• Journal of Radiation Protection and Research
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• v.26 no.1
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• pp.7-12
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• 2001

Sintered LiF:Mg,Cu,Na,Si thermoluminescence (TL) pellets were developed for application in radiation dosimetry. In the present study, the TL dosimetric properties of LiF:Mg,Cu,Na,Si TL pellets have been investigated for emission spectrum, dose response, energy response, and fading characteristics. LiF:Mg,Cu,Na,Si TL pellets were made by using a sintering process, that is, pressing and heat treatment from TL powders. Photon irradiations for the experiments were carried out using X-ray beams and a $^{137}Cs$ gamma source at the Korea Atomic Energy Research Institute (KAERI). The average energies and the dose were in the range of 20-662 keV and $10^{-6}-10^{-2}\;Gy$, respectively. The glow curves were measured with a manual type TLD reader(System 310, Teledyne) at a constant nitrogen flux and a linear heating rate. For a constant heating rate of $5^{\circ}C\;s^{-1}$, the main dosimetric peak of glow curve appeared at $234^{\circ}C$, the activation energy was 2.34 eV and frequency factor was $1.00{\times}10^{23}$. TL emission spectrum is appeared at the blue region centered at 410 nm. A linearity of photon dose response was maintained up to 100 Gy. The photon energy responses relative to $^{137}Cs$ response were within ${\pm}20%$ at overall photon energy region. The fading of TL sensitivity of the pellets stored at the room temperature was not found for one year.

• Journal of the Korean Society of Industry Convergence
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• v.8 no.3
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• pp.135-141
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• 2005

The static friction coefficients of 4 samples against each different temperatures were similar values. Compared against RT, at $80^{\circ}C$ the static friction coefficients decreased from 0.130 to 0.116 that was equal from 88% to 90% of the static friction coefficients respectively. Otherwise the dynamic friction coefficients compared against RT, decreased from 0.138 to 0.088 which was from 71% to 77.5% respectively at $80^{\circ}C$. The noise characteristics were judged by s/d value. And when the s/d value was limited less than 0.8, noise concerns were released. At 3000 engaging cycles the static friction and the dynamic friction coefficient were 0.137 and 0.073 respectively. When plate pressure rose up to $195kg_f/cm^2$, the static friction coefficient decreased from 0.137 to 0.125 but this decreasing could be considered as stable. When speed rose up to 2200rpm, the static friction coefficient decrease from 0.14 to 0.13 but this decreasing could be considered as stable. At 3000 engaging cycles the amount of worn out was 0.04 : the thickness of disc was decrease from 4.72mm to 4.68mm. But regarding the normal operation condition, further more worn-out could not be expected. Therefore concerning worn-out, the basic oil could be considered as appropriate.

• Journal of Plant Biology
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• v.39 no.2
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• pp.137-144
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• 1996

Scanning electron microscope revealed several taxonomically useful characters in the perigynium and achene epidermis of sect. Siderosticatae (Carex siderosticta, C. ciliatomarginata and C. okamotoi). Mocroscopic characters such as perigynium shape, hair presence or absence, beak shape, nodule situation in perigynium, achene shape, cell wall and silica cone in achene were useful in Carex at the species levels. A key was presented on the basis of features obtained from the examinations.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.137-138
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• 2015

본 논문은 알루미늄 재질로 된 방열판을 LED조명기구에 적용해서 열 해석을 한 것으로서, PCB에 25[W]급 LED를 배치하여 COMSOL Multi-physics로 시뮬레이션 하였다. 그 결과 LED와 PCB 경계면의 온도는 $69^{\circ}C$이고, PCB바닥면의 온도는 $28^{\circ}C$로 실제작한 FR-4 재질의 LED Module과 근접한 온도임을 확인 할 수 있었다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.137-141
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• 1999

In this paper, we developed a Windows 95 version off-line programming system which can simulate a track vehicle model in 3D graphics space. The track vehicle was adopted as an objective model. The interface between users and the off-line program system in the Windows 95's graphic user interface environment was also studied. The developing language is Microsoft visual C++. Graphic libraries, OpenGL, by Silicon Graphics, Inc. were utilized for 3D Graphics.

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.137.2-138
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• 2000

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2002.05a
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• pp.137-137
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• 2002

Several epidemiologidal studies suggested that arsenic exposure was strongly correlated with the development of cardiovascular disease such as hypertension. In order to examine whether arsenic affects vasomotor tone in blood vessels, we investigated the effect of arsenic on agonist-induced vasorelaxation using the isolated rat aortic ring in in vitro organ bath system. Treatment with arsenite inhibited acetylcholine-induced relaxation of aortic rings in a concentration- dependent manner. The inhibitory effects by arsenic were also observed in the relaxation induced by sodium nitroprusside, a NO-donor. Consistent with these findings, the cGMP levels stimulated by acetylcholine in blood vessels were reduced significantly by arsenite treatment. In addition, higher concentration of arsenite decreased the relaxation by 8-Br-cGMP, a cGMP analog, in aortic rings without endothelium. These in vitro results indicated that arsenite that arsenite was capable of suppressing acetylcholine-induced relaxation in blood vessels by inhibiting production of nitric oxide in endothelial cells and by impairing the relaxation machinary in smooth muscle cells. In vivo studies revealed that the reduction of blood pressure by acetylcholine infusion was signigicantly suppressed after arsenite was administered intravenously to rate. These data suggest that vasomotor tone impaired by arsenite exposure may be one of the contrbuting factors in development of cardiovascular disease.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.938-944
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• 1999

Response surface methodology (RSM) was used for monitoring the changes of Hunter's color and organoleptic colors of roasted doraji tea with variations in threonine concentration of soaking solution and roasting condition. In soaking and roasting processes based on the central composite design with variations in threonine concentration of soaking solution, roasting temperature and roasting time, coefficients of determinations $(R^{2})$ of the models were above 0.87 (p<0.05) in Hunter's color parameters and organoleptic color. Hunter's color L value of roasted doragi tea was maximized in 0.09% threonine concentration of soaking solution, $142.37^{\circ}C$ and 21.94 min in roasting condition. Hunter's color a value of roasted doragi tea was maximized in 1.24% threonine concentration of soaking solution, $154.01^{\circ}C$ and 28.59 min in roasting condition, minimized in 1.67% threonine concentration of soaking solution, $137.61^{\circ}C$ and 24.62 min in roasting condition, Hunter's color b value of roasted doragi tea was maximized in 1.10% threonine concentration of soaking solution, $154.72^{\circ}C$ and 27.12 min in roasting condition. The maximum quality of organoleptic color of roasted doragi tea was soaked in 1.25% threonine concentration, and roasted at $141.81^{\circ}C$ for 34.14 min.

• The Journal of the Acoustical Society of Korea
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• v.25 no.4E
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• pp.137-141
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• 2006

This paper presents HE-AAC decoder optimization on TMS320C55x fixed-point DSP core using a DSP-C like FFR code, which provides fast and flexible porting to a DSP core. Our optimization efforts are focused on methodologies that include general optimization methods of FFR code suitable for general DSP or RISC platform in high-level language and software optimization methods in assembly language level. The implementation result requires 48 MIPS and 135 Kbytes memory space to decode 48 Kbps stereo using real Korean S-DMB data.

• Proceedings of the Korean Society of Crop Science Conference
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• 1999.05a
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• pp.136-137
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• 1999