• 한국지반공학회지:지반
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• 제3권2호
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• pp.7-16
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• 1987

흙의 동적 특성은 공극비, 구속압력, 입도 등의 여러가지 요인에 의해서 변화한다. 본 연구에서는 모래의 입도가 그 동적 특성에 미치는 영향을 구속압력과 공극비의 영향과 함께 실험적으로 살펴 보았다. 실험 결과, 전단탄성계수(Shear Modulus)와 감쇠비 (Damping Ratio)는 공극비가 감소 함에 따라, 그리고 구속압력이 증가함에 따라 각카 증가 및 감소하였다. 한펀, 실트 크기의 석영분말을 섞어 입도를 변화시켰을 때, 시료의 전단탄성계수와 감쇠비는 석영 분말의 함유량이 증가함에 따라 각각 감소 및 증가하였다. 여기서는 이 현상을 "유효 접촉수"와 "사공간"의 개념을 써서 미시적으로 살펴보았다. 개념을 써서 미시적으로 살펴보았다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.511-518
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• 2000

Characteristics of joint orientation, length, spacing and their distribution are very important factors for slope stability, Especially, the effect of joint spacing is an essential factor of slope stability. This study is to analyze the effect of joint spacing in cases of sliding and toppling, which is a typical failure mode. Joint spacing can divided into vertical spacing(spacing) and horizontal spacing(gap). And then, the spacing/length ratio of joint directly affect rock slope failure. When the ratio is below 0.05, the possibility of failure is rapidly increased. In case of toppling, the possibility of failure depends on the ratio of spacing to height of slope ratio slope. As the ratio decreases, the possibility of toppling failure increased. The critical ratio of spacing to height of slope is determined by the dip angle of the slope and the orientation of joint sets.

• 한국기계가공학회지
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• 제8권4호
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• pp.90-96
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• 2009

The loading condition of actual construction works is complex. The shear effect of mixed-mode load component are crack propagation mechanism in step larger than the crack initial mechanism. Therefore, in this study received a mixed-mode loading on fatigue crack stress ratio on crack propagation path and speed of progress to learn whether stress affects crack propagation. ${\Delta}$ P a constant state of fatigue tests in Mode I, II give the same stress ratio, frequency 10Hz, sinusoidal waveform was used. A lower stress ratio fatigue crack propagation angle is small. This is less affected by the Mode II. Therefore, a mixed-mode fatigue crack propagation is to progress by the Mode. Stress ratio in a mixed mode crack in the path of progress and found a lot of impact.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1988년도 춘계학술대회 논문집
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• pp.46-48
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• 1988

The effect of cold reduction ratio on magnetic properties of 45% Ni-Fe permalloy was studied. To know the relationship between the crystal orientation and the magnetic properties, the pole figure was measured by X-ray diffraction method. In the case of single rolled reduction, the coercive force decreased with cold reduction ratio monotonically, but the maximum permeability, induction and squreness increased drastically. In the case of double rolled reduction (total reduction ratio is 90%), the saturation and residual induction increased slightly with secondary reduction ratio, but the maximum permeability and the coercive force had the maximum and the minimum value at the 50/50% reduction ratio respectively. And strong {100} <100> pole was developed by increasing the cold reduction ratio.

• 동력기계공학회지
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• 제13권3호
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• pp.47-52
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• 2009

The effect of forging start temperature, forging ratio on the microstructure and mechanical properties of B7B4 steel ware investigated. Microstructure of centrifugal casted B7B4 steel consisted of martensite and ferrite phase. The volume fraction of ferrite increased with increase of forging start temperature and decreased with increase of forging ratio. Tensile strength and hardness decreased with higher of forging start temperature, while impact value and elongation increased with higher of forging start temperature. With increase of forging ratio, tensile strength rapidly increased up to the forging ratio of 30%, and then slowly increased, but elongation was decreased. Hardness and impact value rapidly increased with increase of forging ratio.

• 대한치과보철학회지
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• 제16권1호
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• pp.45-47
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• 1978

We use investment to retain the mould of the wax pattern in making dental metal castings. A fin on the metal casting is occasionally formed due to several factors. The factors making the fin are improper burn out time and temperature, improper W/P ratio of investment and lining of asbestos in casting ring. The purpose of this study is to investigate the effect of W/P ratio of investment on the fin formation. Except the W/P ratio of investment which used to invest the wax pattern, the study was done under same condition; burn out time and temperature, W/P ratio of refractory cast(W/P=0.12) and asbestos lining in casting ring. The obtained result is that the fin is more likely to be formed on the casting which invested with higher W/P ratio of investment to that of refractory cast.

