• 수산해양기술연구
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• 제16권2호
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• pp.85-85
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• 1980

• Applied Microscopy
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• 제46권1호
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• pp.27-31
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• 2016

It has been investigated what kind of characteristic X-ray in electron probe micro-analyzer (EPMA) is effective for the determination of compounds of Si series materials. After comparing the characteristic X-rays among the primary and secondary lines in $K_{\alpha}$ and $K_{\beta}$ obtained from the Si series standard samples, it was found that the secondary line of $K_{\alpha}$ exhibited the most informative spectrum although the intensity was considerably weak. As a result of analyzing the spectrum shapes of the Si series standard samples, the spectrum shape of the secondary line of $K_{\alpha}$ for SiC was different from those for other Si compounds. To grasp the characteristics of the shape, a line was perpendicularly drawn from the peak top to base line in order to divide a spectrum into two areas. The area ratio of right to left was defined to call as the asymmetry index here. As a result, the asymmetry index value of the SiC was greater than one, while those of other Si compounds were less than one. It was found from the EPMA analysis that identification of SiC became successful to distinguish from other Si compounds and this method was applicable for micro-sized compounds in a practical composite material.

• 한국생산제조학회지
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• 제20권1호
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• pp.40-46
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• 2011

This paper is to investigate the effects of the asymmetrical support stiffness on the stability of a supercritical driveshaft with asymmetrical shaft stiffness and anisotropic bearings. The equations of motion is derived for a system including a rigid disk, a massless flexible asymmetric shaft, anisotropic bearings and a support beam. The Floquet theory is applied to perform the stability analysis with the variation of the support stiffness, the shaft asymmetry, the shaft damping and the shaft speed. The results show that the asymmetric support stiffness is closely related to the stability caused by primary resonance as well as the supercritical operation. First, the stiffness variation can stabilize the system around primary resonance by weakening the parametric resonance from the shaft asymmetry. Second, it also improve the stability characteristics at a supercritical operation when the support stiffness is not so high relative to the shaft stiffness.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.429-431
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• 2009

Drawability and other mechanical properties of sheet metals are strongly dependent on their crystallographic orientations. In this paper the formability of the AA 5052 Al alloy sheets was investigated after asymmetric rolling and subsequent heat treatment. In most cases, after asymmetric rolling specimens showed a fine grain size and subsequent heat treated specimens showed that the ND // <111> texture component were observed. The anisotropy of formability is often described by the plastic strain ratios (r-value) as a function of the angle to the rolling direction in sheet metal. For a good formability, a high r-value is required in sheet metals. In the asymmetry rolled and subsequent heat treated Al alloy sheet, the variation of the plastic strain ratios have been investigated in this study, The plastic strain ratios of the asymmetry rolled and subsequent heat treated AA 5052 Al alloy sheets were higher than those of the original Al sheets. These could be related to the formation of ND // <111> texture components through asymmetric rolling in Al sheet.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.477-479
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• 2008

Drawability and other mechanical properties of sheet metals are strongly dependent on their crystallographic orientations. In this paper the formability of the AA 5052 Al alloy sheets was investigated after asymmetric rolling and subsequent heat treatment. In most cases, after asymmetric rolling specimens showed a fine grain size and subsequent heat treated specimens showed that the ND//<111> texture component were observed. The anisotropy of formability is often described by the plastic strain ratios (r-value) as a function of the angle to the rolling direction in sheet metal. For a good formability, a high r-value is required in sheet metals. In the asymmetry rolled and subsequent heat treated Al alloy sheet, the variation of the plastic strain ratios have been investigated in this study. The plastic strain ratios of the asymmetry rolled and subsequent heat treated AA 5052 Al alloy sheets were higher than those of the original Al sheets. These could be related to the formation of ND//<111> texture components through asymmetric rolling in Al sheet.

• 한국발생생물학회지:발생과생식
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• 제22권3호
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• pp.275-281
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• 2018

The purpose of this study is to examine fluctuating asymmetry of eye diameter, maxilla length, operculum length, and the number of pectoral fin ray and pelvic fin ray between ploidy and sex in diploid and triploid marine medaka, Oryzias dancena. In all experimental groups, eye diameter and maxilla length showed no significant difference between left side and right side (p>0.05). Results of operculum length in triploid male group and pectoral fin ray's number in diploid male group showed similarity ones with results of operculum length in triploid female group and pectoral fin ray's number in diploid female group (p<0.05). However, the operculum length in diploid male group and pectoral fin ray's number in triploid male group showed consinderable difference with those of operculum length in diploid female group and pectoral fin in triploid female group. Findings of pelvic fin ray's number in all groups were similar to those of pectoral fin ray's number in all groups (p<0.01).

