• Title/Summary/Keyword: low twist

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A Study on the Feed Characteristics of Twist Friction Driver (Twist Friction Driver의 이송특성에 관한 연구)

  • Jeong, Jun-Hui;Lee, Eung-Suk;An, Dong-Yul
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.934-939
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    • 2004
  • This paper propose a study on the Feed Characteristics of Twist Friction Driver. We are using Twist Friction Driving mechanism system. The system consists of Twist Friction Driver elements such as driving shaft, driven roller, Spring for pre-load, Air bearing guide, Servo motor, and measuring devices such as Encoder of Servo motor, Laser interferometer, LVDT . The Twist Friction driver is mechanically simple and very quiet at high speed, and has low pre-load. So The Twist Friction driver can materialize an ultra precision feed-resolution. The feed characteristics of the driver is determined by slip and angular error, backlash.

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Power Consumption and Viewing Angle Characteristics Dependent on Liquid Crystal's Twist Angle in Reflective Twisted Nematic Mode (반사형 TN mode의 Twist angle에 따른 소비전력과 시야각 특성)

  • 송제훈;정태봉;이승희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.2
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    • pp.207-211
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    • 2004
  • We have performed computer simulation to obtain a globa1 optimization of power consumption and viewing angle characteristic of reflective twisted nematic (R-TN) mode liquid crystal display (LCD) with sin81e polarizer and λ/4 plate. Our studies shout that with increasing the twist angle, a steepness of reflectance-voltage curve increase, operation voltages decreases, the region where contrast ratio (CR) greater than 10 increases but the reflectance of the white state starts to decrease at above the twist angle of 75$^{\circ}$. Above the twist angle of 90$^{\circ}$, the R-TN mode LCD shows the most favorable combination of low consumption and good viewing angle characteristic.

NON-COPLANAR MAGNETIC RECONNECTION AS A MAGNETIC TWIST ORIGIN

  • CHAE JONGCHUL
    • Journal of The Korean Astronomical Society
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    • v.32 no.2
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    • pp.137-147
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    • 1999
  • Recent studies show the importance of understanding three-dimensional magnetic reconnect ion on the solar surface. For this purpose, I consider non-coplanar magnetic reconnection, a simple case of three-dimensional reconnect ion driven by a collision of two straight flux tubes which are not on the same plane initially. The relative angle e between the two tubes characterizes such reconnection, and can be regarded as a measure of magnetic shear. The observable characteristics of non-coplanar reconnection are compared between the two cases of small and large angles. An important feature of the non-coplanar reconnect ion is that magnetic twist can be produced via the re-ordering of field lines. This is a consequence of the conversion of mutual helicity into self helicities by reconnection. It is shown that the principle of energy conservation when combined with the production of magnetic twist puts a low limit on the relative angle between two flux tubes for reconnect ion to occur. I provide several observations supporting the magnetic twist generation by reconnection, and discuss its physical implications for the origin of magnetic twist on the solar surface and the problem of coronal heating.

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Two Children with Saethre-Chotzen Syndrome Confirmed by the TWIST1 Gene Analysis (TWIST1 유전자의 돌연변이가 확인된 Saethre-Chotzen 증후군 2례)

  • Ko, Jung-Min;Yang, Jung-Ah;Jeong, Seon-Yong;Yoon, Soo-Han
    • Journal of Genetic Medicine
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    • v.8 no.2
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    • pp.130-134
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    • 2011
  • Saethre-Chotzen syndrome is an autosomal dominant craniosynostosis syndrome, usually involving unior bilateral coronal synostosis and mild limb deformities, and is induced by loss-of-function mutations of the TWIST1 gene. Other clinical features of this syndrome include ptosis, low-set ears, hearing loss, hypertelorism, broad great toes, clinodactyly, and syndactyly. The authors of the present study report 2 children with clinical features of Saethre-Chotzen syndrome who showed mutations in the TWIST1 gene, and is the first molecular genetic confirmation of Saethre-Chotzen syndrome in Korea. The molecular genetic testing of the TWIST1 gene for patients with coronal synostoses is important to confirm the diagnosis and to provide adequate genetic counseling.

Design of Transflective Low-twist VA mode for High Transmittance (높은 투과율을 갖는 반투과형 Low-Twist VA mode 설계)

  • 도희욱;백봉진;이서헌;윤태훈;김재창
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.02a
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    • pp.118-119
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    • 2003
  • 휴대용 통신기기의 발달로 인해 실내 및 실외 환경에서 높은 성능을 발휘하는 LCD 소자가 요구되고 있다. 후면광원을 사용하는 투과형 LCD는 실내 혹은 어두운 곳에서 높은 휘도와 명암대비비를 가지는 반면 실외나 밝은 곳에서는 높은 휘도 및 명암대비비를 보일 수 없다. 그에 반해 반사형 LCD는 주변광을 광원으로 사용하므로 실외 혹은 밝은 곳에서의 전기광학 특성이 양호한 장점이 있지만 실내 및 어두운 곳에서의 사용이 제한된다. (중략)

