• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.84-91
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• 2008

Generalized hydrodynamic (GH) theory for multi-species gas and the computational models are developed for the numerical simulation of hypersonic rarefied gas flow on the basis of Eu's GH theory. The rotational non-equilibrium effect of diatomic molecules is taken into account by introducing excess normal stress associated with the bulk viscosity. The numerical model for the diatomic GH theory is developed and tested. Moreover, with the experience of developing the dia-tomic GH computational model, the GH theory is extended to a multi-species gas including 5 species; O$_2$, N$_2$, NO, O, N. The multi-species GH model includes diffusion relation due to the molecular collision and thermal phenomena. Two kinds of GH models are developed for an axisymmetric flow solver. By compar-ing the computed results of diatomic and multi-species GH theories with those of the Navier-Stokes equations and the DSMC results, the accuracy and physical consistency of the GH computational models are examined.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년 추계학술대회논문집
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• pp.84-91
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• 2008

Generalized hydrodynamic (GH) theory for multi-species gas and the computational models are developed for the numerical simulation of hypersonic rarefied gas flow on the basis of Eu's GH theory. The rotational non-equilibrium effect of diatomic molecules is taken into account by introducing excess normal stress associated with the bulk viscosity. The numerical model for the diatomic GH theory is developed and tested. Moreover, with the experience of developing the dia-tomic GH computational model, the GH theory is extended to a multi-species gas including 5 species; $O_2,\;N_2$, NO, O, N. The multi-species GH model includes diffusion relation due to the molecular collision and thermal phenomena. Two kinds of GH models are developed for an axisymmetric flow solver. By compar-ing the computed results of diatomic and multi-species GH theories with those of the Navier-Stokes equations and the DSMC results, the accuracy and physical consistency of the GH computational models are examined.

• Bulletin of the Korean Chemical Society
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• 제28권3호
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• pp.403-407
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• 2007

The anodic degradation of benzoquinone(BQ), a model compound for wastewater treatment was carried out using a home-made flow-through electrochemical cell with carbon fibers. To optimize the controlled current electrolysis condition of an aqueous BQ solution, the experimental variables affecting the degradation of BQ, such as the applying current, pH, reaction time, and flow rate of the BQ solution were examined. The degradation products of the oxidation reaction were identified by High Performance Liquid Chromatography and Inductively Coupled Plasma Atomic Emission Spectrometer. Low molecular weight aliphatic acids, and CO2 were the major products in this experiment. The removal efficiency of BQ from the solution increased with the applying current and time. 99.23% of 1.0 × 10-2 M BQ was degraded to aliphatic acids and CO2 when the applying current is 175 mA in a 12 hr electrolysis.

• 설비공학논문집
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• 제11권6호
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• pp.733-739
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• 1999

A modified low-Re $k-\varepsilon$ model is used for the calculation of drag-reducing turbulent flow by polymer injection in a pipe. With the viscoelastic model, molecular viscosity in the definition of turbulent viscosity is related to elongations viscosity of the solution to account for the effects of drag reduction. Finite volume method is used for the discretization, and power-law scheme is used as a numerical scheme. Computed dimensionless velocity profiles are in good agreements with the experimental data in case of low drag reductions. However, in case of high drag reductions, they deviate largely from the measurements in the central zone of the flow field.

• Bulletin of the Korean Chemical Society
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• 제21권9호
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• pp.875-881
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• 2000

We study the rheological properties of concentrated polymer solution and the melt under simple shear and elon-gational flow using Brownian dynamicssimulation. In order to describe the anisotropic molecular motion, we modifiedthe Giesekus' mobility tensor by incorporating the finitely extensible non-linear elastic (FENE) spring force into dumbbell model. To elucidate the nature of this model, our simulation results are compared with the data of FENE-P ("P"standsfor the Perterin) dumbbell model and experiments. While in steady state both original FENE and FENE-P models exhibit a similar viscosity response,the growthof viscosity becomes dissimilar as the anisotropy decreases and the flowrate increases. The steady state viscosity obtained from the simulation well describes the experiments including the shear-thinning behavior in shear flow and viscosity-thinning behavior in elongational flow. But the growth of viscosity oforiginal FENE dumbbell model cannot describe the experimental results in both flow fields.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.66-69
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• 2001

Effect of $N_2$ flow rate on properties of GaN thin films grown by plasma-enhanced molecular beam epitaxy(PEMBE) was discussed to optimize the quality of thin films. It was found that at low $N_2$ flow rate indicating high III/V flux ratio, the growth rate of GaN thin films was controlled by $N_2$ flux, and at high $N_2$ flow rate the growth rate was not controlled by $N_2$ flux any longer. It was also found that III/V flux ratio affected film quality. The film grown at higher $N_2$ flow rate showed low background carrier concentration, higher carrier mobility, and narrow FWHM in band-edge emission of low temperature PL. It is thought that the film in more Ga flux region was grown by 2-dimensional layer-by-layer growth mode, and the film in more nitrogen region was grown by 3-D island growth mode. All samples exhibited a good crystallinity.

