• Wind and Structures
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• v.25 no.2
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• pp.101-129
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• 2017

Local transient extreme wind loads caused by group tower-related interference are among the major reasons that lead to wind-induced damage of super-large cooling towers. Four-tower arrangements are the most commonly seen patterns for super-large cooling towers. We considered five typical four-tower arrangements in engineering practice, namely, single row, rectangular, rhombic, L-shaped, and oblique L-shaped. Wind tunnel tests for rigid body were performed to determine the influence of different arrangements on static and dynamic wind loads and extreme interference effect. The most unfavorable working conditions (i.e., the largest overall wind loads) were determined based on the overall aerodynamic coefficient under different four-tower arrangements. Then we calculated the one-, two- and three-dimensional aerodynamic loads under different four-tower arrangements. Statistical analyses were performed on the wind pressure signals in the amplitude and time domains under the most unfavorable working conditions. On this basis, the non-Gaussian distribution characteristics of aerodynamic loads on the surface of the cooling towers under different four-tower arrangements were analyzed. We applied the Sadek-Simiu procedure to the calculation of two- and three-dimensional aerodynamic loads in the cooling towers under the four-tower arrangements, and the extreme wind load distribution patterns under the most unfavorable working conditions in each arrangement were compared. Finally, we proposed a uniform equation for fitting the extreme wind loads under the four-tower arrangements; the accuracy and reliability of the equation were verified. Our research findings will contribute to the optimization of the four-tower arrangements and the determination of extreme wind loads of super-large cooling towers.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.4
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• pp.913-921
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• 2005

In this study, we investigated gene expression patterns induced by Ailanthus altissima extract and compared it with Gleevec, a well-known anti-leukemia drug, in K562 chromic leukemia cells. Ailanthus altissima extract(100 ug/ml) and Gleevec(50 ug/ml) were treated to cells for 1h, 2h, 4h, and 16h and total RNA was extracted. Gene expressions were evaluated using cDMA microarray, in which 24,000 genes were spotted. Hierarchical clustering analysis showed that expression of genes included in two clusters were increased or decreased time dependently by both Ailanthus altissima extract and Gleevec. Genes included in another cluster were induced by Ailanthus altissima extract but not by Gleevec. In biological process analysis, expression of genes involved in apoptosis, growth arrest and DNA-damage were increased, but genes stimulating cell cycle were decreased. This study provides comprehensive comparison of the patterns of gene expression changes induced by Ailanthus altissima extract and Gleevec in K-562 leukemia cells.

• Korean Journal of Veterinary Service
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• v.40 no.2
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• pp.101-105
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• 2017

The purpose of this study was to investigate prevalence and antimicrobial resistance patterns of Campylobacter spp. from duck feces in northern area of the Gyeongnam province, Korea. Samples of 121 duck feces were taken from April to December 2014 for this survey. Samples were examined by bacteria isolation and reverse transcriptase-polymerase chain reaction assay for detection of Campylobacter spp. Campylobacter were isolated in 37 samples (30.6%). Among these samples, C. jejuni and C. coli were isolated in 35 samples and 2 samples, respectively. Minimum inhibitory concentration (MIC) test is performed to investigate antimicrobial resistance patterns of Campylobacter spp. C. jejuni were resistant to ciprofloxacin (85.7%), nalidixic acid(82.9%), tetracycline (77.1%), gentamicin (57.1%), azithromycin (40.0%), clindamycin (34.3%), erythromycin (22.9%), and florfenicol (8.6%). These data support a database of pollution and antimicrobial resistance of Campylobacter spp. from duck feces and provide a basic information of reducing the secondary damage of antibiotic misuse.

