• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.2
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• pp.129-138
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• 2005

Sediment texture, physical (porosity, water content, bulk density, grain density, and shear strength), and geoacoustic properties (compressional wave velocity and attenuation) were measured on eighteen core samples collected from the shelf off eastern Geoje Island, the South Sea of Korea. Based on these properties, the study area is divided into three different sub-areas: (1) Area I affected directly by the Nakdong River discharge; (2) Area II covered by the southern branch of the Nakdong River discharge; and (3) Area III dominated by relict sediment. Mean grain size, velocity, and bulk density decrease from Area $I(7.4\Phi,\;1528m/s,\;1.6g/cm^3,\;respectively)$ to Area $II(8.1\Phi,\;1485m/s,\;and\;1.5g/cm^3)$, and then increase rather rapidly in Area $III(1.4\Phi,\;1664m/s,\;and\;2.2g/cm^3)$. Porosity, on the other hand, exhibits an opposite trend, increasing from Area $I(64.5\%)$ to Area$II(73.9\%)$ and then decreasing significantly in Area $III(32.9\%)$ From the results measured and calculated, we suggest a specified geoacoustic model in the study area.

• Journal of Sericultural and Entomological Science
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• v.41 no.1
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• pp.41-47
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• 1999

Silk fibroin dissolved in highly concentrated calcium chloride and ethanol mixture aqueous solution turned into gel under suitable conditions. Preparation conditions and properties of gel were investigated as a function of parameters such as pH of solution, fibroin concentration, glycerol concentration and molecular weight. When pH of silk fibroin aqueous solution was near the isoelectronic point(pH 3.9~4.0), gelation occurred rapidly and strength of gel was stonger than that of pH-unadjusted due to electrostatic repulsion decrease between silk fibroin macromolecules. As concentration of silk fibroin and glycerol was higher, gelation occurred more rapid. FT Infra-red spectra of freeze-dried fibroin gel showed that gelation was derived by intermolecular anti-parallel ${\beta}$-sheet structure formation. In addition to, it was found that white-precipitate occurred instead of gelation when aqueous silk fibroin was treated by enzyme(flavouzyme), however, after flavouzyme-treated silk fibroin aqueous solution was centrifugated gelation occurred instantly. The results of differential scanning thermal analysis and infra-red spectroscopy showed that thermal stability and crystallinity of enzyme-hydrolyzed fibroin are superior to those of unhydrolyzed fibroin.

• Food Science of Animal Resources
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• v.26 no.4
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• pp.517-524
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• 2006

We investigated the effect of different kinds of dietary fats on the fatty acid composition, cholesterol content and quality of hens' eggs. The Haugh units, breaking strength, shell thickness and yolk color were not significantly different among the test groups. The type of dietary fat fed each test group notably altered the polyunsaturated fatty acid composition and cholesterol content of egg yolk. The n-6 fatty acid content of egg yolk was highest in the corn oil fed group being 31.61%, and this tended to decrease in the tallow, linseed oil and fish oil fed groups(P<0.05) in that order. The n-3 fatty acid content of egg yolk tended to increase in the linseed oil and fish oil fed groups with values of 9.74% and 5.16%, respectively(p<0.05). The increase of n-3 fatty acids in the yolk resulted in a reduced cholesterol content of the eggs. The cholesterol content ranged from $15.98{\sim}18.37mg/g$ of yolk or $227{\sim}261mg/60g$ of egg(p<0.05). The cholesterol content of egg yolk was highest in the tallow fed group, and significantly reduced to 13.01% in the fish oil group, 11.49% in the linseed oil group and 6.91% in the corn oil group(p<0.05). This result suggests that it is possible to reduce the cholesterol content or to increase the n-6 and n-3 polyunsaturated fatty acid contents in eggs by the manipulation of dietary fats.

• Physical Therapy Korea
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• v.11 no.1
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• pp.53-67
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• 2004

