bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical Properties of PDMS Membrane and Influences of Commonly Used Chemicals in Microfabrication
Authors: Liu Miao , Sun Jianren , Sun Ying , Chen Quanfang
Published: June 2009

Microfluidics is both a science and a technology that offers great and perhaps even revolutionary capabilities to impact the society in the future. Polydimethylsiloxane (PDMS) has been widely used in fabricating microfluidic systems but few attentions were paid in the past to mechanical properties of PDMS. Very importantly there is no report on influences of microfabrication processes which normally involve chemical reaction processes. A comprehensive investigation was made by authors to study fundamental issues regarding chemical emersion and their effects on mechanical properties of PDMS. Results shown in this work can be used to guide future developments of microfluidics in utilizing PDMS especially those devices involve actuation of PDMS membranes.
Trends in Funding, Markets and Entrepreneurship: Effect on Micro and Nano Technologies
Authors: Kassicieh Sul , Dai Na
Published: June 2009

As regions compete, they have made significant changes to the way they attract new business including activities that increase funding opportunities, enhance market penetration and sustainability and encourage more entrepreneurial activities. This has implications for Nano- and Micro-technologies and seems to encourage the integration of market forces with technological capabilities.
Cutting Force Analysis to Determine the Performance of Micro End Milling Process of Silicon Wafer
Authors: Rusnaldy  , Ko Tae Jo , Kim Hee Sool
Published: June 2009

There is a lack of fundamental understanding of micro-end-milling of silicon wafer, specifically basic understanding of material removal mechanism, cutting forces and machined surface integrity in micro scale machining of silicon. It is necessary to determine the forces generated during the cutting operation due to chip thickness along with tool geometry, tool material properties and workpiece properties because cutting forces will provide vital information for the design, modeling and control of the machining process. In this study, cutting force data can be used to determine cutting regime machining of silicon wafer.
Research for Metallographic Organization of Gold Nanoparticles
Authors: Han Min , Yang Zhilin , Yang Ruomian
Published: June 2009

We used the solution of HAuCl4 and Na3 C6 H5 O7 to prepare the gold nanoparticles. The different shape and sizes of gold nanoparticles depends on the different amount of solution. We used gold nanoparticles with 35nm diameter to do experiments. Put the colloidal gold on a aluminum plate, copper plate and plastics plate, after dried, several items of tests had been done. we could see the mechanical property of gold nanoparticles such as hardness, extend rate was changed a lot than the common gold material. The reason was that the metallographic organization of gold nano materials was much tiny than common gold materia.
Analysis and Design of a Three-Limb Six Degree-of-Freedom Parallel Micromanipulator With Flexure Hinges
Authors: Wang Lefeng , Rong Weibin , Sun Lining , Jiao Jie
Published: June 2009

A novel three-limb six degree-of-freedom (DOF) parallel micromanipulator with flexure hinges driven by piezoelectric actuators is presented. Its uniqueness lies in three inextensible limbs with specified flexure hinges and driving its input motions from a monolithic base plate that consists of three 2-DOF compliant mechanisms, unlike of the most six-limb parallel manipulators. The manipulator is very compact and its structure is simple. The kinematic problem of the manipulator is solved by using the kinematic influence coefficient theory. As a result, the velocities of the movable platform, the limbs and the flexure hinges are derived. The stiffness model of the micromanipulator is determined considering the elastic deformations of the flexure hinges according to the virtue work principle. The design targets and the primary design principles of the flexure hinges are discussed and the precision position controller modules are used to control the micromanipulator. At last the basic experiment results are presented.
Rapid Measuring Method of Micro-Motion Based on Time-Averaged Microscopic Interferometry
Authors: Guo Tong , Hu Chunguang , Chen Jinping , Fu Xing , Hu Xiaotang
Published: June 2009

An optical measurement system and method for out-of-plane motion testing of micro-structures is presented. Based on a Mirau type microscopic interferometer, the system adopts time-averaged interferometry to realize the measurement of the out-of-plane dynamic properties of movable micro-structures. For mapping the zero-order Bessel function modulating the contrast of two-beam interference fringes, a four-step phase-shift technique is applied. An experiment on a micro-resonator demonstrates that out-of-plane motion can be measured at any frequency with a lateral resolution in the micrometer range and a detection limit around 5nm.
Forced Response of Electromechanical Integrated Electrostatic Harmonic Drive to Voltage Excitation
Authors: Xu Lizhong , Zhu Cuirong , Qin Lei , Zao Yanling
Published: June 2009

In this paper, a micro electromechanical integrated electrostatic harmonic drive system is presented. The operating principle of the MEMS is introduced. The exciting electric field force under exciting voltage is given. Based on the electromechanical coupled dynamic equations of the drive system, by generalized force and generalized coordinate, the forced response of the drive system to voltage excitation are obtained. The forced frequency responses of the drive system to voltage excitation are investigated. Changes of the frequency response along with the system parameters are given as well.
The Study of Photocatalytic Degradation of Formaldehyde Under the Action of Mass Transfer
Authors: Lu Yuanwei , Ma Chongfang , Li Wencai , Sheng Jianping , Wang Wei
Published: June 2009

