bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat Transfer Characteristic of Flat Trapezoid Grooved Micro Heat Pipes
Authors: Yang Yan Xia , Wang Xiao Dong , Luo Yi , Zou Liang Liang
Published: April 2014

To study the heat transfer performance of micro heat pipe, theoretical analysis of flat plate micro heat pipe with trapezoid cross section are presented in this paper. A one-dimensional stationary mathematical model for micro heat pipe grooved capillary flow using finite volume method (FVM) was established. The micro heat pipe had vapor space connect with each other and the influences of shear stress between vapor and fluid in the working process were described in the model which made the model more precisely. The axial variation of working fluid distribution in the heat pipe, pressure difference between vapor and liquid, and velocity of vapor and liquid were analyzed. In addition, the maximum heat transport capacity of micro heat pipe was calculated. The simulation results showed good agreement with the experiment results, and it could predict the heat transfer performance accurately, which was useful to micro heat pipe structural design.
Graphene Synthesis on Specified Location
Authors: Zhang Han , Zhao Chen Xu , Guo Xin , Lu Yan Wu , Liu Ze Wen
Published: April 2014

The synthesis of graphene using chemical vapor deposition (CVD) on patterned Cu thin films was studied. A series of experiments were carried out to optimize the CVD process of graphene synthesis on Cu thin films and the optimal growth conditions were obtained. Consequently, few-layer graphene which had been characterized by optical microscopy and Raman spectroscopy atomic was synthesized. Conductive atomic force microscopy (AFM) was used to measure the conductivity of metal-graphene contact samples and the result showed that the conductivity of CVD synthesized graphene on Cu thin films is higher than the transferred graphene on same Cu thin films, which was synthesized on 25 μm Cu foils by conventional CVD method.
Experimental Investigations of the Detonation Synthesis of Micron Al2O3 by the Precursor of Thermal Decomposition
Authors: Li R.Y. , Yang H.L. , Yan H.H. , Wang X.H. , Li X.J.
Published: April 2014

The Al2O3 is synthesized by detonation of mixed explosive, prepared by mixing RDX and aluminum hydroxide named as precursor of thermal decomposition. The production of detonation is analysed by XRD, TEM and DTA/TG. The curve of XRD indicates that the production are (α+γ)-Al2O3. The average crystal size of Al2O3 is 126nm calculated by the Scherrer equation. The photographs of TEM show that all granules of Al2O3 are spherical, and the average size of granule is 1000nm. The visible exothermic or endothermic peak does not appear on the curve of DTA from 50 to 1300 degree Centigrade. The curve of TG indicates that the production of detonation generates 12% weight loss from 50 to 1300 degree Centigrade.
“Double Junction” of Ag-Doping TiO2 Nanotubes
Authors: Li Jing Ling , Cao Xiao Xia , Yu Hua Liang , Gan Yong Jiang
Published: April 2014

Ag-doping TiO2 nanotubes (Ag-TNTs) were synthesized. A double junction is proposed, involving a Schottky junction and p-n junction (denoted as Ag-p-n junction) occurring between the Ag particles and the nanotube surface, as well as forming inside TiO2 nanotubes, respectively. The strongly built-in electric field of the junctions promotes the separation of photo-holes and photoelectrons, enhancing the photocatalytic efficiency. Ag-TNTs were characterized by XRD and TEM. XRD results indicated that a mixture of anatase and rutile phases. The presence of a new peak at 271 cm1 was revealed by Raman spectral analysis of Ag-TNTs.
The Effective Thermal Conductivity of Porous Polymethacrylimide Foams
Authors: Yue Peng , Qiu Lin , Zheng Xing Hua , Tang Da Wei
Published: April 2014

A freestanding sensor-based 3ω method was employed to measure the effective thermal conductivity of porous polymethacrylimide (PMI) foams with different densities at different temperatures. Experimental data showed that within the measuring temperature range, the effective thermal conductivity increased with temperature. Moreover, the formation mechanism of the relationship between the effective thermal conductivity and temperature was analyzed in this paper.
Experimental Investigation of Microstructure and Piezoresistive Properties of Phosphorus-Doped Hydrogenated Nanocrystalline Silicon Thin Films Prepared by PECVD
Authors: Pan Hai Bin , Ding Jian Ning , Cheng Guang Gui , Cao Bao Guo
Published: April 2014

This paper presents an experimental investigation of microstructure and piezoresistive properties of phosphorus-doped hydrogenated nanocrystalline silicon (nc-Si:H) thin films. The phosphorus-doped nc-Si:H thin films (5% doping ratio of PH3 to SiH4) were deposited by plasma enhanced chemical vapor deposition (PECVD) technique. The microstructure and surface morphology of the deposited thin films was characterized and analyzed with Raman spectroscopy and atomic force microscopy (AFM), respectively. The piezoresistive properties of the deposited thin films were investigated with a designed four-point bending-based evaluation system. In addition, the influence of temperature on the piezoresistive properties of these thin films was evaluated with the temperature coefficient of resistance (TCR) measurements from room temperature up to 80°C. The experimental results show that phosphorus-doped nc-Si:H thin films prepared by PECVD technique are a two-phase material that constitutes of nanocrystalline silicon and amorphous silicon, and they present a granular structure composed of homogeneously scattered nanoclusters formed by nanocrystalline silicon grains (6nm). Moreover, phosphorus-doped nc-Si:H thin films exhibit negative GF at room temperature and show good thermal stability from room temperature up to 80°C, and the value of GF and TCR is about-31 and-509ppm/°C, respectively. These features could make phosphorus-doped nc-Si:H thin films act as a promising material for piezoresistive-based MEMS sensor.
Research on Graphene Preparation by Liquid Phase Ultrasonic Exfoliation and Antifriction Performance in Water
Authors: Zhao Hai Chao , Qiao Yu Lin , Zang Yan
Published: April 2014

