• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.321-335
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• 1999

Erbium(Er) doped LiNbO3(Er:LiNbO3) single crystal gibers were grown free of cracks along the c-axis by micro-pulling down method. the Er3+ concentration was distributed homogeneously along the growth axis. The samples for optical characterization were cut from as-grown single crystal fibers and polished. When the 980 nm light was incident on the sample, upconversion phenomena were observed at the green range of wavelength 510~570 nm. In addition, the intensity of upconversion was remarkably increased by increasing the concentration of Er2O3 dopant in as-grown Er:LiNbO3 crystals.

• Journal of the Semiconductor & Display Technology
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• v.16 no.1
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• pp.59-64
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• 2017

The general manufacturing problem can be described as the achievement of a predefined product quality with given equipment, cost and time constraints. Unfortunately, for some quality characteristics of a product such as surface roughness it is hard to ensure that these requirements will be met. Stainless steels STS 304 is frequently used as shaft materials in small fiber reinforced polymer(FRP) fishing boats. In this work, the dry turning parameters of STS 304 are optimized by using Taguchi method. The experiments were conducted at three different cutting speeds with three different feed and three different depth of cut. The cutting parameters are optimized using signal to noise ratio and the analysis of variance. The effects of cutting speed and feed on surface roughness was analyzed. The results revealed that the spindle speed is the more significant parameter influencing the surface roughness.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.07a
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• pp.95-96
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• 1999

The ultrafiltration behavior of dilute colloidal solution containing Si particles has been investigated. The experiments in cross flow mode have been performed at different operating condition by using the membrane with 20 kDa cut-off. The flux decline was due to the development of membrane fouling which was a dynamic process of two distinctive stages. For the high trans-membrane pressure, the pore blocking resistance was dominant at the initial period of filtraion and was followed by the cake resistance. And for the low cross flow velocity, the membrane fouling was governed by the cake filtration model at the initial stage of filtration process. Flux jump was observed temporally during the membrane filtration of mixed feed solution.

• Journal of Advanced Information Technology and Convergence
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• v.9 no.1
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• pp.89-102
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• 2019

Collagen can be used in building artificial skin replacements for treatment of burns and towards the reconstruction of bone as well as researching cell behavior and cellular interaction. The strength of collagen in connective tissue rests on the characteristics of collagen fibers. 3D confocal imaging of collagen fibers enables the characterization of their spatial distribution as related to their function. However, the image stacks acquired with confocal laser-scanning microscope does not clearly show the collagen architecture in 3D. Therefore, we developed a new method to reconstruct, visualize and characterize collagen fibers from fluorescence confocal images. First, we exploit the tensor voting framework to extract sparse reliable information about collagen structure in a 3D image and therefore denoise and filter the acquired image stack. We then propose to segment the collagen fibers by defining an energy term based on the Hessian matrix. This energy term is minimized by a min cut-max flow algorithm that allows adaptive regularization. We demonstrate the efficacy of our methods by visualizing reconstructed collagen from specific 3D image stack.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.867-873
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• 2010

This study investigated the corrosion properties of reinforced concrete with the addition of steel fibers. The transport properties of steel fiber-reinforced concrete such as permeable void, absorption by capillary action, water permeability and chloride diffusion were first measured to evaluate the relationship with the corrosion of steel rebar. Test results showed a slight increase on the compressive strength with the addition of steel fibers as well as considerable improvement of penetration resistance to mass transport of harmful materials into concrete. The addition of steel fibers in reinforced concrete accelerated the initiation of steel corrosion contrary to the expected results based on the measured transport properties. The NaCl ponding surface showed the spalling failure due to the corrosion expansion of steel fibers and the cut-surface around the steel rebar showed the localized steel fiber's corrosion. The wet-dry cycling with high chloride ions as well as high temperature seems to induce the increase of salt crystallization on the pores continually and the increased pressure with the steel fiber's corrosion on the pores caused the spalling failure on the exposed surface. The microcracking on the surface therefore accelerated the movement of water, chloride ions and oxygen into the embedded steel rebar. The mechanism affecting corrosion of embedded steel reinforcement with steel fibers in this study are not yet fully understood and require further study comprising of accurate experimental design to isolate the effect of steel fiber's potential mechanism on the corrosion process.

• Polymer(Korea)
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• v.24 no.5
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• pp.701-712
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• 2000

The continuous fiber reinforced composites of GF/PA were fabricated using a pultrusion resin impregnation apparatus and cut into pellets of 6 mm length. GF/PA pellets were then melt-mixed with PP resin to prepare new types of ternary composites, GF/PA/PP. Mechanical and rheological properties of such composites revealed to be better than conventional ternary composites due to the longer average glass fibers. Measurements also showed that the mechanical properties of the composites prepared by direct injection molding were higher than those of the composites prepared by injection molding followed by extrusion. To improve adhesions of fiber surfaces and polymer matrix, PP-MAH (maleic anhydride) has been introduced in the GF/PA/PP composites as a compatibilizer. It was found that PP-MAH did indeed improve surface adhesion between fibers and polymer matrix and that, as a result, various mechanical properties were markedly enhanced. Visualization of the phase structure in the samples was done by means of SEM. The surfaces of glass fibers in GF/PA/PP composites revealed that the fibers remained to be encapsulated by PA resin. However, pre-encapsulation did not persist in GF/PA/PP/PP-MAH composites due to the improvement of surface adhesion between fibers and polymer matrix, although resin sticking to the fiber was observed.

