bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Sand Dynamic Elastic-Plastic Deformation Time-Dimensional Model
Authors: Chen Wen Hua , Li Meng , Song Qi
Published: November 2012

Dynamic shear characters of sands of Nanjing, Guangzhou, Harbin are studied, Some dynamic characters of schistose grain、shaft grain and round grain sand are compared and researched. The elastic-plastic change of structural sand skeleton under dynamic shear, the finally and irreversible deformation in the touched part of particle which maybe to produced elastic-plastic change deformation, the change of percent of mass different size particle, have been tested and he affection on dynamic shear from structures of schistose grain sand、staff grain and round grain sand and these affection to shear mould and extra-pore-pressure are analyzed. in order to simulate the nonlinear of dynamic volume and shear stress –shear strain during the liquefaction, a time-dimension-discrete model of sand diliatancy is suggested, the simplified equation can easy to explain the liquefaction and easily to analysis the dynamical deformations of soil.
A New Modulation Method Based on Current Hysteresis Control for Cascaded H-Bridge Inverter
Authors: Yang Min Sheng , Zhu Si Guo
Published: November 2012

This paper puts forward a current hysteresis control method suitable for cascaded H-bridge inverter. It has the following characteristics : The control method is similar to unipolar SPWM modulation for a single H bridge.It is simple for pulse generator and can effectively reduce the switching losses; The phase-shifted control pulse for multi H bridges of a phase with current hysteresis control can be generated which is similar to the phase shift SPWM by dynamically adjusting the width of hysteresis to keep power device switching frequency constant; It retains fast response, internal current limiting and with good stability for current hysteresis control.At last, the experimental results verify the correctness of the proposed method.
The Numerical Modeling of the Signal Transmission by the Cables and the Coil Coupling for LWD
Authors: Zhu Ke Bin , Nie Zai Ping , Sun Xiang Yang
Published: November 2012

Lack of efficiency in transmitting logging signals from down-hole to the top-hole server has long been one of the crucial problems for the development of LWD. This study aims to address this issue by exploring into the advanced scheme for LWD signal transmission proposed by NovatekTM. The main focus of the study is on electromagnetic coupling between two adjacent pipes. The coupler is modeled numerically by NMM efficiently according to the axial symmetry of the coupler. Through simulation and analysis which are based on the numerical model of the coupler, various parameters of the coupler are discussed, and some significant conclusions are obtained. The conclusions can guide optimization design of the coupler between the drill-pipes for signal transmission in LWD. Furthermore, the experimental results verify the good transmission performance of the coupler which is designed in this paper.
Optimization Design for Rotor Structure of Brushless Doubly Fed Machine
Authors: Wang Xiu Ping , Zhang Feng Ge , Zhu Xiao Ping , Jia Guang Long
Published: November 2012

Brushless doubly fed machine (BDFM) has rapid progress in recent years, rotor modulation capability is still the role factor which limits the popularization and application. Rotor structure is designed derived from the common reluctance in this paper, finite element analysis(FEA) is used for the optimization of the rotor. By studying the optimization comparatively, design program of rotor structure can be obtained, which shows great feasibility in industrial and agricultural production.
Analytical Calculation Model of Air-Gap Magnetic Field for Claw Pole Machine with Outer PM Rotor
Authors: Liu Guang Wei , Zhang Feng Ge , Gao Jin Xiang
Published: November 2012

In view of the time consuming and sensitive to finite element meshes, the finite element method is not suitable for claw pole machine with outer permanent magnet rotors with complicated and asymmetric 3D structure. A new analytical calculation model based on air-gap magnetic field analysis in polar coordinates is proposed. According to boundary conditions, the radial and tangential flux density is obtained by using the Fourier’s series, and then the cogging torque and no load EMF is calculated. In order to verify the accuracy of the analytical method, the finite element analysis is finished. Moreover, one prototype is manufactured and measured also. The analytical results well agree with those obtained by the FEM and experiments, confirmed the feasibility of this method.
On-Line Parameter Identification and Active Disturbance Rejection Control of Permanent Magnet Synchronous Motor
Authors: Wang Song , Li Guang Da
Published: November 2012

A new method named Windowed Least Square (WLS) to test main parameters of Permanent Magnet Synchronous Motor (PMSM) is proposed in this paper. Compared with Extended Kalman Filter (EKF) & Elman neural network and Recursive Least Square (RLS), WLS guarantees identification accuracy and excellent timeliness, and the issue of data saturation of RLS can be avoided. The PMSM model is built combining on-line parameter identification with Active Disturbance Rejection Control (ADRC) to improve the control performance of PMSM. The simulation results demonstrate that the performance of ADRC system using online estimation strategy is better than that of the system using PID method.
Vector Control for Connectionless Two-Motor Synchronous System
Authors: Zhang Jin Zhao
Published: November 2012

According to two three-phase asynchronous motors system running by connectionless-mode, and considering the system to be required to run in strict synchronous way under different load, the method of field-oriented vector control is used. Thus, the control loops of rotor flux, torque and rotor speed are constructed to make two-motor system run synchronously by torque distribution. The simulation results illustrate its effectiveness and good dynamic and static performance.
Comparison Research on Energy-Saving Search in Vector Control for Induction Motor
Authors: Wang Ai Yuan
Published: November 2012

