완충재에 의한 바닥충격음 차음성능 분석에 관한 실험적 연구

윤세철,오종민 경희대학교 2003 環境硏究 論文集 Vol.12 No.-

Floor-impact sound in urban apartment has bean regarded as one of major sources which induces residential complaints. It is mainly due to design light-weight structure. The vibration arisen from the impact on one part of the apartment would be transfered to the other parts of the building without complete alleviation. As a result, the impact sound from upstairs annoys the residents downstairs. This study was carried out in order to assess the insulation performance of floor-impact sound for twelve isolators.

부하순환 하에서 제V급 복합레진 수복물의 미세변연누출에 대한 재접착제의 효과에 관한 연구

윤연희,김영재,김정욱,장기택,이상훈,김종철,한세현 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.3

저점도의 레진을 복합레진 수복물 위에 도포하는 것은 미세누출방지와 변연 완전성(integrity) 유지를 위한 한 방법이다. 하지만 장기간 관찰하면, 수복물은 저작압에 의한 영향을 받게 되는데, 저점도의 레진으로 수복물 변연부를 재접착(rebonding)하였을 때 저작압에 의한 응력에 견디면서 계속하여 수복물에 긍정적인 영향을 주는지에 대한 연구는 미흡한 실정이다. 본 연구는 부하순환(load cycling) 하에서 제Ⅴ급 수복물의 미세변연누출에 대한 재접착제 (rebonding agent)의 효과를 알아보고자 하였다. 40개의 건전한 소구치의 협면에 제Ⅴ급 와동을 형성하고 제조사의 지시대로 광중합복합레진으로 수복하였다. 20개씩 무작위로 나누어 표면전색을 하지 않는 Ⅰ군과 표면을 산부식 후 재접착한 Ⅱ군으로 설정하였다. 열순환 후 각 군에서 10개씩의 하위군 (A군=No load cycling군, B군=Load cycling군)으로 나누어 이중 B군의 시편에 1 Hz의 속도로 수직력이 4-100까지 100,000회의 부하순환을 가하였다. methylene blue용액에 침윤시켜 변연의 미세누출릉도를 평가하여 다음과 같은 결과를 얻었다. 1. 교합변연에서는 재접착과 무관하게 유의한 차이가 없었다(ⅠA-ⅡA군, ⅠB-ⅡB군) (p>0.05). 2. 치은변연의 경우는 부하순환을 하지 않은 군의 경우 재접착을 한 군(ⅡA군)이 재접착을 하지 않은 군 (ⅠA군)에 비해 더 적은 미세누출결과를 보였다(p<0.05). 3. 치은 변연에서 부하순환을 시행한 군의 경우에는 재접착을 한 군(ⅡB군)과 재접착을 하지 않은 군 (ⅠB군)과 유의차가 없는 비슷한 미세누출의 결과를 보였다(p>0.05). One clinical technique recommended f3r improving marginal integrity is "rebonding" or application of unfilled resins to the surface of composite restoration. But continuously the restorations are affected with occlusal load. There is room for doubt that the rebonding agent has the positive effect on microleakage in spite of the stress generated by the occlusal load. This study determined the effect of rebonding on microleakage of Class Ⅴ resin composite restorations under load cycling. Class Ⅴ cavities were prepared on the buccal surface of 40 sound extracted premolars and restored with a hybrid light-cured resin composite according to manufacturers' directions. They wert randomly divided into two groups consisting of 20 samples a control(group Ⅰ), without surface sealing, and the other group (group Ⅱ) in which margins were etched and rebonded. After thermocycling, each of groups was divided into subgroups (group A, B), and load cycling(total 100,000 cycles with 4-100N load at a rate of 1 Hz) were applied on the group B. Assessment of microleakage utilized methylene blue dye penetration. The following results were obtained : 1. In the occlusal region, no significant difference was noted in the scores regardless of whether or not the rebonding agent was used (group ⅠA-ⅡA, ⅠB-ⅡB) (p>0.05). 2. In the cervical region, the control group with rebonding (group ⅡA) showed the better result than the group without rebonding (group ⅠA) (p<0.05). 3. In the cervical region, the rebonded group with load cycling(group ⅡB) showed similar results to the groupf·ithout rebonding(group ⅠB) and no significant difference was noted(p>0.05).

