간접부착술식시 치면과 레진 베이스의 간격 및 접착제에 따른 결합강도

서미영,박병주,경희문,황현식 전남대학교 치의학연구소 2001 구강과학 Vol.13 No.3

The purpose of this study was to evaluate the feasibility of the combined use of paste resin with sealant as an adhesive of the indirect bonding. The resin bases made of lighcured resin were bonded to the bovine incisors at a distance of 0.0, 0.2 or 0.4mm using the sealant only or the mixture of sealant and paste resin. Bond strength of each group was measured using universal testing machine. The results were as follows: 1. The bond strength was reduced in both groups as the distance between enamel surface and resin base increased. 2. The bond strength showed no statistical difference between two groups in case the distance between enamel surface and resin base was 0.0mm. 3. In case the distance between enamel surface and resin base was 0.2 or 0.4mm, the sealant with paste resin group showed significantly higher bond strength than the sealant only group. The results of the present study indicate that the use of paste resin with sealant may be desirable as an adhesive in indirect bonding, particularly in case a gap is suspected between enamel surface and resin base.

탄소섬유 적층혼성부재의 계면수 변화에 따른 축 압궤 특성

서현경,박준우,양용준,황우채,양인영 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.1

알루미늄과 CFRP는 대표적인 경량화 재료이다. 알루미늄 부재는 안정적인 소성 변형에 의해 에너지를 흡수하며, CFRP 부재는 비강성과 비강도가 우수하고 불안정한 취성파괴로 인해 에너지를 흡수한다. 이러한 각각 알루미늄과 CFRP 부재의 압궤 특성을 기초로 두 재 료의 결합에 의해 서로의 장점에 대한 시너지 효과를 얻기 위해 혼성구조부재를 제작하였다. 본 연구에서는 알루미늄 부재의 외측을 CFRP로 강화시킨 혼성구조부채를 제작하여 CFRP의 계면수 변화에 따른 축 방향 준정적 압궤실험을 행하여 사각 및 원형 단변 모형의 혼성구조부재의 압궤 특성을 조사하였다. 실험 결과 혼성구조부재는 내부의 알루미늄 부재의 연성 성질 때문에 CFRP 부재의 불안정한 취성 파괴를 보완하여 비교적 안정적인 압궤 모드를 보였다. 하지만 혼성구조부재는 계면수 변화에 대해 에너지 흡수성과 압궤 모드는 별다른 영향을 보이지 않았다. The aluminum or CFRP is representative of light-weight materials. The aluminum tubes absorb energy by stable plastic deformation and the CFRP tubes absorbs energy by unstable brittle failure with higher specific strength and stiffness. Based on the respective collapse characteristics of aluminum and CFRP tubes, the aluminum CFRP compound tubes were manufactured to get a synergy effect when the aluminum CFRP tubes were combined with the advantages of each tube. This paper is to investigate the collapse characteristics of square or circular shaped aluminum CFRP compound tubes subjected to quasi-static axial collapse tests which were conducted by changing the stacking conditions. Test results showed that the collapse of the aluminum CFRP compound tubes complemented unstable brittle failure of the CFRP tube due to the ductile characteristics of the inner aluminum tube. It turned out that interlaminar numbers of aluminum CFRP compound tubes have no influence on the energy absorption and collapse modes of the tubes.

