Normal development of human fetal teeth during prenatal period play an important role in analyzing abnormal teeth formation and examining pathologic approach to abnormal teeth formation. The purposes of this study were to describe the normal development of dental hard tissues in fetal teeth compared to abnormal teeth formation through review and literature. We will apply these study to examine the pathologic alterations of human teeth in the future.

We introduce and describe performance of the 6-meter telescope of Seoul Radio Astronomy Observatory (SRAO). All the softwares and instruments except the antenna structure and its driving system are developed for ourselves. The SIS mixer type receiver resulted in the receiver noise temperature less than 50 K (DSB) over the whole 3-mm radio window. An autocorrelation spectrometer, developed first in Korea, provides maximum 50 MHz band width over 1024 channels. Antenna surface is measured and adjusted using template method and radio holography which resulted in a superb surface accuracy bet-ter than 30μm. Accordingly, the aperture and beam efficiences amount to 70% and 75%, respectively, largely independent of frequency in the 85 - 115 GHz range. It is also found that telescope pointing errors are less than 10" in both azimuth and elevation and that antenna gain is almost constant against elevation greater than 20°, without adjusting sub-reflector position. The SRAO 6-meter telescope is now fully operational and all these characteristics verify that observations are carried out with high precision and fidelity.

We present Near-IR photometry of the Arches cluster, a young and massive stellar cluster near the Galactic center. We have analyzed the high resolution (FWHM ~ 0.2") H and K" band images in the Galactic Center Demonstration Science Data Set, which were obtained with the Gemini/Hokupa's adaptive optics (AO) system. We present the color-magnitude diagram, the luminosity function and the initial mass function (IMF) of the stars in the Arches cluster in comparison with the HST/NICMOS data. The IMF slope for the range of 1.0 < log (M/M⊙) < 2.1 is estimated to be Γ = -0.79 ± 0.16, in good agreements with the earlier result based on the HST/NICMOS data [Figer et al. 1999, ApJ, 525, 750]. These results strengthen the evidence that the IMF of the bright. stars close to the Galactic center is much flatter than that for the solar neighborhood. This is also consistent with a recent finding that the IMFs of the bright stars in young clusters in M33 get flatter as the galactocentric distance decreases [Lee et al. 2001, astro-ph 0109258]. It is found that the power of the Gemini/ AO system is comparable, with some limits, to that of the HST/NICMOS.

The main objective of this paper is to analyze the r('ctangular stiffened plates with two opposite ends elasti cally restrained and t he others simply supported subjected to in-plane bending by Finite Element κ1ethod. Another objecti ve is to develope Classical Method analyzing the unstiffened rectangular plates with the above boundary conditions. In order to validate finite element and classical methods, the buck , ling strengths of the rectangular plates with four simply supported ends, and with two simply supported and the others fixed ends by fini te element method and classical method are compared with those of references. In finite element method, elas tically restrained ends can be obtained as considering torsional and warping rigidities of end stiffeners. The buckling strengths of the rectangular plates with elastically restrained ends by finit e element and classical methods are calcu lated and compared with each other.In case of stiffened plates, to validate finite elernent rnethod, the buckling strengths of the rectangular stiffened plates with four sirnply supported ends, and with two sirnply supported and the others fixed ends are also cornpared with those of references. The buckling strengths of the rectangular stiffened plates with elastically restrained ends by finite elernent rnethod are calculated as solving eigenvalue problerns which are obtained as assernbling rectangular plate elernents and bearn elernents considered torsional and warping rigidities. The buckling strengths of rectangular stiffened plates according to various positions of rectangular intermediate stiffener, J and 1" of end stiffeners are also obtained, which are cornpared to deterrnine the efficient position of interrnediate stiffener.

