• Analytical Science and Technology
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• v.19 no.2
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• pp.181-187
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• 2006

This study was carried to survey the removal characteristics of BPA using coagulation process by PAC and PAHCS. BPA removal for PAC and PAHCS was 20.4 with 8.7 Al mg/L and 6.8 Al mg/L, respectively. Removal of BPA was lower than $UV_{254}$ and DOC but removal characteristics were similar. BPA removal for PAC and PAHCS was most high in pH 6.5 and 7.0 respectively. The time for removal by mixing time was 40 min in PAC and 30 min in PAHCS. When powdered activated carbon 50 mg/L was added in coagulation process, a high remove of BPA (61%) was noticed. Specially BPA was highly increase powdered activated carbon 5 mg/L alone. These results will be appliable in the conventional water treatment plants for improvement of water treatment system.

• Korean Journal of Medicinal Crop Science
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• v.9 no.1
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• pp.21-25
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• 2001

Major saponins in ginseng were analysed using reverse phase high performance liquid chromatography with binary mobile phase gradient control system instead of normal phase column. The optimum condition were as following : reverse phase column; ${\mu}{\beta}ondapak\;C_{18}$ column (Waters, $3.9mm{\times}300\;mm,\;5{\mu}m$), methyl cyanaide/water binary mobile phase gradient control system, solvent flow rate; 1.5 ml/min, and UV($203{\mu}m$ ) detector. The complete separation of ginsenoside $Rb_1,\;Rb_2,\;Rc,\;Rd,\;Re,\;Rf\;and\;Rg_1$ was achieved within 55 min. The Regression coefficients of the calibration curves for seven ginsenosides were 0.99.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.244-254
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• 2014

The interactions of 4-chlorobenzoic acid with the micellar system of various cationic, nonionic, and mixed surfactant systems were studied by the UV/Vis spectrophotometric method. The solubilization constants ($K_s$) of 4-chlorobenzoic acid into those micellar systems have been measured at various temperatures and various thermodynamic parameters for the solubilization of 4-chlorobenzoic acid have been calculated and analyzed from those changes. The results show that the values of ${\Delta}G^o_s$ are all negative within the measured temperature range and that the values of ${\Delta}H^o_s$ and ${\Delta}S^o_s$ are all positive. The effects of alkyl-group's length of surfactant molecules on the solubilization of 4-chlorobenzoic acid have been also measured. The values of $K_s$ were dependent simultaneously on the alkyl-group's length and the kind of head-group in surfactant molecules. From these changes we can postulate the solubilization site and the degree of interaction of 4-chlorobenzoic acid with the micellar systems.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2737-2742
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• 2011

Ring-opening metathesis polymerization (ROMP) of an ethyl-substituted tetracyclododecene (8-ethyltetracyclo[$4.4.0.1^{2,5}.1^{7,10}$] dodec-3-ene, Et-TCD) was carried out in the presence of a ternary catalyst system consisting of $WCl_6$, triisobutyl aluminium (iso$Bu_3Al$), and ethanol. The optimal molar ratio of Et-TCD/$WCl_3$/iso-$Bu_3Al$/ethanol was found as 500/1/3/2 at which the yield of ring-opened polymer was 100%. 1-Hexene was shown to be an effective molecular weight controlling agent for ROMP reaction of Et-TCD. The hydrogenation of the ring opened polymer (p-Et-TCD) was conducted successfully using Pd(5 wt %)/${\gamma}$-$Al_2O_3$ at $80^{\circ}C$ for 1 h. Chemical structures of p-Et-TCD and its hydrogenated product($H_2$-p-Et-TCD) were characterized using 2D NMR techniques ($^1H-^1H$ COSY and $^1H-^{13}C$ HSQC). The changes of physical properties such as thermal stability, glass transition temperature and light transmittance after the hydrogenation were also investigated using TGA, DSC, and UV.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3755-3760
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• 2012

