Thermodynamic Calculations and Parameter Variations for Improving the Extraction Efficiency of Dy in Ternary Alloy System

Sun‑Woo Nam,Sang‑Min Park,Do‑Hyang Kim,Taek‑Soo Kim 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.3

The extraction behavior of dysprosium (Dy) in a rapidly solidified Dy–Fe–B alloy system consisting of Dy2Fe14Band Dy6Fe23phases was investigated using the liquid metal extraction (LME) process. Liquid magnesium (Mg) was selected as the solventmetal in LME because it forms intermetallic compounds with Dy but not with iron (Fe) and boron (B) in this process. Thediffusion behavior of Dy was estimated through thermodynamic calculations and subsequently confirmed by process parameterssuch as temperature and reaction time. As the temperature increases, the extraction rate increases and the maximumextraction efficiency is about 74% Dy for 1 h at 1000 °C. As the reaction time increases, we achieved the maximum extractionefficiency of 95% Dy after 24 h at 900 °C. The factor affecting Dy extraction ratio up to 6 h is Dy6Fe23phase, after which theextraction mainly occurs in Dy2Fe14Bphase. Furthermore, the diffusion behavior is described in detail with analysis basedon microstructural and compositional properties. The effects of process parameters on extraction rate are also discussed.

고정벽체에 작용하는 횡토압에 대한 모형실험

남선우,김문규,배선호 동아대학교 건설기술연구소 1997 硏究報告 Vol.21 No.2

To examine lateral earth pressure against fixed wall due to geometry of backfill, a model test was carried out. Soil box (180×75×80mm), 2-directional load cell and rainer were made for this test. And Sumjin river sand as backfill materal was placed in the backfill space with different geometries and relative densities. This test result was compared with the extended Silo theory(Chung et at, 1997) and Jaky's lateral pressure at rest. The comparative results are as follows : When the bottom width between the model wall and the stable slope is narrow, the experimental pressure agree well with that of the extended theory, independent of inclinations of wall and stable slope. However, when the width is not narrow, ie, when Bc/H is larger then 0.333, the experimental pressure is preferably close to the Jaky's lateral pressure at rest. The angle of wall friction have an important effet on the experimental lateral pressure, as wall as bottom width. The wall friction angle was measured the peak at lower placing height, and just after that the value is roughly constant up to the residual state.

企業의 所有와 經營의 分離에 관한 小考

南鮮祐 중앙대학교 법학대학 1983 法政論叢 Vol.23 No.-

브리지만법에 의해 성장된 p-GaSe 단결정의 전자 이동도에 관한 연구

이우선,김남오,손경춘 조선대학교 에너지.자원신기술연구소 1999 에너지·자원신기술연구소 논문지 Vol.21 No.1

RF 스퍼터링법에 의한 IC 소자용 티탄산스트롬튬 증착막의 전류-전압 특성

이우선,김남오,정용호 조선대학교 에너지.자원신기술연구소 1998 에너지·자원신기술연구소 논문지 Vol.20 No.2

The objective of this study is to deposited the preparation of SrTiO₃ dielectric thin films on Ag/barrier-mater/Si(N-type 100) bottom electrode using a conventional rf-magnetron sputtering technique with a ceramic target under various conditions. The result indicated that lower leakage current and the capacitance-voltage(C-V) behavior of MIS structures represented dielectric permittivity in the accumulation region and also good Si/SrTiO₃ interface. It is demonstrated that the leakage current of films are strongly dependent on the atmosphere during deposition and the substrate temperature. The conductivity properties of films deposited on silicon substrates were very high conductivity. Capacitance of the films properties were the highest value(1000㎊) and dependent on substrate temperature. The SrTiO₃ films was improved with the increase of the substrate temperature and decrease of the ambient oxygen pressure. SEM analyses showed that SrTiO₃ films had a uniform and fine grain structure.

세라믹 섬유필터를 이용한 디젤 입자상물질 배출저감에 관한 기초연구

주용남,홍민선,문수호,이동섭,임우택 한국대기환경학회 2003 한국대기환경학회지 Vol.19 No.3

Works were focused on back pressure characteristics of ceramic fiber filter on DPF(Diesel Particulate Filter) system and experiments were performed to select appropriate filter which can filter particulates. Filters were installed on metal-support tube which has openings for exhaust as flow. Ceramic fiber filters with high specific surface area and adequate high temperature strength are commercially available for filtration of diesel particulates and in-situ hot regeneration. Thus, ceramic blanket and ceramic board which are used as insulating media were applied to filter and filteration apparatus was installed on exhaust as line connected to 2.0L diesel engine. Alternating filter structure to adapt DPF system, collection efficiency test of diesel particulates was measured. In case of ceramic blanket, pressure drop was low, caused by the destruction of soft structures. Also, particulate collection efficiency was decreased depending on loading time. In case of ceramic board, structure design was altered to reduce back pressure on DPF system. Structure design was altered to induce Z-flow by making 10mm and 5mm holes on the surface of media. Alteration of 5mm hole showed that media have low back pressure but particulate collection efficiency was 77%, while 10mm hole showed that of 90%.

