방전 플라스마에 의한 CFC-12(CCl2F2)의 분해

황명환,우인성,조정국,강현춘,안형환,이한섭,강안수 한국산업안전학회 1999 한국안전학회지 Vol.14 No.3

Decomposition efficiency, power consumption, and applied voltage of CFC(Chlorofluorocarbon) were investigated by SPCY(surface induced discharge plasma chemical processing) reactor to obtain optimum process variables and maximum decomposition efficiencies. Decomposition efficiency of CFC-12 with various electric frequencies(5∼50㎑). flow rates (100∼1,000mL/min), initial concentrations(100∼1,000ppm), electrode materials(W, Cu. Al), electrode thickness(1, 2, 3mm) and reference gases(N₂, O₂, air) were measured and the products were analyzed with FT-IR. Experimental results showed that at the frequency of 10kHz, the highest decomposition efficiency of 92.7% for CFC-12 were observed at the power consumptions of 29.6W, respectively, and that decomposition efficiency decreased with increasing frequency above 20㎑ and decomposition efficiency per unit power were 3.13%/W for CFC-12. Decomposition efficiency was increased with increasing residence times and with decreasing initial concentration of pollutants. Decomposition efficiency was increased with increasing thickness of discharge electrode and the highest decomposition efficiency was obtained for the electrode diameter of 3mm. As the electrode material, decomposition efficiency was in order that tungsten(W), copper(Cu), aluminum (Al).

제왕절개수술에서 저혈압 예방을 위한 수액의 비교 관찰 : 제 1 보:척수마취

심재철,김완식,박동호,황영희,김흥대,김지영,차영덕,서병태 대한마취과학회 1982 Korean Journal of Anesthesiology Vol.15 No.3

Rheomacrodex-D 10% W/V in dextrose (500 ml) was prophylactically infused before anesthesia over 15 to 20 minutes to prevent hypotension during spinal anesthesia in 20 patients undergoing elective Casarean section. Apgar scores and the incidence and severity of hypotension were compared to results obtained in 20 patients who were given 500 ml of Hartmann's solution. The results were as follows; 1) Mean arterial pressure decreased up to 20 torr from control values in patients hydrated with Hartman's solution and also changed significantly in patients given Rheomacrodex-D (p<0.05). 2) The incidence and severity of hypotension at 10 minutes, and 15 minutes, and 15 minutes after spinal anesthesia (p<0.05) was significantly less in patients given Rheomacrodex-D than in patients hydrated with Hartmann's solution 3) The Apgar scores, both at 1 minute and 5 minutes, were significantly higher (p<0.05, p<0.005) in infants born of mothers given Rheomacrodex-D than in infants whose mothers were given Hartmann's solution. 4) The cases of hypotension defined as a descrease in systolic arterial pressure lower than 100 torr or a decrease in mean arterial pressure to 25% from control values were 12 cases in 20 patients hydrated with Hartmann's solution and 6 cases in 20 patients given Rheomacrodex-D.

급성췌장염에 의한 췌장가성남종에서 내시경적 배액술후 발생한 췌장가성남종과 십이지장 및 대장에 발생한 내부 췌장루 1예

김연수,이문성,김진오,조영덕,이영홍,봉형근,조주영,이준성,심찬섭,황성규,전기원,변재호,장재영 대한소화기학회 1996 대한소화기학회지 Vol.28 No.1

보행마취(步行麻醉)

김영석,김완식,황호성,이진근,유희구,김흥대 대한마취과학회 1977 Korean Journal of Anesthesiology Vol.10 No.2

An imaginative innovation to shorten hospital stays as a means to reduce patient charges, is out-patient surgery. This procedure also minimized the inconvenience and disruption of the family unit, reduced the opportunities for cross-infection, and freed hospifal beds for the more serriously ill patienta Since the concept of out-patient surgical service was organized, managed, and performed in the Hanyang Medieal Center, we had experience of 132 ambulatory anesthetics during the last two years (from Jan. 1974. to Dec. 1975 ). The results are summarized as follower 1. Preanesthetic examination should be routinely cheeked with Hb., Hct., urinalysis and chest x-ray. 2. Premedication should be administered preanesthetically, atropine sulfate intravenously. 3. ASA class 1 patients should be rhnsen fnr short (less than 1 hour) procedures. 4. Anesthesia is induced with Epontol+S.C.C. and maintained with Halothane+N2O+O2. 5. We suggest that ambulatory anesthesia should be more carefully planned, organized, and managed.