간접부착술식시 치면과 레진 베이스의 간격 및 접착제에 따른 결합강도

서미영,황현식 대한치과교정학회 2001 대한치과교정학회지 Vol.31 No.4

본 연구는 브라켓 간접부착술식시 치면과 레진 베이스의 간격 및 접착제에 따른 전단결합강도를 비교함으로써 브라켓 간접부착의 접착제로서 호제(paste)형 레진 병용의 타당성 여부를 평가해보고자 시행되었다. 소의 하악 중절치 120개를 실험재료로 하여 대조군의 경우 접착제로 실런트만을 사용하는 반면 실험군의 경우 실런트와 호제형 레진을 병용하여, 치면과 레진 베이스 간의 간격이 0.0, 0.2, 또는 0.4 mm가 되도록 접착한 다음 만능물성 시험기를 이용하여 각 시편의 전단결합강도를 측정하고 비교하여 다음의 결과를 얻었다. 1.치면과 레진 베이스 간의 간격이 멀어질수록 두 군 모두에서 전단결합강도가 감소하는 것으로 나타났다. 2.치면과 레진 베이스 간의 간격이 0.0 mm인 경우 양 군 간의 전단결합강도의 차이는 나타나지 않았다. 3.치면과 레진 베이스 간의 간격이 0.2, 0.4 mm인 경우 실런트와 함께 호제형 레진을 병용한 경우의 전단결합강도가 실런트만 사용한 경우에 비하여 통계적으로 유의하게 높게 나타났다. 이상의 연구결과는 브라켓 간접부착술식시 치면과 레진 베이스 간의 간격이 의심될 경우 브라켓 간접부착의 접착제로서 실런트만 단독 사용하는 것보다 호제형 레진을 병용하는 것이 유리함을 시사하였다. (주요 단어 : 간접부착술식, 전단결합강도, 레진베이스, 접착제) The purpose of this study was to evaluate the feasibility of the combined use of paste resin with sealant as an adhesive of the indirect bonding. The resin bases made of light-cured resin were bonded to the bovine incisors at a distance of 0.0, 0.2 or 0.4 mm using the sealant only or the mixture of sealant and paste resin. Bond strength of each group was measured using universal testing machine. The results were as follows : 1.The bond strength was reduced in both groups as the distance between enamel surface and resin base increased. 2.The bond strength showed no statistical difference between two groups in case the distance between enamel surface and resin base was 0.0 mm. 3.In case the distance between enamel surface and resin base was 0.2 or 0.4 mm, the sealant with paste resin group showed significantly higher bond strength than the sealant only group. The results of the present study indicate that the use of paste resin with sealant may be desirable as an adhesive in indirect bonding, particularly in case a gap is suspected between enamel surface and resin base. ※Key words : Indirect bonding, Bond strength, Adhesive, Resin base

Apriori 알고리즘을 이용한 적합한 정보 Profile 생성 기법

소현경,서영훈 충북대학교 컴퓨터정보통신 연구소 2004 컴퓨터정보통신연구 Vol.12 No.1

웹이 발달하면서 검색 데이터 양이 급격히 증가하고 검색 결과도 방대해 지므로 효율적인 검색이 불가능하게 되었다. 따라서 웹 기반 정보검색 시스템에서 사용자의 요구에 적합한 문서들을 제공하기 위하여 질의어 확장에 관한 연구가 활발히 이루어지고 있다. 기존의 시스템은 사용자가 요구하는 질의어에 관한 정보가 충분하지 못하였으므로 질의어의 출현 빈도수에 의존하여 적합한 문서의 우선순위를 결정하였으며 임계치가 검색 결과에 큰 영향을 미치고 있다. 또한 질의어와 유사한 용어를 사용한 문서일 경우 적합한 문서로 선택하지 못하는 용어 불일치 문제도 가지고 있다. 따라서, 본 논문에서는 용어 불일치 문제를 해결하고, 사용자가 원하는 질의어에 대해 다양한 정보를 포함하고 있는 문서를 선택하기 위하여 자동적인 질의어 확장 방법을 제안한다. 질의어 확장을 위하여 백과사전 정보와 Apriori 알고리즘을 이용하여 적합한 정보 프로파일을 생성하였다. It is impossible to efficiently search the web document because of the increased searching data and searched results. Therefore, to provide the relevant document in web-based information search system, there are many researches for query expansion. Because the query-related information was not enough, previous systems determined the priority of the relenvant document using the term-frequency of query, and used the threshold as the main factor for searching. And if the documents included the word similar to the query, these documents are not determined as relevant document in previous system. this problem is called the vocabulary mismatch problem. In this paper, we solve the vocabulary mismatch problem, and propose the query expansion method to select the documents which include the various information for query. To expand the query, we generate the relevant information profile using the encyclopedia information and Apriori algorithm.

