibrium equation, in which the effect of the ionic strength is incorporated into the governing equation of diffusive flux and fixed charge. The theory is capable of simulating the swelling/shrinking behavior of smart hydrogel in buffer solution subject to the change in the ionic strength, and providing the distribution of the ionic concentration and electrical potential for applications of BioMEMS design. Apart from the ionic strength as the main stimulus, the influence of several parameters is discussed in detail, including the initial fixed charge density and Young’s modulus of the hydrogel.
Microstructure and Magnetic Properties of Rapidly Solidified Ni2(Mn,Fe)Ga Heusler Alloys
Authors: Prasad R.V.S. , Manivel Raja M. , Phanikumar G.
Published: September 2009

This study reports detailed microstructural and magnetic characterization of rapidly solidified Ni2(Mn,Fe)Ga heusler alloys processed using the melt spinning technique. Series of Ni50Mn(25-x)Fe(x= 2, 5, 8, 11)Ga25 alloys were prepared by vacuum arc melting and then melt spun at constant wheel speed of 20 m/sec to obtain samples in the form of ribbons. X-ray diffraction analysis of as-cast Ni2(Mn,Fe)Ga alloy with different ‘Fe’ concentrations revealed austenite phase with L21 Heusler atomic order at room temperature. Transmission electron microscopy of melt spun ribbons reveals a precursor tweed structures due to magnetic tweed contrast when the ‘Fe’ concentrations are 8% and 11%. In case of 11% ‘Fe’ substituted alloy martensite phase was found to from at the grain boundary triple junctions. Thermo magnetic measurements determine that, as the ‘Fe’ concentration increases from 2 to 11%; it enhances the magnetic transition temperature from 375 to 403 K.
Evolutionary Algorithm Based Feedforward Control for Contouring of a Biaxial Piezo-Actuated Stage
Authors: Lin Chih Jer , Chen Shu Yin
Published: September 2009

The main objective of this paper is to establish a precision contouring control of a biaxial piezoelectric-actuated stage. The positioning accuracy of the piezoelectric-actuated stage is limited due to the hysteretic nonlinearity of the piezo-electric actuators (PEA). To compensate this hysteresis problem, a feedforward controller based on an evolution algorithm is proposed. The dynamics of the hysteresis is formulated by the Bouc-Wen model and the evolutionary algorithms (EAs) are studied to identify the optimal parameters of the Bouc-Wen model. To verify the consistency, two micro-contouring tasks are implemented by the proposed feedforward controller with the feedback of linear optical scales in DSP based real-time control architecture.
Design and Fabrication of a MEMS-Based Gas Sensor
Authors: Yoon Jin Ho , Kim Jung Sik
Published: September 2009

In this study, the micro gas sensor for NOx gas was fabricated by using a MEMS technology and sol-gel process. The sensing electrode and micro heater were designed to be a co-planar typed structure in the Pt thin film layer. The fabricated micro platform had a low power consumption of 67 mW at 2.0 V of heater voltage and 300°C of operating temperature. Indium oxide as a sensing material for NOx gas was synthesized by a sol-gel process with indium isopropoxide. The particle size of synthesized In2O3 was identified as about 50 nm. The maximum gas sensitivity as relative resistance (Rs = Rgas / Rair) occurred at 300°C with the value of 8.0 at 1 ppm NO2 gas. The present study shows that a MEMS-based gas sensor is a potential candidate for the automobile AQS (air quality system) gas sensor with many advantages of small dimension, high sensitivity, short response time and low power consumption.
Analysis of In-Phase Coupling Error in the Vibratory MEMS Gyroscope with Various Vacuum Degrees
Authors: Zhou Wen Wen , Chen Zhi Yong , Zhou Bin , Zhang Rong
Published: September 2009

This paper presents mechanism and sources of in-phase coupling error (i.e. bias drift) in a micromachined silicon vibratory gyroscope with various vacuum degrees. Based on a detailed analysis of squeeze-film and slide-film dampings acting on each area of the mass and coupling approaches from drive mode to sense mode, the expression of coupling air damping forces were obtained. Another fact causes the drift of in-phase coupling error is, the phase of sense mode varies with the air pressure and can produce error if the demodulation phase is fix. The experiment measuring coupling error has been performed with various vacuum ranging from 7.5 mtorr to 1 atm, which indicated that in-phase coupling force is very limited and can be significantly reduced by lower the air pressure. Comparison of the theoretical and the experimental pressure-bias relation demonstrated that the change of the phase of sense mode is the dominant factor of bias drift with the change of air pressure.
Microfluidic Devices Fabricated by LTCC Combined with Thick Film Lithography
Authors: Yoon Young Joon , Choi Jae Kyung , Lim Jong Woo , Kim Hyo Tae , Kim Ji Hoon , Choi Youn Suk , Lee Jong Heun , Kim Jong Hee
Published: September 2009

Low temperature co-fired ceramic (LTCC) process combined with thick film photolithography was employed to fabricate ceramic-based microfluidic devices. To check the applicability of novel process, three types of passive mixers, diffusion-driven T-type mixers with different channel width and convection-driven chaotic mixer, were fabricated and their microfluidic performance was evaluated. It was confirmed that the degree of mixing in ceramic-based microfluidic passive mixers was well matched with the numerical simulation data.
Characteristics of Biodegradable Implantable Drug Delivery System with Micro-Porous Structure
Authors: Gao Yang , Wang Xiao Peng , Chen Tian Ning
Published: September 2009

