• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.181-186
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• 1999

화학 축열 시스템의 성능을 모사하고 이를 해석하여 시스템 성능을 최적화하기 위해서는, 반응층의 열 및 물질 전달 특성을 정확히 아는 것이 중요하다. 본 연구에서는 $Na_2$S-$H_2O$ 반응계를 사용한 화학 열펌프에 대한 연구로, $Na_2$S-팽창흑연 복합체의 열전도도와 기체 투과도를 측정하였고, 소형 시스템을 제작하여 그 성능을 평가하였다. 열전도도는 전이 일차원 열류기법을 사용하여 측정하였고, 기체 투과도는 Darcy's law를 이용하여 측정하였다. 반응층의 열전도도와 기체 투과도는 팽창흑연 지지체의 겉보기 밀도와 반응염의 함량에 따라 각각 6~48W/mㆍK, 1.1$\times$$10^{-13}$~1.0$\times$$10^{-11}$m$^2$의 범위에 있었다. 또한 소형 시스템을 구성하여 445W/kgㆍ$Na_2$S의 냉방 출력을 얻을 수 있었다.

• Journal of the Korean Chemical Society
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• v.44 no.4
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• pp.322-327
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• 2000

A new absorption spectrometric method for the determination of the Cr$_2O_7^{2-}$ ionin acidic media has been developed. The new method is based on the oxidation-reduction reaction of the HCr$O_4^-$ ion with H$_2$O$_2$forming a deep blue CrO(O$_2$) $_2$ andis coupled with a technique of flow injection analysis(FIA). The new method provides a linear calibration curve which accurately follows the Beer's law over a wide range of the analytical concentrations(2.0 ${\times}$ $10^{-6}$M~8.0 ${\times}$ $10^{-3}$M) of K$_2$Cr$_2$O$_2$. The sensitivity of the new method is approximately two times greater than the current method and the effects of the interfering substances such as V, Co, Ni, Fe, and Mn are almost negligible except Cu.

• International Journal of Industrial Entomology and Biomaterials
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• v.11 no.1
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• pp.49-55
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• 2005

Two BC1 group, c108 $\times$ (p50 $\times$ c108) and p50 $\times$ (p50 $\times$ c108), one group of F$_{2}$ progeny, (p50 $\times$ c108) F$_{2}$ ,and 3 SSR markers, F10539, FlO626 and FlO618 were used to test the hereditary properties of SSR markers in silkworm. FI0539, FlO626 were proved to be linkage, and FlO618 was proved to be independent to those two markers. According to Mendel's law, the recombinant value between F10539, FlO626 was calculated in all of these groups, and they were 8.55$\%$ (c108BC1), 8.02$\%$ (p50BC1) and 7.81 $\%$ (F$_{2}$) respectively. There was dominant difference among the crossing-over value using paired-samples tests by SPSS 10.0 software. This research proved that SSR markers were co-dominant in B. mori too, and F 2 progeny could be used to construct SSR linkage map although B. mori lacked of crossing over in females.

• Journal of Drive and Control
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• v.18 no.2
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• pp.32-37
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• 2021

The piston reservoir is mainly used in hydraulic blow-down system for aerospace engineering. The reservoir is heavy due to both hydraulic cylinder and piston in pressurization. The positive expulsion tank with rubber diaphragm has been mostly applied propellant and fuel tank at low pressure to satellites. To reduce weight, the reservoir that can be used at high pressure with rubber diaphragm was developed. In this research, the prediction of life-time for the rubber diaphragm was implemented through an accelerated life test, as a part of development of new reservoir. Also, the diaphragm was stored in an temperature chamber at the same condition as and operation with hydraulic oil. As a result, the life-time for a rubber diaphragm was successfully evaluated via Arrhenius law and Time-Temperature Superposition based on failure times over temperatures in the accelerated test.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.4
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• pp.185-189
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• 2004

The temporal variation of a secondary electron emission coefficient (${\gamma}$ coefficient) of hydrogenated amorphous silicon (a-Si:H) was investigated in a dc silane plasma. Estimated ${\gamma}$ coefficients have a value of 2.73 ${\times}$ 10$^{-2}$ on the pure aluminum electrode and 1.5 ${\times}$ 10$^{-3}$ after 2 hours deposition of -Si:H thin films on a cathode. It showed an abrupt decrease for about 30 minutes before saturation. The variation of the ${\gamma}$ coefficient was estimated as a function of the thin film thickness, and the film thickness was about 80 nm after 30 minutes deposition time. These results are compared with the results of a computer simulation for ion penetration into a cathode.

