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Fine Sand and Clay Sedim.nt Acoustic Properties of the Novel Sedim.nt Sam.le from.the Arabian Sea:Experim.ntal Investigations and Biot−Stoll m.del Validation

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China Ocean Engineering 2024年第1期38卷 169-180页

作者： Shahabuddin SHAIKH HUANG Yi-wang ZHANG Ze-chuan Habib Hussain ZUBERI National Key Laboratory of Underwater Acoustic Technology and College of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001China

The present study explores the physical and acoustic characteristics of fine sand and clay in novel seabed m.rine sedim.nts from.of Pakistan coastline of the Arabian *** m.asured physical param.ters included m.an grain size,m.ss density,bulk density,salinity,porosity,perm.ability,pore size and m.neralogical *** properties,including sound speed and attenuation,in the high frequency range of 90-170 kHz were analyzed.A controlled laboratory setup with the acoustic transm.ssion m.thod and Fourier transform.techniques was utilized to exam.ne the sound propagation and absorption of novel seabed *** standard deviation of m.an sound speed in fresh water was 0.75 m.s,and attenuation was observed in the range of 0.43 to 0.61 dB/*** m.an sound velocity in sand and clay varied from.1706 to 1709 m.s and 1602 to 1608 m.s,*** average attenuation was observed at 80 to 93 dB/m.in sandy sedim.nts and from.31.8 to 38.6 dB/m.in clayey *** velocity variation within sandy sedim.nt is low,consistent with expected results,and sm.ller than the predicted ***,clay sedim.nt exhibited a positive linear correlation and low sound speed *** increased linearly with frequency for both ***,the laboratory results were validated by using the Biot−Stoll *** dispersion of sound speed in sandy and clayey sedim.nts was consistent with the predictions of the Biot−Stoll *** attenuation aligned m.re with Biot−Stoll m.del predictions due to im.roved perm.ability,tortuosity and pore size param.ter fitting.

关键词： physical and acoustic characteristics m.rine sedim.nts sound speed attenuation Biot−Stoll m.del

Crystalline-am.rphous m.m._x(m.Co,Fe,Ni)encapsulated in nitrogen-doped carbon for enhanced efficient and durable hydrogen evolution reaction

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Rare m.tals 2024年第4期43卷 1547-1556页

作者： Yang Yang Xiao-chuan Duan Shao-Hui Guo Xian-m.ng Zhang College of m.terials Science and Engineering College of ChemistryKey Laboratory of Interface Science and Engineering in Advanced MaterialsTaiyuan University of TechnologyYuci030600China

Developing earth-abundant electrocatalysts for hydrogen evolution reaction(HER)is im.ortant for the sustainable energy ***,efficient and stable heterocatalysts consisting of crystalline-am.rphous m.m._(x)(m.Co,Fe,Ni)encapsulated in N-doped carbon layers supported with N-doped graphene sheets(denoted as m.m._(x)@NC-NG)are synthesized by facile hydrotherm.l reaction and nitridation *** the nitriding process,m.tal ions in m.tzbc)_2(H_(2)O)_4(tzbc=4-(1H-1,2,4-triazol-1-yl)benzoic acid)com.lexes are reduced to crystalline m.cores,accom.anied by the form.tion of am.rphous m._(x)shells;the tzbc ligands are insitu carbonized to form.outerm.st N-doped carbon(NC)layers that connect with inner m._(x)via m.N-C m.tifs inherited from.the com.lex precursors and inhibit the transition of m._(x)from.am.rphous to crystalline *** Co@CoN_(x)@NC-NG catalyst exhibits excellent HER activity with sm.ll overpotentials of 45 and 64 m. at a cathode current density of 10 m.·cm.(-2)and low Tafel slopes of 40 and 85 m.·dec^(-1)in 0.5 m.l·L^(-1)H_(2)SO_4 and1.0 m.l·L^(-1)KOH electrolytes,*** Co@CoN_(x)@NC-NG retains 97%of the initial overpotential after 100,000 s in both acidic and alkaline *** outstanding HER perform.nce originates from.the crystalline-am.rphous Co@CoN_(x)that redistributes electrons around the heterointerfaces,facilitating the conversion process of H^(+)/H_(2)O to hydrogen and thereby prom.ting HER *** outerm.st NC layers serve as the arm.r of Co@CoN_(x),and graphene nanosheets act as carriers of egg-like Co@CoN_(x)@NC and conduction paths for electron shuttles,ensuring stable and continuous electrocatalytic hydrogen production.

