• Title/Summary/Keyword: Cu-sheath

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The Design and Manufature by Analysis of AC Loss of high temperature supercondutor wire of Ag-sheath Bi-2223 (Ag-sheath Bi-2223 고온 초전도 선재 AC 손실 해석에 따른 설계 및 제작)

  • Jang, Mi-Hae;Chu, Yong;Lee, Joon-Young;Ko, Tae-Kuk
    • Proceedings of the KIEE Conference
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    • 1998.07a
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    • pp.349-352
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    • 1998
  • In future superconducting electrical machines and device. AC loss in the superconducting windings are one of the most impotent design paramenters. This paper descriptions a series of Characteristic of a high-Tc superconducting Bi-Pb-Sr-Ca-Cu-O Ag-sheathed filament. In the case simulation and design to reduce ac loss is considered the filament number, twitch pith number and diameter of filament. A filament sample with Tc of 78K is made by $835^{\circ}C$ sintering for 50h and $0.33^{\circ}C$/min heating rate in an atmosphere. The experiment observations are compared with self-field loss and AC losses of Bi-Pb-Sr-Ca-Cu-O filament at 77K in following environments ; (i)AC external parallel magnetic field in different frequencies. And an analytical expression of the loss the derivation of transposition from an optimum condition was derived for the external AC magnetic field, theoretical predictions were found to coincide with the experimental observations.

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Adhesion of Cu on Polycarbonate with the Condition of Surface Modification and DC-Bias Sputtering Deposition (폴리카보네이트에서의 표면개질 조건과 DC-Bias Sputtering 증착에 따른 Cu 밀착성)

  • 배길상;엄준선;이인선;김상호;고영배;김동원
    • Journal of the Korean institute of surface engineering
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    • v.37 no.1
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    • pp.5-12
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    • 2004
  • The enhancement of adhesion for Cu film on polycarbonate (PC) surface with the $Ar/O_2$ gas plasma treatment and dc-bias sputtering was studied. The plasma treatment with this reactive mixture changes the chemical property of PC surface into hydrophllic one, which is shown by the variation of contact angle with surface modification. The micro surface roughness that also gives the high adhesive environment is increased by the $Ar/O_2$ gas plasma treatment. These results were observed distinctly from the atomic force microscopy (AFM). The negative substrate dc-bias effect for the Cu adhesion on PC was also investifated. Accelerated $Ar^{+}$ lons in sheath area of anode bombard the bare surface of PC during initial stage of dc bias sputtering. PC substrate. therefore, has severe roughen and hydrophilic surface due to the physical etching process with more activated functional group. As dc-bias sputtering process proceeds, morphology of Cu film shows better step coverage and dense layer. The results of peel test show the evidence of superiority of bias sputtering for the adhesion between metal Cu and PC.C.

Characterization of Manufacturing Process of Metal Fibers of Stainless Steel and Titanium (스테인레스 스틸 극세사와 Ti 극세사 제조 특성 평가)

  • Kim T. H.;Ko J. H.;Lee D. B.
    • Korean Journal of Materials Research
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    • v.15 no.1
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    • pp.37-41
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    • 2005
  • Stainless steel fibers with a diameter of $17\;{\mu}m$ and 630 nm were produced from stainless steel wires by the drawing/annealing/exfolitation process. The suitable sheath material to draw the core stainless steel wires to fibers was the Cu coating. The low melting metal of Zn was not a suitable sheath coating. Also, an attempt was made to produce $20\;{\mu}m{\Phi}Ti$ fibers from the core titanium wires. The main obstacles in producing Ti fibers were their resistance to deformation owing to the Ti's hop structure, and high reactivity of Ti with the exfolitation solution.

