초기조건으로 직전위치에 대한 위사간격의 자유응답 - 이론적 모델과 시뮬레이션-

허유,류운영,우제린,Huh, You,Ryu, Woon-Young,Woo, Jae-Lin 한국섬유공학회 1992 한국섬유공학회지 Vol.29 No.9

The quality of woven fabrics is deeply affected by the regularity of warp and weft density, which is one of the fundarnental fabric pararneters determining the physical properties of fabrics. In particular the regularity of weft density can be easily destroyed in a transient or unstable processing state, for example: when weaving process is interrupted by a disturbance or in the case of article change. In most cases, a reruning of the weaving machine leaves a fabric fault in the form of streaks which caused by the irregularity of weft density. This fault is called "stop mark" and is nowadays one of the most frequently occurring errors in fabrics. In this study, it was tried to analyze the mechanism how a stop mark takes place and to obtain a theoretical model. During modelling, it was proposed that the latest pickspacing can be affected by the beating motion which build up a new pickspacing as a result of new weft insertion. The mathematical model has shown a nonlinear simultaneous difference equation system which consists of equations about the pickspacing and clothfell position. The results of simulation revealed that forward movement of dothfell position has a sensitive effect on occurrence of dense weft streaks. The backward movement of clothfell position, however, brought about a broad and thick weft streaks.t streaks.

제직시스템에서의 속도변화에 대한 위사밀도의 동적 응답 (I)

허유,류운영,우제린,Huh, You,Ryu, Woon-Young,Woo, Jae-Lin 한국섬유공학회 1991 한국섬유공학회지 Vol.28 No.11

Factors affecting fabric quality are yarn, weaving machine and men. Among them the weaving machine and men can be controlled in the weaving Process. Most of fabric defects result from the yarn, the weak points of which cause the discontinuities in the machine operation responsible for the endbreakages. The interruption in production can be reduced by an optimal operation of weaving machines, but the cause of endbreakages can not be completely eliminated. The places where the machine stopped and restarted leave streaks on the fabrics, which result in the fabric defects. These defects, so called stop marks, lead to the irregularity of weft density This paper deals with relationship between the change in weft density and the weaving interruption. The weft density change, the stop mark, was measured in terms of pickspacing and the mode of weaving interruption determined by applying different forms of speed variations. The results show that the weft density change is mostly influenced by the rate of speed variation. The initial loading on the warp yarns is independent of the total weft density change, but it is responsible for the distribution of the weft density irregularity.

링 방적사의 섬유 이주거동에 관한 연구(II) -이주거동에 의한 구조해석-

허유,김영률,류운영,Huh, You,Kim, Young-Ryul,Ryu, Woon-Young 한국섬유공학회 2004 한국섬유공학회지 Vol.41 No.4

Ring spun yam is the most widely used yarn type, especially for quality staple yarns. But the exact structure of the ring spun yarn is not known and the structure is explained only qualitatively. This study suggests a method for determining the structural characteristics quantitatively, defining a packing density (unction and a migration factor. The results show that ring spun yarn has a maximum packing density at around 2/3 of the yarn radius. The fibers in the yarn center are arranged parallel or with a small angle to the yarn axis, which is different from what has been known to us. The migration factor of a ring spun yarn ranges from 0.76 to 1.29. depending on the twist level that affects the fiber migration positively.

제직공정에서 제직 시동 조건이 품질에 미치는 영향

허유,이상택,류운영,우제린,Huh, You,Lee, Sang-Taek,Ryu, Woon-Young,Woo, Jae-Rin 한국섬유공학회 1994 한국섬유공학회지 Vol.31 No.2

Weaving is the technology to form 2-dimensional structures. where weft yarn is inserted orthogonal into the opened sheets of warp yarn groups. The weft insertion is realized in various methods. The modern technology to insert weft yarns doesn't use the shuttle. The shuttle looms represent high performance and produce good quality fabric. However the new technology has induced some problems which were not so serious in the past: first of all the fault of the stop mark which occurs as a result of the intermittent operations of weaving machines. This type of fault is occupying at present the most of the faults in fabrics manufactured by shuttle looms. In this study it was dealt with how the stop mark occurred and how the starting up conditions could affect the quality of the woven fabrics. The experimental research revealed that 1) the weft density variation at the moment of machine stop resulted to stop nark ranged 1 or 2 picks. 2) during the machine starting up the most of the stop mark took place ranging 2∼3 picks, 3) the irregularity of the weft density during the machine start up resulted from the velocity overshoot in the acceleration period, and 4) the starting up position of the reed between 0 to 180 degrees in the weaving cycle had the effect to reduce the stop mark fault.

