• 태양에너지
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• 제14권2호
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• pp.75-90
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• 1994

본 연구에서는 한 단역벽에 한개의 등온사각빔이 부착된 2차원 수평과 수직단열채널에서의 열 에너지 이송에 대하여 수치해석적으로 연구하였다. 빔의 형상비는 H/B=$0.25{sim}4$, Reynolds수는 Re=$50{\sim}500$ 그리고 Grashof수는 Gr=$0{\sim}5{\times}10^4$범위에서 해를 구하였다. Re=100인 경우 수평과 수직채널에서 빔의 평균 Nusselt수는 Gr=0에서는 같은 값을 나타내며, Grashof수가 증가할수록 증가하였으며, 형상비가 증가할수록 감소하였다. Gr=$10^4$, Re=100인 경우 수평과 수직채널에서 빔의 평균 Nusselt수는 수직채널이 수평채널에 비하여 $0.25{\leq}H/B<1.1$에서는 높게, $1.1{\leq}H/B{\leq}4.0$에서는 낮게 나타났다. Re=100, $0<Gr{\leq}5{\times}10^4$인 경우 수평과 수직채널에서 빔의 평균 Nusselt수 분포는 수직채널이 수평채널에 비하여 H/B=0.25에서는 높고 H/B=4.0에서는 낮으며 H/B=1.0에서는 다소 높게 나타났다. 실험으로 얻은 간섭사진의 등온선과 수치계산으로 구한 등온선이 비교적 잘 일치하여 수치해석의 타당성을 입증하였다.

• Korean Journal of Acupuncture
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• 제28권3호
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• pp.73-83
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• 2011

Objectives : The purpose of this study is to investigate anti-allergic effects of Glycyrrhizae Radix(GR) pharmacopuncture and GR extract. Methods : In vivo, animals were gotten GR pharmacopunctures at both sides of ST36s three times for 5 days. Then, we investigated anti-DNP IgE-induced passive cutaneous anaphylaxis of Sprague Dawley rats. In vitro, we measured cell viability, ${\beta}$-hexosaminidase release, and the secretion of interleukin-4(IL-4) and tumor necrosis factor-alpha(TNF-${\alpha}$) in RBL-2H3 cells after treatment of various concentrations of GR extract. Results : In vivo, we observed inhibition of passive cutaneous anaphylaxis after GR pharmacopuncture treatments at both sides of ST36s and optional points. In vitro, GR extract treatments did not affect cell viability, but inhibited ${\beta}$-hexosaminidase release and the secretion of IL-4 and TNF-${\alpha}$. Conclusions : These results suggest that GR pharmacopuncture and GR extract should be beneficial in the inhibition of allergic inflammatory response.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1999년도 한국생물과학협회 학술발표대회
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• pp.150.2-150
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• 1999

To investigate the weathering soil buffering capacities of the artificial acidic precipitation, the weathering soils and their leachate solutions were sampled from the host rocks(granite;GR, rhyolite;RH, gabbro;GA, basalt;BA, two serpentinite;SE1, SE2 and limestone;LI) and analyzed for pH and chemical properties. 1n the soil pH of the GR and RH ,the acidic rocks, were 5.02 and 5.95, respectively. And the GA and BA, basic rocks, were 6.52 and 7.57. The SE1 and SE2 were 8.90 and 8.89. While the LI was 7.84. These results means the typical soil pH properties by host rocks. After the artificial acidic precipitation input 5OOml, the average changes of soil leachate solutions treated by pH levels(pH 5.0, 4.0 and 3.0), were pH 5.73, 5.00 and 4.40. in GR soil, and pH 6.19, 5.99 and 5.57 in RH. GA were pH 6.31, 6.04 and 5.86, BA were pH 7.05, 6.85 and 6.56 and SE1 were pH 8.31, 8.26 and 7.71. SE2 were pH 8.29, 8.24 and 7.96. LI were pH 7.55, 7.46 and 6.79. The soil leachate pHs from volcanic rocks were higher than those from the plutonic rocks and GR soils showed greater response than other soils. With increasing 100ml input-solution, the soil leachate pHs were mainly decreased. Cation concentrations, CEC, EC and total nitrogen concentrations of RH and BA soils, the volcanic rocks, were higher than those of GR and GA soil, the plutonic rocks. On the contrary, Al concentrations of the GR and GA soils were higher than those of RH and BA soils, partly because of high quartz content in GR and Al content in the biotite and plagioclase in GA.

