• 한국산림과학회지
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• 제96권2호
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• pp.189-196
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• 2007

Allometry, basal area equations, and volume equations were developed with various tree measurement variables for the major species, Quercus mongolica and Quercus variabilis, in Korean natural hardwood forests. For allometry models, the relationships between total height-DBH, crown width-DBH, height to the widest portion of the crown-total height, and height to base of crown-total height were investigated. Multiple regression methods were used to relate annual basal area growth to tree variables of initial size (DBH, total height, crown width) and relative size (relative diameter, relative height) as well as competition measures (competition index, crown class, exposed crown area, percent exposed crown area, live crown ratio). For tree volume equations, the combined-variable and Schumacher models were fitted with DBH, total height and crown width for both species.

• 한국해양공학회지
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• 제8권2호
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• pp.115-123
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• 1994

Under variable amplitude loading conditions, retardation or accelerated condition of fatigue crack growth occurs with every cycle, Because fatigue crack growth behavior varied depend on load time history. The modeling of stress amplitude with storm loading acted to ships and offshore structures applied this paper. The crack closure behavior examine by recording the variation in load-strain relationship. By taking process mentioned above, fatigue crack growth rate, crack length, stress intensity factor, and crack closure stress intensity factor were obtained from the stress cycles of each type of storm ; A(6m), B(7m), C(8m), D(9m), E(11m) and F(15m) which was wave height. It showed that the good agreement with between the experiment results and simulation of storm loads. So this estimated method of crack propagtion rate gives a good criterion for the safe design of vessels and marine structure.

• KSBB Journal
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• 제6권2호
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• pp.189-194
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• 1991

The effect of wtlitc light on unaeraten growth of Baker's yeast and the accompanying ethanol production has been studied in a batch process at 27$^{\circ}C$. Over the 80-hour period of the Champagne yeast process without pH control, the cull growth was inhibited by the fluorescent light. Another observed difference between the runs is that the drop and subsequent rise in redox potential occurred much sooner in the fermentation with light than in the fermentation without light. This preliminary study indicated that ethanol production could be enhanced by light as the cell concentration is repressed. The possible pathway, shift of the sugar substrate toward ethanol and away from cells was manifested by another difference as well. As observed under the microscope, many of the yeast cells grown under light budded without dividing by the normal fission process as they did in the dark. Furthermore, the undivided and branched (light grown) cell did not agglutinate at the end of the fermentation process as did the distinct spherical (dark grown) cells.

• 대한수학회보
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• 제60권6호
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• pp.1673-1685
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• 2023

Inspired by Hongjie Dong and Qi S. Zhang's article [3], we find that the analyticity in time for a smooth solution of the heat equation with exponential quadratic growth in the space variable can be extended to any complete noncompact Riemannian manifolds with Bakry-Émery Ricci curvature bounded below and the potential function being of at most quadratic growth. Therefore, our result holds on all gradient Ricci solitons. As a corollary, we give a necessary and sufficient condition on the solvability of the backward heat equation in a class of functions with the similar growth condition. In addition, we also consider the solution in certain L^p spaces with p ∈ [2, +∞) and prove its analyticity with respect to time.

• 한국생산제조학회지
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• 제8권2호
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• pp.126-136
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• 1999

We studied on crack growth retardation in single overloading condition. Crack tip branching which as the second mechanism on crack growth retardation was examined. Crack tip branching was observed to kinked type and forked type. It was found that the branching angle range was from 25 to 53 degree. The variations of crack driving force with branching angle were calculated with finite element method The variation of {{{{ KAPPA _I}}}}, {{{{ KAPPA _II}}}} and total crack driving force(K) were examined respectively So {{{{ KAPPA _I}}}}, {{{{ KAPPA _II}}}} and K mean to mode I, II and total crack driving force. Present model(Willenborg's model) for crack growth retardation prediction was modified to take into consideration the effects of crack tip branching When we predicted retardation with modified model. it was confirmed that predicted and experimental results coincided with well each other.

• 동아시아식생활학회지
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• 제16권3호
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• pp.344-348
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• 2006

This study was carried out to survey the effect of medicinal herbs on the growth of 3 strains of lactic starter cultures in MRS broth by the addition of 0, 1, 3, 5, and 10% water extract, after 30 hrs incubation. The pH, titratable acidity and O.D. of lactic acid bacteria were investigated to obtain fundamental knowledge for the development a new product. The effects of medicinal herbs extracts on the growth of lactic acid bacteria were variable depending upon the species of lactic acid bacteria and medicinal herbs extract. Growth of Str. thermohilus was activated by addition of 1 and 3% Angelica gigas water extract, but the basal medium plus 5 and 10% extract and growth of L. acidophilus and Bif. longum were depressed by the addition of extract. The pH and acid production ability dropped slightly in the basal medium plus 1 and 3% of extract. The other samples following the same trend as the control.