섬유이주현상 해석을 위한 화상처리기법의 응용

김영률,허유,류운영,Kim, Young Ryul,Huh, You,Ryu, Woon Young 한국섬유공학회 1998 한국섬유공학회지 Vol.35 No.10

This study proposes a visualization technique with image analyzing system in order to quantitatively analyze the migration behaviour of staple fibers in yarn. The 3-D plots of constituent fibers were obtained and rotational frequencies of the fibers along the yarn axis were measured using the fast fourier transformation (FFT). The results were experimentally identified by the accumulation of the rotational angles of fibers. As migration parameters, the mean fiber position, root mean square (rms) deviation, migration intensity and migration frequency, were calculated from experimental measurements and compared with those of the idealized yarn structure.

링 방적사의 섬유 이주거동에 관한 연구(I) - 꼬임과 정방장력의 영향 -

김영률,허유,류운영,Kim, Young-Ryul,Huh, You,Ryu, Woon-Young 한국섬유공학회 1999 한국섬유공학회지 Vol.36 No.7

Fiber migration of ring spun yarns of different twist levels produced under different spinning tension was measured using the image processing technology. The experimental results reveal several new structural characteristics which can be affected by twist. The decrease of the mean fiber position as the twist multiplier (T.M.) increases shows the fact that the yarn packing density near the yarn axis becomes greater than that in the peripheral zone as more twists is introduced into the yarn. The reduction of the rms deviation with increase of the T.M. values means that the individual fibers cannot be allocated in a wide range of the yarn cross-section as the number of twists increases. In other words, twists constrain the fiber motion in such a way that the magnitude of the radial position variation of fibers along the yarn axis decreases. The constituent fibers, however, alter the radial positions in a more intensive extent as more twists are given to the yarn. from the results, it is also found that one migration occurs as 4~5 turns of twist are inserted to the yarn. The orientation angle increases as the number of twist in the yarn increases, which supports the results for the effect of twist on migration intensity. And the most frequent orientation angles are obtained at the radial position 0.5 of the yarn cross-section independent of the yarn twists. But the spinning tension does not affect fiber migration. The twist affects the yarn hairiness through fiber migration.

새로운 오우픈엔드 정방방식의 연구

우범식,이재곤,류운영,허유,Woo, Bum-Shick,Lee, Jae-Kon,Ryu, Woon-Young,Heo, You 한국섬유공학회 1978 한국섬유공학회지 Vol.15 No.4

In order to investigate the possibility of improvement of the open end spinning machine which has higher productivity and is more economical than the existing ones, 5 kinds of new open end spinning equipments were designed and operated to produce cotton yarns. The two of those five, enclosed rotor with grooved twister and open rotor with grooved twister, were operated only to produce yarns of Ne 8.5, Ne 4.0 respectively. The quality of both yarns were inferior. The other three types of five, the closed rotor, the closed rotor with radial twister and closed rotor with pinned twister, were operated to produce cotton yarns of Ne 11.0, Ne 11.9 and Ne 10.5 respectively. The quality of produced yarns with these three equipments was fairly good and acceptable.

Cubic Spline에 의한 Munsell Color Space Data Point의 확장 및 Smoothing

이종문(John M. Rhee),김용구(Yong Ku Kim),류운영(Woon Young Ryu),김진우(Jin Woo Kim) 한국염색가공학회 1990 韓國染色加工學會誌 Vol.2 No.3

소모사(단사)의 꼬임수와 잔털에 관한 연구

류운영 경희대학교 산학협력기술연구원 1996 산학협력기술연구논문집 Vol.2 No.-

The numbers of hairs of the lengths, over 1mm, 2mm, 3mm, 4mm, 6mm and 8mm on the worsted single yarns are increased with the decrease of twist multiplier insected on them. When we coated oils on the surface of the yarns, the number of short hairs less than 6mm is significantly decreased compared with those of non oiled yarns. However the number of longer hairs more than 6mm is not decreased with the oiling to the yarn surfaces. Gas singeing of the yarn fairs was very effective to decrease the number of longer hairs than 3mm and with the result of singeing the remained number of hairs for raw white single yarn was only 6-8% of the number of the hairs before singeing and 10-11% for dyed single yarns.

제주도산 양모의 품질에 관한 연구

김갑진,허유,류운영 慶熙大學校 1980 論文集 Vol.10 No.-

In this study, it was tried to obtain the data about wool quality continued to the prior publication, some physical and chemical properties of wool from Jae Ju-Do in Korea where there have been bred about 1300 sheep of Romneymarsh and Corriedale were examined. The results, tested and analyzed, are as the followings. The scouring yield of wool from Jae Ju-Do is about 75%, which is higher than that of Australian wool and UnBong Wool. The quality number is 48's for Romneymarsh and 56's for Corriedale. The thickness is comparatively even. The content of cystine and cysteine is 524-532 μ mole/g which is approximately equal to that of Australian Merino wool and greatly higher than that of UnBong Wool. The above results suggest that Jae Ju-Do can be developed as a wool producing district in Korea.