bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and Characterization of Piezoelectric Films of ZnO and AlN by RF Sputtering for RF MEMS Applications
Authors: Chandra Sudhir , Vir Singh Atul
Published: February 2012

In present work, we report preparation and characterization of piezoelectric films of zinc oxide (ZnO) and aluminum nitride (AlN) by RF magnetron sputtering using respective ceramic targets. The effect of ambient gas, substrate temperature, RF power and sputtering pressure has been studied to get highly c-axis oriented films for potential applications in micro-electromechanical systems. The films were characterized by X-ray diffraction technique to identify the crystallographic orientation. It was observed that the film deposited in pure Argon (Ar) ambient were amorphous or weekly crystallized with no preferred (002) orientation. On the other hand, the films prepared in Ar-O2 for ZnO were highly c-axis oriented. Similarly AlN films were observed to be oriented along c-axis perpendicular to substrate only when deposited in mixture of Ar-N2. To demonstrate the application of piezoelectric properties, an FBAR device (Film Bulk Acoustic Resonator) using ZnO thin film was fabricated. ZnO films are very sensitive to the chemicals used in the micro-electro-mechanical systems (MEMS) fabrication processes which include acids, bases and etchants of different material layers (e.g. SiO2, chromium, gold etc.). A specially designed mechanical jig was used for physically protecting the film during Si anisotropic etching process in potassium hydroxide solution. The potential applications of these films in various RF MEMS devices have been discussed.
Thermal Conductivity and Mechanical Properties of Natural Rubber Filled with Modified-Graphite
Authors: Ma Lian Xiang , Yan Hai Quan , Ke Jia Na , He Yan
Published: February 2012

In this paper, the thermal conductivities and mechanical properties of natural rubber which is filled with graphite and modified by acrylate are studied experimentally. It is found that the thermal conductivities and mechanical properties of vulcanizates are improved significantly. The thermal conductivity and mechanical properties of graphite-filled nature rubber which is modified by the mass ratio of 5:1 between graphite and monomers are best in 3 kinds of formulations.
Analysis of Influences of Processing Parameters on Filling Behavior in Microinjection Molding with a Hot Runner Nozzle
Authors: Gou Gang , Xie Peng Cheng , Yang Wei Min , Ding Yu Mei
Published: February 2012

The ability for polymer melt to flow into the microstructure is a crucial factor for successful molding in the microinjection molding of plastic parts. In this study, a simplified analytical model with a direct hot runner nozzle and was constructed to estimate the filling percentage of mold’s cavity. The filling behavior of polymer melt was observed by 3D simulation software Moldflow. The effects of the mold temperature, melt temperature, injection pressure, injection rate, and packing pressure on the filling behavior of polymer melt were investigated. Results revealed that the filling percentage increased with respect to the increase of mold temperature and melt temperature which didn’t exceed its degradation temperature. The injection pressure and packing pressure dramatically influence the filling percentage, and it made no sense to lift the injection speed to fill the cavity when the injection speed reached the relatively high values, and only processing parameter combined available could guarantee the perfect flow and filling for the microstructure.
Experimental Studies on Epoxy-Amine System Using Microwave and Conventional Curing Approaches
Authors: Sun Tao , Chang Xin Long , Lai Jian Wei
Published: February 2012

In this present work attempts have been made to study the difference between microwave heating and conventional thermal heating in curing the epoxy-amine system of di-glycidyl ether bisphenol-A(DGEBA) with the curing agent of 4,4′Diamino diphenyl methane(DDM). Curing behaviors and mechanical properties of the system were studied through a number of experiments. Differential scanning calorimetry (DSC) technique was implemented to measure the glass transition temperature and kinetic parameters, and fourier transform infrared spectroscopy(FT-IR) was used to analyse the cure reaction mechanism of the resin system. Finally, microstructure of microwave-cured materials was also studied by using a scanning electron microscope(SEM) in order to analyze the morphology of cured specimens.
Dynamic Modeling and Vibration Analysis of the Drum Washing Machine Based on Four-Terminal Parameter Method
Authors: Wu Jun Fei , Li Hui , Yang Xue Zheng , Zhang Xu Ping
Published: February 2012

In this study, the drum washer’s dynamic model has been conducted using Four-terminal parameter method. Firstly, the basic principles and advantages of the four-terminal parameters has been explained, and we have analyzed the vibration mechanism of the drum washer. Secondly, the drum washer was simplified ,and we extracted its dynamic model. Thirdly, we solve each of its components by using the four-terminal parameter method,and according to the connection between the components, determine each component and the system’s four-terminal parameters .Then, deduce the system’s matrix equations,get the complex steady-state response and steady-state response under sinusoidal excitation of the system. Last, input the drum washer’s actual parameters ,we can see that four-terminal parameter method dynamics model is correct. In a word, it is easy to analyze the vibration of complex systems. This paper is designed to provide theoretical support for the design of the drum washer’s damping device.
Numerical Simulation and Balance Design of Rubber Injection Mold Gating System Based on POLYFLOW
Authors: Chen Lian Shuai , Zhang Hui Min , Niu Jia Teng
Published: February 2012

