• Electrical & Electronic Materials
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• v.7 no.1
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• pp.32-41
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• 1994

In this study, the TSC spectroscopy has been applied to investigate the influence of structural change due to a process of curing reaction on the electrical properties of epoxy composites cured with acid-anhydride. Five TSC peaks appeared in -160-250[.deg.C]: in the low temperature region below glass transition temperature(T$\_$g/), three relaxation mode peaks due to action of side chains, substitution group or terminal groups have been observed, a peak associated with T$\_$g/, appeared in 110[.deg. C] and p peak due to ionic space charges located in 150[.deg.C]. Each peak was separated into elementary peaks by the partial polarization procedure, and the distribution of activation energy and relaxation time were analized to clearify the origin of each peak. Also, overaboundantly added hardener separated a .betha. peak near 10[.deg. C] into two peaks of .betha.$\_$1/(10.deg. C) and .betha.$\_$2/(20.deg. C) according to increasement of forming field, and the separated hardener was oxidated thermally with increasing surrounding temperatures. The expansion of the free volume need in molecular motion and the reduction of the structural packing density through thermal oxidation process increased TSC between .alpha. peak and .betha. peak and decreased T$\_$g/.

• Korean journal of food and cookery science
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• v.28 no.6
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• pp.763-771
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• 2012

Physicochemical and sensory characteristics of pound cakes containing Angelica gigas NAKAI(Korean Angelica) with various levels of rice flour were investigated in this study. There were significant differences in the specific gravity of dough, and it had the lowest value of 0.848 in the control group. The weight of pound cakes was significantly increased by addition of rice flour, but the volume, specific volume and baking loss rate were significantly decreased by addition of rice flour. The moisture content and pH of pound cakes were found to increase with increasing rice flour content. DPPH radical scavenging activity of the control group was 51.02%, whereas pound cakes with rice flour ranged from 51.90~55.75%. The L value of brightness was increased, but a and b values were decreased significantly by addition of rice flour. In all of items of texture, the control group was higher than those of the pound cakes prepared with various levels of rice flour. Sensory evaluation scores in terms of appearance, flavor, taste, texture and overall preference for pound cakes showed that 50% and 75% substituted sample groups were higher than those of the other groups. The results of this study suggest that addition of 50~75% rice flour is the best substitution ratio for Korean Angelica pound cakes.

• The Korean Journal of Food And Nutrition
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• v.31 no.1
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• pp.195-201
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• 2018

This study was intended to investigate the characteristics of muffins prepared with allulose which is low-calorie and physiologically functional rare sugar. Volume and specific volume of muffins increased significantly with allulose addition, but not with its contents. Muffin heights also increased as allulose was added more. Baking loss rate and moisture contents were not significantly different among samples. Allulose seemed to have nearly same water holding capacity with sucrose. Lightness of muffin crust and crumb both decreased, but redness and yellowness increased according to allulose, the reducing sugar addition by Maillard reaction. In the texture profile analysis, Hardness of AL100 was higher significantly (p<0.05) and springiness, cohesiveness and fracturability increased according to the allulose contents. In the sensory evaluation, AL0 was the sweetest and AL0 and AL25 got higher overall acceptance score. Physical characteristics were not different (p<0.05) among AL0, Al25 and AL50. As a result, 25% sucrose substitution with allulose can provide low-calorie, anti-hyperglycemic and tasty muffin.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.10
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• pp.1474-1481
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• 2011

This study investigated the physicochemical characteristics of Korean wheat flour substituted for 0%, 15%, 30%, 45%, and 60% durum rimachinata wheat in order to develop a Korean wheat pasta suitable for consumer-preferred soft textures. The particles of Korean wheat that were less than 250 ${\mu}M$ were 87.03% of all particles, while 68.7% of durum rimachinata had particles more than 250 ${\mu}M$ in size. Durum rimachinata had more protein (13.84${\pm}$0.03) and ash (0.70${\pm}$0.02) than Korean wheat. In farinograph characteristics, water absorption, development time, stability, and weakness increased as the amounts of substituted Korean wheat flour increased. Also, the gelatinization characteristics of the amylograph exhibited an increase of gelatinization temperature and decrease in maximum viscosity. However, maximum viscosity was shown to be more than 550 B.U. until 30% of the substitution level of Korean wheat flour to durum rimachinata wheat. Also, it did not affect the texture of the noodle product. We could make pasta with softness and springiness with less than a 15% substitution level of Korean wheat flour due to similar characteristics in cooking properties such as weight, volume, water absorption, turbidity, and cooking loss when compared to the control. L and a values increased, and the b value decreased in color as substitution amounts of Korean wheat flour increased. The hardness and adhesiveness of cooking noodles was shown to be a low value at more than a 30% substitution level of Korean wheat flour, and springiness, gumminess, and chewiness all exhibited high values. In a sensory evaluation, overall acceptability was shown to have the highest score in control. More than 30% of substitution of Korean wheat flour showed high preferences. Therefore, 15% of the substitution level of Korean wheat flour could be adapted in dough and cooking properties for making pasta-substituted Korean wheat. However, a texture analyzer and sensory evaluation of cooked pasta was shown to have a good quality at more than 30% substitution level of Korean wheat flour.

