检索结果-南通市图书馆

Understanding the Thermal Impedance of Silicone Rubber/Hexagonal Boron Nitride Composites as Thermal Interface materials

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3期42卷 352-363,I0008页

作者： Yuan Ji Shi-Da Han Hong Wu Shao-Yun Guo Feng-Shun Zhang Jian-Hui Qiu The State Key Laboratory of polymer materials engineering Sichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing TechnologyPolymer Research InstituteSichuan UniversityChengdu 610065China Institute of Chemical materials China Academy of Engineering PhysicsMianyang 621900China department of Mechanical engineering Faculty of Systems Science and TechnologyAkita Prefectural UniversityAkita 015-0055Japan

Silicone rubber(SR) composites are most widely used as thermal interface materials(TIMs) for electronics heat dissipation. Thermal impedance as the main bottleneck limiting the performance of TIMs is usually neglected. Herein, the thermal impedance of SR composites loaded with different levels of hexagonal boron nitride(h-BN) as TIMs was elaborated for the first time by the ASTM D 5470 standard test and finite element analysis. It was found that elastic modulus and surface roughness of SR composites increased with the increase of h-BN content, indicating that the conformity was reduced. When the assembly pressure was 0.69 MPa, there existed an optimal h-BN content at which the contact resistance was minimum(0.39 K·cm^(2)·W^(-1)). Although the decreased bond line thickness(BLT) by increasing the assembly pressure was beneficial to reduce the thermal impedance, the proper assembly pressure should be selected to prevent the warpage of the contact surfaces and the increase in contact resistance, according to the compression properties of the SR composites. This study provides valuable insights into fabrication of high-performance TIMs for modern electronic device applications.

关键词： Thermal interface materials Hexagonal boron nitride Thermal impedance Surfaces

Tissue adhesive,ROS scavenging and injectable PRP-based‘plasticine’for promoting cartilage repair

在线全文

学校读者我要写书评

暂无评论

Regenerative Biomaterials 2024年第1期3卷 94-107页

作者： Shiao Li Dawei Niu Haowei Fang Yancheng Chen Jinyan Li Kunxi Zhang Jingbo Yin Peiliang Fu department of Orthopedics Shanghai Changzheng HospitalNaval Medical UniversityShanghai 200003P.R.China department of polymer materials School of Materials Science and EngineeringShanghai UniversityShanghai 200444P.R.China

Platelet-rich plasma(PRP)that has various growth factors has been used clinically in cartilage repair.However,the short residence time and release time at the injury site limit its therapeutic effect.The present study fabricated a granular hydrogel that was assembled from gelatin microspheres and tannic acid through their abundant hydrogen bonding.Gelatin microspheres with the gelatin concentration of 10wt%and the diameter distribution of 1-10 lm were used to assemble by tannic acid to form the granular hydrogel,which exhibited elasticity under low shear strain,but flowability under higher shear strain.The viscosity decreased with the increase in shear rate.Meanwhile,the granular hydrogel exhibited self-healing feature during rheology test.Thus,granular hydrogel carrying PRP not only exhibited well-performed injectability but also performed like a‘plasticine’that possessed good plasticity.The granular hydrogel showed tissue adhesion ability and reactive oxygen species scavenging ability.Granular hydrogel carrying PRP transplanted to full-thickness articular cartilage defects could integrate well with native cartilage,resulting in newly formed cartilage articular fully filled in defects and well-integrated with the native cartilage and subchondral bone.The unique features of the present granular hydrogel,including injectability,plasticity,porous structure,tissue adhesion and reactive oxygen species scavenging provided an ideal PRP carrier toward cartilage tissue engineering.

关键词： cartilage regeneration granular hydrogel gelatin tannic acid PRP

Unraveling magnetic properties and martensitic transformation in Mn-rich Ni-Mn-Sn alloys:first-principles calculations and experiments

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

Rare Metals 2024年第4期43卷 1769-1785页

作者： Yu Zhang Jing Bai Ke-Liang Guo Jia-Xin Xu Jiang-Long Gu Nicola Morley Qui-Zhi Gao Yu-Dong Zhang Claude Esling Xiang Zhao Liang Zuo Key Laboratory for Anisotropy and Texture of materials (Ministry of Education) School of Material Science and EngineeringNortheastern University Key Laboratory of Dielectric and Electrolyte Functional material Hebei Province School of Resources and Materials Northeastern University at Qinhuangdao department of material Science and engineering University of Sheffield State Key Laboratory of Metastable materials Science and Technology Yanshan University Laboratoire d'Etude des Microstructures Et de Mecanique des Materiaux University of Lorraine

