• Journal of the Korea Concrete Institute
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• v.18 no.4 s.94
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• pp.489-496
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• 2006

Graft copolymerized polycarboxylate(PC)-type superplasticizers which have carboxylic acid with $\pi$ bond among the molecular structure and polyethyleneglycol methyl ether methacrylate(PMEM) were synthesized by free radical reaction. To investigate their chemical structures and molecular weights, PCs were analyzed by FT-IR(fourier transform spectrometer), C-NMR(nuclear magnetic resonance spectrometer) and GPC(gel permeation chromatograpy). When types of carboxylic acids(methacrylic acid, acrylic acid, maleic anhydride, and itaconic acid) and molar ratios of carboxylic acid/PMEM) were varied, adsorptive and fluid characteristics in cement paste were discussed. As the molar ratio of carboxylic acid/PMEM) was higher, amount adsorbed on the cement particles and the fluidity of cement paste by mini-slump spread testing method were increased. When main chain of PC was methacrylic acid, a larger amount was adsorbed on the cement particles. PCs with acrylic acid as main chain showed higher dispersing power. However, it was confirmed that PCs with dicarboxylic acids(maleic anhydride, itaconic acid) didn't have good adsorption and dispersibility.

• Journal of the Korean Chemical Society
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• v.20 no.1
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• pp.43-47
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• 1976

The determination of oxalic acid is carried out with Zr(IV)-XO complex by spectrophotometry. The Mechanism of this method in 1∼4N HCl solution is shown below (XO = xylenol orange); Zr(IV)+XO=Zr(IV)-XO+ excess XO, Zr(IV) - XO + oxalate = Zr(IV)-oxalate + XO When oxalic acid is added to Zr(IV)-XO complex(red color), the absorbance of Zr(IV) - XO complex is decreased in proportional to the amount of oxalic acid. The malic, malonic, maleic, fumaric, succinic, folic and glutamic acid did not interfere even if they are present in hundred times of oxalic acid. If they are present in the same amount as oxalic acid, citric and tartaric acid did not interfere but they are interfere when they are present in much more than that of oxalic acid.

• Journal of Nutrition and Health
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• v.11 no.3
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• pp.21-24
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• 1978

In order to estimate the chemical composition of Raspberry (IR Crataegifalius), the free amino acids were analyzed by amino acid autoanalyzer, and organic acids contents were determined by gas chromatography and the free sugars were detected by paper chromatography. The results obtained were as follows: 1) The free amino acids found in Raspberry were 18 kinds of them, especially, all essential amino acids were showed, and lysine was abundant among them, consequently it was found that the composition of amino acids in Raspberry is more superior than those of the other fruits. 2) The organic acids in Raspberry were found citric acid, tartaric acid, malic acid and fumaric acid. It was found that the quantity of the organic acids was less than those of other common fruits. 3) Sugar such as glucose, fructose, maltose and mannose were detected by paper chromatography.

• Korean Journal of Materials Research
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• v.28 no.2
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• pp.82-88
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• 2018

Stable slurries of YSZ in aqueous suspension with added polymer dispersants, namely, poly-methacrylic acid ammonium salt (PMMA), poly-acrylic acid (PAA) and poly-acrylic-co-maleic acid (PAMA), were mixed with the monomolecular dispersants citric acid and oxalic acid. The dispersion properties of the suspension were investigated using PSA, viscosity, sedimentation, and FT-IR. The polymer dispersants and monomolecular dispersants were attached to the YSZ surface by the carboxylic group, as shown by the FTIR results. A stabilized aqueous suspension was obtained when the polymer dispersant and citric acid were mixed and compared to the use of citric acid alone as a dispersant agent. When the polymer dispersant and citric acid were mixed and milled through attrition milling, there was a smaller particle size compared to when the polymer dispersant alone was used as a dispersant agent. This study determined that the particle size of the mixed dispersant was affected by the properties of the monomolecular dispersant and that the stability of the suspension was affected by the polymer dispersant. However, when slurries of YSZ were mixed with oxalic acid, the particle bridging behavior was the result of the high degree of viscosity and the small sedimentation height.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.450-455
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• 1999

Unsaturated diol (UD) was prepared from the esterification of maleic anhydride with diethylene glycol (DEG). Unsaturated polyesters modified with rosin (UPMR) or with rosin maleic anhydride adduct (RMA) from 2-hydroxyethylmethacrylate (HEMA) and rosin (UPMRH) were prepared by the reaction of UD with RMA or RMA-HEMA. After crosslinking of UPMR and UPMRH with styrene and methylmethacrylate (MMA), respectively, solvent resistance, tensile strength, and adhesion property of the resins were measured. UPMR crosslinked with styrene or MMA shows an excellent resistance to water and acid. Solvents resistance and tensile strength of UPMR using styrene as crosslinking agent were increased compared with those of UPMR using MMA as crosslinking agent. UPMRH showed better solvents resistance and tensile strength than UPMR. Adhesion strengths of UPMR crosslinked with styrene and MMA were 1.61 and 3.02 MPa, and those of UPMRH were 2.32 and 3.89 MPa, respectively.