Photocatalysis is an emerging and promising technology for indoor air purification, which has the higher reaction rate at the higher pollutant concentration and vice versa, and the toxic intermediate products were produced meantime. However, the concentration of indoor pollutant is usually very low. So how to improve the photocatalytic reaction rates in indoor contaminant levels in building and to eliminate the intermediate toxic products are the keys of commercialization of this technology. This paper immobilized the TiO2 on the active carbon and analyzed the effect of mass transfer due to the absorption of AC on the photocatalytic reaction rate. The experimental results shown that the photocatalytic reaction rate was improved for the local concentration of contaminants on the surface photocatalyst TiO2 was enhanced by adsorbent activated carbon. With the increase of air stream velocity, the photocatalytic reaction switched from mass transfer control process to photocatalytic reaction control process. The switch point was advanced for the absorption of AC comparing with TiO2 immobilized on the surface of glass. The indoor formaldehyde with low level concentration can be decomposed to the range of indoor air quality standards by the TiO2/AC filter.
Overview of Micro-Manufactured-Based Micro Direct Methanol Fuel Cell Development for Portable Applications
Authors: Guo Jiusheng
Published: June 2009

With increasing demand for portable electronics devices, on-board chips, sensors, actuators in microelectronics, medical, and wireless telecommunication industries, etc., a small-power (milliwatt or subwatt range) alternative power source to lithium ion battery is required. Micro-scale fuel cell, especially micro Direct methanol fuel cell (μDMFC) has attracted attention as a small-size and portable power source, due to the fuel’s capability to deliver high power density per volume and weight. The miniaturization of μDMFC requires special manufacturing techniques different from conventional machining methods in macro-DMFC, which can fabricate the key components in μDMFC and assembly them together in micro-scale level. Thanks to integrated circuit fabrication and Micro-electro-mechanical –system (MEMS), current approach to developing μDMFC is adoption of Silicon micromachining technologies to creating micro-fluidic channels (for fuel and gas delivery). The deposition of thin films of exotic materials using semiconductor techniques is applied to make electrodes and current collector. In the paper, an overview of design and microfabrication of μDMFC was performed. The design configuration of the μDMFCs have been summarized and evaluated. The outputs of the designed and microfabricated μDMFC were analyzed and compared. Finally, the requirements for designing and micro-manufacturing the components and system in μDMFC, and packaging are proposed from technical and cost point of view.
Sensing Flow Separation on a Typical Aerofoil by MEMS Flexible Thermal Sensor Array
Authors: Liu Kui , Yuan Wei-Zheng , Deng Jin-Jun , Ma Bing-He , Jiang Cheng-Yu
Published: June 2009

When a fluid flows over a solid surface, viscous effects generate shear stress, or skin friction, on the surface. Knowledge of such wall shear stress is essential for understanding the dynamics of fluid flow, and its measurement holds great importance for investigating and controlling wall-bound turbulence and flow separation in aerodynamic control. MEMS play an important role for studying gaseous or liquid fluid flows experimentally due to device dimensions on the μm-scale. For aerodynamic applications, the realization of sensor-actuator networks on airfoils is a challenging task to improve the lift properties of aircrafts by the precise detection and the systematic manipulation of the transition point from laminar to turbulent airflow conditions. Based on the well-established principle of thermal anemometry, an array of thermal sensors on a flexible polyimide substrate was developed. The first application of this technology has produced a flexible shear-stress sensor array. Apparently, this technology can be applied to produce a flexible skin with other sensing elements, such as temperature or pressure sensors. In addition, two signal processing methods of the sensor array signals have been proposed to detect the location of the flow separation point on curved surface for the positive flow control purpose. The computation parameter is based on thermal method measurement the surface local shear stress. The flexible sensor array has also been used to detect instantaneous separation region on the surface of a NACA0012 typical aerofoil. In a first step, CFD (Computational Fluid Dynamics) simulations were performed to estimate the corresponding shear stress distribution within the NACA0012 typical aerofoil at flow conditions is the velocity 40m/s and AOA 16° To illustration the method, the low speed wind tunnel testing data was used to analysis the accuracy and effectively of the method presented in this paper, which can demonstration that the method provides an applicable, efficient tool for the flow separation analysis in the it’s location decision aspect.
Hardness Determination of Au Thin Film by Nanoindentation Technique: A Comparative Study on Various Characterizing Methods
Authors: Zhou Xiangyang , Jiang Zhuangde , Wang Hairong
Published: June 2009

The purpose of this paper is to find a reliable method for determining the hardnesses of soft metallic thin films on hard substrates. Based on the nanoindention experimental data for a 504 nm Au thin film deposited on glass substrate system, several possible methods are applied and the results come from them are compared. The results reveal that the Oliver-Pharr method is strongly influenced by the material pile-up behavior and substrate effect that leads to an erroneously overestimated hardness. However, the methods based on traditional area calculations by SEM image, work of indentation principles during the indentation cycle and constant modulus assumption calculations all can effectively avoid the effect of pile-up and minimize that of substrate. Among three, the results from indentation method are obviously much higher than those from other two. Hence we argue that the results by SEM image method and constant modulus assumption calculations are more reasonable.
Thermal Transport Properties of Multi-Walled Carbon Nanotube Arrays
Authors: Xie Huaqing , Cai An , Wang Xinwei
Published: June 2009

