bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Characteristics of Mercury Droplet Flow in Micro Acceleration Switch
Authors: Liu Ting Ting , Su Wei , Yang Tao , Han Bin , Wang Chao
Published: July 2013

Unlike the solid-solid contact of traditional micro acceleration switch, liquid metal can be utilized to solve the disadvantage of solid-solid contact, such as contact wear and signal bounce. Liquid-metal micro switches have demonstrated no contact bounce, low switch-on time, low contact resistance, long life, and the capability to handle large currents. So the liquid-metal micro acceleration switches have attracted researcher’s attentions increasingly. To investigate the flow characteristics of mercury droplet in micro acceleration switch, this paper establishes numerical models of micro acceleration switch by using FLUENT. The effect of contact angle, droplet volume and temperature are discussed in this paper. Based on the VOF-CSF model of FLUENT, a serial of simulations were performed. The simulation results show that the influence of contact angle and droplet volume on flow characteristics is serious, and the influence of temperature is small. As compared with theoretical analysis, simulations are in good agreement with theoretical analysis.
Nonlinearity Analysis of Closed-Loop ΣΔ Micro-Mechanical Accelerometer
Authors: Liu Xiao Wei , Xu Hong Lin , Lv Bing Jun , Zhou Jia Jun , Chen Song , Yang Jian
Published: July 2013

A high-order interface circuit based on sigma-delta (ΣΔ) modulation is advantageous to enhance the resolution and reduce the quantization noise of micro-accelerometer, while the performance is restricted by the effect of nonlinearity of op-amp, electrostatic force feedback and quantizer. A fifth-order closed-loop ΣΔ capacitive accelerometer is proposed in this paper and a theoretic nonlinearity of the accelerometer was investigated. The nonlinear behavioral models based on SIMULINK are given in the paper. The simulation and test result are presented through optimization based on the nonlinearity analysis at last.
An Improved Phase Lock Loop for Micromechanical Gyroscope with a Carrier Modulation
Authors: Hu Shi Chang , Zhu Hui Jie , Ma Ming Jun , Liu Yi Dong , Jin Zhong He
Published: July 2013

This paper presents an improved phase lock loop for a micromechanical vibrating gyroscope with a carrier modulation. The loop keeps the gyroscope working at the resonant frequency of its drive mode. Digital signal processing is adopted in design of the loop and Xilinx virtex4 series FPGA is used. Compare with the conventional way, it decreases the resources in FPGA including registers, LUTs, and DSP48s. The realization shows a reduction of 51.06% for registers, 52.68% for LUTs and 18.18% for DSP48s. Besides, the loop has good portability for different devices which have different resonant frequencies due to the fabrication error. No adjustment is needed unlike the conventional loop whose reference phase has to be adjusted manually.
Portable-Surface Plasmon Resonance Biosensor Immunoassays for the Human Serum Albumin Detection
Authors: Li Hui , Zhang Lu Lu , Cai Hao Yuan , Chen Xing , Sun Jian Hai , Chao Ya Peng , Cui Da Fu
Published: July 2013

The screening of urine human serum albumin (HSA) is significant for the early diagnosis and intervention of the nephropathia. This study developed sensitive HSA detection assay with a self-made portable-SPR biosensor based on the reflection light intensity interrogation. Anti-HSA monoclonal antibody was immobilized onto the gold sensing area and a directive assay for HSA was developed. A detection range of 1–100μg/mL HSA was found. The described label-free, real-time immunoassay for the quantification of HSA in urine is a rapid, sensitive, alternative method available for the clinic detection.
A Novel Z-Axis Capacitance Accelerometer with Highly Symmetrical 16-Beam Structure
Authors: Li Wei , Che Lu Feng , Li Xiao Lin , Wu Jian , Wang Yue Lin
Published: July 2013

A novel highly symmetrical 16-beam sandwich structure Z-axis differential capacitance accelerometer is presented. In this design, the proof mass is suspended symmetrically by double-side of 16 straight beams with highly uniform dimension which can reduce the cross-axis sensitivity and rotational influences dramatically. Parameters of the beam-mass structure were analyzed and optimized by finite element analysis (FEA) software. The micro accelerometer is based on bulk-micromachining by DRIE and KOH anisotropic wet etching technologies. The beam-mass structure was released by anisotropic wet etching on both device layer sides simultaneously. The fabricated accelerometer was measured over the maximum range of 30g gravity field, results of measurement show that the close-loop sensitivity is 80mV/g, the nonlinearity is 0.27%, and the bias stability is 0.63mg for an hour.
Analysis of Magnetic Field for Micro Axial-Flux Electromagnetic Generator
Authors: Wu Tao , Fan Ning Jun , Wu Yan Xuan
Published: July 2013

This paper reports on the magnetic field distribution and magnetic circuit calculating method of micro generator. A micro axial-flux electromagnetic generator is designed as size of Φ6mm×3mm. Traditional magnetic circuit analysis methods are used to retrieve the air-gap magnetic density on no-load micro generator in operation. FEA is done for the micro generator model using magnetic field numerical simulation software. The main parameters of no-load magnetic field and the waveform of induced EMF are obtained. Comparing the results obtained from the magnetic circuit analysis and numerical simulation, the error of air magnetic density is less than 2.54% and the error of the maximum value of induced EMF is less than 2. 68%. The results suggest that magnetic circuit analysis methods can be used for magnetic field analysis of micro axial-flux electromagnetic generators, and be helpful to provide guidance for designs.
Electrospun ZnO Nanowires as Gas Sensors for Propanol Detection
Authors: Li Y. , Ding J.N. , Yuan N.Y.
Published: July 2013

