• Bulletin of the Korean Chemical Society
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• v.28 no.5
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• pp.847-850
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• 2007

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.621-625
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• 2003

In order to investigate the properties of aqueous fibroin solution, the molecular weight distribution of silk fibroin was determined by gel filtration chromatography. The molecular weights spreaded from 200 kDa to less than 20 kDa. The distribution of molecular weight was significantly affected when the pH of solubilization solution is less than 1. Distributions of fibroin solution stored at various condition were also investigated.

• Journal of the Korean Graphic Arts Communication Society
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• v.7 no.1
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• pp.65-72
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• 1989

Modified phenolics can have a retarding effect on the gelation of wood oil. Modified phenolic resins can be used in media for paint, varnishes, primers, overprinting varnishes, litho, letterpress and rotogravure inks. Varnishes based on rosin phenolic are faster drying, have better durability, are harder and glosser, and have greater resistance to water than ones based on ester gums. These physical properties is concerned with molecular weight distribution of rosin modified phenol resin. This paper was studied about molecular weight distribution of rosin phenolics which were prepared between $130~250^{\circ}C$. The results were as follows: 1) Average molecular weights inereased with increasing reaction temperature. 2) $M_w/M_n$ were from 3.43 to 46.44 with increasing reaction temperature and so the molecular weight distributions were changed from random distribution to broad distribution. 3) The relation ship between intrinsic viscosity and weight average molecular weight was follows: $[{\;}{\;}]={\;}1{\times}{\;}10^{-6}M_w,{\;}M_w=M_w$ 4) Esterification reaction between the acid group of rosin and polyol was started about $230^{\circ}C$$.

• Fisheries and Aquatic Sciences
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• v.8 no.3
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• pp.113-117
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• 2005

To prepare oligouronic acids from high-molecular-weight alginates, sea tangle Laminaria japonicus alginates were hydrolyzed at $80^{\circ}C$ for various hydrolysis times (HT). The effects of hydrolysis time on the distribution ratios (DR) of the molecular weights (MW) of the hydrolyzed alginates were in-vestigated. As HT increased, the DR of the alginates with MW>500 kDa decreased ex-ponentially, while those with MW=50-100 kDa or MW<50 kDa increased exponentially. For MW=300-500 kDa, DR increased exponentially until HT reached 60 min, and then decreased exponentially. Similarly, for MW=100-300 kDa, DR increased exponentially until HT reached 90 min, and then decreased.

• Polymer(Korea)
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• v.37 no.2
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• pp.135-140
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• 2013

The stress relaxation of poly(methyl acrylate)-poly(acrylonitrile) copolymer samples was carried out in air, distilled water, pH 3, 7 and 11 solutions at various temperatures using a tensile tester equipped with a solvent chamber. The relaxation spectra of poly(methyl acrylate)-poly(acrylonitrile) copolymers were obtained by applying the experimental stress relaxation curves to the equation of relaxation spectrum derived from the Ree-Eyring and Maxwell model. The determination of relaxation spectra was performed from computer calculation using a Laplace transform method. It was observed that the relaxation spectra of these samples are directly related to the distribution of molecular weights and self-diffusions of flow segments.

• Elastomers and Composites
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• v.44 no.4
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• pp.397-400
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• 2009

Ozone caused the crack on the surface of a rubber article by oxidation of double bond at room temperature. Wax migrates to the surface of a rubber article and makes a physical barrier to prevent process of ozonation. We investigated change of molecular weight distribution of waxes in unfilled NR, SBR, and BR vulcanizates before and after aging at room temperature for 6 months. Migration and evaporation behaviors of wax in a rubber article at ambient conditions help understand a role of wax as an antidegradant and appearance contamination of a rubber article. The relative intensity distribution of n-alkanes of the NR specimen after the aging was shifted to higher molecular weight compared with the relative intensity distribution before the aging, while those of the SBR specimen before and after the aging did not show a big difference.

