• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.454-463
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• 2000

A method is presented to alter the geometry of the conventional linearly shaped wire antenna for increasing its bandwidth. The synthesis is two-demensionally symmetric and is based on the minimization of frequency-dependence of the boresight far-field electric field intensity. The current distribution on the wire is calculated by Galerkin method using pulse functions. The shaping limitation for wide-band characteristics is still found because of standing waves due to reflected waves from antenna ends. The limitation overcome by a distribution of resistive loads near ends of wire. The antenna loaded resistively has flat characteristics satisfying a power gain of $6.5\pm1.1$dBi and VSWR of at most 2 over 10:1 bandwidth. The results are verified by comparing with similar results for the conventional linear V-dipole.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.341-345
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• 2010

The prevalence and antimicrobial susceptibilities of Staphylococcal isolates from bovine milk samples were assessed. From January 2009 to October 2009, a total 287 bovine milk samples were randomly collected from 15 stock raising farms located in northern area of Kyunggi province and cultured for the presence of Staphylococci spp. A total 79 staphylococcal isolates were recovered from the milk samples. The predominant isolates were S. aureus (43.03%) and S. chromogenes (24.05%). Antimicrobial resistance patterns of 79 Staphylococcal isolates against ampicillin, chloramphenicol, ciprofloxacin, erythromycin, gentamicin, oxacillin, teicoplanin, tetracyclin, and vancomycin were tested. Staphylococcal isolates revealed the highest resistance to ampicillin (56.96%) and oxacillin (39.23%). Of 31 oxacillin resistance strains, 8 strains carry mecA gene which is responsible for methicillin resistance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6504-6510
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• 2015

Horizontally curved I-girders are subjected to not only bending moments but also torsional moments. The torsional moment of the plate girder is addition of St. Venant torsion and non-uniform torsion. In the flange of I-shaped plate girder, a kind of open-section, the normal stresses is not distributed uniformly due to the non-uniform torsion. Because of that, one of compression flange tip can be yielded faster than the flange of general straight girder. In other words, the flange local buckling strength is decreased when the girder has initial curvature. In this paper, the numerical analysis is conducted to investigate the average stresses in flange for curved girders. The subtended angle and slenderness ratio are taken as parameters.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.290-290
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• 2009

유기 배 과수원의 생물종 다양성을 조사한 결과, 월동 직후 유기배 과수원에서는 13종 503마리, 관행 과수원에서 11종 145마리의 토양 미소동물이 채집되었다. 채집된 종류는 거미, 지네, 노래기와 곤충들이다. 유기과수원에는 특히 응애와 거미가 많이 채집되었으며 특히 곤충 중에서 톡토기는 247마리로 관행에 비해 7배가 많이 채집되었다. 또한 생태지수인 종다양도가 관행 1.383에 비해 1.589로 더 높았다. 서식지별 분포를 보면 나무 바로 밑의 개체수와 종수가 더 많아 배나무 뿌리를 중심으로 생활하고 있음을 확인하였다. 여름철 토양동물의 분포는 달팽이, 지렁이를 비롯한 미소 동물들이 유기인증 과수원에는 24종 632마리, 관행에서는 15종 340마리가 채집되어 유기인증 농가에서 월등히 많은 토양동물이 살고 있었으며 종다양도역시 유기농가 2.021로 관행인 1.652보다 높았다. 청목(1985)의 자연도 평가 A그룹종은 환경저항성이 낮아 쉽게 소멸되는 그룹으로 애지네, 노래기 땅지네 등이 여기에 속하는데 유기농가에서 개체수들이 더 많이 채집되었다. 추락트랩을 이용한 조사에서 딱정벌레 중 점박이먼지벌레가 관행 과수원에서 월등히 높았으며 유기농가에서는 큰넓적송장벌레가 채집되어 이들 종이 지표종으로 선발될 수 있을 것으로 보인다. 또한 거미류 중에 수풀오소리거미가 많이 채집되었으며 채찍늑대거미, 꼬마게거미, 점게거미등은 유기농가에서만 채집되어 추후 이들 종이 지표종으로 선발될 가능성이 있었다. 말레이트랩에서는 고치벌과 맵시벌 종류가 많이 채집되었고 파리류에서는 초파리가 많았으며 털검정파리는 유기인증 농가에서 만이 채집되었다. 유아등을 이용한 야간 곤충류를 채집한 결과 유기농가에서 16종 201마리, 관행 9종 42마리가 채집되어 야간에 활동하는 곤충류 역시 유기농가가 많았다. 추락트랩과 말레이트랩모두 유기인증 농가에서 종다양도가 관행보다 높았으며 유아등 채집에서도 마찬가지 결과를 보여 유기배 과수원이 토양 뿐 아니라 배를 중심으로 생활하는 모든 동물들의 종 다양성이 우수함을 알 수 있었다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1471-1476
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• 2011

