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China Ocean Engineering 2019年第3期33卷 253-267页

作者： ZHAO Xi-zeng CHENG Du ZHANG Yi-fei LI Meng-yu Ocean College Zhejiang University Zhoushan 316021 China troops Zhoushan 316021 China troops Ningbo 315171 China

In this study, solitary waves passing over a submerged breakwater are investigated both experimentally and numerically. A total of 9 experimental conditions are carried out, including different incident wave heights and water depths. Numerical simulations are performed using a high-order finite-difference model solving Navier–Stokes (N–S) equations. The predicted water wave elevation, velocity and pressure show good agreement with experimental data, verifying the accuracy and capacity of the numerical model. Furthermore, parametric studies are conducted by numerical modelling to examine the effects of the geometrical features of submerged dike on hydrodynamic characteristics around the breakwater.

关键词： submerged breakwater solitary wave CIP method Navier-Stokes model VOF method

Effect of particle size on the preparation and microwave absorption properties of FeSiAl magnetically soft alloy hollow microspheres

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Defence Technology（防务技术） 2018年第5期14卷 477-483页

作者： Xu-dong Cai Xiao-jun Jiang Wei Xie Jing-yang Mu De-fei Yin 63983 troops Wuxi214035China

FeSiAl magnetically soft alloy hollow microspheres(MSAHMs) were prepared by self-reactive quenching technology based on Fe + Si + AI + KNO_3 reactive systems, in order to obtain absorbents with light weight, low frequency and high efficiency. Firstly, twice-balling adhesive precursor method was used to obtain FeSiAl magnetically soft alloy agglomerate powders. Then agglomerate powders with the mesh number of 150-240, 240-325 and 325-400 were sprayed through the flame field into the quenching water. At last, FeSiAl MSAHMs with coarse(average at 86.97 μm), medium(average at 52.16 μm) and fine particles(average at 31.80 μm) were got. Effect of particle size on the phases and microwave absorption properties in low frequency band was studied by XRD and vector network analyzer. The results show that,Fe_3 Si_(0.7)Al_(0.3) and Fe_3 Si_(0.5)Al_(0.5) appear in the phase components of FeSiAl MSAHMs,which is important to improve the microwave absorption properties in low frequency. In addition, the real part(ε′) and imaginary part(ε″) of complex permittivity, the real part(μ′) and imaginary part(μ″) of complex permeability of FeSiAl MSAHMs all present the trend of fine particles > medium particles > coarse particles. The microwave absorption properties in low frequency are improved with the increasing of particle size, and the absorption peak moves to lower frequency range. The properties of fine particles are the best. Their matching thickness of samples is at 5 mm, and the minimum reflectivity is-43 dB at this thickness. The absorption frequency band lower than-10 dB is 4.6-7.6 GHz with a bandwidth of 3 GHz.

关键词： FeSiAl magnetically soft alloy Hollow microspheres Particle size Microwave absorption properties Low frequency

Application and Experiment on the Least-action Principle of Explosive Welding of Stainless Steel/Steel

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Journal of Iron and Steel Research International 2014年第6期21卷 625-629页

作者： Chang-gen SHI Yu WANG Si-jing LI Jun YOU PLA University of Science and Technology 78138 troops of PLA

In nature, many physical phenomena follow the least-action principle, which is also abided by the course of explosive welding of stainless steel/steel. The optimal welding interface can be obtained with the least explosive charge by theoretical analysis and interface test. The bonding energy can be acknowledged as the ＂action＂ in explosive welding. To minimize the bonding energy, these rules must be followed such as the lower limit of explosive charge, the upper limit of span and the explosive of critical explosion velocity. The principle of least-action is achieved in the course of explosive welding, and the interface will be optimum.

关键词： explosive welding least-action principle lower limit rule bonding interface

Detonation Mechanism in Double Vertical Explosive Welding of Stainless Steel/Steel

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Journal of Iron and Steel Research International 2015年第10期22卷 949-953页

作者： Chang-gen SHI Yu WANG Lin-sheng ZHAO Hong-bao HOU Yu-heng GE College of Field Engineering PLA University of Science and Technology 63981 troops PLA

One-dimensional detonation model and two-dimensional P-M （Prandtl-Meyer） expanding model of double vertical explosive welding were established. A one-dimensional formula of flyer plate velocity was obtained and the bending angle curve representing flying attitude of flyer plate in double vertical was deduced as well. Compared with single parallel explosive welding, the double vertical explosive welding combines two cladding plates in one explosion. Due to closed charging structure, the influence of rarefaction wave on the plate＇s surface in double vertical explosive welding is eliminated and explosion loading time and displacement are increased, resulting in the increase of flyer velocity and energy utilization rate by 1.3 times to 1.6 times in different mass ratios. The analysis of microstructure in bonding zone of double vertical cladding plate under traditional charging shows that there is a clear over-melting near the interface, which is in line with the conclusion of detonation mechanism.

关键词： explosive welding detonation mechanism double vertical interface bonding strength

An adaptive waveform-detection threshold joint optimization method for target tracking

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Journal of Central South University 2013年第11期20卷 3057-3064页

作者：王宏强夏洪恩程永强王璐璐 School of Electronic Science and Engineering National University of Defense Technology 66242 PLA troops

The joint optimization of detection threshold and waveform parameters for target tracking which comes from the idea of cognitive radar is investigated for the modified probabilistic data association(MPDA)*** transmitted waveforms and detection threshold are adaptively selected to enhance the tracking *** modified Riccati equation is adopted to predict the error covariance which is used as the criterion function,while the optimization problem is solved through the genetic algorithm(GA).The detection probability,false alarm probability and measurement noise covariance are all considered together,which significantly improves the tracking performance of the joint detection and tracking *** results show that the proposed adaptive waveform-detection threshold joint optimization method outperforms the adaptive threshold method and the fixed parameters method,which will reduce the tracking *** average reduction of range error between the adaptive joint method and the fixed parameters method is about 0.6 m,while that between the adaptive joint method and the adaptive threshold only method is about 0.3 *** error reduction occurs for the velocity error and acceleration error.

