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MATERIAL MULTIPOLE MECHANICS OF ELASTIC DIELECTRIC COMPOSITES
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作者 周树昂 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1990年第3期215-237,共23页
The overall mechanical and electrical behaviors of elastic dielectric composites are investigated with the aid of the concept of material multipoles. In particular, by introducing a statistical continuum material mult... The overall mechanical and electrical behaviors of elastic dielectric composites are investigated with the aid of the concept of material multipoles. In particular, by introducing a statistical continuum material multipole theory, the effects of the electric-elastic interaction and the microstructure (size, shape, orientation,...) of inhomogeneous particles on the overall behaviors of the composites can be obtained. A basic solution for an ellipsoidal elastic inhomogeneity with electric polarization in an infinite elastic dielectric medium is first given, which shows that classical Eshelby 's elastic solution is modified by the presence of electric-elastic interaction. The overall macroscopic constitutive relations and their overall macroscopic material parameters accounting for electroelastic interaction effect are then derived for the elastic dielectric composites. Some quantitative calculations on the problems with statistical anisotropy, the shape effect and the electric-elastic interaction are finally given for dilute composites. 展开更多
关键词 BODY MATERIAL MULTIPOLE MECHANICS OF ELASTIC dielectric composites
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In silico optimization of actuation performance in dielectric elastomercomposites via integrated finite element modeling and deep learning
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作者 Jiaxuan Ma Sheng Sun 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2024年第1期48-56,共9页
Dielectric elastomers(DEs)require balanced electric actuation performance and mechanical integrity under applied voltages.Incorporating high dielectric particles as fillers provides extensive design space to optimize ... Dielectric elastomers(DEs)require balanced electric actuation performance and mechanical integrity under applied voltages.Incorporating high dielectric particles as fillers provides extensive design space to optimize concentration,morphology,and distribution for improved actuation performance and material modulus.This study presents an integrated framework combining finite element modeling(FEM)and deep learning to optimize the microstructure of DE composites.FEM first calculates actuation performance and the effective modulus across varied filler combinations,with these data used to train a convolutional neural network(CNN).Integrating the CNN into a multi-objective genetic algorithm generates designs with enhanced actuation performance and material modulus compared to the conventional optimization approach based on FEM approach within the same time.This framework harnesses artificial intelligence to navigate vast design possibilities,enabling optimized microstructures for high-performance DE composites. 展开更多
关键词 dielectric elastomer composites Multi-objective optimization Finite element modeling Convolutional neural network
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Co-modulated interface binding energy and electric field distribution of layer-structured PVDF–LDPE dielectric composites with BaTiO3: experiment and multiscale simulations
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作者 Ruitian Bo Chunfeng Wang +2 位作者 Yongliang Wang Peigang He Zhidong Han 《Frontiers of Materials Science》 SCIE CSCD 2023年第3期155-167,共13页
The layer-structured composites were built by the dielectric and insulating layers composed of polyvinylidene fluoride(PVDF)and low-density polyethylene(LDPE)composites containing barium titanate(BT)to modulate the di... The layer-structured composites were built by the dielectric and insulating layers composed of polyvinylidene fluoride(PVDF)and low-density polyethylene(LDPE)composites containing barium titanate(BT)to modulate the dielectric and energy storage properties of the composites.The simulations on the interface models for molecular dynamics and the geometric models for finite element analysis were performed together with the experimental characterization of the morphology,dielectric,and energy storage properties of the composites.The results revealed that polyethylene as an insulating layer played a successful role in modulating dielectric permittivity and breakdown strength while BT particles exerted positive effects in improving the miscibility between the composed layers and redistributing the electric field.The strong interface binding energy and the similar dielectric permittivity between the PVDF layer and the BT20/LDPE layer made for the layer-structured composites with a characteristic breakdown strength(Eb)of 188.9 kV·mm^(−1),a discharge energy density(Ud)of 1.42 J·cm^(−3),and a dielectric loss factor(tanδ)of 0.017,which were increased by 94%,141%,and decreased by 54%in comparison with those of the BT20/PVDF composite,respectively. 展开更多
