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2018, 38(8): .

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2018, 38(8): .

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Abstract:

Study on the Characteristics of Underwater Explosion Bubble Near Perforated Rigidwall

ZHANG Chang-suo, XUE Jian, WANG Cheng

2018, 38(8): 771-778. doi:10.15918/j.tbit1001-0645.2018.08.001

Abstract(949) PDF(627)

Abstract:
Bubble jet near circular hole was simulated based on Autodyn, bubble motion was divided into two types, the motion of bubbles broken by hole jet and the motion of bubbles broken by wall jet, the influence of hole radius, detonation distance and loading capacity on bubble characteristics was analyzed. The analysis of the parameters-jet velocity, pressure, pulsation period and center displacement of bubbles-show that the decrease of hole radius is of great benefit to the jet formation in the opposite direction of the wall. In addition, the comparison results show that under similar conditions the peak pressure, velocity and pulsation period of the rigid wall with holes are lower than those of the rigid wall without holes.

Sensitivity Analysis Determination and Optimization of Rock RHT Parameters

LI Hong-chao, CHEN Yong, LIU Dian-shu, HUANG Yong-Hui, ZHAO Lei

2018, 38(8): 779-785. doi:10.15918/j.tbit1001-0645.2018.08.002

Abstract(1194) PDF(508)

Abstract:
Among the total 34 parameters of RHT constitutive model, there are 19 parameters can be confirmed from experiment or theoretical study, but the left ones,N、p_comp、f_t^*、f_s^*、A、n、Q₀、g_c^*、ξ、D₁、ε_p^m、A_f、n_f、Bandg_t^*, are generally hard to acquire. A sensitivity study of the 15 hard-acquired parameters was conducted through numerical simulation of uniaxial and triaxial compression of limestone using LS-DYNA. And then a new method was proposed in this paper to acquire all 34 parameters of RHT model in terms of red sandstone by orthogonal experiment coupled with static test, sonic wave test, SHPB impact test and LS-DYNA numerical simulation. The simulated result of red sandstone is in a well line with the result from SHPB impact test of red sandstone, which evidenced the RHT model of red sandstone is effective.

Optimal Configuration Sequence of Steel,Ceramic and UHMWPE Fiber Laminates for the Anti-Fragment Penetration

YE Teng-ke, XU Yu-xin, YANG Sheng, WU Yue, CHEN Ya-sha

2018, 38(8): 786-791. doi:10.15918/j.tbit1001-0645.2018.08.003

Abstract(1039) PDF(454)

Abstract:
The optimal configuration sequence for the anti-fragment penetration performance of steel, ceramic and UHMWPE fiber laminates was studied in this paper. With the same impact velocity, penetration tests of ballistic gun-propelled cylindrical fragments to 5 kinds of composite structures with the same areal density had been carried out to seek the optimal configuration sequence. The comparison of penetration effect between 5 kinds of composite structures showed that steel/UHMWPE composite structure is superior in ballistic resistance. Then, the specific energy absorption was calculated to compare the anti-penetration capability of steel/UHMWPE composite structure with Q235 steel. The results showed that the specific energy absorption of steel/UHMWPE composite structure is 3.55 times as high as that of Q235 steel.

Experimental Research of Characteristics of Initiation Response of PBXC03 Under Quasi-Isentropic Loading

LIU Hai-qing, DUAN Zhuo-ping, CAI Jin-tao, OU Zhuo-cheng, WANG Gui-ji, HUANG Feng-lei

2018, 38(8): 792-796. doi:10.15918/j.tbit1001-0645.2018.08.004

Abstract(800) PDF(384)

Abstract:
In order to explore the characteristics of explosive's initiation and the detonation growth in the explosive under quasi-isentropic loadings, a one-dimensional initiation response test system under quasi-isentropic loadings was established by the magnetic compression device CQ-4 and the multichannel photonic Doppler velocimetry (PDV). Surfaces of five PBXC03 samples with different thicknesses were compressed by the quasi-isentropic loading so as to obtain particle velocities of sample's reverse sides. Results show that the waveforms of particle velocities obtained are clean and details of them are clear. After the quasi-isentropic loading enters into the explosive, a precursor shock wave is formed by the chasing and convergence of quasi-isentropic waves. And, initiation mechanisms of the explosive under quasi-isentropic loadings have obvious differences from that under impact shock loadings. Before the formation of the strong precursor shock wave, few hot-spots are formed and no reaction occurs in the explosive. Otherwise, the response of the explosive performs as characters of initiation and detonation dominated by the hot-spot initiation mechanism after the strong shock wave is formed.

