• Journal of The Korean Astronomical Society
• /
• v.37 no.5
• /
• pp.447-454
• /
• 2004

During the hierarchical formation of large scale structure in the universe, the progressive collapse and merging of dark matter should inevitably drive shocks into the gas, with nonthermal particle acceleration as a natural consequence. Two topics in this regard are discussed, emphasizing what important things nonthermal phenomena may tell us about the structure formation (SF) process itself. 1. Inverse Compton gamma-rays from large scale SF shocks and non-gravitational effects, and the implications for probing the warm-hot intergalactic medium. We utilize a semi-analytic approach based on Monte Carlo merger trees that treats both merger and accretion shocks self-consistently. 2. Production of $^6Li$ by cosmic rays from SF shocks in the early Galaxy, and the implications for probing Galaxy formation and uncertain physics on sub-Galactic scales. Our new observations of metal-poor halo stars with the Subaru High Dispersion Spectrograph are highlighted.

• Journal of The Korean Astronomical Society
• /
• v.37 no.5
• /
• pp.483-491
• /
• 2004

Clusters of galaxies are storage rooms of cosmic rays. They confine the hadronic component of cosmic rays over cosmological time scales due to diffusion, and the electron component due to energy losses. Hadronic cosmic rays can be accelerated during the process of structure formation, because of the supersonic motion of gas in the potential wells created by dark matter. At the shock waves that result from this motion, charged particles can be energized through the first order Fermi process. After discussing the most important evidences for non-thermal phenomena in large scale structures, we describe in some detail the main issues related to the acceleration of particles at these shock waves, emphasizing the possible role of the dynamical backreaction of the accelerated particles on the plasmas involved.

• Journal of Plant Biology
• /
• v.15 no.2
• /
• pp.7-19
• /
• 1972

The studies of density effect or the effect of population density on plant growth have been done on basis of dry matter production with Raphanus acanthiformis var. simoodaeguen, Brassica campestris var. Pekinensis f. namsounsokoombecheu, Oryza sativa f. kimmajae and O. sativa f. mangyeng grown in the various spacing. 1. In the early period of plant growth in dry weight was not different each other among varying densities, but as time advanced the plant grown vast space grew sufficiently compared with those of narrow one. 2. Iogarithmic relation between the growth of plant (W) and the density (P), log W-log P in the material plants, were approximated by two straight lines, one was horizontal line and another inclined: the former showed non-competition density and the latter competition density addition to these the point interlinking both lines were implied of the optimum density per unit land area at certain growth period. 3. The values of relatvie growth rate (RGR) and net assimilation rate (NAR) were decreased as increase in the density, while those of leaf area ratio (LAR) were rather increased in the same condition, with minor exception. From these results and relation between the productive structure and due to lack of the recieved light intensity owing to the mutal shading among the plants.

• Journal of the Korean Home Economics Association
• /
• v.35 no.1
• /
• pp.257-262
• /
• 1997

In this thesis considering the problems shown in the usage of interlining of clothes and in the process of sewing the breaking away strength which is meant by adhesion is analysed by experimennt in which Polyamide content is dealed with at the 5 level to raise the adhesive strength by using the one-sided non woven adhesive interlining made in this country as the samples. After examing the optimum in the process of Cotton and polyester fabrics and adhered fabrics practical for blouse and jacket and analysing the breaking away strength the wanted property of matter and the change with the repeated laundry We reach at the following results. 1. The adhesive strength of the two adhered fabrics were strongly appeared in order of cotton>polyester. 2. The order of the breaking away strength by the interlinings of adhesive fabrics was A5> A4> A3> A2> A1. 3. The breaking away strength of the two adhered fabrics was weakened by the repeated laundry and the breaking away phenomena were fewer under the most suitable conditions than the various conditions.

• Journal of Advanced Marine Engineering and Technology
• /
• v.27 no.4
• /
• pp.467-478
• /
• 2003

Automotive shock absorber may not be regarded as only one(simple) damping machine because it is composed of many components, and shows non-linear damping characteristics. No matter how advanced form of shock absorber is developed, the oil shock absorber can not be neglected. because their structures are based on the oil shock absorber. Therefore it is essential to accurately analyze the dynamic characteristics of oil shock absorber. It stands mainly roi damper valve tuning which nowadays is still exhaustively done by means of ride work. In this study, damping mechanism and dynamic characteristics for oil shock absorber of twin tube type are analyzed, based on the mathematical model considering internal flow and pressure. For the reliability of numerical prediction. the database is constructed within the limit of adequate reliability. Finally, the programmed system that gives out necessary specification by inputting damping specification and tolerance is to be constructed.

