检索结果-南通市图书馆

The Disintegration of a Floating Ferrofluid Layer into an Ordered Drop System in a Vertical Magnetic Field

在线全文

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2024年第10期20卷 2205-2218页

作者： Christina Khokhryakova Konstantin Kostarev Irina Mizeva Laboratory of dispersed System Dynamics Institute of Continuous Media Mechanics UrB RASPerm614018Russia Laboratory of Hydrodynamical Stability Institute of Continuous Media Mechanics UrB RASPerm614018Russia Laboratory of Turbulence Institute of Continuous Media Mechanics UrB RASPerm614018Russia

Magnetic fluids,also known as ferrofluids,are versatile functional materials with a wide range of *** applications span from industrial uses such as vacuum seals,actuators,and acoustic devices to medical uses,including serving as contrast agents for magnetic resonance imaging(MRI),delivering medications to specific locations within the body,and magnetic hyperthermia for cancer *** use of a non-wettable immiscible liquid substrate to support a layer of magnetic fluid opens up new possibilities for studying various fluid flows and related instabilities in multi-phase systems with both a free surface and an *** presence of two deformable boundaries within a ferrofluid layer significantly reduces the critical magnetic field strength required to transform the layer into an organized system of drops or polygonal figures evolving according to the intensity,frequency and direction of the considered magnetic *** paper experimentally investigates this problem by assuming a uniform magnetic field perpendicular to the *** specific subject has not been previously explored *** critical magnetic field intensity required to destabilize the ferrofluid layer is determined based on the layer’s thickness and the fluid’s initial magnetic *** is demonstrated that the critical magnetic field strength needed to disrupt the initially continuous ferrofluid layer increases with the layer’s ***,an increase in the ferrofluid’s magnetic susceptibility results in a decrease in the critical magnetic field *** emerging droplet structures are analyzed in terms of the number of drops,their size,and the periodicity of their *** number of droplets formed depends on the initial thickness of the layer,the presence or absence of a stable rupture in the upper layer,and the rate at which the magnetic field strength is increased to the critical value.A characteristic viscous time is proposed

关键词： Ferrofluid liquid substrate normal field instability ordered droplet structure

Interfacial Chain Entanglements Induced Melt Memory Effect in Poly(ε-caprolactone)/Silica Nanocomposites

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

Chinese Journal of Polymer Science 2022年第11期40卷 1451-1465页

作者： Xiang Liu Wen-Zhi Cui Wei Yu Advanced rheology Institute Department of Polymer Science and EngineeringShanghai Key Laboratory of Electrical Insulation and Thermal AgeingState Key Laboratory for Metal Matrix Composite MaterialsShanghai Jiao Tong UniversityShanghai200240China

It is known that the enhanced melt memory effect is strongly correlated with the retarded chain ***,previous studies using differential scanning calorimetry(DSC)showed a weakened or even vanished melt memory in polymer nanocomposites,although adding nanoparticles in polymers often reduces chain *** this work,we added two kinds of silica nanoparticles,O15 and W22 nanoparticles(with low and high surface silanol density,respectively),to poly(ε-caprolactone)(PCL),where the degree of chain entanglements near nanoparticles increases,and chain dynamics is gradually retarded with increasing silica *** strongly aggregated W22 nanoparticles show significant heterogeneous nucleation,while well-dispersed O15 nanoparticles exhibit very weak heterogeneous *** contrast to the restrained self-nucleation effects during the rapid non-isothermal crystallization of two nanocomposites,we found evident melt memory effects during the slow isothermal crystallization in PCL/O15 nanocomposites as indicated by DSC and polarized light microscopy(PLM)*** melt memory becomes stronger with more O15 nanoparticles,but depends non-monotonically on the loadings of W22 *** lifetime of the melt memory effects matches the chain re-entanglement time of the SN melts of nanocomposites,which is consistent with our previous work on PCL miscible *** complicated influence of silica on nucleation and crystal growth is induced by the spatial inhomogeneity of chain entanglements in the silica-filled PCL *** decrease in the entanglement density of the interfacial chains in the SN melts of nanocomposites is conducive to nucleate under slow isothermal crystallization,but the chain mobility is still greatly restrained by the nanoparticles,causing the slow growth rate of spherulites and the difficulty to form nuclei under fast non-isothermal crystallization.

关键词： PCL Silica nanocomposite Self-nucleation crystallization

The Influence of Peroxide on Bubble Stability and Rheological Properties of Biobased Poly(lactic acid)/Natural Rubber Blown Films

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2022年第2期40卷 197-207页

作者： Peerapong Chanthot Noppadon Kerddonfag Cattaleeya Pattamaprom Research Unit in Polymer rheology and Processing Department of Chemical EngineeringFaculty of EngineeringThammasat UniversityPathum Thani 12120Thailand National Metal and Materials Technology Center National Science and Technology Development AgencyThailand Science ParkPathum Thani 12120Thailand

