bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-Dimensional Measurement System Based on Micro Stereovision
Authors: Pei Wei , Zhu Yong Ying , Liu S.X. , Wen J.M.
Published: April 2014

With vision feedback the binocular micro stereovision system based on stereo light microscope (SLM) makes it possible to achieve 2D/3D high accuracy auto-positioning, 3D information extraction, 3D shape reconstruction and 3D measurement. Therefore, it is extensively used in micro robot navigation, micromanipulation, micro assembly and bioengineering, etc. To improve the key problems of low accuracy, refraction and occlusion in micro stereovision measurement, a novel micro stereo vision system is built based on optical theory and digital image processing. Then, the nonlinear correlation between optical paths of the micro stereo vision system is studied and the environment adaptive nonlinear model is established. On this basis, the coupling mechanism of multi-refraction and occlusion with micro-projection nonlinear model is proved, and multi-refraction variable refractive index correction and micro stereo occlusion reconstruction algorithms are developed. It realizes synchronization observation in larger field of view, rapid non-contact accuracy positioning and 3D measurement based on stereovision to solve the pivotal problems of accuracy positioning and measure in the chip encapsulation, micro assembly and the micro manipulation.
Error Compensation Technology of Semi-Strapdown MEMS Inertial Measurement System
Authors: Li Jie , Zhu Jing De , Hou Li Peng , Liu Jun
Published: April 2014

Semi-strapdown inertial measurement method provides a new solution for the high-precision measurement on flight attitude of high-spinning ammunition, while the specific set of components in the semi-strapdown application will cause a series of errors. This paper mainly analyzes the generation mechanism of motor speed fluctuation error and the misalignment error in coupling axis. Then the instantaneous motor speed measurement method based on the high-precision gyroscope is designed and the misalign model of coupling axis is set up, MEMS inertial measurement area centripetal force equation under the condition of high speed is worked out, and accuracy error parameters affecting the measurement are obtained. Finally, the paper provides corresponding error compensation method and comparative tests are conducted. The results show that the compensated system improves the accuracy of attitude angle calculating and the error has been effectively suppressed.
The Design and Realization of Micro Induction Heater for the Thermal Bubble Generation
Authors: Hou Yue Peng , Liu Ben Dong , Yang Jia Hui , Cai Ping
Published: April 2014

This paper presents a micro induction heater based on the principle of induction heating. The liquid contact with the micro heater core directly and heated by the eddy current effect. The heating effect of the micro heater is simulated with the software of COMSOL. The simulation results indicate that the temperature of the micro heater core can reach to 540K in 0.9s while the current is 0.7A and the power frequency is 200 kHz. The relations between the heating effect and the micro induction heaters parameters such as the current, the AC power frequency and the coils parameters are studied in the simulation respectively. The prototype of the micro heater has been fabricated and the experimental test has carried with the micro heater. The experiments indicated that the micro heater can generate thermal bubble in 0.3s while the 1.0A high frequency current passes through the heater coil. The micro induction heater can be applied to a variety of thermal bubble devices, such as micro injector, micro switch and micro pump.
Sliding-Mode Control for Piezoelectric Actuators Based on Hysteresis Observer
Authors: Wei Qiang , Zhang Chao , Zhang Dong , Zhang Cheng Jin
Published: April 2014

A sliding-mode control (SMC) scheme based on hysteresis observer is designed in this paper for precision trajectory tracking of piezoelectric actuators. A mathematical model considering the dynamics of a mass-spring-damper trio and the hysteresis friction force describing the parameters of bristle stiffness, damping and viscous is proposed. A lumped uncertain function composed of the mechanical parameters, displacement and its deriviation, hysteresis friction force and external load force is estimated by a hysteresis observer. An asymptotically stable sliding surface is defined. Lyapunov stability theory is applied to guarantee the asymptotical stability for the trajectory tracking error. Experiments are conducted to validate the effectiveness of the proposed method. Results show that a satisfied tracking response to a sinusoidal trajectory is achieved, and the positioning errors under a triangle scanning contour are dramatically reduced compared with the traditional SMC.
An Electromechanical Tunable Grating on Silicon-on-Insulator Platform
Authors: Gao Xu Min , Shi Zheng , Li Xin , He Shu Min , Zhu Hong Bo , Wang Yong Jin
Published: April 2014

We report here the design and fabrication of an electromechanical tunable grating on silicon-on-insulator (SOI) wafer. The tunable grating consists of a submicron electrostatic comb actuator and an expandable freestanding grating. Rigorous coupled-wave analysis (RCWA) method is utilized to analyze the optical responses of freestanding grating with different periods and filling factors. Obvious shift of the resonant peaks is obtained by changing the grating period and the grating filling factor. The electromechanical tunable grating is realized on the silicon device layer by a combination of electron beam (EB) lithography, deep reactive ion etching (DRIE) and wet etching. Scanning electron microscope (SEM) micrographs indicate that the grating is well fabricated. Via applying biased voltage, the force generated by the electrostatic comb actuator can modulate periods and filling factors of the freestanding grating. The electromechanical tunable grating with simple fabrication process shows bright prospects for optical telecoms and miniaturized spectrometers.
Sliding Mode Control for Electromagnetic Actuation MOEMS Scanning Mirror
Authors: Zhou Hui , Chen Li , Wang Jun Bo , Zhang Zuo Jun , Chen Dan Hua
Published: April 2014

