• Ocean and Polar Research
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• 제26권1호
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• pp.23-32
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• 2004

As a baseline survey for long-term monitoring on environmental change around the Antarctic King Sejong Station, distribution pattern of Deschampsia antarctica Desv., a flowering plant newly colonized were investigated qualitatively and quantitatively in both austral summer 2002 and 2003. Dispersal of the seeds and vegetative leaves by skuas might lead to the colonization into this area from neighbors in Maxwell Bay. The pioneer populations were observed around ponds and a stream of the Sejong Point in January 2002, and the maximum dispersal area was four times expanded after a year. Most of the populations were formed on the stable and well-drained substrate, which consisted of moss carpet of Sanionia georgico-uncinata (65%) and pebbles (25%), while only a few young individuals were observed on the unstable and watertight silt-sandy area. Especially, S. georgico-uncinata was being effectively utilized as their primary substrate with the soft, coarse and water-contained leaves. Also the perennial mature plants of D. antarctica were mainly formed on the moss carpet rather than pebbles. A few individuals were grown on other mosses of Polytrichastrum alpinum, Bryum pseudotriquetrum, Pohlia cruda, and Conostomum magellanicum and on a liverwort of Cephaloziella varians. We expect that dispersal of D. antarctica and the following succession to grass field will be countinuously and dynamically proceeded in this area, with the characteristics of ecological niche against the initial moss populations, on the similar continuity of environmental conditions. The continuous observations are needed with establishment of database on environmental change of micro-habitats, e.g. the water content and nutrients of soil and the underground temperature and permafrost.

• 대한기계학회논문집B
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• 제35권6호
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• pp.609-615
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• 2011

2차원 채널 내의 수직 평판을 지나는 유동에 대한 이론적 연구를 수행하였다. 수직 평판은 채널의 상하 중앙부에 위치하며, 수직 평판에서 멀리 떨어진 채널 내에는 포아제 유동이 존재한다. 스톡스 근사를 적용하고 고유함수 전개와 점 배열 방법을 사용하여 유동장을 해석하였다. 해석의 결과로 유동 함수와 압력분포식을 구하였으며, 채널의 벽면과 수직 평판에 작용하는 압력 및 전단응력 분포를 계산 하였다. 또한, 수직 평판으로 인해 부가적으로 발생하는 압력 강하와 수직 평판이 받는 힘을 수직 평판 길이의 함수로 계산하였으며, 대표적인 수직 평판의 길이에 대하여 유선과 압력분포도를 도시하였다. 또한, 작은 레이놀즈 수가 유동에 미치는 영향을 알아보기 위하여 레이놀즈 수가 작은 층류유동의 경우에 대하여 수치해석을 수행하였다.

• 터널과지하공간
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• 제15권3호
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• pp.169-176
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• 2005

경기도 광주군에 건설된 상업적 규모의 지하암반 저장고인 '곤지암 지하암반 저장고' 에 대한 약 7년간 운영중에 측정된 결과를 분석하였다. 운영 초기 에 투입되었던 에너지와 저장고 주변의 온도가 안정화된 이후의 에너지를 비교하여 에너지 소비의 변화경향을 분석하였다. 초기 냉동기 설계에 필요한 용량과 저장고 운영에 필요한 냉동기 용량을 비교하여 초기 냉동시스템 설계 시 고려할 점에 대해 논하였다. 7년간 암반 내 지중온도 변화 양상을 분석하여, 암반 내 지하수가 동결될 때에 소요되는 추가적인 에너지에 대해 논하고, 현재 암반온도 분포 상황을 초기의 온도분포를 예측한 FLAC 수치해석 결과와 비교하였다. 냉동기 가동시간에 따른 투입된 열유량과, 2차원, 3차원 수치해석에 의한 열유량을 비교하여 수치해석에 의한 열유량 예측의 정확성에 대해 논하였다.

• Animal Systematics, Evolution and Diversity
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• 제25권3호
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• pp.325-329
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• 2009

Lepomis macrochirus from the family Centrarchidae, commonly known as Bluegill sunfish, is an introduced freshwater fish in Korea that thrives in lakes, ponds, reservoirs and rivers. Since its introduction into Korea in 1969, Lepomis macrochirus has rapidly dispersed out and increased in number almost all over the freshwater ecosystems in Korea. Consequently this species causes a severe ecological problem, threatening native fishes due to its omnivorous foraging behaviors upon fish juveniles and many freshwater invertebrates. To address population genetic structure of L. macrochirus, 74 fish samples from 10 populations were collected and compared for their mitochondrial D-loop control region. As the result we found that the genetic diversity of L. macrochirus is extremely low such as resulting only four haplotypes with a few nucleotide differences among them. Analysis of molecular variance (AMOVA) revealed that the source of population genetic variation is largely retained in the comparisons among individuals within populations, while it is relatively low with slight significance at the highest hierarchical group. This distribution pattern differs from what is expected when biogeography is under the influence of natural geographic barriers such as mountain ranges in Korea. Instead the result is accord with the influential role of random spreading events facilitated by local people for aquaculture and fishing, and subsequent dispersals since its single point of introduction into Korea.