We used an electrospinning method to produce ZnO nanofibers for propanol sensing. ZnO nanofibers were electrospun from a solution containing poly(4-vinyl phenol) (PVP) and zinc acetate. The morphology and structure of the as-prepared ZnO nanofibers have been characterized by scanning electron microscopy and X-ray diffraction, respectively. The calcination process of the ZnO/PVP composite nanofibers brought forth polycrystalline würtzite ZnO nanofibers with diameters of 50-70 nm. Under the optimized experimental conditions, the prepared product shows the desirable sensing characteristics towards propanol at 400°C. The high sensitivity, reversible response and good selectivity indicated its potential application as a chemical sensor.
Modeling of Vibratory Microgyroscope with Manufacture Errors Based on Parameters Identification Theory
Authors: Su Jian Bin , Wu Xue Zhong , Xiao Ding Bang , Chen Zhi Hua , Hou Zhan Qiang , Wang Xing Hua , Xin Yu , He Kun
Published: July 2013

This paper presents a modeling method of vibratory microgyroscope with manufacture errors based on parameters identification theroy. owing to the manufacture errors, such as quadrature error and cross-axis perturbation, the resonant vibrations of the drive mode to the sense mode are coupled not only through the Coriolis force. In reality, also by elastic forces, damping and so on. Accurate modeling and identification of manufacture errors enhance significantly the ability to compensate for the consequent errors via feedback/feedforward control strategies. In this article, a really direct model with manufacture errors of the microgyroscope is proposed and the parameters of the model are identified with Frequency-Response Analysis (FRA) and State-Space-based system-identification approach.
The Design of the Integrator of Sigma-Delta Modulator
Authors: Liu Xiao Wei , Chen Song , Liu Liang , Yang Jian , Chen Wei Ping
Published: July 2013

A kind of fully differential integrator is designed for the modulator of Sigma-delta ADC in this paper. Fully differential structure is adopted to enlarge the amplitude of output, restrain nonlinearity and increase competence of anti-interference. The frequency of signal in this design is 10kHz and the frequency of clock signal is 100kHz. The design of fully differential integrator, capacitive common mode feedback, two-phase unoverlapping clock and switched capacitor integrator are accomplished in this paper. The simulation results in Cadence using 0.5um process show that the low-frequency gain of operational amplifier is 69.87dB, unity gain bandwidth is 37.74MHz, phase margin is 67.73 degrees and slew rate is more than 31V/μs.
The Characteristics of MEMS Based Seismic Sensors Using the Electrochemical Approach
Authors: Fan Yun Jie , Wang Jun Bo , Deng Tao , Chen De Yong , He Wen Tao
Published: July 2013

The characteristics of MEMS based electrochemical seismic sensors (EC seismic sensors) are presented in this paper. A numerical model is set up, and a series of vibration test is established. The numerical simulation and vibration test results are illustrated and the difference between them is discussed.
Analysis of an Electrostatic Micro-Actuator Based on Vertically-Horizontally Bending
Authors: Tian Wen Chao , Yang Yin Tang
Published: July 2013

For the problems of the oversized voltage and undersized displacement in the electrostatic micro actuator of transverse loading recently, a silicon micro actuator model with characteristics of large-displacement and low-voltage is presented based on the principle of vertically-horizontally bending. The deflection equation of the micro actuator is derived. The axial static electricity, temperature stress and axial squeezing pressure on the deformation of micro-beam are analyzed. The simulation shows that the displacement is as big as 17.5μm when the driving voltage is as low as 5V. The displacement is much larger than the deformation of the current micro actuator.
Performance Comparison of Typical Electrothermal Actuators
Authors: Zhou Ling , Shen Xue Jin , Wang Zhen Lu , Hu Yi
Published: July 2013

As the power producer, the micro actuator is an important part of the micro electro- mechanical system, which is used as the conversion of energy, motion and force producing. In this paper, the mechanical models of three bent beam electrothermal actuators are summarized to make comparison with each other and analyze mechanical performance. For Π-shaped actuators, the tip displacements are proportional to temperature increment and length, having no relationship with the beam width and thickness. However, the displacement of Π-shaped actuators is smaller than the one of V-shaped actuators with the same parameters. For V-shaped actuators, the tip displacements of cascaded V-shaped actuators are larger than the ones of single V-shaped actuators with the same parameters. Especially, cascaded V-shaped actuator with secondary beam having no current has the largest displacement.
Research on MEMS Based Real-Time Measurement System for Motion Information of the Vehicle
Authors: Zhao Fei , Zhou Zhao Ying , Xiong Ji Jun , Zhao Ji Feng , Liu Jia Jin
Published: July 2013

This paper presents a new type of measurement and recording device for motion information of the vehicle, and proposes proposes a method of the multi-sensor data fusion. The system utilized a kind of MEMS-Based sensors, such as the angular rate gyros, the accelerometer, the magnetometer, the absolute pressure sensor, the differential pressure sensor and the GPS module. It is for measuring vehicle`s angular rate movement, acceleration, magnetic heading, altitude, air speed, latitude and longitude coordinates respectively. The entire system is integrated in a small circuit board with a small size, low power and high-stability characteristics.
Resonant Point Tracking and Locking Technique Based on Microsphere Resonator
Authors: Xu Peng Fei , Zhang Jian Hui , Ma Ke Zhen , Yan Shu Bin , Zhang Wen Dong
Published: July 2013