The paper presents some search energy-saving algorithms and the latest research for induction motor. Based on the algorithms, the realization in vector control has been set up. The search time, current fluctuation, and final efficiency have been compared by a simulation case, which found the basis for further engineering application.
Density Functional Theory Study of GdnO3 (n=1-5) Clusters
Authors: Xu Lin , Liu Zong Lin , Yuan Hong Kuan
Published: November 2012

The geometries, stabilities, electronic and magnetic properties of small GdnO3(n=1-5) clusters have been systematically studied by using density functional theory with the generalized gradient approximation. We found that the Gd atoms and O atoms in GdnO3clusters prefer three and two coordination, respectively, which origin from the electronic configurations of Gd and O atoms. The results show that Gd2O3cluster is more stable than its respective neighbors, which is reflected from its high average binding energy and high HOMO-LUMO gap. In addition, we calculate the magnetic properties of GdnO3clusters. The local magnetic moments of the Gd atom in the GdnO3clusters exhibit a weak dependence on the O atoms, which are slightly enhanced with the increasing of the number of Gd atom.
Dynamic Simulation Analysis of Heavy Load Starting Light Load Running Induction Motor with High-Performance
Authors: Zhang Feng Ge , Xia Hong Yong
Published: November 2012

For the problem of heavy load starting induction motors in operation efficiency and power factor are low, a kind of heavy load starting light load running induction motor with high-performance is presented. In order to study the feasibility of this motor, the state equation of the motor is established and the dynamic simulation program of the motor is compiled. Finally, the program is simulated using software and the simulation result is analyzed.
Development of Marine Electrical Propulsion Simulator
Authors: Gao Hai Bo , Chen Hui , Lin Zhi Guo
Published: November 2012

The paper mainly introduces the idea of the design, system composition, and working principle of ‘Marine electrical propulsion simulator’. A fast start experiment is designed to obtain the data and curves from the small-scale simulator. A conclusion is drawn from the experiment that it is dangerous to set the propulsion motor at a high speed during the start period.
Application of Power-Line Power Frequency Communication in Oilfield Distribution Network
Authors: Zhang Chong , Lu Wen Bing , Zhang Liang , Chen Min
Published: November 2012

Because of the structure of oilfield distribution network and the demand of oilfield digital management, this paper designs a scheme which can realize parallel transmission of multichannel upstream signals according to orthogonal coding. The weak interaction between signals is proved through the platform. Meanwhile, we test in the same 6kV line of oilfield power network scene, and realize parallel transmission of 6 upstream signals. Thus, it creates favorable conditions for the transmission of greater capacity of oil monitoring information through the power frequency communication technology.
The Convergence Analysis of Parsing Algorithm in Power Flow
Authors: Jia Jun , Li Xuan , Han Ping Ping
Published: November 2012

Power flow solution is one of the most important means of power system stability analysis. While parsing algorithm is the basis of power flow analysis. The idea of iteration is frequently used in power flow solution because of the characteristics of power system itself. Textbooks, however, use the gradual iterative thought without rigorous demonstration of the conditions for convergence. From the point of view of mathematical analysis, the article not only gives a proper way to determine the convergence or divergence of the power flow but also provide the exact solution of a simple power flow with an example to demonstrate the validity of the algorithm.
Irradiation Distribution on Solar Cells inside CPCs with a Restricted Exit Angle
Authors: Yu Ya Mei , Tang Run Sheng , Xia Chao Feng
Published: November 2012

In this work, irradiation distribution on the base of ideal two-dimensional CPCs with and without a restricted exit angle, to which solar cells are attached, are analyzed by the ray-tracing technique. Results show that, given an acceptance half-angle (Θa), for CPCs without a restricted exit angle (CPC-1), radiation flux distribution on the base depends on the incidence angle of solar rays (Θ ); whereas for CPCs with a restricted exit angle (CPC-2), the flux distribution depends on and the restricted exit angle (Θe). For both CPC-1 and 2 with identical geometric concentration factor (Ct=2) and acceptance half-angle ( Θa=20), the peak flux concentration ratio on the base of CPC-2 with =65o decreases about 43%, 30% and 49% for the radiation at the incident angle of 0o, 10o and 18o, respectively, as compared to CPC-1. This implies that solar flux distribution on the base of CPC-2 is more uniform, thus, more efficient for photovoltaic conversion as compared with CPC-1.
Assessing the Ageing Condition and Lifetime of Electromagnetic Relay in Nuclear Power Plant
Authors: Shi Jie , Zeng Qi Quan
Published: November 2012

The Ageing mechanisms of electromagnetic relay were discussed. And the key ageing indicators were found out. Then, the test methods of ageing indicators were introduced. After that, a method to evaluate the lifetime for the coil of electromagnetic relay was proposed. Accelerated ageing test was conducted to the coils, and the key ageing indicators were collected periodically. According to those test data, the ageing condition and lifetime were evaluated. In the end of the paper, examples about assessing the ageing condition and lifetime were given separately.
Modeling and Design of Permanent Magnet Vibration-to-Electrical Power Generator’s Induction Coil
Authors: Wang Zhi Hua , Li Mei Ling , Zhang Jian , Wang Li , Xu Yong
Published: November 2012

