Table of Content

15 August 2010 Volume 23 Issue 8

  

Articles

Three-dimensional Models of and Algorithms for Micro-manufacture Simulations

XU Dong-Liang, ZHANG Jian, XU Xiao-Lin

. 2010, 23(8):  1. 

Abstract ( 1081 )   PDF (1563KB) ( 798 )  

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Micro-manufacture develops MEMS technology in the recent decade.In this manufacture,3D topography simulations are important to designing the fabrications and devices of MEMS.New developments of models of and algorithms for three-dimensional topography simulation in recent years are introduced and compared,with some simulated samples enumerated.

DDRⅡ Simulation Design Based on Cadence

ZHAO Hai-Shun, WANG Zhi-Ping, JI Xiao-Yan

. 2010, 23(8):  5. 

Abstract ( 1646 )   PDF (1010KB) ( 1109 )  

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Aiming at the problem of high-speed signal integrity and timing mach in the DDRⅡ design,this paper presents the simulation design of PCB which includes DDRⅡ memory through the use of Cadence software.Cadence software is adopted to make topology of DDRⅡ signals and to get the parameters related to signal integrity,such as crosstalk,ISI,overshoot and so on.The parameters related to timing sequence of DDRⅡ signals can be obtained from the simulation waveform,and thereby the timing budget for DDRⅡ signals can be calculated to make constraints for them for the layout.After the layout,the post-route simulation is done in order to identify the signal integrity and timing sequence of the DDRⅡ signals.Some design guidelines are summarized based on the simulation results.

A Fast Active Scanning Algorithm for IEEE 802.11 Handoff

YANG Wei-Dong, LIU Ji-Zhao

. 2010, 23(8):  9. 

Abstract ( 1078 )   PDF (857KB) ( 900 )  

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A fast active scanning algorithm is proposed for IEEE 802.11 handoff.Firstly,the STA select the scanned APs from neighbor AP graph with location information;Second,the STA begin to probe the APs using uni-cast way.The algorithm reduces the delay which is brought by wasted channels,waited time and collisions.Simulation shows that the algorithm not only finishes the handoff but also reduces remarkably the latency.

Study of Radar Target Range Profile Feature Extraction

ZHAO Peng-Liang, GAN Huai-Jin, ZENG Hai-Bing

. 2010, 23(8):  12. 

Abstract ( 1774 )   PDF (495KB) ( 838 )  

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Based on the undamped exponential model of radar target range profile,the genetic algorithm and Relax algorithm are used to extract the parameters of scattering centers.The simulation results show that the method is feasible.

An Improved Algorithm for the Arithmetic Encoder in JPEG2000 and its Implementation

XIE Hui, WANG Jiao, XU Lei

. 2010, 23(8):  15. 

Abstract ( 1403 )   PDF (619KB) ( 1088 )  

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As a new still image compression standard,JPEG2000 has many advantages,such as higher compression rate and multi-resolution format.JPEG2000 coding is embedded block coding with optimized truncation (EBCOT),and the process of code adopts the MQ arithmetic coding.This paper analyzes the deficiency of MQ arithmetic coder in coding the image with single content and less information,and proposes an improved algorithm of the MQ arithmetic coder to improve the PSNR of coding the simple images and the quality of the decoded images.

Research on and Simulation of A CCD Image Sensor with a Vertical Anti-blooming Structure

WU Li-Fan

. 2010, 23(8):  18. 

Abstract ( 1321 )   PDF (735KB) ( 952 )  

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By using MEDICI,A CCD device simulation structure with vertical anti-blooming is calculated numerically to eliminate blooming and smear in the CCD image sensor in its exposure to intense sunlight.The effect of the 1PW impurity concentration parameter on the vertical anti-blooming ability of CCD is analyzed and the vertical anti-blooming structure of CCD is optimized.The electronic shutter is developed by the work principle of vertical anti-blooming.

A Method for Simulating the Dynamic IR Image of Smoke

ZHANG Tao, HUANG Xi

. 2010, 23(8):  20. 

