• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 1999년도 추계학술발표대회 논문집
• /
• pp.211-214
• /
• 1999

The stress distribution around the cutout of composite cylindrical shells with a circular or elliptical reinforced cutout subjected to axial compression or tension is studied by asymptotic method. Analytical solutions used a Donnell type orthotropic shell theory are presented by the defined stress concentration factor and are compared to experimental results. The experiment used the universal testing machine (UTM), strain gage and fixtures designed/manufactured for axial tension test of a cylindrical shell is carried and the composite material used in the experiment is plain weave glass fiber reinforced plastic (GFRP).

• 한국초전도ㆍ저온공학회논문지
• /
• 제5권2호
• /
• pp.51-57
• /
• 2003

This paper proposes a new oscillating flow model of the pressure drop through the regenerator under pulsating pressure. In this oscillating flow model. pressure drop is expressed by the amplitude and the phase angle with respect to the inlet mass flow rate. In order to generalize the oscillating flow model. non-dimensional parameters, which are Reynolds number, Valensi number, gas domain length ratio, oscillating flow friction factor and phase angle of pressure drop, are derived from the capillary tube model of the regenerator. Correlations for the oscillating flow friction factor and the phase angle are obtained from the experiments for the twill-square screen regenerators under various operating frequencies and inlet mass flow rates. The oscillating friction factor is a function of the Reynolds number alone and the phase angle of pressure drop is a function of the Valensi number and the gas domain length ratio. Experiment is also performed to examine the effect of the weave style of screen. Experimental data demonstrate the superiority of the oscillating flow model over the previous steady flow model.

• 한국의류학회지
• /
• 제23권6호
• /
• pp.820-828
• /
• 1999

The purpose of this study was to investigate the changes of pore area and water vapour transport by the changes of moisture regain and fabric structure of wool fabrics, As specimens 4 worsted wool fabrics were used. The pore area were measured by image analysis method and dinamic vapour transport and water reisitance was determined by clothing-environment-body modelling system. The pore area was changed by the moisture regain of wool fabrics. The change of pore area was influenced by the yarn twist thread count and cover factor and the weave type. The water vapour transport was changed by the moisture regain. The change of water vapour transport was influenced by the change of pore aree which was determined by image analysis.

• 대한가정학회지
• /
• 제49권1호
• /
• pp.121-133
• /
• 2011

This research was designed to compare the subjective evaluation of texture image and preference between offline and online by structural characteristics of women' jacket fabrics for spring and summer. 78 participants evaluated the sensibility image and preference of various fabrics. The data were analysed by factor analysis, t-test, Pearson's productive correlation, regression, and multi dimensional scale. The results were as follows: Sensibility image factors of women' jacket fabrics were 'classic' 'sophisticated' 'natural' 'characteristic' and 'practical'. Between offline and online, sensibility images showed no differences. In sensibility images, 'classic'-'sophisticated', 'natural'-'practical', and 'practical'-'characteristic' images showed significant correlation. By analyzing the contribution of fabric structure on sensibility images, density affected on the 'classic' image offline and online. By the results of regression analysis, thickness, density and weave affected on the tactile preference. In sensibility images, 'classic', 'sophisticated' 'characteristic' images were the influencing factor. 'Sophisticated', 'natural', 'characteristic' and 'practical' images affected on the purchase preference.

• Tissue Engineering and Regenerative Medicine
• /
• 제15권6호
• /
• pp.711-719
• /
• 2018

BACKGROUND: Collagen organization within tissues has a critical role in wound regeneration. Collagen fibril diameter, arrangements and maturity between connective tissue growth factor (CTGF) small interfering RNA (siRNA) and mismatch scrambled siRNA-treated wound were compared to evaluate the efficacy of CTGF siRNA as a future implement for scar preventive medicine. METHODS: Nanocomplexes of CTGF small interfering RNA (CTGF siRNA) with cell penetrating peptides (KALA and $MPG^{{\Delta}NLS}$) were formulated and their effects on CTGF downregulation, collagen fibril diameter and arrangement were investigated. Various ratios of CTGF siRNA and peptide complexes were prepared and down-regulation were evaluated by immunoblot analysis. Control and CTGF siRNA modified cells-populated collagen lattices were prepared and rates of contraction measured. Collagen organization in rabbit ear 8 mm biopsy punch wound at 1 day to 8 wks post injury time were investigated by transmission electron microscopy and histology was investigated with Olympus System and TS-Auto software. CONCLUSION: CTGF expression was down-regulated to 40% of control by CTGF siRNA/KALA (1:24) complexes (p<0.01) and collagen lattice contraction was inhibited. However, down-regulated of CTGF by CTGF $siRNA/MPG^{{\Delta}NLS}$ complexes was not statistically significant. CTGF KALA-treated wound appeared with well formed-basket weave pattern of collagen fibrils with mean diameter of $128{\pm}22nm$ (n = 821). Mismatch siRNA/KALA-treated wound showed a high frequency of parallel small diameter fibrils (mean $90{\pm}20nm$, n = 563). CONCLUSION: Controlling over-expression of CTGF by peptide-mediated siRNA delivery could improve the collagen orientation and tissue remodeling in full thickness rabbit ear wound.