We present UBVRI CCD photometry of the Type Ie supernova SN 19941 in M51 which was discovered on April 2, 1994 (UT). UBVRI CCD photometry of SN 1994 I were obtained for the period of the first two months from April 4, 1994, using the Seoul National University Observatory 60 cm telescope. The light curves of SN 19941 show several interesting features: (a) SN 19941 reaches the maximum brightness at B-band on April 8.23 (B = 13.68 mag), at V-band on April 9.10 (V = 12.89 mag), and at I-band on April 10.32 (I = 12.48 mag); (b) The light curves around the maximum brightness are much narrower than those of other types of supernovae; (c) The light curves after the peak decline more steeply than those of other types of supernovae; and (d) The colors get redder from (V-R) ≈ 0.2 mag ((V - I) ≈ 0.3 mag, (B - V) ≈ 0.7 mag) on April 4 to (V-R)≈ 0.6 mag ((V-1) ≈0.9 mag, (B-V) ≈ 1.3 mag) on April 18. Afterwards (V - R) colors get bluer slightly (by ~0.005 mag/day), while (V-I) colors stay almost constant around (V-1) ≈ 1.0 mag. The color at the maximum brightness is (B-V)=0.9 mag, which is ~1 mag redder than the mean color of typical Type la supernovae at the maximum brightness. The light curves of SN 1994I are similar to those of the Type Ie supernova SN 1962L in NGC 1073. Adopting the distance modulus of (m-M)0 = 29.2 mag and the reddening of E(B - V) = 0.45 mag [Iwamoto et al. 1994, preprint for ApJ], we derive absolute magnitudes at the maximum brightness of SN 1994I, Mv(max) = -17.7 mag and MB(max) = -17.4 mag. This result shows that SN 1994I was ~2 mag fainter at the maximum brightness compared with typical Type Ia supernovae. A narrower peak and faster decline after the maximum in the light curve of SN 1994I compared with other types of supernovae indicate that the progenitor of SN 1994I might be a lower mass star compared with those of other types of supernovae.

One of the problems facing international companies is the question of whether to use standardized international advertising or to adapt advertising messages in each country. This paper provides empirical evidence for whether or not to be able to use standardized advertising based on a comparison of evaluative criteria for automobiles and toothpaste among American, Japanese, and Korean consumers. There appears to be a similar pattern among respondents of the three countries in rank of attribute importance. Especially, the result of toothpaste shows an almost identical pattern. The findings do support the idea that international advertising can be standardized due to the similarities among world-wide consumers.

Slow seedling growth rate and nodulation failure of white clover (Trifolium repens L.) has been limited its good establishment to pastures. The experiment was done to determine the effect of removal of cotyledon and unifoliolate on the shoot, root growth,

Two perforated plates(a square plate and a rectangular plate having an as야ct ratlO 1.57(L,=11, L,= 7)) are taken as analysis examples. Each of these plates is given some changes in the boundary ∞nditions. The size of cutouts as well as their locations are also changed in order to examine the variation of two eigenvalues corresponding to the fundamental mode. The relationship between two eigenvalues is estab!ished by changing the magnitude of edge thrust

2차원인 유한요소들을 각 절점에서 6개의 자유도를 갖는 3차원언 업체호 결함함으로서， 횡하중을 받 고있는 합성 젤 구조를 해석할 수 있는 프로그랩 [MSSLL]을 개발하였다. 전체 구조물이 여러개의 반복 되는 Substructure들로 이루어졌을 때에는， 인력의 소모를 극소화 하고 계산시간을 절약할 수 있도록 해석과정에 Substructuring 기법을 본 프로그램에 도입하였다. 프로그램의 신뢰도를 확인하기 위하여 본 프로그램에 의한 해석결과와 다른 방법에 의한 결과를 비교분석 하였으며， 지진력을 받고있는 8 개의 개별 원추뜰로 구성된 웰 구조의 거동에 대한 높이-경간비의 영향을 규명하기 위하여 변수연구를 수 행하였다.

According to the star formation rate and metal enrichment rate given by the disk-halo model of Lee and Ann (1981), the two different forms of time-dependent initial mass function (IMF) and the present day mass function (PDMF) of nearby stars have been examined. It was shown that the constraint for the initial rapid metal enrichment requires the time-dependence of IMF at the very early phase ( t ≲ 5 × 10 8 yrs) of the solar neighborhood. The computed PDMF's show that the PDMF is nearly independent of any specific functional form of IMF as long as the latter includes a Gaussian distribution of log m. This result is due to the very small fractional mass ( × 5 of stars formed at the very early period during which the IMF is time-dependent. The computed PDMF suggests the presence of more numerous low mass stars than shown in Miller and Scalo's (1979) PDMF, supporting the possibility of the existence of low-velocity M dwarfs. According to the number distribution of stars with respect to [Fe/H], the mean age of these low mass star must be very old so as to yield the mean metal abundance ¯ [ F e / H ] ≈ − 0.15 for the stars in the solar neighborhood.