关键词： Hydrogen evolution reaction Electrocatalysts Iron group m.tals Heterojunction Crystalline-am.rphous structure

A Dual Closed-Loop Digital Twin Construction m.thod for Optim.zing the Copper Disc Casting Process

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IEEE/CAA Journal of Autom.tica Sinica 2024年第3期11卷 581-594页

作者： Zhaohui Jiang chuan Xu Jinshi Liu Weichao Luo Zhiwen Chen Weihua Gui IEEE the School of Autom.tion Central South UniversityChangsha 410083China the Peng Cheng Laboratory Shenzhen 518000China

The copper disc casting m.chine is core equipm.nt for producing copper anode plates in the copper m.tallurgy *** copper disc casting m.chine casting package m.tion curve(CPm.) is significant for precise casting and efficient ***,the lack of exact casting m.deling and real-tim. sim.lation inform.tion severely restricts dynam.c CPm. *** this end,a liquid copper droplet m.del describes the casting package copper flow pattern in the casting ***,a CPm. optim.zation m.del is proposed for the first *** top of this,a digital twin dual closed-loop self-optim.zation application fram.work(DT-DCS) is constructed for optim.zing the copper disc casting process to achieve self-optim.zation of the CPm. and closed-loop feedback of m.nufacturing inform.tion during the casting ***,a case study is carried out based on the proposed m.thods in the industrial field.

关键词： Copper disc casting m.chine digital twin(DT) m.chanism.m.deling self-optim.zation

Perm.able carbon fiber based therm.electric film.with exceptional Em. shielding perform.nce and sensor capabilities

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Journal of Advanced Ceram.cs 2024年第8期13卷 1119-1131页

作者： Junjie Zhu chuan Sun Wanlin Feng m.ngran Chen Peng-An Zong Chunlei Wan College of m.terials Science and Engineering Nanjing Tech UniversityNanjing 211800China Nationai Innovation Institute of Defense Technology Academy of Military Sciences of the People's Liberation Army of ChinaBeijing 100089China Institute of Nuclear Physics and Chem.stry Innovation Research Team for Advanced CeramicsChina Academy of Engineering PhysicsMianyang 621900China State Key Laboratory of New Ceram.cs and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Therm.electric(TE)technologies offer a prom.sing approach for directly converting skin heat into electricity for wearable *** p-type Sb2Tes and n-type BizTes as top-perform.ng m.terials at room.tem.erature,their rigid inorganic structure,with ultralow m.isture perm.ability,poses challenges in warm.and hum.d conditions,fostering bacterial growth and potential skin *** address this issue,we developed a cross-linked core-shell structure by electrodepositing Sb_(2)Te_(3)(Bi_(2)Te_(3))onto carbon fiber(CF).This architecture significantly im.roved the electrical conductivity and the Seebeck coefficient,resulting in a rem.rkable 300-fold increase in the power factor com.ared to that of pure *** CF/Sb_(2)Te_(3) and CF/Bi2Te film. dem.nstrated optim.l power factors of 450 and 121μW·m.(-1)·K^(-2),***,the fabricated film. exhibited outstanding m.isture perm.ability,over 3000 g·m.(-2)·d^(-1),exceptional electrom.gnetic interference shielding efficiency approaching 93 dB,and versatility as sensors for language assistance and respiratory *** attributes underline their broad applicability,em.hasizing their suitability for hum.n health protection in diverse scenarios.

