检索结果-南通市图书馆

同方期刊数据库

Arsenic and sulfur nanoparticle synthesis mimicking environmental conditions of submarine shallow-water hydrothermal vents

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2022年第1期34卷 301-312页

作者： Vicente Durán-Toro Kurosch Rezwan Solveig I.Bühring Michael Maas MARUM–Center for Marine Environmental Sciences University of BremenBremen 28359Germany Advanced Ceramics University of BremenBremen 28359Germany MAPEX-Center for Materials and Processes University of BremenBremen 28359Germany

Arsenic and sulfur mineralization is a natural phenomenon occurring in hydrothermal systems where parameters like temperature and organic matter(OM)can influence the mobilization of the toxic metalloid in marine *** the present study we analyze the influence of temperature and OM(particularly sulfur-containing additives)on As and S precipitation based on the recent discovery of As-rich nanoparticles in the hydrothermal system near the coast of the greek island *** this end,we experimentally recreate the formation of amorphous colloidal particles rich in As and S via acidification(pH 3–4)of aqueous precursors at various *** higher temperatures,we observe the formation of monodisperse particles within the first 24 h of the experiment,generating colloidal particles with diameters close to 160 *** S:As ratio and particle size of the synthetized particles closely correlates with values for As_(x)S_(y)particles detected in the hydrothermal system off ***,organic sulfur containing additives(cysteine and glutathione,gSH)are a key factor in the process of nucleation and growth of amorphous colloidal As_(x)S_(y)particles and,together with the temperature gradient present in shallow hydrothermal vents,dictate the stabilization of As-bearing nanomaterials in the *** on these findings,we present a simple model that summarizes our new insights into the formation and mobility of colloidal As in aquatic *** this context,amorphous As_(x)S_(y)particles can present harmful effects to micro-and macro-biota not foreseen in bulk As material.

关键词： Biomineralization Milos Hydrothermal vent Arsenic Sulfur Nanoparticles Ecotoxicology

Dynamic modeling of a three-dimensional braided composite thin plate considering braiding directions

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 123-138页

作者： Chentong gAO Huiyu SUN Jianping gU w.M.HUANg College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics School of Mechanical and Aerospace Engineering Nanyang Technological University Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology School of Materials Science and EngineeringNanjing Institute of Technology

Currently, there are a limited number of dynamic models available for braided composite plates with large overall motions, despite the incorporation of three-dimensional(3D) braided composites into rotating blade components. In this paper, a dynamic model of 3D 4-directional braided composite thin plates considering braiding directions is established. Based on Kirchhoff's plate assumptions, the displacement variables of the plate are expressed. By incorporating the braiding directions into the constitutive equation of the braided composites, the dynamic model of the plate considering braiding directions is obtained. The effects of the speeds, braiding directions, and braided angles on the responses of the plate with fixed-axis rotation and translational motion, respectively, are investigated. This paper presents a dynamic theory for calculating the deformation of 3D braided composite structures undergoing both translational and rotational motions. It also provides a simulation method for investigating the dynamic behavior of non-isotropic material plates in various applications.

关键词： three-dimensional (3D) braided composite braiding direction composite thin plate large overall motion dynamic model O313.7

Human induced pluripotent stem cell-derived therapies for regeneration after central nervous system injury

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第11期20卷 3063-3075页

作者： Stephen Vidman Yee Hang Ethan Ma Nolan Fullenkamp giles w.Plant Department of Neuroscience Ohio State UniversityColumbusOHUSA

In recent years,the progression of stem cell therapies has shown great promise in advancing the nascent field of regenerative *** the non-regenerative nature of the mature central nervous system,the concept that“blank”cells could be reprogrammed and functionally integrated into host neural networks remained *** work has also demonstrated the ability of such cells to stimulate intrinsic growth programs in post-mitotic cells,such as *** embryonic stem cells demonstrated great potential in treating central nervous system pathologies,ethical and technical concerns *** barriers,along with the clear necessity for this type of treatment,ultimately prompted the advent of induced pluripotent stem *** advantage of pluripotent cells in central nervous system regeneration is multifaceted,permitting differentiation into neural stem cells,neural progenitor cells,glia,and various neuronal *** precise spatiotemporal application of extrinsic growth factors in vitro,in addition to microenvironmental signaling in vivo,influences the efficiency of this directed *** the pluri-or multipotency of these cells is appealing,it also poses the risk of unregulated differentiation and teratoma *** of the neuroectodermal lineage,such as neuronal subpopulations and glia,have been explored with varying degrees of *** the risk of cancer or teratoma formation is greatly reduced,each subpopulation varies in effectiveness and is influenced by a myriad of factors,such as the timing of the transplant,pathology type,and the ratio of accompanying progenitor ***,successful transplantation requires innovative approaches to develop delivery vectors that can mitigate cell death and support ***,host immune responses to allogeneic grafts must be thoroughly characterized and further developed to reduce the need for *** to a clinical setting wi