• The Korean Journal of Pain
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• 제11권2호
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• pp.283-287
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• 1998

Background: Recently, pain clinic is attracting attention and interest of both physicians and laymen. It is the purpose of this article to analyze our 10 years' experience to seek and improve better protocol of treating pain. Methods & Materials: We analyzed retrospectively 11,235 patients who visited the clinic during 10 years from 1986 to 1996. Total number of hospital visits was 51,908. Male to female ratio was 35：65(3910：7325). Treatment modalities employed were SGB(stellate ganglion block), TPI(trigger point injection), etc. Results: Yearly distribution showed a gradual upward curve until 1992 and remains in a horizontal pattern thereafter. Of age distribution, 6th decades occupied the largest proportion(27.29%). As of disease entities, Low back pain & lower extremities pain comprised of the majority(34.01%) and the epidural block was most frequently given as a treatment. Conclusion: Pain clinic is improving rapidly as an important part of medical science in Korea and outpatients of clinic are on an increasing trend. So, anesthesiologists should be make every efforts to research for treatment of good quality.

• 한국정밀공학회지
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• 제28권6호
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• pp.745-750
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• 2011

In a hope to better understand the flow and convective heat transfer characteristics inside a ball bearing, air flow between the rolling elements and raceways at high speed bearing rotation is numerically investigated using a simplified inner geometry of bearing and a CFD technique. Flow simulation results reveal the pressure distribution of airflow and the shear stress distribution on the ball surface, of which nonuniformity becomes significant with the increasing rotational speed. Also, the local point of maximum shear stress coincides with the stagnation flow area on the surface of rolling elements. A complex pattern of three-dimensional vortex structures is found in the air flow due to the relative motion of bearing elements and three different types of vortex pairs exist around the rotating and orbiting rolling elements.

• 유통과학연구
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• 제12권9호
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• pp.5-13
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• 2014

Purpose -This study is to measure the effects of retail legislations on small retailers and traditional markets. Research Design, Data, and Methodology - The authors have developed a questionnaire with five hypotheses on the basis of previous research results and six constructs: the improvement of sales volume, the number of customers, the improvement of store traffic, the increase of store staff, business expansion and retail regulation. Furthermore, the research has adopted a five-point Likert-scale technique. In order to increase research reliability as well as validity, the authors have adopted a few different research techniques such as exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). Results - Although existing retail regulations might be better than nothing for now, the degree of retail constraints on large retailers should be strengthened. Furthermore, different legal methods to protect mom and pops are needed. Conclusions - In order to improve the effects of retail restrictions on large retailers, the research indicates that the central government should change a retail policy, that is, introduce new technical ways to keep mom and pops and conventional markets.

• 한국한의학연구원논문집
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• 제4권1호통권4호
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• pp.47-62
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• 1998

We explicate the forming mechanism of Sasang constitution as the principle of energy distribution which is based on the evolutionary hypothesis. The result was obtained as follows: 1. The principle of form-image (形象) in oriental medicine can be explained with the relation between structure and function that a life acquires through the adaptation and evolution. 2. The Sung-jung (性情) in Sasang constitutional medicine can be explained as the strategy for survival or the pattern of adaptation by which an individual or a species lives in this world. 3. The forming mechanism of Sasang constitutional organic phase (臟局) can be explained as the principle of energy distribution which includes three hypothesis (hypothesis of limited resources, hypothesis of preference and hypothesis of effectiveness). 4. It is postulated that the local hemodynamics is one of the most important factors that determine the difference of Sasang constitutional organic function. 5. The relation of metabolic rate, local hemodynamics and thermo-metabolism is inseparable and it is the important point of forming mechanism of Sasang constitution and the diagnosis of pulse.

• 한국가시화정보학회지
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• 제20권2호
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• pp.86-92
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• 2022

Pipe failure due to thermal fatigue and environmental regulations are increasing the importance of pipe monitoring systems in industrial plants. Since most pipe monitoring systems are focus on external crack inspected, it is necessary to temperature and concentration measuring monitoring system inside the pipe. These systems have spatial uncertainty due to sample inspection by one-point measurement. In addition, real-time measurement is not possible due to the limitation of time delay due to contact measurement. In this study, CT-TDLAS (Computed tomography-Tunable diode laser absorption spectroscopy) apply to overcome the limitations of existing methods. Lasers exhibiting an absorption response at a wavelength of 1395 nm were arranged in a lattice pattern on measuring cell. It showed that the inside of the pipe changed to an unstable combustion state over time.

• 전자공학회논문지B
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• 제31B권7호
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• pp.101-107
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• 1994

In this work a scanning capacitance microscopy(SCaM) by stage driving is proposed and presented some of the experimental results.SCaM is a microscope which scans a surface of materials mechanically in two or two point five dimensions by a capacitance probe with a few tenth $\mu\textrm{m}$ ize tip, and display images of the surface shape or capacitive distribution. The present target of the SCaM is 0.1$\mu\textrm{m}$ resolution power which exceeds that of optical microscope. This will become a powerful tool for inspecting ULSI pattern etched by X-ray biological data etc. The experimental system is composed based on a VHD video disk which captures the capacitance changes of the video disk surface and converts it into video signal.