• Journal of Energy Engineering
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• v.8 no.2
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• pp.298-308
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• 1999

Experimental study on characteristics of direct contact condensation of steam discharged into a sub-cooled water pool has been performed using five different sizes of horizontal nozzle over a wide range of steam mass fluxes and pool temperatures. Steam condensation phenomena have been observed visually and by taking pictures of steam jets using a high speed video camera. Two different steam jet shapes such as ellipsoidal shape and conical shape were typically observed for a stable steam jet, depending on the steam mass flux and pool temperature. The steam jet expansion ratio and the steam jet length as well as the condensation heat transfer coefficients were determined. The effect of steam mass flux, pool temperature, and nozzle diameter on these parameters were also discussed. Empirical correlations for the steam jet lengths and the condensation heat transfer coefficients as a function of steam mass flux and condensation driving potential were established. The axial and radial temperature distributions in steam jet and in surrounding water were measured. The effect of steam mass flux, pool temperature, and nozzle diameter were also discussed. The condensation regime map, which consists of six regimes such as chugging, transient chugging, condensation oscillation, stable condensation, bubble condensation oscillation, and intermittent oscillation condensation, were established. In addition, the dynamic pressures at the pool wall were measured. The close relation of dynamic pressure and steam condensation mode, which is also dependent on steam mass flux and pool temperature, was found.

• Applied Microscopy
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• v.36 no.2
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• pp.93-99
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• 2006

Gemifloxacin is a synthetic fluoroquinolone antimicrobial agent that exhibits potent activity against most Gram-negative and Gram-positive organisms, and has a comparatively low chondrotoxic potential in immature animals. This study examined the effects of gemifloxacin on the Achilles tendons in immature Sprague-Dawley rats treated by oral intubation once daily for 5 consecutive days from postnatal week 4 onward at doses of 0 (vehicle), and 600mg/kg body weight Ofloxacin was used for comparison. The Achilles tendon sperimens were examined by electron microscopy. In comparison with the vehicle-treated controls, there were ultrastructural changes in all samples from the gemifloxacin- and ofloxacin-treated rats. Degenerative changes were observed in the tenocytes, and the cells that detached from the extracellular matrix were recognizable. The degree of degenerative changes and the number of degenerated cells in the Achilles tendon were significantly higher in the treated group than in the control group. Moreover, among the quinolone treated groups, these findings were more significant in the ofloxacin treated group, and less significant in the gemifloxacin treated group. It is unclear what these findings mean with respect to the possible risk ill juvenile patients treated with gemifloxacin or other quinolones. However, these results show that gemifloxacin causes fewer changes in the connective tissue structures.

• Economic and Environmental Geology
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• v.53 no.5
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• pp.517-528
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• 2020

The objectives of this study were to select optimal soil amendments through analysis of heavy metal availability in soil and uptake to Miscanthus sinensis Anderss. for phytostablization in heavy metal contaminated soil of abandoned metal mine. M. sinensis was cultivated for 6 months at contaminated soil with several soil treatments (bottom ash 1 and 2%, fly ash 1 and 2%, waste lime+oyster 1 and 2%, acid mine drainage sludge (AMDS) 10 and 20%, compost 3.4%, and control). The analysis results of heavy metal concentrations in the soil by Mehlich-3 mehthod, growth and heavy metal concentrations of M. sinensis showed that AMDS 20% was more effective than other amendments for phytostablization, and AMDS 10% showed second effectiveness. Waste lime+oyster, bottom ash and fly ash were also improved compared to control. Mobility of some heavy metal was increased by treatments. Therefore, it is necessary of preparatory investigation of soil condition to select soil amendment to apply on-site phytostablization.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.694-699
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• 2009

