지중내 공동 탐지를 위한 비파괴 검사 기법에 대한 실험적 연구

유정동(Jund Dong?Yoo),양학모(Hak Mo?Yang),장기창(Ki Chang?Jang),강승민(Seung Min?Kang),조소현(So Hyun?Cho),김현기(Hyun-Ki?Kim),Seung Soo?Kim,Da Bin?Jin 대한토목학회 2018 대한토목학회 학술대회 Vol.2018 No.10

과재하중 재하에 따른 역 T형 옹벽의 활동거동에 관한 수치해석

유남재,이명욱,박병수,이승주 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

This paper is experimental and numerical research about the sliding behavior of cantilever retaining walls resisting surcharge loads. In experimental research, centrifuge model tests at the 1g and 40g-level were performed by changing the location of model footing and its width. Bearing capacity of model footing and characteristics of load-settlement and load-lateral displacement of retaining wall were investigated. Test results of bearing capacity were compared with modified jarquio method, based on the limit equilibrium method with elasticity theory. For the numerical analysis, the commericially available program of FLAC was used by implementing the hyperbolic constitutive relationships to compare with test result about load-settlement and load-displacement of retaining wall, bearing capacity of strip footing.

모래다짐말뚝의 원심모델링

유남재,정길수,김상진,채승호 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.B

This paper is results of extensive centrifuge model experiments about design factors influencing the bearing capacity and the settlement behaviors of SCP (Sand Compaction Pile). Centrifuge model tests were carried out changing design factors for SCP method such as replacement area ratio (as= 20, 40, 70%), improvement ratio to footing width (W/B = 1, 2, 3), and amount of fines in sand pile (#200 = 5, 10, 15). Therefore, the effects of these design factors on the bearing capacity and the settlement behavior of SCP were investigated and changes of stress concentratio rato due to such an design factors were also investigated. Centrifuge model testing technique for preparing and installing centrifuge model of sand compaction pile, using freezing them, was also developed. As results of centrifuge model tests, more fines in sand compaction pile increases the bearing capacity of SCP. Optimum improvement ratio to footing width was found to be 2. Values of stress concentration ratio was in the ranges of 1.5 - 3.5. The depth of bulging in sand piles was found in the range of 2.0 - 2.5 times of pile diameter.

Self-etching priming/bonding agent를 이용한 수복에서 microleakage에 관한 연구

유승훈,김종수 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.1

Bonding Agent는 1세대에서 5세대에 거치기까지 많은 발전을 하였고, 최근에는 임상술식과정의 단축에 있어 비약적인 발전을 보였다. 최근에 개발되어 소개된 self-etching pyirning/bonding agent는 6세대 bonding agent로 분류되며, 이를 이용하여 법랑질 및 상아질에 대한 복합 레진의 충전시 발생하는 미세누출을 methylene blue를 이용하여 관찰한 결과, 상아질에서는 기존의 4세대 5세대 접착제와 유의한 차이가 없었으나, 법랑질에서는 6세대 bonding agent가 통계학적으로 높은 미세누출 양상을 보였다. Self-etching priming bonding system was recently developed in order to simplify the clinical skills & save chair time after continuous improvements on dentin bonding agents. To test the magnitude of microleakage of a new "self-etching priming bonding agent" using sound premolar, 4th, 5th, 6th generation dentin bonding agent was applied. Measure the magnitude of infiltration to the gap of enamel-restoration interface and dentin-restoration interface. After bonding of composite resin to sample surfaces according to the manufactures direction and 500 times thermocycling en dwell time 30 second, and microleakage was measured by the ratio of the depth to the axial wall and the magnitude of infiltration. Afterward analyzed by ANOVA test. The result were as follows : 1. Enamel groups showed lesser microleakage (Group Ⅰ, Ⅱ, Ⅲ, Ⅳ) than dentin groups (Group Ⅴ, Ⅵ, Ⅶ, Ⅷ). (p<0.05) 2. There are no statical differences among the dentin groups, in enamel groups, group Ⅳ showed more microleakage than group Ⅰ, Ⅱ, Ⅲ. (p<0.05) For a clinical acceptance, better enamel marginal adaptation is required.

