• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.2
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• pp.195-204
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• 2004

A series of constant creep and repeated creep tests are performed to investigate the behavior of visco-elasto-plastic materials of chemical grouted sands. In the result of constant creep test, the material exhibits three types of shear strain : elastic, plastic, viscoelastic. The elastic, plastic and viscoelastic strains are linear, i.e., the strains are proportional to the stresses for loading. Good agreement is found between the predicted viscoelastic and test results by the power law and the generalized model. In the repeated creep test, the instantaneous recoverable strain is time-independent and the magnitude of accumulated plastic strain increases with number of cycles. Also it is seen that the accumulated plastic strains are approximately proportional to stress. There are no significant differences between test results predicted values for first cycle, and the differences increase relatively insignificantly with number of cycles.

• The Korean Journal of Pharmacology
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• v.32 no.1
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• pp.31-37
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• 1996

The protective effect of 'ischemic preconditioning (IP)'on ischemia-reperfusion injury of heart has been reported in various animal species, but the mechanism is unclear. In an attempt to elucidate the mechanism of IP, we examined the effects of blockers against adenosine and protein kinase C in preconditioned heart of rat. The hearts perfused with oxygen-saturated Krebs-Henseleit solution by Langendorff method were exposed to 30 min global ischemia followed by 20 min reperfusion. IP was performed with three episodes of 5 min ischcmia and 5 min reperfusion just before ischemia-reperfusion. IP prevented the depression of contractile function and the myocardial contracture in the ischemic-reperfused heart and reduced the release of lactate dehydrogenase during the reperfusion period. Polymyxin B, chelerythrine and colchicine, PKC inhibitors, attenuated almost completely the anti-ischemic effect of IP, while adenosine receptor antagonists did not. These results indicate that PKC may be a crucial intracellular mediator in anti-ischemic action of IP in ischemic-reperfused rat heart, while adenosine may not be involved in the mechanism of IP.

• Childhood Kidney Diseases
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• v.14 no.2
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• pp.195-202
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• 2010

Purpose : The purpose of this study is to determine if there are prognostic factors leading to permanent parenchymal damages to kidney in children after acute pyelonephritis. Methods : This study was conducted in 160 pediatric patients with acute pyelonephritis admitted to Ajou University Hospital from 2000 to 2005, whose renal cortical defects were confirmed by $^{99m}Tc$-dimercaptosuccinic acid scintigraphy (DMSA scan). Along with the follow-up DMSA scan after 6 months, they were classified into two groups; recovered group (106) and scarred group (54). The clinical characteristics of each group were compared. Results : Among the total of 160 patients, 106 (66.3%) showed recovery of the initial defect (the recovered group), while 54 (33.8%) showed permanent defects on the followup DMSA scan (scarred group). Recovery rate was poor for patients of 1 year and older, or patients with the duration of fever and pyuria longer than 7 days. The recovery rate was poor in the patients with history of frequent febrile episodes and abnormal results of imaging studies, such as voiding cystourethrography (VCUG), ultrasonography. Conclusion : The recovery rate of children with renal defects on DMSA scan with acute pyelonephritis was lower when the patient is older than 1 year, when the duration of fever and pyuria exceeded 7 days, and when the patients had the histories of frequent febrile episodes and had urinary tract abnormalities on imaging studies. These findings suggest that there may be under- or mis-diagnosis of acute pyelonephritis by pediatrician.

• The Korean Journal of Malacology
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• v.29 no.3
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• pp.225-232
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• 2013

This study looked into recovery rate and histological changes in the gills of juvenile abalone Haliotis discus hannai by exposure time (3, 6, 12, 24 and 48 h) of different water temperatures (15, 20 and $25^{\circ}C$) and salinities (30, 25, 20 and 15 psu) to understand reasons for the death of abalone exposed by low salinity water. In each water temperature, abalone spats that were exposed to low salinity water (less than 20 psu) for over 6 hours showed decrease in survival rate during recovery and those were exposed at the salinity of 15 psu for more than 24 hours all died. Histological observation showed expansion or damage of gills of the species which were exposed at less than 20 psu for over 6 hours. In case of abalones exposed at the salinity of 15 psu for over 24 hours, most gill tissues were destroyed. This result was glaringly obvious at a higher water temperature, lower salinity and longer exposure time. Accordingly, suffocation caused by damage of gills considered one of direct causes of the death.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2C
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• pp.71-79
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• 2009

