• Journal of the Korean Geographical Society
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• v.16
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• pp.1-9
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• 1977

• Journal of the Korean Geographical Society
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• v.28 no.2
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• pp.112-122
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• 1993

Since more than 50${\%}$ of annual precipitation in Korea falls during Changma, the rainy season of early summer, and Late Changma, the rainy season of late summer, forcasting the onset days Changmas, and the amount related rainfalls would be necessary not only for agriculture but also for flood-control. In this study the authors attempted to build a prediction model for the forecast of the onset date of Changmas. The onset data of each Changma was derived out of daily rainfall data of 47 stations for 30 years(1961~1990) and weather maps over East Asia. Each station represent any of the 47 districts of local forecast under the Korea Meteorological Administration. The average onset dates of Changma during the period was from 21 through 26 June. The dates show a tendency to be delayed in El Ni${\~{n}}o years while they come earlier than the average in La Nina years. In 1982, the year of El Ni${\~{n}}o, the date was 9 Julu, two weeks late compared with the average. The relation of sea surface temperature(SST) over Pacific and Northern hemispheric 500mb height to the Changma onset dates was analyzed for the prediction model by polynomial regression. The onset date of Changma over Korea was correlated with SST in May(SST${_(5)}{^\circ}$C) of the district (8${^\circ}$~12${^\circ}S, 136${^\circ}~148${^\circ}W)of equatirial middle Pacific and the 500mb height in March (MB${_(3)}$"\;"m)over the district of the notrhern Hudson Bay. The relation between this two elements can be expressed by the regression: Onset=5.888SST${_5}"\;"+"\;"0.047MB${_(3)}$"\;"-251.241. This equation explains 77${\%}$ of variances at the 0.01${\%}$ singificance level. The onset dates of Late Changma come in accordance with the degeneration of the Subtro-pical High over northern Pacific. They were 18 August in average for the period showing positive correlation(r=0.71) with SST in May(SST)${_(i5)}{^\circ}$C) over district of IndiaN Ocean near west coast of Australia (24${^\circ}$~32${^\circ}$S, 104${^\circ}$~112${^\circ}$E), but negativ e with SST in May(SST${_(p5)}{^\circ}$ over district (12${^\circ}$~20${^\circ}$S,"\;"136${^\circ}$~148${^\circ}$W)of equatorial mid Pacific (r=-0.70) and with the 500mb height over district of northwestern Siberia (r=-0.62). The prediction model for Late Changma can be expressed by the regression: Onset=706.314-0.080 MB-3.972SST${_(p5)}+3.896 SST${_(i5)}, which explains 64${\%}$ of variances at the 0.01${\%}$ singificance level.

• International Journal of Quality Innovation
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• v.1 no.1
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• pp.106-120
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• 2000

The purpose of this research is to understand the effects of Quality Management Award on stock prices movement and to examine the comparative advantages of quality award system in Korea and the U.S. This study compares the performances of QM Award companies in the stock market with those of the market index in both countries. We develop Korean Quality Award Index(KQA Index) based on the Baldrige Index of NIST in the U.S. We inspect three studies. Study 1 tests if the performances of MB Award winners and S&P500 index have a difference in the stock market. Study 2 tests if the performances of KQA winners and KOSPI(Korean Composite Stock Price Index) have a difference in the stock market. Study 3 tests if the performances of KQA winners and MB Award winners have a difference in the stock market. From the empirical tests, the performances of KQA winners are superior to those of KOSPI and the performances of MB Award winners are superior to those of S&P500 and the performances of MB Award winners are superior to those of KQA winners.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.160-160
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• 2011

In the present work, $TiO_2$ fiilms supported by porous silica gel with high surface area synthesized by atomic layer deposition(ALD). Porous structure of silica substrate could be maintained even after deposit large amount of $TiO_2$ (500 cycles of ALD process), suggesting the differential growth mode of $TiO_2$ on top surface and inside the pore. All the $TiO_2$-covered silica samples showed improved MB adsorption abilities, comparing to bare one. In addition, when silica surface was covered with $TiO_2$ films, MB adsorption capacity was almost fully recovered by re-annealing process (500$^{\circ}C$, for 1 hr, in ambient pressure), whereas MB adsorption capacity of bare silica was decreased after re-heaing process. FT-IR study demonstrated that $TiO_2$ film could prevent deposition of surface-bound intermediate species during thermal decomposition of adsorbed MB molecules. Photocatalytic activity of $TiO_2$/silica sample was also investigated.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.397-409
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• 2014

