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Crystal phase control and ignition properties of HNS/CL-20 composite microspheres prepared by microfluidics combined with emulsification techniques

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Particuology 2024年第2期85卷 241-251页

作者： Yi Liu Yunyan Guo Rui Zhu Jinqiang Zhou Zhengxu Lin Kai Han Chongwei An Jingyu Wang Bidong Wu School of Environment and Safety engineering North University of ChinaTaiyuan030051China School of engineering Beijing Institute of TechnologyBeijing100081China Shanxi Province Ultrafine Powder engineering Technology research center Taiyuan030051China

Improved controllability and energy density of ignition agents are of great significance for the devel-opment of energetic composite materials.In this study,droplet microfluidics and emulsification tech-niques were combined to prepare HNS/CL-20 composite microspheres with polyglycidyl azide polymer(GAP)as the binder.The influence of binder content on the morphology of microspheres was investi-gated,and the microspheres were characterized and tested for particle size,crystal structure,thermal decomposition,dispersibility,mechanical sensitivity,combustion behavior and detonation performance.The results showed that microspheres prepared with a binder content of 3%had higher sphericity and particle size uniformity.The microspheres retained the crystal structure of both HNS and CL-20(ε-type).Compared with raw HNS,the microspheres had higher apparent activation energy,better safety per-formance,and good dispersibility.The ignition experiments and detonation performance tests show that HNS/CL-20 composite microspheres have excellent ignition performance,obvious combustion flame,and significant energy release effects,which are expected to achieve high energy and high-speed response of the igniter,thus improving the ignition reliability in special environments or systems.

关键词： Droplet microfluidics Emulsification technology Energetic materials Composite microspheres Crystal phase control Ignition

The reaction mechanism and interfacial crystallization of Al nanoparticle-embedded Ni under shock loading

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Defence Technology（防务技术） 2024年第3期33卷 114-124页

作者： Yifan Xie Jian-Li Shao Rui Liu Pengwan Chen State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Explosion Protection and Emergency Disposal Technology engineering research center of the Ministry of Education Beijing100039China

The shock-induced reaction mechanism and characteristics of Ni/Al system,considering an Al nanoparticle-embedded Ni single crystal,are investigated through molecular dynamics simulation.For the shock melting of Al nanoparticle,interfacial crystallization and dissolution are the main characteristics.The reaction degree of Al particle first increases linearly and then logarithmically with time driven by rapid mechanical mixing and following dissolution.The reaction rate increases with the decrease of particle diameter,however,the reaction is seriously hindered by interfacial crystallization when the diameter is lower than 9 nm in our simulations.Meanwhile,we found a negative exponential growth in the fraction of crystallized Al atoms,and the crystallinity of B2-NiAl(up to 20%)is positively correlated with the specific surface area of Al particle.This can be attributed to the formation mechanism of B2-NiAl by structural evolution of finite mixing layer near the collapsed interface.For shock melting of both Al particle and Ni matrix,the liquid-liquid phase inter-diffusion is the main reaction mechanism that can be enhanced by the formation of internal jet.In addition,the enhanced diffusion is manifested in the logarithmic growth law of mean square displacement,which results in an almost constant reaction rate similar to the mechanical mixing process.

关键词： Shock-induced reaction Molecular dynamics simulations Interfacial crystallization Reaction mechanism

Impact of Polymer Matrix on Polymer Mechanochromism from Excited State Intramolecular Proton Transfer

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Chinese Journal of Chemistry 2024年第6期42卷 611-616页

作者： Yu Wu Xin Cheng Huan Hu Shui Hu Zhimin Ma Zhiyong Ma beijing Advanced Innovation center for Soft Matter Science and engineering Beijing State Key Laboratory of Organic-Inorganic CompositesCollege of Chemical EngineeringBeijing University of Chemical TechnologyBeijing100029 China center of Advanced Elastomer Materials College of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing100029 China College of engineering Peking UniversityBeijing100871 China

Mechanochromic polymers based on non-covalent changes have attracted much attention recently.Herein,we report the impact of inter/intramolecular hydrogen bonds on polymer mechanochromism from the excited state intramolecular proton transfer (ESIPT) process.PhMz-NH2-OH and PhMz=2A are designed and obtained by simple and high-yield synthesis,and are connected into polyurethane and poly(methyl acrylate-co-2-ethylhexyl acrylate),respectively.In the initial state,the PhMz-NH2-OH@PU sample shows blue fluorescence from the excited enol form (E*) excitons,owing to intermolecular hydrogen bonds that interrupt the ESIPT reactions but the PhMz=2A@PMA-2-EA sample expresses cyan fluorescence belonging to the excited keto form (K*) emission,implying that the intramolecular hydrogen bonds matter.Furthermore,under stretching,external force can tune the emission of the PhMz=2A@PMA-2-EA sample from K* to E* state.Though external force can putatively still promote a bond rotation,ESIPT reactions remain equivalently interrupted in both the relaxed and stressed states in a hydrogen-bond donating environment.DFT calculation confirms the force-induced increase in dihedral angle for the transition of ESIPT-on/off.Thus,PhMz-NH2-OH@PU and PhMz=2A@PMA-2-EA showed disparate initial ESIPT states and further different responses/sensitivity to force.This study reports a novel and efficient strategy for enriching mechanochromic investigation and extending the applications of ESIPT reactions.