• 무역학회지
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• 제41권4호
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• pp.41-59
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• 2016

한 국가의 기업가정신이 경제성장에 기여하는 영향요인으로 주목받고 있는 상황이다. 본 연구는 기업가정신을 기업가적 행동과 환경으로 세분화하여 이들이 국가의 경제성장에 미치는 영향에 대하여 분석하고자 하였다. 기존 연구에서는 기업가정신이라는 변수를 중심으로 경제성장과의 관계성을 분석하였다면, 본 연구에서는 기업가적 활동과 기업가적 환경이라는 변수를 이용하여 극가들의 경제성장에 미치는 영향을 설명하고자 하였다. 더 나아가, 무역과 혁신이 제시된 독렵변수들과 경제성과와의 관계에서 조절적 역할을 수행하는 지를 검증하고자 하였다. GEM의 Adult Population Survey(APS)와 National Expert Survey(NES), World bank에서 데이터를 수집하여 패널분석을 실시한 결과, 기업가적 행동과 기업가 환경요인은 모두 혹은 부분적으로 국가별 경제성장에 유의한 정의 영향을 미치는 것으로 분석되었다. 특히, 기회추구형 창업활동이 경제성장에 정의 영향을 주는 것으로 나타나 창업활동의 질적인 측면이 경제성장의 성과로 이어지는데 중요한 변수임을 도출하였다. 또한, 정부 창업 지원프로그램과 경제성장의 관계에 대하여 무역과 혁신이 유의하게 조절효과를 갖는 것을 확인하였으며, 본 연구 결과에 따른 시사점에 대하여 논의하였다.

• 지역연구
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• 제31권4호
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• pp.71-90
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• 2015

본 연구는 R&D 사업의 효과분석을 위해서는 기간별 성과를 비교하며 분석하는 것이 당해 연도 성과만을 분석하며 비교하는 것보다 타당하다는 연구문제에서 출발한다. 이에 개별 기업이 지니는 성과 특성을 시계열 자료의 종적 비교 분석을 통해 기간에 따라 파악함으로써 지역연구개발사업의 효과를 입체적으로 파악하고 있다. 기업의 성과에 대한 객관적인 평가를 위해서 해당 R&D 사업 참여 기업의 매출액과 영업이익을 핵심변수로 하여 R&D 예산 투자의 경제적 성과를 중심으로 파악하고자 하였다. 경제적 성과에 대한 분석을 위해 Within 분석을 '기업 내 효과 분석'으로 조작적 정의(operational definition)하였으며 이를 토대로 국가 R&D 투자효과를 측정을 위한 방법론을 설정하였다. 분석결과 전기효과가 후기효과에 비해 큰 것으로 나타났으며 이는 지역R&D투자에 따른 성과가 지원기간 이후까지 지속되기보다 지원기간에 한시적으로 나타남을 의미한다.

• KSBB Journal
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• 제24권1호
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• pp.17-24
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• 2009

For the biosurfactant production process at first Candida bombicola, Sphingomonas yanoikuyae, Sphingomonas chungbukensis and Myxococcus flavescens were studied. As the most productive microorganisms C. bombicola, S. yanoikuyae and S. chungbukensis were selected. During many petrochemical industrial processes variable volatile organic componds are produced and they can cause an unpleasent and unhealthy atmosphere. Usually the volatile organic compounds are treated with chemical detergents. The chemical detergents cannot be easily degradable and can be accumulated in the nature. In this study we tried to develop a production process for the biosurfactants, which can substitute some chemical detergents in some chemical processes, with microorganisms. At second the treatment of the volatile organic compounds with the biosurfactants were tested and compared with the treatment with chemical detergent. The production productivities of the biosurfactant with microorganisms were compared. The growth patterns and kinetics of the microbial cells and the surface tension values of the biosurfactants were studied. The changes of the surface tension in variable pH conditions and sodium chloride concentrations were also studied. The volatile organic carbons were treated in a small plant scale. As the result of this study, it indicated that the specific growth rate of S. chungbukensis was the fastest by 0.144 ($hr^{-1}$). For surface tension, C. bombicola (38.1 dyne/cm) had the lowest value, and solubility of the volatile organic carbon was similar in C. bombicola and S. chungbukensis. (Toluene: about 0.1 Unit, Chloroform: about 0.6${\sim}$0.7 Unit, Benzene: about 0.5${\sim}$0.8 Unit). The biosurfactant, which were produced by C. bombicola, was selected for the further study for the volatile organic carbon treatment. With the biosurfactans from C. bombicola could remove the volatile organic carbon about 80% and this removal rate can be comparable with chemical detergent.

• 대한기계학회논문집A
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• 제28권3호
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• pp.281-288
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• 2004

The hybrid composite material (Al/GFRP laminates) are applied to the fuselage and wing in a aircraft. Therefore, Al/GFRP laminates suffer from the cyclic bending moments. This study was to evaluate the effect of fiber stacking angle on the fatigue crack propagation and delamination behavior using the relationship between crack growth rate (da/dN) and stress intensity factor range (ΔK) in Al/GFRP laminates under cyclic bending moment. The variable delamination growth behavior in case of three different type of fiber orientations, i.e., [Al/O$_2$/Al], [Al/+45$_2$/Al] and [Al/90$_2$/Al] at the interface of Al layer and glass fiber layer was measured by ultrasonic C-scan images. As results of this study, It represent that the delamination shape should turns out to have more effective characteristics on the fiber stacking angle. The extension of the delamination zone in case of [Al/+45$_2$/Al] and [Al/90$_2$/Al] were not formed along the fatigue crack profile. The shape of delamination zone depend on fiber stacking angle and the variable type with the delamination contour decreased non-linearly toward the crack tip at the Al layer.