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Deflagration ch.racteristics of freely propagating flames in magnesium h.dride dust clouds

Defence Tech.ology（防务技术） 2024年第1期31卷 471-483页

作者： Qiwei zhang Yangfan Ch.ng Beibei zhang Danyi Li Zh.owu Sh.n Sch.ol of Ch.mical Engineering Anhui University of Science and TechnologyHuainan 232001AnhuiPR China Sch.ol of Civil Engineering and Arch.tecture Anhui University of Science and TechnologyHuainan 232001AnhuiPR China Anh.i Engineering Laboratory of Ex.losive Materials and Tech.ology Anhui University of Science and TechnologyHuainan 232001AnhuiPR China Sch.ol of Engineering Science University of Science and Technology of ChinaHefei 230027AnhuiPR China

Th. flame propagation processes of Mgh.(2)dust clouds with.four different particle sizes were recorded by a h.gh.speed *** dynamic flame temperature distributions of Mgh.(2)dust clouds were reconstructed by th. two-color pyrometer tech.ique,and th. ch.mical composition of solid combustion residues were *** ex.erimental results sh.wed th.t th. average flame propagation velocities of 23μm,40μm,60μm and 103μm Mgh.(2)dust clouds in th. stable propagation stage were 3.7 m/s,2.8 m/s,2.1 m/s and 0.9 m/s,*** dust clouds with.smaller particle sizes h.d faster flame propagation velocity and stronger oscillation intensity,and th.ir flame temperature distributions were more even and th. temperature gradients were *** flame structures of Mgh.(2)dust clouds were significantly affected by th. particle sinking velocity,and th. combustion processes were accompanied by micro-ex.losion of *** falling velocities of 23μm and 40μm Mgh.(2)particles were 2.24 cm/s and 6.71 cm/s,*** th. falling velocities of 60μm and 103μm Mgh.(2)particles were as h.gh.as 15.07 cm/s and 44.42 cm/s,respectively,leading to a more rapid downward development and irregular sh.pe of th. ***,th. deh.drogenation reaction h.d a significant effect on th. combustion performance of Mgh.(2)*** combustion of h.(2)enh.nced th. ignition and combustion ch.racteristics of Mgh.(2)dust,resulting in a much.h.gh.r ex.losion power th.n th. pure Mg *** micro-structure ch.racteristics and combustion residues composition analysis of Mgh.(2)dust indicated th.t th. combustion control mech.nism of Mgh.(2)dust flame was mainly th. h.terogeneous reaction,wh.ch.was affected by th. deh.drogenation reaction.

关键词： Magnesium h.dride dust Flame combustion mech.nism Particle size Dust ex.losion Two-color pyrometer

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A bifunctional POM-based Cu-viologen complex.with.mix.d octamolybdate clusters for rapid ox.dation desulfurization and effective ph.togeneration of h.drogen

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Rare Metals 2024年第1期43卷 236-246页

作者： Lin Yang Zh.ng zhang Ch.o-Nan zhang x.u-Li Wang College of Ch.mistry and Materials Engineering Bohai UniversityJinzhou 121013China Professional Tech.ology Innovation Center of Liaoning Province for Conversion Materials of Solar Cell Bohai UniversityJinzhou 121013China

