• Title, Summary, Keyword: Nickel mesh

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Novel Process of Precision Nickel Mesh Fabrication for EMI Shielding Using Continuous Electroforming Technique (연속전주공정을 이용한 전자파 차폐용 정밀니켈메쉬 제조 신공정)

  • Lee Joo-Yul;Kim Man;Kwon Sik-Chol;Hue Nguyen Viet;Kim In-gon
    • Journal of the Korean institute of surface engineering
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    • v.38 no.6
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    • pp.212-215
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    • 2005
  • Novel continuous electroforming process equipped with a rotating patterned mandrel, soluble/insoluble anode and multiple stage of rolling wheels was proposed to produce precision nickel mesh, which is known as a very efficient electromagnetic interference (EMI) shielding material. Continuously electroformed nickel deposits showed a tendency to form small-sized particles as the plating solution temperature increased and mandrel rotation speeded up and the applied current density decreased. Along the honeycomb patterns of mandrel, nickel was accurately electrodeposited on the surface of rotating mandrel, but quite different visual/structural characteristics were measured on both sides.

Determination of Metals of Coal and Respirable Coal Dust in Gangneung and Taebaek Coal Mines (강릉·태백지역 석탄광산의 탄 및 호흡성 탄분진중 금속 농도 비교에 관한 연구)

  • Kim, Hae Jeong;Choi, Ho Chun;Chung, Ho Keun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.1 no.1
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    • pp.82-88
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    • 1991
  • Determination of Cu, Fe, Ni, Pb, and Zn concentrations in coal and respirable coal dust were performed by atomic absorption spectrophotometry. The coal samples of 18 coal mines in Gangneung area were collected and 25 coal mines in Taebaek area. Crushed coal samples were divided into three mesh sizes. The results were as follows : 1. Metal concentrations of coals in Gangneung area by sieve sizes( -100/+200 mesh, -200/+325 mesh, -325 mesh) were as follows: Cu ; 20, 18, 19, Fe ; 1,830, 1,765, 1,107, Pb ; 6, 8, 14, Ni ; 17, 17, 14, Zn ; 4, 2, $4{\mu}g/g$, respectively. Metal concentrations in coals in Taebaek area by sieve sizes(-100/+200 mesh, -200/+325 mesh, -325 mesh) were as follows: Cu ; 30, 32, 26, Fe ; 1,741, 1,822, 1,773, Pb ; 8, 9, 7, Ni ; 13, 13, 13, Zn ; 8, 5, $4{\mu}g/g$, respectively. There were not significant differences of Cu, Fe, Ni, Pb, and Zn concentrations of coals statistically in Gangneung and Taebaek area by sieve size. 2. Metal concentrations of coals in Gangneung and Taeback area were as follows : Cu ; 19, 30, Fe ; 1,514, 1,778, Pb ; 9, 8, Ni ; 16, 13, Zn ; 3, $6{\mu}g/g$, respectively. Differences of copper and zinc concentrations of coal samples were significant between Gangneung and Taebaek area, but those of iron, nickel and lead concentrations were not significant. 3. Copper, iron, lead, nickel and zinc concentrations of coals and respirable coal dust were as follows : Cu ; 30, 6, Fe ; 1,779, 5,075, Pb ; 8, 7,814, Ni ; 13, 5,681, Zn ; 5, $134{\mu}g/g$, respectively. Differences of nickel, lead and zinc concentrations were significant between coals and respirable coal dust but those of copper and iron concentrations were not significant.

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A Study on the Fabrication of Porous Nickel Substrates Using Graphite Powder (흑연분말을 이용한 다공성 니켈지지체의 제조에 관한 연구)

  • 박성용;백지흠;조원일;조병원;윤경석
    • Journal of the Korean institute of surface engineering
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    • v.28 no.5
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    • pp.276-288
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    • 1995
  • A nickel mesh and an expanded nickel sheet were used as a current collector for supporting active materials of cathode in rechargeable batteries, while a porous nickel substrate was extensively studied because of its 3-dimensional structure which has high capabilities for active materials and current collection. Optimum coating conditions were studied by SEM and two step d. c. constant current electrolysis for the graphite coating and electro-plated nickel on an urethane substance which was highly porous and 3-dimensional structure. The density and the porosity of nickel support obtained by using two step current density and 80 ppi urethane substance were 0.38∼0.40 g /㎤ and 94∼96%, respectively. It was possible to fabricate a highly porous and good packable nickel substrate using two step current density and surfactants at sulfamic acid nickel plating bath.

