• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.33-36
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• 2011

Recently, It has increased to use ultra high strength concrete. It is effective to mix organic fibers for preventing spalling. But if fiber mixed, flowability of concrete is decreases. The aim of this study is to evaluation of fire resistance performance for fiber-mixed ultra high strength concrete on field application. As a result, flowability of nylon fiber mixed concrete is better than polyethylene fiber mixed. In non-fiber and polyethylene fiber mixed concrete, spalling occurred. And strain converged at 0.004. Also, residual strength could not evaluate. Nylon fiber mixed concrete is effective to prevent spalling. And it remians 50% residual strength compare with compressive strength at room temperature.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1042-1045
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• 2004

ITO thin films ($\sim150nm$) are deposited on glass substrates by different deposition condition. The sheet resistance of ITO thin films measured by using a four probe station. The microstructure of these films is determined using a X-ray diffractometer (XRD) and a scanning electron microscope (SEM) and a atomic force microscope (AEM). The sheet resistance of ITO thin films compared $s_11$ values by using a near field scanning microwave microscope.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.419-433
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• 2009

Pressure grouting is a common technique in geotechnical engineering to increase the stiffness and strength of the ground mass and to fill boreholes or void space in a tunnel lining and so on. Recently, the pressure grouting has been applied to a soil-nailing system which is widely used to improve slope stability. The soil-nailing design has been empirically performed in most geotechnical applications because the interaction between pressurized grouting paste and the adjacent ground mass is complicated and difficult to analyze. The purpose of this study is to analyze the increase of pullout resistance induced by pressurized grouting with the aid of performing laboratory model tests and field tests. In this paper, two main causes of pullout resistance increases induced by pressurized grouting were verified: the increase of residual stress; and the increase of coefficient of pullout friction. From the laboratory tests, it was found that residual stress in borehole increases by pressurized grouting and dilatancy angle could be estimated by cavity expansion theory using the measured wall displacements. From the field test results, the pullout resistance of soil-nailing with pressurized grouting was found to be 10% larger than that of soil-nailing with gravitational grouting, mainly caused by mean normal stress increase and dilatancy effect. So, the pullout resistance could be estimated by considering these two effects. The radial displacement increases with dilatancy angle increase and the dilatancy angle decreases with injection pressure increase. The measured pullout resistance obtained from field tests is in good agreement with the estimated one from the cavity expansion theory.

• 한국구조물진단유지관리공학회 논문집
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• 제13권6호통권58호
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• pp.88-96
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• 2009

본 연구에서는 RC구조물의 내구 및 내화성능을 동시에 향상시킬 수 있는 고인성 모르타르 (FR-ECC) 를 개발하여, 이를 RC구조물의 보수재료로서 사용하기 위한 실험적 연구를 실시하였다. 즉, FR-ECC를 이용하여 제조한 콘크리트 시험체의 강도, 열적특성, 모의부재의 철근부식특성, 내화성능 등에 대하여 검토하였으며, FR-ECC의 현장적용 가능성에 대해서도 평가하였다. 그 결과, FR-ECC는 기존 보수 모르타르에 비해 우수한 강도 및 내구성능을 보유하고, 휨균열 발생 후에도 외부열화 인자의 침입을 억제하여 철근부식을 방지하는 것으로 나타났다. 또한 FR-ECC를 적용한 부재는 ISO 834 가열조건에서도 우수한 내화성능을 갖는 것으로 나타났으며, 뿜칠성능 등의 현장시공 성능에서도 우수한 특성을 나타냈다.

• 한국작물학회지
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• 제36권4호
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• pp.319-323
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• 1991

벼의 도복에 관련하는 형질들의 포장도복과의 관련정도를 밝혀 벼의 이도복성육종의 기초자료를 제공코져 1900년대에서 1980년대에 재배 또는 육성된 10품종을 재배하여 실험한 결과를 요약하면 다음과 같다. 1 포장도복정도와 관련정도가 높은 형질들은 간장, 단위간하중(W/l), 단위 직경휨모멘트(W1/d), 도복지수(L), 하중비(W1/P), 임계도 복하중지수 (Ws$^2$/l$^4$)등 이었다. 2. 간장은 포장도복과 높은 상관(r=0.7607)을 보이나 간장만으로 품종의 도복정도를 판정하기는 미흡하였다 3. 측정의 난역도와 소모되는 시간을 고찰해 볼 때 도복저항성을 판정하는데 유용할 형질들은 간장, W/l, W1/d, Ws$^2$/l$^4$이었다. 4. 간경, 줄기단면적, 간벽의 두께, 줄기단면의 2차 관성 모멘트는 포장도복과 아무런 상관관계를 보이지 않았다. 5. 좌절강도(S)는 포장도복과 유의한 부의 상관 (r=-0.3986)을 보였다.

