• International Journal of Concrete Structures and Materials
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• v.9 no.4
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• pp.487-498
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• 2015

A proper initial curing is a very simple and inexpensive alternative to improve concrete cover quality and accordingly extend the service life of reinforced concrete structures exposed to aggressive species. A current study investigates the effect of wet curing duration on chloride penetration in plain and blended cement concretes which subjected to tidal exposure condition in south of Iran for 5 years. The results show that wet curing extension preserves concrete against high rate of chloride penetration at early ages and decreases the difference between initial and long-term diffusion coefficients due to improvement of concrete cover quality. But, as the length of exposure period to marine environment increased the effects of initial wet curing became less pronounced. Furthermore, a relationship is developed between wet curing time and diffusion coefficient at early ages and the effect of curing length on time-to-corrosion initiation of concrete is addressed.

• Toxicological Research
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• v.20 no.1
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• pp.55-61
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• 2004

Respiratory effects in full time welders include bronchitis, airway irritation, lung function changes, and lung fibrosis. Welder's pneumoconiosis has been generally determined to be benign and not associated with respiratory symptoms based on the absence of pulmonary function abnormalities in welders with marked radiographic abnormalities. Accordingly, to investigate pulmonary function changes during 60 days induced by welding-fume exposure, male Sprague-Dawley rats were exposed to manual metal arc-stainless steel (MMA-SS) welding fumes with concentrations of 64.8$\pm$0.9 mg/$m^3$ (low dose) and 107.8 $\pm$ 2.6 mg/$m^3$ (high dose) total suspended particulates for 2 hr/day, 5 days/week in an inhalation chamber for 60 days. Pulmonary function was measured every week with whole body plethysmograph compensated (WBP Comp, SFT38116, Buxco Electronics, Sharon, CT). The rats exposed to the high dose of welding fumes exhibited statistically significant (p<0.05~0.01) body weight decrease as compared to the control whereas cell number increase of the bronchoalveolar lavage fluid (BALF) (total cell, macrophage, polymorphonuclear cell and lymphocyte) during the 60 days exposure period. And only tidal volume was significantly decreased in dosedependantly during 60 days of MMA-SS welding fume exposure. This pulmonary function change with inflammatory cell recruitment confirms the lung injury caused by the MMA-SS welding fume exposure.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.2
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• pp.99-106
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• 1993

A two-dimensional numerical analysis is performed for the simulation of intertidal-flat and analysis of hydraulic characteristics during seadike construction in Sae-Man-Keum tidal basin. The shallow water equations are selected as a mathematical model and the Leendertse's ADI scheme is used as the corresponding numerical model. The simulated results of tide and current by the present model agree welt with the experimenta1 results by the hydraulic Lab. or ADC (1989). In the application of the model, the possibility of rapidly varied flow analysis and the introduction of turbulence model required for more accurate hydraulic calculation at closing gap are described. The successive simulation of flooding/drying effects by a modification of the method by Stelling et al. (1986) can easily be used for the intertidal-flat analysis during tidal reclamation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.2
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• pp.55-62
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• 2000

In order to make the reasonable irrigation plan in the unripended tidal reclaimed paddy fields, the estimation of irrigation water requirements by soil textures and water management methods for the normal growth of crops is very important . This study was carried out to determine leaching requirements before cultivating crops. For the purpose of this study, the physical and chemical properties of soil samples used in the desalinization experiments were analyzed, and change of salinity by supplying water and leaching water were investigated in the experimental field with lysimeters. As a result considering the soil textures, desalinization effects of good drainage soils(S1) were better than those of poor drainage soils (S2). In the changes of salinity of the soils with supplying water by water management methods, among the good grainage soils with culvert treatment(S1CW), salinity of S1CW3 with 1, 120mm and S1W4 with 1, 440mm supplying water were 2.6dS/m and 1.1dS/m respectively, and salinity of S1NW4 with 1.680mm among those non-culvert treatment (S1NW) was 3.0dS/m, less than critical salanity value 3.0dS/m. On the other hand, of the poor drainage soils with cultvert treatment , salinity of S2CW3 was ranged 9.4-6.0dS/m with supplied water, and that of non-culverted treatment S2NW as 12.3-8.4dS/m.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.139-139
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• 2017

