• Nano
• /
• v.13 no.10
• /
• pp.1850124.1-1850124.12
• /
• 2018

$TiO_2$ films were deposited from oxygen/titanium tetraisopropoxide (TTIP) plasmas at low temperature by Helicon-PECVD at floating potential ($V_f$) or substrate self-bias of -50 V. The influence of titanium precursor partial pressure on the morphology, nanostructure and optical properties was investigated. Low titanium partial pressure ([TTIP] < 0.013 Pa) was applied by controlling the TTIP flow rate which is introduced by its own vapor pressure, whereas higher titanium partial pressure was formed through increasing the flow rate by using a carrier gas (CG). Then the precursor partial pressures [TTIP+CG] = 0:027 Pa and 0.093 Pa were obtained. At $V_f$, all the films exhibit a columnar structure, but the degree of inhomogeneity is decreased with the precursor partial pressure. Phase transformation from anatase ([TTIP] < 0.013 Pa) to amorphous ([TTIP+CG] = 0:093 Pa) has been evidenced since the $O^+_2$ ion to neutral flux ratio in the plasma was decreased and more carbon contained in the film. However, in the case of -50 V, the related growth rate for different precursor partial pressures is slightly (~15%) decreased. The columnar morphology at [TTIP] < 0.013 Pa has been changed into a granular structure, but still homogeneous columns are observed for [TTIP+CG] = 0:027 Pa and 0.093 Pa. Rutile phase has been generated at [TTIP] < 0:013 Pa. Ellipsometry measurements were performed on the films deposited at -50 V; results show that the precursor addition from low to high levels leads to a decrease in refractive index.

• Journal of Korean Society of Water and Wastewater
• /
• v.34 no.6
• /
• pp.463-471
• /
• 2020

A 1,000 ㎥/d DAF(dissolved air flotation) pilot plant was installed to evaluate the performance of the floating process using the Nakdong River. Efficiency of various DAF operations under different conditions, such as hydraulic loading rate, coagulant concentration was evaluated in the current research. The operation conditions were evaluated, based on the removal or turbidity, TOC(total organic carbon), THMFP(trihalomethane formation potential), Mn(manganese), and Al(aluminum). Also, particle size analysis of treated water by DAF was performed to examine the characteristics of particles existing in the treated water. The turbidity removal was higher than 90%, and it could be operated at 0.5 NTU or less, which is suitable for the drinking water quality standard. Turbidity, TOC, and THMFP resulted in stable water quality when replacing the coagulant from alum to PAC(poly aluminum chloride). A 100% removal of Chl-a was recorded during the summer period of the DAF operations. Mn removal was not as effective as where the removal did not satisfy the water quality standards for the majority of the operation period. Hydraulic loading of 10 m/h, and coagulant concentrations of 40 mg/L was determined to be the optimal operating conditions for turbidity and TOC removal. When the coagulant concentration increases, the Al concentration of the DAF treated water also increases, so coagulant injection control is required according to the raw water quality. Particle size distribution results indicated that particles larger than 25 ㎛ showed higher removal rates than smaller particles. The total particel count in the treated water was 2,214.7 counts/ml under the operation conditions of 10 m/h of hydraulic loading rate and coagulant concentrations of 60 mg/L.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.7
• /
• pp.45-54
• /
• 2006

Resistivity cone penetrometer test (RCPT) can be employed at a relatively low cost for in-situ delineation of subsurface contamination. While the resistivity measurement has a potential to investigate the subsurface contamination, resistivity measurements alone will lead to some degree of ambiguity in the results. In this study, capacitance measurement was incorporated into the RCPT to overcome the ambiguity inherent in electrical resistivity measurements. This study is focused on verifying the applicability of resistivity and capacitance measurements of CPT module to provide information on subsurface contaminated by heavy metal and petroleum hydrocarbon. Laboratory model tests were performed to evaluate the sensitivity of the measured resistivity and relative capacitance on the water content and different types of contaminants. Test results show that simultaneous measurement of electrical resistivity and capacitance can give more reliable information on subsurface contamination. Electrical measurements of the CPT module showed high applicability to be used in detecting saturated soils contaminated by heavy metal and diesel plume floating above the groundwater table.

• Ocean Systems Engineering
• /
• v.13 no.2
• /
• pp.173-193
• /
• 2023

Reliable prediction of the motion of FOWT (floating offshore wind turbine) and associated mooring line tension is important in both design and operation/monitoring processes. In the present study, a 5MW OC4 semisubmersible wind turbine is numerically modeled, simulated, and analyzed by the open-source numerical tool, OpenFAST and in-house numerical tool, Charm3D-FAST. Another commercial-level program FASTv8-OrcaFlex is also introduced for comparison for selected cases. The three simulation programs solve the same turbine-floater-mooring coupled dynamics in time domain while there exist minor differences in the details of the program. Both the motions and mooring-line tensions are calculated and compared with the DeepCWind 1/50 scale model-testing results. The system identification between the numerical and physical models is checked through the static-offset test and free-decay test. Then the system motions and mooring tensions are systematically compared among the simulated results and measured values. Reasonably good agreements between the simulation and measurement are demonstrated for (i) white-noise random waves, (ii) typical random waves, and (iii) typical random waves with steady wind. Based on the comparison between numerical results and experimental data, the relative importance and role of the differences in the numerical methodologies of those three programs can be observed and interpreted. These comparative-study results may provide a certain confidence level and some insight of potential variability in motion and tension predictions for future FOWT designs and applications.