Sliding Mode Control (SMC) based on exponential switching law for electromagnetic actuation MOEMS mirror was proposed. This technique relies on the movable mass and the dynamics of the sliding surface. In such a way, the generated actuation tracks possible changes in the mechanical behavior induced by external factors (humidity, temperature, pressure, etc.). Stability of the proposed method is proved by Lyapunov second method. The system level model is established and simulated using MATLAB/Simulink. Simulation results show that: the scanning angle converges to reference value in only 0.45 seconds when using exponential switching law, which is decreased 55% compared with that using proportional switching law, and the sliding surface is much smooth too; the tracking error less than 0.25%, and sliding surface jittering in the range of 0.5. The proposed SMC controller can realize accurate control of mirror and having high performance and robustness in the presence of external disturbances and also can be applied to the closed-loop control of other vibrating devices.
One-Time Use MEMS Metal Bridge Igniter Based Electro-Explosive Solid Off-On Switch
Authors: Ding Xu Ran , Lou Wen Zhong , Li Kang , Zhao Yue , Wang Gui Lei , Liu Peng
Published: April 2014

A novel type of single use bi-stable MEMS solid off-on switch based on metal bridge igniter is described and its performance test results are presented. The switch mechanically connects a couple of comb electrodes which belong separately to different metallic lines. Switching between the two stable states (off and on) is accomplished by a voltage pulse supplied by an energy storage capacitance through a metal bridge igniter above the electrical lines to be connected. The switch can be driven by external signal and its predicted lifetime is very long, therefore the switch can be used for long term store systems.
Influence of Nano Abrasive on Chemical Mechanical Ultra-Precision Machining of Sapphire Substrate Surfaces
Authors: Niu Xin Huan , Huang Ya Huan , Zhou Jian Wei , Han Li Ying , Yuan Gai Hong
Published: April 2014

Sapphire (α-Al2O3) single crystal combines many good mechanical and optical properties that make it become the material of choice in a variety of modern Hi-Tech applications The use of CMP technique can produce high quality surface finishes at low cost and with fast material removal rates. In CMP process, nanoabrasive is very important parameters in determining the removal rate. In this paper, the influence mechanism of nanoabrasive on sapphire substrate CMP was analyzed deeply. The main kinetics processing was discussed in detail. According to sapphire substrate properties, alkali slurry was chosen and the mix of SiO2 and Al2O3 sol was selected as nanoabrasive, and the particle size was 20~30nm. The results show that adding nanoalumina with the concentration of 20ml / L in the main abrasive can make the chemical action balance with the mechanical action in the CMP process, so that the substrate removal rate is well improved, and the surface roughness can be reduced to 0.236nm by adjusting the process parameters and slurry ratio. Such data meets the super smooth requirement and the optimal sapphire surface can be gotten. So such slurry with mixed abrasive can be as rough polishing slurry and can improve the polishing efficiency.
Novel Integrated Demultiplexer with the Bragg Grating Structure Based on Surface Plasmon Polaritons
Authors: Luo Liang Bing , Liang Rui Sheng , Li Teng Long , Mo Wen Hao , He Ming Jia
Published: April 2014

A novel demultiplexer based on surface plasmon polaritons with the Bragg structure has been proposed and numerically investigated. The finite difference time domain method with perfectly matched layer absorbing boundary condition is adopted to simulate and study their properties. By introducing Bragg grating structure in the couple area, high extinguish ratio can be achieved. The extinction ratio in 1550nm was 27.5db. Meanwhile, the photonic device can be made in the way of high level of integration, because SPPs has the ability of strongly localizing the signal mode in the area beyond the limit of diffraction. The longitudinal dimension of this demultiplexer was 650nm. The demultiplexer may become a good choice for the design of devices in highly integrated optical circuits.
Artifacts in KPFM in FM, AM and Heterodyne AM Modes
Authors: Ma Zong Min , Mu Ji Liang , Tang Jun , Xue Hui , Zhang Huan , Xue Chen Yang , Liu Jun , Li Yan Jun
Published: April 2014

In this paper, the crosstalk in potential measurements caused by the topographic feedback and the resonance frequency in Kelvin probe force microscopy (KPFM) was investigated in frequency modulation (FM), amplitude modulation (AM) and heterodyne amplitude modulation (heterodyne AM) modes. We showed theoretically that the distance-dependence of the modulated electrostatic force in AM-KPFM is significantly weaker than in FM-and heterodyne AM-KPFMs. We experimentally confirmed that the crosstalk in FM-KPFM and heterodyne AM-KPFM is weak than that in AM-KPFM due to the bigger difference of the modulated frequencies in topographic and potential measurements in FM and heterodyne AM-KPFMs. We also compared the corrugations in the local contact potential difference (LCPD) on the surface of Si (001) show that difference on topographic (potential) images is approximately 15 pm (10 mV) between the faulted and unfaulted parts using heterodyne AM-KPFM, on the other hand, this difference cannot be observed using AM-KPFM mode. Original of this was attributed to the low crosstalk between the topographic and the LCPD measurements in heterodyne AM-KPFM.
Observation of Ferromagnetic Resonance in Magnetic Exchange Force Microscopy (MExFM)
Authors: Shi Yun Bo , Xue Hui , Ma Zong Min , Zhang Huan , Tang Jun , Xue Chen Yang , Liu Jun , Li Yan Jun
Published: April 2014