Mechanism of the Increase of Solidification and Cooling Rate of Melt-Casting Explosive by Increasing the Pressure of the Casting Vessel

ZHU Dao-li, ZHOU Lin, ZHANG Xiang-rong, WANG Duan-ying, WANG Ji-ming

2018, 38(8): 797-801. doi:10.15918/j.tbit1001-0645.2018.08.005

Abstract(840) PDF(317)

Abstract:
In order to reveal the mechanism of the increase of solidification and cooling rate of melt-casting explosive by increasing the pressure of the casting vessel, the interfacial heat transfer coefficient (IHTC) between the explosive charge and the mold was determined by the one-dimensional thermal conductivity experiment and the numerical inversion method, which was a function of both the time for solidification and cooling and the pressure of the casting vessel. The results show that the IHTC is increasing with the increase of the applied pressure, which is responsible for increasing the solidification and cooling rate of the explosive charges.

B-Spline Surface Transition/Fine-Tuning Reduction Method in Reverse Reconstruction

JIANG Shu-feng, ZHANG Ying-qi

2018, 38(8): 802-807. doi:10.15918/j.tbit1001-0645.2018.08.006

Abstract(827) PDF(312)

Abstract:
In order to improve the accuracy and efficiency of the reduction and reconstruction of point cloud data in reverse engineering, the application of B spline surface fitting in curvature reduction and surface reconstruction was improved. The 3D scanning technology, 3D design, point cloud data simplification and model reconstruction in reverse engineering were applied and studied in depth and detail. A reduction algorithm based on B-spline surface transition/fine tuning was proposed. The research was applied to reverse manufacturing of impeller. Point cloud data can be reconstructed by 3D scanning, and the point cloud data can be encapsulated and simplified reasonably. Surface reconstruction and 3D redesign were carried out, and the smoothness and precision of the product were analyzed at the same time. Finally, the product model sample was printed out by the rapid prototyping machine. The research results show that the proposed method not only improves the efficiency of surface modeling, but also improves the accuracy of inverse modeling.

A Burst Height Calculation Method Based on Millimeter Detector for Optional Burst Height Fuze

CHENG Cheng, GAO Min, ZHOU Xiao-dong, LIU Zhen-ya

2018, 38(8): 808-813. doi:10.15918/j.tbit1001-0645.2018.08.007

Abstract(848) PDF(602)

Abstract:
In order to meet the burst height requirements of a new generation long-range guided rocket projectile, a novel large dynamic optional burst height fuze based on phased array detector was proposed and analyzed in this paper. Due to the burst height of the proposed single-type fuze was assigned to be larger range, optional burst height, satisfying the burst height of larger power warhead and electromagnetism pulse warhead, adapting the discharge height of composite warhead, improving the precise strike ability for army corps and so on, a burst height calculation method was proposed based on millimeter phased array detector for the optional burst height fuze. Firstly, integrating the height measure data of the phased array detector and the inertial navigation data, the height of the rocket was calculated in real time to realize the burst height control. Then the fusion results were regarded as initial value of inertial navigation height measurement to calculate the height at next moment, reducing the measurement error caused by time accumulation and improving the height measurement accuracy. Simulation results show the validity of the method and the calculation precision of the burst height.

Application of the GPS Receiver in Circumlunar High-Speed Re-Entry Spacecraft

WANG Meng, ZHOU Bo, LIU Ying-na

2018, 38(8): 814-819. doi:10.15918/j.tbit1001-0645.2018.08.008

Abstract(871) PDF(498)

Abstract:
Inertial navigation unit (IMU) was used as the main navigation sensor in the 3rd Stage of China Lunar Exploration Program in China. A light-weight, miniaturization and fast positioning GPS receiver suitable for high speed re-entry capsule was developed. It effectively solved the poor accuracy problem of IMU long-term error accumulation, with fusion of GPS data and IMU data. Flight results indicate that navigation result was first given by GPS receiver at 4 911.3 km orbital altitude. The effective positioning time lasts 16 min. There are two times through the black barrier area in the atmosphere. Evaluated results indicate that root mean square error of position is less than 3.67 m, and root mean square error of velocity is less than 0.19 m/s. The GPS receiver meets the high-speed re-entry flight requirements. It is feasible for application of medium or low orbit micro satellites and deep space re-entry spacecraft.

