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Research on the quasi-isentropic driving model of aluminized explosives in the detonation wave propagation direction

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Defence Technology（防务技术） 2024年第2期32卷 596-618页

作者： Hongfu Wang yan Liu Fan Bai Chao He Yingliang Xu qiang Zhou Chuan xiao Fenglei Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China China Research and Development Academy of Machinery Equipment Beijing100089China Beijing Institute of Technology Chongqing Innovation Center Chongqing401120China

Taking CL-20(Hexanitrohexaazaisowurtzitane)-based aluminized explosives with high gurney energy as the research object, this research experimentally investigates the work capability of different aluminized explosive formulations when driving metal flyer plates in the denotation wave propagation *** research results showed that the formulations with 43 μm aluminum(Al) powder particles(The particle sizes of Al powder were in the range of 2~43 μm) exhibited the optimal performance in driving flyer plates along the denotation wave propagation direction. Compared to the formulations with Al powder 13 μm, the formulations with Al powder 2 μm delivered better performance in accelerating metal flyer plates in the early stage, which, however, turned to be poor in the later stage. The CL-20-based explosives containing 25% Al far under-performed those containing 15% Al. Based on the proposed quasi-isentropic hypothesis, relevant isentropy theories, and the functional relationship between detonation parameters and entropy as well as Al reaction degree, the characteristic lines of aluminized explosives in accelerating flyer plates were theoretically studied, a quasi-isentropic theoretical model for the aluminized explosive driving the flyer plate was built and the calculation methods for the variations of flyer plate velocity, Al reaction degree, and detonation product parameters with time and axial positions were developed. The theoretical model built is verified by the experimental results of the CL-20-based aluminized explosive driving flyer plate. It was found that the model built could accurately calculate the variations of flyer plate velocity and Al reaction degree over time. In addition, how physical parameters including detonation product pressure and temperature varied with time and axial positions was identified. The action time of the positive pressure after the detonation of aluminized explosives was found prolonged and the downtrend of the temperature was

关键词： Aluminized explosive Flyer plate experiment Quasi-isentropic theoretical model Al reaction Driving characteristics

Awareness of Tobacco-Related Health Hazards among Adults in China

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Biomedical and Environmental Sciences 2010年第6期23卷 437-444页

作者： yan yanG JI-JIANG WANG CONG-xiao WANG qiang LI GONG-HUAN yanG National Office for Tobacco Control China Center for Disease Control and Prevention Beijing 100050 China Universtty of Waterloo Waterloo Ontario Canada

Objective To determine the level of awareness of the hazards of tobacco smoking and secondhand smoke inhalation among adults in China. Methods Household surveys were conducted with a total of 13 354 respondents aged 15 years or over from 100 counties of 28 Chinese provinces using a stratified multi-stage geographically clustered sample design. Results The findings revealed that 81.8% of the population was aware that smoking causes serious diseases, and 27.2% and 38.7% were aware that smoking causes stroke and heart attack, respectively. Only 64.3% of respondents were aware that secondhand smoke can cause serious diseases, and 27.5%, 51.0%, and 52.6% were aware that secondhand smoke causes heart disease in adults, lung disease in children and lung cancer in adults, respectively. Awareness regarding smoking-related hazards across all participants was significantly associated with several factors, including gender, smoking status, urban/rural residency, education level and exposure to tobacco control publicity in the last 30 days. Awareness regarding tobacco-related hazards in smokers was significantly associated with urban/rural residency, education level, exposure to tobacco control publicity in the last 30 days, and physician＇s advice. Awareness relating to the hazards of inhaling secondhand smoke was associated with smoking status, urban/rural residency, age, education level, and exposure to tobacco control publicity in the last 30 days. Medical professionals were found to know more about the health hazards of tobacco compared with people in other types of employment. Conclusions Overall awareness of the health hazards of tobacco has improved in the last 15 years in China, but is still relatively poor. Improved means of communicating information and more effective warning labels on cigarette packaging are necessary for increasing public awareness of tobacco hazards, particularly among rural residents and people with less education.