The Equivalent Turn Number of Coil (ETNC) is proposed for induction coil design. Simulation results show that the vibrationonthe induction coil’s structure. The optimized coil is composed by two symmetry parts on the condition of sinusoidal vibration. The effective value of output EMF of optimized coil increases 51.39% than uniform coil’s. In the experiment, the optimized and uniform coils are fabricated with 600 turns and comparatively studied in the same vibration-to-electrical generator. The test results show that the peak-to-peak value and effective value of output EMF of the optimized coil can increase up to 52.59% and 48.76%, respectively, compared with the uniform coil.
Modeling and Simulation of Permanent Magnet Machines Output Voltage Conditioning in the Air Three Generator
Authors: Zhang Li Rong , Zhang Jing Zhou , Dong Guo , Ming Yang
Published: November 2012

The main role of the permanent magnet machine in the aviation frequency alternator is as the exciter. Its main function is not only to supply power for the generator controller but also supply the excitation current to exciter by supplying field winding of exciter with DC excitation voltage in the case without the emergency power. So we have to rectify 115V AC of permanent magnet machine output and make DC/DC conversion, so that the output is the suitable DC voltage. In the actual, it is very troublesome to make parameter tuning to rectifier module and DC/DC module, so this it is necessary to make model and simulation research. In this paper, we make module, simulation and parameter tuning for the rectifier and DC/DC transformation module in the MATLAB environment. From the simulation results, we can get that the model is correct, the parameters are appropriate.
Controlling Chaos in Power System Based on Tridiagonal Structure Matrix Stability Theory
Authors: Wang Hong Jun , Han Zhe Zhe , Zhao Hui Hui , Yue You Jun
Published: November 2012

In the case of periodic load disturbance, the chaos oscillation phenomena may caused by power system to threaten the safety operation of the network. In order to solve this problem, this paper presents the strategy on tridiagonal structure matrix stability theory. Using the designed controller, the chaotic system operation state turn into a stable operation state, and system is stabilized an unstable nonzero equilibrium point.
Research of Power System Harmonic Analysis Based on Wavelet Theory
Authors: Jin Tao , Gu Wen Jing
Published: November 2012

In recent years, the nonlinear load of the industry is increasing with the development of the power electronic technology. The harmonic distortion is getting more and more serious. So measurement, analysis, and restraining the harmonic of power system have become an important topic for the environmental management of the power system. This paper presented a novel method to analyze power harmonic using wavelet transform, and researched the technology how to detect and treat the harmonic in the power grid. The performance applying the wavelet method to detect harmonic from experimental signals was presented. The simulation results showed that wavelet transform can extract power harmonic in different frequency from the signal effectively.
A Simple Soft Sensing Method Based on DO Simulation for COD/OUR/Ammonia/Nitrite/Nitrate in a Constant Aerotion SBR
Authors: Zhu Ao , Wang Shu Ying , Peng Yong Zhen
Published: November 2012

Dissolved Oxygen (DO) is one of critical factors influencing substrate degradation and nitrification rates in activated sludge process. A two-step nitrification model describing the aeration period of the sequencing batch reactor (SBR) operation is developed. Parameter estimation of this model using the DO data determine the stoichiometry and kinetic parameters as well as the initial value of main nutrients, including readily biodegradable substrate, ammonia, nitrite and nitrate. Only if the parameter estimation is implemented, reaction related substrates can be predicted if new initial values are given. With optimal DO data, this paper pointed out that without initial value monitoring, both of the parameter estimation and prediction of the main nutrients profiles can be done through a simple method based on a global parameter estimation algorithm.
Research of Intelligent Integrated Averaging Pitot Tube Flowmeter
Authors: Ni Dan Dan , Sun Li Jun , Zhang Li Ming
Published: November 2012

Averaging Pitot tube flowmeter often uses a separated structure which is not convenient. The research uses a design of integration to overcome the problems and creates an intelligent system to process data. Some improvement methods such as the non-linear correction of meter factor, temperature and pressure compensation are proposed to improve the accuracy of flow rate. In experiments, by comparisons of the results before and after improvements, it comes to a conclusion that the intelligent integrated averaging Pitot tube flowmeter shows a higher performance.
A Ka-Band Bandpass Filterusing U-Shape Resonators Based on LTCC Technology
Authors: Liu Bing Yao , Zhou Jian Ming , Guo Ze Quan , Fu Jia Jun
Published: November 2012

This paper demonstrates a new Low Temperature Co-fired Ceramic (LTCC) U-shape resonator. Based on this 3D structure, a Ka-band Substrate Integrated Waveguidebandpass filter isdesigned. Compared with the conventional two dimensional PCB, LTCC technology achieveshigher Qe factor, higher density, smaller size, and lower cost. EM simulator HFSS is employed in determining and optimizingthephysical dimension of the filter.The filter's simulation results showfractional bandwidth (FBW) of3.94% centered at 34.7 GHzwith insertion loss of -1.2 dB and return loss of -20 dB in the passband. The attenuation of -30dB is obtained at 32.8 GHz and 36.8 GHz.
Design of DDS Based on Improved CORDIC Algorithm
Authors: Liu Zong Yao , Zhu Wei Hua , Qu Zhen Hua
Published: November 2012

