Stearic Acid로 被覆한 Fe₃O₄에 의한 油分除去 (Ⅰ)

韓尙敏,張哲鉉,朴勝祚 동아대학교 환경문제연구소 1989 硏究報告 Vol.12 No.1

The large quantity of iron contained in waste sludge discharged form pickling liquor in a steel industry was used for Fe₃O₄. Then we new adsorbent for oil removal was made. The adsorbent was made of Fe₃O₄ coated with stearic acid. The results of this study that perform batch test to relate adsorptive ability, and oil removal efficiency of the adsorbent with kerosene, bunker-c oil, and emulsified bunker-c oil are followings : 1) The results of batch adsorption test fit well to the Freundlich equation, and the K of kerosene, bunker-c oil, and emulsified bunker-c oil was, 0.20, 0.17, and 0.16, respectively. 2) The adsorptive reaction was the first order reaction and the K' was 0.526/min. 3) The kerosene removal efficiency by new adsorbent was 30% in the alkalinity, 85% in the acidity and 92% in a neutrality.

발치 후 교정력 적용 시기에 따른 치아 이동 양상

한성호,황현식 대한치과교정학회 2000 대한치과교정학회지 Vol.30 No.1

본 연구는 발치 후 인접치 이동을 위한 교정력 적용 시 적용 시기에 따른 치아이동 양상을 비교·분석하기 위하여 시행되었다. 성견을 실험대상으로 상악 좌우 제 3절치를 3주 간격으로 각각 발거하고, 양 견치를 고정 원으로 제 2절치의 치체이동을 위한 장치를 장착하였다. 100 gm의 지속적인 힘을 내는 견인 스프링을 사용하여 발치 후 4주와 1주부터 좌우 제 2절치를 각각 12주간 동시에 견인하였다. 2주 간격으로 디지털 캘리퍼스를 이용하여 이동거리를 측정·비교하고 실험에 사용된 좌우 제 2절치의 조직소견을 관찰하여 다음과 같은 결론을 얻었다. 1.교정력 적용 후 처음 2주간에는 발치 후 4주에 견인한 치아가, 그 다음 2주간에는 발치 후 1주에 견인한 치아가 빠르게 이동하는 양상을 보였다. 2.12주간의 실험기간 동안 견인 4주와 6주 사이에 가장 빠르게 이동하는 경향을, 이 후에는 이동 속도가 감소하는 양상을 보였다. 3.실험기간 동안 이동한 전체 거리는 발치 후 4주에 비해 1주에 견인한 경우에서 크게 나타나는 경향을 보였다. 4.발치 후 4주에 견인한 경우에 비하여 1주에 견인한 경우에서 유해한 조직소견이 나타나지 않았다. 이상의 결과는 발치 후 교정력 부여 시 조기 적용이 유리함을 시사하였다. This study was performed to compare and analyze the mode of tooth movement according to the timing of orthodontic force application after extraction. The upper right and left third incisors were carefully extracted at three-week interval in four adult dogs. Both canines were used as an anchorage for the bodily movement of the upper second incisors. Orthodontic force of 100 gm was simultaneously applied at one week after extraction on one side and four weeks after extraction on the other side using NiTi closed coil spring. While orthodontic force was applied for twelve weeks, the amount of tooth movement was measured at every second week with digital calipers. The animals were sacrificed at twelve weeks and histologic examination was executed to reveal any difference between both sides. The results were obtained as follows : 1.The tooth movement was likely to be faster in four-week side than one-week side for the first two weeks while faster in one-week side during next two weeks 2.The rate of tooth movement was fastest during four to six weeks period, then decreased gradually. 3.The total amount of tooth movement was likely to be larger in one-week side compared to four-week side. 4.Any damage to tooth and periodontal tissue could not be seen in the histologic section of one-week side. These results suggest that earlier application of orthodontic force is better than later after extraction in terms of the rate of tooth movement.

電氣工學敎育科 敎育課程 改善에 關한 硏究

韓相玉,金良模,琴得鉉 충남대학교 공업교육연구소 1981 論文集 Vol.4 No.1

In this paper, authors intended to develope a new curriculum for the Electrical Engineering Department, College of Industrial Education. First of all, the goal of the department was reviewed and major subjects were reorganized into four courses, intensifying the basic scholastic ability. And a systematic approach for effective institutional practice and industrial experience was studied.

