• Tunnel and Underground Space
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• v.17 no.4
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• pp.266-284
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• 2007

Recently, many efforts have been made to construct the first unlined tunnel, without in-situ concrete lining, in Korea. However, the lack of reliability in the performance of shotcrete as permanent tunnel support prevented from its realization. Shotcrete has been regarded to have significant problems in field application and long term performance because of unsatisfactory strength level and durability compared to those of European countries. In this study, the high strength shotcrete satisfying compressive strength over 40 MPa and flexural strength over 4.5 MPa was developed from optimized mix design. The type of accelerators and the amount of silica fume were selected as the main factors in mixing process and the analyses were carried out up to the elapsed time of 2 years. In order to evaluate the short term durability of shotcrete, an array of laboratory test consisting of freeze-thaw, carbonation chloride penetration and permeability test was performed. For long-term durability tests, specimens have been put in an operated highway tunnel to expose them to the similar environment when they are actually used as an unlined tunnel support. From the strength and durability tests, it was found that only alkali-free based accelerator satisfied the target strength of this study and also, the developed shotcrete showed very high performance in its durability.

• Proceedings of the KOR-KST Conference
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• 1999.10a
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• pp.15-20
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• 1999

아시아지역은 경제적 침체기에서 서서히 회복되어가면서 항공교통수요 또한 경제적 위기 이전의 수준으로 회복해가고 있고 21세기의 새로운 출발과 동북아지역 국가들의 경제활동 활성화로 새로운 항공교통수요가 증대되어가고 있는 시점이다. 동북아 국가들은 자국의 경제 활성화를 위해 공항의 새로운 건설과 확장 등을 계획$.$실행해오고 있으며, 이를 통하여 동북아지역에서의 항공산업의 우위성을 확보하려하고 있다. 중국, 일본 등 우리나라와 경쟁관계에 있는 나라들이 기존 공항의 확장과 신설을 통해 경쟁력을 높이려하고 있으며, 공항의 경쟁력을 높이는데 필수적 요소 중의 하나인 외국 항공사의 유치를 위한 對항공사 마케팅을 다양하고 구체적인 방법으로 실행하고 있다. 우리나라도 2001년 동북아의 중추적인 공항의 건설과 개항을 맞이하여 이들 경쟁공항과의 경쟁에서 우위성을 확보하기 위한 하나의 방안으로서 자국 및 외국항공사의 비행편 유치에 대한 공항마케팅 측면에서의 접근이 필요하게 되었다. 본 연구는 우리나라와 지리적인 국토면적 여건이 비슷한 암스테르담 스키폴공항, 히드로공항 등의 공항들이 취하고 있는 대항공사마케팅 정책과 대항공사 유치를 위해 현재 실행하고 있는 방법들을 통해 앞으로 인천국제공항이 공항마케팅에서의 대항공사 마케팅 전략 수립시 고려 방안들을 제시하고자한다. 이에 공항마케팅의 일반적인 고찰과 외국 선진공항들의 대항공사마케팅전략을 고찰하고, 현재 인천국제공항의 경쟁공항인 동북아지역의 중국 및 일본 공항들의 현황등을 살펴보고자 한다. 마지막으로는 계량적 방법과 문헌들을 통해 여러 가지 방안들을 고려하여 인천국제공항이 실행하여야하는 대항공사마케팅전략방안을 제시하여 본 연구의 목적을 달성하려한다. 및 화물교통량의 증가를 예상하여 5%, 10%, 20%의 증가에 대한 민감도 분석을 실시한 결과 대안1의 경우 교통량의 변화 및 화물통행의 시간가치의 증가시 사회적 편익이 오히려 감소하였고, 대안2와 3의 경우 사회적 편익이 증가하는 것을 알 수 있었다. 이는 경부고속도로의 화물차량의 구성비에 따라 대안 1의 경우 오히려 화물차의 통행시간이 증가함에 그 원인이 있다 할 것이다. 이상과 같은 결론을 통하여 경부고속도로상의 화물전용차선의 설치시는 수답렬 교통량의 구성비와 구간 평균교통량에 의하여 그 효과가 다르게 나타남을 알 수 있었다. 따라서 물류비용 절감차원에서의 화물전용차선의 설치는 본 연구에서 나타낸 방법과 같이 수단간의 경제적 편익을 고려한 구간별 시간대별 효과분석을 통하여 정책의 시행여부가 결정되어야 할 것이다. 한편, 화물전용차선의 설치로 인한 물류비용의 절감을 보다 효과적으로 달성하기 위해서는 종합류류 전산망의 시급한 구축과 함께 화물차의 적재율을 높이고 공차율을 낮출 수 있는 운송체계의 수립이 필요한 것으로 판단된다. 그라나 이러한 화물전용차선의 효과는 단기적인 치유책일 수밖에 없기 때문에 물류유통 시설의 확충을 위한 사회간접자본의 구축을 서둘러 시행하여야 할 것이다.으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압주입시험에서도 확인된다.. It was resulted

