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Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： gürel Cam Ali günen Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Mechanical Engineering31200 Iskenderun-HatayTurkey Iskenderun Technical University Faculty of Engineering and Natural SciencesDepartment of Metallurgy and Materials Engineering31200 Iskenderun-HatayTurkey

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport ***,their widespread application is hindered by their low formability at room temperature due to limited slip *** Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high *** casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain *** metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast ***,MAM is a promising technique to produce Mg alloy *** energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive ***,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this *** review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and ***,the predominant imperfections,notably inhomo

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing(WAAM) 3-D printing High deposition rate

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Effect of an Airbag-selective Portal Vein Blood Arrester on the Liver after Hepatectomy:A New Technique for Selective Clamping of the Portal Vein

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Current Medical Science 2024年第2期44卷 380-390页

作者： Ce-xiong FU Xiao-ri QIN Jin-song CHEN Jie ZHONg Yu-xu XIE Bi-dan LI Qing-qing FU Fang LI Jin-fang ZHENg Department of Hepatobiliary and Pancreatic Surgery Hainan General HospitalHainan Affiliated Hospital of Hainan Medical UniversityHaikou 570311China University of South China Hengyang 421001China Department of gastroenterology Gastroenterology Endoscopy CenterHainan General HospitalHainan Affiliated Hospital of Hainan Medical UniversityHaikou 57031lChina Center of Clinical Laboratory Hainan General HospitalHainan Affiliated Hospital of Hainan Medical UniversityHaikou 570311China Department of Radiology Hainan General HospitalHainan Affiliated Hospital of Hainan Medical UniversityHaikou 570311China

Objective:A novel technique was explored using an airbag-selective portal vein blood arrester that circumvents the need for an intraoperative assessment of anatomical variations in patients with complex intrahepatic space-occupying ***:Rabbits undergoing hepatectomy were randomly assigned to 4 groups:intermittent portal triad clamping(PTC),intermittent portal vein clamping(PVC),intermittent portal vein blocker with an airbag-selective portal vein blood arrester(APC),and without portal blood occlusion(control).Hepatic ischemia and reperfusion injury were assessed by measuring the 7-day survival rate,blood loss,liver function,hepatic pathology,hepatic inflammatory cytokine infiltration,hepatic malondialdehyde levels,and proliferating cell nuclear antigen ***:Liver damage was substantially reduced in the APC and PVC *** APC animals exhibited transaminase levels similar to or less oxidative stress damage and inflammatory hepatocellular injury compared to those exhibited by the PVC *** was significantly higher in the control group than in the other *** APC group had less bleeding than the PVC group because of the avoidance of portal vein skeletonization during ***,more operative time was saved in the APC group than in the PVC ***,the total 7-day survival rate in the APC group was higher than that in the PTC ***:Airbag-selective portal vein blood arresters may help protect against hepatic ischemia and reperfusion injury in rabbits undergoing partial *** technique may also help prevent liver damage in patients requiring hepatectomy.

关键词： hepatectomy portal vein hepatic damage selective clamping

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Recent research in mechanical properties of geopolymer-based ultrahigh-performance concrete:A review

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Defence Technology（防务技术） 2024年第2期32卷 67-88页

作者： g.Murali Division of Research&Innovation Uttaranchal UniversityDehradun 248007India

Due to the growing need for sustainable and ultra-high-strength construction materials,scientists have created an innovative ultra-high-performance concrete called geopolymer based ultra-highperformance concrete(gUHPC).Besides,in the last few decades,there have been a lot of explosions and ballistic attacks around the world,which have killed many civilians and fighters in border *** this context,this article reviews the fresh state and mechanical properties of ***,the ingredients of gUHPC and fresh properties such as setting time and flowability are briefly ***,the review of compressive strength,flexure strength,tensile strength and modulus of elasticity of fibrous ***,the blast and projectile impact resistance performance was ***,the microstructural characteristics were reviewed using the scanning electron microscope and X-ray Powder *** review outcome reveals that the mechanical properties were increased when 30%silica fume was added to a higher dose of steel fibre to improve the microstructure of *** is hypothesized that the brittleness of gUHPC was mitigated by adding 1.5%steel fibre reinforcement,which played a role in the decrease of contact explosion cratering and *** the need for cement in gUHPC was a key factor in the review,indicating a promising potential for lowering carbon ***,gUHPC research is still in its early stages,so more study is required before its full potential can be utilized.

