• Title/Summary/Keyword: 일반단면

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Properties of the interfacial oxide and high-k dielectrics in $HfO_2/Si$ system ($HfO_2/Si$시스템의 계면산화막 및 고유전박막의 특성연구)

  • 남서은;남석우;유정호;고대홍
    • Proceedings of the Korea Crystallographic Association Conference
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    • 2002.11a
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    • pp.45-47
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    • 2002
  • 반도체 소자의 고집적화 및 고속화가 요구됨에 따라 MOSFET 구조의 게이트 절연막으로 사용되고 있는 SiO₂ 박막의 두께를 감소시키려는 노력이 이루어지고 있다. 0.1㎛ 이하의 소자를 위해서는 15Å 이하의 두께를 갖는 SiO₂가 요구된다. 하지만 두께감소는 절연체의 두께와 지수적인 관계가 있는 누설전류를 증가시킨다[1-3]. 따라서 같은 게이트 개패시턴스를 유지하면서 누설전류를 감소시키기 위해서는 높은 유전상수를 갖는 두꺼운 박막이 요구되는 것이다. 그러므로 약 25정도의 높은 유전상수를 갖고 5.2~7.8 eV 정도의 비교적 높은 bandgap을 갖으며, 실리콘과 열역학적으로 안정한 물질로 알려진 HfO2[4-5]가 최근 큰 관심을 끌고 있다. 본 연구에서는 HfO₂ 박막을 실제 소자에 적용하기 위하여 전극 및 열처리에 따른 HfO₂ 박막의 미세구조 및 전기적 특성에 관한 연구를 수행하였다. 이를 위해, HfO₂ 박막을 reactive DC magnetron sputtering 방법으로 증착하고, XRD, TEM, XPS를 사용하여 ZrO₂ 박막의 미세구조를 관찰하였으며, MOS 캐패시터 구조의 C-V 및 I-V 특성을 측정하여 HfO₂ 박막의 전기적 특성을 관찰하였다. HfO₂ 타겟을 스퍼터링하면 Ar 스퍼터링에 의해 에너지를 가진 산소가 기판에 스퍼터링되어 Si 기판과 반응하기 때문에 HfO₂ 박막 형성과 더불어 Si 기판이 산화된다[6]. 그래서 HfO₂같은 금속 산화물 타겟 대신에 순수 금속인 Hf 타겟을 사용하고 반응성 기체로 O₂를 유입시켜 타겟이나 시편위에서 high-k 산화물을 만들면 SiO/sub X/ 계면층을 제어할 수 있다. 이때 저유전율을 갖는 계면층은 증착과 열처리 과정에서 형성되고 특히 500℃ 이상에서 high-k/Si를 열처리하면 계면 SiO₂층은 증가하는 데, 이것은 산소가 HfO₂의 high-k 박막층을 뚫고 확산하여 Si 기판을 급속히 산화시키기 때문이다. 본 방법은 증착에 앞서 Si 표면을 희석된 HF를 이용해 자연 산화막과 오염원을 제거한 후 Hf 금속층과 HfO₂ 박막을 직류 스퍼터링으로 증착하였다. 우선 Hf 긍속층이 Ar 가스 만의 분위기에서 증착되고 난 후 공기중에 노출되지 않고 연속으로 Ar/O₂ 가스 혼합 분위기에서 반응 스퍼터링 방법으로 HfO₂를 형성하였다. 일반적으로 Si 기판의 표면 위에 자연적으로 생기는 비정질 자연 산화막의 두께는 10~15Å이다. 그러나 Hf을 증착한 후 단면 TEM으로 HfO₂/Si 계면을 관찰하면 자연 산화막이 Hf 환원으로 제거되기 때문에 비정질 SiO₂ 층은 관찰되지 않았다. 본 실험에서는 HfO2의 두께를 고정하고 Hf층의 두께를 변수로 한 게이트 stack의 물리적 특성을 살펴보았다. 선증착되는 Hf 금속층을 0, 10, 25Å의 두께 (TEM 기준으로 한 실제 물리적 두께) 로 증착시키고 미세구조를 관찰하였다. Fig. 1(a)에서 볼 수 있듯이 Hf 금속층의 두께가 0Å일때 13Å의 HfO₂를 반응성 스퍼터링 방법으로 증착하면 HfO₂와 Si 기판 사이에는 25Å의 계면층이 생기며, 이것은 Ar/O₂의 혼합 분위기에서의 스퍼터링으로 인한 Si-rich 산화막 또는 SiO₂ 박막일 것이다. Hf 금속층의 두께를 증가시키면 계면층의 성장은 억제되는데 25Å의 Hf 금속을 증착시키면 HfO₂ 계면층은 10Å미만으로 관찰된다. 그러므로 Hf 금속층이 충분히 얇으면 플라즈마내 산소 라디칼, 이온, 그리고 분자가 HfO₂ 층을 뚫고 Si 기판으로 확산되어 SiO₂의 계면층을 성장시키고 Hf 금속층이 두꺼우면 SiO/sub X/ 계면층을 환원시키면서 Si 기판으로의 산소의 확산은 막기 때문에 계면층의 성장은 억제된다. 따라서 HfO₂/Hf(Variable)/Si 계에서 HfO₂ 박막이 Si 기판위에 직접 증착되면, 순수 HfO₂ 박막의 두께보다 높은 CET값을 보이고 Hf 금속층의 두께를 증가시키면 CET는 급격하게 감소한다. 그러므로 HfO₂/Hf 박막의 유효 유전율은 단순 반응성 스퍼터링에 의해 형성된 HfO₂ 박막의 유전율보다 크다. Fig. 2에서 볼 수 있듯이 Hf 금속층이 너무 얇으면 계면층의 두께가 두꺼워 지고 Hf 금속층이 두꺼우면 HfO₂층의 물리적 두께가 두꺼워지므로 CET나 EOT 곡선은 U자 형태를 그린다. Fig. 3에서 Hf 10초 (THf=25Å) 에서 정전 용량이 최대가 되고 CET가 20Å 이상일 때는 high-k 두께를 제어해야 하지만 20Å 미만의 두께를 유지하려면 계면층의 두께를 제어해야 한다.

