• Journal of the Korea Concrete Institute
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• v.21 no.4
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• pp.531-537
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• 2009

In this study alkali reactivity of crushed stone was conducted according to the ASTM C 227 that is traditional mortar bar test, and C 1260 that is accelerated mortar bar test method. The morphology and chemical composition of products formed in mortar bar, 3 years after the mortar bar tests had been performed, were examined using scanning electron microscopy (SEM) with secondary electron imaging (SEI) and electron probe microanalysis (EPMA) with backscattered electron imaging (BSEI). The crushed stone used in this study was not identified as being reactive by ASTM C 227. However, mortar bars exceeded the limit for deleterious expansion in accelerated mortar bar test used KOH solution. The result of SEM (SEI) analysis, after the ASTM C 227 mortar bar test, confirmed that there were no reactive products and evidence of reaction between aggregate particles and cement paste. However, mortar bars exposed to alkali solution (KOH) indicated that crystallized products having rosette morphology were observed in the interior wall of pores. EPMA results of mortar bar by ASTM C 227 indicated that white dots were observed on the surface of particles and these products were identified as Al-ASR gels. It can be considered that the mortar bar by ASTM C 227 started to appear sign of alkali-silica reaction in normal condition. EPMA results of the mortar bar by ASTM C 1260 showed the gel accumulated in the pores and diffused in to the cement matrix through cracks, and gel in the pores were found to be richer in calcium compared to gel in cracks within aggregate particles. In this experimental study, damages to mortar bars due to alkali-silica reaction (ASR) were observed. Due to the increasing needs of crushed stones, it is considered that specifications and guidelines to prevent ASR in new concrete should be developed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.4
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• pp.272-281
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• 2007