The atomic spin interaction is very important for understanding the superficially magnetic feature of nanostructure at atomic level. Magnetic exchange force microscopy (MExFM) is an innovative means of measuring surface spin force. But it is difficult to separate the surface topography and spin information. We develop the magnetic exchange force microscopy using ferromagnetic resonance (FMR-MExFM). The theoretical and experimental results demonstrate that this method can separate the two kinds of information effectively. Here, in order to obtain the high sensitivity in detecting the ferromagnetic resonance, we fabricate the microwave irradiation device to optimize the position between the device and the cantilever. We have succeeded in observing the ferromagnetic resonance effect and determining its resonant frequency using the homemade microwave irradiation device and the network analyzer. This research is very important for developing FMR-MExFM and novel magnetic sensor, detecting the magnetic information, etc.
Visible Light Photocatalytic Degradation of Methylene Blue over N-Doped TiO2
Authors: Hu Yu Long , Zhou Li Qing , Liu Hong Fang , Guo Xing Peng
Published: April 2014

The visible light photocatalytic degradation of methylene blue (MB) over N-doped TiO2 (N-TiO2) was investigated. The intermediate products of MB in the photocatalytic degradation process were analyzed by HPLC-MS technique. The results show that the cleavages of CS+=C and CN=C functional group in the central aromatic ring and the cleavage of N-C bond between the methyl group and nitrogen atom all can occur in the visible light photocatalytic degradation process over N-TiO2, but MB is difficult to be mineralized completely to the inorganic products. A detailed degradation pathway of MB has been proposed on the basis of a careful identification of intermediate products.
Power Handling Capability Improvement of Metal-Contact RF MEMS Switches by Optimized Array Configuration Design of Contact Dimples
Authors: Zhao Chen Xu , Guo Xin , Deng Tao , Li Ling , Liu Ze Wen
Published: April 2014

This paper presents a novel approach to enhancing power-handling capability of metal-contact radio-frequency micro-electro-mechanical systems (RF MEMS) switches based on an Optimized Array Configured (OAC) contact dimples design. The simulation results reveal that this strategy can distribute the RF current more uniformly through each contact of the switch than traditional multiple parallel-configured contacts design, thus leading to a more effective reduction of current through each contact. Therefore, probability of micromelding and adhesion at metal contact point owing to localized high current induced Joule heating, which limits the power handling capability of the metal-contact RF MEMS switch, can be effectively reduced by the proposed approach. Comparing with previously fabricated switch, power-handling capability of the switch with OAC contact dimples can be dramatically improved over 390%.
Voltage Reversal of Microbial Fuel Cells Stacked in Serial
Authors: Huang Rong Hai , Mo Bing , Zhao Feng , Ling Chao Dong
Published: April 2014

Microbial fuel cells (MFCs) are regarded as a promising and environmental friendly method for wastewater treatment and bio-production. The output power of a single cell is inadequate to drive loads directly. Microbial fuel cells stacked in serials will promote bio-production or bioremediation and the voltage of the MFCs can be scaled up by connecting the cells in serials, whereas voltage reversal may emerge in this case. The causes for reversing polarity of MFCs have received great attention in recent years. This paper designs a power management circuit for microbial fuel cell, studies the mechanisms of voltage reversal and the approaches to solve the problem.
Precise Measurement and Feature Information Extraction of the Key Drag-Reducing Structures of Sharks
Authors: Han Xin
Published: April 2014

The precise measurement and feature information extraction of the biological macroscopic body shapes and surface micro-morphologies is an important precondition to obtain configuration resources directly in research of functionality biomimetics. The sharks with low-resistance body shape and scarfskin were selected as the typical example of creatures simultaneously with functional body shape and surface micro-morphology. Taking a frozen Carcharhinus brachyurous body and a piece of pretreated scarfskin as the biological samples, the measurement and reconstruction of its macroscopic body shape and surface micro-morphology were conducted respectively. The experimental results indicate that the measuring and reconstructing methods adopted can efficiently ensure the facticity and integrity of the measurement results, which contributes to the structure digitalization and feature information extraction of the biological prototypes. The study demonstrated in this paper may provide method references on information collection and data processing for design of bionic functional devices and interfaces.
Evaluation of Annealing Effects on TiO2 Nanorod Arrays for Dye-Sensitized Solar Cells by Equivalent Circuit Analysis
Authors: Sui Mei Rong , Gu Xiu Quan
Published: April 2014

TiO2 nanorod arrays (NRA) were synthesized via a facile hydrothermal method for preparing the dye-sensitized solar cells (DSSC). It was found that a post-thermal treatment facilitated enhancing the cell efficiency. The cells containing NRs underwent 500 °C annealing exhibited much higher efficiency than those un-sintered ones. Further, the internal resistance analysis was carried out to reveal the mechanism underlying the DSSC performance improvement. Specifically, the equivalent circuit model was employed to derivate the internal resistances, which was consistent with the experimental results. It was found that the sintered cells exhibited a higher series resistance and a lower shunt resistance than the un-sintered ones, suggesting the higher photocurrent density might result from the larger amount of dye loading.
Nanotechnologies for Potential Environmental Applications in Groundwater and Soil
Authors: Gao Yuan Yuan , Zhou Qi Xing
Published: April 2014