关键词： Mechanical properties Blast Projectile impact Fibre geopolymer Silica fume Alkaline activators

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基于催化裂化家族技术发展新型炼化一体化

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化学研究与应用 2024年第9期36卷 1961-1967页

作者：许日中海油惠州石化有限公司广东惠州516086

重油流化催化裂化(RFCC)是重油轻质化核心工艺和车用燃料主要来源,近30年来,中国石化(Sinopec)石油化工科学研究院(riPP)主研并工业化了十五余项FCC家族系列专有技术,为RFCC作为重油轻质化和烯烃、芳烃化的炼化核心工艺奠定了技术基础... 详细信息

重油流化催化裂化(RFCC)是重油轻质化核心工艺和车用燃料主要来源,近30年来,中国石化(Sinopec)石油化工科学研究院(riPP)主研并工业化了十五余项FCC家族系列专有技术,为RFCC作为重油轻质化和烯烃、芳烃化的炼化核心工艺奠定了技术基础。针对环境保护对燃油的要求高,且炼制原料重质化、劣质化和炼油过剩而化工品紧缺的现状,结合对FCC家族技术的评述,提出以FCC家族系列技术为核心的一体化技术方案,包括:上游原料加氢预处理、下游油品质量升级、烯烃或芳烃深加工等规模相匹配的装置群,构成重油加工联合装置,实现了环境保护要求和“减油增化”目的,形成新型炼化一体化。

关键词：重油催化裂化环境保护 FCC家族系列技术联合装置炼化一体化

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Performance of water-coupled charge blasting under different in-situ stresses

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Journal of Central South University 2024年第7期31卷 2300-2320页

作者： ZHOU Zi-long WANg Zhen CHENg Rui-shan CAI Xin LAN ri-yan School of Resources and Safety Engineering Central South UniversityChangsha 410083China Center for Infrastructural Monitoring and Protection School of Civil and Mechanical EngineeringCurtin UniversityBentleyAustralia guangxi Xinfazhan Communication group Co. Ltd.Nanning 530000China

Water-coupled charge blasting is a promising technique to efficiently break rock *** this study,numerical models of double boreholes with water-coupled charge are established using LS-DYNA and are calibrated by the tests of rock masses subjected to explosion loads to examine its *** crack levels of rock mass induced by water-coupled charge blasting and air-coupled charge blasting are first *** is found that water-coupled charge blasting is more appropriate to fracture deep rock mass than air-coupled charge *** addition,the effects of rock properties,water-coupled charge coefficients,and borehole connection angles on the performance of water-coupled charge blasting are *** results show that rock properties and water-coupled charge coefficients can greatly influence the crack and fragmentation levels of rock mass induced by water-coupled charge blasting under uniform and non-uniform in-situ ***,changing borehole-connection angles can only affect crack and fragmentation levels of rock mass under non-uniform in-situ stresses but barely affect those under uniform in-situ stresses.A formula is finally proposed by considering the above-mentioned factors to provide the design suggestion of water-coupled charge blasting to fracture rock mass with different in-situ stresses.

关键词： water-coupled blasting in-situ stress water-coupled charge coefficient rock type borehole-connection angle

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Modulated noble metal/2D MOF heterostructures for improved hydrogen storage of MgH_(2)

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Rare Metals 2024年第4期43卷 1672-1685页

作者： Zeng-Yi Li Li-Xian Sun Fen Xu Yu-Mei Luo Yong-Peng Xia Sheng Wei Chen-Chen Zhang ri-guang Cheng Chao-Feng Ye Meng-Yuan Liu Ju-Lan Zeng Zhong Cao Hong-ge Pan School of Material Science and Engineering Guilin University of Electronic TechnologyGuilin541004China School of Chemistry and Chemical Engineering Changsha University of Science and TechnologyChangsha410114China Institute of Science and Technology for New Energy Xi’an Technological UniversityXi’an710021China

