• Microbiology and Biotechnology Letters
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• v.35 no.4
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• pp.334-338
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• 2007

The disinfection effects of trichloroisocyanuric acid (TICA), calcium hypochlorite (CH), and Bromochlorodimethylhydantoin (BCDMH) on various bacteria in aqueous suspension were comparatively characterized at various concentrations and exposure times of each disinfectant. When various bacteria cells ($10^8\;CFU/ml$) including Escherichia coli, Pseudomonas aeroginosa, Enterococcus faecalis, Bacillus cereus, Legionella pneumophila, and Staphylococcus aureus were exposed with a solution containing 8 ppm each of TICA, a 99% of the initial cells were killed in 60 sec, 368 sec, 372 sec, 506 sec, 812 sec, and 909 sec, respectively. In addition, the minimum exposure time required to kill 99% of E. coli ($10^8\;CFU/ml$) with 8 ppm of each TICA, BCDMH and CH was measured at 60 sec, 114 sec, and 7,100 sec, respectively. These comparative studies demonstrate that disinfection efficacy is highly variable depending on microbial species as well as disinfectant type, concentration, and exposure time.

• Journal of Korea Soil Environment Society
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• v.4 no.1
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• pp.49-55
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• 1999

The treatment of petroleum contaminated soil requires various physico-chemical remediation technologies which are efficient in time and can reduce the possibility of secondary contamination by themselves In this study, an innovated soil washing process was proposed to treat the diesel-contaminated soil. Micro-bubbles, which were generated by hydrogen peroxide, deserted and floated the contaminants. Soils less than #60(0.25mm) were artificially contaminated by 6,500mg TPH/kg dry soil initially. The process was examined for pH, the soil to water mixing ratio, concentration of $H_2O$$_2$, and contacting times. In the case of less than #60 soil, maximum removal efficiency(60%) was obtained at pH 12. 1.0% hydrogen peroxide, and 1 : 5 soil to water mixing ratio for 1 hour.

• Korean Journal of Materials Research
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• v.26 no.9
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• pp.468-471
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• 2016

$SnO_2:CNT$ thick films for gas sensors were fabricated by screen printing method on alumina substrates and were annealed at $300^{\circ}C$ in air. The nano $SnO_2$ powders were prepared by solution reduction method using tin chloride ($SnCl_2.2H_2O$), hydrazine ($N_2H_4$) and NaOH. Nano $SnO_2:CNT$ sensing materials were prepared by ball-milling for 24h. The weight range of CNT addition on the $SnO_2$ surface was from 0 to 10 %. The structural and morphological properties of these sensing material were investigated using X-ray diffraction and scanning electron microscopy and transmission electron microscope. The structural properties of the $SnO_2:CNT$ sensing materials showed a tetragonal phase with (110), (101), and (211) dominant orientations. No XRD peaks corresponding to CNT were observed in the $SnO_2:CNT$ powders. The particle size of the $SnO_2:CNT$ sensing materials was about 5~10 nm. The sensing characteristics of the $SnO_2:CNT$ thick films for 5 ppm $H_2S$ gas were investigated by comparing the electrical resistance in air with that in the target gases of each sensor in a test box. The results showed that the maximum sensitivity of the $SnO_2:CNT$ gas sensors at room temperature was observed when the CNT concentration was 8wt%.

• Korean Journal of Materials Research
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• v.16 no.5
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• pp.277-284
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• 2006

The alloys were prepared by a non-consumable vacuum arc melting and homogenized at $1050^{\circ}C$ for 24 hrs. Two kind of surface modifications were performed alkali treatment in 5.0M NaOH solution subsequent and heat treatment in vacuum furnace at $600^{\circ}C$, and were oxidizing treatment at the temperature range of 550 to $750^{\circ}C$ for 30 minutes. After surface modification, these samples were soaked in SBF which consists of nearly the same ion concentration as human blood plasma. Cytotoxicity tests were performed in MTT assay treated L929 fibroblast cell culture, using indirect methods. A porous and thin activated layer was formed on Titanium and Ti-8Ta-3Nb alloy by the alkali treatment. A bone-like hydroxyapatite was nucleated on the activated porous surfaces during the in vitro test. However, Ti-8Ta-3Nb alloys showed better bioactive properties than Titanium. According to XRD results, oxide layers composed of mostly $TiO_2$(rutile) phases. Cytotoxicity test also revealed that moderate oxidation treatment lowers cell toxicity and Ti-8Ta-3Nb alloy showed better results compared with Titanium.

