• 한국농공학회지
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• 제37권1호
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• pp.49-54
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• 1995

Three types of floating-type automatic inlet were developed for the purpose of reduc- ing farmer's working hours required for water management and saving irrigation water. The point of automation is to use a float within the inlet which is floated and sinked by the ponding depth of paddy field, Thus opens and closes the control gate of irrigation. Suitability of each inlet may depend on production cost, applicability to paddy field condi- tions, and feasibility to farmers, etc. The first model was composed of three parts : chamber for irrigation control gate, chamber for float controlled by ponding depth, and connection bar between the two parts. It was designed to open and close the control gate gradually as the ponding depth drops and rises to a certain level. The second model was designed to improve the weak point of the first model which is the imperfect-closing of gate when it approaches to the end of ir- rigation. A switch-spring was equipped above the connection bar for perfect opening and closing of gate when the ponding depth reaches to a certain level. The third model was designed by combining the two chambers, that is, cut in halves the inlet volume of the above two models. Magnets were equipped above the float for perfect opening and closing gate. The functional experiment for three developed inlets was successfully carried out and the rating curves were derived.

• 한국농공학회지
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• 제42권4호
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• pp.106-114
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• 2000

An investigation was conducted to get the basic data for establishing maintenance strategy of pipe framed greenhouses. The contents of the investigation consisted of actual state of structures, maintenance status, meteorological disaster, and corrosion characteristics of pipe framework in greenhouses. the number of greenhouses investigated was 108 in total. Most multi-span greenhouses had narrower width and lower height than the standared 1-2W greenhouse, and most of single-span greenhouses were tunnel type. In multi-span greenhouses, the size and interval of frameworks such as rafter, purline, column , and cross beam were mostly suitable, but frameworks of single-span greenhouses were mostly insufficient. After about 7 years in grounds, 8 years in joints, 10 years in bending parts. and 13 years in columns. pipe surface was mostly rusted. Most weak parts in corrosion were pipes in contact with the ground, joints, roll-up shaft pipes, and pipes close to the gutter. Almost all of the greenhouse farmers didn't pay any attention to maintenance affair in a regular interval for pipe framed grenhouses. Many greenhouses have experienced the meteorologicla diaster such as uplift of foundation, partial or complete failure by the hyphoon and/or high winds.

• 한국화재소방학회논문지
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• 제17권4호
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• pp.64-69
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• 2003

주택화재 특히 아파트 저층부나 일반주택은 자동화설비 대신 수동식소화기에 의존하고 있어서 사람이 없거나 노약자만 있을 시에는 화재에 매우 취약하다. 따라서 화채로 인한 희생을 줄이기 위해서는 발생한 화재를 초기에 자동으로 진압하는 것이 가장 중요하며, 이를 위하여 자동감지장치가 탑재된 경제성 있는 자동식소화기가 개발되었다 본 논문에서는 자동식 소화기의 핵심 기능인 열감지부의 최적 성능을 찾기 위하여 감지부 형상과 가열속도에 따른 작동온도와 응답특성 관계를 규명하였다. 자동감지소화기의 감지부의 이융성금속과 캡의 경우 두 재질 모두 열전도성이 우수한 금속임에도 불구하고, 각각의 미소한 두께변화는 주변 대기의 가열속도가 낮을수록 작동온도에 큰 영향을 미치는 것으로 나타났다. 이융성금속 및 캡의 두께를 얇게 할수록 선형적으로 감소하였으며 작동시간을 최고 40초까지 단축할 수 있는 것으로 나타났다.

