당뇨병유발백서에서 급성패혈증 병발시 적혈구막지질과산화의 변화

박성우,홍성관,유형준,장대영,강승식,유재명,임성희,최문기,노정우,이규만 대한당뇨병학회 1994 Diabetes and Metabolism Journal Vol.18 No.3

무가압 침투법에 의해 제조된 Al/BN 복합재료의 미세조직과 인장성질

조수연,이건배,심호섭,허성우,유황룡,권훈 대한금속재료학회(대한금속학회) 2000 대한금속·재료학회지 Vol.38 No.12

Spontaneous infiltration and strengthening behaviors were analyzed in terms of microstructures and tensile properties of Al/BN composite fabricated by pressureless infiltration technique, compared with control alloy without BN fabricated by the same method. The Mg₃N₂ formed by the reaction of Mg vapor and nitrogen gas, which coated the particles in the powder bed, is believed to induce spontaneous infiltration through a great enhancement of wetting via the following reaction, Mg₃N₂+ 2Al→2AlN + 3Mg. This was identified by the finding of AlN particle layers on the surfaces of old Al particles in the powder bed, which contacted with the infiltrating melt. In addition, unreacted Mg₃N₂ was observed outside the composite, where the Al melt directly did not come into contact. Fine AlN particles formed in-situ resulted in a significant strengthening even in the control alloy with no addition of BN. In the composite reinforced with BN, additional AlN was formed by the interfacial reaction of the BN and Al melt as well as AlN by the in-situ reaction. Consequently, both the BN particles and the additional AlN particles formed by the interfacial reaction led to a further strengthening in the composite, as compared to control alloy strengthened by the AlN particles formed in-situ.

Ti(4) 및 Fe(3) 이온을 함유한 황산 수용액중에서 D2EHPA 에 의한 용매추출에 관한 연구

신영훈,유영홍,이철태,김재용,유정근 고려대학교 공학기술연구소 1991 고려대학교 생산기술연구소 생기연논문집 Vol.27 No.1

This study was carried out to find fundamental conditions for effective solvent extraction of Ti and Fe components from leaching solution of reaction product of (NH₄)₂SO₄ and titaniferous magnetite ore. In experiment of solvent extraction of Ti and Fe components, new aqueous phase which contains only Ti(IV), Fe(III) was used instead of leaching solution of sulfation product. The extraction of Ti(IV) and Fe(III) components from aqueous phase with D₂EHPA (Di-2-ethyl hexyl phosphoric acid)-kerosine system was carried out as function of concentration of extractant in the organic phase, pH of agueous phase and shaking time. The maximum value of separation factor(β) was 102.6 at 0.05 M D₂EHPA, aqueous phase pH 1.0, and 30 min was sufficient for the condition of shaking time. In stripping of Ti and Fe components from organic phase; the higher temperature and more concentration of H₂SO₄ increased the stripping percent of Ti and Fe components and the stripping percent of Fe was always higher than that of Ti. In separation process of Ti and Fe components, when 2 step stripping process was used, 93.7%, 99.5% Ti and Fe components was obtained respectively. While, 3 stage continuous countercurrent process was used, 96.3%, 84.7% of Ti and Fe components was obtained respectively.

황산암모늄에 의한 철산화물의 황산화반응

유영홍,이철태,박용성,홍상의 고려대학교 공학기술연구소 1986 고려대학교 생산기술연구소 생기연논문집 Vol.22 No.1

The reactions between iron oxides, such as α-hematite, magnetite and wuestite with ammonium sulfate were investigated in order to find the possibility of (NH₄)₂SO₄ being a sulfating agent and a new selective separation process of Fe component from natural ore. In these reactions, iron oxides were converted to (NH₄)₃Fe(SO₄)₃ or(NH₄)Fe(SO₄)₂ under various experimental conditions. In proportion to the increase of (NH₄)₂SO₄ mole ratio to iron oxide, the conversion ratio were increased. With an increased reaction temperature, the reaction rate and conversion ratio were increased. Under N₂ gas flow rate = 30㎤/min, reaction time = 3h, the optimum reaction temperature was 350℃ for all iron oxides, and the optimum (NH₄)₂SO₄ mole ratio to the iron oxide were 10.0 for α-Fe₂O₃, 21.0 for Fe₃O₄ and 5.0 for FeO, respectively. Under above mentioned conditions, the conversion of iron oxide to ammonium iron sulfate were 97.31% for α-Fe₂O₃3, 94.33% for Fe₃O₄ and 95.41% for FeO, respectively.

