• Fire Science and Engineering
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• v.30 no.4
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• pp.103-110
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• 2016

While the demand for the gas system fire extinguishers increases every year, there are insufficient safety measures for assessing the extinguishing performance, such as system safety and reliability in the preparation of increasing demand, which has emerged as a social problem. One of the most critical causes of accidents occurring with the gas extinguishing system is pressure leakage from the extinguishing agent storage container. This is considered to be one of the critical factors on which the success of fire suppression depends. In this study, its safety measure was studied, Because it was deemed urgently necessary. The newly developed pressure leakage monitoring system is a system monitoring storage condition, pressure, leakage and discharge of the storage container related to agent concentration, which is one of the critical factors for fire suppression. This was developed to be applicable to the $CO_2$ and HFC-23 systems. Therefore, for structural safety analysis, the safety performance was verified by the fluid structure coupling analysis of the safety problems that may occur when the pressure leakage monitoring system is applied to the gas fire extinguisher. For analysis programs, the FloEFD program from Mentor Graphics was used for computational fluid dynamics analysis and ABAQUS from Dassault Systems was used for structural analysis. From the result of numerical analysis, the structure of $CO_2$ did not develop plastic deformation and its safety was verified. However, plastic deformation and deviation issue occurred with the HFC-23 monitoring system and therefore verified the structural safety of pressure leakage monitoring system by data obtained from redesigning and adjusting the condition of numerical interpretation three times.

• The Journal of Engineering Geology
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• v.9 no.2
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• pp.147-159
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• 1999

Geostatistical methods were used for the groundwater flow analysis in a heterogeneous anisotropic aquifer. This study area is located at Sonbul-myeon in Hampyong-gun of Cheonnam Province which is a hydrogeological project area of KORES(Korea Resources Cooperation). Linear regression analysis shows that the topographic elevation and groundwater level of this area have very high correlation. Groundwater-level contour maps produced by ordinary kriging and cokringing have large differences in mountain areas, but small differences in hill and plain areas near the West Sea. Comparing two maps on the basis of an elevation contour map, a groundwater-level contour map using cokriging is more accurate. Analyzing the groundwater flow on two groundwater-level contour maps, the groundwater of study area flows from the high mountain areas to the plain areas near the West Sea. To verify the enffectiveness of geostatistical methods for the groundwater flow analysis in a heterogeneous anisotropic aquifer, the flow directions of groundwater were measured at two groundwater boreholes by a groundwater flowmeter system(model 200 $GeoFlo^{R}$). The measured flow directions of groundwater almost accord with those estimated on two groundwater-level contour maps produced by geostatistical methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.310-316
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• 2019

In automotive application, customers are demanding high efficiency and various functions for convenience. The demand for these automotive applications is steadily increasing. In this study, it has been studied the analysis of heat flow to improve the PCB(printed circuit board) heating performance of WPC (wireless power charger) recently developed for convenience. The charging performance of the wireless charger has been reduced due to power dissipation and thermal resistance of PCB. Therefore, it has been proposed optimal PCB design, layout and position of electronic parts through the simulation of heat flow analysis and PCB design was analyzed and decided at each design stage. Then, the experimental test is performed to verify the consistency of the analysis results under actual environmental conditions. In this paper, The PCB modeling and heat flow simulation in transient response were performed using HyperLynx Thermal and FloTHERM. In addition, the measurement was performed using infrared thermal imaging camera and used to verify the analysis results. In the final comparison, the error between analysis and experiment was found to be less than 10 % and the heating performance of PCB was also improved.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3144-3149
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• 2007

A numerical analysis for temperature distribution of four different materials such as iron, silicon, aluminum and PVC has been performed in this study to predict thermal behaviors of combined weapon systems in a large environmental tester. Thus, experimental conditions have been proposed using a calculating software (SolidWorks 2007 COSMOS FloWorks) to prepare for field tests and analyze heat flow inside the environmental tester and temperature distributions of materials. The boundary conditions of the analysis are composed of inlet and outlet conditions of the environmental tester with different pressures and the limit of low temperature of -30$^{\circ}C$. The soaking time of the system in the environmental tester has been calculated by this commercial program in this study to carry out the experiment.

• The Plant Pathology Journal
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• v.27 no.4
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• pp.301-309
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• 2011

The filamentous fungus Fusarium graminearum is an important cereal pathogen. Although quantitative realtime PCR (qRT-PCR) is commonly used to analyze the expression of important fungal genes, no detailed validation of reference genes for the normalization of qRT-PCR data has been performed in this fungus. Here, we evaluated 15 candidate genes as references, including those previously described as housekeeping genes and those selected from the whole transcriptome sequencing data. By a combination of three statistical algorithms (BestKeeper, geNorm, and NormFinder), the variation in the expression of these genes was assessed under different culture conditions that favored mycelial growth, sexual development, and trichothecene mycotoxin production. When favoring mycelial growth, GzFLO and GzUBH expression were most stable in complete medium. Both EF1A and GzRPS16 expression were relatively stable under all conditions on carrot agar, including mycelial growth and the subsequent perithecial induction stage. These two genes were also most stable during trichothecene production. For the combined data set, GzUBH and EF1A were selected as the most stable. Thus, these genes are suitable reference genes for accurate normalization of qRT-PCR data for gene expression analyses of F. graminearum and other related fungi.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.183-188
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• 2005

