• Journal of Radiation Protection and Research
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• v.22 no.2
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• pp.119-125
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• 1997

PHWR achieves high neutron economy by adopting heavy water as its moderator and coolant. On the other hand it permits much tritium generation, compared to LWR, due to the neutron capture reaction of deuterium in heavy water. Meanwhile in the reactor core, $^3He formed as the result of-decay of tritium, captures a thermal neutron and transforms to tritium again. The existing calculation models on tritium generation in PHWR neglect the contribution of $^3He$ in both moderator and coolant due to its relatively low solubility. However the neutron capture cross-section of $^3He$ is almost $1.6{\times}10^7$ times as large as that of deuterium. That means that the dissolved amount of 0.03 ppm of $^3He$ in heavy water is enough to generate the same amount of tritium as that generated by the deuterium of total heavy water in the system. This study dealt with the contribution of $^3He$ to tritium generation. As a sample case, the contribution of $^3He$ to the tritium generation in Wolsong #1 was evaluated and compared to the measured values. According to the result of this study, it is concluded that $^3He$ in coolant contributes very much to the tritium generation but that in moderator shows negligible effects due to the low solubility and $^4He$ cover gas. At the beginning of the plant operation, the contribution of $^3He$ is slightly greater than the measured value but agrees well with the measured as the operating time increases.

• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.114-118
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• 2000

The paper presents the effects of outpLlt-coLLpling power and small SIgnal gain of a He-Se+ laser by discharge of either $^4He$ or $^3He$. A quartz plane-plate was installed to outpLlt-coLlple the laseI beam from the resonator in the eAperimental setup. The result shows tbat compared with those of ~He, tbe outPLlt-coupling power and small-signal gain of $^4He$ increase in the most of the lines. EspeCIally, the small-signal gain of $^3He$ for the strong lines (497.6 nm, 499.3 nm, 506.9 urn, 5176 nm, 522.8 mn, 530.5 nm) lies 25% higher than Ulat of 4He, and the output-coupling power doubles oubles

• Journal of the korean society of oceanography
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• v.36 no.1
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• pp.19-26
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• 2001

The biological pump is one of the important pumping mechanisms absorbing CO$_2$ from the atmosphere into the ocean and can be quantified by estimating new production. New production in the open ocean mostly depends on the supply of nitrate from the water below the mixed layer. While nitrate is affected by many biological processes, the helium isotope ($^3$He) is inert and has very simple physical properties. Using the $^3$He flux and the relation between $^3$He and NO${_3}\;{^-}$- within the thermocline, the nitrate flux supporting new production was estimated in the southern East Sea. The average ${\delta}^3$He within the mixed layer was -14$%_o$ and -l5.4$%_o$ in the winter and autumn, respectively. Through the year excess $^3$He occurs in the mixed layer except for a slight depletion of -17$%_o$ in summer. The $^3$He flux of 13$%_o$md$^{-1}$ associated with the concentration gradient at the air-sea interface was calculated from the product of the piston velocity and the excess $^3$He. Tritium decay within the mixed layer could support only 2$%_o$md$^{-1}$ of the flux. Thus, the remaining 11$%_o$md^{-1}$ could be attributed to the flux of tritiugenic $^3$He from the water below the mixed layer. Nitrate and $^3$He were positively correlated within the thermocline layer with the slope of 0.21 ${\mu}$mol kg$^{-1}$ $%_o\;^{-1}$. The annual nitrate flux estimated from the upward flux of $^3$He and the NO$_{3}\;{^-}$-$^3$He relation was 0.8${\pm}$0.2 mol(N) m$^{-2}$yr$^{-1}$. This flux corresponds to an annual new production of 64 g(C) m$^{-2}$yr$^{-1}$, which is consistent with that in the north-west Pacific.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.159-159
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• 2010