상악 측절치의 치내치에 대한 증례보고 : REPORT OF 2 CASES

윤석희,이재천,김영재,장기택,한세현,김종철 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.3

치내치(dens invaginatus)는 치아 발생 과정 중 경조직이 석회화되기 전에 법랑질 상피가 함입되어 생기는 치아 기형이다. 치내치는 함입된 정도에 따라다양한 형태학적 변이를 보이는데 이러한 기형은 미생물이 침입할 수 있는 통로가 될 수 있어 치수조직의 괴사와 치근단 농양 또는 치은 농양의 원인이 된다. 이러한 경우 근고나의 복잡한 해부학적 형태 때문에 근관 치료가 매우 어렵다. 본 증례는 상악 좌측 측절치의 동통을 주소로 내원한 두 명의 환아들에 관한 것이다. 첫 번째 증례는 수산화 칼슘제재를 이용한 근관치료를 시행하여 양호한 결과를 얻었고 두 번째 증례는 치아를 발거하였다. 발거된 치아는 미세전산화 단층촬영을 이용하여 해부학적 형태를 살펴보았기에 보고하는 바이다. Dens invaginatus is a malformation of tooth resulting from an infolding of the enamel epithelium during tooth development. This malformation shows a broad spectrum of morphologic variations. This invagination frequently allows the entry of irritants and microorganism, which usually lead to necrosis of the adjacent pulp tissue and then to periapical or periodontal abscess. Root canal treatment of such tooth is often difficult because of the unusual form and complicated pulpal space. This article reports 2 cases of dens invaginatus in maxillary lateral incisors. The first case was successfully treated with Ca(OH)₂. In the second case, involved tooth was extracted and this extracted tooth was observed using the micro-computed tomography.

고강도강을 활용한 차량 경량화 동향 리뷰

김세호,윤재웅 대구대학교 산업기술연구소 2014 産業技術硏究 Vol.25 No.1

Weight reduction of the vehicle is strongly enforced globally due to the regulation of the fuel efficiency and emission. In this review, the R&D tends are briefly explained for the application of the high strength steel to vehicle structure for the weight reduction among many techniques. The weight portion of the body in white in the foreign exhibition shows that high strength steels are widely used with the newly developed stamping techniques. This review also illustrate stamping techniques such as hot press forming, roll forming, roll forming, servo-press and drawing process with 1Gpa-steel, which are widely appled to the manufacturing process of high strength auto-parts.

전자코를 이용한 대두유의 산패도 판별

윤예리,한기영,김정환,오세연,노봉수 서울여자대학교 자연과학연구소 2005 자연과학연구논문집 Vol.17 No.-

대두유를 160, 190, 220℃에서 가열하면서 3시간 또는 4시간 간격으로 시료를 취하여 6개의 metal oxide sensor로 구성된 전자코와 2세대 전자코인 GC-SAW를 바탕으로 한 전자코를 사용하여 분석하였다. 주성분 분석결과 가열처리시간과 온도가 증가할수록 제1 주성분 값이 감소하는 것을 볼 수 있었다. 즉, 초기의 열처리를 하지 않은 신선한 대두유와 가열처리된 대두유를 구분할 수 있었다. 특히 190℃와 220℃의 높은 온도에서는 3시간 내지 4시간이면 대두유의 산패가 많이 진행됨을 알 수 있었다. 또한 GC-SAW를 바탕으로 한 전자코를 이용한 결과도 가열온도와 시간이 증가할수록 peak의 수와 면적이 증가함으로써 열처리시간에 따른 패턴 변화를 확인할 수 있었다. 이것으로 대두유의 가열처리에 따른 산패취의 변화를 측정하기 위한 간단한 방법으로 사람의 코처럼 미묘하고 복잡한 향기와 냄새성분을 감지할 수 있는 전자코로 평가할 수 있음을 확인하였다. The discrimination of the heated soybean oil was investigated by using electronic nose. Volatile components from these products were discriminated by six metal oxide sensors. Principal component analysis showed the differences between non-heated soybean oil and heated soybean oil. The first principal component score in soybean oil was reduced from +0.369 score to -0.242 score as the heating time increased. As heating temperature increased, the ratio of resistance decreased, indicating that rancidity of soybean oil increased at high heating temperature. As an alternative, electronic nose based on GC with SAW(surface acoustic wave) sensor was used for discrimination of heated soybean oil. High resolution olfactory imaging, called VaporPrint^(TM), was shown to be particularly useful for evaluating oil quality in its entirety. The result of electronic nose showed significant changes in volatile profiles from soybean oil. Also, peak numbers and areas increased as high heating time and temperature. Analysis using electronic nose with pattern recognition was rapid and simple. And this technique could be an efficient method to predict shelf-life and evaluate quality in food.