The catalytic converter in the front part of an automobile's exhaust system converts toxic exhaust gas into nontoxic gas. The substrate in the central part of the converter has a circular or oval-shaped cross section and fine lattice-shaped walls. In the canning process, the substrate is wrapped in mats and inserted into a can. During this process, mat pressure is induced, which may cause brittle fracturing in the substrate. In this paper, a finite element program for determining the mat pressure distribution was developed to avoid these fractures. The program was created in Microsoft EXCEL, so the input and output procedures are relatively simple. It was assumed that the substrate is rigid, the mat is material nonlinear, and the can is linear elastic. The can is modeled as a beam element to resist both bending and uniform tension/compression. The number of elements is fixed to 35, and the number of iterations, to 20. The solutions are compared to ABAQUS solutions and found to be in good agreement.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.5
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• pp.72-77
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• 2006

This paper presents a comparison of experimental value by electrolytic tank experimental apparatus and calculated value by CDEGS program for potential rise of structure. When a test current flowed through structure models, potential rise was measured and analyzed for types of structure using the electrolytic tank experimental apparatus in real time, and was computed by means of CDEGS program. The structure models were designed and fabricated with four types on a scale of one-one hundred sixty. When the experimental data were compared with the theoretical values, the similar profile was shown. Therefore, the confidence of measurement was obtained. Potential rise was the lowest value at electric cage type(structure model B). The distributions of potential rise are dependent on the resistivity and absorption percentage in concrete attached to structure.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.35-44
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• 2006

Various geophysical methods and geological survey were applied for prospecting of geothermal resources and the attitude of volcanic body at northern part of Kumseongsan, Euiseong. They include magnetic, self-potential, radioactive and resistivity methods, temperature logging near the earth's surface and geological survey. The results of this study are summarized as follows. Various geophysical anomalies is related to the geologically Cretaceous conduit. Anomalies of resistivity and temperature logging seem to be related to the geological structure and terrestrial heat. Small radioactive and self-potential anomalies seem to be associated with chemical character of rocks. The sedimentary rocks dip steeply toward the volcanic rocks, aquifuge. Ideal geological structure for bearing ground water and geothermal resources was founded in the study area. The study area and the adjacent two hot springs area consist of Cretaceous sedimentary and volcanic rocks, and have similar geology.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.22-23
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• 2002