• The Korean Journal of Ecology
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• 제5권4호
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• pp.176-186
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• 1982

Uptake and effects of treated Cd and Pb in rose moss and tomato were studied in pot cultures. Three horticulural plants on the roadside were tested to determine the contents of heavy metals in plant parts. Yields of rose moss were increased by the increase Pb concentrations in soil. Yields of rose moss by Cd treatment were decreased in 1, 000 ppm group, but increased in 500 ppm group. Portulaca grandiflora Hook. proved to be tolerent of Pb and Cd added in soil. Yields of tomato were decreased by an incrase of Pb concentration in soil, and tomato proved to be weak for Pb added in soil. Pb contents in root, stem, leaf, and flower and seed of rose moss were increased by an in crease of Pb concentration in soil Pb content in root was the highest among them. Pb content was the highest in root of tomato, but the lowest in the stem. Among the heavy metal contents metal contents of three horticultural plants collected by roadside, it was the Chrysanthemum which had the highest contents of heavy metal among them. The heavy metal contents in stem were less than in the other plnat parts in all three plants. The number of flowers in rose moss was decreased by an increase of Pb, and Cd concentration in soil, but in tomato it was increased by an increase of Pb concentration in soil. Amount of rose moss seeds which were collected after cultivation was decreased by Pb, and Cd treatment in soil.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1620-1622
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• 2003

Recently, as the technology for the development of high voltage power apparatus using SF6 gas has made remarkable progress, it became possible to develop more compact power apparatus adopting single body substation system. In these gas insulated power apparatus, it is impossible to achieve perfect and safe insulation using only SF6 gas, because some solid insulation parts should be installed to support current-carrying conductor parts for electrical and mechanical safety. When spacers were installed in SF6 gas insulation system, they were exposed to severe electrical intensification which could reduce system insulation performance and restrict the rated operating voltage So, it is necessary to clarify the dielectric characteristics of spacers by analytically and experimentally, in order to design and develop more compact and optimum gas insulated systems. In this paper, the field distribution of three-phase spacers were investigated using three dimensional electrostatic field analysis tool adopting BEM method. And the obtained results were compared to the conventional two dimensional computations. According to these three dimensional calculations, it was possible to find out weak points in the spacer more clearly and these results could be applied to design more compact and optimum three phase spacer developments.

• 박물관보존과학
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• 제11권
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• pp.43-48
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• 2010

발굴 칠기는 수분 과포화 상태의 수침칠기와 수분이 거의 없는 건조칠기로 나뉠 수 있다. 본 연구는 창원 다호리에서 출토된 건조 상태의 칠기를 대상으로 목질부는 소실되고 칠도막만 남아있는 칠기 유물을 HPC, PSNY-6 를 사용하여 다음과 같은 3 가지 유형으로 처리하였다. 입체적 형태를 유지하면서 강화하는 방법, 칠도막이 취약하여 칠기의 형태가 드러날 정도로 세척한 후에 흙 채 강화처리하는 방법, 칠기편만으로 그 형태를 유지하기 어려운 경우에 레이온지로 결실 부위를 연결·지지해주거나 또는 전체를 보강해 주는 방법으로 처리하였다.

• Geomechanics and Engineering
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• 제18권3호
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• pp.277-289
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• 2019

In this study, an innovative anchoring approach has been developed dealing with all relevant aspects in consideration of previous works. An ultimate pulling force calculation of anchor is presented from a geotechnical point of view. The proposed umbrella anchor focuses not only on the friction resistance capacity, but also on the axial capacity of the composite end structure and the friction capacity occurring around the wedge. Even though the theoretical background is proposed, in-situ application requires high-level mechanical design. Hence, the required parts have been carefully improved and are composed of anchor body, anchor cap, connection brackets, cutter vanes, open-close ring, support elements and grouting system. Besides, stretcher element made of aramid fabric, interior grouting system, guide tube and cable-locking apparatus are the unique parts of this design. The production and placement steps of real sized anchors are explained in detail. Experimental results of 52 pullout tests on the weak dry soils and 12 in-situ tests inside natural soil indicate that the proposed approach is conservative and its peak pullout value is directly limited by a maximum strength of anchored soil layer if other failure possibilities are eliminated. Umbrella anchor is an alternative to conventional anchor applications used in all types of soils. It not only provides time and workmanship benefits, but also a high level of economic gain and safe design.

