肝細胞의 Cell Cycle과 Circadian Rhythm에 對하여

嚴正燮,李隆昌 최신의학사 1974 最新醫學 Vol.17 No.8

In order to estimate the circadian variation of cell cycle of liver cell 3H-thymidine was introduced into one day postnatal male chicks of Shaver species and autoradiography was carried out. The chickss were divided into two experimental groups; AM and PM groups. At the beginning of every hour, starting from 5:03 AM for 25 hours, 3 healthy chicks were carefully selected and injected with given doses of (3)^H-thymidine to be used as the AM group. PM chickss were treated in the same manner starting from 2:00 PM. AM chicks were sacrificed at 6:00 AM and PM chicks at 3:03 PM next day. The livers of these animals were autoradiographed. These results were analyzed and compared with previous studies. The results were summarized as follows: 1. The duration of TG was 398 hours in AM chicks and 530 hours in PM chicks. 2. The durarion of S phase was 17.5 hours in AM chicks and 10.6 hours in PM chicks. 3. The duration of G2 phase was 2.5 hours in AM chicks and 2.8 hours in PM chicks. 4. The duration of M phase was 1.0 hour in AM chicks and 1.2 hours in PM chicks. 5. The duration of Gl phase was 377 hours in AM chicks and 516 hours in PM chicks. Labelling indices of AM and PM chicks were 4.4% and 2.0% respectively. Difference between the generation times of AM and PM chicks was significant showing the influence of circadian rhythm. Difference between the durations of S phases of AM and PM chicks was significant. Durations of G, phases of AM and PM groups revealed a remarkable difference.

녹피율 훼손추세 평가를 통한 총량규제 근거자료 확보방안

엄정섭 대한공간정보학회 2006 Spatial Information Research Vol.14 No.3

This research is primarily intended to investigate the potential of estimating green space threshold in terms of total volume control using degradation trends of green space derived from remote sensing and GIS. An empirical study for a case study site was conducted to demonstrate how a standard remote sensing and GIS technology can be used to assist in estimating the total control volume for green space in terms of area-wide information, spatial resolution and change detection etc. Guidelines for a replicable methodology are presented to provide a strong theoretical basis for the standardization of factors involved in the estimation of the green space threshold; the meaningful definition of land mosaic, redefinition of degradation trends for green space. It was demonstrated that the degradation trends of green space could be used effectively as an indicator to restrict further development of the sites since the visual maps generated from remote sensing and GIS can present area-wide visual evidences by permanent record. It is anticipated that this research output could be used as a valuable reference to support more scientific and objective decision-making in introducing aggregate control of green space.

Tracheal Wall Thickening Is Associated with the Granulation Tissue Formation Around Silicone Stents in Patients with Post-Tuberculosis Tracheal Stenosis

엄정섭,김호중,전경만,엄상원,고원중,서지영,정만표,권오정 연세대학교의과대학 2013 Yonsei medical journal Vol.54 No.4

Purpose: Tracheal restenosis due to excessive granulation tissue around a silicone stent requires repeated bronchoscopic interventions in patients with post-tuberculosis tracheal stenosis (PTTS). The current study was conducted to identify the risk factors for granulation tissue formation after silicone stenting in PTTS patients. Materials and Methods: A retrospective study was conducted between January 1998 and December 2010. Forty-two PTTS patients with silicone stenting were selected. Clinical and radiological variables were retrospectively collected and analyzed. Results: Tracheal restenosis due to granulation tissue formation were found in 20 patients (47.6%), and repeated bronchoscopic interventions were conducted. In multivariate analysis, tracheal wall thickness, measured on axial computed tomography scan, was independently associated with granulation tissue formation after silicone stenting. Furthermore, the degree of tracheal wall thickness was well correlated with the degree of granulation tissue formation. Conclusion: Tracheal wall thickening was associated with granulation tissue formation around silicone stents in patients with post-tuberculosis tracheal stenosis.

