Expression of STAT3 downstream genes in mouse embryonic stem cells

Thesis(masters) --서울대학교 대학원 :생명과학부,2008. 8.Maste

The Current Status and Management Problems of Street Trees in the Republic of Korea

This study aims to assess the current status of street trees in the Republic of Korea and to identify the main problems in managing them. The managers of street trees and professionals in urban horticulture and forestry fields were asked to fill out questionaries addressing the management of street trees. As of the end of year 1991 were there 2 millions of street trees planted in South Korea, with 46% of them in the cities and the rest along the rural roads. There were 70 tree species planted along the streets including 27 native species. The species composition biased towards exotic species was identified as one of the major problems in the regional environmental policy. This is probably due to the moriotonic pattern of public administration lacking of independent authorities in provincial or municipal governments. Therefore, now with the newly introduced regional government system, the street trees should be managed in a varied manner according to the regional environment. To improve the efficiency in monitoring the management of street trees, a computer based information system of street trees management is strongly recommended.이 연구는 1991년도 과학재단 목적기초연구비의 지원으로 이루어졌음

Experimental Validation of Ornithopter Aerodynamic Model in Low Reynolds Number Regime

본 연구에서는 날갯짓 비행체 날개의 유체-구조 연계를 고려한 설계나 날갯짓 비행체의 비행 동역학 및 제어 시뮬레이션에 적용 가능한 효율적인 공력모델을 제안하고, 풍동실험을 통해 공력모델의 특성을 검증하고자 한다. 날갯짓 비행체는 저 레이놀즈 수 영역의 비정상 유동장의 지배를 받기 때문에, 이 영역에서 날개 운동에 따른 공력을 효과적으로 측정할 수 있도록 풍동실험장치를 설계 및 개발하였다. 본 연구의 실험장치 특성상 힘을 측정하는 2축-로드셀은 비관성계에 있기 때문에, 순수한 날개의 공력을 측정하기 위해서는 관성력을 보정해주어야 하며, 이에 대한 방법론을 수립하였다. 최종적으로 유동속도, 날개의 운동 주파수 및 고정 받음각에 따라 날개에 작용하는 양력 및 항력의 평균값 및 평균 제곱근 값을 비교함으로서 실험결과와 공력모델의 특성을 비교 검증하였다.이 논문은 2007년 정보(교육인적자원부)의 재원으로 한국학술진흥재단의 지원을 받아 수행된 연구임(KRF-2007-313-D00122)

Model Establishment of a Deployable Missile Control Fin Using Substructure Synthesis Method

A deployable missile control fin has some structural nonlinearities because of the worn or loose hinges and the manufacturing tolerance. The structural nonlinearity cannot be eliminated completely, and exerts significant effects on the static and dynamic characteristics of the control fin. Thus, it is important to establish the accurate deployable missile control fin model. In the present study, the nonlinear dynamic model of the deployable missile control fin is developed using a substructure synthesis method. The deployable missile control fin can be subdivided into two substructures represented by linear dynamic models and a nonlinear hinge with structural nonlinearities. The nonlinear hinge model is established by using a system identification method, and the substructure modes are improved using the Frequency Response Method. A substructure synthesis method is expanded to couple the substructure models and the nonlinear hinge model, and the nonlinear dynamic model of the fin is developed. Finally, the established nonlinear dynamic model of the deployable missile control fin is verified by dynamic tests. The established model is in good agreement with test results, showing that the present approach is useful in aeroelastic stability analyses such as time-domain nonlinear flutter analysis.

4개의 페르미온 이론에서의 동력학적으로 깨어진 카이랄 대칭성의 회복

학위논문(박사) - 한국과학기술원 : 물리학과, 1995.8, [ iv, 83 p. ]We examine four-fermion theory to investigate the restoration of dynamically broken chiral symmetry by varying some parameters of a system: the coupling constant, spacetime topology (finite temperature and size) and curvature, and particle-number density. Four-fermion systems have rich vacuum structures. The ground structure is composed of fermion-antifermion pairs, and chiral symmetry is dynamically broken for large values of coupling constant; therefore, they have some analogy to the low-energy theory of QCD and BCS theory of superconductivity. We investigated two kinds of four-fermion model, Gross-Neveu model and Nambu and Jona-Lasinio model in the toroidal spacetime. The Gross-Neveu model has also been analyzed in a spherical spacetime at finite-chemical potential, which is related to the fermion-number density. Then, critical values of coupling constant, toroidal dimensions, spacetime curvature, and chemical potential have been derived, at which the dynamically broken chiral symmetry is restored, and the dynamically acquired fermion mass becomes zero, and fermions begin to decouple. Additionly, sine-Gordon theory is investigated on the torus. Critical temperatures have been obtained as a function of finite size, at which the system becomes unstable.한국과학기술원 : 물리학과

Modified Strip Theory를 이용한 플래핑 날개 비행체의 공기역학 모델

KOSE

플래핑 운동을 위한 IPMC 작동기 모듈 개발에 관한 연구

KOSE

IPMC 작동기의 기계적 물성에 관한 연구

KOSE