염화암모늄에 의한 ilmenite 의 염소화반응

유영홍,이철태,박용성,김재용 고려대학교 공학기술연구소 1985 고려대학교 생산기술연구소 생기연논문집 Vol.21 No.1

The reactions between raw ilmenite and NH₄Cl, and between alkali(NaOH) fritted ilmenite and NH₄Cl, were experimentally investigated in order to find the possibility of NH₄Cl, being an alternative chlorine source. By comparing the experimental results, NH₄Cl, was a good alternative chlorine source for the chlorination of alkali frilled ilmenite. The optimum conditions for alkali fritting were caustic ratio: 1.0, fritting temp.: 800℃, holding time : Ih and for the chlorination of alkali frilled ilmenite were reaction temp. : 325℃, weignt ratio of NH₄Cl, to ilmenite: 5.0, reaction time : Ih, N₂ gas flow rate : 30 ㎤/min. Under above mentioned conditions, the conversion of iron in ilmenite to iron chloride was 88.9% and the content of TiO₂ increased from 55.5% to 88.3%.

후판 표면 산화층 색상에 미치는 산화층의 표면 현상 및 상분율의 영향

박신화,유경종,이중주,홍순태,손병준 대한금속재료학회(대한금속학회) 2001 대한금속·재료학회지 Vol.39 No.10

It was known that the color of Hematite(Fe₂O₃) is red, while Magnetite(Fe₃O₄) is dark blue. To clarify the origin of red color on the steel plate, the relationship between the volume fraction of oxide phases and the color of steel plate was investigated in this study. The volume fraction of Wu¨stite, Magnetite, and Hematite was quantitatively evaluated by a direct comparison X-ray method using crystal structure informations. Furthermore, the effect of volume fraction and the manufacturing process on the surface color of steel plate was investigated. It was found that FRT(final rolling temperature) played an important role on the plate color.

당뇨병(糖尿病)의 식사요법

유형준,송오금 대한당뇨병학회 1985 Diabetes and Metabolism Journal Vol.9 No.1

자가혈당검사를 수행하는 당뇨병 환자의 자기조절행위에 관한 조사연구

구미옥,유주화,엄동춘 대한당뇨병학회 1994 Diabetes and Metabolism Journal Vol.18 No.3

MgO 와 NH4Cl 의 반응을 이용한 Mg 성분추출 및 암모니아의 회수

김원배,유영홍,이건직 고려대학교 공학기술연구소 1990 고려대학교 생산기술연구소 생기연논문집 Vol.26 No.1

Reaction of MgO with NH₄Cl was investigated in order to find the fundamental data for a new extraction process of magnesium component from MgO and to recover NH₃(g) from NH₄Cl Reaction mechanisms of MgO with NH₄Cl were as follows: Reaction temperature; 225℃ - 250℃ i) MgO + 3NH₄Cl ― NH₄MgCl₃ + H₂O + 2NH₃ Reaction temperature; over 300℃ ii) 2MgO+NH₄Cl+H₂O ― Mg₂(OH)₃Cl+NH₃ iii) Mg₂(OH)₃Cl+NH₄MgCl₃ ― 3MgOHCl+NH₄Cl iv) MgO+NH₄Cl ― MgOHCl+NH₃ v) MgOHCl+NH₄Cl ― MgCl₂+NH₃+H₂O vi) MgO+2NH₄Cl ― MgCl₂+2NH₃+H₂O The optimum conditions of extraction of magnesium were as follows: Reaction time 15 min Reaction temperature 350℃ Mole ratio of NH₄Cl to MgO 4.0 N₂ gas flow rate 30 ㎤/min Under these conditions, the extraction of magnesium was 99.99% and the recovery of NH₃(g) was 81.69%. For the recovery of NH₃ Reaction time 1h Reaction temperature 400℃ Mole ratio of NH₄Cl to MgO 4.0 N₂ gas flow rate 30 ㎤min Under these conditions, the recovery of NH₃ was 93.33%.

α형 스터링 엔진의 최적 설계 조건

강문규,이택희,유재환 한국산업안전학회 1998 한국안전학회지 Vol.13 No.4

A stirling engine is a mechanism used to convert heat to power and operates on a closed regenerative thermodynamic cycle with compression and expansion of the working fluid at different temperature. The performance of a stirling cycle machine is a function of six independent parameters, namely; ① speed N(r.p.m), ② pressure of the working fluid p(Pa), ③ ratio of the temperature in the compression and expansion space r (=T_C/T_E), ④ ratio of the swept volumes in these two spaces K, ⑤ phase angle α and ⑥ dead volume ratio X. This paper describes the procedure and presents the results of computations carried out to establish the optimum combinations of these six parameters for maximum engine output for the machine acting as a prime mover, over a combined temperature range from 300˚ K to 1000˚ K and dead volume ratio X ranging from 0.1 to 2.0. The output of a stirling cycle machine can be expressed in terms of nondimensional power in several different ways. Four methods were studied in detail, the parameters optimized and design charts and engine power charts prepared. The results of this paper may be useful as a guide to the likely effects on the performance of some of the important design parameters and regenerator design.