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용융방사에 있어서 연신공명과 섬유 불균제도에 관한 연구(I) -폴리프로필렌의 방사조건이 섬유 불균제도에 미치는 영향-
정호규,김상용 한국섬유공학회 1995 한국섬유공학회지 Vol.32 No.3
The effects of spinning conditions on the filament irregularity and the periodicity of irregularity caused by draw resonance in the melt spinning of polypropylene were investigated. The filament irregularity increased with the increase of draw ratio at both isothermal and nonisothermal conditions, but the slope of irregularity versus draw ratio and the period al nonisothermal conditions were smaller than those at isothermal condition. In both isothermal and nonisothermal conditions, the filament irregularity increased with the flow rate, but decreased with spinning temperature. In the isothermal conditions, filament irregularity increased with the spin length, but decreased in nonisothermal condition. When the draw ratio was increased, the amplitude of the fiber diameter variation increased, but the frequency of oscillation was unchanged. This results illustrated that the draw resonance is a hydrodynamic instability The period of irregularity caused by draw resonance increased with spin length, and decreased with flow rate, but spinning temperature had no effect on the period.
방사 불안정성과 섬유 균제도에 관한 연구-폴리프로필렌의 용응방사에 있어서 연신총명과 섬유 불균제도의 관계-
정호규,김상용 한국섬유공학회 1995 한국섬유공학회지 Vol.32 No.2
The relation between the draw resonance and filament irregularity in the melt spinning of polypropylene was studied. The derivation of equation between draw resonance and filament irregularity, approximation of the equation and its limiting values were made and the experimental verification of the theory and its simplification, and the shape of the fiber diameler variation caused by draw resonance were investigated. A photo-sensor was used for on-line measurements of the fiber diameter variations in the melt spinning process and the period of draw resonance was obtained by courier transfermation. By the use of courier series, a series equation expressing the irregularity CV(%) in terms of Fourier coefficients and Dmax/Dmin value, was derived. After comparing the actual CV(%) with the calculated CV(%) at various Fourier integer n values, it was found that the equation could be simplified by omitting courier coefficient subscript values neater than 6. The effect of spinning variables on the filament irregularity of polypropylene monofilaments were investigated by carrying out the melt spinning at both isothermal and nonisothermal conditions. The results showed that the filament irregularity CV(%) increased with the Dmax/Dmin values. The filament irregularity increased with the draw ratio at both isothermal and nonisothermal conditions, and the shape of fiber diameter variation was changed from quasi-sinusoidal waveform to a pulse train. Draw resonance was affiected by spinning conditions, but at the fixed draw resonance values the constant irregularity is obtained, independent of the spinning conditions. The fiber diameter variation showed a transition from quasi-sinu-soidal waveform to a pulse train at a Dmax/Dmin value of approximately 3. From the analysis of frequency spectrum obtained from courier transformation, the contribution of the 2nd and 3rd resonant frequency to the total fiber diameter variation increased with the draw ratio.
정호규,Takeshi Kikutani 한국섬유공학회 1999 한국섬유공학회지 Vol.36 No.11
High-speed melt spinning of single and bicomponent fibers of poly ethylene terephthalate (PET) and nylon 6 was carried out. The structure changes in the individual components of the single and bicomponent fibers with take-up velocity were investigated by birefringence, wide-angle x-ray diffraction, and DSC. The orientation crystallization of PET in the bicomponent fiber was enhanced in comparison with the pure PET fiber, while the orientation of the PET component increased with decreasing the PET content. On the other hand, the orientation of the nylon 6 component was lower than that of the corresponding single component fiber. The cold crystallization temperature of PET in the bicomponent fiber was lower than that of the pure PET fiber. It was also lowered with decreasing PET content. The crystal formation of PET in the bicomponent fiber occurred at a lower take-up velocity than that of the pure PET fiber. In high speed spinning, neck-like deformation was also observed in the bicomponent spinning. The neck-like deformation of PET occurred at a position closer to the spinneret than that of nylon 6, mean-while the position of the neck-like deformation of the 1:3 bicomponent fiber was observed at a position closer to the spinneret than that of the pure PET fiber.
젤방상, 열연신 방법에 의한 고강력, 고탄성률 섬유고분자재료의 개발
정호규 한국유변학회 1995 Korea-Australia rheology journal Vol.7 No.2
농도 5w%의 초고분자량 폴리에틸렌(분자량:1.5$\times$106)을 상온으로 냉각시켜 벨을 만 들고 이를 방사하여 섬유를 제조하였다. 이때 방사구를 나온 섬유를 $0^{\circ}C$에서 9$0^{\circ}C$까지의 냉 각조를 통과시켜 젤화/결정화 온도를 다르게 하였다. 최대 연신비는 온도가 $0^{\circ}C$에서 7$0^{\circ}C$까 지 증가함에 따라서 증가하고 9$0^{\circ}C$에서 젤화/결정화시킨 섬유의 경우에는 감소한다. 시차주 사열분석, 배향, 인자, 복굴절률, 절단강도와 탄성률을 측정하여 섬유의 물성에 대해 고찰하 였다. 연신비의 증가에 따른 결정화도, 용융 온도, 복굴절률의 증가는 높은 온도에서 젤화/ 결정화시킨 섬유인 경우가 더 뚜렷했다.
정호규,서보석 충북대학교 컴퓨터정보통신연구소 2014 컴퓨터정보통신연구 Vol.22 No.1
In this paper, we review the noncontact measurement method of resistance using light excitation, and propose an improved measurement method. The methods to measure the resistivity or sheet resistance of the semiconductor wafer or sheet materials can be categorized into contact and noncontact methods. While the contact method gives an accurate measurement, it has some disadvantages caused by contact measurement which may causes impairment of the sample or takes a long time to measure. In noncontact measurement instrument, leakage current is used to measure the sheet resistance generated by light excitation or magnetic excitation. In conventional methods, a point type excitation is generally used, where the leakage current decreases as the inverse of the square of the distance. The measured voltage is very small and the measurement error may be high. In this paper, we propose a line type light excitation where the leakage current decreases as the inverse of the distance. The measured voltage is relatively high and the measurement error can be reduced. We verify the proposed method by measuring the resistivity using the manufactured measurement prototype.
Simplified Stress-Strain Relations of Multi-ply Cords
김상용,정호규,조재환,Kim, Sang-Yong,Jeong, Ho-Gyu,Jo, Jae-Hwan The Korean Fiber Society 1986 한국섬유공학회지 Vol.23 No.5
Simplified tensile stress-strain relation of textile cords was derived and discussed with Riding's experimental results. Theoretical equations for two-, three-and seven-ply cords are developed under the consideration of different geometrical packing. The tensile stress-strain relation of cord is expressed in terms of "Cord Factor." As cord twist and cord strain increase, the deviation between theoretical and experimental values increases for the two and three-ply cords. In case of seven-ply cord, the agreement between the calculated and experimental is very good compared with the other two cord structures.