• Carbon letters
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• v.25
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• pp.14-24
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• 2018

Electrochemical properties and performance of composites performed by incorporating metal oxide or metal hydroxide on carbon materials based on graphene and carbon nanotube (CNT) were analyzed. From the surface analysis by field emission scanning electron microscopy and field emission transmission electron microscopy, it was confirmed that graphene, CNT and metal materials are well dispersed in the ternary composites. In addition, structural and elemental analyses of the composite were conducted. The electrochemical characteristics of the ternary composites were analyzed by cyclic voltammetry, galvanostatic charge-discharge tests, and electrochemical impedance spectroscopy in 6 M KOH, or $1M\;Na_2SO_4$ electrolyte solution. The highest specific capacitance was $1622F\;g^{-1}$ obtained for NiCo-containing graphene with NiCo ratio of 2 to 1 (GNiCo 2:1) and the GNS/single-walled carbon $nanotubes/Ni(OH)_2$ (20 wt%) composite had the maximum specific capacitance of $1149F\;g^{-1}$. The specific capacitance and rate-capability of the $CNT/MnO_2/reduced$ graphene oxide (RGO) composites were improved as compared to the $MnO_2/RGO$ composites without CNTs. The $MnO_2/RGO$ composite containing 20 wt% CNT with reference to RGO exhibited the best specific capacitance of $208.9F\;g^{-1}$ at a current density of $0.5A\;g^{-1}$ and 77.2% capacitance retention at a current density of $10A\;g^{-1}$.

• YAKHAK HOEJI
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• v.38 no.3
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• pp.250-264
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• 1994

Omeprazole(OMZ)-cholestyramine(CHL) and various OMZ-Dowex resin complexes were prepared by reaction between OMZ and activated resins in 0.1N NaOH solution. And their physical properties were tested by means of infrared(IR), differential scaning caloimeter(DSC), X-ray diffraction. Chemical stability of OMZ-CHL was increased markedly compared with OMZ and the decomposition of OMZ-CHL followed the pseudo first-order kinetics and the rate constants were $2.743{\times}10^{-4}/day$ at $20^{\circ}C$, $7.83{\times}10^{-3}day^{-1}$ under 80% RH and $1.68{\times}10^{-2}day^{-1}$ under UV radiation, respectively. On the other hand, the rate constants of OMZ were $2.996{\times}10^{-4}day^{-1}$ at $20^{\circ}C$, $1.17{\times}10^{-2}day^{-1}$ under 85% RH, and $4.07{\times}10^{-2}day^{-1}$ under UV radiation, respectively. The rates of dissolution of OMZ-CHL bulk and OMZ-CHL tablet were 100% and more than 85% in 15 minutes, respectively, which were increased than OMZ base and OMZ-tablet. In the acute toxicological test, the value of oral $LD_{50}$(mouse) was 4.608 g/kg. OMZ-CHL was pelletized using lactose, polyethyle neglycol(PEG), D-sorbitol, Avicel PH 101, sodium laurylsulfate and polyvinylpyrrolidone(PVP) K-30, and enteric coated with HPMCP, Myvacet, acetone, ethanol and cetanol, of which dissolution rate was found to be more than 85% in 10 minutes. From the above results, it was found that OMZ-CHL is a useful means for development of new oral dosage forms of OMZ.

