• Title/Summary/Keyword: Cu Powder

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Improvement of Jc for Ag alloy Sheathed Bi-2223 HTSC Tape (은 합금 시스 Bi-2223 고온초전도 테이프의 임계전류밀도 향상)

  • Jang, H.M.;Oh, S.S.;Ha, D.W.;Ryu, K.S.;Kim, S.H.
    • Proceedings of the KIEE Conference
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    • 1996.07c
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    • pp.1489-1491
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    • 1996
  • The effect of Ag alloy sheath have been investigated in terns of critical current density and mechanical property. Nevertheless the continuous improvement of critical current density($J_c$) of Ag sheathed Bi2223 oxide superconducting wire processed with powder in tube(PIT) method, poor mechanical strength is still considered to be demerits for power application. In this study, we prepared two kinds of Ag- x wt% Cu alloy and pure Ag sheathed Bi2223 superconducting tapes. The hardness and tensile strength of prepared tapes has been measured. Their mechanical propertes were improved by Ag alloying.

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Electrophoretic Deposition of YBCO powder in mixed suspension solution of iso-prophanol and iso-buthanol (이소프로판올과 이소부탄올 용매에서의 YBCO 분말 영동전착)

  • Soh, Dae-Wha;Li, Ying-Mei;Park, Jung-Cheul;N., Korobova
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.288-291
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    • 2001
  • It is very important to select suspension solution for forming electrophoretic deposited YBCO thick mm, because it is heavily affected to its superconducting properties. In this paper, high-temperature superconductor films of $YBa_{2}Cu_{3}O_{7-x}$ were fabricated by electrophoretic deposition (EPD) from alcohol-based suspension such as iso-propanol, iso-butanol, and their mixture. For the formation of YBCO dense and adherent coating on a silver wire by EPD, 1 % PEG(1000) 2 ml, as a additive for making their surface crack-free, was used for electrophoresis. As a results, the cracks were considerably decreased and the superconducting critical current density $(J_e)$ without/with PEG was $1200A/cm^2$ and $2020A/cm^2$, which films deposited in mix iso-propanol and iso-butanol suspension.

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Effect of Additives on Morpholopy of Electrodeposited Dendritic Cu Powder (전해도금욕에서 첨가제의 종류에 따른 수지상 구리 분말의 형상 비교분석)

  • Park, Da-Jeong;Park, Chae-Min;Gang, Nam-Hyeon;Lee, Gyu-Hwan
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2017.05a
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    • pp.167.2-167.2
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    • 2017
  • 수지상 구리분말은 하나의 상(statue)이 복수의 접점(contact point)를 제공하며 표면적이 넓은 구조적인 특징으로 인해 발열기판 전도성 페이스트 등 다양한 전기 전가 분야에 활용되어왔다. 때문에 본 연구에서는 전해도금방법으로 수지상 구리분말이 형성될 때 첨가제가 수지상의 형상에 어떠한 영향을 미치는지 분석하였다. 첨가제는 PEG, JGB를 사용하여 농도별로 실험을 진행하였다. SEM 이미지 분석결과 첨가제가 추가함에 따라 수지상이 미세해지며 첨가제의 농도가 증가함에 따라 DAS(dendrite arm spacing)값이 감소하여 표면적이 증가하였다. BET 비표면적 분석결과 PEG($1.882m^2/g$)보다 JGB($2.119m^2/g$)에서 표면적을 넓히는 효과가 뛰어났다.

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Adsorption of Heavy Metal Ions(Cadmium etc.) using Chitosan Bead (Chitosan Bead를 이용한 Cd등의 중금속 이온의 흡착제거)

  • 권성환;김기환;장문석;유재근
    • Journal of environmental and Sanitary engineering
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    • v.11 no.3
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    • pp.21-27
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    • 1996
  • Chitosan is a natural polyelectrolytic compound. Researches of adsorption capacity using chitosan have been doing actively. We prepared bead type gel, simple modifier of chitosan, And then experimented adsorption test of heavy metals (Cd etc) using it. According to the result adsorption capacity of chitosan bead was five times higher than chitosan powder. Removal rate of cadmium resulted 90% over in the test that initial concentration of Cd was 100mg/L and bead dosage was 6g/100mL. Adsorption type of heavy metals was similar to general adsorption curve. And optical pH range was 4 - 10 in the adsorption test. In the experiments of other heavy metals (Pb, Zn, Cu, Mn) adsorption types had two stages, highly removal rate-stage at the short time (20minutes) and then slow rate-stage at the after. And removal efficiency at the variable pH ranges revealed relatively good.

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Study on the Coordination Polymers of Metal (II) Ions with 2,5-Diamine 1,4-Dihydroxybenzene (2,5-Diamine 1,4-Dihydroxybenzene과 금속 (II) 이온이 만드는 Coordination Polymer에 관하여)

  • Joon Suk Oh;Kyun Ok Cho
    • Journal of the Korean Chemical Society
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    • v.13 no.4
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    • pp.309-312
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    • 1969
  • A series of metal ion-2, 5-diamine 1, 4-dihydroxybenzene polymers containing copper(II), nickel(II) or cobalt (II) have been prepared. The structure was postulated on the basis of elementary analysis of polymers. It was found that copper polymer is most likely the coordination polymers by X-ray powder pattern studies. The thermal stability of the polymers was also studied by a simple method, utilizing a thermogravimetric balance. The order of thermal stabilities is Cu(II) > Ni(II) > Co(II). The polymers start to decompose at a relatively low temperature.