Variation of Copper Content in Paddy Soil and Rice from Mangyeong River Area (만경강 유역의 논토양과 수도체중 Cu 함량의 변화)

  • Kim, Seong-Jo;Lee, Man-Sang;Ryu, Taek-Kyu;Kim, Un-Sung;Yoon, Ki-Woun;Baek, Seung-Hwa
    • Korean Journal of Environmental Agriculture
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    • v.13 no.1
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    • pp.10-17
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    • 1994
  • To investigate differences with the polluted sources on Cu contents in soils and paddy rices under water pollutions, soils with the distance, the surface(0-15㎝ depth) and subsurface(15-30㎝ depth) in 1982 and 1990, and rice plants at the soil sampling sites in 1990 were separately sample at Mangyeong River area under the influence of municipal and industrial waste water from Jeonju city. Soil samples were extracted with $4M-HNO_3$ and plant samples were digested with mixture of $HNO_3$ and $HClO_4$ for analyzing Cu, Cd, Zn, Pb by atomic absorption spectrophotometry. Cu contents in soils ranged from 5.20 to 71.70 mg $kg^{-1}$. Average Cu level in 1990 was higher than that in 1982. Variation of Cu content with the distances from the source of waste water in 1990 was more regularly decreased than that in 1982. A significant correlation was observed between Cu contents in leaf sheath of rice plant and Cu, Zn and Pb contents in soils. Cu contents in soil was correlated with Zn and Pb in soil at area affected by waste water, regardless of years and soil depths. Cu contents in brown rice ranged from 0.4 to 10 mg $kg^{-1}$, and it was the lowest in parts of rice plant, and Cu content in panicle axis was 2.3 times higher than that in brown rice.

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Extrusion Process Analysis of Al/Cu Clad Composite Materials by Finite Element Method (유한요소법을 이용한 Al/Cu 층상복합재료의 압출공정해석)

  • 김정인;강충길;권혁천
    • Composites Research
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    • v.12 no.5
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    • pp.87-97
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    • 1999
  • A clad material is a different type of the typical composites which are composed of two or more matericals joined at their interface surface. The advantge of cald material is that the combination of different materials can satisfy both the need of good mechanical properties and the other demand of user such as electrical properties instantaneously. This paper is concerned with the direct and indirect extrusion processes of copper-clad aluminum rod. Extrusion of copper-clad aluminum rod was simulated using a commercially available finite element package of DEFORM. The simulations were performed for copperclad aluminum rod to predict the distributions of temperature, effective stress, effective strain rate and mean stress for sheath thicknesses, die exit diameters and die temperatures.

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Study on terminal shape and pressure for contact type Ic measurement of long Bi-2223 tape (Bi-2223 초전도 테이프의 접촉식 Ic 측정을 위한 단자 형상 및 압력 조사)

  • Ha, D.W.;Yang, J.S.;Ha, H.S.;Oh, S.S.;Kwon, Y.K.;Ryu, K.S.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.04a
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    • pp.25-28
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    • 2002
  • Contact type Ic measurement system is needed to measure Ic continuously for long Bi-2223 tapes. Voltage and current terminals were designed several shapes for 4-probe method Ic measurement. Voltage terminals were made with brass and current terminals were made with Cu. We used 2 kinds of Bi-2223 tapes with different strength. When we measured Ic of Bi-2223 tape with Ag-Mg sheath, The proper weight was 0.3 kg and sharp pin type was better. according to voltage terminal shape and load. In case of Bi-2223 tape with Ag-Mn sheath, the proper terminal weight was 4 kg and sharp pin type was bad. It was possible to make continuous contact type Ic measurement system because We could get proper data - terminal shapes and loads - through these experiments.

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Jangdo(Small Ornamental Knives) manufacturing process and restoration research using Odong Inlay application (오동상감(烏銅象嵌)기법을 활용한 장도(粧刀)의 제작기술 및 복원연구)