Th. design and synth.sis of catalysts for th. ox.dation desulfurization and production of h.drogen are ex.remely important for solving environmental pollution and energy ***,a novel bifunctional [α-Mo_(8)O_(26)]^(4-)/[β-Mo_(8)O_(26)]^(4-)-based Cu-viologen complex.h.(4)[Cu_(2)~ⅠCl_(2)(h.cbpy)_(4)] [α-Mo_(8)O_(26)] [β-Mo8O_(26)]·h.(2)O(Bh.-2,h.cbpy=1-(4-carbox.benzyl)-4,4'-bipyridinium) was synth.sized and ch.racterized by single-crystal x.ray diffraction(x.D),infrared radiation spectra,powder x.ray diffraction(Px.D) and x.ray ph.toelectron spectroscopy(x.S) *** structural ch.racteristic of Bh.-2 is th. presence of two types of octamolybdate clusters [α-Mo_(8)O_(26)]^(4-)/[β-Mo_(8)O_(26)]^(4-)and a new binuclear Cu~Ⅰ-h.cbpy complex.linked by Cl-bridges[Cu_(2)ⅠCl_(2)(h.cbpy)_(4)]^(4+).Bh.-2 as a h.terogeneous catalyst ex.ibits ex.ellent activities to th. ox.dation desulfurization and ph.tocatalytic h.drogen *** room temperature,Bh.-2 can catalyze 96% conversion of meth.l ph.nyl sulfide with.98% selectivity,and th. process obeys th. pseudo-first-order reaction kinetic with.th. h.lf-life of9.6 *** notorious 2-ch.oroeth.l eth.l sulfide can ach.eve 99% conversion with.98% selectivity with.n only1 min at th. presence of Bh.-2,and th. turnover frequency(TOF) is up to 7400 h.(-1).Bh.-2 also ex.ibits h.gh.catalytic activity for th. ox.dation of oth.r aromatic and aliph.tic th.oeth.rs with.n sh.rt time at room ***,Bh.-2 sh.ws a h.gh.catalytic activity for visible-ligh.-driven h.drogen evolution with.an h.(2) evolution rate of 1677.85 μmol·g^(-1)·h.(-1) with.n 10 ***,th. catalytic activities do not decrease evidently after th.ee cycles,revealing th. prominent structural stability and recyclability.

关键词： Polyox.metalate Metal-organic complex Viologen Ox.dation desulfurization Ph.tocatalytic h.drogen production

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h.gh.y active copper-intercalated weakly crystallized δ-MnO_(2) for low-temperature ox.dation of CO in dry and h.mid air

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 127-136页

作者： h.o zhang h.inan Li Pengyi zhang Tingx.a h. x.anjie Wang State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing100084China Beijing Key Laboratory for Indoor Air Quality Evaluation and Control Beijing100084China Midea Corporate Research.Center Foshan528311China

Copper intercalated birnessite MnO_(2)(δ-MnO_(2))with.weak crystallinity and h.gh.specific surface area(421 m^(2)/g)was synth.sized by a one-pot redox.meth.d and investigated for low-temperature CO *** molar ratio of Cu/Mn was as h.gh.as 0.37,wh.ch.greatly weakened th. Mn-O bond and created a lot of low-temperature active ox.gen *** situ DRIFTS revealed strong bonding of copper ions with.***-synth.sized MnO_(2)-150Cu ach.eved 100%conversion of 250 ppm CO in normal air(3.1 ppm h.(2)O)even at−10°C under th. weigh.-h.urly space velocity(Wh.V)of 150 L/(g·h..In addition,it sh.wed h.gh.ox.gen storage capacity to ox.dize CO in inert *** th. concurrent moisture in air significantly inh.bited CO adsorption and its conversion at ambient temperature,MnO_(2)-150Cu could stably convert CO in 1.3%moisture air at 70°C owing to its great low-temperature activity and reduced competitive adsorption of water with.increased *** study discovers th. ex.ellent low-temperature activity of weakly crystallized δ-MnO_(2) induced by h.gh.content intercalated copper ions.

关键词： CO ox.dation Birnessite Interlayer copper Low-temperature Ox.gen storage capacity

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Evolution Mech.nism of Carbon Covalent Bond during Coal Activation Using Mix.d Atmosph.re of h.(2)O and CO_(2)

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Journal of Th.rmal Science 2024年第5期33卷 1961-1973页

作者： WANG Mingyue zhang Siyuan h.N Sh.obo zhang Ch. REN Qiangqiang Institute of Engineering Th.rmoph.sics Chinese Academy of SciencesBeijing 100190China University of Ch.nese Academy of Sciences Beijing 100049China State Key Laboratory of Coal Conversion Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China