Single crystals of lithium potassium phthalate (LiKP) were successfully grown from aqueous solution by solvent evaporation technique. The grown crystals were characterized by single crystal X-ray diffraction. The lithium potassium phthalate $C_{16}\;H_{12}\;K\;Li_3\;O_{11}$ belongs to triclinic system with the following unit-cell dimensions at 298(2) K;$a=7.405(5){\AA}$;$b=9.878(5){\AA}$;$c=13.396(5){\AA}$;${\alpha}=71.778(5)^{\circ}$;${\beta}=87.300(5)^{\circ}$;${\gamma}=85.405(5)^{\circ}$; having a space group P1. Mass spectrometric analysis provides the molecular weight of the compound and possible ways of fragmentations occurs in the compound. Thermal stability of the crystal was also studied by both simultaneous TGA/DTA analyses. The UV-Vis-NIR spectrum shows a good transparency in the whole of Visible and as well as in the near IR range. Third order nonlinear optical studies have also been studied by Z-scan technique. Nonlinear absorption and nonlinear refractive index were found out and the third order bulk susceptibility of compound was also estimated. The results have been discussed in detail.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.337-349
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• 2016

In this study, an analytical method to evaluate the quality of isoflavonoid compounds purified and isolated from the fruits of Cudrania tricuspidata was developed and validated using Ultra Performance Liquid Chromatography (UPLC). The fruits of C. tricuspidata were extracted with methanol and further fractioned with n-hexane, ethyl acetate and water. The resulting ethyl acetate extract separated into four isoflavonoid compounds by a combination of silica gel and sephadex LH-20 column chromatography. The structures of the compounds were elucidated as alpinumisoflavone, 6,8-diprenyl genistein, 6,8-diprenyl orobol, 4'-O-methylalpinumisoflavone by various techniques such as UV-Vis, ESI-MS, $^1H\;NMR$ and $^{13}C\;NMR$ spectroscopy. Finally, a method to characterize the compounds was developed by using the UPLC equipped with a $C_{18}$ column and a gradient mobile phase system consisting of 2% acetic acid in water (solvent A) and 2% acetic acid in methanol (solvent B). The developed method was validated with the parameters such as selectivity, linearity, limit of detection, limit of quantitation, accuracy, and precision, which are defined by the ICH (International Conference on Harmonization). Using the validated method, the compounds in the fruits harvested in different months were also quantitatively analyzed. We propose this approach this approach can readily be utilized as an efficient evaluation method to quantify the extracts of C. tricuspidata.

• Applied Chemistry for Engineering
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• v.18 no.4
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• pp.330-336
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• 2007

In this study, new dinuclear chiral Co (salen) complexes bearing $BF_3$ have been synthesized and their properties as the asymmetric catalyst have been examined. The NMR, UV and ESCA analyses were performed to determine the structure of synthesized catalysts. Their catalytic activity and selectivity have been demonstrated for the asymmetric ring opening of various terminal epoxides by hydrolytic kinetic resolution technology. The easily prepared dimeric complexes exhibited very high enantioselectivity for the asymmetric ring opening of epoxides with $H_2O$ nucleophile, providing enantiomerically enriched terminal epoxides (> 99 %ee). The dimeric structured chiral salen showed remakablely enhanced reactivity and may be employed substantially lower loadings than its monomeric analogues, and in addition no racemization happened during the separation of product epoxides. The system described in this work is very efficient for the sinthesis of chiral epoxide and 1,2-diol intermediates.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.19 no.1
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• pp.20-30
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• 1993

Liquid Chromatographic behavior of Pd(II) in Isonitosoethylacetoacetate imine IEAA-NR: R=H, CH3, C2H5, n-C3H7, n-C4H9, C6H5-CH2) Chelates were investigated by reversed phase high performance 1iquid chromatography on Micropak MCH-5 Column using Methanol /water as mobile phase. The optimum condition for the separation of Pd-Isonitrosoethylacetoacetate imine chelates were examined with respect to the flow rate, mobile phase strength. It was found that Pd(IEAA-NR)2 chelates were eluted in an acceptable range of the capacity factor value (0 $\leq$ log k' $\leq$ 1), The dependence of the logarithm of capacity factor(k') on the volume fraction of water in mixture with in the binary mobile phase was examined. Also, the dependence of k'on the liquid-liquid extraction distribution constant in methanol-water / n-alkane extraction system was on system was invert tigated for Pd(IEAA-NR)2. Both kinds of dependence are linear, which suggests that the retention of the electroneutral metal chelates be largely due to the solvophobic effect.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1164-1167
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• 2003

