• Fire Science and Engineering
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• v.33 no.3
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• pp.1-8
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• 2019

The international standard for FT-IR gas analysis of fire effluents in ISO 5660-1 cone calorimeter has been being developed in ISO TC 92. A comparison of the round-robin test of WD 21397 was conducted with six participating laboratories in 2018. The test specimens were PMMA, rigid PU foam board, and PVC flooring. The measurement quantities were the time-to-ignition, peak heat release rate, total heat release, and effective heat of combustion for a cone calorimeter test and peak gas concentration, gas generation, and gas yield for FT-IR gas analysis. No outliers were identified. For the cone calorimeter quantities, the repeatability and reproducibility were 1.5% and 9.8%, respectively. For FT-IR gas analysis, the repeatability and reproducibility was 12.9% and 27.9%, respectively.

• Membrane Journal
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• v.18 no.1
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• pp.26-34
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• 2008

In this study, periodic water-back-flushing using permeate water was performed to minimize membrane fouling and to enhance permeate flux in advanced water treatment system by ceramic microfiltration. We investigated effect of water-back-flushing period (FT) and time (BT), and tried to find the optimal operating conditions. BT was fixed at 3 sec and FT was changed in $30{\sim}120$ sec to inspect effect of FT. Also, FT was fixed at 120 sec and BT was changed as $3{\sim}12$ sec at experiment of BT effect. At both two experiments, TMP was fixed at 1.52 bar, water-back-flushing pressure at 0.98 bar, feed flow rate at 0.5 L/min, and feed water temperature at $20^{\circ}C$. As the result, optimal FT was 30 sec at fixed BT 3 sec in our experimental range. It means that the more frequent back-flushing was the more effective to reduce membrane fouling. However, there were not large effects of FT due to a short BT. Then, increasing BT at fixed FT 120 sec could decrease resistance of membrane fouling ($R_f$) and increase permeate flux (J) and dimensionless permeate flux ($J/J_o$), and the most total permeate volume ($V_T$) could be produced at the maximum BT 12 sec.

• Journal of Korean society of Dental Hygiene
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• v.4 no.2
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• pp.165-177
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• 2004

The purpose of this study was to analyze the influence of child's general property, mother's social and economic property, mother's knowledge and behavior in oral hygiene upon the appearance and treatment of child's primary tooth decay. For the purpose, oral examination was applied to one hundred three(103) small children who were at the age between four(4) and seven(7) and went to two(2) places of day care centers located in Seoul, and questionnaire was done to their mothers. The results of the study are as follows. 1. The number of children's dt is 1.55, the number of their ft is 1.42, dft index for primary tooth is 2,98, ft rate is 45.61%, and the higher child's age is, the higher their value is. 2. Mother's age, educational background, and occupation does not show significant difference with dft index for primary tooth. The higher mother's monthly average income is, the higher child's ft rate is. 3. dft index for primary tooth does not show significant difference according 10 mother's knowledge in oral hygiene. And, the child of mother using dental floss does show higher it rate in comparison with the one of mother who does not use dental floss, 4. Experience using dental clinic to treatment tooth decay does show significant difference with dft index for primary tooth. And experience using dental clinic for the purpose of oral examination and preventive treatment does show significant difference with ft rate. 5. From the result of multiple regression with dependent variable of dft index for primary tooth, there is no variable having significant influence. From the result of multiple regression with dependent variable of ft rate, explanatory variable is 43%, child's age, mother's occupation, mother's monthly average income, and experience using dental clinic to prevent tooth decay are significant explanatory elements. Through the above results, we can know that mother should practice positive behavior in oral hygiene for child to improve oral health. Under the reason, oral health education should be applied toward mothers as soon as possible, and governmental support should be followed so that mothers can participate in the education.

• Journal of Life Science
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• v.31 no.2
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• pp.175-182
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• 2021

Saccharomyces lysate has the well-known function of soothing the skin in various ways: it is an anti-irritant and can treat skin care conditions, such as skin whitening and antioxidative activity. However, data on the safety for use of Saccharomyces lysate in cosmetics and skin care products are still limited. To design a new cosmetic material with antioxidant and skin-whitening effects, 80 yeast strains were isolated from berries grown in Sunchang. Among the isolates, the FT4-4 strain, which exhibited superior biological activities, was selected for further experiments. The FT4-4 strain was identified as Saccharomyces cerevisiae by 18S rRNA gene sequencing analysis. S. cerevisiae FT4-4 showed higher DPPH radical-scavenging (51.41%), superoxide dismutase (62.23%), and tyrosinase inhibition (64.75%) activities. The highest yield of biomass (3.16 g/l) and maximum growth rate of S. cerevisiae FT4-4 were observed within 16 h. Furthermore, the cytotoxicity potential of S. cerevisiae FT4-4 on B16F10 melanoma cells was measured by an MTT assay, and the results indicated that S. cerevisiae FT4-4 had a capacity to inhibit melanin up to 72.02% at an initial 10 mg/ml concentration. These results suggest that S. cerevisiae FT4-4 could be a promising candidate as a multi-functional material for application in the cosmetic industry, especially because of its antioxidant and skin-whitening effects.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.1
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• pp.27-32
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• 2004

The diamond-like carbon (DLC) films were deposited on the Si (100) wafer by a rf-PECVD method as a function of the mixture rate of methane-hydrogen gas and bias voltage. The bonding structure and mechanical properties of these deposited DLC films were investigated using FT-IR, Raman, and nano-indenter. The deposition rates of DLC films increased with increased flow rate of methane in the gas mixtures and increased bias voltage. The $sp^3/sp^2$ bonding ratio of carbon in thin film and the hardness increased with increasing flow rate of hydrogen in the gas mixtures and increasing bias voltage.