CBD으로 제작한 In:Cd_(1-x)Zn_(x)S/CdTe 태양전지의 전기적 특성에 관한 연구

심재선,송우창,방영근,김남석,임창민,장현 三陟大學校 2006 論文集 Vol.39 No.-

CdS thin films have been widely used a window material in heterojunction solar cells. In solar cell systems, where CdS thin films have been proved to be useful, partial substitution of Zn for Cd increases the optical window of the hetero-junction and also the diffusion potential. In this thesis, effects of the thickness of indium films and the annealing temperature on structural, optical and electrical properties of chemically deposited CdZnS films for the efficiency of the Cd_(1-x)Zn_(x)S/CdTe solar cells were investigated. Cd_(1-x)Zn_(x)S films were grown by chemical bath deposition (CBD), which is a very attractive method for low-cost and large-area solar cells. The open circuit voltage of Cd_(1-x)Zn_(x)S/CdTe solar cells increased due to reduced electron affinity difference between Cd_(1-x)Zn_(x)S and CdTe films. However, the conversion efficiency of Cd_(1-x)Zn_(x)S/CdTe solar cell decreased because of the higher series resistance(R_(s)) than CdS/CdTe solar cell. The series resistance and conversion efficiency of Cd_(1-x)Zn_(x)S/CdTe solar cell were improved by using indium-doped Cd_(1-x)Zn_(x)S films as window layer. Cd_(1-x)Zn_(x)S/CdTe solar cells fabricated with optimal conditions exhibited V_(oc)=630mV, J_(sc)=38.89mA/㎠ , FF=0.53, and η=13.2%

XLPE 절연 케이블의 전기적인 특성

이우선,정창수,김남오 조선대학교 에너지.자원신기술연구소 1999 에너지·자원신기술연구소 논문지 Vol.21 No.2

Electrical characteristics of metal impurities in insulation of distribution cables on electrical conduction of distribution cables was investigated. Samples of Al, Cu, Fe are fabricated as metallic impurities, and measured electrical conductivity in the voltage range of 0~10 ㎸. Capacitance characteristics of hysteresis curves and the relationship between forward and reverse current due to impurity content are discussed.

톱밥과 농산부산물을 이용한 검은비늘버섯(Pholiota adiposa)의 재배

이상선,이정우,조남석 한국목재공학회 2002 목재공학 Vol.30 No.1

본 연구에서는 검은 비늘버섯을 유용한 식용버섯으로 개발하기 위하여 톱밥 및 다양한 농산부산물을 기질로 하여 버섯재배를 실시하였으며, 기질의 홉합비가 버섯재배 및 생산량에 미치는 영향을 구명하고자 하였다. 톱밥을 이용한 버섯재배에서 수종별로는 미류나무가 795 g으로서 가장 많은 버섯이 생산되었으며, 아까시나무가중간정도, 상수리나무가 3수종 가운데 가장 적은 양이 생산되었다. 3수종의 톱밥을 30% 및 50% 비율로 혼합한 배지에서 아까시나무톱밥의 혼합으로 많은 버섯 생산을 결과하였는데, 아까시나무톱밥 70%+미류나무톱밥 30%가 265 g의 버섯을, 아까시나무톱밥 50%+미류나무톱밥 50% 조합에서는 228 g의 높은 버섯생산량을 나타냈는데 대하여, 상수리나무톱밥이 혼합되면 버섯생산량이 낮아졌다. 이러한 결과로부터 톱밥 혼합 배지에서 아까시나무는 부재료로서 매우 가치가 있는 것으로 나타났다. 모든 농산부산물의 경우에도 버섯의 증수효과를 결과하였다. 이러한 결과로부터 검은비늘버섯의 재배에 톱밥, 특히 아까시나무 및 농산부산물을 이용할 수 있음이 밝혀졌다. Cultivation of Pholiota adiposa on sawdust media and its mixed substrates with various agricultural by-products was attempted. The composition of each substrates were compared from the viewpoint of cultivation possibilities with the production of Pholiota adiposa. Populus deltoides showed the best production of the mushroom with 795 g, followed by Robinia pseudo-acacia and Quercus acutissima. The mixed sawdust media with 70% of Robina pseudo-acacia and 30% of Populus deltoides showed the best production of the mushroom with 265 g followed by the mixture of Robinia pseudo-acacia and Populus deltoides with 50% each with 228 g, while the addition of Quercus acutissima showed the negative effect for the production of Pholiota adiposa. Thus, Robinia pseudo-acacia was considered to be an effective amendment for the production of the mushroom. In addition, various kinds of agricultural by-products showed additive effect for the production of the mushroom, too. Therefore, we could concluded that the sawdust of Robinia pseudo-acacia and agricultural by-products can be used to cultivate Pholiota adiposa.

DLPC LB막의 C-V 특성

이우선,정용호,김남오 조선대학교 에너지.자원신기술연구소 1998 에너지·자원신기술연구소 논문지 Vol.20 No.2

MLS capacitor with lipid ultra thin films were deposited by Langmuir-Blodgett (LB) method on the sillicon wafer. The current versus voltage and capacitance versus voltage relationships are depend on the applied voltage, frequency and thickness of LB films. LB films deposited were made of L-α-DLPC, the 1 layer's thickness of 35Å was measured by ellipsometer. The result indicated the lower leakage current and very high saturation value of capacitance was reached within 700-800 ㎊ when the thickness was 275Å.