Table of Content

31 December 2008, Volume 29 Issue 12

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Paper

Theoretical Model for the Calculation of Concrete Target Resistance and Numerical Simulation of Penetration by Shaped Charge Jets

WANG Jing, WANG Cheng, NING Jian-guo

2008, 29(12):  1409-1416.  doi:10.3969/j.issn.1000-1093.2008.12.001

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A model to predict the resistance of concrete target based on the material properties was de?veloped by using the spherical cavity expansion theory. The predicted values were compared with some experimental results to verify the reliability of the target resistance model. The formation of jet at dif?ferent liner cone angles and the penetration of shaped charge jet into concrete target were numerically- simulated with AUTODYN-2D code. The reliability of numerical simulation results of the formation of shaped charge jets was verified by comparing them with flash X-ray high-speed photograph results. The jet velocity distributions wer.e obtained by numerical simulation results, and virtual points were then calculated. Simulation results are in agreement with the theoretical predictions. Results show that the cavity expansion model to predict the resistance of concrete target is feasible and reliable.

The Self-sensitizing Structure of Expanded Ammonium Nitrate with Different States

ZENG Gui-yu, Lü Chun-xu, HUANG Hui

2008, 29(12):  1417-1421.  doi:10.3969/j.issn.1000-1093.2008.12.002

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The expanded ammonium nitrate(EAN) samples with different states were prepared by us?ing a vacuum crystallizing technology. The structure characters, such as porosity, pore structure, spe?cific surface area, particle surface shape and surface defects, and detonator initiation S— work capacity of common ammonium nitrate(AN) and EAN with different states were investigated us?ing density measuring, N2 adsorbing, scanning electric microscopy (SEM) and plate trace test meth-ods The results show that the particle surface of common AN is smoother, denser, lower p_ty an specific surface area than that of EAN; the particle surface of EAN is rather irregular, has edges, pro?tuberances, severe dismatation crystal form, larger specific surface area and porosxty than those o un?expanded AN, typical self-sensitized structure characters; the detonator initiation sensitivity an wor capacity of ammonium nitrate-fuel oil (ANFO) made of different states of AN are closely related to the self-sensitized structures of EAN; the expanded ANFO sample has higher detonator initiation sensitivi?ty and work capacity compared to un-expanded ANFO sample. The characterization techmques can be used to reveal the self-sensitizing structure of EAN with different states.

A New Multi- threshold Frequency Domain Constant False Alarm Rate Detection Algorithm for Radar Fuse

HAN Meng-fei, CUI Wei, WU Si-liang

2008, 29(12):  1422-1426.  doi:10.3969/j.issn.1000-1093.2008.12.003

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A new multi-threshold frequency domain constant false alarm rate detection algorithm for radar fuse was presented. In accordance with the movement characteristics of the radar fuse targets, this algorithm includes time domain and frequency domain thresholds based on traditional time domain dual-threshold detection algorithm, that is, the algorithm uses the multi-threshold detection techniques to reduce the false alarm probability. The simulation and experimental results show that this detection algorithm can be used to achieve both low probability of false alarm and reliable target detection even under low signal-to-noise ratio condition. It is real-time and easy to be implemented.

Research on Signal Processing for Through-the Wall Surveillance Based on Stochastic Resonance

GUO Shan-hong, SUN Jin-tao, XIE Ren-hong

2008, 29(12):  1427-1431.  doi:10.3969/j.issn.1000-1093.2008.12.004

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The echo expression of through-the wall surveillance (TWS) detector based on continuous wave is derived, and a simple harmonic vibration model based on the movement characteristics of hu-man body is adopted. The comparison of experimental signal to simulated signal indicates that the echo of TWS detector is fitted well with the moael. According to the characteristic of echo, stochastic reso?nance method is applied to detect the target. Concretely, nonlinear bistable system and twice sampling stochastic resonance method are used. The desired signal of TWS echo is enhanced while the noise voltage is reduced when it is passed through the nonlinear bistable system. The signal detection proba?bility and false alarm probability are also simulated by using the method of cell averaging constant false alarm ratio. The simulation indicates that when the echo is passed through a nonlinear bistable system, the signal detection probability is raised and the false alarm probability is decreased while the noise power among a definite range.