关键词： axon regeneration central nervous system regeneration induced pluripotent stem cells neurotrauma regenerative medicine spinal cord injury stem cell therapy

Effect of Equal Channel Angular Extrusion on the Microstructures and Properties of Two Extruded Al-Mg-Si Alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2005年第5期21卷 623-629页

作者： g.w.Lorimer School of Materials The University of ManchesterGrosvenor StreetMl 7HS ManchesterUK

The effect of equal channel angular extrusion （ECAE） on the microstructure of two Al-Mg-Si extrusion alloys was investigated by high resolution electron backscattered diffraction （EBSD） using a field emission gun scanning electron microscope （FEg-SEM） and a transmission electron microscope （TEM）. Two contrasting alloys： a dilute alloy, based on alloy 6061 and a concentrated alloy, based on alloy 6069 were employed for this research. It has been found that prior ECAE to extrusion promotes high angle grain boundaries （HAgBs） in the extrusions, and the increase in HAgBs ratio is due to the large shear deformation involved in the process of ECAE. Tensile testing results show that a further ageing treatment strengthens the alloys after extrusion and the ECAE processed extrusions are more ductile than conventional extrusions.

关键词： Equal channel angular extrusion Electron backscattered diffraction Al-Mg-Si alloys

An abrupt cooling event early in the last interglacial in the northern South China Sea

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2001年第10期44卷 865-870页

作者：涂霞郑范王吉良蔡慧梅汪品先 C.Bühring M.Sarnthein 1. The South China Sea Institute of Oceanology Chinese Academy of Sciences 510301 Guangzhou China 2. Key Laboratory of Marine geology Ministry of Education Tongji University 200092 Shanghai China 3. Institut für geowissenschaften Universit?t Kiel Germany

The high-resolution quantitative analysis of the planktonic foraminifera and the δ18O records of the section between 96.49– 137.6 mcd at ODP Site 1144 on the continental slope of northern South China Sea reveals an abrupt cooling event of sea surface temperature (SST) during the last interglacial (MIS 5.5, i.e. 5e). The dropping range of the winter SST may come to 7.5°C corresponding to 1.2‰ of the δ18O value of sea surface water. This event is comparable with those discovered in the west Europe and the northern Atlantic Ocean, but expressed in a more intensive way. It is inferred that this event may have been induced by middle- to low-latitude processes rather than by polar ice sheet change. Since the Kuroshio-index speciesPulleniatina obliquiloculata displayed the most distinct change at the event, it may also be related to the paleoceanographic change of the low-latitude area in the western Pacific Ocean. This event can be considered as one of “Younger Dryas-style coolings” and is indicative of climate variability of the last interglacial stage.

关键词： northern South China Sea last interglacial period sudden cooling event MIS 5.5 climate variability

Delamination Testing of AlSi10Mg Sandwich Structures with Pyramidal Lattice Truss Core made by Laser Powder Bed Fusion

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2021年第6期34卷 51-62页

作者： M.Nuño J.Bühring M.N.Rao K.-U.Schröder Institute of Structural Mechanics and Lightweight Design RWTH Aachen UniversityWüllnerstraβe 752072 AachenGermany

