현탁용매에 따른 전기영동 초전도 후막의 영향

소대화,박정철,이영매,조용준,Korobova, Natalya 명지대학교 산업기술연구소 2001 産業技術硏究所論文集 Vol.20 No.-

For the research of the effects on suspension solution with YBcO and BSCCO for elcectrophoretic deposition to prepare superconducting thick film wire, the preheating technique for the superconducting powders in vaccum system was used with various solvent solutions for electrophoresis such as acetone, toluen and buthanol was investigated. As a result, it was useful to remove the influence of remaining and adsorbed solvent solution which was existed between and on the particle surfaces when the specimens of superconducting wire by electrophoresis were treated in vacuum of 10-3 Torr and temperature around 200℃ in bell-jar system. Of the prepared superconducting wire samples, the critical current density, Jc was measured by 4-point prove method in liquid N₂, and at the value of 10³to 10⁴A/㎠, respectively, for the YBCO and BSCCO superconducting wires.

관광동굴의 친환경 조명과 녹색 전원 장치

소대화 明知大學校 産業技術硏究所 2009 産業技術硏究所論文集 Vol.28 No.-

In the cave, there are able to exist CO₂ gas and H₂O humidity from the human breathing and in atmosphere or the underground water, and also the light can be irradiated by the illumination fixtures for tourism and caving. For this reason, the green plants of moss and others could be created and grown on the rock in the cave by the photosynthesis reaction, however, sometimes there would be the dry season to be killed the green mosses and plants, and hence , it could be dried and blackish‘ When the dried mosses were taken off from the surface of the rock like as laminated dried one, the moss lamination could be taken off together with the skin of the formated stalactite in the cave‘ Therefore, the cave environment should be changed and degenerated unfortunately, though it is undesirable‘ So it is necessary to control the cave environment to be better condition somehow by using suitable methods such as selective wave lighting irradiation to make photosvnthesis or not to make it in there bv the lighting fixtures of LED lamps.

현탄액에 따른 전기영동전착 YBCO 초전도 선재 제작

소대화,코로보바 나탈리아,조용준,이영매 明知大學校 産業技術硏究所 2002 産業技術硏究所論文集 Vol.21 No.-

High-Tc superconductor films of YBa2Cu3O7-x were fabricated by electrophoretic deposition (EPD) from alcohol-based suspension, It is very important to select suspension solution for forming electrophoretic deposited YBCO thick film, because it is heavily affected to its superconducting properties. For the formation of YBCO dense and adherent coating on a silver wire by EPD, 1% PEG(1000) 2㎖, as a additive for making their surface crack-free, was used for electrophoresis. In this paper, high-temperature superconductor films of YBa2Cu3O7-x were fabricated by electrophoretic deposition (EPD) from alcohol-based suspension such as iso-propanol, iso-butanol, and their mixture. As a results, the cracks were considerably decreased and the superconducting critical current density (Jc) without/with PEG was 1200 A/㎠ and 2020 A/㎠, which films deposited in 30% iso-PrOH and 70 % iso-BuOH suspensionin mix iso-propanol and iso-butanol suspension.

2005 후반기 학술발표대회 : 풍화작용에 의한 자연변형지물의 지형미학적 고찰 (I)

소대화 한국동굴학회 2005 한국동굴학회 학술발표논문집 Vol.2005 No.1

용신작용에 의한 지형변화에서 지하공간속의 요새화기법을 석회동굴에서 찾아볼 수 있듯이, 여러가지 자연현상 중에서 풍화작용을 같은 원인적 현상에 의한 변형을 통하여 오랜 세월속의 지형지물의 변화에서 나마(gnamma/가마솥바위), 타포니(tafoni/벌집바위) 등의 풍화혈(風化穴/weathering pits)과 같은 기이한 지형물들을 만나볼 수 있다, 특히 우리나라는 대륙에 이어진 반도국가로서 해양성기후권의 해안에서의 해식이나 파식 현상으로 인한 해식애와 파식대 및 해식동굴 등 지형물의 특이한 변화현상이 두드러져 나타나 발견되고 있다. 본 논문은 우리나라 곳곳에 분산되어있는 자연속의 여러 가지 변형지물들을 고찰하기 위하여 먼저 풍화작용과 그 풍화물들에 대한 특이한 지형의 성인과 특징 분석을 통하여 현존 상태의 지형미학적 측면을 비교 관찰하고, 자연의 아름다움과 현경의 중요성을 새롭게 인식하면서 우리의 역할과 가치의 의미를 재조명해보는 현지탐사 활동과 자료조사의 일부이다.

액상-고상반응법과 자기전파고온합성법에 의한 YBCO 초전도체의 특성

蘇大和,코로보바 나탈리아,金泰完 明知大學校 産業技術硏究所 2002 産業技術硏究所論文集 Vol.21 No.-

In this paper, instead of YBCO superconductor that used Solid State Reaction method, we propose the construction method using Liquid-Solid State Reaction and Self-propagating High-temperature Synthesis(SHS) method. We developed the SHS method using BaO2 and the liquid-solid state reaction method using BaO, rather than BaCO3, which using YBCO superconductor in solid state reaction method. YBCO superconductor, which was produced through presented method in the above section, using wish the XRD, we can be observed superconductor phase and inspected the superconductivity with producing wire deposition through exectrophoretic deposited, measuring critical temperature and critical current. After measurement of experiment, liquid-solid state reaction and SHS method can be proved excellent 123 phase, critical temperature, which is 92 K and 90 K can be proved better than solid state reaction method's 86 K. Critical current measured by four-probe method can be acquired 0.65 A in solid state reaction, 0.76 A in liquid-solid state reaction, and 0.73 A in SHS method. Each critical current density can be acquired 830 A/㎠, 970 A/㎠, 930 A/㎠(77 K, 0 T) by calculation.