To eliminate the release-delayed phenomenon of macromolecular drug delivery system at the early stage, biodegradable implantable drug delivery system with micro-porous structure was designed by Bio-MEMS technology in this paper. Water absorption and degradation characters of polylactic acid - polyglycolic acid (PLGA) material with different monomer ratio were studied. Drug release model was built by mass transfer equation and the Finite Element Method. Influencing factors about the cumulative amount of release drug were analyzed. And the results suggest that with more ratio of polylactic acid(PLA), PLGA would have more greater amount of water absorbed as well as a longer degradation time. Better linearity of cumulative amount of release drug would be achieved by reducing the diameter and number of micro-porous.
Tunable Optical Filter by Thermal Effect Based on MEMS Technology
Authors: Zhang Wu , Tao Ji Fang , Zhu Wei Ming , Cai Hong , Liu Ai Qun
Published: September 2009

In the broadband communication network, the wavelength-division-multiplexed (WDM) system is widely used to maximize the information that the signals can carry. As a result, the number of channels which are carried by different optical wavelengths in the WDM optical fiber network also keeps increasing. To separate the huge number of different wavelength signals, optical filter is required. The optical filter based on semiconductor has been widely studied due to the maturation of semiconductor fabrication technology and that it is possible to integrate the filter with the stable semiconductor devices such as laser diodes and MOSFETS.

The tunable optical filter is basically a selective optical resonator that only allows the resonant modes passing through. Various mechanical methods are studied to achieve the tunable effect by tuning the physical structure of the filter; however, there is not much research on how the semiconductor material will affect the tuning function. In this paper, the author studied the influence of refractive index of the multi-silicon-slabs on the filter, whereby the tuning of refractive index is reached by thermal effect. It is found by simulation that when heating the silicon slabs, the increasing refractive index of silicon will lead to a shift of the resonant mode wavelength. This shift is almost linear with the change of the temperature, which is about 1nm with every 20K temperature increase. For certain devices, the result of the simulation showed it is possible to tune the resonant mode from C band to L band in the Fiber Optical Communication.
A Liquid Optical Tip via Control of Flow Rate
Authors: Yang Yi , Liu Ai Qun
Published: September 2009

Efficient energy interconversion between light propagation and the localized field of light is important for highly-sensitive biological and chemical detectors. Solid optical tip can effectively enhance optical intensity for the measurement of nanoscale single molecule imaging. However, it lacks dynamic control mechanisms and is difficult to realize a smooth interface which may result in serious loss of scattering. Liquid can be dynamically controlled and the interfaces are optically smooth. Recently, liquid waveguides are reported to exhibit various advantages of dynamic, cheap and low optical loss. In this paper, a liquid optical tip in a microchannel controlled by flow rates is reported. In the design of the optofluidic chip, the core flow stream of the liquid waveguide is formed as Calcium Chloride (CaCl2) flow stream, and the cladding flow stream is formed as dioionzed (DI) water flow stream. The diffusion of CaCl2 between the microfluidic laminar flows establishes a gradient refractive index distribution to make an optical tip. For the optical system, laser source with central wavelength of 633 nm is used as input. The microchannel has a height of 80 µm and a width of 100 µm. The diffusion coefficient is 1 × 10-9 m2/s. The original refractive index of CaCl2 solution and deinized (DI) water are 1.442 and 1.332, respectively. The optical intensity at the optical tip is increased by 15 times sing Finite-Difference Time-Domain (FDTD) method. Thus, light be guided to form a sharp optical tip through the control of liquid. The on-chip optical tip has potential applications in biological, chemical and medical solution detectors.
The Design and Fabrication of Poly(dimethylsiloxane) Single Mode Rib Waveguides for Lab-on-a-Chip Applications
Authors: Poenar Daniel Puiu , Kee Jack Sheng , Neuzil Pavel , Yobas Levent
Published: September 2009

This paper reports on the design and fabrication of Poly(dimethylsiloxane) (PDMS) single mode rib waveguide. PDMS was chosen as the base material for both the core and cladding of the waveguide. Such a PDMS waveguide allows an easy integration with microoptical components for lab-on-a-chip systems fabricated by soft lithography fabrication methods. The modification of the PDMS refractive index was achieved by diluting the base material with hexane. The fabricated PDMS rib waveguides were characterized for mode profile characteristics and the results confirmed the excitation of the waveguide's fundamental mode. The propagation loss was characterized at a wavelength of 635 nm and found to be 0.48 dB/cm. Such a low loss waveguide is useful as basic building block for complex microphonotnics device.
A THz-Wave Generator Based on MEMS Technology
Authors: Tao Ji Fang , Zhu Wei Ming , Cai Hong , Wu Jian , Xu Kun , Lin Jin Tong , Liu Ai Qun
Published: September 2009