关键词 dielectric composite layer structure low-density polyethylene polyvinylidene fluoride molecular dynamics simulation finite element analysis
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Ultraviolet‑Irradiated All‑Organic Nanocomposites with Polymer Dots for High‑Temperature Capacitive Energy Storage 被引量:1
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作者 Jiale Ding Yao Zhou +5 位作者 Wenhan Xu Fan Yang Danying Zhao Yunhe Zhang Zhenhua Jiang Qing Wang 《Nano-Micro Letters》 SCIE EI CSCD 2024年第3期398-406,共9页
Polymer dielectrics capable of operating efficiently at high electric fields and elevated temperatures are urgently demanded by next-generation electronics and electrical power systems.While inorganic fillers have bee... Polymer dielectrics capable of operating efficiently at high electric fields and elevated temperatures are urgently demanded by next-generation electronics and electrical power systems.While inorganic fillers have been extensively utilized to improved high-temperature capacitive performance of dielectric polymers,the presence of thermodynamically incompatible organic and inorganic components may lead to concern about the long-term stability and also complicate film processing.Herein,zero-dimensional polymer dots with high electron affinity are introduced into photoactive allyl-containing poly(aryl ether sulfone)to form the all-organic polymer composites for hightemperature capacitive energy storage.Upon ultraviolet irradiation,the crosslinked polymer composites with polymer dots are efficient in suppressing electrical conduction at high electric fields and elevated temperatures,which significantly reduces the high-field energy loss of the composites at 200℃.Accordingly,the ultraviolet-irradiated composite film exhibits a discharged energy density of 4.2 J cm^(−3)at 200℃.Along with outstanding cyclic stability of capacitive performance at 200℃,this work provides a promising class of dielectric materials for robust high-performance all-organic dielectric nanocomposites. 展开更多
关键词 High-temperature energy storage Polymer dots Ultraviolet irradiation All-organic composite dielectrics
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Research on quantum well intermixing of 680 nm AlGaInP/GaInP semiconductor lasers induced by composited Si-Si_(3)N_(4) dielectric layer 被引量:3
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作者 Tianjiang He Suping Liu +4 位作者 Wei Li Cong Xiong Nan Lin Li Zhong Xiaoyu Ma 《Journal of Semiconductors》 EI CAS CSCD 2022年第8期46-52,共7页
The optical catastrophic damage that usually occurs at the cavity surface of semiconductor lasers has become the main bottleneck affecting the improvement of laser output power and long-term reliability.To improve the... The optical catastrophic damage that usually occurs at the cavity surface of semiconductor lasers has become the main bottleneck affecting the improvement of laser output power and long-term reliability.To improve the output power of 680 nm AlGaInP/GaInP quantum well red semiconductor lasers,Si-Si_(3)N_(4)composited dielectric layers are used to induce its quantum wells to be intermixed at the cavity surface to make a non-absorption window.Si with a thickness of 100 nm and Si_(3)N_(4)with a thickness of 100 nm were grown on the surface of the epitaxial wafer by magnetron sputtering and PECVD as diffusion source and driving source,respectively.Compared with traditional Si impurity induced quantum well intermixing,this paper realizes the blue shift of 54.8 nm in the nonabsorbent window region at a lower annealing temperature of 600 ℃ and annealing time of 10 min.Under this annealing condition,the wavelength of the gain luminescence region basically does not shift to short wavelength,and the surface morphology of the whole epitaxial wafer remains fine after annealing.The application of this process condition can reduce the difficulty of production and save cost,which provides an effective method for upcoming fabrication. 展开更多
关键词 high power semiconductor laser rapid thermal annealing composited dielectric layer quantum well intermixing optical catastrophic damage nonabsorbent window
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Simultaneously Improved Dielectric Constant and Breakdown Strength of PVDF-based Composites with Polypyrrole Nanowire Encapsuled Molybdenum Disulfide Nanosheets
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作者 Hua-Bin Luo Xiao-Ren Pan +2 位作者 Jing-Hui Yang Xiao-Dong Qi Yong Wang 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2022年第5期515-525,共11页