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Effects of Local Climatic Conditions on the Early Growth in Korean White Pine (Pinus koraiensis Sieb. et Zucc.) Stands -Relation between Annual Increment and Local Climatic Conditions- (지역별 잣나무 초기생장에 미치는 미기후의 영향 - 연년생장과 미기후와의 관계-)

  • Chon Sang- Keun;Shin Man Yong
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.1 no.1
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    • pp.41-51
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    • 1999
  • This study was conducted to investigate the effects of local climatic conditions on the annual increment of Korean white pine planted in Gapyung and Yaungdong. For this, stand variables such as mean DBH, mean height, basal area per hectare, and volume per hectare by stand age were measured and summarized for each locality. Based on these statistics, annual increments for 8 years from stand age 10 to 18 were calculated for each of stand variables. A topoclimatological technique which makes use of empirical relationships between the topography and the weather in study sites was applied to produce normal estimates of monthly mean, maximum, minimum temperatures, relative humidity, precipitation, and hours of sunshine. Then, the yearly climatic variables from 1990 to 1997 for each study site were derived from the spatial interpolation procedures based on inverse- distance weighting of the observed deviation from the climatic normals at the nearest 11 standard weather stations. From these estimates, 17 weather variables such as warmth index, coldness index, index of aridity etc., which affect the tree growth, were computed on yearly base for each locality. The deviations of measured annual increments from the expected annual increments for 8 years based on yield table of Korean white pine were then correlated with and regressed on the yearly weather variables to examine effects of local climatic conditions on the growth. Gapyung area provides better conditions for the growth of Korean white pine in the early stage than Youngdong area. This indicates that the conditions such as low temperature, high relative humidity, and large amount of precipitation provide favor environment for the early growth of Korean white pine. A ccording to the correlation and regression an analysis using local climatic conditions and annual increments, the growth pattern of Gapyung area corresponds to this tendency. However, it was found that the relationship between annual increments and local climatic conditions in Youngdong area shows different tendency from Gapyung. These results mean that the yearly growth pattern could not sufficiently be explained by climatic conditions with high variance in yearly weather variables. In addition, the poor growth in Youngdong area might not only be affected by climatic conditions, but also by other environmental factors such as site quality.