• Journal of Korean Society of Forest Science
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• v.98 no.5
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• pp.593-601
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• 2009

Forest disturbances including forest fire, insect pests and diseases, landslides, and forest conversion from 1976 to 2005 were investigated to trace the changes of major forest disturbance agents and their characteristics over time in accordance with changes in natural and social environment in South Korea. While the damaged area by insect pests and diseases continuously decreased for the past 30 years, damaged areas by forest fire and landslide were fluctuating through years. The interval of large forest fires has become shorter with increased tree volume. The precipitation between January and April were significantly correlated with large fire occurrences as Pearson's correlation coefficient -0.400 (P=0.029). The composition of major insect pests and diseases damaging Korean forests has been changed continuously, and become more diversified. While damages by pine caterpillar (Dendrolimus spectabilis) and pine needle gall midge (Thecodiplosis japonensis) decreased, damage by introduced pests has been more serious recently. The change of precipitation pattern that brought more localized heavy rain or powerful typhoon resulted in the recent increase in landslide areas. The major land uses to induce forest conversion have been changed, reflecting the changes in industrial structure in South Korea as agriculture and mining in 1970s, mining and golf ranges classified in pasture in 1980s, and road and housing construction in 1990s and 2000s. Changes in forest disturbance patterns in South Korea show that a country's industrial development is jointly working with global warming on forest stand dynamics. Altering energy structure and land use pattern induced by industrial development accumulates forest volume and reforms microenvironments on forest floor, interacting with climate change, inducing shorter interval of large forest fire and changes in major species composition of forest insect pests and diseases.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.3
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• pp.400-406
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• 2014

Apios (Apios americana Medikus) belongs to Leguminosae and is called 'American groundnut', 'Potato bean', and 'wild bean'. Apios is native to the Northern United States but is not widely distributed in Korea. In this study, cross-linked apios starch was prepared by reaction with epichlorohydrin, followed by characterization. FT-IR spectroscopy confirmed the degree of cross-linking of apios starch. X-ray diffraction patterns of native apios showed typical 'A' type as peaks at 15.1, 17.1, 17.9 and $23.2^{\circ}$, and cross-linking did not affect relative crystallinity and X-ray diffraction patterns of the starch. Scanning electron micrographs showed that apios starch granules were smooth with a globular shape, and there was little damage to starch granules after cross-linking. The lightness value of cross-linked apios starch was lower than that of native apios starch, whereas the redness value was not significantly different between cross-linked apios starch and native apios starch. Blue value showed that cross-linking of starch did not affect the iodine reaction of starch.

• Journal of the Korean Institute of Gas
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• v.4 no.3 s.11
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• pp.19-25
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• 2000

In order to prevent secondary disaster such as gas explosion which comes after a devastating magnitude earthquake, the seismic monitoring and transmission system for natural gas governor station was developed. To measure ground motions precisely and operate the seismic monitoring system efficiently, the position and method of accelerometer installation were recommended by the analysis of ground noise patterns of governor station. For making a decision on prompt shut-off of gas supplies in the event of a great earthquake, the real-time calculation algorithm of PGA(Peak Ground Acceleration) and SI(Spectrum Intensity) were developed and it has been implemented in the seismic monitoring and transmission system.

• Earthquakes and Structures
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• v.18 no.6
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• pp.691-707
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• 2020

One of the most important issues in structural systems is evaluation of the margin of safety in low and mid-rise buildings against the progressive collapse mechanism due to the earthquake loads. In this paper, modeling of collapse propagation in structural elements of RC frame buildings is evaluated by tracing down the collapse points in beam and column structural elements, one after another, under earthquake loads and the influence of column removal is investigated on how the collapse expansion in beam and column structural members. For this reason, progressive collapse phenomenon is studied in 3-story and 5-story intermediate moment resisting frame buildings due to the corner and edge column removal in presence of the earthquake loads. In this way, distribution and propagation of the collapse in progressive collapse mechanism is studied, from the first element of the structure to the collapse of a large part of the building with investigating and comparing the results of nonlinear time history analyses (NLTHA) in presence of two-component accelograms proposed by FEMA_P695. Evaluation of the results, including the statistical survey of the number and sequence of the collapsed points in process of the collapse distribution in structural system, show that the progressive collapse distribution are special and similar in low-rise and mid-rise RC buildings due to the simultaneous effects of the column removal and the earthquake loads and various patterns of the progressive collapse distribution are proposed and presented to predict the collapse propagation in structural elements of similar buildings. So, the results of collapse distribution patterns and comparing the values of collapse can be utilized to provide practical methods in codes and guidelines to enhance the structural resistance against the progressive collapse mechanism and eventually, the value of damage can be controlled and minimized in similar buildings.