This paper reports a new kind Terahertz generator using tunable dual-wavelength generator based on MEMS technology, which are developed based on free-carrier effect (FCE) and thermo-optic effect (TOE) [1-3]. The approach provides a wide tuning range from 0 to 15 nm by adjusting the current of laser diodes and heating up common silicon Fabry-Perot (FP) external cavity. Compared to the conventional optical generation methods, this method has fast tuning speed (<1 ms), small size (2.2 mm 0.8 mm), high integration and quite stability performance.
A Photonic MEMS Polarization Switch
Authors: Zhu Wei Ming , Zhang Wu , Cai Hong , Bourouina Tarik , Liu Ai Qun
Published: September 2009

This paper presents a photonic polarization switch based on microelectromechanical systems (MEMS) technology. The polarization switch can change the pathway of the different polarized light via optical tunneling effects. By controlling the incident angle of the input light, the output polarization state can be switched between two different polarization states. The polarization switch has promising applications on both photonic circuit and bio-detecting.
Study on the Pretreatment Process for Nickel Coating on Microspheres
Authors: Liang Zhen Fang , Zhao Yan , Duan Yue Xin
Published: September 2009

Pretreatment process for electroless nickel coating on ultrafine glass microspheres with an average diameter smaller than 10μm was studied. Through comparative experiments, three-step pretreatment process including washing, coupling and activating was selected to pretreat ultrafine glass microspheres with supersonic. Then the amount and distribution of palladium activate sites absorbed on the surface of microspheres were measured by energy-dispersive X-ray spectroscopy (EDX). It was found that the content of palladium was increased obviously because of addition of coupling treatment and optimization of pretreatment parameters such as agitation method and loading weight, meanwhile palladium was distributed more uniformly due to the action of supersonic. In addition, pretreated microspheres were placed in an alkaline plating solution with supersonic and nickel coated microspheres were obtained. Then morphology and composition of the coating were characterized by scanning electron microscopy (SEM) and EDX. The results proved that EDX results of palladium could characterize the result of pretreatment effectively. The low density Ni coated microspheres may be utilized for manufacturing conducting materials for EMI shielding applications.
Effect of the Coolant Lubricant Type and Dress Parameters on CBN Grinding Wheels Performance
Authors: Tawakoli Taghi , Rasifard Abdolreza , Vesali Alireza
Published: September 2009

The efficiency of using of CBN grinding wheels highly depends on the dressing process as well as on the coolant lubricant used. The Institute of Grinding and Precision Technology (KSF) investigated the performance of vitrified CBN grinding wheels -being dressed using different parameters- while using two different grinding oils and two different water-miscible coolant lubricants. The obtained results show that the performance of the vitrified CBN grinding wheels regarding the quality of the workpiece surface, the grinding forces as well as the wear of the grinding wheel, highly depend on the dressing conditions and the type of the coolant lubricant used. Compared to the water-miscible coolant lubricants, the grinding oils show better results.
Dressing Behaviors of PCD Conditioners on CMP Polishing Pads
Authors: Tsai M.Y. , Sung James C.
Published: September 2009

Diamond pad conditioner or dresser can determine the efficiency of chemical mechanical polishing (CMP) processes and the quality of polished wafers. Conventional diamond pad conditioners are made by adhering discrete diamond grits on a flat substrate. The size distribution of diamond grits coupled with the deformation of the substrate often make the tips of diamond grits lying at different heights. Instead of attaching individual diamond grits to a metal substrate, a revolutionary design of pad conditioners is based on carving a structure out of sintered polycrystalline diamond (PCD) matrix. The PCD dresser is manufactured by wire electro discharge machining to form cutting pyramids of a specific size with a designed shape. The dressing characteristics of pad surface textures are studied by comparison with conventional diamond pad conditioner. Experimental results indicate that the PCD dresser can dress asperities of the pad more uniformly than the conventional diamond dresser due to PCD dresser having identically shaped tip and the same height diamond. In addition the cutting rate of PCD dresser for IC1000 pad not only is reduced by about 30% but also it can dress pad more effectively than conventional diamond dresser.
Study on a Magnetic Deburring Method by the Application of the Plane Magnetic Abrasive Machining Process
Authors: Zou Yan Hua , Shinmura Takeo , Wang F.
Published: September 2009

This research studies the influence　of constant pressure acting on the magnetic particles brush for the precision machining of planar and curved workpieces. In particular, it examined the effects of constant pressure on improving the formal accuracy of the workpiece. This process method, constant pressure is applied to the magnetic pole of a conventional magnetic brush, the constant pressure acted to the surface of the workpiece through the magnetic particle brush formed at the magnetic pole surface. The authors conducted a plane magnetic abrasive finishing experiment using both the conventional magnetic abrasive finishing process and the newly proposed constant-pressure magnetic abrasive finishing process to compare the deburring characteristics between the processes for removing burrs from holes drilled in brass plate workpieces. In this experiment, a brass disk with a drilled hole was used as a workpiece. As a result, the difference in finishing characteristics was clarified. The results showed that the burr can be removed by use of this new plane magnetic abrasive finishing process and it is more useful than the conventional magnetic brush for improving the shape accuracy of the workpiece.
Study on Magnetic Field Distribution in the Container of Magnetic Barrel Finishing Machine
Authors: Zhang Y. , Yoshioka Masato , Hira Shin-Ichiro
Published: September 2009