Airborne video as a remote sensor for environmental monitoring of linear infrastructure: a case study and review

엄정섭 대한공간정보학회 2004 Spatial Information Research Vol.12 No.4

At present, environmental monitoring of linear infrastructure is based mainly on field sampling. The 'integrated mapping' approach has received only limited attention from field scientists. The increased environmental regulation of corridor targets has required remote sensing research to develop a sensor or technique for targets ranging from 15 m to 100 m in swath width. In an attempt to identify the optimal remote sensing system for linear targets, an overview is provided of the application requirements and the technology currently available. The relative limitation of traditional remote sensing systems in such a linear application is briefly discussed. It is noted that airborne video could provide, in a cost-effective manner, information required for a very narrow and long strip target utilising the narrow view angle and dynamic stereo coverage. The value of this paper is warranted in proposing a new concept of video infrastructure monitoring as a future research direction in the recognition of sensor characteristics and limitations.

송유관선로의 식생복원 감시를 위한 비디오선형지도화 및 patch dynamics 분석 ( Video Strip Mapping ( VSM ) and Patch Dynamics Analysis for Revegetation Monitoring of a Pipeline Route )

엄정섭 대한지리학회 1998 대한지리학회지 Vol.33 No.3

점탄성유체의 저항 및 열전달 감소현상과 퇴화의 영향에 관한 연구

엄정섭,전찬열,유상신,Eum, C.S.,Jeon, C.Y.,Yoo, S.S. 대한설비공학회 1990 설비공학 논문집 Vol.2 No.1

The drag and heat transfer reduction phenomena and degradation effects of drag reducing polymer solutions which are known as the viscoelastic fluids are investigated experimentally for the turbulent circular tube flows. Two stainless steel tubes are used for the experimental flow loops. Aqueous solutions of Polyacrylamide Separan AP-273 with concentrations from 300 to 1000 wppm are used as working fluids. Flow loops are set up to measure the friction factors and heat transfer coefficients of test tubes in the once-through system and the recirculating flow system. Test tubes are heated by power supply directly to apply constant heat flux boundary conditions on the wall. Capillary tube viscometer and falling ball viscometer are used to measure the viscous characteristics of fluids and the characteristic relaxation time of a fluid is determined by the Powell-Eyring model. The order of magnidude of the thermal entrance length of a drag reducing polymer solution is close to the order of magnitude of the laminar entrance length of Newtonian fluids. Dimensionless heat transfer coefficients of the viscoelastic non-Newtonian fluids may be represented as a function of flow behavior index n and newly defined viscoelastic Graetz number. As degradation continues viscosity and the characteristic relaxation time of the testing fluids decrease and heat transfer coefficients increase. The characteristic relaxation time is used to define the Weissenberg number and variations of friction factors and heat transfer coefficients due to degradation are presented in terms of the Weissenberg number.

원형관속을 유동하는 점탄성 유체의 입구 영역 열전달 특성에 관한 연구

엄정섭,황태성,유상신 대한기계학회 1989 대한기계학회논문집 Vol.13 No.5

본 연구에서는 해석적으로 열적 입구 길이를 규명하는데 필요한 와류 열확산 계수를 실험 결과를 이용하여 결정하고, 시험관 입구의 형상 변화가 열전달 특성에 미치는 영향을 실험적으로 결정하며, 열적 입구 길이 영역에서 국소 열전달 계수를 표시할 수 있는 실험식을 제시하고, 유체의 전단율에 따른 점성 계수의 실험 결과와 점탄성 유체의 특성시간을 이용한 새로운 무차원 수인 Weissenberg수를 결정하여 퇴화 현상을 분석하고저 한다. The heat transfer characteristics of the drag reducing polymer solutions are investigated experimentally in the thermal entrance region of circular tube flows. Fluids used in experiments are the aqueous solutions of high molecular polymer, polyacrylamide Separan AP-273 and the range of polymer concentrations is from 20 to 1000 wppm. Two stainless steel tubes with inside diameter 8.5mm(L/D=712) and 10.3mm(L/D=1160) are used for the heat transfer flow loops. The flow loop is set up to measure friction factors and heat transfer coefficients of test sections in two different modes; the recirculating flow system and once-through flow system. The test tubes are heated directly by electricity to apply the constant heat flux boundary conditions to the wall. Three different types of adaptors are used to observe the effects of the upstream flow conditions of the heat transfer test sections. The viscosity and characteristic relaxation time of the test fluids circulating in the flow system are measured by the capillary tube viscometer and falling ball viscometer at regular time intervals. The installed adaptors exhibit slight effect on the entrance heat transfer of Newtonian fluid. However, no noticeable effects are observed for the entrance heat transfer of the drag reducing fluids. The order of magnitude of the thermal entrance lengths of the drag reducing fluids which follow the minimum friction asymptote is much longer than that of Newtonian fluids in turbulent flows. A new dimensionless parameter, the viscoelastic Graetz number, is defined and all the experimental data are recasted in terms of the viscoelastic Graetz number. The local Nusselt number of the viscoelastic fluids is represented as a function of flow behavior index n and the viscoelastic Graetz number. As degradation continues the viscosity and the characteristic relaxation time of the testing fluids decrease. Weissenberg number defined by the relaxation time and D/V appears to be a proper dimensionless parameter in describing degradation effects on heat transfer of the viscoelastic fluids.