우리나라 수자원의 잠재적 문제점중 하나는 단일 하천 혹은 댐에 대한 의존도가 매우 높다는 것이다. 이러한 현상은 한반도의 지형, 기상, 경제성 등의 요인에 의해 야기된 결과이기도 하지만, 지하수 수자원의 불확실성과 적정 관리의 어려움에서 기인하였다. 지하수는 유속이 매우 느리며 눈에 보이지 않기 때문에 지하수 과잉개발 및 오염 등에 취약하다는 단점이 있는 것이 사실이다. 그러나 지하수자원을 활용하지 않고 무작정 보존하기 보다는 많은 연구개발을 통하여 지속가능한 수자원으로 활용하는 것이 더 바람직하다. 해안에 위치한 지하수개발관정의 경우 바닷물이 대수층을 통해 침투하여 지하수관정을 오염시키는 경우가 발생한다. 해안지하수의 주된 오염 원인은 과잉양수로 해수침투를 야기한 결과이다. 이러한 경우 수질을 회복하기까지 수년이 걸리게 되며, 그동안 취수원으로서의 가치를 상실하게 된다. 또한 최근에는 기후변화의 영향으로 해수면상승에 따른 해수침투길이가 길어져 기존의 해안지역 지하수의 오염위험성이 더욱 증가할 것으로 전망된다. 이러한 이유로 국내외에서 해안지하수 개발에 대한 많은 연구가 진행되고 있다. 많은 해안지하수 수치해석연구에서는 해안경계에 평균해수면(MSL)이 적용된다. 본 연구에서는 조위변화가 지하수위 및 해수침투에 끼치는 영향에 대해 연구하였다.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.31.2-31.2
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• 2020

Mass segregation, a tendency of more massive galaxies being distributed closer to the cluster center, is naturally expected from dynamical friction, but its presence is still controversial. Using deep optical observations of 14 Abell clusters (KYDISC) and a set of hydrodynamic simulations (YZiCS), we find in some cases a hint of mass segregation inside the virial radius. Segregation is visible more clearly when the massive galaxy fraction is used instead of mean stellar mass. The trend is more significant in the simulations than in the observations. To find out the mechanisms working on mass segregation, we look into the evolution of individual clusters simulated. We find that the degree of mass segregation is different for different clusters: the trend is visible only for low-mass clusters. We compare the masses of galaxies and their dark haloes at the time of infall and at the present epoch to quantify the amount of tidal stripping. We then conclude that satellites that get accreted at earlier epochs, or galaxies in more massive clusters go through more tidal stripping. These effects in combination result in a correlation between the host halo mass and the degree of stellar mass segregation. This is a work submitted to The Astrophysical Journal (under review).

• Journal of Chest Surgery
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• v.25 no.4
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• pp.391-397
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• 1992

Postoperative hypoxemia in the absence of hypoventilation occurs more often after thoracic or upper abdominal surgery than lower abdominal operations or surgery on extremities. Although the factors which produce postoperative alveolar collapse have not been fully evaluated, the dominant factor of postoperative hypoxia is shunt of blood passing collapsed alveoli and the postoperative pain is associated with restriction of depth of breathing, sighing and movement. In 1979, the first successful clinical usage of epidurally administered morphine was done by Behar and associates for control of postoperative pain. This study was carried out for twenty patients who received posterolateral thoracostomy with Bled resection between May 1990 and May 1991 and who were primary spontaneous recurrent pneumothoraxes. We selected ten of twenty patients, one after the other and treated with epidural analgesia as study group and the remainder ten were grouped as control. Epidural catheters were inserted for study group before operation through T12-L1, 2 interspinous process at the pain clinic or operation room by anesthesiogist and then the drugs[0.25% Bupivacaine 15ml mixing with morphine 3mg] were instillated through the catheter before extubarion and once a day until 4th day, and the patients of control group were treated intermittently by Demerol 50mg intramuscularly for postoperative pain control. The epidural catheters were removed at postoperative 4th day. Observations were done about vital aigns, a-BGA, tidal volume, FVC and occurence of adverse effects during postoperative 2hr, 8hr, 1st day, 2nd day, 7th day in both groups. The results were as follows; [1] Tidal volume[85.1$\pm$29.8%R VS 60.8$\pm$20.5%R, p<0.05] and FVC[53.7$\pm$14.2%R, VS 35.5$\pm$9.l%R, p<0.01] were significantly improved in study group compared with control group during the first day of operation. [2] But the improvement of FVC was delayed after stopping of epidural analgesia[postoperative 7th day, 97.5$\pm$12.3%R VS 83.9$\pm$15.6%R, P <0.05]. [3] Others were statistically not significant. [4] The side effects of epidural analgesia were identified such as urinary retention[2 cases], itching sensation[1 case] and headache[1 case], but there was no need for active treatments.