This study investigated the effects of natural rubber(NR)and an organic peroxide on the rheological properties,mechanical properties,morphology,and bubble stability during film blowing of poly(lactic acid)(PLA).The NR and peroxide contents were varied from 0 wt%to 25 wt%and 0 wt%to 0.5 wt%,*** results confirmed that the presence of well-dispersed NR could significantly improve the toughness,elongation at break,and processability of PLA films,where the optimal amount of NR was 15 wt%.For the reactive blending with peroxide,a suitable peroxide content for good film toughness and clarity was 0.03 wt%,while the higher content of 0.1 wt%could provide slightly higher *** contents are considered much lower than that in the PLA system(without NR),which required up to 0.5 wt%*** rheological studies indicated that the melt strength,the storage modulus(G’)and complex viscosity(η*)at low frequency could be correlated with good film blowing processability of the PLA/NR films at low gel *** parameters failed to correlate in the films having high gel contents as the deformation rate experienced by each test was different leading to the different levels of response to the type and amount of gels.

关键词： Poly(lactic acid) Natural rubber Film blowing stability Peroxide Rheological properties

Droplet Bridging Effect in Polymer/Polymer/Filler Ternary Composites

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第12期42卷 1966-1975,I0010页

作者： Feng-Yi Hou Li Peng Fei Yu Xian-Bo Huang Wei Yu Advanced rheology Institute Department of Polymer Science and EngineeringShanghai Jiao Tong UniversityShanghai200240China National Certified Enterprise Technology Center Kingfa Science and Technology Co.Ltd.Guangzhou510663China DPI P.O.Box 9025600 AXEindhovenThe Netherlands

In particle-filled polymer composites with selective distributions of fillers in one phase,much attention has been focused on the“volume exclusion effect”in reducing the percolation threshold of filler,while the role of dispersed polymer phase acting as bridges of fillers in the particle network has largely been ***,we studied industrially important ternary composites,polypropylene(PP)/ethylene-octene copolymer(a polyolefin elastomer,POE)/talc systems,and adopted rheology to reveal the bridging behavior of POE droplets in the network of talc *** is found that talc fillers concentrate in the PP phase using the“blend first”protocol,while more talc particles are located at the interface of PP and POE phases using the“filler first”*** the POE viscosity and talc size can affect the migration of talc from the POE phase to the PP phase in the“filler first”*** linear rheology behavior indicates that besides the“volume exclusion effect”,the talc-POE hybrid network can further contribute to the reinforcement ***,the POE droplet bridging structure can facilitate the rebuilding of the hybrid network after large amplitude oscillatory shear,in contrast to the un-recoverable structures in the PP/talc binary *** correlation between rheology and selective distribution of fillers in ternary composites may provide practical guidance for processing and designing advanced polymer composites with controlled selective location of fillers.

关键词： Polypropylene Filler selective localization rheology Bridging

Synthesis of waterborne polyurethane using snow as dispersant:Structures and properties controlled by polyols utilization

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2019年第7期35卷 1491-1498页

作者： Changqing Fang Shaofei Pan Zhen Wang Xing Zhou Wanqing Lei Youliang Cheng Faculty of Printing Packaging Engineering and Digital Media TechnologyXi'an University of TechnologyXi'an710048China School of Mechanical and Precision Instrument Engineering Xi'an University of TechnologyXi'an710048China

waterborne polyurethane (WPU) dispersions have gained attention towards environm entally-friendly synthesis. In this article, a series of waterborne polyurethane em ulsions was successfully synthesized and extensively characterized in terms of thermal, mechanical properties, hydrophilic behavior and morphology. Snowwas chosen as dispersant instead of comm only used water. Preparation param eters such as intrinsic properties and molecular weight of polyols were discussed systematically. A chain structure was confirmed by Fourier transform infrared (FT-IR) spectroscopy. when com paring the nature of the polyols (PPG, PEG and PNA, 2000g/mol) of this study, as-synthesized polyether waterborne polyurethane provided higher solid content, viscosity and water-resistance. However, polyester waterborne polyurethane perform ed differently and it exhibited higher therm al stability and crystallinity. When com paring the samples (WPU-N210, WPU-N220, WPU-N230 and WPU-N240) with different molecular weight of the same polyol (PPG) used as soft segment, the emulsion WPU-N220 with molecular weight of 2000g/mol PPG provided the highest solid content and lowest viscosity. It was observed th at particle size was uniform and highly dispersed for all sam ples from TEM images. Therm ogravim etric, differential scanning calorim etry (DSC) and X-ray diffraction results dem onstrated that the emulsion WPU-N230 with m olecular weight of 3000 g/mol PPG possessed higher therm al stability and crystallinity than the other samples. The reason was that the Tg and thermal stability were increased with increasing molecular weight. when molecular weight increased, the arrangem ent of soft segm ent became more regular and so did the regularity of the molecular chains. This work demonstrated that different polyols as soft segment applied could lead to great differences in the structure and property of the resulting WPU.