선박제조업을 비롯한 운송업 및 건축업 등의 다양한 분야에서 용접기술이 이용되어 옴에 따라 용접근로자들에 대한 산업보건학적 관심이 높아지고 있다. 노출정도가 다양하기는 하지만 용접흄은 6가 크롬을 비롯한 금속화합물과 유해가스, 화학물질 등을 복합적으로 포함하고 있는 스테인레스 스틸 용접흄에 대한 유전독성영향을 평가하기 위하여 흡입챔버를 이용, 실험동물인 영장류에 스테인레스 스틸 용접흄을 노출시키고 혈액 내 lymphocytes에 생성된 용접흄 노출농도 및 시간별 DNA 손상정도 및 그 회복효소를 측정함으로써, 유해성이 완전하게 확인되지 않은 용접흄에 노출되어 나타날 수 있는 암을 비롯한 심각한 건강영향을 예방하기 위한 각 지표들을 찾아 그 유용성을 비교하고자 하였다. 영장류를 노출시키기 위해 robotic arm을 장치한 영장류 흡입노출 시스템을 개발하였으며, 이 노출 시스템을 이용하여 수컷 영장류 6마리에 대해 용접흄 노출시험을 실시하였는데 실험군은 대조군 2, 저농도 ($31mg/m^3$) 노출군 2, 고농도 ($63mg/m^3$) 노출군 2마리로 구성하였고, 1일 2시간씩 일주일에 5일 동안 용접흄에 노출시켰다. 노출 농도는 지속적으로 모니터링 하였고, 노출과정 중에 영장류의 혈액을 채취하여 lymphocytes를 분리, 단세포 DNA 손상을 선별하기 위해 DNA 손상회복 효소인 E. coli formamidopyrimidine-DNA glycosylase (Fpg)와 endonuclease Ⅲ (Thymine Glycol-DNA glycosylase) 투여와 Comet asaay (single cell gel electrophoresis, 단세포겔전기영동기법)를 결합시켜 이용하는 Fpg/Endo III FLARE 분석법을 사용하였다. Fpg enzyme에 의한 olive tail moment값의 변화는 16주 노출군부터 노출부검(34주)군 까지 노출농도가 높아짐에 따른 olive tail moment 기하평균 값의 양 반응관계를 보기는 어렵지만, 고농도군의 경우 27주 노출군에서 가장 높은 olive tail moment 값을 보이고 이후 차츰 감소하였다. 한편 16주에서 22주까지의 노출기간에서는 대조군에 비해 노출군에서 DNA손상정도(olive tail moment값)는 모두 유의하게 높았으나, 6, 12, 18, 25, 31, 33, 35주간 노출하였을 때는 다른 결과를 보였다. 각 실험군의 Fpg enzyme에 의한 tail length값의 분포를 살펴볼 때, 저농도군 및 고농도군에서 27주간 노출하였을 때 가장 높은 tail length 값을 보이고 이후 차츰 감소하는 경향을 보였다. 또한 16, 22주간 노출하였을 때 대조군에 비해 노출군에서 tail length 값이 유의하게 높았으나, 20주간에서만 양 반응관계가 관찰되었고, 다른 주간에서는 양 반응 및 기간 반응관계를 나타내지는 않았다. Endo III enzyme에 의한 olive tail moment값의 변화는 기간별 노출군에서 대조군에 비해 높은 DNA손상정도(olive tail moment값)를 나타내는 결과들이 있었지만, 10, 12, 16, 22, 25, 31주간 노출하였을 때 등 상당수 노출기간에서 반응관계를 나타내지는 않았다. 각 실험군의 Endo III enzyme에 의한 tail length값의 분포를 살펴볼 때, 18, 20, 27, 33주간 노출하였을 때 대조군에 비해 노출군에서 tail length 값이 조금 높았지만, 양 반응 및 기간 반응관계를 보이지 않았고 수치의 크기가 불규칙하게 변화하였다. 즉, DNA에 있어 산화된 pyrimidine을 형성하여 손상된 부위의 염기를 제거함으로써 AP site (abasic site)를 만들고 이들이 Comet assay를 통해 break로 전환된 것을 포함한 DNA손상을 측정하기 위하여 endonuclease III (Endo III)를 첨가시킨 Endo III FLARE 분석법을 실시한 결과, 본 연구에서 나타난 결과는 용접흄 노출 영장류에서 Olive tail moment 및 tail length 공히 노출량 및 노출기간 반응관계를 볼 수 없었다. Endo III FLARE 분석법을 통한 산화적 DNA 손상지표는 영장류에 적용하기에는 적응반응현상으로 대조군과 유의한 차이도 관찰할 수 없었고 더욱이 역으로 대조군에서의 자연발생적 수치가 더 높아질 수 있어 용접흄 노출 영장류의 모니터링 지표로 사용하기에는 제한점이 있었다.

• Journal of Arbitration Studies
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• v.24 no.2
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• pp.33-52
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• 2014

Although climate change is a global scale question, some concerns have been raised that principles of investment arbitration may not adequately address the domestic implementation of climate change measures. A recent ICSID investment arbitration of Vattenfall v. Germany with regard to the investor's alleged damages from the phase-out of nuclear plants is a salient climate change case. The 2005 Kyoto Protocol was made to reduce greenhouse gas emissions and it provides a number of flexible mechanisms such as Joint Implementation (JI) and Clean Development Mechanism (CDM). Implementation of the Kyoto Protocol allows dispute settlement through investor-state arbitration. Any initiation of stricter emission standards can violate the prohibition on expropriations in investment agreements, regardless of the measures created to reduce greenhouse gas emissions. The effect-based expropriation doctrine can charge changes to existing emission standards as interference with the use of property that goes against the legitimate expectation of a foreign investor. In regulatory chill, threat of investor claims against the host state may preclude the strengthening of climate change measures. Stabilization clauses also have a freezing effect on the hosting state's regulation and a new law applicable to the investment. In the fair and equitable standard, basic expectations of investors when entering into earlier carbon-intensive operations can be affected by a regulation seeking to change into a low-carbon approach. As seen in the Methanex tribunal, a non-discriminatory and public purpose of environmental protection measures should be considered as non-expropriation in the arbitral tribunal unless its decision would intentionally impede a foreign investor's investment.