• 설비공학논문집
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• 제7권1호
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• pp.63-72
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• 1995

Convective heat transfer in a two-dimensional horizontal and vertical channel with isothermal rectangular beams attached to one adiabatic wall is investigated from the numerical solution of Navier-Stokes and energy equations. The solutions have been obtained for dimensionless beam spacings, S/L=1~4, aspect ratios of beam, H/B=0.25~4, Reynolds numbers, Re=50~1000 and Grashof numbers, $Gr=0{\sim}5{\times}10^4$. The total mean Nusselt number, Nu_T for horizontal and vertical channels shows same value at Gr=0. As Gr increases, Nu_T for horizontal channel increases, but Nu_T for vertical channel shows similar value at S/L=2, H/B=0.25, Re=100. The total mean Nusselt number for horizontal channel is higher than that for vertical channel. As H/B increases, $Nu_T$ for both channel decrease at $Gr=10^4$, Re=100.

• Carbon letters
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• 제16권4호
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• pp.233-240
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• 2015

Electrochemical synthesis was employed to prepare a novel hydroxyapatite/graphene (HAP/Gr) composite powder suitable for medical applications as a hard tissue implant (scaffold). The synthesis was performed in a homogeneous dispersion containing Na₂H₂EDTA·2H₂O, NaH₂PO₄ and CaCl₂ with a Ca/EDTA/PO₄³⁻ concentration ratio of 0.25/0.25/0.15M, along with 0.01 wt% added graphene nanosheets, at a current density of 137 mA cm⁻² and pH value of 9.0. The field emission scanning electron microscopy and transmission electron microscopy observations of the composite HAP/Gr powder indicated that nanosized hydroxyapatite particles were uniformly placed in the graphene overlay. Raman spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction confirmed graphene incorporation in the HAP/Gr powder. The electrochemically prepared HAP/Gr composite powder exhibited slight antibacterial effect against the growth of the bacterial strain Staphylococcus aureus.

• Journal of Ginseng Research
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• 제44권2호
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• pp.258-266
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• 2020

Background: Oxidative stress-induced cardiomyocytes apoptosis is a key pathological process in ischemic heart disease. Glutathione reductase (GR) reduces glutathione disulfide to glutathione (GSH) to alleviate oxidative stress. Ginsenoside Rb1 (GRb1) prevents the apoptosis of cardiomyocytes; however, the role of GR in this process is unclear. Therefore, the effects of GRb1 on GR were investigated in this study. Methods: The antiapoptotic effects of GRb1 were evaluated in H9C2 cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, annexin V/propidium iodide staining, and Western blotting. The antioxidative effects were measured by a reactive oxygen species assay, and GSH levels and GR activity were examined in the presence and absence of the GR inhibitor 1,3-bis-(2-chloroethyl)-1-nitrosourea. Molecular docking and molecular dynamics simulations were used to investigate the binding of GRb1 to GR. The direct influence of GRb1 on GR was confirmed by recombinant human GR protein. Results: GRb1 pretreatment caused dose-dependent inhibition of tert-butyl hydroperoxide-induced cell apoptosis, at a level comparable to that of the positive control N-acetyl-L-cysteine. The binding energy between GRb1 and GR was positive (-6.426 kcal/mol), and the binding was stable. GRb1 significantl reduced reactive oxygen species production and increased GSH level and GR activity without altering GR protein expression in H9C2 cells. Moreover, GRb1 enhanced the recombinant human GR protein activity in vitro, with a half-maximal effective concentration of ≈2.317 μM. Conversely, 1,3-bis-(2-chloroethyl)-1-nitrosourea co-treatment significantly abolished the GRb1's apoptotic and antioxidative effects of GRb1 in H9C2 cells. Conclusion: GRb1 is a potential natural GR agonist that protects against oxidative stress-induced apoptosis of H9C2 cells.

• 농업과학연구
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• 제30권1호
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• pp.31-40
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• 2003