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Evaluation of Psychosocial Impact and Quality of Life in BRCA Mutation Family (BRCA 돌연변이 가계의 심리상태 및 삶의 질 평가)

  • Han, Sang-Ah;Kim, Sai-Rhee;Kang, Eun-Young;Kim, Jeong-Hyun;Ha, Tae-Hyeon;Yang, Eun-Joo;Lim, Jae-Young;Han, Won-Shik;Noh, Dong-Young;Kim, Sung-Won
    • Journal of Genetic Medicine
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    • v.7 no.1
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    • pp.67-77
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    • 2010
  • Purpose: The aims of this study are to evaluate psychological impact and quality of life according to the cancer diagnosis and mutation status in Korean families with BRCA mutations. Materials and Methods: Seventeen affected carriers (AC), 16 unaffected carriers (UC) and 13 healthy non carriers (NC) from 13 BRCA mutation families were included in the study. Outcomes were compared with regard to depression (Beck Depression Inventory), anxiety (State-Trait Anxiety Inventory, STAI), optimism (Reevaluation of the Life Orientation test, LOT-R), knowledge of hereditary ovarian cancer, and quality of life (QoL) (SF-36v2 Health Survey, physical component score [PCS], mental component score [MCS]) among three groups. Result: Level of depression, optimism, and PCS were similar in AC, UC, and NC. Anxiety score was elevated in all three groups. MCS was significantly low in AC than in UC and NC (P=0.009, P=0.017). Knowledge of hereditary breast and ovarian cancer was high in AC than NC (P=0.001). MCS was significantly related to whether patient was affected by cancer (P=0.043) and has occupation (P=0.008) or not in multivariable analysis. Conclusion: From this cross sectional study, psychological adverse effect was not related to the carrier status of BRCA mutation. Elevated anxiety in BRCA family members was observed but, independent to affection and the type of genetic mutation. AC showed low mental QoL. Further effort to understand psychological impact and QoL of genetic testing in BRCA family members is required for follow-up in clinical aspects.

A Study on the Spatial and Visual Composition of Yi Ung-Jae's Old House, Dundeok-ri (둔덕리 이웅재고가(李雄宰古家)의 공간 및 경관 구성적 특성에 관한 연구)

  • Rho, Jae-Hyun;Lee, Jung-Han
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.38 no.2
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    • pp.60-76
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    • 2020
  • The purpose of this study was to examine the spatial and visual arrangement characteristics of Imsil Yi Ung-jae's old house's spatial and visual aspects in order to discover the value of landscape and traditional house garden. The results of this study are as follows. Dongchon-village in Dundeok-ri, where old house is located, is a typical form of with "Back to the mountain and facing the water(背山臨水)", and is located in the north of the three streams of water, forming a Jeonchaghugwan(前窄後寬). Dongchon Village, which has a traditional scenic spot between Danguidae(丹丘臺) and Samgyeseokmun(三溪石門), is understood to be the main street of Nojeokbong Peak and Gyegwanbong Peak, which is Ansan(案山), where the "A centipede flying in the sky(飛天蜈蚣形)". Yi Ung-jae's old house is the oldest existing high-priced house in the North Jeolla region and the closing price of a royal family of the Joseon Dynasty, which was arranged by Chunseongjeong(春城正), Yi Dam-son(李聃孫) in the mid-16C. The Japanese Invasion of Korea in 1592 and Japanese colonial era, the loyalty of the gate quarters, the filial piety of the gate quarters, and the faithfulness of the tablet(扁額) and Juryeons(柱聯) are enough to contribute to the rise of the value of a physical house. The men's quarters(Sarangchae), which are placed on a high-pocket or a layout without going against the sloping terrain, have the effect of making the distance as far as possible, enhancing its dignity and hierarchy as a royal building. In addition, the entrance to the main quarters(Anchae) through the four pillar gates(四柱門), the extensive support and the appropriation of the Chaewon(vegetable garden), and the official base for the Anchae are very unique compared to the general nobility. However, in the context of the postwar relationship, the shrine seeks to realize Confucian ideals while harmonizing with nature by arranging wide sponsorships around it. On the other hand, it is confirmed that there was a pond in the form of a circle in a square(方池圓島型) with a relatively large area, which is now disturbed and damaged. Written by the high priced planting species are sponsored pine trees, hackberry, persimmon trees, Japanese apricot flower, Ohmomiji, and plum tree in the side garden, as well as cotyledon trees in the outside garden. However, although flower bed(花階), which is built on the stone axis, is a place that clearly shows the expensive garden, it seems to have lost the texture of the plant due to the extremely high variety of species and the splendor that does not match the plant landscape of the flower world. Yi Ung-jae's old house is highly valuable as it is a portrait house of a prince of the blood in the mid-Joseon Dynasty. Based on these findings, this study proposed a plan to improve the management of high prices that could be met.