关键词： Polymer mechanochromism Excited state intramolecular proton transfer Hydrogen bonding Supramolecular chemistry Elastomers

Carbon-based supports for the electrocatalysis under industrially relevant conditions

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Science China Chemistry 2024年第4期67卷 1051-1055页

作者： Xue Yang Xianrui Gu Yang Song Guolin Hou Cheng Wang Lichen Liu Wei Lin center for Renewable Energy SINOPEC Research Institute of Petroleum ProcessingBeijing 100083China engineering research center of Advanced Rare Earth Materials Department of ChemistryTsinghua UniversityBeijing 100084China

1 Introduction.Carbon materials are ideal catalyst supports for functional metal components due to their appropriate physicochemical characteristics,such as high surface areas,tunable pore structures,variable morphologies and versatile surface properties based on chemical modifications,low cost and facile preparations from diverse precursors[1,2].

关键词： versatile facile supports

Hydrogen bond-bridged phosphorene flexible film for photodynamic inhibiting Staphylococcus aureus

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Nano research 2024年第6期17卷 5461-5468页

作者： Ziyu Wei Wenting Li Zhifang Liu Yongfa Zhu Huaqiang Cao Department of Chemistry Engineering Research Center of Advanced Rare Earth MaterialsTsinghua UniversityBeijing 100084China

Antibiotics are a widely used and effective treatment for bacterial infections.However,bacteria can gradually evolve during infection,leading to developing resistance to antibiotics,which renders previously effective treatments ineffective.Finding a useful and convenient manner to treat bacterial infections is a great challenge.Here,we report a flexible hydrogen-bond-bridged phosphorene film with photodynamic antibacterial properties and excellent mechanical properties,fabricated from electrochemical exfoliation of black phosphorus(BP).When illuminated under 700 nm light,the hydrogen bond-bridged phosphorene flexible film is capable of converting ground-state triplet oxygen(O_(2))into excited-state singlet oxygen(^(1)O_(2)),destroying the structure of the membrane of Staphylococcus aureus,and eventually leading to bacterial death,via breaking the C=C of unsaturated fatty acids within the bacterial cell membrane after the reaction between^(1)O_(2)and unsaturated fatty acids,thus realizing a highly efficient antibacterial approach,which is supported by gas chromatography-mass spectrometry(GC-MS)technique.This work establishes an effective phototherapy platform for treating bacterial traumatic infections.

关键词： hydrogen bond-bridged phosphorene flexible film photodynamic Staphylococcus aureus

Data Component:An Innovative Framework for Information Value Metrics in the Digital Economy

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China Communications 2024年第5期21卷 17-35页

作者： Tao Xiaoming Wang Yu Peng Jieyang Zhao Yuelin Wang Yue Wang Youzheng Hu Chengsheng Lu Zhipeng Department of Electronic engineering Tsinghua UniversityBeijing 100084China beijing National research center for Information Science and Technology Beijing 100084China China Electronics Corporation Beijing 100084China

The increasing dependence on data highlights the need for a detailed understanding of its behavior,encompassing the challenges involved in processing and evaluating it.However,current research lacks a comprehensive structure for measuring the worth of data elements,hindering effective navigation of the changing digital environment.This paper aims to fill this research gap by introducing the innovative concept of“data components.”It proposes a graphtheoretic representation model that presents a clear mathematical definition and demonstrates the superiority of data components over traditional processing methods.Additionally,the paper introduces an information measurement model that provides a way to calculate the information entropy of data components and establish their increased informational value.The paper also assesses the value of information,suggesting a pricing mechanism based on its significance.In conclusion,this paper establishes a robust framework for understanding and quantifying the value of implicit information in data,laying the groundwork for future research and practical applications.

关键词： data component data element data governance data science information theory

Enhanced antibacterial activity,corrosion resistance and endothelialization potential of Ti-5Cu alloy by oxygen and nitrogen plasma-based surface modification

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Journal of Materials Science & Technology 2024年第1期168卷 250-264页

作者： Xiaotong Zhao Jiali Hu Jingjun Nie Dafu Chen Gaowu Qin Erlin Zhang Key Lab.for Anisotropy and Texture of Materials Education Ministry of ChinaSchool of Materials Science and EngineeringNortheastern UniversityShenyang 110819China research center for Metallic Wires Northeastern UniversityShenyang 110819China Laboratory of Bone Tissue engineering Beijing Laboratory of Biomedical MaterialsNational Center for OrthopaedicsBeijing Research Institute of Traumatology and OrthopaedicsBeijing Jishuitan HospitalBeijing 100035China