• Journal of Animal Science and Technology
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• v.48 no.3
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• pp.443-452
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• 2006

The four rice(Oryza sativa L.) lines, previously demonstrated to have vigorous herbage production at the vegetative growth stage, were investigated for their growth traits, dry matter yield and feed value using the twice-cutting system that 1st-cut is harvested at panicle formation stage and 2nd-cut at the yellow ripen stage. The twice-cutting system is regarded as an effective method in the production of forage rice by escaping lodging and insect damages caused by the overgrowth and typhoon around the heading stage.The feed value of the twice-cut rice plant of there lines were compared with the control of normal, cutting at the yellow ripen stage. The relative feed value(RFV), the total digestible nutrient(TDN) and the crude protein(CP) content of the twice-cut straw were higher the control in every lines. However, the dry matter yield (DMY), represented by the summed forage production of 1st and 2nd cut-rice plant, were lower the control, and the DMY of straws were increase but grains were decrease for twice-cutting system. In addition, TDN yield showed the similar tendency with DMY.Recently, as one of the breeding aims the researches for improving the digestibility of rice straw have been required. In this regard, twice-cutting system is recognized with the fact that it has the effect which raises the digestibility of the straw. Especially, the 2nd cut of IR73111-B-R-15-3-1 line was similar to the control at the TDN yield of straw, and would be used as a breeding material for product the roughage of good quality.

• Journal of Life Science
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• v.18 no.12
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• pp.1718-1721
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• 2008

The skin of human is constantly being exposed to environmental irritants such as ultraviolet, smoke and chemicals. These irritants cause free radicals and reactive oxygen species which leave serious damages on the cells of skin. The water and ethanol extracts of Cambodian Phellinus linteus were investigated for the activities of anti-lipid peroxidation and anti-wrinkle effects to apply as a functional ingredient for cosmetic products. As the result of evaluation of liquid oxidation rate by add $Fe^{2+}$ and $Cu^{2+}$ to Cambodian Phellinus linteus extracts, Cambodian Phellinus linteus ethanol extracts were higher than Cambodian Phellinus linteus water extracts in the chealting ability of $Fe^{2+}$ and $Cu^{2+}$. The Cambodian Phellinus linteus ethanol extracts exhibited that anti-lipid peroxidation higher than butylated hydroxytoluene (BHT) at the concentration of 0.1 mg/ml, 0.5 mg/ml and 1 mg/ml. Cambodian Phellinus linteus water and ethanol extracts showed a higher inhibitory effect on $Fe^{2+}$-induced lipid peroxidation compared to $Cu^{2+}$-induced lipid peroxidation. In the case of anti-wrinkle effect, the elastase inhibition activity of Cambodian Phellinus linteus ethanol extracts was 50.7%, and it is higher than urosolic acid at the concentration of 0.01 mg/ml. Also, in collagenase inhibition activity, Cambodian Phellinus linteus water extract showed low effect, but Cambodian Phellinus linteus ethanol extract was about 50% at a 0.1 mg/ml. concentration. These results proved that Cambodian Phellinus linteus had anti-lipid peroxidation and anti-wrinkle effect. Therefore, Cambodian Phellinus linteus could be useful as an anti-wrinkle cosmetic ingredient.

• Journal of the Korean association of regional geographers
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• v.23 no.1
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• pp.106-117
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• 2017

Recently, urban regeneration is being actively promoted in Korea and among those Jeonju Hanok Village is the major project which is the most consistently promoted. For this, visitors of Jeonju Hanok Village are skyrocketing. However, due to this condition, various problems are occurring, especially about commercialization. In this regard, this study is to suggest management of the Jeonju Hanok Village and new orientation in the policy, by analyzing physical, economic, and social status due to urban regeneration for Jeonju Hanok Village which has lost its identity and been commercialized. For this, the study analyzed changes in land usage and real transaction price, SNS data. Firstly, in the physical analysis, the study realized that there is commercialization going around the main streets of Jeonju Hanok Village. Due to the rapid commercialization, living spaces for locals are replaced to commercial spaces for tourists, and the emigration of locals is caused by economic/environmental damages with the degradation of housing environments. Secondly, in the economic analysis, there was no gap in real transactions among streets in 2010 but has shown a valid gap in 2016. The traffic of tourists is heavy and the real transaction prices of streets that are adjacent to major tourist sights rose the most. Rising real transaction prices are a positive phenomenon in the aspect of the city regeneration but it is concerned that they can be perceived as investment subjects. Thirdly, in the social analysis, tourists are using commercial aspects more than historical or cultural sites, and have lots of interest on those. However, because there are also lots of opinions about the commercialization of Hanok Village, we think the plans which can establish the identity of Hanok Village should be prepared. The study has its meaning on analyzing reality based on the land usage, real transaction, SNS data and suggesting political implications.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.227-233
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• 2004