A Study on the Characteristic and Manufacture Technique for the Gold wire of Phoenix-Shaped Glass Ewer by National Treasure No. 193 (국보 제193호 봉수형유리병 금사의 특성과 제작기법 연구)

  • Hwang, Hyun Sung;Yun, Eun Young
    • Journal of Conservation Science
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    • v.31 no.1
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    • pp.21-27
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    • 2015
  • The Phoenix-shaped Glass Ewer, which is No. 193 National Treasure, was seriously damaged by a unique form of green glass pieces when excavated among a number of burial accessories of Hwangnamdaechong known to have been formed in the 5th century. While it has long been exhibited at the National Museum of Korea since its treatment for conservation treatment at conservation science laboratory in 1984, the existing adhesive materials seriously deteriorated for the 30 years, and the condition was quite unstable. The epoxy resin used as a restorative materials turned yellowing due to the light and heat so much that it was no longer able to exhibit it in a stable and effective manner. As a result, a re-treatment for conservation was conducted lately. This study focuses on the three pieces of Gold wires used to carefully wrap up the handle of the Phoenix-shaped Glass Ewer broken into three pieces, which has not been studied so far. As for the analysis method for Gold wires, SEM-EDS and Stereo Microscope were used for nondestructive analysis. First of all, the result of the SEM-EDS analysis shows that the composition was Au 91.9 wt.%-Au 92.8 w.t% and Ag 5.9 wt.%-Ag 6.5 wt.%, which indicates that it was an alloy made of Au and Ag. The production technique of Gold wires was also observed by means of optical microscopes. In general, Gold wires were manufactured by a drawing process in which a lump of gold was beaten or pulled out of a hole or by a process of twisting a gold plate. However, Gold wires separated from the handle of the Phoenix-shaped Glass Ewer did not involve any trace of twisting on the surface. Rather, fine vertical stripes were observed with the sections filled up. Hence, it is thought that this Ewer went through a drawing process and then was mended. As a result, no certain relation with the golden mending material used for the Phoenix-shaped Glass Ewer was verified. The findings above indicate that most of the existing researches on Gold wires recognized them, not as separate remains, but merely as a component of other golden remains. Thus, there has been little systematic study on the manufacturing techniques of Gold wires. The future study on Gold wires may verify the correlation between the Gold wires used to fix the handle of the Phoenix-shaped Glass Ewer, which is examined in this study, with that of golden remains in the Silla era.

Effect of Starvation on Some Parameters in Rhynchocypris oxycephalus (Sauvage and Dabry): A Review (버들치, Rhynchocypris oxycephalus (Sauvage and Dabry) 기아시 일부형질에서의 효과: 개관)