A laser flash technique was applied to measure the thermal diffusivity along a multi-walled carbon nanotube (CNT) array in temperature range of −55∼200 °C. In the measurements, a nanosecond pulsed laser was used to realize noncontact heating and the temperature variations were recorded by an infrared detector. The experimental results show that the thermal diffusivity of the CNT array increases slightly with temperature in the −55∼70 °C temperature range and exhibits no obvious change in the −75∼200 °C temperature range. The CNT array has much larger thermal diffusivity than several known excellent thermal conductors, reaching about 4.6 cm2s−1 at room temperature. The mean thermal conductivity (λ) of individual CNTs was further estimated from the thermal diffusivity, specific heat (Cp), and density (ρ) by using the correlation of λ = αρCp. The thermal conductivity of individual CNTs increases smoothly with the temperature increase, reaching about 750 Wm−1K−1 at room temperature.
Development of a Novel Micro-Gripper Integrating Tri-Axial Force Sensor
Authors: Wang Jiachou , Rong Weibin , Sun Lining , Xie Hui , Chen Wei
Published: June 2009

A novel micro gripper integrating tri-axial force sensor and two grades displacement amplifier is presented in this paper, which bases on the technology of Piezoresistive detection and use PZT as its micro driving component. The micro tri-axial force sensor is fabricated on a single-crystalline-silicon by the technology of MEMS and consists of a flexible cross-structure realized by deep reactive ion etching (DRIE). The arms of the cross-structure are connected to a silicon frame and to the central part of the cross-structure. After modeling the amplifier structure of micro gripper and the sensor, finite element method (FEM) is used to analyze the displacement of the micro gripper and the deformation of the cross-structure elastic cantilever. A calibration method of tri-axial sensor based on the technology of microscopic vision and the principle of bending deflection cantilever is proposed. The experimental verified that the sensor are high level of intrinsic decoupling of the signals from strain gauge, high resolutions in all three axes, high linearity and repeatability and simple produce of calculation. And also show the micro gripper is reasonable and practical. The sensor is capable of resolving forces up to 10mN with resolution of 2.4μN in x axis and y axis and up to 10mN with resolution of 4.2μN in z axis; the gripping displacement of the micro gripper is from 20μm to 300μm.
Design a System of Ar-Ion Laser Enhanced Anisotropic Etching
Authors: Wen Dianzhong
Published: June 2009

This paper a System of argon-ion laser enhanced anisotropic etching is designed. A basic description of the structure and principle of the system will first be presented. This system can be described as enhanced etching rate of silicon. It also has the important advantage of not requiring the silicon is covered with a thick of oxide or other masked for any plane of silicon crystal that adds considerable complexity to the manufacture. When experiment temperature is 90 °C and KOH density is 34mol, an averaged instantaneous etching rate as high 25μm/min has been observed in silicon for a 4.6W input laser power, this etching rate register a 500% increase model on conventional anisotropic etching of silicon. Discussing the anisotropic etching rate of silicon dependence on the laser power and on the temperature are further. The experiment results show that the system structure design is reasonable and it can meet the requirement of every planes of silicon crystal etching, it can be used widely in variety of application aspects.
Optical Property Analysis of Microbolometer Based on MEMS
Authors: Li Shibin , Wu Zhiming , Liao Naiman , Jiang Yadong , Li Wei , Yu Junsheng
Published: June 2009

The optical constant of TiN and amorphous silicon thin film as well as film thickness of thermal resistive amorphous silicon were measured by ellipsometry apparatus, which were in agreement with the result from SEM section analysis. According to optical admittance matrix theory, relation between sensing film thickness, resonant cavity height of microbolometer and infrared absorptivity was simulated using FEA (Finite Element Analysis) MatLab software. Optimal film thickness and resonant cavity height for high infrared absorptivity ranging from 3–5 to 8–14 μm atmosphere window infrared bands were achieved, which provides reliable evidence to improve the sensitivity of microbolometer.
Vibration Control System for a Sub-Micro Ultra-Precision Turning Machine
Authors: Gai Yuxian , Liu Huiying , Dong Shen
Published: June 2009

For a sub-micro ultra-precision turning machine using airsprings as vibration isolation elements, a 5 FOG mathematical model is established, activation f acted on the machine bed is as the input, the output are vertical displacement y1, oscillating φ1, ψ1 around the horizontal axle x and z of the machine bed, vertical displacement y2 of the main spindle box, and vertical displacement y3 of the slider. The equations for vibration system of 5 FOG are solved. The results indicate, when actuation force f ≠ 0, the outputs of all 5 FOG are increasing with the increasing of f. when activation f = 0, the outputs of all 5 FOG tend to zero. Assuming f include the vibration of machine base and an external force, when external force is equal to that of the vibration of machine base, then f = 0. The vibration of 5 FOG can be effectively isolated, so electromagnetic actuators as an external force, also as active vibration isolation elements can be used in the isolation system. Three electro-magnetic actuators arranging as triangle act as an external force, the quantity is equal to that of the base vibration, and the phase reverse. In fact ultra-precision turning machine is a complicated mechanism system and in the machining process, the headstock and horizontal-slider are in the movement, that is to say, the center of mass of the ultra-precision machine is changeable. Impossible is f = 0 for a practical control. In order to get a effective vibration isolation, fuzzy controller is used. The synthetic experiments have been done for the 5 FOG vibration system of the ultra-precision turning machine. The result of three actuations experiment that has been done in y direction indicates that the vibration of y direction, and oscillating φ1, ψ2 around the horizontal axle x and z of the machine bed are to be controlled. A work-piece of aluminum alloy has been machined using the sub-micro ultra-precision turning machine with the active vibration isolation elements, and without the active vibration isolation elements, AFM microscope graphs show the surface roughness of the work-piece machined by the former better as by the latter.
A Micro Electrical Machining CNC System Based on RTAI
Authors: Guo Rui , Zhao Wansheng , Li Gang
Published: June 2009