The distribution of magnetic field in the container is important for the polishing ability of a permanent magnet-type magnetic barrel finishing machine. Therefore, in this study, the magnetic field distribution was measured with different magnets arrangement. It is found that the polarity and strength of magnets on a magnet block greatly affect the distribution of magnetic field. Polishing experiments were done to investigate the polishing ability. The relationship between the magnetic field distribution and the polishing ability was discussed. As a result, it was concluded that strong magnetic field led to superior polishing ability.
Diamond Tools for the Grinding of Complex Ceramic Implant Surfaces
Authors: Denkena Berend , van der Meer Marijke
Published: September 2009

Until now, the complex kinematics and geometries as well as high quality requirements have prevented the use of all-ceramic prostheses for the medical treatment of knee joints. High-precision grinding and polishing processes for free-formed ceramic surfaces are essential for this purpose. Constantly changing contact conditions have to be considered to ensure a constant material removal. Within this work, appropriate tools are introduced which are able to adjust to the form variation of the component contour.
Polishing of Nickel Cylinder Using a Photocatalyst and Fluorescent Substance Excited by an Ultraviolet Ray
Authors: Tanaka Takeshi
Published: September 2009

This study targets the development of a polishing technique that uses a photocatalyst and a fluorescent substance excited by an ultraviolet ray. Nickel (hereafter referred to as Ni) was polished chemically and mechanically at the micrometer level under ultraviolet-ray irradiation. Measurements clarified that TiO2 of 0.1-μm grain size, at which size the excitation by the ultraviolet ray was less influential, mechanically polished the Ni. Cathilon (a luminous dye) chemically polishes Ni. The corrosion of the Ni surface became large under ultraviolet-ray excitation. A flat surface was attained on the Ni by chemical and mechanical polishing using both the TiO2 and cathilon, when was irradiated by an ultraviolet ray.
Modeling Material Removal in Fracture Erosion for Brittle Materials by Abrasive Waterjet
Authors: Zhu Hong Tao , Huang Chuan Zhen , Wang Jun , Zhao Guo Qun , Li Quan Lai
Published: September 2009

The abrasive waterjet machining is a powerful tool in processing various materials, especially, for brittle materials, such as ceramic, glass and so on. However, the material removal of a brittle material when impacted by abrasive waterjet is not understood in detail. In this paper, the material removal model in fracture erosion of brittle materials by abrasive waterjet has been developed.
Chip Size Estimation for Effective Blending Ratio of Slurries in Wire Sawing of Silicon Wafers for Solar Cells
Authors: Chen Chao Chang Arthur , Kuo Bing Lin , Liang Jiun Shuo
Published: September 2009

Multi-wire sawing process with slurry has been popularly adopted for wafer slicing of silicon substrates for solar cells. This paper is to investigate the chip size estimation for effective blending ratio of mixing slurry of wire sawing. Different combination of slurry has been studied with microscopic pictures of abrasive grits by SEM and distribution of particle size of slurry. The chip size can be estimated by the developed method and then the TTV of sliced substrates is used to evaluate the blending ratio of slurry for cost efficiency of wire sawing. Experimental results indicate that the slurry with certain ratio of reborn grits increases the TTV value of sliced substrates. As the weight percentage of silicon chips is above 6 % for the blending ratio of 50% reborn abrasive grits after sawing run 2, the slurry is suggested to be changed to new slurry for wire sawing. Under this developed rule, the average TTV can be maintained under 0.016 mm for nominal thickness of 200 m silicon substrates. Results of this paper can be used to estimate the feasible blending ratio for maintaining the TTV under the desired specifications of silicon substrates for cost efficiency.
Abrasive Surfaces Measured by Digital Optical Stereopsis
Authors: de Pellegrin Dennis V. , Torrance Andrew
Published: September 2009

The principle of stereopsis involves measuring an object’s geometry from a pair of images taken at slightly different viewing positions. This technique is frequently used for geographical mapping in satellite-based reconnaissance, however, the same practice has not been reliably applied at the other end of the scale spectrum: i.e. optical microscope imaging. The impediments have been identified and addressed in this work, concluding that optical stereopsis can be applied to microscopical surface examinations, and that the resulting digital elevation models can be of particular use in tribological investigations for performance and failure analysis.
Fabrication of Aspheric Micro Lens Array by Slow Tool Servo
Authors: Chen Chun Chieh , Chao Choung Lii , Hsu Wei Yao , Chen Fong Chi , Chao Chung Woei
Published: September 2009

Owing to the fast development in photonic, telecommunication, and opto-electronic industries, the demand for various micro-lens arrays is rapidly growing. The slow tool servo technique was applied on an ultra-precision diamond turning machine in the present research in conjunction with the tool path generating algorithm for aspheric micro-lens array fabrication. An aspheric lens array of 100% filling factor was successfully produced and the form accuracy and surface roughness were better than 0.15μm and 3nm for all the obtained lenses.
Analysis of Surface Roughness of Low Carbon Steel during Cold Rolling of Thin Strip
Authors: Xie Hai Bo , Jiang Zheng Yi , Du Yan Bing , Wei Dong Bin , Tieu A. Kiet
Published: September 2009