  • Yun, Yong Hyun;Cho, Nam Chul;Jeong, Yeong Sang;Jang, Chu Nam
    • Korean Journal of Heritage: History & Science
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    • v.49 no.2
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    • pp.172-189
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    • 2016
  • In this research, literature research on the Odong material, mixture ratio, casting method and casting facility was conducted on contemporary documents, such as Cheongong Geamul. Also, a long sword was produced using the Odong inlay technique. The sword reproduction steps were as follows; Odong alloying, silver soldering alloying, Odong plate and Silver plate production, hilt and sheath production, metal frame and decorative elements, such as a Dugup (metal frame), production, Odong inlay assembly and final assembly. For the Odong alloy production, the mixture ratio of the true Odong, which has copper and gold ratio of 20:1, was used. This is traditional ratio for high quality product according to $17^{th}$ century metallurgy instruction manual. The silver soldering alloy was produced with silver and brass(Cu 7 : Zn 3) ratio of 5:1 for inlay purpose and 5:2 ratio for simple welding purpose. The true Odong alloy laminated with silver plate was used to produce hilt and sheath. The alloy went through annealing and forging steps to make it into 0.6 mm thick plate and its backing layer, which is a silver plate, had the matching thickness. After the two plates were adhered, the laminated plate went through annealing, forging, engraving, silver inlaying, shaping, silver welding, finishing and polishing steps. During the Odong colouring process, its red surface turns black by induced corrosion and different hues can be achieved depending on its quality. To accomplish the silver inlay Odong techniques, a Hanji saturated with thirty day old urine is wrapped around a hilt and sheath material, then it is left at warm room temperature for two to three hours. The Odong's surface will turn black when silver inlay remains unchanged. Various scientific analysis were conducted to study composition of recreated Odong panel, silver soldering, silver plate and the colouring agent on Odong's surface. The recreated Odong had average out at Cu 95.57 wt% Au 4.16wt% and Cu 98.04 wt% Au 1.95wt%, when documented ratio in the old record is Cu 95wt% and Au 5wt%. The recreated Odong was prone to surface breakage during manufacturing process unlike material made with composition ratio written in the old record. On the silver plate of the silver and Odong laminate, 100wt% Ag was detected and between the two layers Cu, Ag and Au were detected. This proves that the adhesion between the two layers was successfully achieved. The silver soldering had varied composition of Ag depending on the location. This shows uneven composition of the silver welding. A large quantities of S, that was not initially present, was detected on the surface of the black Odong. This indicates that presence of S has influence on Odong colour. Additional study on the chromaticity, additional chemical compounds and its restoration are needed for the further understanding of the origin of Odong colour. The result of Odong alloy testing and recreation, Odong silver inlay long sword production, scientific analysis of the Odong black colouring agent will form an important foundation of knowledge for conservation of Odong artifact.

Re-conservation of the Iron Sword with Ring Pommel with Three-Pointed Leaf Decoration Excavated from Tomb No. 55 at the Dalseong Ancient Tomb Complex in Daegu and a Study of Its Production Method (대구 달성 55호분 출토 삼엽문이자태도의 재보존처리와 제작 기법 연구)

  • Lee, Huisung;Huh, Ilkwon;Ro, Jihyun;Park, Seungwon
    • Conservation Science in Museum
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    • v.24
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    • pp.1-16
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    • 2020
  • This paper presents the process of re-conservation and the results of research on the production method of the Iron Sword with Ring Pommel with Three-Pointed Leaf Decoration, one of the excavation findings from Tomb No. 55 in the Dalseong Ancient Tomb Complex in Daegu. This iron sword is a double weapon with two large swords housed within a single sheath. Four smaller swords are attached to the surface of the sheath, two on the upper portion and the other two below. It is the only such two-in-one weapon excavated intact thus far from an ancient Korean tomb. The records show that it underwent conservation treatment twice in the past. In this study, it was subjected to conservation treatment again to replace the stiffener in some cracking areas, and its material, composition, and production method were analyzed by CT, XRF analysis, and stereoscopic microscopy. The sword is mainly made of copper, but the golden component contains both gold and mercury, which suggests that the copper was plated in gold using mercury amalgamation. The examination of the production methods indicates that it was intended more to demonstrate the authority of its owner rather than to serve any practical use. The two upper small swords on the sheath were made in the same manner as the main swords, and the two small lower swords were cut from a single metal sheet. The sheath was made by cutting two metal sheets. Supports were used to attach the two small swords to the upper portion of the sheath, while the lower portion of the sheath was slit to allow the other two small swords to be inserted into it. The ring pommels of the main swords have a three-pointed leaf decoration. As for the other designs, the handle of the main sword features a series of semicircles, the decorative bands on the sheath have waves in dots, and the fish tail of the sheath shows diagonal lines of dots.