Micro Electrical Machining (μ-EM) has been regarded as a key technology for micro-machining because of the high precision and good surface quality that it can achieve. This paper presents the development of a Computer Numerical Control (CNC) system dedicated for μ-EM. RTAI which is a hard real-time operating system based on Linux is applied to meet the requirements of the μ-EM CNC. RTAI offers high performance compared with commercial real-time operating systems. To deal with the difficulties in micro electrodes online fabrication and compensation, an on-line measurement subsystem which has a resolution of 1.61 μm and an overall magnification ranges from 113 to 729 is integrated into the CNC system. The contour of micro electrodes can be extracted by means of the Canny edge detection algorithm. The micro electrodes’ dimension can be measured on-line manually or automatically. Machining verifications demonstrate that a μ-EM machine equipped with the RTAI based CNC system has a good potential of manufacturing not only micro-holes and micro-shafts but also complex 3D micro structures and parts.
The Mechanism and Process of Anodic Bonding for Glass and Aluminium
Authors: Meng Qingsen , Liu Cuirong , Hu Lifang , Li Yude
Published: June 2009

The work mainly investigates the bonding mechanism of the anodic bonding between glass and aluminium film, and bonding of multi-layers glass-Al stack is achieved by the common anode process. The SEM and EDS are applied to investigate the interfacial structure of Al-glass. The bonding area consists of glass, transitional layer and aluminium. The transitional layer is composed of Al2O3 and SiO2. The microstructure and distribution of the elements are almost the same in both sides of the Al interfaces. From the SEM micrographs a conclusion can be deduced that there is no difference between the bonding interface of the Al-glass and the glass-Al-glass. It is shown that the voltage and temperature are the main factors to influence the current, and the current would change a lot if the voltage or temperature is varied. According to the experimental results, if the voltage and temperature are given, the peak current of the glass-Al-glass bonding is two times larger than the Al-glass bonding. The pulling test machine (INSTRON-5544) is applied to take a tensile test for evaluation of bonding strength of the samples. And it is found that the broken occurs inside the glass not in the bonding interface. The fractures of the simples is analyzed by SEM, and the fractures morphology of the cleavage are similar to the surface of a shell, it indicates that the glass-Al-glass wafers can be bonded very well due to the applying of a common anode. And the bonding can be achieved at 350°C–450°C by applying a voltage of 400V-800V. Using the technique, five layers of glasses to aluminium films are also bonded together.
Enhancement of Single-Phase Refrigerant Mixture (R-407C) Flow in Meso-Scale Heat Exchangers Using Micro-Coils
Authors: Shariff Yasir M. , Ravigururajan T. S.
Published: June 2009

Experimental results from single-phase refrigerant mixture flow in smooth and micro-coil enhanced meso-channels are presented. R-407C — a mixture of R-32 (23%)/R-125 (25%)/R-134a (52%) — is used as the working fluid and different micro-coils are used in conjunction with two meso-channels (2.78mm and 3.97 mm) to obtain distinct roughness parameters. The flow was varied over a range of Reynolds numbers and experiments were conducted over a heat flux range of 2 to 11 kW/m2. The heat transfer coefficient was found to be dependent on both the heat flux as well as mass flux levels. Results show that heat transfer characteristics are comparable to R-113, and that micro-coil inserts enhanced the heat transfer performance compared to the performance in smooth meso-channels.
Structure Design, Dynamic Analysis and Test of FPSM of APT System in Free Space Laser Communication
Authors: Sun Li-Ning , Shao Bing , Qu Dong-Sheng
Published: June 2009

