• Analytical Science and Technology
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• v.27 no.3
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• pp.161-166
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• 2014

Currently oxidation-reduction titration method for the assay method using the hazardous reagent, carbon tetrachloride, for cefroxadine capsules has been used in Korean Pharmaceutical Codex. We developed and validated an alternative HPLC assay method by substituting the use of the hazardous reagent, carbon tetrachloride, to the use of less toxic ones like acetonitrile. The linearity of the calibration curves in the desired concentration range was good ($r^2$ > 0.999). Relative standard deviations of intra-day precision were ranged between 0.30% and 0.69% and inter-day precision were ranged between 0.47% and 0.82%. Accuracy was obtained with recoveries in range of 100.20% and 100.56%. Developed method was applied to the determination of cefroxadine in commercial cefroxadine capsule and could be expected to become valuable tools for revising the Korean Pharmaceutical Codex.

• Journal of Korean Society of Forest Science
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• v.35 no.1
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• pp.24-32
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• 1977

According to the chlorous salt method, most of holocellulose whose lignin was removed, was obtained. In extracting xylan from holocellulose by the different densities of alkali, 5% KOH was extracted three times but still there remained part of xylan in it and another composite of hemicellulose and cellulose was obtained. The extraction of 10% and 20% KOH showed a desirable result. Rather than the ordinary method to use a large quantity of ethanol in the precipitation isolation of xylan, the method to use a small quantity of ethanol in adopting the dialysis with cellophane-membrane by condensing density to one tenth, made il possible to extract a high purity xylan in a high retrieving rate. In isolating glucomannan, the residue of 5% KOH extraction contained a large quantity of xylan, the residue of 10% and 24% KOH extraction, also showed the same result and the comparison between glucose and mannose was approximately 1 : 1. The purification of Fehling solution made it possible to obtain comparatively pure xylan but the process of oxidation dissolution was complicated and the retrieving rate was low. This was not a good method. The ethanol titration purified a high purity xylan in a high retrieving rate and was a very excellent purifying method, considering its simple and easy process. These two purifying methods, however, could not completely remove the residue of arabinose. This will be examined and reported later.

• The Journal of Korean Society of Virology
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• v.26 no.2
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• pp.181-189
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• 1996

Fecal samples of calf diarrhea were taken on farms in Jeju island, rotavirus was isolated and cytopathic effect (CPE) was determined after infection to MA104 cell. Morphological evaluation on electron microscopy proved it as rotavirus. Also, its infection to MA104 cell was reidentified using a fluorescence antibody method. Genotype of Jeju island bovine rotavirus (JBR) analyzed through PAGE was 4: 2: 3: 2 pattern, which was unique in bovine and that analyzed through general PAGE was somewhat different from NCDV, UK, KK3, A5-3A, 61A, B223 and similar to N stool-5, N culture-5 and Kawatabi (Japan). By titration after plaquing, the level was $1-3\;{\times}\;10^6\;PFU/ml$, which was lower than those of NCDV and UK. Electrophoresis analysis of RNA-RNA hybridization, ELISA, and first and second PCR products of VP7 and VP4 in 1% agarose ($TAE+1{\mu}l$ EtBr) revealed that the rotavirus was a serotype of G6P11.

• Journal of the Korean Chemical Society
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• v.30 no.5
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• pp.456-464
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• 1986

The complex formation of branched poly(ethylene imine) (BPEI) with bivalent transition metal ions, such as Fe(II), Co(II), Ni(II) and Cu(II), have been investigated in terms of visible absorption and pH titration methods in an aqueous solution in 0.1M KCl at 30${\circ}$. The stability constants for M(II)-BPEI complexes was calculated with the modified Bjerrum method. The formation curves of M(II)-BPEI complexes showed that Fe(II), Co(II), Ni(II) and Cu(II) ions formed coordination compounds with four, two, two, and two ethylene imine group, respectively. In the case of Cu(II)-BPEI complex at pH 3.4 ∼ 3.8, ${\lambda}_{max}$ was shifted to the red region with a decrease in the acidity. The overall stability constants (log $K_2$) increased as the following order, Co(II) < Cu(II) < Ni(II) < Fe(II).

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.4
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• pp.434-439
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• 2006

In this study, activated carbon(ACs) have been modified by nitric acid and heat-treatment. The surface and structure properties of ACs were determined by BET surface area, FT-IR pH and acid/base value. The changes in pore structure and surface properties of these modified ACs were correlated with natural gas adsorption which measured by volumetric apparatus at $0^{\circ}C$ and $25^{\circ}C$. The pore textural properties of activated carbon was also characterized by nitrogen adsorption at 77 K. Specific surface area and micropore volume of them were calculated by Langmuir equation and Horvath-Kawazoe method, and chemical properties of surface were measured by FT-IR and titration of acid and base solutions. Pore texture of activated carbons after treatments were not significantly changed. Total acidity increased and basicity of samples decreased. however the basicity increased with heat treatment. The methane adsorption of ACs become different depending on the acid/base value of samples.