• Tribology and Lubricants
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• v.12 no.1
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• pp.1-5
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• 1996

자성유체는 자연에서 추출한 것이 아니라 자화성(Magnetizability)과 유도성(Flowability)을 동시에 갖도록 합성한 특수액체이다. 자성유체는 1960년대 중반에 미국의 NASA에서 처음 개발된 이후로 윤활, 밀봉, 감쇄, 의료 등의 분야에서 응용연구가 많이 진행되었기 때문에 고도의 정밀도를 요하는 항공, 우주산업, 컴퓨터와 반도체 분야 등에서 실용화가 크게 진전되고 있다. 특수물질일 자성유체는 전기적으로 도체인 10nm 정도의 미세한 자기입자(Magnetic particles)에 코팅을 한 후, 이것을 물, 탄화수소, 플루오르카본, 에스터 등의 매개유체(Carrier Fluids)에 혼합시켜서 콜로이드 상태로 사용하게 된다. 자성유체는 미세한 자기입자들이 매개유체내에서 서로 충돌하면서 반발력을 발생시켜서 상호간에 늘 콜로이드 상태를 유지하고 있으며, 이 특수유체가 자기장의 영향을 받게 되면 점도가 증가하면서 특이한 성질을 갖게 된다. 상대 접촉 운동면에 경계마찰이나 혼합마찰을 하게 되면 윤활상태는 비교적 나쁘다. 이러한 마찰지역에 콜로이드상의 자성유체 윤활제를 공급하면 기존의 윤활제에 비하여 대단히 효과적으로 윤활을 할 수 있게 된다. 그러나 자성유체 윤활제가 마찰부위에 원활하게 공급하기 위해서는 미끄럼 마찰부에서 자기장을 잘 형성시킬 수 있는 도체이어야 하기 때문에 특별한 윤활 시스템 설계가 제시되어야 한다. 자성유체 윤활제는 합성으로 제조된 특수물질로 여러가지 장점을 갖고는 있으나 기존 윤활유와의 적합성, 마찰열, 밀봉압력 등의 조건에서 제한적으로 사용될 수 밖에 없으므로 항공, 우주 산업이나 석유 화학분야와 같이 특수 환경에서만 사용되고, 또한 기존의 광유계 윤활제에 비하여 대단히 고가하는 문제점을 갖고 있다. 그러나 윤활 마찰면의 다양화와 가혹한 사용조건은 자성유체 윤활제의 연구개발 필요성을 크게 증대시키고 있다.xed Effects Model)을 결정하고, 각각에 해당하는 통계모형을 구축하였다. 이 결과 (1) 업종 및 기업규모별로 그룹간에 유의한 특성이 발견되었으며, (2) R&D 및 광고투자는 기업의 시장성과를 설명하는 중요한 변수이나, (3) R&D 투자의 경우는 광고에 비해 불확실성이 존재하는 것으로 나타났고, (4) 수리모형에서 도출된 한계원리가 통계모형에서도 유효한 것으로 드러났다.등을 토대로 한 10대 산업을 육성하기 위하여 과학기술부는 기술수요조사를 바탕으로 49개 주요기술을 도출하여, 과학기술 일류 국가 실현, 국민소득 2만불 달성이라는 국가적 슬로건을 내걸고 “차세대 성장동력” 창출을 위한 범정부차원의 기획과 연구비의 집중투자를 추진하고 있다.달성하기 위해서는 종합류류 전산망의 시급한 구축과 함께 화물차의 적재율을 높이고 공차율을 낮출 수 있는 운송체계의 수립이 필요한 것으로 판단된다. 그라나 이러한 화물전용차선의 효과는 단기적인 치유책일 수밖에 없기 때문에 물류유통 시설의 확충을 위한 사회간접자본의 구축을 서둘러 시행하여야 할 것이다.으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압주입시험에서도 확인된다.. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase in index, as compared to that of control. In case