Online Identification Method for Tactical Maneuver of Target Based on Air Combat Maneuver Element

JIA Zhen-ze, FAN Xiao-guang, XUE Ming-hao, ZHANG Song

2018, 38(8): 820-827. doi:10.15918/j.tbit1001-0645.2018.08.009

Abstract(863) PDF(388)

Abstract:
The online identification for tactical maneuver of target can provide important information for air combat situation sensing, mission planning and aid decision making. Since the radar data cannot provide the posture information, it is difficult to describe the tactical maneuver of the enemy vehicle. In this paper, a two-stage recognition system for tactical maneuver of target based on air combat maneuver element (ACME) was proposed. First, the information from airborne radar was analyzed. Then, tactical maneuver was decomposed into eleven ACMEs according to the trajectory analyzing, thus simplifying the maneuver representation. And then, a recognition method utilizing random forest and support vector machine was designed, in the first stage, recognizing ACMEs with trajectory parameters, in the second stage, identifying tactical maneuver based on ACMEs sequence and motion parameters. Finally, the simulation results show that typical maneuver can be represented effectively by ACMEs and identified correctly by the recognition method.

Autonomous Collision Avoidance Technique of Cruise Missiles Based on Modified Artificial Potential Method

FAN Shi-peng, QI Qi, LU Kun-feng, WU Guang, LI Ling

2018, 38(8): 828-834. doi:10.15918/j.tbit1001-0645.2018.08.010

Abstract(1250) PDF(467)

Abstract:
A novel methodology has been developed for path planning of cruise missile.To solve the local minimum problem of traditional artificial potential field method,minima were divided into two types.The judgment theorems and criterions were given respectively,and the corresponding solutions were proposed to eliminate the local minima.Then,available overload condition was taken into consideration,and potential fields were generated by using logarithmic function to represent the goal and no-fly zones.Furthermore,operational region of repulsive forces and attractive force was set reasonably,and the parameters of potential were adjusted for purpose of avoiding collision.Under the influence of the potential fields,a flyable path is found to reach the goal.Finally,the mathematical simulation results demonstrate the effectiveness of the proposed approach.

Design and Simulation of Greenhouse Temperature Hierarchical Control System

CHEN Li-jun, DU Shang-feng, HE Yao-feng, LIANG Mei-hui

2018, 38(8): 835-840. doi:10.15918/j.tbit1001-0645.2018.08.011

Abstract(700) PDF(445)

Abstract:
For greenhouse crop system, significant differences in response times exist. Crop dry matter production responds rather slowly to the changes in the environmental conditions while the greenhouse temperature responds relatively fast. For this reason, a greenhouse temperature hierarchical control system was proposed. The hierarchical system was designed with two layers, including the crop layer and the climate layer. First, in the crop layer, a decoupled lower order model was established based on the theory of singularly perturbed systems. The controller was handled by means of an optimal control approach to achieve temperature set points, minimize the net cost according to objective function. Then, a fuzzy controller in the climate layer was designed to cope with the problem of tracking set points obtained from the crop layer. At last, the designed hierarchical control system was tested in Matlab. The simulation results show that both the crop and climate layer controllers can work well with better control performance.

An Adaptive Defragmentation Restore Optimization Method Based on Cloud Storage System

HE Qin-lu, BIAN Gen-qing, SHAO Bi-lin, YE Na

2018, 38(8): 841-847. doi:10.15918/j.tbit1001-0645.2018.08.012

Abstract(826) PDF(390)

Abstract:
To solve the problem of the recovery performance drop caused by data fragmentation in the deduplication-based cloud storage system,an adaptive fragmentation grouping was used to design a method for data recovery after deduplication in a cloud storage system.The approach was arranged not to use a fixed-size read window,to identify and delete the fragmentation,and to select a different reference chunk to minimize the number of containers.The number of referenced blocks could reduce disk access to accurately identify and remove fragmented data,improving data recovery performance and deduplication rates.The results show that,the approach can improve restore performance while reducing the amount of rewrite data.

3D Hand Vein Recognition Based on Normal Distribution Transform for Multi-Pose Authentication

ZHOU Ya, QI Yong, HU Xiao-ming, HU Xin-ran, WANG Nan

2018, 38(8): 848-853,860. doi:10.15918/j.tbit1001-0645.2018.08.013

Abstract(652) PDF(402)

Abstract:
A multi-pose hand vein recognition algorithm was proposed based on 3D point cloud matching. Considering the characteristics of hand vein point cloud,an extended database that combines 3D feature arrays and vein point cloud data was established according to stereo vision principle. A 3D feature array based calculation method was proposed for coarse point cloud registration. In stereo vein image, the stable feature points were extracted and reconstructed to three-dimensional features. The posture difference of hand vein point clouds was eliminated according to the result of 3D feature matching. An improved normal distribution transform algorithm was used to complete the vein point cloud matching. Experiment results show that the proposed algorithm can effectively improve the recognition rate under multi-pose. The recognition rate of the system can be more than 90%, even if the hand posture changes in a large range.