As one of the best solutions for future space communication, free space optical communication possesses such advantages as high data rate, large capacity and high secrecy as compared with microwave communication. However, the extremely narrow beam width calls for severe acquisition, pointing and tracking requirements. As a key component of laser beam Acquisition, Pointing, and Tracking (APT) system for free space optical communication, the compact Fine Pointing Steering Mirror (FPSM) determines the performances of the communication system. This paper presents a new type structural design of FPSM — a piezoelectrically-driven micro-positioning deflective mechanism where the tilt movements are implemented by the elastic deformation of flexible rings. It provides fast and precise control in tilt movements around X-axis and Y-axis. The mechanism is machined from one solid alloy steel block cut by wire-EDM (electric discharge machining). The flexure rings promise zero friction, zero clearance and excellent guiding accuracy. The mirror, 36mm in diameter, is driven by four piezoelectric actuators (two pairs) spaced at 90° intervals. Each actuator pair works as a unit in push/pull mode. The differential design exhibits excellent angular stability over a wide temperature range. The stiffness model of the flexible ring was setup through the analysis of structural mechanics. The FSPM has been simplified to springs-particle system. A dynamic model was then presented based on Lagrange Equation, and modal analysis and experiments were then performed. Dynamic calculation demonstrates that the first order, the second order and the natural frequency of the FSPM is 1.278 KHz, 1.653 KHz and 1.653 KHz. Modal analysis shows that the first, second and third order natural frequency is 1.308 KHz, 1.525 KHz and 1.530 KHz. The experimental test displays that the first, second and third order natural frequency of the FPSM is 1.28 KHz, 1.56 KHz and 1.58 KHz. The error between three of methods is less than 10%. It demonstrates that the novel FSPM has excellent performance and can meet the dynamic requirements for establishing optical communication link.
Current Control Amplifier for Piezoelectric Actuator in Precision Positioning Control
Authors: Ru Changhai
Published: June 2009

Piezoelectric transducers are known to exhibit less hysterisis when driven with current or charge rather than voltage. Despite this advantage, such methods have found little practical application due to the poor low frequency response of present current and charge driver designs. In this paper, a current control piezoelectric amplifier is presented which can reduce hysteresis. Special circuits and a hybrid control algorithm realize the quick and precise positioning. Experimental results demonstrate that the amplifier can be used for dynamic and static applications. Low frequency bandwidths can be achieved.
Research on Machining System Design and Machining Method of Micro Optical Aspheric Surface
Authors: Huang Hao , Guo Yinbiao
Published: June 2009

At present high precision aspheric surface has been widely used in high performance optical system, but at current technical condition, the machining of high precision aspheric surface is still difficult. According to the requirement of high precision micro aspheric surface machining, three machining method of spherical wheel machining in micro axisymmetric aspheric has been put forward. And a high precision manufacturing and measurement system based on the machining method mentioned above has been designed and realized. It adopts the technology of tool uniform wear and error compensation, can be chose different machining method, and reach to the requirement of high precision micro aspheric surface machining.
Study the Order of Morphology Self-Assembled Triblock Copolymer Thin Films by FFT of the AFM Images
Authors: Cao Yongzhi , Dong Shen , Liang Yingchun , Sun Tao , Zhao Xuesen
Published: June 2009

A variety of block copolymer thin films with well-ordered nanostructures, which can be employed as templates for nanotechnologies including nanostructure membranes, nanoparticle synthesis, photonic crystal, and high-density information storage media, can be realized simply and at low cost by self-assembly. Long range ordering of morphology is paramount to realize applications of self-assembled block copolymer thin films in nanotechnologies. A better understanding of what parameters affect the ordering process can lead to the production of highly ordered arrays of nanostructures. In this paper, in order to effectively analyze the improvement in ordering, the Fast Fourier transform (FFT) analysis of the AFM images is used. Fast Fourier transform provide a mathematical analysis of the image that is similar to producing a diffraction pattern. From this “diffraction pattern” information on the order in the system can be obtained. Moreover, calculating an ordering parameter from the FFT provides a quantitative measure of the order present in the polymer template. The order parameter is calculated using equations which were tested against a manufactured perfect system and imperfect system to ensure that a perfect system would provide an order parameter of 1 and an imperfect system would create an order parameter of 0. The results show that the method is reasonable and effective to analyze the improvement in ordering that is achieved by using solvent annealing. Furthermore, the method can be used to understand the parameters in triblock copolymer thin film self-assembly process that create the most well ordered system.
Study on Preparating Technology of Nano Ni-TiN Composite Layer by Ultrasonic-Electrodepositing Method
Authors: Wu Meng-Hua , Xia Fa-Feng , Li Zhi
Published: June 2009

The ultrasonic-electrodepositing method is used for preparing nanocermet Ni-TiN composite layers on steel substrates in this paper. The action of mechanical disturbance of ultrasonic wave on the mass-transfer of electrolyte, the restraint action of ultrasonic cavitation effect on reunion of nano particles and the action of electric pulse parameters on the nucleation and growth of grains have been studied by experiments. The nanocermet Ni-TiN composite layer consist of nanocrystalline nickel (30–60nm) and nano TiN particles has been obtained on the surface of common metal substrates by using optimum technology parameters. The composite layers possess following characteristics: firmly combining with substrates and combining force was 89N, thickness was between 11–12 μm, and average surface hardness was HV606.
Research and Fabrication on Eddy Current Sensor Based on UV-LIGA
Authors: Zheng Xiao-Hu
Published: June 2009

An analytical model of an eddy current sensor designed for noncontact distance measurement was presented. The device consists of two planar coil (driver coil and pickup coil) stacked on the magnetic core. The planar coil fabricated by UV-LIGA technology with SU8 photoresist was illustrated, and the permalloy magnetic core electroforming process was presented also. Tested with 10–50KHz sine signal, the output voltage on the sensing coil rearched 30mv with an stainless target placed at a distance of 10μm, and the experimental showed a linear relation between the distance and output voltage within 50μm distance. The whole size of the device was: Φ5mm × 1.5 mm. The results demonstrated that the device could nondestructive evaluate the distance and be easily integrated on chip.
Lensless Optical System for Fabricating Holographic Photonic Crystal
Authors: Chen Wei , Liu Shou , Zhang Xiangsu , Liu Ying , Ren Xuechang
Published: June 2009