Abstract ( 1114 )   PDF (995KB) ( 1047 )  

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The extinction model,dispersion model and temperature attenuation model are established through the analysis of the theory of smoke obscuring the target.A dynamic IR image of smoke is simulated by calculating smoke's surface radiation in different states in real time.The effect of wind,gravity and other factors on smoke is initially realized,which will improve the fidelity of smoke's IR simulation.

Research on Balanced Optical Heterodyne Detection and Local Laser Intensity Noise Suppression

HE Ji-Ke, ZENG Xiao-Dong

. 2010, 23(8):  25. 

Abstract ( 1371 )   PDF (1063KB) ( 1148 )  

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The origin and characteristics of LD pumped continuous-wave solid-state laser intensity noise and balanced optical heterodyne detection are introduced.The influence of amplitude mismatching and relative propagation time delay which exist in the two arms of balanced photodetector(BPD) on signal detection and noise suppression is closely analyzed.Finally,a numerical result is presented and it shows that rigid propagation time delay must be controlled to suppress wide-band noise and for a BPD with f^{_{-3 dB}}=884 MHz a relative time delay less than 55.3 ps must be guaranteed to suppress wide-band noise for 30 dB at least.

Determination of Temperature Field Distribution of Frequency Doubling Crystal by the Mirror Method

LV Juan, GUO Zhen, WANG Shi-Yu

. 2010, 23(8):  32. 

Abstract ( 1331 )   PDF (1301KB) ( 893 )  

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A thermal distribution model is established based on the analysis of the KTP crystal.Mirror method can be used to solve boundary value problem of steady temperature field.This model agrees well with practical situation with good precision,having an instructional significance for improving the performance of frequency double laser.

Analysis of the Accelerated Life Test of He-Ne Laser with Circular Cavity

LU Chang-Mou, SHI Shun-Xiang, LIU Ji-Fang

. 2010, 23(8):  37. 

Abstract ( 1441 )   PDF (528KB) ( 895 )  

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In order to find the theory model and lifetime test method of life estimate of He-Ne laser with circular cavity under specific conditions of use,it is assumed in this paper that the lifetime distribution of He-Ne laser with circular cavity work at high electric current obeys Weibull distribution,accelerating life test of the He-Ne laser carried on increasing electric current as acceleration stress.Least-square method is used to process the test data.The results shows that the assumption is correct and the characteristic life of He-Ne laser with circular cavity working at normal electric current can be calculated through that at high electric current,effectively reducing the time of the test.

Determination of Trace Metal Impurities in Solar Grade Polysilicon by ICP-MS

LIU Zhi-Juan, CHU Lian-Qing, HE Xiu-Kun, CAO Quan-Xi

. 2010, 23(8):  40. 

Abstract ( 1634 )   PDF (504KB) ( 883 )  

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This paper describes the method for the determination of trace Al、Fe、Ca、Mg、Cu、Zn、Cr、Ni and Mn in solar grade polysilicon by inductively coupled plasma mass spectrometry.The mass spectral interference and the matrix effect are discussed.Sc and Rh are used as internal standard to corrected the interference due to the effects of matrix and interface efficiently.Under the optimum conditions the detection limits for impurities were in the range of 0.030 g/L～0.500 g/L.The recoveries were within 90.0%～107.1% and  relative standard deviation within 0.9%～3.4%.

Simulation and Optimization of Current Distribution in GaN-based LEDs

LIU Yi, ZHAO Guang-Cai, LI Pei-Xian

. 2010, 23(8):  43. 

Abstract ( 1583 )   PDF (1887KB) ( 1310 )  

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Electrical properties of a LED (light emitting diode) is simulated with the software of SILVACO,by using two-dimensional finite element method.The current distributions of three LEDs of different size are compared,and the relationship between the current density and L is found,which indicates that current uniformity can be improved by reducing the current expansion length(L).Five different kinds of power LEDs with a chip size of 1 mm×1 mm and with different electrode structures are simulated and compared,and the optimal electrode structure is found.

Effects of La₂O₃ and Nb₂O₅ Doping on Sensitivity and Semi-conductivities of SrTiO₃

DU Li, CAO Quan-Xi

. 2010, 23(8):  47. 

