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Defence Technology（防务技术） 2022年第9期18卷 1602-1621页

作者： Hai-jiao Xue yan-qing wu Kun yang Yi wu State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081China

Investigating the damage and ignition behaviors of polymer-bonded explosive(PBX) under a coupled impact and high-temperature loading condition is required for the safe use of charged PBXs. An improved combined microcrack and microvoid model(CMM) was developed for better describing the thermal effects of deformation, damage, and ignition responses of PBXs. The main features of the model under typical dynamic loadings(i.e. uniaxial tension and compression, and lateral confinement) at different initial temperature were first studied. And then the effects of temperature on impact-shear sensitivity of HMX-based PBXs were investigated. The results showed that the ignition threshold velocity of shear-crack hotspots exhibits an increase from 260 to 270 to 315-325 m/s when initial temperature increases from 301 to 348 K;and then the threshold velocity decreases to 290-300 m/s with the initial temperature continually increasing to 378 K. The predicted ignition threshold velocity level of the explosives under coupled impact and high temperature loading conditions were consistent with the experimental data.

关键词： PBX Thermal-mechanical coupling Numerical simulation Impact Sensitivity

Effect of interface behaviour on damage and instability of PBX under combined tension-shear loading

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Defence Technology（防务技术） 2023年第5期23卷 137-151页

作者： Quan-zhi Xia yan-qing wu Feng-lei Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China

To study the effect of interface behaviour on the mechanical properties and damage evolution of PBX under combined tension-shear loading, the present work establishes the numerical model of a PBX three-phase hybrid system, which introduces a nonlinear plastic damage cohesion model to study the mechanical response and damage process. The parameters in the model were fitted and *** the crack growth rate as the feature, the damage state in each stage was determined, and the damage instability criterion was given. The effects of interfacial tensile strength and shear strength on the damage process of PBX were studied. On this basis, serrated and hemispherical structures interface of PBX has been developed, which affects the damage process and instability during the loading *** results indicate that damage state response of PBX experiences the process of stable load bearing,unstable propagation, and complete failure. At the critical moment of instability, the overall equivalent effective strain of material reaches 3024 με and instability loading displacement reaches 0.39 mm. The increase of interfacial tensile strength and shear strength significantly inhibits the damage of PBX. The effect of interfacial shear strength on critical instability of PBX is approximately 1.7 times that of the interfacial tensile strength. Further, interface opening along the normal direction is the main damage form at the interface. Serrated and hemispherical rough interfaces can significantly inhibit propagation of cracks, and the load bearing capacity is improved by 22% and 9.7%, respectively. Appropriate improvement of the roughness of the interface structure can effectively improve the mechanical properties. It is significantly important to have a better understanding of deformation, damage and failure mechanisms of PBX and to improve our predictive ability.

关键词： PBX explosives Interface behaviour Damage Instability Crack propagation

Numerical simulation of drop weight impact sensitivity evaluation criteria for pressed PBXs

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Defence Technology（防务技术） 2023年第1期19卷 76-90页

作者： Hong-zheng Duan yan-qing wu Kun yang Feng-lei Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China

A thorough understanding of drop-weight impacted responses for polymer-bonded explosives(PBXs)is significant to evaluate their impact *** characteristics of the drop-weight impacted pressed PBXs including deforming,fracturing,forming a local high-temperature region and igniting,were simulated using a coupled mechanical-thermo-chemical model integrating micro-defects evolution.A novel evaluation method for impact sensitivity is established using the relation between the input kinetic energy and the output energy due to deformation,crushing energy,local hot spot energy and *** effects of impact velocity on sensitivity were analyzed and the critical local ignition impact velocity is determined as 4.0-4.5 m/*** simulated results show that shear-crack friction heating is the dominant ignition *** region along the boundary of PBXs sample is the most hazardous regions where ignition first *** propagation of stress wave in PBXs causes shear-crack hotspot and bulk temperature exhibiting an approximate 45°direction evolution path,which is the main reason that dominated damage-ignition region transits from the boundary to the central of sample.