The antimutagenic activities of ethanol extracts of Korean and American propolis were tested using Salmonella Typhimurium TA98 with two indirect mutagens of 3-amino-1,4-dimethyl-5H-pyrido [4,3-b]indole (Trp-P-1) and 2-aminoanthracene (2-AA) with S9 mix. Additionally, their antimicrobial activities against acne-related pathogenic strains of Propionibacterium acnes, Staphylococcus Epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa were evaluated using both paper disk method and agar dilution method. Ethanol extracts of Korean and American propolis showed strong inhibitory effects, in a dose dependant manner, against the mutagenicities induced by Trp-P-1 and 2-AA. The antimutagenic effect of ethanol extracts of Korean propolis showed significantly higher protective activity than that of American propolis against the Trp-P-1 induced mutagenicity of S. Typhimurium TA98 at the lower concentration ($1-10\;{\mu}g$), but significantly lower protective activity at the higher concentration ($50-200\;{\mu}g$). The antimutagenic effect of ethanol extract of Korean propolis showed significantly higher protective activity than that of American propolis against the 2-AA induced mutagenicity at the concentration of $1\;{\mu}g$, but significantly lower protective activity than that of the American at the higher concentration ($50-200\;{\mu}g$). Both extracts showed strong antimicrobial activities against all the acne-related pathogens tested, with minimal inhibitory concentration (MIC) values in the range $1,500-5,000\;{\mu}g/mL$.

• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.420-426
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• 2017

Recently, solvent-resistant nanofiltration membranes have been studied for the separation of solvents or solutes using a molecular weight cut-off system of the polymer which is resistant to a specific solvent. Required conditions for these membranes must have are excellent physical properties and solvent resistance. Polybenzimidazole, which is known to be one of the most heat-resistant commercially available polymers, has an excellent inherent solvent resistance and it is even insoluble in stronger organic solvents when cross-linked. Therefore, in this study, the applicability of polybenzimidazole as a solvent resistant nanofiltration membrane was discussed. The membrane was fabricated using the non-solvent induced phase separation method and showed a suitable morphology as a nanofiltration membrane confirmed by field emission scanning electron microscopy. In addition, the permeance of the solvent in the presence or absence of cross-linking was investigated and the stability was also confirmed through long operation. The permeance test was carried out with five different solvents: water, ethanol, benzene, N, N-dimethylacetamide (DMAc) and n-methyl-2-pyrrolidone (NMP); each of the initial flux was $6500L/m^2h$ (water, 2 bar), $720L/m^2h$ (DMAc, 5 bar), $185L/m^2h$ (benzene, 5 bar), $132L/m^2h$ (NMP, 5 bar), $65L/m^2h$ (ethanol, 5 bar) and the pressure between 2 and 5 bar was applied depending on the type of membrane.

• Journal of Broadcast Engineering
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• v.11 no.1 s.30
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• pp.66-79
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• 2006

As constant development of digital broadcasting and data broadcasting system, new technology will be introduced to digital broadcasting and new broadcasting service will be appeared. These services need to be changed and processed to suit each services and the software of the receiver need to be upgraded. Though, generally the digital broadcasting receivers are not getting updated once it's delivered to home for long time and it need to be done by hand or collected each one of them with trouble. Therefore this paper suggests a way to overcome these difficulties via broadcasting stream. This research is to describe how three modules-namely (1) Downloader, downloads new software from data carrousel stream, (2) Update Loader, installs the software received by downloader; and (3) Recoverer, recovers the former version of the software if some serious problem has been occurred during downloading and installing the software. This paper tries to realize the accommodation of terrestrial STB based on the new technique and service following ATSC A-97 agreement.

• Journal of Broadcast Engineering
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• v.9 no.1
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• pp.83-90
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• 2004

DVB-MHP recommends that NPT(normal play time) be used as the times of stream events. NPT is the local time within an event(TV program). But we found that commercial transport stream (TS) generators and middlewares for DVB-MHP settop boxes are not ready to support the use of NPT by applications. In particular, TS generators do not create NPT reference descriptors needed to reconstruct NPT at the TV receiver. This situation is undesirable because program providers cannot experiment with the idea of synchronized applications. So we have implemented a TS generator that inserts NPT reference descriptors to TS and MyGetNPT API to approximately reconstruct NPT. STC (system time clock) is needed to reconstruct NPT, but Xlets are not allowed to read it. So, we approximate STC by using PCR (program clock reference) and the Java system tune. In this method, the stream generator extrats PCRs from an existing TS and inserts them into null TS packets in the form of MPEG sections, which can be read by Xlets. Because PCRs are displaced into new positions in TS, their values should be adjusted based on the time intervals between the original positions and the new positions. We implemented a synchronized application by using our TS generator and MyGetNPT API, where the task of stream events are to display graphic images. We found that graphic images are displayed where 240 ㎳ from their intended time, where 240ms is a human tolerance for the synchronization skew between graphic image and video.