• 식물병연구
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• 제11권2호
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• pp.106-114
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• 2005

To breed powdery mildew resistant varieties, 104 accessions of Cucurbita spp. germplasm were evaluated. Powdery mildew resistance and horticultural characteristics of the accessions were investigated in the field conditions. C. martinezii was selected for high resistance to powdery mildew in the field. The growth of powdery mildew pathogen and response of leaf surface tissue to the pathogen were observed after artificial inoculation to resistant C martinezii and susceptible C. moschata cv. 'Wonye No.402'. Mycelium growth was very clearly different between resistant C. martinezii and susceptible C moschata cv. 'Wonye No. 402' at 5 days after inoculation at the adult stage. Interspecific hybridization was attempted to transfer powdery mildew resistance gene(s) from C. martinezii to C. moschata. A single dominant gene action was postulated as deter mining powdery mildew resistance at the seedling stage. But for the effective selection of powdery mildew resistant individuals, it was established that adult plant resistance should be confirmed in the field conditions after the seedling test. Through the seedling and field tests, C. moschata lines resistant to powdery mildew and superior to horticultural characteristics, were selected after 2 backcrossing and 3 selfing generations. The fruit characteristics of newly developed lines were similar to those of the recurrent parent, 'Jaechenjarae'.

• ETRI Journal
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• 제34권1호
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• pp.134-137
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• 2012

Power metal-oxide semiconductor field-effect transistor (MOSFET) devices are widely used in power electronics applications, such as brushless direct current motors and power modules. For a conventional power MOSFET device such as trench double-diffused MOSFET (TDMOS), there is a tradeoff relationship between specific on-state resistance and breakdown voltage. To overcome the tradeoff relationship, a super-junction (SJ) trench MOSFET (TMOSFET) structure is studied and designed in this letter. The processing conditions are proposed, and studies on the unit cell are performed for optimal design. The structure modeling and the characteristic analyses for doping density, potential distribution, electric field, width, and depth of trench in an SJ TMOSFET are performed and simulated by using of the SILVACO TCAD 2D device simulator, Atlas. As a result, the specific on-state resistance of 1.2 $m{\Omega}-cm^2$ at the class of 100 V and 100 A is successfully optimized in the SJ TMOSFET, which has the better performance than TDMOS in design parameters.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.187-191
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• 2008

It is necessary to develop a technology for effectively controling explosive spalling of high strength concrete caused increasing construction of high rise building and putting up the fireproof standard of high strength concrete by MLTM (Ministry of Land, Transport and Maritime Affairs). Accordingly, it was investigated basic properties such as slump, air content and compressive strength, and fire resistance properties of high strength concrete using polypropylene fiber for field application as a countermeasure for explosive spalling of concrete on fire in this study, As a test result, it was confirmed that PP fiber is available as fire resistance method of high strength concrete.

• Transactions on Electrical and Electronic Materials
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• 제1권1호
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• pp.45-52
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• 2000

The conduction characteristics in Oriented polypropylene (OPP) film were studied over electric field intensities between 10 M/V m and 300 M/V m . The range of the conduction characteristics was divided in to five regions with increasing field intensity. Particularly, in the region from 70 Mb/m to 82 MV/m voltage-controlled negative resistance was displayed. In the negative resistance region current oscillations were also observed the negative resistance characteristics could by explaine by Gibbons theory.

• 한국해양공학회지
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• 제16권2호
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• pp.44-52
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• 2002

The mechanism of pullout resistance of compression anchor is analysed. This anchor is developed through the field pullout tests and the laboratory element test. The compression anchor is characterized by decrease of progressive failure, simple site work, economy and durability compared with tension anchor. The characteristics of compression anchor, compared with tension anchor. mainly are summarized as follows ; (1) The plastic displacement of anchor body is very small during pullout of anchor. (2) Total anchor length decreases by the shortening of free length; (3) The progressive failure is decreased.; (4) The safety factor for pullout resistance increases with time after construction of anchor.