• KSBB Journal
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• v.13 no.1
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• pp.114-118
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• 1998

The effects of fibron solubilization conditions on molecular weight distribution of enzymatically-hydrolyzed silk peptides were investigated. The weight-averaged molecular weights of silk proteins prepared by solubilization with calcium chloride, ethylenediamine and sulfuric acid were 41600, 3308, and 1268 dalton, respectively. Silk peptides in the average molecular weight range of 600-1200 dalton were obtained by protease treatment from solubilized silk fibroin. After the acid hydrolysis of silk protein using hydrochloric acid for 24 hr, silk protein was hydrolyzed to peptides whose average molecular weight and free amino acid content were 145 dalton and 80%, respectively. It was possible to control molecular weight distribution of silk peptides by the combination of solubilization and hydrolysis methods. Among the various treatment methods, acid solubilization followed by protease treatment had an advantage of molecular weight control for the peptide production.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.12
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• pp.1666-1673
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• 2011

The presence of sialoglycoproteins (SGPs) in the membranes from goat (Capra aegagrus hircus), buffalo (Bubalus bubalis bubalis) and pig (Sus scrofa domestica) erythrocytes was investigated by partial purification with a chloroform-methanol extraction method followed by Sodium dodecyl sulphate - Polyacrylamide gel electrophoresis in comparison to human (Homo sapiens) erythrocytes. The results show that mammalian erythrocytes possess clear differences in the SGPs numbers and molecular weights although all animals studied in this experiment are from the same class i.e. mammalia. The SGPs number in human, goat, buffalo and pig are four (PAS-1 to PAS-4), ten (PAS-GI to PAS-GX), seven (PAS-BI to PAS-BVII) and four (PAS-PI to PAS-IV) respectively as indicated by staining the polyacrylamide gel with sialoglycoprotein-specific Periodic acid-Schiff's (PAS) stain. The new SGPs could be observed only after the partial purification of membrane fractions named as PAS-HI with molecular weight (Mr) 190 kDa and PAS-HII 150 kDa in human, PAS-BIA in buffalo and PAS-PIA and PAS-PIVA in pig. The gels were also stained with Coomassie brilliant blue (CBB) and Silver stain to check the contamination of other membrane proteins in the purified fractions. The quantitative distribution of SGPs was also determined by densitometry. Present study indicates that there are some basic differences in mammalian erythrocyte membrane SGPs, especially with respect to their number and molecular weights indicating major structural variations.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.324-324
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• 2006

In copolymerization of methyl acrylate (MA) and methyl methacrylate (MMA) with various ratios of MA to MMA and $[CuCl]/[PMDETA]/[PVAc-CCl_{3}]$ catalyst system in bulk at $80^{\circ}C$ via ATRP, several terpolymer with different copolymer composition, were synthesized. The atom transfer radical copolymerization of MA and MMA with macroinitiator, is very sensitive to molecular weight and its distribution. In this work it was possible to calculate the molecular weight of the terpolymers and show that it is close to the experimentally determined number average molecular weight from GPC.

• Journal of Sericultural and Entomological Science
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• v.42 no.1
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• pp.48-57
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• 2000

This study was undertaken to figure out the effects of hydrolysis conditions on the solubility of insoluble sericin, molecular weight distribution and thermal characteristics of hydrolysates in enzymatic hydrolysis by Alcalase 2.5L. It was indicated that the optimum treatment temperature and pH for the insoluble sericin were 50$\^{C}$ and 11, respectively. When the insoluble sericin was hydrolyzed with a various treatment conditions, the solubility of all hydrolysates were represented above 85% at given conditions. As the enzyme concentration increased, the solubility increased roughly, but the solubility increasement ratio was less above 2% enzyme concentration. As the treatment time increased, the solubility was also increased. It was showed in the molecular weight distribution of hydrolysates treated various enzyme concentrations and treatment times that when enzyme concentrations were 0.5, 2, 3%, the peaks of the distribution curve were shifted to left side which meant low molecular weight and was distributed much quantity with shifted to be left side, but treatment time was 6 hr. the peak was shifted to right side. When enzyme concentration was 5% and treatment time was below 2 hr., the peaks were shifted to right side, but treatment time was above 4hr. the peak was shifted to left side. The number-average molecular weights were distributed from 300 to 800 and those were decreased when treatment time was up to 4 hr., but increased a little when treatment time was 6hr. It was showed in the DSC curves of hydrolysates treated with treatment time of 0.5, 1, 2, 4, 6 hr. fixed 1% o.w.s enzyme concentration and control that the endothermic peak was observed near at 200$\^{C}$. The denaturation peak of the hydrolysates depending on treatment times had a tendency to shift to higher temperature. But, when the treatment time was 6 hr., the peak was shifted to lower temperature comparing another hydrolysates.