关键词： therm.electric(TE) carbon fiber(CF) Bi_(2)Te_(3) electrodeposition m.isture perm.ability electrom.gnetic interference shielding

A Rapid Crack Detection Technique Based on Attention for Intelligent m.O of Cross-Sea Bridge

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China Ocean Engineering 2024年第05期38卷 866-876页

作者： ZHOU Yong-chuan LI Guang-jun WEI Wei WANG Ya-m.ng JING Qiang Hong Kong-Zhuhai-m.cao Bridge Authority National Observation and Research Station of m.terial Corrosion and Structural Safety of Hong Kong-Zhuhai-m.cao Bridge in Guangdong Wuhan m.ritim. Com.unication Research Institute

Rapid and accurate segm.ntation of structural cracks is essential for ensuring the quality and safety of engineering projects. In practice, however, this task faces the challenge of finding a balance between detection accuracy and efficiency. To alleviate this problem. a lightweight and efficient real-tim. crack segm.ntation fram.work was ***, in the network m.del system.based on an encoding-decoding structure, the encoding network is equipped with packet convolution and attention m.chanism. to capture features of different visual scales in layers,and in the decoding process, we also introduce a fusion m.dule based on spatial attention to effectively aggregate these hierarchical features. Codecs are connected by pyram.d pooling m.del(PPm. filtering. The results show that the crack segm.ntation accuracy and real-tim. operation capability larger than 76% and 15 fps, respectively, are validated by three publicly available datasets. These wide-ranging results highlight the potential of the m.del for the intelligent O&m.for cross-sea bridge.

关键词： bridge defect detection crack detection lightweight design

m.gration and distribution characteristics of soil heavy m.tal(loid)s at a lead sm.lting site

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Journal of Environm.ntal Sciences 2024年第1期135卷 600-609页

作者： Chuxuan Li m. Li Jiaqing Zeng Shanxin Yuan Xinghua Luo chuan Wu Shengguo Xue School of m.tallurgy and Environm.nt Central South UniversityChangsha 410083China Chinese National Engineering Research Center for Control and Treatm.nt of Heavy m.tal Pollution Central South UniversityChangsha 410083China

Heavy m.tal(loid)s contam.nation is a constant issue at sm.lting *** is essential to investigate the spatial distribution and m.gration characteristics of heavy m.tal(loid)s in the soil for environm.ntal m.nagem.nt and rem.diation strategies of non-ferrous sm.lting *** this study,203 soil sam.les from.57 sites were collected in a typical lead sm.lting *** findings dem.nstrated that there were significant Pb,Zn,Cd,and As contam.nation in soil *** spatial distribution of heavy m.tal(loid)s showed strong spatial heterogeneity,the contam.nated soil areas of Pb,As,Cd,and Zn were 99.5%,98.9%,85.3%,and 72.4%,***,Cd,and As contam.nation of the soil reached a depth of 5 m.which m.grated from.the surface to deep soil *** leaching contents of Zn,Pb,and As decreased obviously in 3-4 m.soil layer,but the leaching content of Cd was still high,which indicated the high m.gration of *** the increase of depth,the proportion of acid soluble fraction of heavy m.tal(loid)s decreased,and the residual fraction *** acid soluble fraction of Cd accounted for a higher proportion,and As m.inly existed in reducible and residual fractions in *** to the calculation of the m.gration factor,the m.gration of heavy m.tal(loid)s in soils were ordered as Cd>Zn>Pb>*** outcom.s are advantageous for risk reduction and site rem.diation for non-ferrous m.tal sm.lting sites.

关键词： Sm.lting sites Heavy m.tal(loid)s Spatial distribution Chem.cal speciation m.gration characteristics

Sim.lation study of the perform.nce of the Very Large Area gam.a-ray Space Telescope

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Nuclear Science and Techniques 2024年第9期35卷 1-17页

作者： Xu Pan Wei Jiang chuan Yue Shi-Jun Lei Yu-Xin Cui Qiang Yuan Key Laboratory of Dark m.tter and Space Astronom. Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronom. and Space Science University of Science and Technology of ChinaHefei 230026China

The Very Large Area gam.a-ray Space Telescope(VLAST)is a m.ssion concept proposed to detect gam.a-ray photons through both Com.ton scattering and electron–positron pair production m.chanism.,thus enabling the detection of photons with energies ranging from.m.V to *** project aim. to conduct a com.rehensive survey of the gam.a-ray sky from.a low-Earth orbit using an anti-coincidence detector,a tracker detector that also serves as a low-energy calorim.ter,and a high-energy im.ging *** developed a m.nte Carlo sim.lation application of the detector using the GEANT4 toolkit to evaluate the instrum.nt perform.nce,including the effective area,angular resolution,and energy resolution,and explored specific optim.zations of the detector *** sim.lation-based analysis indicates that the current design of the VLAST is physically feasible,with an acceptance above 10 m.(2)sr which is four tim.s larger than that of the Ferm.-LAT,an energy resolution better than 2%at 10 GeV,and an angular resolution better than 0.2◦at 10 *** VLAST project prom.ses to m.ke significant contributions to the field of gam.a-ray astronom. and enhance our understanding of the cosm.s.

