• Structural Engineering and Mechanics
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• v.38 no.1
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• pp.99-123
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• 2011

Brick veneer over steel stud backup wall is lighter and easier to construct compared to brick veneer over concrete masonry backup wall. However, due to the relatively low stiffness of the steel stud backup, the brick veneer tends to crack under wind load. This paper briefly introduces a new panelized brick veneer with steel frame backup wall system that is developed to potentially address this problem. The experimental study of the performance of this system under simulated wind loading is discussed in detail. The test setup details and the test specimens are introduced, results of major interests are presented, and performance of the new system is evaluated based on the test results.

• Atmosphere
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• v.17 no.4
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• pp.435-453
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• 2007

KEOP (Korea Enhanced Observing Period)-2004 intensive summer observation was carried out from 20 June to 5 July 2004 over the Southwestern part of the Korean peninsula. In this study, the effects of KEOP-2004 intensive observation data on the simulation of precipitation system are investigated using KLAPS (Korea Local Analysis and Prediction System) and PSU/NCAR MM5. Three precipitation cases during the intensive observation are selected for detailed analysis. In addition to the control experiments using the traditional data for its initial and boundary conditions, two sensitivity experiments using KEOP data with and without Jindo radar are performed. Although it is hard to find a clear and consistent improvement in the verification score (threat score), it is found that the KEOP data play a role in improving the position and intensity of the simulated precipitation system. The experiments started at 00 and 12 UTC show more positive effect than those of 06 and 18 UTC. The effect of Jindo radar is dependent on the case. It plays a significant role in the heavy rain cases related to a mesoscale low over Changma front and the landing of a Typhoon. KEOP data produce more strong difference in the 06/18 UTC experiments than in 00/12 UTC, but give more positive effects in 00/12 UTC experiments. One of the possible explanations for this is that : KEOP data could properly correct the atmosphere around them when there are certain amounts of data, while gives excessive effect to the atmospheric field when there are few data. CRA analysis supports this reasoning. According to the CRA (Contiguous Rain Area) analysis, KEOP data in 00/12 UTC experiments improve only the surrounding area, resulting in essentially same precipitation system so the effects remain only in each convective cell rather than the system itself. On the other hand, KEOP data modify the precipitation system itself in 06/18 UTC experiments. Therefore the effects become amplified with time integration.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.6
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• pp.556-563
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• 1994

To compare the tolerance of crops to acid rain of simulated acid rains(SAR) of three pH levels (3.0, 4.5, and 6.0) were applied to rice, corn, soybean, adzuki bean, hot pepper, tomato, sesame, barley, wheat, Chinese cabbage, radish, lettuce, and spinach for 30 days from 20 days after emergence at two-day interval with 10mm at a time. No visual damages were observed. Also, no alteration of ultrastructure was observed although some lightly stained lipid granules were observed in the chloroplasts of sesame, soybean, and adzuki bean at the SAR treatment of pH 3.0. As pH of SAR decreased, chlorophyll content increased in adzuki bean, decreased in rice, tomato, and spinach, and similar in the other crops. Photosynthetic activity of adzuki bean increased, while decreased in Chinese cabbage and barley as pH of SAR decreased, and similar in other crops. Concentration and uptake of N were not affected by SAR treatments in all crops except tomato and barley. When a strong SAR of pH 2.0 was applied, rice, corn, sesame, tomato, barley, and wheat were relatively tolerant, while adzuki bean, hot pepper, soybean, Chinese cabbage, lettuce, radish, and spinach were susceptible in terms of visual damages.

