Flowable 및 microfill 복합레진으로 충전된 제 5급와동에서 load cycling 전,후의 미세변연누출 비교

강석호,김오영,오명환,조병훈,엄정문,권혁춘,손호현 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.2

Low-viscosity composite resins may produce better sealed margins than stiffer compositions (KempScholte and Davidson, 1988; Crim, 1989). Flowable composites have been recommended for use in Class V cavities but it is also controversial because of its high rates of shrinkage. On the other hand, in the study comparing elastic moduli and leakage, the microfil had the least leakage (Rundle et al. 1997). Furthermore, in the 1996 survey of the Reality Editorial Team, microfills were the clear choice for abfraction lesions. The purpose of this study was to evaluate the microleakage of 6 composite resins (2 hybrids, 2 microfills, and 2 flowable composites) with and without load cycling. Notch-shaped Class V cavities were prepared on buccal surface of 180 extracted human upper premolars on cementum margin. The teeth were randomly divided into non-load cycling group (group 1) and load cycling group(group 2) of 90 teeth each. The experimental teeth of each group were randomly divided into 6 subgroups of 15 samples. All preparations were etched, and Single bond was applied. Preparations were restored with the following materials (n=15) : hybrid composite resin [Z250(3M Dental Products Inc. St.Paul, USA), Denfil(Vericom, Ahnyang, Korea)], microfil [Heliomolar RO(Vivadent, Schaan, Liechtenstein), Micronew(Bisco Inc. Schaumburg, IL, USA)], and flowable composite[AeliteFlo(Bisco Inc. Schaumburg, IL, USA), Revolution(Kerr Corp. Orange, CA, USA)]. Teeth of group 2 were subjected to occlusal load (100N for 50,000 cycles) using chewing simulator(MTS 858 Mini Bionix Ⅱ system, MTS Systems Corp., Minn, USA). All samples were coated with nail polish 1mm short of the restoration, placed in 2% methylene blue for 24 hours, and sectioned with a diamond wheel. Enamel and dentin/cementum margins were analyzed for microleakage on a sclale of 0 (no leakage) to 3 (3/3 of wall). Results were statistically analyzed by Kruskal-Wallis One way analysis, Mann-Whitney U-test, and Student-Newmann-Keuls method. (p=0.05) Results: 1. There was significantly less microleage in enamel margins than dentinal margins of all groups. (p<0.05) 2. There was no significant difference between six composite resin in enamel margin of group 1. 3. In dentin margin of group 1, flowable composite had more microleakage than others but not of significant differences. 4. There was no significant difference between six composite resin in enamel margin of group 2. 5. In dentin margin of group 2, the microleakage were R>A=H=M>D>Z. But there was no significant differences. 6. In enamel margins, load cycling did not affect the marginal microleakage in significant degree. 7. In dentin margins, load cycling did affect the marginal microleakage only in Revolution. (p<0.05)

一部 美容業 從事者들의 織責別 腰痛 有病率과 關聯要因

김춘일,박종,류소연,김석산,김기순,하상호,변주남 조선대학교 부설 의학연구소 1999 The Medical Journal of Chosun University Vol.24 No.1

To find the prevalence and related factors of low back pain experienced by some beauticians. a survey was made toward 252 beauticians in Kwangju City from March 1st to April 1st, 1998. The results were as follows; 1. The prevalence rate of low back pain among the respondents for the last week was 59.5%. 2. The aid group and staff group with low back Pain had significantly longer duration of work than those without low back pain. Managers who had bad posture with twisted or too much extended back showed a significantly higher prevalence of low back pain than those with good posture during work(P<05). 3. Aid group with low back pain showed significantly higher points at total stress score, depression score, general health score and vitality score than those without low back Pain. The staff group with low back pain showed significantly higher points for total stress score, sleep disorder and anxiety score, depression score, general well-being and vitality score than those without low back pain. Managers with low back Pain showed significantly higher points of stress at social performance and self confidence (P<05) than those without low back pain. The above results suggest that low back pain is related to different jobs and work environments for beauticians. So effective measures and further studies against risk factors must be made considering their jobs. To prevent or reduce low back pain, appropriate management of stress for beauticians is necessary.

고온에서 폴리에틸렌의 크리프특성에 관한 연구

姜錫春 水原大學校 2007 論文集 Vol.25 No.-

When a material is soft as plastics, creep is one of major criterions for failure mechanism of machine elements. One of the popular thermo-elastic plastics, polyethylene which is used for a engineering purpose as it has good mechanical properties compare to other plastics was used to test of creep effect at room and elevated temperatures. From the research the creep curve of plastic(polyethylene) is different from metals which have 3 stage before creep failure at various stresses and temperatures. For various test conditions they have only third stage which is called as a acceleration step, and than failed. As the stress(load) was increased, the strain rate was increased more rapidly. When the temperature is higher than room temperature, the creep of plastics were more sensitive criterions for the design of machine elements, and applied stress should be reduced for the application at elevated temperatures for their proper functions as machine elements.

언밸런싱량을 이용한 주축의 에러보정

임정숙,정원지,이춘만 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

Spindle design is very important to improve the competitive power in production cost of high quality machine tools. In this paper, spindle system was designed with built-in motor can be used to simplify the structure, to improve the machining frexibility, and to perform high speed machining of machine tools. According to the spindle speed is high, spindle end's displacement is considered to be an important subject. To know how the unbalanced mass affect to the spindle end displacement, modal analysis was performed and analyzed. When, unbalanced mass was 0g, spindle front end displacement was a minimum, and unbalanced mass was 20g, spindle rear end displacement was kept to a minimum.

