• Korean Journal of Pharmacognosy
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• v.25 no.1
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• pp.35-40
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• 1994

Aqueous extreact of fresh ginseng (AFG) was examined for the antigenicity in Hartley guinea pigs in comparision with ovalbumin (OVA). When guinea pigs were sensitized with AFG emulsified with complete Freund's adjuvant (CFA), these animals showed negative reactions in active systemic anaphylaxis (ASA), active cutaneous anaphylaxis (ACA) and passive cutaneous anaphylaxis (PCA) tests and passive hemagglutination (PHA) reaction. On the contrary, when guinea pigs were sensitized with OVA emulsified with CFA as positive controls, these animals disclosed positive reactions in ASA, ACA and PCA tests and PHA reaction. From these results, AFG was considered not to possess antigenic properties in guinea pigs. In addition, the dose levels of AFG empolyed in the present experiment were confirmed not to suppress immune reactions.

• Bulletin of the Korean Chemical Society
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• v.16 no.5
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• pp.392-397
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• 1995

o-Phenylenediamine (o-PD) was electropolymerized on glassy carbon electrodes under a potential cycling condition. The resulting polymer films mediated electrons for the reduction of molecular oxygen at pH=1.0. It was found from the RDE, RRDE, and cyclic voltammetry experiments that the modified electrodes reduce oxygen to hydrogen peroxide at about 300 mV lower potential than the bare glassy carbon electrode. The polymer film consisted of more than two components. Among those, only one component was active in oxygen reduction, which was formed mainly in the earlier stage of the electropolymerization. 2,3-Diaminophenazine, a cyclic dimer of o-PD, was also active in the oxygen reduction reaction, from which it was suggested that the active polymeric component has a structural unit similar to the cyclic dimer. Finally, the electropolymerization mechanism for the formation of the active and inactive components has been proposed.

• Korean Journal of Environmental Agriculture
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• v.35 no.3
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• pp.211-215
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• 2016

BACKGROUND: The commercial biopesticides containing Chenopodium ambrosioides L. extracts which have been registered as one of the ingredients of the commercial biopesticide by the organic agriculture materials, and have been widely used in Republic of Korea. However, the quantitative analysis method of the active substances for the commercial biopesticides containing C. ambrosioides L. extract has not been conducted.METHODS AND RESULTS: To analyze the quantitative analysis of ascaridole, carvacrol, and p-cymene as active substances of C. ambrosioides L. extract, hydrophilic lipophilic balance cartridge was used for solid phase extraction. The active substances were analyzed by the gas chromatography with flame ionization detector. The limit of quantitation values of ascaridole, carvacrol, and p-cymene were 10, 5, and 2 mg/L, and the recovery rates were 96.3, 84.0, and 82.5% in liquid products and 98.3, 99.1, and 97.3% in solid products, respectively. The total content of ascaridole, carvacrol, and p-cymene in the commercial biopesticides was ranged from 0.08 to 12.75%.CONCLUSION: From these results, this method was suitable for the quantitative analysis of the active substances of commercial biopesticides containing C. ambrosioides L. extract.

• Korean Chemical Engineering Research
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• v.57 no.1
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• pp.17-21
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• 2019

The redox flow battery (RFB) is a large-capacity energy storage equipment, and the vanadium redox flow cell is a typical RFB, but VRFB is expensive. Iron-chrome RFBs are economical because they use low-cost active materials, but their low performance is an urgent problem. One of the reasons for the low performance is the crossover of the active materials. In this study, the sulfonated Poly (ether ether ketone) (sPEEK) membrane, which is a hydrocarbon membrane, was used instead of the fluorine membrane to reduce the crossover of the active materials. The chromium ion permeability of the sPEEK membrane was $1.8{\times}10^{-6}cm^2/min$, which was about 1/33 of that of the Nafion membrane. Thus, it was shown that the use of the sPEEK membrane instead of the fluorine membrane could solve the high active material crossover problem. The activation energy of iron diffusion through the sPEEK membrane was 24.9 kJ/mol, which was about 66% of Nafion membrane. And that the e-PTFE support in the polymer membrane reduces the active material crossover through Iron-Chrome Redox Flow Battery (ICRFB).