Rubber injection molding is applied in more and more applications in rubber production process. Design of gating system is the most important in rubber injection mold design. Poor runner design will lead to uneven injection velocity and pressure which affect the size and shape and the quality of the rubber products. This paper first adopted POLYFLOW numerical simulation. Three different inlet flow rates for multi-cavity mold were simulated and analyzed by POLYFLOW software in this paper. Non-equilibrium gating system was further optimized by the calculation method of Balanced Gate Value and numerical simulation. The best inlet flow rate and the best runner size were ultimately obtained. It was proven that Numerical simulation results are of great significance for rubber injection mold design and injection molding processing parameter selection.
Anti-Icing Nanoparticle/Polymer Composite Coatings
Authors: Tang Xin De , Li Jun , Li Ling , Chen Hong , Kong Xiang Li
Published: February 2012

Nano calcium carbonate/polymer composite coatings were prepared and their anti-icing property was investigated. The anti-icing capability of the composites depends not only on their superhydrophobicity but also on the surface morphology. The result opens up possibilities for rational design of anti-icing coatings by tuning surface textures in multiple scales and provides a comprehensive framework for optimazing nanoparticle/polymer composite for a wide range of applications.
Vibration Analysis of Tripod of the Twin Tripod Sliding Universal Joint Based on ANSYS
Authors: Chang De Gong , Zong Rong , Liu Zhao Dong
Published: February 2012

Abstract. In this paper, taking the tripod of twin tripod sliding universal joint as three-dimensional solid model, it uses ANSYS to carry on the vibration analysis. We can obtain the first 10 natural frequencies, the stress and displacement frequency curve, the stress and displacement contour of tripod and some valuable conclusions by vibration analysis. So, it offers a theoretical reference for the optimization design and development of the twin tripod sliding universal joint.
Effects of Particle Size on the Rubber Mixing Process and Mechanical Properties of Compound
Authors: Lin Guang Yi , Gao Ben Fa , Wang Chuan Sheng
Published: February 2012

In order to improve the dispersion degree of carbon black and other additives, reduce consumption of energy and the temperature of discharging rubber compound, our research has been focused on preparation of rubber compound with different rubber particle size at filling coefficient of 0.6 and 0.7 in the mixer. The power consumption, the temperature of discharging rubber compound and the dispersion of carbon black were characterized in this study. The mechanical properties of the rubber compound have also been tested. The results indicate that reducing the particle size of rubber can reduce the consumption of energy and the temperature of discharging rubber compound and improve the mechanical properties, which is very important in rubber industry
Research of Low-Temperature Regeneration of Waste EPDM
Authors: Wang Chuan Sheng , Xie Qing Guo , Bian Hui Guang
Published: February 2012

In this paper, the research of regeneration of waste EPDM has been done on the basis of a lot of reading of literature and collecting of information. It has neither the pollution of gas emission during the recycling of rubber in dynamic desulfurization tank under high temperature and pressure, nor the high energy consuming during the recycling of rubber using regenerant under normal temperature and pressure. Eventually, the regeneration of waste EPDM under low-temperature became a reality.
Injection Compression Molding Process and Mould Design of Plastic Optical Lens
Authors: Bu Qiu Xiang , Zhu Jian Yi , Yin Qing Zhen
Published: February 2012

The characteristic of injection compression molding technology and the application of the technology in mould for the plastic optical lens were introduced. The structure and the work principle of the mould for optical lens were designed and described, The stress problem in the injection process was resolved, the deformation problem and dimensional accuracy of product were improved.
Numerical Study on Enhanced Paraffin/Air Heat Transfer with Extended Surface
Authors: Zhou Yan , Zheng Wen Juan , Fan Xi Yan , Chao Jun , Li Qing Ling
Published: February 2012

The extended surface is used to enhance paraffin/air heat transfer because of the paraffin’s poor thermal conductivity, and the heat storing and releasing capacity of paraffin heat storage layer with variety of extended surface are compared by numerical simulation. The results show that: the heat storage layer with vertical rectangular fin extended surface has stronger ability on the heat storage and release, and can more effectively improve the air flow velocity in the solar chimney power plant system with vertical heat collector. Due to the restrictions of manufacturing, the heat storage and release capacity is stronger when the heat storage layer surface area with vertical rectangular fin is from 3.4 times to 5.8 times compare to the flat-plate heat storage layer.
Study of Konjac Glucomannan Esterification with Dicarboxylic Anhydride and Effect of Degree of Esterification on Water Absorbency
Authors: Han Ben Chao , Zhang Chi , Yao Xue , Luo Xue Gang
Published: February 2012

Dicarboxylic anhydride esterified Konjac glucomannan (DCKGM) was prepared to reduce the unusual water absorbency of native Konjac Glucomannan (KGM). The dependence of degree of substitution (DS) on the reaction conditions and influence of the DS on water absorbency were studied. The esterification was conducted using refluxing KGM in hot acetic acid which contains phthalic anhydride and pyridine catalyst. The chemical structure and characteristic of DCKGM were analyzed by GPC-MALLS and FI-IR. The results showed that the water absorbency for DCKGM is inversely proportional to DS increase. DCKGM may be a promising biomaterial in application of drug carrier, heavy metal ion adsorption and functional packing materials.
Application and Research of Acoustic Emission Technology in the Tank Security Detection
Authors: Huang Yi Hu , Chong Hong Lei , Hu Man , Jia Xi Mei , Liu Wen Long , Ma Ji Xiang
Published: February 2012