Abstract. Microsphere resonator is widely studied for the high quality factor Q and small mode volume. Aimed at the sensor applications, the resonant point tracking and locking method is proposed for measuring the resonant frequency shift. To avoid external noises, such as air flow and vibration, spot-packaged coupling structure is adopted. The robustness of microsphere-taper coupling unit is greatly improved. And this lays a foundation for resonant point tracking and locking. By employing modulation method, the demodulation signal is obtained. To lock the laser frequency to resonant point, PID circuits will adjust the center frequency of laser until the intensity of demodulation signal becomes zero. In the experiment, resonant tracking and locking is realized on the rotating platform with rotation rate 2 r/s.
An Interstitial Fluid Transdermal Extraction Chip with Vacuum Generator and Volume Sensor for Continuous Glucose Monitoring
Authors: Yu Hai Xia , Li Da Chao , Ji Yong Jie , Zhang Xiao Li , Xu Ke Xin
Published: July 2013

A five layer microfluidic chip which is designed and fabricated for interstitial fluid (ISF) transdermal extraction, collection, and measurement toward the application of continuous and real-time glucose monitoring is presented in this paper. The microfluidic chip consists of a Venturi tube generating vacuum for ISF extraction and fluid manipulation, a novel volume sensor of electrolytic fluid for normal saline input volume control and ISF volume measurement, pneumatic valves for fluid management, and access ports for glucose sensor integration. The output vacuum of the Venturi tube is tested, and a less than 88kPa vacuum has been achieved, when 220kPa external pressure is applied. The feasibility of using the volume sensor to control and measure the normal saline input volume is confirmed by high accuracy and low coefficient of variation (CV=0.0040, n=12). The microfluidic chip is ready for glucose sensor integration in continuous glucose monitoring.
Bubble-Induced Relaxation in High-Pressure Microfluidic Systems
Authors: Wang Bao Jun , Xie Fei , Wang Wei , Wu Wen Gang , Li Zhi Hong
Published: July 2013

This work reported an analysis of a noticeable relaxation phenomenon caused by undesirable air bubbles in high-pressure microfluidic systems. A model with compression of air bubble considered was established to address the experimental observed pressure relaxation. The results indicated that the dominative factors were flow rate, flow resistance and initial diameter of the trapped air bubble. Meanwhile, the calculated relaxation times in different cases provided a design guideline for high-pressure microfluidic chip to avoid the long-term pressure relaxation.
Effects of Anode Serpentine Flow Fields on the Performance of μ-DMFC
Authors: Fang Shuo , Zhang Yu Feng , Fu Wen Ting , Liu Xiao Wei
Published: July 2013

This paper dedicated to the investigations of anode mass transfer characteristics of single serpentine, double serpentine, triple serpentine and quadruple serpentine flow fields to choose the best flow field structure. In this paper, the structure sizes of anode different serpentine flow fields have been designed to make the same duty cycle based on the theory analysis. Then a multi-physics 3D model has been established and simulated to analyze and compare mass transfer characteristics of every serpentine flow fields including pressure distributions, velocity distributions and concentration distributions. The current collector plates containing different serpentine flow fields have been made by micromachining. To verify the simulation analysis, the μ-DMFCs with different serpentine flow fields have been packaged and tested. Compared with the simulations, the experiment results come up with the conclusion that the performance of μ-DMFC with double serpentine flow field is a bit higher than those with others. In conclusion, though the cell performance with double serpentine flow field is a bit higher than that with others, its fabrication process is so complicated and the improvement of the performance is not obvious. It is concluded that increasing the serpentine channels of anode flow field doesn’t have many benefits on the cell performance.
Studies on Preparation of Diet Microcapsules by Using Digitalization of Microfluids Technology
Authors: Yang Mei , Hou Li Ya , Li Zong An , Mu Li Li , Zhang Wei Yi
Published: July 2013

The traditional methods used to prepare diet microcapsules have disadvantages of expensive, complicated operation and harsh preparation conditions and so on. In this paper, based on the Digitalization of Microfluids Technology, a new method for preparing and research diet microcapsules is proposed, in which a kind of electromagnet is used as the actuator. Two kinds of micronozzle, one is the single micronozzle, and the other one is micronozzle array, are used to prepare diet microcapsules, and the influence of the system parameters on the stability of microcapsule preparation is explored. Results show that the sizes of the diet microcapsules could be controlled by changing the inner diameter of the micronozzle, the diet microcapsules could be prepared efficiently and steadily by the frequency of 7-11Hz range cooperated with other system parameters. Compared with the traditional methods, this method has the advantages of low-cost, mild preparation conditions, good controllability, and no limit to material and so on. With these obvious advantages, the technology offers researchers a tool to prepare diet microcapsules contain a variety of nutrients.
Preparation of Thermoresponsive Chitosan Polymers and Its Application Controlling Release of Antifouling Agent
Authors: Xu Feng Ling , Lin Cun Guo , Zheng Ji Yong , Zhang Jin Wei , Wang Li
Published: July 2013