This study is to develope the resilient modulus prediction model, which is the function of mean effective principal stress and axial strain, for three types of railroad trackbed materials such as crushed stone, weathered granite soil, and crushed-rock soil mixture. The model consists of the maximum Young's modulus and nonlinear values for higher strain, analogous to dynamic shear modulus. The maximum value is modeled by model parameters, $A_E$ and the power of mean effective principal stress, $n_E$. The nonlinear portion is represented by modified hyperbolic model, with the model parameters of reference strain, ${\varepsilon}_r$ and curvature coefficient, a. To assess the performance of the prediction models proposed herein, the elastic response of a test trackbed near PyeongTaek, Korea, was evaluated using a 3-D elastic multilayer computer program (GEOTRACK). The results were compared with measured elastic vertical displacement during the passages of freight and passenger trains at two locations, whose sub-ballasts were crushed stone and weathered granite soil, respectively. The calculated vertical displacements of the sub-ballasts are within the order of 0.6mm, and agree well with measured values. The prediction models are thus concluded to work properly in the preliminary investigation.

• Feed Journal
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• v.2 no.7
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• pp.90-93
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• 2004

소에 있어서의 하절기 고온다습은 체력의 저하와 평상시에 비해 사료섭취량의 감소로 인한 유량이나 유질 등의 우유생산성, 분만 후 생식기의 회복이 지연되어 자궁내막염이 많이 발생됨에 따라 번식률이 저하되는 등 나쁜 영향을 미칠 뿐만 아니라 질병발생이 많아지게 한다.<중략>

• The monthly packaging world
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• s.15
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• pp.49-53
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• 1994

PET 용기는 경제성 등 다른 용기에 비해 여러 이점으로 널리 사용돼와 80년대 중반 이후 매년 30퍼센트 이상의 고속성장을 해왔지만 90년대 들어서는 경기불황의 여파로 성장률이 떨어지고 있다. 특히 환경에 대한 관심과 일회용 용기 사용 규제 등으로 지난해에는 최악의 상황에 빠지기도 했다. 올해 들어 경기가 다소 회복되고, 업계에서도 용기규격의 다양화와 적극적인 환경대응을 위한 투자에 나서 판매신장을 꾀하고 있다. 이 글에서는 PET 용기의 제조기술과

• The monthly packaging world
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• s.15
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• pp.64-67
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• 1994

지난 10년간 연평균 40퍼센트의 성장률을 기록해왔던 음료시장이 최근 몇년간 경기 침체와 신제품 개발 부진 등으로 성장이 둔화되고 있다. 따라서 관련용기시장도 부침을 같이 해왔는데, 특히 설비과잉의 제관업계의 경우 근래 경기 회복의 기미에 따라 새로운 도약의 기회를 맞고 있다. 용도 확대 등 신제품 개발, 경량화, 스틸캔 등 재활용체계 마련, 수출시장 개척 등을 통해 올해10퍼센트 안팎의 성장이 기대되는 캔시장을 살펴본다.

• The monthly packaging world
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• s.40
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• pp.56-64
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• 1996

경제와 함께 성장을 이루는 석유화학산업은 1994년부터 세계 경기가 회복되는 가운데 하반기에는 미국, 일본 등지에서 석유화학공장의 대형사고가 잇달아 발생함에 따라 석유화학제품의 가격이 크게 상승하면서 경기가 호전되고 있다. 합성수지의 경우은 그동안 $10\%$의 성장률을 기록함으로써 화학산업의 성장을 이끌어 왔으나 1995년에는 극 성장세가 급격히 둔화되어 수요는 전년 수준에 머문 것으로 나타났다. 이렇듯 합성수지가 둔화된 이유는 지

• 비료회보
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• s.567
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• pp.10-18
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• 2004

1997년 아시아에 재정 위기가 닥치면서 태국의 비료 산업이 크게 타격을 입었으며 최근 몇 년 동안 그 회복이 빠르게 진행되지 않고 있다. 그러나 여기 David Hayes에 의하면, 비료 소비와 시장가격 그리고 국내 비료산업의 이익률이 결국에는 튼튼한 기초 위에 다시 되돌아 올 것이라는 희망이 주요 수출 부문에서 일고 있어 이러한 희망으로 인해 새로운 자본 유입이 태국의 농업과 가공 식품산업을 목표로 하여 합작이 이루어졌다고 했다.