• The Journal of the Petrological Society of Korea
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• v.6 no.2
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• pp.133-149
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• 1997

In the metapelites around the Ogcheon granite, the metamorphic grade increases from the biotite zone through the andalusite zone to the sillimanite zone towards the intrusion contact. In the metabasites around the Boeun granite, the metamorphic grade increases from transitional zone between the greenchist and amphibolite facies through the amphibolite facies to the upper amphibolite facies towards the intrusion contact. In the Doiri area locating near the intrusion contact of the Boeun granite, sillimanite- and andalusite-bearing metapelites are found with in 500 m away from the contact. The evidence described above indicates that the Ogcheon and Boeun granites caused low-P/T type contact metamorphism to the country rocks. The P-T condition of contact metamorphism due to the intrusion of the Ogcheon granite is $540{\pm}40^{circ}C, 2.8{\pm}0.9$ kb. The temperature condition of contact metamorphism due to the intrusion of the Boeun granite is $698{\pm}28^{\circ}C$. The wide compositional range of amphibole and plagioclase in the metabasites around the Boeun granite is due to the immisibility gab of amphibole and plagioclase and unstable relict composition resulted from an incomplete metamorphic reaction. The compositional range of stable amphibole and plagioclase decreases as a metamorphic grade increases due to a close of immiscibility gab. The thermal effect of contact metamorphism due to the intrusion of the Ogcheon and Boeun granites, are calculated using the CONTACT2 program based on a two dimensional finite difference method. In order to estimate the thermal effect of an introduced pluton, a circle with 10 km diameter and a triangle with 20 km side are used for the intrusion geometries of the Ogcheon granite and the Boeun granite, respectively. The results from the field and modeling studies suggest that the intrusion temperatures of the Ogcheon granite close to $800^{\circ}C$ and the intrusion temperature of the Boeun granite is higher than $1000^{\circ}C$. However, the intrusion temperatures can be lower than the suggested temperature, if the geothermal gradient prior to the intrusion of the Ogcheon and Boeun granites was higher than the normal continental grothermal gradient.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.577-580
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• 2003

Stress state of chip formation zone is one of the main problems in metal cutting mechanics. In two-dimensional case this process is usually considered as consistent shears of work material along single of several shear surfaces. separating chip from workpiece. These shear planes are assumed to be trajectories of maximum shear stress forming corresponding slip-line field. This paper suggests new approach to the constriction of slip-line field, which Implies uniform compression in chip formation zone. On the base of given model it has been found that imaginary shear line in orthogonal cutting is close to the trajectory of maximum normal stress and the problem about its determination have been considered. It has been shown that there is a second central slip-line field inside chip, which corresponds well to experimental data about stress distribution on tool rake face and tool-chip contact length. The suggested model could be useful in solution of various problems of machining.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.368-373
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• 1996

A simple set of the transition criterion of the condensation regimes and the heat transfer coefficients on the direct contact condensation of the core makeup tank is developed, and implemented in RELAP5/MOD3.1 The condensation regimes are divided into two regimes: supply limit and condensation limit. In mode]ing the transition criterion between two regimes, a large-eddy model developed by Theofanous is used, and the empirical coefficient of the present large-eddy model is close to that of the large-eddy model. It turns out that the modified code better predicts the experimental data, especially the injection flow rate and the water level trend than the original code does.

• Journal of Plant Biology
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• v.5 no.2
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• pp.1-5
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• 1962

Attempts were made in order to make clear the meiotic irregularities, male gametophyte formation and spermatogenesis for the purpose of applying these embryological facts to taxonomic works. Followings are the results obtained : 1. Meiosis is extremely irregular, giving rise to giant, micro, and empty, pollens. Meiotic division in each PMC is observed synchronizing. 2. In the microspore immediately before the vegetative-generative nuclear division, the nucleus locates appressed to the inner wall, most of the other part of the cell being occupied by large vacuoles. 3. Spindle symmetry in the microspore nuclear division is of intermediate type. 4. Nuclear divisions in each micropore are not synchronized as in meiosis. 5. Generative nucleus is located in close contact with the inner wall, while the vegetative nucleus occupies the central part of pollen grain. The pollen in this stage looks somewhat like broad bean. Afterward the generative nucleus loses contact with the wall, the nuclear shape changing from lenticular to roundsh. 6. The generative nucleus in fully matured pollen grain usually takes the shape of crescence, those in abortive pollen, lenticular or ellipsoidal, etc.