Recently CRT is getting flatted, As change of CRT trend from normal type to Flat type, the material of Shadow Mask was also changed from AK(Aluminum Killed) to Invar(Fe-Ni alloy) materials Until now we have used just AK(Aluminum Killed) for normal type TV(not flat type), but main raw material of shadow mask component was changed. . However recently Invar(Fe-Ni alloy) materials, which has advantage of Low Thermal Expansion and High Strength, has been developed as well as applying in mass production as CRT's trend has become more flat and fine pitch. As main raw material of shadow mask component was changed, conditions of process were changed. One of them, the importance of pre-etching process (assistant process for developing & etching) is improved because there are so many particles in the pre-etching bath because of Ni compounds. Since the solubility of Ni in pre-etching solvent is very low related to Fe's, so the compounds of Ni happen to make particles.(the solubility of Fe is twenty times Ni's) that particles happen to make process troubles and NG productions so to clear the particles we had to established high cost filtering system, but it is useless. As time goes by the quantity of particles (Ni compounds) was increased because of the capability of filtering system was not enough, the particles was produced continuous in bath, and it make quality problems. Hence we tried to develop the new pre-etching solution to remove the particles (Ni compounds) and to cost down the filtering system's running cost. But in improving the solution we discovered the new pre-etching solution made the PR developing better. In former solution there were three kinds of chemistry (COOH)2 , H2O2 , H2S04 .first the function of (COOH)2 is drilling the surface of Invar, during this mechanism Ni compounds occurred. Second the function of H202 is removing the PR fringe (half UV exposure zone on PR(PVA)), Third the function of H2S04 is the catalysis of (COOH)2 In those, (COOH)2 was the main reason to make the Ni compounds. So to improve the solutions we had to change (COOH)2 to the other material. the chemistry we improved was a complex chemistry based on H2S04 . after using this chemistry the particles problem was disappeared and there was another advantage cut down the PR fringe. The New solution made the function of H202 better so the PR developing improved. To be direct the catalyst of the new solution helped the H202. anyway First thing after change the solution the quality of shadow Mask for flat color TV was improved & the yield also improved. But the more important thing is how to control the new solution. So we accepted the new concept which was the degree of freshness. The degree of freshness is based on non-reacted solution which was 100% ( the degree of freshness) and calculated the melted Ni quantity as time goes by. So we made the gauging liner plot. In conclusion, many companies tried to make fine pitched Shadow Mask ,generally to make quality jump up it needed a lot of cost & persons .in this case the shift of core material made it possible.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.297-304
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• 2013

Free-radical copolymerization of glycidyl methacrylate(GMA) and N-phthalimidoethyl acrylate(NPEA) were carried out at $60^{\circ}C$ in dimethylformamide(DMF) solution in the presence of benzoylperoxide(BPO) at low conversion. The polymers were characterized by IR and $^1H$-NMR. The compositions of the copolymer was analyzed by ultra violet(UV/Vis) spectrophotometry. The reactivity ratios of the monomer was determined by the application of Fineman-Ross(FR) and Kelen-T$\ddot{u}$d$\ddot{o}$s(KT) methods. The monomer reactivity ratios of the system and Alfrey-Price's resonance effect(Q) and polar effect(e) value for NIEA were determined as follow. The reactivity ratios of the monomer obtained from FR and KT are found to be $r_1$=0.87, $r_2$=0.98 and $r_1$=0.88, $r_2$=0.99 respectively. The Q and e values of poly(GMA-co-NPEM) calculated from $r_1$ and $r_2$ was Q= 1.31, e=0.75 respectively.