  • Park In-Seok
    • Korean Journal of Environmental Biology
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    • v.22 no.3
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    • pp.351-368
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    • 2004
  • Following the previous experiments, a starvation experiment was conducted to determine the influence of feeding and starvation on the histological and biochemical changes, the morphormetric changes in the sectioned body and the morphometric changes in Rhynchocypris oxycephalus (Sauvage and Dabry). The influence of starvation on nutritional conditions of the histological changes of hepatocyte and intestinal epithelium as hepatosmatic index (HSI), protein, RNA and DNA concentrations of liver in R. oxycephalus was tested. Although the starved group showed higher concentrations of protein, DNA and RNA than the fed group, food deprivation resulted in a decrease in the HSI, hepatocyte nucleus size and nuclear height of the intestinal epithelium. The RNA - DNA ratio appears to be a useful index of nutritional status in R. oxycephalus and may be useful for determining if R. oxycephalus is in a period of rapid or slow growth at the time of sampling. Additionally, the data have been interpreted in detail and some biologically important relationships discussed. The effects of starvation on the morphometrical changes in sectioned body traits, condition factor, viscera index and dressing percentage were determined for evaluating nutritional conditions of R. oxycephalus. Starvation for nine weeks resulted in a decrease in most sectioned traits as well as in condition factor and viscera index (P<0.05). These findings suggest that nutritional parameters used in this study appear to be a useful index for nutritional status in this species. The data has been interpreted in detail and some important body sectioned values of interest to commercial growers discussed. A 75-day study was conducted to determine the effect of starvation on classical and truss parameters in R. oxycephalus. Truss dimensions of almost the entire head and trunk region as well as the abdomen were increased significantly through feeding or starvation (P<0.05). Truss dimensions of the caudal region generally decreased through feeding or starvation, particularly those dimensions at the hind part of the trunk. There were some significant decreases in classical dimensions of the head region during feeding, in relation to body depth characteristics in the trunk and caudal region during starvation, whereas there was only one decreasing classical dimension in the caudal region during feeding. The results of this study indicate that application of the truss network as a character set enforces classical coverage across the body form, discrimination among experimental groups thus being enhanced. Considering that the dimension of the lower part of the head and some truss and classical dimensions were least affected by feeding and starvation, these dimensions may then be useful as a taxonomical indicator to discriminate the species of Rhynchocypris sp. The value of trunk region dimensions with a large component of body depth in R. oxycephalus is most likely to be compromised by variability related to differences in feeding regimes of fish in different habitats.