Algal problem in drinking water treatment is being gradually increased by causing deterioration of water supplies therefore, especially taste and odor compounds such as geosmin and 2-MIB occur mainly aesthetic problem by its unpleasant effects resulting in the subsequent onset of complaints from drinking water consumer. Recently, geosmin and 2-MIB are detected frequently at abnormally high concentration level. However, conventional water treatment without advanced water treatment processes such as adsorption and oxidation process, cannot remove these two compounds efficiently. Moreover, it is known that the advanced treatment processes i.e. adsorption and oxidation have also several limits to the removal of geosmin and 2-MIB. Therefore, the purpose of this study was not only to evaluate full scale nanofiltration membrane system with $300m^3/day$ of permeate capacity and 90% of recovery on the removal of geosmin and 2-MIB in spiked natural raw water sources at high feed concentration with a range of approximately 500 to 2,500 ng/L, but also to observe rejection property of the compounds within multi stage NF membrane system. Rejection rate of geosmin and 2-MIB by NF membrane process was 96% that is 4% of passage regardless of the feed water concentration which indicates NF membrane system with an operational values suggested in this research can be employed in drinking water treatment plant to control geosmin and 2-MIB of high concentration. But, according to results of regression analysis in this study it is recommended that feed water concentration of geosmin and 2-MIB would not exceed 220 and 300 ng/L respectively which is not to be perceived in drinking tap water. Also it suggests that the removal rate might be depended on an operating conditions such as feed water characteristics and membrane flux. When each stage of NF membrane system was evaluated relatively higher removal rate was observed at the conditions that is lower flux, higher DOC and TDS, i.e., $2^{nd}$ stage NF membrane systems, possibly due to an interaction mechanisms between compounds and cake layer on the membrane surfaces.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.17-20
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• 1999

The retention and fatigue properties of ferroelectric LiNbO$_3$ thin films were studied. Metal-ferroelectric-semiconductor(MFS) devices by using rapid thermal annealed LiNbO$_3$/Si structures were successfully fabricated and demonstrated nonvolatile memory operations of the MFS devices. The I$_{D}$-V$_{G}$ characteristics of MFSFET\`s showed a hysteresis loop due to the ferroelectric nature of the LiNbO$_3$ thin film. The ferroelectric capacitors showed practically no polarization degradation up to about 10$^{10}$ switching cycles when subjected to symmetric bipolar voltage pulse (peak-to-peak 6V, 50% duty cycle) in the 500kHz. The retention properties of the LiNbO$_3$ thin films were quite good up to about 10$^{3}$ s . s .

• Natural Product Sciences
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• v.23 no.1
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• pp.35-39
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• 2017

D-chiro-inositol (DCI) is a secondary messenger in insulin signal transduction. It is produced in vivo from myo-inositol via action of epimerase. In this study, we evaluated antitumor activity of DCI against human breast cancer both in vitro and in vivo. In order to determine the inhibitory effects of DCI on growth of human breast cancer cells (MDA-MB-231), two different assessment methods were implemented: MTT assay and mouse xenograft assay. MTT assay demonstrated downturn in cell proliferation by DCI treatment (1, 5, 10, 20 and 40 mM) groups by 18.3% (p < 0.05), 17.2% (p < 0.05), 17.5% (p < 0.05), 18.4% (p < 0.05), and 24.9% (p < 0.01), respectively. Also, inhibition of tumor growth was investigated in mouse xenograft model. DCI was administered orally at the dose of 500 mg/kg and 1000 mg/kg body weight to treat nude mouse for 45 consecutive days. On the 45th day, tumor growth of DCI (500 mg/kg and 1000 mg/kg) groups was suppressed by 22.1% and 67.6% as mean tumor volumes were $9313.8{\pm}474.1mm^3$ and $3879.1{\pm}1044.1mm^3$, respectively. Furthermore, breast cancer stem cell (CSC) phenotype ($CD44^+/C24^-$) was measured using flow cytometry. On the 46th day, CSC ratios of DCI (500 mg/kg) and co-treatment with doxorubicin (4 mg/kg) and DCI (500 mg/kg) group decreased by 24.7% and 53.9% (p < 0.01), respectively. Finally, from tumor recurrence assay, delay of 5 days in the co-treatment group compared to doxorubicin (4 mg/kg) alone group was observed. Based on these findings, we propose that DCI holds potential as an anti-cancer drug for treatment of breast cancer.

