• Bulletin of the Korean Space Science Society
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• 2006.10a
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• pp.33-33
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• 2006

• East Asian mathematical journal
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• v.32 no.3
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• pp.365-375
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• 2016

In this paper, we study some classes of spaces determined by closure-like operators $[{\cdot}]_s$, $[{\cdot}]_c$ and $[{\cdot}]_k$ etc. which are wider than the class of $Fr{\acute{e}}chet-Urysohn$ spaces or the class of sequential spaces and related spaces. We first introduce a WADS space which is a generalization of a sequential space. We show that X is a WADS and k-space iff X is sequential and every WADS space is C-closed and obtained that every WADS and countably compact space is sequential as a corollary. We also show that every WAP and countably compact space is countably sequential and obtain that every WACP and countably compact space is sequential as a corollary. And we show that every WAP and weakly k-space is countably sequential and obtain that X is a WACP and weakly k-space iff X is sequential as a corollary.

• Bulletin of the Korean Mathematical Society
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• v.26 no.2
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• pp.159-164
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• 1989

Let M be a hypersurface of dimension n(.geq.2) in an (n+1)-dimensional real space form over bar M(c) with constant curvature c and H the second fundamental tensor of M. M is said to be birecurrent if here exists a covariant tensor field .alpha. of order 2 such that .del.$^{2}$H=H .alpha., where .del. is the connection of M. Also, M is said to be recurrent if there exists a 1-form .betha. such that .del.H=H .betha.. Matsuyama [2] recently proved that a recurrent hypersurface M in a real space form is locally symmetric and a complete irreducible birecurrent hypersurface M in a real space form is recurrent. The main purpose of this paper is to characterize the birecurrent or recurrent hypersurface M of a Riemannian manifold with constant curvature c and to prove that M is classified as a cylinder, $M^{n}$ (c) or ( $c_{1}$)* $M^{n-r}$ ( $c_{2}$) where 1/ $c_{1}$+1/ $c_{2}$=1/c.

• Journal of the Chungcheong Mathematical Society
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• v.5 no.1
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• pp.99-101
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• 1992

In this paper, we study some properties of sets of complete continuity. Moreover, we prove that if the subsets $C_1$ and $C_2$ of a Banach space X are sets of complete continuity, then so is the set $C_1{\times}C_2$ in the product space $X{\times}X$.

• Bulletin of the Korean Space Science Society
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• 1995.10a
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• pp.38-38
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• 1995

No Abstract, See Full Text

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.687-690
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• 2015

For research and development of Silicon Carbide (SiC) mirrors, the Korea Astronomy and Space Science Institute (KASI) and National Optical Astronomy Observatory (NOAO) have agreed to cooperate and share on polishing and measuring facilities, experience and human resources for two years (2014-2015). The main goals of the SiC mirror polishing are to achieve optical surface figures of less than 20 nm rms and optical surface roughness of less than 2 nm rms. In addition, Green Optics Co., Ltd (GO) has been interested in the SiC polishing and joined the partnership with KASI. KASI will be involved in the development of the SiC polishing and the optical surface measurement using three different kinds of SiC materials and manufacturing processes (POCO$^{TM}$, CoorsTek$^{TM}$ and SSG$^{TM}$ corporations) provided by NOAO. GO will polish the SiC substrate within requirements. Additionally, the requirements of the optical surface imperfections are given as: less than 40 um scratch and 500 um dig. In this paper, we introduce the international collaboration and interim results for SiC mirror polishing and development.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.420-428
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• 2019

This study is the heating energy saving test of the high-bed strawberry crown heating system. The system consists of electric hot water boiler, thermal storage tank, circulation pump, crown heating pipe(white low density polyethylene, diameter 16mm) and a temperature control panel. For crown heating, the hot water pipe was installed as close as possible to the crown part after planting the seedlings and the pipe position was fixed with a horticultural fixing pin. In the local heating type, hot water at $20{\sim}23^{\circ}C$ is stored in the themal tank by using an electric hot water boiler, and crown spot is partially heated at the setting temperature of $13{\sim}15^{\circ}C$ by turning on/off the circulation pump using a temperature sensor for controlling the hot water circulation pump which was installed at the very close to crown of strawberry. The treatment of test zone consisted of space heating $4^{\circ}C$ + crown heating(treatment 1), space heating $8^{\circ}C$(control), space heating $6^{\circ}C$ + crown heating(treatment 2). And strawberries were planted in the number of 980 for each treatment. The heating energy consumption was compared between November 8, 2017 and March 30, 2018. Accumulated power consumption is converted to integrated kerosene consumption. The converted kerosene consumption is 1,320L(100%) for space $8^{\circ}C$ heating, 928L(70.3%) for space $4^{\circ}C$ + crown heating, 1,161L($88^{\circ}C$) for space $6^{\circ}C$ + crown heating). It was analyzed that space $4^{\circ}C$ + pipe heating and space $6^{\circ}C$ + crown heating save heating energy of 29.7% and 12% respectively compared to $8^{\circ}C$ space heating(control).

• Bulletin of the Korean Space Science Society
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• 2000.04a
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• pp.54-54
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• 2000

No Abstract, See Full Text

• Bulletin of the Korean Space Science Society
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• 2000.10a
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• pp.82-82
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• 2000

No Abstract, See Full Text

• Publications of The Korean Astronomical Society
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• v.12 no.1
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• pp.99-109
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• 1997

We obtained the CN($\Delta_V=0$) and $C_2(\Delta_V=0,\;\pm1$) spectra of comet Hale-Bopp(C/1995 O1) at the Kyunghee Observatory and Bohyunsan Astronomical Observatory between March 7 and May 12, 1997 The fluxes for each molecular band were measured and then the production rates and column densities of CN and $C_2$ were calculated using a simple model. The resultantproduction rates of CN and $C_2$ are logQ(CN)=27.4 at r=0.94 AU(preperihelion) and $logQ(C_2)=27.3$ at r=0.94 AU(postperihelion), respectively.