• International Journal of Safety
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• v.4 no.2
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• pp.6-11
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• 2005

The goals of the paper are to understand the impact damage behavior and identify the effect of surface protective materials on impact resistance in filament wound composite pressure vessels. For these, a series of low velocity impact tests was performed on specimens cutting from the full scale pressure vessel by the instrumented impact testing machine. The specimens are classified into two types, which are with and without surface protective material. The visualization for impact damage by two different impactors is made by metallurgical microscope. Based on the impact force history and damage, the impact resistance parameters were employed,rod its validity in identifying the damage resistance of filament wound composite pressure vessel was reviewed. As the results, the impact resistance of the filament wound composites and its dependency on the surface protective material were evaluated quantitatively

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.378-379
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• 2008

Recently, composite hollow bushings have been increasingly employed mainly from the various characteristics. Composite bushings are superior to porcelain bushings in several respects, including lighter weight, better anti-pollution and anti-explosion properties, and easer manufacturing. Filament wound GRP tubes which have various winding angle were manufactured by using a filament winding machine. This paper will show some design issues and winding condition for composite bushing. And, results show that the winding condition of composite GRP tubes can be used to improved their bending strength and pressure, For bending and pressure tested, tubes with the hybrid winding pattern show higher strength than those of unit winding pattern. Also, the influence of absorption was evaluated through such as measurement of the dye penetration test and water diffusion test, also aspects of surface state using scanning electron microscopy.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.3-9
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• 2006

Among many fabrication methods of composite materials, filament winding is the most effective method for fabricating axis-symmetric structures such as pressure tanks and pipes. Filament wound pressure tanks are under high internal pressure during the operation and it has the complexity in damage mechanisms and failure modes. Fiber optic sensors, especially FBG sensors can be easily embedded into the composite structures contrary to conventional electric strain gages (ESGs). In addition, many FBG sensors can be multiplexed in single optical fiber using wavelength division multiplexing (WDM) techniques. In this paper, we fabricated several filament wound pressure tanks with embedded FBG sensors and conducted some kinds of experiments such as an impact test, a bending test, and a thermal cycling test. From the experimental results, it was successfully demonstrated that FBG sensors are very appropriate to composite structures fabricated by filament winding process even though they are embedded into composites by multiplexing.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1259-1264
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• 2008

This paper presents an accelerated life test for burn out of tungsten filament of automotive halogen lamp. There are many failure modes and failure factors that associated with tungsten filament. But in this explain the dominant failure mode of tungsten filament is the bumout of the filament failure. At first, over voltage, high temperature, inrush current and vibration are selected as stress factors by using of two stage Quality Function Deploymeng(QFD). And we planed accelerated life test that has one factor(voltage) and three levels. By experiment it has absorbed that over voltage has an effect on the life of halogen lamp. Using ALTA programs, we estimated the common shpae parament of Weibull distribution, life-stress relationship and $B_{100p}$ life.

• Journal of the Korean Ceramic Society
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• v.26 no.4
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• pp.550-558
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• 1989

Polycrystalline diamond films have been deposited on Si wafer Ly hot W filament CVD method using CH4H2 mixtures. The effects of surface pretreatment, W filament temperature, CH4 volume fraction, and addition of water vapor on the growth rate and morphology of the films were investigated. Surface pretretment was essential for depositing a continuous diamond film. Raising the filament temperature resulted in an increased growth rate and a better crystal quality of the film. As the methane content is varied from 0.5% to 5%, well-faceted crystals gradually transformed into spherical particles of non-diamond phase with a simultaneous increase in the growth rate. Addition of water vapor markedly improved the crystallinity to produce crystalline particles even with 5% methane mixture.

• Journal of the Korean Professional Engineers Association
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• v.9 no.1
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• pp.35-39
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• 1976

Possible methods of protection of non cellulosic fibers, particularly nylon filament yarn, from the damaging effects of light are discussed. Manganese acetate, cupricacetate, G1-06-196 and sodium phosphate are used as a light stabilizer for nylon filament yarn. The light stability of filament containing different weight of TiO$_2$ is increased as the following order: Bright>Semi-Dull>Full-Dull The protection effect against light according to the present of the light stabilizer in filament increased in the following order: Manganese acetate> Cupric acid> G1-06-196> Sodium phosphate Manganese acetate is shown to be the most effecting salt for protecting nylon against light. 15 ppm of the salt is shown to be effective enough for protecting nylon filament yarn against light.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.17-20
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• 2005

