• Ocean and Polar Research
• /
• 제25권1호
• /
• pp.89-106
• /
• 2003

Analyses of tidal observations and a numerical model of the $M_2$ and $M_4$ tides in the Uldolmok waterway located at the southwestern tip of the Korean Peninsula are described. This waterway is well known fer its strong tidal flows of up to more than 10 knots at the narrowest part of the channel. Harmonic analysis of the observed water level at five tidal stations reveals dramatic changes in the amplitude and phase of the shallow water constituents at the station near the narrowest part, while survey results show a decreasing trend in local mean sea levels toward the narrow section. It was also observed that the amplitudes of semi-diurnal constituents, $M_2$ and $S_2$ are diminishing toward the narrowest part of the waterway. Two-dimensional numerical modeling shows that the $M_2$ energy flux is dominated by the component coming from the eastern boundary. The $M_2$ energy is inward from both open boundaries and is transported toward the narrow region of the channel, where it is frictionally dissipated or transferred to other constituents due to a strong non-linear advection effect. It is also shown that the $M_4$ generation is strong around the narrow region, and the abrupt decrease in the M4 amplitude in the region is due to a cancellation of the locally generated M4 with the component propagated from open boundaries. The superposition of both propagated and generated M4 contributions also explains the discontinuity of the M4 phase lag in the region. The tide-induced residual sea level change and the regeneration effect of the $M_2$ tide through interaction with $M_4$ are also examined.

• 대한화학회지
• /
• 제44권6호
• /
• pp.541-546
• /
• 2000

리간드 증감 유발 형광법을 이용하여 Tb(III)-L-dopa (L-3,4-dihydroxyphenyl alanine) 착이온의 방출세기를 측정함으로써 수용액 중의 L-dopa를 정량하는 방법에 대하여 연구하였다. 들뜸파장, pH, 보조 형광증가제의 선택, Tb(III) 이온의 농도, 보조 형광증가제로 사용된 Lu(III) 이온의 농도 및 방출파장의 방출세기에 대한 영향을 조사하였다. 보조 형광증가제로서 Lu(III) 이온을 첨가하였을때 Tb(III) 이온의 방출세기가 현저히 증가함을 관찰하였고, L-dopa의 검출한계를 낮출 수 있었다. 보조 형광증가제를 첨가하지 않았을 경우에 L-dopa 검정곡선의 직선감응범위는 들뜸파장, pH 및 Tb(Ⅲ) 이온의 농도가 각각 300 nm, 8.0 및 $1.0{\times}10^{-4}$ M였을때, $5.0{\times}10^{-7}$ M~$1.0{\times}10^{-4}$ M였다. 이 조건에서의 검출한계는 $4.0{\times}10^{-8}$ M였다. 보조 형광증가제를 첨가하였을 경우에는 들뜸파장, pH, Tb(III) 이온의 농도, 보조 형광증가제로 사용된 Lu(III) 이온의 농도 및 방출파장이 각각 300 nm, 8.5, $1.0{\times}10^{-5}$ M, $1.0{\times}10^{-5}$ M 및 545 nm였을 때, 직선감응범위가 1.0×$10^{-8}$ M~2.0{\times}10^{-4}$ M였고, 이 때의 검출한계는 $1.0{\times}10^{-9}$ M였다.

• 호남수학학술지
• /
• 제31권4호
• /
• pp.497-504
• /
• 2009

We introduce the concepts of M-preclosed graph and M$^*$-preopen mapping on spaces with minimal structures and investigate some properties of M$^*$-preopen mapping. We also investigate the relationships between M-precontinuous mappings and several types of m-compactness.

