• 제목/요약/키워드: Shield Materials

검색결과 243건 처리시간 0.026초

전력케이블용 반도전 재료의 불순물 함량 (Impurity Property of Semiconductive Shield Materials in Power Cables)

  • 양훈;방정환;나창운;박대희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 추계학술대회 논문집
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    • pp.195-196
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    • 2007
  • In this paper, we investigated impurity content of carbon nanotube reinforced semiconductive shield materials and conventional semiconductive shield materials in power cables. To reduce impurity content, we used solution compounding method that an adding process of extra additives neglected. Impurity content measured through ICP-AES(Inductively Coupled Plasma Atomic Emission Spectroscopy). Also, impurity measured Ca, Cu, Fe, Al, Mg, Na, K, Si in eight. As a result, carbon nanotube reinforced semiconductive shield materials is lower than conventional semiconductive shield materials in impurity content by ICP-AES.

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Thermal Protection Shield Concept for Diamond Impregnated Tools

  • Tillmann, W.;Gathen, M.;Kronholz, C.
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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    • pp.875-876
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    • 2006
  • For dry machining of mineral materials the Institute of Materials Engineering pursues a novel thermal protection shield concept for diamond tools, in which thermal insulating materials in diamond composite structures act as heat shield, which protects diamonds in deeper layers against high temperature and graphitisation. Before the effectiveness of this concept could be investigated suitable composites have to be manufactured. In this paper the powder metallurgical production processes of diamond-alumina-cobalt-composites with varying alumina and cobalt particle sizes, their microstructures and porosities are described. It could be observed that the distribution of small-sized alumina particles ($<70{\mu}m$) in the cobalt matrix is uniform and the porosity of the composite decrease.

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도전성 및 자성 차폐체의 차폐효과 해석과 차폐인수 산정 (Analysis of Shielding Effectiveness and Estimation of Shielding Factor in Conductive and Magnetic Shields)

  • 강대하
    • 조명전기설비학회논문지
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    • 제27권10호
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    • pp.30-40
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    • 2013
  • In this study the method based on flux linkage in cell was introduced in calculation of eddy currents by cell method. According to this method eddy current distribution and the loss can be evaluated and since the shielding effectiveness by flux cancelation of eddy current can be analyzed, this method is applicable to design of conductive shield. And also the formula of shielding factor were so deduced as to be applicable to finite-width infinite-length shielding sheets and infinite-length underground cable shield. These formula are adaptable to magnetic materials as well as conductive materials. As the results of calculation in model shields are follows. In case of finite-width infinite-length shielding sheet, shielding effectiveness increases with increasing of conductivity. In case of infinite-length underground cable shield, the effectiveness become higher with increasing of permeability. Especially the effectiveness is very high in materials with both high conductivity and permeability in underground cable shield.

Characteristics of Shield Materials for Wireless Power Transfer

  • Chu, In Chang;Jeong, Jinseong
    • Journal of Magnetics
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    • 제19권3호
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    • pp.291-294
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    • 2014
  • In this paper, we examine the electrical and magnetic properties of three different types of shield materials used for wireless power transfer systems: namely, FeSiAl-composite, NiZn-ferrite, and FeSi-amorphous types. The power transfer efficiency and resistance of an RX coil are measured, while varying the shield thickness. For all three types, a thicker shield provides better power transfer efficiency. Analysis of the measurements shows that the FeSiAl-composite type is suitable for systems with size limitation. In terms of magnetic properties, the FeSi-amorphous type shows the best features, and is suited to high power applications. This work can be used as a guideline to select suitable shielding material in various wireless power transfer systems.

A Practice of Developing New Environment-friendly System by Composites

  • Kim, Yun-Hae;Yang, Dong-Hun;Jo, Young-Dae;An, Seung-Jun;Park, Se-Ho;Yoon, Sung-Won
    • 공학교육연구
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    • 제13권5호
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    • pp.8-14
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    • 2010
  • This study intends to study about the blade performance loss occurred due to the variation in the shape of an airfoil from attachment/non-attachment of an erosion shield for the hovercraft. The model in this study has used NACA44XXseries, has designed NACA44XX-series by using the Auto CAD, and it designed the shape that has attached an erosion shield to this model according to the thickness and length. By using these models, a grid was generated by GAMBIT and the lift coefficient ($C_l$) and the drag coefficient ($C_d$) were calculated FLUENT code for flow analysis. Through this, the $C_l$ and $C_d$ have calculated and compared the lift-to-drag ratio that an indicator of airfoil performance according to the shape and attachment/non-attachment of erosion shield.