• Journal of Veterinary Clinics
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• v.23 no.4
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• pp.447-452
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• 2006

This study was performed to compare propofol, thiopental, etomidate and diazepam plus ketamin as induction agents for the isoflurane anesthesia in dogs. Experimental groups were divided into low groups (thiopental group: thiopental 15 mg/kg IV, propofol group: propofol mg/kg IV, etomidate group: etomidate 1.5 mg/kg IV, DZP+KET group: diazepam 0.5 mg/kg + ketamine 5 mg/kg, IV) and each group was consisted of 4 dogs. Cardiorespiratory changes (heart rate, $SpO_2$, respiratory rate, End-tidal $CO_2$ and body temperature), blood serum chemistry values (alkaline phosphatase, alanine aminotransforase, and total protein), and recovery and walking time were measured. The end tidal carbon dioxide level was significantly increased in the thiopental group (P<0.05). Heart rate and respiratory rate higher in the DZP+KET groups. There was hypothermia in all groups and significant decrease in body temperature was showed in thiopental group (p<0.05). Mean arousal time and mean walking time were significantly longer in thiopental group (P<0.05). Cardiovascular stimulating effects were minimal in etomidate group. Etomidate provides uneventful and rapid recovery.

• Korean Journal of Agricultural Science
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• v.32 no.2
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• pp.107-126
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• 2005

The most limited production resource in Korea is land. During the period from 1995 to 2002, annual farm land area of 17,600ha have been converted to urban and industrial land. The self-sufficiency rate of rice, Korean staple food, is expected to be decreased from 97.5% in 2003 to 60-70% in 2020. Under such conditions, this study is aimed at first identifying multi-functional benefits of the reclamation projects such as agricultural production, industrial water supply, urban land supply, transportation effects, sightseeing effects and environmental values with and without the projects. To carry out the objectives, three existing tideland reclamation projects such as Daeho, Kumgang and Yongsangang irrigation project stage II were evaluated and Saemangeum tideland reclamation project which was jointly revaluated by environmental NGO and Govn't appointed specialists in 2000 was reviewed. According to this study results, tide land reclamation projects were showed financially and economically feasible and environmentally sustainable. The joint cost like estuary dam should be allocated based on the multi-functional benefits of the projects. To allocate the joint cost, legal and institutional improvement should adapt the joint cost allocation method as the specific cost-remaining benefit method. Korea has more than 402,000 ha of tidal flat of which 76,396ha have been reclaimed in 2003. To meet food security and to cope with shortage of land, phil-environmental reclamation projects should be continuously implemented and necessary tidal flats for protecting environmental ecosystem should be remained according to the detail survey results of reclaimable resources.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.45.2-45.2
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• 2017

Using the latest cosmological hydrodynamic N-body simulations of groups and clusters, we study how location in phase-space coordinates at z = 0 can provide information on environmental effects acting in clusters. We confirm the results of previous authors showing that galaxies tend to follow a typical path in phase-space as they settle into the cluster potential. As such, different regions of phase-space can be associated with different times since first infalling into the cluster. However, in addition, we see a clear trend between total mass loss due to cluster tides and time since infall. Thus, we find location in phase-space provides information on both infall time and tidal mass loss. We find the predictive power of phase-space diagrams remains even when projected quantities are used (i.e.,line of sight velocities, and projected distances from the cluster). We provide figures that can be directly compared with observed samples of cluster galaxies and we also provide the data used to make them as supplementary data to encourage the use of phase-space diagrams as a tool to understand cluster environmental effects. We find that our results depend very weakly on galaxy mass or host mass, so the predictions in our phase-space diagrams can be applied to groups or clusters alike, or to galaxy populations from dwarfs up to giants.