다종의 Pulse Oximeter에서 측정된 산소 분압도의 차이와 상호 비교 결과에 대한 보고

유승훈,김응학,권순원,김종수 대한소아치과학회 2000 大韓小兒齒科學會誌 Vol.27 No.4

진정요법하의 치과치료에서 환자의 상태를 지속적으로 감시하는 것은 매우 중요하다. 여러 방법 중 가장 널리 사용되는 것중 Pulse Oximeter가 있다. Pulse Oximeter는 비침습적 방법으로 계속해서 동맥혈액의 산소포화도를 측정할 수 있도록 고안된 장치로서 기기에 나타나는 산소포화도(SpO₂)는 실제로 측정한 동맥혈액의 산소포화도(SaO₂)와 거의 일치하는 것으로 알려져 있다. 본 진료실에 있는 세종류의 Pulse Oximeter를 이용하여 한 환자에게 동시에 두 개의 기기를 적용하였을 경우, 산출값을 상호 비교한 결과, 짧은(3회) 맥박수를 평균하는 기기가 낮은값이 나왔으며, 다른 두개의 Pulse Oximeter와 유의한 차이가 있는 것으로 밝혀졌다. 짧은 맥박수를 평균하는 기기는 반응이 빠르나, 산소포화도의 값이 작게 산출되고, 외부의 신호에 더욱 민감하여, 오류가 존재할 가능성 또한 높다. 기기의 특성을 알아, 술자는 적절한 기기를 선택하는 것이 중요하다. A major concern in pediatric dentistry is maximizing risk mangement through optimal monitoring of respiratory function during sedation techniques, and Pulse Oximeter is one of the most popular devices for these purpose. Pulse Oximeter is non-invasive device for detecting the sensitive fraction between the saturated & desaturated hemoglobin. Several Studies proved that there is no significant difference between the SpO2 and SaO2 . In this article, We examined three Pulse Oximeter (3300MXR, OX90R, BPM200R). The Pulse Oximeter using shorter pulse beat averaging showed more sensitive reaction to the statue of the patient and lower saturation data. We compared pair of Pulse Oximeter applied to one patient at one time. And BPM200R (using shorter pulse beat averaging) showed statistically low saturation

심부정맥혈전에서 조영증강 FISP 기법을 이용한 자기공명술의 유용성

유정현,최수승 梨花女子大學校 醫科大學 醫科學硏究所 1999 EMJ (Ewha medical journal) Vol.22 No.3

Objectives: To demonstrate a number of advantages of Gd-enhanced MR-venography with FISP techinuque in diagnosis of extremity deep vein thrombosis. Method and Materials: Gd-enhanced MR venography with FISP technique was performed in patients had deep venous thrombosis of lower limb. Findngs of MR venography was retrogradely analyzed. Results : Gd-enhanced MR-venography clearly demonstrates venous anatomy of the lower extremities in all cases. And, deep vein thrombosis was well detected with signal void filling defect. MR-venography also shows additional combined findings in deep vein thrombosis. Conclusion : Gd-enhanced MR venography well demonstrates the anatomy of lower extremities and is a useful method for detection of deep vein thrombosis.

데이타흐름 시스템에서의 성능평가에 관한 연구

유관종,최종석,신지수,변승환 충남대학교 자연과학연구소 1989 忠南科學硏究誌 Vol.16 No.1

A concept of data flow computer is a radical departure from that of Von Neumann type computers since the central concept of sequential execution is discarded. Data flow model offers an entirely new way of view the execution of program. This paper describes the data flow graph partitioning algorithm for enhancing the efficiency of the data flow architecture which consists of Processing Elements, Distributor, Arbitrator and Global Memory, and evaluate the performance of the proposed data flow system.

Cellulose 생합성 세균의 분리 및 특성

이승진,유주순,정수열,최용락 東亞大學校附設遺傳工學硏究所 1998 遺傳工學硏究 Vol.- No.5

발효시켜서 만드는 감식초에서 시료를 채취하여 배양하고, pellicle을 형성하는 single colony를 cellulose생합성균으로 분리하였다. 분리된 균주는 형태적 특성, 알콜의 재산화 등의 생리, 생화학적 특성 등에 의하여 Acetobacter속으로 분류되었으며, Acetobacter CBI-2라고 명명하였다. Acetobacter CBI-2는 정지배양 시에 기존의 생합성 균주로 알려진 Acetobacter xylinum과 대등한 cellulose생합성 능력을 나타내었다. Acetobacter CBI-2이 생성한 고분자물질의 분해산물을 TLC법으로 확인한 결과 기존 cellulose의 것과 일치하였다. Acetobacter CBI-2에서 genomic DNA를 분리 정제하여 cel A 영역을 probe로 하여 hybridization시킨 결과, 상동성을 나타내어 분리 균주에는 cellulose 생합성 관련 유전자가 존재함을 나타내었다.(1997년 1월 7일 접수, 1997년 2월 24일 수리). A screening was performed to isolate the cellulose-producing microorganisms from vinegar in Korea. The isolated strain was identified as Acetobacter sp. with respect to physiological and biochemical characteristics and designated as Acetobacter CBI-2. Cellulose production of Acetobacter CBI-2 was equal with the well known cellulose-producing bacteria, A.xylinum. The result of separation on thin layer chromatography (TLC) was consistent with the degradation product of native cellulose. The presence of genes required for the cellulose biosynthesis in Acetobacter CBI-2 was confirmed by Southern hybrization.