• Journal of Astronomy and Space Sciences
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• v.4 no.1
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• pp.35-45
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• 1987

The peculiar elliptical (EOp) galaxy NGC 4486 and two KOII comparison stars HR5450, HR6935 were observed spectroscopically using the 74-inch telescope and Image Tube at Mt. Stomlo Observatory. From the Gaussian Broadening Function, broadened spectrum of two comparison stars were computed for the range between wavelength 4800$\AA$ and 5400$\AA$. Velocity dispersions in the line of sight of M87 were obtained by visual fitting. The fitted velocity dispersion is 450 km/sec at the nucleus, 350km/sec at r=12", and 300km/sec at r=24". Using the photometric data and the central value of velocity dispersion, we determined the mass of M87. From <$r^{2/4}$ law and the Virial theorem the calculated total mass in $2.1\times10^{12}M_\odot$ and from the King Model $M=1.2\times10^{12}M_\odot$. And M/L ratio of M87 is about 30.

• YAKHAK HOEJI
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• v.31 no.2
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• pp.45-51
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• 1987

Methyl orange(MO) and cetyltrimethylammonium bromide(CTA) were mixed and added to 10ml of the buffer solution and then the solution was shaken for 5 minutes. The maximum absorption wavelength of the reaction product was 419nm. Dichloromethane was the best extracting solvent among the several organic solvents and the most suitable pH range was 2~8. When the CTA-MO calibration curve was made in the best experimental condition, the Lambert-Beer's law was obeyed in the range of CTA concentration of $1.5\times$$10^{-5}$~1.0$\times$$10^{-4}M$ by UV spectrophotometer. This method was possible to determine quaternary ammonium salts in the pharmaceutical preparations.

• YAKHAK HOEJI
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• v.35 no.1
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• pp.15-21
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• 1991

Quaternary amines which are widely used as medicines are nitrogen compounds. Metanil yellow(MY) and benzalkonium chloride(BKC) were mixed and added to 10ml of the buffer solution and then the solution was shaken for 5 minutes. The maximum absorption wavelength of the reaction product was 402 nm. Dichloromethane was the best extracting solvent among the several organic solvents and the most suitable pH range was 2~8. When the BKC-MY calibration curve was made in the best experimental condition, the Lambert-Beer's law was obeyed in the range of BKC concentration of 2$\times$$10^{-6}$~9$\times$$10^{-6}$M by UV spectrophotometer. This method was possible to determine quaternary ammonium salts in the pharmaceutical preparation.

• Journal of the Korean Ceramic Society
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• v.28 no.2
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• pp.109-118
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• 1991

Steady-state sublimation vapour pressures of anhydrous bismuth triiodide have been measured by the torsion-effusion method from 488.8 to 570.5 K and equilibrium sublimation pressures were obtained from the steady-state data. The standard sublimation enthalpy changes derived by both second(modified sigma function) and third(average enthalpy method) law methods were 159.316${\pm}$0.055, 137.67${\pm}$1.43 kJ$.$mol-1 respectively. The standard sublmation entropy change derived by modified sigma function was 232.88${\pm}$0.10 J$.$K-1$.$mol-1. The reliable standard sublimation enthalpy change based on a correlation of {{{{ { TRIANGLE }`_{cr } ^{g } }} H{{{{ { 0} atop {m } }}(298.15K) and {{{{ { TRIANGLE }`_{cr } ^{g } }} S{{{{ { 0} atop {m } }}(298.15K), a recommended p(T) equation has been obtained for BiI3(cr) ; lg(p/Pa)=-(C$.$K/T)+5.071lg(T/K)-2.838${\times}$10-3(T/K)-7.758${\times}$103(K/T)2+1.4519 where C={{{{{ { TRIANGLE }`_{cr } ^{g } }} H{{{{ { 0} atop {m } }}(298.15K)/0.019146 kJ$.$mol-1}-456.27.

• Journal of the Korean Society of Radiology
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• v.7 no.5
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• pp.333-338
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• 2013

Generally, it's known fact that intensity of radioactivity satisfies inverse-square law. However, the law was dissatisfied with practical experiment because of limited shape of scintillation detector. Especially, in the case of near distance between the surface of detector and the radioactive source, the difference grows larger. In the present study, reason of this difference was confirmed by experiment with $2^{{\prime}{\prime}}{\times}2^{{\prime}{\prime}}{\phi}$ NaI(Tl) scintillation detector and $^{60}Co$(1.174 MeV, 1.333 MeV)and $^{137}Cs$(0.662 MeV) gamma ray sources. From the experiment, the correction coefficient was obtained with gamma ray detection efficiency and geometrical volume. In the result of the present study, the efficiency difference of the detector was corrected with the coefficient. In the present result, we obtained that the inverse-square law experiment have to consider the efficiency and geometrical value of the detector.