• 한국의류학회지
• /
• 제39권5호
• /
• pp.778-788
• /
• 2015

This study evaluated the characteristics and sensibility of work clothes materials developed that took into account the work environment of major industrial settings, for which a selection was made according to spring/autumn use and winter use. The physical properties of the existing and test weaving of the work clothes materials were compared after the test weaving of work clothes materials through material design, which altered the yarn count, composition, weave and density of material. To evaluate sensibility of work clothes materials subjectively, seven ranks' semantic differential scale questions were developed with polar adjective pairs. The test weaving of work clothes materials showed improved performance (such as tensile strength, dimensional change, water vapor permeability, and color fastness) compared to the existing materials. The common factor analysis indicated that the explanatory power of the cumulative variance for the spring/autumn use and winter use was 71.19% and 69.53%, respectively.

• Macromolecular Research
• /
• 제11권2호
• /
• pp.98-103
• /
• 2003

The mechanical properties and failure mechanisms of through-the-thickness stitched plain weave glass fabric/polyurethane foam/epoxy composites were studied. Hybrid composites were fabricated using resin infusion process (RIP). Stitched sandwich composite increased drastically the flexural properties as compared with the unstitched fabrics. The breaking of stitching yarns was observed during the flexural test and this failure mode yielded relatively high flexural properties. Composites with stitched sandwich structure improved the mechanical properties with increasing the number of stitching yarns. From this study, it was concluded that proper combination of stitching density and types of stitching fiber is important factor for through-the-thickness stitched composite panels.

• 복식문화연구
• /
• 제14권6호
• /
• pp.1015-1026
• /
• 2006

The purpose of the study were to find out (1) the effect of motives on perceiver's image perception on ramie fabrics, and perceiver's trait, age and gender on sensory image evaluation of ramie fabrics. The research was a quasi experiment and experimental materials developed for the study were a set of material stimuli and semantic differential scales to measure sensory image of the stimuli, an aesthetic value scale. the independent design was motif design techniques(Plain Weave, burnt-out, embroidery, stripe, check). The subjects were 421 adults in Daejeon and Seachun. The results was as follows: The factor analysis of semantic differential scales for the ramie materials emerged 4 different image dimensions: attractiveness, hand, elegance, weight). The five design techniques showed significantly different image affects on some selective dimensions. The burn-out design gave the most attractive image, the embroidery design gave the softest image and plain weaved fabric presented the lightest hand image. Consumer's aesthetic values, gender and age tended to affect sensory image evaluation of ramie materials. On conclusion the result revealed that design strategy for the ramie material, design development though motives will be an essential process. and for material design pursued design image and target consumer's trait should be carefully considered.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2004년도 추계학술대회논문집
• /
• pp.928-933
• /
• 2004

The vibration characteristic is a primary design factor. The cylindrical shells are used as a primary components of complex structure. also, The cylindrical shells have oblique angle. In this study, The vibrational characteristics of steel and plain wave GFRP cylindrical shell with an oblique end are given by experimental and finite element method. To be find characteristic of the oblique end, the mass of the cylindrical shell is maintained. Natural frequency and mode shapes of isotropic and plain weave composite shells are obtained by modal test. The results are compared with those of the finite element method. The simply supported boundary conditions with bolts along the circumferential direction of the GFRP shell are well achieved. Also, The clamped boundary conditions is applied to the steel specimen. Those are shown to agree well with the analytical results and finite element analysis results.

• Archives of Pharmacal Research
• /
• 제28권11호
• /
• pp.1311-1316
• /
• 2005

To better define the relationship between dermal regeneration and wound contraction and scar formation, the effects of epidermal growth factor (EGF) loaded in collagen sponge matrix on the fibroblast cell proliferation rate and the dermal mechanical strength were investigated. Collagen sponges with acid-soluble fraction of pig skin were prepared and incorporated with EGF at 0, 4, and 8 $\mu$g/1.7 $cm^{2}$. Dermal fibroblasts were cultured to 80$\%$ confluence using DMEM, treated with the samples submerged, and the cell viability was estimated using MTT assay. A deep, $2^{nd}$ degree- burn of diameter 1 cm was prepared on the rabbit ear and the tested dressings were applied twice during the 15-day, post burn period. The processes of re-epithelialization and dermal regeneration were investigated until the complete wound closure day and histological analysis was performed with H-E staining. EGF increased the fibroblast cell proliferation rate. The histology showed well developed, weave-like collagen bundles and fibroblasts in EGF-treated wounds while open wounds showed irregular collagen bundles and impaired fibroblast growth. The breaking strength (944.1 $\pm$ 35.6 vs. 411.5 $\pm$ 57.0 Fmax, $gmm^{-2}$) and skin resilience (11.3 $\pm$ 1.4 vs. 6.5 $\pm$ 0.6 mJ/$mm^{2}$) were significantly increased with EGF­treated wounds as compared with open wounds, suggesting that EGF enhanced the dermal matrix formation and improved the wound mechanical strength. In conclusion, EGF-improved dermal matrix formation is related with a lower wound contraction rate. The impaired dermal regeneration observed in the open wounds could contribute to the formation of wound contraction and scar tissue development. An extraneous supply of EGF in the collagen dressing on deep, $2^{nd}$ degree-burns enhanced the dermal matrix formation.