• Clean Technology
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• v.27 no.1
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• pp.69-78
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• 2021

Vegetable oils, such as palm oil and cashew nut shell liquid (CNSL), are used as major raw materials for bio-diesel in transportation and bio-heavy oil in power generation in South Korea. However, due to the high unsaturation degree caused by hydrocarbon double bonds and a high content of oxygen originating from the presence of carboxylic acid, the range of applications as fuel oil is limited. In this study, hydrotreating to saturate unsaturated hydrocarbons and remove oxygen in mixed bio-oil containing 1/1 v/v% palm oil and CNSL on monometallic catalysts (Ni and Cu) and bimetallic catalysts (Ni-Zn, Ni-Fe, Ni-Cu Ni-Co, Ni-Pd, and Ni-Pt) was perform under mild conditions (T = 250 ~ 400 ℃, P = 5 ~ 80 bar and LHSV = 1 h-1). The addition of noble metals and transition metals to Ni showed synergistic effects to improve both hydrogenation (HYD) and hydrodeoxygenation (HDO) activities. The most promising catalyst was Ni-Cu/��-Al2O3, and in the wide range of the Ni/Cu atomic ratio of 9/1~1/4, the conversion for HYD and HDO reactions of the catalysts were 90-93% and 95-99%, respectively. The tendency to exhibit almost constant reaction activity in these catalysts of different Ni/Cu atomic ratios implies a typical structure-insensitive reaction. The refined bio-oil produced by hydrotreating (HDY and HDO) had significantly lower iodine value, acid value, and kinetic viscosity than the raw bio-oil and the higher heating value (HHV) was increased by about 10%.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.325-331
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• 2007

This study was aimed to find out methods for preventing scale formation from the struvite treated water, and improving ammonium nitrogen removal efficiency in the application of struvite crystallization for ammonium fluoride wastewater wastement. During the struvite mystallization seeding effects varied with G.td value applied as mixing conditions in the experiment. The removal efficiency of ammonium nitrogen$(NH_4^+-N)$ and phosphorus$(PO_4^{3-}-P)$ increased over 90% in the condition of low $G{\cdot}t_d$ value. In the experiment with seeding, $G{\cdot}t_d$ value was shown to decease four times lower than the one without seeding. When adding over 2% seeding materials in the total water volume, ammonium nitrogen removal efficiencies gradually increased, of which observation was also revealed in a paired-sample T-test with 95% reliability.

• Korean Journal of Food Science and Technology
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• v.5 no.1
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• pp.42-48
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• 1973

Relative retarding effect of BHA, BHT, PG, ${\alpha}-tocopherol$, ascorbic acid, pyrogallol, and antage 3C on the peroxide value and the free fatty acid value development of two groups of edible soybean oils was studied. The antioxidants were added respectively to the oils at a level of 0.05%, and one group of the oils was irradiated, 4 hours daily, with direct sunlight and the other group was stored in a dak place at $45{\pm}0.5^{\circ}C$. The retarding effect of the antioxidants on the P. V. development was, in general, more pronounced in case of the oils stored in the dark place than in case of the irradiated oils. BHT, PG, and antage 3C exhibited, in both cases, strong retarding effect on the P. V. development of the oils. In both cases, ${\alpha}-tocopherol$ showed some retarding effect, but the effect decreased rapidly as storage time increased. The inhibitory effect of the antioxidants on the free fatty acid value development was much more pronounced in case of the irradiated oils than in case of the oils stored in the dark place. The inhibitory effect of pyrogallol on the free fatty acid value development of the oils was, in both cases, especially strong and lasting.

• Food Science and Preservation
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• v.17 no.5
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• pp.637-643
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• 2010

We investigated the characteristics of breads containing Schizandra chinensis Baillon (SCB) added as whole powder, as a powder prepared from juice, and as a concentrate prepared from a 95% (v/v) ethanolic fruit extract, added to wheat flour at 0.5% (w/w). Addition of any form of SCB lowered the pH and increased the titratable acidity in both doughs and breads compared with control values, and the whole and juice powders were more effective in this respect than was the concentrated ethanolic extract. Dough volume during fermentation was increased by addition of whole powder and concentrated ethanolic extract, but no baking loss was evident upon addition of any form of SCB. Regarding the bread surface, the lightness (L) value was increased by addition of juice powder and concentrated ethanolic extract, but neither the redness(a) and nor the yellowness (b) values showed such increases. Internal color measurements showed increased '-a-' value upon addition of any form of SCB, and increased '-b-' value when concentrated ethanolic extract was used, however, there were no significant changes in L value. Sensory evaluation of taste, flavor, color, and overall acceptability showed that bread prepared using whole powder was more acceptable than were the other forms.