구강검진에서 임상검사와 비교한 파노라마방사선사진의 유용성

안서영,안창현,최갑식 대한구강악안면방사선학회 2007 Imaging Science in Dentistry Vol.37 No.2

Purpose : To evaluate the efficacy of panoramic radiography by comparing the results of clinical examination with radiographic findings. Materials and Methods : We studied 190 patients (20 men and 170 women; mean age, 40 years; range, 22 to 68 years) who visited the health promotion center of Korea Medical Science Institute and were examined both clinically and by panoramic radiography. We compared results from both examinations. Treatment options by clinical examination were described as “no treatment indicated”, “treatment of dental caries”, “removal of calculus”, “treatment of periodontal disease”, “prothodontic treatment” and “extraction of the third molar”. Findings taken from the panoramic radiography were: dental caries, periapical lesion, alveolar bone loss, calculus deposition, retained root, impaction of the third molar, disease of maxillary sinus, bony change of mandibular condyle, etc. Results : The prevalence of panoramic findings were: 37.9% of dental caries, 17.4% of periapical lesions, 44.7% of alveolar bone losses, 62.6% of calculi deposition, 7.9% of retained roots, 26.8% of third molar impactions, 6.3% of diseases of maxillary sinus, 2.1% of bony changes of mandibular condlye and 35.8% of miscellaneous lesions. Abnormal conditions revealed by panoramic radiography which had not been discovered on clinical examination were: 24.2% of the patients had dental caries, 17.4% had periapical lesions, 7.4% had calculi deposition, 5.3% had retained roots, 15.3% had third molar impactions. The opposite cases were: 5.2% had dental caries, 12.6% had calculi deposition, and 9.5% had third molar impactions. Conclusion : The use of panoramic radiography as a supplement to the clinical examination might be a valuable screening technique.

춘ㆍ하계 도암만의 수질환경 특성

조현서 여수대학교 1998 論文集 Vol.12 No.2

This study was performed to characterize the water quality of Doam bay from March 8 to August 16,1997. Doam bay is located in the western part of south coast in Korea. The results are as follows: The northern part of surveyed area was highly effected from the freshwater of Tamjin river by the results of salinity and pH. Dissolved oxygen(DO) concentrations were slightly under saturated in the bottom layer at August, but more saturated at spring season. Ranges of suspended solid(SS) concentrations were 6.57~67.50mg/l, and showed the showed the highest mean values in bottom layer at June. Chemical oxygen demand(COD) concentrations showed the highest mean value of 1.98mg/l in surface layer of June. Dissolved incorganic nitrogen(DIN) concentrations showed the highest mean value of 2.97㎍-at/l in surface layer at May, while showed the lowest mean value of 0.92㎍-at/l in bottom layer of June. Dissolved inorganic phosphorus(DIP) concentrations was in the range of 0.06~3.18㎍-at/l. The highest mean value of 1.90㎍-at/l was in bottom layer of June. And, higher concentrations were showed in the northern inner area. Nitrogen is more limiting constituednt than phosphorous in the growth of phytoplankton in almost all area at all surveyed season by the results of lower N/P ratio than 16 of Redfield ratio. Eutrophication indices were slightly high in the northern inner area at May and June. But, they were lower in the other almost surveyed area.

자연의 아름다움과 고급스러움이 공존하는 마임 비에타 쇼룸 제안 -오감 (시각, 청각, 후각, 촉각, 미각)을 중심으로-

김보현,이서연,은다솜,엄연정,이진민,장미정,이성애 숙명여자대학교 산업디자인연구소 2017 숙명디자인학 연구 Vol.24 No.-

본 연구는 국내 브랜드 ‘마임'의 뷰티와 연계한 뷰티 쇼룸을 제안함에 있어서 공간속에 오감을 담아내는 일련의 프로세스를 밝히는데 목적이 있다. 이는 브랜드가 소유하고 있는 다양한 감각과 가치가 결여된 채 시각적 요소만이 담긴 브랜드 뷰티 쇼룸이 대다수를 차지하는 오늘날, 이에 대한 문제를 해결하기 위해 ’융합 연출 디자인'적 시점에서 폭넓게 바라보고 브랜드의 정신과 오감의 결합을 통해 이를 해결하고자 하였다. 이에 본 연구는 2017년 3월~6월 15주간 숙명여대 환경디자인학과 <융합연출 디자인>수업에서 진행된 수업의 결과물로서 산학 연계된 화장품 브랜드의 쇼룸디자인 개발 프로세스를 제안한다. 또한 본 연구의 범위는 오감을 담고 있는 뷰티 쇼룸(4D)이 되기까지의 과정 전체로 한다. 그 결과, 마임 뷰티쇼룸은 공간 디자인과 오감을 융합하여 영상에서 공간에 이르기까지 오감의 조화와 브랜드의 정신을 녹여내고 확장시켰다. 끝으로 본 연구는 뷰티 쇼룸 공간 디자인을 제안함에 있어서 오감을 활용하여 통합된 시점에서 그래픽·제품·공간을 개발 및 제시한 것에 의의가 있다. 또한 향후 이와 관련된 쇼룸 공간 개발에 있어서 기초 자료로 활용될 것으로 기대된다.