Integrated Acousto-Optic Frequency Shifter

LIU Zhi-hua, SHI Bang-ren, KONG Mei

2008, 29(12):  1432-1436.  doi:10.3969/j.issn.1000-1093.2008.12.005

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Acousto-optic(AO) frequency shifter that consists of a pair of geodesic waveguide lenses for collimating and focusing and a pair of cascade waveguide AO Bragg cells was realized in a Ti diffused y cut LiNb〇3 waveguide substrate with 46 mm X 2.5 mm X 30 mm in size. Optimized ideal waveguide geodesic lens profile and AO parameters were numerically calculated and designed. Transmission loss of 1.2 dB and diffracted facula’ s full width at half maximum (FWHM) of 4.5 μm were measured for geodesic lens. All the chips have 3 dB modulation banawidth of 10 MHz and coupling insertion loss of 20 dB with single-mode optical fiber at driving baseband frequency of HO MHz.

Experiment and Numerical Simulation of Shock Wave Propagation and Bubble Impulse of Underwater Explosion

Lljian，RONG Ji-li, YANG Rong-jie,ZHANG Tao

2008, 29(12):  1437-1443.  doi:10.3969/j.issn.1000-1093.2008.12.006

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Experimental investigations were carried out on the shock wave propagation and bubble im-pulse of underwater explosion of the spherical TNT and cylindrical aluminized explosives. The physical process of underwater explosion under gravity was simulated and analyzed using MSC. DYTRAN finite element analysis software. The computational results were compared with experimental results, which show that the structure-fluid coupling method can be used precisely to simulate the propagation of shock wave and the motion of bubble. The effect of grid density, length-diameter ratio of cylindrical explosive, propagation distance and explosion angle on the peak pressure of shock wave was analyzed and summarized. The finite element model, method and computational results in the study are of a certain reference value to relative engineering research and calculation.

Numerical Analysis of Structure and Dynamic Characteristics of Suppercavitating Flow Aroxmd a Disc Cavitator

YU Zhi-yi, WANG Guoyu, GU Ling-yan,ZHANG Min-di

2008, 29(12):  1444-1449.  doi:10.3969/j.issn.1000-1093.2008.12.007

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The unsteady supercavitating flow around a disc cavitator was numerically studied using the ANSYS- CFXlO .0 software under the assumption of homogeneous media. The turbulence effects were modeled by the customized filter-based turbulence model, and the cavitation was evaluated by the Rayleigh-Plesset equation based mass transfer model. The shape of supercavity was calculated, and the dynamic characteristics were analyzed. The results reveal that the supercavitating flow region around the disc cavitator is composed of an upstream high vapor volume fraction (VVF) region and a down?stream vapor-liquid mixture region, the former has a stable cavity shape due to its stable stagnation vortex pair, the latter expands downstream with the development of the rear vortex and becomes ulti?mately a quasi-conical cavitation zone; the lift force and the drag force acting on the disc cavitator be?come stable swiftly in the formation process of supercavitation.

Microstructure and Optical Properties of Low Temperature MBE-grown Amorphous InGaAs Film

YAO Yan-ping, LIU Chun-ling, QIAO Zhong-liang，LI Mei, GAO Xin, BO Bao-xue

2008, 29(12):  1450-1453.  doi:10.3969/j.issn.1000-1093.2008.12.008

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The amorphous InGaAs films were prepared by molecular beam epitaxy (MBE) with differ?ent V / Ⅲ flux ratios of 40 :1 and 60 :1. Mole fraction, X-ray diffractometer (XRD) characteristics, morphology and optical properties of the sample were measured by energy dispersive X-ray spectropho?tometer (EDS), XRD, scanning electron microscopy (SEM) and spectrophotometer. The analysis methods of radial distribution function and pair correlation function were established from XRD in or?der to analyze the sample microstructure. Moreover, the average distance between the nearest neigh?bouring atoms, atom coordination numbers of the nearest neighbouring atoms and the short range reg?ular domains were calculated and analyzed. At the same time, the near-infrared absorption coefficient was calculated from the transmission spectra. The optical band gaps of samples are 0.886 eV and 0.822 eV, respectively.

Design and Experiment for Topological Interlocking Fragile Composites Structure

WEI Feng-chun, YANG Zhi-hong, ZHANG Na, ZHANG Heng

2008, 29(12):  1454-1457.  doi:10.3969/j.issn.1000-1093.2008.12.009

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A new kind of fragile composite material structure was designed based on topological inter-locked principle. In this structure every part without bonding can lead the interlocking function to be vanished under the condition of unconstraint. The topological interlocking fragile composites structure composed of isosceles right-angled triangle plate was prepared by high precision compression molding. The mechanical behaviors of this structure under the different lateral loads and its load capacity were studied with the help of experiment and the FEM methods. The results show that the displacement changes with the force nonlinearly when a vertical point load is applied on this structure. The FEM calculated results agree well with the experimental results.