The safety of the tank in duty is an important problem in engineering. Acoustic Emission testing is a dynamic online detection technology for non-destructive testing, which can provide continuous on-line status monitoring for equipments and give early damage warning. In the tank loading process, the sensors can detect the signals of the tank based on the principle of Acoustic Emission and determine the defect location. With this technology, we can monitor and evaluate the tank's safety in production.
The Optimization of Weighing and Feeding System for Powder in Mixer Feeding System
Authors: Li Yong , Wang Long , Tian Wei
Published: February 2012

This paper analyzes the commonly existing problems regarding to the weighing and feeding system for carbon black and powders in mixer feeding system and discusses the potential root causes. It presents a proposal of optimization measures which are critical for improving the quality of compound and shortening the mixing cycle.
Thermal Conductivity of Amorphous and Crystalline SiO2 Nano-Films from Molecular Dynamics Simulations
Authors: He Yan , Tang Yuan Zheng , Ding Man , Ma Lian Xiang
Published: February 2012

Normal thermal conductivity of amorphous and crystalline SiO2nano-films is calculated by nonequilibrium molecular dynamics (NEMD) simulations in the temperature range from 100 to 700K and thicknesses from 2 to 6nm. The calculated temperature and thickness dependences of thermal conductivity are in good agreement with previous literatures. In the same thickness, higher thermal conductivity is obtained for crystalline SiO2nano-films. And more importantly, for amorphous SiO2nano-films, thickness can be any direction of x, y, z-axis without effect on the normal thermal conductivity, for crystalline SiO2nano-films, the different thickness directions obtain different thermal conductivity results. The different results of amorphous and crystalline SiO2nano-films simply show that film thickness and grain morphology will cause different effects on thermal conductivity.
Numerical Investigation of the Effect of Rotors’ Geometric Structure on Mixing Properties of Continuous Mixer
Authors: An Ying , Yang Wei Min , Ding Yu Mei
Published: February 2012

In this paper, the three-dimensional flow field and dynamic mixing processing in the continuous mixer have been studied using the professional polymer processing finite element analysis software package Polyflow. A quantitative evaluation system which consisted of dispersion mixing and distributive mixing was used to evaluate the mixing properties in simulation. Based on these numerical simulations, the influences of rotors’ phase angle and cross-section on mixing properties were analyzed. The results show that the main contribution of phase angles focus on distributive mixing and the main contribution of rotors’ cross-sections focus on dispersion mixing.
Rules of Precedence as Basis to Generate Manufacturing Routes and Process Planning
Authors: Agostinho O.L. , Batocchio A. , Bento da Silva I.
Published: February 2012

This paper presents a methodology to generate manufacturing routes and operations using rules of precedence to provide logical approach in their dimensioning and chaining. The rules of precedence order and prioritize the knowledge of various manufacturing processes, taking into account the theories of machining, forging, assembly, and heat treatments; also, utilizes the theories of accumulation of tolerance and process capability, between others. The proposed methodology requires development of manufacturing data bases of manufacturing process , tolerances and capabilities, deviations of the machine tool cutting tool fixture device and work piece . The rules of precedence make viable the generation of manufacturing routings and operations, through the usage of structured knowledge, instead of tacit one .This approach allows the structured development of manufacturing routes, which can be deployed to engineers working in the areas of manufacturing engineering.
A New Methodological Approach for the Machining Process Planning
Authors: Romero F. , Bruscas G.M. , Serrano J.
Published: February 2012

This document presents a procedure for carrying out the step of selecting the locating surfaces and validating the setup, which is incorporated within a methodology for machining process planning that, unlike other classical approaches, deals with the problem from back to front. The procedure, which uses the typical tolerance graphs and tolerance transfer techniques based on the worst case, is applied first of all to the last setup from the alternative process plan that is being drawn up, and lastly it is applied to the first. This method allows us to consider the effects of the transmission of the variability among setups (machining stages) proposed by the multi-station variability models.
Assembly Work Instruction Deployment Using Augmented Reality
Authors: Serván J. , Mas F. , Menéndez J.L. , Ríos J.
Published: February 2012

The assembly of components in the aerospace industry is currently supported by procedures based on work instructions. This documentation describes both the sequence of operations to be performed by operators and fundamental parameters of operation. However, sometimes difficulties arise, either by the difficulty of interpreting the information or because the process is too complex. This communication shows the results of the Project MOON (asseMbly Oriented authOring augmeNted reality) developed by AIRBUS Military. MOON uses 3D information from the industrial Digital Mock-Up to generate assembly instructions and their deployment by applying Augmented Reality technology. A prototype was developed for the electrical harness routing in the frame 36 of the AIRBUS A400M.
Audits as a Manner of Conformity Assessment and Improvement Guidelines in the Organisation
Authors: Karkoszka T.
Published: February 2012

