• 한국환경과학회지
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• 제22권12호
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• pp.1661-1669
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• 2013

This study conducted a laboratory simulation using artificial and natural rainfall in order to investigate the runoff characteristics of livestock resources through the analysis of the surface runoff water and infiltration water by rainfall intensity and fertilization level. Cattle manure and pig liquid fertilizer was used as livestock resource. As a result of this study, it was observed that the surface runoff occurred over 32 mm/hr rainfall intensity, and flow rate of the surface runoff water and the runoff ratio of contaminant parameters from livestock resource was increased, as rainfall intensity was stronger. With doubled fertilization level, T-N increased in compost and the amount of $COD_{Mn}$ runoff also considerably increased in liquefied fertilizer. In the case of natural rainfall, the runoff ratio of T-P clearly increased in compost and the T-N of final surface runoff ratio in compost and liquefied fertilizer was ranged from 0.13047 to 0.13623 with stronger rainfall intensity.

• 한국산림과학회지
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• 제76권3호
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• pp.218-229
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• 1987

본(本) 연구(硏究)는 광환경(光環境) 및 근장(根長)의 정도(程度)를 각기 달리한 잣나무 유묘(幼苗)의 중량(重量) 생장(生長)을 측정(測定) 고찰(考察)한 것으로 그 결과(結果)는 다음과 같았다. 1) 묘목(苗木)의 중량(重量) 생장(生長)은 상대광도(相對光度) 63%구(區)가 가장 높게 나타났으나 전체적(全體的)으로는 피음(被陰)의 정도(程度)가 강(強)할 수록 점차(漸次)로 감소(減少)하는 경향(傾向)을 보였으며, 단근(斷根) 처리(處理)의 경우는 1/4 단근구(斷根區)가 타(他) 처리구(處理區)에 비(比)해 제일 높았다. 2) 묘목(苗木)의 T/R율(率)값은 광도(光度)가 낮았을 때와 단근(斷根) 정도(程度)가 강(強)할 수록 각각(各各) 그 값이 점차(漸次)로 높게 나타나서 결국(結局) 피음(被陰) 및 단근(斷根)의 정도(程度)가 강(強)할 수록 묘목(苗木)의 생장(生長)은 약세(弱勢)를 나타냈다. 3) 그리고 광도(光度) 및 단근량(斷根量)과 T/R율(率) 간(間)에는 2차(次) 회귀관계(回歸關係)에 있음을 알 수 있었다.

• 한국재료학회지
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• 제21권9호
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• pp.509-514
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• 2011

In this study, optical emission spectroscopy was used to monitor the plasma produced during the RF magnetron sputtering of a $BaTiO_3$ target. The intensities of chemical species were measured by real time monitoring with various discharge parameters such as RF power, pressure, and discharge gas. The emission lines of elemental and ionized species from $BaTiO_3$ and Ti targets were analyzed to evaluate the film composition and the optimized growth conditions for $BaTiO_3$ films. The emissions from Ar(I, II), Ba(I, II) and Ti(I) were found during sputtering of the $BaTiO_3$ target in Ar atmosphere. With increasing RF power, all the line intensities increased because the electron density increased with increasing RF power. When the Ar pressure increased, the Ba(II) and Ti(I) line intensity increased, but the $Ar^+$ line intensity decreased with increasing pressure. This result shows that high pressure is of greater benefit for the ionization of Ba than for that of Ar. Oxygen depressed the intensity of the plasma more than Ar did. When the Ar/$O_2$ ratio decreased, the intensity of Ba decreased more sharply than that of Ti. This result indicates that the plasma composition strongly depends on the discharge gas atmosphere. When the oxygen increased, the Ba/Ti ratio and the thickness of the films decreased. The emission spectra showed consistent variation with applied power to the Ti target during co-sputtering of the $BaTiO_3$ and Ti targets. The co-sputtered films showed a Ba/Ti ratio of 1.05 to 0.73 with applied power to the Ti target. The films with different Ba/Ti ratios showed changes in grain size. Ti excess films annealed at $600^{\circ}C$ did not show the second phase such as $BaTi_2O_5$ and $TiO_2$.

• 한국식품과학회지
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• 제31권6호
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• pp.1679-1682
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• 1999

본 연구는 고춧가루 추출액의 혼합 비율에 따른 고추씨 추출액의 매운맛에 대한 영향을 조사하기 위하여 수행되었다. 고추씨 추출액에 첨가하는 고춧가루 혼합비율이 증가할수록 수율 및 점도, 탁도, a와 b값은 증가하였으며 L값은 감소하는 경향을 보였다. 또한 시간차 강도 평가에 의한 관능검사 결과 고추씨 추출액은 매운맛이 완만히 증가하였으며 후기에도 그 강도가 유지되는 것에 반하여 고춧가루 추출액은 단시간에 매운맛에 도달한 후 급격히 감소하는 경향을 나타내었다. 고춧가루와 고추씨 추출액의 혼합 비율은 그들 자체가 지니는 매운맛 특성에 의해 영향을 받음을 알 수 있었다.