• Microbiology and Biotechnology Letters
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• v.27 no.1
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• pp.54-61
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• 1999

Measurement of inhibition of bioluminescence in Photobacterium phosphoreum has been porposed as a sensitive and rapid procedure to monitor toxic substances. However, at first, $EC_{50}$ which shows degree of toxicity to each toxic substances must be calculated. QSAR (Quantitative Structure Activity Relationship) model can be used to estimate $EC_{50}$ to save time and endeavor. Moderately high correlation coefficients ($r^2{\geq}$ 0.97) were calculated from the linear correlation between $EC_{50}$ and molecular connectivity indices of CAHs (chlorinated aliphatic hydrocarbons)such as $^0X$, $^0X^V$, $^1X$, $^2X$ and $^3X^v_c$ and quadratic correlation between $EC_{50}$ and $^0X$, $^0X^V$, $^2X^V$, $^3X_c$, $^3X^V_c$ and P. It shows that the molecular connection indices in carbon structure is contributed to biological characters with linear relation and that in the other one with quadratic relation. The $EC_{50}$ of chlorophenol derivatives had quadratic relation with the value of octanol/water prtition coefficients ($r^2$=0.99) and linear and quadratic relation with the number of chlorine compound (($r^2{\geq}$0.94). This confirms the already known trend of increasing toxicity with increasing ability of a compound to diffuse through cell membrane and number of chlorine substitution.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6B
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• pp.709-721
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• 2008

This paper is to test the applicability of ModKIMSTORM (Modified KIneMatic Wave STOrm Runoff Model) by applying it to Namgangdam watershed of $2,293km^2$. Model inputs (DEM, land use, soil related information) were prepared in 500 m spatial resolution. Using five typhoon events (Saomi in 2000, Rusa in 2002, Maemi in 2003, Megi in 2004 and Ewiniar in 2006) and two storm events (May of 2003 and July of 2004), the model was calibrated and verified by comparing the simulated streamflow with the observed one at the outlet of the watershed. The Pearson's coefficient of determination $R^2$, Nash and Sutcliffe model efficiency E, the deviation of runoff volumes $D_v$, relative error of the peak runoff rate $EQ_p$, and absolute error of the time to peak runoff $ET_p$ showed the average value of 0.984, 0.981, 3.63%, 0.003, and 0.48 hr for 4 storms calibration and 0.937, 0.895, 8.08%, 0.138, and 0.73 hr for 3 storms verification respectively. Among the model parameters, the stream Manning's roughness coefficient was the most sensitive for peak runoff and the initial soil moisture content was highly sensitive for runoff volume fitting. We could look into the behavior of hyrologic components from the spatial results during the storm periods and get some clue for the watershed management by storms.

• Journal of the Korean Society of Costume
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• v.36
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• pp.109-119
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• 1998

For the purpose of standardization and practicability of natural dyeing, the mordanting and dyeing properties of Caseaslpinia Sappan, L. and Brazilin were studied. Appropriate extraction, dyeing and mordanting condition of Caeaslpinia Sappan, L. were determined, and the effect of mordanting method on dye up-take adn color fastness of dyed fabric was investigated. The most absorbance of Caeaslpinia Sappan, L. solution was 445nm, Brazilin was 448nm. The color of bazilin solution was affected by pH 7~9. The optimum temperature to extract Caesalpinia Sappan, L. was 10$0^{\circ}C$ adn dyeing solution for 1 hour. In case mordants concentration, the most absorbance was 0.3%. In case mordanting test, the best and proper temperature to quantities of absorbed mordants in silk was 8$0^{\circ}C$ and the most quantities of absorbed mordants in silk was mordant treatment by Cu. Effective dyeing time to silk was 60min. Effective mordanting temperature was 8$0^{\circ}C$, and its time was 30min. K/S value of dyeing fabrics was recoginazed by mordanting treat-ment, specially Fe, Sn, Al, Cu. K/S value of pre-mordanting was higher than post-mordanting. After soaping treatment K/S value of pre- and post-mordanting silk was decreased and 0.1%(W/V) quantity of mordant was sufficient for treatment. In the case of Caeaslpinia Sappan, L. fastness was increased by mordanting treatment. Mordants and mordanting treatment method affected the amount of absorption and color change of dyed silk.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.3
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• pp.205-211
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• 2011