For the shortcomings that computation speed of the DDS decreases with iterations increasing in CORDIC algorithm., the traditional algorithm of multiple iterations is displaced by a point of decompose predict the direction of rotation and multi-level iterative parallel computing method in this paper. The function simulation results show that the improved algorithm enhance the computation speed and maintain data high precision. This design has high computing speed, high precision and simple hardware implementation etc.
A Design of Loop Control Method for Feedforward Power Amplifier
Authors: Zhou Hua , Wang Lu Yu , Chang Wei
Published: November 2012

This letter delivered an analysis and design method of signal cancellation loop for feedforward power amplifier. To begin with the inherent defects of feedforward amplifier, it stated the merits and drawbacks of existing feedforward amplifier loop control methods, then put forward a new signal cancellation loop control method, namely separating amplitude feedback and phase feedback in signal cancellation loop, then advanced the theoretical analysis and calculation. The result of theoretical calculation was in line with the outcome of simulation, which confirmed through ADS (Advanced Design System) simulation. This method has multiple advantages: high feedback convergence rate, readily implementation and high linearity.
Optimization of Research on the Extraction of Humic Acid from Lignite Using Response Surface Methodology
Authors: Wang Pu Rong , Dai Hui Xin , Xu Guo Yin , Xu Bing Liang
Published: November 2012

Extraction of humic acid from lignite is an efficient method of comprehensive utilization of resource. Based on the trial test, the main factors such as extracting time, concentration of alkaline solution and extracting temperature, which were chosen as parameters to access their effects on extracting rate and identify the optimal conditions by using RSM. Box-behnken central composite design and advanced mathematics were applied to achieve the mathematical model that could predict the response (extraction rate). The results showed that the best technological conditions could be obtained， when extracting time was 82.32min, temperature was 65.83°C and the concentration of sodium hydroxide was 0.94mol/L. Prediction model showed that the maximum extracting rate was 89.19% and the actual experiment obtained a similar result.
Parameter Estimation of the Projectile In-Bore Based on Time-Frequency Analysis
Authors: Wang Li Mei , Wu Li , Meng Chun Xiang , Xu Feng , Peng Shu Sheng
Published: November 2012

Combined time-frequency peak filtering with wavelet modulus maxima, the millimeter wave interferometer echo signal process is presented, extracting the instantaneous frequency(IF) of the projectile in-bore. Based on that, the projectile’s velocity and acceleration curves are estimated and the length of the cannon is also calculated that’s consistent with the actual, which provides a strong basis for designing and improving weapons. And this approach ,with some commonality, can also be used to extract the IF of other signals.
Pattern Recognition of the Soft Abrasive Flow Based on Wavelet Packet
Authors: Hu Ke Dong , Ji Yi Xuan , Tan Da Peng
Published: November 2012

A Pattern Recognition method based on wavelet packet and artificial neural is proposed for solid-liquid two-phase flow characteristic parameters and the non-linear relationship between flow pattern. This method firstly established the physical and dynamic model, then set a monitoring point. To get the optimum wavelet tree and its information entropy, six floors of wavelet packet was used to decompose the collected velocity fluctuation signal. Transported the proper vector which is component by information entropy into Back Propagation neural network to train and identify. The recognition results show that this method can effectively overcome the subjectivity of traditional identification methods. It has good recognition effect, thus provide an effective choice for solid-liquid two-phase flow pattern recognition.
Research and Realization by FPGA of Turbo Codes
Authors: Xu Jin , Zhao Ying , Duan Shu Qiang
Published: November 2012

Turbo Code is a channel coding with excellent error-correcting performance in the condition of low noise-signal ratio.It has a superior decoding performance approaching the Shannon limit by adopting the random coding and decoding. This paper focuses on Turbo code and its implementation with FPGA and deeply analyzes the decoding theory and algorithm of Turbo code. Firstly, it analyzes the decoding theory of Turbo code. Then, it discusses key issues in the process of implementation with the most excellent and complicated Max—log—MAP algorithm. At last, it ends up with the Turbo encoder and decoding algorithm which hardware is successfully implemented finally.
Simple Transmission Performance Analysis System of Digital Signal Using FPGA
Authors: Zhang Xiao , Song Jie , Ding Hao
Published: November 2012

This article has designed a digital signal transmission performance analysis system using FPGA. It uses FPGA to generate the m-sequence whose frequency can be adjusted step by step and it uses Manchester encoding. Through the transmission channel, a fast bit synchronization detection arithmetic is used to abstract bit synchronization clock by FPGA. The oscilloscope can use the bit synchronization clock to observe eye diagram and other information. The system has the advantages of good transplant, small size, low-power consumption and high reliability.
Application of Wavelet Domain Adaptive Filtering to De-Noise NMR Data
Authors: Wu You Bin , Xie Ran Hong , Xiao Li Zhi
Published: November 2012