Chronic exposure to solar radiation, particularly ultraviolet (UV) light, causes a variety of adverse reactions on human skin, such as sunburn, photoaging and photocarcinogenesis. Free radicals and reactive oxygen species (ROS) caused by UV exposure or other environmental facts play critical roles in cellular damage. And, repeated-UV irradiation activated the expression of the matrix metalloproteinase (MMP) and induced skin irritation. Therefore, the development of effective and safe photoprotectants that can reduce and improve the skin damage has been required. The purpose of this study was to investigate the photo-protective effect of several chinese medical plants (Juniperus chinensis) on the UV -induced skin cell damages. We tested free radical and superoxide scavenging effect in vitro. Fluorometric assays of the proteolytic activities of MMP-1 (collagenase) were performed using fluorescent collagen substrates. UVA induced MMP-1 synthesis and activity were analyzed by enzyme-linked immunosorbent assay (ELISA) and gelatin-based zymography in skin fibroblasts. We also examined anti-inflammatory effects by the determination test of proinflammatory cytokine, interleukin 6 in HaCaT keratinocytes. Expression of prostaglandin E$_2$ (PGE$_2$) after UVB irradiation was measured by competitive enzyme immunoassay(EIA) using PGE$_2$ monoclonal antibody. In the human skin we tested anti-irritation effect on the SLS-induced damage skin after appling the extract containing emulsion. We found that Juniperus chinensis extract had potent radical scavenging effect by 98% at 100$\mu\textrm{g}$/mL. The extract of Juniperus chinensis showed strong inhibitory effect on MMP-1 activities by 97% at 100 $\mu\textrm{g}$/mL and suppressed the UVA induced expression of MMP-1 by 79% at 25$\mu\textrm{g}$/mL. This extract also showed strong inhibition on MMP-2 activity in UVA irradiated fibroblast by zymography. In the test of proinflammatory cytokines of human keratinocytes Juniperus chinensis extract decreased expression of interleukin 6 about 30%. The amount of PGE$_2$ by HaCaT keratinocytes was significantly increased at the doses of above 10 mJ/$\textrm{cm}^2$ of UVB (p < 0.05). At the concentrations of 3.2-25$\mu\textrm{g}$/mL of this extract, the production of PGE$_2$ by HaCaT keratinocytes (24 h after 10mJ/$\textrm{cm}^2$ UVB irradiation) was significantly inhibited in culture supernatants (p < 0.05). In SLS-induced skin irritation model in vivo, we found to reduce skin erythema and improve barrier recovery after appling Juniperus chinensis extract containing emulsion when compared to irritated non-treated and placebo-treated skin. Our results suggest that Juniperus chinensis extract can be effectively used for the prevention of UV and SLS-induced adverse skin reactions and applied as anti-aging and anti-irritation cosmetics.

