• Analytical Science and Technology
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• v.15 no.5
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• pp.433-438
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• 2002

Trace elements in two air filters (V-50, P-50) artificially loaded with urban dust provided from IAEA were determined non-destructively using instrumental neutron activation analysis. Standard reference material (Urban Particulate Matter, SRM 1648) of National Institute of Standard and Technology was used for analytical quality control. About 20 elements in both of loaded filter samples were determined. To evaluate inter-laboratory comparison and proficiency test, analytical data were statistically treated with the results which collected from 49 laboratories, 40 countries participated in this study using neutron activation analysis, particle induced X-ray emission, inductively coupled plasma mass spectroscopy, etc,. From the results of statistical treatment, Z-scores are within ${\pm}2$. Furthermore, accuracy and precision of obtained analytical values are passed according to the criteria of the proficiency test. Consequently, it was proved that analytical quality for air dust samples being performed has been controlled properly.

• Journal of Energy Engineering
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• v.16 no.1 s.49
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• pp.46-52
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• 2007

The piecewise constant angular approximation is developed to replace the conventional angular quadrature sets in the solution of the second-order, multi-dimensional $S_{N}$ neutron transport equations. The newly generated quadrature sets by this method substantially mitigate ray effects and can be used in the same manner as the conventional quadrature sets are used. The discrete-ordinates and the piecewise-constant approximations are applied to both the first-order Boltzmann and the second-order form of neutron transport equations in treating angular variables. The result is that the mitigation of ray effects is only achieved by the piecewise-constant method, in which new angular quadratures are generated by integrating angle variables over the specified region. In other sense, the newly generated angular quadratures turn out to decrease the contribution of mixed-derivative terms in the even-parity equation that is one of the second-order neutron transport equation. This result can be interpreted as the entire elimination or substantial mitigation of ray effect are possible in the simplified even-parity equation which has no mixed-derivative terms.

• Journal of fish pathology
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• v.9 no.2
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• pp.157-168
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• 1996

In this study, Residue of formaldehyde and histopathological changes in formalin and neutralformalin in treated fish(Sebastes schlegeli) were observed at two different temperatures(15 and $25^{\circ}C$). Immediately after in treatment, residue of formaldehyde in formalin treated fish was show little bit higher than in neutral-formalin treated fish at $15^{\circ}C$. But, there is no difference at water temperature $25^{\circ}C$. The elimination of formaldehyde was markedly temperature-dependent. The approximated withdrawal time were 72hr and 24hr at water temperature 15 and $25^{\circ}C$. Formalin was more toxic than the neutral-formalin at the same condition. Intensity of tissues damage was increased with increasing concentration of chemical and temperature. Formalin and neutral-formalin treatments caused edema and seperation of epithelium, winding of secondary gill lamella, necrosis in the gill ; congestion and pycnosis, vacuolation in the liver ; hydropic and granulated degeneration, necrosis of epithelial cells in the proximal renal tubule ; increasing mucus cells, cracking, necrosis of epidermis and dermis in the skin tissue.

• Fire Science and Engineering
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• v.23 no.5
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• pp.143-152
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• 2009

The numerical analyses for each single simplified shaft with three type openings were carried out by using computational fluid dynamics model for the calculation of the pressure difference and the location of the neutral plane and the visualization of stack effect. As the height of shaft heighten, the pressure difference of stack effect is much deviated against the theoretical value. For the Type A models shorter than 30 m height of shaft and the Type B models longer than 30m, the simulation results for the location of the neutral plane are well agreed to the theoretical values with 5% less deviations just after the beginning of simulation (t = 10s). For the Type B models longer than 30m with multiple openings, therefore, it is possible to calculate the location of the neutral plane by using a CFD model. The phenomenon of the air flow of stack effect can be easily understood with the visualization of stack effect.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.2
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• pp.123-128
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• 2002

Fatty acid compositions of Setaria italica, Panirum miliaceum and Sorghum bicolor were determined with total lipids extracted. Total lipid content of Setaria italica, Panium miliaceum and Sorghum bicolor were 3.9%(w/w), 2.7%(w/w) and 2.3%(w/w), respectively. Total lipids were fractionated into neutral lipids, glycolipids and phospholipids by the silicic acid column chromatography. Neutral lipids were the most abundant component. Among fatty acids separated by GC, linoleic acid was determined as a major fraction in Setaria italica, Panicum miliaceum and Sorghum bicolor. Palmitic acid and oleic acid were also separated as second major components. In Setaria italica, behenic acid was separated from the phospholipid fraction and myristic acid from the neutral lipid fraction. Linolenic acid was not detected in all the samples.

