• Analytical Science and Technology
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• v.27 no.1
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• pp.11-21
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• 2014

An investigation of grain size, organic compounds and metal distribution in 23 sediment samples of the Geum-River basin (Korea) was conducted in two seasons of 2012 (dry season and rainy season). The samples of sediment were collected from the basin and investigated for concentrations of some metal and general indexes containing grain size. Concentrations of Pb, Zn, Cu, Cr, Ni, As, Cd, Hg, Al and Li have been determined by inductively coupled plasma spectrometer (ICP) and the sediments organic matter content was determined by the loss on ignition, and sediments were fractionated with three different nylon sieves. Correlation analysis was made for grain size, organic material and metal concentrations, and the Pearson correlation coefficients between their concentrations were determined. As a result, the higher metal concentrations were found in the period of the dry season than in another season. The metal concentrations showed high correlation with that of organic material (COD and TOC). Thereby, the high distribution of metal concentrations in sediment containing high organic compound is suggesting an interaction with organic matter.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.1
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• pp.55-62
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• 2015

The electromagnetic force induced by an intense electric current pulse, which generates an electromagnetic field around the metal jet originating from a shaped charge, can disperse and scatter the high-speed metal jet. An electric device consisting of an RLC circuit applies an intense electric current pulse that flows in the circuit while the metal jet passes between two electrodes. In this study, the metal jet formation was simulated using the ALE technique in 2-D, and a 3-D finite element model was mapped using 2-D simulation results to induce the electric current directly. The deformed shapes of the metal jet and the electromagnetic force were calculated using a finite element analysis by inducing the electric current directly, and the major parameters of the intense electric current pulse for breaking up the metal jet were examined.

• Resources Recycling
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• v.11 no.1
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• pp.9-18
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• 2002

Printed wiring boards(PWBs) of the obsolete computers are composed of various organic and inorganic compounds as well as metals and alloys. As convinced that the valuable metals obtained from the PWBs are effectively utilized as secondary resources when recovered by economical methods, in this study, an investigation for characterizing the physical separation techniques is conducted. For the recovery of them, the sockets and chips dismantled from PWBs by scraping and residual resin boards are subjected to the appropriate separation processes according to the physical properties of each part. In the case of crushed socket scraps size ranged from -2.36 mm to +1.18 mm, approximately 97 wt% of the product obtained by magnetic separation consists of metallic compounds. In the case of chip scraps, 97% of Fe-Ni alloy and 95% of Cu metal are recovered by the combined process of air classification and dry magnetic separation in the size range from -2.36 mm to +0.15 mm. Ball milling is adopted in order to improve the removal efficiency of the thin-printed metallic materials on the residual resin boards and approximately 77% of Cu metal is recovered by zigzag separation after ball milling.

• KEPCO Journal on Electric Power and Energy
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• v.6 no.4
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• pp.389-392
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• 2020

In order to accurately predict the losses in the power cable, analysis of the eddy current losses in the metal sheath is required. The copper loss is easily calculated by the resistance and current of the conductor, but it is difficult to measure and predict the eddy current generated from the metal sheath. For this purpose, the previous study analyzed the eddy current loss in single phase cable, but there is a limit to apply it because three phase cables are used in real environment. Therefore, in this paper, the eddy current loss occurring in the metal sheath of three phase cable according to the cause was analyzed theoretically. In addition, the eddy current loss occurring in the triangular and horizontal array were predicted through electromagnetic numerical analysis.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.3
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• pp.60-70
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• 2012

