• Title, Summary, Keyword: Expanded metal

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Development of Aged Fingermarks Deposited on Expanded Polystyrene(Styrofoam) Using Multi-metal Deposition I(MMD I) (Multi-metal Deposition I(MMD I)을 사용한 스티로폼 표면의 오래된 지문 현출)

  • Kim, Chae-Won;An, Jae-Young;Yu, Je-Seol
    • The Journal of the Korea Contents Association
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    • v.20 no.3
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    • pp.687-694
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    • 2020
  • Styrofoam is one of the most commonly used materials in everyday life, such as various packaging containers, toys, and buoys, and is likely to be found in crime scenes. However, due to the structural characteristics of Styrofoam, fingerprints cannot be deposited well. According to previous researches, powdering or cyanoacrylate fuming method was applied for developing fingerprints on Styrofoam. The purpose of this study was to investigate the effect of MMD I through comparative experiments of powdering. As a result of applying powder method and MMD I, MMD I was more effective than powder method on styrofoam.

The Optical Characteristics of 240 W High Power LED Fish Luring Lamp (240W급 고출력 LED 집어등의 광학적 특성)

  • Bae, Jae-Hyun;An, Heui-Chun;Kim, Sang-Woo
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.19 no.6
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    • pp.681-687
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    • 2013
  • This study analyzed characteristics of 240 W high power LED lamps by comparing with those of traditional metal halide lamps. In addition, it analyzed the propriety of LED lamps as a source of light, considering seawater transmission characteristics. When Applying white LED package with the color temperature color temperature of 6500K, a 240W-LED fishing lamp has a characteristics of the luminous angle to be expanded to ${\pm}45^{\circ}$, the illumination change was improved to 0.8, as well as the luminance efficiency was improved to 98.8lm/W. As results of comparison between one 1,500W-metal halide lamp and four 240W-LED lamp with considering a seawater transmission and a luminous efficiency of scotopic vision, the radiant flux of two lamps were almost equal level at 50m depth and the luminous flux was 5% higher LED lamp than metal-halide lamp even if only applying the luminous efficiency of scotopic vision. As the luminous flux of LED lmap was 14% higher than that of metal-halide lamp with applying the luminous efficiency of scotopic vision to radiant flux at 50m depth, so LED fishing lamp was verified to alternative possibility of metal-halide lamp.

Application of Computer-Aided Process Design System for Axisymmetric Deep Drawing Products (축대칭 디프 드로잉 제품에 대한 공정설계 시스템의 적용)

  • Park, S.B.;Park, Y.;Park, J.C.
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.4
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    • pp.145-150
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    • 1997
  • A computer-aided process design system for axisymmetric deep drawing products has been developed. An approach to the system is based on the knowledge based system. The hypothesized process outline of the deep drawing operations is generated in the geometrical design module of the system. In this paper, the module has been expanded. The rules of process design sechems for complex cup drawings are formulated from handbooks, experimental results and empirical knowhow of the field experts. The input to the system is final sheet-metal objects geometry and the output from the system is process sequence with intermediate objects geometries and process parameters, such as drawing load, blank holding force, clearance and cup-drawing coefficient.

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초경량 내부구조 접합판재 제작을 위한 금속내부구조의 설계 변수 분석

  • 정창균;윤석준;성대용;양동열;안동규
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.64-64
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    • 2004
  • 최근 복합재료, 신소재 등 다양한 방법을 통해 빔(beam), 바(bar), 패널(panel) 등 초경량 구조재료가 개발되고 있다. 이중 금속 내부구조재를 가진 접합판재(Inner Structured and Bonded panel, ISB panel)은 3차원 형상의 내부구조재가 강성 및 강도를 증가시키는 반면, 부피의 대부분이 비어있어 비강도 및 비강성을 크게 개선시킨다 일반적으로 다양한 트러스 형태의 금속 내부구조물은 허니컴 형상의 내부구조와 유사한 정도로 기계적 특성이 우수하다.(중략)

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Measurement Uncertainty for Analysis of Residual Carbon in a Tungsten-15% Copper MIM part (텅스텐-15% 카파 사출성형체의 잔류 탄소량 분석에 대한 측정 불확도)