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.535-543
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• 2017

For column-beam gussets of wooden structures, slit-processed members inserted with a steel plate are used in general. In this study, a rigid portal frame bonded with a joint was fabricated and a semi-rigid portal frame was fabricated by making a wooden gusset, a replacement for steel plate, of which a half was integrated into the column member and the other half was joined with the beam member by drift-pins. The lateral strength performance of the wooden portal frame was compared with that of the steel plate-inserted joint portal frame. The lateral strength performance was evaluated through a perfect elasto-plasticity model analysis, sectional stiffness change rate, and short-term permissible shear strength. As a result of the experiment, the maximum strength of the rigid portal frame was lower than that of the steel plate-inserted joint portal frame. The yield strength and ultimate strength were calculated as 0.58 and 0.48, respectively, but the measurements of initial stiffness and cumulative ductility improved by 1.35 and 1.1, respectively. As a result of the perfect elasto-plasticity model analysis of the semi-rigid portal frame, the maximum strength was lower than that of the rigid portal frame, but the toughness after failure was excellent. Thus, the ultimate strength was higher by 1.05~1.07. The steel plate-inserted portal frame showed rapid decrease in stiffness with the progress of repeated tests, but the stiffness of the portal frames with a wooden joint decreased slowly.

• The Korean Journal of Pesticide Science
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• v.4 no.2
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• pp.1-10
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• 2000

Fungicide resistance study in Korea is still in its infancy, and most of those resistance studies are largely limited to newness of the detected resistant strains. In future, detection of fungicide-resistant strains has to be based on sensitivity distribution of pathogen populations to certain fungicides, and standard levels of certain fungicides for resistance should be determined under the basis of this data. Most of the early research on fungicide resistance in Korea has overlooked this point, and resulted in inconsistency and confusion for monitoring sensitivity shift of pathogen population among individual researchers. Fungicide resistance detected in vitro tests has to be documented in field trials by examining control efficacy against resistant and wild-type pathogen populations. Resistance detection in wife has to be correlated with lower activity in practice. Using this process, fungicide resistance will have a practical meaning. Fitness evaluation of resistant strains for survival is, in particular, of importance to determine the future stability of the resistance in the pathogen population. In fields, sensitivity change of pathogen populations should be carefully monitored with and without fungicide selection pressures to establish long-term management strategies against fungicide resistance. It is becoming an urgent task to provide information through research for designing and implementing successful counter-measures against fungicide resistance problems in Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.2
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• pp.174-190
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• 1996

Damage assessment based on in situ surveys for oil spills in marine environment is limited by fundamental difficulties as well as tremendous expenses. Except for intertidal zones, the damage is not preserved well. Also such surveys are usually confined to adult organisms. To overcome these limitations a computer model, NRDAM/CME, was developed in the case of USA (Reed et al., 1989), where an acute toxicity data base was used to assess indirect damages through food webs and loss due to recruitment as well as adult losses. In the present study damage assessment of natural biological resources for hypothetical oil spills is attempted using a computer model for hypothetical spills of Bunker C and heavy crude oil. In the model, the logical structure of NRDAM/CME was adopted, and biomass and productivity database were compiled for the Korean waters. The results showed that the damage increased in a nonlinear fashion as the spill amount increased. The magnitude of the damage depended upon the chemical properties of oil viscosity and solubility in particular, which implies that usage of oil dispersant might increase the damage by dispersing oil. The results also indicate that long term damage due to recruitment loss could be greater than short term damage.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.3
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• pp.13-21
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• 2007

Recently, very short-term rainfall forecast using radar is required for regional flash flood according to climate change. This research is to evaluate the feasibility of GIS based distributed model using radar rainfall which can express temporal and spatial distribution in actual dam watershed during flood runoff period. Vflo model which was developed Oklahoma university was used as physical based distributed model, and Namgang dam watershed ($2,293km^2$) was applied as study site. Distributed rainfall according to grid resolution was generated by using K-RainVieux, preprocess program of radar rainfall, from JIN radar. Also, GIS hydrological parameters were extracted from basic GIS data such as DEM, land cover and soil map, and used as input data of distributed model(Vflo). Results of this research can provide a base for building of real-time short-term rainfall runoff forecast system according to flash flood in near future.

