• 조명전기설비학회논문지
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• 제17권1호
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• pp.80-85
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• 2003

본 논문에서는 유도가열조리기의 효과적인 설계를 위하여 입력주파수 변화에 따른 유도가열조리기의 자계와 열계 해석 방법을 제시하였다. 유도가열조리기의 내부자계는 3차원 축대칭 유한요소법을 사용하여 해석하였으며, 열원은 유도가열조리기의 내부에서 유도된 와전류에 의하여 발생되고, 열은 열원과 열방정식을 사용하여 계산되어진다. 또한, 유도가열조리기의 온도특성을 스테인레스와 알루미늄 각각에 대하여 주파수와 투자율에 따라 제시하였다.

• 조명전기설비학회논문지
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• 제26권9호
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• pp.26-32
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• 2012

This paper calculates the core and copper losses as heating sources of a 24MVA cast resin transformer, and analyzes the thermal distribution of the transformer to find out its hot-spot area by FEM program. Since the winding of the transformer is composed with many series and parallel circuits, the analyzing model of the winding is simplified and modelled by axi-symmetric domain. As the results, the maximum temperature is estimated by $137^{\circ}C$ in the upper part of the low-voltage winding. The maximum temperature has discrepancy of approximately $10^{\circ}C$, which is able to be considered as an acceptable error range in the design stage of power transformers. For the overall pattern of the temperature distribution is almost same as test results, the analyzing method can be a useful tool to find out a hot-spot area of the winding.

• 대한방사선기술학회지:방사선기술과학
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• 제16권1호
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• pp.101-106
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• 1993

In order to assure safety of both patient and operator, and to provide uniform quality radiographs, it is necessary to perform periodic calibration of diagnostic X-ray equipment. A basic parameter of diagnostic equipment's and its image sharpness is the size(and shape the energy distribution) of the focal spot as viewed along the central X-ray beam. This size determines the resolution possible with the equipment and also determines the heat characteristics of an anode. A fine focus tube gives high resolution but causes high local heating of target. In past, the pin-hole and star pattern image measurement for evaluation of resolution have been widely used, but it produced blurring and inaccuracy of image. So newly inverted Ug-meter has advantage in more convenient measurement method and less out-put bias than other image measurement. The authors intended to compare measured focal size between Ug-meter and focal spot test tool, changed state from setting to now of units.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.462-473
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• 2019

The effects of the location and dimension of the gate, location, and volume of the feeder, application of a chill, chill volume, and heating method of the feeder with respect to the effect of the mold-designing technologies on the defect status of the products are described. It is possible to increase the solidification time of the feeder by heating feeder. Furthermore, the pressure generated from the feeder is imposed on a product, and this decreases the generation of shrinkage porosities. In this study, two types of gating and feeding systems had been proposed: the bottom L-type junctions and the top L-type junctions. Additionally, solidification behaviors, such as solidification time, shrinkage porosities, weight percentage of chill system to product, hot spot, and solidification time ratio (=Solidification time of feeder/solidification time of product), are extensively analyzed by using commercial casting simulation software. Based on the solidification behaviors, reasonable mold design, feeding system, critical feeder heating temperature, and solidification time ratios are proposed in the sand casting process for the fabrication of carrier housing in order to reduce the casting defects and to increase the recovery rate.

• 비파괴검사학회지
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• 제19권1호
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• pp.16-24
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• 1999