On board comparison of pH and total alkalinity measurement in seawater was carried out during the JES expedition on R/V Roger Revelle in the East Sea using 550 real seawater samples from the surface to the bottom. Spectrophotometry and potentiometry without liquid junction were compared for pH measurement. The pH values of two methods are generally in a good agreement. Spectrophotometry with a pipette provides higher value compare with the potentiometry in the deep layer, where pH values are lower. However, spectrophotometry without a pipette shows same values with potentiometry within their precision range. The pipetting procedure may remove of $CO_2$ in the sample, which causes increase of pH. Potentiometric titration methods using a closed-cell and an open-cell were compared for the total alkalinity measurement. Values from open cell method are smaller by about 5~10 ${\mu}mol\;kg^{-1}$ than those from closed cell method. This may be caused by the bubble formed in the closed cell during the experiment. Although any analytical method compared in this study for the pH or TA measurement can be applied, special attentions should be paid for satisfactory results.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.3
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• pp.506-513
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• 1998

This study was designed to compare the smoothness by glazing method with that by polishing method after 48 specimens of Ceramco II block, one of porcelain materials used for PFM, were baked according to the manufacturer's directions. The specimens were roughened with new green stone at 15,000rpm for 30 seconds and sandblasted with $25{\mu}$aluminum oxide for 15 seconds. They were divided into 4 groups at random, and 4 groups were prepared as follows : Group I : specimens were autoglazed and overpolished with polishing system. Group II : specimens were polished with only polishing system. Group III : specimens were glazed after adding glazing liquid, vitachrom 'L'-fluid (vita zahnfabrik co. Germany) to the rough surface Group V : specimens were just autoglazed Using the surface roughness tester, Ra, Rmax. and Rz were estimated 5 times per specimen, and recording process of mean value was repeated 3 times. The results were as follows : 1. The Ra of group I and group II was lower than group III and group IV (p<001). 2. There was lower value of Rz in group I and group II than group III and group IV (p<001). 3. The Rmax of group I (overpolished with polishing system after autoglazing) and group II (polished with only polishing system) was lower than group III (glazed after adding glazing liquid) and group IV (autoglazed) (p<001). 4. There was not a statistically significant difference between group I and II and between group III and IV (p>001). 5. The roughness was increase in order of group I, II, III, IV in SEM

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.04a
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• pp.18-25
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• 2001

A new wood-degrading fungus Trichophyton rubrum LKY-7 secretes a high level of laccase in a glucose-peptone liquid medium. The production of laccase by the fungus was barely induced by 2,5-xylidine. The laccase has been purified to homogeneity through three chromatography steps in an overall yield of 40%. The molecular mass of the purified laccase was about 65 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified laccase had the distinct blue color and had basic spectroscopic features of a typical blue laccase: two absorption maxima at 278 and 610 nm and a shoulder at 338 nm. The N-terminus of the laccase has been sequenced, revealing high homology to laccases from wood-degrading white-rot fungi such as Ceriporiopsis subvermispora. The enzyme had a "low" redox potential (0.5 V vs normal hydrogen electrode), yet it was one of the most active laccases in oxidizing a series of representative substrates/mediators. Compared with other fungal laccases, the laccase has a very low Km value with ABTS [2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid] as a substrate and a very high Km value with violuric acid as a substrate. The laccase has the isoelectric point of 4.0. The laccase had very acidic optimal pH values (pH 3-4) while it was more stable at neutral pH than at acidic pH. The laccase oxidized hydroquinone faster than catechol and pyrogallol. The oxidation of tyrosine by the laccase was not detectable under the reaction conditions. The laccase was strongly inhibited by sodium azide and sodium fluoride. fluoride.