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Geometric quality evaluation of three-dimensional printable concrete using computational fluid dynamics

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 963-976页

作者： Weijiu CUI Haijun SUN jiangang ZHOU sheng WANG xinyu shi Yaxin TAO department of Civil Engineering Qingdao University of TechnologyQingdao 266000China Innovation Institute for Sustainable Maritime Architecture research and Technology Qingdao University of TechnologyQingdao 266000China Intelligent Construction Lab Qingdao University of TechnologyQingdao 266000China Shandong Zhaojin Industrial development Co. Ltd.Yantai 264000China Architectural Engineering Institute Weifang Engineering Vocational CollegeWeifang 261000China Qingjian Group Co. Ltd.Qingdao 266000China College of Architecture and Urban Planning Qingdao University of TechnologyQingdao 266000China department of Structural Engineering and Building Materials Ghent UniversityGhent 9000Belgium Institute of Building Materials ETH ZurichZurich 8064Switzerland

The importance of geometrical control of three dimensional(3d)printable concrete without the support of formwork is widely *** this study,a numerical model based on computational fluid dynamics was developed to evaluate the geometrical quality of a 3d printed *** numerical results were compared,using image analysis,with physical cross-sectional sawn *** influence of printing parameters(printing speed,nozzle height,and nozzle diameter)and the rheological behavior of printed materials(yield stress),on the geometrical quality of one printed layer was *** addition,the yield zone of the printed layer was analyzed,giving insights on the critical factors for geometrical control in 3d concrete *** indicated that the developed model can precisely describe the extrusion process,as well as the cross-sectional quality.

关键词： digital fabrication 3d concrete printing geometric quality computational fluid dynamics printing parameters yield stress

Metal-free Optical Pressure Sensor with High Sensitivity and Extensive range

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CSEE journal of Power and Energy Systems 2024年第3期10卷 1291-1300页

作者： Mao ji Meng Huang Haomin Lyu sheng shi Bo Qi Chengrong Li State Key Laboratory of Alternate Electrical Power System with renewable Energy Sources North China Electric Power UniversityBeijing 102206China IEEE CSEE

Pressure monitoring of a transformer oil tank can grasp the pressure change process caused by gas production when severe internal defects occur and take timely measures to ensure the safe operation of the *** pressure sensors generally use metal encapsulation or have an air cavity structure,threatening the transformer’s insulation if it is directly used inside the *** this end,this paper proposes a method for developing a high-sensitivity,large-range,and metallizationfree optical pressure sensing device with temperature *** grating is encapsulated by fluorosilicone rubber and supplemented by an epoxy resin shielding shell on the *** the same time,a double-grating vertical arrangement is adopted to improve pressure measurement sensitivity,further avoiding the influence of temperature rise caused by a defect of the transformer on the measurement result of the *** addition,by optimizing the geometric structure of the internal sensitizing element,pre-stretching length of the fiber grating,gap distance,and other parameters,probe size can be reduced while ensuring the sensor’s *** show the proposed method can meet the requirements of sensor fabrication with different sensitivities and ranges,and to a certain extent,both high sensitivity and extensive ranges can be taken into *** sensitivity of the fabricated prototype is 15 pm/kPa,and the range is about 0.2 *** the same time,the metal-free feature of the sensor makes it suitable for use in various oil-immersed power *** records oil pressure changes caused by oil discharge breakdown,making it sensitive to small pressure changes in early failures.

关键词： Highly sensitive extensive range optical sensing no metallization pressure perception temperature compensation transformer

A low-melting-point metal doping strategy for the synthesis of small-sized intermetallic Pt_(5)Ce fuel cell catalysts

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Nano research 2024年第9期17卷 8112-8118页

作者： Zi-jun Zou shi-Yi Yin Yao Tang sheng-Liang Zhong Lei Wang shi-Long xu Hai-Wei Liang College of Chemistry and Chemical Engineering Jiangxi Normal UniversityNanchang 330022China department of Chemistry University of Science and Technology of ChinaHefei 230026China School of Materials and Chemical Engineering Anhui Jianzhu UniversityHefei 230601China

Carbon-supported platinum-lanthanum(Pt-Ln)intermetallic compound(IMC)nanoparticles with high activity and robust stability have been demonstrated as promising cathode catalysts for proton-exchange membrane fuel ***,the preparation of Pt-Ln IMC catalysts needs high-temperature annealing treatment that inevitably causes nanoparticle sintering,resulting in significant reduction of the electrochemical surface area and mass-based ***,we prepare small-sized M-doped Pt_(5)Ce(M=Ga,Cd,and Sb)IMCs catalysts via a low-melting-point metal doping *** speculate that the doping of low-melting-point metals can facilitate the generation of vacancies in the crystal lattice through thermal activation and thus reduce the kinetic barriers for the formation of intermetallic Pt_(5)Ce *** prepared Ga-doped Pt_(5)Ce catalyst exhibits a higher electrochemical active surface area(81 m^(2)·gPt^(-1))and a larger mass activity(0.45 A·mgPt^(-1)at 0.9 V)over the undoped Pt_(5)Ce and commercial Pt/C *** the membrane electrode assembly test,the Ga-doped Pt_(5)Ce cathode delivers a power density of 0.98 W·cm^(-2)at 0.67 V,along with a voltage loss of only 27 mV at 0.8 A·cm^(-2)at the end of accelerated stability test.