In this paper, the method of wavelet domain adaptive filtering was used to de-noise NMR echo data. Numerical simulation was used to compare the relationship between the SNR of NMR echo data and the results of T2 spectrum inversion before and after the de-noising procedure. The effectiveness of the wavelet domain adaptive filtering in the de-noising of NMR data was demonstrated. Compared with the traditional wavelet threshold de-noising, this adaptive de-noising method can obtain higher SNR results without the loss of useful signal.
A Variable-Length FFT Processor Base on Mixed-Radix Algorithm for PAPR Reduction in OFDM Systems
Authors: Meng Xiang Bin , Wang Jin Xiang , Yan Hai Long
Published: November 2012

An attractive technique of variable-length Fast Fourier transform (FFT) processor is proposed for PAPR reduction in orthogonal frequency division multiplexing (OFDM) systems. Mixed-radix algorithm and single path delay feedback (SDF) pipeline architecture is adopted to obtain low computation complexity and preferable flexibility for its VLSI implementation. The FFT processor can be reconfigured as 512, 1024, 2048, 4096-points, moreover, the only one RAM unit is used for store sine/cosine tables. The chip is mapped to the 0.18 CMOS technology and the core area is 7.896mm2. The experiment results show that the proposed FFT processor is suitable for PAPR reduction in OFDM communication systems.
Harmonic Calculation of 12-Pulse Rectifier and Determination of Filter Capacity
Authors: Li Yang , Yu Yong Jun
Published: November 2012

In order to enable engineers to assess the impact of harmonic currents produced by the 12-pulse rectifier unit on the grid. In this paper, through experimental and theoretical reasoning, I discusses in detail the harmonic calculation parameters required of rectifier unit and calculate the filter capacity which reached the filtering standards for single-tuned filter capacitor. Through this method, we can make a good assessment of the harmonics generated by the project and propose effective control measures for the harmonic excess in the beginning of the project construction.
Recognition and Diagnosis of the Incipient Faults in Analog Circuit Using Improved HMM
Authors: Zhang Ji Jun , Ma Deng Wu , Wang Lin
Published: November 2012

Due to the uncertainties that exist in the running of the analog circuits, the traditional hidden Markov model (HMM) approach is improved through replacing the state transition probability (STP) matrix of the traditional model by time-varying one. An updating control factor is introduced for avoiding the excess updating of the STP in the initial stage of each state. The experimental results indicate that the improved HMM has better fault recognition and diagnosis capability.
Using Ambient Noise to Inverse Geo-Acoustic Parameters
Authors: Meng Chun Xia , Li Gui Juan , Zhang Liang
Published: November 2012

This paper presents a theoretical study of the vertical coherence of ocean ambient noise as the source is the windy ocean surface on the ray theory. At low frequencies less than 2 kHz, the sensitivity of stratified fluid seabed to the vertical coherence of ambient noise in shallow water is analyzed under the condition of distance-irrespective stratified ocean. Using ambient noise data from Chinese north shallow water seabed geo-acoustics parameters are obtained, and the research results show that the inverted method is effective.
A Waveguide Design of Microwave High Power Passive Tuner
Authors: Sun Lu , Zhan Jin Song , Wang Jia Li
Published: November 2012

Passive tuner is the core component of high-power load pull measurement system. To overcome the leakage of electromagnetic field to the outer space and decrease the insertion loss, a structure of waveguide and diaphragm with the choke structure is adopted to design the 25-40GHz tuner. The simulation results of HFSS (High Frequency Simulator Structure) software show that the structure can meet the requirements of the tuning ratio and decrease the insertion loss, and it can be used in the load and source pull measurement system successfully.
An Improved ip-iq Harmonic Detection Algorithm
Authors: Cui Xue Hai
Published: November 2012

This paper introduces the the basic principle of ip-iq harmonic detection algorithm and puts forward a method of harmonic detection for the single-phase circuit. This method eliminates the three-phase to two-phase and two-phase to the three-phase coordinate transformation, thus effectively reduces the computation ; moreover it has the advantages of good real-time performance and makes the digital control easy. Matlab simulation results show that this method can detect the harmonic component of single-phase and three-phase current accurately and in real-time.
A 10Gb/s Low-Power Front-End Amplifier for Optical Receiver in 0.18μm CMOS Technology
Authors: Lei Zhu , Chen Ying Mei , Tian Ling , Zhang Li
Published: November 2012

A Front-End Amplifier for the STM-64(10Gb/s) optical receiver in SDH system has been proposed in TSMC 0.18 μm CMOS technology. The common-gate feedforward configuration with an active inductor is employed in the input stage of transimpedance amplifier to increase the bandwidth. A 3-order interleaving active feedback configuration is employed to expand the bandwidth in the gain stage of transimpedance amplifier and limiting amplifier. Simulation results show that the output swing is 190mV (Vpp) when the input current varies from 20μA to 400μA. The power consumption is only 98.2mW with 1.8V power supply and the chip area is 496μm×480μm.
A High Efficiency Step-Up WLED Driver with Wide Range PWM Dimming
Authors: Xu Fei , He Le Nian
Published: November 2012