Audit, being a tool for nonconformities analysis, seems to be one of the main requirements for maintaining the management system in every organisation. It applies to every process independently on the size, complexity as well as character of the realised activities enabling the assessment of the correctness of the system solutions and indicating the guidelines and possibilities of their improvement.
Graphical Analysis of Improvements in Manufacturing Processes as Result of Kaizen Events
Authors: Rieger B.T. , Sebastián M.A.
Published: February 2012

Productivity is an important factor in any industrial production. Based on several concepts and philosophies such as Kaizen and others, it is possible to realize an increase of productivity. Since it is of great interest to know and to evaluate the improvement, a suitable method that allows not only analyzing the improvement of cost but also of time is of interest. Based on the value stream map (VSM) and the profile of cost and time (PCT) the author has developed the PECOTA method, a graphical method of analysis. The concept of investment in time and cost by PECOTA allows first-time analysis and evaluation of a change in a manufacturing process in an easy and fast way. The method includes also the possibility to define the limit of lean manufacturing with the current processes.
Maturity Determination of New Forming Processes Considering Uncertain Indicator Values
Authors: Weckenmann Albert , Akkasoglu Goekhan
Published: February 2012

The development of new forming processes primarily aims for increasing the process robustness and shortening the process chain. With the development of the novel Sheet-Bulk Metal Forming, cause-effect relationships are to be parameterized optimally and the economic efficiency of the manufacturing process is to be improved. The extensive and comprehensive development tasks often lead to an intransparent development status. Hence, operational and strategic decisions - particularly in the early development stages - are often made on the basis of subjective criteria and a high information uncertainty. This often results in wrong decisions as well as subsequent cost-intensive modifications in the design of expensive forming tools and forming machines. Based on a designed maturity method relevant indicators for the early maturity assessment and thus cost-reduced improvement of the development status of new forming processes are defined in this paper. The maturity here reflects the phase dependent development status. By providing a uniform basis of maturity indicators a comparable evaluation of the development status becomes enabled. The validity of the maturity assessment is enhanced by considering the information uncertainty by use of Fuzzy Logic. An exemplary maturity determination is performed within the development of the Sheet-Bulk Metal Forming.
Structure Design of a Novel Micromachinined Tuning Fork Gyroscope with High Robustness
Authors: Chen W.P. , Yang Yi Bo , Yu Y.
Published: February 2012

A novel silicon based dual-mass vibrating tuning fork vibratory gyroscope (TFG) with differential capacitor structure is designed in this paper. the U-shaped beam is adapted to connecting the two decoupling movement of the framework structure in order to achieve the independent of the movement of drive direction and sense direction. The TFG structure is also optimized to further reduce the mechanical coupling of the device. The drive combs are designed on the mass, while the sense combs are designed on the frame. All the combs in this gyroscope are dominated by slide-film air damping in order to lower the air damping. This gyroscope is designed to obtain robust operation against variations under atmospheric pressure condition. The TFG is tested at atmospheric pressure with a sensitivity of 17.8mV/◦/s and a linearity of 99.989%, capacitance structure sensitivity is 21.5αf/◦/s with an equivalent noise angular rate of 0.028◦/s/Hz1/2, respective.
A High-Order Curvature-Compensated Bandgap Voltage Reference for Micro-Gyroscope
Authors: Li Qiang , Tan Xiao Yun , Wang Guan Shi
Published: February 2012

The reference is an important part of the micro-gyroscope system. The precision and stability of the reference directly affect the precision of the micro-gyroscope. Unlike the traditional bandgap reference circuit, a circuit using a temperature-dependent resistor ratio generated by a highly-resistive poly resistor and a diffusion resistor in CMOS technology is proposed in this paper. The complexity of the circuit is greatly reduced. Implemented with the standard 0.5μm CMOS technology and 9V power supply voltage, in the range of -40~120°C, the temperature coefficient of the proposed bandgap voltage reference can achieve to about 1.6 ppm/°C. The PSRR of the circuit is -107dB.
Analysis and Improvement of a 3 Axis Accelerometer
Authors: Wang Shi Tao , Jia Yu Bin , Zhang Bin Zhen , Liu Xue Song , Huang Qin Wen , Hao Yi Long
Published: February 2012

In this paper, an integrated 3-axis MEMS accelerometer was analyzed. Because of asymmetrical structure, z-axis sensing element, which was imbedded in the proof mass of lateral accelerometers, had large mechanical coupling. Simulation result showed that the cross talk in z-axis was as high as 64.3%. To solve the problem, a fully symmetrical structure with vertical springs was adopted in z-axis sensing element. The movement of z-axis was linear vertical displacement instead of torsional displacement. Simulation results showed there was no obvious cross talk in z-axis sensing element.
A 19 Element Hexagonal Actuator Arrangement Continuous Face-Sheet MEMS Deformable Mirror
Authors: Wang Wei Min , Tao Feng Gang , Zhang Jian Fei , Yao Jun
Published: February 2012