This simulation study investigated the characteristics of normal gait, $30^{\circ}$ crouch gait, $30^{\circ}$ crouch/equinus gait, $45^{\circ}$ crouch gait, $45^{\circ}$ crouch/equinus gait. The knee flexion angles were restricted using a specially designed orthosis. This study was carried out in a motion analysis laboratory of the National Rehabilitation Center. Fifteen healthy male subjects were recruited for the study. The purposes of this study were (1) to compare spatiotemporal parameters, kinematics, and kinetic variables in the sagittal plane among the different gait, (2) to investigate the secondary compensatory strategy, and (3) to suggest biomechanical physical therapy treatment methods. The pattern and magnitude observed in each condition were similar to those of normal gait, except the peak knee extension moment of the unrestricted ankle motion-crouch gait. However, the speed of the $45^{\circ}$ crouch gait was half that of a normal gait. The ankle joint moment in the crouch/equinus gait showed the double-bump pattern commonly observed in children with spastic cerebral palsy, and there was no significant difference in gait speed as compared with normal gait. The peak ankle plantar-flexor moment and ankle power generated during the terminal stance in the crouch/equinus conditions were reduced as compared with normal and $45^{\circ}$ crouch gaits (p<.05). The crouch/equinus gait at the ankle joint was an effective compensatory mechanism. Since ankle plantarflexion contracture can be exacerbated secondary to the ankle compensatory strategy in the crouch/equinus gait, it is necessary to increase the range of ankle dorsiflexion and the strength of plantarflexion simultaneously to decrease the abnormal biomechanical advantages of the ankle joint.

• Geomechanics and Engineering
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• v.14 no.3
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• pp.247-255
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• 2018

Soil stabilization can make the soils becoming more stable by using an admixture to the soil. Lime stabilization enhances the engineering properties of soil, which includes reducing soil plasticity, increasing optimum moisture content, decreasing maximum dry density and improving soil compaction. Silica fume is utilized as a pozzolanic material in the application of soil stabilization. Silica fume was once considered non-environmental friendly. In this paper, the materials required are kaolin grade S300, lime and silica fume. The focus of the study is on the determination of the physical properties of the soils tested and the consolidation of kaolin mixed with 6% silica fume and different percentages (3%, 5%, 7% and 9%) of lime. Consolidation test is carried out on the kaolin and the mixtures of soil-lime-silica fume to investigate the effect of lime stabilization with silica fume additives on the consolidation of the mixtures. Based on the results obtained, all soil samples are indicated as soils with medium plasticity. For mixtures with 0% to 9% of lime with 6% SF, the decrease in the maximum dry density is about 15.9% and the increase in the optimum moisture content is about 23.5%. Decreases in the coefficient of permeability of the mixtures occur if compared to the coefficient of permeability of kaolin soft clay itself reduce the compression index (Cc) more than L-SF soil mix due to pozzolanic reaction between lime and silica fume and the optimum percent of lime-silica fume was found to be (5%+6%) mix. The average coefficient of volume compressibility decreases with increasing the stabilizer content due to pozzolanic reaction happening within the soil which results in changes in the soil matrix. Lime content +6% silica fume mix can reduce the coefficient of consolidation from at 3%L+6%SF, thereafter there is an increase from 9%L+6%SF mix. The optimal percentage of lime silica fume combination is attained at 5.0% lime and 6.0% silica fume in order to improve the shear strength of kaolin soft clay. Microstructural development took place in the stabilized soil due to increase in lime content of tertiary clay stabilized with 7% lime and 4% silica fume together.

• Information Systems Review
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• v.11 no.1
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• pp.19-47
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• 2009

Many products today tend to adopt a convergence approach by adding new features or functionalities to the existing products. The convergence, however, results in both positive and negative effects on usage of products, and thus demonstrates the characteristics called "paradox of technology." On the one hand, the added functionalities or features will increase the usefulness of the products. On the other hand, the convergence increases complexity of learning and usage of products and may decrease satisfaction or user evaluations. This study provides an empirical evidence of this paradox through investigation of telematics, one of the exemplary products of convergence services. Our research model is designed to test the existence of the "paradox of technology" and includes variables such as variety of functions, complexity of usage, perceived usefulness, service evaluation, and service fit. The proposed research model and subsequent hypotheses are empirically tested using 149 survey responses from telematics users. We have found that the variety of functions is positively associated with perceived usefulness, but is negatively associated with the complexity of usage. The data analysis reveals that the perceived usefulness has more significant impacts on service evaluation than the complexity of usage does. Furthermore, the strength of causal relationships among these variables is partially moderated by the degree of service fit. This study thus highlights the paradox of technology in explaining user attitudes and beliefs associated with convergence services.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.3
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• pp.333-341
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• 2014