In recent years, environmental application of nanotechnologies has attracted considerable interests. Nanometer materials have novel physical, chemical and biological properties, which have gain wider application for pollution prevention, detection, monitoring and remediation of pollutants, such as heavy metals, inorganic and organic pollutants. This review summarizes environmental cleanup and provide a background in both laboratory and pilot study. Furthermore, this overview stated the current practice in contaminated soil and groundwater, and future directions for nanoremediation, especially for nanoscale zero-valent iron. The future of nanophytoremediation was also discussed in details.
Study on Preparation and Resistive Switching Characteristics of SnO2 Films
Authors: Li Hong Xia , Chen Hui , Ke Wei Qing , Xi Jun Hua , Kong Zhe , Ji Zhen Guo
Published: April 2014

In this paper, resistance switching devices with Au/SnO2/Al sandwich structure were fabricated. The prepared devices showed a reliable unipolar resistance switching characteristic. The forming voltage of SnO2-based resistance devices increased with increasing film thicknesses, while SnO2film thickness had little influence on set and reset voltages. When the SnO2film thickness was 46 nm, the device showed steady and reliable conversion under voltage sweeping and the ratio between high and low resistance states was higher than 102, which can basically satisfy the requirements for practical application.
Effect of Milling Time on Properties of Ti-48at%Al Composite Powder Prepared by High Energy Milling
Authors: Yi Feng , Cai Xiao Lan , Zhou Lei , Yu Ming Jun , Li Zheng , Jiang Qing Wei
Published: April 2014

The Ti-48at%Al composite powder was synthesized by high energy ball milling. The properties of the composite particles, such as medium diameter,Phase ,microstructure and components, were respectively investigated . Results show that, the phase evolution process can be described by: Ti+ Al fcc Ti (Al),TiAl,TiAl3,Ti3AlTiAl3,Ti3Alamorphous phase. After milling 3 hours, Fcc Ti (Al) solid solution, TiAl, TiAl3, Ti3Al were found. After milling 9 hours, the amorphous phase of Ti - 48 at % Al were produced. The element distribution of the mechanically alloyed Ti-48at%Al powder was close to the initial design composition after 5 h milling, but this distribution was inhomogeneous. Medium diameter (D50) of Ti-48at%Al composite powder achieved the minimal size 9.56 μm after milling for 5hours.
Preparation and Photocatalytic Properties of Rod-Shaped TiO2 Based on Salix Fiber
Authors: Li Ya Bin , Huang Jin Tian , Pan Yan Fei
Published: April 2014

In the paper, the TiO2nanomaterials adopted the microcrystalline cellulose as the template by the template method and sol-gel method was prepared. Through the infrared spectrometer (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), the surface morphology, composition and the type of the samples were characterized respectively. The influence of the macro morphology of TiO2photocatalytic performance to use the reaction of decolorization and degradation of methyl orange as model was analyzed. The results showed that TiO2which was produced by the template of sallix fiber was Rod-shaped and the average diameter size of nanocomposite structure was 20.592 nm, which can provide a new method of producing other morphology of TiO2.
Deposition and Characterization of Mg Doped CuCrO2 Films by DC Magnetron Sputtering
Authors: Wu Su Zhen , Deng Zan Hong , Dong Wei Wei , Shao Jing Zhen , Fang Xiao Dong
Published: April 2014

Single-phase delafossite type Mg-doped copper-chromium oxide thin films were prepared on c-sapphire, quartz glass and n-Si substrates by direct current (DC) magnetron sputtering using a CuCr0.97Mg0.03O2 (CCMO) ceramic target, followed by post annealing at 800 °C in a nitrogen atmosphere. X-ray diffraction (XRD) revealed that the film deposited on c-plane sapphire was highly c-axis oriented, while the films on quartz glass and Si only showed weak (0 1 2) peak. The transparencies of the films on c-sapphire and quartz glass were over 60 % in the visible light region and the direct bandgap of both films were estimated to be 3.16 eV. The in-plane resistivities were 0.24 Ωcm and 7.68 Ωcm for the crystallized films on c-sapphire and quartz glass, respectively. The electrical property of the formed CCMO/n-Si junction was found to be rectifying with a ratio of ~15 at ±2 V.
Nanomechanical Properties and Surface Wettability of Carbon Films Prepared by Magnetron Sputtering
Authors: An Wei Wei , Zhao Xiao Li , Gu Le , Su Run Zhou
Published: April 2014

In this work, carbon films were deposited by magnetron sputtering on silicon substrate. The effect of sputtering time on the surface wettability and mechanical properties of carbon films was investigated. Contact angle measurement was used to analyse surface wettability, and the nanomechanical properties were characterized by nanoindentation. In experiments, the sputtering time was 45 min, 60 min, 75 min and 90 min. The measurement results show that the maximum film hardness was achieved for sputtering time 90 min, with a value of 2.34 GPa. Longer sputtering time resulted in preferable mechanical properties. It was analyzed that the size of the crystal grains on the substrate surface and thickness of the films were increased with the increment of sputtering time. The surface roughness decreased with the increase of sputtering time. Moreover, Youngs modulus increased with sputtering time and the maximum value was 16.94 GPa. The contact angle measurement results show that the prepared films take on the hydrophilicity. The minimum contact angle was achieved for sputtering time 45 min with a value of 54o.
Preparation of Alumina Nanowires by Etched Method in Acid Solution
Authors: Yang Rui , Jiang Gui Quan , Ma Jun , Han Shi Yan , Pang Jiu Yin
Published: April 2014