The different layers of graphene were prepared by liquid ultrasonic direct exfoliation. The dispersion stability of graphene in water under different ultrasonic time, the antifriction Performance, and the elements and morphology of the wear surface are investigated. The wear mechanism of graphene solution was preliminarily discussed. The results indicate that graphene with thickness of 10nm-150nm can be produced by ultrasonic peeling expanded graphite and the dispersion stability of graphene aqueous is best when sonicating for 3h. The antifriction property and wear mechanism of graphene aqueous vary with the graphene content. When graphene content is 0.01wt%, the antifriction performance of graphene aqueous was optimum and its wear mechanism was abrasive wear.
Tribological Properties of Nano-MMT/In Lubricant Additive on 45#Steel Tribo-Pair
Authors: Cao Yang , Zhou Yuan Kang , Yang Tao Yue , Zhang Da Bin , Yang Lv
Published: April 2014

1:1 MMT/In composite nanopowders were prepared by nanoMMT and nanoIn modified with coupling agent KH550, and the nano-MMT/In lubricating oil dispersion system was prepared by 150N base opl containing 3 mass fraction of nano-MMT/In composite powders, and then took the dispersion effect by laser particle size analyzer ,TEM and IR. The anti-wear and friction-reducing behaviors of that lubricating oil dispersion system were observed on the MMU-10G abrasive-wear tester with 45#steel tribo-pair, the morphology and the element of the worn surfaces were analyzed by SEM and EDX. The results showed that the grain size of the modified nano-MMT/In was smaller than the one without modification, and the modified nano-MMT/In had the good dispersion in the system; compare with the one in base oil system, the average friction coefficient of sample of 45#steel tribo-pair in nano-MMT/In additive lubricating oil system had declined by 27.5%, and the total wear mass loss had declined by 63%; The surface of sample after friction had created the self-repairing film that contain the characteristic element of MMT and In, that phenomenon was caused by the interaction of nano-MMT and nano-In.
Improved Study on the Performance of Polyacrylamide/Attapulgite Clay Composite Material Removing Copper (II) Ions from Aqueous Solution
Authors: Li Chun Lei , Xu Hui , Zhang Jun Long , Wang Wei , Tang Jing , Wu Jun Xia
Published: April 2014

A removal of Cu (II) ions from aqueous solutions onto PAM/ATP has been investigated using batch adsorption technique, including the effect of pH, contact time, initial metal ion concentration, adsorption thermodynamics and kinetics. PAM/ATP was characterized with Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The equilibrium data were analyzed using Langmuir and Freundlich isotherms and the best interpretation was given by Langmuir. The maximum adsorption capacity was found to be 212 mg/g after 60 min when pH =3. Regeneration experiments showed that the investigated PAM/ATP could be reused without significant adsorption losses even after five adsorption-desorption cycles.
Study on the Improvement of Microprism Retroreflective Material
Authors: Zhu Wen Kun , Zhu Min , Yuan Chang Ying , Diao Rui Min
Published: April 2014

In this paper, the microprism reflective structure is optimized by theoretical research and simulation calculations, and based on the current technology of V-shaped diamond blade manufacturing mode, an improved microprism retroreflective material is designed. By adjusting the intensity distribution and angle of the light cone, we can control the style of light cone which is formed by the reflected light for optimal reflective effect. The microprism reflective structure contains the positive unit and negative unit. The negative unit relative to the positive unit is rotated 60° for producing phase superposition to reduce the non-uniform of the material orientation. Cutting along a straight line by V-shaped diamond blade, the technology creates a plurality of higher-precision and smaller reflective elements and enhances the retroreflective performance. Meanwhile, the overall processing technology which reduces labor force greatly is beneficial to the cost control and highly practical during the fabrication process.
Keywords: microprism retroreflective material, improvement and optimization
Microstructure and Millimeter-Wave Attenuation Performance of Exfoliated Graphite with Different Expanding Volume
Authors: Zhao Ji Jin , Li Xiao Xia , Guo Yu Xiang , Ma De Yue , Yang Li
Published: April 2014

Exfoliated graphite with different expanding volume (EV) was prepared by two-step intercalation, in which the mixture of nitric acid and phosphoric acid, and that of nitric acid and acetic acid were employed as intercalating agent step by step, and potassium permanganate was used as oxidant. Its microstructure was analyzed by scanning electron microscope, and its millimeter-wave attenuation performance was measured by a static method. The results show that the exfoliated graphite forms more microcellular structures and its layers become thinner with the increasing of EV, the interlayers are fully opened and there are more tiny graphite flakes with size distribution between several microns and several ten microns. The millimeter-wave attenuation performance enhances with the increasing of EV, and the 3mm wave attenuation value rises from 5.7dB to 8.68dB When EV increases from 233ml/g to 450ml/g, which is mainly attributed to the full expansion of exfoliated graphite to form larger scattering cross section and the absorption of more tiny graphite flakes with size distribution between several microns and several ten microns.
Photocatalytic Degradation of Diesel Pollutants in Seawater by Using Nano Li-Doped Zinc Oxide under Visible Light
Authors: Yu Xiao Cai , Hu Dong Dong , Chen Jin Fang , Wu Yu Ying , Zheng Xu
Published: April 2014