Thermoresponsive chitosan copolymers embed with antifouling agent paeonol in chitosan(CS) microparticles were prepared and the release dynamics was studied at different temperature. Chitosan microparticles have been formed based on ionic gelation process of CS and sodium tripolyphosphate (TPP). Paeonol was incorporated into the CS microparticles with the size about 0.1 μm. The physicochemical structure of samples was analyzed by FTIR and scanning electron microscopy (SEM). We investigated the influence of sodium tripolyphosphate (TPP) and paeonol on Encapsulation efficiency. Increasing TPP concentration from 1 to 3 mg/ml increased encapsulation efficiency of paeonol from 63% to 92%. Increasing peaonol concentration from 1.0 to 3.0 mg/ml increased peaonol encapsulation efficiency from 72% to 85%.
The Design of High-Frequency OTA-C Filter for Wireless Sensors Network Applications
Authors: Gao Zhi Qiang , Zheng Wei , Yin Liang , Liu Xiao Wei
Published: July 2013

The paper is presented the design of high-frequency OTA-C band-pass filter with on-chip automatic tuning. In this design, the linear operational transconductance amplifier (OTA) is proposed based on fully complementary differential pairs with source degneration, and achieves both low-distortion figures and high-frequency operation. The matching design between the master filter and the slave filter is also given, and the non-ideality effect of the OTA-C filters with on-chip automatic tuning is discussed. The whole circuit is designed using TSMC 0.18μm 1.8V CMOS process and post-simulation results show the center frequency of filter is 105MHz with relative error of 0.4%, when the process corner varies between SS, TT, FF, and the temperature from-20 to 120°C.
Application of Electrical Resistance Tomography to Ice-Water Two-Phase Flow Parameters Measurement
Authors: Zhang Jian Guo , Ma Fu Chang
Published: July 2013

Abstract. The pipeline transport system of ice-water mixed fluid applies widely (e.g., ice cold storage system). Ice-water two phase flow is a non-settlement flow with viscous particles. Due to its complexity and variability, the correct parameter measurement of ice-water two phase flow, in terms of ice packing factor (IPF) and phase distribution, is an extremely challenging task. Electrical resistance tomography (ERT) is a novel imaging technology that can display cross-sectional electrical conductivity distribution within a pipe by using a tomography reconstruction algorithm. Compared to computerized tomography (CT), which is a standard tool in medical diagnostics and non-destructive testing of materials, ERT has many advantages in cost, speed and safety. The work described here is to study and learn about ERT implementation in measurement parameters of ice-water two-phase flow. In experiment the reconstructed image clearly display the phase distribution of ice and water in two-phase system. The research results prove that it is possible to monitor on-line the transportation process of ice-water two-phase flow using ERT system.
Effect of pH on Hard Disk Substrate Polishing in Glycine-Hydrogen Peroxide System Abrasive-Free Slurry
Authors: Chen Si Si , Lei Hong , Chen Ru Ling
Published: July 2013

The effect of pH on the material removal rate (MRR) and surface roughness (Ra) of hard disk substrate in glycine–hydrogen peroxide system abrasive-free slurry was investigated. The results show that, the MRR of hard disk substrate increases when both glycine and H2O2 are used in acidic slurries (pH=3.0) and decreases drastically in alkaline slurries (pH=10.0). The Ra of hard disk substrates is small in acidic slurries and increases drastically in alkaline slurries. Further, the effects of glycine, H2O2, and solution pH on hard disk removal were investigated by auger electron spectroscopy (AES), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. We also develop a reaction scheme describing the surface chemistry of the hard disk in this system.
The Study of Correlations among Parameters in Electrohydrodynamics Micro-Jet Printing System
Authors: Tan Jiao Jiao , Tang Zheng Ning , Wang Qi
Published: July 2013

Electrohydrodynamics (EHD) micro-jet printing technology has become a new method of micro/nano patterning and fabrication because of high resolution, good compatibility and simple structure. Firstly, stresses that Taylor cone meniscus subjected to under pulse voltage are discussed in EHD micro-jet printing system and tangential electric stress grows faster than normal electric stress, and tangential electric stress helps to “push” jet generation. Secondly, apply a pulse voltage superimposed over DC voltage, and investigate correlations between pulse frequency and drop spacing and then pulse frequency and drop diameter, and then compare and analyze the theoretic results with the experimental ones. Finally, as a result that it’s possible to obtain droplets with almost the same interval and desired size in the certain situation through controlling pulse frequency.
Analytical Method for Calculating Curvature of Circular Silicon Wafer Caused by Boron Doping
Authors: He Jiang Bo , Xie Jin , Zhou Wu , Qu Hao , Peng Peng
Published: July 2013

Doping can lead to residual strain and change of elastic properties in silicon. Residual strain makes silicon wafer exhibit curvature, which are used for fabricate MEMS structure. The boron doping profile is not uniform through depth, which makes doped silicon become a inhomogeneous material or Functionally Graded Material. For boron-doped circular single crystal silicon wafer, a analytical method which based on functionally graded plate mechanics theory, is proposed to calculate its curvature. Example was used to verify the analytical method through 3D finite element simulation.
Charge Storage Characteristics of Ni-NiOx Core-Shell Nanocrystals Embedded in SiO2 Gate Oxide
Authors: Ni He Nan , Wu Liang Cai , Hui Chun , Fang Ze Bo , Li Zhi Bin
Published: July 2013

