• Korean Journal of Mineralogy and Petrology
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• v.34 no.1
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• pp.41-56
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• 2021

The characteristics of the six rock cleavages(R1~H2) in Jurassic Hapcheon granite were analyzed using the distribution of ① microcrack lengths(N=230), ② microcrack spacings(N=150) and ③ Brazilian tensile strengths(N=30). The 18 cumulative graphs for these three factors measured in the directions parallel to the six rock cleavages were mutually contrasted. The main results of the analysis are summarized as follows. First, the frequency ratio(%) of Brazilian tensile strength values(kg/㎠) divided into nine class intervals increases in the order of 60~70(3.3) < 140~150(6.7) < 100~110·110~120(10.0) < 90~100(13.3) < 80~90(16.7) < 120~130·130~140(20.0). The distribution curve of strength according to the frequency of each class interval shows a bimodal distribution. Second, the graphs for the length, spacing and tensile strength were arranged in the order of H2 < H1 < G2 < G1 < R2 < R1. Exponent difference(λS-λL, Δλ) between the two graphs for the spacing and length increases in the order of H2(-1.59) < H1(-0.02) < G2(0.25) < G1(0.63) < R2(1.59) < R1(1.96)(2 < 1). From the related chart, the six graphs for the tensile strength move gradually to the left direction with the increase of the above exponent difference. The negative slope(a) of the graphs for the tensile strength, suggesting a degree of uniformity of the texture, increases in the order of H((H1+H2)/2, 0.116) < G((G1+G2)/2, 0.125) < R((R1+R2)/2, 0.191). Third, the order of arrangement between the two graphs for the two directions that make up each rock cleavage(R1·R2(R), G1·G2(G), H1·H2(H)) were compared. The order of arrangement of the two graphs for the length and spacing is reverse order with each other. The two graphs for the spacing and tensile strength is mutually consistent in the order of arrangement. The exponent differences(ΔλL and ΔλS) for the length and spacing increase in the order of rift(R, -0.08) < grain(G, 0.14) < hardway(H, 0.75) and hardway(H, 0.16) < grain(G, 0.23) < rift(R, 0.45), respectively. Fourth, the general chart for the six graphs showing the distribution characteristics of the microcrack lengths, microcrack spacings and Brazilian tensile strengths were made. According to the range of length, the six graphs show orders of G2 < H2 < H1 < R2 < G1 < R1(< 7 mm) and G2 < H1 < H2 < R2 < G1 < R1(≦2.38 mm). The six graphs for the spacing intersect each other by forming a bottleneck near the point corresponding to the cumulative frequency of 12 and the spacing of 0.53 mm. Fifth, the six values of each parameter representing the six rock cleavages were arranged in the order of increasing and decreasing. Among the 8 parameters related to the length, the total length(Lt) and the graph(≦2.38 mm) are mutually congruent in order of arrangement. Among the 7 parameters related to the spacing, the frequency of spacing(N), the mean spacing(Sm) and the graph (≦5 mm) are mutually consistent in order of arrangement. In terms of order of arrangement, the values of the above three parameters for the spacing are consistent with the maximum tensile strengths belonging to group E. As shown in Table 8, the order of arrangement of these parameter values is useful for prior recognition of the six rock cleavages and the three quarrying planes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.5
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• pp.82-89
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• 2014

In this paper, fire resistance test was carried out to obtain class H-120 thermal insulation of fire dampers according to a hydrocarbon fire conditions. Specimens were fabricated three different types according to the change of the insulation system applied to damper blade and coaming which were measured surface temperature by performing the fire resistance test. As a test result, specimen-1, 2 of an uninsulated damper blade were exceeded thermal insulation acceptance criteria at 21 minutes, 46 minutes respectively, but specimen-3 of an insulated damper blade was satisfied thermal insulation acceptance criteria during 120 minutes. The test results showed that the insulation of the damper blade was an important factor in the fireproof performance of fire dampers concerning the coaming length minimum 500 mm on the unexposed side as specified test standard.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.39.2-40
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• 2016

The molecular gas surrounding an H II region is thought to be a place where star formation can be induced. Such triggered star formation can arise form the overpressurization of existing density enhancements or thought the collapse of a swept up layers of material. In this talk, We will discuss the results of a study of star-formation activity associated with the outer Galaxy ring-shaped H II regions KR 7, KR 81, KR 120 and KR 140 using archival Spitzer and WISE data along with the JHK observations. We used CO data cubes from the FCRAO and TRAO in order to define extent of the molecular cloud associated each HII region. Using the infrared data sets, We identified and classified YSO populations within each molecular cloud using measures such as the class I/II ratio and YSO spatial density. Along with this, one of the main question in the study of star formation is how protostar accrete material from their parent molecular clouds and observations of infall motions are needed to provide direct evidence for accretion. Combining our observation of the YSO population distribution with time scales associated with YSO evolution and HII expansion, we investigated the possible significance of triggered star formation in the molecular cloud surrounding each region.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.119-120
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• 2014