Zinc Oxide (ZnO) is a potential semiconductor as photocatalyst. Nevertheless, its main absorbance wavelength is in the range of UV light, which consist only a small proportion of solar. In order to utilizing the large proportion of solar light, pure ZnO and Li-doped ZnO nanoparticles with different Li loading (1.0, 2.0, 3.0 and 4.0 at%) and various calcination temperature (300, 500, 700, 900°C) were synthesized through a co-precipitation method and characterized by XRD and TEM techniques. The photocatalytic abilities of photocatalysts are evaluated in simulated experiments of removing diesel pollutants in seawater under visible illumination. Six factors, Li loadings, calcination temperature, dosage of photocatalyst, reaction time, diesel initial concentration, and pH value of seawater, were taken into consideration in the process of phtotcatalytic degradation of diesel experiments under visible light. An orthogonal experiment was implemented to investigate the best combination of five factors (the factor of reaction time was excluded) which can lead to the highest diesel removal rate. The characterization of as-prepared nano-particles showed that Li element was doped into ZnO, and all particles were of hexagonal wurtzite structure. The average crystal sizes of Li-doped ZnO with various calcination temperature (300, 500, 700 and 900°C) are 15.03, 25.97, 48.63 and 55.48nm, respectively, and consequently, higher calcination temperature will contribute to the aggregation of particles. Doping Li appropriately can improve the photocatalystic ability of ZnO under visible light, which can deduce from the single-factor experiments. Calcination temperature is also an evident factor to affect the photocatalytic ability of photocatalyst. The influence order of factors in decreasing order can also be obtain through the orthogonal experiment and the result was as follows: calcination temperature > Li loading ≈ pH value > initial concentration of diesel > photocatalyst dosage. The best combination of the five factors is as follows, the dosage of catalyst 2.5g/L, initial concentration of diesel 1.5g/L, Li loading of catalyst 1.0 at%, calcinations temperature 900oC and pH value 8.25, the removal rate of diesel pollutants in seawater is expected to reach 77.31%.
The Experiment Research of Gas-Assisted Ion Etching Nanograting
Authors: Liu Mei Hua , Feng Di , Li Yan , Yao Bao Yin , Zhong Shuai , Feng Li Shuang
Published: April 2014

By using scanning electron microscope and focused ion beam (SEM-FIB) dual beam system which was self-assembled, with xenon diflouride, nanograting structure has been successfully processed on the gilded silicon wafer. The grating period is 950 nm, and the width of single etched groove is 652 nm. Gas-assisted ion etching is also known as focused ion beam assisted etching (FIBAE). The working principle of FIBAE was analyzed firstly. The different experimental results of nanograting structures which were fabricated by FIBAE and FIB alone were investigated. And the effect of exposure time on nanograting structures was also studied detailed in the FIBAE process. The Results showed that FIBAE has the technology advantage of high reaction rate, saving time, reducing costs, and deep etching, and it provides an effective method for processing nanograting of high depth in the future.
Study of Birefringence and Mode Field for Hollow-Core Photonic Bandgap Fiber
Authors: Feng Li Shuang , Song Wen Shuai , Ren Xiao Yuan
Published: April 2014

Since the Appearance of Hollow-Core Photonic Bandgap Fiber (HC-PBF), it was Widely Concerned for its Excellent Characteristics. in Order to Study the Characteristics of the HC-PBF that can be Used in Resonator Fiber Optic Gyros (R-Fogs), the Model Structure of a Polarization-Maintaining HC-PBF was Built and its Performance was Simulated by Using the Finite Element Method (FEM). its Mode Field Distribution and Birefringence Characteristics were Obtained. the Influences of the Air Core and Cladding Structures on the Mode Field Distribution and Birefringence were Simulated and Analyzed Further. the Result Showed that there are both Core Mode and Surface Mode in the Structure we Built. by Adding Scattering Points into the Fiber Core, the Surface Mode can be Significantly Suppressed. by Matching the Size of Core and Air Holes around the Core, a Birefringence up to 8*10-4 were Obtained.
Effect of Balls/Powder Weight Ratio in Milling on Microstructure and Properties of MWCNTs/Cu Composites
Authors: Yu Ming Jun , Cai Xiao Lan , Zhou Lei , Hu Cui , Li Zheng , Yi Feng
Published: April 2014

High energy milling (HEM) was used to the preparation of multi-walled carbon nanotubes reinforced copper matrix (MWCNTs/Cu) composite powders in this paper. And the MWCNTs/Cu composite material was prepared by the cold-press sintering method. The influence law of balls/powder weight ratio to the MWCNTs/Cu composite powders was discussed. Particle size distribution and fracture micrograph were analyzed by XRD and SEM. The results show that particle size distribution of CNTs/Cu composite powders reached a minimum, when the balls/powder weight ratio was 10: 1. The particle size distribution (D50) of CNTs/Cu composite powders was 22.33μm. The CNTs distributes homogeneously , which is in favor of the mechanical combination of the CNTs and Cu substrate. The tensile strength of CNTs/Cu composite reached 189 MPa.
Vertically Aligned Carbon Nanotubes Transfer with Glass Frit
Authors: He Jie , Zhan Zhan , Du Xiao Hui , Chen Shu Fen , Yu Ling Ke , Zheng Cheng , Wang Ling Yun , Sun Dao Heng
Published: April 2014