• Korean Journal of Environmental Agriculture
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• v.17 no.4
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• pp.362-367
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• 1998

To investigate the effects of simulated acid rain(SAR) on the downward movement of mineral nutrients, SARs of different pH were applied to the soil. SAR of pH 2.0 decreased the soil pH greatly, while SAR of pH 4.0 and 6.0 did not change the soil pH to compare to that of SAR of pH 2.0. Decrease in soil pH was in the order of sandy loam > loam > clay loam. The amoumt of leached exchangeable and soluble bases from the soil due to the penetration of SAR was in the order of Ca >Mg > K. After application of 1200mm SAR of pH 2.0 in to the soil downward mean movements of the exchangeable and soluble bases was in the order of Mg > Ca > K in sandy loam and loam soil and Ca > Mg > K in clay loam soil. Downward movements of the those bases under pH 4.0 into the soil was in the order of Mg > K > Ca in sandy loam and clay loam, and K > Mg > Ca in loam soil. Available phosphorus moved slightly downward with increasing acidity of the SAR.

• Korean Journal Plant Pathology
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• v.11 no.3
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• pp.210-216
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• 1995

Alternaria spp.were predominantly isolated from the abnormal leaf spot lesions of pear cultivars Niitaka and Nijiiseiki. Alternaria isolates from the cultivar Niitaka were not pathogenic to both cultivars, but the isolates from the cultivar Nijiiseiki developed typical lesions of black leaf spots and were identified as A. kikuchiana. However, no typical abnormal leaf spot lesions were produced by the Alternaria isolates. Foliar spray of twelve different agrochemicals including lime sulfur, either alone or in combinations, with 7 times applications from April to July failed to reduced the disease development. Application of 17 different pesticides including fungicides, insecticides and herbicides currently used in pear orchards did not cause leaf injury similar to the abnormal leaf spot. Simulated acid rain of as low as pH 3.0 did not incite any leaf lesions alike the abnormal spot lesions. Mineral contents in the leaves of both cultivars did not differ significantly between the healthy leaves and those with abnormal leaf spots. When cuttings of pear tree were obtained in February from newly emerged twigs of the healthy or the diseased trees of Niitaka and planted in sand in the greenhouse, only those from the diseased trees developed typical leaf lesions of the abnormal spot. These results indicate that abnormal leaf spots are caused by unknown systemic agents in pear trees, rather than by Alternaria spp., chemical injury or acid rain.

• Atmosphere
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• v.25 no.2
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• pp.283-294
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• 2015

For urban flash flood simulation, we need the higher resolution radar rainfall than radar rainfall of KMA, which has 10 min time and 1km spatial resolution, because the area of subbasins is almost below $1km^2$. Moreover, we have to secure the high quantitative accuracy for considering the urban hydrological model that is sensitive to rainfall input. In this study, we developed the quantitative precipitation estimation (QPE), which has 250 m spatial resolution and high accuracy using KMA AWS and SK Planet stations with Mt. Gwangdeok radar data in Seoul area. As the results, the rainfall field using KMA AWS (QPE1) is showed high smoothing effect and the rainfall field using Mt. Gwangdeok radar is lower estimated than other rainfall fields. The rainfall field using KMA AWS and SK Planet (QPE2) and conditional merged rainfall field (QPE4) has high quantitative accuracy. In addition, they have small smoothed area and well displayed the spatial variation of rainfall distribution. In particular, the quantitative accuracy of QPE4 is slightly less than QPE2, but it has been simulated well the non-homogeneity of the spatial distribution of rainfall.

• Journal of Korean Society for Geospatial Information Science
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• v.25 no.2
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• pp.49-56
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• 2017

In this study, flood analysis was conducted to prepare for damage caused by typhoons and heavy rain due to abnormal climate and climate change. Two - dimensional flooding analysis using the FLUMEN model, which is widely used for national and international flood risk mapping, was conducted for the Nam River Basin, which is the tributary of the Nakdong River. This study divides the topography into $5m{\times}5m$ DEM by ArcView, so that the accuracy of river repair and hydrological characterization and flood area identification can be maximized. As a result of simulation of water flooding, 163.3ha in section 1, 227.7ha in section 2 and 59.9ha in section 3 were simulated.