The conjugation of external species with twodimensional(2D)materials has broad application *** this study,we have explored the potential of noble metal/2D MOF heterostructures in hydrogen ***,the MgH_(2)-Ni-MOF@Pd system has shown remarkable hydrogen desorption/sorption performances,starting to liberate hydrogen at 1810C,which is 2300C lower than that of pristine *** the catalytic effect of Ni-MOF@Pd,the dehydrogenation apparent activation energy of MgH2 is noticeably decreased from(133.5±17.5)to(34.58±1.87)kJ·moL^(-1),and the hydrogenation apparent activation energy is reduced from(70.41±7.43)to(25.78±4.64)kJ·moL^(-1),which is lowered by 63.4%.The fully-dehydrogenated MgH2-NiMOF@Pd composite rapidly uptakes hydrogen,with 2.62wt%at 100℃and 6.06 wt%at 150℃within 300 s,*** mechanism analysis of MgH2 catalyzed by Ni-MOF@Pd has revealed that the transformation of Mg_2Ni and Mg_2NiH_4 could act as a"hydrogen pump",providing numerous channels for fast diffusion and transport of hydrogen ***,in the dehydrogenation process,the element Pd reacts with MgH_(2)to form the MgPd alloy phase,which makes MgH_(2)take precedence to decompose through the Mg-Pd alloy rather than self-decomposition,further reducing thermal stability and improving de/hydrogenation *** synergistic effect of Mg-Pd,Mg_2Ni,and the special ultra-thin 2D sheet structure of the additive is the main reason for the good hydrogen storage property of MgH_(2)-Ni-MOF@*** findings provide inspiration for designing efficient multifunctional additives with unique morphologies to optimize the hydrogen desorption/sorption behaviors of hydrogen storage materials.

关键词： Hydrogen storage Magnesium hydride 2D metal-organic framework nanosheets Ni/Pd Synergistic catalysis

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Nitrogen mineralization in the oldest climax communities in the eastern Mediterranean region

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Journal of Forestry Research 2024年第1期35卷 213-228页

作者： Fatma Selcen Sakar gürcan güleryüz Department of Biology Section Ecology GörükleGraduate School of Natural and Applied ScienceUniversity of Bursa Uludağ16059 NilüferBursaTurkey Department of Biology Section Ecology GörükleFaculty of Science and ArtsUniversity of Bursa Uludağ16059 NilüferBursaTurkey

In this study,we investigated how tree species affect N mineralization in connection to some soil properties and seconder metabolite levels of litter,in the soil of the old-est native forest *** the oldest pure communi-ties of Pinus nigra(PN),Fagus orientalis(FO),and Abies bornmuelleriana(AB)in the mountain range of Mount Uludağ,Bursa,Turkey,annual net yield and N mineraliza-tion in the 0-5-and 5-20-cm soil layers were determined in a field incubation study over 1 *** locations were chosen from 1300 to 1600 m a.s.l.,and moisture content(%),pH,water-holding capacity(%),organic C,total N,and C/N ratio,and annual net mineral N yield of the soil and hydro-lyzed tannic acid and total phenolic compounds in litter were compared for these forest *** had the highest annual net Nmin yield(43.9±4.8 kg ha^(-1) a^(-1)),*** the lowest(30.5±4.2 kg ha^(-1) a^(-1)).Our findings show that in the oldest forest ecosystems,the seasonal soil moisture content and tree species play an essential role in N cycling and that hydrolyzed tannic acids and total phenolic compounds effectively control N *** acid and total phenolics in the litter were found to inhibit nitrification,but total phenolics were found to stimulate ammonification.

关键词： Oldest forest communities Nitrogen mineralization Nitrification Tannic acid Total phenolic Litter

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Microstructure and properties of Cu matrix composites reinforced with surface-modified Kovar particles

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Transactions of Nonferrous Metals Society of China 2024年第10期34卷 3251-3264页

作者： Tao MENg ri-chu WANg Zhi-yong CAI Ying-jun YAO School of Materials Science and Engineering Central South UniversityChangsha 410083China Key Laboratory of Electronic Packaging and Advanced Functional Materials Central South UniversityChangsha 410083China

The thermal conductivity of Cu/Kovar composites was improved by suppressing element diffusion at the interfaces through the formation of FeWO_(4)coating on the Kovar particles via vacuum *** matrix composites reinforced with unmodified(Cu/Kovar)and modified Kovar(Cu/Kovar@)particles were prepared by hot *** results demonstrate that the interfaces of Cu/FeWO_(4)and FeWO_(4)/Kovar in the Cu/Kovar@composites exhibit strong bonding,and no secondary phase is *** presence of FeWO_(4)impedes interfacial diffusion within the composite,resulting in an increase in grain size and a decrease in dislocation *** surface modification of the Kovar particle,the thermal conductivity of Cu/Kovar@composite is increased by 110%from 40.6 to 85.6 W·m^(-1)·K^(-1).Moreover,the thermal expansion coefficient of the Cu/Kovar@composite is 9.8×10^(-6)K^(-1),meeting the electronic packaging requirements.

