고온에서 HAN 계열 추진제 액적의 거동에 대한 연구

황창환(Chang Hwan Hwang),백승욱(Seung Wook Baek),한조영(Cho Young Han),김수겸(Su Kyum Kim),전형열(Hyung Yeol Jeon) 한국연소학회 2012 KOSCOSYMPOSIUM논문집 Vol.- No.45

The droplet behavior of 83.9 wt.% HAN water solution was investigated experimentally with various ambient temperature and nitrogen environment. At the initial stage of evaporation under thermal decomposition temperature of HAN, gradual decreasing of droplet diameter was observed. After that, the droplet started to expand due to the internal pressure build up by water nucleation inside the droplet. The micro explosion was observed at higher temperature than the decomposition temperature of HAN and the remaining droplet showed similar behavior of single composition droplet. The decreasing rate was augmented as the ambient temperature increasing.

신라대학교 주변 백양산의 동물상

노치권(외 6명) 신라대학교 자연과학연구소 2012 自然科學論文集 Vol.22 No.-

To study fauna of Silla University located in Mt. Baek-yang, we conducted six surveys from 29 May 2011 to 28 April 2012. We found five phyla 41 orders 197 species of animals inhabiting in this area: four phyla 27 orders 163 species of invertebrates and in vertebrates one order six species of fishes, three orders nine species of amphibians and reptiles, six orders 14 species of aves, and four orders five species of mammals. Of these species, some Korean endemic species were included: a fish of Rhodeus uyekii in a pond near main gate of this university, a frog of Rana coreana in a creek near a dormitory, and a rabbit of Lepus coreanus and a water deer of Hydropotes inermis in a grass region near a main stadium. A kind of hawk, Falco tinnunculus as a natural monument (animal) of no. 323-8, was observed on a building of medical and life science. A blue frog of Hyla japonica as a variation was found near a spring resort. Therefore, this area is considered an ecologically important area having a high animal diversity.

甘草의 有效性分 含量에 關한 硏究

韓宗鉉,白承和,康成溶,宋昊埈 한국전통의학연구소 1997 한국전통의학지 Vol.7 No.2

시중에 유통되고 있는 4종류의 감초(특감초,원감초,일호감초,이호감초)에 대하여 유효약리성분 glycyrrhizin, 18α-glycyrrhetinic acid 및 glycyrrhizic ammonium salt의 함량을 대한약전의 규격기준에 준하여 검토한 결과는 다음과 같았다. 1. 감초의 수분함량은 7.00-10.16%범위 였다. 2. 감초의 회분 및 산불용성 회분 함량은 3.03-4.09%, 0.02-0.11 % 범위 였다. 3. 감초 품질의 지표성분인 glycyrrhizin,18α-glycyrrhetinic acid 및 glycyrrhizic ammonium sait 을 TLC로 각각 Rt값 0.399,0.932,0.394 위치에서 암자색의 반점을 확인할 수 있었는데 특 감초,원 감초,1호 감초,2호 감초 모두 같은 위치에서 뚜렷한 암자색 반점을 확인할 수 있었고,확인되지 않은 3종 화합 물의 Rt 값은 0.28,0.66,0.78 였다. 4. 감초품질의 지표성분인 glycyrrhizin,18 α-glycyrrhetinic acid 및 glycyrrhizic ammonium salt을 HPLC로 정량한 결과 glycyrrhizin은 4종류 감초에서 분석되어 2.93-4.48g% 범위였고, 18 α-glycyrrhetinic acid는 특감초 및 일호감초에서만 13.64,3.52 g% 함유되었다. 그러나 glycyrrhizic ammonium salt 분석되지 않았다. 5. 문헌상에 기록된 감초의 종류는 16종이었고 이들에서 분리된 화학물질은 약 170여 가지였다. This study was carried out to investigate the content of glycyrrhizin, 18 α-glycyrrhetinic acid, glycyrrhizic ammonium salt, moisture, ash, residue ash in four kinds(teuk-gamcho, won-gamcho, IIho-gamcho, Eho-gamcho) in Glycyrrhizae Radix(Glycyrrhiza sp.) used in Korea. The result were as follows ; The moisture content in four kinds of gamcho was ranged from 7.00-10.16%. The ash and ash of acid residue in all gamcho types ranged from 3.03-4.09% and from 0.02-0.11 %, respectivly. The glycyrrhizin, 18 α-glycyrrhetinic acid, glycyrrhizic ammonium salt in Teuk-gamcho, Won-gamcho, IIhogamcho, Eho-gamcho verified from line of dark purplue color by TLC and Rf value of glycyrrhizin, 18 α-glycyrrhetinic acid, glycyrrhizic ammonium salt were 0.399, 0.932, O. 394, respectivly, and the Rf value unknown compoud were 0.28, 0.66, 0.78. The glycyrrhizin, 18 α-glycyrrhetinic acid, glycyrrhizic ammonium salt content of all gamcho by HPLC were ranged from 2.93-4.48g%, 3.52-13.64g%, and trace, respectively. The 16 kinds of Glycyrrhiza (Licorice) were dassified, and that the identification about 170 chemicals were phamacology action substrate by reported references.

