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Effect of neutral polymeric bonding agent on tensile mechanical properties and damage evolution of NEPE propellant

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defence Technology（防务技术） 2024年第2期32卷 357-367页

作者： m.Wubuliaisan Yanqing Wu Xiao hou Kun Yang Hongzheng duan Xinmei Yin State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China The Fourth Institute of China Aerospace Science and Technology Corporation Xi'an710025PR China School of Aerospace Engineering Beijing Institute of TechnologyBeijing100081PR China Science and Technology on Aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechnologyHubei441003PR China

Introducing Neutral Polymeric bonding agents(NPBA) into the Nitrate Ester Plasticized Polyether(NEPE)propellant could improve the adhesion between filler/matrix interface, thereby contributing to the development of new generations of the NEPE propellant with better mechanical properties. Therefore,understanding the effects of NPBA on the deformation and damage evolution of the NEPE propellant is fundamental to material design and applications. This paper studies the uniaxial tensile and stress relaxation responses of the NEPE propellant with different amounts of NPBA. The damage evolution in terms of interface debonding is further investigated using a cohesive-zone model(CZm). Experimental results show that the initial modulus and strength of the NEPE propellant increase with the increasing amount of NPBA while the elongation decreases. meanwhile, the relaxation rate slows down and a higher long-term equilibrium modulus is reached. Experimental and numerical analyses indicate that interface debonding and crack propagation along filler-matrix interface are the dominant damage mechanism for the samples with a low amount of NPBA, while damage localization and crack advancement through the matrix are predominant for the ones with a high amount of NPBA. Finally, crosslinking density tests and simulation results also show that the effect of the bonding agent is interfacial rather than due to the overall crosslinking density change of the binder.

关键词： Solid propellant Bonding agent mechanical properties damage evolution Cohesive-zone model Interface debonding

In vitro investigations on the effects of graphene and graphene oxide on polycaprolactone bone tissue engineering scaffolds

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Bio-design and manufacturing 2024年第5期7卷 651-669页

作者： Yanhao hou Weiguang Wang Paulo Bartolo School of Engineering Faculty of Science and EngineeringThe University of ManchesterManchesterUK Singapore Centre for 3d Printing School of Mechanical and Aerospace EngineeringNanyang Technological UniversitySingaporeSingapore

Polycaprolactone(PCL)scaffolds that are produced through additive manufacturing are one of the most researched bone tissue engineering structures in the *** to the intrinsic limitations of PCL,carbon nanomaterials are often investigated to reinforce the PCL *** several studies that have been conducted on carbon nanomaterials,such as graphene(G)and graphene oxide(GO),certain challenges remain in terms of the precise design of the biological and nonbiological properties of the *** paper addresses this limitation by investigating both the nonbiological(element composition,surface,degradation,and thermal and mechanical properties)and biological characteristics of carbon nanomaterial-reinforced PCL scaffolds for bone tissue engineering *** showed that the incorporation of G and GO increased surface properties(reduced modulus and wettability),material crystallinity,crystallization temperature,and degradation ***,the variations in compressive modulus,strength,surface hardness,and cell metabolic activity strongly depended on the type of ***,a series of phenomenological models were developed based on experimental results to describe the variations of scaffold’s weight,fiber diameter,porosity,and mechanical properties as functions of degradation time and carbon nanomaterial *** results presented in this paper enable the design of three-dimensional(3d)bone scaffolds with tuned properties by adjusting the type and concentration of different functional fillers.

关键词： Additive manufacturing Bone tissue engineering Carbon nanomaterial Graphene Graphene oxide Scaffold

Tailored energy absorption for a novel auxetic honeycomb structure under large deformation

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Science China(Physics,mechanics & Astronomy) 2024年第5期67卷 63-80页

作者： Xiuhui hou Bin Wang Zichen deng School of mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710129China mIIT Key Laboratory of dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi'an 710072China School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

In comparison to conventional hexagonal honeycomb structures,auxetic metamaterials with re-entrant configurations have exhibited superior mechanical properties in terms of energy *** further enhance the energy absorption capacity of these materials,a novel re-entrant honeycomb configuration,named novel auxetic re-entrant honeycomb(NARH),is developed by incorporating“”-shaped cell walls into the conventional auxetic re-entrant honeycomb(ARH).Two analytical models for the plateau stress are formulated to consider the plastic deformation of NARH during quasi-static compression and the dynamic impact using the linear momentum ***-static compression tests on 3d printed NARH honeycomb specimens and finite element simulations are performed to verify the effectiveness of the theoretical *** exhibits higher plateau stresses compared with ARH during compression,which can be attributed to the presence of more plastic hinges formed in *** hinges,the embedded parts with inclined cell walls,not only improve stability by forming stable triangles during compression but also enhance the energy absorption capacity.A parametric study is conducted to analyze the effect of impact velocity,thickness,and incline angle of cell walls on *** simulations demonstrate higher sensitivity of the mechanical properties to impact velocity and cell wall *** ribs to the“”-shaped cell walls in NARH further reduces the initial peak force during dynamic crushing while maintaining high energy *** research provides valuable guidelines for the design of energy absorption metamaterials.