충남 금산군에 위치하고 있는 고려인삼포장에 대하여 구성 모암별로 각각 흑운모화강암지역 및 천매암지역으로 분류하여 모암에 함유되어 있는 전이원소의 특성과 해당 모암별 풍화토양 및 인삼 묘포토양의 물리적 및 화학적 특성을 분석하였다. 본 고려인삼재배지에서 흑운모화강암지역의 토양은 풍화토양 및 묘포토양 공히 사질식토(Sandy clay)로 구성되어 있었으며, 천매암토양은 중식토(Heavy clay) 내지 미사질식토(Silty clay)로 구성되어 있었다. 흑운모화강암 풍화토양의 용적비중은 $1.21{\sim}1.32g/cm^3$이었고, 천매암 풍화토양은 $1.26{\sim}1.38g/cm^3$이었고, 인삼 묘포토양은 흑운모화강암토양은 $1.02{\sim}1.10g/cm^3$이었으며, 천매암 묘포토양은 $0.98{\sim}1.17g/cm^3$로 전체적으로 풍화토양보다 낮았는데, 이는 경작을 위한 토층의 경운 때문으로 사료된다. 흑운모화강암 풍화토양의 pH는 4.80이었고, 천매암 풍화토양은 5.34로 산성암인 화강암에서 더 낮게 나타났다. 흑운모화강암 묘포토양 pH는 2년 생지역이 4.39, 4년생지역이 4.40이었고, 천매암묘 포토양은 2년생지역이 5.24, 4년생지역이 5.34로 나타났으며, 이는 풍화토양의 pH 변화가 묘포토양의 pH 변화와 일치하였다. 유기물함량은 흑운모화강암 풍화토양(0.24%)보다 천매암 풍화토양(1.02%)이 높았으며, 흑운모화강암 묘포토양은 2년생지역이 0.87%, 4년생지역이 1.52%이었고, 천매암토양은 2년생지역이 2.06%, 4년생지역이 2.96%으로 천매암토양의 유기물함량이 더 높게 나타났다. 전질소 함량은 흑운모화강암 풍화토양은 259.43ppm이었고, 천매암 풍화토양은 657.22ppm이었으며, 묘포 토양은 흑운모화강암지역은 2년생지역이 588.04ppm, 4년생지역이 657.22ppm이었고, 천매암 지역은 2년생지역이 1037.72ppm, 4년생지역이 1227.96ppm이었다. 또한 질산태질소 및 암모니아 태질소의 함량은 흑운모화강암 풍화토양에서 미량 및 5.98ppm이었고, 천매암 풍화토양은 6.73ppm 및 9.94ppm이었다. 묘포토양의 경우 흑운모화강암토양은 각각 2년생지역이 223.09ppm, 26.96ppm이었고, 4년생지역이 19.46ppm, 8.23ppm이었으며, 천매암토양의 2년생지역이 각각 14.22ppm, 16.84ppm이었고, 4년생지역이 306.93ppm, 34.21ppm이었다. 이는 비료의 종류에 따라 차이가 생기지만 암모니아 태질소의 산화로 인한 질산태 질소 성분이 더 많이 축적된 것으로 나타났다. 인산함량은 흑운모화강암 및 천매암 풍화토양에서 14.41ppm 및 38.60ppm이었으며, 묘포토양은 흑운모화강암지역은 2년생지역이 46.89ppm, 4년생지역이 102.44ppm이었고, 천매암지역은 2년생지역이 147.04ppm, 4년생지역이 342.97ppm이었다. 토양 중 양이온치환용량은 흑운모화강암 풍화토양이 12.34me/100g이었고, 천매암 풍화토양이 15.40me/100g이었다. 흑운모화강암 묘포토양은 2년생지역이 15.80me/100g, 4년생지역이 7.70me/100g이었고, 천매암지역은 2년생지역이 12.14me/100g, 4년생지역이 12.83me/100g이었다. 치환성양이온($K^+$, $Ca^{2+}$, $Mg^{2+}$, $Na^+$)은 모두 풍화토양내 함량보다 묘포토양의 함량이 더 높았다. $SO_4{^2-}$ 함량은 모암별 풍화토양의 함량(화강암: 5.98ppm, 천매암: 9.94ppm)이 묘포토양(흑운모화강암 2년: 26.96ppm, 4년: 8.23ppm, 천매암 2년: 16.84ppm, 4년: 64.21ppm)에 비해 모두 낮았다.$Cl^-$ 은 풍화토양내에는 두 모암지역 모두 미량으로 존재하였으며, 묘포토양(흑운모화강암 2년: 39.06ppm, 4년: 273.43ppm, 천매암 2년: 66.41ppm, 4년: 406.24ppm)은 비료성분의 투입으로 풍화토양보다 함량이 높아진 것으로 사료된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.383-383
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• 2023

