• 대한기계학회논문집
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• 제15권1호
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• pp.179-189
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• 1991

본 연구에서는 특성근이 같은 같은 경우의 기본해 유도에서 사용하였던 상사 방법을 이용하여, 균열끝 부근의 응력장과 변위장을 나타내고자 한다. 위의 해석을 바탕으로 개발한 프로그램의 정도에 대하여 검증하고, 이 프로그램을 복합재료 내의 균열 문제에 응용하여 응력확대계수에 관한 자료를 계산하고, 그 유용성을 검토하고자 한다.

• Food Science and Biotechnology
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• 제14권4호
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• pp.450-455
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• 2005

This study was conducted to determine firstly the composition of the essential oil from fresh changpo (Acorus calamus var. angustatus Bess) roots quantitatively and qualitatively by use of two internal standards, and secondly volatile compounds which are primarily responsible for the aroma of changpo roots. Simultaneous steam distillation and extraction method was used for essential oil extraction, and aroma extract dilution analysis (AEDA) and sniffing test by gas chromatography/olfactometry (GC/O) were used to detect the characteristic impact odorants. According to the instrumental analysis of changpo root essential oil, cis, trans-famesol (47.56 mg/kg of fresh wt), octanoic acid (23.73 mg/kg of fresh wt), trans-2-dodecenal (20.28 mg/kg of fresh wt) and trans, trans-farnesol (13.81 mg/kg of fresh wt) were the most abundant compounds. Geranyl acetate, trans-nerolidol and trans, trans-farnesyl acetate were evaluated as the characteristic impact odorants of changpo roots from results of AEDA and sniffing test. Especially, geranyl acetate was considered as the most similar odor component to changpo roots by organoleptic evaluation with GC/O.

• International Journal of Control, Automation, and Systems
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• 제1권1호
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• pp.127-133
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• 2003

This paper proposes a new numerical method to check the stability of a general class of time delay systems. The proposed method checks whether there are characteristic roots whose real values are nonnegative through two steps. Firstly, rectangular bounds of characteristic roots whose real values are nonnegative are computed. Secondly, the existence of roots inside the bounds are checked using the numerical computation of argument principles. An adaptive discretization is proposed for the numerical computation of argument principles.

• 오토저널
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• 제12권2호
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• pp.51-58
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• 1990

According to the developments of various composite materials, it seems to be very important to evaluate the strength and fracture behavior of composite materials. When the composite material is considered as orthotropic material, the characteristic equation of orthotropic material have complex roots. If characteristic roots are equal, the fundamental solutions of BEM become singular ones. This paper analyse the fundamental solutions of the singular problem of orthotropic material using the analogous method to isotropic material.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.813-818
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• 2000

The objective of this study is to elucidate the characteristic performance of Roots-type vacuum pump with Cassini oval lobe shape. The modelled lobe shape of Roots-type vacuum pump is two-lobe spur gear. The numerical analyses are performed fer leak flows, using 4th-order Runge-Kutta method and are compared with experimental results. Results show that for the case of involute lobe shape the total amount of the leak flow conductance is greater than that of cycloid and Cassini oval lobe shapes.

• Journal of the Korean Statistical Society
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• 제31권2호
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• pp.251-259
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• 2002

Lagged regressor models with general stationary errors independent of the regressors are considered. The regressor process is unstable having characteristic roots on the unit circle. If the order of the lag matches the number of roots on the unit circle, the ordinary least squares estimator (OLSE) is asymptotically efficient in that it has the same limiting distribution as the generalized least squares estimator (GLSE) under the same normalization. This result extends the well-known result of Grenander and Rosenblatt (1957) for asymptotic efficiency of the OLSE in deterministic polynomial and/or trigonometric regressor models to a class of models with stochastic regressors.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2018년도 춘계학술대회 및 임시총회
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• pp.35-35
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• 2018

Arbuscular mycorrhizal fungi (AMF) are one of the most widespread symbionts globally. Owing to their enhanced nutrient absorption capacity, AMF significantly contribute to the survival of individual plants and the ecosystem functioning. Community structures of AMF are affected by many environmental factors Inland wetlands have a different environment from common forest soils, therefore, plants inhabiting wetlands may have characteristic AMF communities. The purpose of this study was to compare the AMF communities in wetlands, among the species of host plants. We sampled the roots of 3 host plant species, Phragmites communis, Miscanthus sacchariflorus, and Trisetum bifidum with rhizospheres from 3 isolated areas in Upo wetland, Korea. We extracted DNA from AMF spores in rhizospheres and the roots of 3 plant species. We amplified 18S rDNA of AMF using AMF specific primer. As a result, we confirmed 9 species from 5 genera in AMF spores, and 5 species from 3 genera in plant roots. Funneliformis caledonium was the most dominant species in field soils, on the other hand, Diversispora aurantia was the most dominant species in plant roots. We confirmed that species diversity and abundance of AMF communities were different among host plant species. These results showed that the AMF community had specific to host plants in the inland wetland.

• 한국균학회지
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• 제38권1호
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• pp.1-4
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• 2010

광릉요강꽃(Cypripedium japonicum)과 복주머니란(C. macranthum)의 뿌리에서 난 균근균이 확인되었다. 두 종의 난 뿌리에서 균근의 형태적인 특성을 관찰하였다. 분자적인 분석을 통하여 두 종의 뿌리로부터 난균근균을 확인하였다. 뿌리에서 DNA를 추출하여, 담자균류 ITS 지역에 특이적인 프라이머인 ITS1-OF와 ITS4-OF를 사용하여 ITS 지역을 증폭한 후 염기서열을 분석하여 두 식물의 뿌리에 공생하는 난균근균을 동정하였다. 광릉요강꽃의 뿌리에는 3종류의 Tulasnellaceae와 1종의 담자균류가 발견되었고, 복주머니란의 뿌리에서는 2종류의 Tulasnellaceae에 속하는 균이발견되었다.

• 약학회지
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• 제10권2_3호
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• pp.1-4
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• 1966

Pterygopleurum Neurophyllum $K_{ITAGAWA}$ was a kind of new recorded perennial herbs in Korea; The roots are consisted of two parts, mother tuber and daughter tuber. There are characteristic deferences in histological structure between mother tuber and daughter tuber.

• 한국소음진동공학회논문집
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• 제21권12호
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• pp.1112-1119
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• 2011

The goal of this study is the stability evaluation of a vacuum pump through modal test and rotor dynamics. Roots type vacuum pump, which is a dry vacuum pump, is necessary for the manufacturing process of the semiconductor and the display. Eigenvalue was solved by the finite-element method(FEM) using 2D and 3D models, then the modal test result was compared with the FEM result. According to the comparison, the analysis result using the 2D was more accurate than the 3D model. Therefore, rotor dynamics was performed by the 2D model. Campbell diagram and root-locus maps, which were calculated by complex-eigenvalue analysis, were used to evaluate the stability of the rotors of the vacuum pump. And displacement solved by unbalance response analysis was compared with the minimum clearance between two rotors of the vacuum pump. Thus, the vacuum pump is assumed operated under steady state through the evaluation of the rotor dynamics.