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        검색결과 1,266

        901.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        To understand the dynamical structures of stellar wind bubble, one and two-dimensional calculations has been performed. Using FCT Code with cooling effects and assuming constant mass loss rate and ambient medium density, we could divide stellar winds into the regime of slow and fast winds. The slow wind driven bubble shows initially radiative and becomes partially radiative bubble in which shocked stellar wind zone is still adiabatic. In contrast., the fast wind driven bubble shows initially fully adiabatic and becomes adiabatic bubbles with radiative outer shell. We also determine analytically the onset of thin-shell formation time in case of fast wind driven bubble with power-law energy injection and ambient density structure. We solve the line transfer problem with numerical results in order to calculate line profile of [OIII] forbidden line.
        902.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        The results of the Crab pulsar observations with the photometrical MANIA (Multichannel Analysis of Nanosecond Intensity Alterations) complex at the 6-m telescope are presented. More than 12 millions photons in UBVR-bands simultaneously with time resolution of 10-7s were detected. Using the original software for search for optical pulsar period, we obtained the light curves of the object with time resolution of about 3.3 μs. Their detailed analysis gives the spectral change during pulse and subpulse, the shape of the pulse peaks, which are plateaus (with the duration of about 50 μs for the main pulse), limits for an amplitude of fine temporal (stochastic and regular) structure of pulse and sub pulse and the interpulse space intensity. The results of CCD-spectroscopy of the Crab pulsar show that its summarized spectrum is flat. There are no lines, neither emission nor absorbtion ones. Upper limit for line intensity or depth is 3.5% with the confidence probability of 95%.
        904.
        1996.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have solved the radiative transfer problem using a Sobolev approximation with an escape probability method in case of the supersonic expansion of a stellar envelope to an ambient medium. The radiation from the expanding envelope turns out to produce a P-Cygni type profile. In order to investigate the morphology of the theoretical P-Cygni type profile, we have treated V∞, Vsto, β(parameters for the velocity field), it and E(parameter for collisional effect) as model parameters. We have investigated that the velocity field and the mass loss rate affect the shapes of the P-Cygni type profiles most effectively. The secondarily important factors are V∞, Vsto. The collisional effect tends to make the total flux increased but not so much in magnitude. We have infered some physical parameters of 68 Cyg, HD24912, and ℇ persei such as V∞, M from the model calculation, which shows a good agreenment with the observational results.
        4,500원
        906.
        1995.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        구조물의 최적설계에 대한 일반적인 개념이 제시되며 Gradient Projection법과 설계민감도 해석을 사용한 최 적 화 알고리즘이 논의된다. 6충 평면 철 골 구조물 의 최소무게 설 계의 예 를 통해 이 알고리즘의 적용올 예시 한다. 시스댐 전 체의 비용분석뿐만 아니라 임계 비용 및 설계민 감도 해석파 같은 이 알고리즘의 장점에 관하 여 설명한다3
        4,000원
        908.
        1995.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We describe the implementation of a multi-dimensional numerical code to solve the equations for idea! magnetohydrodynamics (MHD) in cylindrical geometry. It is based on an explicit finite difference scheme on an Eulerian grid, called the Total Variation Diminishing (TVD) scheme, which is a second-order-accurate extension of the Roe-type upwind scheme. Multiple spatial dimensions are treated through a Strang-type operator splitting. Curvature and source terms are included in a way to insure the formal accuracy of the code to be second order. The constraint of a divergence-free magnetic field is enforced exactly by adding a correction, which involves solving a Poisson equation. The Fourier Analysis and Cyclic Reduction (FACR) method is employed to solve it. Results from a set of tests show that the code handles flows in cylindrical geometry successfully and resolves strong shocks within two to four computational cells. The advantages and limitations of the code are discussed.
        5,700원
        909.
        1995.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        6,600원
        911.
        1995.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        4,900원
        912.
        1994.12 구독 인증기관 무료, 개인회원 유료
        5,800원
        914.
        1993.12 구독 인증기관·개인회원 무료
        919.
        1992.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, corrosion fatigue test of SAPH45 steel was performed by the use of plane bending fatigue tester in marine environment and investigated fracture surface growth behavior of base metal and heat affected zone corrosion fatigue. The main results obtained are as follows: 1) Fracture surface growth of heat affected zone (HAZ) is delayed more than that of base matel (BM), and they tend to faster in seawater than in air. 2) Corrosion sensitivity to corrosion fatigue life of HAZ is more susceptible than that of BM. 3)In the case of the corner crack by corrosion fatigue, the correlation between the propagation rate of fracture surface area(dA/dN) and stress intensity factor range(ΔK) for SAPH45 are applied to Paris rule as follows: dA/dN=C(ΔK) super(m) where m is the slope of the correlation, and is about 6.60-6.95 in air and about 6.33-6.41 in seawater respectively.
        4,000원