진동형 분진 최소착화에너지측정장치에서 분진 응집현상이 미치는 영향

정재희,최충석,목연수,최광석,황명환,우인성,Yamaguma, M.,Kodama, T.,Cheung, W.L. 한국산업안전학회 1999 한국안전학회지 Vol.14 No.3

It is widely recognized that Hartmann tube for measuring the minimum ignition energy(MIE) of powder. But It requires long time and operational skills for measuring. As a variety of new fine powders are being produced day by day in industry, Japen has been developing a measurement system which employs a new method to create a dust/air mixture in a miniature combustion box. In this system, by vibration, the powder is successively fed downward through a hopper made up of metal mesh, and then it is formed into a thin, certain-like, dust/air mixture. With this new apparatus, three types of powder-Lycopodium, Anthraquinone, and Polyacrylonitrile-were tested and the data of MIE were compared with those of a conventional apparatus (the Hartmann tube). Two of them agreed satisfactory, but the other, Anthraquinone, showed quite different values. It is guessed that the agglomerations of the powder particles appear because of particle shapes, static-charge and humidity.

Sbi3 를 첨가한 25% Bi2Te3-75% Sb2Te3 와 15% Bi2Te3-85% Sb2Te3 단결정의 전기적특성과 열전특성

현도빈,황종승,심재동,오태성,하헌필 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.8

The temperature dependences of the electrical and thermoelectric properties of the SbI₃-doped 25% Bi₂Te₃-75% Sb₂Te₃ and 15% Bi₂Te₃-85% Sb₂Te₃ single crystals, grown by the Bridgman method, were measured at temperatures ranging from 77 K to 600 K. For the Sb₂Te₃-rich single crystals, the temperature dependence of the Hall mobility was T^(-1.0) regardless the Sb₂Te₃ contents and added amount of SbI₃. The temperature dependences of (m*/m_o)^(3/2)·μ_c and effective mass m*/m_o were T^(-1.5) and T^(-1/3), respectively. The decrease of the saturated hole concentration and the change of the slope of the Seebeck coefficient with temperature were considered in the view point of the two sub-bands in the valence band. The maximum figure-of-merit at 300 K of 0.2 wt% SbI₃-doped 25% Bi₂Te₃-75% Sb₂Te₃ and 0.4 wt% SbI₃-doped 15% Bi₂Te₃-85% Sb₂Te₃ single crystals were 2.25×10^(-3)/K and 1.95×10^(-3)/K, respectively.

폭발합성법에 의한 Ti5Si3 계 금속간화합물의 합성

강봉용,황선근,류회수,김상우 대한금속재료학회(대한금속학회) 1998 대한금속·재료학회지 Vol.36 No.10

Synthesis of an intermetallic compound based on Ti_5Si₃ by an explosive compaction of elemental powders was studied. The main experimental variable was the detonation velocity, and it was found that the relative density of the compacted compound increased with the detonation velocity. To enhance the density of the compound further, however, it was deemed necessary to consider variables such as the can, powder and the backup tube. From an X-ray diffraction analysis of the explosion-compacted compound it was confirmed that formation of the Ti_5Si₃ phase was complete. Apart from the needs to further improve the density and crack resistance of the compacted alloy, the present work indicates that the explosion synthesis has a potential to be developed as a consolidation method for Ti_5Si₃ intermetallic compounds.