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Improving the Long-term Field Emission Stability of Carbon Nanotubes by Coating Co and Ni Oxide Layers

  • Choe, Ju-Seong;Lee, Han-Seong;Lee, Nae-Seong
    • Proceedings of the Materials Research Society of Korea Conference
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    • pp.18.1-18.1
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    • 2011
  • Some applications of carbon nanotubes (CNTs) as field emitters, such as x-ray tubes and microwave amplifiers, require high current emission from a small emitter area. To emit the high current density, CNT emitters should be optimally fabricated in terms of material properties and morphological aspects including high crystallinity, aspect ratio, distribution density, height uniformity, adhesion on a substrate, low outgassing rate during electron emission in vacuum, etc. In particular, adhesion of emitters on the substrate is one of the most important parameters to be secured for high current field emission from CNTs. So, we attempted a novel approach to improve the adhesion of CNT emitters by incorporating metal oxide layers between CNT emitters. In our previous study, CNT emitters were fabricated on a metal mesh by filtrating the aqueous suspensions containing both highly crystalline thin multiwalled CNTs and thick entangled multiwalled CNTs. However, the adhesion of CNT film was not enough to produce a high emission current for an extended period of time even after adopting the metal mesh as a fixing substrate of the CNT film. While a high current was emitted, some part of the film was shown to delaminate. In order to strengthen the CNT networks, cobalt-nickel oxides were incorporated into the film. After coating the oxide layer, the CNT tips seemed to be more strongly adhered on the CNT bush. Without the oxide layer, the field emission voltage-current curve moved fast to a high voltage side as increasing the number of voltage sweeps. With the cobalt-nickel oxide incorporated, however, the curve does not move after the second voltage sweep. Such improvement of emission properties seemed to be attributed to stronger adhesion of the CNT film which was imparted by the cobalt-nickel oxide layer between CNT networks. Observed after field emission for an extended period of time, the CNT film with the oxide layer showed less damage on the surface caused by high current emission.

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A Study on the Fabrication of Porous Nickel Substrates (다공성 니켈지지체의 제조에 관한 연구)

  • 신동엽;조원일;백지흠;조병원;강탁;윤경석
    • Journal of the Korean institute of surface engineering
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    • v.28 no.3
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    • pp.123-132
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    • 1995
  • While a nickel mesh and an expanded nickel sheet are used as current collectors for supporting active anode materials in rechargeable batteries, a porous nickel substrate is studied extensively for its 3-dimensional structure which has high capabilities for active materials and current collection. Optimum plating conditions were studied by polarization measurement. Scanning Electron Microscopy (SEM) showed that both electroless-and electro-plated nickel on an urethane substrate were highly porous and consisted of nearly spherical pores. The diameter and the channel size of the pores were found to be 300~500 $\mu\textrm{m}$ and 50~200$\mu\textrm{m}$, respectively. The shape of skeleton resembled a triangular prism with length extending about 50~100 $\mu\textrm{m}$.

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Nickel Mesh for EMI Shielding by Continuous Electroforming (전주도금법에 의한 전자파 차폐용 Ni메쉬 제조기술)

  • Kim, Man;Gwon, Sik-Cheol;Park, Sang-Eon;Lee, Gyeong-Ryeol
    • 연구논문집
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    • pp.183-190
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    • 2003
  • Today, We have used many electronic equipment such as computer, TV, cellular phone and so on. These equipment radiate a large amount of EMI(Electromagnetic interference) which is occurred trouble of airplane, medical equipment, communicate equipment, and especially, human health. So, Ni mesh fabrication for EMI shielding by continuous electroforming process was investigated. Continuous electroforming apparatus was made by means of rotating cathode drum. And We investigated the characteristics of two types of Ni electroforming solution. One was made by laboratory and the other was produced by M cooperation. The grain size increased with increasing current density and bath temperature, and decreasing rotating speed of cathode drum. EDX results indicate that the Ni mesh electroformed by the KIMM solution is composed of pure Ni. But the Ni mesh electroformed by the M cooperation solution has Ni and S element. The incorporation of S element in the Ni mesh has a profoundly effect on mechanical properties such as hardness, internal stress and so on.

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Measurement of the Particle Current Changes Associated with the Flatness of Deflector Mesh Surface in Particle Beam Mass Spectrometer System

  • Kim, Dongbin;Kim, TaeWan;Jin, Yinhua;Mun, Jihun;Lim, In-Tae;Kim, Ju-Hwang;Kim, Taesung;Kang, Sang-Woo
    • Applied Science and Convergence Technology
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    • v.25 no.2
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    • pp.25-27
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    • 2016
  • The surface flatness of metal meshes in a deflector of particle beam mass spectrometer (PBMS) required ideally flat, and this can specify the particle trajectories which goes through the detector. In this research, charged particle current was measured using the different surface roughness deflectors. NaCl particles were generated monodispersed in its size by using differential mobility analyzer and the whole processes were followed the way calibrating PBMS. The results indicate that the mesh surface morphology in the deflector can affect to the particle size and the concentration errors, and sensitivity of PBMS.