허혈 조건부여가 심근기능의 회복에 미치는 영향 : 적출 심장모델을 이용한 실험연구 Isolated heart experimental study

백광제,김준식,한승백,전영진,이인성 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Background: Brief episode of coronary artery occlusion(i.e.,ischemic preconditioning) makes the heart more resistant to injury from a subsequent ischemic insult. Although a great deal of effort has been made in studying ischemic preconditioning, the underlying mechanism of ischemic preconditioning and its effect on hypothermic insult has not been elucidated. This study was performed to see whether ischemic preconditioning protects against the depression of cardiac contractility induced by hypothermic cardioplegic arrest/reperfusion. And recently, adenosine was known to have some correlation with the mechanism of preconditioning. If so, does this effect remain after the blockade of adenosine receptor by 8-phenyl theophyline? Method: Twenty-four Sprague-Dawley rat weighed 250-350g were used and divided into three groups. Rat hearts were removed rapidly, and each isolated heart paced with a rate of 180/min was perfused by modified Krebs-Hensleit buffer(KHB) solution on a Langendorff apparatus for an hour. After obtaining baseline data including left ventricular pressure(LVP), dp/dt, and coronary flow, cardiac arrest was induced by perfusion of 0℃ crystalloid cardioplegic(St Thomas) solution. After that, all hearts were stored in the same St Thomas solution at same temperature for 2 hours. In group Ⅰ(control group), the heart was reperfused by KHB solution. In group Ⅱ(preconditioning group), the heart was subjected to two 2-minute episode of global ischemia followed by 5 minute reperfusion with KHB solution(preconditioning) before cardiac arrest. In group Ⅲ(phenyl theophylline group), the heart was subjected to preconditioning procedure and 8-phenyl theophylline at 10μM in concentration was added to KHB solution at time of reperfusion. Observing parameter was obtained in each group at 10, 20, 40 and 60 minutes after starting reperfusion and compared statistically by use of one way ANOVA test(STASTICA, release 4.5). p-value less than 0.05 was considered significant. Results: Although depressed LVP, dp/dt, and coronary flow were seen in all groups during the reperfusion period, the preconditioned group showed more effective recovery of LVP than that of the control group, especially at 10, 20 and 40 minutes(p<.05). We failed to demonstrate the difference between the phenyl theophylline group and the control group(p=NS). Conclusion: These results suggest that ischemic preconditioning has protective effect on recovery state of hypothemic cardioplegic arrest/reperfusion. Its protective effect was limited during early reperfusion stage and was blocked by adenosine blocker.

