• Resources Recycling
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• v.17 no.5
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• pp.3-10
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• 2008

We researched recycle of mixed waste acids including HF, $CH_{3}COOH$, $HNO_3$ produced during semiconductor wafer process. At first, we recovered HF in form of $Na_{2}SiF_6$ by precipitation using $NaNO_3$ and $Na_{2}SiO_3$. Concentration of HF was made down from 110 g/L, initial concectration, to 0.5 g/L and Recovery rate of HF was 99.5%. After recovery of HF, concentration of $HNO_3$ and $CH_{3}COOH$ is 498 g/L, 265 g/L respectively. From that mixed acid, we recovered $CH_{3}COOH$ using 2 stages of fractional distillation. In first stage, $CH_{3}COOH$ was distilled for separation from $HNO_3$. And in second stage, we recoverd refined $CH_{3}COOH$ by using fractional distillation for removing a little amount of $HNO_3$ in $CH_{3}COOH$ vapor. The concentration of recovered $CH_{3}COOH$ in second stage is 20% and finally recovery rate of $CH_{3}COOH$ is about 87.5%.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.147-152
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• 1999

HPLC was used for determining polyphenols which are known as the functional compounds in the unripe apples Fuji and Aori. The changes in their contents caused by heat treatments were monitored. The carbohydrate contents in Fuji and Aori were 14.1% and 13.5% respectively. Both apple juices showed pH 3.2 and $8.0\;brix^{\circ}$, which were relatively low levels. The major polyphenols were composed of (+)-catechin, chlorogenic acid, (-)-epicatechin, and tannic acid. Total polyphenol contents in Fuji and Aori were 0.11, 0.12% by Folin-Denis method. HPLC analysis of polyphenols showed that four major components were contained by 0.06% in Fuji and 0.07% in Aori. Chlorogenic acid was three times higher in Fuji than in Aori. After water blanching, the area percent of polyphenols resulted in an increase by 3.54% in Fuji but a decrease by 2.93% in Aori. Pasteurization of juices led to decrease by 1.39% and 3.31% respectively. Blanching and pasteurization of unripe apple juices induced negligible changes in polyphenol contents during storage. During concentration, polyphenol contents increased in proportion to the concentration of unripe apple juices.

• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1230-1239
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• 2010

Five bacterial species, capable of degrading the recalcitrant organic compounds (ROCs) diethyleneglycol monomethylether (DGMME), 1-amino-2-propanol (APOL), 1-methyl-2-pyrrolidinone (NMP), diethyleneglycol monoethylether (DGMEE), tetraethyleneglycol (TEG), and tetrahydrothiophene 1,1-dioxide (sulfolane), were isolated from an enrichment culture. Cupriavidus sp. catabolized $93.5{\pm}1.7$ mg/l of TEG, $99.3{\pm}1.2$ mg/l of DGMME, $96.1{\pm}1.6$ mg/l of APOL, and $99.5{\pm}0.5$ mg/l of NMP in 3 days. Acineobacter sp. catabolized 100 mg/l of DGMME, $99.9{\pm}0.1$ mg/l of NMP, and 100 mg/l of DGMEE in 3 days. Pseudomonas sp.3 catabolized $95.7{\pm}1.2$ mg/l of APOL and $99.8{\pm}0.3$ mg/l of NMP. Paracoccus sp. catabolized $98.3{\pm}0.6$ mg/l of DGMME and $98.3{\pm}1.0$ mg/l of DGMEE in 3 days. A maximum $43{\pm}2.0$ mg/l of sulfolane was catabolized by Paracoccus sp. in 3 days. When a mixed culture composed of the five bacterial species was applied to real wastewater containing DGMME, APOL, NMP, DGMEE, or TEG, 92~99% of each individual ROC was catabolized within 3 days. However, at least 9 days were required for the complete mineralization of sulfolane. Bacterial community diversity, analyzed on the basis of the TGGE pattern of 16S rDNA extracted from viable cells, was found to be significantly reduced in a conventional bioreactor after 6 days of incubation. However, biodiversity was maintained after 12 days of incubation in an electrochemical bioreactor. In conclusion, the electrochemical reduction reaction enhanced the diversity of the bacterial community and actively catabolized sulfolane.

• Journal of Korean Society of Forest Science
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• v.112 no.3
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• pp.374-381
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• 2023

The travel time of flash floods along mountain streams is mainly governed by reach-average velocity, rather than by the point velocity of the locations of interest. Reach-average velocity is influenced by various factors such as stream geometry, streambed materials, and the hydraulic roughness of streams. In this study, the reach-average velocity in mountain streams was measured for storm periods using rhodamine dye tracing. The point cloud data obtained from a LiDAR survey was used to extract the average hydraulic roughness height, such as R_a, R_max, and R_z. The size distribution of the streambed materials (D₅₀, D₈₄) was also considered in the estimation of the roughness height. The field experiments revealed that the reach-average velocities had a significant relationship with flow discharges (v = 0.5499Q^0.6165 ), with an R² value of 0.77. The root mean square error in the roughness height of the R_a-based estimation (0.45) was lower than those of the other estimations (0.47-1.04). Among the parameters for roughness height estimation, the R_a -based roughness height was the most reliable and suitable for developing the reach-average velocity equation for estimating the travel time of flood waves in mountain streams.