Surface roughness plays an important role in determining the tribological behaviour of mechanical components (e.g. gears and roller bearings etc.) under full-film and mixed (or partial) elastohydrodynamic lubrication conditions. This paper describes a detailed mechanics analysis of the surface roughness transformation of thin strip which has been cold rolled on an experimental mill. Low carbon steel strips were rolled at various speeds and reductions, and the effects of rolling parameters on surface roughness are studied. The results of surface roughness can provide important information to optimise the rolling schedule and to improve the rolled strip quality.
Mechanics of Scratch Marks in Cold Rolling of Thin Strip
Authors: Bai Zhen Hua , Du Xiao Zhong , Jiang Zheng Yi , Tieu A. Kiet , Xu Jun
Published: September 2009

During the cold rolling of thin strip on the 1220mm five-stand tandem cold mills, scratch marks occur on the surfaces of strip and work roll. The surface quality of strip is degraded and the roll wear increases, which resulting in significant economic loss. In this paper, the mechanics of strip scratch marks was studied by carrying out both field experiments and theoretical analysis. Slippage Factor (SF) and Scratch Mark Factor (SMF) were presented to indicate the conditions of strip scratch marks. Meanwhile, mathematical models and simulation code were developed to optimise the rolling schedules and to improve the scratch marks. The practical application of the developed models to the 1220 mm five-stand tandem cold mills verifies the effectiveness of the developed models. The mathematical models can be applied to other similar tandem cold mills.
Rapid Estimation of Rock Cuttability Using Fracture Toughness and Rock Strength
Authors: Tiryaki Bulent , Gipps Ian D. , Li Xing S.
Published: September 2009

Rock cuttability is expressed by specific energy (SE) that is defined as the energy required for cutting unit volume of rock. Direct determination of SE requires a rock cutting rig and is expensive and time-consuming. Therefore, empirical models have been alternative methods for predicting SE from rock properties. Two different predictive models of SE have been developed in this study using regression tree and artificial neural network (ANN) methods. Both empirical models employed the uniaxial compressive strength (UCS) and Mode I fracture toughness (KIC), being derived from tensile strength (t), as predictors. Data from four different studies have been used to develop the models. Statistical analyses on the data set have shown that both UCS and KIC are closely related to SE in a nonlinear form. Numerical and graphical measures of the goodness of the fit and ANOVA test have shown that regression tree and ANN models have performed similarly.
Cutting Edge Preparation for Cemented Carbide Milling Tools
Authors: Denkena Berend , de Leon Luis , Köhler Jens
Published: September 2009

After the grinding process, the cutting edges of cemented carbide milling tools tend to chipping. Chipping has a strong influence on the tool performance. For this reason, the cutting edges are further prepared. Additionally, a cutting edge rounding has an impact on the wear behavior and the process stability. For the cutting edge preparation of milling tools, magnetic finishing is a promising process. This paper describes the process of magnetic finishing. The influencing parameters, i.e. the process time and the distance between the cutting tool and the magnetic disks, are investigated. Furthermore, the effect of magnetic finishing on the tool life is demonstrated using the example of a milling process with titanium.
Dynamics and Stability of Milling Process Considering the Gyroscopic Effects
Authors: Sun Shan Shan , Tang W.X. , Huang H.F. , Xu Xi Qing
Published: September 2009

A dynamics model is established considering gyroscopic effects due to high speed rotating spindle-tool system in ultra-high speed milling (USM). The proposed method for predicting stability enables a new 3D stability lobe diagram to be developed in the presence of gyroscopic effects, to cover all the intermediate stages of spindle speed. The influences of the gyroscopic effects on dynamics and stability in USM are analyzed. It is shown that the gyroscopic effects lower the resonance response frequencies of the spindle-tool system and the stable critical depth of cut in ultra-high speed milling.
Low Cost Wear Monitoring of Bearing Shell in Connecting Rod via I-kaz Method
Authors: Ghazali Mariyam Jameelah , Nuawi Mohd Zaki , Mansor N.I.I.
Published: September 2009

This paper discuss a simple, low-cost method I detecting wear progress of bearing within audio frequency signals; f < 20 kHz. The technique is found to be suitable since it is sensitive to the surface degradation prior to the onset of severe wear. The wear test is conducted under pin-on-disc configuration in a lubricated sliding condition. The results show that the value of I-kaz coefficient Z∞ is represented by scattered data in an I-kaz 3D spaces in which the scattered areas underwent contraction with increased sliding distance. From this statistical analysis, a clear-cut correlation with the established Taylor Tool Life Curve is noted. Here, the lower value of Z∞ indicates severe wear which lies I the failure region of Taylor’s curve. Examination of worn microstructures is carried out using a secondary electron microscopy (SEM). Based on the morphology investigation, it is found that under lubricated test, parallel grooves and craters up to 2 µm in size are present indicating an abrasive wear mechanism has occurred. The surface damages are found to scale with the increasing sliding distance. However the wear resistance behaviour of the bearings seems to improve as the sliding distance is increased.
Study on Path Control Scheme by Laplacian Potential Field and Configuration Space for Vision Guided Micro Manipulation System
Authors: Ojima Hirotaka , Yanai Yoshitaka , Zhou Li Bo , Shimizu Jun
Published: September 2009