울산연안 定置網에 어획된 漁類의 종조성 및 양적변동

한경호,김종헌,백승록 한국어류학회 2002 韓國魚類學會誌 Vol.14 No.1

울산 정자연안 외측에 위치한 정치망에서 1998년 2월, 4월 ,6월 ,8월 10월 및 12월, 총 6회에 걸쳐 어획물을 채집하여, 魚類의 種組成, 量的變動 및 群集構造에 대하여 연구하였다. 채집된 어류는 총 12目 45科 89種, 62,978개체였고, 총 생체량은 6,494㎏이였다. 농어目 어류와 쏨뱅이目 어류가 총 56種으로 전체 出現種數의 62.9%를 차지하여 가장 우점하는 目들로 나타났으며, 科別로는 전갱이科와 참복科 어류가 각각 7種 出現하여 가장 많은 種이 出現하였다. 총 89種의 어류중 個體數는 고등어, 전갱이, 멸치 및 말쥐치의 4種이 全個體數의 89.7%를 차지하여 우점하였다. 生體量은 고등어, 전갱이, 꽁치, 말쥐치, 전어, 꼬치고기, 멸치, 정어리, 임연수어 및 덕대의 順으로 이들 10種이 全生體量의 95.5%를 차지하여 우점하였다. 出現 個體數와 生體量은 고수온기인 여름에 높게 나타났으며, 저수온기인 봄과 겨울에 낮게 나타나 수온과 밀접한 관계가 있었다. 월별 出現種數는 2월과 10월에 비교적 적은 種이 출현하였으며, 4월에 49種, 6월에 50種이 나타나 가장 많은 種이 출현하였고, 8월에 46種, 12월에 44種이 出現하였다. 종다양도지수(H')와 0.693~2.146으로 4월에 가장 높은 값을 보였고, 8월에 가장 낮은 값을 보였으며, 우점도지수는 다양도지수와 반대로 4월에 가장 낮은 값을 8월에 가장 높았다. 주요 魚種의 出現頻度를 보면 고등어, 전갱아. 멸치, 말쥐치, 꽁치, 전어, 망상어 및 정어리가 거의 年中 出現하여 본 해역에서의 주거종이었다. Fishes were collected by set net to determine seasonal species composition and fluctuation in abundance in coastal waters of Ulan. Korea, in February, April, June, August and December, 1998. A total of 62,978 fishes (6,494㎏) were sampled and classified into 12 orders, 45 families and 89 species. The most dominant orders were Perciformes and Scorpaeniformes, which accounted for 62.9% of the total. The most dominant families were Carangidae and Tetraodontidae, each represented seven species. The most dominant species were Scomber japonicus, Trachurus japonicus, Engraulis japonicus and Maurolicus muelleri, which accounted for 89.7% of the total fishes collected. The most dominant in biomass were Scomber japonicus, Trachurus japonicus, Cololabis saira, Thamnaconus modestus, Konosirus punctatus, Sphyraena pingues, Engraulis japonicus, Sardinops melanostictus, Pleurogrammus azonus and Pampus echinogaster. Those species together accounted for 95.5% of the total biomass. The number of individuals and the biomass were much higher in summer than in spring and winter, and closely correlated with water temperature. The number of species showed a peak in August, with 46 species, and the lowest number in February, with 30 species. The diversity index was the highest in April(H'=2.146) and the lowest in August(H'=0.693).

