• Bulletin of the Korean Chemical Society
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• v.28 no.7
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• pp.1104-1108
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• 2007

Conducting Polypyrrole-lead titanate (PPy/PbTiO3) composites have been prepared by in situ deposition technique by placing different wt.% of fine grade powder of PbTiO3 (10, 20, 30, 40, and 50%) during polymerization of pyrrole. The composites formed were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), and these data indicate that PbTiO3 particles are dominating with an increase in crystallinity as well as thermal stability of the composites. The results on the low frequency dielectric studies which are obtained in the form of pressed pellet state are interpreted in terms of Maxwell Wagner polarization, which are responsible for the dielectric relaxation mechanism and frequency dependence of conductivity.

• Applied Biological Chemistry
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• v.41 no.2
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• pp.153-159
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• 1998

A possibility of evaluation of the major internal quality factors-Brix, moisture contents, firmness and acid content in the Korean domestic 'Fuji'apple fruits by near-infrared reflectance spectroscopic (NIRS) methods were investigated. A multiple linear regression(MLR) analysis between the data obtained by physico- chemical analysis method using refractometer, freeze drier, texture analyzer and titrater and NIR spectral data was carried out to make a calibration. The standard error of prediction(SEP) of Brix, moisture, firmness and acid content were $0.50^{\circ}Brix,\;0.64%,\;0.14kg/cm^2$ and 0.07%. It is concluded that NIRS methods can be used to evaluate Brix and moisture contents of in a apple non-destructive and rapid way but the accuracy for determination of firmness and acid content was slightly low.

• International Journal of Advanced Culture Technology
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• v.11 no.1
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• pp.376-388
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• 2023

After a longitudinal analysis of the data on the college entrance examination of students enrolled in the Department of Chemistry Education at Gyeongnam from 2014 to 2021, the effect on the academic achievement of general chemistry according to the type of college entrance examination was studied. And the impact on the academic achievement of general chemistry according to the type of admission screening in face-to-face and non-face-to-face teaching-learning was also studied. As a result of analyzing the academic achievement of general chemistry by admission process, students admitted through occasional screening showed relatively high grades of A and B at 88.7%, and the ratio of grades of 1~3 of chemistry I in high school was high. On the other hand, in the case of students admitted through regular admission, the ratio of grades of A and B in general chemistry was very high at 94.3%, and the ratio of grades of 3~4 in chemistry I of the College Scholastic Ability Test was high. As a result of analyzing the academic achievement of general chemistry by class type and admission process, it was found that the grades of chemistry I by face-to-face classes had an effect on the academic achievement of general chemistry in non-face-to-face classes. In both admissions, the academic achievement of general chemistry by face-to-face classes was relatively higher than that of non-face-to-face-to-face classes.

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.668-678
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• 2017

Intermolecular interactions were studied for binary mixtures of 2-propanol + cyclohexane, n-hexane, benzene, toluene, o-, m- and p-xylenes by measuring ultrasonic speeds (u) over the entire range of composition at 298.15 K and 308.15 K. From these results the deviation in ultrasonic speed was calculated. These results were fitted to the Redlich-Kister equation to derive the binary coefficients along with standard deviations between the experimental and calculated data. Acoustic parameters such as excess isentropic compressibility ($K_s^E$), intermolecular free length ($L_f$) and available volume ($V_a$) were also derived from ultrasonic speed data and Jacobson's free length theory. The ultrasonic speed data were correlated by Nomoto's relation, Van Dael's mixing relation, impedance dependence relation, and Schaaff's collision factor theory. Van Dael's relation gives the best prediction of u in the binary mixtures containing aliphatic hydrocarbons. The ultrasonic speed data and isentropic compressibility were further analyzed in terms of Jacobson's free length theory.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.536-541
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• 2018

Excess molar volumes ($V_m^E$) of binary mixtures of 1-propanol or 2-propanol (1) + cyclohexane or n-hexane (2) were measured with V-shaped dilatometer at 303.15 K. The $V_m^E$ data for these mixtures varied as: 2-propanol > 1-propanol and were higher for cyclohexane than n-hexane for both propanol systems. The experimental data were correlated with Redlich-Kister polynomial. The $V_m^E$ data were interpreted qualitatively as well as quantitatively in terms of Flory-Treszczanowicz-Benson model and Prigogine-Flory-Patterson theory. Both models correctly described the sign and shape of $V_m^E$ vs $x_1$ curves. The values calculated by both the models agree well with the experimental data.