말기심부전 환자의 부전심장에서의 장바이러스와 인형 거대세포바이러스 감염양상

최성준,김석연,홍석근,김효수,오병희 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.9

사염화탄소로 유발된 간손상에서의 효소 활성도의 변화로 본 홍화자 분획물의 간손상 보호 작용

정춘식,정기화,정정숙 德成女子大學校 藥學硏究所 1999 藥學論文誌 Vol.10 No.1

본 연구소에서는 사염화탄소로 유발된 간손상에 대한 홍화자 메탄올 추출물과 이를 계통 분획한 분획물의 보호 효과를 이미 보고하였다. 본 실험에서는 혈장과 조직 생화학적 분석으로 홍화자 분획물의 간보호 효과를 확인하며, 간보호 작용에 대한 기전을 살펴보기 위하여 약물 대사 효소에 미치는 영향을 측정하였다. 홍화자 butanol subfractions 중 BS-5 분획물은 CCl_4로 간손상을 유발시킨 흰쥐에서의 혈장 ALT와 AST 활성과 간조직 중 cholesterol and triglyceride를 감소시켰으며, 이러한 BS-5 분획물의 CCl_4로 유발된 간손상에 대해 보호 작용은 cytochrome P450 감소와 glutathione S-transferase의 활성 증가에 기인된 것으로 생각된다. Previous studies have shown that methanol extract and its butanol fraction of Carthamus tinctorius L. Semen have the hepatoprotective effect on the CCl_4-induced hepatotoxicity. The hepatoprotective effect of subfractions has been evaluated by analyzing blood and hepatocyte biochemical analyses and biotransformation enzyme analyses. Treatment of BS-5 subfraction has significantly decreased the activities of alanine aminotransferase and aspartate aminotransferase. In addition, the levels of cholesterol and triglyceride in liver have been decreased as compared with that of CCl_4 treated rats. The hepatoprotective effect of BS-5 subfraction on the CCl_4-induced hepatotoxicity would be mediated of the attenuation of the level of cytochrome P450 and the enhancement of the activity of glutathion S-transferase.

經營學硏究와 周邊社會科學의 貢獻

趙錫俊 건국대학교 행정대학원 1968 行政學報 Vol.1 No.1

市場國際化를 위한 國內企業의 法的 課題로서의 製造物責任에 관한 硏究

徐圭錫,金玟中,洪春義 全北大學校 1993 論文集 Vol.35 No.-

Produkthaftung ist die durch Produkt, also durch Wirtschaftgu‥ter ausgelo‥ste Haftung. Eine Definition der Produkthaftung im Sinne des Produkthaftungsrechts enthaβlt die Verpflichtung, fu‥r Scha‥den zu haften, dieaus der Benutrung, aus den Ge-oder Verbrauch von fehlerhaHen Produkten entstehen. Da der Herstellereines Produkts nicht nur seinen unmittelbaren Vertragspartnern SorfEltspflicht schuldet, geho‥rt es zum haftungs-rechtlichen Kernbereich der Produkthatung einen Schadensersatz auch gegenu‥ber Dritten zu gewa‥hrleisten.Fu‥r die Untersuchung zur Produkthaftung als rechtliche Aufgabe der internationalen Industrie haben dieVerfasser vier mo‥gliche Themenbereiche ausgewa‥hlt. In einem ersten Kapital werden haftungsrechtliche Grund-sftze im modernen Produkthaftungsgesetz(und Produkthaftungsgesetz - Entwurf) und deren Tendenz der Ent-wicklung unter Beru‥cksichtigung der letzten internationalen Geseftgebung dargestellt. Das zweite Kapital derUntersuchung ist der Produkthaftung in den USA gewidmet. Die Produkthaftung in der EG wird im drittenKapital behandeit. Das vierte Kapitel wird sich mit der Produkthaftung in Japan beschliftigen.Aus der Untersuchung lassen sich im wesentlichen folgende herausstellen 1. Als wesentliche Tendenz unterstellt das moderne Produkthaftungsgesetz(und produkthaftungsgesetz -Ent- wurf) der yerschuldensunaba‥ngigen Gefa‥hrdungshaftung. Mit der Gefa‥hrdungsprodukthaftung sind fu‥rinternationale Industrie ku‥nftig erhebliche Belastungen verbunden. 2. Eine weitere Tendenz gegenu‥ber dem bisherigen Recht besteht darin, daβ jede Person, die sich alsHersteller ausgibt, sowie der Importeur, der aus Ausla‥nder einfu‥hrt, und auch der Lieferant der Haftungunterworfen werden. 3. Der Hersteller muβ fu‥r Entwicklungsrisiken nicht haften, wenn der Hersteller daru‥ber beweisen kann,daβ es sich im konkreten Fall um ein Entwicklungsrisiko handelt. 4. Von der Haftung ausgenommen werden landwirtschaftliche Naturprodukte, z. B. Erzeugnisse des Bodens,der Tierrucht, der Imkerei und Fischerei sowie Jagdfeugnisse, die nicht einer ersten Verarbeitung unto

지하수위 고려방법에 따른 사면안전율의 비교연구

박춘식,장정욱,장일석 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-

This study examined soil parameters, existence of ground water, and the safety factors of slope according to the ground water level. The following are the conclusions of the study. (1) The safety factor became less as the ground water level decreased. (2) The greater the cohesion became, the less the safety factors according to the ground water level did. (3) In the case with ground water, greater cohesion had less effect on the safety factor. However, in the case without ground water, changes in cohesion had considerable effects on the safety factor. (4) While the safety factor increased associated with increase in the angle of shear resistance as the ground water level, the safety factor according to cohesion was almost constant.

절삭속도가 절삭온도와 공구수명에 미치는 영향(Ⅰ)

배춘익,장영석 慶南專門大學 1998 論文集 Vol.26 No.1