멀티레벨 인버터는 낮은 고조파 성분을 갖고, 제한된 정격 스위칭 소자로 대용량 전력변환이 요구되는 시스템에 매우 효율적이다. 수학적인 해석방법을 통해 전도손실, 스위칭 손실, 출력 전압 전류의 THD의 해석방법을 제시하고 시뮬레이션을 통해 멀티레벨 인버터의 특성을 비교 분석을 한다. 본 논문은 기존 제안된 멀티레벨 구조인 NPC(Neutral Point Clamped) 멀티레벨 인버터, Cascaded H-bridge 멀티레벨 인버터, Flying capacitor 멀티레벨인버터를 기반으로 25MW급 대용량 인버터의 손실 및 출력특성을 비교 분석하였다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.11
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• pp.1602-1607
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• 2014

This paper deals with the design and property analysis of 7kW-class small-scaled superconducting Linear Synchronous Motor (LSM) and testing equipment for a number of performance pre-tests prior to the development of coreless-type superconducting LSM suitable for 600km/h very high speed train. First, the basic design and property analysis are conducted before developing a small-scaled superconducting LSM model with 2-pole superconducting electromagnets, and additionally the cost-down design of the superconducting electromagnets is conducted to use less high-Tc superconducting wire. Finally, the superconducting magnet coil span is selected at 120mm, and input ground armature current of 670Aturns is required to produce 44.7N of thrust based on research findings.

• Bulletin of the Korean Chemical Society
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• v.28 no.3
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• pp.379-385
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• 2007

Receptor-oriented pharmacophore-based in silico screening is a powerful tool for rapidly screening large number of compounds for interactions with a given protein. Inhibition of the enzyme catechol-Omethyltransferase (COMT) offers a novel possibility for treating Parkinson's disease. Bisubstrate inhibitors of COMT containing the adenine of S-adenosylmethionine (SAM) and a catechol moiety are a new class of potent and selective inhibitor. In the present study, we used receptor-oriented pharmacophore-based in silico screening to examine the interactions between the active site of human COMT and bisubstrate inhibitors. We generated 20 pharmacophore maps, of which 4 maps reproduced the docking model of hCOMT and a bisubstrate inhibitor. Only one of these four, pharmacophore map I, effectively described the common features of a series of bisubstrate inhibitors. Pharmacophore map I consisted of one hydrogen bond acceptor (to Mg2+), three hydrogen bond donors (to Glu199, Glu90, and Gln120), and one hydrophobic feature (an active site region surrounded by several aromatic and hydrophobic residues). This map represented the most essential pharmacophore for explaining interactions between hCOMT and a bisubstrate inhibitor. These results revealed a pharmacophore that should help in the development of new drugs for treating Parkinson's disease.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.236.1-236.1
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• 2012

We conducted simultaneous 22GHz water maser and 44GHz class I methanol maser surveys of newly-identified 282 H2 emission features from the $2.122{\mu}m$ H2 narrowband image survey in the Galactic plane (UWISH2 project) using Korea VLBI Network (KVN) 21-m radio telescopes. We detected 16 and 13 new water and methanol maser sources, respectively. This result indicates that at least ~5% of the H2 emission features originate from young stellar objects (YSOs) that are in the right physical condition to produce the water and methanol masers. The masers are closely related to the current outflow activities in the Galactic plane. The power sources of these 23 diffused/collimated H2 emission features (six sources are detected for both masers) are likely to be intermediate-to high-mass YSOs, based on a comparison with the maser luminosities of other well-studied YSOs. Both maser velocities are mostly close to their own systemic velocities within 5 km/s, even though water masers generally show larger variabilities in the line intensities, velocities, and shapes than methanol masers. We also discovered three new water maser sources with high-velocity components: ~25 km/s red-shifted CMHO019, ~50 km/s blue-shifted CMHO132, and ~120 km/s blue-shifted CMHO182. In particular, we propose that the dominant blue-shifted water maser of CHMO182 could become a unique laboratory for the study of high-mass stellar jet and their accelerations.