• Nutrition Research and Practice
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• v.10 no.2
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• pp.139-147
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• 2016

BACKGROUND/OBJECFTIVES: The present study was conducted to examine the inhibitory effect of loquat leaves on MDA-MB-231 cell proliferation and invasion. MATERIALS/METHODS: Female athymic nude mice were given a subcutaneous (s.c.) inoculation of MDA-MB-231 cells and randomly grouped to receive a s.c. injection of either 500 mg/kg ethanol, water extract or vehicle five times a week. Tumor growth, mitotic rate and necrosis were examined. MDA-MB-231 cells were cultured with DMSO or with various concentrations of loquat water or ethanol extract. Proliferation, adhesion, migration, invasion and matrix metalloproteinase (MMP) activity were examined. RESULTS: Tumor growth of xenograft nude mouse was significantly reduced by loquat extracts. The results of mitotic examination revealed that loquat extracts reduced tumor cell division. Both ethanol and water extracts significantly inhibited MDA-MB-231 cell proliferation. The protein expression of ErbB3 was significantly down-regulated by loquat leaf extracts. Loquat leaf extracts increased apoptosis of MDA-MB-231 cells following 24 hour incubation and the ethanol extract was more potent in inducing apoptosis than the water extract. Furthermore, loquat extracts inhibited adhesion, migration and invasion of MDA-MB-231 cells. MMP activity was significantly inhibited by loquat extracts. CONCLUSION: Our results show that extracts of loquat inhibit the growth of tumor in MDA-MB-231 xenograft nude mice and the invasion of human breast cancer cells, indicating the inhibition of tumor cell proliferation and invasion.

• The Journal of Korean Obstetrics and Gynecology
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• v.28 no.2
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• pp.15-25
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• 2015

Objectives : In this study, we investigated the anti-proliferative and apoptosis inducing effect of water extract of Chelidonium majus (CM) on human breast cancer cell MDA-MB-231. Methods : The MTT assay was used to assess cell proliferation. The expression of apoptosis related gene was assessed by quantitative Real-time PCR. Cell apoptosis detected by flow cytometry using Annexin-V/PI staining. Results : Our data revealed that CM inhibited the cell growth in a dose dependent manner (0, 62.5, 125, 250, 500 μg/ml). CM increased mRNA expression of pro-apoptotic genes Bax, caspase-3, and caspase-9. Annexin-V/PI staining assays revealed that apoptosis-induced cell death increased in a dose-dependent manner in cells. Conclusions : CM induces cell death in MDA-MB-231 human breast cancer cell and shows potentials for use in cancer therapy as apoptosis-inducing agent.

• Journal of Ceramic Processing Research
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• v.20 no.2
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• pp.182-186
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• 2019

0.7 mol% Er-TiO2 nanotubes were prepared using a sol-gel derived electrospinning and subsequent calcination at intervals of 50 ℃ from 500 ℃ to 650 ℃ to investigate the effect of calcination temperature on the crystal structure and the photocatalytic activity of methylene blue (MB). X-ray diffraction (XRD) results indicated that Er-TiO2 nanotubes calcined at 500 ℃ were composed of anatase only. However, mixed phases of anatase (51%, 55%, 96%) and rutile (49%, 45%, 4%) were observed for the nanotubes calcined at 550 ℃, 600 ℃ and 650 ℃, respectively. As the calcination temperature rose from 500 ℃ to 600 ℃, the Barrette-Emmett-Teller (BET) surface area and degradation kinetic constant increased from 97.77 ㎡/g to 117.62 ㎡/g and from 1.2 × 10-2min-1 to 1.6 × 10-2 min-1, respectively. The Er-TiO2 nanotubes calcined at 600 ℃ exhibited enhanced MB degradation (87%) compared to that of Er-TiO2 nanofibers (37%) due to the synergic combinations of tailored mixed crystals and larger BET area.