. In current bio-engineering, most cell manipulations are manually done by skilled operators. The operations are tedious and time consuming, yet with very low yield rate. The cell manipulation is highly expected to be automated. In this research, we have developed an automated micro-manipulation system, in which a vision control scheme has been proposed and implemented for feedback control of the tool position and tool path. In this paper, a path control scheme using potential approach with configuration space and Laplacian potential field is newly proposed to automatically generate the tool path for moving. The performance of the new control scheme is demonstrated with simulation.
The Research on Endothelialization of the Ti-O Films Surface Modified by Plasma Implantation and Immobilized with Ln and Fn
Authors: Yu Qian , Mei Xin , Chen Jun Ying , Huang Nan
Published: September 2009

In this paper, the Ti-O films were prepared by unbalanced magnetron sputtering deposition system. The films were then treated by plasma immersion ion implantation (PIII) using ammonia gas in order to introduce amino group to Ti-O films surface. The content of amino group on modified Ti-O films can be tested by Acid Orange II. The surface structure, roughness and the chemical composition of elements, were analyzed by x-ray diffraction(XRD),atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). After that, laminin (Ln) and fibronectin (Fn) were covalently immobilized to the surface by the amidogen. The human umbilical vein endothelial cells (HUVEC) were seeded in vitro onto the modified and unmodified Ti-O films surfaces for evaluating the cell compatibility and endothelialization trend. The morphology of endothelial cells (EC) was examined by optical microscopy.The Acid Orange II and XPS results show that the modified Ti-O films treated by plasma immersion ion implantation (PIII) contain amino groups. Endothelial cell culture experiment suggests The Laminin and Fibronectin can further enhance HUVEC adhesion and proliferation. And the PIII treated Ti-O film sample co-immobilized with Ln and Fn possess the best endothelial cell compatibility.
Investigation on Inhibitor Electromigration Anticorrosion Technology for Reinforced Concrete Structure
Authors: Tang Jun Wu , Han Shu Ang , Huang Chang Hong , Li Sen Lin
Published: September 2009

Based on measuring inhibitor effective component N content, chloride removal efficiency and steel polarization resistance, influences of technical parameters of concrete and electric charge amount on the inhibitor electromigration anticorrosion efficiency were described. The results indicated that inhibitor electromigration anticorrosion technology could remove chloride ion, and inhibitor group could move to steel surface so rapidly that corrosive steel could return into passive state, to meet the anticorrosion aim for steel.
System-Level Modeling of Piezoelectric Energy Harvesters
Authors: Tang Li Hua , Yang Yao Wen
Published: September 2009

Accurate modeling and computer aided simulation is advantageous during the design stage of a piezoelectric energy harvesting system. In this paper, system-level finite element modeling (FEM) of a cantilevered piezoelectric energy harvester with a resistor is conducted using ANSYS. Considering that practical energy harvesting circuit includes nonlinear electrical elements, which is beyond the modeling capability of ANSYS, an equivalent circuit modeling (ECM) method is proposed to address the problem. After the parameters of equivalent circuit are identified, system-level simulation is conducted in SPICE software.
Natural Antifouling Materials from Marine Plants Ulva pertusa
Authors: Zheng Ji Yong , Lin Cun Guo , Di Lan Lan , Duan Dong Xia , Ding Hui , Wang Li , Zhang Jin Wei , Peng Yan Lei , Zhou Juan
Published: September 2009

Marine biofouling on the surface of ship hull causes the hydrodynamic drag, fuel increase, and higher costs. In this case antifouling paint is often used to protect the submerged surface from marine organisms. In traditional antifouling paints, toxic biocides have been banned due to their severe environmental pollution. To develop novel environmental benign antifouling agents has been our pursuit, and among them, active substances from marine organism for antifouling application are our research focus. In the paper, a natural material in halobios was isolated from a kind of algae Ulva pertusa, which is the most common green alga. The antifouling activities of their extracts were screened by bioassays with two kinds of fouling organisms, diatom and mussel. The crude extract of ethyl acetate was found to be most active against diatom. Silica gel column chromatography (SGCC) and high performance liquid chromatography (HPLC) were used to further isolate the extract of ethyl acetate. In the SGCC extraction, four elution bands were collected, and minimum inhibitory concentrations (MIC) against diatom were determined. Among the four bands, the lowest MIC is 0.7 mg/mL, related to the band YC-EA. The YC-EA band was separated into four parts, and the second part (EE2) showed an inhibitive effect on the settlement of diatom and mussel. The natural product of EE2 can be characterized by a coupled liquid chromatography-mass spectrometry (LC-MS). Results demonstrated that there are antifouling active substances among extracts of Ulva pertusa. Compounds would be a potentially natural antifouling material, resulting in higher standards of environmental safety with outstanding antifouling performance.
Study on Thixo-Die-Forging of 37vol.%Al/Al2O3 Composite in Pseudo-Semi-Solid State
Authors: Cheng Yuan Sheng
Published: September 2009