펄스 직류 전원 $BCl_3$/He 플라즈마를 사용하여 GaAs의 건식 식각을 연구하였다. 공정 변수는 가스 유량 (0~100% $BCl_3$ in $BCl_3$/He), 펄스 파워 ($450{\sim}600\;{\nu}$), 펄스 주파수 (100~250 KHz), 펄스 시간 ($0.4{\sim}1.2\;{\mu}s$)이었다. 식각 공정 후 식각률, 포토레지스트에 대한 식각 선택도, 표면 거칠기는 표면 단차 측정기를 이용하였다. 식각 공정 동안 플라즈마 광 특성 분석은 광학 발광분석기 (Optical emission spectroscopy)를 사용하였다. 실험 후 주사 전자 현미경을 이용, 식각 후 시료의 단면과 표면을 관찰하였다. 실험 결과에 의하면 1) 펄스 파워, 주파수, 시간을 고정 ($500\;{\nu}$, $0.7\;{\mu}s$, 200 KHz)하고 10% He 가스가 혼합되어 있는 조건에서 GaAs의 식각률이 순수한 $BCl_3$를 사용한 것보다 높았다. 이를 통해 식각 공정에서 일정량 이하의 He 혼합은 GaAs 식각률을 증가시키는 시너지효과가 있음을 알 수 있었다. 2) 그러나 약 20% 이상의 He 가스의 혼합은 GaAs의 식각 속도를 저하시켰다. 3) 10% He (9 sccm $BCl_3/1$ sccm He), 200 KHz 펄스 주파수, $0.7\;{\mu}s$ 펄스 시간의 조건에서 펄스 파워가 증가함에 따라 GaAs의 식각률 또한 선형적으로 증가하였다. 4) 특히, $600\;{\nu}$의 파워에서 식각률은 ${\sim}0.5\;{\mu}m/min$로 가장 높았다. 5) 표면 단차 측정기와 전자현미경을 이용하여 식각한 GaAs를 분석한 결과 10% He이 혼합되어 있는 조건에서는 우수한 수직 측벽과 매끈한 표면 (RMS roughness <1 nm)을 관찰할 수 있었다. 6) 10% He이 혼합된 $BCl_3$/He 펄스 직류 플라즈마 식각 후 XPS 분석결과에서도 기준 샘플과 비교하였을 때, 공정 후의 GaAs 표면이 화학적으로 깨끗하며 잔류물이 거의 검출되지 않았다. 위의 결과를 정리하였을 때, 펄스 직류 $BCl_3$/He 플라즈마는 GaAs의 식각에서 매우 우수한 공정 결과를 나타내었다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.2
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• pp.16-22
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• 2004

The paper presents the effects of output-coupling power and small signal gain of selenium vapour multiline laser by discharge of either to $^4$He or $^3$He. The purity of the He gas was improved with a special He-fille.. The result shows that compared with those of $^4$He, the output-coupling power and small-signal gain of $^3$He increase in the most of the lines. Especially, the small-signal gain of $^3$He for the strong lines (497.6 nm, 499.3 nm, 506.9 nm, 517.6 nm, 522.8 nm, 530.5 nm) lies about 30% higher than that of $^4$He, and the output-coupling power from doubles to triples.

• Journal of the Korean Applied Science and Technology
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• v.35 no.2
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• pp.389-398
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• 2018

This study was to investigate the antioxidant and anti-amyloid activities of the extract (KP-HE) from Kalopanax pictus (KP) fermented with Hericium erinaceum (HE) mycelium. Antioxidant activity was evaluated based on 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical(ABTS) scavenging assays. In all assays, the extracts from KP, HE and KP-HE had the potential for antioxidant activities. However, antioxidant activity of KP-HE significantly scavenged DPPH radical as compared to the KP and HE. The result suggested that the antioxidant component was increased in the process of KP fermented with HE. KP-HE was shown to significantly inhibite peroxyl radical-mediated DNA strand breakage whereas KP and HE did not inhibit DNA strand breakage. The aggregation of the amyloid-${\beta}$ ($A{\beta}$) peptide is involved in the pathological process of Alzheimer's disease(AD). In this study, the effects of KP, HE and KP-HE on the aggregation of $A{\beta}_{1-42}$ were investigated. KP and HE had little effect on $A{\beta}$ aggregation and KP-HE effectively inhibited $A{\beta}$ aggregation. KP-HE effectively inhibited $A{\beta}$ induced cell death and significantly increased of the 20.3% cell survival at $300{\mu}g/mL$ concentration. KP-HE also decreased intracellular reactive oxygen specie levels in $A{\beta}$-treated cells. The results suggested that KP-HE had antioxidant and anti-amyloid activities. Therefore, KP-HE could potentially be used as a valuable functional food ingredient to prevent neurodegenerative disorders such as AD.

• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.190-193
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• 2000

ab initio calculations are presented for M-Rg and M-Rg2 (M=Li, Na, Rg=He, Ar) van der Waals clusters.InternucIear distances and binding energies of LiHe, LiAr and NaAr obtained by all-electron MP2(6-311++G(3df,3pd)) method are in good agreement with experimental values. Calculated properties of LiHe$_2$, LiAr$_2$, NaHe$_2$ and NaAr$_2$ are also reported.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.415-422
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• 2016

In this research, the total polyphenol and flavonoid contents in the hot water extract (HE) and methanol extract (ME) of the Coriolus versicolor fruiting body and their partial bioactivities were investigated from March, 2015 to February, 2016. For the analysis of the data, the software used was SPSS 2.0. The results indicate that the total polyphenol content in the HE (129.60 mg/dl) was 85,8 mg/dl higher than that in the ME (43.80 mg/dl). The total flavonoid content in the HE (30.50 mg/dl) was 9.5 mg/dl higher than that in the ME (20.90 mg/dl). The DPPH scavenging activities of the HE and ME at a concentration of 3 mg/ml were 41.03% and 16.36% higher than those at a concentration of 1 mg/ml. The tyrosinase inhibitory activities of the HE and ME at a concentration of 3 mg/ml were 8.29% and 10.32% higher than those at a concentration of 1 mg/ml. The elastase inhibitory activities of the HE and ME at a concentration of 3 mg/ml were 3.12% and 21.53% higher than those at a concentration of 1 mg/ml. The collagenase inhibitory activities of the HE and ME at a concentration of 3 mg/ml were 5.44% and 4.07% higher than those at a concentration of 1 mg/ml. In conclusion, these two kinds of extracts are judged to be useful as skin wrinkle relaxants, due to their anti-oxidative and bioactive functions.

• Journal of the Korean Chemical Society
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• v.36 no.3
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• pp.376-382
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• 1992

Liquid helium is an exciting subject for the study of thermodynamic and transport properties because of its remarkable properties. The viscosity of liquid helium exhibits the abnormal behavior compared to other ordinary liquid. Below the $\lambda$ point liquid $^4He$ becomes superfluid, and it is obviously quite a different phenomenon from the change of liquid $^3He$. The brake theory of viscosity proposed by authors is successfully applied to liquid $^3He$, liquid $^4He$, dense gas and 4He with adjustable parameter $V_s$. The calculation results are satisfactory compared with the observed values.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1535-1542
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• 2009

To find the new use of Korean ginseng and mushroom, crude polysaccharides were prepared from submerged cultures of Hericium erinaceum in the medium supplemented with Korean ginseng extracts. When we fractionated crude polysaccharides (HE-GE-CP-1, 3, and 5) from hot-water extracts of submerged cultures of H. erinaceum with ginseng extracts (1%, 3%, and 5% addition of total medium), the yields of HE-GE-CP-1, 3, and 5 were identified at 5.7, 5.1, and 4.8%, respectively. Among crude polysaccharide fractions, HE-GE-CP-5 was significantly higher (1.89-fold of the saline control) than those of HE-GE-CP-1 (1.64-fold) or HE-GE-CP-3 (1.76-fold) on mitogenic activity of splenocytes. HE-GE-CP-5 also had the more potent bone marrow cell proliferation (1.83-fold) rather than HE-CP or HE-GE-CP-1 or HE-GE-CP-3 (1.59- or 1.44- or 1.69-fold, respectively), and anti-metastatic activity as anti-cancer effect showed the highest prophylactic value (72.4% inhibition of tumor control) in 5% supplementation of ginseng extract. However, the lysosomal phosphatase of macrophage was significantly stimulated after HE-GE-CP-3 treatment (2.03-fold). In addition, the immunostimulating and anti-metastatic crude polysaccharide, HE-GE-CP-5, contained mainly neutral sugars (63.2%) with considerable amounts of uronic acid (19.3%) and a small amount of proteins (8.8%). HE-GE-CP-5 can stimulate immune system to inhibit tumor metastasis, and its anti-tumor metastasis may be associated with macrophages, splenocytes and Peyer's patch cells activation.