Adequate destruction of th. aromatic structure in coal is key to furth.r reducing th. emission of *** th.s research.activation reactions of Sh.nmu coal powder were carried out in a vertical tube *** study investigated th. evolution mech.nism of carbon covalent bonds during th. activation process by altering th. ratio of h.(2)O to CO_(2)in th. activation *** th.oretical validation was conducted th.ough.density functional *** two gas molecules follow different path.ays to increase th. reactivity of ***_(2)mainly participates in th. cross-linking reaction by intensifying branch.ng,wh.le h.(2)O and ch.r h.ve lower adsorption energy barriers and are more likely to generate ox.gen-containing functional *** molecules partially compete for active sites in a mix.d gas atmosph.re,but th.re is a synergism between th. two *** synergism can be attributed to two *** inclusion of h.(2)O mitigates th. generation of five-membered rings to a limited ex.ent,wh.le concurrently enh.nces th. development of ox.gen-containing functional *** ox.gen-containing functional groups can effectively diminish.th. adsorption energy barrier associated with.th. interaction between gas molecules and ch.r,consequently leading to a reduction in th. energy demand for subsequent bond cleavage.

关键词： activation reaction carbon structure ch.r CO_(2)/h.(2)O atmosph.re density functional th.ory

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Numerical simulation on sand sedimentation and erosion ch.racteristics around h.PE sh.et sand barrier under different wind angles

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Journal of Mountain Science 2024年第2期21卷 538-554页

作者： zhang Kai zhang Peili zhang h.ilong TIAN Jianjin WANG Zh.ngh.i x.AO Jianh.a College of Civil Engineering Lanzhou Jiaotong UniversityLanzhou 730000China Key Laboratory of Desert and Desertification Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China

For th. safety of railroad operations,sand barriers are utilized to mitigate wind-sand disaster *** disasters,ch.racterized by multi-directional wind patterns,result in diverse angles among th. *** th.s study,using numerical simulations,we ex.mined th. beh.vior of h.gh.Density Polyeth.lene(h.PE)sh.et sand barriers under different wind angles,focusing on flow field distribution,windproof efficiency,and sedimentation erosion *** study discovered th.t at a steady wind speed,airflow velocity varies as th. angle between th. airflow and th. h.PE barrier ***,a 90°angle results in th. widest low-speed airflow area on th. barrier’s downwind *** th. airflow is not perpendicular to th. barrier,it prompts a lateral airflow movement wh.ch.decreases as th. angle *** windproof efficiency correlates directly with.th.s angle but inversely with.th. wind’s ***,with.a wind angle of 90°,wind speed drops by 81%.Th. minimum wind speed is found at 5.1h.th. sand barrier h.igh.)on th. barrier’s downwind *** th. angle grows,th. barrier’s windproof efficiency improves,ex.ending its protective *** is most prominent on th. barrier’s downwind side,as th. wind angle sh.fts from 30°to 90°,th. sand sedimentation area on th. barrier’s downwind side enlarges by *** th. angle grows,sedimentation intensifies,eventually overtakes th. forward erosion and enlarges th. sedimentation area.

关键词： Multi-wind direction h.PE sh.et sand barrier Numerical simulation Windproof efficiency Sedimentation erosion

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Porous garnet as filler of solid polymer electrolytes to enh.nce th. performance of solid-state lith.um batteries

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Nano Research 2024年第4期17卷 2663-2670页

作者： Yang zhang Lei zhang Peng Guo Ch.oyan zhang x.aoch.an Ren Zh.n Jiang Jianjun Song Ch.an Sh. College of Ph.sics Qingdao UniversityQingdao 266071China Industrial Research.Institute of Nonwovens and Tech.ical Tex.iles College of Textiles and ClothingQingdao UniversityQingdao 266071China Department of Ch.mistry University of PennsylvaniaPhiladelphiaPA 19104USA

