• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.264-269
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• 1993

Molecular structural properties of legume starches were investigated. In intrinsic viscosity and degree of Polymerization of amylose and amylopectins, cow pea and mung bean were high, but kidney bean was low. Low molecular weight fractions for kidney bean starch were much eluted by gel chromatography. In the elution profiles of their amylose by Sepharose 2B-CL, molecular weight of kidney bean amylose was smaller than that of other amylose Molecular weights of cow pea and mung bean amyloses were large, but that of kidney bean amylose was small and red bean amylose was medium. The elution profiles by Sephadex G-50 after debranching amylopectins with pullulanase showed similar patterns.

• Polymer(Korea)
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• v.39 no.1
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• pp.165-168
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• 2015

Thermoresponsive polymers were successfully synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide and alkynes (click chemistry). Poly(2-hydroxyethyl methacrylate) (PHEMA) was synthesized by ATRP, followed by introduction of alkyne groups using pentynoic acid, leading to HEMA-alkyne. Homopolymers having secondary amine groups, tertiary amines with hydroxyethyl and hydroxypropyl groups were synthesized by adding 2-azido-N-ethyl-ethanamine, 2-[(2-azidoethyl)amino]ethanol, and 2-[(2-azidoethyl)amino]propanol, respectively, to the PHEMA-alkyne backbone using click chemistry. Molecular weight (MW), molecular weight distribution (MWD), and click reaction efficiency were determined by gel permeation chromatography (GPC) and $^1H$ NMR spectroscopy. The transmission spectra of the 1.0 wt% aqueous solutions of the resulting polymers at 650 nm were measured as a function of temperature. Results showed that the lower critical solution temperature (LCST) could be easily controlled by the length of the hydroxyalkyl groups.

• Polymer(Korea)
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• v.32 no.6
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• pp.566-572
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• 2008

Polyethylene has been prepared via metallocene catalysts [(TMDS)$Cp_2$]$ZrCl_2$, 1, and [$(n-Bu)_2Cp_2$]$ZrCl_2$, 2, in the presence of hydrogen as a chain transfer reagent. Increase of hydrogen flow to the polymerization reactor resulted in the drop of catalytic activity, reduction of molecular weight of polyethylene, getting narrow of molecular weight distribution of polyethylene, and melting point of the polyethylene wax. It should be noticed that it was possible to control molecular weight down to 1500 and melting temperature to 60 $^\circ$C of polyethylene wax using the catalyst 1 that has been developed by authors as well as the catalyst 2 from Exxon.

• Proceedings of the Korean Aquaculture Society Conference
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• 2004.05a
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• pp.117-118
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• 2004

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.04a
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• pp.48-56
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• 2001

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.53.4-54
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• 2015

분자운의 광대역 분포는 작은 영역에서는 볼 수 없는 독특한 모습을 보여준다. 본 연구는 2010년도 TRAO 관측으로 얻는 외은하면의 $4.3^{\circ}{\times}2^{\circ}$의 광대역 데이터를 사용해서 광대역 분자운 분포의 특성을 분석했다. 광대역 분자운들은 형태학적 특징에 의거해서 네 종류로 분류되었다: chain, twisted filament, speckle, cluster suspect 이들의 특징을 간략히 소개하고 광대역 분자운들을 보는 새 관점으로 분자운 충돌 이론을 소개한다. 그와 함께 광대역 연구의 대표적인 예로 두 전파원을 소개한다. 첫째는 CTB109 (3C 434.1) 근처 분자운이며, 길다란 CO filament가 포함된다. 둘째는 "집게벌레(S157 ab 포함)"로서 강한 별 탄생을 보여주는 특이한 영역으로서 강한 CO emission이 두 개 twisted filament 구조를 보여준다. 연구에는 DRAO HI, IRAS 적외선 자료, DRAO Radio continuum data를 사용했고, CO 자료를 통해서 분자운의 질량과 밀도, 온도 등의 기본 물리량을 계산했다.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.3
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• pp.253-255
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• 2001

기능성고분자재료 중의 하나인 7원환 고리아세탈 화합물인 1,3-dioxepan-2-one(1)을 합성하고 고온조건 하에서 중합반응을 조사한 결과 선택적인 개환중합이 일어났다. 그러나 낮은 농도에서 작은 분자량을 가지는 고분자가 얻어졌으며 넓은 분자량 분포와 낮은 수율이 얻어지며 이것은 중압반응 도중에 분자 내에서 상호반응을 일으킴을 보여준다.

• Elastomers and Composites
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• v.35 no.4
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• pp.261-271
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• 2000

Physical properties of NR vulcanizates cured by both sulfur and resole were studied. Cure characteristics of the compounds were also investigated. Two types of resoles with different molecular weight distributions were employed. The scorch time of the NR compound containing the resole with a low molecular weight distribution was shorter than that of the compound containing the resole with a high one. Crosslink densities of the NR vulcanizates with a high resole content after the thermal aging at $95^{\circ}C$ decreased, while that of the vulcanizate without resole after the thermal aging at $95^{\circ}C$ increased. Though crosslink densities of the NR vulcanizates with a high resole content decreased with increasing the aging time, the moduli increased while the tensile strength and tear strength decreased.

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.486-491
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• 1989

The textural properties of cooked rice and the molecular weight distribution of amyloses of three rice cultivars different in cooking quality were investigated by the method involving rheometry and gel chromatography he tested rice cultivals were Chunmabyeo (short grain), Yongmunbyeo (medium grain) and Mahatma (long grain) The cooked rice prepared with Mahatma was higher in hardness and lower in adhesiveness than those prepared with the other two cultivars. The molecular wright distribution of amylose from Mahatma was found to be higher than those from the other cultivars.

• Environmental Mutagens and Carcinogens
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• v.9 no.2
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• pp.63-72
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• 1989

본 연구는 N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) 를 처리한 CHO-K1세포에서 DNA 복제억제와 그 회복과정의 분자론적 기작을 규명할 목적으로 방사선 이중표지에 의한 DNA합성율의 측정, 알카리 자당농도구배 초원심분리법에 의한 DNA 분자량과 후복제 회복율을 측정하여 다음과 같은 결과를 얻었다. DNA 합성율은 2nM 이하의 낮은 농도의 MNNG 처리군에서는 급격히 감소하였으나, 5nM 이상의 농도에서는 그 감소양상이 둔화되었다. 억제되었던 DNA 합성율은 시간경과에 따라 회복되어 처리 후 4시간 째에는 대조군 수준 또는 그 이상으로 회복되었다. MNNG 처리 후 DNA 분자 크기의 분포와 새로 합성된 DNA 분자의 생장양상을 알카리 자당농도구배 초원심분리법으로 조사한 결과 MNNG 처리 후 시간 경과에 따라 새로합성된 DNA 분자들의 크기분포는 1*107 달톤 이하의 DNA 분자들의 합성양이 특이하게 증가하였다가 감소함을 보였다.