• 대한환경공학회지
• /
• 제32권1호
• /
• pp.33-46
• /
• 2010

본 연구는 광분해 산화공정으로 난분해성 물질인 N-Nitrosodimethylamine (NDMA)인 제거 및 부산물 생성 특성을 파악하기 위한 3개의 독립변수 (자외선 강도($X_1:\;1.5{\sim}4.5\;mW/cm^2$, 초기 NDMA 농도($X_2:\;100{\sim}300\;uM$), pH(X3:3~9))와 4개의 종속변수(NDMA 제거율($Y_1$), dimethylamine (DMA) 생성농도($Y_2$), dimethylformamide (DMF) 생성농도($Y_3$) 및 $NO_2$-N 생성농도($Y_4$))로 구성된 박스-벤켄 설계를 이용한 실험계획을 적용시켜 예측 모델과 광분해 산화 최적조건을 수립하였다. 실험결과 2시간 광분해 후 NDMA는 거의 완전히 제거되었으며 DMA, DMF와 $NO_2$-N은 NDMA 광분해와 동시에 부산물로 생성되었다. 광분해 최적의 조건을 얻기 위해 정준분석을 수행하여 최적 점 (반응값, 독립변수 조건)과 예측반응모델을 수립한 결과, 다음과 같은 결과를 얻었다 ($Y_1=117+21X_1-0.3X_2-17.2X_3+{2.43X_1}^2+{0.001X_2}^2+{3.2X_3}^2-0.08X_1X_2-1.6X_1X_3-0.05X_2X_3$ ($R^2$ = 96%, Adjusted $R^2$ = 88%)와 99.3% ($X_1:\;4.5\;mW/cm^2$, $X_2:\;190\;uM$, $X_3:\;3.2$), $Y_2=-101+18.5X_1+0.4X_2+21X_3-{3.3X_1}^2-{0.01X_2}^2-{1.5X_3}^2-0.01X_1X_2-0.07X_1X_3-0.01X_2X_3$ ($R^2$= 99.4%, 수정 $R^2$ = 95.7%)와 35.2 uM ($X_1:\;3\;mW/cm^2$, $X_2:\;220\;uM$, $X_3:\;6.3$), $Y_3=-6.2+0.2X_1+0.02X_2+2X_3-{0.26X_1}^2-{0.01X_2}^2-{0.2X_3}^2-0.004X_1X_2+0.1X_1X_3-0.02X_2X_3$ ($R^2$= 98%, 수정 $R^2$ = 94.4%)와 3.7 uM ($X_1:\;4.5\;mW/cm^2$, $X_2:\;290\;uM$, $X_3:\;6.2$), $Y_4=-25+12.2X_1+0.15X_2+7.8X_3+{1.1X_1}^2+{0.001X_2}^2-{0.34X_3}^2+0.01X_1X_2+0.08X_1X_3-3.4X_2X_3$ ($R^2$= 98.5%, 수정 $R^2$ = 95.7%)와 74.5 uM ($X_1:\;4.5\;mW/cm^2$, $X_2:\;220\;uM$, $X_3:\;3.1$). 반응표면분석법 중 하나인 박스-벤켄법은 UV 광분해에 의한 NDMA 분해 및 부산물 생성에 대한 통계학적 및 수학적인 결과 및 최적의 운전조건을 제시하였다. 예측모델의 검정을 통하여 박스-벤켄법은 매우 높은 신뢰성을 보였다.

• 한국산림과학회지
• /
• 제74권1호
• /
• pp.56-60
• /
• 1986

GD 기본(基本) 배지(培地)에 서로 다른 생장조절물질(生長調節物質)을 첨가(添加)한 4 가지 배지(培地)에 잣나무 배(胚)에서 유래(由來)한 Callus를 1년(年) 6개월간(個月間) 배양(培養)시켜 염색체수(梁色體數) 변이(雙異)를 조사(調査)하였다. 그 결과(結果) $0.1mg/{\ell}$와 NAA $0.1mg/{\ell}$에 2, 4-D $0.1mg/{\ell}$를 첨가(添加)한 배지(培地) 즉(卽) Auun 단독(單獨) 및 배합(培合) 처리(處理)한 배지(培地)에서는 2n 비율(比率)이 각각(各各) 29%와 17%로 낮게 나타났다. 그러나 Auxin 과 Cytokinin 을 종합(複合) 처리(處理)한 배지(培地) 즉(卽) 2, 4-D $0.1mg/{\ell}$와 BAP $0.1mg/{\ell}$에서는 52 %, 2, 4-D $0.1mg/{\ell}$와 Kinetin $0.1mg/{\ell}$에서는 36 %로써 비교적(比較的) 높은 빈도(頻度)로 2n 세포(細胞)가 나타났다. 2n 세포(細胞)의 빈도(頻度)는 기관분화(器官分化)와 상관(相關)이 높은 것으로 생각 할 수 있었다.

