• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.289-290
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• 2003

Polymer blending constitutes a most useful method for the improvement or modification of the physicochemical properties of polymeric materials. So polymer blends have gained an increasing interest in both industrial and scientific fields. Some of the polymer blends exhibit unusual properties, unexpected from homopolymers. An important property of a polymer blend is the miscibility of its component, because it affects the mechanical properties, the morphology, its permeability and dogradation [1,2]. (omitted)

• 방사선산업학회지
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• 제4권3호
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• pp.259-263
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• 2010

Carbon fibers are used as a reinforcement material in an epoxy matrix in advanced composites due to their high mechanical strength, rigidity and low specific density. An important aspect of the mechanical properties of composites is associated to the adhesion between the surface of the carbon fiber and the epoxy matrix. This paper aimed to evaluate the effects of electron beam irradiation on the physicochemical properties of carbon fibers to obtain better adhesion properties in resultant composite. Chemical structure and surface elements of carbon fiber were determined by FT-IR, elemental analysis and X-ray photoelectron spectroscopy, which indicated that the oxygen content increased significantly with increasing the radiation dose. Thermal stability of the carbon fibers was studied via the thermalgravimetric analysis. Surface morphology of carbon fiber was analyzed by scanning electron microscope. It was found that the degree of surface roughness was increased by electron beam irradiation.

• Asian-Australasian Journal of Animal Sciences
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• 제16권2호
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• pp.269-276
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• 2003

We studied the gel properties of porcine collagen with microbial transglutaminase (MTGase) as a catalyst. A creep meter was used to measure the mechanical properties of gel. The results showed samples with high concentration of MTGase gelled faster than those with a low concentration of MTGase. The gel strength increased with incubation time and the peaks of breaking strength for 0.1, 0.2 and 0.5% MTGase were obtained at 40, 20 and 10 min incubation time, respectively. According to SDS-PAGE, the MTGase was successfully created a collagen polymer with an increase in molecular weight, whereas no change in formation was shown without MTGase. The sample with 0.5% MTGase began to polymerize after 10 or 20 min incubation at $50^{\circ}C$, and complete polymerization occurred after 40-60 min incubation. Scanning electron microscopic analysis revealed that the gel of porcine collagen in the presence of MTGase produced an extremely well cross-linked network. The differential scanning calorimetric analysis showed the peak thermal transition of porcine collagen gel was at $36^{\circ}C$, and that with MTGase no peak was detected during heating from 20 to $120^{\circ}C$. The melting point of porcine collagen gel could be controlled by MTGase concentration, incubation temperature and protein concentration. Knowledge of the structural and physicochemical properties of porcine collagen gel catalyzed with MTGase could facilitate their use in food products.

• 한국식품영양학회지
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• 제19권4호
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• pp.532-538
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• 2006

Physicochemical and sensory characteristics of the jelly prepared with various levels of resistant starch were investigated in this study. Water content of RS10 sample group had significantly the highest value of 12.55% and that of the RS20 sample group had significantly the lowest value of all (p<0.05). RS20 sample group had significantly the highest value in sweetness. The value of pH were decreased with increased levels of the resistant starch in jelly preparation. The Hunter L values were not significantly different among the sample groups, but the RS20 sample group had the highest value of all. The hardness was increased as the addition levels of the resistant starch was increased. Results of sensory characteristics of RS20 sample group showed significantly the higher values in strawberry aroma, sweetness and after taste and significantly the lower value in stickiness than those in the other sample groups at p<0.05. Strawberry flavor, springiness and glossiness of RS5 sample group had significantly the largest values of all (p<0.05). The sensory properties of clarity and glossiness were negatively correlated with the mechanical properties of the color value and hardness at p<0.05. Sensory sweetness and after taste showed negative correlation with the values of pH in jelly preparation(p<0.05).

• 한국가시화정보학회지
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• 제16권3호
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• pp.40-46
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• 2018

The surface structure of the electrospun polymer fibers depends on the polymer concentration, the type of solvent used, applied voltage and so on. To make a desired surface, it is important to understand the effects of the physicochemical properties to form a stable Taylor cone and jet dispensation. We observed the formation of Taylor cone and a consequent structure of fiber by controlling the parameters of applied voltage, solution concentration, solvent and collector effectively. Once the surfaces were fabricated, the structures were analyzed using optical imaging technologies. As the solution concentration was increased, the smooth fibers were formed. In addition, different solvent ratios determined the viscosity and the surface tension of solutions. As a result, with decreased viscosity and increased surface tension, thin fibers were obtained by electrospinning. Furthermore the aligned nanofiber was successfully created by using drum collector.