A compact lensless optical system is proposed in the paper, in order to generate the mask with 2-dimensional hexagonal lattice used for photonic crystal fabrication. The key element in the system is a holographic optical element consisting of three symmetrically arranged holograms. Under the illumination of a spherical wave, the element can generate three plane waves to form uniform hexagonal lattice pattern with large size. The technique is suitable for industrial applications to achieve fast and mass production of photonic crystals in semiconductor materials.
The Experimental Study on Ignition Mechanism and Combustion Characteristics of Micro Gas Engine
Authors: Ren Taian , Lu Dejiang , Jiang Zhuangde , Zhu Mingzhi
Published: June 2009

In this article, the experimental studies on ignition mechanisms and combustion characteristics of the micro combustor have been made for the designs and ignition of the combustor. A set of special experimental devices of ignition are designed and fabricated based on Si-based MEMS technology. The combustors of the experimental devices are the square cavity that varied from 1mm to 9mm in length and from 0.5mm to 4mm in height. The spark electrodes are Au electrodes. The gaps of electrodes are 10μm, 40μm, and 100μm. The experiments of the ignition mechanisms of premixed H2/air, the concentration limit of ignition, residence time, ignitor-breakdown voltage, and heat transfer have been made on the devices. The ignition mechanisms and combustion characteristics of H2/air in micro combustor have been discussed based on the results of experiments. The experimental results indicate that the ignition of the premixed H2/air in micro combustor is feasible. The range of the ignitable concentration has a significant reduction. The combustion is subject to the back-fire and liable to suffer from flame extinction. The height is at least larger than 0.61mm. The ignitor-breakdown voltage is at least 350V when the gap of ignition electrodes is 10μm.
A Microchannel Heat Sink With Unitary Circular Flow and Short Distance Heat Transfer Mode: Design and Analysis
Authors: Wang Y. , Ding G. F.
Published: June 2009

The simulation of the forced convection heat transfer occurring in a microchannel heat sink with unitary circular flow and short distance heat transfer is presented. The temperature and velocity distributions of the coolant in the microchannels under the different flow rates were performed using the commercial FE software package [ANSYS]. The lowest flow rate satisfying the maximum operating temperature of the electronic device is 2ml/min with the input heat flux 25W/cm2. The temperature difference along flow direction in the lognitudinal channel with the transverse channel arrays is reduced compared with the traditional parallel channel structure. A uniform temperature distribution and high heat transfer efficiency are developed.
Modeling of an Electrostatic Micromotor Based on a Levitated Rotor
Authors: Chen Xi , Han Fengtian , Liu Yunfeng
Published: June 2009

This paper presents a mathematical model developed for an electrostatically levitated micromotor in which the ring-shaped rotor is levitated by electrostatic force in five degrees of freedom (DOFs). A glass/silicon/glass sandwich structure is utilized in this electrostatic micromotor, which is based on the technology of micro-electro-mechanical systems (MEMS). In the center of ring-shaped cavity formed by ICP between the top and bottom glass plates, the rotor is levitated by the five DOFs position servo system and driven by speed control system. In this paper, the mathematical model for the motion control of the rotor in five DOFs is developed. This model describes the capacitances and electrostatic forces between the rotor and associated electrodes, and moments of two rotations about the x, y-axis. The rotational torque model governing the rotor’s rotational speed is also described. In order to obtain the analytical nonlinear models for error analysis, these integral equations are expanded using the Taylor’s series. Moreover the finite element model and its simulation results are obtained by using ANSYS. In terms of comparison between the simulated results and the nonlinear models, the modeling accuracy of the micromotor can be evaluated. Furthermore, the error characteristics of the linearized models via rotor displacement are analyzed. Thus, position sensing and control of both the rotor’s motion, and the rotational speed, can be achieved based on these linearized models of electrostatically levitated micromotors.
Numerical Simulation of Gaseous Flow Characterstics in Microchannels
Authors: Zhang Tiantian , Jia Li
Published: June 2009

Flow characteristics of nitrogen flows in the three different microchannels (hydraulic diameter Dh ranging 30–3000 μm) have been investigated numerically considering of the effect of compressibility and viscosity heating. It indicated that pressure drop at inlet and outlet is nonlinear with Reynolds number. Transition Re is as low as about 1200 for microchannels with Dh = 300 μm. To incompressible flow, Dh, has no effect on friction factor f. However, L/Dh has great effect on f, and f increases with the decrease of L/Dh. It was found from numerical results that fRe can be expressed as a function of Mach number. By compared with the experimental results, the function has been proved right. When pressure drop at inlet and outlet is over 10kPa, the effect of compressibility could not be neglected. This implies that the effect of compressibility in microchannels can be described better by pressure drop at inlet and outlet than Ma, which is in contrast to the practice in the conventional scale. At last, the viscosity heating effect was simply analyzed. It was found that the effect of viscosity heating increases with the increase of Re and decrease of size.
Investigation of Contribution Ratio Between NBTI and HC Effects in PMOSFETs Under Deep-Submicron Process
Authors: Wang Mu-Chun , Hsieh Zhen-Ying , Chen Shuang-Yuan , Huang Heng-Sheng
Published: June 2009