영양-울진지역 선캠브리아기 변성암류의 변형작용사

  • 강지훈;김남훈;박계헌;송용선;옥수석
    • Proceedings of the Mineralogical Society of Korea Conference
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    • 2003.05a
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    • pp.84-85
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    • 2003
  • 소백산육괴의 동부에 분포하는 영양-울진지역의 선캠브리아기 변성암류는 평해층, 기성층, 원남층, 평해화강편마암, 하다우백질화강편마암 등으로 구성되어 있다(김옥준 외, 1963). 그러나, 최근 김남훈 외(2001, 2002)은 야외조사연구와 암석학적 및 지구화학적 연구를 통하여 주로 변성화산암류로 기재되었던 기성층은 변성화산암류가 아니라 평해층과 원남층에서 산출되는 화강암질편마암과 각섬암 기원의 변성암류가 연성전단변형을 받아 형성된 압쇄암 내지 초압쇄암으로 되어 있고, 기존의 기성층은 변성화산암류와 같이 성분상으로 구분되는 별개의 층이 아닌 구조적으로 만들어진 연성전단대의 중심부일 가능성을 시사한 바가 있다. 본 연구는 연성전단대의 연장성 및 연성전단대 형성과 관련된 지구조운동의 특성을 파악하고, 중첩된 변형구조들의 선후관계로부터 영양-울진지역 선캠브리아기 변성암류에 대한 변형작용사를 규명하기 위해 기성층의 분포지를 중심으로 이 지역 선캠브리아기 변성암류에 대한 상세한 야외지질조사를 실시하였다. 그 결과, 예천(북후면-평은면)지역을 통과하여 봉화 부근에서 동북동-서남서 방향이 동-서 방향으로 전환하여 장군봉지역까지 연장되는 것으로 알려져 있는 우수 주향 이동성 예천전단대(KIGAM, 1995; 강지훈 외 1997; 강지훈, 2000; 강지훈과 김형식, 2000)는 영양-울진지역까지 연장됨이 확인된다. 또한, 영양-울진지역의 선캠브리아기 변성암류에는 연성전단변형 이전에 적어도 한 번의 습곡작용과 이후에 적어도 두 번의 습곡작용이 인지된다. 각 변형단계별 특징적인 구조요소를 요약하면 다음과 같다. D1 변형: 편마면 내지 편리(S0)가 습곡되어 형성된 F1 습곡은 동-서 방향의 준 수평적인 습곡축을 갖는 뿌리 없는 등사습곡 형태로 인지된다. 양 날개부의 S0 엽리는 F1 습곡축면(S1)으로 완전히 전위된 하나의 엽리(S0-1)로 나타나고, S0-1 엽리는 이 지역의 광역엽리로 인지된다. S0-1 광역엽리는 구성암류의 대상 분포 방향과 유사한 서북서 주향에 북쪽으로 중각 경사하는 집중된 방향성을 보이며 분산되어 나타난다. D2 변형: 변형구조로는 신장선구조, 압쇄구조면, 비대칭습곡 등으로 인지된다. 신장선구조는 S0-1 엽리면상에서 주로 신장된 석영(집합체)과 장석(집합체)들의 정향배열에 의해 정의되고, S0-1 엽리의 주향 방향으로 저각으로 침강하는 집중된 방향성을 보이며 분산되어 나타난다. 신장선구조에 평행하고 S0-1 엽리에 수직한 단면에서는 상부-동쪽-이동의 우수주향 이동성 연성 전단운동감각을 지시하는 구조요소들이 다량 관찰된다. 연성전단변형에 의해 형성된 압쇄구조면은 전단엽리와 압쇄엽리에 각각 해당하는 C면과 S면 등이 인지된다. 전단엽리 C면은 S0-1 광역엽리와 거의 일치하고, 압쇄엽리 S면은 F2 비대칭습곡의 축면엽리와 거의 일치한다. S0-1 엽리를 습곡시키는 F2 비대칭습곡은 S0-1 엽리를 전단면으로 하여 상부-동쪽-이동 전단운동에 의해 형성된 밀착습곡 형태로 인지된다. F2 습곡축은 북동 방향으로 중각 내지 저각 침강하고 F1 습곡축과는 65$^{\circ}$-75$^{\circ}$ 범위의 사이각을 이룬다. F2 습곡축면은 동북동 주향에 북쪽으로 중각으로 경사하고 F1 습곡축면과는 20$^{\circ}$-40$^{\circ}$ 범위의 사이각을 이룬다. D3 변형. S0-1 엽리와 압쇄구조면 등을 습곡시키는 F3 습곡은 준 수평적인 습곡축과 습곡축면을 갖는 개방 횡와습곡의 형태로 인지된다. D4 변형: F4 습곡은 비대칭 공역성 킹크습곡, 공역성 충상단층에 수반되어 나타나는 드래그습곡, 대칭 개방 직림습곡 등의 다양한 습곡 형태로 인지된다. 이들 F4 습곡의 축면엽리는 일반적으로 동-서 주향에 남쪽과 북쪽으로 경사한다. 그 경사각은 비대칭 공역성 킹크습곡(저각), 드래그습곡(중각), 대칭 개방 직립습곡(고각) 순으로 고각을 이룬다. F4 습곡축은 동쪽과 서쪽으로 저각 침강하는 집중된 방향성을 보인다. 공역성 충상단층은 동-서 주향에 남쪽과 북쪽으로 경사하는 단층면과 상부가 북쪽과 남쪽으로 충상하는 운동상을 보인다. 드래그습곡의 축면엽리는 이러한 공역성 충상단층운동의 전단압축방향에 수직으로 발달한다. 이러한 D4 변형구조는 남-북 방향의 압축 지구조 환경하에서 형성된 것으로 고찰된다.

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Time-Lapse Crosswell Seismic Study to Evaluate the Underground Cavity Filling (지하공동 충전효과 평가를 위한 시차 공대공 탄성파 토모그래피 연구)

  • Lee, Doo-Sung
    • Geophysics and Geophysical Exploration
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    • v.1 no.1
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    • pp.25-30
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    • 1998
  • Time-lapse crosswell seismic data, recorded before and after the cavity filling, showed that the filling increased the velocity at a known cavity zone in an old mine site in Inchon area. The seismic response depicted on the tomogram and in conjunction with the geologic data from drillings imply that the size of the cavity may be either small or filled by debris. In this study, I attempted to evaluate the filling effect by analyzing velocity measured from the time-lapse tomograms. The data acquired by a downhole airgun and 24-channel hydrophone system revealed that there exists measurable amounts of source statics. I presented a methodology to estimate the source statics. The procedure for this method is: 1) examine the source firing-time for each source, and remove the effect of irregular firing time, and 2) estimate the residual statics caused by inaccurate source positioning. This proposed multi-step inversion may reduce high frequency numerical noise and enhance the resolution at the zone of interest. The multi-step inversion with different starting models successfully shows the subtle velocity changes at the small cavity zone. The inversion procedure is: 1) conduct an inversion using regular sized cells, and generate an image of gross velocity structure by applying a 2-D median filter on the resulting tomogram, and 2) construct the starting velocity model by modifying the final velocity model from the first phase. The model was modified so that the zone of interest consists of small-sized grids. The final velocity model developed from the baseline survey was as a starting velocity model on the monitor inversion. Since we expected a velocity change only in the cavity zone, in the monitor inversion, we can significantly reduce the number of model parameters by fixing the model out-side the cavity zone equal to the baseline model.

