Five contemporary pre-main sequence (PMS) evolution model grids are compared with the photo-metric data for a nearly complete sample of low-mass members in NGC 2264. From amongst the grids compared, the models of Baraffe et al. (1998) prove to be the most reliable in mass-age distribution. To overcome the limited mass range of the models of Baraffe et al. we derived a simple transformation relation between the mass of a PMS star from Swenson et al. (1994) and that from Baraffe et al., and applied it to the PMS stars in NGC 2264 and the Orion nebula cluster (ONC). The resulting initial mass function (IMF) of the ONC shows that the previous interpretation of the IMF is not a real feature, but an artifact caused by the evolution models adopted. The IMFs of both clusters are in a good agreement with the IMF of the field stars in the solar neighborhood. This result supports the idea proposed by Lada, Strom, & Myers (1993) that the field stars originate from the stars that are formed in clusters and spread out as a result of dynamical dissociation. Nevertheless, the IMFs of OB associations and young open clusters show diverse behavior. For the low-mass regime, the current observations suffer from difficulties in membership assignment and sample incompleteness. From this, we conclude that a more thorough study of young open clusters is necessary in order to make any definite conclusions on the existence of a universal IMF.

본 연구는 하퇴의지 착용자와 정상 성인간의 시간-거리, 운동형상학 변수를 조사하고 비교하기 위하여 실시하였다. 연구 대상자는 외상으로 인한 하퇴 절단자로서 내골격식 하퇴의지를 착용하고 독립적으로 보행이 가능한 20명과 연령, 신장으로 짝짓기한 대조군(matched control group) 20명이 참여하였다. 보행분석은 Vicon Clinical Manager Software (VCM)를 내장한 PC에 5개의 카메라가 연결되어 있는 Vicon 512

As the certifications of ISO 9001/1400, OHSAS 18001(not official standard) is increasing, it is needed to construct a integrated management system(IMS) for the efficient operation. This paper deals with the types of integration of management of the various areas of interest -Quality, Environment, Safety and Health. Second, this presents how an integrated management system could be developed, implemented and operated through case studies.

Snails and slugs are members of the mollusk phylum. They are similar in biology and structure, except slugs lack the snail's external spiral shell. Snails and slugs feed on a variety of living plants, decaying plant matter, fruit, and flowers. They are among the most bothersome creatures on horticultural crops such as Chinese cabbage, cabbage, lettuce, ginseng, lily, and orchid (Kim et al., 1990; Kim, 1992; Sorensen, 1994). Several species of

창원의 단감 과수원에서 2000년 6월 하순에 해충에 의한 피해 잎에서 총채벌레를 채집하여 분류한 결과, 우리나라에서는 처음으로 보고되는 관총태벌레科(Phlaeothripidae)의 감관총채벌레(신칭)(Ponticulothrips diospyrosi)로 확인되었다. 이 종의 간략한 형태 및 생태학적 특성, 피해증상, 경남 도내에서의 분포현황을 마련하였다

A numerical scheme that incorporates a self-consistent cosmic-ray (CR, hereafter) injection model into the combined gas dynamics and CR diffusion-convection code has been developed. The hydro/CR code can follow in a very cos-effective way the evolution of CR modified shocks by adopting subzone shock-tracking and multi-level Adaptive Mesh Refinement techniques. The injection model is based on interactions of the suprathermal particles with self-generated MHD waves in quasi-parallel shocks. The particle injection is followed numerically by filtering the diffusive flux of suprathermal particles across the shock to upstream region according to a velocity-dependent transparency function, which represents the fraction of leaking suprathermal particles. In the strong shock limit of Mach numbers ≥ 20, significant physical processes such as the injection and acceleration seem to become independent of M, while they are sensitively dependent on M for M < 10. Although some particles injected early in the evolution continue to be accelerated to higher energies, the postshock CR pressure reaches a time asymptotic value due to balance between acceleration and diffusion of the CR particles.

The molecular cloud associated with the H II region S301 has been mapped in the J = 1-0 transitions of 12CO and 13CO using the 13.7 m radio telescope of Taeduk Radio Astronomy Observatory. The cloud is elongated along the north-south direction with two strong emission components facing the H II region. Its total mass is 8.7 × 10 3 M⊙. We find a velocity gradient of the molecular gas near the interface with the optical H II region, which may be a signature of interaction between the molecular cloud and the H II region. Spectra of CO, CS, and HCO+ exhibit line splitting even in the densest part of the cloud and suggests the clumpy structure. The radio continuum maps show that the ionzed gas is distributed with some asymmetry and the eastern part of the H II region is obscured by the molecular cloud. We propose that the S301 H II region is at the late stage of the champagne phase, but the second generation of stars has not yet been formed in the postshock layer.

UBV RI and Hα photometry has been performed for the open cluster NGC 6531. A total of 56 bright main sequence (MS) members were selected from their positions in photometric diagrams. We also classified 7 pre-main sequence (PMS) stars and 6 PMS candidates with Hα emission from Hα photometry. We determined a reddening of < E(B - V) >= 0.29 ± 0.03 and a distance modulus of Vo - Mv = 10.5 for the cluster. From the comparison of our photometric results to theoretical evolution models, we derived a MS turnoff age of 7.5 Myr and a PMS age spread of ~4 Myr. The IMF slope Γ, calculated in the mass range of 0.45 ≤ log m ≤ 1.35 is a steep value of Γ = -1.8 ±0.6.