• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.155-158
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• 1997

In design of current transformer, equivalent circuit parameters is obtained by electromagnetic analysis and used circuit simulation. Precise core secton area and turns of coil can be determined by circuit analysis. Therefore exact design of current transformer is possible by field and circuit analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.1020-1023
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• 2004

Recently, Cooling tower are used the necessary element in a residential area and living space on the viewpoint of indoor temperature control. The purpose of this study is to assistance the comfortable environment and economical measures of noise transmission mechanism on tile cooling tower. The results show that noise evaluation interact the main factor of distance reduction and diffraction reduction. Noise criterion apply to the NC level and equivalent transmission loss about already the design of noise reduction.

• 한국수학사학회지
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• 제31권6호
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• pp.315-337
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• 2018

Pythagorean thoerem exists in several equivalent forms in the Euclidean plane, that is, the Hilbert plane which in addition satisfies the parallel axiom. In this article, we investigate the truthness and mutual relationships of those propositions in various non-Hilbert planes which satisfy the parallel axiom and all the Hilbert axioms except the SAS axiom.

• 대한설비공학회지:설비저널
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• 제8권2호
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• pp.95-100
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• 1979

Optlmum overall heat transmission coefficient for residential buildings is calculated as a function of building parameter, area/volume. Equivalent heat transmission coefficient and equivalence factor are introduced and optimized with respect to annual cost including fuel cost , insulation cost and equipment cost Comparison with recent standard of West Germany shows similarity of the result.

• 한국식품영양과학회지
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• 제45권6호
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• pp.918-922
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• 2016

본 연구에서는 귀리 추출물에 대한 항산화 활성과 암세포 증식 억제 활성을 측정하고 각 추출용매에 따른 차이를 비교 분석하고자 하였다. 추출물의 항산화 활성은 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)(ABTS)와 1,1-diphenyl-2-picrylhydrazyl(DPPH) 라디칼 제거능 및 환원력을 이용하여 측정하였으며, 암세포 증식 억제 활성은 대장암, 폐암 및 유방암 세포주를 이용하여 평가하였다. 총 폴리페놀 함량, ABTS 및 DPPH 라디칼 제거능, 환원력 모두 methanol 추출물이 각각 8.2 mg gallic acid equivalent/g residue, 12.1 mg Trolox equivalent antioxidant capacity(TEAC)/g residue, 4.4 mg TEAC/g residue 및 $A_{700}=0.39$로 가장 높은 활성을 나타내었다. 또한 암세포 증식 억제 활성은 methanol 추출물이 대장암(HCT116), 폐암(NCI-H460) 및 유방암(MCF7) 세포에서 각각 69.5, 75.2 및 84.8%로 높은 증식 억제 활성을 나타내었다. 따라서 추출용매에 따라 귀리의 항산화 및 암세포 증식 억제 활성에 차이가 나타나며, 이는 추출용매의 극성에 따라 추출된 생리활성 물질, 특히 폴리페놀 화합물의 용해도 차이로 생각된다. 본 연구 결과는 점차 관심이 높아지고 있는 천연 항산화제 및 항암제로서 귀리에 관한 생리활성 연구에 있어 기초자료로 활용될 수 있을 것으로 생각되며, 귀리의 소비 촉진에 영향을 끼칠 것으로 생각된다.

• Structural Engineering and Mechanics
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• 제62권3호
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• pp.273-279
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• 2017

A meso-scale model is proposed to study filament-wound composites with fiber undulations and crossovers. First, the crossover and undulation region is classified as the circumferential undulation and the helical undulation. Next, the two undulations are separately regarded as a series of sub-models to describe the meso-structure of undulations by using meso-parameters such as fiber orientation, fiber inclination angle, resin rich area, fiber volume fraction and bundle cross section. With the meso-structure model and the classic laminate theory, a method for calculating the stiffness of filament wound composites is eventually established. The effects of the fiber inclination angle, the fiber and resin volume fraction and the resin rich area on the stiffness are studied. The numerical results show that the elastic moduli for the circumferential undulation region decrease to a great extent as compared with that of the helical undulation region. Moreover, significant decrease in the elastic and shear moduli and increase in the Poisson's ratio are also found for the resin rich area. In addition, thickness and bundle section have evident effect on the equivalent stiffness of the fiber crossover and the undulation region.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.496-499
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• 2008

