• Computers and Concrete
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• 제19권2호
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• pp.171-177
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• 2017

Water pressure test operation is used before the grouting to determine the rate of penetrability, the necessity and estimations related to grouting, by the penetration of water into the borehole. One of the parameters which have the highest effect is pressure of water penetration since the application of excessive pressure causes the hydraulic fracture to occur in the rock mass, and on the other hand, it must not be so small that prevents from seeing mechanical weaknesses and the rate of permeability. Mathematical modeling is used for the first time in this study to determine the optimum pressure. Thus, the joints that exist in the rock mass are simulated using cylindrical shell model. The joint surroundings are also modeled through Pasternak environment. To obtain equations governing the joints and the surroundings, energy method is used accompanied by Hamilton principle and an analytical solution method is used to obtain the maximum pressure. In order to validate the modeling, the pressure values obtained by the model were used in the sites of Seymareh and Aghbolagh dams and the relative error rates were measured considering the differences between calculated and actual pressures. Modeling in the sections of Seymareh dam showed 4.75, 3.93, 4.8 percent error rates and in the sections of Aghbolagh dam it rendered the values of 22.43, 5.22, 2.6 percent. The results indicate that this modeling can be used to estimate the amount of pressure for hydraulic fracture in water pressure test, to predict it and to prevent it.

• 한국산학기술학회논문지
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• 제8권1호
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• pp.103-109
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• 2007

본 논문에서는 시스템 파라미터의 변동이나 모델의 불확실성 및 외부 외란 등에 강인한 외란 관측기에 기초로 한 강인 제어기의 설계를 제안한다. 제어기는 두 개 루프의 구조를 갖는 모델기반 보상기와 궤환 제어기 구조로 구성되어 있다. 내부 루프 보상기는 내외부의 외란을 제거하고, 외부 루프 궤환 제어기는 주어진 사양을 만족하도록 하는 역할을 수행한다. 결과적으로, 제안한 강인 제어기를 이용함으로써 외란에 대해 시스템을 안정화시킬 수 있으며, 제어 성능을 향상시킬 수 있음을 보인다.

• Clinical and Experimental Reproductive Medicine
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• 제25권3호
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• pp.315-322
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• 1998

본 연구는 xanthine과 xanthine oxidase가 첨가된 배양액내에서 전배양된 돼지동결정액의 수정능력에 있어서 catalase의 영향을 검토하였다. 체외수정을 위한 기본 배양액내에서 0 또는 30분간 전배양한 정자는 catalase를 첨가 (40 및 15%)한 경우 보다는 무첨가 (66 및 38%)시 유의적으로 높은 정자침입율을 나타냈지만 (p<0.05), 배양액내에 xanthine을 첨가해 정자를 0, 30 및 60분간 전배양했을 때에는 catalase 무첨가 (33, 41 및 19%) 보다는 첨가시 (68, 70 및 49%) 유의적으로 높은 정자침입율이 인정되었다 (p<0.05). 그러나 xanthine oxidase를 첨가하여 정자의 전배양을 행하지 않은 경우는 catalase의 첨가 (13%) 보다는 무첨가 (51%)시 유의적으로 높은 정자침입율을 나타냈지만 (p<0.01), 전배양(30 및 60분)후에는 catalase의 존재유무와 정자전배양시간에 관계없이 매우 낮은 정자침입율 $(10\sim21%)$을 나타냈다. xanthine과 xanthine oxidase를 동시에 첨가하여 0, 30 및 60분간 정자를 전배양한 경우 catalase의 무첨가 (14, 4 및 8%)보다 첨가 (75, 55 및 52%)시 유의적으로 높은 정자침입율을 나타냈다 (p<0.001). 한편, 다정자침입율은 xanthine, xanthine+xanthine oxidase의 첨가시 정자전배양기간이 길어짐에 따라 감소하였으며, catalase의 첨가보다는 무첨가시 낮은 다정자침입율을 나타냈다. 본 연구의 결과로부터 xanthine과 xanthine oxidase를 동시에 첨가시 catalase의 존재는 정자의 전배양후에도 다정자침입을 억제하면서 수정능력의 유지를 위해 매우 효과적인 것으로 추측되었다.