• The Korean Journal of Zoology
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• v.39 no.2
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• pp.223-230
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• 1996

Fine structure of the neuromuscular junction in the venomous organ of the spider, Agelena li'mbutq, was studied using high magnification electron microscope. The motor nerve endings at neuromuscular contact area composed of neurons and neuroslial cells were located between musculature and extracellular sheath of the venom gBand. At the synaptic contact between a motor axon and a muscle fiber in the musculature, spherical synaptic vesicles were prominent in the nerve terminal. The sarcoplasm beneath the neuromuscular synapse has a granular appearance and lacks mvofilaments. And the main axon gives off a branch between the muscle fibers. The synaptic regions of this organ are located close to the myofilaments unlike to other chelicerate classes. Moreover the postsvnaptic complex of vesicles and membrane invasinations present in other synaptic legions are absent from these legions in this venomous organ.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.318-331
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• 2000

Electrical and tribological behaviours of a copper-graphite brush in a slipring-brush assembly were investigated to evaluate the characteristics of electric signal transmission between a slipring and a brush. Five brush materials containing different amounts of copper and graphite were studied. The result showed that a copper-graphite brush at a particular graphite content exhibited the most stable frictional and electrical behaviour suggesting an optimum amount of a solid lubricant in a metal-graphite brush system. Microscopic observation and the surface analysis showed good agreements with this phenomena. In addition, the deviation of the friction coefficient and electric signal distortion has a close relationship with a microscopic mechanical vibration and the change of a real contact area.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.60-60
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• 2018

It has been known that XZ CMi is a near-contact binary composed of a hotter and more massive main-sequence primary star close to its Roche-lobe and a Roche-lobe filling giant/subgiant secondary star. There still exist, however, many discordant matters among the previous investigators: diverse mass ratios and temperatures ranging from 0.38 to 0.83 and from 7,000 K to 8,876 K, respectively. In order to make a contribution to the two confusions we conducted spectroscopic and photometric observations. A total of 34 high-resolution spectra were obtained during 4 nights from 2010 and 2018 with the Bohyunsan Optical Echelle Spectrograph (BOES) at the Bohyunsan Optical Astronomy Observatory (BOAO). In parallel, BVRI multi-band photometric observations were carried out 5 nights in 2010 at Sobaeksan Optical Astronomy Observatory (SOAO). In this presentation, we present physical parameters of XZ CMi through the simultaneous analyses of new double-lined radial velocity curves and new light curves. We will also briefly discuss the evolutionary status of the system.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1786-1790
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• 2004

The main objective of this paper is to analyze the performance of various force control algorithms in improving and adjusting the compliance of industrial robots in contact with their environment. Some of fundamental force control algorithms such as sensorless control, impedance control and hybrid position/force control are theoretically analyzed and simulated for various situations of an environment, and then a series of experiments using them were performed. In this paper, a control scheme to use position control in implementing the impedance control was investigated in order to nullify the effect of joint friction. The new reference trajectory is generated using contact force feedback and original desired trajectory. And an inner position control loop is designed to provide accurate position tracking for the new reference trajectory and good disturbance rejection. Experiments to insert a peg in a hole (so-called the peg-in-a-hole task) were performed with HILS (hardware-in-theloop simulation) system based on the results of the analyses and simulations on the characteristics of each control algorithm. The experiments showed that various force control methods improved the performance of robots in close contact with the environment by adjusting their compliance with respect to an arbitrary set of coordinates.

• Journal of The Korean Astronomical Society
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• v.49 no.3
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• pp.65-71
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• 2016

We obtain the first complete CCD light curves (LCs) of the contact binary AP UMi in the VRI bands and analyzed them by means of the PHOEBE code. A spotted model is applied to treat the asymmetry in the LCs. The LC morphology clearly shows the O'Connell effect and the solution shows an influence of star spots on both components. Such effect of star spots is common between the RS CVn and W UMa chromospherically active stars. Based on the obtained solution of the LCs we investigate the evolutionary state of the components and conclude that the system is a pre-intermediate contact binary (f = 0.29) with mass ratio q = 0.38, and it is an A-type W UMa system where the less massive secondary component is cooler than the more massive primary one.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.541-545
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• 2009

This study evaluated the contact resistance, insulation resistance, withstand voltage characteristics and insertion force, etc., of the wire connector used inside an integrated LITE WAY lighting fixture developed for efficient installation. Since the connector connecting the lighting fixture's internal wires is housed, it is easily connected and separated and has a structure enabling a close-fitting connection. The temperature and time applied to the high temperature characteristics test of the connector are $105^{\circ}C$ and 16 hours, respectively. The measured contact resistance of the high temperature tested connector was 3.258 mV/A, and its measured insulation resistance was greater than $10\;G{\Omega}$ All specimens demonstrated uniform insulation characteristics, which could be seen to be in good condition. From the withstand voltage test results found before and after performing the high temperature operation test on the connector for cable connection, it was confirmed that the withstand voltage characteristics between all terminals were good. The insertion force of the connector connecting the internal wiring averaged 9.67 kgf. It was observed that the insertion force between the plug housing and the female terminal, and that between the plug housing and the male terminal, were 0.680 kgf and 1.27 kgf on average, respectively.