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Morphologies evolution and mechanical behaviors of SiC nanowires reinforced C/(PyC-SiC)_(n)multilayered matrix composites

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Journal of Materials Science & Technology 2022年第1期96卷 190-198页

作者： Xinfa Tian Hejun Li Xiaohong Shi Hongjiao Lin Ningning Yan Tao Feng State Key Laboratory of Solidification Processing Carbon/Carbon Composites Research CenterNorthwestern Polytechnical UniversityXi’an 710072China School of Mechanics Civil Engineering&ArchitectureNorthwestern Polytechnical UniversityXi’an 710072China

SiC nanowires reinforced C/(PyC-SiC)_(n)multilayered matrix composites(SM-CS for short)were prepared by combined with sol-gel and chemical vapor infiltration(CVI)method.Firstly,(PyC-Si OC);multilayered structure was formed by cycles of impregnation and deposition.Then SiOC was transformed into SiC by heat-treatment,and(PyC-SiC)_(n)multilayered structure would be obtained.At the same time,the PyC layer which was designed as the outmost layer could decrease gas supersaturation to form in-situ tubular SiC nanowires on the surface of multilayered structure.The results of three-point bending test showed that the maximum force of SM-CS composites was increased by the number of cycles of the preparation process,which were up to enhanced by 74.38%compared with C/C composite materials.The fracture surface showed that the improvement was due to the multiscale reinforcing system of(PyC-SiC)_(n)multilayered structure and SiC nanowires.multilayered structure can protect carbon fibers and release stress concentration by induction of cracks.And the mechanical interlocking effect of SiC nanowires could reinforce bonding force of the remaining matrix.

关键词： C/C multilayered structure SiC nanowires Flexural property

Electromagnetic Polarization Converttion by multilayered structure of Metal-dielectric Films on Optical Wave Band

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Electromagnetic Polarization Converttion by Multilayered Str...

Shrinking device realized by using layered structures of homogeneous isotropic materials

2009 3rd IEEE International Symposium on Microwave,Antenna,Propagation and EMC Technologies for Wireless Communications

作者： Lin ZHAO Department of Communication Engineering Naval Univ. of Engineering Wuhan China Ting-ting ZHU Yu-jun LIANG Hui-XIE School of Electronic Engineering Naval Univ. of Engineering Wuhan China

Based on the effective medium theory, anisotropic microwave materials have been realized by a multilayered structure of alternating films. The equivalent material constitutive tensors have been calculated with different film orientations. The prevenient analysis shows that the structure can realize electromagnetic polarization splitter by controlling the orientation of the films on optical wave band. In this paper, the futher research on the structure shows multilayered structure of metal- dielectric films has property of electromagnetic polarization converttion by controlling the plane of incidence. This may lead to new ways of exploring novel polarization converttion materials and structures.

关键词： electromagnetic polarization converttion multilayered structure films

来源： cnki会议评论

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cnki会议

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Chinese Physics B 2012年第6期21卷 179-182页

作者：郭亚楠刘少斌赵鑫王身云陈忱 College of Information Science and Technology Nanjing University of Aeronautics&Astronautics State Key Laboratory of Millimeter Waves of Southeast University

We propose the practical realization of a shrinking device by using layered structures of homogeneous isotropic materials.By mimicking the shrinking device with concentric alternating thin layers of isotropic dielectrics,the permittivity and the permeability in each isotropic layer can be properly determined from the effective medium theory in order to achieve the shrinking effect.The device realized by multilayer coating with dielectrics is validated by TE wave simulation,and good shrinking performance is demonstrated with only a few layers of homogeneous isotropic materials.

关键词： shrinking device effective medium theory multilayered structure

Acoustic carpet invisibility cloak with two open windows using multilayered homogeneous isotropic material

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Chinese Physics B 2011年第11期20卷 353-358页

作者：任春雨向志海岑章志 Applied Mechanics Laboratory Department of Engineering MechanicsTsinghua University Department of Naval Architecture and Ocean Engineering Naval University of Engineering

We present a method for designing an open acoustic cloak that can conceal a perturbation on Hat ground aria simultaneously meet the requirement of communication and matter interchange between the inside and the outside of the cloak. This cloak can be constructed with a multilayered structure and each layer is an isotropic and homogeneous medium. The design scheme consists of two steps： firstly, we apply a conformal coordinate transformation to obtain a quasi-perfect cloak with heterogeneous isotropic material; then, according to the profile of the material distribution, we degenerate this cloak into a multilayered-homogeneous isotropic cloak, which has two open windows with negligible disturbance on its invisibility performance. This may greatly facilitate the fabrication and enhance the applicability of such a carpet-type cloak.

关键词： transformation method acoustic wave carpet cloak multilayered structure

Synthesis and Characterization of Advanced Red Mud and MWCNTs Based EMI Shielding Material via Ceramic Processing

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Materials Sciences and Applications 2016年第4期7卷 192-201页

作者： Sarika Verma Sudhir Sitaram Amritphale Satyabrata Das Council of Scientific and Industrial Research-Advanced Materials and Processes Research Institute Bhopal India

For the first time in the world advanced multi layered Red Mud and MWCNTs (ARMC) based EMI shielding material has been developed at CSIR-AMPRI, Bhopal. Red mud provides oxides of titanium and iron as precursor and the MWCNTs provides electrical conductivity characteristics necessary for making desired EMI shielding materials. The novel process involves unique designing of chemical compositions and mineralogical phases of red mud, MWCNTs together with appropriate additive and solvent which results in the simultaneous and synergistic chemical reactions among various constituents thereby forming tailored precursor powder. Further, the ceramic processing of tailored precursor powder in appropriate environment enables formation of advanced ARMC shielding material having a variety of ceramic phases with multi elemental compositions and multi layered crystal structures. The synthesized material was characterized by various techniques namely XRD, PL, FESEM, EDXA. The reflection loss (R. L.) of the sample was calculated based on the measured complex permittivity and permeability. The advanced ARMC material with thickness t = 1.5 mm showed a minimum R. L. of -35.5 Db at 14.0 GHz with a response band width of 1.8 GHz. Thus, the developed advanced ARMC material acts as a good EMI wave absorber.

关键词： Red Mud MWCNTs EMI Shielding Ceramic Processing multilayered structure