• Journal of Environmental Science International
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• v.22 no.1
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• pp.73-81
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• 2013

The present work has been devoted to the catalytic reduction of $N_2O$ by $H_2$ with $Pt/SiO_2$ catalysts at very low temperatures, such as $110^{\circ}C$, and their nanoparticle sizes have been determined by using $H_2-N_2O$ titration, X-ray diffraction(XRD) and high-resolution transmission electron microscopy(HRTEM) measurements. A sample of 1.72% $Pt/SiO_2$, which had been prepared by an ion exchange method, consisted of almost atomic levels of Pt nanoparticles with 1.16 nm that are very consistent with the HRTEM measurements, while a $Pt/SiO_2$ catalyst possessing the same Pt amount via an incipient wetness technique did 13.5 nm particles as determined by the XRD measurements. These two catalysts showed a noticeable difference in the on-stream $deN_2O$ activity maintenance profiles at $110^{\circ}C$. This discrepancy was associated with the nanoparticle sizes, i.e., the $Pt/SiO_2$ catalyst with the smaller particle size was much more active for the $N_2O$ reduction. When repeated measurements of the $N_2O$ reduction with the 1.16 nm Pt catalyst at $110^{\circ}C$ were allowed, the catalyst deactivation occurred, depending somewhat on regeneration excursions.

• Journal of the Korean Chemical Society
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• v.16 no.3
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• pp.157-165
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• 1972

Thermal decomposition of ammonium metavanadate has been investigated by using the quartz spring balance and differential thermal analysis. It showed that the decomposition of ammonium metavanadate is proceeded at two stages which correspond to $180^{\circ}C-220^{\circ}C$ and $310^{\circ}C-330^{\circ}C$ decomposition temperatures, respectively. Evolved ammonia gas in thermal decomposition has been analyzed quantitatively by titration. And the constituents of gases evolved have been evaluated by gas chromatography and omegatron spectrometer. From these results, it was concluded that the gases evolved in the first step decomposition were $NH_3$ and $H_2O$ with 2:1 ratio and the second step decomposition corresponded to the formation of $NH_3$, $H_2O$ and $N_2O$ which was produced in oxidation of $NH_3$ by $V_2O_5$. The decomposition products were identified by means of X-ray diffraction method. The decomposition product in air was V_2O_5 and the product in vacuum $V_3O_7.$ The kinetics of the thermal decomposition was studied, giving the values of the activation energy of 41.4 kcal/mole and 64.4 (kcal/mole) respectively.

• Journal of the Korean Chemical Society
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• v.51 no.1
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• pp.21-30
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• 2007

A multiwavelength spectrophotometric titration method was applied to study protolytic constants of four water-soluble vitamins, folic acid(vitamin B9 or B0), thiamine(vitamin B1), riboflavin(vitamin B2) and pyridoxal (vitamin B6) in binary ethanol-water mixtures at 25oC and an ionic strength of 0.1M NaNO3. The protolytic equilibrium constants, spectral profiles, concentration diagrams and also the number of components has been calculated from the curve fitting of the pH-absorbance data with appropriate mass balance equations by an established factor analysis model. DATAN program was used for determination of acidity constant and SPECFIT program was used for calculation of standard deviations and partial correlation coefficients. A glass electrode calibration procedure based on the four parameter equation pH=α+SpcH+JH+[H+]+ JOH-Kw/[H+] based on the Gran,s plots was used to obtain pH-readings in the concentration scale (pcH). The effect of the solvent on the protolytic constants was discussed.

• Transactions of the Korean hydrogen and new energy society
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• v.24 no.2
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• pp.160-171
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• 2013

$LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ powder for cathode materials in lithium rechargeable batteries was treated by atmospheric plasma containing hydrogen to investigate the relationship between charge/discharge performance and physical/chemical changes of materials. Hydrogen plasma at atmosphere pressure was irradiated on the surface of active materials, and the change for their crystal structure, surface morphology, and chemical composition were observed by XRD, SEM-EDS and titration method, respectively. The crystal structure and surface morphology of $H_2$ plasma-treated powders were not changed but their chemical compositions were slightly varied. For charge/discharge test, $H_2$ plasma affected initial capacity and rate capability of active materials but continuous cycling was not subject to plasma treatment. Therefore, it was observed that $H_2$ plasma treatment affected the surface of materials and caused the change of chemical composition.

• Korean Journal of Biological Psychiatry
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• v.9 no.2
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• pp.129-139
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• 2002

Objective:This study was performed to investigate the prescribing patterns of antimanic agents in the treatment of acute bipolar disorder inpatients in Korea from 1990 through 2000. The results will serve as the basic data for the practice guideline for the pharmacotherapy of bipolar disorder patients in Korea. Method:Retrospective chart review of bipolar disorder inpatients of Soonchunhyang Medical Center in Seoul and Chun-An was conducted for each of the year 1990, 1995, and 2000. The following data are collected ; 1) demographic data, 2) history of bipolar disorder, 3) length of hospital stay, 4) detailed drug titration records of antimanic agents and antipsychotic agents. Results:During the last decade, the frequency of lithium monotherapy was decreased obviously. Instead, more than half of the patients in 2000 were on combination therapy of lithium and anticonvulsants. Lithiumvalproate combination was the preferred strategy and the use rate of carbamazepine has been decreased. In addition, most of the patients were given antipsychotic agents during the last 10 years. And recently, atypical antipsychotics were increasingly prescribed. These changes in the field of pharmacology of bipolar disorder have resulted neither in shorter hospital stays nor lower dosages of concurrent neuroleptics. Conclusions:The results indicate the trends in the prescribing of antimanic agents for the treatment of bipolar disorder in Korea across the past 10 years. Mostly, the change seems to correspond to the international practice guideline. More systematic research is needed to find out the clinical benefits of the anticonvulsants in the real practice of treatment of bipolar disorder.