The memory characteristics of Ni-NiOx core-shell nanocrystals (NCs) in the metal-oxide-semiconductor (MOS) capacitor structure were investigated. Scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) confirm the formation of the spherically shaped, well isolated, and uniformly distributed Ni NCs surrounded by NiOx (~1nm) in SiO2 gate oxide. The Ni-NiOx NCs embedded in SiO2 exhibited a large memory window of 9.8 V as well as efficient programming/erasing speed and improved retention characteristics of about 10 years. A possible band model needed for injection efficiency of carriers was given by considering the electron/hole barrier width and the additional interface states through the NiOx shell layer.
Chromium Atomic Deposits under the Disturbance of Straight Edge Diffraction
Authors: Zhu Bao Hu , Huang Jing , Zhang Wen Tao
Published: July 2013

The ideal Gaussian standing wave field model and the Gaussian standing wave field model under the condition of straight edge diffraction disturbance were established, and computer simulation and numerical analysis were done to the two kinds of models. It is concluded that the center position of Chromium atomic sedimentary grating in the straight edge diffraction disturbance standing wave will be away from the diffraction edge; near the given ideal deposit position, the PTVH(Peak to Valley Height) of Chromium atomic sedimentary grating in the ideal standing wave is higher than that in the straight edge diffraction disturbance standing wave, and the FWHM(Full Width at Half Maximum) is also narrower than in the ideal standing wave; for the exist of straight edge diffraction the size of the acceptable sedimentary pattern will be smaller, which has theoretical guidance on the practical operation.
Influence of Parameters on Fabricating TiO2 Nanotube by a Hydrothermal Method
Authors: Zheng Fang Fang , Zhang Wen Li , Zeng Xiong Feng
Published: July 2013

TiO2 nanotube was synthesized successfully with different parameters via hydrothermal process, using nanopowder TiO2 and concentrated NaOH solution as raw materials. If the hydrothermal temperature, hydrothermal time or washing conditions were changed, the structure of the nanotube was different. The phase compositions and morpholog ies of the TiO2 nanotube was characterized by XRD and SEM. These results suggested that the length of the nanotube increased from 180 nm to 270 nm, and the diameter almost kept a fixed level about 15~20 nm within a range of 110°C~150°C. The length of the nanotube increased from 230 nm to 330 nm and diameter was nearly unchanged as the result of time increasing from 24 h to 48 h. Washing conditions were very important to influence the nanotube. When the deposit was washed directly with distilled water, short and thick nanorod were formated, and microrod generated with concentrated hydrochloric acid, and microrod structure with smooth surface was produced with absolute ethyl alcohol, and the nanotube was fabricated only after washing by dilute acid.
Texturing Multi-Crystalline Silicon Wafer by Ultrasonic Standing Wave in Acid Etching
Authors: Chao Yan , Wu Li Qun
Published: July 2013

As a renewable, clear and inexhaustible energy, solar energy receives much more attention and has partly substituted traditional energies in many fields. Multi-crystalline silicon plays an important role for its low cost, abundant reserves and excellent photoelectric conversion in solar cells. Mixed acid etching is an effectively method to texture the morphology on the surface of mc-Si, While stochastic etching between silicon and acids results in irregular texturing and high reflectivity. In this paper, ultrasonic standing wave is introduced into acid solution, which aid wet etching to texture on the surface of mc-Si by controlling distribution of atoms of acids. Scanning electron microscope experiment shows that the morphology on the surface of mc-Si textured by this method is similar to that of mono-crystalline silicon. And the average reflectivity is 8%, much lower than mixed acid etching.
The Degradation of Polyesteramide Carbon Nanotube Composites
Authors: He Yi , Hai Peng , Ma Lan , Li Jin Bo
Published: July 2013

Polyesteramides (PEA) has both good heat resistance and degradability properties. In recent years, the Preparation of carbon nanotubes have became relatively advanced, but the reports of degradable nanocomposites and patents are less. In this paper, PEA/MWNTs (multi-walled carbon nanotubes) were synthesized using the in situ polymerization method, and the degradation in the air and alkaline was studied. The results show that MWNTs can be uniformly dispersed in the composited polyesteramides, the addition of MWNTs reduced the thermal properties of the PEA/MWNTs in the air. The PEA/MWNTs heat resistance and degradation rate in an alkaline solution were apparent changed in the content of the MWNTs is 0.7wt%.
A Novel Method to Modify the Lapping Uniformity for Silicon Wafer
Authors: Zuo Wen Jia , Du Xiao Hui , Zhang Hao Er , Su Yuan Zhe , Lei Ting Ping , Wang Ling Yun , Sun Dao Heng
Published: July 2013

In this paper, a novel lapping method based on regulating the position of carrier centroid is proposed to modify interfacial normal pressure uniformity. Eight special points are selected to represent carrier weight. This lapping process can be divided into initial stage, regulated stage and stable stage. The purpose of initial stage is calculating the position of carrier centroid according to the equivalent mass of eight points. The regulated stage is to decrease total thickness variation (TTV) by regulating the position of weight. Finally, the stable stage will keep uniformity of material removal rate (MRR) uniform at each point. A 3-inch and 400 μm thickness silicon wafer is lapped to demonstrate the feasibility of this method. We can find that TTV of this wafer decreases from initial stage 20 μm to 3 μm and remain constant. Therefore, the uniformity of MRR has been greatly improved by this novel lapping method.
A Novel Electrochemical Sensor for Formaldehyde Based on Platinum Nanoparticle/L-Alanine Modified Glassy Carbon Electrode
Authors: He Jia Hong , Xu Qiang , Song Zhong Rong
Published: July 2013