关键词： Smoking Secondhand smoke Awareness Knowledge

The Two-step Reverse Martensitic Transformations of TiNi Shape Memory Alloy Based on Solution-treatment and Aging

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Chinese Journal of Aeronautics 2006年第B12期19卷 198-201页

作者： JIANG Da-qiang CUI Li-shan ZHENG yan-jun JIANG xiao-hua Department of Materials Science and Engineering China University of Petroleum Beijing 102249 China

A TiNi-alloy is solution-treated in a vacuum furnace of 6.7×10^-3 Pa at 1 223 K for 3.6 ks, and then aged at 773 K for 1.8 ks. The differential scanning calorimetry （DSC） measurements show that after the heat-treatment, takes place a two-step reverse Martensitic transformation, from which results the two-stage recovery strain in a prestrained Martensitic TiNi-alloy wire during heating. The Vickers microhardness indentation test in cross-sectional areas of the TiNi-alloy wire indicates the compositional heterogeneity between its surface layers and its inside. The fact that the sizes of the indentation in surface layers smaller than those in the inside bears witness to the existence of slightly harder surface layers. It is believed that these phenomena are related to the compositional fluctuation caused by the evaporation and oxidization of Ti-element during the solution-treatment and heterogeneity formed during the subsequent aging treatment.

关键词： shape memory alloy (SMA) TiNi solution-treatment heterogeneity

New insights into the functions and localization of the homeotic gene CDX2 in gastric cancer

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World Journal of Gastroenterology 2014年第14期20卷 3960-3966页

作者： Lin-Hai yan Wei-Yuan Wei Yu-Bo Xie qiang xiao Department of Surgery The First Affiliated Hospital of Guangxi Medical University Department of Anesthesiology The First Affiliated Hospital of Guangxi Medical University

Gastric cancer is one of the most frequent cancers, and it ranks the third most common cancer in China. The most recently caudal-related homeobox transcription factor 2 (CDX2) is expressed in a large number of human gastrointestinal cancers. In addition, gastric epithelial cell mutations in CDX2 result in tumor promotion, which is characterized by cellular drug resistance and a high proclivity for developing cancer. A series of publications over the past years suggests a mechanism by which CDX2 overexpression results in multidrug resistance. CDX2 appears to forward control regenerating IV and the multidrug resistance 1 expression signaling pathway for regulation of cell drug resistance.

关键词： Caudal-related homeobox transcription factor 2 Gastric cancer Intestinal metaplasia Apoptosis Drug resistance

Science and Technology Backyard: A novel approach to empower smallholder farmers for sustainable intensification of agriculture in China

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Journal of Integrative Agriculture 2019年第8期18卷 1657-1666页

作者： JIAO xiao-qiang ZHANG Hong-yan MA Wen-qi WANG Chong LI xiao-lin ZHANG Fu-suo Center for Resources Environment and Food Security Department of Plant Nutrition/Key Laboratory of Plant-Soil InteractionsMinistry of Education China Agricultural University Beijing 100193 P.R.China College of Resources and Environment Science Hebei Agricultural University Baoding 071001 P.R.China

Sustainable feeding of the growing population in China without ecological destabilization is a grand challenge. In this populous country where agriculture is dominated by smallholder farming, developing innovative technology and translating scientific knowledge into action for smallholder farmers is a crucial step in addressing this challenge. Here, we present a novel approach for technology innovation and dissemination to achieve sustainable intensification in the fields of smallholder farmers. The Science and Technology Backyard(STB) is a hub in a rural area that links knowledge with practices to promote technology innovation and exchange. In this study, the framework and functions of STB are introduced, and the key implications for sustainable intensification across millions of smallholder farmers are explicitly stated:(i) develop innovative technology based on stated demands of farmers;(ii) disseminate technology by innovative social service models though combined top-down approaches with bottom-up measures to enable smallholders in rural areas. This paper provides a perspective on transformation of small-scale agriculture toward sustainable intensification in China and useful knowledge applicable to other developing countries.

关键词： smallholder farmers sustainable intensification technology innovation technology transfer Science and Technology Backyard

Magnetoacoustic position imaging for liquid metal in animal interstitial structure

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Chinese Physics B 2020年第5期29卷 346-353页

作者： xiao-He Zhao Guo-qiang Liu Hui Xia yan-Hong Li Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Magnetoacoustic tomography with magnetic induction(MAT-MI),as a new kind of in-vivo imaging method,has potential application value in interstitial fluid *** this paper,we propose the application of MAT-MI with liquid metal serving as a tracer of the interstitial structure to study its fluid behavior,and use it to implement the positional imaging of the spatial distribution of liquid *** to the particularity of liquid metal magnetoacoustic pressure(MAP)signals,we propose an envelope analysis method to extract the rising edge of the amplitude envelope of the detected waveform as effective position *** for the first time,we propose the method of superpositing pixel matrix to achieve the position imaging of liquid ***,the positional imaging of the liquid metal sample embedded in the gel is achieved to have relatively accurate *** study provides a method of effectively extracting data and implementing the position imaging for liquid metal in the interstitial structure in the frame of MAT-MI.