Porous alumina films are obtained on aluminum piece by electrochemical method. In this work, we ues a kind of method for alumina nanowires by the alumina films. The result is showed with SEM. We study the effects of etching action in the dilute HF solution, and deduce the reason. We study catalyzed formaldehyde by the alumina nanowire supported titanium dioxide, results show that, the catalytic effect is better than activated carbon supported.
Preparation of TiO2 (Au) Nanotubes by Hydrothermal Method for Photocatalytic Reduction of Cd2+ Ions
Authors: Feng Chun Xiao , Xu Guang Qing , Lv Jun , Zheng Zhi Xiang , Wu Yu Cheng
Published: April 2014

Highly dispersed TiO2 nanotubes (TiO2-NTs) were synthesized via the reaction of anatase TiO2 powder with NaOH solution. Au nanoparticles of about 5 nm were deposited on the surface of TiO2-NTs with hydrothermal reduction method. The prepared nanocomposites were well characterized with TEM and XRD. Their photocatalytic properties and reducing ability were investigated by UV-Vis absorption and photocatalytic reduction of Cd2+ ions with different amount of TiO2-NTs and TiO2-NTs (Au) varying from 0.1g to 0.001g. The results from absorption patterns and AAS showed that the absorption intensity of TiO2-NTs (Au) was higher compared with that of TiO2-NTs. Moreover, the concentration of remanent Cd2+ (0.48mg/L) using TiO2-NTs (Au) was lower than that of Cd2+ (0.65mg/L) using TiO2-NTs.
Molecular Dynamics Simulation of ZnO Nanowire Manipulation
Authors: Li Dong Jie , Zhang Li , Song Jian
Published: April 2014

In order to achieve a better manipulation performance of ZnO nanowire, the ZnO nanowire forces are analysed, and molecular dynamics simulations are conducted. Force model of ZnO nanowire is established to interprete the drifting, bending and fracturing conditions in ZnO nanowire transfer experiment. As ZnO nanowire force is too complex to build a precise mathematical model, molecular dynamics is proposed to simulate the process. Based on the analysis of ZnO nanostructure, the probe-nanowire-substrate model is established. Through changing the operation path of the probe and operation area between the probe and nanowire, simulation results are got. By the Analysis and comparison of simulation results, the optimal operation path and operation area are obtained.
Cell Immobilization and Detection Using Surface Plasmon Resonance Biochemical Analysis System Based on Nano SiO2 Film
Authors: Chen Xing , Zhang Lu Lu , Sun Jian Hai , Li Hui , Cui Da Fu
Published: April 2014

Surface plasmon resonance (SPR) biochemical analysis system began to be developed from the detection and analysis of molecular interactions to the ligand/cell interactions, cell/cell contacts, or cellular reactions. Cells needed be immobilized on the SPR chips based on the penetration depth of surface plasma waves. However it is not easily to fix suspension cells on the bare gold chips. In this paper, an effective method has been developed to immobilize yeast cells on the SPR chip based on a nanoSiO2 film which was chemically modified. The sensitivity of the SPR chip with a nanoSiO2 film is 6×10-7 refractive index unit (RIU), which could meet different applications including cell detection. The whole procedure of cell immobilization has been measured in a lab-free and real-time mode by using our home-made SPR instrument. From the experimental results, the change of the SPR signal of the SPR chip with a modified nanoSiO2 film is 2.83 times of the bare SPR chip. That means the cell immobilization capability of the modified SiO2-coating SPR chip is much stronger than that of the bare gold SPR chip, which was also proved by using a microscope. Yeast cells can be effectively fixed on the SPR chip and their immobilization process could be monitored, which hold great potential for the immobilization, detection and further analysis of other suspension cells, such as blood cells.
Embedded Seal Cavity Fabricated in HTCC MEMS Technology
Authors: Li Chen , Tan Qiu Lin , Xiong Ji Jun , Zhang Wen Dong , Ren Zhong , Yang Ming Liang , Luo Tao
Published: April 2014

This article presents a design and fabrication method of a embedded cavity using alumina casting-belt. This method is based on HTCC (high-temperature co-fired ceramic) MEMS technology with using fugitive materials. The test structures are fabricated using two different fugitive materialsPolyimide film and ESL4900 film and two different lamination pressures (15MPa and 21MPa). The final stack was sintered by selecting different temperature process parameters in the high-temperature sintering process. Complete the analysis of the sample cavity structure using a SEM (scanning electron microscope). The manufacturing method is available for structural integrity and good air tightness of ceramics sealed cavity and it will be applied to the fabrication of flow sensors, capacitance pressure sensors etc.
Fracture Behavior of Cu/Cu–WCP Layered Composites
Authors: Yan Feng , Guo Rong Xin , Xia Hai Ting , Yu Hai , Zhang Yu Bo
Published: April 2014