• Journal of the Korean Society of Food Culture
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• v.30 no.2
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• pp.206-212
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• 2015

The purpose of this study was to investigate the quality characteristics of cookies containing Ligularia fischeri powder (0, 1, 2, 3, 4%) substituted for flour. This study measured the density, pH, spread ratio, volume, color values, hardness, and sensory properties of cookies. The pH of cookie dough significantly decreased in response to addition of Ligularia fischeri powder (LFP) at all levels. The spread factor of cookies also significantly increased with higher LFP content. In addition, Hunter's color L, a, and b values significantly decreased with increasing LFP content. According to hardness measurement, substitution of 1~4% LFP resulted in increased hardness compared to the control. In the sensory evaluation, sensory scores for color, flavor, and overall acceptability were highest in 2% Ligularia fischeri powder cookies. Thus, our results suggest that the optimum amount of Ligularia fischeri powder added to cookies was 2%. These results suggest that Ligularia fischeri powder can be applied to cookies to achieve high quality and functionality.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.3
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• pp.502-512
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• 2015

This study was conducted to investigate the physical, textural and sensory properties of sponge cake prepared with different amounts of radish leaf powder. The specific gravity and viscosity of cake batter and cooking loss of cake increased with an increasing amount of radish leaf powder, whereas specific loaf volume and moisture content of cake decreased. Lightness, redness and yellowness of crust and crumb decreased with increasing radish leaf powder content. Measurements using a texture analyzer showed that hardness, chewiness, gumminess, adhesiveness and fracturability of sponge cake tended to increase in proportion to the amount of radish leaf powder in the formula. In the sensory evaluation, sponge cake prepared with 5% radish leaf powder was similar to the control in terms of moistness, softness, chewiness and springiness. These results suggest that adding 5% radish leaf powder is the best substitution ratio for sponge cake.

• BMB Reports
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• v.28 no.4
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• pp.363-367
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• 1995

E. coli methionyl-tRNA synthetase is one of the class I tRNA synthetases. The Tryptophane residue at the position 461 located in the C-terminal domain of the enzyme is a key amino acid for the interaction with the anticodon of $tRNA^{Met}$. W461 was replaced with other amino acids to determine the chemical requirement for the interaction with the anticodon of $tRNA^{Met}$. Saturation mutagenesis at the position 461 generated a total of 12 substitution mutants of methionyl-tRNA synthetase. All the mutants showed the same in vivo stability as the wild-type enzyme, suggesting that the amino acid substitutions did not cause severe conformational change of the protein The mutants containing tyrosine, phenylalanine, histidine and cysteine substitutions showed in vivo activity while all the other mutants did not. The comparison of the in vitro aminoacylation activities of these mutants showed that aromatic ring structure, Van der Waals volume and hydrogen bond potential of the amino acid residue at the position 461 are the major determinants for the interaction with the anticodon of $tRNA^{Met}$.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.12a
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• pp.595-599
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• 1999

본 논문에서는 카오스 현상을 나타내는 수식을 변형하여 암호시스템이나 PN(pseudo-noise)시퀸스에 적용하기 위하여 복잡한 카오스 신호를 발생시키는 하이퍼카오스 VP 사상(HVPM, Hyper chaos Volume Preserving Maps)과 이들간의 카오스 동기화를 제안한다. 단계별 모듈러(modulus) 함수를 이용하여 랜덤한 카오스 신호를 발생시키기 위하여 이산시간(discrete-time) HVPM 모델을 설정하고, 수치해석 실험으로 아날로그 카오틱시퀸스(CAS. chaotic analog sequence)의 특징을 분석한다. 그리고 HVPM의 신호를 기존의 단순한 PC(Pecora, Carroll)방법을 응용한 치환동기화 (synchronous substitution)를 이용하여 구동 및 응답시스템간의 카오스 동기화(chaos synchronization) 제어를 한다. 수치실험에서 카오스 신호가 갖는 특징들을 확인할 수 있었으며, 치환동기시스템에서 효과적인 카오스 동기화가 수행됨을 증명할 수 있었다.

• The Korean Journal of Food And Nutrition
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• v.16 no.4
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• pp.321-327
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• 2003

The reaction rates of 4-ethyl pyridine with p-methyl benzylbromide have been measured by conductometry in acetonitrile, and the rate constants of these reactions are determined in accordance with various temperatures (20, 25, 30$^{\circ}C$) and pressures (1, 200, 500, 1000 bar). The rate constants increased with the higher pressure and temperature. The activation energies and activation parameter values of these reactions are calculated by determination of the rate constants the same. The activation volume, activation compressibility coefficient and the activation entropy are all negative. The result of kinetic studies for the pressure show that this reaction proceeds in typical bimolecular nucleophilic substitution reaction.

• Korean Journal of Crystallography
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• v.14 no.2
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• pp.110-114
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• 2003

LiAl/sub 0.24/Mn/sub 1.76/O/sub 4-y/S/sub y/ (y=0, 0.02) were synthesized by the sol-gel method. Both structures were refined by Rietveld method, its structure refined as a cubic spinel, space group Fd-3m, a=8.17937(30) Å and 8.18331(19) Å respectively. Though it has been made a charge/discharge experiment above 20 times, there was no change of 3 V/4 V capacity degradation. It was considered that the volume change of MnO/sub 6/ octahedron induced by sulfur substitution plays a key role in keeping the 3 V/4 V capacity. The refined composition of the compound could be confirmed with the ICP analysis.