Titanium은 높은 강도, 낮은 밀도, 부식에 대한 저항 등, 타 금속에 비해 월등히 뛰어난 성질을 가지고 있기 때문에 산업 전반에 거쳐 그 응용이 크게 증가하고 있으며, 특히 고온에서의 응용이 중요성을 띠게 됨에 따라 고온으로의 상전이 관계에 따른 구조적 규명이 필요하다. 순수한 titanium은 상온에서 조밀충진 육방정계의 α-상구조(a=2.953Å, c=4.683 Å, P6₃/mmc)를 이루고 있으나, 대략 880℃ 이상에서는 β-상의 체심입방정계 (a=3.320Å, Im3m)로 상전이가 되는 것으로 알려져 있다. 이에 대한 대부분의 연구가 kinetics와 thermodynamics에 관련되어 있으며, TEM을 이용한 직접가열실험은 거의 전무한 상태이다. 본 실험에서는 TEM 직접가열을 통하여 titanium의 고온에서의 상전이와 가열시 발생할 수 있는 산화층 형성을 연구하였다. TEM 시편은 순도 99.94％의 titanium foil(Alfa Aesar, ＃00360, 0.025mm thick)를 이용하였고, 분석 장비로는 에너지여과 기능이 있는 TEM(EM912 Omega, Carl Zeiss)과 Gatan사의 double-tilt heating holder를 사용하였다. Titanium의 상전이를 관찰하기 위해 900℃ 까지 분당 10℃ 의 속도로 가열을 하였다. 통계적 분석 오차를 줄이기 위해 서로 다른 4군데의 관찰영역을 선택하여, 상온 - 600℃ - 900℃ - 상온의 단계별로 회절패턴을 관찰 및 기록하였고, 발생 가능한 산화에 대해서는 동일한 장비를 사용하여 EDS 분석을 하였다. 상온에서의 서로 다른 영역의 회절패턴들은 결함의 존재에 상관없이, 온도가 증가함에 따라 그 결함수가 증가하게 된다. 특히 600℃ 에서는 쌍정과 관련된 회절점들이 본래의 회절점 주위에 형성되어있지만, 각 면들의 격자상수의 변화는 나타나지 않았다. 그러나 900℃ 에서는 쌍정에 의한 회절점의 수가 증가하며, 회절점 사이에 발달한 뚜렷한 막대모양의 강도분포와 격자상수의 변화를 관찰할 수 있었다. 다시 상온으로 냉각시킨 후 관찰한 각각의 회절패턴에서는 격자 상수의 감소와 함께 900℃에 보여진 막대 모양의 강도분포와 쌍정에 의한 회절점들이 여전히 남아있었다. EDS분석 결과 가열 실험을 통해 시편이 열적 산화가 되어 있음을 확인 할 수 있었다. 순수한 titanium의 α-상에서 β-상으로의 상전이를 파악할 수 있는 격자상수의 변화자체는 매우 작은 값이기 때문에 상온과 900℃ 에서 기록된 전자회절패턴 상에서의 면간거리와 면간각도의 측정만으로는 상전이 여부를 명확히 구별할 수 없었다. 그러나, 결함에 의한 상변화가 900℃ 에서 심하게 관찰되어지는 것은 상전이와 관계가 있는 것으로 볼 수 있다. 고온에서 상온으로의 가역적 반응을 관찰할 수 없었던 이유는 열적산화로 생긴 산화층의 산소원자들이 고온의 상전이 과정 중에 Ti 원자와 반응이 일어나 TiO/sub X/ 구조로 전이되었기 때문으로 추정하고 있다.

• Applied Biological Chemistry
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• v.41 no.5
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• pp.367-371
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• 1998

The characteristics of four samples of noodle flours milled from Australian Standard White(ASW) wheat were compared with one sample of noodle flour prepared from a blend of hard red winter(HRW) and western white(WW) American wheats. The ASW flours had lower content of protein and ash. Farinograms revealed that the absorption of the ASW flours was slightly higher than that of the HRW-WW flour. The mixing time, however, showed no difference between ASW flours and HRW-WW flour. The stability and the mechanical tolerance index were different among ASW flours, which were lower than HRW-WW flour. The ratios of resistance to extention determined by extensigraph for ASW flours were higher except one flour than HRW-WW flour. The flours showed characteristic mean particle sizes, which may reflect the differences in hardness of wheat used in the flour production. Farinograph indices showed no correlations with protein content and extensigraph indices. The amylograph peak viscosity was inversely correlated with the protein content (p<0.05).

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.493-500
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• 2014

This paper presents findings from the assessment of the volcanic ash fragility for multi-hazard resisting vinyl greenhouse and livestock shed among the agricultural facilities. The volcanic ash fragility was evaluated by using a combination of the FOSM (first-order second-moment) method, available statistics of volcanic load, facility specifications, and building code. In this study, the evaluated volcanic ash fragilities represent the conditional probability of failure of the agricultural facilities over the full range of volcanic ash loads. For the evaluation, 6 types(ie., 2 single span, 2 tree crop, and 2 double span types) of multi-hazard resisting vinyl greenhouses and 3 types(ie., standard, coast, and mountain types) of livestock sheds are considered. All volcanic ash fragilities estimated in this study were fitted by using parameters of the GEV(generalized extreme value) distribution function, and the obtained parameters were complied into a database to be used in future. The volcanic ash fragilities obtained in this study are planning to be used to evaluate risk by volcanic ash when Mt. Baekdu erupts.