• Proceedings of the Korean Society of Crop Science Conference
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• 한국작물학회 2023년도 춘계학술대회
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• pp.180-180
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• 2023

• Korean Journal of Fisheries and Aquatic Sciences
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• 제19권3호
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• pp.227-233
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• 1986

The compositions and seasonal variations of free sugars and non-volatile organic acids of brown algae, such as Ecklonia cava, Sargassum ringgoldianum and Myagropsis myagroides were investigated by gas chromatography. Four kinds of free sugars, such as xylose, glucose, galactose and floridoside were identified. The most abundant one was floridoside marking 118.7 mg/100 g, 90.9 mg/100 g and 70.0 mg/100 g in Ecklonia cava, Sargassum ringgoldianum and Myagropsis myagroides, respectively. There were not distinguishable seasonal variations in the contents of free sugars in all the samples. In the case of organic acids, nine kinds were identified in Ecklenia cava and major ones were succinic, citric, malic, fumaric, oxalic and lactic acid, of which succinic acid was the most abundant one marking $30.6\%$ of total organic acids. In Sargassum ringgoldianum and Myagropsis myagroides, eight kinds were identified, which major ones were succinic, citric and malic acid in both samples, and they marked $68.4\%$ and $61.1\%$ of total organic acids in Sargassum ringgoldianum and Myagropsis myagroides, respectively. There were not distinct changes in the content of total organic acids according to seasons in all the samples examined. The contents of total organic acics in Ecklonia cava was a little more than Sargassnm ringgoldianum and Myagropsis myagroides.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• 제44권3호
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• pp.41-48
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• 2012

Materials used for the inks in the printing industry is an important material following the paper. The composition of the ink is pigment and organic solvents. However, Ink is used in a variety of chemicals, they are classified as non-green. Therefore, rosin-modified phenolics manufactured by the reaction of phenol and formaldehyde can take the place of eco-phenol free resin and by experiment density, gloss, trapping, contrast and dot gain of printing has been studied as printability. The result of study can support that the properties of printing using eco-phenol free resin such as density, gloss, contrast and trapping is similar to existing ink. In the part of dot gain, the result is excellent. So we were thought to be able to improve some characteristics such as dispersion of black ink, that will be possible for the field applicability.

• Progress in Superconductivity and Cryogenics
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• 제7권3호
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• pp.5-8
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• 2005

Superconducting YBCO films were successfully fabricated by MOD process using F-free Cu precursor solution. In this study. a chemically modified precursor solution for MOD Processing was synthesized using metal-organic salts and F-free Cu precursor. It was shown that crack-free and uniform precursor films were formed after calcination in humidified oxygen atmosphere. Less than 3 hours are required to finish the calcination process. XRD measurement shows that $BaF_2,\;CuO,\;Y_2O_3$ are major constituent of precursor films. Furthermore. YBCO films without any secondary phases were successfully fabricated after annealing in wet $Ar/O_2$ prepared on a $LaA1O_3$ single crystal substrate $(10mm{\times}10mm)$ gives transport Ic of 10A at 77K. This chemical modification approach is a possible candidate for improving MOD-processing of YBCO coated conductor.

• Advances in materials Research
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• 제3권2호
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• pp.117-128
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• 2014

Processable conducting polyaniline derivative with free amine functional groups was successfully synthesized from the monomer o-phenylenediamine in aqueous hydrochloric acid medium using ammonium persulfate as an oxidative initiator. The synthesized poly(o-phenylenediamine) (PoPD) in critical condition was found to be completely soluble in common organic solvents like dimethyl sulfoxide, N,N-dimethyl formamide etc. From the intrinsic viscosity measurement, the optimum condition for the polymerization was established. The polymer was characterized by ultraviolet visible spectroscopy, Fourier transform infrared spectroscopy, proton magnetic resonance spectroscopy ($^1HNMR$) and thermogravimetric (TGA) analyses. The weight average molecular weights of the synthesized polymers were determined by the dynamic light scattering (DLS) method. From the spectroscopic analysis the structure was found to resemble that of polyaniline derivative with free amine functional groups attached to ortho/meta position in the phenyl ring. However, very little ladder unit was also present with in the polymer chain. The moderate thermal stability of the synthesized polymer could be found from the TGA analysis. The average DC conductivity of $2.8{\times}10^{-4}S/cm$ was observed for the synthesized polymer pellet after doping with hydrochloric acid.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2243-2248
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• 2011