• Composites Research
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• v.34 no.4
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• pp.226-232
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• 2021

In this paper, development of tape-springs made of composite materials was conducted for the deployment structures along with design, analysis, fabrication, and numerical and experimental investigation of mechanical behavior of the tape-springs. To this end, the tape-springs were manufactured according to three stacking patterns, and numerical and experimental investigation were conducted to determine whether or not they were damaged during bending with various selected composite materials. Finally, optimal stacking patterns that do not cause damage were selected during bending. With this information, the four-point bending test was conducted to obtain the moment-rotation curves. From results, it was confirmed that the nonlinear hysteresis phenomenon of the tape-springs was properly realized according to folding and unfolding. Therefore, it was confirmed that the composite material tape spring was properly developed.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.208-208
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• 2022

Recently, the frequency of abnormal weather due to complex factors such as global warming is increasing frequently. From the past rainfall patterns, it is evident that climate change is causing irregular rainfall patterns. This phenomenon causes difficulty in predicting rainfall and makes it difficult to prevent and cope with natural disasters, casuing human and property damages. Therefore, accurate rainfall estimation and rainfall occurrence time prediction could be one of the ways to prevent and mitigate damage caused by flood and drought disasters. However, rainfall prediction has a lot of uncertainty, so it is necessary to understand and reduce this uncertainty. In addition, when accurate rainfall prediction is applied to the rainfall-runoff model, the accuracy of the runoff prediction can be improved. In this regard, this study aims to increase the reliability of rainfall prediction by analyzing the uncertainty of the Korean rainfall ensemble prediction data and the outflow analysis model using the Limited Area ENsemble (LENS) and the Grid based Rainfall-runoff Model (GRM) models. First, the possibility of improving rainfall prediction ability is reviewed using the QM (Quantile Mapping) technique among the bias correction techniques. Then, the GRM parameter calibration was performed twice, and the likelihood-parameter applicability evaluation and uncertainty analysis were performed using R², NSE, PBIAS, and Log-normal. The rainfall prediction data were applied to the rainfall-runoff model and evaluated before and after calibration. It is expected that more reliable flood prediction will be possible by reducing uncertainty in rainfall ensemble data when applying to the runoff model in selecting behavioral models for user uncertainty analysis. Also, it can be used as a basis of flood prediction research by integrating other parameters such as geological characteristics and rainfall events.

• Anatomy and Cell Biology
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• v.56 no.2
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• pp.228-235
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• 2023

Toll-like receptors (TLRs) are the mammalian ortholog of Drosophila melanogaster protein Toll, originally identified for its involvement in embryonic development. In mammals, TLRs are mainly known for their ability to recognize pathogen- or damage-associated molecular patterns and, consequently, to initiate the immune response. However, it is becoming clear that TLRs can play a role also in mammal embryo development. We have previously described TLR4 and TLR7 expression in developing mouse peripheral nervous system and gastrointestinal tract. In the present study, we extended the investigation of TLR4 and TLR7 to the respiratory system and to the two main accessory organs of the digestive system, the liver and pancreas. TLR4 and TLR7 immunostaining was performed on mouse conceptuses collected at different stages, from E12 to E18. TLR4 and TLR7 immunoreactivity was evident in the embryo pancreas and liver at E12, while, in the respiratory apparatus, appeared at E14 and E17, respectively. Although further studies are required to elucidate the specific role of these TLRs in embryo development, the differential spatiotemporal TLR4 and TLR7 appearance may suggest that TLR expression in developing embryos is highly regulated for a possible their direct involvement in the formation of the organs and in the acquisition of immune-related features in preparation for the birth.