잔류응력은 공학적 구조물에 결함을 야기하는 유해한 응력이므로 산업현장에서는 이를 측정하기 위한 많은 관심을 가지고 있다. 현재 잔류응력 측정은 일반적인 방법을 사용하고 있지만 이러한 방법들은 어느정도 문제점을 내포하고 있다. 그러므로 레이저 스페클 간섭법에 유한요소법과 점 가열법을 혼합하여 산업 현장에 유해한 잔류응력을 측정할 수 있는 새로운 기법을 개발하였다. 이 기법에서 사용된 레이저 스페클 간섭계는 측정 시편의 응력이 풀릴 때의 면내 변형을 측정하기 위해서 사용되어 졌으며, 유한요소법은 응력 풀림을 위한 가열부의 온도와 그 밖의 변수들을 결정하기 위해서 사용되어 졌다. 잔류응력은 측정하고자 하는 부위의 가열 냉각에 의한 변형률에 의해 결정되어지며, 이에 대한 간단한 모델링을 제시하였다. 또한 본 실험은 변형의 3차원 정량화를 수행하기 위해서 레이저 스페클 간섭계의 전자 광학적 기법 중의 하나인 위상이동법을 이용하여 수행되어졌다.

• 한국주거학회논문집
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• 제24권6호
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• pp.189-197
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• 2013

The purpose of the study was to analyze the improvement elements depended on housing quality measurement tool related to mental health. The data for the analysis was collected through questionnaire survey method from November 1, 2012 to January 17, 2013, and the sample consisted of 720 respondents living in single detached houses, multi-families detached houses, apartments, and town houses in 4 cities, Seoul, Busan, Daejeon, and Kwangju. The data were analyzed using descriptive statistics. The results of improvement elements are as follows: 1) Pedestrian-threaten street from cars in physical safety 2) A secluded or dark spot and fear of walking at night in social security, 3) Indoor noise, outdoor noise, and evidence of abandoned trash heap/bottle in neighborhood in health & sanitation, 4) Illegal parking and heating control system in facility convenience, 5) Extra kitchen, number of bathrooms, and community spaces in space convenience, 6) Openness and spaciousness of indoor room, and satisfaction of house and neighborhood in comfort, 7) Management common/sharing space in maintenance, 8) Energy saving facility and environment friendly materials use in sustainability, 9) Burden on housing cost, asset value on house, and school district in economic value, 10) Reflection of residents style, surrounding building's number of layers, and neighborhood appearance of preference in housing environment image.

• 복식문화연구
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• 제12권4호
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• pp.579-590
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• 2004

This research was aimed to investigate and compare the effectiveness of TLC and GC-MS methods in the analysis of chromophoric substances extracted from madder plant. Alizarin and purpurin 0.3% solution were used as comparative standards; madder extraction was prepared by heating the solution of powdered madder at 80℃, pH 1.5, for 90 min. Best elution solvent for TLC in silica gel plate was toluene:ethyl acetate=9:1, which resulted in red and yellow spots from madder extraction each of which showed R/sub f/ values 0.32-0.43 and 0.07-0.11. Although the red spot in particular exhibited similar characteristics as standard purpurin in color, shape, and R/sub f/ values, the result was inconsistent throughout different TLC trials. GC-MS analysis showed only small amount of alizarin and no purpurin in the madder extraction. Other chromophoric substance such as 2-furancarboxaldehyde, 5-(hydroxymethyl)-, anthralin, and danthron were also detected in small amounts. The result indicated that TLC was less sensitive to detecting and identifying the natural dyestuff which is generally constituted with a number of similar but chemically different chromophoric substances.

• Current Optics and Photonics
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• 제8권2호
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• pp.138-150
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• 2024

This study is essential for advancing our knowledge about the interaction between long-range high-power lasers and energetic materials, with a particular emphasis on understanding the response of a 155-mm shell under various surface irradiations, taking into account external factors such as atmospheric disturbances. The analysis addresses known limitations in understanding the use of non-realistic targets and the negligence of ambient conditions. The model employs the three-dimensional level-set method, computer-aided design (CAD)-based target design, and a message-passing interface (MPI) parallelization scheme that enables rapid calculations of the complex chemical reactions of the irradiated high explosives. Important outcomes from interaction modeling include the accurate prediction of the initiation time of ignition, transient pressure, and temperature responses with the location of the initial hot spot within the shell, and the relative magnitude of noise with and without the presence of physical ambient disturbances. The initiation time of combustion was increased by approximately a factor of two with atmospheric disturbance considered, while slower heating of the target resulted in an average temperature rise of approximately 650 K and average pressure increase of approximately 1 GPa compared to the no ambient disturbance condition. The results provide an understanding of the interaction between the high-power laser and energetic target at a long distance in an atmospheric condition.