关键词： P5Ce low-melting-point metal small-sized intermetallic compound catalysis fuel cells

Tiered clustering-based management architecture in mega-satellite networks

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Science China(Information Sciences) 2024年第5期67卷 215-227页

作者： Qi HAO di ZHOU Min sheng Yan shi jiandong LI State Key Laboratory of Integrated Service Networks Xidian University

Hybrid orbital networking and the proliferation of satellites raise explosive management complexity in mega-satellite networks(MSNs) and prompt the management architecture to the hierarchy. In this regard, we propose a tiered clustering-based management architecture(TCMA) to realize the high-efficient and low-cost management performance. Specifically, based on the constrained satellite coverage, we derive an expression of the mapping relationship between the required control overhead of the controller interaction,the average path length of the proposed TCMA, and the corresponding number of management tiers and cluster size. The expression can determine the optimal number of tiers of the TCMA by minimizing the required flow table size between controllers, while ensuring high transmission efficiency. We then exhibit the elasticity of the hierarchical TCMA by adding the peer connections at the second-highest management tier to reduce maximum redundant paths. Simulation results verify the effectiveness of the proposed TCMA and illustrate that a 3-tier TCMA is sufficient for thousands of satellites.

关键词： mega-satellite networks hierarchical architecture average hop tiered structure clustering

Alloy strategy to synthesize Pt-early transition metal oxide interfacial catalysts

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Nano research 2024年第4期17卷 3390-3397页

作者： shi-Long xu Hang Nan Wanqun Zhang Yue Lin sheng-Qi Chu Hai-Wei Liang Hefei National research Center for Physical Sciences at the Microscale Department of ChemistryUniversity of Science and Technology of ChinaHefei 230026China School of Materials and Chemical Engineering Anhui Jianzhu UniversityHefei 230601China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

Metal oxide supported metal catalysts show promising catalytic performance in many industry-relevant ***,the enhancement of performance is often limited by the insufficient metal/metal oxide *** this work,we demonstrate a general synthesis of Pt-early transition metal oxide(Pt-MO_(x),M=Ti,Zr,V,and Y)catalysts with rich interfacial sites,which is based on the air-induced surface segregation and oxidation of M in the supported Pt-M alloy *** characterizations verify the dynamic structural response of Pt-M alloy catalysts to air and the formation of Pt-MO_(x) catalysts with abundant interfacial *** prepared Pt-TiO_(x) interfacial catalysts exhibit improved performance in hydrogenation reactions of benzaldehyde,nitrobenzene,styrene,and furfural,as a result of the heterolytic dissociation of H_(2) at Pt-metal oxide interfacial sites.

关键词： Pt-early transition metal oxide interfacial catalyst alloy oxidation strategy interfacial sites hydrogenation reactions heterolytic dissociation

The influence of yttrium and manganese additions on the degradation and biocompatibility of magnesium-zinc-based alloys:In vitro and in vivo studies

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journal of Magnesium and Alloys 2024年第2期12卷 608-624页

作者： Lei shi Yang Yan Chun-sheng Shao Kun Yu Bo Zhang Liang-jian Chen Third xiangya Hospital Central South UniversityChangsha 410013China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China School of Materials Science and Engineering Central South UniversityChangsha 410083China department of Mechanical Engineering City University of Hong KongHong KongChina

The repair and regeneration of bone defects are highly challenging orthopedic ***,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human *** aim of our study is to develop a magnesium alloy with a controllable degradation that can closely match bone tissue to help injuries heal in vivo and avoid cytotoxicity caused by a sudden increase in ion *** this study,we prepared and modified Mg-3Zn,Mg-3Zn-1Y,and Mg-2Zn-1Mn by hot extrusion,and used Mg-2.5Y-2.5Nd was as a *** then investigated the effect of additions of Y and Mn on alloys'*** results show that Mn and Y can improve not only compression strength but also corrosion *** alloy Mg-2Zn-1Mn demonstrated good cytocompatibility in vitro,and for this reason we selected it for implantation in *** degraded Mg-2Zn-1Mn implanted a bone defect area did not cause obvious rejection and inflammatory reaction,and the degradation products left no signs of damage to the heart,liver,kidney,or ***,we find that Mg-2Zn-1Mn can promote an osteoinductive response in vivo and the formation of bone regeneration.