In order to understand the fracture mechanisms of Cu/CuWCP layered composites. An in-situ experimental study was carried out to investigate the behavior of the composites under uniaxial tensile loading. The specimens were manufactured by vacuum hot-pressed sintering technique, microscopic observations displayed that the microstructure of Cu/CuWCP layered composites distribute uniformly, and have no visible defect at interface. In situ tensile tests were performed in a scanning electron microscope (SEM) and the tensile strengths, failure modes of composites were measured. From the in situ experiments, the stages of nucleation, growth and coalescence of cracks in the vicinity of particles are well observed and understood. The results indicated that microcrack initiation happens at particle agglomeration and the matrix-particle interface because bond strength is weak,. With the density of microcracks increaseing, macrocrack formed, and finally cause failure of CuWCP layer, however, the Cu layer is not fracture during the whole testing.
Experimental Research on Influence of Temperature and Compression on Wrinkle Evolution of Thin Films on Compliant Substrates
Authors: Zhao Xiao Li , Zhang Sui Xing , An Wei Wei , Yu Hai Chao , Liu Zhan Shan
Published: April 2014

Wrinkle evolution under temperature and compression was experimentally explored in a metal film deposited on a compliant polymer. After wrinkle formation, the samples undergo thermal annealing in different temperature circumstances. In the range of 75-150°C, the wavelength and amplitude of wrinkles became both smaller as the temperature increased, indicating that annealing effectively releases residual stress and promote material modification. In contrast, compression only changed wrinkle rearrangement, and did not alter the wavelength and amplitude. These results suggest that external stimulation can transform wrinkled surfaces. This work provides the guidance for service conditions of surface wrinkling.
Experimental Investigation and Numerical Simulation of Pure Copper Foil Springback in Micro-Bending Process
Authors: Lin Xiao Juan , Wang Guang Chun , Jiang Hua , Li Jin
Published: April 2014

Springback is an important factor influencing forming precision in bending process, which becomes more complex for micro metal foil due to the size effect existing. Bending springback is studied through the micro bending experiments designed with different grain sizes and foil thicknesses using T2 purple copper in this paper. The accurate stress-strain relationships are obtained based on the copper foil tensile experiments; the bending process of micro-component is simulated based on both dynamic explicit and static implicit codes. Comparison of simulation results with experimental results shows that: thickness can serve as an important parameter effecting on the springback; the trend of springback amount rising with a thickness diminishing enhances in small size; sheets with same thickness exhibit phenomenon of springback angle reducing with an increasing grain size. Bending springback of micro metal foil indicates obvious size effect on foil thickness and grain size.
Research on the Characterization of Ultra-Smooth K9 Glass Surface Polished by Nanoparticle Colloid Jet Machining
Authors: Song Xiao Zong , Zhang Fei Hu
Published: April 2014

In this work, optical K9 glass surface has been flattened by nanoparticle colloid jet machining, which is an ultra-smooth surface processing technique utilizing surface chemical effect between work surface atoms and nanoparticles in alkaline colloid to remove the uppermost surface atoms. The surface removal process of nanoparticle colloid jet machining has been investigated through K9 glass polish experiments. And the characterizations of ultra-smooth K9 glass surface polished by nanoparticle colloid jet machining have also been studied in this paper. Surface profiler and atomic force microscopy (AFM) are used to observe the surface microscopic morphological characteristics of K9 glass sample before and after polishing by nanoparticle colloid jet machining. The measurement results of processed surface prove that the primary scratches on the original surface have been completely wiped off by nanoparticle colloid jet machining and the roughness of the K9 glass surface has been improved to be less than 1 nm (Rq). Autocovariance (ACF) is investigated along a cross section of the K9 glass surface to determine the dominant spatial frequencies. The ACF curves show that the surface morphology of K9 glass processed by nanoparticle colloid jet machining is completely different from the preprocessed surface. The final K9 glass surface has been flattened by nanoparticle colloid jet machining. The microscopic morphological profile of the final K9 glass surface becomes increasingly smooth and eventually close to a flat state.
Fabrication and Characterization of Transparent ZnO Film Based Resistive Switching Devices
Authors: Li Hong Xia , Shen Dong Dong , Ke Wei Qing , Xi Jun Hua , Kong Zhe , Ji Zhen Guo
Published: April 2014

In this paper, ZnO thin films were prepared on ITO conductive glass by direct current magnetron sputtering and the Cu electrodes were evaporated on ZnO/ITO by electric beam evaporation to get transparent Cu/ZnO/ITO resistive random access memory. The crystal structure and surface morphology were investigated by X-ray diffraction and atomic force microscopy, respectively. The transmittance spectra of ZnO/ITO in the visible region were measured by UV-VIS spectroscopy. The resistive switching characteristics of the fabricated devices were investigated by the voltage sweeping method, which showed that the transparent Cu/ZnO/ITO device had good resistive switching characteristics.
Multilayer Microfluidic Electrokinetic Device with Vertical Embedded Electrodes
Authors: Zhang He , Liu Xiao Wei , Tian Li , Han Xiao Wei , Liu Shang Yu
Published: April 2014

In this paper, we fabricated a novel multilayer microfluidic device with vertical embedded electrodes. The device was composed of printed circuit board (PCB) substrate with vertical embedded electrodes, the polyimide insulating layer and the polymethyl methacrylate (PMMA) with micro structures. The vertical electrodes were made by metal wire and integrated on the PCB substrate, they can be replaced when fail or broken. In addition, we investigated the relationship between electrodes height and the electro-osmotic flow by using numerical simulation. The results show that, with the increase electrodes height inside the microchannel, the speed of electro-osmotic flow increased and concentration field distribution improved significantly.
Research of Magnetic Fluid under the Orthogonal Stationary Magnetic Field
Authors: Zhao Meng , Yi Li Na , Jiang Shan Lin , Liu Cheng Jun
Published: April 2014