A new hexagonal actuator arrangement continuous face-sheet MEMS deformable mirror is proposed, a mirror array with 19 elements is fabricated by a surface micromachining process. This design has a good fitting capability and a fast dynamic response. The fabricated sample is tested by an optical profiler. Simulation and test results indicate that it has a small aperture size, a high fill factor, a fast response time and a high working bandwidth. This new device provides a possibility of manufacturing a large-actuator-count DM for high speed wavefront control.
Design and Simulation of Multi-Microchannel for Thermal Wind Sensor
Authors: Hong Rong Sen , Lou Wen Zhong , Liu Hui Chao , Zhao Yue
Published: February 2012

This paper describes novel multi-microchannel, which is the major component of wind velocity and direction sensor based on MEMS technology. The multi-microchannel built in a cylinder, and the channels have been optimized to produce a flow rate that depends on the wind direction according to a cosine function. When two such cylinders placed orthogonally in wind condition, wind speed and direction can be inferred from flow rate data measured from the channels. With the help of Fluent simulation software, this paper not only provides the design ideas of multi-microchannel but also proposes one design approach which meets the practical needs.
Study of High Sensitivity Sensor Based on the Principle of Photoionization
Authors: Niu Kun Wang , Liang Ting , Yang Fang , Meng Qing , Wang Kai , Xiong Ji Jun
Published: February 2012

The quality of designing structure and properties of sensor photoionization room，directly determines its weak signal detection sensitivity detection and effecting ionization chamber detection efficiency .The paper experiments on four factors of affect the sensitivity of sensor. The results show that: the signal intensity proportional to the area of the ionization chamber; signal intensity goes up with the increase of bias voltage, and with bias voltage into a square the relationship; signal strength was first increased and then decreased with the growth of the distance between electrodes; signal strength was first increased and then decreased. With the growth of light-driven power.
Air Gap Flux Density for the Planar Motor
Authors: Hao Xiao Hong , Li Xue Kang , Zhou Wu , Peng Bei
Published: February 2012

An analytical method was presented to predict the three-dimensional (3-D) magnetic flux density distribution in the air gap produced by NdFeB permanent magnets of the planar motor. First, the analytical model of the planar motor was established, and Laplace equations of magnetic scalar potential and a series of boundary conditions were given. Then, the analytical expressions of magnet field strength and magnet flux density were obtained in the air gap of produced by NdFeB permanent magnets by the method of separation of variables. Finally, Comparisons the analytical results and finite element results, and the error never exceed five percent. Therefore, high precision has been derived. The analytical field results provide a basis for comparative studies, design optimization, and machine dynamic modelling of the planar motor.
A High-Performance Mash Fourth-Order Sigma-Delta Modulator
Authors: Liu Wen Yan , Zhang Bin , Chen Long , Gao Chao , Liu Xiao Wei
Published: February 2012

This paper reports on a system level design and analysis of a mash fourth-order sigma-delta (ΣΔ) modulator. Compared with a high-order single-loop ΣΔ modulator (ΣΔM), there’s no need to consider about the system stability of a mash ΣΔM, which has the advantages of better signal to quantization noise ratio (SQNR). System level simulation results indicate that the SQNR is 122.0 dB, and the effective number of bits (ENOB) is 19.97 bits when the over sampling ratio (OSR) is 128.
Investigation on Transmittance and Uniformity of Light Diffuser Plate of Scattering Optical Transmission Polymer
Authors: He Xiao Xiang , Wu Da Ming , Zhang Ya Jun , Zhuang Jian , Zheng Xiu Ting , Zhou Yang
Published: February 2012

In this paper, the relations between scattering intensity and the radius of scattering particles, the refractive and the wavelength have been studied based on the MATLAB software, and the relations between the concentration of the particles, the radius and the refractive and the optical properties of diffuser have also been simulated by the Light Tools software based on the Monte-Carlo Method. The results show that with the increasing of radius and the wavelength, the distribution of scattering light energy gets concentrated. With the increasing of the particles, the transmittance decreases, and the uniformity increases first and decreases later. With the increasing of radius, the transmittance decreases. With the increasing of the index of refractive, the transmittance increases first and decreases later.
Research on Two-Dimensional Scanning Characteristics of MEMS Resonant Mirror
Authors: Zhang Chi , Chen Yun Han , You Zheng , Huang Hu
Published: February 2012

A two-dimensional MEMS resonant mirror is presented in this paper, which is capable of scanning a laser beam two-dimensionally in the both vibration modes. Based on the MEMS resonant mirror, a simulation method is presented to study the two-dimensional scanning characteristics. The scanning time of a frame is obtained and the impacts on the scanning time of a frame by the scanning parameters are simulated and analyzed. The simulation results have a great significance for the two-dimensional MEMS resonant mirror in space applications.
A Ground Target Positioning Method Facing Small UAVs
Authors: Guo Qi , Liu Shao Peng , Xiong Wei , Zhou Zhao Ying
Published: February 2012

