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Multi-physical fields distribution in billet during helical electromagnetic stirring:A numerical simulation research

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China Foundry 2024年第1期21卷 51-59页

作者： Dong Pan Qing-tao Guo Kai-lun Zhang Fu-zhi.yu yu-ying Li.yu-bao Xiao State Key Laboratory of Metal Materials for Marine Equipment and Application Anshan 114009LiaoningChina Ansteel Beijing Research institute Co. Ltd.Beijing 102200China

Electromagnetic stirring is one of the widely applied techniques to modify the quality of casting *** from conventional rotate stirring,the helical stirring is more professional in assisting multi-dimensional flow of molten metal and eliminating solidification *** this study,the single-winding helical stirring(SWHS)was introduced,offering advantages such as smaller volume and lower electromagnetic shielding compared to traditional helical stirring *** a comprehensive numerical simulation,the stirring parameters of SWHS were adjusted to yoke inclination angle of 43°and frequency of 12 *** higher electromagnetic force and flow velocity in drawing direction,as well as the lower temperature gradient induced by the SWHS,are positive factors for homogeneous solidification of *** experimental results on Al-8%Si alloy and 0.4%C-1.1%Mn steel demonstrate that compared to rotate stirring,the SWHS process can induce better billet quality and is more effective in accelerating the equiaxed expansion and reducing element *** SWHS process can enhance the equiaxed ratio of the billet by 58.3%and reduce segregation degree of carbon element by 10.97%.Consequently,SWHS holds great promise as a potential approach for improving the quality of continuous casting billets.

关键词： billet electromagnetic stirring helical solidification element segregation numerical simulation

The Enhanced Period Map and Equivariant Deformation Quantizations of Nilpotent Orbits

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Acta Mathematica Sinica,English Series 2024年第3期40卷 885-934页

作者： Shi Lin yu Department of Mathematics School of Mathematical SciencesXiamen UniversityXiamen 361005P.R.China

in a previous paper,the author and his collaborator studied the problem of lifting Hamil-tonian group actions on symplectic varieties and Lagrangian subvarieties to their graded deformation quantizations and apply the general results to coadjoint orbit method for semisimple Lie *** even quantizations were considered *** this paper,these results are generalized to the case of general quantizations with arbitrary *** key step is to introduce an enhanced version of the(truncated)period map defined by Bezrukavnikov and Kaledin for quantizations of any smooth sym-plectic variety X,with values in the space of Picard Lie algebroid over *** an application,we study quantizations of nilpotent orbits of real semisimple groups satisfying certain codimension condition.

关键词： Coadjoint orbit method deformation quantization Harish-Chandra modules semisimple Liegroups

Numerical investigations of the interactions between bubble induced shock waves and particle based on OpenFOAM

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Journal of Hydrodynamics 2024年第2期36卷 355-362页

作者： Jia-xin yu Jin-sen Hu yu-hang Liu Yi-fan Liu Dan Gao yu-ning Zhang Key Laboratory of Power Station Energy Transfer Conversion and System Ministry of EducationSchool of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

The presence of particles and the shock waves generated by the cavitation bubbles can significantly affect the safety and the performance of hydrodynamic *** the present paper,the shock waves generated by cavitation bubble collapsing near the particle are numerically investigated based on the OpenFOAM together with the numerical schlieren for the shock wave *** numerical results reveal that the stand-off distance is one of the paramount factors affecting the interactions between the particle and the shock *** different kinds of shock waves(e.g.,bubble-inception,jet formation,particle reflected and jet-split shock waves)are observed during the bubble collapsing near the *** stand-off distance smaller than 0.5 or larger than 1.1,the maximum pressure at particle surface generated by the bubble growth can surpass those of the collapse stage.

关键词： Particle-bubble interaction shockwaves jetdynamics

Evolution of Biofilm and its Effect on Microstructure of Mortar Surfaces in Simulated Seawater

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 234-243页

作者：荣辉 yu Chenglong 张颖 School of Materials Science and Engineering Tianjin Chengjian UniversityTianjin 300384China Tianjin Key Laboratory of Building Green Functional Materials Tianjin Chengjian UniversityTianjin 300384China