• 한국터널지하공간학회 논문집
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• 제21권4호
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• pp.519-534
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• 2019

최근 국내 터널공사에서 낙반사고의 위험성이 낮고 진동과 소음이 적은 쉴드 TBM을 이용한 기계화 터널공법이 많이 적용되는 추세이며, 이러한 쉴드 TBM으로 터널 굴착 시 적절한 굴착속도를 설계하는 것이 무엇보다 중요하다. 본 연구에서는 ${\bigcirc}{\bigcirc}{\sim}{\bigcirc}{\bigcirc}$ 고속철도 쉴드 TBM 공사구간에 대하여 지반조사 결과와 TBM 굴진데이터를 분석하고 이를 기존 연구자들에 의해 제안된 경험적 굴착속도 예측방법에 적용하였다. 또한, 현장 굴진데이터 중 커터 당 추력과 지반 일축압축강도와의 상관관계를 분석하고 이를 통해 TBM 터널 설계 시 커터 당 추력과 일축압축강도를 변수로 굴착속도를 예측할 수 있는 간편 모델을 도출하였다. 기존 해외의 여러 굴착속도 예측 모델들을 해당 TBM 현장에 적용한 결과 예측치와 측정된 굴착속도는 약 50~500%의 비교적 큰 오차를 보인 반면, 본 연구에서 도출된 굴착속도 예측모델은 평균 약 15%의 오차율을 나타내어 추후 유사한 지반조건을 가진 쉴드 TBM 현장에 대해서 적용성이 높을 수 있을 것으로 기대한다.

• The Plant Pathology Journal
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• 제26권2호
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• pp.149-153
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• 2010

Biological and structural mechanisms of the nematode disease development in chili pepper caused by the root-knot nematode, Meloidogyne incognita, were investigated. Out of 39 chili pepper cultivars/lines tested, six were found resistant, while 33 were susceptible to M. incognita, of which a susceptible cultivar Chilseongcho and three resistant cultivar/lines CM334, 02G132 and 03G53 with different resistance degrees were selected for microscopic studies on the disease development. Gall formation was greatly reduced in the resistant cultivars/lines. Nematode penetration occurred both in the susceptible and resistant chili pepper roots; however, the penetration rates were significantly lowered in the three resistant peppers compared to the susceptible pepper cv. Chilseongcho. In the susceptible pepper, giant cells were extensively formed with no discernible necrosis around the nematode feeding sites. In the highly resistant pepper cultivar CM334, no giant cell was formed, but extensive necrosis formation was observed around the penetrating nematodes. In the other two resistant pepper lines (02G132 and 03G53), both giant cells and prominent necroses were formed, and the necrotic responses appeared to inhibit the further development of giant cells or accelerate their early degeneration. Although the nematode penetration was retarded significantly in the resistant cultivar/lines, all of the above results suggest that the disease resistance of pepper may be related to post-infectional defense mechanisms (nematode growth and development) more than pre-infectional ones (penetration and establishment). Variations in structural modifications in the resistant cultivar/lines may reflect their genetic differences related to the nematode resistance.

• 한국건축시공학회지
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• 제9권6호
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• pp.71-78
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• 2009

하중을 고려한 염분침투성의 평가가 대단히 중요한 것으로 확인되었다. 본 연구에서는 압축응력하에서 Plain콘크리트에서는 47%정도, BFS콘크리트에서는 89%정도 증가 하는 것으로 나타났다. 무하중 상태에서 BFS를 혼입한 콘크리트의 확산계수가 BFS 무혼입 콘크리트에 비해 적은 것이 확인되었다. 이러한 영향은 압축응력이 발생하는 환경하에서도 같은 경향을 나타내었다. 압축응력이 작용하는 환경 하에서 BFS콘크리트는 Plain콘크리트와 같이 하중의 증가와 함께 확산계수가 증가하는 것으로 확인 되었다. 또한, Plain콘크리트에 비해 압축하중의 영향을 크게 받는 것으로 확인 되었다. BFS의 비표면적이 높을수록 확산 계수가 작은 것으로 확인되었고, 이러한 경향은 고응력 환경에서 현저히 나타나는 것이 확인되었다. BFS의 치환율이 증가할수록 확산계수가 작은 것이 확인되었다. 또한, 압축응력이 작용하는 환경 하에서 BFS의 치환에 의한 염분침투성의 억제 효과가 더욱 더 현저히 나타나는 것으로 확인되었다.

• Toxicological Research
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• 제17권4호
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• pp.317-323
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• 2001

The skin penetration rate of methidathion in vitro and pharmacokinetics of methidathion in vivo were studied with male Sprague-Dawley rats by dermal treatment. The in vitro skin penetration rates for Sprague-Dawley rats of methidathion technical (50 mg, 100 ${mu}ell$) and emulsifable concentrate (EC,40mg, 100${mu}ell$) were determined as 18.4 $\mu\textrm{g}$/c $m^2$/h (RSD : 6.5) and 18.5 $\mu\textrm{g}$/c $m^2$/h (RSD : 3.2), respectively. Dose-related systemic exposure (AUC) was observed in rats after dermal treatment. The corresponding AUC, $T_{max}$, $C_{max}$, and $T_{1}$2/ of methidathion in plasma were 1.5$\mu\textrm{g}$.hr/ml, 6 h, 0.10 $\mu\textrm{g}$/ml, and 16 h, for 116mg/kg doses, 3.2 $\mu\textrm{g}$. hr/ml, 8 h, 0.12 $\mu\textrm{g}$/ml, and 23 h, for 232 mg/kg doses and 10 $\mu\textrm{g}$. hr/ml, 12 h, 0.32 $\mu\textrm{g}$/ml, and 20 h, for 1,160 mg/kg doses respectively. The urinary excretion of methidathion, estimated wing an equation derived from the in vitro skin penetration study was 0.24~0.35% of the absorbed dose. The concentration of methidathion in kidney was higher than that in liver. Dose-dependent absorption and excretion of methidathion without saturation was observed under in vivo experimental condition.n.n.