关键词： Polymer-bonded explosives(PBXs) Drop weight impact Numerical simulation Sensitivity evaluation criterion Hotspot mechanism

Sharp Estimates of p-Adic Hardy and Hardy-Littlewood-Pólya Operators

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Acta Mathematica Sinica,English Series 2013年第1期29卷 137-150页

作者： Zun Wei FU qing yan wu Shan Zhen LU Department of Mathematics Linyi University School of Mathematical Sciences Beijing Normal University

In this paper we get the sharp estimates of the p-adic Hardy and Hard^Littlewood-Pdlya operators on L^q （｜x｜apdx）. Also, we prove that the commutators generated by the p-adic Hardy operators （Hardy-Littlewood-Pdl... 详细信息

关键词： p-Adic Hardy operator p-Adic Hardy-Littlewood-P61ya operator central BMO function,Herz space

Experimental investigations of mechanical and reaction responses for drop-weight impacted energetic particles

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Acta Mechanica Sinica 2017年第1期33卷 65-70页

作者： Xiao-Wei Bao yan-qing wu Ming-yang Wang Feng-Lei Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China

Low-velocity drop-weight impact experiments on individual and multiple Cyclotetramethylene tetranitramine (HMX) energetic particles were performed using a modified drop-weight machine equipped with high-speed photography components. Multiple particles experienced more severe burning reactions than an individual particle. Comparisons between impacted salt and HMX particle show that jetting in HMX is mainly due to the motion of fragmented particles driven by gaseous reaction products. Velocity of jetting, flame propagation, and area expansion were measured via image processing, making it possible to quantify the chemical reaction or mechanical deformation violence at different stages.

关键词： HMX energetic particle Drop-weight impact High-speed photography Ignition and combustion Jetting

Damage-ignition mechanism studies on modified propellant with different crosslinking density under dynamic loading

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Defence Technology（防务技术） 2023年第10期28卷 155-164页

作者： Hong-zheng Duan yan-qing wu Xiao Hou Kun yang Feng-lei Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081PR China The Fourth Institute of China Aerospace Science and Technology Corporation Xi'an710025PR China

The study of high-energy and low-vulnerability propellants is important for the power performance and safety of solid propellant rocket *** modified split Hopkinson pressure bar(SHPB)tests are performed on two kinds of propellant with different crosslinking density to study the dynamic mechanical responses and damage-ignition *** apparatus is equipped with a highperformance infrared camera and high-speed camera to capture the deformation,damage-ignition feature and temperature evolution images in the impact *** results suggested that the mechanical responses and damage-ignition mechanism of the propellants were affected by the strain rates and crosslinking *** damage-ignition degree is more intense and the reaction occurs earlier with the increase of strain *** propellant 1 with higher crosslinking density,the critical ignition strain rate is 4500 s^(-1).Two kinds of propellants show different ignition mechanism,*** generation,propagation and final fracture for propellant 1 while viscous shear flow for propellant ***,the SEM images also reveal the difference of damage-ignition mechanism of the two kinds of ***,the ignition mechanism under different strain rates and critical ignition strain rate of propellants are further explained by the theoretical calculation of temperature variations.

关键词： The modified propellants Dynamic loading Mechanical property Damage-ignition mechanism Experimental and theoretical calculation

Shock response of cyclotetramethylene tetranitramine(HMX)single crystal at elevated temperatures

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Defence Technology（防务技术） 2023年第3期21卷 147-163页

作者： Kai Ding Xin-Jie Wang Zhuo-Ping Duan yan-qing wu Feng-Lei Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China

To investigate the shock response of cyclotetramethylene tetranitramine(HMX)single crystals at elevated temperatures(below the phase transition point),plate impact experiments at elevated temperatures were designed and *** HMX/window interface particle velocities at temperatures of 300 K,373 K,and 423 K were measured by the velocity interferometry system for any reflector(VISAR)*** further analyze the related mesoscale deformation mechanisms,a nonlinear thermoelastic-viscoplastic model was developed,which considers thermal activation and phonon drag dislocation slip *** proposed model could well reproduce the measured thermal hardening behavior of Hugoniot elastic limit(HEL)of HMX single *** elevated temperatures,the reduced dislocation mobility was observed,which stems from both phonon scattering and radiative damping *** speaking,radiative damping contributes less than phonon scattering to thermal hardening *** calibrated model was further used to predict shock response of HMX single crystals with different thicknesses at different initial *** the stress relaxation and elastic precursor decrease with thickness are mainly due to the rapid dislocation *** insights shed light on the interplay between dislocation motion and dislocation generation in thermal hardening behavior,stress relaxation,and elastic precursor decay,which serves to reveal the mesoscale deformation mechanisms at elevated temperatures.