발치 후 교정력 적용 시기에 따른 치아 이동 양상

한성호,황현식 전남대학교 치과대학 1999 전남치대논문집 Vol.11 No.1

This study was performed to compare and analyze the mode of tooth movement according to the timing of orthodontic force application after extraction. The upper right and left third incisors were carefully extracted at three-week interval in four adult dogs. Both canines were used as an anchorage for the bodily movement of the upper second incisors. Orthodontic force of 100 gm was simultaneously applied at one week after extraction on one side and four weeks after extraction on the other side using NiTi closed coil spring. While orthodontic force was applied for twelve weeks, the amount of tooth movement was measured at every second week with digital calipers. The animals were sacrificed at twelve weeks and histologic examination was executed to reveal any difference between both sides. The results were obtained as follows; 1. The tooth movement was faster in four-week side than one week side for the first two weeks while faster in one-week side during next two weeks 2. The rate of tooth mevement was fastest during four to six weeks period, then decreased gradually. 3. The total amount of tooth movement tended to be larger in one-week side compared to four-week side. 4. Any damage to tooth and periodontal tissue could not be seen in the histologic section of one-week side. These results suggest that earlier application of orthodontic force is better than later after extraction in terms of the rate of tooth movement.

간세포암의 십이지장침윤에 의한 상부위장관 출혈 1 예

유태현,한광협,박성하,김형길,문영명,한재호,조상호 대한소화기내시경학회 1999 Clinical Endoscopy Vol.19 No.2

Recent advances in both the diagnosis and treatment of hepatocellular carcinoma have improved the prognosis and changed the clinical significance of the recently increasing distant metastases. Distant metastases found after successful treament of the primary lesions are of great clinical significance for the treatment of hepatocellular carcinoma. The duodenum is a rare site of hematogenous metastases or direct invasion from hepatocellular carcinoma. A 23 year old man was admitted with upper gastrointestinal bleeding. He had been diagnosed with hepatocellular carcinoma and treated by a left lobectomy and chemoembolization. The patient was admittted for 12 months after the treatment of the primary tumor. Endoscopic examination revealed a mass in the duodenal bulb that protruded into the lumen. He died due to massive hematemesis. We report on a rare case of hepatocellular carcinoma with duodenal invasion in a 23-year-old male patient.

UPFC를 이용한 전력계통의 융통전력 증대방안에 관한 연구

김재현,김양일,정성원,한양주 국립7개대학공동논문집간행위원회 2004 공업기술연구 Vol.4 No.-

Recently electrical industry has been rapidly restructured by deregulation in the developed countries. This paper focuses on the evaluation of UPFC control on available transfer capability(ATC) enhancement. Technical merit of UPFC technology on ATC boosting are analyzed. More effective control means for line flow and bus voltage are required for appling UPFC. The function of UPFC is to control the active and reactive powers and the voltage magnitude simultameously. This paper demonstrate enhancement of ATC by application of UPFC at IEEE 57-bus system.

S.D. Rats를 이용 1, 1-Dichloro-1-fluoroethane의 아민성 흡입독성 연구

김현영,이성배,임철홍,김철우,점용현,한정희,전윤석,최수영,강대봉,이용묵 한국환경독성학회 2002 환경독성보건학회지 Vol.17 No.1

There were no specific effects for test materials on Sprague-Dawley (S.D.) rats in clinical symptoms, amounts of food intakes, weight changes, laboratory findings, and pathology after whole body l, l-Dichloro-1 -fluoroethane (used as coolant, metal cleaner and solvents) exposure(0, 1,500, 3,000, and 6,000 ppm) for 13 weeks (6 hour/day, 5 days/week). However, the loss of capillary vessels in eyeball (pupil) was observed in a female rat among 6,000 ppm group. Though there was a tendency for MCHC (Mean Corpuscular Hemoglobin Concentration) in rat to be decreased (p<0.05), it was not regarded as abnormal because the values were within normal limits. In asthma-stimulation related evaluations, there was also a tendency for inflammatory cell counts in bronchoalveolar lavages to be increased. But it had no statistical significance, and also no dependency on sex and the exposed concentration. Based on this result, the non observed effect level (NOEL) induced by 1, 1-Dichloro-l -fluoroethene inhalation was evaluated in groups with 3,000 ppm below (S .D. Rats, 13 weeks). Finally, it was concluded that the short term exposal of 1, 1-Dichloro-l-fluoroethane is not considered as a asthma stimulant by inhalation despite of some study limitations such as test animals use and short-term exposure .