• 한국의학물리학회지:의학물리
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• 제24권2호
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• pp.92-98
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• 2013

여러 치료선량 측정기들 중 치료 현장에서의 사용이 간편한 형광물질 기반 측정기인 유리선량계(Glass Rod Dosimeter, GRD)는 방사선 조사 후 측정 소자의 안정화를 위한 전처리(Pre-processing) 과정이 필수적이며, 가열방식($70^{\circ}C$, 30분)과 대기방식($20^{\circ}C$, 24시간)의 두 가지의 전처리 방식이 사용되고 있다. 본 연구에서는 각각의 전처리 조건이 측정 결과에 미치는 영향을 분석하여 사용자들에게 유용한 참고자료를 제시하고자 한다. 20개의 GRD 소자들 모두에 같은 선량을 조사한 후, 10개씩 나누어 각각 다른 전처리 방식을 사용하여 판독함으로써 각 전처리 방식의 특징들을 상호 비교하였다. 가열방식의 경우 소자 간 판독 편차는 1.13%, 시간에 따른 평균 판독값의 편차는 최대 5.33%였다. 대기방식의 경우에는 소자 간 판독 편차가 0.49%, 시간에 따른 평균 판독값의 편차는 최대 1.28%로 나타났다. 또한 동일한 선량을 주었을 때 전처리 방식에 따라 판독 절대값은 4.1%의 차이를 보였다. 또한 251명의 환자들을 대상으로 한 임상 측정 평가 결과 부위에 따라 다르지만 평균적으로 5% 이내의 측정 오차를 보였으나, 대기 방식의 경우 판독 시점에 따른 영향이 상대적으로 크게 나타났다. 결론적으로 GRD는 치료 현장에서 사용하기에 적합하나 신속한 판독이 요구되지 않는다면 대기방식의 전처리가 보다 적합하며 정해진 판독 시점을 지켜야 한다. 또한 치료 부위 등 조사 조건의 변화에 관계없이 안정적인 정확성을 기대할 수 있는 측정 방법에 대한 연구가 향후 필요하다고 생각된다.

• 한국축산식품학회지
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• 제35권4호
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• pp.473-478
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• 2015

The aim of this study was to screen and In vitro characterize the properties of bacteriocin produced by lactic acid bacteria isolated from Vietnamese fermented pork (Nem chua). One hundred and fifty LAB were isolated from ten samples of Nem chua and screened for bacteriocin-producing lactic acid bacteria. Antimicrobial activity of bacteriocin was carried out by spot on lawn method against both gram positive and gram negative bacteria. One isolate, assigned as KL-1, produced bacteriocin and showed inhibitory activity against Lactobacillus sakei, Leuconostoc mesenteroides and Enterococcus faecalis. To characterize the bacteriocin-producing strain, optimum temperature, incubation period for maximum bacteriocin production and identification of bacteriocin-producing strain were determined. It was found that the optimum cultivation temperature of the strain to produce the maximum bacteriocin activity (12,800 AU/mL) was obtained at 30℃. Meanwhile, bacteriocin production at 6,400 AU/mL was found when culturing the strain at 37℃ and 42℃. The isolate KL-1 was identified as L. plantarum. Antimicrobial activity of cell-free supernatant was completely inhibited by proteolytic enzyme of trypsin, alpha-chymotrypsin and proteinase K. Bacteriocin activity was stable at high temperature up to 100℃ for 10 min and at 4℃ storage for 2 d. However, the longer heating at 100℃ and 4℃ storage, its activity was reduced.