오늘날 수문학 분야에서는 유역에 대한 강우-유출 시뮬레이션을 머신 러닝(ML: Machine Learning)을 활용하여 다양한 연구를 실행하고 있다. 본 연구에서는 시간별 강우-유출 예측 모델인 GR4H(Génie Rural à 4 paramètres Horaires)를 사용하여 충주댐 유역을 대상으로 연구를 수행하였다. 유역의 속성에 따라서 모델의 성능이 어떻게 달라지는지 비교하여 특성에 맞는 모델을 알아내고. 또한 이 과정에서 기상 및 유출 데이터의 보정 길이를 가지고 어느 정도의 데이터 기간이 모델에서 좋은 성능을 보이는지 파악하였다. 뿐만 아니라 모델에 필요한 선행기간의 데이터가 있는 경우와 없는 경우를 비교하여 어떠한 차이를 보이는지, 그리고 선행기간은 얼마나 필요한지 연구를 통하여 알아냈다. 본 연구를 통하여 충주댐 유역에 대한 모델의 적용성 및 성능을 파악하고 수문 모형 구축에 제한이 있는 유역에 대해서도 사용이 가능한지 판단한다. 실험 유역의 관측 값을 모델에 입력한 후 각 모델에 해당하는 매개변수의 최적값을 찾아내는 과정을 거쳐 시뮬레이션을실 행했다. 본 연구에서 사용한 강우-유출 모델인 GR4H는 프랑스의 INRAE-Antony(Institut National de la recherche agronomique-Antony)에서 만들어진 airGR의 일종으로, 시간별 강우-유출 예측을 위해 개발된 공정 기반(process-based)의 집중적, 개념적 수문학 모델이다. 4개의 매개변수(parameter)가 있으며 이는 유역의 특정 속성을 나타낸다. GR4H를 시뮬레이션 하는 과정에서 매개변수의 최적화를 위해 적절한 보정 길이를 파악하여야 한다. 이러한 과정은 4년, 5년, 6년 등 1년씩 데이터의 양을 늘려가며 매개변수를 최적화한다. 이 과정에서 기상 및 유출 데이터의 적절한 보정 길이를 찾아낸다. 시뮬레이션을 통해 얻은 데이터를 관측 값과 비교하여 모델의 성능을 평가하고 다른 관측 값을 통해 시뮬레이션을 실행하여 검증을 거친다.

• Journal of Nuclear Fuel Cycle and Waste Technology
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• 제1권1호
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• pp.57-63
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• 2013

Natural green rust (GR) can retard the migration of anions through geological media because it has a Layer Double Hydroxyl (LDH) structure with a positive charge. In this study, the sorption behaviors of anions such as selenite ($Se(IV)O{_3}^{2-}$), selenate ($Se(VI)O{_4}^{2-}$), and iodide ($I^-$) onto green rusts with different structures, i.e., GR($Cl^-$) and GR($CO{_3}^{2-}$), were investigated by conducting batch sorption experiments in an anoxic condition. Experimental results showed that selenite was mostly sorbed onto GR($CO{_3}^{2-}$) and then partly reduced to metal selenium, Se(0). However, little selenate and iodide was sorbed onto GR($CO{_3}^{2-}$) while some iodide was sorbed onto GR($Cl^-$). It is presumed from the experimental results that the major sorption mechanism of $SeO{_3}^{2-}$ and $I^-$ onto green rusts is the anion exchange reaction with the anions existing in the interlayer of the rusts. Green rust, therefore, can play an important role in the retardation of anions migrating through deep geological environments owing to its LDH structure with a high anion exchange capacity.

• 약학회지
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• 제35권3호
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• pp.154-164
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• 1991

These experiments were conducted to investigate the effects of Glycyrrhizae Radix extract(GR) on histamine synthesis, lymphocyte blastogenesis in C57BL/6J mice splenocytes, IL-1 production, $Ca^{2+}$ uptake by macrophage-like P388D$_{1}$ cells and plaque forming cell assay against SRBC. Histamine contents, lymphocyte blastogenesis, IL-1 activity, $Ca^{2+}$ uptake and plaque forming cell were determined by enzyme isotope method, [$^{3}$H]-thymidine incorporation, C3H/HeJ mouse thymocytes proliferation, the addition of 5 $\mu$Ci/ml $^{45}Ca^{2+}$ to P388D$_{1}$ cell suspension and assay to sheep red blood cell, respectively. Cytotoxicity, which was expressed as 50% mortality, was occurred by the addition of GR(10$^{-3}$g/ml). Histamine production in mouse spleen cell culture was significantly increased by 48 hour incubation added 0.25$\mu\textrm{g}$/ml of Con A. Con A-dependent T-lymphocyte proliferation was also enhanced by the addition of 0.25 $\mu\textrm{g}$/ml of Con A. GR depressed histamine contents at 10$^{-9}$~10$^{-4}$g/ml. and Con A (0.25 $\mu\textrm{g}$/ml) dependent T-lymphocyte proliferation at 10$^{-5}$~10$^{-4}$g/ml. IL-1 activity was significantly decreased by 10$^{-8}$~10$^{-4}$g/ml of GR. $Ca^{2+}$ uptake was not changed by GR, but antibody production markedly increased at 10.0~50.0 mg/kg of GR. From the above results, it is suggested that GR have immuno-regulatory action; GR decreased cell-mediated immune response and increased antibody production by B lymphocyte at high doses.