Aiming at the problem that the dynamic attitude of small UAVs can’t be measured accurately, this paper describes a ground target positioning method based on the multi-images forward intersection. The parameters of the corresponding image rays are carried out in the local geographic coordinate system, and then these parameters are used to get the target 3-D coordinates. The flight tests have been finished. The test system is composed of a small UAV with a wingspan of 1.2 meters, a miniature vidicon and the micro autopilot developed by our laboratory. The miniature vidicon is calibrated with the active method and a red target is placed on the ground beforehand. In flight, the flight information including attitude, position .etc, is measured and recorded, and the video is collected isochronously. The error of the target position is about 5 meters at the flight height of about 250 meters.
Design and Fabrication of a MEMS Flexural Plate Wave Device Based on LTO/ZnO/LTO/Si3N4 Multilayered Composite Membrane
Authors: Xue Ming Xin , Liu Meng Wei , Li Xin , Li Jun Hong
Published: February 2012

The MEMS A0mode Lamb wave (flexural plate wave) ultrasonic devices have been shown to be extremely useful for sensor and actuator applications. The design and fabrication process of a MEMS flexural plate wave device based on the LTO/ZnO/LTO/Si3N4multilayered composite membrane are presented. The flexural plate wave was respectively launched and received by both Al interdigital transducers. In order to reduce the stress of the thin membrane induced mainly by the in-plane compressive stress of ZnO film, two fabrication process of DC and RF magnetron sputtering were used to deposit the ZnO films, respectively. The FPW device based on LTO(0.2μm)/ZnO(1μm)/ LTO(2μm)/Si3N4(0.5μm) thin membrane was fabricated. The center frequency of the MEMS flexural plate wave device is measured at 3.69MHz, which agrees with the theoretical predictions.
Design and Simulation for Tri-Axial Piezoresistive MEMS Accelerometer
Authors: Liu Meng , Zhang Wei , Hao Yi Long
Published: February 2012

This paper presents analytical models for tri-axial accelerometer based on one seismic mass and eight beams. The model makes it possible to better understand and to predict the behavior of the accelerometer. The accelerometer discussed in this paper was designed to measure high g-forces in every single axis. We use finite element mechanics analysis and design for optimization of the device structure. FEA software ANSYS was used to simulate the behavior of the accelerometer when it was subjected to static high-g forces. The analytical results of simulation and theoretical demonstrate that the accelerometer we designed is feasible.
Design and Simulation of Micro-Power Generator Based on Piezoelectric Effect for MEMS Devices Applications
Authors: Chou Xiu Jian , Zhang Ya Ting , Guo Mao Xiang , Guo Tao , Xiong Ji Jun
Published: February 2012

Piezoelectric thin films cantilevers with a central Si mass are designed for harvesting vibration energy applications. Through the theoretic analyzer and MATLAB simulation, the displacement, resonance frequency and maximum stress dependent of the different structure parameters of micro-power device are obtained. It shows that increasing the quality of mass and the length of microcantilever, decreasing the width and thickness of microcantilever can realize the low-frequency resonance and maximum power in actual design. The static and mode analysis of the theory model are done by using Ansys 11.0. The results can provide guidance for the design and fabrication process of micro power generator.
Structures and Dielectric Properties of (Pb, La)(Zr, Ti)O3 Antiferroelectric Thick Films Prepared by Different Sintering Procedures
Authors: Geng Wen Ping , Chou Xiu Jian , Lv Yong Bo , Xiong Ji Jun , Zhang Wen Dong
Published: February 2012

(Pb,La)(Zr,Ti)O3antiferroelectric thick films were prepared on Pt (111)/ Ti/SiO2/Si (100) substrates by a sol-gel process. The effects of single annealing and multistep annealing on the structures and electric properties of the films were investigated. The crystal orientation and structure of the antiferroelectric thick films were studied. The thick films by multistep annealing have higher (100)-preferred orientation than them by single annealing. The surface of the films was more smooth, compact and uniform by single annealing. The antiferroelectric nature of the (Pb,La)(Zr,Ti)O3antiferroelectric thick films by various sintering procedures was demonstrated by P(polarization)-E(electric field) and C(capactitance)-E(electric field). The temperature dependent of the dielectric constant and loss was measured under the frequency 1, 10, and 100 kHz and comparing with traditional signal annealing, the films have phase transition from antiferroelectric state to paraelectric state by multistep annealing.
Effects of Different Package Structures on Thermal Properties of High Power White LED
Authors: Sun Zhe Ran , Wu Da Ming , Zhang Ya Jun , Zhuang Jian , Dang Kai Fang
Published: February 2012

The characteristics of several package structures of high power white Light emitting diode (LED) are described in this paper. The influence of different structures on thermal properties is analyzed. Forward voltage method is used to test the thermal resistance of LED chips.
Size-Dependence on Load Properties of a Silicon Nanobeam
Authors: Wang Jing , Zhang Hong Yan
Published: February 2012

A semi-continuum approach is developed for mechanical analysis of a silicon nanobeam, which captures the atomistic physics and retains the efficiency of continuum models. Young’s modulus of the silicon (001) nanobeam along [100] direction is obtained by the developed semi-continuum approach, which decreases dramatically as the size of a silicon nanobeam width and thickness scaling down. Taking into account the variations of Young’s modulus at different size, the load properties of the nanobeam is computed. The model predicts the deflection of the nanobeam is size-dependence. Introduction
Study on Anodic Bonding Process of Slender Vitreous Body
Authors: Pan Ming Qiang , Chen Li Guo , Chen Tao , Wang Zhen Hua , Sun Li Ning
Published: February 2012

