• Journal of the Korean Chemical Society
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• v.58 no.6
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• pp.535-542
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• 2014

A simple and efficient preconcentration method was developed using three-phase liquid phase microextraction prior to HPLC-UV for simultaneous extraction and determination of tetracycline antibiotics (tetracycline, oxytetracycline, and chlortetracycline). The tetracycline antibiotics were separated simultaneously on a column ($C_8$, $3.0{\times}150mm$, $3{\mu}m$) with high selectivity and sensitivity using gradient elution. Under optimized conditions (extraction solvent, heptanal; pH of donor, 9.0; pH of acceptor, 1.0; stirring speed, 700 rpm; NaCl salt, 0%; and extraction time, 60 min), enrichment factors (EF) were between 5.6 and 22.3. The limit of detection (LOD) and limit of quantitation (LOQ) in the spiked urine matrix were in the concentration range of $0.08{\sim}0.8{\mu}g/mL$ and $0.4{\sim}1.6{\mu}g/mL$, respectively. The calibration curves were linear within the range of $0.1{\sim}32{\mu}g/mL$ with the square of the correlation coefficient being more than 0.995. The precision (as a relative standard deviation, RSD) and accuracy (as a relative recovery) within working range were 1.3~9.1% and 84~118%, respectively.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.3
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• pp.27-35
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• 2013

Cotton linter pre-treatment methods using electron beam and sulfuric acid were investigated to prepare high quality regenerated fibers for fabrics. So far, NaOH was used to reduce the degree of polymerization (DP) of the cotton linter for ease of dissolving by cellulose solvent. Two pre-treatment methods were developed to reduce the consumption of the chemicals (NaOH) and to control the DP of cellulose more precisely. Changes in ${\alpha}$-cellulose contents and brightness by the pre-treatments were also important concerns. Both electron beam irradiation and sulfuric acid were shown to be effective on controlling the DP of cellulose and to reduce the chemical consumption, but reduced ${\alpha}$-cellulose contents as well in this study. Sulfuric acid pre-treatment, which needed additional washing process after the pre-treatment when comparing to the electron beam irradiation method, gave the highest brightness and the highest reduction of ${\alpha}$-cellulose content.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.484-489
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• 1994

Solubilization of plant ceil wall(tofu-residue) using enzyme complex obtained by Aspergillus niger CF-34 was attempted. The hydrolysis reaction was done at pH 4.0, $50^{\circ}C$, which were optimum pH and temperature of the enzyme, respectively. At the enzyme dosage of 2.5% (in terms of solid content of tofu-residue) and reaction time of 3 hr, the solubilizing percent of protein and carbohydrate were 62% and 50% respectively. Homogenization prior to enzyme reaction did not have much effect on tofu-residue solubilization. To improve solubility of tofu-residue, additional treatment such as alkali with 0.1% NaOH solution was found to be useful. The results showed that tofu-residue, which mainly consists of cell wall component of cellulose and hemicellulose, was not accessible to enzyme reaction and some prior treatment is required to enhance enzyme hydrolysis.

• Clean Technology
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• v.11 no.2
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• pp.57-67
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• 2005

Epoxy resins are produced by the dehydro condensated reaction with ECH (Epichlorohydrin) and BPA(Bisphenol-A) as raw reactants under sodium hydroxide(NaOH) as a catalyst, and from this reaction, salted water named of brine, which contains ECH derivatives in condition of emulsion as likely as glycidol and polymer resins, is produced as an undesired side product. This brine water is alkaline wastewater and causes process fouling problems by plugging and chemically depositing polymer particles on the surface of inner wall of reactors and pipes, and decreases the biodegradable efficiency in the wastewater process. In this study, the optimization of coagulation and sediment reactions, using inorganic and organic polymer coagulants, were performed to remove the causes occurring the process fouling phenomena. And also, based on this study, the methodologies applicable to the commercial processes including economical analysis were presented.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.1
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• pp.52-58
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• 2013

The effets of the pretreatments of tropical kapok fibers were evaluated in this study in terms of water sorption capacity and oil sorption capacity. The alkali treatments with NaOH resulted in the reduction of lignin, oil and hemicellulose, which were detected with FT-IR spectrum. The reduction of the lyphophilic components such as fat on kapok fiber by the ozone treatments were also measured with FT-IR spectrum. The oil sorption capacity of kapok fiber was decreased by the alkali treatments and the ozone treatments, while the water sorption capacity was increased. The liquid sorption capacity were greatly affected by the mechanical cutting of kapok fiber which exposed the big lumen of kapok fiber. The hydrophilic property of kapok fiber could be controlled by the pretreatments, which would increase the applicability of kapok fiber for preparation of various functional paper products.

