• Elastomers and Composites
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• 제35권1호
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• pp.63-70
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• 2000

아연 도금된 강철 타이어 코드의 접착성 향상을 위하여 아르곤 플라즈마로 에칭후 아세틸렌 또는 부타디엔 플라즈마 고분자 중합으로 코팅하였다. 플라즈마 고분자 중합은 10W, 30분, 30mTorr에서 실시하였으며, 아르곤 에칭은 90W, 30초, 30mTorr에서 실시하였다. 타이어 코드의 접착력은 TACT으로 측정하였으며, 파괴 표면을 주사전자현미경으로 분석하였다. 또한 플라즈마고분자로 코팅된 타이어 코드의 표면을 FT-IR, Alpha-step 및 접촉각 측정기로 분석하여 접착 메카니즘을 규명하고자 하였다.

• 한국산업보건학회지
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• 제27권2호
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• pp.123-129
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• 2017

Objectives: The purpose of this study is to enhance the application of analytical method of polar solvents(alcohols) by GCOTC (gas chromatography open tubular column) through the system suitability test(SST) to estimate the whole chromatographic system performance(integral part). Methods: To perform the SST, carried out repeatability(n=6) as analytical method of polar solvents by GCOTC, got the retention time($t_R$), standard deviation(${\sigma}_{n-1}$) of $t_R$, baseline width($w_b=4{\sigma}_{n-1}$) and calculated dead time($t_m$) by $v_m=d^2{\pi}L(f/4)$ and $v_m=t_m$ x flow rate. Results: In this experiment, obtained the basic data, there were $t_m=2$ min, methanol($t_R=3.569$, ${\sigma}_{n-1}=0.01$, $w_b=0.04$), ethanol ($t_R=3.892$, ${\sigma}_{n-1}=0.004$, $w_b=0.016$), isopropanol($t_R=4.209$, ${\sigma}_{n-1}=0.004$, $w_b=0.016$). By using these data, calculated the corrected retention time($t_R{^{\prime}}$), capacity factor(k), separation factor(${\alpha}$), number of theoretical plate(n) and resolution($R_s$) for SST and got the good results. Conclusions: Through the SST, could reconfirm the whole chromatographic performance system(integral part) for analytical method of polar solvents by GCOTC. Therefore, this analytical method expect to be widely applied at the related areas.

• Current Photovoltaic Research
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• 제10권2호
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• pp.56-61
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• 2022

Recently, the expansion of the domestic solar market due to the promotion of eco-friendly and alternative energy-related policies is promising, and it is expected to lead the high-efficiency/high-power module market based on M10 or larger cells to reduce LCOE, 540-560W, M12 based on M10 cells Compared to the existing technology with an output of 650-700W based on cells, it is necessary to secure competitiveness through the development of modules with 600W based on M10 cells and 750W based on M12 cells. For the development of high efficiency/high-power n-type bifacial, it is necessary to secure a lightweight technology and structure due to the increase in weight of the glass to glass module according to the large area of the module. Since the mechanical strength characteristics according to the large area and high weight of the module are very important, design values such as a frame of a new structure that can withstand the mechanical load of the Mechanical Load Test and the location of the mounting hole are required. In this study, a structural analysis design model was introduced to secure mechanical reliability according to the enlargement of the module area, and the design model was verified through the mechanical load test of the actual product. It can be used as a design model to secure the mechanical reliability required for PV modules by variables such as module area, frame shape, and the location and quantity of mounting holes of the structural analysis model verified. A relationship of output drop can be obtained.

• Advances in concrete construction
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• 제11권4호
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• pp.285-298
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• 2021

This study focused on experimental evaluation of mechanical properties of pervious concrete mixtures with the aim of achieving higher values of strength while considering the associated costs. The effectiveness of key parameters, including cement content, water to cement ratio (W/C), aggregate to cement ratio (A/C), and sand replacement was statistically analyzed using paired-samples t-test, Taguchi method and one-way ANOVA. Taguchi analysis determined that in general, the role of W/C was more significant in increasing strength, both compressive and flexural, than cement content and A/C. It was found that increase in replacing percent of coarse aggregate with sand could undermine specimens to percolate water, though one-way ANOVA analysis determined statistically significant increases in values of strength of mixtures. Cost analysis revealed that higher strengths did not necessarily correspond to higher costs; in addition, increasing the cement content was not an appropriate scenario to optimize both strength and cost. In order to obtain the optimal values, response surface method (RSM) was carried out. RSM optimization helped to find out that W/C of 0.40, A/C of 4.0, cement content of about 330 kg/m3 and replacing about 12% of coarse aggregate with sand could result in the best values for strength and cost while maintaining adequate permeability.