关键词： deformation elevated dislocation

Interleukin-21 gene polymorphisms and chronic hepatitis B infection in a Chinese population

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World Journal of Gastroenterology 2015年第14期21卷 4232-4239页

作者： Jia-yan Yao Kang Chao Min-Rui Li yan-qing wu Bi-Hui Zhong Department of Gastroenterology The First Affiliated Hospital of Sun Yat-Sen University

AIM: To investigate the relationship between inter-leukin-21(IL21) gene polymorphisms and chronic hepatitis B virus(HBV) infection in a Chinese ***: In this case-control study, 366 Chinese HBV-infected patients were recruited and divided into hepatocellular carcinoma(HCC; n = 94) and non-HCC(n = 272) groups at The First Affiliated Hospital of Sun Yat-Sen University, from April 2009 to December *** the non-HCC group, the patients were classified into three clinical subsets, 76 patients had chronic hepatitis B, 101 were HBV carriers and 95 patients had HBV-related *** hundred eight unrelated healthy controls were also *** DNA was extracted from peripheral *** nucleotide polymorphisms(SNPs) rs13143866, rs2221903, and rs907715 were subsequently genotyped using the SNaP shot SNP ***: There were no significant differences in allele and genotype frequencies of SNPs rs13143866, rs2221903, and rs907715 between chronic HBVinfected patients and control ***, no significant differences were found in the frequencies of all alleles and genotypes between the HCC group and the non-HCC ***, in the subgroup analysis, IL21 rs13143866 genotype AA frequency in the HBV carrier group was higher than in controls(OR = 6.280, 95%CI: 1.238-31.854; P = 0.019), and the effect of the recessive model(AA vs GG + GA, OR = 6.505, 95%CI: 1.289-32.828) was observed in the HBV carrier ***21 rs2221903 genotype TC frequency in the HBV carrier group was higher than in controls(OR = 1.809, 95%CI: 1.043-3.139; P = 0.035).In the haplotype analysis, the ATA haplotype(rs13143866, rs2221903, and rs907715) of IL21 was more frequent in the HCC group than in the non-HCC group(0.165 vs 0.104, P = 0.044; OR = 1.700, 95%CI: 1.010-2.863).CONCLUSION: Genotypes rs13143866 AA and rs2221903 TC are risk factors for carrying HBV; ATA haplotype increases the risk of HBV-related HCC onsetin a Chinese population.

关键词： Chinese population Chronic hepatitis B virus infec

Anabolic-androgenic steroids and cardiovascular risk

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Chinese Medical Journal 2019年第18期132卷 2229-2236页

作者： Jian-Di Liu yan-qing wu Department of Cardiology The Second Affiliated Hospital of Nanchang University Nanchang Jiangxi 330006 China

Objective:Anabolic-androgenic steroids (AAS) represents a group of synthetic testosterone derivatives that play an important role in clinical *** drugs are widely abused among the general public to increase lean weight and improve athletic *** has been reported that AAS use can produce many adverse effects,especially the occurrence of cardiovascular *** there are many related studies,there has been no consensus on AAS use and cardiovascular *** present study was to review the effect of AAS on the cardiovascular *** sources:The data in this review were obtained from articles included in PubMed and the National Center for Biotechnology Information *** selection:Original articles,case reports,and systematic reviews about AAS were selected for the ***:The use/abuse of AAS is correlated with higher cardiovascular risks,and many AAS users/abusers had cardiovascular ***,there are many confounding factors in the studies that explored the causality between AAS intake and disease development,and additional studies are required to determine AAS ***:AAS produces toxic effects on the cardiovascular system,and it is necessary to ensure that more people know this about AAS,including medical personnel.

关键词： Anabolic-androgenic steroid Cardiovascular risk Toxicity effects

Toward path reliability by using adaptive multi-path routing mechanism for multimedia service in mobile Ad-hoc network

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The Journal of China Universities of Posts and Telecommunications 2010年第1期17卷 93-100页

作者： ZHEN yan,wu Mu-qing,wu Da-peng,ZHANG Qin-juan,XU Chun-xiu Broadband Communication Network Laboratory,Beijing University of Posts and Telecommunications,Beijing 100876,China Broadband Communication Network Laboratory Beijing University of Posts and Telecommunications Beijing 100876 China

Traditional multi-path routing mechanisms aim to establish complete node or link disjoint paths. However, under some circumstances if multiple paths cannot be established based on the current network topology, the traditional multi-path routing mechanism will degenerate into single path routing mechanism, thus the advantages of multi-path routing cannot be exhibited. To enhance the end-to-end path reliability, an adaptive multi-path routing mechanism with path segment is proposed, in which multi-path can be established at part of the end-to-end path. In this way the reliability of the path can be enhanced. This path segment mechanism can divide the end-to-end path into several short segments, and a parallel forwarding mechanism is proposed for guaranteeing the quality of service of multimedia services over the wireless network. Simulations show that the network performance metrics such as the packet delivery ratio, the end-to-end delay and the number of route discoveries are all improved by using the adaptive multi-path routing mechanism.

关键词： mobile Ad-hoc networks multi-path routing reliability parallel forwarding path segment