• Bulletin of the Korean Mathematical Society
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• v.36 no.3
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• pp.495-502
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• 1999

The commutative product of the distributions $x^r lnx and $x^{-r-1}$ is evaluated for r=0,1,2,.... The commutative product of the distributions $x^rln(x+i0) and $(x+i0)^{-r-1}$ is also evaluated for r=1,2,.... Further products are deduced.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.373-381
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• 1997

In order to investigate the drift of pesticides sprayed on Chinese cabbage, 7 pesticides chlorpyrifos, EPN, pirimiphos-methyl, phenthoate, tetradifon, dicofol and bifenthrin were applied in two sets of field tests. The pesticide residues were quantified bar multiple-residue analysis, in which the recovery rate was 78${\sim}$92% and standard deviation was ${\pm}0.683{\sim}52%$. It was found that most of the tested pesticides were spread by drift to neighbouring area and brought about the contamination of the unsprayed crops. The extent of drift varied depending upon the pesticide, distance and wind direction. The mean residue levels on unsprayed crops were 0.66% at 3 meter distance, 0.10% at 6 m distance and 0.05% at 9 m distance from the applied area and the maximum level was 1.83% of the residue on sprayed crops.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.4
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• pp.278-288
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• 2010

In this paper, we carried out quality assessment and analysis of stereoscopic 3D Television pictures according to ITU-R contribution and recommendation by rating scales using DSCQS (Double-Stimuli Continuous Quality Scale) method. The evaluation results show that overall quality and sharpness of stereoscopic pictures revealed almost no difference compared to cases of mono pictures as to natural outdoor scenes, graphic images, and indoor scenes (about 3.0 above ~ 4.0), but depth perception and sensation of reality of stereoscopic images exhibit better quality performance over mono images as indicated more than 4.0 out of 5.0 grade. Evaluation results should be considered as human factors such as disparity when shooting and/or editing 3DTV.

• Journal of Korean Society of Archives and Records Management
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• v.16 no.3
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• pp.179-207
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• 2016

This study suggested the necessity of the management of R & D management records produced from government-supported science research institutes (the so-called "gwagichulyeon") and of a record management manual (item). As such, it gathered rules with regard to record management, conducted a survey, and interviewed general R & D managers. As a result of the research, the ratio of the arrangement of R & D managers to R & D management departments is 100%; however, the ratio of the arrangement of record managers is 33.3%-50%, and the ratio of the arrangement of record management departments is 23.1%, which was poor. The enactment ratio of record management rules is 26.4%, and 73.7% of institutes has managed their records under the provision only of document management rules or only of office management rules. R & D management records has been collected according to an institute's capability without a prescribed collection scope, and the conditions with regard to the omission, damage, and loss of records were poor. There are institutes that did not comprehend the production status of R & D management records. Thus, as a response, this study suggested a record management manual (item) established for the arrangement duties of record managers and record management departments as well as for notifications on the status of R & D management records. In addition, this study produced a standardized collection scope and described how to manage R & D management records.

• Bulletin of the Korean Chemical Society
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• v.18 no.2
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• pp.213-217
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• 1997

Magnesium reduction of Mo(N-C6H3-2,6-i-Pr2)2Cl2(DME) in the presence of trimethylphosphine led to a mixture of Mo(N-C6H3-2,6-i-Pr2)(PMe3)2Cl3, 1, and Mo2(PMe3)4Cl4, 2. In solution 1 is slowly air-oxidized to Mo(N-2,6-i-Pr2-C6H3)(OPMe3)(PMe3)Cl3, 3. 1 is chemically inert to carbon nucleophiles (ZnMe2, ZnEt2, AlMe3, AlEt3, LiCp, NaCp, TlCp, NaCp*, MeMgBr, EtMgBr), oxygen nucleophiles (LiOEt, LiO-i-Pr, LiOPh, LiOSPh), and hydrides (LiBEt3H, LiBEt3D). Crystal data for 1: orthorhombic space group P212121, a=11.312(3) Å, b=11.908(3) Å, c=19.381(6) Å, Z=4, R(wR2)=0.0463 (0.1067). Crystal data for 2: monoclinic space group Cc, a=18.384(3) Å, b=9.181(2) Å, c=19.118(3) Å, b=124.98(1)°, Z=4, R(wR2)=0.0228 (0.0568). Crystal data for 3: orthorhombic space group P212121, a=11.464(1) Å, b=14.081(2) Å, c=16.614(3) Å, Z=4, R(wR2)=0.0394 (0.0923).

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.1
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• pp.74-85
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• 2010

In order to formulate the compounded polypropylene(C-PP) which is suitable to an automotive door trim panel, 9 sorts of properties were measured after manufacturing the C-PP using an extruder and an injection machine with polypropylene(PP), ethylene-octene rubber(EOR) and talc. Mixture design, especially extreme vertices design, in DOE with MINITAB - commercial software was used to analyze the data. The relations between each property and each component, for example, $y=0.00907222x_1+0.00870556x_2+0.0155722x_3$ for specific gravity, were found out by the regression analysis and the variance analysis. The optimized formulation of the C-PP for an automotive door trim panel was acquired at PP(77.6962), EOR(11.0238) and talc(10.2800) by use of the response optimizer(mixture) in MINITAB.