In this paper a novel and sensitive electrochemical sensor for the detection of formaldehyde was developed based on the platinum nanoparticles and L-alanine modified glassy carbon electrode. The sensor was fabricated by two steps. Platinum nanoparticles were immobilized on the electrode via electrodeposition method firstly, then the L-alanine was modified on the electrode by self-assembly method. The structure and morphologies of the Platinum nanoparticles were characterized by SEM and TEM. The electrocatalytic activity of the PtNP-L-alanine/GC electrode for formaldehyde detection in alkaline media was investigated via a series of electrochemical measurements. The PtNP-L-alanine/GC electrode show very high electrochemical activity toward formaldehyde. The oxidation peak current had a linear relationship with the formaldehyde concentration in the 0.3 µmol dm-3 to 4.0 mmol dm-3 range (R=0.9998), while the detection limit was estimated to be 34 nmol dm-3 (S/N=3). Such high sensitivity was attributed to the large surface area of the highly dispersed nanoparticles for electrocatalytic reaction and the fast electron transfer in the composite electrode. It demonstrated that glassy carbon electrode modified by platinum nanoparticles and L-alanine was suitable for the determination of formaldehyde.
Electrospinning and Characterization Nanofibres of Modified Konjac Glucomannan/PBS
Authors: Li Ying , Lin Xiao Yan , Luo Xue Gang
Published: July 2013

A composite nanofibers of modified konjac glucomannan (MKGM)/PBS were prerared by electrospinning process. The property of electrospinning solution and nanofibers were characterized by rheology, conductivity, surface tension and SEM. The diameter of nanofibers changed with addition of PBS, and the optional ratio for mixing MKGM with PBS is 6:4. The diameter of the nanofibers obtained at that ratio ranged from 236 to 1495nm, and the average diameter was 432nm.
Mechanism of Synthesizing Al2O3/Fe-Al Composites with Nano Al2O3 Fibers by In Situ Process
Authors: Lu Chen Jing , Ren Shu Xia , Wang Jian Lei , Yu Gang
Published: July 2013

In-situ composite of Al2O3/Fe-Al with Al2O3 fibers were prepared by partial oxidation of oxygen to Fe powder and Al power, crystal phase composition and elemental composition were analyzed by XRD, NORAN. The results indicated that, the crystal composition is determined by Aluminum content, when the content is enough, FeAl3, Al and Al2O3 will be gain, on the contrary, Fe2Al, FeAl, Fe3Al and Al2O3 will be gain; Al2O3 fibers were synthesized via VLS process, the quantity of Al2O3 fibers increased with the Al content, the whisker’s diameter was improved with increasing of sintering temperature.
Modified Nanocrystalline Cellulose Used for Improving Formaldehyde Emission and Bonding Strength of Urea Formaldehyde Resin Adhesive
Authors: Zhang Hao , She Ying , Song Shu Ping , Pu Jun Wen
Published: July 2013

Nanocrystalline cellulose (NCC) was used for improving the formaldehyde (HCHO) emission and bonding strength of urea formaldehyde (UF) resin adhesive in fiberboard and plywood. The original NCC was modified by 3-aminopropyltriethoxysilane (APTES) and the wetting property with UF resin adhesive was improved by 26.4%. The UF resin adhesive with modified NCC was characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TG) and Fourier transform infrared (FT-IR). The crystal region of UF resin adhesive was influenced by NCC and the diffraction intensity of the peak at 2θ = 22.82° was enhanced significantly. The thermal stability of UF resin adhesive with 1.0% modified NCC increased by 4.9%. And modified NCC led hydroxyl groups into the UF resin adhesive. HCHO emission and bonding strength of the UF resin adhesive with modified NCC were tested according to Chinese National Standards GB/T 17657-1999 and GB/T 9846-2004. The HCHO emission of fiberboard and plywood with 1.5% modified NCC decreased by 13.0% and 53.2%, respectively. The bonding strength of fiberboard increased by 158.3% (from 0.12 MPa of control group to 0.31 MPa of fiberboard with 1.5% modified NCC), while 1.5% modified NCC led to a 23.6% increase in the plywood.
Preparation of Cellulose Micro/Nano Fibrils by Sonochemical Method and its Morphological Characterization
Authors: Wu Yan , Wu Zhi Hui , Zhang Ji Lei
Published: July 2013

The eucalyptus cellulose micro/nano fibrils were prepared by using high intensity ultrasonication with chemical pretreatment. The basic characteristics of cellulose micro/nano fibrils were evaluated by wide-angle X-ray diffraction instrument (WAXD) and scanning electron microscopy (SEM).
Preparation of Expanded Graphite-Based Composite Electrode and Electrochemical Degradation of Phenol
Authors: Liu Cheng Bao , Chen Zhi Gang , Wang Tai Bin , Chen Feng , Gu Cheng , Cao Yu , Xu Zheng , Wu Zheng Ying
Published: July 2013

Expanded graphite-based carbon/carbon composite (EGC) electrode was prepared by compressed expanded graphite impregnated in sucrose-phosphoric acid solution. The porous texture and microstructure of the composite were analyzed by physical adsorption measurements of N2 adsorption at 77K and SEM. The influence of electrolytic conditions on the phenol degradation was investigated. The results indicated that the EGC electrode was comprised of a graphite framework coated by a thin layer of activated carbon. It could be used as an anode to degrade phenol effectively in the solution by electrochemical oxidation. The data in the experiment showed that the removal efficiency of phenol increased with lowering the initial phenol concentration, increasing the current density and electrolyte concentration.
Preparation and Characterization of Konjac/Gelatin Composite Nanofibrous Membranes
Authors: Du Xin Chen , Lin Xiao Yan , Huang Yuan Hao , Li Ying , Luo Xue Gang
Published: July 2013