Sandwich structures possess a high bending stiffness compared to monolithic structures with a similar *** makes them very suitable for lightweight applications,where high stiffness to weight ratios are *** common manufacturing methods of sandwich structures involve adhesive bonding of the core material with the ***,adhesive bonding is prone to delamination,a failure mode that is often difficult to *** paper presents the results of delamination testing of fully additive manufactured(AM)AlSi10Mg sandwich structures with pyramidal lattice truss core using Laser Powder Bed Fusion(LPBF).The faces and struts are 0.5 mm thick,while the core is 2 mm *** inclination of the struts is 45°.To characterise the bonding strength,climbing drum peel tests and out-of-plane tensile tests are *** formulas are derived to predict the expected failure loads and *** analytics and tests are supported by finite element(FE)*** the analytic approach,design guidelines to avoid delamination in AM sandwich structures are *** study presents a critical face sheet thickness to strut diameter ratio for which the structure can *** ratio is mainly influenced by the inclination of the *** peel tests resulted in face yielding,which can also be inferred from the analytics and *** out-of-plane tensile tests didn’t damage the structure.

关键词： Additive Manufacturing Sandwich Structures Pyramidal Lattice Core

Xiamen after 20 Years of Ecological Transformation

在线全文

学校读者我要写书评

暂无评论

China Today 2025年第1期74卷 66-68页

作者： ZACHARY g.LUNDQUIST 不详

The efforts Xiamen has made in ecological protection over the last 20 years have helped it become a beautiful and clean *** years ago,I had the opportunity to travel to the city of Xiamen in southeastern China’s Fujian ***,due to the fact that I was in a rush,I did not have the chance to see the whole *** memory of Xiamen was its pleasant climate and unforgettable beauty-I knew if I ever got the opportunity,I would revisit this *** years went by until I was able to return to this city *** emerging from the airport,I realized that I had grown older,while Xiamen was becoming increasingly youthful and *** exactly had given this city such vitality?

关键词： Ecological Xiamen Transformation

Secondary steady-state and time-periodic flows from a basic flow with square array of odd number of vortices

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2023年第3期44卷 447-458页

作者： Zhimin CHEN w.g.PRICE School of Mathematics and Statistics Shenzhen UniversityShenzhen 518060Guangdong ProvinceChina Ship Science University of SouthamptonSouthampton SO171BJU.K.

In a magnetohydrodynamic(MHD)driven fluid cell,a plane non-parallel flow in a square domain satisfying a free-slip boundary condition is *** energy dissipation of the flow is controlled by the viscosity and linear *** latter arises from the influence of the Hartmann bottom boundary layer in a three-dimensional(3D)MHD experiment in a square bottomed *** basic flow in this fluid system is a square eddy flow exhibiting a network of N~2 vortices rotating alternately in clockwise and anticlockwise *** N is odd,the instability of the flow.gives rise to secondary steady-state flows and secondary time-periodic flows,exhibiting similar characteristics to those observed when N=*** this reason,this study focuses on the instability of the square eddy flow of nine *** is shown that there exist eight bi-critical values corresponding to the existence of eight neutral eigenfunction ***,there exist non-real neutral eigenfunctions,which produce secondary time-periodic flows exhibiting vortices merging in an oscillatory *** Hopf bifurcation phenomenon has not been observed in earlier investigations.

关键词： two-dimensional(2D)Navier-Stokes equation non-parallel square vortex flow primary bifurcation secondary steady-state flow secondary time-periodic flow

A NUMERICAL METHOD FOR SIMULATINg NONLINEAR FLUID-RIgID STRUCTURE INTERACTION PROBLEMS

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2005年第2期18卷 95-109页

作者： Price w.g. The School of Engineering Sciences Ship ScienceUniversity of SouthamptonSouthampton SO17 1BJEngland

A numerical method for simulating nonlinear fluid-rigid structure interaction problems is developed. The structure is assumed to undergo large rigid body motions and the fluid flow is governed by nonlinear, viscous or non-viscous, field equations with nonlinear boundary conditions applied to the free surface and fluid-solid interaction interfaces. An Arbitrary-LagrangianEulerian (ALE) mesh system is used to construct the numerical model. A multi-block numerical scheme of study is adopted allowing for the relative motion between moving overset grids, which are independent of one another. This provides a convenient method to overcome the difficulties in matching fluid meshes with large solid motions. Nonlinear numerical equations describing nonlinear fluid-solid interaction dynamics are derived through a numerical discretization scheme of study. A coupling iteration process is used to solve these numerical equations. Numerical examples are presented to demonstrate applications of the model developed.

关键词： fluid-structure interaction nonlinear numerical analysis ALE description overset grids flow around bluff-body