Nanogetters, based on carbon nanotubes (CNTs) coated Ti films, do have higher pumping speed and possibly larger sorbed quantity compared with traditional getters, such as St175 of SAES [1]. Although the nanogetter is with the outstanding performance, it is still hard to be integrated into micro electro mechanical systems (MEMS) packaging and devices due to high growth temperature of CNTs (>700°C) [2], poor adhesion with substrate [3, 4], vulnerability to pollute the wafers and difficulty to pattern. Therefore, this paper proposes a promotion of nanogetter based on transferring out vertically aligned CNTs (VA-CNTs) utilizing the glass frit. Compared with the conventional nanogetters, the promotion processes have advantages of (1) compatibility to the MEMS materials with controllable melting temperature and coefficient of thermal expansion (CTE), (2) Enhancement of the adhesion between CNTs and substrate, (3) Avoiding polluting the package wafer during CNTs growth. The results indicate that the promotion processes can be fulfilled by the silicon wafers and have wide applications such as nanogetters, field emission display, etc.
Electromagnetic Induction Heating Bonding between Carbon Nanotubes and Metal Electrode
Authors: Chen Xiao Jia , Chang Di , Lv Qiang , Gan Zhi Yin
Published: April 2014

This paper introduces an electromagnetic induction heating method which is demonstrated to be able to bond carbon nanotubes and metal electrodes. Dielectrophoresis method is taken to realize the parallel directional assembly between carbon nanotubes and metal electrode, and then localized induction heating is adopted to bond them. This technique offers a convenient and reliable way in the practical applications of carbon nanotube interconnection. The bonding principle and process are introduced, and the experiment results are also discussed. The results show that the bonding interface exhibits good contact and electrical property.
Preparation of PLA and PLGA Magnetic Microspheres with T-Shaped Microchannel Reactor
Authors: Liu Peng , Zhong Yi , Luo Yan
Published: April 2014

Monodisperse magnetic microspheres with biomaterial of polylactic acid (PLA) or poly lactic-co-glycolic acid (PLGA) as shell were successfully prepared via T-shaped microchannel reactor in this paper. Hydrophilic ferriferrous oxide (Fe3O4) with highly magnetic responsiveness was obtained by solvothermal method. Aqueous solution of Fe3O4 was then emulsified into a dichloromethane solution of PLA or PLGA to generate water-in-oil (W/O) emulsion. Different stabilizer, i.e. polyvinyl alcohol (PVA), gelatin or gum arabic, was then added into the W/O emulsion for the purpose of more stable system. Subsequently, W/O/W composite emulsion was formed by injecting W/O emulsion into PVA aqueous solution at the T-shaped joint of microchannel reactor. Magnetic microspheres were finally prepared by solvent evaporation in the microchannel. The characteristic functional groups of Fe3O4 were characterized by Fourier transform infrared spectroscopy (FT-IR). The magnetic property was measured with vibrating sample magnetometer (VSM). The morphology of all samples was observed by scanning electron microscopy (SEM). It was found that the magnetic microspheres exhibit a uniform particle size in micro-scale. Therefore, the T-shaped microchannel reactor was expected to create a new approach for fabricating magnetic microspheres.
Comparative Photocatalytic Properties of Cu2O from Octahedron to Sphere Structures
Authors: Qian Li Min , Zhou Jie , Zheng Chu , Chen Di , Shen Bi , Liu Yong Kun , Wang Li Xiao , Tong Yan Hua
Published: April 2014

Cu2O, a p-type semiconductor, has broad potential applications, especially as a visible-light photocatalyst. This paper presents a simple water-bath reflux to prepare Cu2O micro/nanoparticles. The morphology evolution from intact octahedrons to surface-pitted spheres was obtained by adjusting reducing agent and additive. Reflectance spectra show similar photo-absorption intensity and the same range from 250 nm to 650 nm. However, they perform different photocatalytic activity. Intact octahedron has the best photodegradation ability and next is vertex-and edge-damaged octahedron, the lowest for vertex-free polyhedrons and surface-pitted spheres. The enhanced photocatalytic activity for intact octahedrons should to be attributed to its surface characteristics of high index. Our study not only provides a simple method for controllable preparation of Cu2O micro/nanoparticles with different morphologies but also confirms the effect of morphologies on photocatalytic activity.
Preparation and Application of Macropore Nanometer Host-Guest Catalyst
Authors: Ding Wei , Wang Ding Cong , Zhao De Zhi , Ke Ming
Published: April 2014

A series of macropore host-guest catalysts were prepared by third nanoassembly technique. nanoassembly support had a pore volume of 1.32cm3 /g,a specific surface area of 220m2/g, average pore diameter of 27.3nm, the most probable pore diameter of 40nm, a low stacking density of 0.34g/cm3. The results of the XRD and TEM showed that the part of pore was blocked with increasing the amount of active metal. But the aggregation phenomenon was improved by adding uniformly co-impregnant, and the amount of active metal was up to 40%. The lamellar structure of sulfided state metal was formed which the length were between 8 nm to 10 nm and layer were 3~9. Hydrogenation performance of the different catalysts has been evaluated. The removal rates of desulfurization, denitrification, residual carbon and demetalization for hydrotreating in one gram active metal per 100mL volume for FB30 were as 2.0, 2.6, 2.0 and 2.5 times as FC, respectively. The results explained that the macropore host-guest catalyst had higher activity for hydrotreating residue.
Evolution in Dislocation Configuration of Deformed Fe-40Ni-Ti Alloy during Isothermal Relaxation
Authors: Yuan Shao Qiang , Zhang Xiao Juan
Published: April 2014