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.805-809
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• 2006

Ozonized olive oil was tested for its mutagenic potential in a Salmonella/microsome assay. Additionally, antimicrobial activity was tested against Propionibacterium acnes, Staphylococcus epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa, pathogenic strains related to acne, using the paper disk and agar dilution method. Ozonized olive oil showed antimicrobial activities against all the strains tested, with minimal inhibitory concentrations (MICs) values in a range of 2${\sim}$10 mg/mL. Mutagenicity of ozonized olive oil was evaluated with Salmonells typhimurium TA98, TA100 and Ta1535, with and without addition of S9 mixture. No increase in the number of $his^{+}$ revertants over the negative control (solvent and non-ozonized olive oil) values was observed with TA98 (1,000 ${\mu}g/plate$), TA100 (1,500 ${\mu}g/plate$) and TA1535 (1,500 ${\mu}g/plate$) strains. The results from this study suggested that ozonized olive oil does not show any mutagenic potential.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.631-636
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• 2018

The problem that the existing the magnetic resonance image (MRI) was prone to have not only long readout duration and low bandwidth in the phase-encode direction, but also geometric distortion was pointed out. The purpose of this study is to identify the usefulness of FOCUS-DWI through comparing FOCUS-DWI with the Conventional-DWI on a degree of uniformity and artifacts caused by the distance change in the central axis within the magnetic field. In terms of artifacts, there happened irregular striped artifacts in the Conventional-DWI technique, which in particular, more often arose in the central axis. Also, the overlap of imaging drastically increased. By contrast, there were no irregular striped artifacts in the FOCUS-DWI technique. In conclusion, it was found that the FOCUS-DWI technique was superior to the Conventional-DWI technique in terms of artifacts, the overlap of imaging, and a degree of uniformity. In addition, there was no difference of the change in distance from the central axis between the FOCUS-DWI technique and the Conventional-DWI technique. Thus, it is considered the FOCUS-DWI technique having less imaging distortion and high image quality will be highly clinically used.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.5 no.2
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• pp.119-127
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• 1995

The purpose of this study was to determine the effects of surface-treatment by zinc salts on break-through and adsorption capacity of toluene. Firstly, the coconut activated carbon treated the surface with zinc salts, were exposed by the spike sample(toluene, 69.02ppm, $260.1mg/m^3$), and then the effects of zinc salts were examined by using the gas adsorption kinetics. The results obtained were as follows : 1) BET(Brumaure Emmett Teller) surface area were $954.4m^3/g$ in coconut activated carbon treated with 0.0001 N $Zn(NO_3)_3$ $6H_2O$, and $830.3m^2/g$ in coconut activated carbon treated with 0.0001 N $ZnCl_2$. 2) Migration was decreased in coconut activated carbon treated with the thin level of zinc salts. 3) Breakthrough volume were 73.07 L in coconut activated carbon treated with 0.0001 N $Zn(NO_3)_3$ $6H_2O$, and 72.76 L in charcoal treated with 0.0001 N $ZnCl_2$. 4) ${\tau}$ values(the time required for 50% breakthrough) were 1046.1 min in coconut activated carbon treated with 0.0001 N $ZnCl_2$ and 921.2 min in coconut activated carbon treated with 0.0001 N $Zn(NO_3)_3$ $6H_2O$. 5) Maximum adsorption capacity was 53.9 mg/tube in coconut activated carbon treated with 0.0001 N $ZnCl_2$ and 47.4 mg/tube in coconut activated carbon treated with 0.0001 N $Zn(NO_3)_3$ $6H_2O$. In conclusion, the coconut activated carbon treated the surface with the thin concentration of zinc salts, decreased the breakthrough and increased the BET surface area and the adsorption capacity in case of sampling airborne toluene.