We report a high resolution spectrum of AG Pegasi observed at Bohyunsan Optical Astronomy Observatory (BOAO) on October 2, 2004. Some of permitted emission lines, for example H I, He I, He II, Fe II and Ti II were observed in the spectrum of AG Pegasi in 2004. Lines presented in the longer wavelength region than 6500＼AA are identified. And radial velocities for each element are measured. Then we carefully discuss the geometrical feature of AG Pegasi in October 2004.

We plan to install the polarimetric optics in the AGU(acqusition and guiding unit) of the 1.8 m telescope at the BOAO(Bohyunsan Optical Astronomy Observatory). With this, the spectropolarimetric observations with the resolution of 45,000 and 60,000 in 4,000 to 8,000＼AA ange could be done by the BOES(BOao Echelle Spectrograph). If we use the precision radial velocity measurement capability of the BOES, the accuracy of the magnetic field intensity measurements with this new BOES stokesmeter will be much increased. We present here the design concept of the BOES stokesmeter. Some details on the optics, mechanical parts, fiber parts and the lab test procedures of this stokesmeter are explained.

We present a high resolution spectrum of PU Vul observed at Bohyunsan Optical Astronomy Observatory (BOAO) on April 9, 2004. Permitted emission and nebular lines of PU Vul had been significantly changed compared to all spectra observed since its eruption in 1979. Therefore all new lines should be re-identified and were done so. We do-convoluted a Hβ line into several emission components with Gaussian functions. Then we carefully discussed the geometrical feature of PU Vul in April 2004.

The problem for the collapse of isothermal and rotational self-gravitational viscous disk is considered. We derive self-similar solutions for the cases in the inner and outer regions of the self-gravitational viscous disk. We show that surface density depends on σ0/r in the outer region of the disk using a slow accretion approximation. The ratio of a modified viscous parameter in the outer region of the disk to that in the inner region is 0.042. We resorted to numerical solutions of governing equations of the self-gravitational disk to find out profiles of σ, u and υ in terms of x. Their profiles were rapidly changed around the innermost region of the self-gravitational disk. It indicates that a new object was formed in the most inner region of the disk.

The problem of the collapse of a self gravitating disk is here considered. We show self-similar solutions for the above problem under a modified viscous parameter. Surface density depends on rm in the inner region, where m is -1.6. Therefore growing central mass goes on without mass inflow to the system.

Our examination of the relations of spherically symmetric accretion on a massive point object to viscous drag, neglecting gas pressure and using self-similar transformation, shows the behaviors of the asymptotic solutions? in the regions near to and far from the center. The viscosity reduces the free-fall velocity by the factor (1+ζ)−1, and causes flattening in the density distribution. Therefore, the viscosity leads to the reduction of the mass accretion rate.

점성과 충돌이 있는 강착원반의 확산 과정을 생각한다. 이때 확산계수는 단순하게 1/√r로 비례한다. 강착원반의 난류에 의해서 각운동량은 외부로 수송된다. 파동도 또한 내부에서 외부로 전달되므로 강착원반은 불안정한 방향으로 진행된다.

The collision effects in particles of the accretion disk are examined by the use of small perturbation. The collision force is assumed to be equal to 2 vV. From the equations governing collisions of such particles the local dispersion relation is obtained.

The time-dependence of an α-disk model under the influence of collisions of particles is examined. Collisions with viscosity tend to take away angular momentum. Both effects cause the disk to rotate more rapidly. The disk gradually contracts with increasing time.

본 연구의 목적은 STS프로그램을 적용한 수업이 학생들의 과학에 관련된 태도와 과학학습성취도에 미치는 효과를 분석하는데 있다. 연구 목적에 따라 고등학교 3학년 학생들을 실험집단과 통제집단으로 나눈 뒤, 약 6주 동안 실험집단은 본 연구자가 개발한 STS 프로그램을 사용하여 수업을 실시하고 통제집단은 강의 중심의 전통적 수업을 실시하였다. 연구 결과 과학에 관련된 태도에 있어 실험집단이 통제 집단보다 더 긍정적인 방향으로 태도가 향상되었고, 과학학습 성취도에 있어서도 실험집단이 더 높은 성취도 향상을 나타내었다.