In-situ structural health monitoring of filament wound pressure tanks were conducted during water-pressurizing test using embedded fiber Bragg grating (FBG) sensors. We need to monitor inner strains during working in order to verify the health condition of pressure tanks more accurately because finite element analyses on filament wound pressure tanks usually show large differences between inner and outer strains. Fiber optic sensors, especially FBG sensors can be easily embedded into the composite structures contrary to conventional electric strain gages (ESGs). In addition, many FBG sensors can be multiplexed in single optical fiber using wavelength division multiplexing (WDM) techniques. We fabricated a standard testing and evaluation bottle (STEB) with embedded FBG sensors and performed a water-pressurizing test. In order to increase the survivability of embedded FBG sensors, we suggested a revised fabrication process for embedding FBG sensors into a filament wound pressure tank, which includes a new protecting technique of sensor heads, the grating parts. From the experimental results, it was demonstrated that FBG sensors can be successfully adapted to filament wound pressure tanks for their structural health monitoring by embedding.

• International Journal of Industrial Entomology and Biomaterials
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• v.14 no.1
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• pp.23-32
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• 2007

The nature of genetic variation and diversity among the 65 multivoltine silkworm genotypes was evaluated for 16 post cocoon characters. The components of genetic variation revealed higher PCV (60.487%) and GCV (44.56%) for evenness (variation 1) followed by cohesion (PCV=55.38%, GCV=40.36%) and non-broken filament length (PCV=32.05%, GCV=31.28%). The higher heritability ($h^2$ in broad sense) was observed for boil-off loss (95.6%) followed by non-broken filament length (95.22%). The both genotypic and phenotypic correlation indicated significant positive correlation of filament length with non-broken filament length, silk recovery, raw silk, neatness, and low neatness; and negative correlation with denier, renditta and silk waste. The principal component analysis (PCA) revealed 75.381 % of total variance from the five principal components extracted. On the basis of Mahalonobis' $D^2$ values (Ward's minimum variance), the sixty-five multivoltine silkworm genotypes were classified in to 9 clusters with substantial inter and intra cluster distances. Number of genotypes included in different clusters varied from 3 to 17. The results indicated that the optimum distance obtained in cluster VII (15.059) along with higher cluster mean values especially for filament length, non broken filament length, renditta, silk recovery, silk waste, and raw silk emphasized the utilization of these genotypes in the conventional silkworm breeding programme for improvement of multivoltine silk fibre quality. The possibility of exploiting genetic variation in post cocoon traits for efficient breeding programme is discussed.

• Journal of Sericultural and Entomological Science
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• v.40 no.2
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• pp.150-157
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• 1998

This study was carried out to define the effects of anti-juvenile hormone analogue(AJH) treatment at different silkworm larval stages on some silk filament properties. It was revealed that the treatments at the 1st and 2nd days of the 3rd instar as well as the 1st day of the 4th instar resulted to trimolters induction without lethal effect. The trimolters induced by treatment at the 1st day of the 4th instar showed the shortest larval duration and the lowest single cocoon weight, cocoon shell ratio, cocoon size, single filament length and denier of filament compared with those of the control, while the trimolters induced by the 3rd-instar treatment showed intermediate values. All treatments showed no significant differences from the aspect fo degumming ratio, elongation rate and crystallinity index of fibroin. However the silk filament obtained from the treatment at the 1st day of the 4th instar showed the highest tenacity which was revealed to be related to the better uniformity of filament by the means of microscopic photographing. FT-IR spectroscopy of the silk fibroin showed a sharp and strong peak at the position of 794.72 cm-1 in all AJH-treated samples regardless of trimolters induction, which was absent in control.

• Applied Microscopy
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• v.21 no.1
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• pp.46-62
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• 1991

The intermediate filament is one of the most important constituents of the intracytoplasmic cytoskeleton microtubule, actin, myosin and intermediate filament. It is composed of keratin, desmin, vimentin, neurofilament and glial filament, and has important role as a cellular marker, epithelial or mesenchymal origin. So it will be important to differentiated from some poorly or undifferentiated neoplasm to provide adequate therapeutic modalities. This study was performed by using immunohistochemical staining and electron microscopic observation to find out intermediate filaments of epithelial and non-epithelial tumor cells evaluate the degree of differentiation in tumors and therefore to provide some diagnostic and therapeutic modalities. The materials consisted of 83 epithelial and non-epithelial elements bearing 23 normal control, 28 epithelial tumors, and 32 non-epithelial tumors, that are resected for definite treatment at Chosun University Hospital from June, 1988 to June, 1990. Immunohistochemical stain for keratin, desmin and vimentin, and electron microscopic study were performed in all cases. The results obtained were as follows. 1. Immunohistochemical stain for intermediate filament were very useful diagnostic aid for differentiated epithelial tumor to non-epithelial tumor in diagnostic neoplasia. 2. In the electron microscopic finding, the size of intermediate filaments were possible differentiated to cell components of epithelial tumor and non-epithelial tumors.