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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 calibrated.Taking 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 process.The 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 sensitivity.The 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 ignition.The effects of impact velocity on sensitivity were analyzed and the critical local ignition impact velocity is determined as 4.0-4.5 m/s.The simulated results show that shear-crack friction heating is the dominant ignition mechanism.The region along the boundary of PBXs sample is the most hazardous regions where ignition first occur.The 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

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 motors.The 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 mechanism.SHPB 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 process.The results suggested that the mechanical responses and damage-ignition mechanism of the propellants were affected by the strain rates and crosslinking density.The damage-ignition degree is more intense and the reaction occurs earlier with the increase of strain rates.For propellant 1 with higher crosslinking density,the critical ignition strain rate is 4500 s^(-1).Two kinds of propellants show different ignition mechanism,i.***.crack generation,propagation and final fracture for propellant 1 while viscous shear flow for propellant 2.Meanwhile,the SEM images also reveal the difference of damage-ignition mechanism of the two kinds of propellants.Finally,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 conducted.The 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)technique.To further analyze the related mesoscale deformation mechanisms,a nonlinear thermoelastic-viscoplastic model was developed,which considers thermal activation and phonon drag dislocation slip mechanisms.The proposed model could well reproduce the measured thermal hardening behavior of Hugoniot elastic limit(HEL)of HMX single crystals.At elevated temperatures,the reduced dislocation mobility was observed,which stems from both phonon scattering and radiative damping effects.Comparatively speaking,radiative damping contributes less than phonon scattering to thermal hardening behavior.The calibrated model was further used to predict shock response of HMX single crystals with different thicknesses at different initial temperatures.Both the stress relaxation and elastic precursor decrease with thickness are mainly due to the rapid dislocation generation.These 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

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 treatment.These drugs are widely abused among the general public to increase lean weight and improve athletic performance.It has been reported that AAS use can produce many adverse effects,especially the occurrence of cardiovascular risk.Although there are many related studies,there has been no consensus on AAS use and cardiovascular risk.The present study was to review the effect of AAS on the cardiovascular system.Data sources:The data in this review were obtained from articles included in PubMed and the National Center for Biotechnology Information database.Study selection:Original articles,case reports,and systematic reviews about AAS were selected for the article.Results:The use/abuse of AAS is correlated with higher cardiovascular risks,and many AAS users/abusers had cardiovascular diseases.However,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 toxicity.Conclusion: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

基于GBDT的望奎县农田土壤有机碳主控因子研究

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中国环境科学 2024年第3期44卷 1407-1417页

作者：祝元丽冯向阳闫庆武吴子豪中国矿业大学公共管理学院江苏徐州221116 中国矿业大学矿区土地利用与生态安全研究中心江苏徐州221116 中国矿业大学中国资源型城市转型发展与乡村振兴研究中心江苏徐州221116

利用多源公开数据,针对于2012年搜集到的农田土壤有机碳(SOC)数据,通过梯度增强决策树(GBDT)探究SOC的主控因子,揭示SOC空间分异机理.选择国家商品粮食生产基地县和全国产量大县-望奎县作为研究区域,结果表明,GBDT模型相较于一元线性回... 详细信息

利用多源公开数据,针对于2012年搜集到的农田土壤有机碳(SOC)数据,通过梯度增强决策树(GBDT)探究SOC的主控因子,揭示SOC空间分异机理.选择国家商品粮食生产基地县和全国产量大县-望奎县作为研究区域,结果表明,GBDT模型相较于一元线性回归模型在所有的自变量上均具有更好的预测效果,总体的R^(2)为0.958,表明该模型能够很好地解释目标变量的变异;碱解氮、有效磷、气温、土壤微生物多样性、速效钾、土壤pH和降水量依次是影响有机碳含量最为显著的几个因素,其中碱解氮以33.85%的影响权重位居最高;7个环境协变量均观察到对SOC的阈值效应,且均具有两个阈值.研究发现任意两个变量都不是独立的,均存在相互作用的负值效应.表明环境变量对SOC含量的影响是一个复杂的交互作用,而不是简单的叠加.侧面证明了过度施肥并不会达到增加土壤肥力的作用,而会造成资源浪费和农田生态污染问题.