Quantifying the contribution of the hot carrier effect (HCE) and the negative bias temperature instability (NBTI) effect in PMOSFET device reliability is an urgent target, especially as the dual poly-gate implantation and the novel oxide growth recipe is derived. At this stage, the PMOS gate-oxide thickness is thinner than before, therefore, the implanted boron or BF2 is possible to penetrate from poly gate to surface channel. Furthermore, the implant source contains the plenty ionized hydrogen. This material is easily to be trapped in the gate oxide or bonded with the surface-channel silicon. The amount of interface state concentration, Nit, or oxide trap concentration, Not, is increased. As a result, the threshold voltage of the PMOSFET will be shifted away from the design target. Therefore, the source/drain current will be influenced and this PMOSFET will usually exhibit an unstable state. In the worst case, the IC chip will fail or stop working. This negative bias temperature instability (NBTI) effect has the tremendous impact to the PMOSFET performance.
Design of a 0.18um Stable Non-Volatile Boost Circuit in High/Low Temperature Operation
Authors: Wang Mu-Chun , Hsieh Zhen-Ying , Chen Chien-Chih , Chen Shuang-Yuan , Huang Heng-Sheng
Published: June 2009

In this work, we propose the P-MOS diode structure with triple-well process plus MIM capacitors, to establish two non-volatile boosters for flash memory products. Every connecting point in circuits, avoiding the occurrence of dielectric breakdown in gate oxide or p-n junction, was precisely conceived and examined. As the consideration of the system-on-chip (SoC), two stabilized-voltage circuits and two internal ring oscillators were built in. Additionally, to couple the voltage and to stabilize the voltage after several signal-transfer stages, obtaining the output voltage with DC 12V and DC20V, separately, as the input voltage is 3.3V, is necessary. The pumping time, while the high voltage is approached, is only several micro-seconds. The temperature effect with −25 ∼ 75°C range little impacts the booster voltages. The variation, due to temperature contribution, is less than 3%. By the way, this circuit design not only adopts the TSMC 0.18um process design kits, but includes some ESD protection circuits, in output terminals, to provide chip protection. It’s a full and efficient booster design with 0.18um CMOS process. The final dimension of this chip is around 705×978um2.
A 5.8GHz Band-Pass Filter With an Active Inductor Through 0.18μm Full-CMOS Process for Wireless Transceivers
Authors: Wang Mu-Chun , Hsieh Zhen-Ying , Ke Cheng-Yi , Chen Shuang-Yuan , Huang Heng-Sheng
Published: June 2009

Substituting the active inductor for the passive inductor to integrate the 5.8GHz bandpass filter into a system-on-chip (SoC) circuit is a feasible solution to reduce the filter chip area, increasing the application competition. The bandpass filter circuit in simulation with TSMC 0.18um CMOS process models and Agilent simulation software exhibits the good performance such as an input return loss (S11) of −34.26dB, an output return loss (S22) of −17.49dB, a bandpass gain (S21) of −4.33dB, a noise figure (NF) of 18.91dBm, a 1-dB compression point (P1dB) of −23dBm, a third-order intercept point (IIP3) of −15.83dBm, and the power dissipation in 19.44mW under 1.8V power-supply operation. In addition, the 3-dB bandpass bandwidth is 300MHz. The final dimension of this chip is approximate to 680×530μm2.
Design, Fabrication and Characterization of Nanostructured Fiber Arrays for Fuel Cell Applications
Authors: Gan Yong X. , Hyers Michelle L.
Published: June 2009

Design, fabrication and characterization of well-aligned porous nanofibers with large electroactive surface areas were performed. Highly ordered nickel-iron alloy nanofiber arrays were fabricated within porous anodic aluminum oxide (AAO) templates via electrodeposition. In order to further increase the electroactive surface area, dealloying was performed to extract the less noble metallic element, iron, from the nickel alloy to form porous structures. Electrocatalytic properties of the nanoarchitectured porous Ni nanofiber arrays were characterized by cyclic voltammetry (CV). Comparative studies on the electrochemical activities of the nanoarchitectured porous Ni fiber electrode in pure methanol and methanol sulfuric mixture solution were performed. The potential for methanol oxidation is about 0.4 V. It is found that sulfuric acid facilitates the oxidation of methanol. Preliminary studies on the electrocatalytic behavior of the nanoporous nickel in several other solutions containing sugar, orange juice, soy beam juice, tomato sauce were also performed. The stress state of the nanofiber in the AAO templates was derived as well.
Development and Application of a Precision Micro EDM System
Authors: Li Gang , Zhao Wansheng , Guo Rui
Published: June 2009