The thermo-simulation test and transmission electron microscopy (TEM) were applied to investigate the evolution of dislocation configuration and strain induced precipitation behavior during relaxation at 850°C in a deformed Fe-40Ni-Ti alloy. The stress relaxation curve can be divided into three stages, namely, the process of incubation, nucleation and growth, and the coarsening of strain-induced precipitates. The highly dense and twisted dislocations formed during the deformation develop into dislocation cells and finally, the sub-grains can be observed when relaxing to 1000s. The strain induced precipitates occur both onto the dispersed dislocations and dislocation cells. The precipitates pin the dislocations which results in retarding the progress of dislocation configuration evolution. As precipitates start to coarsen, the pinning effect weakens and the dislocations get rid of the pinning though bypassing mechanism. Adopting the same simulation test to bainitic steel, the optimum refinement could be obtained at 60-200s during relaxation processing, corresponding to the perfect dislocation cells formation of Fe-40Ni-Ti alloy.
Influence of Sonomechanical Treatment on the Structure of Cellulose Micro/Nano Fibrils
Authors: Wu Yan , Wu Zhi Hui , Zhang Xu Jun , Zhang Ji Lei , Yan Xiao Xing
Published: April 2014

The fast-growing Eucalyptus (E. Europhylla) was used as the raw materials to prepare for micro/nanocellulose fibrils. The morphology changes of cellulose by sodium hydroxide linkage ultrasonic energy treatment was discussed. The properties of treated cellulose was evaluated by X-ray , scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy. By the degree of crystallinity of the experimental test results showed that: a high concentration (17.5%, mass fraction) NaOH solution swelling with ultrosonication chemical pretreatment of cellulose prepared micro/nanofibrils change in crystal form, that is transformed cellulose I into cellulose II. However, the cellulose micro/nanofibrils remained crystalline cellulose I type after treated by a low concentration (2%, mass fraction) NaOH solution swelling with ultrosonicaion chemical pretreatment. High alkali activation sound chemical pretreatment increased the crystallinity of obtained micro/nanofibrils, the corresponding values were 89.2% and 86.3%. Observed by the scanning electron microscope that: a low concentration alkaline with ultrosonication chemical pretreatment increased the degree of sub-wire broom, the fiber surface area increased accordingly, and the fiber is more "open", so that the reaction activity of the cellulose fibers improved. The infrared spectrum showed that: the chemical changes between cellulose micro/nanofibrils and NaOH occurred after mercerization.
Fabrication, Characterization and Photocatalytic Activity of TiO2/Cellulose Composite Aerogel
Authors: Lu Yun , Sun Qing Feng , Li Jian , Liu Yi Xing
Published: April 2014

nanoTiO2/cellulose composite gels have been uniformly blended during the dissolving process of cellulose in ionic liquids (ILs). After the regeneration process, the obtained hydrogel was finally dried through supercritical CO2 to obtain the TiO2/cellulose composite aerogel. The structure and properties of the composite aerogel were characterized by XRD, SEM, FT-IR, UV-vis, and photocatalytic degradation tests. The porous structure and hydroxyl groups in the regenerated cellulose matrix provided cavities and affinity for the immobilization of TiO2 in the cellulose gels through electrostatic and hydrogen bonding interactions. The TiO2/cellulose composite gels exhibited a good photocatalytic activity for photodegradation of Rhodamine B (RhB) under UV light irradiation. This research highlights another opportunity for the development of the portable and flexible photocatalyst.
Fabrication of Filter Film Using in Polarized Light Guide Prism System
Authors: Liu Dong Mei , Wang Xiao Juan , Fu Xiu Hua , Wang Shuai , Pan Yong Gang
Published: April 2014

Aiming at the special requirements for filter film of the optical prismatic system, basing on the design theory, and choosing the appreciate film materials, a high reflectance film and a splitter film are designed respectively. The films can satisfy with the optical requirement perfectly, when the incidence light is P polarized at the 25 angle in the range of the visible wavelengths (450nm~650nm). During the preparation process, the optical film absorption is solved by continually optimizing the process parameters, such as temperature, rate of evaporation and ion assisted deposition parameters, etc. Meanwhile, the error produced in the process of preparation is analyzed and revised through several repeated tests and researches, so that the control precision of layer thickness is improved. Finally the high-reflective film with average reflectance over 99.5% in the 450~500nm band and the beam splitting film with transmittance and reflectance ratio of 1:1 and 1:2 are prepared respectively (both errors are below 1%) in the 450~650nm band. After the spectrum testing and analyzing, the spectrum curve shows that all the parameters meet the basic requirements for usage.
Research of Removable Electrodes Based on Microfluidic Chip
Authors: Han Xiao Wei , Liu Xiao Wei , Tian Li , Wang Wei , Zhang He , Mao Zhi Gang
Published: April 2014

We research removable electrodes based on microfluidic chip in this paper. The electrodes can be assembled and fixed quickly and easily. We could change toxic electrodes conveniently during experiment. In addition the design of removable electrodes fits different size of channels, because the detection electrodes could be set its position close to outlet of microchannel under the microscope. We provide numerical simulations of COMSOL and hotomicrographs to proving our design in this article.
A Microfluidic-Based Trapping and Positioning Method for Single Cells
Authors: Zhang Qin , Xu Chen Ying , Huang Wei Jun , Aoyama Hisayuki
Published: April 2014