Carbon-based solid acid catalyst was found to be highly efficient, eco-friendly and recyclable heterogeneous catalyst for the multicomponent reaction of dimedone, aromatic aldehydes, and a nitrogen source (ammonium acetate or aromatic amines) under solvent-free conditions, giving rise to 1,8-dioxodecahydroacridines in high yields. The present methodology offers several advantages, such as a simple procedure with an easy work-up, short reaction times, high yields, and the absence of any volatile and hazardous organic solvents.

• Journal of the Korean Chemical Society
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• 제55권6호
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• pp.936-939
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• 2011

Thiamine hydrochloride (VB1) has been used as an acid catalyst in organic synthesis. One pot three component Biginelli condensation of dimedone, urea/thiourea and substituted aromatic aldehydes catalyzed by 10 mol % of thiamine hydrochloride (VB1) in solvent free condition under microwave irradiation in good to excellent yields has been investigated. Utilization of microwave irradiation, simple reaction conditions, short reaction time, ease of product isolation, and purification makes this manipulation very interesting from an economic and environmental perspective.

• Journal of Life Science
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• 제10권2호
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• pp.131-139
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• 2000

Lecithin-free egg yolk protein (EYP), the by-product of lecithin extraction from egg yolk, which is denatured with an organic solvent, would normally be discarded. In this study, the denatured protein was renatured with alkali, and hydrolyzed with Alcalase in order to utilize by-product. The hydrolysate was separated through a series of ultrafiltration membranes with molecular weight cut-off (MWOO) of 10, 5 and 1 kDa, and the antioxidative activities of the hydrolysates was investigated. The 5K hydrolysate, permeate from 5 kDa membrane, showed stronger antioxidative activity than 10 K and 1 K hydrolysate which were permeated from 10 kDa and 1 kDa membrane, in a linoleic acid autoxidation system. In addition, the optimum concentration of antioxidative activity for 5 K hydrolysate was 1%, and the activity was about 37% higher as compared with α-tocopherol. The synergistic effect was also increased by using the hydrolysates with α-tocopherol.

• Journal of Korean Vacuum Science & Technology
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• 제4권3호
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• pp.63-67
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• 2000

We have studied the photoluminescence properties of undoped epitaxial layers of GaN on sapphire substrate grown by horizontal low pressure metal organic chemical vapor deposition method in the temperature range of 9-300 K. At 9 K the spectra are dominated by the well resolved interband free excitons A and B as well as bound excitons. Temperature dependence of free exciton transitions was studied and Varshni's coefficients for the temperature variation of bandgap were determined.

• Journal of Plant Biology
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• 제29권3호
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• pp.157-165
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• 1986

The onset of photophosphorylation at the various stages of greening showed different patterns with varying concentrations of Pi. With further greening, ATP formation occurred at the lower concentration of Pi (48 hrs; 0.05 mM). At early stages of greening, more Pi was required for photophosphorylation (6 hrs; 5.0 mM). The addition of cell-free extracts of etiolated barley seedlings resulted in the competitive inhibition of photophophorylation. The apparent inhibition by cell-free extracts were gradually decreased during greening of etiolated barley seedlings. We found that the inhibitors of photophosphorylation in cell-free extracts were some organic phosphates and most of them was P-choline. P-choline inhibited photophosphorylation competitively with Pi and its content was decreased considerably in greening. It is likely that P-choline partly delay the photophorylation in early stages of greening.