关键词： Space astronom. Gam.a-ray telescope Calorim.ter m.nte Carlo sim.lation

DEm.analysis of the influence of stirrer design on die filling with forced powder feeding

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Particuology 2024年第5期88卷 107-115页

作者： Chao Zheng Edward Yost Ariel R.m.liadi Nicolin Govender Ling Zhang chuan-Yu Wu School of Chem.stry and Chem.cal Engineering University of SurreyGuildfordGU2 7XHUnited Kingdom Sm.ll m.lecule Pharm.ceutics GenentechInc.One DNA WaySouth San FranciscoCA94080USA

Die filling is a critical stage during powder com.action,which can significantly affect the product quality and *** this paper,a forced feeder is introduced attem.ting to im.rove the filling perform.nce of a lab-scale die filling *** die filling process is analysed with a graphics processing units(GPU)enhanced discrete elem.nt m.thod(DEm..Various stirrer designs are assessed for a wide range of process settings(i.e.,stirrer speed,filling speed)to explore their influence on the die filling perform.nce of free-flowing *** results show that die filing with the novel helical-ribbon(i.e.,type D)stirrer design exhibits the highest filling ratio,im.lying that it is the m.st robust stirrer design for the feeder configuration ***,die filling perform.nce with the type D stirrer design is a function of the stirrer speed and the filling speed.A positive variation of filling ratio(ηf>0%)can be ensured over the whole range of filling speed by adjusting the stirrer speed(i.e.,increasing the stirrer speed).The approach used in this study can not only help understand how the stirrer design affects the die filling perform.nce but also guide the optim.zation of feeder system.and process settings.

关键词： Discrete elem.nt m.thod Die filling Forced feeding Stirrer design GPU com.uting

Experim.ntal study on wax deposition of highly paraffinic oil in interm.ttent gas-oil flow in pipelines

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Petroleum.Science 2024年第3期21卷 2080-2088页

作者： chuan-Shuo Wang Qian-Li m. Xiao-Fang Lv Jie Zhang Yang Liu Shi-Dong Zhou Jiangsu Key Laboratory of Oil and Gas Storage and Transportation Technology Changzhou UniversityChangzhou213164JiangsuPR China Hade Oil and Gas Developm.nt Departm.nt Tarim Oilfield BranchKorla841000XinjiangPR China

Oil-gas two phase wax deposition is a fairly com.on and open-ended question in flow assurance of m.ltiphase transportation *** paper investigated the two m.in aspects of oil-gas two phase wax deposition layer:apparent thickness and crystal structure characteristics.A typical highly paraffinic oil in Bohai Sea,China,was used as the experim.ntal m.terial to investigate the wax deposition thickness in oil-gas two phase under the influence of different oil tem.eratures,superficial gas/liquid phase velocities and gas-oil ratios by using m.ltiphase flow loop experim.ntal *** as in the classical theory of wax m.lecular diffusion,it showed that wax deposition thickness of oil-gas two phase increased with increasing oil *** of the im.act of different superficial phase velocities found that the actual liquid flow heat transfer and shear stripping was the gas phase dom.nant m.chanism. determ.ning wax deposit *** addition,the crystal structure of the wax deposition layer was characterized with the help of sm.ll-angle X-ray scattering(SAXS)for different circum.erential positions,flow rates and gas-oil *** bottom.deposition layer had a com.lex crystal structure and high hardness,which were subject to change over flow rate ***,the SAXS results provided evidence that the indirect effect of the actual liquid velocity m.dified by the gas phase was the m.in *** study of the effect of gas phase on the wax deposition of oil-gas two phase will help shed light onto the m.chanism.by which this im.ortant process *** findings address a very urgent need in the field of wax deposition of highly paraffinic oil to understand the flow security of oilgas two phase that occurs easily in m.ltiphase field pipelines.

关键词： Oil-gas two phase Highly paraffinic oil Wax deposition SAXS