• Tribology and Lubricants
• /
• v.23 no.3
• /
• pp.89-94
• /
• 2007

The stress and displacement behavior analysis of an aluminum tube for an organic photo conductor drum has been presented using a finite element analysis technique by non-linear FEM program. The maximum displacement in the radial direction of OPC drum may directly affect to the quality of printed matter. Thus, the deformed profile of the aluminum tubes should be limited depending on the toner powder size and the contact rolling forces between an OPC drum and a paper. This paper recommends the critical loading of 400 Pa for the provided toner size, $8{\mu}m$ for excellent printed matters and long life of the toner cartridge.

• Asian-Australasian Journal of Animal Sciences
• /
• v.7 no.4
• /
• pp.481-486
• /
• 1994

The effect of neutralization of urea-treated rice straw with sulfuric acid was investigated. Long-cut (15-20 cm) and short-cut (2-3 cm) rice straw were treated with 6% urea for 21 days, and the treated straw was mixed with an acid-molasses solution to neutralize free ammonia and kept airtightly in a plastic bag for 24 hours. The neutralized and non-neutralized straw were dried and subjected to chemical analysis and in vitro dry matter (DM) digestibility determination. The in vitro DM digestibility as well as crude protein (CP) content were remarkably improved by neutralization. Short-cutting of the straw before treatment gave a better result than the long-cut samples. Neutralization with sulfuric acid also affected the chemical composition and increased sulfur content of samples. The CP thus fixed by neutralization was proven to be kept stable for 3 months, and in vitro DM digestibility was not affected by the storing period.

• Journal of Astronomy and Space Sciences
• /
• v.25 no.4
• /
• pp.329-334
• /
• 2008

We investigate the spectral energy distributions (SEDs) of Massive Young Stellar Objects (MYSOs) using the various infrared observational data including the Infrared Space Observatory (ISO) data. We model the dust envelopes around the stars using a radiative transfer model for spherically symmetric geometry. Comparing the model results with the observed SEDs of the two MYSOs (AFGL 4176 and AFGL 2591), we derive the relevant dust shell parameters including the dust opacity, the dust density distribution, and dust temperature distribution. We find that the spherical model can produce the SEDs roughly similar to the observations. We expect that the results would be helpful for making more realistic non-spherical dust envelope models for MYSOs.

• Journal of the Korean Institute of Educational Facilities
• /
• v.2 no.1
• /
• pp.15-26
• /
• 1995

This paper discussed non-physical factors, such as the level of use of organizational channels and the level of R&D investment of the firm. It also explored physical factors such as the distance between the university and industry, transportation conditions between the two, and the availability (surplus capacity) of professors' or firms' research facilities that would affect the interaction such as the contacts in connection with research grants and consultations by professors to high-tech firms. This paper pointed out that the use of organization channel, the level of R&D investment, the availability research facilities of the university and high-tech firm, transportation conditions between the two, subject matter compatibility between professors' areas of expertise and firms' industrial activities, professors' (or staff) research capabilities and professors' (or staff) research times affect the interaction between the university and industry. It also found that the distance between the university and industry affects the interaction between the two in the opposite direction.

• 보존과학연구
• /
• s.21
• /
• pp.273-291
• /
• 2000

The perilla oil is painted to the wooden cultural properties of protection of wood and pigment. But that is happened to discolor and gather mold because of the long drying time. So we were put to the test for the improvement of this matter. The result is follows;1. The perilla oil, do not parched domestic Perilla japonica, add to the Japanese acid clay, later passing through the filter paper that the pore size is less than $7\mum$ 2. If the perilla oil add to the antiseptic of Thiazole origin, the mold is suppressed.3. In the painting of perilla oil, the existing Dan-chung paints one time (Luster generation in the more than two times) and the non-existing Dan-Chung paints two times.