关键词： absorption walls shaped

multidimensional coupled structure-activity relationship models for replacement of SF_(6)

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High Voltage 2024年第2期9卷 484-494页

作者： mi Zhang Hua hou Baoshan Wang College of Chemistry and molecular Sciences Wuhan UniversityWuhanChina

Computational screening of single gases to replace SF_(6)for electrical insulation has been challenged by the difficulty in combining various mutually exclusive properties especially for dielectric performance with liquefaction and environmental *** reveal the inherent correlations between dielectric strength(Er),boiling point(Tb),and global warming potential(GWP)of dielectric materials,a coupled structure-activity relationship(CSAR)model has been proposed for the first *** means of the generic descriptors,as deduced from the electrostatic potentials,and the specific descriptors,as introduced from the respective microscopic mechanisms,the complex interdependence between Er,Tb,and GWP of the insulation gases is quantitatively characterised by the 3-d coupling *** coupling mechanism for the right balance of properties is uncovered in terms of the first-principle *** CSAR model outperforms the previous SAR models in predicting Er,Tb,and GWP simultaneously in a self-consistent *** importantly,the concept of CSAR could be extended readily to any multidimensional macroscopic *** replacement compounds have been identified tentatively to be the promising candidates to replace SF_(6)using the CSAR model.

关键词： properties. dielectric insulation

Influence of Component Size on the Corrosion Behavior of Ti6Al4V Alloy Fabricated by Electron Beam Powder Bed Fusion

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Acta metallurgica Sinica(English Letters) 2024年第1期37卷 159-168页

作者： Hongyu Zheng Xin Gai Yun Bai Wentao hou Shujun Li Yulin Hao R.d.K.misra Rui Yang Institute of metal Research Chinese Academy of SciencesShenyang110016China School of materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Nuclear Power Institute of China Chengdu610213China department of metallurgical Materialsand Biomedical EngineeringThe University of Texas at El Paso500WUniversity AvenueEl PasoTX79968USA

The electrochemical behavior of Ti-6Al-4V with 1 mm and 16 mm thickness prepared by electron beam powder bed fusion(EB-PBF)was investigated in phosphate buffered *** results showed that EB-PBF Ti-6Al-4V with a larger component size was more resistant to corrosion compared to the smaller component,because of less acicularαʹphase content and moreβphase *** a non-equilibrium phase in the“high-energy state”,αʹphase has a greater susceptibility to corrode and reduces the corrosion resistance of the material,whileβphase improves corrosion resistance of titanium *** results show that the phase composition has a more significant effect on the corrosion performance than the grain size.

关键词： Electron beam powder bed fusion Ti6Al4V alloy Corrosion resistance Component size Polarisation

Palladium(Ⅱ)-Catalyzed markovnikov Hydroalkynylation of Unactivated Terminal Alkenes

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Chinese Journal of Chemistry 2024年第1期42卷 29-34页

作者： Chuanqi hou Pinhong Chen Guosheng Liu Sstate Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical SynthesisCenter for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200032China Chang-Kung Chuang Institute East China Normal UniversityShanghai 200062China

Alkynes are versatile synthons in organic synthesis,as well as important structural moieties in bioactive ***,transition metal-catalyzed hydroalkynylation of alkenes has been developed with reactive alkenes and alkenes bearing directing ***,the regioselective hydroalkynylation of simple alkenes is still ***,we have developed a palladium-catalyzed markovnikov hydroalkynylation of unactivated terminal alkenes,which provides an efficient approach for the synthesis of branched alkynyl compounds under mild *** reaction features excellent functional group tolerance,good reaction yields and excellent ***,the asymmetric hydroalkynylation reaction has also been achieved with moderate enantioselectivity by introducing a sterically bulky chiral Pyox ligand.