• Korean journal of food and cookery science
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• v.15 no.3
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• pp.238-243
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• 1999

For the development of technique for isolation of naked barley starch from Youngsan variety, optimum conditions of the isolation process were investigated. The effect of blending was examined and the results showed that 29.7% starch yield was obtained by 6 times of blending. After the blending, the barley starch contained 3.2% protein, 0.7% fat, 0.4% fiber, 0.4% ash and 2.8% ${eta}$-glucan. The opitmum conditions of ${eta}$-glucanase treatment were studied and the results showed that the amount of ${eta}$-glucanase and barley flour-water ratio were 60,000 unit and 1/2, the optimum steeping temperature, pH were $45^{\circ}C$ and 6.5, respectively. The effect of alkali treatment which would be supposed to increase the yield and purity of the barley starch was also examined. 76.7% starch content was obtained by 2 hr of alkali treatment. After all the treatment of isolation process, the barley starch finally contained 0.2% protein and 0.1% ${eta}$-glucan.

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.4
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• pp.601-612
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• 2015

This research investigated the dyeing behavior of palmatine (a major coloring compound of Phellodendron bark in addition to berberine) using mercerization (M), tannic acid (T), mercerization-tannic acid (MT), and tannic acid -mercerization (TM) pretreatments. Mercerization was conducted using $20^{\circ}C$ of 20% NaOH for 5 minutes. Tannic acid treatment was conducted using 15% o.w.f. solution of tannic acid at $60^{\circ}C$ for 30 minutes and fixed with potassium antimonyl tartrate trihydrate. Dyeing was conducted using 1% o.w.f. palmatine chloride hydrate with 1:100 liquor ratio at $10-95^{\circ}C$ for 10-60 minutes in a dyebath of pH 3-9. MT method resulted in the highest dye uptake and was two times higher than the average dye uptake of T method. MT method provided the best result when the dyeing temperature was $80^{\circ}C$ or $95^{\circ}C$ and the dyeing time was 60 minutes. The pH of the dyebath had less effect on the dye uptake but a pH higher than 5 provided better results. The study confirmed that palmatine is a major coloring compound of Phellodendron bark and that the MT method can be used as a successful cotton dyeing method.

• Journal of Energy Engineering
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• v.6 no.1
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• pp.26-33
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• 1997

Highly crystalline Cu-ZSM5 was prepared without using organic templates. Several ion exchange treatments between Na$\^$＋/ and Cu$\^$2＋/ brought about excess loading of copper ions on the ZSM5 zeolite and the resultant zeolite was active for the decomposition of NO. This indicates that the copper ions excessively loaded on the ZSM5 zeolite are effective for the NO decomposition. When oxygen was added to a reactants, the conversion of NO decreased. NO, O$_2$TPD experiments explained that the active sites for NO decomposition and the adsorption sites of O$_2$, were the same. O$_2$, at the surface of ZSM5 zeolite was desorbed incompletely after pretreatment at 500$^{\circ}C$, and CU-ZSM5 pretreated with H$_2$at 500$^{\circ}C$ showed promoted activity at the start of reaction. Thus, it seems clear that O$_2$, adsorbed ai the surface of catalyst inhibits the catalytic activity.

• Journal of the Korean Wood Science and Technology
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• v.14 no.3
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• pp.23-29
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• 1986

Alakline peroxide pretreatment for the delignification of poplar wood was performed. sinceit is a simple and efficent method for enhancing the enzymatic digestibility of wood residues. Approximately one-half of their lignin and most of the hemicellulose present in poplar wood were removed when the wood sawdust was reacted at 25$^{\circ}C$ for 100 hrs in an alkaline solution (pH 11.5) of 1% peroxide. The rate of decomposition as well as the saccharification efficiency were enhanced up to 350% and 260% respectively in comparision with those of the controll. This enhancement is comparable with that pretreated with 1% sodium hydroxide and 20% peracetic acid successively. The advantages of alkaline peroxide as delignifying agents against other chemicals were also discussed.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.7
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• pp.257-262
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• 2021

Accidents caused by black ice occur frequently every winter, and the fatality rate is very high compared to other traffic accidents. Therefore, a systematic method is needed to predict the black ice formation before accidents. In this paper, we proposed a black ice prediction model based on heterogenous and multi-type data. To this end, 12,574,630 cases of 46 types of land, infrastructure, transport public data and meteorological public data were collected. Subsequently, the data cleansing process including missing value detection and normalization was followed by the establishment of approximately 600,000 refined datasets. We analyzed the correlation of 42 factors collected to predict the occurrence of black ice by selecting only 21 factors that have a valid effect on black ice prediction. The prediction model developed through this will eventually be used to derive the route-specific black ice risk index, which will be utilized as a preliminary study for black ice warning alart services.