Abstract ( 1270 )   PDF (1052KB) ( 980 )  

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The Effects of La₂O₃ and Nb₂O₅ doping on the sensitivity and semi-conductivities of SrTiO₃ oxygen sensors are investigated.Semiconductor SrTiO₃-based oxygen sensors are prepared by solid phase synthesis at 1 220 ℃.Effects on sensitivity and resistance of different La and Nb doping proportion are discussed.The results show that double donors doping proportion not only promotes the semi-conductivity but also strongly influences sensitivity of SrTiO₃ oxygen sensors.SrTiO₃ exhibits excellent sensitivity to oxygen when the doping proportion is 0.03.

Computer Electromagnetic Radiation and its Protection

LIU Xi-Jie, LI Ping, LIU Ying

. 2010, 23(8):  50. 

Abstract ( 1720 )   PDF (615KB) ( 1118 )  

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In view of the computer electromagnetic information leakage of information security implication,this paper analyses the time-frequency characteristics of radiation signal from LCD display with a resolution of 1 280×1 024 through simulation.The design and measurement of the shielding box is given.A USA military standard testing is made,which shows that the designed electronic shielding box is less than the overall emission of radiation 35 dBμV/m,and with a proper increase in protection radius,the amount of its radiation emission can be reduced to 20 dBμV/m or less,lower than the 20 dBμV/m of the ambient noise thus meeting the information security requirements.

Study on Left-hand Material with Dual Left-handed Bands Based on the Structure of Microstrip Line

GONG Hao, YU Ying, ZHANG Ya-Nan

. 2010, 23(8):  53. 

Abstract ( 1169 )   PDF (531KB) ( 1205 )  

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A novel composite right/left-handed transmission line (CRLH-TL) meta-material with two left-handed bands based on the structure of microstrip line is proposed.The topology and method of operation of the line are discussed.The two pass bands of the CRLH-TL exist at 2.5 GHz and 6 GHz respectively.S₁₁ and S₂₁ can be achieved through simulation which validates the existence of Left-handed chrematistics.A CRLH-TL with two main pass bands would play an important part in a number of quad-band applications.

A High Precision Bandgap Reference

DUAN Wen-Yong, HE Xiao-Xiong

. 2010, 23(8):  55. 

Abstract ( 1255 )   PDF (480KB) ( 1172 )  

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The bandgap reference circuit in analog and mixed-circuit system is a very important module.A high-precision bandgap reference tube is designed in this paper.On the basis of conventional positive temperature coefficient current,the resistance of two different materials is added to achieve the benchmark second-order band-gap temperature compensation.The use of folding with feedback bias cascade op-amp in band-gap reference circuit achieves a very high accuracy and temperature stability.

Principles of Polyphase Filtering for Digital Quadrature Detection and its Realization on FPGA

HE Guang-Ming, HUANG Yun

. 2010, 23(8):  58. 

Abstract ( 1142 )   PDF (774KB) ( 1282 )  

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Pholyphase filtering is one of the key technology to implement digital down conversion and quadrature coherent detection,which can provide high fidelity quadrature signal for digital signal processing of radar,sonar,communication and other systems.The basic principles of polyphase filtering are discussed.The results of computer simulation of Band-Limited IF signal processing based on polyphase filtering is given.It is validated by the implementation project of wideband digitized receiver on pulse compression radar.

The Design and Implementation of the Fourth-order Chebyshev Active Filter

WANG Hao-De, SHI Lin

. 2010, 23(8):  62. 

Abstract ( 1544 )   PDF (697KB) ( 968 )  

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A new fourth-order Chebyshev active filter is presented and simulated using Pspice.The simulation results show that the fourth-order Chebyshev active filter has a high operating stability.

Bandpass Filter with Two Transmission Zeros Using LTCC Technology

DING Shi-Min, TIAN Hui

. 2010, 23(8):  65. 