• Atmosphere
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• v.22 no.4
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• pp.387-400
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• 2012

This study aims at examining the sensitivity of numerical simulations to the resolution of initial and boundary data, and to an application of WRF (Weather Research and Forecasting) 3DVAR (Three Dimension Variational data Assimilation). To do this, we ran the WRF model by using GDAS (Global Data Assimilation System) FNL (Final analyses) and the KLAPS (Korea Local Analysis and Prediction System) analyses as the WRF's initial and boundary data, and by using an initial field made by assimilating the radar data to the KLAPS analyses. For the sensitivity experiment, we selected a heavy rainfall case of 21 September 2010, where there was localized torrential rain, which was recorded as 259.5 mm precipitation in a day at Seoul. The result of the simulation using the FNL as initial and boundary data (FNL exp) showed that the localized heavy rainfall area was not accurately simulated and that the simulated amount of precipitation was about 4% of the observed accumulated precipitation. That of the simulation using KLAPS analyses as initial and boundary data (KLAPC exp) showed that the localized heavy rainfall area was simulated on the northern area of Seoul-Gyeonggi area, which renders rather difference in location, and that the simulated amount was underestimated as about 6.4% of the precipitation. Finally, that of the simulation using an initial field made by assimilating the radar data to the KLAPS using 3DVAR system (KLAP3D exp) showed that the localized heavy rainfall area was located properly on Seoul-Gyeonggi area, but still the amount itself was underestimated as about 29% of the precipitation. Even though KLAP3D exp still showed an underestimation in the precipitation, it showed the best result among them. Even if it is difficult to generalize the effect of data assimilation by one case, this study showed that the radar data assimilation can somewhat improve the accuracy of the simulated precipitation.

• Journal of Plant Biology
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• v.37 no.3
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• pp.309-316
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• 1994

To make regional comparisons of water status of pitch pine, the temporal changes of water status in pitch pine were investigated at different areas; urban Seoul (heavily polluted area), surburb of Seoul (lightly polluted area), and rural area (control). The effects of air pollutants, acid rain and chemical properties of soil on water deficit in pitch pine were also investiaged. Water content of needles growing at polluted areas were usually lower than that at unpolluted area. Water saturation deficit of needles growing at polluted areas were usually higher than that at unpolluted area especially in dry season. These results indicated that water in needles growing at polluted areas were usually more deficient than that at unpolluted area, and were more deficient in April than other months. At polluted areas, the older the needles were, the more quickly transpirated the water in the needle was. At unpolluted areas, however, water in old needles was not so quickly transpirated as those at polluted areas. Water potential of needles of pitch pine seedlings treated with simulated acid rain (SAR) of pH 3.5 decreased more quickly than that of needles treated with SAR of pH 5.6. Loss of water through epicuticular layer was greater in the following order: magnesium deficiency＋100 $\mu$M aluminium>100$\mu$M aluminium>magnesium deficiency>control. In addition to Mg deficiency and Al toxicity, growth decline of pitch pine widely occurring in polluated Seoul could to a large extent be due to cuticle degredation and abnormal vertical distribution of fine roots, which lead to water stress, particularly in dry seasons.

• Applied Science and Convergence Technology
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• v.26 no.6
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• pp.218-222
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• 2017

This study was conducted to remove $NO_x$, which is the main cause of fine dust and air pollution as well as acid rain. $NO_x$ was tested using 3% NO (diluted in He) as a simulated gas. Experiments were sequentially carried out by oxidizing NO to $NO_2$ and absorbing $NO_2$. Especially, we focused on the changes of NO oxidation according to both oxidant ($NaClO_2$) concentration change (1~10 M) and oxidant pH change (pH = 1~5) by adding HCl. In addition, we tried to suggest a method to improve $NO_2$ absorption by conducting $NO_2$ reduction reaction with reducing agent (NaOH) concentration (40~60%). It was found that NO removal efficiency increased as both concentration of oxidant and flow rate of NO gas increased, and NO decreased more effectively as the pH of hydrochloric acid added to the oxidant was lower. The $NO_2$ adsorption was also better with increasing NaOH concentration, but the NO removal efficiency was ~20% lower than that of the selective NO reduction. Indeed, this experimental method is expected to be a new method that can be applied to the capture and removal of fine dust caused by air pollution because it is a method that can easily remove NO gas by a simple device without expensive giant equipment.