형제에서 발견된 단순골낭

안서영,안창현,최갑식 대한구강악안면방사선학회 2008 Imaging Science in Dentistry Vol.38 No.3

17-year-old and 14-year-old brothers were referred for evaluation of the cystic lesions on the mandibular anterior area with no symptoms. Neither their mother nor the brothers could recall any past trauma to those areas. Panoramic and intraoral radiographs revealed moderately defined cystic lesions on their mandibular anterior areas. Biopsies on both lesions revealed simple bone cysts. Hereditary cause or familial history of simple bone cysts could not be found in literature review. This case may have been a coincidence. However, further investigation is needed to find the cause of simple bone cysts occurring in patients those are closely related.

광양만과 여수해만의 표층퇴적물에서 Nonylphenol의 오염에 관한 연구

조현서,김용옥,설순우,-- 한국환경과학회 2004 한국환경과학회지 Vol.13 No.6

This study was carried out to survey the pollution of nonvlphenol (NP) in surface sediments around Gwangyang bay and Yeosu sound. NP was suspected chemicals as endocrine disruption. Gwangyang bay is located on the mid south coast of Korea. It is a semi-closed bay which Yeosu petrochemical industrial complex, POSCO (Pohang Steel Company) and Gwangyang container harbor are there. The surface sediments were collected at 15 stations with gravity corer at October, 1999, February, May and August, 2000. Also, the stream and intertidal sediment were collected at 5 sites at August, 2000. Concentrations of NP in surface sediments were in the range of 6.89 to 202.70 ng/g dry wt.. Seasonal range (mean value) of NP is 13.98 to 30.48 (23.46) ng/g dry wt. at October, 10.35 to 54.91 (28.10) ng/g dry wt. at February, 29.05 to 202.70 (82.32) ng/g dry wt. at May and 6.98 to 83.40 (25.37) ng/g dry wt. at August. NP was seasonally fluctuated, and the highest mean value and range was detected at May, 2000. NP was highly distributed in the inner part of Gwangyang bay than Yeosu sound. Concentrations of NP in stream and intertidal sediments showed the highest value in downstream near Yeosu petrochemical industrial complex and Yondung stream. It suggests that the source of NP is industrial wastewater and municipal sewage.

신지도 동쪽 주변해역의 계절별 수질특성

조현서,윤양호 여수대학교 1997 論文集 Vol.11 No.2

In this study, we discuss on the seasonal fluctuations of water quality and chlorophyll-a in the eastern coastal area of Sinji Island. Sinji Island is located in the eastern part of Wando Island, and the productive farm ground is spread around the Island. Some analytical parameters were analyzed to study the seasonal water quality from Feb. ruary, 4, 1994 to October. 1, 1994 around the Island. The results are as follows: 1) Ranges of pH and suspended solid(SS) were 8.05~8.39 and 0.50~58.08㎎/l, respectively. The highest mean value of SS was 22.47㎎/l in bottom layer at winter season, the lowest mean value was 4.27㎎/l in surface layer at summer season. 2) Dissolved oxygen(DO) concentrations were slightly under saturation in the almost area at fall season, and in some area at summer season. 3) Chemical oxygen demand(COD) concentrations showed the highest mean value of 2.00㎎/l in bottom layer of fall season in the range of 0.66~5.28㎎/l, while showed the lowest mean value of 1.19㎎/l in bottom layer of spring in the range of 0.12~6.80㎎/l. 4) Dissolved inorganic nitrogen(DIN) concentrations showed the highest mean value of 7.17㎍-at./l in both layer at winter season, while showed the lowest mean value of 1.33㎍-at./l in surface layer of summer season. 5) Dissolved inorganic phosphorus(DIP) concentrations were higher at winter season than the other season. And, the the highest mean value of 0.56㎍-at./l was in surface layer at winter season. 6) N/P ratios were lower than 16 of Redfield ratio in both layer at all season except fall. It means that nitrogen is more limiting nutrient than phosphorus in the growth of phytoplankton. 7) Chlorophyll-a concentrations showed the highest mean value of 4.35㎎/㎥ in surface layer at spring season.