• Journal of Microbiology
• /
• 제40권1호
• /
• pp.55-62
• /
• 2002

Biodiversity af yeasts in various natural environments including soils, swamps and plants was investigated. By molecular identification methods based on the partial sequences of 265 rDNA, 69 isolates were assigned to 44 taxa including 27 known species. The remaining 17 taxa could potentially form new species. All of them were classified into Ascomycota, Hymenomycetes, Urediniomycetes and Ustilaginomycetes. Ascomycetous and ustilaginomycetous yeasts were generally isolated from flower samples, and hymenomycetous and urediniomycetous yeasts were generally isolated from soil samples. Distribution of yeast groups exhibited geographical variation. Yeast biodiversity of root sail also varied according to the associated plant species.

• 한국군사과학기술학회지
• /
• 제7권4호
• /
• pp.114-124
• /
• 2004

In this paper, we have proposed a novel method which can analysis a rotating elastically restrained blade with concentrated masses located in an arbitrary position. 1:he equations of motion are derived and transformed into a dimensionless form to investigate general phenomena. For the modeling of the multi-concentrated masses, the Dirac delta function is used for the mass density function. Simulation results show that the vibration characteristics of elastic restrained blade of according to dimensionless variables for example, multiple masses magnitude and mass location ratio. This method can be applied to an practical rotating blade system required to more accurate results.

• 한국군사과학기술학회지
• /
• 제6권4호
• /
• pp.100-112
• /
• 2003

This paper presents the transient response analysis of a rotating blade in resonant frequency range. It is shown that the modeling is considered in elastic foundation and friction damping effect. The equations of motion are derived and transformed into a dimensionless form to investigate general phenomena. Numerical results show that the magnitude of friction damping to reduce maximum transient response in near the critical angular speed. The method can be applied to a number of examples of the practical rotating blade system to minimize transient response in resonant frequency range.

• 전기학회논문지
• /
• 제60권8호
• /
• pp.1547-1554
• /
• 2011

As process parameters scale, interconnect width are reduced rapidly while the current flowing through interconnects does not decrease in a proportional manner. This effect increases current density in metal interconnects which may result in poor reliability. Since RMS(root-mean-square) current limits are used to evaluate self-heating and short-time stress failures caused by high-current pluses, RMS current estimation is very important to guarantee the reliability of semiconductor systems. Hence, it is critical to estimate the current limits through interconnects earlier in semiconductor design stages. The purpose of this paper is to propose a fast, yet accurate RMS current estimation technique that can offer a relatively precise estimate by using closed-form equations. The efficiency and accuracy of the proposed method have been verified through simulations using HSPICE for a vast range of interconnect parameters.

• 한국정보전자통신기술학회논문지
• /
• 제3권3호
• /
• pp.8-13
• /
• 2010

Shape from focus (SFF) 방법은 이미지의 초점화된 영상을 이용하여 삼차원의 형상을 복원하는 방법이다. 그동안 많은 SFF 방법들이 연구되어 왔지만 노이즈에 대한 문제점과 영상특성으로 인한 최적화되지 못한 문제점이 남아있었다. 그러므로 노이즈를 제거하기 위한 필터링과 최적화 알고리즘을 제안한다. 성능 평가를 위하여 통계적인 판별기준인 평균제곱근오차 (RMSE)와 상관관계 (correlation) 수치를 이용한다.

• Earthquakes and Structures
• /
• 제8권5호
• /
• pp.1055-1067
• /
• 2015

A theoretical procedure to estimate spectral displacement of a hysteretic oscillator with bilinear stiffness excited by band-limited excitation is presented. The stochastic method of ground-motion simulation is combined with the random vibration theory to compute linear and nonlinear structural response. The response is obtained by computing the root-mean-square oscillator response using dissipation energy balancing by integrating over all energy levels of system weighting with the stationary probability density of the energy. The results are presented in a convenient form, and the accuracy of the procedure is assessed by comparison with results obtained with the time-domain method using the recorded data. The model shows little or no bias at the structural period of engineering interest.

• 한국농촌건축학회논문집
• /
• 제4권2호
• /
• pp.27-37
• /
• 2002

From the point of tectonic manner which is 'how to build a house' this study considers the characteristics of Kan in Hyangdan(香壇) at Yang-Dong Village. It was analysed with primary elements such as Kan, condition of a site, module, structural system, roofing system and their relationships in spatial and formal composition. Through the analysis, findings were achieved that characteristics of Kan to form a rectangle of 1 to root 2 proportion plan, enable irregularity in usage and regularity in compositional aspect and structural system to achieve intended roof design. In addition, Kan as a module is found to have a relative value that also regulates the whole in structural and aesthetical aspects.

• 약학회지
• /
• 제6권1호
• /
• pp.21-24
• /
• 1962

A report is given of microscopic study of the root Angelica gigas Nakai comparing with Ligusticum acutilobum S. et Z.(=Angelica acutiloba Kitagawa). The following characteristics are outstanding. 1. Angelica gigas Nakai is more tender and softer than Ligusticum acutilobum S. et Z. 2. Both Angelica gigas Nakai and Ligusticum acutilobum S. et Z. are alike in the form and arrangement of fundamental parenchyma in cortex and xylem. 3. No mechanical tissues are present but the substitute fibers in the Angelica gigas Nakai and Ligusticum acutilobum S. et Z. 4. The intercellular space are more numerous and larger in Angelica gigas Nakai than in Ligusticum acutilobum S. et Z. 5. Secretory tissue in Angelica gigas Nakai consists of numerous canals while in Ligusticum acutilobum S. et Z. very few.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년도 학술대회
• /
• pp.251-255
• /
• 2008

Flow field around helicopter involves incompressible flow near the blade root and compressible flow at the blade tip. A problem occurs for low Mach number flow due to the stiffness of the governing equations. Time-derivative preconditioning techniques have been incorporated to reduce the stiffness that occurs at low speed region. The preconditioned form of the compressible Navier-Stokes and Euler equations is used. Computations are performed for the Caradonna-Tung's hovering and non-lifting forward flight case. Computational results are in good agreement with the experimental data.

• 대한기계학회논문집
• /
• 제14권2호
• /
• pp.288-297
• /
• 1990

The method of analyzing flexible mechanisms with clearances was studied considering flexibility of beams in the mechanism using finite elements. Both ends of a beam were modeled as free following Dubowsky's impact pair model. Instead some force constraints were imposed at imposed at the connections between adjoining links. Coulomb model has been developed using dry frictions in place of tangential damping forces in the impact pair model and the contact compliance and damping coefficient approximated in a form of root function were used. As examples, impacts of a rigid ball in a cylinder, impact beam model and four-bar mechanisms made up of three flexible links with clearance connections were simulated numerically. The results from examples showed similar but a little bit smaller magnitude of impact forces compared with published studies.