High-performance dielectric polymer composites have received increasing attention due to their important applications in the field of energy storage.The rational structural design of hybrid fillers can lead to a balan... High-performance dielectric polymer composites have received increasing attention due to their important applications in the field of energy storage.The rational structural design of hybrid fillers can lead to a balance between high dielectric constant and insulation in composites.In this work,novel hybrid fillers were fabricated by in situ synthesizing one-dimensional polypyrrole nanowires(PPynws)on the twodimensional molybdenum disulfide(MoS_(2)),which integrated the good ion polarization ability of PPynws and the high insulation and adjustable band gap of MoS_(2).Compared with the binary poly(vinylidene fluoride)(PVDF)/MoS_(2) composites,the PVDF/MoS_(2)-PPynws composites exhibited remarkably improved dielectric constant and breakdown strength,while the dielectric loss was still maintained at a low level.An optimal ternary composite with 1 wt%MoS_(2)-PPynws showed a high dielectric constant(15@1kHz),suppressed dielectric loss(0.027@1kHz),and high breakdown strength(422.1 MV/m).PPynws inducing strong interfacial polarization and the highly insulated MoS_(2) nanosheets extending the breakdown path mainly contributed to the synchronously enhanced dielectric constant and breakdown strength.This intriguing synthesis method of PVDF/MoS_(2)-PPynws nanocomposite will open up new opportunities for fabricating nanostructured polymer composites to produce high dielectric materials. 展开更多
关键词 Hybrid fillers Molybdenum disulfide Polypyrrole nanowires dielectric composites Breakdown strength
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Improved dielectric constant and energy density of P(VDF-HFP)composites using NBT-xST(x=0,0.10,0.26)whiskers
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作者 Xuefan Zhou Lu Wang +3 位作者 Guoliang Xue Kechao Zhou Hang Luo Dou Zhangy 《Journal of Advanced Dielectrics》 CAS 2018年第6期80-88,共9页
The high-performance energy-storage dielectric capacitors are increasingly important due to their wide applications in high power electronics.Here,we fabricated a novel P(VDF-HFP)-based capacitor with surface-modified... The high-performance energy-storage dielectric capacitors are increasingly important due to their wide applications in high power electronics.Here,we fabricated a novel P(VDF-HFP)-based capacitor with surface-modified NBT-xST(x?0,0.10,0.26)whiskers,denoted as Dop@NBT-xST/P(VDF-HFP).The influences of ST content,fillers’volume fraction and electric field on the dielectric properties and energy-storage performance of the composites were investigated systematically.The results show that the dielectric constant monotonously increased with the increase of ST content and fillers’volume fraction.The composite containing 10.0 vol%NBT-0.26STwhiskers possessed a dielectric constant of 39 at 1 kHz,which was 5.6 times higher than that of pure P(VDF-HFP).It was noticed that the D-E loops of the composites became thinner and thinner with the increase of ST content.Due to the reduced remnant polarization,the composite with 5.0 vol%NBT-0.26STwhiskers achieved a high energy density of 6.18 J/cm3 and energy efficiency of approximately 57%at a relatively low electric field of 200 kV/mm.This work indicated that NBT-0.26ST whisker is a kind of potential ceramic filler in fabricating the dielectric capacitor with high discharged energy density and energy efficiency. 展开更多
关键词 P(VDF-HFP) NBT-xST whiskers dielectric composite dielectric constant energy storage
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Preparation and Characterization of Multi Shape ZnO/PVDF Composite Materials
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作者 翁凌 JU Peihai +2 位作者 LI Hongxia YAN Liwen LIU Lizhu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2017年第4期958-962,共5页
Two different morphologies of ZnO(lotus-shaped, rod-shaped) and ZnO/PVDF composite materials were prepared. The morphologies of ZnO and composite materials were characterized by scanning electron microscopy(SEM) a... Two different morphologies of ZnO(lotus-shaped, rod-shaped) and ZnO/PVDF composite materials were prepared. The morphologies of ZnO and composite materials were characterized by scanning electron microscopy(SEM) and transmission electron microscopy(TEM). Fourier transform infrared spectroscopy(FT-IR), thermal gravimetry(TG), and X-ray diffraction(XRD) were also used to characterize the chemical structures and phase composites of ZnO and ZnO/PVDF composite materials. Breakdown voltage, dielectric constant and dielectric loss of ZnO/PVDF composite materials were also tested. Microstructure analysis showed that ZnO nanoparticles dispersed uniformly in the matrix. And the dielectric constant expresses a significantly improvement while the dielectric loss and breakdown voltage expresses no significant change. Moreover, dielectric constant keeps an improvement tendency with increasing content of ZnO. 展开更多
关键词 polyvinylidene fluoride(PVDF) zinc oxide(ZnO) composite materials morphology dielectric properties
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Ultrasmall barium titanate nanoparticles modulated stretchable dielectric elastomer sensors with large deformability and high sensitivity
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作者 Zun-Peng Feng Ya-Nan Hao +6 位作者 Jing Qin Shao-Long Zhong Ke Bi Yu Zhao Li-Juan Yin Jia-Yao Pei Zhi-Min Dang 《InfoMat》 SCIE CSCD 2023年第8期94-106,共13页