关键词： electronic packaging material Cu/Kovar composite surface modification thermal conductivity

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A multi-platform analysis of human gingival crevicular fluid reveals ferroptosis as a relevant regulated cell death mechanism during the clinical progression of periodontitis

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International Journal of Oral Science 2024年第2期16卷 265-279页

作者： Alfredo Torres M.Angélica Michea Ákos Végvári Marion Arce Valentina Pérez Marcela Alcota Alicia Morales Rolando Vernal Mauricio Budini Roman A.Zubarev Fermín E.gonzález Laboratory of Experimental Immunology&Cancer Faculty of DentistryUniversity of ChileSantiagoChile Department of Conservative Dentistry Faculty of DentistryUniversity of ChileSantiagoChile Division of Chemistry I Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden Periodontal Biology Laboratory Faculty of DentistryUniversidad de ChileSantiagoChile Laboratory of Cellular and Molecular Pathology Institute for Research in Dental SciencesFaculty of DentistryUniversity of ChileSantiagoChile

Ferroptosis is implicated in the pathogenesis of numerous chronic-inflammatory diseases,yet its association with progressive periodontitis remains *** investigate the involvement and significance of ferroptosis in periodontitis progression,we assessed sixteen periodontitis-diagnosed *** progression was clinically monitored over twelve weeks via weekly clinical evaluations and gingival crevicular fluid(gCF)collection was performed for further *** metrics,proteomic data,in silico methods,and bioinformatics tools were combined to identify protein profiles linked to periodontitis progression and to explore their potential connection with *** western blot analyses validated key ***,a single-cell RNA sequencing(scRNA-seq)dataset(gSE164241)for gingival tissues was analyzed to elucidate cellular dynamics during periodontitis *** progression was identified as occurring at a faster rate than traditionally *** samples from progressing and non-progressing periodontal sites showed quantitative and qualitatively distinct proteomic *** addition,specific biological processes and molecular functions during progressive periodontitis were revealed and a set of hub proteins,including SNCA,CA1,HBB,SLC4A1,and ANK1 was strongly associated with the clinical progression status of ***,we found specific proteins-drivers or suppressors-associated with ferroptosis(SNCA,FTH1,HSPB1,CD44,and gCLC),revealing the co-occurrence of this specific type of regulated cell death during the clinical progression of ***,the integration of quantitative proteomic data with scRNA-seq analysis suggested the susceptibility of fibroblasts to *** analyses reveal proteins and processes linked to ferroptosis for the first time in periodontal patients,which offer new insights into the molecular mechanisms of progressive periodontal *** findings may le

关键词： finding progression faster

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Shell-model representations of the microscopic version of the Bohr-Mottelson collective model

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Communications in Theoretical Physics 2024年第8期76卷 79-90页

作者： H g ganev Joint Institute for Nuclear Research DubnaRussia Institute of Mechanics Bulgarian Academy of SciencesSofiaBulgaria

The structure of the irreducible collective spaces of the group Sp(12,R),which many-particle nuclear states are classified according to the chain Sp(12,R)⊃U(6)⊃SO(6)⊃SU_(pn)(3)⊗SO(2)⊃SO(3)of the proton-neutron symplectic model(PNSM),is considered in *** chain of the PNSM was recently shown to correspond to a microscopic shell-model version of the Bohr-Mottelson collective *** construction of the relevant shell-model representations of the Sp(12,R)group along this chain is considered for three nuclei with varying collective properties and from different mass *** is shown that the SU_(pn)(3)basis states of the Sp(12,R)representations belonging to the SO(6)irreps with seniorityυ≥υ0,withυ0 denoting the maximal seniority SO(6)irrep contained in the Sp(12,R)bandhead,are always Pauli allowed,but organized in a different way into different SO(6)*** is in contrast to the case of filling the levels of the standard three-dimensional harmonic oscillator and using the plethysm *** the SU_(pn)(3)multiplets withinυ<υ0 are not all Pauli forbidden,it is safe to discard *** results obtained in the present work are important for the practical application of the microscopic version of the Bohr-Mottelson collective model.

关键词： microscopic shell-model version of the Bohr-Mottelson model proton-neutron symplectic model Sp(12,R)dynamical algebra shell-model representations

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