• Earthquakes and Structures
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• 제6권5호
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• pp.473-494
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• 2014

Progressive collapse, which is referred to as the collapse of the entire building under local damages, is a common failure mode happened by earthquakes. The collapse process highly depends on the whole structural system. Since, asymmetry of the building plan leads to the local damage concentration; it may intensify the progressive collapse mechanism of asymmetric buildings. In this research the progressive collapse of regular and irregular 6-story RC ordinary moment resisting frame buildings are studied in the presence of the earthquake loads. Collapse process and collapse propagation are investigated using nonlinear time history analyses (NLTHA) in buildings with 5%, 15% and 25% mass asymmetry with respect to the number of collapsed hinges and story drifts criteria. Results show that increasing the value of mass eccentricity makes the asymmetric buildings become unstable earlier and in the early stages with lower number of the collapsed hinges. So, with increasing the mass eccentricity in building, instability and collapse of the entire building occurs earlier, with lower potential of the progressive collapse. It is also demonstrated that with increasing the mass asymmetry the decreasing trend of the number of collapsed beam and column hinges is approximately similar to the decreasing trend in the average story drifts of the mass centers and stiff edges. So, as an alternative to a much difficult-to-calculate local response parameter of the number of collapsed hinges, the story drift, as a global response parameter, measures the potential of progressive collapse more easily.

• 융합경영연구
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• 제7권2호
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• pp.1-5
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• 2019

Purpose - Along with the rise of foreign investments in the Korean stock market, there has been a variety of studies on their influence. The conflicting findings on the question of information asymmetry of foreign investors among existing literatures appear to be a result of mixture of research method problems, what information is defined as being comparable, individual business levels, or the entire stock market. This paper empirically investigates what factors contribute to foreign investments in firms in the Korean stock market. Research design, data, and Methodology - Samples are constructed by manufacturing firms listed on the stock market of Korea as well as those who settle accounts in December from 2001 to 2018. Financial institutions are excluded from the sample as their accounting procedures, governance and regulations differ. This study adopted the panel regression model to assess the sample construction including yearly and cross-sectional data. Result - This paper find that firms' R&D, dividends, size give significant positive impact to foreign investment, whereas debt gives significant negative impact to foreign investment. This relationship does not change when the samples are divided before and after the 2008 global financial crisis. Conclusion - This results support the literatures that foreign investors favor firms lowering their information asymmetry.

• 융합정보논문지
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• 제10권11호
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• pp.302-312
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• 2020

본 연구는 국내 상장시장 간 원가의 비대칭성의 차이가 있는지, 상장기업의 기업 규모에 따라 원가의 비대칭성이 차이가 있는지 검증하였다. 기존의 연구에서는 상장기업만을 대상으로 한 원가의 비대칭성은 살펴보았지만, 상장기업 간의 규모의 차이는 살펴보지 않았다. 그러나 다수의 연구에 따르면 상장시장 간 또는 상장기업이라 할지라도 기업의 특성이나 기업고유의 위험(firm risk)이 서로 다르기 때문에 이와 같은 영향이 기업 내부 자원배분 의사결정에 미치는 영향에 차이가 있을 것이라고 보고 분석을 실시하였다. 이를 위해 2011년부터 2019년까지 유가증권시장과 코스닥시장을 대상으로 Anderson et al.(2003)의 원가행태 모형을 이용하여 분석한 결과, 유가증권시장과 코스닥시장의 원가행태는 차이가 있는 것으로 나타났다. 전반적으로 선행연구와 마찬가지로 원가의 하방경직성이 보고되었으나 유가증권시장의 경우 원가의 하방경직성이 완화됨을 확인할 수 있었다. 기업규모가 클수록 매출액이 감소할 때 유휴자원의 처분의사결정이 더 뚜렷한 것으로 나타났다. 추가적으로 외국인투자자 지분율이 높은 경우, 유가증권시장일수록, 기업규모가 클수록 원가의 하방경직성의 완화는 더 크게 나타남을 관찰할 수 있었다. 본 연구는 원가의 비대칭성에 관한 연구를 확장하고 상장시장 간, 기업규모 간의 차이가 존재함을 밝힌 연구로써 선행 연구와의 차별성을 갖는다.

• 자원ㆍ환경경제연구
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• 제22권4호
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• pp.643-670
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• 2013

본 연구에서는 국제 원유가격의 변동에 따른 휘발유 가격의 조정 과정에 원유 재고량이 미치는 영향을 오차수정모형을 통해 분석하였다. 분석에는 미국시장의 자료를 이용하였으며, 분석기간은 1988년 1월부터 2012년 12월까지이며 전체기간에 대한 분석과 더불어 5년 단위로 구간을 나누어 구간별 비대칭성의 여부와 정도의 변화에 대해 원유 재고가 미치는 영향을 분석하였다. 분석 결과, 전체 기간에서는 재고변수 도입 여부와 관계없이 모두 대칭성이 나타났으나 구간별로는 공적분 관계를 가지는 경우에 한하여 원유와 재고 간 유의한 관계가 성립하였다. 또한 구간별로 비대칭적 조정이 다르게 나타났으며, 재고 변수 도입 여부에 의해 비대칭성의 정도가 다름도 확인하였다. 본 연구의 분석결과는 향후 비대칭성 연구에 있어서 재고 변수를 고려하여 구간별 유가의 변동성을 분석할 필요가 있음을 보여준다.