• 소성∙가공
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• 제31권5호
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• pp.261-266
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• 2022

To reduce the weight of the vehicle, the application of the high strength steel sheets to chassis parts is increased. High forming load is induced during the shearing process of steel chassis parts made of high strength steel, and the possibility of an eccentric load is increased depending on the product seating condition on the die, which decreases the stability and lifespan of the die. In this paper, a three-dimensional finite element analysis with the continuum element was conducted using the damage theory for the cam-trimming process of the front lower arm. The structural analysis of the trimming die was performed with the forming load result obtained from the analysis, and the amount of deflection and the stress distribution of the die during the shearing process were evaluated for the confirmation of the tool stability. The shape of the weak region of the die was modified according to structural analysis and then the stability was confirmed with the finite element analysis. The analysis result showed that the possibility of tool failure during cam-trimming process was remarkably reduced, and the reliability of the proposed modified design was validated.

• 한국산학기술학회논문지
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• 제15권2호
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• pp.609-615
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• 2014

최근 글로벌 경기 침체로 인한 완성차 수요 급감으로 세계 자동차부품산업이 위기에 직면해 있다. 미국 자동차부품업체들은 2008년 4분기 이후 대규모 적자를 기록 중에 있으며, 고성장세를 유지하던 일본 및 유럽 부품업체들도 경영실적이 크게 악화되었다. 국내 자동차부품기업도 이러한 영향에서 벗어나기가 어려울 것으로 예상된다. 본 연구는 자동차부품 중소기업 중 상장된 25개의 업체를 대상으로 DEA분석기법을 활용하여 각 기업에 대한 상대적 효율성을 분석하였다. 효율성분석결과 CCR모델에서는 전체 25개 기업 중 6개 기업이 효율적인 것으로 나타났지만 기업의 규모를 고려한 효율성 분석인 BCC분석결과 12개 기업이 효율적으로 운영하는 것으로 나타났다. 그리고 25개의 자동차부품기업 중 효율성이 1인 기업이 DMU 1, 5, 7, 10, 18, 24로, 다른 자동차부품기업이 상대적으로 벤치마킹을 해야 할 대상은 DMU 1, 10, 24로 나타났다. 본 연구의 결과를 바탕으로 국내 자동차부품기업이 나가야 할 방향을 제시하고, 국내 자동차부품기업의 효율성을 실증적으로 분석하여 경영효율성을 제고함으로써 향후 자동차부품기업을 경영하는데 있어 매우 중요한 정보를 제공할 것으로 기대된다.

• 비교문화연구
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• 제38권
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• pp.433-459
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• 2015

This paper aims at a better understanding of the concept of korean separable syntactic atom, of which inner parts is separable in syntax, and at examining whether or not this concept can apply to derivatives, functional complex constructions, idiomatic expressions in korean. I defined a syntactic atom as a minimum unit which is drawn directly from lexicon and then is applied to syntactic rules. And I insist that so-called 'lexical island constraint' has some problems and that the syntactic rules can be applied to inner parts of syntactic atom, if the syntactic rules is irrelevant to new syntactic atom formation. The greater part of derivatives is non-separable syntactic atoms. But the likes of '반짝거리다', '죄송스럽다', '칭얼대다' are the separable syntactic atoms. The degree of separability of them is different in the insertion of korean particles or negative adverbs and the omission of root of sytactic atom. The derivatives of 'X-적', of which roots is regular nominal roots, permit the syntactic link between roots and the syntactic combination of the root and its argument. These kinds of derivatives is separable syntactic atoms. Also the derivatives of 'bracket paradox' and 'X-답-' derivatives is separable syntactic atoms. All functional complex constructions are not separable syntactic atoms. According to the degree of grammaticalization, inner parts of some are separable, some is non-separable. Separable functional complex constructions only permit the switching of endings or Josas but not application of other syntactic rules. All idiomatic expressions which are composed of two or more syntactic atoms are separable syntactic atoms. Some of them have so strong separability to allow the insertion of syntactic atom, adverb or adnominal modification and the noun in idiomatic expression to become the head of the relative clause. And some idiomatic expressions which have weak separability only permit interrogative's substitution or form change in fraction of idiomatic expressions.