• Journal of The Korean Astronomical Society
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• v.42 no.1
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• pp.9-15
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• 2009

A necessary condition for the formation of a filament is magnetic helicity. In the present paper we seek the origin of magnetic helicity of intermediate filaments. We observed the formation of a sinistral filament at the boundary of a decaying active region using full-disk $H_{\alpha}$ images obtained from Bi Bear Solar Observatory. We have measured the rate of helicity injection during the formation of the filament using full-disk 96 minute-cadence magnetograms taken by SOHO MDI. As a result we found that 1) no significant helicity was injected around the region (polarity inversion line; PIL) of filament formation and 2) negative helicity was injected in the decaying active region. The negative sign of the injected helicity was opposite to that of the filament helicity. On the other hand, at earlier times when the associated active region emerged and grew, positive helicity was intensively injected. Our results suggest that the magnetic helicity of the intermediate filament may have originated from the helicity accumulated during the period of the growth of its associated active region.

• Journal of Sericultural and Entomological Science
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• v.14 no.1
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• pp.43-47
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• 1972

The tensile properties of cocoon filament obtained from the dried cocoon were studied by deniroscope and tensilon with special attachments. The strength and dried elongation at break feint with dry and swollen samples were observed. The apparent young's modulus was also calculated with the dry samples. The results obtained are as follows. 1) The breaking strength of dry and swollen samples decreased in parallel with denier decreasing ratio in the whole length of a cocoon filament. 2) Tensile strength of inner-layer filament, when treated at the temperature of 95$^{\circ}C$ for 15 min., was 37 per cent of outer-layer filament. 3) By swelling treatment, the breaking strength of the filament was decreased but the elongation was increased. 4) Apparent young's modulus and tensile strength per denier of inner-layer filament were higher than those of the rest cocoon layer.

• Fashion & Textile Research Journal
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• v.16 no.2
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• pp.326-332
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• 2014

To develop cool touch feeling fabrics for summer clothing material, it was manufactured several compositions of woven fabrics, having rayon multi-filament yarn (non-twisted) as warp and various kinds of yarn, such as viscose rayon multi-filament yarn (twisted), tencel$^{(R)}$ spun yarn, PET high absorbance quick dry filament yarn, and PET based rayon-like yarn, as weft. After preparing the fabrics, basic properties of the fabrics were investigated, such as air-permeability, tensile strength, absorption rate, drying rate, etc. Also, surface warm / cool sensations of the woven fabrics were assessed by Qmax Warm / Cool Touch Tester. It was observed that the fabrics composed of viscose rayon multi-filament yarn (warp) and PET high absorbance quick dry filament yarn (weft) showed excellent surface cool touch sensation-the highest Qmax value. This is because the fabric having flat shaped PET high absorbance quick dry filament shows the largest contact area with Qmax measuring plate. And, the fabric also showed superior high absorbance and quick dry property as expected. In addition, we treated phase change material (PCM) on the surface of the fabric composed of viscose rayon multi-filament yarn (warp) and PET high absorbance quick dry filament yarn(weft) to improve the cool touch feeling. However, the surface cool touch feeling was impaired by resin treated with PCM during the finishing process.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.44.4-45
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• 2015

We investigate the properties of galaxies belonging to the filaments in cosmic void regions, using the void catalogue constructed by Pan et al. (2012) from the SDSS DR7. To identify galaxy filaments within a void, voids with 30 or more galaxies are selected as a sample. We identify 3067 filaments in 1050 voids by applying the filament finding algorithm based on minimal spanning tree and reducing processes to spatial distribution of the void galaxies. We study the correlations between galaxy properties and the specific size of filament which quantifies the degree of the filament straightness. For example, the average magnitude and the magnitude of the faintest galaxy in filament decrease as the straightness of the filament increases. We also find that the correlations become stronger in rich filaments than in poor ones with fewer member galaxies. We discuss a physical explanation to our findings and their cosmological implications.