A new procedure, thixo-die-forging of ceramics/metal composite in the pseudo-semi-solid state, has been proposed based on powder metallurgy combining with the semi-solid processing of metal. The cup-shaped parts of Al/Al2O3 composite are processed with thixo-die-forging. By metallographic analysis and performance tests, the results show that microstructures are compact, grains are fine and mechanical properties are excellent. The bend strength and fracture toughness of 37vol.%Al/Al2O3 are about 430-690MPa and 8.5-16.8 MPa•m1/2 respectively. Comparing with those of the reaction in situ and high temperature oxidation procedures, the bend strength increases by 50% and 80%, and fracture toughness increases by 29% and 55%, respectively. The results also show that the processing parameters, such as temperature and pressure have great influences on the properties. Thixo-die-forging in the pseudo-semi-solid state can prepare Al/Al2O3 composite with high performance.
Microbially Influenced Corrosion of Copper by Marine Bacterium Vibrio natriegens
Authors: Cheng Sha , Chen Shou Gang , Chang Xue Ting , Liu Tao , Yin Yan Sheng
Published: September 2009

The microbially influenced corrosion of copper by marine bacterium Vibrio natriegens (V. natriegens) was investigated using surface analysis (atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). AFM images corroborated the results from the EIS models which show biofilm attachment over time. The electrochemical results showed that the corrosion of copper was accelerated in the presence of V. natriegens based on the decrease in the resistance of the charge transfer resistance (Rct) obtained from EIS.
New Application of the “Underwater Super-Hydrophobic” Surface in the Corrosion Protection
Authors: Liu Tao , Yin Yan Sheng , Dong Li Hua
Published: September 2009

“Underwater super-hydrophobic” surface applied in the corrosion protection was prepared by melting myristic acid (CH3(CH2)12COOH) adsorbed onto the anodized aluminum. The static contact angle for seawater on the surface was measured to be 154°. The surface structure and composition were then characterized by means of scanning electron microscopy (SEM) with energy dispersive X-ray spectrum (EDX) and atomic force microscope (AFM). The electrochemical measurements showed that the super-hydrophobic surface significantly improved the corrosion resistance of aluminum in sterile seawater.
Identification of Delamination in Anisotropic Laminated Plate
Authors: Du Chao , Ni Qing Qing , Natsuki Toshiaki
Published: September 2009

The energy released from damages may give rise to small surface displacements and cause transient elastic waves in materials. Wave propagation of thin plates usually takes the form of lamb waves, and the modes of the lowest symmetric (S0) and anti-symmetric (A0) lamb waves are called the extensional and the flexural modes, respectively. In this study, a formulation, including the effect of shear deformation and rotary inertia, was derived to valuate the velocity of plate waves. The characteristics of plate wave propagation in thin laminated plates were investigated. Acoustic emission (AE) signals were generated by function generators and lead breaks, and propagated in laminated plates. These waves would be detected by broadband AE sensors because of their high sensitivity. With wavelet transform, AE waves were analyzed and the wave velocities of A0 and S0 modes were exactly calculated. Moreover, a simple method was presented to evaluate delamination in laminated plates. The length of delamination was predicted, and agreed well with the actual length.
Studies on Magnetic Shielding Effectiveness by Finite Element Method
Authors: Wu G.H. , Huang Xiao Li , Duan Mao Qiang , Zhang Qiang , Chen X.
Published: September 2009

Maxwell 2D software is introduced in this paper to calculate the magnetic shielding effectiveness (MSE) properties of iron plate. The three-dimensional magnetic shield is thought isotropic and simplified as two-dimensional model to study its MSE properties by the finite element method. In this method, a uniform magnetic field is generated by two huge magnets and the MSE properties of iron plate, which is in the centre of the uniform magnetic field, is then calculated by the ratio of magnetic field intensity after and before magnetic shielding. All the results indicate that shape of shield materials affects the MSE properties much and the MSE properties of shield with square and circular shape with 3mm in depth are 39.3 and 53.5 dB, respectively. That means the shield shape with fewer bending is favorable to the conductivity of magnetic energy. It also shows that the MSE value decreased linearly with the distance between the magnetic shield and the centre of the magnetic field. That is, the increase of side length of magnetic shield will lead to the decrease of MSE properties of iron plate, which is agreement with the theoretical prediction of Lu H.M. model. Furthermore, the MSE properties of double layers shielding (iron plate with 2mm in depth and 3mm iron plate with 81% porosity) are also studied in this paper. The effect of places of iron plate with 2mm in depth is presented to play important role in double layers shielding and the MSE value increases with the distance between the two magnetic shields. Compared to that of shield with circular shape, the MSE properties are similar to each other when the distance of the two shields is 8mm. In addition, it also indicates that the MSE value is higher when the iron plate with 2mm in depth is inside of the other than that when it is outside.
First-Principles Study on the Conductive Properties of P-Doped ZnO
Authors: Guan Li , Li Qiang , Li Xu , Guo Jian Xin , Geng Bo , Jin Li Tao , Zhao Qing Xun , Zhao Jing Wei , Liu Bao Ting
Published: September 2009

In the present paper, the lattice structure, band structure and density of state of pure and P-doped ZnO are calculated by first-principle method based on density functional theory. By analyzing the Mulliken charge overlap population and bond length, it is found that the bond of P-Zn is longer and stronger than O-Zn bond for PO-ZnO. But for PZn-ZnO, the O-P bond becomes shorter and more powerful than O-Zn bond. Also, weak O-O bonds are formed in this case. Our results show that the final total energy of PO-ZnO is lower than PZn-ZnO. The lattice structure of PO-ZnO is more stability than PZn-ZnO. For PO-ZnO, The Fermi level moves into the valence band, which expresses that the holes appear on the top of valence band and thus the PO-ZnO exhibits p-type conductivity. For PZn-ZnO, the Fermi level moves up to the conductor band and the total density of states shifts to the lower energy region, thus PZn-ZnO shows the n-type conductivity.
Atomic and Electronic Structure of LaAlO3 and LaAlO3:Mg from First-Principles Calculations
Authors: Guan Li , Jin Li Tao , Zhang Wei , Li Qiang , Guo Jian Xin , Geng Bo , Zhao Qing Xun , Liu Bao Ting
Published: September 2009