• Asian-Australasian Journal of Animal Sciences
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• 제15권2호
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• pp.172-178
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• 2002

The present study examined whether treatment of in vitro matured pig oocytes with calcium ionophore (A23187) could prevent polyspermic penetration in vitro. When oocytes cultured for maturation for 33, 36 or 44 h were subsequently treated with $50{\mu}M$ A23187 in medium with fetal calf serum (FCS) for 1, 2 and 3 h and then cultured for 12 h without spermatozoa, virtually no activation occurred. In the absence of FCS, however, 31-42, 45-49 and 56-64% of oocytes were activated, respectively. When oocytes treated with $50 {\mu}M$ A23187 in medium with FCS for 3 h were inseminated in vitro, the penetration rates (14-57%) were lower (p<0.01) with a higher (p<0.01) incidence (35-67%) of monospermy compared with untreated oocytes (69-80% penetration and 15-17% monospermy). However, sperm penetration was completely blocked in all oocytes treated with A23187 in the absence of FCS. When oocytes matured for 33 h were treated with different concentrations of A23187 for 3 h and inseminated in vitro, the penetration rate did not change but there was an increased incidence (p<0.05) of monospermy at $10-20{\mu}M$ and $2.5-5{\mu}M$ A23187 in the presence and absence of FCS, respectively, compared with at $0{\mu}M$ A23187. With these lower concentrations of A23187, treatment of oocytes for at least 60 and 30 min in the presence and absence of FCS, respectively, was required to increase the incidence of monospermy without reducing penetration rate. These results indicate that a high concentration ($50{\mu}M$) of A23187 in medium without FCS, but not in medium with FCS, stimulated in vitro matured pig oocytes to induce parthenogenetic activation and a complete block to sperm penetration in vitro. However, treatment of oocytes with lower concentrations of A23187 ( $10-20{\mu}M$ and $2.5-5{\mu}M$) both in the presence and absence of FCS maintained sperm penetration in vitro and increased the incidence of monospermy.

• 한국분무공학회지
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• 제6권3호
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• pp.38-44
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• 2001

The effect of four diesel fuels with oxygenated agents fuels on spray properties from plain-orifice atomizer was investigated. The oxygenates evaluated were diglyme, MTBE, DEE and DMM and were blended in weights of 5, 10, 15, 20 and 30% in a baseline diesel fuel. The physical properties such as surface tension, density and viscosity are also measured for each blended oxygenated fuels. It was found that changes in physical properties of fuels considered are enough to influence spray properties, i.e. spray angle, spray tip penetration and mean drop size. Spray properties were measured by PMAS(particle motion analysis system) which is employing a point measurement technology. Spray angle increased with increase in oxygenate content. The effect, however, was not great in the higher blend level. The oxygenated fuels produced more shorter spray tip penetration than diesel fuels. SMD was decreased with the increase in blending percent. SMD for DMM and DEE are represented 10.33 and 3.41% decreasing rates respectively. It was found that changes in spray characteristics of oxygenated fuel were easily large enough to impact pollutant emissions. It was clear from this study that spray characteristics of oxygenated fuel is one of possible cause of reducing pollutant emissions. It was clear from this study that spray characteristics of oxygenated fuel is one of possible cause of reducing pollutant emissions from diesel engines when oxygenated fuels is applied.

• Structural Engineering and Mechanics
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• 제44권6호
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• pp.801-814
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• 2012

The strain rate effects on the interaction between a Mode I matrix crack and an inclined elliptic matrix-inclusion interface under dynamic tensile loadings were investigated numerically, and the results are in agreement with previous experimental data. It is found, for a given material system, that there are the first and the second critical strain rates, by which three kinds of the subsequent crack growth patterns can be classified in turn with the increasing strain rate, namely, the crack deflection, the double crack mode and the perpendicular crack penetration. Moreover, such a crack deflection/penetration behavior is found to be dependent on the relative interfacial strength, the inclined angle and the inclusion size. In addition, it is shown that the so-called strain rate effect on the dynamic strength of granule composites can be induced directly from the structural dynamic response of materials, not be entirely an intrinsic material property.