Abstract ( 1278 )   PDF (588KB) ( 931 )  

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Based on LTCC technology,this study proposed a second-order bandpass filter,which is often used as a important part of passive components.As for the design of filters,it is a common microwave band-pass filter with the centre frequency of 2.45 GHz and bandwidth of 100 MHz,while the transmission zeros frequencies are 1.75 GHz and 4.40 with a size of 3 mm×3 mm×0.7 mm.This filter consists of six layers of capacitors and inductors.The perfect agreement of electromagnetic simulation with circuit simulation indicates good working mechanism both in miniaturization and frequency performance.

Design of Microwave Power Amplifier Based on Small-signal S Parameters

QI Yun-Fei

. 2010, 23(8):  68. 

Abstract ( 1364 )   PDF (528KB) ( 1350 )  

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A power amplifier designing method based on small-signal S parameters and the static I-V curve is presented.Firstly,by means of the ADS software,the small-signal S parameters of the power amplifier are utilized to make the file of S2P for the use of the simulation circuits.Secondly,the model of input and the output matched circuits in ADS software is built to optimize the input and the output circuits according to the maximization gain by using the optimization function in the software.Finally,the whole circuit is optimized to complete the design of the circuits.

Narrow-Band Interference Rejection Method Based on the Transform Domain Communication Technique for the OFDM System

GUO Li-Li, YUAN Bo

. 2010, 23(8):  70. 

Abstract ( 1491 )   PDF (544KB) ( 869 )  

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In order to solve the problem of interference by narrow-band signals in the wideband OFDM system,a method based on the TDC technique is proposed for NBI rejection in the OFDM system.The optimal OFDM signals based on the estimated spectrum is designed to suppress the NBI in the TD.This method not only effectively reduces the impact caused by strong NBI,but also enables the SNR to be less susceptible to the effects of transform domain filtering.The simulation results in the AWGN channel show that this method based on the TDC technique can effectively suppress the NBI in the wideband OFDM system.

Analysis of Spread Spectrum Performance of the OFDM System

WANG Hui-Qiu

. 2010, 23(8):  73. 

Abstract ( 1524 )   PDF (466KB) ( 935 )  

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The spread spectrum property obscuring in traditional OFDM system is presented.By decreased subcarriers using in OFDM system,the spread spectrum property in OFDM system is discovered.The spread spectrum performance in OFDM system is analyzed using of traditonal spread spectrum systems theory.It is shown that the OFDM system has as good a spread spectrum performance as traditional spread spectrum systems,and can be used to build spread sprectrum systems.

Study on Heterdyne Detection of Synthetic Aperture Radar

ZHAO Xiao-Yan, YANG Yang

. 2010, 23(8):  75. 

Abstract ( 1107 )   PDF (638KB) ( 1031 )  

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Heterodyne detection is adopted by all existing synthetic aperture radars for its advantages,but in practice,match between the signal beam and local-oscillator beam is difficult to realize.This paper analyzes the effect of the angle between signal beam and local-oscillator beam on the heterodyne signal.

USB Interface Design Based on Blackfin532 and Netchip2272

DU Meng-Meng, REN Bai-Ling, DONG Chun-Xi

. 2010, 23(8):  77. 

Abstract ( 1748 )   PDF (633KB) ( 885 )  

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A USB interface design using Blackfin532 and Netchip2272 is presented with the advantages of simple hardware interface circuit and good firmware transplantablilty.The principle of the design is illustrated and the schematic diagram of hardware connection is given.The method for developing firmware is  also introduced.Experiment result verifies its feasibility.

Using Extrapolation Technique to Obtain Far-field RCS of Aircrafts

GUO Ri-Feng, LI Nan-Jing, HU Chu-Feng

. 2010, 23(8):  81. 

Abstract ( 1291 )   PDF (837KB) ( 749 )  

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An extrapolation technique by correction dealing with near-distance RCS measurement of aircraft targets is set up.In general,the far-field condition is hard to meet in RCS measurement.According to shape of aircraft targets,an illuminating spherical wave can be equivalent to cylindrical wave.An arithmetic utilizing conductive board as a reference deduces the phase-correction coefficient g(x) between cylindrical and plane wave,then far-field RCS of target can be gained.By simulation for a simple target,the RCS extrapolated can be obtained correctly.Experimental results of complex aircraft target at different distances show that the RCS after extrapolating makes an agreement precisely,moreover,it permits the measurement distance reduced the minimum distance of far-field.Also,there is no serious limitation of measurement for target in dimension of aperture and depth.