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Development of remote control automatic fire extinguishing system for fire suppression in double-deck tunnel (복층터널 화재대응을 위한 원격 자동소화 시스템 개발 연구)

  • Park, Jinouk;Yoo, Yongho;Kim, Yangkyun;Park, Byoungjik;Kim, Whiseong;Park, Sangheon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.1
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    • pp.167-175
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    • 2019
  • To effectively deal with the fire in tunnel which is mostly the vehicle fire, it's more important to suppress the fire at early stage. In urban tunnel, however, accessibility to the scene of fire by the fire fighter is very limited due to severe traffic congestion which causes the difficulty with firefighting activity in timely manner and such a problem would be further worsened in underground road (double-deck tunnel) which has been increasingly extended and deepened. In preparation for the disaster in Korea, the range of life safety facilities for installation is defined based on category of the extension and fire protection referring to risk hazard index which is determined depending on tunnel length and conditions, and particularly to directly deal with the tunnel fire, fire extinguisher, indoor hydrant and sprinkler are designated as the mandatory facilities depending on category. But such fire extinguishing installations are found inappropriate functionally and technically and thus the measure to improve the system needs to be taken. Particularly in a double-deck tunnel which accommodates the traffic in both directions within a single tunnel of which section is divided by intermediate slab, the facility or the system which functions more rapidly and effectively is more than important. This study, thus, is intended to supplement the problems with existing tunnel life safety system (fire extinguishing) and develop the remote-controlled automatic fire extinguishing system which is optimized for a double-deck tunnel. Consequently, the system considering low floor height and extended length as well as indoor hydrant for a wide range of use have been developed together with the performance verification and the process for commercialization before applying to the tunnel is underway now.

Numerical modeling of secondary flow behavior in a meandering channel with submerged vanes (잠긴수제가 설치된 만곡수로에서의 이차류 거동 수치모의)

  • Lee, Jung Seop;Park, Sang Deog;Choi, Cheol Hee;Paik, Joongcheol
    • Journal of Korea Water Resources Association
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    • v.52 no.10
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    • pp.743-752
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    • 2019
  • The flow in the meandering channel is characterized by the spiral motion of secondary currents that typically cause the erosion along the outer bank. Hydraulic structures, such as spur dike and groyne, are commonly installed on the channel bottom near the outer bank to mitigate the strength of secondary currents. This study is to investigate the effects of submerged vanes installed in a $90^{\circ}$ meandering channel on the development of secondary currents through three-dimensional numerical modeling using the hybrid RANS/LES method for turbulence and the volume of fluid method, based on OpenFOAM open source toolbox, for capturing the free surface at the Froude number of 0.43. We employ the second-order-accurate finite volume methods in the space and time for the numerical modeling and compare numerical results with experimental measurements for evaluating the numerical predictions. Numerical results show that the present simulations well reproduce the experimental measurements, in terms of the time-averaged streamwise velocity and secondary velocity vector fields in the bend with submerged vanes. The computed flow fields reveal that the streamwise velocity near the bed along the outer bank at the end section of bend dramatically decrease by one third of mean velocity after the installation of vanes, which support that submerged vanes mitigate the strength of primary secondary flow and are helpful for the channel stability along the outer bank. The flow between the top of vanes and the free surface accelerates and the maximum velocity of free surface flow near the flow impingement along the outer bank increases about 20% due to the installation of submerged vanes. Numerical solutions show the formations of the horseshoe vortices at the front of vanes and the lee wakes behind the vanes, which are responsible for strong local scour around vanes. Additional study on the shapes and arrangement of vanes is required for mitigate the local scour.