A composite membrane of konjac/gelatin was prepared by electrospinning process. Gelatin and konjac were dissolved in acetic acid with different concentration and the resulting blend sol was electrospun into the composite nanofibrous membranes. The influence of technical parameters on morphology and diameter of nanofibers was investigated by Scanning Electron Microscope (SEM). The results show that the concentration of gelatin/konjac blend sol affects significantly on the fiber diameter and the morphology of composite membranes, and the increase of the voltage results in the decrease of the fiber diameter. The composite nanofibrous membranes with the average fiber diameter ranging from 356nm to 463nm were fabricated by electrospinning at the following conditions: 25% (w/v) of the concentration of gelatin/konjac blend sol (weight ratio of gelatin to konjac=125/1), 20KV of electric voltage, 0.0025mm s-1 of the feeding rate, 42°C of the electrospinning temperature and 15cm of receiving distance.
Reliability Study of the Band Gap of Rare Earth Oxides Measured by XPS Spectra
Authors: Yang Xiao Feng , Tan Yong Sheng , Fang Ze Bo , Wang Jian Jun , Ni He Nan , Li Zhi Bin , Chen Tai Hong
Published: July 2013

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Subscript textEr2O3、Tm2O3 and Yb2O3 films were deposited on Si (100) and quartz substrates by radio frequency magnetron technique. The energy gaps of the films were measured by X-ray photoelectron spectroscopy (XPS) and optical methods. The energy gaps of Er2O3、Tm2O3 and Yb2O3 are found to be 6.3±0.1、5.8±0.1 and 7.1±0.1 eV by optical measurements. For XPS measurements, the energy gaps of the films are 6.2±0.2、6.0±0.2 and 6.9±0.2 eV, respectively. The results show that using XPS to measure the energy gap of rare earth metal oxide film is feasible in an allowable deviation.
Research on Formation Mechanism of Black Silicon Based on Matter Wave
Authors: Wang Chen , Zhu Fu Yun , Sun Ming Zhu , Zhang Hai Xia , Zhao Xin
Published: July 2013

Most of research on formation mechanism of black silicon stays in the stage of experimental analysis. Consequently, it is quite difficult to perceive the mechanism of its formation process theoretically. In this paper, Quantum Mechanics is involved in our research on mechanism of how black silicon is formed in the fabrication process based on DRIE. Satisfying result is obtained through our simulation: Pillar structures with spacing raging from 500nm to 550nm can be formed when there exist particles with single momentum size in emulated experiment environment; With further efforts, more complicated pillar structures are obtained assuming that there exist particles with two sizes of momentum. By comparing with SEM image of black silicon, the simulated pillar structures are quite similar with real black silicon in both spacing and height distribution.
Cu (II) as a Catalyst for Hydrogen Peroxide System Abrasive-Free Polishing on Hard Disk Substrate
Authors: Wang Zhi Jun , Lei Hong , Zhang Wei Tao , Zhao Rong
Published: July 2013

With the continuous increase of the hard disk drive capacity, higher requirements are set for hard disk substrate to minimize roughness and defects of the polished surface. Recently, abrasive-free polishing (AFP) has attracted a great deal of attention due to AFP has fewer micro scratches and better cleaning ability than traditional chemical mechanical polishing (CMP). Our present work investigates the effectiveness of Cu (Ⅱ) as a catalyst for hard disk substrate AFP with H2O2 employed as an oxidizer. Polishing slurries used in AFP on hard disk substrate include deionized water, dispersant and oxidizer. The polishing experimental results show that the slurry of H2O2/Cu(Ⅱ) system has higher material removal rate (MRR) than H2O2 system in abrasive-free polishing on hard disk substrate. Further, the catalytic reaction mechanism of Cu (Ⅱ) in AFP of hard disk substrate was investigated. Compared with the H2O2 system, electron spin-resonance spectroscopy (EPR) analysis shows that the H2O2/Cu(Ⅱ) system provides higher concentration of hydroxyl radical. Potentiodynamic polarization measurements shows that corrosion currents (icorr) of disk substrate in the H2O2/Cu(Ⅱ) system is larger than that in the H2O2 system. The results imply that Cu (Ⅱ) as a catalyst for hydrogen peroxide system possesses promising prospects in abrasive-free polishing.
Synthesis of High Density Boron Nitride Nanotube Film
Authors: Liu Xiao Wei , Li Ling , Dai Ja Ne , Chen Ying
Published: July 2013

Antiwetting BNNT films have been achieved by milling-ink method. Superhydrophobic (CA <5°) are demonstrated on films with stainless steel as substrate. The high density and purity are confirmed by EDX and NEXAFS. There are only a few oxygen point defects in the form of nitrogen vacancies due to ink and annealing process in air.
The Effects of RE and Si on the Thickness and Cross Section Morphology of Zn-6Al-3Mg Alloy Coating
Authors: Li Shi Wei , Gao Bo , Tu Gan Feng , Sun Shu Chen , Yin Shao Hua , Hu Liang
Published: July 2013