A Compact Triple-Band PIFA with a Parasitic Unit

LI Kuan, WU Di, YU Ying

. 2010, 23(8):  85. 

Abstract ( 1651 )   PDF (500KB) ( 926 )  

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This Paper presents a compact tripleband PIFA with parasitic unit working for GSM850/DCS1800/PCS1900.The bandwidth is 820~930 MHz and 1 690~2 120 MHz at S^₁₁<-5 dB.for the GSM850/DCS1800/PCS1900,the measured peak gain is 3.09 dB,4.41 dB and 3.40 dB respectively,which meet the performance requirements of the mobile terminals working in the triple-band of GSM850/DCS1800/PCS1900.The proposed antenna is compact,lightweighted,and applicable in mobile communication terminals.

Design of Wire Feed Circuit with Uniform Speed for a Soldering Machine

YU Bai-Nan

. 2010, 23(8):  87. 

Abstract ( 1070 )   PDF (468KB) ( 859 )  

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This paper introduces design philosophy and practical circuit of wire feeding with uniform speed for a soldering machine.With the technology of Pulse Width Modulation and making automatic feedback regulation,the power supply voltage of DC feeding motor will change with motor torque in order to feed wire stably.Experiments have shown that this circuit has high ability of feedback regulation and the soldering machine can feed wire with uniform speed.

Localization with Radio Irregularity in Wireless Sensor Networks

LIU Chao, WANG Jing-Dong, LI Peng

. 2010, 23(8):  90. 

Abstract ( 1698 )   PDF (584KB) ( 1143 )  

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To get high precision of localization with radio irregularity in WSN（wireless sensor network）,a multi-node localization method based on RSSI is proposed.The position is acquired approximately to predict the angle of each antenna,then the RSSI based on the angle is processed,and the positions of anchor node is used to calculate the position of the node.The experiments show that the average location error is improved from 40% to less than 10%.

Research into Status Data Exchange in Virtual Instruments Simulation of the Sequential Circuit

HUANG Jin-Wen

. 2010, 23(8):  94. 

Abstract ( 1512 )   PDF (701KB) ( 1076 )  

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The status data exchange in the simulation of sequential circuit is studied,the method of constructing virtual trigger unit is analyzed,and the problem of temporarily stored output status data from virtual storage units is resolved.Both theoretical analysis and confirmatory experiments were applied in the study.The work is helpful to the design of digital circuit experiment and improvement of teaching method based on virtual instruments,and also provides more potential applications of virtual instruments.

Design of Laser Marking Controller Based on DSP

TANG Yu-Jun, YUAN Zi-Jun, ZHAO Yong-Li, WU Ben-Ke

. 2010, 23(8):  97. 

Abstract ( 1833 )   PDF (587KB) ( 1104 )  

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The design of laser marking controller based on DSP is introduced in this paper.TMS320F2812 DSP is selected as the processor of this system,and CPLD is used to extend I/Os,USB interface to transfer data,and high speed D/A convert control scanners to rotate.In terms of the D/A converting circuit,aimed to attain bipolar voltage references,operational amplifier MCP606 and MCP1525 is used to produce ±2.5 V high precision voltage reference.Graphics and characters are separated in the marking software to show the change in word size and font precisely.The design of both hardware and software are elaborated in detail.The controller improves the speed and precision of laser marking.

Design of the Multiuser Combination Lock

ZHANG Ying

. 2010, 23(8):  100. 

Abstract ( 1690 )   PDF (491KB) ( 915 )  

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The multiuser combination lock is characteristic of secrecy,flexibility,and safety.The master user does not need to replace the password to prevent the preceding user entry once more,thus enhancing the housing security of another user.Therefore its use may save the trouble of changing the lock to reduce the cost and enhance the security.Based on the multiuser combination lock design,the at89C51 monolithic integrated circuit chip is introduced,and hardware and software design of the multiuser combination lock are given.