To explore the role of biofilm formation on the corrosion of marine concrete structures, we investigated the attachment of biofilm on mortar surfaces in simulated seawater and the influence of biofilm on the microstructure of mortar surfaces. The results show that the evolution of biofilm on mortar surfaces in simulated seawater is closely related to the corrosion suffered by the mortar, and the process of biofilm attachment and shedding is continuous and cyclical. it is found that the specimens in the absence of biofilm attachment are more severely eroded internally by the corrosive medium in simulated seawater than those in the presence of biofilm attachment. For the specimens without biofilm attachment, after 60 days, gypsum forms,and after 120 days, the number of pores in the mortar is reduced. in contrast, for the specimens in the presence of biofilm attachment, gypsum could only be detected after 90 days, and fewer pores are filled. Therefore, the formation of biofilm could delay the invasion of the corrosive medium into the interior of mortar during the evolution of biofilm on mortar surfaces, mitigating the corrosion of mortars in seawater.

关键词： biofilm attachment mortar sulfur-oxidizing bacteria gypsum simulated seawater microstructure

Current status and trends in small nucleic acid drug development:Leading the future

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Acta Pharmaceutica Sinica B 2024年第9期14卷 3802-3817页

作者： yuxi Miao Chen Fu Zhaojin yu Lifeng yu yu Tang Minjie Wei Department of Pharmacology School of PharmacyChina Medical UniversityShenyang 110122China Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation China Medical UniversityShenyang 110122China Liaoning Medical Diagnosis and Treatment Center Shenyang 110000China Department of Oncology Cancer Hospital of China Medical UniversityLiaoning Cancer Hospital and InstituteShenyang 110042China

Small nucleic acid drugs,composed of nucleotides,represent a novel class of pharmaceuticals that differ significantly from conventional small molecule and antibody-based *** agents function by selectively targeting specific genes or their corresponding messenger RNAs(mRNAs),further modulating gene expression and regulating translation-related *** examples within this category include antisense oligonucleotides(ASO),small interfering RNAs(siRNAs),micro-RNAs(miRNAs),and *** emergence of small nucleic acid drugs as a focal point in contemporary biopharmaceutical research is attributed to their remarkable specificity,facile design,abbreviated development cycles,expansive target spectrum,and prolonged *** challenges such as poor stability,immunogenicity,and permeability issues have been addressed through the integration of chemical modifications and the development of drug delivery *** review provides an overview of the current status and prospective trends in small nucleic acid drug *** with a historical context,we introduce the primary classifications and mechanisms of small nucleic acid ***,we delve into the advantages of the *** and Drug Administration(FDA)approved drugs and mainly discuss the challenges encountered during their *** from researching chemical modification and delivery system that efficiently deliver and enrich small nucleic acid drugs to target tissues,promoting endosomal escape is a critical scientific question and important research direction in siRNA drug *** directions in this field will prioritize addressing these challenges to facilitate the clinical transformation of small nucleic acid drugs.

关键词： Small nucleic acid drugs Oligonucleotide drugs siRNA ASO miRNA Aptamer RNAi Drug development

Mobility and dynamic erosion process of granular flow:insights from numerical investigation using material point method

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Journal of Mountain Science 2024年第8期21卷 2713-2738页

作者： yu Fangwei SU Lijun Li Xinpo ZHAO yu institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610299China University of Chinese Academy of Sciences Beijing 100049China China-Pakistan Joint Research Center on Earth Sciences Islamabad 45320Pakistan Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China College of Civil Engineering and Architecture Zhejiang UniversityHangzhou 310058China MOE Key Laboratory of Soft Soil and Geoenvironmental Engineering Zhejiang UniversityHangzhou 310058China

in order to understand the dynamics of granular flow on an erodible base soil,in this paper,a series of material point method-based granular column collapse tests were conducted to investigate numerically the mobility and dynamic erosion process of granular flow subjected to the complex settings,i.e.,the aspect ratio,granular mass,friction and dilatancy resistance,gravity and presence of water.A set of power scaling laws were proposed to describe the final deposit characteristics of granular flow by the relations of the normalized run-out distance and the normalized final height of granular flow against the aspect ratio,being greatly affected by the complex geological settings,e.g.,granular mass,the friction and dilatancy resistance of granular soil,and presence of water in granular *** index of the coefficient of friction of granular soil was defined as a ratio of the target coefficient of friction over the initial coefficient of friction to quantify the scaling extent of friction change(i.e.,friction strengthening or weakening).There is a characteristic aspect ratio of granular column corresponding to the maximum mobility of granular flow with the minimum index of the apparent coefficient of *** index of the repose coefficient of friction of granular flow decreased gradually with the increase in aspect ratio because higher potential energy of granular column at a larger aspect ratio causes a larger kinetic energy of granular soil to weaken the friction of granular soil as a kind of velocity-related friction *** increase in granular mass reduces gradually the indexes of the apparent and repose coefficients of friction of granular soil to enhance the mobility of granular *** mobility of granular flow increases gradually with the decrease in friction angle or increase in dilatancy angle of granular ***,the increase of gravity accelerates granular flow but showing the same final deposit profile without any dependence on ***