关键词： Waterborne polyurethane (WPU) Snow Soft segment Polyester Polyether

Factors That Influence Healthcare Professionals’ Online Interaction in a Virtual Community of Practice

在线全文

学校读者我要写书评

暂无评论

Social Networking 2013年第4期2卷 174-184页

作者： Faith Ikioda Sally Kendall Fiona Brooks Anna De Liddo Simon Buckingham Shum Centre for Research in Primary and Community Care University of Hertfordshire Hatfield UK Knowledge media Institute Open University Milton Keynes UK

Online technologies have facilitated the development of Virtual Communities of Practice (virtual CoPs) to support health professionals collaborate online to share knowledge, improve performance and support the spread of innovation and best practices. Research, however,shows that many virtual CoPs do not achieve their expected potential because online interaction among healthcare professionals is generally low. Focusing on health visitors, who are UK qualified midwives or nurses who have undertaken additional qualifications as specialist public health workers in the community, the paper examines the factors that influence online interaction among health visitors collaborating to share knowledge and experience in a virtual CoP. The paper makes suggestions for how to improve online interaction among health professionals in virtual CoPs by increasing the size of membership in order to take advantage of both posting and viewing contributions, facilitating moderation to improve networking among geographically dispersed members groups and im-proving the topic relevance in order to stimulate contributions.

关键词： Virtual Community of Practice Health Visitors Online Interaction Collaboration

A controllable soft-templating approach to synthesize mesoporous carbon microspheres derived from d-xylose via hydrothermal method

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

Journal of Materials Science & Technology 2020年第3期38卷 183-188页

作者： Jian Su Changqing Fang Mannan Yang Youliang Cheng Zhen Wang Zhigang Huang Caiyin You School of Materials Science and Engineering Xi’an University of TechnologyXi’an710048China Faculty of Printing Packaging Engineering and Digital Media TechnologyXi’an University of TechnologyXi’an710048China School of Mechanical and Precision Instrument Engineering Xi’an University of TechnologyXi’an710048China Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics Beijing Technology and Business UniversityBeijing100048China

Highly dispersed carbon microspheres(CMSs)derived from D-xylose were successfully synthesized under hydrothermal conditions and followed by further carbonization,in which F127 was used as a soft ***-synthesized products were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),flourier transform infrared spectroscopy(FT-IR),thermal gravimetric(TG)and X-ray diffraction(XRD).The results showed that the morphology and structure of the CMSs prominently depended on the stirring speed during hydrothermal *** resultant CMSs principally had non-porous structure without stirring and had a very smooth *** the stirring speed increased to 200 rpm,the synthesized mesoporous carbon microspheres at 220?C for 24 h(CMSs-5)had a uniform size distribution of 1–1.4μm and a specific surface area of 452 m^2/***,with further increasing to 400 rpm,as-fabricated carbon products were mostly amorphous with a low degree of *** demonstrated that the diameter of the products decreased with the increase of stirring ***,the sphericity product yield of CMSs reduced with the increase of stirring *** result showed that all the obtained samples contained partial graphite *** addition,a formation mechanism was proposed that involved polymerization product as the precursors for microsphere *** controllable and green strategy may provide a great convenience to study properties and applications of carbon microspheres.

关键词： d-xylose Mesoporous carbon microsphere Soft template Hydrothermal method Stirring

In-situ construction of abundant active centers on hierarchically porous carbon electrode toward high-performance phosphate electrosorption: Synergistic effect of electric field and capture sites

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2024年第1期9卷 126-137页

作者： Peng Zhang Fukuan Li Mingming He Silu Huo Xueli Zhang Benqiang Cen Dezhi Fang Kexun Li Hao Wang College of Environmental Science and Engineering Nankai UniversityTianjin300350China MOE Key Laboratory of Pollution Processes and Environmental Criteria Tianjin Key Laboratory of Environmental Remediation and Pollution ControlTianjin Key Laboratory of Environmental Technology for Complex Trans-Media PollutionNankai UniversityTianjin300350China State Key Laboratory of Simulation and Regulation of Water Cycles in River Basins China Institute of Water Resources and Hydropower ResearchBeijing100038China

Phosphate removal is crucial for eutrophication control and water quality ***-assisted adsorption,an eco-friendly elec-trosorption process,exhibited a promising potential for wastewater ***,there are few works focused on phosphate electro-sorption,and reported electrodes cannot attach satisfactory removal capacities and ***,electro-assisted adsorption of phosphate via in-situ construction of La active centers on hierarchically porous carbon(LaPC)has been originally *** resulted LaPC composite not only possessed a hierarchically porous structure with uniformly dispersed La active sites,but also provided good conductivity for interfacial electron *** LaPC electrode achieved an ultrahigh phosphate electrosorption capability of 462.01 mg g^(-1) at 1 V,outperforming most existing *** superior phosphate removal performance originates from abundant active centers formed by the coupling of electricﬁeld and capture ***,the stability and selectivity toward phosphate capture were maintained well even under comprehensive ***,a series of kinetics and isotherms models were employed to validate the electrosorption *** work demonstrates a deep understanding and promotes a new level of phosphate electrosorption.

关键词： Electro-assisted adsorption Electrosorption Phosphate removal Active centers MOF-derived carbon

Experimental investigation of Daqing Oilfield mudstone's creep characteristic under different water contents

在线全文

学校读者我要写书评

暂无评论

Experimental investigation of Daqing Oilfield mudstone's cre...