关键词： magnetic acoustic tomography with magnetic induction(MAT-MI) liquid metal interstitial structure position imaging

Up-conversion of Nd^(3+)/Yb^(3+)/Tm^(3+) tri-doped CaTeO3 compound under excitation of 808 nm

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Rare Metals 2021年第4期40卷 1008-1013页

作者： Zhong-qiang Ye Si-Guo xiao xiao-Liang yang School of Physics and Optoelectronics Xiangtan UniversityXiangtan 411105China

Nd^(3+)/Yb^(3+)/Tm^(3+) tri-doped CaTeO3 compounds were prepared by a solid-state reaction *** blue up-conversion(UC) luminescence at around 476 nm,which corresponds to the Tm^(3+):^(1)G_(4)→^(3)H_(6) transition,was observed under 808-nm *** Nd^(3+)→Yb^(3+)→Tm^(3+) energy transfer process was responsible for the strong blue up-conversion emission in the tri-doped *** Tm^(3+) blue up-conversion emission intensity was strongly dependent on the concentrations of Yb^(3+) and Nd^(3+).The possible up-conversion mechanisms for the Nd^(3+)/Yb^(3+)/Tm^(3+) tri-doped CaTeO_(3) phosphor are discussed,based on the Nd^(3+) and Yb^(3+) concentration-dependent UC spectra,near-infrared luminescence spectra and luminescence decay curves.

关键词： Up-conversion Tellurite 808 nm Energy transfer

Design and Analysis of a Multi-Legged Robot with Pitch Adjustive Units

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Chinese Journal of Mechanical Engineering 2021年第3期34卷 226-242页

作者： qiang Ruan Jianxu Wu yan-an Yao Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control TechnologyMinistry of EducationBeijing Jiaotong UniversityBeijing 100044China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China

The paper proposes a novel multi-legged robot with pitch adjustive units aiming at obstacle *** only 6 degrees of freedom,the robot with 16 mechanical legs walks steadily and surmounts the obstacles on the complex *** leg unit with adjustive pitch provides a large workspace and empowers the legs to climb up obstacles in large sizes,which enhances the obstacle surmounting *** pitch adjustment in leg unit requires as few independent adjusting actuators as *** on the kinematic analysis of the mechanical leg,the biped and quadruped leg units with adjustive pitch are analyzed and *** configuration of the robot is designed to obtain a compact structure and pragmatic *** uncertainty of the obstacle size and position in the surmounting process is taken into consideration and the parameters of the adjustments and the feasible strategies for obstacle surmounting are *** the 3D virtual model and the robot prototype are built and the multi-body dynamic simulations and prototype experiments are carried *** results from the simulations and the experiments show that the robot possesses good obstacle surmounting capabilities.

关键词： Mechanical leg Multi-legged robot Obstacle surmounting Adjustive pitch Leg unit

Polymeric partners breathe together: using gas to direct polymer self-assembly via gas-bridging chemistry

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Science China Chemistry 2022年第7期65卷 1401-1410页

作者： Zehao Gong Yixin Wang qiang yan State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan University200433China

The quest for a general and facile way to regulate polymer self-assembled nanostructures with low-to high-order ergodicity is an eternal theme in soft nanoparticle fabrication. Here we present an unprecedented gas-bridging strategy that allows to use gas to direct polymer self-assembly in continuous and tunable manners. Such system comprises a partner of frustrated Lewis polymers with bulky Lewis acid and base groups. They can together “breathe in” external gases to form gas-bridged structures between the two complementary moieties, which drive their mutual complexation and assemble into polymer nanoparticles of diverse geometries and dimensionalities. This strategy is applicable to a broad family of gas substances including but not limited to carbon oxides, nitrogen oxides, sulfur oxides, and even olefins;moreover, tailoring gas types and levels can dictate distinct assembling evolutionary pathways and deformable behaviors among spherical, fibrous, polymersomal, tubesomal and cubosomal morphologies. We also discover that the gas-based bonding chemistry is the mechanistic basis underlying the phase transitional control and phase window regulation. This will open a new direction of making bespoke polymer nanostructures with gas.

关键词： gas-bridging bond Lewis pair polymer dynamic covalent chemistry self-assembly tunable nanostructure

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