关键词：土壤有机碳农田梯度提升决策树主控因子黑土区非线性关系

Latest developments in EUV photoresist evaluation capability at Shanghai Synchrotron Radiation Facility

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Nuclear Science and Techniques 2023年第12期34卷 206-215页

作者： Zhen‑Jiang Li Cheng‑Hang Qi Bei‑Ning Li Shu‑Min yang Jun Zhao Zhi‑Di Lei Shi‑Jie Zhu Hao Shi Lu Wang yan‑qing wu Ren‑Zhong Tai Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China Shanghai Synchrotron Radiation Facility Shanghai 201204China ShanghaiTech University Shanghai 201210China Key Laboratory of Materials for High Power Lasers Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China College of Materials Science and Opto‑Electronic Technology University of Chinese Academy of SciencesBeijing 100083China Shanghai University Shanghai 200444China

Evaluating the comprehensive characteristics of extreme ultraviolet(EUV)photoresists is crucial for their application in EUV lithography,a key process in modern technology.This paper highlights the capabilities of the Shanghai Synchrotron Radiation Facility(SSRF)08U1B beamline in advancing this field.Specifically,it demonstrates how this beamline can create fringe patterns with a 15-nm half-pitch on a resist using synchrotron-based EUV lithography.This achievement is vital for evaluating EUV photoresists at the advanced 5-nm node.We provide a detailed introduction to the methods and experimental setup used at the SSRF 08U1B beamline to assess an EUV photoresist.A significant part of this research involved the fabrication of high-resolution hydrogen silsesquioxane mask gratings.These gratings,with an aspect ratio of approximately 3,were created using electron beam lithography on an innovative mask framework.This framework was crucial in eliminating the impact of zeroth-order light on interference patterns.The proposed framework propose offers a new approach to mask fabrication,particularly beneficial for achromatic Talbot lithography and multicoherent-beam interference applications.

关键词： Extreme ultraviolet photoresist Interference lithography High-resolution Electron beam lithography·Hydrogen silsesquioxane Grating

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

Peripheral leukocyte count and risk of bleeding in patients with non-valvular atrial fibrillation taking dabigatran: a real-world study

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Chinese Medical Journal 2019年第18期132卷 2150-2156页

作者： Wei Zhou Tao Wang Ling-Juan Zhu Ming-Hua Wen Li-Hua Hu Xiao Huang Chun-Jiao You Ju-Xiang Li yan-qing wu qing-Hua wu Hui-Hui Bao Xiao-Shu Cheng Center for Prevention and Treatment of Cardiovascular Diseases The Second Affiliated Hospital of Nanchang University Nanchang Jiangxi 330006 China Department of Cardiovascular Medicine The Second Affiliated Hospital of Nanchang University Nanchang Jiangxi 330006 China

Background: The association between peripheral leukocyte count and bleeding events in nonvalvular atrial fibrillation (NVAF) patients treated with dabigatran remains unclear. This study aimed to explore the association between leukocyte count and bleeding events after excluding other confounders in NVAF patients taking dabigatran. Methods: A total of 851 NVAF patients treated with dabigatran (110 mg bid) were recruited from 12 centers in China from February 2015 to December 2017. Follow-up was completed by May 2018. The exposure and outcome variables were leukocyte count measured at baseline and the number of bleeding events within the subsequent 6 months. Multivariate Cox proportional hazards models were constructed to analyze independent associations, and a Cox proportional hazards regression with cubic spline functions and smooth curve fitting (penalized spline method) was used to address nonlinearity between leukocyte count and bleeding. The inflection point was calculated using a recursive algorithm, and then a two-piecewise Cox proportional hazards model for both sides of the inflection point was constructed. Results: During 6-month follow-up, 87 participants occurred bleeding events. For every 1×10^9/L increase in leukocyte count, the risk of bleeding increased by 11%(hazard ratio [HR]: 1.11, 95% confidence interval [CI]: 0.99–1.25). The smooth curve showed nonlinear relationship between leukocyte count and bleeding events. The inflection point of the leukocyte count was 6.75×10^9/L. For leukocyte counts < 6.75×10^9/L, the HR (95% CI) was 0.88 (0.69–1.13), and for leukocyte counts ≥ 6.75×10^9/L, the HR (95% CI) was 1.28 (1.09–1.51). Conclusion: This study found a J-shaped association between baseline leukocyte count and risk of bleeding in NVAF patients treated with dabigatran.

关键词： Peripheral leukocyte count Bleeding Nonvalvular atrial fibrillation Threshold effect