• The Journal of Internal Korean Medicine
• /
• v.25 no.2
• /
• pp.202-213
• /
• 2004

Object : Objective: This study was conducted to investigate the anti-cancer effects of Mylabris phalerata (반모) in some kinds of cancer cells. Materials and Methods: Some kinds of cancer cells lines were treated. We used nine kinds of cancer cell lines, such as stomach cancer cells (Kato), lung cancer cells (Calu-1, NCI-H 1395), urinary bladder cancer cells (HS789T), bone cancer cells (Saos-2), brain cancer cells (SK-N-MC), liver cancer cells (Hep-G2), skin cancer cells (Mo-1) and prostate cancer cells (PC-3) with the water decoction of Mylabris phalerata. The histological changes of all cell lines in the media (RPMI-1640) containing the decoction of Mylabris phalerata were observed and we examined cell death assay by trypan blue exclusion testing was examined. Finally, the change of mitochondrial membrane potential was measurd and the inhibitory effect of Mylabris phalerata on cell increase was examined by analyzing the cell cycle. Results: In histologic change all cancer cell lines showed withdrawn and floating appearance that is typical in cellular impairment. Most of the cell lines showed over 50% death rate after 24 hours in trypan blue exclusion tests. Especially the stomach, urinary bladder. brain and liver cell lines showed over 30% death rate after 12 hours. All cell lines treated with Mylabris phalerata were less stained than the control group and the mitochondrial membrane potential in the Mylabris phalerata treated cell lines was markedly lower than that in the control group. The measurement of DNA quantity in all cell lines showed the disappearance of the peak and the thickened left axis, which suggests that all cellular DNA degraded. Conclusion: Mylabris phalerata had cytotoxicity on various kinds of cancer cell lines and the mechanism of that was the impairment of mitochondria by the breakdown of the mitochondrial cell membrane. We propose that this is in part attributable to the destruction of DNA in cancer cells.

• Food Science of Animal Resources
• /
• v.37 no.1
• /
• pp.87-97
• /
• 2017

This study aimed at optimizing the manufacturing conditions of a milk beverage supplemented with coffee, and monitoring its physicochemical and sensory properties during storage. Raw milk, skim milk powder, coffee extract, and emulsifiers were used to manufacture the beverage. Two sucrose fatty acid esters, F110 and F160, were identified as suitable emulsifiers. The optimum conditions for the beverage manufacture, which can satisfy two conditions at the same time, determined by response surface methodology (RSM), were 5,000 rpm primary homogenization speed and 0.207% sucrose fatty acid emulsifier addition. The particle size and zeta-potential of the beverage under the optimum condition were 190.1 nm and $-25.94{\pm}0.06mV$, respectively. In comparison study between F110 added group (GF110) and F160 added group (GF160) during storage, all samples maintained its pH around 6.6 to 6.7, and there was no significant difference (p<0.05). In addition, GF110 showed significantly higher zeta-potential than GF160 (p<0.05). The particle size of GF110 and GF160 were approximately 190.1 and 223.1 nm, respectively at initial. However, size distribution of the GF160 tended to increase during storage. Moreover, increase of the particle size in GF160 was observed in microphotographs of it during storage. The $L^*$ values gradually decreased within all groups, whereas the $a^*$ and $b^*$ values did not show significant variations (p<0.05). Compared with GF160, bitterness, floating cream, and rancid flavor were more pronounced in the GF110. Based on the result obtained from the present study, it appears that the sucrose fatty acid ester F110 is more suitable emulsifier when it comes to manufacturing this beverage than the F160, and also contributes to extending product shelf-life.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.45 no.3
• /
• pp.307-317
• /
• 2019

To develop sustainable new natural anti-aging ingredients from Korean native plants, we investigated the cultivation potential of Nymphoides indica using the eco-friendly aquaponics system, and tested the anti-aging effects from N. indica extracts. N. indica could be grown in aquaponics system using floating leaved deep water culture method, and propagated through rhizome propagation. It was confirmed that the nitrate ($80{\mu}g/mL$), potassium ($63.5{\mu}g/mL$) and water temperature ($25^{\circ}C$) greatly affected the cultivation of the N. indica. In addition, synergistic effects were found when two major components (3,7-di-O-methylquercetin-4'-O-${\beta}$-glucoside & sweroside) were present at more than about $5{\mu}g/mL$. The extract had a significant effect on the recovery of skin cells damaged by environmental pollutant such as $benzo[{\alpha}]pyrene$, ammonium nitrate, formaldehyde. It also suppressed $PGE_2$, $TNF-{\alpha}$ and COX-2, and inhibited the production of MMP-1. Taken together, the results suggested that the standardized extracts of N. indica cultivated in the aquaponics has considerable potential as a new cosmetics ingredient with an anti-aging effect.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2002.09a
• /
• pp.139-162
• /
• 2002