상행성 운동마비와 보행 실조로 발현한 비전신성 혈관염성 신경병증 1예

김현석,김성민,권기한,이병철,신준현,강인수 대한노인병학회 1999 Annals of geriatric medicine and research Vol.3 No.4

알렉시딘과 차아염소산나트륨의 화학적 상호반응 후 mass spectrometry를 이용한 파라클로로아닐린의검출 분석

김현식,한승현,오소람,임상민,구유,금기연 大韓齒科保存學會 2010 Restorative Dentistry & Endodontics Vol.35 No.4

근관세척제인 NaOCl과 CHX를 병행 사용하는 경우 적갈색의 발암물질로 알려진 PCA가 생성된다. 본 연구의 목적은 CHX와 유사한 buigunide 계통의 소독제 인 ALX을 NaOCl 과 흔합 반응 시 PCA가 생성되 는지 여부를 mass spectrometry를 이용하여 평가하고자 하였다. 대조군으로는 4% NaOCl 용액과 2% CHX의 혼합용액, 0.5%PCA 용액, 및 1%ALX 용액을 사용하였고 실험군으로는 5가지 농도(1%, 0.5%, 0.25%, 0.125%, 0.0625%)의 ALX 용액과 4% NaOCl의 흔합용액을 질량분석기를 이용하여 mole-cular peak를 분석한 결과 ALX과 NaOCl의 혼합물에서는 PCA(m/w=128)로 보이는 128 피크가 관찰되지 않았다. 또한 용액의 색 변화에서도 ALX이 농도가 높을수록 열은 노랑색을 띄었으나 농도가 낮아질수록 흰색으로 관찰되었으며 어떠한 침전물의 형성도 보이지 않았다. Recent studies demonstrated that the combination of chlorhexidine (CHX) and sodium hypochlorite (NaOCl) resulted in the formation of a precipitate, para-chloroaniline (PCA). Alexdidine (ALX) is a kind of biguanides like CHX, and has stronger detoxification effect against the bacterial virulence factors such as lipoteichoic acid and lipopolysacchardide compared with CHX. The purpose of this study was to determine whether PCA was formed after chemical interaction between ALX and NaOCl using mass spectrometry. Mass spectrometry was performed for the mixture of five different concentrations of ALX (1, 0.5, 0.25, 0.125, 0.0625%) and 4% NaOCl. Results showed that the peak of PCA was not detected in mixed solu tions of ALX and NaOCl in mass spectrometry analysis. The color of mixed solution of ALX and NaOCl after chemical interaction was light yellow to white, but there wasn't any precipitate found.

크롬(Ⅵ)의 체내 흡수와 소실속도에 관한 연구

김현영,이성배,임철홍,이권섭,정용현,이종성,한정희,전윤석,황호순,이용묵 한국산업위생학회 2003 한국산업보건학회지 Vol.13 No.1

The CrO3 mostly used in plating. metal surface disposal, leather, cosmetic manufacturing, as an experiment material by repeatedly inhaling and exposure the male S.D. rats at a 0.00, 0.2., 0.50, 1.25 mg/㎡ concentration(particle size: 0.5-0.5 aerosol)6hours a day, 5day a week in 13weeks comparing with 2weeks, 8weeks of recovery group about the noxiousness of the experiment animal and the reduce scale of the CrO3 in the internal organ especially in blook and respiratory organ with the period of convalescent and clearance. The experiment results which we received are as follows. 1. In blood the RBC, HGB and HCT experiment, rats with 0.20, 0.50 mg/㎡ concentration showed that there were some decreases but not dependent. The kidneys absolute weight compared with control group was reduced intentionally(p〈0.05) and the lungs absolute weight compared with control group showed intentional increase(p〉0.05). 2. After the exposure of the experiment material, the whole blook, l\blood plasma and red blood cell in blood by (x): the period of convalescent, per (y); the decreasing of Cr concentration, was y=66.51 e -0.057x, y=67.2 e-0.101x, y=70.01 e-0.030 in 0.50 mg/㎡ exposure concentration by calculating the clearance coefficient of correlation, and the half life (day)was estimated 12.0, 6086, 23.0 each. 3, After the exposure of the experiment material, the experiment animals lung, liver and kidneys by(x); the period of convalescent, per (y); the decreasing of Cr conentration, was y=1808 e-0.00493x, y=12.02e-0.0297x, y=67.61 e-0.0292x in 0.50mg/㎡ exposure concentration by calculating the clearance coefficient of correlation, and the half life(day)was estimated 140.6, 23.3, 23.7, each, and including lung, liver with all of the experiment internal organs, the Cr clearance decreased as the exposure concentration increased.