The nonlinear characteristic is the one of essential characteristics about the magnetic fluid. The orthogonal stationary magnetic field is caused by the mutual orthogonal DC. According to the grads of magnetic field in the area filled with magnetic fluid, the magnetic density of magnetic fluid changes with the grads of magnetic field. With the increasing magnitude of DC, the magnetic density of magnetic fluid can be increased. Error of the measured voltage wll be increased as the volume of the changing rate of DC increasing.
Numerical Simulation of Jetting Instability in Flow Focusing Microfluidics
Authors: Zhang Hong Bo , Liu Jian Pu , Lai Huan Xin
Published: April 2014

In this paper, jetting behavior of two immiscible liquids, water as the outer liquid and silicone oil as the inner liquid in typical flow focusing microchannels were numerically studied using VOF method. At low capillary number, uniform microdroplets were obtained by the absolute instability. With the increasing of fluid flow ratio, the jet is thinner and tends to break up further away the cross junction. The results showed that the flow rate ratio is the main factor that influences the microdroplet sizes, while the frequency of microdroplets formation can be controlled mainly by the surface tension when it is in the jetting regime.
Swirl-Based Non-Contact Method of Cell Orientation Control
Authors: Huang Wei Jun , Zhang Qin
Published: April 2014

Orientation adjustment is an important issue in the micromanipulation of cells. A non-contact method based on a swirl for cell orientation control was introduced in this paper. The swirl is produced by a pair of opposite micro-fluids squirting from two parallel tubes. Cell orientation adjustment is realized by cells rotation due to swirl viscous drag, which drives cells to desired configurations. The appropriate distances between the end face of the two tubes and the distance between the axes of them are 1-3 times tube diameter for the cells rotating in the swirl central zone. Especially when the distances are kept double the cell diameter, cells rotate steadily round the swirl central point. By pulsating jetting, fluctuant micro-fluid are generated which make cell rotating a certain angle. Adjusting the pulse duration, pressure and jetting velocity, the cell rotation angle can be controlled which make orientation control more precisely. The method is valid for cells of different shapes and sizes. The effectiveness of the proposed non-contact method for cell configuration control was verified by experiments.
Preparation and Thermosensitivity of N-Isopropylacrylamide Microgels Containing L-Phenylalanine
Authors: Chen Jiao Jiao , Fu Xin Lei , Shi Dong Xin
Published: April 2014

Novel chiral temperature-sensitive microgels based on N-isopropylacrylamide are reported in this paper. Such particles, poly (N-isopropylacrylamide-co-acrylic acid-L-phenylalanine ethyl ester)[ poly (NIPAM-co-ALPhe)], were prepared by free radical polymerization of NIPAM, chiral monomer ALPhe and crosslinker N,N,-methylene-bis (acrylamide). The microgels exhibit spherical shape and favorable monodispersity. Increasing the content of ALPhe units incorporated into the microgel network will increase the average diameter, but decrease the swelling ratios and the transition temperature of particles.
Design and Fabrication of Universal Inertial Switch Based on MEMS Technology
Authors: Liu Shuang Jie , Hao Yong Ping , Liu Feng Li
Published: April 2014

Aiming at such defects as the widely distributed threshold and poor universal performance in traditional inertial switch, a MEMS universal inertial switch was designed. The switch consisted of two annular lectrodes, each electrode was suspended by four serpentine flexures and could move freely. There was a gap between the two electrodes and the gap kept the swtich open during non-working state . When the absolute value of acceleration along a particular direction in the x-y plane exceeded a certain threshold value, one of the electrode (the sensing mass) contacted with the other electrode, the ON-state was held and the duration of the ON-state extended because of the flexible distortion of serpentine flexures . The finite element dynamic model was established and simulated in LS-DYNA and the simulation results showed that under the effect of 800g acceleration, the response time and the contact time of the switch were approximately 0.135ms and 20respectively. Compared with other inertial switch, the designed switch exhibited the higher trigger sensitivity and contact reliability. The micro inertial switch was fabricated using the MEMS bulk micromachining process, including the crucial technology of KOH etching, ICP etching spray coating method and so on. The testing system was designed and the shock testing was selected to test the performance of the switch. The test results showed that when the acceleration reached 800g, about 83% switches could work normally.
Preparation and Characterization of Nanofibriled Cellulose via High Frequency Ultrasonication from Cornstalk
Authors: Lu Yun , Sun Qing Feng , Li Jian , Liu Yi Xing
Published: April 2014

To obtain nanofibriled cellulose (NFC) with uniform diameter and high aspect ratio, chemical pretreatment was employer to remove the hemicellulose and lignin of cornstalks with further ultrasonic treatment. The prepared samples were characterized by SEM, TEM, FTIR, XRD, and TG. Results showed: The obtained NFC possessed the uniform diameter of about 25 nm and high aspect ratio (>300). The crystalline type of NFC was cellulose I type. The NFC with high crystallinity, high aspect ratio, and nanoscale is a newly great potential nanomaterial in different fields.
Architectural Design and Simulation of a Fourth-Order Sigma-Delta Modulator
Authors: Fan Wen Jie , Lv Qiu Ye , He Chong , Yin Liang , Liu Xiao Wei
Published: April 2014