A high efficiency step-up White Light Emitting-diode (WLED) driver with PWM dimming is presented in this paper. An integrated current sensing technique is used to improve system efficiency. Meanwhile, a novel PWM(pulse width modulation) dimming scheme is proposed to achieve wide range dimming frequency, which can be adaptive to dimming frequency from 200Hz to 200 KHz. The proposed driver is designed with CSMC 0.5um 40V bipolar-CMOS-DMOS process. Simulation results verify the functionality of the design and high efficiency is realized, with a peak value of 94.12% at 5.5V-input and 200mA-load.
Data Quality Control of Wind Profiler Radar Based on Extended Kalman Filter
Authors: Li Jia Qiang , Chen Xing Juan , Chen Jin Li
Published: November 2012

As a new type of Doppler wind radar, Wind profiler radar often suffers from a variety of meteorological factors. These interferences have great effect on the detection data precision, which leads to radar data quality problem. A data processing method based on Extended Kalman Filter (EKF) is presented in this paper, which focuses on the nonlinear problems of wind data of wind profiler radar. This method is the development of traditional Kalman Filter (KF) in practical engineering applications. To verify the validity of this first-order EKF from different situation, one day’s and one moment’s wind data are selected respectively, as examples for filtering. EKF is better for data processing of wind profiler radar and has some engineering application prospects.
Design of Micro-Wideband Radar Experiment System
Authors: Yin Ya Fang , Duan Long Hui , Liao Yan Na
Published: November 2012

This paper presents a micro-wideband radar experimental system design. Wideband signal source and high-speed data sampling and processing module of the system is discussed in detail. Designed radar experimental system weighs 4.5Kg, with signal bandwidth of 1GHz and effective distance of 5km. The system can realize wideband radar echo real-time sampling and processing functions. On-board Synthetic Aperture Radar (SAR) imaging experiment is done. The imaging resolution of the system is 0.3m, this result is satisfactory. It shows that the system can meet the requirements of a unmanned aerial vehicles (UAV) platform. The design and test results are significant to miniaturization of wideband radar system.
Test Frequency-Domain Parameters of ADCs Using a Spectrum Leakage Correction Algorithm
Authors: Yin Shi Rong
Published: November 2012

This paper analyzed the principle of the interpolation algorithm and the cause of spectrum leakage, derived an interpolation formulas of estimation the incoherent degree to correct the spectrum. Polynomial approximation method is used to get the correction formulas. Simulate results demonstrate that the correction Algorithm can reduced the spectral leakage and increase ADC parameters calculation accuracy.
A Study on the System of Radio Frequency Identification and Localization Works in UHF
Authors: Pan Yong , Liu Kai Hua , Gao Yi , Zhao Rui
Published: November 2012

This paper designs a hand-held radio frequency identification and localization terminal based on ARM Cortex-M3 processor and active radio frequency tags based on 8051 processor. This terminal uses STM32F103VET6 as its master controller, these tags use STC12C2052AD as their master controller. They all use Nordic nRF905 as their radio frequency identification module. The system works in 433M/868M/915MHz ISM UHF band and can read, write and locate radio frequency tags within 50m indoors. The actual measurement of active radio frequency tags shows that this terminal is highly stable and comparable in 433M/868M/915M ultra-high frequency radio identification and localization. The test results of this system are also analyzed and presented.
Design and Simulation of LED Drive Power Supply Based on ARM
Authors: Cheng Hong Li , Ren Xiao Dan , Sun Shuai
Published: November 2012

This paper introduces a kind of numerical controlled LED drive power supply based on ARM7. User can set the number and brightness of the LEDs to be lit by the remote control. Switching voltage source and the linear constant current source are connected in series, this circuit structure can ensure high efficiency and small current ripple. ARM7 completes the data collection, fuzzy PID algorithm processing, and real-time output adjustment. This paper explains the working principle of the system in detail and then simulates it in the simulink. The results show that it can satisfy the users' diverse requirements well and give full play to the convenience and controllability of the digital controller.
Micro Experimental Research on Cement Stone under Sulfate Erosion
Authors: Zhu Jue , Chen Qian , Ding Yuan Yuan
Published: November 2012

In this article, micro investigation of the cement stone under sulfate erosion is carried out by using SEM (Scanning Electron Microscope). The XRD method is also employed to semi-quantitatively analyze the erosion product. The cement stones whose water-cement is 0.45, 0.55, 0.65, respectively, immersed in sulfate solution whose sulfate ion concentrations is 0%, 3%, 4%, 5%, 6%. After different immersion time of 24 days, 45 days and 60 days, the microstructure of samples is detect by the SEM. The energy-dispersive X-ray analysis (EDX) is taken to determine the general elements in samples. The XRD method is employed to semi-quantitatively determine the weight percents of ettringite and gypsum in cement stone samples. Through comparative analysis, it tries to point out how the sulfate ion and water-cement ratio will affect the erosion products.
The Design of Wireless Monitoring System Based on Zigbee
Authors: Gong Wen Chao , Zhou Zhi Yong , Wu Meng Meng
Published: November 2012

In recent years, the secret place’s frequency occurrence of leaks has brought huge economic losses on the national security、 social stability and economic life, which not only seriously harmed the national interest, but also raised a range of negative social impacts. Therefore, implementing effective monitoring strategies to protect the secret place is of great significance. In the paper, the wireless short-range communication technology ZigBee was adapted to design a wireless monitoring system, the short-range communication technology ZigBee can network quickly and has many monitoring terminals, so it can monitor the equipments and materials, persons and the environment in the building and protect the security of buildings from the source.
Remote Monitoring System Design for Renewable Energy Connected to Power Grid System
Authors: Zhang Li Jing , Xiong Wei , Xian Xue Hui
Published: November 2012