• The korean journal of orthodontics
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• v.32 no.4 s.93
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• pp.241-255
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• 2002

This study was performed to evaluate horizontal and vertical characteristics according to lateral cephalometry of adult Korean skeletal Class II patients using a selected horizontal and vortical reference planes of Koreans. 60 males and 60 females consisting of freshman of Yonsei University from 1996 to 1997 and patients with history of orthognatic surgery at the Dental Hospital of Yonsei University with a skeletal Class II profile were chosen and compared with 70 males and 70 females with normal occlusion. The skeletal Class R group had the following conditions : 1. Profile composed of a retrognathic mandible or protrusive maxilla; 2. Class II molar and canine key; 3. ANB-greater than $4^{\circ}; 4$. Wits appraisal-greater than 1.0mm; Cephalometric analysis consisted of 22 skeletal, 25 soft tissue, 12 dental measurements. The results were as follows. 1. There was no considerable vortical measurement difference between the skeletal Class II malocclusion group and the normal occlusion group in skeletal analysis. But, some variations were found between the two groups in soft tissue analysis. 2. Mandibular length of the skeletal Class II malocclusion group was smaller than that of the normal occlusion group. Mandible was more posteriorly positioned in the Class II malocclusion group than in the normal occlusion group. 3. The length and antero-posterior position of the maxilla were not different between the Class II malocclusion and the normal occlusion group. 4. The antero-posterior position of the nose, upper lip and maxillary soft tissue, and nasolabial angle were not different between the two groups. 5. Mandibular soft tissue of the Class H malocclusion group was more posteriorly positioned than that of the normal. 6. The vertical measurements of the incisors(U1-HP, L1-HP) were bigger in the Class II malocclusion group than in the normal, but those of the molars(U6-HP, U6-MP) showed no significant difference between the two groups. 7 Classifying the skeletal Class II malocclusion group according to the antero-posterior position of both jaws, normally positioned maxilla and retruded mandible was 43.3%, both normally positioned maxilla and mandible 28.3%, both retruded maxilla and mandible 20.0%..

• Journal of Elementary Mathematics Education in Korea
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• v.5 no.1
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• pp.99-120
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• 2001

The purpose of this thesis is to find the guiding direction of mathematical communication in lower grade students of elementary school and to present a new direction about the effect of using concrete material in communication. It is expected that mathematical communication increases when concrete material is used for the students of the lower grades, who are in concrete operational period. Therefore, this study ai s to investigate what characteristics there are in mathematical communication of second grade students and what effect concrete materials have on mathematical communication and learning. The analysis of the teaching record shows that the second grade students use alternative terms in the process of communication since they are not familiar with mathematical symbols or terms, which is a characteristic of communication in a mathematics class in which concrete material is used. In the process of teaming the students apply their living experiences to their teaming. Since a small number of students lead class, the interaction between students is also led by them. The direction of communication in a small group is not centered around solution of a problem, and most students show a more interest in finding answers than in the process of learning. The effect that concrete material has on communication plays an important role in promoting students' speaking activity; it allows students to identify and correct their errors more easily. It also makes students' activities more predictable, and it increases a small group activities through the medium of concrete material. However, it was also noticed that students' listening activities are not appropriately developed since they do not pay attention to a teacher who uses concrete material. The effects that concrete material has on mathematics class can be summarized as follows. Concrete material promotes students' participation in class by triggering their interest of learning of mathematics and helps them to understand the course of learning. It also helps the teaming and formation of concepts for children of low academic performance. And it makes a phased learning possible according to students' ability to use concrete material and to solve a problem. Based upon the results above mentioned, the use of concrete material is absolutely needed in mathematics classes of lower grade elementary school students since it increases communication and gives much influence on mathematics learning. Therefore, teachers need to develop teaching or learning method which can help increase communication, considering the characteristics of students' communication.

• Korean Journal of Environment and Ecology
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• v.8 no.2
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• pp.107-120
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• 1995

To investigate the forest structure of Chuwang valley of Chuwangsan National Park, thirty plots were set up and surveyed. Importance values, DBH class distribution, species diversity indices, DCA Ordination, CCA ordiantion and TWINSPAN classification were used for vegetational structure analysis. Pinus densiflora Quercus serata, Q. mongolica, Q. variabilis were appeared to be dominant species in thirty plots. According to the analysis of classification by TWINSPAN, the thirty plots divided four groups. Groups were Q. mongolica-P. densiflora-Carpinus laxiflora community(I), P. densiflora-Q. variabilis community(II), Q. serrata-Q. variabilis community(III), broad-leaved mixed community(IV) Species diversity(H') of investigated area was calculated 1.17~l.32. The successional trend was seemed to be from P. densiflora to Q. spp. in the canopy layer.