Design and Simulation on a New Dual-Polarized Antenna Fed by SICL

GAO Zhi-wei, ZHANG Shuai, CUI Li

2018, 38(8): 854-860. doi:10.15918/j.tbit1001-0645.2018.08.014

Abstract(773) PDF(391)

Abstract:
A novel scheme of dual-polarized antenna fed by the substrate integrated coaxial line (SICL) was proposed. The design can enlarge the impedance band of the dual-polarized antenna and realize the direct assembling of two orthogonal printed circuits. A SICL feeding structure based on multiple layer substrates was designed. For this SICL feeder, a wide band Balun from SICL to non-coplanar was introduced, which realized the transforming of un-balanced SICL port to balanced non-coplanar strip line. A wide band tapered impedance matching circuit from SICL to microstrip line was designed. Within the frequency range of 2.2 GHz to 2.8 GHz, the simulated isolation degree between two polarization ports is higher than 20 dB, the wide angle coverage pattern at each port is achieved, the cross polarization level at the boresight is lower than -20 dB, and the high radiation efficiency is realized. The measured result of the fabricated antenna is close to the simulation result, which verifies the feasibility of the scheme.

A Novel Tracking Differentiator with Good Stability and Rapidity and its Application

YAO Zhi-ying, CAO Hai-qing

2018, 38(8): 861-867. doi:10.15918/j.tbit1001-0645.2018.08.015

Abstract(860) PDF(412)

Abstract:
A novel tracking differentiator with high stability and rapidity was studied to quickly track the object signal and correctly resolve its differentiation,which was applied to control the attitude of the non-stationary antenna.A novel non-smooth controller of the second system with a bounded disturbance was proposed;its stability,rapid convergence and strong disturbance rejection ability were studied.A novel tracking differentiator with high stability and rapidity (HSSTD) was proposed with the help of the non-smooth controller and a nonlinear tracking differentiator,its stability is proved in theory.Experiments validate the tracking differentiator can quickly track the object signal and correctly resolve its differentiation.The novel tracking differentiator is been applied in the attitude PID control of non-stationary antenna.Experiments prove the novel tracking differentiator can help the non-stationary antenna to track the target satellite quickly and stablely and ensure communication with a high quality.

Multi-Channel Electrode Tissue Impedance to Suppress Motion Artifact in Ambulatory Electrocardiogram

ZHANG Huan-qian, ZHANG Shu-lin, DU Xiao-wei, JIN Qing-hui, LIU Xue-hua, LI Qing, YANG Jian, ZHAO Jian-long

2018, 38(8): 868-873. doi:10.15918/j.tbit1001-0645.2018.08.016

Abstract(1034) PDF(371)

Abstract:
A novel multi-channel electrode tissue impedance (MC-ETI) detection method was proposed to monitor the ambulatory electrocardiogram (AECG) and ETI signals. Without changing its input stage, this method can make the amplifier's input impedance remain enough high level by a low cost discrete circuit. To assess the performance of this method, twenty experiments in ten healthy volunteers were carried out. Simulation results show that the reference signal generated by MC-ETI has the strong correlation with MA in AECG (median=0.599). Comparing with single-channel electrode tissue impedance (SC-ETI) method, MC-ETI can achieve the same performance with a simple system.

Performance of Mn-Doped Sr₂Fe_1.5Mo_0.5O_6-δas the Anode of Intermediate Temperature Solid Oxide Fuel Cell

GOU Man-li, ZHANG Ji-fang, WANG Zhen-hua, SUN Wang, QIAO Jin-shuo, SUN Ke-ning

2018, 38(8): 874-880. doi:10.15918/j.tbit1001-0645.2018.08.017

Abstract(859) PDF(426)

Abstract:
In this paper, a material Sr₂Fe_1.4Mn_0.1Mo_0.5O_6-δ(SFMn0.1M) was synthesized by a sol-gel combustion method and taken as anode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). The crystal structure, microstructure, element valence, conductivity and electrochemical properties of SFMn0.1M were characterized. The results of X-ray diffraction (XRD)show that, Mn-doped SFMn0.1M still possesses pure perovskite crystal structure and the 3D interconnected network microstructure composed of nano-particles. The results of electron microscope (SEM) scanning reveal the interconnected porous structure of SFMn0.1M. In addition, SFMn0.1M exhibits excellent electrochemical performance with the highest conductivity of 14.7 S·cm^-1at 800℃; and the peak power densities of single cells based on the SFMn0.1M anode can reach 565.2, 385.2, 303.9 and 141.2 mW·cm^-2at 800, 750, 700 and 650℃, respectively. All these results show that SFMn0.1M material is a promising anode for IT-SOFCs.

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