구강상피세포의 냉동보관 방법에 따른 세포생존률 비교

백도영,이승종,정한성,김의성 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.6

본 연구의 목적은 구강상피세포를 배양한후 각기 다른 조건의 냉동 보존법으로 6일간 보존시 각각의 세포의 활성도를 Cell counting, WST-1, Clonogenic capacity의 방법을 이용하여 비교 평가하기 위함이다. 각 실험군당 1×10^(6)개의 세포를 다음의 방법으로 6일간 냉동 보존한다. Freezing container에 담아 1℃/min의 냉동속도로 까지 냉동 후 -196℃에 냉동하여 보관한 일반 냉동 보존군, 세포를 바로 -196℃의 액화질소에 넣어 냉동한 급속 냉동 보존군, 4℃에서 -35℃까지 -0.5℃/min속도로 서서히 냉동시킨 뒤 -196℃에 냉동한 저속 냉동 보존군, 2 Mpa, 3 Mpa의 압력을 가하고 -0.5℃/min속도로 4℃에서 -35℃까지 서서히 냉동시킨 뒤 -196℃에 냉동한 2 Mpa, 3 Mpa압력 저속 냉동 보존군으로 나누었다. 6일 후 냉동되었던 세포를 급속 해빙하여 각각의 Cell counting, WST-1, Clonogenic capacity 값을 측정하여 비교하였다. 실험 결과 2 Mpa혹은 3 Mpa의 압력을 이용한 저속 냉동법이 저속 냉동법 및 급속 냉동법 보다 세포 활성도에 있어 우수한 경향을 나타내었다. This study examined the influence of the storage methods on the viability of oral epithelial cells using conventional cell freezing storage, slow freezing preservation, rapid freezing preservation, and slow freezing preservation with a pressure of 2 Mpa or 3 Mpa. The cell viability was evaluated by cell counting, WST-1 and the clonogenic capacity after 6 days of freezing storage. After 6 days, the frozen cells were thawed rapidly, and the cell counting. WST-1, and clonogenic capacity values were measured and compared. 1. The results from cell counting demonstrated that conventional cryopreservation, slow freezing under a 2 Mpa pressure and slow freezing under a 3 Mpa pressure showed significantly higher values than slow freezing preservation and rapid freezing preservation (p < 0.05). 2. The results from the optical density by WST-1 demonstrated that slow freezing under a 2 Mpa pressure showed significantly higher values than slow freezing preservation and rapid freezing preservation (p<0.05). 3. The clonogenic capacity demonstrated that slow freezing under a 2 Mpa pressure showed significantly higher values than slow freezing preservation and rapid freezing preservation (p < 0.05).

금은화 추출물의 세포독성에 관한 연구

한종현,백승화,김일광,한두석 圓光大學校 韓醫學硏究所 1993 원광한의학 Vol.3 No.1

In order to investigate the cytotoxicity of Lonicerae Flos extract, their extracts were dissolved in distilled water and methanol. All material diluted from 10^-3to 10^-7(㎎/㎖) with distilled water putted in each well of 24 multidish cultured rat fibroblast for 48hours. The cell number was calculated at 2 days and cell shape takes photographed by inverted microscope at same day. The results were as follows: 1. The rate of cell multiplication was the lowest in water extract from 10^-3 to 10^-7(㎎/㎖) concentration and the highest in ether and hexane extract at 10^-7(㎎/㎖) concentration. 2. Index of cytotoxicity was the highest with 3 score in water extract at 10^-3(㎎/㎖) concentration and the lowest with 1 score in ether, ethyl acetate or hexane extract at same concentration. 3. The degeneration of cell shape and number was the severest in water extract of 10&-4(㎎/㎖) concentration, but ether and hexane extracts in same concentration were weaker than water extract. These results indicate that the cytotoxicity of extracts by ether and hexane from same Lonicerae Flos was weaker then water extract.

싸이리스터 PWM 전류원 무효전력보상기의 동작 해석

백승택,한병문 명지대학교 대학원 1999 대학원논문집 Vol.3 No.-

This paper proposes a new reactive-power compensator composed of a thyristor current-source inverter. The compensator consists of a 6-pulse thyristor bridge, de reactor, and a commutation circuit. The commutation circuit offers the thyristor bridge to have PWM operation with minimal switching losses. The operation of proposed system was analyzed by computer simulations with EMTP and experimental works with hardware scaled-model. The proposed system would have low cost and easy expansion of operation voltage due to using the conventional thyristors.