This paper presents the development of a micro-EDM system which is aimed to improve micro machining capability. The system consists of high precision X-Y-Z stages with quick response, a high precision granite machine body, a pulse power generator, a CCD microscopic computer vision system, etc. The X-Y-Z stages are driven by ultrasonic linear motors with a resolution as high as 0.05 μm. The granite machine body can reduce stray capacitance and absorb vibrations. RC pulse power generator can supply discharging energy as small as 10−9 J. Micro electrode can be measured with a resolution of 1.6 μm by the microscopic computer vision system online. In order to machine precision 3D microstructures, a special CAM software package based on the commercial CAD/CAM software Unigraphics (UG) is developed to generate tool path and NC codes and compensate the electrode wear. Experiments carried out on this machining system show that micro shafts with a minimum diameter of 6 μm and micro holes of 10 μm in diameter can be obtained stably. With the aid of the self-developed CAM software packages, complicated 3D microstructures are machined on this micro-EDM machining system.
Influence of SDBS on Stability of Copper Nano-Suspensions
Authors: Li Xinfang , Zhu Dongsheng , Chen Gang , Wang Xianju
Published: June 2009

Dispersion and stability of Cu nano-suspensions with dispersant is the important base for the study of rheology and heat transfer enhancement of the suspensions. This paper presented a procedure for preparing a nanofluid which was a suspension consisting of nanophase powders and a base liquids. By means of the procedure, Cu-H2O nanofluids with and without dispersant were prepared, whose sedimentation photographs were given to illustrate the stability and evenness of suspension with dispersant. Dispersion and stability of Cu nanoparticles in water were studied under different pH values and the concentration of sodium dodecylbenzenesulfonate (SDBS) dispersant by the method of zeta potential, absorbency and sedimentation photographs. The results show that zeta potential has very corresponding relation with absorbency, and the higher absolute value of zeta potential and absorbency are, the better dispersion and stability in system is. The absolute value of zeta potential and absorbency are higher at pH 9.5. SDBS can significantly increase the absolute value of the zeta potential of the particle surfaces by electrostatic repulsions, which leads to the enhancement of the stability of the Cu suspensions. The optimizing concentration for SDBS in the 0.1% copper nano-suspensions is 0.07%, which has the best disperse results.
Matthienssen’s Rule in Polycrystalline Metallic Nanofilms
Authors: Zhang Qing-Guang , Cao Bing-Yang , Zhang Xing , Takahashi Koji , Fujii Motoo , Zhu Ling-Yun
Published: June 2009

Matthiessen’s rule has been applied to analyze the simultaneously measured electrical and thermal conductivities of polycrystalline platinum nanofilms. The results show that the greatly reduced conductivities are mainly attributed to the grain boundary scatterings. By taking into account the background scattering and the grain boundary scattering, Mathienssen’s rule slightly underestimates the thermal conductivity, but obviously overestimates the electrical conductivity. By introducing an additional parameter characterizing electron scattering on the grain boundary in Matthiessen’s rule, the agreement between the theoretical predictions and the observed results are greatly improved. Further studies show that when the mean grain size is much smaller than the corresponding mean free path, the electrons’ behavior inside the grains becomes affected by the grain boundaries and the underlying assumption of independent scattering processes for Mathiessen’s rule will become invalid.
Influence of Microstructure on the Binder Ratio of B-TCP Tissue Scaffolds Using Selective Laser Sintering
Authors: Lin Liulan , Hu Qingxi , Zhao Li , Fang Minglun
Published: June 2009

The growing interest in scaffold-guided tissue engineering (TE) to guide and support cell proliferation in the repair and replacement of bone defects gave rise to the quest for a precise. Rapid prototyping (RP) has been identified as a promising technique capable of building complex objects with pre-designed macro- and microstructures. Calcium phosphate ceramics are biocompatible and may develop interactions with human living bone tissues. They are used clinically on the surface of orthopedic implants to improve primary fixation or in the form of porous blocks. The research focused on the macro and micro-structure of using the selective laser sintering (SLS) technique for creating porous tissue engineering scaffolds. The composite blends obtained by physical blending nano TCP and micro polymer powder binders. The SLS-fabricated test specimens were characterized using XRD and scanning electron microscopy. The total porous volume of the ceramics was over 70% and the pore size from several μm to 600μm. The results obtained ascertained that SLS-fabricated scaffolds have good potential for TE applications.
Effects of Substrate Properties, Film Thickness and Evaporation Rate on the Surface Roughness of Ultra Thin Titanium Films
Authors: Han Guoqiang , Jiang Zhuangde , Jing Weixuan , Zhu Mingzhi
Published: June 2009

Ultra thin (less than 50nm) titanium films with various thicknesses are systematically deposited on different substrates by electron-beam evaporation at various deposition rates in order to correlate flat titanium film surface roughness with deposition process parameters. In this paper, the influences of the substrate surface properties, film thickness and evaporation rate on surface roughness of flat ultra thin titanium films are clarified. In this study, distinct and abrupt steps on the film surface were fabricated by masks pasted on the substrate surfaces during the deposition process. The step can be scanned with stylus profilometer to reveal the height of the step (the thickness of the thin film). Ultra thin films with height 20–50 nm were routinely measured in this way. It is important to notice that ultra thin titanium films with different surface roughness but having the same film thickness can be obtained in a controllable way. Therefore, the control of substrate surface roughness, film thickness and evaporation process is essential to prepare ultra thin titanium films with desired surface properties in reproducible way for further biological and nanostructure investigations of these materials.