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600MPa급 자동차용 고장렬강판의 $CO_2$ 레이저 용접부의 특성에 미치는 보호가스의 영향 (Effect of shield gas on the characteristics of $CO_2$ laser welded 600MPa grade high strength steel)

  • 한태교;이봉근;강정윤
    • 한국레이저가공학회지
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    • 제7권2호
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    • pp.19-26
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    • 2004
  • The effect of shield gas on the weldability, mechanical properties and formability of CO2 laser weld joint in 600MPa grade high strength steel was investigated. Bead on plate welds were made under various welding speed and shield gas. Tensile test was carried out under the load of perpendicular and parallel direction to the weld line, Formability of the joint was evaluated by Erichsen test. As the welding speed increases, the porosity fraction decreases. The porosity fraction in the joint used Ar-$50\%He$ mixed gas as a shield gas was lower than that of the joint used Ar gas. Hardness at the weld metal of full penetrated joint was nearly equal to that of water quenched raw metal. In a tensile test under a perpendicular load to the weld axis, strength and elongation of joint produced by optimum condition were nearly equal to those of base metal. However, the strength of joint in a tensile test under a parallel load to weld axis was higher than that of raw metal, but the elongation of joint was lower than that of raw metal. Elongation and formability were further increased by the method of using Ar+He mixed gas as a shield gas as compared with Ar gas. Formabilities of joints were recorded ranging from $58\%\;to\;70\%$ of that of base metal with different shield gases.

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ABLATING AND CHARRING OF TWO DIMENSIONAL HEAT SHIELD MATERIALS

  • Shabani Mohammad Reza;Rahimian Mohammad Hassan
    • 한국전산유체공학회지
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    • 제10권1호
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    • pp.16-23
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    • 2005
  • The objective of this research is to estimate two dimensional ablating and charring of heat shield materials in severe aero-thermal heat transfer. This estimation requires an accurate and rapid technique for its serious heat transfer with a moving boundary. Aerodynamic heating is obtained by an explicit relation which is a function of Mach number and air condition, while a fully implicit method is used for heat transfer calculations. Moving boundary is captured by FLIAR method which is a subgroup of VOF. Thickness of ablating and charring of heat shield, temperature of the moving surface and rate of radiation heat are calculated and compared with references. The results are in good agreement with other calculations.

ALLMINUM PROTECTIVE HEAT SHIELD 적용연구 (THE APPLICATION OF ALUMINUM SHEET FOR THE PROTECTIVE HEAT SHIELD)

  • 이중윤;이호기;이경남
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1996년도 추계학술대회논문집
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    • pp.166-173
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    • 1996
  • There are kinds of materials for protective heat shield, i.e.Zn-coated steel, AI-coated steel and aluminum alloy sheets. This study compare formability, corrosion resistance, heat protectability, weight, and cost of these materials for heat protective shield. Generally aluminum alloy sheets are less formable than steel sheets, but A1100 alloy sheet shows almost same press quality of steel parts, using the press dies which producing steel parts. The heat shields using aluminum alloy sheet and steel sheet show almost same heat protectibility. It is the conclusion that Zn-coated merit, and AI-coated steel sheet and aluminum alloy sheet can be used to protect functional corrosion in severely corrosive market area. The material cost of AI-coated steel sheet and aluminum alloy sheet for a mid-size car is almost same, so aluminum alloy sheet is more recommendable in the point of weight reduction of vehicle.

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The Effect of Crystal and Non-Crystal Structures on Shielding Material Behaviour Under A.C. Field Excitations

  • Rahman, Nazaruddin Abd;Mahadi, Wan Nor Liza
    • Journal of Magnetics
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    • 제18권1호
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    • pp.9-13
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    • 2013
  • Shielding effects in conductive and magnetic materials were investigated as a function of properties, thickness and diameter. In this work, evaluations on passive conductive and magnetic shield specimens were achieved through experimentation set-up using 50 Hz single and three phase induction field sources. Analysis on material microstructure properties and characteristics of shielding specimens were performed with the use of vibrating sample magnetometer (VSM) and field emission scanning electron microscopy (FESEM). An induction field at $136{\mu}T$ of single phase system and $50{\mu}T$ of three phase systems were observed to the shield specimens with the thickness ranged of 0.2 mm to 0.4 mm. It is observed that shield specimen efficiency becomes inversely proportionate to the increment of induction fields. The decrease was attributed to the surface structure texture which relates to the crystallization and non-crystallization geometrical effects.

지중 전력케이블용 절연재료의 열적 특성 및 기계적 특성 (Thermal and Mechanical Properties of Insulation Materials for Underground Power Cable)

  • 이경용;이관우;최용성;박대희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
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    • pp.138-141
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    • 2004
  • In this paper, we Investigated effects on impurities and water of semiconductive shield through a thermal, mechanical, and absorption experiment to estimate performance of insulating materials in power cable. Specimens had been prepared 22[kV], 154[kV] XLPE power cables and then were made of sheet form with XLPE and semiconductive shield with dimension of 0.4[mm] ~1.2[mm] of thickness from power cable. Heat capacity $({\Delta}H)$ and glass trasition temperature (Tg) of XLPE sheet were measured by DSC (Differential Scanning Calorimetry). We could know that thermal stabilities of 154[kV] are more excellent than 22[kV] from this experimental result. The strain of mechanical properties in 22[kV] and 154[kV] XLPE was 486[%], 507[%] and stress was 1.74$[kgf/mm^2]$, 1.80$[kgf/mm^2]$. The absorption contents of existing semiconductive shield were measured 710[ppm] to 1,090[ppm], and semiconductive shield of 22[kV] cable was measured 14,750[ppm] to 24,780[ppm]. We thermal and mechanical properties of 154[kV] could know more excellent than 22[kV] from this experimental result.

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