Since weak zones or geological lineaments are likely to be eroded, weak zones may develop beneath rivers, and a careful evaluation of ground condition is important to construct structures passing through a river. Dc resistivity surveys, however, have seldomly applied to the investigation of water-covered area, possibly because of difficulties in data aquisition and interpretation. The data aquisition having high quality may be the most important factor, and is more difficult than that in land survey, due to the water layer overlying the underground structure to be imaged. Through the numerical modeling and the analysis of case histories, we studied the method of resistivity survey at the water-covered area, starting from the characteristics of measured data, via data acquisition method, to the interpretation method. We unfolded our discussion according to the installed locations of electrodes, ie., floating them on the water surface, and installing at the water bottom, since the methods of data acquisition and interpretation vary depending on the electrode location. Through this study, we could confirm that the dc resistivity method can provide the fairly reasonable subsurface images. It was also shown that installing electrodes at the water bottom can give the subsurface image with much higher resolution than floating them on the water surface. Since the data acquired at the water-covered area have much lower sensitivity to the underground structure than those at the land, and can be contaminated by the higher noise, such as streaming potential, it would be very important to select the acquisition method and electrode array being able to provide the higher signal-to-noise ratio data as well as the high resolving power. The method installing electrodes at the water bottom is suitable to the detailed survey because of much higher resolving power, whereas the method floating them, especially streamer dc resistivity survey, is to the reconnaissance survey owing of very high speed of field work.

• Korean Journal of Environmental Biology
• /
• v.38 no.1
• /
• pp.1-15
• /
• 2020

This study was conducted to determine whether invasive muskrats settle in the natural ecosystem of Korea. The study also aimed to provide information on the selection of target areas, basic behavioral characteristics, and habitat use-related data, all of which are essential for effective management strategy establishment and site management. To this end, a trend in international muskrat management was identified to examine the management direction according to the settlement stage. We also secured the location of 72 domestic farmers and classified five regions in Gyeonggi-do, Chungcheongnam-do, Gyeongsangbuk-do, and Sejong Special Self-governing City into regions with high potential for natural leakage to raise the need for a quick survey. We determined that muskrats successfully settled in the natural ecosystem of Korea, based on the fact that we consistently identified a muskrat habitat at the same point for three years, from 2016 to 2018, the age of the captured population was estimated to be 1.2 years, and there had been no additional make-up factors near the habitat since 2012. The muskrats that settled in Korea showed a small home range of 0.0027 ㎢ (MCP 95%) and were estimated to show regular mobility before Spring and Autumn. Also, the areas where the muskrat habitat was observed had a high level of habitat environment disturbance and their ecological and food intake characteristics reflected that disturbance. Muskrat traces were high in hydrophyte vegetation, which can be used as a hideout in open waters and where the growth of both floating leaved plants and floating plants are prevalent. Since international invasive muskrats have already settled in the domestic ecosystem and there is concern about their proliferation in the future, the government must consider a preemptive response and scientific management.

• Geophysics and Geophysical Exploration
• /
• v.5 no.4
• /
• pp.223-235
• /
• 2002

Since weak Bones or geological lineaments are likely to be eroded, there may develop weak Bones beneath rivers, and a careful evaluation of ground condition is important to construct structures passing through a river. DC resistivity method, however, has seldomly applied to the investigation of water-covered area, possibly because of difficulties in data aquisition and interpretation. The data aquisition having high quality may be the most important factor, and is more difficult than that in land survey, due to the water layer overlying the underground structure to be imaged. Through the numerical modeling and the analysis of a case history, we studied the method of resistivity survey at the water-covered area, starting from the characteristics of measured data, via data acquisition method, to the interpretation method. We unfolded our discussion according to the installed locations of electrodes, ie., floating them on the water surface, and installing them at the water bottom, because the methods of data acquisition and interpretation vary depending on the electrode location. Through this study, we could confirm that the DC resistivity method can provide fairly reasonable subsurface images. It was also shown that installing electrodes at the water bottom can give the subsurface image with much higher resolution than floating them on the water surface. Since the data acquired at the water-covered area have much lower sensitivity to the underground structure than those at the land, and can be contaminated by the higher noise, such as streaming potential, it would be very important to select the acquisition method and electrode array being able to provide the higher signal-to-noise ratio (S/N ratio) data as well as the high resolving power. Some of the modified electrode arrays can provide the data having reasonably high S/N ratio and need not to install remote electrode(s), and thus, they may be suitable to the resistivity survey at the water-covered area.