• Title, Summary, Keyword: Expanded metal

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Basic Study in Fabrication and Mechanical Characteristics of Ultra Light Inner Structured and Bonded(ISB) Panel Containing Perpendicularly Woven Metal (수직방향 직조 금속망을 이용한 초경량 금속 내부구조 접합판재의 제작 및 특성에 관한 기초 연구)

  • Jung Chang Gyun;Yoon Seok-Joon;Yang Dong-Yol;Lee Sang Min;Na Suck-Joo;Lee Sang-hoon;Ahn Dong-Gyu
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.5
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    • pp.152-158
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    • 2005
  • Inner structured and bonded panel, or ISB Panel, as a kind of sandwich type panel, has metallic inner structures which have low relative density, due to their dimensional shape of metal between a pair of metal skin sheets or face sheets. Previous works showed that ISB panels containing inner structures formed as repeated pyramidal shapes saved weight up to $60\%$ in condition of same stiffness comparing with solid sheet. In this work, woven metal is adapted to inner structures replacing pyramidal structures. The test specimens of ISB panel containing woven metal made by multi-point electric resistance welding and 3-point bending test have been carried out. The results of experiments and comparisons of process parameters, stiffness and failure mode are discussed.

Mechanical Behavior of New Thin Sandwich Panel Subjected to Bending (새로운 박판샌드위치 판재의 삼점굽힘거동)

  • Lee, Jung-In;Kang, Ki-Ju
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.4
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    • pp.529-535
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    • 2013
  • A new thin sandwich panel composed of an aluminum expanded metal core adhesively jointed with stainless steel face sheets is introduced, and its mechanical behavior under three-point bending is investigated. The strength and stiffness are analyzed theoretically, and the press-formability and strength enhancement are evaluated experimentally. The specimens with the specific configurations exhibit face yielding well before face-core separation, which means that the sandwich panel can be formed by a press without failure. The measured load levels corresponding to the face yielding and the face-core separation agree fairly well with the theoretical estimations. For a given weight, the sandwich panel is superior to a solid panel in terms of strength, stiffness, and press-formability.

Pd-based metallic membranes for hydrogen separation and production

  • Tosti, Silvano;Basile, Angelo
    • Proceedings of the Membrane Society of Korea Conference
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    • pp.25-28
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    • 2003
  • Low cost composite metallic membranes for the hydrogen separation and production have been prepared by using thin Pd-Ag foils reinforced by metallic (stainless steel and nickel) structures. Especially, “supported membranes” have been obtained by a diffusion welding procedure in which Pd-Ag thin foils have been joined with perforated metals (nickel) and expanded metals (stainless steel): in these membranes the thin palladium foil assures both the high hydrogen permeability and the perm-selectivity while the metallic support provides the mechanical strength. A second studied method of producing "laminated membranes" consists of coating non-noble metal sheets with very thin palladium layers by diffusion welding and cold-rolling. Palladium thin coatings over these metals reduce the activation energy of the hydrogen adsorption process and make them permeable to the hydrogen. In this case, the dense non-noble metal has been used as a support structure of the thin Pd-Ag layers coated over its surfaces: a proper thickness of the metal assures the mechanical strength, the absence of defects (cracks, micro-holes) and the complete hydrogen selectivity of the membrane. membrane.

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Enhanced evanescent field force on Mie particles by coupling with surface plasmons (표면 플라즈몬과 결합된 에바네슨트파가 Mie입자에 미치는 광압 분석)

  • Song, Young-Gon;han, Bong-Myung;Chang, Soo
    • Korean Journal of Optics and Photonics
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    • v.12 no.6
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    • pp.437-445
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    • 2001
  • We examine theoretically the properties of the force on Mie particles induced by evanescent fields at a system of multilayer films (including a metal film), at which the surface plasmon resonance is excited by a p-polarized plane electromagnetic wave. An expression of the surface plasmon-coupled evanescent fields produced in Kretschmann (or Sarid) geometry is expanded in terms of vector spherical wave functions, while multiple reflections between the Mie particle and the metal boundary are taken into account. The Cartesian components of the force on Mie particles by the evanescent fields are analytically formulated and numerically evaluated. The force components are increased by one or two orders of magnitude at metal boundaries over those at dielectric boundaries. As a result, we can confirm the possibility of stable manipulation or rotation of a finite-sized object by forces of surface plasmon-coupled evanescent fields.

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A Fundamental Study of the Supersonic Coherent Jet (초음속 코히어런트 제트에 관한 기초적 연구)

  • Jeong, Mi-Seon;Cho, Wee-Bun;Kim, Heuy-Dong
    • Proceedings of the KSME Conference
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    • pp.2139-2144
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    • 2003
  • In steel-making processes of iron and steel industry, the purity and quality of steel can be dependent on the amount of CO contained in the molten metal. Recently, the supersonic oxygen jet is being applied to the molten metal in the electric furnace and thus reduces the CO amount through the chemical reactions between the oxygen jet and molten metal, leading to a better quality of steel. In this application, the supersonic oxygen jet is limited in the distance over which the supersonic velocity is maintained. In order to get longer supersonic jet propagation into the molten metal, a supersonic coherent jet is suggested as one of the alternatives which are applicable to the electric furnace system. It has a flame around the conventional supersonic jet and thus the entrainment effect of the surrounding gas into the supersonic jet is reduced, leading to a longer propagation of the supersonic jet. The objective of the present study is to investigate the supersonic coherent jet flow. A computational study is carried out to solve the compressible, axisymmetric Navier-Stokes equations. The computational results of the supersonic coherent jet are compared with the conventional supersonic jet.