• YAKHAK HOEJI
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• v.41 no.2
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• pp.161-173
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• 1997

Tuber of Aconitum chiisanense(Ranunculaceae) a specific medicinal plant in Korea, which is known to have the activity to recover reduced metabolism of feeble patients and has been used to symptoms such as pain, paralysis, atonia and coldness of extremities, etc. were studied. The powdered tubers of the plant were extracted with 10% EtOH 3 times and the combined extract was dissolved in 1N HCl solution and washed with ethyl acetate. The aqueous layer was basified with solid $Na_2CO_3$ and extracted with $CHCl_3$ to obtain an alkaloidal fraction. The alkaloidal fraction was subjected to column chromatography using silica gel, alumina and Sephdex LH 20, etc. From the alkaloidal fraction, five diterpene alkaloids, mesaconitine, aconitine, hypaconitine, 8-O-ethyl 14-benzoylmesaconine and talatizamine, were isolated and identified on the basis of their physico-chemical properties and spectroscopic evidences($^1H$-, $^{13}C$-NMR, EI-MS, IR, 2D-NMR) respectively. Especially the Compound IV, 8-O-ethyl 14-benzoylmesaconine, was assumed to be an artifact resulting from mesaconitine during extraction procedures. The contents of mesaconitine, aconitine and hypaconitine in the mother tuber of this plant were 0.300%, 0.024%, and 0.068%. And that of the attached tuber(new one) of this plant were 0.336%, 0.034% and 0.240% respectively.

• 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.

• Textile Coloration and Finishing
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• v.10 no.4
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• pp.37-44
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• 1998

The purpose of this study was to elucidate the effect of weight loss of polyethylene terephthalate(PET) fabrics on the mechanical properties such as bending and shear. In order to compare the effect of treatment machine on the mechanical properies of treated PET fabrics, PET fabrics were hydrolyzed with NaOH aqueous solution using Tank machine and Liquor flow machine, respectively. The results were as follows ： 1. The bending rigidity and shear stiffness of hydrolyzed PET fabric decreased markedly up to about 10％ weight loss regardless of treatment machines. At the above 10％ weight loss, the variation of these properties is nearly unchanged. In addition, the bending hysteresis and shear hysteresis also showed similar trend. 2. Weft density change of PET fabrics treated with Liquor flow machine decreased by 1pick/inch. It is assumed that this is attributed to the tension during the treatment of Liquor flow machine. On the other hand, the weft density change of PET fabrics treated with Tank machine is scarcely influeneced by the weight loss. While warp density of PET fabrics treated with Liquor flow machine had no change with weight loss, warp density of PET fabrics treated with Tank machine decreased by 6pick/inch due to the tension. 3. The bending rigidity and shear stiffness of PET fabrics hydrolyzed with liquor flow machine slightly higher than with Tank m/c at the above 10％ weight loss. It is assumed that this is caused by the increasement of the crossing pressure of warp and weft yarn and contact points of filaments in the yarns. Also, the bending and shear hysteresis of PET fabrics treated with Tank machine were higher than that of liquor flow machine.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.168-175
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• 2018

In order to investigate the effect of the chemical treatment of bamboo fiber on physical properties of polypropylene (PP)/bamboo fiber (BF) composites, silane coupling agents such as ${\gamma}$-aminopropyltriethoxysilane (APS), ${\gamma}$-glycidoxypropyl-trimethoxysilane (GPS) and ${\gamma}$-mercaptopropyltrimethoxysilane (MRPS) were applied to BF and alkaline treated BF. Morphological properties of the chemically treated BF were confirmed by optical microscope and SEM measurements, and chemical structure changes were confirmed by FT-IR and EDS. TGA results showed that the thermal stability of silane treated BF increased. Based on the analysis of a universal testing machine and an Izod impact test, the flexural and impact properties of PP/silane treated BF composites showed higher values than those of PP/BF composites. The enhancement of interfacial adhesion properties of the PP/BF composite was checked from SEM images of the fracture of specimens after the tensile test.