  • Lee, Jeong-Keun
    • Journal of Korean Powder Metallurgy Institute
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    • v.14 no.6
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    • pp.410-414
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    • 2007
  • Carbon contamination from the binder resin is an inherent problem with the metal powder injection molding process. Residual carbon in the W-Cu compacts has a strong impact on the thermal and electric properties. In this study, uncertainty was quantified to evaluate determination of carbon in a W-15%Cu MIM body by the combustition method. For a valid generalization about this evaluation, uncertainty scheme applied even to the repeatability as well as the uncertainty sources of each analyse step and quality appraisal sources. As a result, the concentration of carbon in the W-Cu part were measured as 0.062% with expanded uncertainty of 0.003% at 95% level. This evaluation example may be useful to uncertainty evaluation for other MIM products.

The Effects of Nitrogen Abundance Variations on the Evolutionary Tracks of Low-Mass Stars with Various Metallicities and Helium Contents

  • Na, Chongsam;Han, Sang-Il;Kim, Yong-Cheol;Lee, Young-Wook
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.64.2-64.2
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    • 2013
  • As more spectroscopic observations accumulate, it becomes evident that there are variations in light elements, such as C, N, O, and Na, between the sub-populations in most globular clusters (GC) in the Milky Way. We have constructed a new set of isochrones and horizontal branch evolutionary tracks with enhanced Nitrogen and depleted Oxygen to study their effects on the evolution of stars in GCs. From these results, we found that their effects on the evolution in color-magnitude diagram are significant in determining the age of GCs. In order to reflect these effects in the construction of population models for GCs, we have expanded the parameter space of Yonsei-Yale Isochrones and HB evolutionary tracks by introducing abundance enhancements of N for various global metal abundances and helium contents. In this paper, we will present our preliminary results from these calculations.

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Fabrication of Duplex Ceramic Composites by Organic-Inorganic Solution Process

  • Lee, Sang-Jin;Kim, Youn-Cheol
    • Journal of the Korean Ceramic Society
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    • v.40 no.9
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    • pp.837-841
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    • 2003
  • Duplex microstructure of zirconia and alumina has been achieved via an organic-inorganic solution technique. Zirconium 2,4-pentanedionate, aluminum nitrate and polyethylene glycol were dissolved in ethyl alcohol without any precipitation. The organicinorganic precursor gels were turned to porous powders having volume expansion through explosive, exothermic reaction during drying process. The volume expansion was caused by abrupt decomposition of the organic groups in the gels during the vigorous exothermic reaction. The volume expanded, porous powders were crystallized and densified at 1500$^{\circ}C$ for 1 h. At the optimum amount of the PEG polymer, the metal cations were well dispersed in the solution and a homogeneous polymeric network was formed. The polymer content also affected on the specific surface area of the synthesized powder and the grain size of the sintered composite.

Tendency of PVD coating technology on Metal cutting tools (금속 절삭공구에 대한 PVD 코팅기술의 동향)

  • Kim, Jong-Seong
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.8
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    • pp.11-17
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    • 2001
  • Industrial use of physical vapor deposition(PVD) has been widely expanded during last two decades, and in the mean time plasma assistance in PVD has become an essential tool in preparing compound films with dense microstructure. The principles of electron beam-based plating, balanced and unbalanced magnetron sputtering and cathodic arc deposition. consisting three basic configuration of plasma assisted PVD(PAPVD)process, were reviewed. Recent technical development in PVD coating process were discussed. This paper tries to show tendency for developing new coating film on cutting tools.

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Study on Electrochemical Characteristics and Fabrication of Catalytic Electrode (복합 촉매 전극의 제조 및 전기화학적 특성에 관한 연구)

  • 민병승;정원섭;김광호;민병철;이미혜
    • Journal of the Korean institute of surface engineering
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    • v.35 no.6
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    • pp.401-407
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    • 2002
  • Most of organic compounds discharged from industrial wastewater are treated by chemical oxidation, adsorption and biodegradable process. This process has been demanded a new advanced environmental wastewater treatment process. From this point of view, an electrochemical oxidation process using electrocatalysts has been developed for the destruction of organic compounds. Through this study, a ruthenium oxide/iridium oxide supported on titanium expanded metal was fabricated by thermal decomposition method and its performance was excellent during this experiment.