• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.3
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• pp.181-185
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• 2004

Malignant tumor have hypoxic cell fraction, which makes radio-resistant and hypoxia in tumor is a result from the blood flow decrease caused by increase in blood flow resistance. Blood viscosity increase is major factor of increased blood flow resistance and it could be attributed to the decrease in blood deformability index. For the evaluation of the change of blood viscosity and blood deformability in oral squamous cell carcinoma, we perform the test of the change of those factors between the normal control group and oral squamous cell carcinoma cell patient group. Relative viscosity measured against distilled water was $5.25{\pm}0.14$ for normal control group, and $5.78{\pm}0.26$ for the SCC patient group and there was statistical significance between the groups. However, there was no significant difference between the groups in blood viscosity between the groups by tumor size (T1+T2 vs T3+T4). Also, there was no significant difference between the normal control group and SCC patient group in blood deformability index and between the groups by tumor size (T1+T2 vs T3+T4). Increase in blood viscosity was confirmed with this study and it can be postulated that modification blood viscosity might contribute to decrease of hypoxia fraction in oral squamous cell carcinoma, thus improve the effect of radiotherapy and it can be assumed that the main factor of blood viscosity increase is not decrease of blood deformability in oral squamous cell carcinoma.

• Elastomers and Composites
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• v.35 no.2
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• pp.106-114
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• 2000

The foam of ethylene vinyl acetate (EVA)/styrene-vinyl isoprene-styrene triblock copolymer(SVIS) blend was prepared to improve the shock-absorption and compression set characteristics at room temperature. The effects of blowing agent and blend ratio of EVA/SVIS on expansion ratio, cell structure and mechanical properties of the foam were investigated. As the SVIS content increased, the viscosity of blends was increased but the crosslinking rate was slow down, the expansion ratio was decreased. and the specific gravity was increased. At room temperature, the resilience was not affected by increasing the amount of blowing agent. The value of tan ${\delta}$ was increased by increasing the amount of SVIS. As a result, the value of compression set was decreased. This is due to the increased values of specific gravity and crosslinking density of the EVA/SVIS foam.

• Korean Journal of Agricultural Science
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• v.22 no.2
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• pp.180-187
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• 1995

In order to distinguish the honey in the market whether it is real or not simply and conviniently, the changes of water activity was investigated due to the addition of starch syrup and sucrose solution to the honeys such as Korean, Acacia, Chestnut and Mixed. The regression equations were obtained to predict the water activity of the honeys. In general, the honey was below 21% in moisture, below 0.6% in ash, 420 to 710cP in the viscosity, 0.57 to 0.62 in the water activity and 77 to 80brix in sugar content. The water activity of the samples were higher as the quantity of starch syrup and sucrose solution added increased. Starch syrup was more influence than sucrose solution. The regression equations between water activity and starch syrup concentration of honeys were obtained and $R^2$ value were higher than 0.90.

• Membrane Journal
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• v.6 no.4
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• pp.265-272
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• 1996

The (polymer/carrier) composite membranes for separating the metallic ion have been prepared by the water cast-method. The morphology of these membranes was affected by the physical properties of the spreading solution. The surface tension of the (polymer/18-crown-6) composite solution was decreased with increasing the concentration of 18-crown-6 compound and the surface tension of polymer solution decreased the following order PVC>PS>CA. The viscosity of CA solution decreased with increasing the contents of the 18-crown-6 compound, but PVC and PS solutions showed no significance changes according as the concentration of 18-crown-6 compound. In the composite solutions, the spreading ability was improved by' the cyclic 18-crown-6 molecules which acted as an electric buffer and diminished the intermolecular force between the polymer chains. The (polymer/18-crown-6) composite membrane was more uniform than that of the mono polymer membrane on the coagulation state of polymer, and the top and bottom sides of membrane showed also the more smooth structure according as the concentration increment of 18-crown-6 molecule.

• Polymer(Korea)
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• v.32 no.1
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• pp.1-6
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• 2008

The adhesion behaviors and processability of NBR as a sealing material were investigated. In order to find the optimum formulation, the adhesive properties and processability were observed as the change of the contents of acrylonitrile (ACN) in NBR. Effects of Mooney viscosity, filler, plasticizer and crosslinking agent on the adhesion behaviors were also studied. The contents of ACN in NBR have great effects on adhesion behaviors and processability in NBR sealing. To know the optimum condition of roll mixing, degree of dispersion was investigated. It was confirmed that degree of dispersion was influenced by various factors such as mixing order, time, and temperature. The crosslinking system was studied as the observation of sulfur system, peroxide system, crosslinking density, and structure. From the variation of the dry condition and hexamine contents, the relation between adhesive and NBR was studied. These results show the adhesion properties and processability are dependent on the contents of ACN and crosslinking system.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.693-699
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• 1997