나의주장 - "남북 화해의 새로운 시대 21세기는 한민족 과학기술로"

소대화,So, Dae-Hwa 한국과학기술단체총연합회 2001 과학과 기술 Vol.34 No.4

보조전계를 이용한 전기영동 초전도 막의 제작

소대화,전용우 한국전기전자재료학회 2003 전기전자재료학회논문지 Vol.16 No.2

For fabricating high T$\sub$c/ superconducting deposition film, novel electrophoretic deposition (EPD) technique applied to deposit surface charged particles on metal substrate with only d.c field has been studied. However, the electric properties of superconducting film could not be improved easily by this way, because the particles of EPD film were usually deposited randomly on metal substrate without any directional orientation affected to its critical current density. For the purpose of obtaining partcle orientation on the EPD films, the new method modified by a.c. assisted field to the conventional electrophoresis system was investigated to improve the particle deposition density and to increase the contacting area among the particles with highly oriented particle deposition of BSCCO superconducting film.

선박안정수의 해양외래침입생물체 처리 기술

소대화,장지도 한국정보통신학회 2003 한국정보통신학회논문지 Vol.7 No.7

The introduction of invasive marine species of living things into new environments by ship's ballast water, attached to ships' hulls and via other vectors has been identified as one of the four greatest threats to the world's oceans by Global Environment Facility(GEF). Making use of the new technology of alpha-AL$_2$O$_3$ dielectric barrier layer, the strong electric-field gas discharge was introduced and obtained between micro-gap electrodes at high pressure (∼105㎩) of $O_2$ in air and $H_2O$ in seawater. The mixed air with $H_2O$ could be ionized and dissociated into large numbers of activated particles of OH, $O_2$+, O(1D), HO$_2$ and so on, and then dissolved into the ballast water to form dissolved hydroxyl radical with the concentration of ∼20mg/L. Therefore, the invasive marine species was treated effectively through the hydroxyl radical dissolved pipeline of ballast water by strong electric -field discharge. 국제환경기구(GEF)의 해양환경 위해 지정 대상의 하나인 선박안정수 처리기술로써, 선박 안정수에 포함되어 타 지역으로부터 이동되는 유해성외래침입생물 처리방안을 제안하였다 alpha-AL$_2$O$_3$ 유전장벽층 전극에 의한 강 전리방전 기술을 적용하여 주위 산소와 물분자로부터 고농도 수산자유기(OH : hydroxyl radical) 및 활성입자( OH, $O_2$+, O (1D), HO$_2$)를 전리, 발생시켜서 이들을 해수에 신속히 용해 확산시켜 비교적 낮은 ∼20mg/L 정도의 수산기농도 하에서 유해성외래침입생물을 소멸 처리하는 환경 친화적 녹색 청정 처리기술이다. 제안된 기술은 대상물의 처리 후 부수적으로 발생할 수 있는 처리잔류물이 전혀 발생하지 않으며, 인공적 화학성분의 약제를 사용하지 않는 저렴한 처리방법으로 대ㆍ소형 원양선박의 안정수에 포함되어 있는 유해성외래침입생물의 타 지역 해양확산을 방지하고 안전하게 처리할 수 있는 자연치유적 신기술이다.

多重點火 回路의 設計 및 그 特性硏究

蘇大和 명지대학교 1984 明大論文集 Vol.15 No.-

For the strong ignition spark of the gasoline engine, the multispark ignition circuit was designed, and its ignitting voltages with respect to the variable driving pulse frequencies (1KH_z―3KH_z) and duty cycles (10%―90%) were measured by the gap-size of the discharging electrodes. The characteristics of the spark voltages for the variable engine speed were studied in comparing the conventional ignition system with the multi-spark system. With using the multi-spark ignition system, the investigated results are 1. emitting the strong multi-ignition sparks during the explosion with the constant discharging voltage for the variable engine speed. 2. protecting the chattering and arc discharge of the contact point. 3. eliminating the miss-fire on the high operating speed. 4. starting rapidly in arctic environment. 5. obtainning the possibility of the ignition-time control by the devised circuit of the variable ignition-time.

전기영동 초전도후막의 전착밀도 개선

소대화,전용우,이영매,임병제,Korobova, Natalya 명지대학교 산업기술연구소 2001 産業技術硏究所論文集 Vol.20 No.-

YBCO superconducting thick films were perpared on Ag wire by electrophoresis in acetone and ethanol with chemically modified suspension. The addition of organic compounds, such a PEG into suspension solution for improving critical current density was investigated. Surfac state, deposition conditions, pore distribution and cracks were investigated by using SEM photographs. Controlling preparation conditions were studied for reducing these defects. As a results, in acetone slolution, the surface crack of samples was decreased with increasing PEG. To develop optimum microstructures for samples processes affect the microstructure and hence the properties of ceramic superconductors.