Large deformability and high sensitivity is difficult to be realized simultaneously in flexible sensors.Herein,taking advantage of the high permittivity and highly active surfaces of the ultrasmall barium titanate nan... Large deformability and high sensitivity is difficult to be realized simultaneously in flexible sensors.Herein,taking advantage of the high permittivity and highly active surfaces of the ultrasmall barium titanate nanoparticles(BT NPs)and the high stretchability of the p(BA-GMA)elastomer matrix,we propose a high-performance soft stretchable sensor.The addition of the ultrasmall BT NPs can not only increase the permittivity and capacitance of polyacrylate-matrix composite dielectric material to obtain a high sensitivity,but also basically maintains the excellent mechanical properties of the polymer matrix.The dielectric constants of the composite films increase from 5.68 to 13.13 at 10 kHz with the increase of BT NPs content from 0 to 15 vol.%,which results in a high capacitance of 236.16 pF for 15 vol.%BT/p(BA-GMA)sensor.Combining the high permittivity and the large deformability(a maximal deformation of 87.2%),the 15 vol.%BT/p(BA-GMA)sensor has high sensitivity and shows high linearity and stable output even if under dynamic measurement.The dual-mode sensor that utilizes the orthogonality of capacitance-resistance is designed,which shows excellent performance in monitoring human body movements and noncontact measurement.The results present that the BT/p(BA-GMA)-based sensor has high stability and reliability not exceed 65C,which can meet the application requirements in dynamic monitoring. 展开更多
关键词 barium titanate composite dielectric ELASTOMER NANOPARTICLES stretchable sensor
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Percolation of carbon nanomaterials for high-k polymer nanocomposites
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作者 Jinkai Yuan 《Chinese Chemical Letters》 SCIE CAS CSCD 2017年第11期2036-2044,共9页
High-k polymer composite materials are next-generation dielectrics that show amazing applications in diverse electrical and electronic devices. Establishing near-percolated network of conducting filler in an insulatin... High-k polymer composite materials are next-generation dielectrics that show amazing applications in diverse electrical and electronic devices. Establishing near-percolated network of conducting filler in an insulating polymer matrix is a promising approach to develop flexible high-k dielectrics. However, challenges still exist today on fine controlling the network morphology to achieve extremely high k values and low losses simultaneously. The relationship between the network morphology and the dielectric properties of polymer composites is raising a number of fundamental questions. Herein, recent progress towards high-k polymer composites based on carbon nanomaterials is reviewed. Particular attention is paid on the influence of the network morphology on the dielectric properties. Some perspectives that warrant further investigation in the future are also addressed. 展开更多
关键词 Percolation Carbon nanomaterials Polymer composites dielectric constant Permittivity
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Structural,Dielectric,and Magnetic Studies on Electrospun Magnesium Ferrite-Polyvinylidene Fluoride Core–Shell Composite Fibers
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作者 V.Revathi S.Dinesh Kumar +3 位作者 P.Chithra Lekha V.Subramanian T.S.Natarajan C.Muthamizhchelvan 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2014年第4期557-562,共6页
The sub-micron(of the order of 150 nm) thick core–shell composite fibers of magnesium ferrite-polyvinylidene fluoride are prepared by electrospinning.The loading of magnesium ferrite is varied from 1 to 10 wt%.The ... The sub-micron(of the order of 150 nm) thick core–shell composite fibers of magnesium ferrite-polyvinylidene fluoride are prepared by electrospinning.The loading of magnesium ferrite is varied from 1 to 10 wt%.The study results by X-ray diffraction,scanning electron microscope,and infra-red spectroscopy indicate the formation of core–shell structure and an enhancement in the amount of b-phase compared to a-phase in the polyvinylidene fluoride.The particle size of the magnesium ferrite in the fiber is evaluated to be 30 nm.The low frequency dielectric studies indicate that the addition of the magnesium ferrite increases the polarization resulting in the increase in the dielectric constant but decreases the dielectric loss.The magnetization measurements indicate an increased value of coercivity compared to bulk due to the nano-size of the magnesium ferrite.The microwave absorption at the ferromagnetic resonance increases with the increase in the concentration of magnesium ferrite.The resonance field is found to vary with the loading of MFO. 展开更多
关键词 Electrospinning Polymer composites dielectric properties Magnetic properties X-ray diffraction(XRD) Microwave absorption
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