Trapping and positioning of single cells has played a major role in various fields of bioengineering, such as cell screening, analysis, induction and pathologic diagnosis, etc. In this work, we report a new non-contact microfluidic-based method for single cells trapping and positioning. A pair of microtubes of same specification is symmetrically placed on opposite sides of the cell. When fluid flowing through microtubes squirts in the same velocity toward the cell, the cell will be immobilized and clamped due to symmetrical fluid pressure generated around it. Feasibility of the reported method is validated by experiments. This method is also capable of trapping and positioning micro particles.
Design of Microwave Reconfigurable Equalizer Based on MEMS Technology
Authors: Jiang Wen , Han Lei , Liao Xiao Ping
Published: April 2014

In this paper, based on the design theory of CPW equalizer with low VSWR, microwave reconfigurable equalizers with various equalization curves have been designed. The combined structures of the reconfigurable equalizer with low VSWR and small sizes via MEMS switches have been optimized by ADS and HFSS software. The equalizer can be used in the frequency range from 20GHz to 24GHz. With the control of switches, the reconfigurable equalizer can realize the variation of the equalization curves and achieve the minimal insertion losses of around-1dB, respectively. In order to improve the minimal insertion losses, a matched structure has been presented. The matched structure reduces the minimal insertion losses compared with the former structure significantly.
Method to Design and Fabricate a Novel RF MEMS Switch
Authors: Zhang Nai Bo , Mei Li Rong
Published: April 2014

This paper presents a RF MEMS shunt switch with design, fabrication and measurement. The designed switch that avoids unstable and collapse could be used to RF MEMS devices. The photoresist is used as sacrifice layer and switch material is Aluminum. To make the surface of MEMS switch smooth, the method of multiple spreading thick photoresist and dry etching is proposed. A size of 130×230 (μm)2 MEMS switch with 1 μm height and 0.45 μm unevenness is demonstrated in a configuration. Continuous tuning of 1 μm is achieved by loading 33 volt DC voltage between MEMS switch beam and signal line. The RF performance shows 0.1-0.4dB insertion loss and 18-30 dB return loss of the switch. The fabrication, design, and measurement results of the MEMS switch are detailed.
Thermoelectric Device Based on Vertical Silicon Nanowires for On-Chip Integration
Authors: Wang Zhen , Qi Yang Yang , Zhang Ming Liang , Ji An , Yang Fu Hua , Wang Xiao Dong
Published: April 2014

A fabricating process of prototype thermoelectric device based on vertical silicon nanowires (SiNWs) for on-chip integration was presented. The SiNWs with diameter of 200 nm and height of 1 μm were fabricated by electron beam lithography and inductively coupled plasma etching. The gaps between the NWs were filled by the spin-on glass, which isolated the top and bottom electrodes. A serpentine platinum resistance thermometer coil was formed on the NWs to create temperature gradient across the NWs and measure the temperature of the top of NWs. I-V characteristics of the vertical device before and after annealing were measured. The nonlinear I-V curves were obtained, but the annealed one demonstrated 1000-fold reduction in resistance than the unannealed one.
The Fabrication of Trans-Scale Micro-Fuze Safety Device
Authors: Du Li Qun , Wang Ao An , Zhao Ming , Song Man Cang
Published: April 2014

Fuze Micro-Electro-Mechanical System (MEMS) has become a popular subject in recent years. Studies have been done for the application of MEMS-based fuze safety and arm devices. The existing researches mainly focused on reducing the cost and volume of the fuze safety device. The reduction in volume allows more payloads and, thus, makes small-caliber rounds more effective and the weapon system more affordable. At present, MEMS-based fuze safety devices are fabricated mainly by using deep reactive ion etching (DRIE) or LIGA technology, and the fabrication process research on the fuze MEMS safety device is in the exploring stage. In this paper, a new trans-scale fabrication method of metal-based fuze MEMS safety device is presented based on UV-LIGA technology and the micro Wire-cut Electrical Discharge Machining (WEDM). The method consists of fabrication of micro-spring by UV-LIGA technology, the fabrication of mesoscale structure by WEDM, the micro assembly of micro spring and mesoscale structure. Because UV-LIGA technology and WEDM technology were introduced, the production cycle was shortened and the cost was reduced. The overall dimension of the micro-fuse safety device is 9.5×12.3×0.6 mm and the smallest dimension is 10μm. Besides, four problems in the fabrication process have been solved effectively, which is helpful for the fabrication of similar kinds of micro devices. The fabrication method presented in this paper provides a new option for the development of MEMS fuze.
The Vibration Pickup of Micro-Pump Diaphragm Based on MEMS Technology Design
Authors: Li Gang , Li Lei , Zhao Xiao Feng , Wen Dian Zhong , Yu Yang
Published: April 2014

This paper designs a micro-pump silicon diaphragm vibration pickup sensor. In this newsensor which is based on piezoresistive effect, four MOSFETs with nc-Si/c-Si heterojunction drainand source are manufactured on the surface of silicon wafer by using the technique of CMOS andPECVD, at edge of <100> orientation of the N-type silicon diaphragm rectangle, and using MEMStechnology, the back of the four MOSFETs device silicon substrate processed into silicon cup, whichconstitutes the vibration pickup sensor. The micro-pump silicon diaphragm vibration pickup sensornot only has all the advantages of conventional force sensitive resistance vibration pickup sensor, butalso has the advantages of small temperature drift, high detection precision, and it can satisfy themicro-pump silicon diaphragm vibration requirements.
Effect of Strain Rate on the Simulation of MEMS Safety and Arming Device
Authors: Ma Wen Rui , He Guang
Published: April 2014