한국산 붕어(Carassius auratus)의 초기생활사

한경호,진동수,유동재,백승록,황동식 여수대학교 2001 論文集 Vol.16 No.-

The egg development and morphological development of larvae and juveniles of crucian carp, Carassius auratus (Linnaeus) caught at Bosung River, Chollanam-do, in April to June, 1999 were investigated in the laboratory, Yosu National University. In the spawning season, the nuptial organ was appeared on the opercular region and under region of eye, pectoral fin, ventral fin and lateral line. The egg was transparent of yellowish brown color, demersal of adhesive and sperical in shape, measuring 1.49∼1.63㎜ (mean 1.57㎜, n=50) in diameter. The first hatching was occured in 75 hours 10 minutes after fertilization in water temperature 18.3∼21.7℃. Newly hatched larvae attained mean 4.28㎜ had a big yolk sac and their mouth, and anus were not opened yet. At 5 days after hatching, the larvae attained mean 5.34㎜ and the yolk sac was almost absorded. At 13 days after hatching, the larvae attained mean 7.21㎜. The caudal notocord was flexed 45°upward, and they reached post larvae stage. At 31 days after hatching, the larvae, mean 14.68㎜ in TL reached the juvenile stage with all of the fins formed with complete set of the fin rays (D. ⅩII-11∼15; A. Ⅲ-5∼6; P. 15∼16; V. 1-8).

RUS법에 의한 Micro-Crack을 가진 Ferrule의 주파수 특성 평가

백경윤,이길성,양순호,김성훈,조영재,민한기,양인영 朝鮮大學校 機械技術硏究所 2003 機械技術硏究 Vol.6 No.2

광섬유 정렬부품으로 사용되는 페롤은 극히 높은 정밀도를 요하는 제품으로서, 높은 치수 정밀도와 결함이 포함되지 않는 등 높은 신뢰성이 요구되는 제품이다. 이러한 페롤의 형상결함평가에 종래의 광학현미경 평가법과는 달리. 본 논문에서는 공명초음파법(ResonantUltrasound Spectroscopy)을 이용하고자 한다. 공명초음파법이란 결함이 없는 시험편을 기계적으로 진동시켰을 때의 공진 주파수와 시험편 내에 결함을 가지고 있을 때의 공명 주파수 양상을 비교 분석하여 결함유무를 검출해내는 방법이다. 본 연구에서는 양품과 크랙을 가진 시험편을 현장에서 직접 사용되고 있는 광학현미경에 의해 분류를 한 다음, 더욱 정확한 측정을 위해 SEM에 의해 다시 분류하였다. 각각에 대해 공진 주파수를 측정하였고, 이 데이터의 검증을 위해 FEM해석을 수행하였다. 실험으로부터 얻는 양품의 공진 주파수와 FEM해석을 통해 얻었던 양품의 공진 주파수의 오차는 1∼2%정도의 범위를 벗어나지 않음을 알 수 있었다. 또한 크랙에 대한 공진 주파수를 측정하여서, 양품의 공진 주파수와 비교를 행하였고, 이 데이터를 가지고 모드별로 히스토그램을 그려서, 그것으로부터 현장에서 실제로 이용 가능한 모드를 존재함을 확인하였다. The Ferrule which is used as the product optical fiber very precisely, is required high to set the optical axes of an dimensional precision, lack of defect and high expectation. Up to now the optical instrument has been used for the defect and shape inspection of the Ferrule, but in this paper we examined the detectable defect and expectation by using the Resonant Ultrasound Spectroscopy (RUS). The RUS is the measurement' which is to excite specimen and to inspect the difference of natural frequency pattern between acceptable specimen and specimen has some defects. In this paper, we classified specimens into three groups by using She optical instrument; acceptable specimen A-type, 3-type and specimen A-type which has crack. And we reclassified by Scanning Microscope to carry out the more exact measurement. We surveyed the resonant frequency of every specimen, and carried out the simulation from the explicit finite elements code, NasEran t o verify the experiment data. The average error between the resonant frequency of acceptable specimens which is obtained from experiment and that from FEM analysis is in the range of 1-2 percentage. Also, we measured the resonant frequency of specimen which has crack, and compared that of acceptable specimen. We drew histogram by using these data, and confirmed the available mode in the plant.