A Research on Preparation of Nanometer a-Al2O3 Powders

ZHAI Qing-zhou, LAI Xi

2008, 29(12):  1458-1461.  doi:10.3969/j.issn.1000-1093.2008.12.010

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Nanometer a -Al2O3 was prepared by using NH4Al(SO4)2. 12H2O as raw material and solu?ble starch as dispersant by means of solid phase method. The sample obtained was characterized by powder X-ray diffraction (XRD)，Fourier transform infrared spectroscopy (FTIR) and transmittance electronic microscopy (TEM). Powder XRD results indicate that the product is a-Al2O3 and the crys-tallite diameters of the powders are 50 nm. FTIR spectra show that the sample has a strong absorption band at 574 cm-1, which is the characteristic absorption band of nanometer AI2O3 and corresponds to a vibration absorption of Al—〇 key. From thermogravimetry-differential thermal analysis (TG-DTA) curves, the thermal decomposition process of the reactants was judged.

Optimization Matching of Television Reconnaissance Munitions and Naval Gun System

LI Hui, QIU Zhi-ming, WANG Hang-yu, SUN Shi-yan

2008, 29(12):  1462-1466.  doi:10.3969/j.issn.1000-1093.2008.12.011

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Television reconnaissance munitions is a new reconnaissance and detection way for naval gun systems. During the demonstration of the long-distance precise striking capability of naval gun sys?tems, it is an important problem to be solved whether the television reconnaissance munitions could meet the need of naval gun systems for snip to shore long-distance striking. As the target function of the optimization model, the system entire efficacy was calculated by power index and fuzzy weight methods. On the basis of analyzing the matching constraints of key indexes, the optimization model was constructed and transformed into a fuzzy geometric programming, to make the complex matching problem simplification. A typical applied example of matching television reconnaissance munition matching to a certain naval gun weapon system was presented, and its calculation was given. The pro?posed method provides a new idea for index optimization matching of a complex system.

The Coarse Alignment of Strap-down Inertial Navigation System for Ship

XU Bo, SUN Feng, GAO Wei

2008, 29(12):  1467-1473.  doi:10.3969/j.issn.1000-1093.2008.12.012

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A coarse alignment of strap-down inertial navigation system (SINS) for ship was re?searched .Three coarse alignment methods of the traditionally analytical, the second order leveling az?imuth estimation and the novel freezing analytical were deduced, of which the last method is that the calculation of attitude matrix is based on the gravity acceleration information in the inertial coordinate. The stationary and swing bases were simulated and analyzed. The last two methods were used for a re?al SINS based on the fiber gyroscopes and accelerators for a real ship testing at mooring. The test re-sults show that the coarse alignment can be done effectively using the freezing analytical method, and the fine alignment can be allowed based on it.

Plume Source Localization Based on Bayes Using Wireless Sensor Network

KUANG Xing-hong, SHAO Hui-he

2008, 29(12):  1474-1478.  doi:10.3969/j.issn.1000-1093.2008.12.013

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A wireless sensor network (WSN) was introduced into predicted evaluation of plume source localization. Based on the Bayes principle, an improved particle filter (IPF) algorithm was proposed, which is adapted for the gas pollution source localization using WSN. It was used to improve the filter performance that the methods of the weighted centraid, the backoff timer sorting and the residual re?sampling were adopted to determine the initial point of predicted location, the information sorting of located node and reduce the sampling variance respectively. The comparison of the simulated location performances among the IPF, the extended Kalman filter (EKF) and the improved non-linear least square (I-NLS) shows that WSN is effective on the plume source localization; IPF is better than EKF and I-NLS.

Angular Glint of Aircraft Formation and Its Applications

WANG Chang-qing, WANG Xin-min, SHI Xiaoli

2008, 29(12):  1479-1484.  doi:10.3969/j.issn.1000-1093.2008.12.014

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The angular glint of aircraft formation was studied for avoiding it to be intercepted. The an?gular glint of the aircraft formation was modeled as an evenly distributed i\-point scattering center, and the linear error of the angular glint and its distribution characteristics were calculated with the phase gradient method. A mathematical model of the apposition between four aircrafts in different for?mation modes and a typical surface-to-air missile was established. A simulation was performed by the model. The simulated result shows that it is effective to avoid intercepting with reasonable aircraft for?mation mode.