• Food Science of Animal Resources
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• v.44 no.1
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• pp.51-73
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• 2024

This study investigated how birth weight differences in piglets affected carcass and muscle fiber properties as well as meat quality at slaughter. Within litters, piglets were grouped according to their birth weight as either normal (NBW; 1.62-1.73 kg) or low (LBW; 1.18-1.29 kg). At 5 weeks of age, NBW piglets were randomly transitioned to control (C) or isocaloric high fat diets derived from non-dairy (HF), while LBW piglets were randomly transitioned to high fat diets derived from non-dairy (HF) or dairy sources (HFHD). Piglets were reared in individual pens under standardized housing and feeding conditions. Live weight was recorded weekly, and pigs were slaughtered at 12 weeks of age. Hot carcass weights, dressing percentages, lean meat yield, and primal cut proportions were determined. The m. longissimus thoracis was collected from the right side of the carcass for measurement of physical and chemical properties of meat and muscle fiber characteristics. Results indicated that LBW pigs compensated for their live weight compared to NBW pigs at 6 weeks of age. The mean muscle fiber diameter of LBW-HFHD group is significantly higher than NBW-C and NBW-HF group, and the type I muscle fiber diameter is significantly higher than NBW-C group. Dairy fat inclusion in LBW pig diet reduced carcass back fat thickness. This increased the calculated lean meat yield to be comparable to that of NBW pigs fed a commercial diet. Incorporating dairy-sourced high-fat into LBW pigs' diets appears to be an effective strategy for producing carcasses equivalent to NBW pigs.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.1
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• pp.98-112
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• 1996

Tho purpose of this study was to investigate hygienic and comfortable properties of socks. Materials are nine summer socks either frequently being worn or new products recently introduced to market. Three female and three male adults participated in this study. Through wearing experiment, the numbers of microbes on foot and sock were counted and subjective sensation was measured. The microbes were isolated and identified based on growth physiological characteristics. Nine different socks had smaller number of bacteria of sock than that of foot. The number of bacteria of sock was significantly related with that of foot in cotton socks, in piled cotton socks, in mesh cotton socks, in cotton+ nylon+ linen blended socks, in nylon socks. Total number of bacteria of tv cut finished socks was most small and total number of bacteria was increased in the order of ultra fresh finished socks, untreated cotton socks, nylon socks, cotton + nylon+ linen blended socks, mesh cotton socks, polyester+ nylcn+ linen blended socks, piled cotton socks, cotton socks. Total number of bacteria of cotton socks and piled cotton socks were significantly different from that of uv cut finished socks. Finished socks and .jocks has high air permeability had significantly small number of bacteria. Comfortable sensation in nylon socks and polyester+nylon+linen socks was significantly uncomfortable. The way socks finished and air permeability of .jocks affected theirs hygienic property, while fiber type of them affected comfortablene, is. Bacteria identified were Staphylo coccus aureus, S. au rice larir, S. cahn ii, S. ep ids midis, S. haemo Iyticus, S. h am in 2's. S.fapraphyticus, S. warnery, 1 cinetobater calcoaceticus bio. anitratus, p.reudomonas mendocina, p. paucimobilis, Flavimonas Q ryzihabitans (CDC Group VE-2), and Xanthomanas maltophina. Fungi isolated were Spicaria sp., Thrichoderma sp., Fusarium sp., Aspergillus sp., Epicoccum sp., Cladosporium sp., and Penicillium sp..

• Journal of Biomedical Engineering Research
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• v.23 no.2
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• pp.119-130
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• 2002

The nonlinear finite element program has been developed to analyze the design performance of an artificial hip prosthesis and long term behavior of a treated femur with stems made of composite material after cementless total hip arthroplasty(THA). The authors developed the three dimentional FEM models of femoral bone with designed composite stem which was taken with elliptic cross section of 816 brick elements under hip contact load and muscle farce in simulating single leg stand. Using the program, density changes, stress distributions and micromotions of the material femoral bone were evaluated by changing fiber orientation of stems for selected manufacturing method such as plate cut and bend mold. The results showed that the composite materials such as AS4/PEEK and T300/976 gave less bone resorption than the metallic material such as cobalt chrome alloy, titanium alloy and stainless steal. It was found that increasing the long term stability of the prosthesis in the femur could be obtained by selecting the appropriate ply orientation and stacking sequence of composite.

• Membrane Journal
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• v.28 no.1
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• pp.21-30
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• 2018

In this study, homogeneous and defect-free ceramic ultrafiltration membranes were fabricated by using the sol-gel method. A boehmite sol was synthesized and coated onto the surface of alumina hollow fiber microfiltration membranes. The effect of sol viscosity and surface tension on the coating layer homogeneity and thickness was investigated. The optimum coating repetition using pristine sol was determined to be 3 times, as the samples coated more than 4 times showed delamination. Fixing the coating repetition to 3 times, the effect of sintering temperature was also studied in this work. The samples sintered at $1000^{\circ}C$ exhibited the highest pure water permeability with the molecular weight cut-off (MWCO) of approximately 51 kDa (10 nm dextran), and the samples sintered at 600, $800^{\circ}C$ displayed the MWCO of 12 kDa (5 nm dextran). The ultrafiltration membranes prepared in this work showed competitive performance compared to the reported ceramic ultrafiltration membranes.