The noise reducing devices installed on the noise barrier have been developed in many shapes and ways to reduce noise around road traffic areas. In this study, test and estimation method for the noise reducing device witch installed on the top of a noise barrier was suggested. For this, the authors have considered sound power flow around the device and sound pressure levels for the far field area. To estimate the area effect behind the barrier, area average of noise pressure level difference divided by two area, upper and bellow the sight-line. Comparing the attenuation difference of these areas, the tendency of noise reduction effect was studied according to type of noise reducing devices. Compared with noise shielding efficiency of the devices that using equivalent height of a simple barrier calculated by the SoundPlan, the commercial environment noise simulation software.

• 환경위생공학
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• 제16권1호
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• pp.18-26
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• 2001

The increase of economic growth has brought out the noise pollutions in city regions. To evaluate these problems, this study was investigated to assessment and analysis of noise pollutions at Cheongju area in winter and summer seasons. The noise levels were measured and analyzed at the general areas the 4 roadside areas (park, residential, commercial, and industrial area). As a result, following facts have been found. The equivalent sound levels(Leq) at general are in winter were 51.3∼78.2 dB(A) at the daytime and 41.1∼63.1 dB(A) at the nighttime And in summer there were 53.5∼77.3 dB(A) at the daytime and 41.9∼64.0 dB(A) at the nighttime, respectively. These values were higher than average value of Korea. At the roadside area, the values of Leq were 51.9∼72.8 dB(A) at the daytime, 44.3∼68.2 dB(a) at the nighttime in winter, and in summer there were 62.5∼73.1 dB(A) at the daytime and 50.4∼68.3 dB(A) at the nighttime, respectively. These values were lower than average value of Korea. The calculated traffic noise index(TNI) were 64.6∼93.6 at the daytime and 26.5∼106.6 at the nighttime in winter, In summer, there were 65.0∼90.7 at the daytime, and 32.3∼91.8 at the nighttime. The TNI values varied wide ranges at the nighttime according to traffic volumes.

• 통합자연과학논문집
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• 제7권1호
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• pp.39-44
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• 2014

The results of the synoptic meteorological analysis showed that when the cold and dry continental high pressure was extended, heavy snow occurred at dawn when the upper atmosphere cooled. In particular, when the continental high pressure was extended and the upper pressure trough passed through, heavy snow occurred due to the convergence region formed in the west coast area, sometimes in the inland of the Honam area. In addition, it was verified that the changes in the humidity coefficients in the upper and lower layers are important data for the determination of the probability, start/end and intensity of heavy snow. However, when the area was influenced by the middle-latitude low pressure, the heavy snow was influenced by the wind in the lower layer (925 hPa and 850 hPa), the equivalent potential temperature, the convergence field, the moisture convergence and the topography. In Case 2010 (30 December 2010), OSTIA had the best numerical simulation with diverse atmospheric conditions, and the maximum difference in the numerically simulated snowfall between NCEP/NCAR SST and OSTIA was 20 cm. Although there was a regional difference in the snowfall according to the difference in the SST, OSTIA and RTG SST numerical tests, it was not as significant as in the previous results. A higher SST led to the numerical simulation of larger snowfall, and the difference was greatest near Buan in the west coast area.

• 한국지형학회지
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• 제24권1호
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• pp.63-76
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• 2017

This research was classified mountain areas with high ecological, environmental and resource value among the macro scaled terrain that can be checked at the space scale of less than 1:1,000,000 and analyzed the topographical characteristics. It has been confirmed that the mountains of the Korean peninsula belong to the groups IV, V, VI(classification by Kapos et al.(2000)) as a result of applying the quantitative standards for designation of mountain areas to the global mountain system. The area of mountains calculated using high resolution DEM is equivalent to 48% of the area of the Korean peninsula, and the result is quite different from the general idea of which 70% is the mountain area of the Korean peninsula. The mountain areas show the distribution of geomorphons, that is different from the plains and the hills and also, it shows the differences between the mountains of the groups IV~ VI classified according to the altitude. As a result of analyzing the relations among type pattern, slope, and relief, specific geomorphons are concentrated at $10^{\circ}$ and $20^{\circ}$ and it shows the possibility to classify the mountainous areas into two groups based on the result that the distribution of landform patterns are bimodal in the relation to the amount of relief.