Ferric sulfate를 이용한 유치치수절단술의 3년 후 임상평가

윤연희,장기택,한세현 大韓小兒齒科學會 2002 大韓小兒齒科學會誌 Vol.29 No.1

15.5% ferric sulfate solution을 이용하여 유치치수절단술을 시행한 유구치의 상태를 임상적, 방사선학적으로 평가를 하여 이를 20%로 희석한 formocresol로 치수절단술을 시행한 경우와 비교하였다. 1997년부터 1998년까지 서울대학교병원 소아치과에서 치료를 받은 건강한 환아를 대상으로 하였고, ferric sulfate를 이용한 치수절단술을 치료받은 30개의 치아와 20%로 희석한 formocresol로 치수절단술치료한 23개의 치아, 총 53개의 치아를 평균 34개월 후 follow-up하여 그 임상적, 방사선학적 상태를 조사하였다. ferric sulfate군의 전체적인 성공률은 80.0%이었고, formocresol군의 성공률은 81.0%이었다. 두 군의 결과 차이를 카이제곱검정의 통계방법으로 분석하였다. ferric sulfate군의 4개의 formocresol군의 4개의 차이가 외흡수를 보였고 근단부 치조골파괴는 ferric sulfate군의 3개와 formocresol군의 2개에서 보였다. ferric sulfate군과 formocresol군 사이의 성공률은 통계학적으로 유의한 차이를 보이지 않았다. The objective of this report is to assess clinically and radiographically the state of the primary molars pulpotomized with a 15.5% ferric sulfate solution. The subjects selected were healthy children treated at the pediatric dental clinic of the Seoul National University Hospital in Korea. Thirty teeth were pulpotomized with a ferric sulfate solution(FS). Another twenty-one teeth were pulpotomized with 20% dilute formocresol(FC). Clinical and radiographic data for the fifty-one primary molars were collected with a mean follow-up period of 34 months. The success rate for the FS group was 80.0%. The success rate for the FC group was 81.0%. The differences in the results between the two groups were analyzed statistically utilizing the chi square test. External root resorption was observed in four teeth of FS group and four of the FC group. Periapical bone destruction was observed in three of FS group and two of FC group. There were no significant statistical differences between the success rates for FS group and the FC group.

C++클래스 프로그래밍 지원 도구

오세만,연주흠 東國大學校 1992 東國論叢 Vol.31 No.-

The C++ language is object-oriented programming language which is derived from C language. Although C++ language is based on conventional programming language, it has few drawbacks in use. Particularly, the class programming which enables the reuse of the program is very hard without a supporting tool. When we program the software package using C++ ckasses, we need an information about the relating classes. To accomplish this, we have implemented a system which aids the C++ class programming. The main works of this system are that information about classes in acquired automatically and programmed classes can be added to the class library with very little effort. The system extracts information form classes by parsing the C++ source code and manages class library based on class inheritance hierarchy. And then this information about classes and the class source code are provided when the class library is browsed. So we can do the C++ class programming easily by using the system.