반추동물에서 분리한 혐기성 곰팡이의 성장지표간의 상관관계

김홍대,하종규,황일환,심성수 한국영양사료학회 1999 韓國營養飼料學會誌 Vol.23 No.3

본 시험은 반추위 곰팡이의 성장 지표를 다양한 방법으로 측정하고, 이들과 실제 곰팡이 biomass와의 상관관계를 살펴봄으로써, 혐기성 곰팡이의 성장을 추정할 수 있는 효율적 방법을 검토하고자 수행되었다. 시험에 사용된 균주는 Neocallimastix frontalis C5-1, Piromyces sp. PH-2, Orpinomyces sp. OH-4로서 한우와 Holstein 젖소에서 분리된 것이며, 2, 4, 6일 배양후, gas production, pH를 측정하고, 원심분리 후 상층액증의 acetate 및 total carbon를 측정하였으며, 곰팡이 균체를 수거하여 freezed dryweight 및 fungal protein과 chitin을 측정하고, 주요 성장 지표간의 상관관계 (correlation coeffciency)를 검토하였다. 배양시간에 따른 반추위 곰팡이의 biomass와 성장 지표의 측정결과는 다음과 같다. 반추위 곰팡이의 동결 건조무게는, Neocallimastix frontalis C5-1, Piromyces sp. PH-2는 배양 4일까지는 증가하다가 6일째 측정시 감소하였으나, Orpinomyces sp. OH-4는 계속하여 증가하였다. 배양액의 pH 값은 배양시간에 따라 감소하다가 배양 4일 이후부터는 증가하였으며, 곰팡이가 active growth stage에 있을 때 DM과 역의 상관관계가 있었다. Gas production의 경우 균주에 따른 생산량의 차이가 있었으나, 배양일에 따라 증가하였으며, 곰팡이가 active growth stage에 있을 때 DM과 높은 상관관계가 있었다. 최종 발효대사산물인 acetate의 배양액중의 함량은 배양 4일까지 증가하다가 감소하는 경향을 보였으며, 균주에 따른 차이는 있었으나 DM과 상관관계가 있었다. 그리고 fungal protein과 chitin은 곰팡이의 DM과 높은 상관관계를 나타냈으며, protein과 chitin간에도 높은 상관관계를 나타냈다. 한편, 배양액중의 total carbon의 경우 균주에 관계없이 감소하는 경향을 나타냈으며, 역의 상관관계가 있는 것으로 나타났다. 결론적으로 균주에 따라 차이는 있었지만, 조사된 곰팡이 성장지표들 중에서 배양액의 pH total cabon과 acetate의 농도, 그리고 gas production과 균체 단백질 등이 곰팡이의 건물무게와 상관관계가 높았던 것으로 조사되었다. This study was conducted to find out effective methods for estimating fungal growth by comparing various growth indicators of anaerobic rumen fungi with fungal biomass in vitro. Three different strains of ruminal fungi(Neocallimastix frontalis C5-1, Piromyces sp. PH-2, Orpinomyces sp. OH-4) were isolated from Korean native cow and Holstein dairy cow. Lysophilized dry matter, acetate, total carbon, fungal protein and chitin were determined after 2, 4, 6 days of incubation. Gas production and pH value were determined after 2, 3, 4, 5, 6 days of incubation in Lowe's medium. Fungal biomass of Neocallimastix frontalis C5-1 or Piromyces sp. PH-2 was increased during the initial 4 days of incubation, and thereafter the biomass was decreased by autolysis. On the other hand, fungal biomass of Orpinomyces sp. OH-4 was continuously increased up to 6 day incubation. There was a negative correlation between pH value and fungal dry weight during the active growth stage. The pH values of three different fungi were significantly decreased with the incubation time, but increased after 5 day incubation. Cummulative gas production was somewhat variable among fungal strains, but increased throughout the incubation period. There was a high correlation between cummulative gas production and dry matter (DM) during active growth stage. Changes in acetate concentration of the medium showed a similar pattern to that of fungal dry weight by incubation time. The fungal dry weight of OH-4 was increased during all incubation time but the acetate concentration of Orpinomyces sp. OH-4 was decreased after 4 day incubation. There was a positive correlation between acetate concentration and DM. The fungal protein was found to be a reliable indicator of fungal growth during all incubation days. Total carbon in the medium was decreased regardless of fungal strains and had a high negative correlation with DM during the active growth stage.

SbI3 를 첨가한 33.3 % Bi2Te3-66.7 % Sb2Te3 열전반도체의 전기적특성과 열전특성

현도빈,황종승,심재동,오태성,황창원 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.2

The temperature dependences of the electrical and thermoelectric properties of the SbI₃-doped 33.3% Bi₂Te₃66.7% Sb₂Te₃ single crystals have been measured at temperatures ranging from 77K to 600K. The scattering parameter of the 33.3 Bi₂Te₃-66.7% Sb₂Te₃ single crystals was determined as s = 0. With increasing the amount of SbI₃ dopant, the hole concentration of the 33.3% Bi₂Te₃-66,7% Sb₂Te₃ single crystal is decreased, resulting in the increment of the Seebeck coefficient and electrical resistivity, and the temperature for the maximum figure-of-merit shifted to lower temperature. A maximum figure-of-merit of 2.3×10^(-3)/K was obtained for 0.3 wt% SbI₃-doped specimen. It has been revealed that. the addition of SbI₃ as a donor dopant is useful in controlling the hole concentration of p-type 33.3% Bi₂Te₃ 66.7% Sb₂Te₃ alloy system.

화재완화를 위한 소듐 루프 건물의 구획화

김병호,권상운,정경채,김광락,황성태 한국산업안전학회 1998 한국안전학회지 Vol.13 No.3

Analysis on the study for the sodium fire mitigation was carried out using the CONTAIN-LMR code. Sodium loop building was partitioned into the many cells, in which the safety venting systems were installed for the purpose of improving the sodium fire safety and minimizing its effect on the sodium loop building. The effects of sodium fire on sodium loop building partitioned into the many cells and not partitioned were investigated. The peak pressure and temperature of each cell accompanied by sodium fire in sodium loop building partitioned were lower than those of sodium loop building not partitioned. In the case of partitioning sodium loop building, the pressures, temperatures and aerosols into cells were transferred through propagation path of CONTAIN-LMR sodium fire model simulated by this study, and the effect of sodium spray fire on sodium loop building was mitigated by partitioning building. In addition, the excessive rise of pressure into cells was prevented by installing the over-pressure exhaust valve and under-pressure exhaust valve on the flow path between cells.