• Korean Journal of Veterinary Pathology
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• v.1 no.1
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• pp.46-52
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• 1997

The hematology and clinical chemistry data based on the well defined normal data are essential in the safety assessment. It is important that normal values of cliniclal pathology parameters would be optimized to be accurate. So the purpose of this experiment was to compare the ranges of normal data in hematology value and serum chemistry between both sexes of F344 and Wistar rats at 5, 10, 20, 40 and 90 weeks. of age. The neutrophils eosinophils and monocytes increased with age in male Wistar rats. And serum total bilirubin and potassium were highest and alkaline phosphatase was lowest at 90 weeks in Wistar rats. As compared with Wistar rat the serum aspartate aminotransferase of F344 rats increased with age in both sexes but inorganic phosphorus decreased with age. The serum alkaline phosphatase decreased with age and potassium was highest at 90weeks. These normal data would be useful in improving the accuracy of clinical pathology value in the safety assessment.

• Journal of the Korean Chemical Society
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• v.28 no.3
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• pp.185-193
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• 1984

At the spermine concentration to cover the number of the binding site of spermine 0.016 per nucleotide, the Hill coefficient of the ethidium binding to the calf thymus DNA was 1.7, while the value was 0.38 in the absence of the spermine. On the basis of the data, together with other present data on the viscometric titration of the DNA with spermine and anomalous absorbance-temperature profile at 260nm and viscosity-temperature profile, it can be speculated that allosteric propagation of the conformational transition induced by the binding of the spermine may be involved in the monomolecular collapse of the DNA to a condensed structure.

• Carbon letters
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• v.12 no.3
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• pp.143-151
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• 2011

Bagasse fly ash (BFA) is one of the important wastes generated in the sugar industry; it has been studied as a prospective low-cost adsorbent in the removal of congo red (CR) from aqueous solutions. Chemical treatment with $H_2O_2$ was applied in order to modify the adsorbability of the raw BFA. Batch studies were performed to evaluate the influence of various experimental parameters such as dye solution pH, contact time, adsorbent dose, and temperature. Both the adsorbents were characterized by Fourier-transform infrared spectrometer, energy-dispersive X-ray spectrophotometer and nitrogen adsorption at 77 K. Equilibrium isotherms for the adsorption of CR were analyzed by Langmuir, Freundlich and Temkin models using non-linear regression technique. Intraparticle diffusion seems to control the CR removal process. The obtained experimental data can be well described by Langmuir and also followed second order kinetic models. The calculated thermodynamic parameters indicate the feasibility of the adsorption process for the studied adsorbents. The results indicate that BFA can be efficiently used for the treatment of waste water containing dyes.

• Natural Product Sciences
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• v.24 no.3
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• pp.213-218
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• 2018

Chemical investigation of the plant Tristemma hirtum P. Beauv (Melastomataceae) resulted to the isolation of a new flavonol glycoside named quercetin-7-O-${\alpha}$-D-arabinofuranoside (1), together with nine known compounds including 3'-hexadecanoyl-2'-(9aZ)-tetradecanoyl-glycerol 1'-O-[${\beta}$-D-galactopyranosyl-(1'' ${\rightarrow}$ 6'')-${\alpha}$-D-galactopyranoside] (2), arjunolic acid (3), ${\beta}$-sitosterol-3-O-${\beta}$-D-glucopyranoside (4), terminolic acid (5), quercetin (6), asiatic acid (7), maslinic acid (8), $1{\beta}$-O-galloylpedunculagin (9) and 6-hydroxyapigenin 7-O-${\beta}$-D-glucopyranoside (10) from the methanol extract using normal and reversed phase column chromatography. The structures of these compounds were determined by comprehensive interpretation of their spectral data mainly including 1D- 2D-NMR ($^1H-^1H$ COSY, HSQC, and HMBC) spectroscopic and ESI-TOF-MS mass spectrometric analysis.

• Journal of the Korean Magnetic Resonance Society
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• v.20 no.1
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• pp.13-16
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• 2016

Various experiments using zebrafish have been highlighted recently in the scientific community. Because it is possible to conduct practical experiment from various neurological research to area of genetic study or toxicity experiment. However, gender difference effects are nearly not considered. If the gender differences of zebrafish are considered it is possible to obtain more accurate data. In this study, zebrafish which have different genders were compared each other with NMR-based metabolomics. The extracts of male and female zebrafish were measured by 600 MHz NMR spectrometer. Statistical analysis and target profiling were conducted. As a result, muscle related metabolites were observed in male zebrafish and nerve related metabolites were observed in female zebrafish.