We have investigated the phase stability,magnetic properties,and martensitic transformation thermodynamics/kinetics of the Ni24-xMn18+x+ySn6-y（x,y=0,1,2） system by combining the first-principles calculations and experiments.The calculation results show that the optimized lattice parameters are consistent with the experimental data.Respectively,we obtain the relation equation for the austenite formation energy(Eform-A) and Mn content(XMn):Eform-A=507.358XMn-274.126,as well as for the six-layer modulated（6M） martensite formation energy(Eform-6M) and Ni content(XNi):Eform-6M=-728.484XNi+264.374.The ternary phase diagram of the total magnetic moment was established.The excess Mn will reduce the total magnetic moment of 6M（Mag6M） and non-modulated（NM）(MagNM) martensites,with the following equations relating the total magnetic moment and Mn content:Mag6M=-15.905XMn+7.902and MagNM=-14.781XMn+7.411,while the effect on austenite is complex.The variation of total magnetic moment is mainly dominated by the Mn atomic magnetic moment.The 3d electrons of MnSn（Mn at Sn sublattice）play an important role in magnetic properties from the perspective of the electronic density of states.Based on the thermodynamics of martensitic transformation,the alloys will likely undergo austenite?6M?NM transformation sequence.Combining the thermodynamic and kinetic results,the martensitic transformation temperature decreases with x increasing and increases with y increasing.These results are expected to provide reference for predicting the phase stability and magnetic properties of NiMn-Sn alloys.

关键词： Ni–Mn–Sn First-principles calculations Martensitic transformation Magnetic property Kinetics

Recent progress in the development of dielectric elastomer materials and their multilayer actuators

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & engineering) 2024年第3期25卷 183-205页

作者： Shengchao JIANG Junbo PENG Lvting WANG Hanzhi MA Ye SHI ZJU-UIUC Institute Zhejiang UniversityJiaxing 314400China College of Mechanical engineering Zhejiang UniversityHangzhou 310058China department of polymer Science and engineering Zhejiang UniversityHangzhou 310058China

Dielectric elastomers(DEs)have emerged as one of the most promising artificial muscle technologies,due to their exceptional properties such as large actuation strain,fast response,high energy density,and flexible processibility for various configurations.Over the past two decades,researchers have been working on developing DE materials with improved properties and exploring innovative applications of dielectric elastomer actuators(DEAs).This review article focuses on two main topics:recent material innovation of DEs and development of multilayer stacking processes for DEAs,which are important to promoting commercialization of DEs.It begins by explaining the working principle of a DEA.Then,recently developed strategies for preparing new DE materials are introduced,including reducing mechanical stiffness,increasing dielectric permittivity,suppressing viscoelasticity loss,and mitigating electromechanical instability without pre-stretching.In the next section,different multilayer stacking methods for fabricating multilayer DEAs are discussed,including conventional dry stacking,wet stacking,a novel dry stacking method,and micro-fabrication-enabled stacking techniques.This review provides a comprehensive and up-to-date overview of recent developments in high-performance DE materials and multilayer stacking methods.It highlights the progress made in the field and also discusses potential future directions for further advancements.

关键词： Dielectric elastomer actuator(DEA) Dielectric elastomer(DE) material svnthesis Multilaver stacking method

Curing the vulnerable heterointerface via organic-inorganic hybrid hole transporting bilayers for efficient inverted perovskite solar cells

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 Chemical Letters 2024年第6期35卷 254-257页

作者： Kangrong Yan Ziqiu Shen Yanchun Huang Benfang Niu Hongzheng Chen Chang-Zhi Li State Key Laboratory of Silicon and Advanced Semiconductor materials Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