Under launch impact load, LIGA nickel that manufacturing MEMS fuze safety and arming (S&A) device will have obvious strain rate effect. By using finite element analysis software ANSYS/LS-DYNA, simulation models of a small-caliber ammunition MEMS fuze setback S&A device with strain rate effect and without strain rate effect were respectively established. The results of the two simulation modules were quite different. Comparisons between experimental results and simulation results show that simulation results considering strain rate effect agree well with experimental results, which proves strain rate effect should not be ignored in the simulation of MEMS S&A device.
Compact Compound Imaging System with Large Target Surface
Authors: Dong Ke Xiu , Wei Nan Nan , Shi Jian Ping , Wang Yan Qin
Published: April 2014

Compact compound imaging system with large CCD target surface has been researched. The target surface reaches 50mmX50mm, and reduces the system processing and installation difficulty. We present the system overall plan and discuss the imaging characteristics. The imaging results for sector resolution target show that the system can image with multi channel crosstalk free. The results show that whether the single convex lens system or double convex lens system, the definition and contrast of single channel graphs are poor. However we can get the super resolution image by POCS algorithm. The reconstructed results show that image quality has been obviously improved compared with the single channel image, which proof the availability of the compact compound imaging system with large CCD target surface. Key words: Compact ompound imaging system, Microlens array, Doublet lens, POCS
Sustained-Release Performance In Vitro of BCG/Fe3O4/Chitosan Thermosensitive Gel Integrated Material for Irrigation Therapy of the Bladder Tumor
Authors: Wu Cheng Ge , Sun Kang Ning , Li Ai Min
Published: April 2014

Tumor of bladder is one of the most common tumors of the urinary system, the vast majority of which come from the epithelial tissue, and of which more than 90% are transitional cell tumors. Tumor of bladder ranks fourth in men and tenth in women. Intravesical instillation of Bacillus Calmette-Guerin (BCG) is recognized as the best way to prevent the recurrence of bladder cancer. But BCG would be excreted with the urine after staying about one hour in the bladder, which has a serious impact on its efficacy. In addition, repeated infusions bring great pains to the patients. This research intends to design a new sustained-release BCG integrated composite materials based on homogenized freeze-dried BCG. The release experiments in vitro of the composite materials show that the release property is good and release time of BCG is more than 48 hours.
The Influence and Control of Encapsulation Moisture in MEMS Gyroscope
Authors: Guo Ya Bei , Yu Hui , Lu Wen Yi , Jin Xiao Feng , Zou Jiang Bo
Published: April 2014

MEMS gyroscope can be used in various field such as stabilization, controlling and guiding, navigation and so on. Bias variation over temperature is the key performance in MEMS gyroscope. The encapsulation moisture has great influence on the bias variation of MEMS gyroscope.By experiments on gas recharged, roast temperature, die attach adhesive and encapsulation shell, method to depress the encapsulation moisture is obtained.
By DPA, the encapsulation moisture of sensing element encapsulated by the reformative method can be reduced to less than 1000 ppm, and the performance on temperature of MEMS gyroscope is improved.
A Micromachined Glucose Monitoring Sensor with Diffusion Control
Authors: Liu Ya Xin , Song Xiu Shan , Yao Yu Feng , Huang Bo , Zhong Ming
Published: April 2014

Considering the long-term, flexible blood glucose monitoring demand, a sensor monitoring system for interstitial fluid (ISF) ultrafiltration sampling and on-line monitoring of blood glucose is presented. In this paper, the glucose sensor chip used in this system will be introduced in detailed. This sensor chip was developed by MEMS technique and it has the advantages of less ISF consumption, smaller structures and easier integration. Otherwise, the silicon glucose sensor chip is provided with diffusion control of the analyte through a porous silicon membrane into a silicon etched cavity containing the agarose immobilised enzyme. First, glucose monitoring principle of this sensor system will be intrudouced briefly. Then, this paper focuses on the design and fabrication of the key component, which is the MEMS sensor chip with diffusion control. Finally, experiments were carried out, and results show that the sensor chips signal response time at increasing glucose concentrations is about 5s; The linear range is large enough to cover the required broad area of blood glucose (0.2 ~ 20 mmol / L), the sensitivity is 9.76 nA/mmol.L-1, and the correlation coefficient is 0.9954. In addition, experiments results of sensor chip with different pore membrane were compared with each other. We can see that different measuring range and sensitivity can be obtained, which agrees with the theoretical analysis.
Performance Test for Nanometer Accuracy Capacitance Displacement Sensor
Authors: Cui Jian Jun , Qu Xing Hua , Kang Yan Hui
Published: April 2014

In checking to see the performance of the nanometer accuracy capacitive sensor, some parameters, such as, the linearity, repeatability and so on are presented as the characterization parameters. Firstly, the series of test method and test devices is designed to measure and evaluate these parameters of a capacitance sensor. Secondly, the measuring setup is consisted by the traceable laser interferometer with high accuracy and nanometer micro-motion system. Finally, in order to meet the displacement linearity test, the measuring method is in line with the Abbe principle. Experimental results indicate that this approach and setup can realize in the best reference line to the minimum linearity is better than 0.01%, repeatability is better than that of 3.5nm, resolution is less than 0.3nm, measurement capability is more unwavering than 3nm. It can satisfy the measurement requirements of capacitance sensor performance testing with nanometer accuracy.
Design of the Digital in Signal Processing Platform of the Gyroscope Based on FPGA
Authors: Wang Di , Zhou Jia Jun , Chen Song , Yao Ying , Yin Liang , Liu Xiao Wei
Published: April 2014