• Journal of Radiation Protection and Research
• /
• 제33권1호
• /
• pp.41-46
• /
• 2008

[ $^{99m}Tc$ ]를 주사할 때 시술자의 손가락에 흡수되는 방사선량을 예측하기 위해, GEANT4를 이용하여 초당 370 MBq의 방사능량을 가지는 0.4 mL 체적의 $^{99m}Tc$ 선원을 대상으로 각 손가락에 대한 등가선량을 구하였다. 시뮬레이션 결과, 오른손 엄지($0.29\;{\mu}Sv{\cdot}sec^{-1}$), 검지($1.19\;{\mu}Sv{\cdot}sec^{-1}$), 중지($1.07\;{\mu}Sv{\cdot}sec^{-1}$), 왼손 엄지($4.36\;{\mu}Sv{\cdot}sec^{-1}$), 검지($3.37\;{\mu}Sv{\cdot}sec^{-1}$)의 등가선량을 얻을 수 있었다. 이와 같은 계산 결과는 $^{99m}$Tc 주입시 시술자의 손가락에 흡수되는 선량을 예측할 수 있는 유용한 기초자료로 활용될 수 있을 것이다.

• 한국전기전자재료학회논문지
• /
• 제14권8호
• /
• pp.663-669
• /
• 2001

Spinel LiM $n_2$ $O_4$ and LiM $n_{1.9}$M $g_{0.1}$ $O_4$ power was synthesized with solid-state method by calcining the mixture of LiOH.$H_2O$, Mn $O_2$ and MgO at 80$0^{\circ}C$ for 36 h in an air atmosphere. To investigate the effect of temperature on he cycle performance of cathode material during cycling, charge-discharge experiments and ac impedance measurement were performed. Initial discharge capacity was gradually increased with the increase of charge-discharge temperature. Discharge capacity at high temperature was suddenly decreased during cycling. On the other hand, discharge capacity at low temperature was almost constant during cycling. It confirmed that Mn dissolution is serious at high temperature than at low temperature. LiM $n_2$ $O_4$ and LiM $n_{1.9}$M $g_{0.1}$ $O_4$ showed the best capacity and stability at room temperature.ure.ure.

• The Korean Journal of Physiology and Pharmacology
• /
• 제25권2호
• /
• pp.159-166
• /
• 2021

Nicotinamide adenine dinucleotide phosphate oxidases (NOXs) are the major enzymatic source of reactive oxygen species (ROS). NOX2 and NOX4 are expressed in the heart but its role in hypoxia-induced atrial natriuretic peptide (ANP) secretion is unclear. This study investigated the effect of NOX on ANP secretion induced by hypoxia in isolated beating rat atria. The results showed that hypoxia significantly upregulated NOX4 but not NOX2 expression, which was completely abolished by endothelin-1 (ET-1) type A and B receptor antagonists BQ123 (0.3 μM) and BQ788 (0.3 μM). ET-1-upregulated NOX4 expression was also blocked by antagonists of secreted phospholipase A2 (sPLA2; varespladib, 5.0 μM) and cytosolic PLA2 (cPLA2; CAY10650, 120.0 nM), and ET-1-induced cPLA2 expression was inhibited by varespladib under normoxia. Moreover, hypoxia-increased ANP secretion was evidently attenuated by the NOX4 antagonist GLX351322 (35.0 μM) and inhibitor of ROS N-Acetyl-D-cysteine (NAC, 15.0 mM), and hypoxia-increased production of ROS was blocked by GLX351322. In addition, hypoxia markedly upregulated Src expression, which was blocked by ET receptors, NOX4, and ROS antagonists. ET-1-increased Src expression was also inhibited by NAC under normoxia. Furthermore, hypoxia-activated extracellular signal-regulated kinase 1/2 (ERK1/2) and protein kinase B (Akt) were completely abolished by Src inhibitor 1 (1.0 μM), and hypoxia-increased GATA4 was inhibited by the ERK1/2 and Akt antagonists PD98059 (10.0 μM) and LY294002 (10.0 μM), respectively. However, hypoxia-induced ANP secretion was substantially inhibited by Src inhibitor. These results indicate that NOX4/Src modulated by ET-1 regulates ANP secretion by activating ERK1/2 and Akt/GATA4 signaling in isolated beating rat hypoxic atria.

