그라프트 중합에 의한 클로로프렌 고무의 물성에 관한 연구

황승순,이상호,손진언,박동원 동아대학교 생산기술연구소 2002 生産技術硏究所硏究論文集 Vol.7 No.1

Graft-copolymerization were performed with poly(chloroprene) and methyl methacrylate (MMA) in order to determined the effects of initiator concentration, reaction time, and nitrogen purging on the kinetics of the copolymerization and physical properties of the copolymer. At high concentrations of initiator poly(chloroprene-graft-methyl methacrylate) is more viscous in case that nitrogen is purged during the copolymerization, compare to the copolymerization under air environment. The conversion of MMA increases with the concentration of initiator while the elongation of the copolymer maintains relatively steady. After the copolymerization elapses around 3 hours with nitrogen purging, the viscosity of the copolymer increases rapidly. However, the viscosity is almost steady regardless of time under air environment. Whereas the conversion of MMA increases with reaction time, the efficiency of grafting decreases. The graft copolymer prepared in air has relativity constant tensile strengths of 200 Kgf/cm2. The copolymer prepared with nitrogen purging has tensile strengths grater than 250 Kgf/cm2 and shows a maximum value, 275 Kgf/cm2, at the reaction time of 2.5 hours. Drying the solvents used to make chloroprene adhesive is faster in order of methyl alcohol, methyl cyclopentane, o-xylene, and cyclohexane.

환경 및 시간경과에 따른 건축용 단열재의 열전도율 변화에 관한 실험적 연구

이승언,강재식,정영선,최현중 대한건축학회 2003 대한건축학회논문집 Vol.19 No.12

The objective of this research is to provide the basic experimental data for thermal insulation design standard of buildings and for test criterion. We tested the thermal conductivity of insulation materials which was the insulation materials in domestic buildings with environmental condition change and long-time elapse. In research, we measured change of thermal conductivity with change of contained water rate by weight, test temperature change and the passage of time. the specimens of insulation materials were kept in test condition, which was influenced by the outside environment during long-time elapse test. The result of the research shows 1)the contained water rate of artificial mineral fiber insulations is higher than others, 2)thermal conductivity rises as test temperature goes up, 3)the thermal conductivity of the extruding insulations and hardened Urethane foam changes with environmental condition and time elapse. As a result, the test methods and standards for thermal conductivity properties have much room for consideration.

CT법을 이용한 진직도 및 직각도 측정에 관한 연구

이승수,김민주,박정보,전언찬 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.1

As high-precision parts are needed with manufacturing techniques improved, the demand of high-precision machine tools has been increasing. They are made to developed the precision measuring skill to maintenance the accuracy of themselves as a matte of course. We on the paper measured straightness and orthogonality of the square to verify that is possible for CT(circular test) method by 2-dimensional probe and the square to measure orthogonality. Furthermore, we compared the result of the study with the computer simulation's to prove its possibility, and made an improvement of measuring method.

Rician 페이딩 채널에서 WATM 셀의 성능 개선에 관한 연구

조성언,박정현,백승선 順天大學校 1998 論文集 Vol.17 No.1

This study has analyzed theoretically the effect of fading to design effective wireless ATM system. The CNR, CLR, and CER of wireless ATM system adopting FEC coding and diversity reception techniques have been derived in fading environment. From the results, CLR in the HFEC which puts more importance on coding gain than coding rate, it show(62, 32, 5)FEC coding having higher coding gain is more adequate. And also, it has to consider CER and MaxU data together in the PFEC performance, because emphasizing the error correction ability to lessen CER cause inefficient use of channel by the added redundancy bit. (438, 384, 6) FEC coding is more appropriate in the CER and MaxU. it is showing the CER and MaxU value when dividing (438, 384, 6) FEC. The more division is the less CER value in the CER, but in the MaxU, when a wires ATM cell is divide by more then two WATM cell, it leads to increase of overhead due to more header transmission, and finally to relatively poor MaxU value in the case of going over the certain bound of CNR value. (240, 192, 6) FEC code is proper than (438, 386, 6) code when considering CER and MaxU data in the payload division. Using diversity technique to wireless ATM cell header improves MRC to about 1.7 dB of Eb/No than SC under the Rayleigh fading environment, and to 2 dB of Eb/No under Rician fading (K=5). Also using the diversity technique to wireless ATM cell Payload under Rician fading environment improves MRC to 3dB of Eb/No than SC in both case of K=5 and K=10.

원호검사법을 이용한 진원도 측정 방법의 개선에 관한 연구

이승수,김민주,전언찬 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.2

A study for the circularity of machine tool is classified into two ways. One is to measure the circularity of machine tool by a existing measuring device. The other is to measure the circularity by remodeling the existing measuring device. We will improve on measurement of circularity using circular test method by a two-dimensional probe and a master ring for machining tools and investigate influence of trigger method, acceleration, data sampling.