A Magnetic Uisturbance Compensation Method Based on Magnetic Dipole Magnetic Field Distributing Theory

YANG Yun-tao, SHI Zhi-yong, GUAN Zhen-zhen, LI Yu-ze

2008, 29(12):  1485-1491.  doi:10.3969/j.issn.1000-1093.2008.12.015

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The interference of carrier magnetic field to geomagnetic field has been a difficult problem for a long time, which has influence on navigation compass deviation and geomagnetic measurement. How to eliminate the effect of inherent and induced magnetic fields of carrier on the measuring accura?cy of geomagnetics was researched to increase the accuracy of geomagnetic measurement suitable for the need of geomagnetic matching localization. The magnetic dipole magnetic field distributing theory was applied to deduce the magnetic compasition in a position where the sensor is installed on the carrier. A geomagnetic measurement model was established with the ideal sensor magnetic measurement data. And a geomagnetic measurement compensation model including the magnetic disturbance of carrier and the error of sensor was built based on the analysis of the magnetic sensor error, in which the parameter meaning is specific and the errors of carrier magnetic field and magnetic sensor can be compensated in any case. The experimental results show that the model has higher geomagnetic measurement accuracy than that of others.

Microscopic Study of Lrround Surfaces of Drilled Holes in Fibre Reinforced Plastics

ZHENG Lei, YUAN Jun-tang, WANG Zhen-hua

2008, 29(12):  1492-1496.  doi:10.3969/j.issn.1000-1093.2008.12.016

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A scanning electron microscope (SEM) was used to observe the ground surfaces of drilled holes in fibre reinforced plastics (FRP) by using a sintered diamond drill, and accordingly the fracture mechanisms of glass fibre and Kevlar fibre, and the microscopic characteristics of ground surfaces were studied. The SEM observations show that there are six kinds of broken appearances for glass fibre and seven kinds for Kevlar fibre; the ground surface of FRP can be divided into two kinds of area, namely the area covered with polymer resin matrix and the area dominated by broken fibres, with three kinds of fibre fracture area found. To a certain extent, the results acmeved in tms paper reveal the drilling mechanism of FRP.

Formation of p-Type Silicon-based Deep Macropore Channel Array by Utilizing Electrochemical Etching Technology

Gao Yan-jun, Duan-mu Qing-duo, WANG Guo-zheng, LI Ye, TIAN Jing-quan

2008, 29(12):  1497-1500.  doi:10.3969/j.issn.1000-1093.2008.12.017

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The formation of deep macropore channel array of p-type silicon in HF electrolyte was inves-tigated. Then a series of electrochemical etcnmg experiments and tests were carried out in three poles electrobath using different concentration HF electrolytes. The formation mechanism of deep macropore channel array of p-type silicon was theoretically described, and the relationship between the electro?chemical etching reaction and the HF concentration was given. It is shown that that HF concentration is a very important factor that determines whether electrochemical reaction is accomplished or not. The electrochemical etching method of p-type silicon macropore array in aqueous fluoride solutions is eco?nomic and practical for fabricating deep macropores. The experimental consequences are benefit to the electrochemical etching technology of silicon-based deep macropore array.

Research on the Armaments Repair Support Network Design Problem

WANG Wen-feng, LIU Ya-jie, GUO Bo

2008, 29(12):  1501-1508.  doi:10.3969/j.issn.1000-1093.2008.12.018

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For the design problem of armaments repair support network composed of 2 levels of repair facilities of repair depots and a repair base, an integrated optimization decision model was proposed to find the locations of the repair depots, the best service relations between the combat units and the de?pots, and to decide the allocation of the repair facilities. The model object is to minimize the total ex?pected cost on condition that the unwaiting repair probabilities of damaged armaments at the repair fa?cilities are higher than the specified levels. Then a heuristic method based on tabu search algorithm was proposed. And an extension of the model, the service relations between combat units and the repair fa?cilities being given in advance, was discussed. The experimental results indicate that the models and algorithms are useful.

Battle Damage Assessment Based on Bayesian Network

MA Zhi-jun, JIA Xi-sheng, CHEN Li

2008, 29(12):  1509-1513.  doi:10.3969/j.issn.1000-1093.2008.12.019

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With the quickening rhythm of the war and the complication of battlefield environment, the battle damage assessment (BDA) has had a more important effect on the commanderJ s decision. Be-cause of the complexity of modern battlefield and the uncertainty of battle damage information, it is more and more difficult to determine the damage level of target. Bayesian network is a reasoning and predicting tool coming into vogue only in recent decades. It can correctly reason a problem of interest based on the uncertainty and incomplete information, wmch is suited to evaluate the battle damage based on the uncertainty and incomplete target damage information. According to the study of BDA based on Bayesian network, the building and updating process of Bayesian network model were dis?cussed .The feasibility and validity of Bayesian network for BDA were analyzed by taking airport run?way for example.