Antibacterial Ti-5Cu alloy is a promising substitute material for Ti-made cardiovascular implants,so its surface engineering is crucial to expediting clinical implementation.Given the antibacterial and cardiovas-cular biological benefits of Cu^(2+)and titanium-nitride-oxide(TiN x O y)coatings,a Cu_(2)O/CuO-TiN x O y coating with upregulated Cu^(2+)release was successfully deposited on Ti-5Cu alloy for the first time using oxygen and nitrogen plasma-based surface modification.The superhydrophilic and nanostructured Cu_(2)O/CuO-TiN x O y coating had a dense structure and was well bonded to the substrate,resulting in enhanced cor-rosion resistance,while CuO/Cu_(2)O in the coating released Cu^(2+)faster than Ti_(2)Cu phase in the matrix.More gratifying,the coating demonstrated perfect antibacterial properties(R>99.9%against S.aureus),owing primarily to direct contact sterilization of Cu_(2)O/CuO.The most encouraging phenomenon was that the coating dramatically accelerated HUVEC adhesion(1.4 times),proliferation(RGR:106%-116%),and particularly migration(RMR:158%-247%)compared with the control Ti.The coating extract also signifi-cantly stimulated in vitro angiogenesis capacity.The rapid endothelialization for Cu_(2)O/CuO-TiN x O y coating was attributed to the surface nanostructure and Cu^(2+)/NO_(2)−release,which upregulated the angiogenesis-related gene expression of HIF-1α,VEGF,and eNOS to increase VEGF secretion and NO production.All of the findings indicated that the Cu_(2)O/CuO-TiN x O y coating could enhance the corrosion resistance,an-tibacterial properties,and endothelialization potential of Ti-Cu alloy,displaying great clinical potential in cardiovascular applications.

关键词： Titanium-copper alloy Titanium-nitride-oxide(TiNxOy) Cu^(2+)release Antibacterial property Cell compatibility

A New Heat Transfer Model for Multi-Gradient Drilling with Hollow Sphere Injection

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Fluid Dynamics & Materials Processing 2024年第3期20卷 537-546页

作者： Jiangshuai Wang Chuchu Cai Pan Fu Jun Li Hongwei Yang Song Deng School of Petroleum and Natural Gas engineering Changzhou UniversityChangzhouChina CNPC research Institute of engineering Technology Co. Ltd.BeijingChina National engineering research center for Oil&Gas Drilling and Completion Technology BeijingChina College of Petroleum engineering China University of Petroleum(Beijing)BeijingChina College of Petroleum Karamay CampusChina University of Petroleum(Beijing)BeijingChina

Multi-gradient drilling is a new offshore drilling method.The accurate calculation of the related wellbore temperature is of great significance for the prediction of the gas hydrate formation area and the precise control of the wellbore pressure.In this study,a new heat transfer model is proposed by which the variable mass flow is properly taken into account.Using this model,the effects of the main factors influencing the wellbore temperature are analyzed.The results indicate that at the position where the separation injection device is installed,the temperature increase of the fluid in the drill pipe is mitigated due to the inflow/outflow of hollow spheres,and the temperature drop of the fluid in the annulus also decreases.In addition,a lower separation efficiency of the device,a shallower installation depth and a smaller circulating displacement tend to increase the temperature near the bottom of the annulus,thereby helping to reduce the hydrate generation area and playing a positive role in the prevention and control of hydrates in deepwater drilling.

关键词： Multi-gradient drilling wellbore temperature hydrate separate injection device variable mass

Control of GaN inverted pyramids growth on c-plane patterned sapphire substrates

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Journal of Semiconductors 2024年第6期45卷 92-96页

作者： Luming Yu Xun Wang Zhibiao Hao Yi Luo Changzheng Sun Bing Xiong Yanjun Han Jian Wang Hongtao Li Lin Gan Lai Wang beijing National research center for Information Science and Technology Department of Electronic EngineeringTsinghua UniversityBei-jing 100084China center for Flexible Electronics Technology Tsinghua UniversityBeijing 100084China

Growth of gallium nitride(GaN)inverted pyramids on c-plane sapphire substrates is benefit for fabricating novel devices as it forms the semipolar facets.In this work,GaN inverted pyramids are directly grown on c-plane patterned sapphire substrates(PSS)by metal organic vapor phase epitaxy(MOVPE).The influences of growth conditions on the surface morphol-ogy are experimentally studied and explained by Wulff constructions.The competition of growth rate among{0001},{1011},and{1122}facets results in the various surface morphologies of GaN.A higher growth temperature of 985 ℃ and a lowerⅤ/Ⅲratio of 25 can expand the area of{}facets in GaN inverted pyramids.On the other hand,GaN inverted pyramids with almost pure{}facets are obtained by using a lower growth temperature of 930℃,a higherⅤ/Ⅲratio of 100,and PSS with pattern arrangement perpendicular to the substrate primary flat.

关键词： inverted pyramids GaN MOVPE crystal growth competition model