• Journal of Korea Water Resources Association
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• v.53 no.9
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• pp.661-670
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• 2020

The water supply system has a wider installation range and various components of it than other infrastructure, making it difficult to secure stability against earthquakes. Therefore, it is necessary to develop methods for evaluating the seismic performance of water supply systems. Ground Motion Prediction Equation (GMPE) is used to evaluate the seismic performance (e.g, failure probability) for water supply facilities such as pump, water tank, and pipes. GMPE is calculated considering the independent variables such as the magnitude of the earthquake and the ground motion such as PGV (Peak Ground Velocity) and PGA (Peak Ground Acceleration). Since the large magnitude earthquake data has not accumulated much to date in Korea, this study tried to select a suitable GMPE for the domestic earthquake simulation by using the earthquake data measured in Korea. To this end, GMPE formula is calculated based on the existing domestic earthquake and presented the results. In the future, it is expected that the evaluation will be more appropriate if the determined GMPE is used when evaluating the seismic performance of domestic waterworks. Appropriate GMPE can be directly used to evaluate hydraulic seismic performance of water supply networks. In other words, it is possible to quantify the damage rate of a pipeline during an earthquake through linkage with the pipe failure probability model, and it is possible to derive more reasonable results when estimating the water outage or low-pressure area due to pipe damages. Finally, the quantifying result of the seismic performance can be used as a design criteria for preparing an optimal restoration plan and proactive seismic design of pipe networks to minimize the damage in the event of an earthquake.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.4
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• pp.232-242
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• 2002

To investigate the effects of arbuscular mycorrhizal (AM) fungus (Glomus intraradices) colonization on drought-stress tolerance, leaf water potential, chlorophyll concentration, P content and carbohydrate composition were examined in perennial ryegrass (Lolium perenne L.) plants exposed to drought-stressed or well-watered conditions. Drought stress significantly decreased leaf water potential, P content and leaf growth. These drought-induced damages were moderated by mycorrhizal colonization. Drought stress decreased the concentration of soluble sugars in shoots. AM plants had a higher foliar soluble sugar than non-AM plants under drought stress condition. Drought stress depressed the accumulation of starch and fructan in shoots, but stimulated in roots. Under drought-stressed condition, starch concentration in roots was higher in non-AM plants than in AM plants. Fructan was the largest pool of carbohydrates, showing the highest initial concentration and the highest net increase for 28 days of treatment. Drought stress slightly decreased fructan concentration in shoots, but remarkably increased in roots. Under drought-stressed condition, fructan concentrations in non-AM and AM shoots at day 28 were 18.7% and 13.3% lower than the corresponding values measured at well-watered plants. However, in the roots, fructan accumulation caused by drought was lessen 13.6% by mycorrhizal colonization. The results obtained suggest that mycorrhizal colonization improves drought tolerance of the host plants by maintaining higher leaf water status and P status, and by retaining more foliar soluble sugars.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.3
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• pp.158-169
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• 2019

A probabilistic model that can predict the residual useful lifetime of structure is formulated by using the gamma process which is one of the stochastic processes. The formulated stochastic model can take into account both the sampling uncertainty associated with damages measured up to now and the temporal uncertainty of cumulative damage over time. A method estimating several parameters of stochastic model is additionally proposed by introducing of the least square method and the method of moments, so that the age of a structure, the operational environment, and the evolution of damage with time can be considered. Some features related to the residual useful lifetime are firstly investigated into through the sensitivity analysis on parameters under a simple setting of single damage data measured at the current age. The stochastic model are then applied to the rubble-mound breakwater straightforwardly. The parameters of gamma process can be estimated for several experimental data on the damage processes of armor rocks of rubble-mound breakwater. The expected damage levels over time, which are numerically simulated with the estimated parameters, are in very good agreement with those from the flume testing. It has been found from various numerical calculations that the probabilities exceeding the failure limit are converged to the constraint that the model must be satisfied after lasting for a long time from now. Meanwhile, the expected residual useful lifetimes evaluated from the failure probabilities are seen to be different with respect to the behavior of damage history. As the coefficient of variation of cumulative damage is becoming large, in particular, it has been shown that the expected residual useful lifetimes have significant discrepancies from those of the deterministic regression model. This is mainly due to the effect of sampling and temporal uncertainties associated with damage, by which the first time to failure tends to be widely distributed. Therefore, the stochastic model presented in this paper for predicting the residual useful lifetime of structure can properly implement the probabilistic assessment on current damage state of structure as well as take account of the temporal uncertainty of future cumulative damage.