• 한국항공운항학회지
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• 제12권2호
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• pp.1-15
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• 2004

In this study, we analyze technical requirements for a 50m unmanned airship order to assure safety in the test flight operation. The 50m class unmanned airship developed by Airship Group in Korea Aerospace Research Institute(KARI). The 50m class unmanned airship was developed as a scale-down model of 200m class stratosphere unmanned airship. This study reviews specifications and characteristics of 50m class unmanned airship and develops Airworthiness Requirements on the basis of current effective Aviation Act, Airworthiness standards, and relevant international documents. The developed requirements can be applied to the safety assessment of the 200m class stratosphere unmanned airship.

• International Journal of Reliability and Applications
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• 제15권1호
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• pp.11-22
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• 2014

New classes of life distributions called new better (worse) than used at age $t_0$ in Laplace transform order, NBUL- $t_0$(NWUL - $t_0$) are introduced. For the classes NBUL - $t_0$(NWUL - $t_0$), preservation under convolution, mixture, mixing and the homogeneous Poisson shock model are studied. In the sequel, we obtain a test for $H_0$ : F is exponential versus $H_1$ : F is NBUL - $t_0$ and not exponential. The critical values and the powers of this test are calculated to assess the performance of the test. It is shown that the proposed test has high efficiencies for some commonly used distributions in reliability. Sets of real data are used as examples to elucidate the use of the proposed test for practical problems.

• 한국분말재료학회지
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• 제11권2호
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• pp.149-157
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• 2004

High temperature deformation behavior of activated sintered W powder compacts was investigated. The compression tests were carried out in the temperature range between 900 and 110$0^{\circ}C$ at the strain rate of $10^{-3}s^{-1}$. The sintered specimens of Ni-doped submicron W powder compacts showed decrease in W grain size with increasing the Ni content. As the result, the flow stress was significantly increased with increasing the Ni content. We obtained Ni-activated sintered W compacts with the relative density of 94 $\pm$ l％and the average grain size of less than 5${\mu}{\textrm}{m}$. A moderate true strain up to 0.60 was obtained without fracture even at 110$0^{\circ}C$ with the strain rate of $10^{-3}s^{-1}$ for the activated W compact despite adding the 1.0 wt％Ni to submicron W powder.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.275-279
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• 2005

The vortex convection and induced flow field behind the KARI 3m x 4m LSWT gust generator was computed by using Computational Fluid Dynamics. For the accurate simulation of vortex convection, inviscid, laminar, Spalart-Allmars k-e and k-w turbulence models were tested with the NAL gust generator configuration and Spalart-Allmaras turbulence model was selected for the prediction of induced flow field behind the KARI LSWT gust generator. The wind tunnel test was also carried out at KARI LSWT and the results were compared with CFD prediction.

• 천문학회보
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• 제43권1호
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• pp.50.1-50.1
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• 2018

We present the development of tools for Echelle spectrograph of NYSC 1-m telescope. The eShel spectrograph(Shelyak) has operated at Deokheung Optical Astronomy Observatory since 2016. We carried out test observation in 2016 and completed the preprocessing and wavelength calibration of the spectroscopic data using IRAF. Based on the reduction process in IRAF, PySpecW, a set of tools for spectroscopic data was developed in 2017. PySpecW was optimized for NYSC 1m telescope, and written in Python for youth to use easily on any OS. PySpecW consists of preprocessing, aperture tracing, aperture extraction, wavelength calibration, and dispersion correction for extracted spectra.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.393-395
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• 2003

This paper deals with the monitoring program based on Windows for Distribution Panel Tester. The monitoring software has variety function : data file conversion, user define data generation, data metering and signal analysis etc. The software is designed for GUI because it provides easy test and control interface for users or operators.