공터키안(Empty sella)을 동반한 급성췌장염으로 발현된 부갑상선 선종 1예

전언주,오지혜,배경륜,장샛별,전승운,정의달,손호상,원규장 영남대학교 의과대학 2009 Yeungnam University Journal of Medicine Vol.26 No.1

The incidence of coexisting hyperparathyroidism and empty sella syndrome is rare and the etiology and incidence of their coexistence is not known. The association of hyperparathyroidism and the empty sella syndrome may be related to multiple endocrine neoplasia (MEN) syndrome due to a genetic disorder. We experienced a rare case of hyperparathyroidism presenting as acute pancreatitis combined with empty sella. We report here a 37-year old female who manifested epigastric pain because of acute pancreatitis. She had hypercalcemia due to parathyroid adenoma. A pituitary gland was not visible in the sella turcica on MRI scans. On genetic analysis, she did not show a mutation of the MENIN gene. Empty sella is thought to be a coincidental finding with hyperparathyroidism.

건축에서 지역성의 탈은폐 : 하이데거의 “열린 터”(the Open)와 “틈새내기”(Rift-design) 사유를 바탕으로 Based on the Thought of Heidegger's “the Open” & “Rift-design”

이승헌,이동언 대한건축학회 2003 대한건축학회논문집 Vol.19 No.12

In contemporary architecture, the expression of regionality has been continuously interested and experimented. But there were few theoretical approaches on the meaning of regionality and few authentic explorations for the expression of it. Thus this paper draws out a theoretical frame for regionality from Heidegger's two main thoughts , "the Open" and "Rift-design" and suggests ‘disclosure montage’ as a technique of the practical expression of them in architecture. The ‘creative opening’ of regionality is possible through "Rift-design." And "Gestalt", in other words, disclosure montage, can be created in the "rift" by "the conflict between lighting and concealing in the opposition of the world and earth". An architecturally reactivated images of a region are revealed through the technique of ‘disclosure montage’ as a useful expression strategy of "the Open" and "Rift-design." Finally, in order to verify the above mentioned theory, Steven Hall's works are made into a scrutiny.

국내외 ‘영아’ 관련 연구물의 최근 동향 분석 : 2000년~2013년 발간 논문을 대상으로

이승연,권수현,권연정,김언경,나영이,유주연,최정아 이화여자대학교 교육과학연구소 2015 교육과학연구 Vol.46 No.3

The purpose of this study was to examine research trends in infant research published from 2000 to 2013, in order to understand overall aspects in research topics, methods, and subjects in infant research and to suggest directions for future infant research. A total of 2916 journal articles and theses/dissertations, both domestic and foreign, were selected for the analysis. The findings of this study were as follows: First, for the 14 year period, 737 domestic articles, 634 domestic theses/ dissertations, 1242 foreign articles, and 303 foreign dissertations on infant research were published, and there was a steady increase in the number of articles and theses/dissertations over the years. Second, in terms of research topics, different patterns were found between the domestic ones and the foreign ones; the topic of “education and teachers” in the domestic ones and “development” in the foreign ones occurred most frequently. Third, in terms of research methods, the domestic ones employed “survey” the most, and the foreign ones employed “experiment” the most among quantitative research methods; when analyzing the relation between methods and topics, the foreign ones showed clear matches between topics and research methods, while the domestic ones preferred “survey” regardless of the topics. Fourth, in terms of subjects/participants, “infants” were the most researched in both the domestic ones and the foreign ones, followed by “parent” and “teachers.” Among the infants, the domestic ones focused on 25~36-month olds the most, while the foreign ones focused most on 0~12-month olds. In addition, in all types of infant research, there were more single subject studies than multiple subject ones.

기어의 자동설계와 검증에 관한 연구

한민식,김승현,송호봉,전언찬 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-

Gear is main machine element which is used for the power transmit device when it si short in the gear. We use a standard goods in the case of the gear. But in case of special purpose, we need to manufacture the gear that have different angles. In this paper, we manufactured standard gears using W-EDM and Hobbing machine. We got a 3D shape doing reverse engineering manufactured gears. And then compared CAD data and measured data. Finally we verified ADS through comparing ADS data and KISSsoft data.

호닝 가공에 사용되는 다이아몬드 공구의 성능평가에 관한 연구

김민주,이승수,전언찬 한국공작기계학회 2002 한국생산제조학회지 Vol.11 No.1

This study is to evaluate the tool performance in honing using diamond reamer and present grounds whether the localized products are sufficiently competitive comparing with the existing imported ones. The heads of the tool performance evaluation are roundness, roughness, tool life of the workpiece and so on. When evaluating the tool performance, cutting process is divided by three areas which are rough, semi-finish and finish cut. Honing improves the accuracy such as boring and reaming after manufacturing the inside diameter, and finishing directly by boning is a recent trend. This honing is used greatly in hard cutting materials like cemented carbides and it is the CBN and diamond that is used in hard cutting materials. Both of them are expensive and most of them are imported.