To promote the practices of perovskite photovoltaics,it requires to develop efficient perovskite solar cells(PVSCs)standing long-time operation under the adverse environments.Herein,we demonstrate that the tailor-made conjugated polymers as conductive adhesives stabilized the originally redox-reactive heterointerface between perovskite and metal oxide,facilitating the access of efficient and stable inverted PVSCs.It was revealed that bithiophene and phenyl alternating conjugated polymers with partial glycol chains atop of the metal oxide layer has resulted in effective organic-inorganic hybrid hole transporting bilayers,which allow maintaining efficient hole extraction and transport,meanwhile preventing halide migration to directly contact with the nickel oxide(NiO_(x))layer.As a result,the corresponding inverted PVSCs with the organic-inorganic hole transporting bilayers have achieved an excellent power conversion efficiency of 23.22%,outperforming 20.65% of bare NiO_(x)-based devices.Moreover,the encapsulated PVSCs with organic-inorganic bilayers exhibited the excellent photostability with 91% of the initial efficiency after 1000-h one-sun equivalent illumination in ambient conditions.Overall,this work provides new insights into stabilizing the vulnerable heterointerface for perovskite solar cells.

关键词： Perovskite solar cells Conjugated polymer Hole transporting bilayer Charge extraction Heterointerface degradation

Nickel-based cerium zirconate inorganic complex structures for CO_(2)valorisation via dry reforming of methane

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第6期140卷 12-23页

作者： Juan Luis Martín-Espejo Loukia-Pantzechroula Merkouri Jesús Gándara-Loe José Antonio Odriozola Tomas Ramirez Reina Laura Pastor-Pérez department of Inorganic Chemistry and material Sciences Institute of Seville University of Seville-CSICSeville 41092Spain department of Chemical and Process engineering University of SurreyGuildford GU27XHUnited Kingdom

The increasing anthropogenic emissions of greenhouse gases(GHG)is encouraging extensive research in CO_(2)utilisation.Dry reforming of methane(DRM)depicts a viable strategy to convert both CO_(2)and CH4into syngas,a worthwhile chemical intermediate.Among the different active phases for DRM,the use of nickel as catalyst is economically favourable,but typically deactivates due to sintering and carbon deposition.The stabilisation of Ni at different loadings in cerium zirconate inorganic complex structures is investigated in this work as strategy to develop robust Ni-based DRM catalysts.XRD and TPR-H2analyses confirmed the existence of different phases according to the Ni loading in these materials.Besides,superficial Ni is observed as well as the existence of a CeNiO_(3)perovskite structure.The catalytic activity was tested,proving that 10 wt.%Ni loading is the optimum which maximises conversion.This catalyst was also tested in long-term stability experiments at 600and 800℃in order to study the potential deactivation issues at two different temperatures.At 600℃,carbon formation is the main cause of catalytic deactivation,whereas a robust stability is shown at 800℃,observing no sintering of the active phase evidencing the success of this strategy rendering a new family of economically appealing CO_(2)and biogas mixtures upgrading catalysts.

关键词： CO_(2)conversion Dry reforming of methane Nickel catalysts Pyrochlore Cerium zirconate

Bioinspired anti-freezing 3D-printable conductive hydrogel microfibers for highly-sensitive and wide-range detection of ultralow and high strains

在线全文

学校读者我要写书评

暂无评论

Green Chemical engineering 2024年第1期5卷 132-143页

作者： Yi-Min Yang Ting-Yuan Hu Haidong Fan Lu Shi Shi-Yuan Zhang Zhuang Liu Xiao-Jie Ju Rui Xie Wei Wang Liang-Yin Chu School of Chemical engineering Sichuan UniversityChengdu610065China department of Mechanics Sichuan UniversityChengdu610065China State Key Laboratory of polymer materials engineering Sichuan UniversityChengdu610065China

Soft strain sensors that can transduce stretch stimuli into electrical readouts are promising as sustainable wearable electronics.However,most strain sensors cannot achieve highly-sensitive and wide-range detection of ultralow and high strains.Inspired by bamboo structures,anti-freezing microfibers made of conductive poly(vinyl alcohol)hydrogel with poly(3,4-ethylenedioxythiphene)-poly(styrenesulfonate)are developed via continuous microfluidic spinning.The microfibers provide unique bamboo-like structures with enhanced local stress to improve both their length change and resistance change upon stretching for efficient signal conversion.The microfibers allow highlysensitive(detection limit:0.05%strain)and wide-range(0%-400%strain)detection of ultralow and high strains,as well as features of good stretchability(485%strain)and anti-freezing property(freezing temperature:-41.1°C),fast response(200 ms),and good repeatability.The experimental results,together with theoretical foundation analysis and finite element analysis,prove their enhanced length and resistance changes upon stretching for efficient signal conversion.By integrating microfluidic spinning with 3D-printing technique,the textiles of the microfibers can be flexibly constructed.The microfibers and their 3D-printed textiles enable highperformance monitoring of human motions including finger bending and throat vibrating during phonation.This work provides an efficient and general strategy for developing advanced conductive hydrogel microfibers as highperformance wearable strain sensors.