수종의 수복재의 불소 적용법에 따른 불소 유리에 관한 비교 연구

김종수,이연호,유승훈 大韓小兒齒科學會 2006 大韓小兒齒科學會誌 Vol.33 No.1

불소는 구강내에서 치아 우식의 예방 및 초기 우식의 재광화를 유도하기 위한 목적으로 널리 사용되고 있으며, 불소가 유리되는 수복물을 이용하게 되면, 수복물 주위의 이차 우식 및 구강내의 우식 감수성을 감소시킬 수 있다. 현재 소아치과 영역에서 주로 사용되고 있는 불소유리 수복재로는, 전통적인 글라스 아이오노머와 레진 강화형 글라스 아이오노머, 컴포머 등이 있는데, 본 연구에서는 현재 소아치과 영역에서 많이 사용되고 있는 불소를 유리하는 수복재의 불소 유리량 및 불소 적용방법에 따른 불소유리량의 변화를 비교하여 확인하고자 한다. 복합레진으로 Z-250™(Group Ⅰ)과 컴포머로 Dyract^(®) AP(GroupⅡ), 레진 강화형 글라스 아이오노머로 Fuji Ⅱ LC^(®)(Group Ⅲ), 자가중합형 글라스 아이오노머로 Fuji ⅨGP Fast^(®)(Group Ⅳ)를 실험대상으로 선정하였다. 각 재료별로 동일한 크기의 디스크를 제작하여, 31일 동안 매일 새로운 용액으로 교환하면서 불소 유리량을 측정하였다(실험 Ⅰ), 이후 수복 재료별로 불소 적용 방법에 따라 4군으로 나누는데, A군은 대조군(No treatment)으로, B군은 불소가 함유된 치약(500ppm, Stages, Oral-B^(®),Holland)을 3분간 3회 적용하고, C군은 1.23% APF Foam(1000ppm, Sultan Topex,#31150,Canada)을 1회 적용하며, D군은 B군과 동일한 치약을 3회 적용하고, 1.23% APF Foam을 1회 적용하였다. 불소 적용 후 7일 동안 불소 유리량을 측정하였다(실험Ⅱ). 실험 Ⅰ에서, 실험 개시일부터 7일까지 불소 유리량이 급속히 감소하고, 이후 일정한 불소 유리량을 보였다. Ⅲ군 (Fuji Ⅱ-LC^(®))과 Ⅳ군 (Fuji ⅨGP Fast^(®))이 다른 군에 비해 높은 불소 유리량을 보였으며,Ⅲ군과Ⅳ군 사이에서는 유의한 차이를 보이지 않았다. 실험 Ⅱ에서, 불소 적용 후 Ⅱ,Ⅲ,Ⅳ군에서 불소 유리량이 증가한 양상을 보이는데,Ⅱ군에서는 불소 적용 후 2일, Ⅲ군에서는 5일,Ⅳ군에서는 4일부터 초기 불소 유리량 수준으로 돌아갔다. Fluoride released from dental restorative materials effectively declines the incidence and activity of dental caries and inhibits tooth demineralization. This study investigated the fluoride release and uptake characteristics of one composite resin (Z-250™)three glass ionomer-based restorative material (Dyract AP, Fuji Ⅱ LC^(®),Fuji Ⅸ GP Fast^(®)),Forty discs(6 mm diameter and 1 mm height) were prepared for each material. Each disc was immersed in 5ml of distilled water within polyethylene vial and stored at 37℃. The distilled water was changed every 24 hours and the release of fluoride was measured for 31 days. At the end of this period. each specimen was subjected to one of four treatments : (A) no fluoride treatment (control) : (B) application of a fluoride dentifrice (500ppm) for three minutes three times : (C) application of the 1.23% acidulated phosphate fluoride(APF) foam for one minute once: (D) the same regimen as (B), plus application of the APF foam for one minute once. Then, all samples were reassessed for an additional 7 days. For all samples, the greatest fluoride release was observed after the first day of the study but diminished with time. On the 7th day of the study. fluoride release level was stabilized. Fuji ⅡLC^(®) and fuji ⅨGP Fast^(®) released higher amount of fluoride than other materials: however no statistically significant difference was found from Fuji Ⅱ LC^(®) and Fuji Ⅸ GP Fast^(®). The amount of fluoride of Dyract^(®) AP Fuji ⅡLC^(®) and Fuji ⅨGP Fast^(®) was increased after fluoride treatment, and diminished with time.

부착성 동물세포의 Scale-up을 위한 방법의 개발

김승모,송상호,최명락,유은정,임현수 여수대학교 1997 論文集 Vol.11 No.2

This study was a protocol of serial propagation for anchorage-dependent animal cell. Vero. by the optimization of trypsin and EDTA concentration in T-25 flask. Commen enzymetic treatment in PBS solution has been modified for a high degree of cell datachment from T-25 flask and for transfer of a maximum number of viable cells from one culture to the next during the scale up process. Culture of Vero cells were washed with Dulbecco's modified Eagle's medium(DMEM) and then exposed to DMEM containing trypsin(0.025%) and EDTA(0.16%). Up to 90% of cells detached from bottom of flask and the viability of cells was greater than 93%. The protocol using the developed method was successfully applied to the next 10 times scale up process. Consequently, the developed method changed multiple steps of processes to one step, so it promised th easy scale-up and low cost demand of animal cell culture.