关键词： Column collapse Granular flow Granular soil Material point method Mobility Numerical tests

Effect of Cr_(2)O_(3) on properties of CaO-SiO_(2)-Fe_(t)O-MgO system and dissolution behavior of lime

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Journal of iron and Steel Research international 2024年第4期31卷 870-881页

作者： Shan-nan Li Jian-li Li.yue yu Hang-yu Zhu The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Hubei Provincial Key Laboratory for New Processes of ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The productivity of the chrome-containing semi-steel converter smelting process is directly affected by the slag-forming speed during the converter preliminary *** effects of Cr_(2)O_(3) content on the physicochemical properties of the CaO-SiO_(2)-Fe_(t)O-MgO system,such as melting temperature,solidification behavior,mineral composition,and lime dissolution rate,were *** results showed that the slag was an amorphous phase at 1500℃.When Cr_(2)O_(3) was added,Ca(Fe,Mg)Si_(2)O_(6) and spinel were formed in the *** the increase in Cr_(2)O_(3) content,the amount of spinel precipitation increased,and the dendritic FegO_(4) crystal gradually changed into the granular(Fe,Mg)(Fe,Cr)2O_(4) *** the Cr_(2)O_(3) content increased from O to 2.91 wt.%,the melting temperature of the slag rose,and the melting range of the slag expanded slightly,but the lime dissolution rate did not *** the Cr_(2)O_(3) content further increased to 9.09 wt.%,the melting temperature continued to rise,the melting range rapidly expanded,and the lime dissolution rate decreased.

关键词： Cr_(2)O_(3) Vanadium-titanium magnetite Converter Slag Lime dissolution

Single-atom catalysts for neutral zinc-air batteries

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Science China Materials 2024年第5期67卷 1674-1675页

作者： Jiaxu Zhang Minghao yu Faculty of Chemistry and Food Chemistry&Center for Advancing Electronics Dresden(CfAED) Technische Universität DresdenDresden01062Germany

The escalating global energy demand underscores the urgency of developing sustainable battery ***-air batteries(ZABs)have emerged as promising candidates due to their costeffectiveness,safety,and high energy density[1-4].Conventional ZABs typically rely on a four-electron(4e-)oxygen reduction reaction(ORR)in strongly alkaline electrolytes.

关键词： battery neutral typically

immersive visualization of 3D subsurface ground model developed from sparse boreholes using virtual reality(VR)

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Underground Space 2024年第4期17卷 188-206页

作者： Borui Lyu yu Wang Department of Architecture and Civil Engineering City University of Hong KongKowloon 999077Hong KongChina

Analytics and visualization of multi-dimensional and complex geo-data,such as three-dimensional(3D)subsurface ground models,is critical for development of underground space and design and construction of underground structures(e.g.,tunnels,dams,and slopes)in engineering *** complicated 3D subsurface ground models now can be developed from site investigation data(e.g.,boreholes)which is often sparse in practice,it remains a great challenge to visualize a 3D subsurface ground model with sophisticated stratigraphic variations by conventional two-dimensional(2D)geological *** reality(VR)technology,which has an attractive capability of constructing a virtual environment that links to the physical world,has been rapidly developed and applied to visualization in various disciplines *** on the rapid development of VR,this study proposes a framework for immersive visualization of 3D subsurface ground models in geo-applications using VR *** 3D subsurface model is first developed from limited borehole data in a data-driven ***,a VR system is developed using related software and hardware devices currently available in the markets for immersive visualization and interaction with the developed 3D subsurface ground *** results demonstrate that VR visualization of the 3D subsurface ground model in an immersive environment has great potential in revolutionizing the geo-practices from 2D cross-sections to a 3D immersive virtual environment in digital era,particularly for the emerging digital twins.

关键词： immersive visualization 3D subsurface model Virtual reality Virtual environment interaction