• Applied Science and Convergence Technology
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• v.23 no.1
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• pp.44-47
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• 2014

In this study, we investigated the basic properties of N-doped ethylcyclohexene plasma polymer thin films that deposited by radio frequency (13.56 MHz) plasma-enhanced chemical vapor deposition (PECVD) method with controlled ammonia flow rate. Ethylcyclohexene was used as organic precursor with hydrogen gas as the precursor bubbler gas. Additionally, ammonia ($NH_3$) gas was used as nitrogen dopant. The as-grown polymerized thin films were analyzed using ellipsometry, Fourier-transform infrared [FT-IR] spectroscopy, UV-Visible spectroscopy, and water contact angle measurement. We found that with increasing plasma power, film thickness is gradually increased while optical transmittance is drastically decreased. However, under the same plasma condition, water contact angle is decreased with increasing $NH_3$ flow rate. The FT-IR spectra showed that the N-doped ethylcyclohexene plasma polymer films were completely fragmented and polymerized from ethylcyclohexane.

• Textile Coloration and Finishing
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• v.10 no.3
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• pp.50-56
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• 1998

Nonwoven fabric was treated with chitosan solution to impart antimicrobial activities by pad-dry method. Antimicrobial activity was measured by Shake Flask Method. Two chitosans of different molecular weight(Mw) with similar degree of deacetylation(DDA) were used : ca. 1,800(chitosan oligomer : DDA 84%) and 180,000(DDA 86%). Chitosan oligomer displayed high antimicrobial activity against P. vulgaris at 0.01%, S. aureus and E. coli at 0.05% treatment concentration, shelving above 90% of reduction rate. Chitosan of Mw 180,000 was effective against S. aureus, E. coil and P. vulgaris at 0.05% treatment concentration, showing almost 100% reduction rate. While chitosan of Mw 180,000 shelved reduction rate above 75% against K. pneumoniae and P. aeruginosa at 0.5% treatment concentration, chitosan oligomer was not effective against them. Fabrics become stiffer and less air permeable as treatment concentration increases. Liquid strike-through time of the sample treated with 0.5% chitosan oligomer solution (3.0 sec) was comparable with a hydrophilic finished sample commercially available(2.6 sec).

• Elastomers and Composites
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• v.52 no.4
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• pp.266-271
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• 2017

This study describes the influence of the amount of curing agent and curing temperature on the kinetics of polyurethane elastomers. The urethane prepolymer series was prepared by reacting toluene diisocyanate with polytetramethylene ether glycol at $80^{\circ}C$ for 1 h, and 4,4'-methylene bis(2-chloroaniline) was used as the curing agent. The ratio of the amine group of the curing agent to the isocyanate group of the urethane prepolymer was controlled from 0.85 to 1.05 at curing temperatures ranging from 80 to $120^{\circ}C$. The curing rate of the urethane prepolymer was monitored by observing the change in heat flow during the curing process using differential scanning calorimetry (DSC). As either the content of curing agent or the curing temperature was higher, the conversion rate to the polyurethane elastomer was high. The DSC results were compared with those obtained from using real-time FT-IR.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.381.1-381.1
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• 2014

In this study, we investigated the deposition behavior and the etch resistivity of plasma polymerized carbon hardmask (ppCHM) film with the variation of process temperature. The etch resistivity of deposited ppCHM film was analyzed by thickness measurement before and after direct contact reactive ion etching process. The physical and chemical properties of films were characterized on the Fourier transform infrared (FT-IR) spectroscope, Raman spectroscope, stress gauge, and ellipsometry. The deposition behavior of ppCHM process with the variation of temperature was correlated refractive index (n), extinction coefficient (k), intrinsic stress (MPa), and deposition rate (A/s) with the hydrocarbon concentration, graphite (G) and disordered (D) peak by analyzing the Raman and FT-IR spectrum. From this experiment we knew an optimal deposition condition for structure of carbon hardmask with the higher etch selectivity to oxide. It was shown the density of ppCHM film had 1.6~1.9 g/cm3 and its refractive index was 1.8~1.9 at process temperature, $300{\sim}600^{\circ}C$. The etch selectivity of ppCHM film was shown about 1:4~1:8 to undoped siliconoxide (USG) film (etch rate, 1300 A/min).

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.768-776
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• 2015

This study was performed to understand combustion properties four major Indonesian wood species such as Albizia, Gmelina, Mangium and Mindi were investigated by cone-calorimeter for better utilization of theses wood species. Heat release rate (HRR), total heat release (TSR), specific mass loss rate (SMLR), effective heat of combustion (EHC), time to ignition (TTI), flame time (FT), specific extinction area (SEA), smoke production rate (SPR) and CO compound production rate were measured. HRR, THR and FT were proportional to the density of woods. Albizia showed the highest HRR, while Mindi had the lowest HRR. For SPR, Albizia showed the highest value due to its higher SEA. On the other hand, Mindi had the lowest SPR due to a lower SEA value. The highest smoke emission was for Albizia at the beginning of combustion. After 300 seconds, smoke emission of Gmleina and Mangium was increased greatly. Mangium and Mindi showed the highest total carbon dioxide emission. Expecially, Gmelina released the highest carbon monoxide during the combustion period and presented three times higher $CO/CO_2$ ratio than those of other species due to incomplete combustion.