• Journal of Conservation Science
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• v.21
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• pp.89-100
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• 2007

This study analyze concentration of minor and trace elements on 47 white porcelains excavated from Dudong-ri, Baekryeon-ri, Sachon-ri kilns in Gyeonsangnam-do by NAA(neutron activation analysis) and try to classify the provenance and characteristics according to the analytical result. Each kilns are divided into the group by PCA(principal component analysis) and LDA(linear discrimination analysis) using 17 elements; Ba Ce, Co, Cr, Cs, Dy, Eu, Hf, La Lu, Rb, Sc, Sm, Ta, Th, V, Yb. The contribution elements are Dy, Sm, La, Ce, Lu, Sc. And soft and hard white porcelains are similar with the chemical composition of the use materials therefore the difference of the chemical composition not confirmed a cause. The analytical results of the fine(I) and poor(II) quality white porcelains presume the difference of the povenance of clay materials or the poduction process such as difference purify and additive materials.

• Electric Engineers Magazine
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• v.253 no.9
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• pp.27-33
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• 2003

기체분자는 보통상태에서는 전기적으로 중성이다. 그러나 기체 분자가 운동에너지를 가지고 있는 다른 원자나 전자 등과 충돌하게 되면 기체 분자내의 전자가 에너지를 흡수하여 여기나 전리하게 된다. 여기나 전리의 상태는 불안정한 상태이므로 순간적으로 안정상태로 복귀하는데 이 때의 에너지차가 빛으로 방출된다. 이와 같이 온도방사와는 달리 냉광으로 발광하는 현상을 루우미네슨스라고 한다

• Journal of the Korean Vacuum Society
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• v.18 no.3
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• pp.186-196
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• 2009

Since it is difficult to extract a high flux ion beam directly at an energy of hyperthermal range ($1{\sim}100\;eV$), especially, lower than 50 eV, the ions should be neutralized into neutral particles and extracted as a neutral beam. A plasma source required to generate and efficiently transport high flux hyperthermal neutral beams should be easily scaled up and produce a high ion density (${\ge}10^{11}\;cm^{-3}$) even at a low working pressure (${\le}$ 0.3 mTorr). It is suggested that the required plasma source can be realized by Electron Cyclotron Resonance (ECR) plasmas with diverse magnetic field configurations of permanent magnets such as a planar ECR plasma source with magnetron field configuration and cylindrical one with axial magnetic fields produced by permanent magnet arrays around chamber wall. In both case of the ECR sources, the electron confinement is based on the simple mirror field structure and efficiently enhanced by electron drifts for producing the high density plasma even at the low pressure.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.3
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• pp.236-245
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• 2016

Because microalgae represent high growth rate than terrestrial plants, and it can accumulate significant lipid and carbohydrate content, and other bioactive compounds such as carotenoid and polyphenol in their body, it has been considered as one of the promising resources in bio-energy, and other industries. Although many studies has been performed about the microalgae-derived biochemical accumulation under various abiotic conditions such as different temperatures, salinities and light intensities, the studies about simultaneous effect of those parameters has rarely been performed. Therefore, this study focused on evaluation of simultaneous effect of different salinity (10, 30, 50 psu) and temperatures (20, 25, $30^{\circ}C$) on the changes of biomass, lipid, starch and photosynthetic pigment accumulation. As results, the highest growth rate was achieved at $30^{\circ}C$ and 30 psu in the both algal cultures, and the photosynthetic pigment, chlorophyll a and total carotenoid content, were increased in a temperature-dependent manner. The accumulation of lipid and starch contents exhibited different aspects under different combinations of temperature and salinity. From the results, it is suggested that the changes of microalgal lipid and starch accumulation under different salinities may be affected by the different temperatures.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.425.1-425.1
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• 2016

고온의 플라즈마를 긴 펄스 및 장시간 연속운전 유지기술 개발 및 연구를 위해서는 플라즈마는 더욱 가열되어야 하고, 고온 고밀도의 플즈마 상태를 유지시켜야 한다. 이러한 고성능 플라즈마 개발은 향후 핵융합 에너지의 상용화를 위한 절대필수적 기반기술이다. 현재 KSTAR 토카막에서는 플라즈마를 가열하기 위한 장치들 중 하나로서, 출력 6 MW 급의 중성입자빔을 입사하는 NBI (Neutral Beam Injection) 가열장치가 설치 운영 중에 있다. 이 NBI 가열장치는 진공환경에서 고온, 고압, 고전압 방전 및 수냉 등이 작동 및 운전되고 있기 때문에, 구성 부품 들의 미세한 구조적 결함에도 장치의 치명적 failed로 이어질 수 있다. 이번 연구에서는 NBI 가열장치의 특성상 극한 운전 환경에 있는 진공용기 부품 중 하나 인 빔인출을 위한 가속 그리드 (accelerating grid)의 구조적 손상및 결함 여부를 고속중성자 이미지 기법을 적용하여 내부를 투시 진단하였다. 가속 그리드는 copper로 제작되었고, 빔인출을 위한 원형의 구멍과 냉각관을 가진 평면판 형태로 되었다. 본 연구에서 내부투시 및 진단할 수 있는 고속중성자 이미징 기법의 적용으로 진공용기 부품 및 장치의 구조적 결함 및 손상 여부를 판단 가능하다는 연구 결과를 얻었다.