With the development of MEMS technology, the pressure sensors, one of mature MEMS devices, are expected to better performance. In order to improve sensors performance, supporting vitreous body shape is elongated and thinned. But the variety of the vitreous body shape brings the new difficulties for anodic bonding between the vitreous body and the silicon during the sensors production, and causes that the common bonding process conditions are unavailable and bonding failure rate dramatically increases. Therefore, this article analyzes the bonding process between slender vitreous body and silicon, and researches on the influence of the vitreous body variety on the pressure, temperature and voltage. The results showed that the bonding is the best when the cantilever elastic deformation is less than 0.5mm, interface temperature loaded from the silicon is 415°C and the voltage 1200V is loaded from the position near H=2mm.
An Alignment Method for Lift-Off on Shallow Grooves in Transparent Substrates for Integrated Dual Grating Structures
Authors: Feng Jin Yang , Chen Feng , Shang Yuan Fang , Ye Xiong Ying
Published: February 2012

In this Paper, we Propose an Alignment Method for Lift-Off on Shallow Grooves in Transparent Substrates without an Extra Mask. An Assistant Metal Layer Was Deposited on the Glass Substrate with Grooves to Increase the Reflectance, and then a Layer of Photoresist for Lift-Off Process Was Coated and Patterned Aligning with the Shallow Grooves. We Compared the Effect of Aluminum and Chromium Films with Different Thickness as Reflecting Layers. an Aluminum or Chromium Film with the Thickness Larger than 10nm Provides High Enough Image Contrast of Profile of the Alignment Marks Beneath the Photoresist. the Image Contrast of Contour Profile of the Marks Was Enhanced as the Thickness Increased. Lift-Off Process Was then Implemented on the Assistant Reflecting Layer. With a 20nm Cr Layer, we Successfully Did Lithography and Finished the Lift-Off Process to Pattern a Cr/Au Layer on Shallow Grooves in a Glass Wafer. Finally, the Assistant Cr Layer Was Removed Using Dry Etching. the Assistant Metal Layer Has No Undesirable Influence on the Following Process and the Device Property.
Micro-Machined Electrochemical Seismic Sensors with Interdigital Electrodes
Authors: Li Guang Bei , Chen De Yong , He Wen Tao , Wang Jun Bo
Published: February 2012

An electrochemical seismic sensor (ECSS), which consists of interdigital electrodes immersed in electrolyte solution, based on MEMS technology is studied theoretically and experimentally in the paper. The output current of the sensor is employed to measure the ground motion. The device has a small size, simple design and fabrication process with low cost. Preliminary test results show that the novel electrochemical seismic sensor has satisfactory characteristics.
Maturity Model for the Development of New Forming Processes Applied to the Sheet-Bulk Metal Forming
Authors: Weckenmann Albert , Akkasoglu Gökhan
Published: February 2012

Forming processes are characterized by high cost-effectiveness due to high material utilization and short forming process time. Therefore the development of new forming processes aims for overcoming the current process limitations to produce function extended components with a wider range of application and lower manufacturing costs. The comprehensive and complex development investigations of cause-effect relationships and interdependencies lead to an intransparent development status, whose assessment is often based on undefined and not reproducible criteria. This can result in wrong decisions with vain modifications that require subsequent changes associated with an increased effort. A valid characterization of the development status of new forming processes by maturity determination in early development phases can detect improvement potentials in order to apply effective measures with reduced efforts. Maturity models provide essential indicators and assign their values to maturity levels, whereby a uniform assessment base is created and comparability of the determined maturity values is ensured. On the basis of a combined reference model maturity-related indicators for assessing the development status of new forming processes are defined. The designed maturity model has been applied in the development of the Sheet-Bulk Metal Forming.
Temperature Control during the APN-Process on the Steel 1.3343
Authors: Lizunkova Yana , Burov Sergey , Hassel Thomas , Bierbaum Marten Sebastian , Bach Friedrich Wilhelm
Published: February 2012

Nitride layers on the high-speed steel 1.3343 were produced by means of transmitted plasma arc. The surface treatment with plasma arc leads to high thermal stress reliefs caused by the tracing point of the arc. To use the plasma arc to build up a nitrided layer without a deep heat penetration of the base metal requires a good knowledge of the temperature profile on and under the surface. The investigations show that the steel needs a stable temperature on the surface to reach maximum nitrogen input. At the same time the surface temperature must not reach the melting point of the material. To satisfy these two conflicting conditions an accurate temperature control is necessary. Surface temperatures, temperatures in the bulk and under the surface were measured by conductive and thermographic methods and were correlated with investigations of the resulting metallographic structure. It was shown that the temperature distribution in and under the surface zone during the atmospheric plasma-nitriding shows a large gradient and the material temperature at a depth of 100 µm is not more than 200 °C.
Manufacturing of Sheet Metal Components with Variants Using Process Adapted Semi-Finished Products
Authors: Merklein Marion , Plettke Raoul , Schneider Thomas , Opel Simon , Vipavc Daniel
Published: February 2012