Sigma-delta ADC outperforms the Nyquist ADC in precision and robustness by using oversampling and noise shaping. A fourth-order sigma-delta modulator of input feedforward architecture is designed and simulated in system-level. Input feedforward architecture has advantages of low output swing of integrators and simple structure. Proper circuit parameters are also presented in this paper. The simulation revealed that the modulator achieves 109 dB dynamic range in a signal bandwidth of 1 KHz with a sampling frequency of 250 KHz.
Interaction Effects of Micronozzle Geometric Parameters on Propulsion Performance
Authors: Li Xiao Ping , Yuan Wei Zheng , Shen Qiang , Xie Jian Bing , Chang Hong Long
Published: April 2014

This paper reports an effective design method for optimizing the geometric parameters of a micronozzle. Numerical analysis is conducted to predict the propulsion performance of micronozzles. By means of design of experiment (DOE), the number of numerical experiments is reduced dramatically from 1024 to 16. The interaction effects of the geometric parameters are taken into consideration for the first time. The results indicate that the interaction effects of geometric parameters cannot be neglected in choosing the optimal parameters for a practical design.
Ultra-Precision Machining of Off-Axis Convex Ellipsoidal Surface Using Two Different Accurate Spiral Tool Paths
Authors: Ji Shi Jun , Yu Hui Juan , Zhao Ji
Published: April 2014

The off-axis parabolic mirror plays more and more important role in high-tech areas since the advantages of reducing space and improving the quality of imaging. Two ultra-precision manufacturing methods are often applied to machining the off-axis ellipsoidal mirror, which one is revolving the cylindrical blank around the axis of ellipsoidal surface and another one is revolving around the axis of cylindrical surface. But which machining method can produce a better result has no rounded comparisons and analysis according to previous research. In this paper, the tool path generation method is presented and the corresponding tool paths of each manufacturing method for the off-axis ellipsoidal mirror are calculated respectively. The motion characteristics are also analyzed and compared correspondingly. Finally, the effects of diamond tool parameters are further analyzed in theory to avoid the tool interference. The studies processed in this paper provide a theoretical basis of choosing the ultra-precision manufacturing method for the off-axis ellipsoidal mirror and can improve the efficiency and precision of processing.
Graphitization Wear of Diamond Tool in Nanometric Cutting of Single Crystal Silicon
Authors: Wang Jia Chun , Xin Ming Ming , Cao Si Yu , Zhao Teng
Published: April 2014

During ultra-precision cutting of brittle materials, the wear of diamond tool seriously affects the quality of machined surface. By molecular dynamics modeling of nanometric cutting, the generation of graphitization and its formation process at the cutting edge of tool are observed. By analyzing the process, the reason of the graphitization wear is mainly thermo-chemical reactions. By calculating the changes of coordination numbers of the tool atoms, graphitization conversion rate keeps increasing along the cutting process but gets stable after a certain length, which indicates the graphitization wear will occur in the same process.
Polarization-Insensitive Holey Fiber with Ultra-Small Mode Areas Using a Cross-Slot-Structure Core
Authors: Wang Guan Jun , Wang Zhi Bin , Chen You Hua , Chen Yuan Yuan , An Yong Quan , Li Shi Wei , Zhang Min Juan , Li Jin Hua
Published: April 2014

A high nonlinear, dispersion flattened hybrid nanofiber with a silicon/silica cross-slot-structure nanocore is firstly proposed and analyzed, which is insensitive to polarization for implementing quasi-TE and quasi-TM fundamental modes transmission due to cross slot effect. Simulation results show that fundamental mode of ultra-small mode effective areas and high nonlinearity at TE and TM polarizations, which are confined in the narrow cross slot by four silicon ribs, can be achieved via this cross sot structure core. Moreover, the cladding of four large-air-holes promotes tailoring the group velocity dispersion (GVD) and enhancing nonlinearity furthermore. Our results indicate that ultra-small Aeff of 0.098μm2 and flat anomalous GVD with less than 13.5 ps.km-1.nm-1 dispersion ripple at C-band are realizable.
Influence on Friction Material Performance of Nano-MMT Composites of PF by In Situ Method
Authors: Nie Hua Wei , Zhou Yuan Kang , Yang Lv , Cao Yang
Published: April 2014

Mass fraction of 1.5%, 3% of the nanomontmorillonite (MMT) were separately added in the phenol prepolymer, phenolic resin/ MMT was synthesized by in-situ method (it is called PF/M). The PF/M was carried out TG analysis using thermal analyser, and the synthetic resin PF/M were as new resin matrix to prepare semimetallic friction material, tribological performance test was carried on XD-MSM fixed speed type friction-wear testing machine in accordance with the GB_5763-2008. The results show that the heat resistance of composite PF/M and tribological performance of friction material are best when nanoMMT is 3% in the resin, the Carbon residue rate of PF/M is an increase of 37% compared with PF without nanoparticles at 600°C, thermal recession temperature of sample by the preparation of PF/M increases above 100°C, and it has stable friction coefficient, overall wear rate decreases 26%, especially in high temperature stage at 350°C, the wear rate decreases significantly, its wear rate decreases 30%.