• Journal of Ship and Ocean Technology
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• 제12권3호
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• pp.14-25
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• 2008

Recently, there has been a serious effort to design a wing in ground effect (WIG) craft. Vehicles of this type might use low aspect ratio wings defined as those with smaller than 3. Design and prediction techniques for fixed wings of relatively large aspect ratio are reasonably well developed. However, Aerodynamic problems related to vortex lift on wings of low aspect ratio have made it difficult to use existing techniques. In this work, we firstly focus on understanding aerodynamic characteristics of low aspect ratio wings and comparing the results from experimental measurements and currently available numerical predictions for both inviscid and viscous flows. Second, we apply an improved numerical method, "B-spline based high panel method with wake roll-up modeling", to the same problem.

• Journal of Ceramic Processing Research
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• 제13권spc2호
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• pp.403-406
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• 2012

Effect of thickness on ZnO properties including the compositional ratio and crystallinity has been systematically investigated using a variety of characterization tools of x-ray diffraction, field emission scanning electron microscopy, x-ray fluorescence and x-ray photoelectron spectroscopy. Interestingly, it was observed that ZnO films below 80 nm in thickness were in oxygen deficiency, while the oxygen ratio was increased in the films above the thickness, although the compositional ratio of ZnO film was not linearly varied with increasing film thickness. Also, ZnO crystallinity, which is characterized by (002) diffraction pattern, was clearly improved with increasing film thickness. The properties of ZnO film with different sputtering time and the nature of direct current reactive sputtering process were discussed in terms of compositional ratio, especially oxygen ratio in ZnO film.

• 아태비즈니스연구
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• 제12권3호
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• pp.329-342
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• 2021

Purpose - The purpose of this study is to analyze the effect of investment by the National Pension Service, which has a high share as a single fund, on the dividend payout ratio. Design/methodology/approach - This study secured a share through DART of the Financial Supervisory Service and disclosure of the National Pension Service. We also used a fixed-effects model and 2SLS to analyze the data. Findings - First, it was found that there was a possibility of conflicting interests among shareholders concerning the company's dividend payment policy. Second, in the range of 3% to 4.9% of the National Pension Service shareholding, an additional increase in the holding ratio was found to have a positive (+) effect on the dividend rate. Third, after the introduction of the Stewardship Code, it was found that the increase in ownership of the fund had a positive (+) effect on the company's dividend payout ratio, regardless of the share ratio range. Moreover, the relationship between the fund ownership and the dividend payout ratio showed a clear positive relationship when free cash flow was high along investment opportunities were low. Research implications or Originality - First, This study included less than 5% of the share in the analysis. Second, We used the recent changes in fund shareholder activities. Third, We tested an instrumental variable to confirm the relationship between the National Pension Service share and the dividend ratio.

• 식물병연구
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• 제20권2호
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• pp.95-100
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• 2014

본 연구는 에스필과 수산화동의 혼용에 의한 오이, 토마토, 고추의 흰가루병에 대한 방제 효과를 구명하고자 수행하였다. 오이 흰가루병에서 에스필과 수산화동의 혼용 처리는 4 : 1 혼용처리구에서 발병엽률 18.9%와 방제효과 69.9%, 8 : 1 혼용 처리구에서 발병엽률 18.1%와 방제효과 71.1%로 가장 효과적이었다. 토마토 흰가루병에서 에스필과 수산화동의 혼용 처리는 4 : 1 혼용 처리구에서 발병엽률 12.4%와 방제효과 85.3%, 8 : 1 혼용 처리구에서 발병엽률 14.3%와 방제효과 83.0%로 가장 효과적이었다. 고추 흰가루병에서 에스필과 수산화동의 혼용 처리는 4 : 1 혼용 처리구에서 발병엽률 17.7%와 방제효과 76.4%로 가장 효과적이었다. 이상의 결과를 종합할 때 에스필과 수산화동 혼용처리에 의한 오이와 토마토 흰가루병에 대한 방제 효과는 4 : 1 혹은 8 : 1 혼용 처리가 가장 효과적이고, 고추 흰가루병에서는 4 : 1 혼용 처리가 가장 효과적인 방제 방법으로 구명되었다.