• Applied Science and Convergence Technology
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• v.24 no.5
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• pp.142-150
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• 2015

A failure analysis of tungsten filaments used in quadrupole mass spectrometer for plasma process monitoring was carried by using SEM and EDS. Failed at high temperature, filaments showed two kinds of failure modes. The one is that diameter of filament became thinner gradually and finally snapped. The other is that filament abruptly snapped almost at a right angle. The EDS analysis showed Fe and C, including W and Fe, on the surface of failed filament. when failed filaments were treated with plasma in mixture of Ar and $CF_4$, the amount of Fe and C decreased. The failure analysis of filament showed that the cause of filament failure is thermal evaporation and grain growth of tungsten at high temperature.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.273-276
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• 2003

High-temperature superconduction materials(Bi2223) possess electrical/electronic and magnetic properties. Because high-temperature superconduction materials is a ceramic powder, that can not be produced singlehandedly. So Ag sheathed Bi-2223 wire was produced by drawing process using powder-in-tube(PIT) method. This superconductor has many difficulties to produce. The main difficulty is that the mechanical properties of the ceramic powder are very different from those of the Ag sheath. Bi2223 high-temperature superconductivity have a single filament drawing process, and multi-filament drawing process. This study analysed multi-filament drawing process by FEM, a defects during multi-filament drawing was studied by FEM.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.199-210
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• 2000

복합재료의 성형 공정 중 하나인 Filament Winding 공정에 열가소성 기지재료인 폴리프로필렌(Polypropylene)과 강화섬유인 유리섬유로 이루어진 Commingled Yarn 을 이용한 연구를 수행하였다. 함침 과정을 해석하기 위한 계산모델을 제시하였다. 그리고 위의 모델링을 해석하는 데 필요한 복합재료 내의 온도 분포를 수치해석을 통해 계산하였고 실험을 통해 이를 검증하였다. 온도계산 결과를 함침도 예측에 이용하였다. 모델링을 통해 Filament Winding 공정의 주요 공정 변수를 찾아내었고 제시한 모델을 검증하기 위해 직접 Filament Winding 실험 장치를 제작하여 제품을 생산하고 모델과 비교하였다. 제작된 시편으로부터 함침도를 계산하는 방법을 제시하였다. 그 결과 함침도에 관해서 실험 결과가 모델과 그 경향이 뚜렷이 일치함을 확인하였다.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.179-182
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• 2003

This research aims to establish an optimal design method of filament wound structures. So far, most design and manufacturing of filament wound structures have been based on manufacturing experiences, and there is no established design rule. In this research, possible winding patterns considering the windability and the slippage between fiber and mandrel surface were calculated using the semi-geodesic path algorithm. In addition, finite element analyses using a commercial code, ABAQUS, were performed to predict the behavior of filament wound structures. On the basis of the semi-geodesic path algorithm and the finite element analysis method, filament wound structures were designed using the genetic algorithm.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.6-8
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• 2000

The critical current density, Jc, of superconductor tape significantly depends on microstructural evolution during mechanical deformation. In this study, we fabricated Bi-2223 superconductor tape by PIT technique, and investigated mechanical properties of mono- and 61-filamentary tapes and their joined tapes. The strength of mono-filament tape was higher than those of 61-filament tape was higher than those of 61-filament tape, respectively. On the other hand, elongation of mono-filament tape, respectively. On the other hand, elongation of mono-filament tape was lower than 61 filament tape. The joined tapes shows lower strength and irreversible strain than those of unjoined tapes. The reduced strength and irreversible strain for joined tape is probably related to the induced damages such as irregular interface and Ag-instrusion in the transition region which acts as a stress concentration.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.263-266
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• 1987

Generally an incandescent lamp is made in the bulb with a horizontal position filament. In this paper the position of filament was changed Into a vortical position. When the position of filament is changed into a vertical position, efficacy is increased and color rendering is somewhat improved. In this subject the heat loss by a filling gas is important. The heat loss by a filling gas was calculated theoretically. The results in an Incandescent lamp experiment can be analyzed through the heat loss by a filling gas. As a filling gas the mixture of argon and nitrogen is used. The variation of lamp characteristics by the shape of filament rill be considered. The change by filament position to a vortical position is required in the field of power consumption saving of lighting system.