Research Notes

Analysis of Vibration Modal of a Multibarrel Cannon

ZHANG Hai-hang, DI Chang-an

2008, 29(12):  1514-1517.  doi:10.3969/j.issn.1000-1093.2008.12.020

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For researching vibration characteristics of a certain type multibarrel cannon, a modal analy?sis method was proposed and the experimental points were determined on the basis of its geometric model. The mode analysis system of the cannon was set up on basis of SC310W multi-path data-col?lecting system. Modal experiment of the system was carried out by a nammer hitting method, the re?sponse signals and spectra of impacting prompt power and vibration acceleration and their frequency re?sponse functions were obtained. The first seven-order modes and the corresponding vibration frequen?cies were obtained, confidence factors of modal analysis and complexity of the modal were given, by the steady map method.

Research on Dim Point Moving Target Detection in Infrared Image

YU Jing-song, WAN Jiu-qing, GAO Xiu-Iin

2008, 29(12):  1518-1521.  doi:10.3969/j.issn.1000-1093.2008.12.021

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For detection of the dim point moving target in the infrared image which is fcharacterized by low SNR (signal noise ratio) and the serious background and noise disturbance, an effective detection algorithm was proposed, which consists of the background prediction and target track searching steps. The algorithm was applied to the high-pass nltering of sequence images, made the background predic?tion for the filtered images, and subtracted the original image and the background prediction image to obtain the residual images. A few of candidate targets were separated from the residual images accord?ing to some threshold. The sequence residual images containing candidate targets are synthesized to form a combination frame image by the maximum combination algorithm. The target track was detect?ed from the combination frame image by utilizing the continuity and consistency of target movement.

Implementation of Smith-Fuzzy-Expert-PID Algorithm for Low Temperature Environment Simulation Test System

XING Yong-zhong, XU Zhi-Liang, ZHANG Shao-jie,CONG Pei-xin, CHENG Qi, WU Xiao-bei

2008, 29(12):  1522-1526.  doi:10.3969/j.issn.1000-1093.2008.12.022

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An advanced control method is necessary for large low temperature (air cooling) environ?ment simulation test system because of its complexity, more interference factors and poor safety. For this purpose, a Smith-Fuzzy-Expert-PID control algorithm based on measured data of system dynamic performance parameters was introduced into the system as a control tactics to enhance the adaptability of system control law, the safety of control process, the robustness and automatic control level of the system. The experimental results show that the algorithm meets the requirements of the system and is easily implemented.

Research on a Novel Towed Body Launch and Recovery Electro- hydraulic Proportional System and Synchro- control Strategy

WANG Hai-bo, WANG Qing-feng

2008, 29(12):  1527-1531.  doi:10.3969/j.issn.1000-1093.2008.12.023

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A towed body launch and recovery electro-hydraulic proportional system with volumetric speed control open circuit was designed to make a underwater towed system release and retract the towed body rapidly and safely. The electro- nydraulic proportional system meets the needs of indepen?dent or synchronous operating of towed body. When the towed body is released or retracted syn?chronously, a cable winch and a crane of underwater towed system operate simultaneously. A mathe- matic model was built for the electro- hydraulic proportional system. A synchro- control strategy based on structure invariance principle was proposed to compensate the tension fluctuation of cable due to ve?locity variation of cable winch driven by hydraulic motor and assure the trouble-free execution of syn?chro process. The experimental results show that the electro- hydraulic proportional system and the synchro-control strategy both have good control performance.

Optimization Research on Hydrodynamic Coefficients of Submarine Based on Immune Genetic Algorithm

HU Kun, WANG Shu-zong, XU Yi-fan

2008, 29(12):  1532-1536.  doi:10.3969/j.issn.1000-1093.2008.12.024

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For the optimization of hydrodynamic coefficients in submarine space motion equations, an adaptive weight immune genetic algorithm was used to optimize the hydrodynamic coefficients. Some hydrodynamic coefficients sensitive to the control and maneuvering of submarine were chosen as the optimization variable in the algorithm, by using adaptive weight method to determine the weight and target function, the multi-objective optimization is translated into single-objective optimization. For a kind of submarine, three typical maneuvers of oversnoot maneuver in the horizontal plane, overshoot maneuver in the vertical plane and turning circle maneuver in the horizontal plane were chosen as re-searched oojects. The efficiency of the method was proved by the computer simulation of primal hydro- dynamic coefficient and optimized hydrodynamic coefficient.