• Bulletin of the Korean Chemical Society
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• 제28권5호
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• pp.847-850
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• 2007

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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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.

• 한국인쇄학회지
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• 제7권1호
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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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• 제8권3호
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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.

• 폴리머
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• 제37권2호
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• pp.135-140
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• 2013

Poly(methyl acrylate)-poly(acrylonitrile) 공중합체의 응력완화 실험은 용매기를 부착한 인장 시험기를 사용하여 여러 온도의 공기 중, 증류수, pH 3, 7, 11 용액에서 실행하였다. Ree-Eyring and Maxwell 모델로부터 얻은 완화스펙트럼 식에 실험적인 응력완화 곡선을 대입하여 poly(methyl acrylate)-poly(acrylonitrile) 공중합체의 완화스펙트럼을 얻었다. 완화스펙트럼의 계산은 Laplace 변환법을 사용한 컴퓨터 프로그램을 이용하였다. 이들 시료의 완화스펙트럼은 유동단위의 분자량과 자체확산 분포와 밀접한 관계가 있음을 알 수 있었다.

• Elastomers and Composites
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• 제44권4호
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• pp.397-400
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• 2009

오존은 상온에서 폴리머 이중 결합의 산화작용을 활발하게 하여 표면 갈라짐을 유발시킨다. 왁스는 고무 표면으로 이동하여 물리적 방어막을 형성하여 오존의 작용을 방지한다. 비보강 NR, SBR, BR 가황물을 상온에서 6개월간 노화 시켜 노화 전후의 왁스의 분자량 분포 변화를 조사하였다. 상온 조건에서 고무 가황물에 있는 왁스의 이동과 증발 거동은 노화방지제로서의 왁스의 역할과 고무 제품의 외관 오염을 이해하는데 도움을 준다. NR 시험편에서 알칸의 상대 세기 분포는 노화 후 고분자량쪽으로 이동하였으나 SBR 시험편의 경우에는 노화 전후의 분자량 분포 모양에는 큰 차이가 없었다.

• KSBB Journal
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• 제13권1호
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• pp.114-118
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• 1998

실크의 피브로인 단백짐의 가수분해에 의한 실크 펠타이드의 제조를 위하여 설크의 가용화 조건이 분자량 분포에 미치는 영 향을 고찰하였다 염 화칼숨, ethylenediamine 및 황산에 의해 가용화된 실크의 평균 분자량은 각각 41600, 3308과 1268 dalton 으로서 염화칼숨을 제외한 나머지 두 가용화 방법에서 평균 분 자량이 수천 dalton인 실크 용액을 얻을 수 있었으며 분산계수 는 3-4의 범위뜰 보였다. 가용화 및 분말화한 후 6시간 동안 단백질 분해효소 처리에 의하여 600-1200 dalton의 중량평균 분 자량을 갖는 살크 접타이드틀 얻을 수 있었다. 24시간 염산에 의한 산분해 처리에 의해 얻은 실크 웹타이드의 평균 분자량은 145 dalton으로 80%의 높은 유리 아미노산 함량을 나타내었다. 여러가지 가용화 방법 및 가수분해 방법 중 낮은 농도의 황산용 액으로 우선 실크를 가용화한 후 중화 및 효소처리에 의해 웹타 이드로 가수분해하는 방법이 과도한 아미노산의 유리를 억제하 면서 분자량의 조절도 용이할 것으로 판단되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권12호
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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.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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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.

• 한국잠사곤충학회지
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• 제42권1호
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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.