The effects of mugwort juice on the gel properties of corn starch (CS), mung bean starch (MS), and potato starch (PS) were investigated. Water holding capacities of three starches were increased with addition of the juice. Solubilities of CS and MS were also increased. Swelling power was increased in CS but decreased in MS. Viscoamylogram showed that 5% addition of the juice lowered the initial gelatinization temperatures of CS and MS, but raised the temperature of PS. While peak viscosities of CS and MS pastes were decreased a little, the viscosity of PS paste was decreased remarkably from 2,280 BU to 845 BU. Addition of mugwort juice did not affect significantly the hardness of starch gels during 7 days of storage at $25^{\circ}C\;and\;4^{\circ}C$. Degrees of gelatinization of the starch gels were affected by addition of the juice, especially in PS, during storage. Freeze-thaw stabilities of three gels were not changed by addition of the juice. The starch gels added with the mugwort juice had smooth surface visually because the crude fibrous materials of mugwort were removed during juice preparation.

• Fire Science and Engineering
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• v.33 no.5
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• pp.19-27
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• 2019

Fire extinguishing composite materials based on low-viscosity epoxy resin (EP) and containing 50 wt% of encapsulated fire extinguishing agent (EFA) have been studied. The positive effect of the EP on the kinetics and temperature of the EFA decapsulation was established. The EP increases the decapsulation temperature of the EFA from 130 ℃ to 155 ℃ and changes the kinetics of the decapsulation. The epoxy matrix increases the thermal stability of the EFA more than 3.9 times compared to that of the pure EFA. The protective effect of the EP on the storage stability of the EFA was validated. The mass loss of EP-containing EFA at 60 ℃ and 80% humidity over 96 h is 0.4%. The mass loss of pure EFA under the same conditions is 15%. A similar effect was observed under ultraviolet radiation: the EP-containing EFA loses 0.8% at pure EFA mass of 6%. The testing of alternative polymer matrixes has been considered.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.615-626
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• 2016

In the paper, mild solvent soluble alkyl group modified epoxy resins were prepared via a three-step method; (1) the condensation reaction of dodecyl phenol (DP) and formaldehyde, (2) the crosslinking reaction of dodecyl phnol novolac compound (DPC) and bisphenol A diglycidyl ether, (3) the dodecyl phenol novolac epoxy resins containing fatty acid (DPFA) was prepared by introducing fatty acid to DPC. Equivalent ratios of DP and formaldehyde were 1.25~1.333/1.0. Equivalent ratio of DPC and bisphenol A diglycidyl ether (YD-128) was 1.0/2.0. Reactivity, viscosity, molecular weight, solvent solubility, and physical properties of DPFA were investigated. The result show that as the number of aromatic ring of DPFA increased, viscosity increased and solvent solubility improved. When we test the properties of coatings by blending the synthesized DPFA with a white pigment, DPFAC-5 using triphenylphosphine (TPP) as a ring-open catalyst showed optical performance for drying time, adhesion, hardness, impact resistance, acid resistance and storage stability.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.483-486
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• 1995

With a view to increase utility of ethanol fractionated fish skin gelatin as a food source, the effect of gelation condition on physical properties of the gelatin was investigated. The physical properties of gelatins treated with or without ethanol were improved with a concentration of gelatin increased. The properties such as gel strength, melting point and gelling point of 10% gelatin sol or gel were reached to maximum at pH 6.0 in ethanol treated gelatin and pH 5.0 in non treated one, respectively. Gel strength and melting point of both gelatin gels chilled for long time at low temperature were superior to those of both gelatin gels chilled for short time at high temperature. Gel strength, melting point and gelling point of ethanol treated gelatin gel or sol prepared under optimized gelation conditioning were superior to those of non treated one.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.818-823
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• 2002

Effects of pelleting, drying, conditioning, and additives on the characteristics of Yukwa (fried pellet) were determined. RVA maximum paste viscosity of Bandegi (waxy rice pellet) was the highest after 2 days of moisture conditioning process, and decreased 2 days later. Air bubbles in Bandegi were distributed uniformly but were not significantly affected by conditioning time. For higher expansion and softer texture of Yukwa, the optimum moisture content of dried and conditioned Bandegi was $14{\sim}17%$. The addition of soymilk and 25% alcohol (Soju) as additives was also effective for achieving higher expansion and soft texture of Yukwa, respectively. Larger air cells were distributed in the center and smaller ones on the edge of Yukwa.