关键词： Conductive hydrogel microfibers Microfluidics Sensitive detection Wide detection range Anti-freezing

Structural disruption of melanin-like polymers with boosted UV protection

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第5期67卷 1653-1663页

作者： Zhen Yang Xianheng Wang Wanjie Bai Zikun Zou Haoxing Wu Yiwen Li department of Radiology Huaxi MR Research CenterFunctional and Molecular Imaging Key Laboratory of Sichuan ProvinceNational Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityChengdu 610041China College of polymer Science and engineering State Key Laboratory of Polymer Materials EngineeringSichuan UniversityChengdu 610065China

Manipulating the energy structure of materials represents an efficient way to regulate their light absorption behaviors. For example, constructing donor-acceptor(D-A) structures to increase the polarizability and reduce the energy bandgap of local molecules has been widely used in the field of organic photovoltaics with ordered structures. Remarkably, even in disordered and chaotic systems such as melanin-like polydopamine(PDA), visible and near-infrared light absorption can be significantly improved using this strategy. However, there has been a noticeable dearth of research on the ultraviolet(UV) light absorption regulation of bioinspired polymers with disordered and chaotic architectures by tailoring the D-A microstructures. In this study, a series of benzoheterocyclic molecules with strong electron-donating features screened by molecular simulation calculations were involved in disrupting the D-A structures within PDA. The destruction of D-A structures promoted the increase of the energy band gap and finally boosted the UV absorption of PDA. The resulting PDA nanoparticles with enhanced UV absorption were further employed to fabricate UV shielding composite films to protect the growth of plants from harmful UV radiation. This research may open up new avenues for structural disruption of bioinspired polymers for enhanced photoprotection applications.

关键词： melanin-like polymers polydopamine D-A structure UV absorption photoprotection

Fundamentals and progress of the manifold method based on independent covers

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第4期67卷 966-991页

作者： SU HaiDong LIN ShaoZhong XIE ZhiQiang GONG YaQi QI YongFeng material and engineering Structure department Yangtze River Scientific Research InstituteWuhan 430010China Research Center of Water engineering Safety and Disaster Prevention of Ministry of Water Resources Wuhan 430010China

Aiming to solve mesh generation,computational stability,accuracy control,and other problems encountered with existing numerical methods,such as the finite element method and the finite volume method,a new numerical computational method for continuum mechanics,namely the manifold method based on independent covers(MMIC),is proposed based on the concept of mathematical manifolds,to form partitioned series solutions of partial differential equations.As partitions,the cover meshes have the characteristics of arbitrary shape,arbitrary connection,and arbitrary refinement.They are expected to fundamentally solve the mesh generation problem and can also simulate the precise geometric boundaries of the CAD model and strictly impose boundary conditions.In the selection of series solutions,local analytical solutions(such as series solutions at crack tips and series solutions in infinite domains)or proper forms of complete series can be used to reflect the local or global characteristics of the physical field to accelerate convergence.Various applications are presented.A new method of beam,plate,and shell analysis is proposed.The deformation characteristics of beams,plates,and shells are simulated with polynomial series of suitable forms,and the analysis of curved beams and shells with accurate geometric representation is realized.For the static elastic analysis of two-dimensional structures,a mesh splitting algorithm is proposed,and h-p version adaptive analysis is carried out with error estimation.Thus,automatic computation integrated with CAD is attempted.Adaptive analysis is also attempted for the solution of differential equations of fluids.For the one-dimensional convection-diffusion equation and Burgers equation,calculation results with high precision are obtained in strong convection and shock wave simulations,avoiding nonphysical oscillations.And solving the two-dimensional incompressible Navier-Stokes equation is also attempted.The series solution formula is used to obtain the physical quantity of interest of the m

关键词： series solutions mesh generation adaptive analysis fixed meshes numerical manifold method