• 한국자동차공학회논문집
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• 제6권4호
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• pp.121-128
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• 1998

In this study, when tension and bending stress act on plate simultaneously, stress intensity factor is analyzed at crack tip with using BEM(Boundary Element Method). In this analysis, stress intensity factors(S.I.F) are defined for variable ligament, aspect and stress ratio($\sigma$T/$\sigma$B). Consequently, predicted that crack grow to depth direction at low aspect and ligament ratio in tension stress and to surface direction in bending stress. Tension and bending stress act on plate same time, effect of tension stress in the first stage and effect of bending stress in the after stage was to observed. The outbreak of secondary crack in backside is under the control of stress amplitude and predict that the point of outbreak is mear backside.

• 한국안전학회지
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• 제13권3호
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• pp.24-31
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• 1998

Variable thickness plates are commonly encountered in the majority of mechanical/structural components of industrial applications. And, as a result of the unsymmetry of the structure or the load and the anisoptropy of the materials, the cracks in engineering structures are generally subjected to combined stresses. In spite of considerable practical interest, however, a few fracture mechanics study on combined mode crack in a variable thickness plate have carried out. In this respect, combined mode I/III stress intensity factors $K_I$ and $K_III$ at the crack tip for a variable thickness plate were obtained by 3-dimensional finite element analysis. Variable thickness plates containing a central slant crack were chosen. The parameters used in this study were dimensionless crack length $\lamda$, crack slant angle $\alpha$, thickness ratio $\beta$ and width ratio $\omega$. Stress intensity factors were calculated by crack opening displacement(COD) and crack tearing displacement(CTD) method.

• 한국정밀공학회지
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• 제14권4호
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• pp.136-144
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• 1997

The characteristics of fatigue crack growth subject to out-of-plane bending fatigue are studied in terms of crack opening behavior by using pre-cracked smooth specimens. Crack opening stress is measured by an elastic compliance method which may precisely and continuously provide many date using strain gages during experiment. The results of the short crack and the long crack arranged by crack closure concept show that the effective stress gange ratio of short crack is grester than that of long crack, and ano- malous growth behavior of short crack may be elucidated by the variation of crack opening stress. When the variation of fatigue crack growth rate is arranged versus effective stress intensity factor range. Iinear relation is held also for the short crack. It shows that growth behavior of short crack can be quantitatively represent- ed by the fracture mechanics parameter using effective stress intensity factor range.

• 청정기술
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• 제18권4호
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• pp.404-409
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• 2012

본 연구는 교반강도 및 응집제 주입량의 변화에 따라 플럭의 성장특성이 인의 제거에 미치는 영향을 파악하고자 수행되었다. 본 연구에서는 Al/P 몰비를 1.0, 1.5와 2.0으로 급속혼화강도 G값을 100, 300과 500 $s^{-1}$로 변화시켜 수행하였다. 응집시 발생되는 응집지수(floc size index, FSI)와 크기가 다른 여과지를 이용하여 인의 제거율을 측정하여 성장 특성을 파악하였다. 연구결과 교반강도가 높을수록 용존인의 제거효율이 증가하였으며 Al/P 몰비가 낮을수록 교반강도의 영향이 컸다. T-P의 제거율은 Al/P 몰비 1.0 이하에서는 급속혼화 교반강도가 높을수록 높았으나 Al/P 몰비 1.0 이상에서는 G값 300 $s^{-1}$에서 가장 높은 제거 효율을 나타내었다. Al/P 비 1.0 이하에서는 G값 500 $s^{-1}$에서 가장 큰 FSI값을 나타내었으며, Al/P 몰비 1.0 이상에서는 G값 300 $s^{-1}$에서 가장 큰 FSI값을 나타내었다. 실제하수처리장 유출수를 대상으로 응집에 의한 인 제거에 Al/P 몰비와 급속혼화 강도의 영향은 인공조제수의 결과와 유사하였다.

• 한국해양공학회지
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• 제7권1호
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• pp.124-132
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• 1993

In order to examine the effect of anisotropy and stress ratio on fatigue crack propagation rate and opening-closing behavior and also arrest behavior by single tension peak overload, the fatigue tests of constant amplitude atress and single tension peak overload adding to cycle of constant amplitude were carried out in stress ratio of -0.4, -0.2, and 0.4 with materials of T-L and L-T directions in 2024-T3 aluminum alloy plate. Crack opening-closing begavior were measured by the compliance method using COD gage and strain gage. In case of the crack opening-closing behavior was measured by strain gage, the effect of stress ratio is unchangeable. But in the case of COD gage, that is remarkably decreased. Fictitious effective stress intensity factor(U sub(f)) and effective stress intensity factor ratio(U) in L-T direction was higher than those in T-L direction and also threshold arrest overload ratio incrased as stress ratio decreased and that of T-L direction was higher than that in L-T direction.

• Structural Engineering and Mechanics
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• 제30권3호
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• pp.317-330
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• 2008

Stress intensity factors for a planar crack parallel to a bimaterial interface are considered. The formulation leads to a system of hypersingular integral equations whose unknowns are three modes of crack opening displacements. In the numerical analysis, the unknown displacement discontinuities are approximated by the products of the fundamental density functions and polynomials. The numerical results show that the present method yields smooth variations of stress intensity factors along the crack front accurately. The mixed mode stress intensity factors are indicated in tables and figures with varying the shape of crack, distance from the interface, and elastic constants. It is found that the maximum stress intensity factors normalized by root area are always insensitive to the crack aspect ratio. They are given in a form of formula useful for engineering applications.