레이더강우관측의 수문학적 적용성을 검토하고 개념적 유출모형과 분포형 유출모형에서 지점강수 및 레이더강수를 적용하여 매개변수의 민감도 및 수문곡선변화를 관찰하였다. 레이더강수의 계통적오차는 총강수량비를 이용하여 보정하였고, 이결과 레이더강수가 지점강수에 비하여 첨두강수를 더욱 양호하게 표현하고 있음을 확인할 수 있었다. 지점강수와 레이더강수를 이용하여 용담댐 상류유역에 대한 유출해석을 수행하였다. 개념적모형으로는 저류함수모형을, 분포형모형으로는 실시간 홍수 조절을 목적으로 미국 Oklahoma대학에서 개발된 $V\;flo^{TM}$모형을 이용하여 테스트하였다. 결과 개념적 모형과 분포형모형 모두에서 경험식으로부터 구한 매개변수의 초기값을 이용한 수문곡선은 관측수문 곡선과 상당한 차이를 보이고 있었으나 분포형 수문곡선의 경우 천천상류지점의 수문곡선은 매개변수의 추가적 보정이 필요없을 정도로 매개변수의 초기값이 수문곡선을 잘 모의 하고 있었다. 이는 매우 고무적인 결과로서 실시간 홍수모형으로서 요구되는 중요한 특성과 동시에 물리적 기반의 분포모형의 가장 큰 장점일 수 있는 사상독립적 유역매개변수군을 구축하는데 중요한 단서가 될 것으로 보여진다.

• Journal of the Korean Society of Safety
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• v.31 no.2
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• pp.49-56
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• 2016

In Korea, there exist many mountains, and sudden storms occur during the summer season. When severe rainstorm events occur in steep slope topography, risk of debris flow is increased. Once debris flow occurs in urban area, it may cause casualties and physical damages due to rapid debris flow velocity along a steep slope. Accordingly, preventing method of sediment-related disaster for demage mitigation are essential. Recently, various studies on debris flow have been conducted. However, the prediction of the physical propagation of debris flow along the steep slope was not thoroughly investigated. Debris flow is characterized by various factors such as topography, properties of debris flow, amount of debris flow. In the study the numerical simulation was focused on the topographic factor. Fundamental analysis of the risk area was implemented with emphasis on the propagation length, thickness, and the development of maximum velocity. The proposed results and the methodology of estimating the structural vulnerability would be helpful in predicting the behavior and the risk assessment of debris flow in urban area. These results will be able to estimate the vulnerability of urban areas affected the most damage by debris flow.

• Phonetics and Speech Sciences
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• v.5 no.4
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• pp.71-78
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• 2013

The purpose of this study was to compare the acoustic voice outcomes of children with cochlear implant to those of children with normal hearing. Participants were 41 children using unilateral cochlear implant (18 males and 23 females), and children with normal hearing from the same age and sex. Mean age of implantation was approximately 3 years old, mean duration of implant use was 4 years in CI group. Acoustic analyses were performed using MDVP of CSL. Speech samples were 3 sustained vowels, /a, i, u/. 9 parameters (F0, Fhi, Flo, Jitter, Shimmer, vF0, vAm, NHR, and SPI) were analyzed. Children with CI did not show the significant differences in those parameters after the vowel /a/ phonation. Meanwhile, there were significantly different results in F0, Fhi, vF0, and SPI after /i, u/ phonation. These results revealed that differences of voice characteristics in children with CI compare to children with NH persist regarding vowel context. It suggests that high vowels would recommend as speech samples for acoustic evaluation. Futhermore perceptual analysis and speech therapy for phonation control would be necessary for children with CI.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.9
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• pp.979-982
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• 2004

The ZnO thin films were prepared by the FTS (facing target sputtering) system, which enables to provide high density plasma and a high deposition rate at a low working gas pressure. We introduced the AZO thin film in order to improve the crystallographic properties of ZnO thin film because of the AZO(ZnO:Al) thin film has an equal crystal structure to the ZnO thin film. ZnO/AZO thin films were deposited at a different oxygen gas flow ratio, R.T. 2mTorr working pressure and a 0.8A sputtering current. The film thickness and c-axis preferred orientation of ZnO/AZO/glass thin films were measured by ${\alpha}$-step and an x-ray diffraction (XRD) instrument. In the results, we could prepare the ZnO thin film with c-axis preferred orientation of about 6$^{\circ}$ on substrate temperature R.T. at O$_2$ gas flo rate 0.5.

• Korean Journal of Veterinary Research
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• v.52 no.3
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• pp.177-181
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• 2012

Actinobacillus (A.) pleuropneumoniae is the causative agent of pleuropneumonia which is one of the most important respiratory diseases in pigs worldwide. A total of 32 A. pleuropneumoniae isolates from diseased pigs during 2008 to 2010 were serotyped by polymerase chain reaction method. The susceptibility of the isolates to 13 antimicrobial agents were determined by disk diffusion test. In all the 32 isolates examined in this study, serotype 5 (16 isolates: 50%), 1 (7 isolates: 21.9%), 2 (5 isolates: 15.6%) and 12 (1 isolate: 3.1%) were found. Of all tested antimicrobial agents, resistance to oxytetracycline was found in 96.9% of isolates, followed by resistance to amikacin (81.2%), neomycin (68.7%), kanamycin (53.1%), penicillin (50.0%), gentamicin (43.7%), florfenicol (25.0%), ampicillin (18.7%), colistin (9.4%), trimethoprim/sulfamethoxazole, ceftiofur (8.3%), amoxicillin/clavulanic acid (3.1%) and enrofloxacin (0%). Oxytetracycline or florfenicol-resistant isolates were examined for the presence of resistance gene. Among the 31 oxytetracycline-resistant isolates, tetB, tetH and tetO genes were detected in 22 (71%), 8 (26%) and 1 (3%) isolates, respectively. The floR genes were detected in 8 (100%) of the 8 florfenicol-resistant A. pleuropneumoniae isolates.