关键词： cognitive radar adaptive waveform selection target tracking joint optimization detection-tracking system

Improved acoustic localization method for projectile dropping point

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Chinese Journal of Acoustics 2021年第2期40卷 194-208页

作者： YU Guodong WANG Chunyang WANG Shizan ZHANG Yue LIU Xiaochen 63869 troops of PLA Baicheng 137001

This paper proposes an improved least squares acoustic source localization method using a sensor ***,according to the effect of wind velocity,direction,and temperature on sound velocity,the correction model of the observation is *** weight matrix is correct by the law of error propagation,after that,the least square method is used to give out localization *** that the existence of the gross error is possible,IGG3 robust model is integrated into the data processing to improve the anti-interference ability of the ***,the wrong observations *** by observing the residuals vector,and then the time series chaos question is solved by adjusting the ***,the effectiveness and feasibility of the proposed method are verified by the real *** results show that the improved least square localization method achieves the localization accuracy within4 *** proposed method can not only effectively reduce the influence of gross errors,but also deal with the time series chaos problem perfectly,and the reliability of the system can be *** research work may provide some references for the design and application of acoustic source localization equipment.

关键词： calculation. chaos correction

Dynamic stability of axially accelerating viscoelastic plates with longitudinally varying tensions

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Applied Mathematics and Mechanics(English Edition) 2016年第12期37卷 1647-1668页

作者： Youqi TANG Dengbo ZHANG Mohan RUI Xin WANG Dicheng ZHU School of Mechanical Engineering Shanghai Institute of Technology Third Maintenance Squadron People's Liberation Army 93256 Troops

The dynamic stability of axially accelerating plates is investigated. Longitudi- nally varying tensions due to the acceleration and nonhomogeneous boundary conditions are highlighted. A model of the plate combined with viscoelasticity is applied. In the viscoelastic constitutive relationship, the material derivative is used to take the place of the partial time derivative. Analytical and numerical methods are used to investigate summation and principal parametric resonances, respectively. By use of linear models for the transverse behavior in the small displacement regime, the plate is confined by a viscous damping force. The generalized Hamilton principle is used to derive the govern- ing equations, the initial conditions, and the boundary conditions of the coupled planar vibration. The solvability conditions are established by directly using the method of mul- tiple scales. The Routh-Hurwitz criterion is used to obtain the necessary and sufficient condition of the stability. Numerical examples are given to show the effects of related parameters on the stability boundaries. The validity of longitudinally varying tensions and nonhomogeneous boundary conditions is highlighted by comparing the results of the method of multiple scales with those of a differential quadrature scheme.

关键词： parametric resonance axially moving plate longitudinally varying tension nonhomogeneous boundary condition

ACUPUNCTURE TREATMENT FOR SPRAINS OF THE ANKLE JOINT IN 354 CASES

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Journal of Traditional Chinese Medicine 1990年第3期10卷 207-208页

作者：张福军苗玉民 PLA Hospital of 86515 troops

Sprains of the ankle joint is one of themost common soft tissue injuries,which isusually caused by a violent *** can lacerate the interarticular lig-aments and the tendon insertions aroundthe ankle *** treated 354 cases of thistype of injury with acupuncture,yielding aninspiring therapeutic *** MATERIALSOf the 354 cases in this series,291 caseswere injured for the first time,and 63

关键词： injured acupuncture ankle injuries violent tendon minutes suture medial yielding

Stability Robustness of Control System in Angular Metric

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Stability Robustness of Control System in Angular Metric

Initiation of vacuum breakdown and failure mechanism of the carbon nanotube during thermal field emission

第25届中国控制与决策会议

作者： Bin Liu Wei-fang Ci Bo-wen Huo School of Electrical and Information Engineering Northeast Petroleum University 91451 troops

ISBN: (纸本)9781467355339

The robust control theory based on -norm is the successful example of solving the robust control problem, which has become a fairly systematic theory. However, -norm can only be used to measure the distance between two stable systems not the unstable systems. Sometimes, it is not appropriate to measure the gap of two stable systems. A new metric, angular metric, is defined in linear spaces of real rational matrices, which can measure the uncertainties and describe the performance specifications of the robust control system. In the framework of this metric, robust stability margin is proposed to characterize the stability robustness of the closed-loop system. When both the plant and the controller have uncertainties simultaneously, we introduce the structural robust stability, and prove the necessary and sufficient conditions of the robust stability of the feedback control system.

关键词： Stability Robustness Unitarily Invariant Norm Angular Metric

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Chinese Physics B 2016年第4期25卷 206-213页

作者：蔡丹刘列巨金川赵雪龙周泓宇王潇 College of Optoelectric Science and Engineering National University of Defense Technology Changsha 410073 China 78010 PLA troops Chengdu 610000 China

The carbon nanotube （CNT）-based materials can be used as vacuum device cathodes. Owing to the excellent field emission properties of CNT, it has great potentials in the applications of an explosive field emission cathode. The falling off of CNT from the substrate, which frequently appears in experiments, restricts its application. In addition, the onset time of vacuum breakdown limits the performance of the high-power explosive-emission-cathode-based diode. In this paper, the characteristics of the CNT, electric field strength, contact resistance and the kind of substrate material are varied to study the parameter effects on the onset time of vacuum breakdown and failure mechanism of the CNT by using the finite element method.

关键词： carbon nanotube thermal field electron emission vacuum breakdown failure mechanism