Manufacturing of functional sheet metal products by forming can be realised with the application of conventional bulk forming operations on sheet metals. The challenges of those sheet bulk metal forming processes are high resulting forming forces and the demand on a specific control of material flow. To meet these challenges well-directed thinning of blanks as well as accumulations of material to form functional elements is employed. Due to local loads, simultaneous 2D and 3D stress and strain states occur. Process adapted semi-finished products, containing a defined sheet thickness characteristic, are formed in the presented work by the technologies upsetting and orbital forming. Orbital forming is an incremental bulk forming operation to decrease the forming zone extension and consequently the required process force. Afterwards a process combination of deep drawing and upsetting in order to manufacture a cup-shaped workpiece with external gearing is presented. The results of this integrated single-stage forming process are discussed and subsequently the potential to enhance the process limits is shown by using process adapted semi-finished products.
Analysis of Roll Gap Heat Transfers in Hot Steel Strip Rolling through Roll Temperature Sensors and Heat Transfer Models
Authors: Legrand Nicolas , Labbe Nathalie , Weisz-Patrault Daniel , Ehrlacher Alain , Luks Tomasz , Horský Jaroslav
Published: February 2012

This paper presents an analysis of roll bite heat transfers during hot steel strip rolling. Two types of temperature sensors (drilled sensor /slot sensor) implemented near roll surface and heat transfer models are used to identify in the roll bite interfacial heat flux, temperature and Heat Transfer Coefficient HTCroll-bite during pilot rolling tests. It is shown that: - the slot type sensor is much more efficient than the drilled type sensor to capture correctly fast roll temperature changes in the bite during hot rolling but life’s duration of the slot sensor is shorter. - average HTCroll-bite, identified with roll sensors temperature signals is within the range 15-26 kW/m2/K: the higher the strip reduction is, the higher the HTCroll-bite is. - scale thickness at strip surface tends to decrease heat transfers from strip to roll in the roll bite. - HTCroll-bite appears not uniform along the roll-strip contact, in contrast to usual assumptions made in existing models - Heat dissipated by friction at roll-strip interface and its partitioning through roll and strip respectively seems over-estimated in the existing thermal roll gap model [1]. Modeling of interfacial friction heat dissipation should be reviewed and verified. The above results show the interest of roll temperature sensors to determine accurately roll bite heat transfers and evaluate more precisely the corresponding roll thermal fatigue degradation.
Cooling of a Rotating Cylinder by a Subcooled Planar Jet - Influence of the Surface Velocity on Boiling Regime
Authors: Devynck Sylvain , Gradeck Michel , Bellot Jean Pierre , Denis Sabine , Varlez Michel , Benard Thierry
Published: February 2012

Cooling from impinging jet is nearly compulsory in steel industry processing especially in Run Out Table processing and steel tube production because of the high heat transfer provided by the boiling of the subcooled water jet. As far as metallurgical phase transformations, residual stresses and deformations in the workpiece are concerned, the temperature drop during cooling must be controlled thanks to a full understanding of the heat transfer mechanisms. One of the main characteristic using jet impingement is that the transition boiling regime may exist for very high superheat and thus the Leidenfrost temperature is higher than in pool boiling; consequently, boiling curves generally have a particular shape in the transition boiling regime which is usually called “shoulder of flux”. In this study, an innovative experimental quenching device has been used for analyzing the effect of the wall velocity of the surface to be cooled on the boiling curves (i.e. heat transfer) and we especially point out that the “shoulder of flux” (i.e. transition boiling regime) is strongly dependent on the surface to jet velocity ratio (r*). We found that a very small increase of the wall velocity has a high influence on shoulder of flux collapse.
Implementation of the Axially Symmetrical and Three Dimensional Finite Element Models to the Determination of the Heat Transfer Coefficient Distribution on the Hot Plate Surface Cooled by the Water Spray Nozzle
Authors: Malinowski Zbigniew , Telejko Tadeusz , Hadala Beata , Cebo-Rudnicka Agnieszka
Published: February 2012

Plate and strip hot rolling lines are equipped with water cooling systems used to control the deformed material temperature. This system has a great importance in the case of thermal - mechanical deformation of steel which is focused on formation a proper microstructure and mechanical properties. The desired rate of cooling is achieved by water spray or laminar cooling applied to the hot surface of a strip. The water flow rate and pressure can be changed in a wide range and it will result in a very different heat transfer from the cooled material to the cooling water. The suitable cooling rate and the deformed material temperature can be determined based on numerical simulations. In this case thermal boundary conditions have to be specified on the cooled surface. The determination of the heat transfer coefficient distribution in the area of the water spray nozzle would improve numerical simulations significantly. In the paper an attempt is made to determine the heat transfer coefficient distribution on the hot plate surface cooled by the water spray nozzle. In the inverse method direct axially symmetrical and three dimensional solutions to the plate temperature field have been implemented. The computation time and the achieved accuracy have been compared for five cases. The studied cases differed in the maximum value of the heat transfer coefficient in nozzle spray axis and its distribution in the cooling time.