• Journal of Pharmaceutical Investigation
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• v.3 no.1_2
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• pp.5-15
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• 1973

Fluorometric determination of dl-Methylephedrine hydrochloride from complex preparation were studied. According to the experimental results and considerations obtained the results for the following. (1) dl-Methylephedrine hydrochloride in Hydrochloric acid media occurs the fluorescens by Picrolonic acid and Cuppric acetate. (2) The maximum absorption fluorescence wave length of dl-Methylephedrine hydrochloride standard solution is $365m{\mu}$. (3) The relationship between the fluorescence proportions to concentration of standard solution at range of $4.2{\times}10^{-4}\;M$. $6{\times}10^{-4}M$. (4) dl-Methylephedrine hydrochloride was precisely determined even in the presence of various components, especially Chloropheniramine maleate, Dextromethorphan hydrobromide and Diphenylhydramine hydrochloride. (5) This method has high sensitivity and is simple in precedure. (6) This method be applicable with 99.79% accuracy and was 99.5% in complex preparation.

• YAKHAK HOEJI
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• v.19 no.1
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• pp.30-35
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• 1975

pKi values and sensitivity of acid-base indicators in the mixed solvent systems of water-alcohols and water-acetone at differential pH and in concentration media were determined by spectrophotometric method. When the concentration of the organic solvents were increased, the pKi values of sulfophthalein indicators, thymol blue and bromcresol purple, became larger whereas those of an axo indicator, methyl yellow, became smaller nad the pH values of the equivalent points of acids became smaller and the pH values of the equivalent points of acids became higher than those in the aqueous solution. potassium bicarbonate, a standard compound used in the organic solvent systems without a prerequisite procedure of expelling carbon dioxide by boiling.

• Journal of Environmental Science International
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• v.29 no.2
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• pp.201-207
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• 2020

A new chemosensor based on a self-assembled system has been devised to detect Hg²⁺ions efficiently. We demonstrated that the amphiphilic building blocks consisting of pyrene and boronic acid (1) aggregate in aqueous solutions and provide an outstanding sensing platform for sensitive detection. The self-assembled 1 exhibited high selectivity and sensitivity for Hg²⁺ion detection via fluorescence quenching, where the Hg²⁺ion detection ensued from a fast transmetallation of 1. The Stern-Volmer (SV) quenching constant for its fluorescence quenching by Hg²⁺ions was approximately 1.58 × 10⁸ M^-1. In addition, self-assembled 1 exhibited excellent sensing abilities at nano-molar concentration levels when tap water and freshwater samples were contaminated with of Hg²⁺ ions.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.5
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• pp.1338-1346
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• 1994

The objective of this study is to investigate the effect of various parameters, such as temperature, mean current density and voltage on the performance of phosphoric acid fuel cell (PAFC) by numerical analysis. Two types of flow passages, which are Z-parallel type and Z-counter type, are evaluated to obtain the best current density and temperature distribution. Parametric studies and sensitivity analysis of the PAFC system's operation in single cell are accomplished. A steady state simulation of the entire system is developed using nonlinear ordinary differential equations. The finite difference method and trial and error procedures are used to obtain a solution.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.2
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• pp.147-154
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• 1990

A sensitive method for the determination of total selenium in aerosol particles is described. The method involves dissolution of aerosol particles by $HNO_3-HClO_4$ mixed acids, pre-reduction of Se (VI) to Se (IV) by boiling hydrochloric acid, and hydride generation followed by atomic absorption detection. Dissolved Se (IV) in 4M hydrochloric acid is reacted with $NaBH_4$ to form $H_2Se$, which is subsequently collected in an U-tube cooled in liquid nitrogen. Upon the completion of $H_2Se$ generation, the collected $H_2Se$ is rapidly vaporized into a quartz cuvette burner by removing the U-tube from liquid nitrogen, atomized, and then detected by an atomic absorption spectrophotometer. The absolute sensitivity of the method is 0.49 ng/0.0044 Abs. The accuracy of the method evaluated by analyzing standard reference materials for urban aerosol is better than 10%. Analytical results for urban and rural aerosol particles are reported.