Since distribution and preservation of cultural artifacts in the submarine sediments are directly affected by not only ocean currents and tides, but also their composition, it is very important to investigate geological characteristics of sediments and ocean-sediment interactions for maritime archaeological survey. Physical properties of submarine sediments, which are collected by grab sampler and vibro-corer, are analyzed in order to investigate effects of submarine environment on development of maritime archaeological survey techniques. Result of physical property analysis showed that bulk density, shear strength, and magnetic susceptibility increase with depth, while water contents and porosity decrease with depth. Since the magnetic susceptibility of bedrock is about 40 times that of submarine sediments, it might impact greatly on the response of magnetic survey. Physical properties of sediments with depth and sediment classification by Folk's ternary diagram indicate that submarine sediment mainly consists of silt, and cultural artifacts can not penetrate no deeper than 1.5 m in sediments.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.9
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• pp.1318-1323
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• 2008

Corn distiller's dried grains with solubles (DDGS) is a completely new feed ingredient in the Korean feed market. There is an ever increasing need for the Korean feed industry to import and make the best of it as a high protein and high energy feed ingredient. A layer feeding trial was conducted for 10 weeks to investigate the effects of addition of light-colored DDGS to layer diets on laying performance, egg qualities and yolk fatty acid composition. Also, the economics of using DDGS in the Korean situation was analyzed. Nine hundred Hy-line Brown layers, 24 weeks of age, were employed in a feeding trial consisting of four dietary treatments (0, 10, 15, and 20% DDGS), and five replicates per treatment. All experimental diets were prepared as iso-protein (17%) and iso-calorie (TMEn 2,780 kcal/kg). The use of DDGS up to 20% in layer diets did not exert any influence on feed intake, laying rate, total egg mass, mean egg weight and feed conversion ratio (p>0.05). The color and breaking strength of eggshell, as well as the albumin height and Haugh unit were not affected by the addition of DDGS up to 20% in the diet. The yolk color was significantly increased by DDGS supplementation (p<0.05). As the DDGS level increased, the oleic acid content decreased, and the linoleic acid increased (p<0.05) in egg yolk. The degree of saturation of yolk fatty acids was not affected by DDGS supplementation. The inclusion of light-colored DDGS up to 20% in layer diets resulted in a decrease of feed cost per kg without any undesirable effect on laying performance. In conclusion, the light-colored DDGS (L* 56.65) could be used up to 20% in layer diets without any harmful effect on laying performance, and possibly provide economic benefits to the Korean poultry industry.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.218-224
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• 2014

Biodegradable conductive composite films of polylactic acid(PLA) were prepared with various amounts of polyaniline(PAni) doped with dodecylbenzenesulphonic acid (DBSA) by solution blending technique to identify their mechanical and electric properties. 15 mol% of DBSA doped PAni was easily obtained by polymerizing of aniline in the presence of APS and DBSA in THF at $0^{\circ}C$. FE SEM characterization showed that PAni were well spread on the PLA domains. The tensile strength of composite film with 15 wt% of PAni was significantly decreased from $565.3kg_f/cm^2$ for PLA film itself to $309.7kg_f/cm^2$. Elongations of all PAni/PLA composite films were also decreased up to 3-6%. Electrical conductivity of $2.9{\times}10^{-3}$ S/cm could be achieved for the composite film containing 15 wt% of PAni-DBSA. Thermal stability of these composite films measured by thermogravimetric analysis(TGA) showed a slight decrease with the amount of PAni in PAni/PLA composite films at temperature lower than $300^{\circ}C$. However, the final weight of char was strongly depended with the amount of PAni in original composite films. Conclusively, PAni/PLA composite films containing more than a 15 wt% of PAni could be used for intercepting electromagnetic and preventing electrostatic applications.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.269-275
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• 2017

Shipwreck remains below the seabed not only effect the ocean currents and tides, but influence the physical properties of sediments and sedimentary environments that comprise the seabed. In particular, the influence of local shipwrecks discovered buried in the seabed on the sediment is visible. In this study, sediments were collected from the surrounding area of Taean Mado No.3 shipwreck using grab samplers and vibro-corers. The physical properties of these sediments were analyzed to evaluate the impact of the Taean Mado shipwreck No.3 remains. Sediment core analysis by means of density and ultrasonic velocity showed that shear strength tended to increase with depth, whereas moisture content and porosity tended to decrease with depth. Grain size analysis results are shown in terms of Folk's classification, where the grain size of the core samples in the study area indicate mud or sandy mud, and that of the grab sample indicates a muddy sand. Results of the sedimentation rate analysis indicate a rate of 2.84 cm/year and carbon dating of the 150 cm deep seashell indicates the Neolithic age. These sediments were analyzed for the study of the relationship between the Taean Mado shipwreck No.3 remains and the physical properties of the sediment.