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Welding behavior between Zn-coated steel plate and free cutting carbon steel rod by Nd:YAG laser beam (Nd:YAG 레이저빔을 이용한 아연도금강판(SECC)과 쾌삭강봉(SUM24L)의 용접에 관한 연구)

  • 노영태;김병철;김도훈;윤갑식
    • Laser Solutions
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    • v.4 no.3
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    • pp.30-39
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    • 2001
  • This work was tamed out to apply a laser welding technique in joining between a Zn coated low carbon steel plate(SECC) and a free cutting carbon steel shaft(SUM24L) with or without W coating. Experiments were carried out and analysed by applying the FD(factorial design)method to obtain the optimum Laser welding condition. Optical microscopy, SEM, TEM and XRD analyses were performed in order to observe the microstructures in the fusion zone and the HAZ. Mechanical properties of the welded specimens were examined by microhardness test, tensile test and twist test. There was no flawed Zn in the fusion zone by EDS analysis. This means that during the welding process, Zn gas could be eliminated by appropriate shielding gas flow rate and butt welding gap. Ni coating itself did not influence on the tensile strength and hardness. However, twist bending strength and the weld depth of the Ni-coated free cutting carbon steel were lower as compared with those of the uncoated free cutting carbon steel. It was attributed to a lower absorbance of laser beam to the shin Ni surface. According to the results of the factorial design tests, the twist bending strength of welded specimens was primarily affected by pulse width, laser power, frequency and speed.

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Potentials of elastic seismic design of twisted high-rise steel diagrid frames

  • Kim, Seonwoong;Lee, Kyungkoo
    • Steel and Composite Structures
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    • v.18 no.1
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    • pp.121-134
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    • 2015
  • This paper is to investigate the potentials of the elastic seismic design of twisted high-rise steel diagrid frame buildings in the strong wind and moderate/low seismicity regions. First, the prototypes of high-rise steel diagrid frames with architectural plans that have a twist angle of 0 (regular-shaped), 1, and 2 degrees were designed to resist wind. Then, the effects of the twist angle on the estimated quantities and structural redundancies of the diagrid frames were examined. Second, the seismic performance of the wind-designed prototype buildings under a low seismicity was evaluated. The response spectrum analysis was conducted for the service level earthquake (SLE) having 43-year return period and the maximum considered earthquake (MCE) having 2475-year return period. The evaluation resulted that the twisted high-rise steel diagrid frames resisted the service level earthquake elastically and most of their diagrid members remained elastic even under the maximum considered earthquake.

The Study on the Physical Property of PET Filament in the 2-for-1 Twist Setting Process (2-for-1 연사 세팅 공정에서의 PET 필라멘트 사물성에 관한 연구)

  • 이응곤;김승진;김태훈
    • Textile Coloration and Finishing
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    • v.12 no.2
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    • pp.89-95
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    • 2000
  • Effect of twist-setting time, temperature and cylinder layer for the physical properties of the twist yarn were investigated by separated 9 layer from yarn cylinder. Obtained results were as follow. Shrinkage of the yarn in middle layer shows high value with heat-permeation and in inner's shows low value because of cylinder hardness. And then yarn thermal shrinkage in outer layers shows more or less high value because twist yarn in the outer layer sets more faster. Concerning to the difference on the yam physical properties among cylinder layers, the changes on physical properties shows significant differences from the 7th layer to the last one. Linear density, T.P.M and initial modulus decreases but snarl index increases.

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능동 비틀림 제어에 용이한 블레이드의 스파형상 선정

  • Bae, Jae-Seong
    • Proceeding of EDISON Challenge
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    • 2015.03a
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    • pp.184-190
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    • 2015
  • On wide variety of fields, studies on active twist control are becoming more active. For effective twist control, blades have to have low torsional stresses with high torsional deformations to the same magnitude of torque acting on its cross-section. In this study, 2D sectional analysis and 3D finite element analysis were made for 5 different blades with each having different cross - sections which have different spars. The results from 2D sectional analysis, were then put into 3D blade deformation and stress calculations which lead to analysis. Outcomes from 2D and 3D analysis, showed that on the same torque and concentrated load conditions, the blade with 'C' shaped spar was the best of all the blades which were used in this study.

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Design of X-band Broadband Twist Reflector Using Hybrid Particle Swarm Optimization (Hybrid Particle Swarm Optimization 기법을 적용한 X-대역 광대역 편파 변환기 설계)

  • Hwang, Keum-Cheol
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.4
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    • pp.390-395
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    • 2009
  • Design and optimization of a broadband meander-line twist reflector was performed for X-band application. Based on the equivalent transmission line model, the polarization twist performance was evaluated. Genetic analysis, particles swarm, and hybrid swarm optimizations were employed to obtain the optimized geometrical parameters. The optimized design exhibits low cross-polarization level below - 25 dB between 8.45 and 11.38 GHz. The polarization twist loss was below 0.2 dB. Comparison between computed and simulated results was also discussed.