• The Korea Beekeeping Bulletin
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• s.253
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• pp.27-29
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• 2001

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.265-265
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• 1994

• 한국과학교육학회:학술대회논문집
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• 2008.01a
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• pp.128.1-128.1
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• 2008

• 치위협보
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• s.102
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• pp.1-12
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• 2005

• 한국과학교육학회:학술대회논문집
• /
• 2009.02a
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• pp.51.2-51.2
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• 2009

• 한국과학교육학회:학술대회논문집
• /
• 2009.02a
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• pp.51.1-51.1
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• 2009

• Bulletin of the Korean Chemical Society
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• v.19 no.8
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• pp.868-874
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• 1998

An equivalent retention has been experimentally observed in thermal field-flow fractionation (ThFFF) for different polymer-solvent systems. It is shown that iso-retention between two sets of polymer-solvent systems can be obtained by adjusting the temperature difference (ΔT) according to the difference in the ratio of ordinary diffusion coefficient to thermal diffusion coefficient. This method uses a compensation of field strength (ΔT) in ThFFF at a fixed condition of cold wall temperature. It is applied for the calculation of molecular weight of polymers based on a calibration run of different standards obtained at an adjusted AT. The polymer standards used in this study are polystyrene (PS), polymethylmethacrylate (PMMA), and polytetrahydrofuran (PTHF). Three carrier solvents, tetrahydrofuran (THF), methylethylketone (MEK) and ethylacetate (ETAc) were employed. Though the accuracy in the calculation of molecular weight is dependent on the difference in the slope of log λ vs. log M which is related to Mark-Houwink constant a, it shows reasonable agreement within about 6% of relative error in molecular weight calculation for the polymer-solvent systems having similar a value.

• The Korean Journal of Zoology
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• v.37 no.4
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• pp.545-553
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• 1994

척추동물의 초기 발생에 관여하는 물질로 알려져 있는 retinoic acid(RA)를 Xenopus 배(embryo)에 처리한 결과, 체절의 형성에 이상 발생이 나타났다 즉 낭배 초기에 RA에 노출된 개체의 체절은 대조군의 화살머리 모양((((() 대신 기등 모양(1111)을 형성하고 있었으며, 고농도일수록 직선에 가까운 모습을 하고 있었다. 신경배 시기에 노출된 개체의 체절은 정상적인 분절이 이루어지지 않았으며, 이들 이상 체질의 위치는 처리 시기에 따라 다르게 나타났으나 농도에는 영향을 받지 않았다. 그러나 분절 과정중 일어나는 체절 세포들의 회전은 RA에 의해 억제되지 않았다. 이와 같은 결과는 체절의 형성에 분절 이전의 세포의 행동을 주도하는 프로그램과 분절을 주도하는 프로그램이 분리되어 있음을 암시한다. 한 가지 특이한 사항은 열처리 등으로 유발된 혼란이 수 개의 체절에 국한되어 나타나는 점과는 달리 RA의 처리는 어느 지점 이 후부터 모든 체절에 혼란을 야기시킨다는 점이다. 이와 같은 연속적인 분절의 흔란 현상은 RA가 다른 저해제에 의해 영향을 받는 유전자의 활동을 조절하는 전 단계의 유전자에 영향을 주기 때문인 것으로 사료된다. 또한 신경배 시기에 RA에 노출된 배의 a-cardiac actin은 정상적으로 발현되는데 비해 낭배 초기에 RA에 노출된 배는 감소된 양의 a-cardiac actin myNA의 축적을 보였다. 그러나 EFI-u은 RA의 처리 시기와는 무관하게 정상적으로 발현되었다.

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1159-1164
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• 1999

The study investigated the effect of carrier composition (ionic strength and pH) on the retention of various proteins in flow field-flow fractionation (Flow FFF) as well as the conformational change of Bovine Serum Albumin (BSA) with urea concentration, storage time and temperature. The study found that the retention of protein in Flow FFF increased with the ionic strength of the carrier liquid. Most proteins were well solubilized at pH = 7-8. The hydrodynamic diameters obtained from Flow FFF retention data agree well with theoretical values. The retention increased and the peak shape became distorted at extreme pH conditions of the carrier solution. The selected carrier composition for comparison between the literature value of proteins was 0.05 M tris buffer solution with a pH of 8. Storing BSA at 4 ±2℃ over a period of three months resulted in slow dimerization. Also, in case of the storage of BSA at 37 ±5℃ for one week, the retention of both BSA monomer and dimer increased with the urea concentration. Finally, the structural composition of specific enzymes: malonyl-CoA decarboxylase (MCDC) and malonyl-CoA synthesis (MCS) was determined by using Flow FFF at specific carrier solutions. The molecular weight of the natural MCDC was determined to be 208 kDa, which means it is a homotetramer, while that of the MCS was determined to be 47 kDa, which means it is a monomer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6B
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• pp.616-624
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• 2002

In satellite communication, which use the satellite, the protection of TT&C channel which controls the position, performance, and operation is required. In this thesis, we analyzed the weakness of authentication algorithm which is used for protection of TT&C generation and operation. Also, we proposed the authentication algorithm which complements key recovery attack structurely without increasing additional computational amount and verified its performance. The proposed authentication algorithm can satisfy Rivest's recommendation by increasing the computational complexity from $2^{55}$ operations to $2^{111}$ operations. In addition, it can be applied to the existing satellite system because the length of TT&C data and message authentication codes used for the input of authentication algorithm are unchanged.