Gyroscope is a sensor thatmeasure angular velocity which is widely used in various fields [1]. The analogprocessing technology of Gyro-signal is very mature, but due to the noise andother shortcomings of the analog circuit, the development of micro-mechanical gyroscopeis limited. Digital gyroscope has superior performance and accuracy, so thesignal processing of gyroscope will take digital methods [2]. This paper designsa platform for the digital signal processing of Silicon gyroscope. By using FPGAextend A / D and D / A interface method implement the signals from outside inputto output, build a digital signal processing platform of the minimum system,then design the overall digital signal of the hardware part and the controlsection of the software part, synthesis the designed platform which doesn’tdepend on crafts use the Xilinx Synthesis tool and gave the synthesizedresults, verify the correctness of the design eventually.
The Structure Design and Simulation of the Ring Resonator Based on SOI Planar Optical Waveguide for the Micro Biochemical Sensor
Authors: Du Yang , Dong Ying
Published: April 2014

A ring resonator based on Silicon-on-Insulator (SOI) planar optical waveguide for micro biochemical sensor application is designed and simulated in this paper. The SOI optical waveguide is made with a ridge structure. According to the optical waveguide mode theory and the performance of the ring resonator, the size of the single mode ridge waveguide and the structure of the ring resonator are obtained. Based on the structure principle and the transmission mechanism of electric field of the ring resonator, the power transfer function and the parametric equation of sensitivity are derived. As a result, the value of Q of the ring resonator can reach 103 magnitudes. At last, the structure and the transmission mechanism of electric field in the ring resonator are simulated in MATLAB software.
Experiment Research on Array Grouped by MEMS Vector Hydrophone
Authors: Liu Meng Ran , Jian Ze Ming , Liu Hong , Song Xiao Peng , Zhang Guo Jun
Published: April 2014

As a new type of underwater acoustic sensors,the principle of the MEMS hydrophone is introduced in this paper.MUSIC is a algorithm for estimating the parameter of the signal and it has a high resolution.In order to verify DOA estimation performance of MEMS vector array,experiment has been done.the experiments results showed that the MEMS vector array can achieve DOA estimation and track the underwater moving target.thus,it is concluded the feasibility of the MEMS vector array.
Design of Road Condition Sensor Based on Multiple Frequency Detecting Technology
Authors: Dong Xue Peng , Han Lei , Yin Gang Yi , Cai Lei
Published: April 2014

Road surface sensors system, plays a very important role in the highway traffic field. Comprehensive estimation of road condition, will distinctly enhance the safety of transportation. Road condition sensor is used to distinguish the coverings on road surface, such as water, snow, ice, frost and so on. In this paper, we introduce the multiple frequency detecting technology used in the road surface sensors system, and design the road condition sensor to detect coverings on road surface. The main work includes design, measurement and improvement of the sensor.
Design of Charge Pump for Inertial Sensor Drive Circuit
Authors: Yao Fang Fang , Zhang Xiao Jing , Gao Zhi Qiang , Liu Xiao Wei
Published: April 2014

A transistor-level circuit design of charge pump is introduced to drive the inertial device. The design is made of several big modules, including main charge pump module, band gap reference module, comparator module, oscillating module, control module, temperature protection module. A three-stage charge pump is applied to achieve 5 V to 18 V DC/DC conversion, and each stage uses the cross coupled charge pump circuit, taking body effect, threshold voltage drop and efficiency into account. Considering efficiency and power consumption, the band gap reference module adopts a self-biased op amp. To make the comparator transient response fast, the op amp cascades two inverters. The temperature protection module sets a maximum temperature to protect the charge pump. The control module is composed of a data selector, a two-phase non-overlap clock circuit and a frequency divider to optimize clock signal. Then simulations are given and the charge pump is analyzed, finally the efficiency of charge pump is calculated. Designed in CSMC 0.5um process, the charge pump has an efficiency of 87.63 percent, a 19.85V output voltage, a 100 mA output current, and 6.05mV ripple.
Mixed Mode Driving Circuit of Quartz Gyroscope Interface Circuit
Authors: Zhou Yu Feng , Li Yang , Ma Zhen , Liu Xiao Wei
Published: April 2014

QRS is widely used in many areas and the driving voltage is the key to the proper functioning of QRS. In this paper, a new mixmode driving circuit is presented.The circuit uses both square wave and sine wave to drive QRS which can adopt their good points and avoid their shortcomings. The simulation results show that in this circuit, the oscillation is stabilized within 8ms and the range of frequency is 11.68kHz ~11.69kHz. The distortion factor of the driving circuit is 3.22% which makes the circuit much more satisfying.
Research on the Phase Difference Extraction Algorithm of the Free-Drive Three-Axis MEME Gyroscope Used in Spinning Projectiles
Authors: Zhang Xiao Ming , Duan Xiao Min , Shang Jian Yu , Zhao Dai Di , Liu Jun
Published: April 2014

The output signal of the free-drive three-axis MEMS gyroscope used in Spinning Projectiles contains rolling is sine period signal. In order to demodulate the yawing and pitching angular rates, extracting the fringe phase information is needed. It is difficult to realize the phase demodulation of single signal. To solve this problem, reference signal is provided. The phase of the gyroscope is extracted by computing the phase difference. Then, three methods of phase difference measurement are introduced and simulated by MATLAB. According to the signal feature, the contrastive analysis of measurement error is made and the maximal precision of measuring method for phase difference is obtained. The last part is the analysis of performance.