• 식물조직배양학회지
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• 제25권2호
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• pp.81-88
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• 1998

Southeast Asian javanica 벼 품종 Tinawen의 진탕 배양세포로부터 나출된 원형질체의 효과적인 배양과 식물체 재분화가 조사되었다. Lolium multiforum과 Oryza ridleyi의 진탕 배양세포들을 feeder cell로 사용했고 여러가지 재분화 배지를 이용하여 원형질체로부터 유도된 colony들을 재분화 시켰으며, 또한 식물체 재분화율을 높히기 위해 원형질체로 부터 유도된 colony들을 dehydration 시켜 재분화율을 조사하였다. L multiflorum 또는 O. ridleyi의 진탕 배양세포들을 feeder cell로 사용했을 때 원형질체의 평판효율은 feeder cell type과 age에 따라 차이가 났지만 0.09%에서 1.48% 범위로 나타났고, L. multiflorum을 feeder cell로 사용했을 때가 O. ridleyi cell을 사용했을때 보다 6배 높게 원형질체 평판효율을 얻었다. Feeder cell로 L. multiflorum을 사용하여 배양된 원형질채로부터 유도된 colony들을 dehydration 시킨 경우는 19.3-31.7%, O. ridleyi을 사용한 경우는 13.0-18.0%, 또한 이들 두 진탕 배양세포들을 혼합한 것을 사용한 경우는 18.0-22.0%의 식물체 재분화율을 얻은 반면에, dehydration을 시키지 않았을 때는 각각 2.0-7.0%, 3.0-5.0%, 0-4.0%의 재분화율을 얻었다. 원형 질체에서 재분화된 식물체의 flow cytometry를 이용한 배수성 분석 결과 대부분의 식물체가 이배체로 나타난 반면, 단지 34개중 두 식물체에서만이 4배체로 나타났다. 재분화된 식물체들은 온실에 옮겨 기른 결과 정상적인 임성을 나타내었다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권9호
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• pp.5317-5323
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• 2013

Breast cancer is the most prevalent cancer and one of the leading causes of death among women in the world. Plants and herbs may play an important role in complementary or alternative treatment. The aim of this study was to evaluate the antioxidant and anti-proliferative potential of Urtica dioica. The anti oxidant activity of an aqueous extract of Urtica dioica leaf was measured by MTT assay and the FRAP method while its anti-proliferative activity on the human breast cancer cell line (MCF-7) and fibroblasts isolated from foreskin tissue was evaluated using MTT assay. Mechanisms leading to apoptosis were also investigated at the molecular level by measuring the amount of anti and pro-apoptotic proteins and at the cellular level by studying DNA fragmentation and annexin V staining by flow cytometry. The aqueous extract of Urtica dioica showed antioxidant effects with a correlation coefficient of $r^2$=0.997. Dose-dependent and anti-proliferative effects of the extract were observed only on MCF-7 cells after 72 hrs with an $IC_{50}$ value of 2 mg/ml. This anti proliferative activity was associated with an increase of apoptosis as demonstrated by DNA fragmentation, the appearance of apoptotic cells in flow cytometry analysis and an increase of the amount of calpain 1, calpastatin, caspase 3, caspase 9, Bax and Bcl-2, all proteins involved in the apoptotic pathway. This is the first time such in vitro antiproliferative effect of aqueous extract of Urtica dioica leaf has been described for a breast cancer cell line. Our findings warrant further research on Urtica dioica as a potential chemotherapeutic agent for breast cancer.

• Asian Pacific Journal of Cancer Prevention
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• 제15권2호
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• pp.769-773
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• 2014

Fangchinoline (Fan) inhibits cell proliferation and induces apoptosis in several cancer cell lines. The effects of Fan on cell growth and proliferation in breast cancer cells remain to be elucidated. Here, we show that Fan inhibited cell proliferation in the MDA-MB-231 breast cancer cell line through suppression of the AKT/Gsk-3beta/cyclin D1 signaling pathway. Furthermore, Fan induced apoptosis by increasing the expression of Bax (relative to Bcl-2), active caspase 3 and cytochrome-c. Fan significantly inhibited cell proliferation of MDA-MB-231 cells in a concentration and time dependent manner as determined by MTT assay. Flow cytometry analysis demonstrated that Fan treatment of MDA-MB-231 cells resulted in cell cycle arrest at the G1 phase, which correlated with apparent downregulation of both mRNA and protein levels of both PCNA and cyclin D1. Further analysis demonstrated that Fan decreased the phosphorylation of AKT and GSK-3beta. In addition, Fan up-regulated active caspase3, cytochrome-c protein levels and the ratio of Bax/Bcl-2, accompanied by apoptosis. Taken together, these results suggest that Fan is a potential natural product for the treatment of breast cancer.

• Bulletin of the Korean Chemical Society
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• 제33권3호
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• pp.825-827
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• 2012

In this study, the variation in surface morphology of copper phthalocyanine (CuPc) thin films treated with a flow of acetone vapor assisted by nitrogen carrier gas was investigated. The CuPc nanorods with similar dimensions were well dispersed throughout the whole film surfaces after ~20 min. of treatment. However, the electronic absorption spectra only changed slightly, which indicates that molecular stacking was not altered during treatment. This treating method is simple and more advantageous compared to other solvent treating technologies such as mixed solvent spray treatment using organic solvents and water since it requires relatively mild treating conditions and does not need the presence of water.