关键词： Palladium catalysis Alkynylpalladation Unactivated terminal alkenes markovnikov hydroalkynylation

Investigation of high rate mechanical flow followed by ignition for high-energy propellant under dynamic extrusion loading

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defence Technology（防务技术） 2024年第2期32卷 336-347页

作者： Liying dong Yanqing Wu Kun Yang Xiao hou State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China

Investigating the ignition response of nitrate ester plasticized polyether(NEPE) propellant under dynamic extrusion loading is of great significant at least for two cases. Firstly, it helps to understand the mechanism and conditions of unwanted ignition inside charged propellant under accident ***, evaluates the risk of a shell crevice in a solid rocket motor(SRm) under a falling or overturning scene. In the present study, an innovative visual crevice extrusion experiment is designed using a dropweight apparatus. The dynamic responses of NEPE propellant during extrusion loading, including compaction and compression, rapid shear flow into the crevice, stress concentration, and ignition reaction, have been firstly observed using a high-performance high-speed camera. The ignition reaction is observed in the triangular region of the NEPE propellant sample above the crevice when the drop weight velocity was 1.90 m/s. Based on the user material subroutine interface UmAT provided by finite element software LS-dYNA, a viscoelastic-plastic model and dual ignition criterion related to plastic shear dissipation are developed and applied to the local ignition response analysis under crevice extrusion conditions. The stress concentration occurs in the crevice location of the propellant sample, the shear stress is relatively large, the effective plastic work is relatively large, and the ignition reaction is easy to occur. When the sample thickness decreases from 5 mm to 2.5 mm, the shear stress increases from 22.3 mPa to 28.6 mPa, the critical value of effective plastic work required for ignition is shortened from 1280 μs to 730 μs, and the triangular area is easily triggering an ignition reaction. The propellant sample with a small thickness is more likely to stress concentration, resulting in large shear stress and effective work, triggering an ignition reaction.

关键词： NEPE propellant Crevice extrusion Shear flow Sample thickness Ignition reaction

direct Conversion of methane to Propylene

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Research 2024年第2期2023卷 463-472页

作者： Yunpeng hou Yuxiang Lan Chao Qian Shaodong Zhou College of Chemical and Biological Engineering Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture TechnologyZhejiang University310027 HangzhouP.R.China Zhejiang Provincial Innovation Center of Advanced Chemicals Technology Institute of Zhejiang University-Quzhou324000 QuzhouP.R.China

Nonoxidative coupling of methane exhibits promising prospect in that it affords value-added hydrocarbons and hydrogen with high atom ***,challenge remains in direct,selective conversion of methane to more valuable hydrocarbons like *** current work presents a catalyst with well-dispersed Ta atoms anchored by graphitic C_(3)N_(4)-supported *** a catalyst is able to convert methane selectively to ethylene and propylene at a relatively low temperature(350℃).The conception of the active center and construction of the catalyst have been described,and the origins of the catalytic performance are discussed.

关键词： methane catalyst hydrocarbons

The variation of dOm during long distance water transport by the China South to North Water diversion Scheme and impact on drinking water treatment

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 85-100页

作者： Hankun Yang Yujuan Li Hongyu Liu Nigel J.d.Graham Xue Wu Jiawei hou mengjie Liu Wenyu Wang Wenzheng Yu State Key Laboratory of Environmental Aquatic Chemistry Key Laboratory of Drinking Water Science and TechnologyResearch Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing100085China School of Environment and municipal Engineering Qingdao Technological UniversityQingdao266033China Colleges of Forestry Northeast Forestry UniversityHarbin150006China department of Civil and Environmental Engineering Imperial College LondonSouth Kensington CampusLondonSW7 2AZUK School of Chemistry and Chemical Engineering Beijing Institute of TechnologyBeijing100081China State Key Laboratory of Separation membrane Processes School of Environment Science and EngineeringTiangong UniversityTianjin300387China

In this study,samples were taken from three locations,upstream to downstream,along the central route project of the China South to North Water diversion(SNWd)scheme in summer and *** were used to reveal the variations of dissolved organic matter(dOm)during the water transfer process,and the effects of these variations on drinking water treatment and disinfection by-products formation potential(dBPs-FP).The results showed that polysaccharides accumulate in summer and reduce in winter with flow distance,which has an important effect on the overall properties of dOm,as well as on the performance of coagulation,ultrafiltration,and the formation of *** substances,and their hydrophilic content,also increased in summer and decreased in winter with flow *** contrast,the concentration of small organic substances(mW≤1000 da)increased in both summer and winter with flow distance,which affected both nanofiltration(NF)membrane fouling and *** results provide a useful case study of spatial and temporal changes in raw water dOm during long distance water transfer and their impact on the treatment and quality of drinking water from the SNWd.

关键词： Long-distance water transfer The China South to North Water diversion Scheme Coagulation membrane filtration disinfection by-products