한ㆍ미간 마케팅 정보시스템 현황에 관한 연구

이세래,진광윤 三陟大學校 2001 論文集 Vol.34 No.1

Nowadays Korea has many difficulties in computer industry because of the rapid environmental changes in Korean computer market according to the free import. To cope with those dangers and to make an effective marketing strategy, we should make use of non-skillful marketing information including price, design, after service, company's image and so on. Although the accelerated development of computer-related techniques has improved the supply of information, many marketing managers are not completely with their own information system. The purpose of this study is to analysis the contents and application degree of Marketing Information System between Korean and U.S. The concrete items I would like to study in this paper are as follows : 1.Literature review of Marketing Information System 2.Application degree of Marketing Information System in U.S. 3.Comparative analysis of Marketing Information System between Korean and U.S.

뇌경색후 발생한 Cortical Spreading Depression과 뇌경색 범위에 관한 실험적 연구

박윤관,이승민,김세훈,이기찬,주정화,이훈갑 대한신경외과학회 1996 Journal of Korean neurosurgical society Vol.25 No.3

Cortical Spreading Depression(CSD) is a transient depression of neuronal activity that spreads across the cortical surface and is associated with profound changes in blood flow, extracellular ion concentration. Direct Current(DC) potentials and cell membrane potentials. One of the electrophysiological disturbance in the periinfarct surrounding is spontaneous occurrence of repeated CSD like DC shifts associated with increased energy demand. Due to restricted blood flow to the periinfarct border zone, elevated metabolic demand is potentially harzardous. So the authors designed this experiment to verify the correlation between periinfarct cortical spreading depression and ischemic volume following permanent middle cerebral artery (MCA) occlusion in rats. Sprague-Dawley rats(n=27) were anesthetized with 0.5∼1% halothane, and artificially ventilated through a tracheal cannula. Arterial pressure, blood gases and body temperature were controlled. The middle cerebral artery(MCA) was occluded distally to the lenticulostriate branches. Measurements of CSD activity were made for 4 hours in each animal. Infarct volume was determined 6 hours later in 2, 3, 5-triphenyl tetrazolium chloride(TTC)-stained sections. For 4 hours after MCA occlusion, the CSDs were found in all experimental animals with a range of 2∼9 times. Those CSDs wer of varying duration, : "small"(<1 min) and "big"(> 1 min) SDs and mean of total duration of SD was 10.5±10.3 min during 4 hours of MCA occlusion. Neuropathological evaluation of brain infarct in the rats, which had been allowed to survive for 6 hours after MCA occlusion showed a mean volume of 89.7±45.3㎣. Serial observation of duration of CSD showed progressive prolongation only in 8 rats. The rest of them(n=19) did not show any prolongation. Neither the prolongation of duration of CSD nor the frequency of CSD in the penumbral zone correlated with the volume of infarct. However total duration of CSD was slightly related with the infarct volume after 6 hours of the permanent MCA occlusion(r=0.414, p=0.0318).

줄넘기 運動의 有ㆍ無酸素的 運動强度 역치수준 設定을 위한 硏究

盧成圭,윤재원,김두경,하명수,장세원,윤중현 江原大學校附設體育科學硏究所 1987 江原大學校附設體育科學硏究所論文集 Vol.- No.12

The purpose of this study was the level of Aerobic-Anaerobic exercise intensity according to Rope skipping frequency by the skipping type at different age group(Middle, Junior high school and collegean). Types of Rope skipping(Jump, Leap and Double jump) with 100 rounds per min(5min), 120 rounds per min (5min) and max round frequency were tested by 120 volunteer untrained men and women students (forty middle school, forty high school and forty collegean) form Oct. 10. 1987 to No V.5. 1987. The results are showed at the skip intensity of 120 rounds per min. was higher than that of 100 rounds per min. at all skipping types, and men students showed less HR than women students. From the testing result, Double Jump was Considered as Anaerobic Exercise, Tean Jump was determined the strongest Aerobic exercise, and Jump or Leap were moderate Aerobic exercise. Recommending round frequency per min from multiple regression were follows. ----------------------------------------------------------------------------- Type Age 15 18 21 duration Sex ----------------------------------------------------------------------------- Jump man 127☆ 147 167 5min woman 113 126 140 5min ----------------------------------------------------------------------------- D.Jump man 137 169 211 2min woman 126 155 183 2min _____________________________________________________________________________ ☆ Round numbers per min