Distributed generation technologies, basically about renewable energy, develop rapidly, and how to implement remote concentrated monitoring, management and scheduling on grid connected generation is the key problem in promoting renewable energy generation. The design of remote monitoring system for renewable energy generation grid connected, based on GPRS-Internet, has the functions of data acquisition, monitoring control, grid interconnection detection control, information management and so on, as well as the integration of meteorological information and geological information, which can better adapt to the features of wide distribution and scattered allocation of renewable energy generation, bringing a more safe and effective monitoring management.
Effect of Fe3O4 on the Bioactivity of Immobilized Cells of Monascus purpureus
Authors: Zhang Feng Qin , Li Tao Tao , Li Xiao Long
Published: November 2012

Fe3O4/chitosan composite was developed as a new type of cell carrier to be used in red pigment fermentation. The presence of the Fe3O4 particles in chitosan composite not only improved the yield of red pigment, but also enhanced the biomass attached on the composite. The Fe3O4/chitosan composite was found to be more effective for immobilization of Monascus purpureus than chitosan particles. Red pigment of 2.24 UA510 was obtained using Fe3O4/chitosan composite cultures in liquid fermentation. The biomass attached on Fe3O4/chitosan composite reached to 264 mg dry wt. cells/g carrier.
Influence of Machining Parameters on Diameter Error in Drilling of GFRP – Armour Steel Sandwich Composites
Authors: Bosco M.A.J , Palanikumar K. , Prasad B. Durga , Velayudham A.
Published: November 2012

This paper presents a study on cutting parameters on the roundness error on drilling of an armour steel –Glass fiber reinforced plastic sandwiched plate, which is extensively used in defence industries. The influence of parameters on roundness error is presented in detail. The results indicated that the increase of feed rate increases the roundness error, whereas the increase of spindle speed reduce the roundness error in drilling. The results are analysed through graphs and presented in this study.
Glass Transition in Quantum Dipole Glass Model
Authors: Busiello G.
Published: November 2012

We give a description of the phase transition in an ensemble of the electric dipole with internal degrees of freedom in dielectric glass model.The model predicts a freezing of the random projections of the electric dipole moments. The low temperature phase transition from disordered paraelectric phase to the electric dipole orientational like glass phase is considered
Nonlinear Prediction Control of Synchronous Generator Excitation Based on Subsection Approximation
Authors: Zhao Hong Shan , Lan Xiao Ming , Zhao Yu Si , Xia Yang
Published: November 2012

This paper presents a subsection approximate nonlinear model predictive control (SANMPC) method for synchronous generator excitation control in the regional power grid. The proposed SANMPC considers the voltage as the reference trajectories and the change range of active power, reactive power and voltage as unequal constraints. Segmenting for a sampling interval, it uses sampled values and the control input initial value at the current sampling moment to predict the state at each segment by the Explicit Euler method. The predictive equations of the next sampling moment can be obtained by the predictive state and the control input at the penultimate segment, and form the optimal control problem which may be solved by the interior-point method. We take advantage of a four-machine power system to verify the effectiveness of the proposed SANMPC method under MATLAB platform. The simulating results show that the SANMPC method is simple and efficient, and greatly improves the transient stability compared with the conventional controller both.
Submersible Motor Vector Control System Simulation Based on SVPWM
Authors: Wen Jia Bin , Wang Xiao Qi
Published: November 2012

In this paper SVPWM （Space vector pulse width modulate）inverter model was built with the Matlab/Simulink based on the principle of SVPWM. Then based on that built the models of submersible motor’s control system which is supplied by SVPWM-inverter．Finally, ran the simulation and gave the results.
Integration of Power System Real-Time Digital Simulator and Optimal Power Flow
Authors: Chen Meng Jen , Wu Yu Chi , Chen Wen Shiush , Huang Pei Wei , Tsai Tsung Wei
Published: November 2012

In this paper, a framework for integrating a real-time digital simulator and EMS-OPF program is proposed and addressed, through two different communication architectures: asynchronous and synchronous. Validation of these communication architectures is carried out by Ethernet UDP/IP (asynchronous) and analog channels of IO card (synchronous). With this framework, both dynamic and steady-state performance of a power system can be studied easily in real-time mode.
Research on Fine and Deep Holes of Pulse Electrochemical Finishing
Authors: Zhai Xiao Bing
Published: November 2012

Top-quality surfaces are obtained by means of pulse electrochemical finishing (PECF) in neutral electrolyte. The rules of effect of main experimental parameters such as pulse current density, electrolyte flow rate and interelectrode gap on surface quality are analyzed based on the experiments in detail. Moreover, the technique are applied to some typical cases such as surface finishing of fine and deep holes that is more difficult to be machined by the traditional finishing technologies. The results show mirror-like surfaces could be gained by PECF and the surface roughness values could be reduced from more than Ra 1.6μm to less than Ra 0.08μm within several seconds. The experiments show that PECF will play an important role in finishing key parts that is more difficult to be machined by the traditional finishing technologies in the modern manufacturing industries.
Numerical Simulation of Temperature Rise of a Direct-Driven Axial Flux Permanent Magnet Wheel Motor with Experimental Verification
Authors: Sun Wei , Fan Tao , Wen Xu Hui
Published: November 2012