关键词： Magnesium alloy Biodegradation Biocompatibility Bone regeneration Bone defect repair

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One-step calcination synthesis of interface-coherent crystallized and surface-passivated LiNi_(0.5)Mn_(1.5)O_(4) for high-voltage lithium-ion battery

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Nano research 2024年第5期17卷 4192-4202页

作者： Min xu Bifu sheng Yong Cheng junjie Lu Minfeng Chen Peng Wang Bo Liu jizhang Chen xiang Han Ming-sheng Wang Siqi shi College of Materials Science and Engineering Co-Innovation Center of Efficient Processing and Utilization of Forest ResourcesNanjing Forestry UniversityNanjing 210037China State Key Laboratory of Physical Chemistry of Solid Surfaces College of MaterialsXiamen UniversityXiamen 361005China College of Mathematics and Physics Jinggangshan UniversityJi’an 343009China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Western digital Corporation 951 Sandisk DrMilpitasCA 95035USA

LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)with a spinel crystal structure presents a compelling avenue towards the development of economic cobalt-free and high voltage(~5 V)lithium-ion ***,the elevated operational voltage of LNMO gives rise to pronounced interfacial interactions between the distorted surface lattices characterized by jahn-Teller(j-T)distortions and the electrolyte ***,a localized crystallized coherent LaNiO_(3) and surface passivated Li_(3)PO_(4) layer is deposited on LNMO via a one-step calcination *** evidenced by transmission electron microscopy(TEM),time-of-flight secondary ion mass spectrometry(ToF-SIMS)and density functional theory(dFT)calculation,the epitaxial growth of LaNiO_(3) along the LNMO lattice can effectively stabilize the structure and inhibit irreversible phase transitions,and the Li_(3)PO_(4) surface coating can prevent the chemical reaction between HF and transition metals without sacrificing the electrochemical *** addition,the ionic conductive Li_(3)PO_(4) and atomic wetting inter-layer enables fast charge transfer transport ***,the LNMO material enabled by the lattice bonding and surface passivating features,demonstrates high performance at high current densities and good capacity retention during long-term *** rational design of interface coherent engineering and surface coating layers of the LNMO cathode material offers a new perspective for the practical application of high-voltage lithium-ion batteries.

关键词： high-voltage cathode interface-coherent surface passivating electrochemical performance

Universal and efficient hybrid modeling and direct slicing method for additive manufacturing processes

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Advances in Manufacturing 2024年第2期12卷 300-316页

作者： Sen-Lin Wang Li-Chao Zhang Chao Cai Ming-Kai Tang Si Chen jiang Huang Yu-sheng shi State Key Laboratory of Materials Processing and die and Mould Technology Huazhong University of Science and TechnologyWuhan430074People’s Republic of China School of Machinery and Automation Wuhan University of Science and TechnologyWuhan430081People’s Republic of China

Model design and slicing contour generation in additive manufacturing(AM)data processing face challenges in terms of efficiency and scalability when stereolithography files generated by complex functionally graded structures have millions of *** paper proposes a hybrid modeling and direct slicing method for AM to efficiently construct and handle complex three-dimensional(3d)*** 3d solids,including conformal multigradient structures,were uniformly described using a small amount of data via signed distance *** hybrid representations were quickly discretized into numerous disordered directed lines using an improved marching squares *** establishing a directional HashMap to construct the topological relationship between lines,a connecting algorithm with linear time complexity is proposed to generate slicing contours for *** method replaces the mesh reconstruction and Boolean operation stages and can efficiently construct complex conformal gradient models of arbitrary topologies through hybrid ***,the time and memory consumption of direct slicing are much lower than those of previous methods when handling hybrid models with hundreds of millions of faces after mesh reconstruction.

关键词： Additive manufacturing(AM) Hybrid modeling direct slicing Signed distance field

Greatly enhanced corrosion/wear resistances of epoxy coating for Mg alloy through a synergistic effect between functionalized graphene and insulated blocking layer

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journal of Magnesium and Alloys 2024年第1期12卷 332-344页

作者： Z.Y.xue x.j.Li j.H.Chu M.M.Li d.N.Zou L.B.Tong School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China State Key Laboratory of Advanced design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China

The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various *** conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient *** the current study,we design a double-layer epoxy composite coating on Mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly *** outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)*** FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier *** Ce film connects the outer layer with the substrate,showing the transition *** corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare Mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling *** synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of Mg alloys.

关键词： Mg alloy Functionalized graphene Epoxy coating Corrosion/wear resistance Blocking layer

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