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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

Predictable component analysis of a system based on nonlinear error information entropy

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Science China Earth Sciences 2017年第3期60卷 501-507页

作者： LI AiBing ZHANG LiFeng LI XinDong LI Wang WANG Bo No.96631 troops of pla Beijing 102208China College of Meteorology and Oceanography PLA University of Science and TechnologyNanjing 211101China

Based on the theory of information entropy concerning nonlinear errors, the growth rules for the nonlinear errors of the Lorenz system and its predictable components are studied. The results show that the impact of the uncertainties, both in the initial error and in the system itself, needs to be considered in a quantitative estimation of the system predictability. The nonlinear error growth is related to the magnitude of the initial error, and to the spatial distribution of the initial error vectors. Even if these initial errors have the same magnitude but different directions, there are also differences in the nonlinear error growth. The predictability of nonlinear error growth is related to the error component, but not related to the ratio of these components. The component with the highest/lowest rate of enntribution does not necessarily have the greatest/least predictability. The different components have different predictabilities, and in different time periods, the different predictable components also have different predictabilities.

关键词： Nonlinear error Information entropy Predietable component Lorenz system

Degree dependence entropy descriptor for complex networks

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Advances in Manufacturing 2013年第3期1卷 284-287页

作者： Xiang-Li Xu Xiao-Feng Hu Xiao-Yuan He Department of Information Operation and Command Training NDU of PLA No.65047 troops of pla

In order to supply better accordance for mod eling and simulation of complex networks, a new degree dependence entropy （DDE） descriptor is proposed to describe the degree dependence relationship and corre sponding characteristic in this paper. First of all, degrees of vertices and the shortest path lengths between all pairs of ,ertices are computed. Then the degree dependence matrices under different shortest path lengths are con structed. At last the DDEs are extracted from the degree dependence matrices. Simulation results show that the DDE descriptor can reflect the complexity of degree dependence relationship in complex networks; high DDE indicates complex degree dependence relationship; low DDE indicates the opposite one. The DDE can be seen as a quantitative statistical characteristic, which is meaningful for networked modeling and simulation.

关键词： Degree dependence matrix Degreedependence entropy (DDE) - Entropy Complex networks

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

The Interdecadal Changes of South Pacific Sea Surface Temperature in the Mid-1990s and Their Connections with ENSO

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Advances in Atmospheric Sciences 2014年第1期31卷 66-84页

作者： LI Gang LI Chongyin TAN Yanke BAI Tao Institute of Meteorology and Oceanography PLA University of Science and Technology LASG Institute of Atmospheric Physics Chinese Academy of Sciences No. 94162 troops of pla

The characteristic changes of South Pacific sea surface temperature anomalies （SSTAs） for the period January 1979 to December 2011, during which the 1990s Pacific pan-decadal variability （PDV） interdecadal regime shifts occurred, were examined. Empirical Orthogonal Function （EOF） analysis was applied to the monthly mean SSTA for two sub-periods： January 1979 to December 1994 （P 1） and January 1996 to December 2011 （P2）. Both the spatial and temporal features of the leading EOF mode for P1 and P2 showed a remarkable difference. The spatial structure of the leading EOF changed from a tripolar pattern for P 1 （EOF-P 1） to a dipole-like pattern for P2 （EOF-P2）. Besides, EOF-P 1 （EOF-P2） had significant spectral peaks at 4.6 yr （2.7 yr）. EOF-P2 not only had a closer association with E1 Nifio-Southern Oscillation （ENSO）, but also showed a faster response to ENSO than EOF-P1 based on their lead-lag relationships with ENSO. During the development of ENSO, the South Pacific SSTA associated with ENSO for both PI and P2 showed a significant eastward propagation. However, after the peak of ENSO, EOF-P1 showed a stronger persistence than EOF-P2, which still showed eastward propagation. The variability of the SSTA associated with the whole process of ENSO evolution during P1 and the SSTA associated with the development of ENSO during P2 support the existence of ocean-to-atmosphere forcing, but the SSTA associated with the decay of ENSO shows the phenomenon of atmosphere-to-ocean forcing.

关键词： ENSO South Pacific abrupt change of climate air-sea interaction

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

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

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

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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

Maintenance and Sudden Change of a Strong Elevated Ducting Event Associated with High Pressure and Marine Low-Level Jet

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Journal of Meteorological Research 2020年第6期34卷 1287-1298页

作者： Zhichao LIANG Juli DING Jianfang FEI Xiaoping CHENG Xiaogang HUANG College of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101 296746 troops of pla Korla 841000

Capture of a strong elevated ducting event,especially its maintenance and sudden change,is of great value to airborne radar to achieve its beyond-the-line-of-sight ***,the knowledge is not easily accessible over the open ocean and hence very *** the Air–Sea Interaction Survey(ASIS)over the western North Pacific(WNP)in May 2016,a strong elevated ducting event with a long-life period and sudden change in its evolution was *** from the ASIS,images from the Himawari-8 satellite,reanalysis data from the ECMWF,and Weather Research and Forecasting(WRF)model,were used to analyze the maintenance and sudden change of this strong ducting event,together with the model performance on simulating *** results showed that the maintenance of strong elevated ducts,with their tops ranging from 750 to 1050 m and average strength of approximately 38 M units,was caused by a strong dry air mass capping over the wet marine atmospheric boundary layer(MABL),together with the subsidence inversion associated with high *** WRF model performs well in simulating ***,a sudden increase in duct height with a slight decrease of strength was recorded by the subsequent GPS radiosonde,which was finally contributed to the mechanical turbulent inversion and hydrolapse associated with the marine low-level jet(MLLJ).The height of the maximum horizontal wind speed(Umh)of the MLLJ corresponds well with the bottom of the trapping ***,these jet-relevant ducts are generally weak and it is difficult to accurately simulate them by using the mesoscale numerical model,since the wind-shear produced eddies are too small to be properly parameterized.

关键词： atmospheric ducts elevated ducts marine atmospheric boundary layer(MABL) low-level jet numerical simulation