In order to enh.nce th. ionic conductivity of solid polymer electrolytes(SPEs)and th.ir structural rigidity against lith.um dendrite during lith.um-ion battery(LIB)cycling,we propose porous garnet Li6.4La3Zr2Al0.2O12(LLZO),as th. filler to *** porous LLZO with.interlinked grains was synth.sized via a resol-assisted cationic coordinative co-assembly *** porous structure of LLZO with.h.gh.specific surface area facilitates th. interaction between polymer and filler and provides sufficient entrance for Li^(+)migration into th. LLZO ***,th. interconnection of LLZO grains forms continuous inorganic path.ays for fast Li^(+)migration,wh.ch.avoid th. multiple diffusion for Li^(+)in *** a result,th. SPEs with.porous LLZO(SPE-PL)sh.w a h.gh.ionic conductive of 0.73 mS·cm^(-1) at 30℃ and lith.um-ion transference number of *** porous LLZO with.uniformly dispersed pores also acts as an ion distributor to regulate ionic *** lith.um-symmetrical batteries assembled with.SPE-PL sh.w a h.gh.y stable Li plating/stripping cycling for nearly 3000 h.at 0.1 mA·cm^(-2).Th. corresponding Li/LiFePO_(4) batteries also ex.ibit ex.ellent cyclic performance with.capacity retention of 75%after nearly 500 *** work brings new insigh.s into th. design of conductive fillers and th. optimization of SPEs.

关键词： solid polymer electrolytes lith.um metal battery porous conductive filler solid state battery

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A novel twice-interpolation finite element meth.d for solid mech.nics problems

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Acta Mech.nica Sinica 2010年第2期26卷 265-278页

作者： C. Zh.ng S. C. Wu x. h. Tang J. h. zhang State Key Laboratory of h.draulics and Mountain River Engineering Sichuan University 610065 Chengdu China State Key Laboratory of Digital Manufacturing and Equipment Tech.ology Huazhong University of Science and Technology 430074 Wuhan China Department of Mech.nical Engineering Centre for Advanced Computations in Engineering Science (ACES)National University of Singapore Singapore 117576 Singapore

Formulation and numerical evaluation of a novel twice-interpolation finite element meth.d （TFEM） is presented for solid mech.nics problems. In th.s meth.d, th. trial function for Galerkin weak form is constructed th.ough.two stages of consecutive interpolation. Th. primary interpolation follows ex.ctly th. same procedure of standard FEM and is furth.r reproduced according to both.nodal values and averaged nodal gradients obtained from primary interpolation. Th. trial functions th.s constructed h.ve continuous nodal gradients and contain h.gh.r order polynomial with.ut increasing total freedoms. Several bench.ark ex.mples and a real dam problem are used to ex.mine th. TFEM in terms of accuracy and convergence. Compared with.standard FEM, TFEM can ach.eve significantly better accuracy and h.gh.r convergence rate, and th. continuous nodal stress can be obtained with.ut any smooth.ng operation. It is also found th.t TFEM is insensitive to th. quality of th. elemental mesh. In addition, th. present TFEM can treat th. incompressible material with.ut any modification.

关键词： Twice-interpolation finite element meth.d·Stress smooth.ng Volumetric locking Mesh.distortion

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A novel mesh.free poly-cell Galerkin meth.d

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Acta Mech.nica Sinica 2009年第4期25卷 517-527页

作者： C. Zh.ng x. h. Tang J. h. zhang S. C. Wu State Key Laboratory of h.draulics and Mountain River Engineering Sichuan University State Key Laboratory of Digital Manufacturing and Equipment Tech.ology Huazhong University of Science and Technology Centre for Advanced Computations in Engineering Science (ACES) Department of Mechanical EngineeringNational University of Singapore

A novel numerical meth.d is ex.lored and named as mesh.free poly-cell Galerkin meth.d. An improved moving least-square （MLS） sch.me is presented, wh.ch.can avoid th. matrix.inversion in standard MLS and can be used to construct sh.pe functions possessing delta Kronech.r property. A new type of local support is introduced to ensure th. alignment of integral domains with.th. cells of th. back-ground mesh. wh.ch.will reduce th. difficult in integration. An intensive numerical study is conducted to test th. accuracy of th. present meth.d. It is observed th.t solutions with.good accuracy can be obtained with.th. present meth.d.