• Bulletin of the Korean Chemical Society
• /
• 제32권10호
• /
• pp.3682-3686
• /
• 2011

The electrochemical properties of lithium-sulfur batteries with binary electrolytes based on DME and DOL, TEGDME and DOL mixed solvent containing $LiClO_4$, LiTFSI, and LiTF salts were investigated. The ionic conductivity of 1M LiTFSI and $LiClO_4$ electrolytes based on TEGDME and DOL increased as the volume ratio of DOL solvent increased, because DOL effectively reduces the viscosity of the above electrolytes medium under the same salts concentration. The first discharge capacity of lithium-sulfur batteries in the DME and DOL-based electrolyte followed this order: LiTFSI (1,000 mAh/g) > LiTF (850 mAh/g) > $LiClO_4$ (750 mAh/g). In case of the electrolyte based on TEGDME and DOL, the first discharge capacity of batteries followed this order: $LiClO_4$ (1,030 mAh/g) > LiTF (770 mAh/g) > LiTFSI (750 mAh/g). The cyclic efficiency of lithium-sulfur batteries at 1M $LiClO_4$ electrolytes is higher than that of batteries at other lithium salts-based electrolytes. Lithium-sulfur battery showed discharge capacity of 550 mAh/g until 20 cycles at all electrolytes based on DME and DOL solvent. By contrast, the discharge capacity of batteries was about 450 mAh/g at 1M LiTFSI and LiTF electrolytes based on TEGDME and DOL solvent after 20 cycles.

• Preventive Nutrition and Food Science
• /
• 제15권2호
• /
• pp.105-112
• /
• 2010

Thirty-four strains of Lactobacillus species were isolated from soil and eight of these isolates (M1-4 and P1-4) were capable of growing on red ginseng agar. The M1 and P2 strains were determined to be L. plantarum and other strains (M2, M3, M4, P1, P3 and P4) were determined to be L. brevis. Fermentation of red ginseng extract (RGE) with strains M1, M2, P2 and P4 resulted in a low level of total carbohydrate content (174.3, 170.0, 158.8 and 164.8 mg/mL, respectively). RGE fermented by M3 showed a higher level of uronic acid than the control. The polyphenol levels in RGE fermented by M1, P1 and P2 (964.9, 941.7 and $965.3\;{\mu}g/mL$, respectively) were higher than the control ($936.8\;{\mu}g/mL$). Total saponin contents in fermented RGE (except M1) were higher than the control. RGE fermented by M2 and M3 had the highest levels of total ginsenosides (31.7 and 32.7 mg/mL, respectively). The levels of the ginsenoside Rg3 increased from 2.6 mg/mL (control) to 3.0 mg/mL (M2) or 3.1 mg/mL (M3). RGE fermented by M2 and M3 also had the highest levels of Rg5+Rk1 (7.7 and 8.3 mg/mL, respectively). Metabolite contents of ginsenoside (sum of CK, Rh1, Rg5, Rk1, Rg3 and Rg2) of M2 (13.0 mg/mL) and M3 (13.9 mg/mL) were also at a high level among the fermented RGE. Protopanaxadiol and protopanaxatriol content of ginsenoside of M2 (10.9 and 5.4 mg/mL, respectively) and M3 (11.0 and 5.7 mg/mL, respectively) were at higher levels than other fermented RGE.