시스템 다이내믹스 관점에서 환경영향평가의 재구조화 가능성 평가 : 이론적 고찰 Theoretical Review

엄정섭 경북대학교 사회과학대학 지리학과 2005 地理學論究 Vol.- No.24

본 연구는 시스템 다이내믹스(System Dynamics: SD)를 활용하여 환경영향평가의 질을 개선할 수 있는 방안을 제시하고자 수행되었다. 먼저 시스템 다이내믹스가 어떤 방식으로 환경영향평가와 연계되어 활용될 수 있는 지를 설명하는 방법론적인 고찰이 이루어졌다. 시스템 다이내믹스의 대두배경, 시스템 사고, 인과지도, 유량-저량 흐름도, 그래프를 통한 동태성 재현 등의 개념이 제시되었다. 본 개념의 타당성을 검증하기 위해 사례연구지역에 대한 ESDA(Environmental System Dynamics Assessment)가 시도되었다. This paper is intended to propose new concepts for evaluating environmental impact in terms of system dynamics (SD) point of view. The methodological review describes how SD could be integrated into the formal EIA system. The reader is first introduced to an overview of the basic concepts and principles of SD, followed by system thinking, feedback system analysis, stock/flow diagram, dynamic representation by graph model. An empirical study for a case study site has been conducted to confirm the validity for the ESDA (Environmental System Dynamics Assessment) approach. The author believes that the ESDA would play a crucial role in improving the quality of EIS(Environmental Impact Statement) since the highly user-friendly interface provides a completely new means for forecasting environmental impact for area-wide landscape in a visual and interactive manner. As a result, the research findings have established the new concept of "ESDA toward the quality assurance of the EIA", proposed as an initial aim of this paper.

Monitoring negotiation strategy for Forestry Voluntary Carbon Market with North Korea

엄정섭 대한공간정보학회 2016 Spatial Information Research Vol.24 No.5

South Korea launched a national carbon-trading scheme (including forestry carbon offsets) in January 2015 to stimulate corporate efforts in reducing carbon emission. South Korean enterprises are under an obligation to search for offset forests, and North Korean forests represent a potential option. This study begins by identifying whether satellite imagery could be used for Forestry Voluntary Carbon Market in North Korea by interdisciplinary interpretation. Close interaction between social science and remote sensing discipline examined negotiation monitoring target such as government failure for deforestation control and calculating opportunity cost, and seek out matches between the technical capabilities of satellites and monitoring negotiation requirements. The second part of this study presented referential variables, stakes and chips of negotiation such as measurement, reporting and verification enforcement methodology, types of forest carbon markets and human rights-based approach as springboards to prepare for intergovernmental dialogue with North Korea. This research could be a valuable reference for utilizing the capabilities of satellites in monitoring negotiation with North Korea by suggesting realistic interdisciplinary interaction between remote sensing and social Science.

Web GIS를 이용한 수요자 중심의 하천수질 정보시스템 구현

엄정섭,신소은 대한공간정보학회 2002 Spatial Information Research Vol.10 No.1