• Journal of the Korean Chemical Society
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• v.47 no.3
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• pp.237-240
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• 2003

A synthetic method for the title compounds (2a-o) was carried out. The title compounds (2a-o)were prepared by the condensation of various thioureas and maleic anhydride. Anti-inflammatory activities in vivo were evaluated and compared with standard drug diclofenac sodium. Some compounds showed moderate activity. The structures of all the new compounds were established on the basis of $^1H$ NMR and IR spectral data.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.43-48
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• 2010

Polyamide derived from azo compound of o-amino phenol coupled with acetyl acetone, maleic anhydride acid and p-phenylene diamine were prepared. The prepared polyamide (PA) was refluxed with metal salts of transition metal ions include, $Co^{+2},\;Cr^{+2},\;Ni^{+2},\;Cu^{+2},\;Zn^{+2},\;Cd^{+2}$ and $Fe^{+3}$ in dimethyl formamide (DMF) in different molar ratios. These complexes were characterized and identified by elemental and thermal analysis, IR, 1H NMR spectra. The data showed that PA ligand coordinates with metal ions in abidentate manner through donating N=N and O-H groups. The metal ions are surrounded by coordinated water molecules and anions to establish the geometrical structure of the complexes. The thermal analysis degradation at different temperatures explained the weight loss of hydrated water and the decompositions of complexes until a constant weight loss of metal oxides is obtained.

• Magazine of the Korea Concrete Institute
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• v.7 no.2
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• pp.175-182
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• 1995

Styrene-Maleic anhydride copolymer (SMA) was prepared by the radical copolmerization of styrene and maleic anhydride using ${\alpha}-{\alpha}'$ azobis(isobutyronitrile) as an initiatrr. SMA was further reacted with m-amino phenol to obtain aminophenol-substituted SMR (mSMA). Sulfonated SMA and mSMA were also prepared by the reaction of copolymers with sulfuric acid The copolyniers were characterized by infrared spectroscopy. It was found from the results of elemental analysis that the substitution degree of aminophenol in the mSMR is 44% and the degree is lowered to 35% after sulfonation. The percentage of copolymers adsorbed on the surface of cement particles was increased with a decrease of added copolymers. While, the arnourit of sulfonated SMA absorbed on the surface of cement particles was larger than that of the sulfonated mSMA The copolymers synthesized in this study are probably expected as a high range water reducer for coiicxte.

• Korean Journal of Medicinal Crop Science
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• v.20 no.5
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• pp.315-319
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• 2012

This study was conducted to select plant growth regulators effective at ginseng berry set inhibition to help root growth in Korean ginseng (Panax ginseng C. A. Meyer). PGRs (ethephon, gibberellic acid, maleic hydrazide, coumarin) were applied to field grown 5-year-old Korean ginseng between one and two times, before and during bloom in 2009, 2010. The number of treatment was more effective in ginseng berry set inhibition when used two times compared with one time in GA 1,000 ppm, MH (5,000, 10,000 ppm), coumarin (5,000, 10,000 ppm) treatment. According to treatment period of plant growth regulator, ginseng berry set inhibition rate from 20days before flowering date to 5days after blooming was the highest in MH 5000 ppm showing 99.9% and the lowest in GA 100 ppm showing 32.8%. The spray treatments of Ethephon (50, 150 ppm) and MH (5,000, 10,000 ppm) from 20 days before the flowering bloom up to 5 days before, and coumarin (5,000, 10,000 ppm) from 20 days to 6 days and before blooming that induced the inhibitory effect more than 90% after 12 weeks. Considering ginseng berry set inhibition characteristics and treatment period ethephon and coumarin was important about applied period but, MH treatment appeared to effective ginseng berry set inhibition regardless of treatment period.

• Magazine of the Korea Concrete Institute
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• v.8 no.4
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• pp.161-169
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• 1996

Styrene-maleic anhydride copolymers with different composition (1:1SMA. 5:1SMA) were synthesized and further reacted with sulfuric acid to obtain water soluble copolymers (1:1SSMA, 5:1SSM.4). In the flow experiments of cement mortar mixed with copolymers, 5:1SSMA showed higher fluidity than 1:1SSMA. The cement mortar mixed with 1% 5:1SSMA maintained 95% of original flow after 60 min. On the other hand, the compressive strength of the hardened cement mortars containing 0.5% copolymers after 28 days curing was also examined. The compressive strength of hardened cement mortar containing 5:1SSMA was increased up to 41% compared to the plain while 1:1SSMA was increased up to 29%. As the results, the 5:1SSMA used in this study are greatly expected as a new high range water reducers for the concrete.