• Journal of the Korean Electrochemical Society
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• v.5 no.4
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• pp.212-215
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• 2002

A superoxide dismutase (SOD)-based superoxide ion $(O_2^-)$ sensor was fabricated by immobilizing SOD on a self-assembled monolayer (SAM) of 3-mercaptopropionic acid (MPA) which was prepared on a gold electrode. The SAM of MPA was found to function as an effective promoter for the electrode reaction of SOD. The amperometric response to $(O_2^-)$ was monitored at 300mV and -100mV vs. Ag/ Agel in 5mM phosphate buffer solution containing $KO_2$. The sensor was proved to have a high sensitivity, selectivity and short response time (<5 s) and negligible interference.

• Analytical Science and Technology
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• v.16 no.1
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• pp.78-81
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• 2003

Peptides separation in high performance liquid chromatography (HPLC) is very important for the analysis of total proteins using mass spectrometry rather than two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). In this study, we investigated the optimal HPLC condition of peptides for the use of mass fingerprinting. As a result of pursuing a combination of solvent additives for HPLC, water and acetonitile containing both 0.1% trifluoroacetic acid and 0.1% acetic acid respectively showed the most efficient resolution and sensitivity.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.05a
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• pp.236-237
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• 2001

In this study, experiments were carried out to measure the variations in the corrosion potential and current density of polarization curves with amorphous $Fe_{70}Cr_5Si_{10}B_{15}$ and $Co_{70}Cr_5Si_{10}B_{15}$ alloy ribbon. The results were particularly examined to identify the influences of corrosion potential including various conditions such as hydrochloric acid, temperature, salt, pH, and oxygen. The optimum conditions were established with variations including temperature, salt, pH, oxygen, corrosion rate, and resistance of corrosion potential. The mass tranfer coefficient(${\alpha}$) value was determined with the Tafel's slope for the anodic dissolution based on the polarization effect with optimum conditions. The second anodic current density peak and maximum passive current density were designated as the critical corrosion sensitivity($I_{r}/I_{f}$).

• Journal of the Korean Chemical Society
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• v.46 no.5
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• pp.437-471
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• 2002

The photosensitivity enhancement of photoresist achieved by the addition of acid amplifiers stems from the autocatalytic decomposition of the acid amplifiers triggered by acidic species generated from a photoacid gen-erator. In this research we synthesized and evaluated 4-hydroxy-4'-p-styrenesulfonyloxy isopropylidene dicyclohex-ane(1), 4,4'-di-p-styrenesulfonyloxy isopropylidene dicyclohexane(2) and 4-p-styrenesulfonyloxy-4'-tosyloxy isopropylidene dicyclohexane(3) as novel acid amplifiers. These acid amplifiers(1-3) showed reasonable thermal stability for resist pro-cessing temperature. As estimated by the sensitivity curve, 1-3 were 2X-12X sensitive than poly(tert-butyl meth-acrylate) film in the presence of a photoacid generator and, therefore, provides practical applicability for photoimaging.

• Journal of Electrochemical Science and Technology
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• v.8 no.4
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• pp.282-293
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• 2017

A new modified carbon paste electrode (CPE) was constructed based on nickel oxide nanoparticles (NiONPs) and graphene nanosheets (Gr) for simultaneous determination of paracetamol (PCM) and mefenamic acid (MFA) in aqueous media and pharmaceutical dosage forms. NiONPs were synthesized via a simple and inexpensive technique and characterized using X-ray diffraction method. Scanning electron microscopy was used for the characterization of the morphology of modified carbon paste electrode (NiONPs/Gr/CPE). Voltammetric studies suggest that the NiONPs and Gr provide a synergistic augmentation that can increase current responses by improvement of electron transfers of these compounds on the NiONPs/Gr/CPE surface. Using cyclic voltammetry, the NiONPs/Gr/CPE showed good sensitivity and selectivity for the determination of PCM and MFA in individually or mixture standard samples in the linear range of $0.1-30{\mu}g\;mL^{-1}$. The resulted limit of detection and limit of quantification were 20 and $60ng\;mL^{-1}$ for PCM, 24 and $72ng\;mL^{-1}$ for MFA, respectively. The analytical performance of the NiONPs/Gr/CPE was evaluated for the determination of PCM and MFA in pharmaceutical dosage forms with satisfactory results.