Hot-dip galvanized steels are widely used in modern industry. The corrosion resistance and formability of them are closely related to the thickness and cross section microstructure of the hot-dip coating. In this paper, the effects of Si and RE on the thickness of Zn-6Al-3Mg alloy coating (ZAM) were investigated. Steel sheets were coated by using an experimental hot-dip galvanizing simulator. The thickness and cross section microstructure of ZAM coating alloyed with different content of Si and RE were characterized by using optical microscope and SEM, and element distribution was study by EDS. The results demonstrated that the reaction between Al from the bath and Fe form the steel sheets was suppressed by the addition of 0.1 wt. % Si to the Zn-6Al-3Mg bath, and the addition of RE effectively decreased the thickness of coating by means of improving the flowing property of the zinc alloy bath. Under the combined effects of Si and RE, the thickness of Zn-6Al-3Mg alloy coating went down from 33 μm to 10.1 μm.
A Short Ultrasonic Motor Stator with Square Base
Authors: Wang Rui Xia , Jin Long , Xu Zhi Ke , Hu Min Qiang
Published: July 2013

Length and support mode are the key to restrict the ultrasonic motor miniaturization. This paper presents a miniature langevin-type ultrasonic motor stator, it has both short length and simple support mode. With fixed-free ends, the stator adopts a square base and is fixed at its four corners. A new excitation mode is utilized to solve the problem of insistence of excitation position in the conventional excitation mode. Since the stator is unsymmetrical along the circumferential direction, there should be an optimal excitation angle. By using finite element method, axial displacement and radial displacement of nodes are achieved along the outer edge of the upper end of the stator when excitation angle is changed , then the results are analyzed and the conclusion can be reached that 45o is the optimal excitation angle. Finally, a photo of the stator prototype is presented.
Influence of Light Scattering Particles on Optical Properties of Polymer Diffusion Plate
Authors: Zheng Xiu Ting , Wang Hai Jun , Liu Ying , Wu Da Ming , Zhao Zhong Li , He Xiao Xiang
Published: July 2013

In order to analyze the influence of scattering particles on the optical properties of light scatter of polymer diffusion plate, we establish the microspheres of scattering particles in mathematical physics model. According to Mie scattering theory, we study the relationship between the scattering intensity distribution and the particle radius, the refractive index and the wavelength of the incident light. The results show that the particle radius is larger and incident wavelength is smaller, scattering intensity distribution is concentrated; the particle refractive index and scattering intensity distribution are not a simple corresponding relationship. At the same time according to the Monte Carlo method, the simulation is also used to analysis the effect that scattering particle concentration, the scattering particle radius and refractive index influence the diffusion plate light transmission rate and uniformity. The result shows that as the particle concentration is greater and transmittance is smaller, uniformity increases first and then decreases. As the particle radius is small, light transmission rate is higher and the particle refractive index is larger, light transmittance increases first and then decreases. But the relationship of the uniformity, the particle radius and the particle refractive index are all not simple corresponding law.
Leaching of copper refractory ore: Industrial application of a preoxidation stage
Authors: Van der Merwe Ryno
Published: July 2013

The use of a novel preoxidation method has been found to enhance the leaching of copper refractory ore in a continuous pilot plant setup. For the method to be incorporated into the processing flow sheet, the impact of high slurry density and temperature on preoxidation is established.
Terpenoid emissions from fully grown east Siberian Larix cajanderi trees
Authors: Kajos M. K. , Hakola H. , Holst T. , Nieminen T. , Tarvainen V. , Maximov T. , Petäjä T. , Arneth A. , Rinne J.
Published: July 2013

Abstract. While emissions of many biogenic volatile organic compounds (BVOCs), such as terpenoids, have been studied quite intensively in North American and Scandinavian boreal forests, the vast Siberian boreal forests have remained largely unexplored by experimental emission studies. In this study the shoot-scale terpenoid emission rates from two mature Larix cajanderi trees growing in their natural habitat in eastern Siberia were measured at the Spasskaya Pad flux measurement site (62°15´18.4" N, 129°37´07.9" E) located on the western bank of the Lena river. The measurements were conducted during three campaigns: 3–24 June, 8–26 July, and 14–30 August, in the summer of 2009. A dynamic flow-through enclosure technique was applied for adsorbent sampling, and the samples were analysed offline with a gas chromatograph. Between 29 and 45 samples were taken from each shoot during all three campaigns. Seven different monoterpenes, six different sesquiterpenes, linalool isoprene, and 2-methyl-3-buten-2-ol (MBO) were identified. The monthly median value of the total terpenoid emissions varied between 0.006 and 10.6 μg gdw−1 h−1. The emissions were dominated by monoterpenes, which constituted between 61 and 92% of the total emissions. About half of the monoterpene emissions were comprised of Δ 3-carene; α- and β-pinene had significant emissions as well. Linalool emissions were also substantial, comprising 3–37% of the total emissions, especially in June. Sesquiterpenes accounted for less than 3% and isoprene less than 1% of the total emissions. Based on the measured emission rates, the relative atmospheric concentration of each compound was estimated. Monoterpenes were the species with the highest relative concentration, while linalool and sesquiterpenes had a notably smaller contribution to the estimated atmospheric concentration than to the emission rates. A temperature-dependent pool algorithm with a constant β (0.09 °C−1 for monoterpenes and 0.143 °C−1 for sesquiterpenes) was used to normalize the measured emission data. For monoterpenes the emission potential varied between 0.5 and 18.5 μg gdw−1 h−1 and for sesquiterpenes between 0.02 and 0.4 μg gdw−1 h−1.