To evaluate the thermal behavior of a direct-driven axial flux permanent magnet wheel motor, a simplified equivalent model of windings was proposed， which can also be applied to assembling air gaps between components. The temperature rise of a direct-driven axial flux permanent Magnet wheel motor was calculated and analyzed using the equivalent model. The results show that the equivalent model simplifies the temperature calculation of motors, and the accuracy of the proposed model is verified by prototype machine tests.
Research on Tension Control of Winding Systems Using Electronic CAM
Authors: Peng Bi , Gong Shi Hua , Huang Yu , Liu Yi Lin , Zhang Shang
Published: November 2012

Tension control is a crucial technology for winding control. In the present work, a theoretical analysis and design of tension control used in the winding systems for lithium-ion battery is proposed. Through analyzing the winding process of battery batteries, a speed control curve of the winding motor is designed, with which we can achieve a constant-linear-speed operation of the pole-pieces. Based on the electronic CAM technology, using the approximation method, the constant-linear-speed control curve is obtained. Experimental work is done to study the actual evolution curve of speed for battery pole-pieces. Experimental results show that the rate of speed fluctuation between the maximum speed and the minimum speed reduces from about 10 times to 2 times. It confirms the effectiveness of the application of electronic CAM control strategy in tension control.
Control Model of Vehicle Turning Stability Based on Neural Network
Authors: Men Yu Zhuo , Yu Hai Bo , Pan Xin , Li Yue Wei , Huo Na
Published: November 2012

In order to research the turning stability of a semi-active suspension vehicle, the suspension damping BP (Back Propagation) neutral network PID (Proportion–Integral–Differential) control technique was proposed. The ideal and actual yaw rate error is taken as the control targets to carry on the turning stability closed-loop control. The vehicle yaw rate is controlled to analyze the impacts of the suspension damping change on the wheel vertical load and roll. The MATLAB software was applied to carry out simulation according to the single lane steering and step turning working conditions. The results show that the suspension damping can be controlled to control the vehicle yaw and cornering motions in the process of the vehicle turning on the high adhesion road. When the front suspension damping is increased and the rear suspension damping is decreased synchronously, the load transfer of the left and right wheels of the front and rear axles is obviously decreased, thus being able to effectively restrain the over-steering behavior of the vehicle.
Numerical Analysis on Aerodynamic Characteristics of Truck
Authors: Bao Hai Tao
Published: November 2012

Computational Fluid Dynamics (CFD) is used for the investigation of the aerodynamic characteristics of the truck. The gap between the truck and the container of the heavy truck on its aerodynamic characteristics were simulated by using equations and dynamic mesh method. The finite volume method is used to discrete the governing equations, the second-order up wind difference scheme is adopted for the convection term and the centric difference scheme for the dissipation term. The discretion of time is carried out by a full-implicit time integral scheme. Analysis of the simulated flow fields and the change pattern of the aerodynamic drag under different gap length demonstrate that when the gap length change and the aerodynamic characteristics change. This paper provides a theoretical reference for the development of truck products determining the gap distance between the truck and the container.
Finite Element Analysis of Drive Axle Housing of a Special Vehicle
Authors: Ma Cong Bing , Wu Yong Hai
Published: November 2012

The integral axle housing of a special vehicle was taken as the research object, with the 3D model of the drive axle housing built by using 3D CAD software UG. The ANSYS is taken as the FEA computing platform, the strength and stiffness of the axle housing under the five load conditions is calculated by it. The results show that the impact of such conditions, the drive axle housing can happen to be yield easily. While in the remaining conditions, the drive axle housing is not too much security reserves, which exit some certain security risks. The method used in this paper for great guiding significance to reduce product development costs, shorten development cycles and improve product quality.
Optimize Design of a Light Truck Frame
Authors: Ma Cong Bing , Wu Yong Hai
Published: November 2012

In this paper the basic structure of frame is optimized through homogenization method in the basic frame structure loaded with bending conditions under the conditions that ANSYS is regarded as the optimal design platform, the flexibility of frame is taken as the objective function and the volume is used as a constraint The optimization topology structure of the frame is obtained which meets the volume constraints and total compliance smallest. Using the ANSYS software calculates and verifies the security of frame structural strength under the fully loaded bending condition. Model and optimization methods used in this paper also can apply to other types of optimization design of the frame, and provides a useful reference for the optimized design of the similar structure.
Hydrostatic-Hydrodynamic Bearing Design of High-Speed Camshaft Grinding
Authors: Huang Yu , Zhang Shang , Liu Yi Lin , Peng Bi , Zhang Guo Jun
Published: November 2012

Conditions for changing acceleration and force spindle when the high-speed high-precision camshaft grinding with the action of follow grinding and the constant linear speed grinding，a step-pocket cavity hydrostatic -hydrodynamic bearings is designed to meet this precision camshaft grinding, and the relationship between eccentricity and bearing stiffness, load are analyzed by the method of finite-element analysis with fluid finite element analysis software.