Zn, Cu, Fe, Al contents of sludges produced from sewage treatment plants and night soil treatment plant in Pocheon City, Gyeong-gi Province were investigated. And the accumulated contents of those metals in the earthworm Eisenia fetida were also investigated while 15, 30, 45, 60, 75, 90, 105 grams(dw) of sludges were cumulatively supplied to the earthworms. Zn contents of sludges were 75.1~196.1 mg/kg, Cu contents 3.74~76.1 mg/kg, Fe contents 219.9~857.8 mg/kg, Al contents 198.4~991.7 mg/kg, all of which would not cause acute toxicity to the earthworm, but could cause sublethal effects on earthworm and reduce the density of next generation's population. However, cumulative supplies of sludges didn't increase the bioaccumulation rates of metals in the earthworm body, and BAFs of those metals after 60g of sludge supply were 0.0~0.43, which meant that the accumulated Zn, Cu, Fe, Al contents in the earthworm were lower than those of sludges.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.56-56
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• 2011

알코올 환원법(alcohol reducing process)은 화학적 환원제가 필요하지 않은 화학합성법으로 메탄올, 에탄올, 프로판올, 이소프로판올, 부탄올 등 C1-C4의 알코올류, 에틸렌 글라이콜, 디에틸렌 글라이콜, 프로필렌 글라이콜과 같은 글리콜류 등이 용매이자 환원제로써 사용된다. 전형적으로 금속 전구체를 상기의 알코올류나 글리콜류에 용해 또는 분산시킨 후 그 용액을 환류 조건하에서 가열하게 되면 금속 이온과 용매간의 산화, 환원반응에 의하여 금속이온이 금속원자로 환원되며, 환원된 금속 입자들은 핵 행성과 성장 과정을 거쳐서 입자를 형성하게 된다. 본 연구에서는 알코올환원법을 이용하여 나노크기의 은입자제조를 시도하였고, 이를 PET 칩과의 마스터배치 제조을 시도하였으며, 이의 항균성능을 연구 고찰하였다. 30 ~ 80 nm의 은파우더를 제조할 수 있었으며, 우수한 항균성능을 갖는 Ag/PET 마스터배치를 제조할 수 있었다. 이를 활용하여 나노은입자기반의 항균섬유을 제조하여 이를 활용한 기모경편성물 제조의 기초데이타로 활용이 가능하리라고 사료된다.

• Analytical Science and Technology
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• v.9 no.4
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• pp.373-381
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• 1996

Algal biomass was used in our study in order to remove some metals. After packing of 40~60 mesh algae powder into column for use of metal adsorbent, the metal solution of 1mL/min of flow rate was eluted to adsorb in algae. More amount of Cu(II) or Zn(II) ion in green algae, Ulva pertusa Kjellman than in brown algae, Sargassum horneri (Turner) C. Agarch were adsorbed and Cu(II) ion was more adsorbed in both algae than Zn(II) ion. Recovery of metal from algae is showing higher in acidic or neutral than in alkalic conditions. Cu(II) ion is recovered relatively higher than Zn(II) ion in our system.

• Journal of Conservation Science
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• v.26 no.1
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• pp.33-41
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• 2010

The archival objects are tangible evidence reflecting public work as forming archives which are administrative, historic, symbolic, cultural and artistic value. They are produced from the various countries so that they have different material and manufacture techniques. However there are difficulties in conservation and management because the material investigation and conservation management system are not established. Therefore this research presents fundamental data for the efficient conservation management by material investigation and condition check metal archival objects. Among the public official presents made of metal, 12 pieces which are discoloration, oxidation, loss or crack are chosen for this research. In order to examine extensive condition of metal archival objects, the condition check card used from the domestic museum and the national museum in Japan are collected and then the new check card is produced. X-ray is used to know the making technique, binding means between different material. Portable-XRF is also used for the chemical composition analysis of metal archival objects, and then classifying respectively according to their material. As a result of condition check, it is possible to investgate the appearance character, deteriorated parts and weak parts of structure. Also P-XRF could find out the composition of metal archival objects which is different from existing condition check card. Therefore the research results can be used as fundamental data for further conservation and management as well as long-term conservation.

• Korean Journal of Heritage: History & Science
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• v.14
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• pp.44-54
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• 1981

• 보존과학연구
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• s.12
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• pp.109-122
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• 1991