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.327-330
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• 2005

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.308-312
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• 2013

Active carbons with high specific surface area and micro pore structure were prepared from the coconut shell char using the chemical activation method of NaOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to char ratio and the flow rate of gas during carbonization. The active carbons with the surface area (2,481 $m^2/g$) and mean pore size (2.32 nm) were obtained by chemical activation with NaOH. The electrochemical performances of hybrid capacitor were investigated using $LiMn_2O_4$, $LiCoO_2$ as the positive electrode and prepared active carbon as the negative electrode. The electrochemical behaviors of hybrid capacitor using organic electrolytes ($LiPF_6$, $TEABF_4$) were characterized by constant current charge/discharge, cyclic voltammetry, cycle and leakage tests. The hybrid capacitor using $LiMn_2O_4$/AC electrodes had better capacitance than other hybrid systems and was able to deliver a specific energy as high as 131 Wh/kg at a specific power of 1,448 W/kg.

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.88-89
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• 2000

The properties for self-frequency doubling (SFD) is unique phenomena for a small number of special single crystals. It is known that there are serious limitations to vary the concentration of active ions, for example high doping of active ions from 1 to 50 atomic %, in nonlinear materials. Until now, the Nd:YAl$_3$(BO$_3$)$_4$ (YAB) and Nd:(Ce,Gd)Sc$_3$(BO$_3$)$_4$ (CSB) crystals with high doping rates are well studied for the application of SFD purpose. They have much useful SFD properties, but also have big problems in crystal growth. In case of YAB crystal, it can be grown by solution melt method with very low growth rates and easy occurrence of inclusions. In case of CSB crystal, it has optically heterogeneity problems because of disarrangement of ions in huntite structure [1]. These problems make above crystals not so attractive for optical applications. Some popular nonlinear materials, such as LiNbO$_3$(LN), KTiOPO$_4$(KTP), LiB$_3$O$_{5}$ (LBO) crystals, are impossible to substitute by Rare Earth activators because of their crystallo-chemical problems of structure. When we dope active ions with the requisite concentrations for laser generation, it results in decreasing of optical quality of crystals or destroying of acentrosymmetric structure. (omitted)d)

• Journal of Electrochemical Science and Technology
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• v.2 no.4
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• pp.204-210
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• 2011

Thin film electrodes have been intensively studied for active materials and current collectors to enhance the electrochemical performance. Here, porous structures of nickel-based oxide films, consisting of nickel oxide and copper (II) oxide, which was derived from the copper substrate during the annealing process, were deposited on metallic copper foils. The half-cell tests revealed excellent capacity retention after $80^{th}$ charge/discharge cycles. Some films showed an excess of the theoretical capacity of nickel oxides, which mainly originate from partially oxidized copper substrates during annealing. These results exhibit that both a preparation method of an active materials and partially oxidized current collectors could be important roles to apply thin film electrodes.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.72-79
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• 2018

Hybrid F2HX surfactants bearing a sulfate moiety and both hydrocarbon and fluorocarbon chains were prepared by the reaction of alkyl glycidyl ethers with fluoro-alcohol, and subsequent sulfation. The fluorocarbon number in F2HX was fixed at the shortest number possible (i.e., 2), while the hydrocarbon number (X) in the second chain was varied between 2, 4, 6, and 8. Their surface-active properties and emulsion stabilities were systematically estimated as a function of the X. Among them, F2H8 exhibited the optimal surfactant performance, which was comparable to previously reported surfactants and it was successfully applied in the emulsion polymerization of vinylidene fluoride.

• Bulletin of the Korean Chemical Society
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• v.24 no.11
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• pp.1641-1648
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• 2003

New and facile synthetic routes for preparation of optically active norephedrine, norpseudoephedrine and cathinone with high optical purities via double asymmetric induction by employing asymmetric reduction of 2-N-protected amino (or azido)-1-phenylpropanone and 2-methanesulfonyloxy-1-phenylpropanone with CBS-catalyzed-borane and $^dIpc_2BCl$ as chiral reducing agents are described.