In the present paper, the lattice structure, band structure and density of state of LaAlO3 and LaAlO3:Mg are calculated by first-principle method based on density functional theory. Firstly, we select the different cutoff energy and k-point grid in the calculations, and obtain the most stable geometry structure of single crystal LaAlO3. The calculated lattice parameters are a=b=5.441 Å, c=13.266 Å, which matches with experimental values. To deeply understand the electronic structure of LaAlO3, a 2×1×1 super-cell structure is established and the doping concentration of Mg at Al sites is 25%. From the band structure and density of states, it can be seen that LaAlO3 has a direct band gap Eg=3.6 eV. However, LaAlO3:Mg has a larger band gap Eg=3.89 eV and the Fermi level enters into the valence band, which indicates the holes are introduced. The calculated results show that the conductivity of LaAlO3:Mg is better than pure LaAlO3, which is in good agreement with experimental results.
Kinetics of Sol-Gel Transformation for the Preparation of TiO2 Ultrafiltration Membrane
Authors: Cao Xue Ping , Huang Wei , Jing Wen Heng , Xing Wei Hong
Published: September 2009

The sol-gel technique is considered to be one of the most practical methods for producing ceramic membranes, and the properties of the sols could affect the microstructures of the desired products. Especially, optimized viscosity and a short gelation time can reduce the sol particles infiltrate into the pores of the support. So how to control the forming process of the gel is essential for fabricating the membranes. In this paper, we developed a kinetic equation of sol-gel transformation to study the relationships between viscosity and time of titanium sol systems by using N, N—Dimethylformamide (DMF) as solvent. Both the growth process of the sol particles and activation energy of the process were investigated according to the kinetic curves. The results indicate that the viscosity of sols decreases with the increment of R and temperature, but increases with rw, at the same time the gelation time decreases with rw, temperature and R. Furthermore, the growth of sol particles versus time accord with the NLG model, and the activation energy of gelation process decreased with R. When R changed from 2 to 6, the activation energy was decrease from 12.48KJ/mol to 9.35KJ/mol. According to the analysis of the results of the sol-gel transformation, a shorter gelation time could be obtained by increaseing the rw, R and the gelation’ temperature.
Low-Velocity Impact Characteristics of Carbon Fiber Composites Lattice Core Sandwich Structures
Authors: Wang Shi Xun , Wu Lin Zhi , Ma Li
Published: September 2009

Since composite sandwich structures are susceptible to low-velocity impact damage, a thorough characterization of the loading and damage process during impact is important. In the present paper, the low-velocity impact response of carbon fiber composites lattice structures are investigated by experimental and numerical methods. Impact tests on composite plates are performed using an instrumented drop-weight machine (Instron 9250HV) and a new damage mode is observed. A three-dimensional finite element model is built by ABAQUS/Explicit and user subroutine (VUMAT) to predict the peak loading and simulate the complicated damage problem. It can be found that numerical predictions coincide well with experimental results.
Effects of Materials on Formation of Double-Layered Liners Shaped Charges
Authors: Zheng Yu , Wang Xiao Ming , Li Wen Bin , Yao Wen Jin
Published: September 2009

In order to study the effects of liner materials on the formation of Shaped Charges with Double Layer Liners (SCDLL) into tandem Explosively Formed Projectile (EFP), the formation mechanism of DLSCL was studied. Utilizing two-dimensional finite element dynamic code AUTODYN, the numerical simulations on the mechanical phenomenon of SCDLL forming into tandem EFP were carried out. X-ray pictures were obtained after Experiments on SCDLL. Comparisons between experimental results and numerical simulation results have good agreement. It can be concluded from the results that the materials properties and configurations of both liners are crucial to the formation of tandem EFP.
Numerical Simulation on Characteristics of Dense-Phase Pneumatic Conveying in Horizontal Pipe
Authors: Liu Zong Ming , Yi Hua , Zhao Wei Lin , Li Xian Song
Published: September 2009

Numerical simulation of dense-phase pneumatic conveying flow field was carried out by using k-ε-ks-εs two-fluid model in horizontal pipe on the basis of kinetic theory of granular flow. The coupling issue between gas phase and solid phase was taken into account in the process of simulation. Such characteristics of flow field along pipe as pressure distribution, concentration distribution, gas and particle velocity distribution were obtained. The results of numerical simulation showed the tends of pressure, gas velocity, particle concentration in pipeline. The results of numerical simulation were compared with experimental results, and it showed that the simulation results were validated by the experimental data, which indicate that the model and the corresponding algorithm have higher accuracy and better prediction. Thus the numerical simulation method can reveal the basic characteristics of dense phase pneumatic conveying in horizontal pipe.