UHF Data-link Parameter Determination Method

YANG Jian

. 2010, 23(8):  103. 

Abstract ( 1304 )   PDF (678KB) ( 1131 )  

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With the real-time differential GPS wireless data link developed for air-to-air multi-airplane  flight-test mission as an example,this paper presents the composition of UHF data-link and the determination of such parameters as effective range,antenna performance,propagation loss and tolerance,which can be used as references for relative technicians.

Cross-views Process Detection Based on the Hardware-assisted Virtual Machine

LING Chong, WU Zhi-Yong, SUN Le-Chang, LIU Jing-Ju

. 2010, 23(8):  105. 

Abstract ( 1001 )   PDF (821KB) ( 989 )  

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The current process hiding and detection technologies are analyzed,and the mechanism of cross-views discrepancy utilized by Strider GhostBuster are studied in detail,and based on Hardware-Assisted Machine a new framework for process detection is proposed,namely HCDP,whose effectiveness and integrality are verified through experiment.

Design of Screen Layout Control Based on the Observer Pattern

LIU Hao, DONG Qiu-Hong

. 2010, 23(8):  110. 

Abstract ( 1262 )   PDF (601KB) ( 836 )  

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In software design processing,it often arises that an object's behavior causes the corresponding behavior of several other objects.Observer pattern as a design mode has resolved the reuse problem of the above objects with dependence of one to many.Based on the analysis of the ideas Observer pattern,the paper designs a screen layout control with the C# language and achieves fairly good results.

Embedded Operating System Security Solutions and Configuration

LI Wei, WAN Xiao-Dong

. 2010, 23(8):  112. 

Abstract ( 1187 )   PDF (927KB) ( 930 )  

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In view of the poor reusability and extensibility of safe operating system design,a set of construction scheme is designed based on a study of embedded operating system security and ARINC653 frame standard,which realizes extensible configuration and introduces the predictability safety inspection mechanism.

Application of Database Connection Based on ASP

ZHANG Jun-Lan, DU Xin-Juan

. 2010, 23(8):  115. 

Abstract ( 1301 )   PDF (958KB) ( 910 )  

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This paper first introduces the ASP technology and its application,analyses the working flow and principles of accessing the three database connection methods of ODBC,OLE DB,ADO in ASP,and discusses the realization of database connection upon user login by ASP technology with ADO database connection as an example.Finally,the applications of ASP technology and its future trends are presented.

A New Graphical Password Scheme Against Shoulder Surfing

QU Li-Mei, ZHAO Xiao-Bo

. 2010, 23(8):  118. 

Abstract ( 1543 )   PDF (781KB) ( 883 )  

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A novel g graphical password scheme based on choosing multiple images is proposed in this paper.Different from the existing graphical password schemes,this scheme uses the click on keyboard to choose the pass-icons in stead of the mouse-click manner.The advantage of this scheme is its good resistance to the shoulder surfing attack and intersection attack so that the security of the scheme is enhanced greatly.

Security Measures for the Distribution System

HE Ling-Hui

. 2010, 23(8):  121. 

Abstract ( 1555 )   PDF (502KB) ( 873 )  

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In view of a shock death accident of the low pressure side user caused by the arrester explosion of the high-pressure side of 10 kV distribution transformers,this paper analyzes the cause of the accident of electric shock and proposes some ensure effective measures for the protection of distribution system and personal safety.

Application of Electronic Simulation Technology in Biomedical Engineering Experiments

LIU Jia

. 2010, 23(8):  124. 

Abstract ( 1087 )   PDF (394KB) ( 832 )  

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This paper describes the characteristics of traditional experimental and electronic simulation experiments,and explores the electronic simulation experiments in the teaching of biomedical engineering practice.

Study of the Teaching of Fundamental for Computer Application Course

MING Qiao-Ying

. 2010, 23(8):  125. 

Abstract ( 1193 )   PDF (396KB) ( 772 )  

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For computer-based course teaching,the article proposes a variety of theoretical and experimental teaching methods,as well as other assisted teaching methods,in order to cultivate human resources that meet the demand of nowadays development.