• Journal of Korean Society of Forest Science
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• v.107 no.1
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• pp.16-24
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• 2018

This study was investigated to select superior population and clones of Salix gracilistyla for promoting woody biomass resources through creating of short rotation coppices (SRC). Plant materials were collected from seven different population groups of S. gracilistyla and planted at two different nursery sites in Chuncheon and Yongin. Height and root collar diameter showed statistically significant differeces among population, nursery, and annual growth for three years (p<0.01). Aboveground biomass was harvested to investigate dry weight after 3 years from planting, the Youngwol population showed the highest yield as $4.8kg\;DW\;plant^{-1}$ in Chuncheon nursery which was more than double yield compared to the other nursery planted plants. However, Hongcheon and Wonju populations as $3.3kg\;plant^{-1}$, showed the best yield in Yongin nursery. In addition, there was a significant difference between collected populations and nurseries. But there was statistically significant different interaction between population (Pop) and nursery (Nur) (F value = 3.51, p<0.01). Therefore, the superior populations selected by this experiment could be cultivated as an excellent variety for woody biomass resources through the clonal test.

• The Journal of Internal Korean Medicine
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• v.28 no.1
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• pp.106-114
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• 2007

Background : Mahuang (Ephedrae Herba, Ephedra sinica $S_{TAPE}$) has been widely used to treat respiratory disease in Asian over the past thousand years. The main ingredient of Mahuang is ephedrine, whose affects on the autonomic nervous system induce some adverse effects like vasoconstriction, hypertension, tachycardia, miosis, insomnia, dizziness, headache, etc. Although there were lots of reports about adverse effects of Mahuang, there were no clinical studies which evaluated the adverse effects of Mahuang on the autonomic nervous system by objective numerical value in the past decade. Objectives : The purpose of this report was to provide an objective assessment of state-trait anxiety that is caused by Mahuang, and to identify anxiety of Mahuang according to different Sasang constitution classifications. Methods : The study design was a double-blind randomized placebo-controlled trial. The subjects of this study were 79 adults aged between 20 to 40 who agreed to participate. Because 8 adults dropped out, a total of 71 subjects entered the study. They were allocated through randomization to a Mahuang group (N=50) and placebo group (N=21). Each group took three opaque capsules (every opaque capsule containing 2g of Mahuang or none) twice a day. To compare the state and trait anxiety before and after taking Mahuang, we checked the anxiety by using STAI-KYZ. Results : The following results were obtained. Short-term administration of Mahuang significantly increased state-anxiety, but in the placebo group, there were no significant changes in state-anxiety. In the Mahuang group except females, there was more significant increase in state-anxiety of Soeumin than Soyangin and Taeumin in the 2nd measurement. Conclusion : It is suggested that the ingestion of Mahuang can increase sympathetic activity and induce anxiety. There was a significant difference among Sasang constitution classification. Especially, the response is stronger in Soeumin than other constitutions. If we use Mahuang according to the Sasang constitution classification in clinic, we could not only minimize the anxiety but maximize the potential curative value.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04b
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• pp.33-40
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• 2002

We, Tong Yang Moolsan Co. Ltd. (TYM) set up the mass-production system for virus-free seed garlic via tissue culture technique. TYM's tissue culture technique is called as 'Multiple shoot propagation technique'. This technique can lead mass propagation of genetically homogeneous seed garlic in a short period because of its highly proliferation ,ate of in vitro shoots $(15^{10}/year)$. TYM researchers applied the technique to some selected garlic cultivars with superior characteristics and carried out Held test of productivity in the inside and outside of the country for several years. According to the yearly results of Held test with virus-free seed garlic, we ascertained that virus-free seed garlic can produce the highly yield increase (max. above 50%) and also can enhance the product quality. Consequently, we estimated that TYM's seed garlic will contribute to farmers with increase of income and can elevate the national position of garlic market in the world for its competitive power of technical and production cost.