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Analysis of Degradation Phenomena in Arc-Tube of Ceramic Metal Halide Lamp (세라믹 메탈할라이드 램프의 아크튜브 열화현상 분석)

  • Kim, Woo-Young;Lee, Se-Il;Yang, Jong-Kyung;Jang, Hyeok-Jin;Park, Dae-Hee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.12
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    • pp.996-1001
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    • 2010
  • Recently, the demand of ceramic metal halide lamp has been expanded. Therefore, the lamp with high efficiency and long lifetime are increasing and the evaluation of reliability is needed. In this paper, the degradation phenomena of ceramic metal halide lamp was studied. The lamp was tested for 3000 on/off cycles with each cycle having a duration of 20 minutes on and 20 minutes off based on the accelerated aging experiment based on "Reliability Standards RS C 0085". As result, the corrosion of arc tube and leak was appeared from reaction between inner wall of PCA and chemical elements, and distortion of electrode was resulted from difference of thermal expansion between arc tube of PCA and electrode. Also, the efficiency of lamp was decreased by the change of inner pressure, operation temperature, and driving voltage from wall blackening.

A Study on the Compressive Characteristics of Inner Structure Bonded Sheet in the Thickness Direction (접합판재의 두께 방향 압축 특성에 대한 실험 및 연구해석)

  • Cho, K.C.;Kim, J.Y.;Chung, W.J.;Kim, J.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.300-303
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    • 2006
  • Sandwich panel with inner structure is expected to find many applications because of high stiffness to mass ratio. However, low resistance to the pressure in the thickness direction may become a weak point in the forming process. Two pyramid type designs for inner structure are considered. For the resistance characteristics in the thickness direction, finite element simulations are carried out. For one design, experimental results are provided. It is shown that simulation can give a reasonable agreement with experiment. The reasons for the discrepancy are discussed mainly in the geometrical viewpoint. It is observed that most of deformation depends on bending mode. Two designs are compared using simulation.

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Raman Spectroscopic Studies on Two-Dimensional Materials

  • Lee, Jae-Ung;Kim, Minjung;Cheong, Hyeonsik
    • Applied Microscopy
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    • v.45 no.3
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    • pp.126-130
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    • 2015
  • Raman spectroscopy is one of the most widely used tools in the field of graphene and two-dimensional (2D) materials. It is used not only to characterize structural properties such as the number of layers, defect densities, strain, etc., but also to probe the electronic band structure and other electrical properties. As the field of 2D materials expanded beyond graphene to include new classes of layered materials including transition metal dichalcogenides such as $MoS_2$, new physical phenomena such as anomalous resonance behaviors are observed. In this review, recent results from Raman spectroscopic studies on 2D materials are summarized.

Hydrogen Sensor and Neuromorphic Applications Using Correlated Materials (강상관계 소재를 이용한 수소 센서 및 수소 뉴로모픽 소자)

  • Oh, Chadol;Son, Junwoo
    • Ceramist
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    • v.22 no.1
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    • pp.17-26
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    • 2019
  • The metal-to-insulator transition (MIT) with external stimuli is one of the main issues in correlated oxides. The physical properties are extremely sensitive to band filling, because the MIT is attributed to the strong correlation between electrons in narrow d-band. Since hydrogen is the smallest and lightest element, it is not only likely to doped reversibly in oxides, but also acts as a dopant to provide electrons. The correlated oxides showing MIT are structurally expanded after hydrogenation, and their electrical properties are drastically changed. Researches on this phenomenon have been actively carried out to date. They are of great scientific importance, and the use of this material is very diverse, including the development of next-generation hydrogen sensor, or hydrogen-based neuromorphic devices.

Investigation of Thermal Management Parameters of Metal Hydride Based Hydrogen Storage System (금속수소화물 기반 수소저장시스템의 열관리 인자 조사)

  • PARK, CHU SIK;KIM, JONG WON;BAE, KI KWANG;JEONG, SEONG UK;KANG, KYOUNG SOO
    • Transactions of the Korean hydrogen and new energy society
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    • v.29 no.3
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    • pp.251-259
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    • 2018
  • Metal hydride based hydrogen storage under moderate temperature and pressure gives the safety advantage over the gas and liquid storage methods. Still solid-state hydrogen storage including metal hydride is below the DOE target level for automotive applications, but it can be adapted to stationary or miliary application reasonably. In order to develop a modular solid state hydrogen storage system that can be applied to a distributed power supply system composed of renewable energy - water electrolysis - fuel cell, the heat transfer and hydrogen storage characteristics of the metal hydride necessary for the module system design were investigated using AB5 type metal hydride, LCN2 ($La_{0.9}Ce_{0.1}Ni_5$). The planetary high energy mill (PHEM) treatment of LCN2 confirmed the initial hydrogen storage activation and hydrogen storage capacity through surface modification of LCN2 material. Expanded natural graphite (ENG) addition to LCN2, and compression molding at 500 atm improved the thermal conductivity of the solid hydrogen storage material.