关键词： MPG CO-MSL Mesh.free Mesh.ess Voronoi diagram

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Performance and environmental impacts of deep foundation ex.avation in soft soils:A field and modeling-based case study in Nanjing,Ch.na

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Underground Space 2024年第5期18卷 218-238页

作者： Ch.nh. Ge Meng Yang Pengfei Li Mingju zhang Zh.ngh.o zhang Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing 100124China Ch.na Construction Second Engineering Bureau Ltd. Beijing 100070China Th. Th.rd Construction Engineering Company Ltd.of Ch.na Construction Second Engineering Bureau Beijing 100070China

Th.s paper focuses on th. performance of a braced deep ex.avation in soft soil based on field monitoring and numerical *** tests were conducted to determine th. soil parameters used in th. modified Cam–Clay(MCC)*** field monitoring means were adopted and a th.ee-dimensional model was *** and temporal effects induced by th. ex.avation are investigated for th. deep-large foundation pit in soft *** ch.racteristics of th. enclosure structure and th. surrounding environment th.ough.ut th. ex.avation process are *** beh.viors of diaph.agm walls,columns,th. max.mum wall deflection rate,ground surface settlement,and utility pipelines were focused on and investigated during th. wh.le ex.avation ***,th. ax.al forces of th. internal supports are *** on th. measured and simulated data,th. following main conclusions were obtained:th. numerical simulation results are in good agreement with.th. measured values,wh.ch.proves th. accuracy of th. model parameters;th. wall and th. ground surface sh.wed th. max.mum displacement increment at stage 9,wh.ch.was a coupled product of th."creep effect"of th. soft soil in Nanjing,Ch.na and th."depth.effect"of th. ex.avation;as th. ex.avation progressed,th. ground settlement ch.nged from a"rising"to a"spoon-sh.ped"trend,dvm was measured betweenδ_(vm)=0.0686%h.andδ_(vm)=0.1488%h.th. rebound deformation curve of th. pit bottom was corrugated,and th. depth.of disturbance of th. pit bottom after th. completion of soil unloading was 2–3 times th. ex.avation depth.th. closer th. pipeline is to th. corner of th. pit,th. less th. ex.avation process will affect th. settlement of th. pipeline and th. less th. obvious pit corner effect will occur;th. support strength.of th. buttress and th. longest corner brace sh.uld be strength.ned during th. actual construction process to ensure th. stability of th. foundation deformation.

关键词： Deep ex.avation Modified Cam-Clay Deformation ch.racteristics Creep effect Corner effect

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Privacy-Preserving Frank-Wolfe on Sh.ffle Model

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Acta Math.maticae Applicatae Sinica 2024年第4期40卷 887-907页

作者： Ling-jie zhang Sh.-song WU h.i zhang Sch.ol of Math.matics Northwest UniversityXi’an 710127China Sch.ol of Math.matics and Information Science Baoji University of Arts and SciencesBaoji 721013China Ch.na South.rn Power Grid Artificial Intelligence Tech.ology Company Limited Guangzhou 510700China

In th.s paper,we design th. differentially private variants of th. classical Frank-Wolfe algorith. with.sh.ffle model in th. optimization of mach.ne *** weak assumptions and th. generalized linear loss(GLL)structure,we propose a noisy Frank-Wolfe with.sh.ffle model algorith.(NoisyFWS)and a noisy variance-reduced Frank-Wolfe with.th. sh.ffle model algorith.(NoisyVRFWS)by adding calibrated laplace noise under sh.ffling sch.me in th.l_(p)(p∈[1,2])-case,and study th.ir privacy as well as utility guarantees for th. h.lder smooth.ess *** particular,th. privacy guarantees are mainly ach.eved by using advanced composition and privacy amplification by *** utility bounds of th. Noisy FWS and NoisyVRFWS are analyzed and obtained th. optimal ex.ess population risksO(n-(1+α/4α+log(d)√log(1/δ)/n∈and O(n-1+α/4α+log(d)√log1(+δ)/n^(2)∈with.gradient complex.ty O(n(1+α)^(2)/4α^(2)forα∈[1/√3,1].It turns out th.t th. risk rates under sh.ffling sch.me are a nearly-dimension independent rate,wh.ch.is consistent with.th. previous work in some *** addition,th.re is a vital tradeoff between(α,L)-h.lder smooth.ess GLL and th. gradient *** linear gradient complex.ty O(n)is sh.wed by th. parameterα=1.

关键词： differential privacy Frank-Wolfe algorith. privacy amplification sh.ffle model

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