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Analysis of Basic Constituents in Korean Earthworm About Lamnodrilus gotai Hatai (한국산 토룡의 기초성분 분석 -Lamnodrilus gotai Hatai를 대상으로-)

  • Chung, Yong;Lee, Yun-Sil;Lee, Hyo-Min
    • YAKHAK HOEJI
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    • v.31 no.4
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    • pp.224-229
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    • 1987
  • The earthworm(Annelid) is a herbicine which has traditionally been used in the treatment of infectious fever, jaundice, infection of middle ear, laryngitis, pharyngitis, nephritis, headache, toothache and certain urinary tract infections from the olden times. Before the isolation and purification of biologically active components we analyzed the basic constituents(proteins, amino acids, mineral, etc.) with lyophilized powder of Lamnodrilus gotai Hatai. The results were as follows: Minerals detected and quantitatively analyzed were $Ca^#$, $Mg^#$, Fe, Zn, Mn, Cu, Co, Cr, Ni, Ge and Se. Amino acids detected were alanine, phenylalanine, leucine, glutamic acid, tyrosine, threonine, arginine, aspartic acid, methionine, lysine, serine, histidine, isoleucine, glycine, proline and etc. The constituents of proteins, fat, fiber, ash and phosphorous were measured. These constituents were compared and discussed with those of other investigations.

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Novel Bumping Process for Solder on Pad Technology

  • Choi, Kwang-Seong;Bae, Ho-Eun;Bae, Hyun-Cheol;Eom, Yong-Sung
    • ETRI Journal
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    • v.35 no.2
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    • pp.340-343
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    • 2013
  • A novel bumping process using solder bump maker is developed for the maskless low-volume solder on pad (SoP) technology of fine-pitch flip chip bonding. The process includes two main steps: one is the aggregation of powdered solder on the metal pads on a substrate via an increase in temperature, and the other is the reflow of the deposited powder to form a low-volume SoP. Since the surface tension that exists when the solder is below its melting point is the major driving force of the solder deposit, only a small quantity of powdered solder adjacent to the pads can join the aggregation process to obtain a uniform, low-volume SoP array on the substrate, regardless of the pad configurations. Through this process, an SoP array on an organic substrate with a pitch of $130{\mu}m$ is successfully formed.

Determination of Microamounts of Copper by Fluorescence X-Ray Analysis (형광 X-선 분석에 의한 미량 구리의 정량)

  • Choi Won-hyung;Kim Chan-ho
    • Journal of the Korean Chemical Society
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    • v.16 no.6
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    • pp.373-377
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    • 1972
  • The analytical conditions for the fluorescence X-ray determination of small amount of cupper in solution were established. Copper in solution was extracted by diethyldithiocarbamate ethyl acetate and adsorbed by zinc powder. After drying, it was pressed to tablet under the pressure of $250Kg/cm^2.$$K_{\alpha}2(2{\theta}_{LiF} = 45.08^{\circ})$. The limit of detection was estimated to be about $10{\mu}g$ by the method of standard addition with an error of 10 %.

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AC Loss Measurement and Analysis of Ag-sheathed Bi-2223 Conductors in Terms of Eddy Currents and Flux Creep

  • Jang, Mi-Hye
    • KIEE International Transactions on Electrophysics and Applications
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    • v.3C no.6
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    • pp.211-215
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    • 2003
  • Alternating current (AC) losses of two Bi-2223 ([Bi, Pb] : Sr : Ca : Cu :O = 2:2:2:3) tapes [one untwisted (Tape I, twist-pitch of $\infty$ mm) and the other with a twist-pitch of 8mm (Tape II) ] were measured and compared. These samples, produced by the powder-in-tube (PIT) method, are multi-filamentary and have a Ag/Au and Ag matrix, respectively. Susceptibility measurements were conducted while cooling in a magnetic field. Flux loss measurements were conducted as a function of ramping rate, frequency and field direction. The AC flux loss increases as the twist-pitch of the tapes decreased, in agreement with the Norris Equation.

Batch-type fabrication process of YBCO coated conductor using oxide-precursor-based MOD method (산화물 전구체 기반의 MOD방법을 이용한 YBCO 고온초전도 선재의 batch-type 제조 공정)

  • Chung Kook-chae;Yoo Jai-moo;Ko Jae-Woong;Kim Young-Kuk
    • Progress in Superconductivity and Cryogenics
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    • v.7 no.3
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    • pp.9-12
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    • 2005
  • [ $Y_1Ba_2Cu_3O_{7-8}$ ] (YBCO) coated conductor has been fabricated by batch-type process using oxide-precursor-based metal-organic deposition (MOD) method. The batch-type process can be scaled up more simply to Produce long-length YBCO conductor than the reel-to-reel process. Also, it has less handling problems and is adequate to the ambient gas environment. In this work, YBCO oride powder was used as a starting precursor for MOD method. After reel-to-reel dip coating process, me ter-long-buffered metal tape was wound around a cylinder and underwent calcination and annealing processes. Annealed YBCO films showed good c-axis alignment and dense surface morphology with no cracks, but exhibited very low critical current density of $10^5\;A/cm^2$.