• Macromolecular Research
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• v.9 no.1
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• pp.37-44
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• 2001

A premixing effect for the properties of carbon black-filled rubber compounds was investigated using biblends of natural rubber (NR), styrene-butadiene rubber (SBR), and butadiene rubber (BR). Degree of mixing of the biblends was controlled by preblending time of 0.0, 2.5, and 5.0 min. Mooney viscosities of the compounds decreased by increasing the preblending time. Of three carbon black-filled compounds of NR/SBR, NR/BR, and SBR/BR compounds, only the SBR/BR blends showed a specific cure characteristics depending on the preblending time. For the bound rubber composition, the NR content was higher than SBR and BR. The difference in the rubber composition ratio of the bound rubber became smaller with increasing the preblending time. Physical properties of the vulcanizates such as hardness, modulus, tensile property, abrasion loss, and tans were also compared. Differences in properties of the compounds were discussed with miscibility of the dissimilar rubbers and degree of mixing.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.6
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• pp.651-655
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• 1995

A simulation study on detection of linkage between genetic markers and QTL in backcross design was conducted. The effects of various sample sizes and the degree of QTL dominance on detention of linkage were examined by using a simple regression analysis. The results indicated that as sample size increased, the standard error of the estimated slope became smaller. When the dominance effect of QTL was complete, the estimated slope tended to be negative but was statistically not significant at all with type I error of greater than 50%. With complete linkage between genetic Marker and QTL, the estimated intercept value was smallest but the estimated slope was largest as expected. In most cases with various degree of dominance and sample sizes, when the actual recombination rate became larger, greater values were obtained for the slope except in the case of complete dominance of QTL.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.558.2-558
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• 2001

The aims of this study are (1) to investigate the relation of irradiation mode, polymerization shrinkage and degree of cure of composite resin and(2) it effect on micorleakage of class V restorations. VIP(BISCO Dental Products, Schaumburg, IL, USA) and Optilux 501 (Demetron/Kerr, Danbury, CT, USA) curing lights were used for curing Z-250 composite resin following irradiation mode: VIP 200㎽d, VIP 400㎽, VIP 600㎽, pulse-delay(200㎽ 3sec, 5min wait, 600㎽ 30sec), Optilux R mode.(omitted)

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.555-555
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• 2001

The aims of this study are (1) to investigate the relation of irradiation mode, polymerzition shrinkage and degree of cure of composite resin and (2) it effect on microliakage of calss V restorations. VIP(BISCO Dental Products, Schaumburg, IL, USA) and Optilux 501(Demetron/Kerr, Danbury, CT, USA) curing lights were used for curing Z-250 composite resin following irradiation mode: VIP 200㎽, VIP 400㎽, VIP 600㎽, pulse-delay(200㎽ 3sec, 5min wait, 600㎽ 30sec), Optilux C mode, Optilux R mode.(omitted)

• Korea-Australia Rheology Journal
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• v.15 no.4
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• pp.179-185
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• 2003

Associating polymers act as flocculants in colloidal suspensions, because the hydrophobic groups (hydrophobes) can adsorb onto particle surfaces and create intermolecular cross-linking. The steady-shear viscosity and dynamic viscoelasticity were measured for suspensions flocculated by multichain bridging of associating polymers. The effects of surfactant on the suspension rheology are studied in relation to the bridging conformation. The surfactant molecule behaves as a displacer and the polymer chains are forced to desorb from the particle surfaces. The overall effect of surfactant is the reduction of suspension viscosity. However, the additions of a small amount of surfactant to suspensions, in which the degree of bridging is low, cause a viscosity increase, although the number of chains forming one bridge is decreased by the forced desorption of associating polymer. Since the polymer chains desorbed from one bridge can form another bridge between bare particles, the bridging density over the system is increased. Therefore, the surfactant adsorption leads to a viscosity increase. The surfactant influences the viscosity in two opposing ways depending on the degree of bridging.

• Journal of Environmental Science International
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• v.7 no.6
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• pp.753-759
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• 1998

In physical and reactive extraction of acrylic acid using various solvents the equilibrium characteristics of extraction were investigated. The degree of extraction in reactive extraction with Tri-n-octylamine(TOA) was 1.5~3 times than that in physical extraction. Distribution ratio was constant in methyl isobutyl ketone(MIBK) and n-butylacetate(n-BAc) but was increased with increasing the concentration of acrylic acid in benzene and chloroform. It can be explained by formation of dimers. Maximum extraction leadings of acrylic acid were three in benzene and were two in MIBK, chloroform and n-BAc, and it was found that acrylic acid was extracted as the form of $A_3$R In benzene and $A_2R$ in MIBK, chloroform and n-BAc. In effect of solvent, the degree of extraction was increased as he difference of solubility parameter of solvent and solute was decreased, and as dielectric constant of solvent was increased.

• Korean Journal of Rural Living Science
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• v.8 no.2
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• pp.125-129
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• 1997

The effect of mugwort powder on some physicochemical properties of rice flour, the viscosity of rice flour pastes and the degree of gelatinization of pastes and gels were investigated. By addition of mugwort, water binding capacity, swelling power, and solubility of rice flour were increased, also the viscosity and, the degree of gelatinization of rice flour pastes and gels were increased. Generally wet rice flour-mugwort pastes and gels were better than those of dry rice flour-mugwort. And viscosity and gelatinization of the rice-mugwort pastes and gels were decreased slightly during storage at $20^{\circ}C$ for 7 days.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.263-264
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• 2021

The purpose of this study is to empirically confirm the effect of the characteristics of construction workers on the occurrence of defects in construction. In this study, the degree of direct construction is measured through the ratio of the direct recruitment and outsourcing manpower of the original contractor, and the effect of this on the occurrence of defects is empirically analyzed using financial data. In addition, it is verified whether the degree of defect occurrence varies depending on the job skill level of the direct hired personnel inputted to the construction. Through this, it will be possible to prepare an argument for revitalizing the direct construction of construction companies and an opportunity to promote it.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.155-160
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• 2001

A milling process with 45 degree chamfered inserts produces a perfect flat surface only in theory. It is due to many unwanted factors including thermal effect, dynamic effect, the problem of the controller used and the problem of accuracy of the machine tool. In this study, introduced is a method to improve the surface roughness by redesigning of the chamfer angle of the insert, which traditionally has been 45 degree. First, the relationship between the fixed machine coordinate and the relative coordinate on the insert is derived. This transfer matrix is used to determine the new insert angle to maximize the flatness of the machined surface. A newly designed insert is manufactured, and used to carry out the experiment. It is proved that she insert designed by the proposed method produced a much flatter surface than a traditional one.

• The Journal of Korean Physical Therapy
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• v.13 no.3
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• pp.613-624
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• 2001

Backgroun and purpose: The purpose of this study was to find out the effect of high heel shoes on lumbar lordosis for young ladies. The most of ladies wear high heel shoes at least 4 to 5 days a week. Subjects: Subjects were 30 young ladies age between 20 to 30 years old who go to the Sahm Yook University. Methods: Participants were static standing position with bear feet, tennis shoes. and 6cm high heel shoes each different time. The ankles of subjects were 15 degree plantar flexion with 6cm high heel shoes. Metrecom Skeletal Analysis System v. 3. 10 was used to measure the lordosis of each subject. Results: The angle of the lordosis with high heel shoes showed the significant decrease omparing with the angle of lordosis with bear feet and tennis shoes. The mean difference is 2.57 degree. Conclusion: There is strong relationship between the high of heel with decreasing the lumbar lordosis(p<0.05).