• 동아시아식생활학회지
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• 제15권3호
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• pp.300-305
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• 2005

Along with development of modem medicine, the average life span has been increased but diseases of lifestyle such as cancer, obesity atheroscerosis, cardiac disorder become social issues. This study was designed to examine the availability of the functional food by adding chitosan-oligosaccharide to Korean traditional food, Soybean Dasik. For the study, 0, 30, 50 and $70\%$ of chitosan-oligosaccharide power that contains $23\%$ of chitosan-oligosaccharide were added to soybean Dasik in proportion to the total powder weight These were compared with the Soybean Dasik itself in relation to the physicochemical characteristics, sensory evaluation, and mechanical characteristics. The results of the research are as follows. Physicochemical characteristics showed that chitosan-oligosaccharide soybean Dasik had less ash, K, and Mn. As for the result of sensory evaluation, Dasik added $0\%$ chitosan-oligosaccharide was evaluated very good in its color. Sweetness and softness was good on $0\%\;30\%\;and\;50\%$ ones, while moistness and overall quality on $30\%\;and\;50\%$ ones. As the test results of mechanical characteristics, the chitosan-oligosaccharide soybean Dasik was good for hardness, cohesiveness, gumminess, and brittleness, especially on $0\%\;30\%\;and\;50\%$ ones. Springiness was good in all groups. In color, L value of chitosan-oligosaccharide soybean Dasik decreased but a and b values increased as the substitution percentage increased Therefore, the right amount of addition fit for the production properties was $30-50\%$ chitosan-oligosaccharide of total powder weight.

• 한국식품조리과학회지
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• 제21권6호통권90호
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• pp.859-866
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• 2005

The purpose of this study was to investigate the effects of the addition of various concentrations of antler powder on the physicochemical and sensory characteristics of mango jelly As for pH and viscosity of the mango jelly, antler powder added group showed higher pH and viscosity than that of control group. As for turbidity, absorbance increased significantly(p<.001) by the addition of antler while permeability decreased. The syneresis increased with the passage of time. According to sensory evaluation, Sleekness showed the highest by adding $0.2\%$ antler powder in mango jelly. The hunter color L and b value decreased significantly(p<.001) by adding antler powder. The mechanical properties such as hardness, springiness, cohesiveness and brittleness were highest by adding $1.0\%$ antler powder while gumminess was highest by adding $0.2\%$ antler powder in mango jelly. Overall quality, taste, appearance, texture were most superior by adding $0.2\%$ antler powder in mango jelly. From these test results, the optimum recipe for mango jelly added with antler powder was $0.2\%$ of antler powder, $10\%$ sugar, $\2%$ agar and 351.2ml of mango juice.

• Fibers and Polymers
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• 제7권3호
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• pp.286-294
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• 2006

This study has examined the flexural properties of natural and chemically modified coir fiber reinforced cementitious composites (CFRCC). Coir fibers of two different average lengths were used, and the longer coir fibers were also treated with a 1% NaOH solution for comparison. The fibers were combined with cementitious materials and chemical agents (dispersant, defoamer or wetting agent) to form CFRCC. The flexural properties of the composites, including elastic stress, flexural strength, toughness and toughness index, were measured. The effects of fiber treatments, addition of chemical agents and accelerated ageing of composites on the composites' flexural properties were examined. The results showed that the CFRCC samples were 5-12 % lighter than the conventional mortar, and that the addition of coir fibers improved the flexural strength of the CFRCC materials. Toughness and toughness index, which were associated with the work of fracture, were increased more than ten times. For the alkalized long coir fiber composites, a higher immediate and long-term toughness index was achieved. SEM microstructure images revealed improved physicochemical bonding in the treated CFRCC.

• 폴리머
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• 제28권3호
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• pp.253-262
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• 2004

독성이 없고 생분해성과 생체적합성을 가지는 폴리(비닐 알코올)/키토산 블렌드 필름들은 용액상태로 캐스팅 하여 제조하였다. 블렌드 필름들의 물리화학적 특성들의 변화는 여러 가지의 분석방법을 통해 조사하였다. 항균특성의 고찰에서 키토산이 10 wt% 이상 함유된 모든 블렌드 필름의 정균율은 99.9%로 우수하게 나타났다. 수분율은 키토산의 함량이 증가함에 따라 증가하나 팽윤도는 감소하였다. 키토산 함량이 15 wt% 내에서는 블렌드 필름의 용융온도와 결정화온도가 키토산의 함량에 따라 증가하였다. 또한, 키토산이 10, 15 wt% 함유된 블렌드 필름들은 용융온도가 각각 229와 228$^{\circ}C$로 순수 PVA보다 높은 값을 나타내었다. 그러나 키토산 함량이 20 wt% 이상일 경우 용융온도는 감소하였다. 블렌드 필름의 역학적 특성들은 습윤상태 및 건조상태 모두 키토산 함량이 증가함에 따라 증가한다 키토산 함량이 15 wt% 내에서 높은 인장강도를 나타낸다.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3829-3834
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• 2013

$H{\beta}$ (core)/SAPO-11 (shell) composite molecular sieve was synthesized by the hydrothermal method in order to combine the advantages of $H{\beta}$ and SAPO-11 for the methylation of naphthalene with methanol. For comparison, the mechanical mixture was prepared through the blending of $H{\beta}$ and SAPO-11. The physicochemical properties of $H{\beta}$, SAPO-11, the composite and the mechanical mixture were characterized by various characterization methods. The characterization results indicated that $H{\beta}$/SAPO-11 composite molecular sieve exhibited a core-shell structure, with the $H{\beta}$ phase as the core and the SAPO-11 phase as the shell. The pore diameter of the composite was between that of $H{\beta}$ and SAPO-11. The composite had fewer acid sites than $H{\beta}$ and mechanical mixture while more acid sites than SAPO-11. The experimental results indicated that the composite exhibited high catalytic performances for the methylation of naphthalene with methanol.