• 제목/요약/키워드: Angular

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초정밀 앵귤러 컨택트 볼 베어링 개발

  • 현준수;문호근;박태조
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1998년도 제27회 춘계학술대회
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    • pp.300-306
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    • 1998
  • A high precision angular contact ball bearing is developed by Hanwha Machinery Co. The developed bearing is 7004C with P4 class. The performance test was succeful until 60,000 rpm.

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GEOMETRY ON EXOTIC HYPERBOLIC SPACES

  • Kim, In-Kang
    • 대한수학회지
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    • 제36권3호
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    • pp.621-631
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    • 1999
  • In this paper we briefly describe the geometry of the Cayley hyperbolic plane and we show that every uniform lattice in quaternionic space cannot be deformed in the Cayley hyperbolic 2-plane. We also describe the nongeometric bending deformation by developing the theory of the Cartan angular invariant for quaternionic hyperbolic space.

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엘리트 펜싱 선수들의 팡트 동작에 따른 무릎 신전근 근력과 각가속도의 상관 (Correlation of isokinetic strength and angular velocity of knee during Fente motion in elite fencer)

  • 김기현;김태규
    • 디지털융복합연구
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    • 제12권9호
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    • pp.407-415
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    • 2014
  • 본 연구의 목적은 펜싱의 각 세부종목과 성별에 따른 팡트 동작에서의 무릎관절 운동역학을 분석하고 무릎 신전근의 다양한 속도에 대한 등속성 근력을 측정하여, 이들의 상관관계를 확인함으로써 펜싱 세부종목과 성별에 따른 훈련프로그램 및 재활프로그램을 개발하는 데에 기초 자료를 제공하고자 하는 것이다. 대한민국 국가대표 선수촌에서 훈련 중인 플뢰레 10명 (남자4명), 에페 10명 (남자 6명), 사브르 11명 (남자 5명) 등 총 31명의 엘리트 펜싱선수들을 대상으로 하였고, $60^{\circ}/s$, $180^{\circ}/s$, $300^{\circ}/s$의 각속도에 대한 무릎 신전근의 원심성 및 구심성 등속성 근력(PT/BW, WK/BW)과 팡트 동작에서 발생하는 무릎관절의 굴곡 (P1) 및 신전 (P2) 각가속도를 측정하였다. 무릎 신전근과 무릎관절 각가속도의 상관관계를 피어슨의 상관관계 계수 (r)를 통해 확인하였고, 모든 통계적 유의수준은 ${\alpha}=.05$로 설정하였다. 펜싱에서 기본이 되는 팡트 동작에서의 무릎관절 움직임에 있어서 요구되는 무릎 신전근의 근력이 펜싱의 세부종목과 성별에 따라 차이가 난다는 것을 확인할 수 있었다.

사무직근로자의 요추부 굴곡근 및 신전근의 등속성 근력평가 서울시 일부지역의 21세 $\sim$ 49세 남자직장인을 중심으로 (Isokinetic Evaluation of the Trunk Flexors and Extensors for the White Collar Workers in Adult Males)

  • 오승길;최병옥
    • 대한물리치료과학회지
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    • 제7권1호
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    • pp.377-396
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    • 2000
  • After warming-up exercise for 20 minutes, Isokinetic measurement of trunk strength for flexor and extensor was done by using Cybex 6000 TEF Unit on 91 healthy male white workers from 22years old to 49 years old, and compared each other. 20 repetitions of trunk extension-flexion were done at $120^{\circ}$/sec angular velocity. After resting for 1 minutes, Four repetitions at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec) were done with 30 seconds of resting interval between each angular velocity. The purpose of this study is to obtain the isokinetic normative strength values for trunk extensors and flexors, and is to know the correlation between age, height, weight of subjects and data from isokinetic trunk strength measurement, and is to provide a guideline for exercise program of male white collar workers The collected data were analyzed by ANOVA, Duncan's Multiple Range Test, and Pearson correlation coefficiency in PC-SAS program. The results obtained were as follow; 1. There is significant positive-correlation with the statistic value between weight and peak torque of trunk muscles at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec)(p<01), between height and peak torque of trunk muscles at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec) except peak torque of trunk flexor at $60^{\circ}$/sec(p<01). 2. There is nagitive-correlation between age and peak torque of trunk muscles at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec), there is significant differences with statistic value between age and peak torque of trunk extensor at $120^{\circ}$/sec(p<.01). 3. Mean peak torque and mean peak torque % by body weight of trunk extensor is 1.1 times higher values than trunk flexor at $60^{\circ}$/sec. 4. There is the increase in peak torque angle of trunk flexor with increasing of age, and the decrease in peak torque angle of trunk flexor with increasing of age at two different angular velocities($60^{\circ}$/sec, $120^{\circ}$/sec). there is significant differences with statistic value in peak torque angle of trunk flexor at $120^{\circ}$/sec(p<.01). 5. There is significant decrease in endurance ratio of trunk extensor with increasing of age at $120^{\circ}$/sec(p<.01). In conclusion, peak torque of trunk extensor is 1.1 times higher values than trunk flexor in healthy male white collar workers.

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테니스 한손 백핸드 스트로크와 양손 백핸드 스트로크 동작의 3차원 운동학적 비교 분석 (3-D Kinematic comparison of One Hand Backhand Stroke and Two Hand Backhand Stroke in Tennis)

  • 최지영;신제민
    • 한국운동역학회지
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    • 제15권4호
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    • pp.85-95
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    • 2005
  • The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle during One Hand Backhand Stroke and Two Hand Backhand in tennis. For the movement analysis three dimensional cinematographical method(APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVIEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and racket head direction were defined. 1. In three dimensional maximum linear velocity of racket head the X axis and Y axis(horizontal direction) showed $-11.04{\pm}2.69m/sec$, $-9.31{\pm}0.49m/sec$ before impact, the z axis(vertical direction) maximum linear velocity of racket head did not show at impact but after impact this will resulted influence upon hitting ball. It could be suggest that Y axis velocity of racket head influence on ball direction and z axis velocity influence on ball spin after impact. The stance distance between right foot and left foot was mean $75.4{\pm}5.86cm$ during one hand backhand stroke and $72.6{\pm}4.67cm$ during two hand backhand stroke. 2. The three dimensional anatomical angular displacement of trunk in interna rotation-external rotation showed most important role in backhand stroke. and is follwed by flexion-extension. the three dimensional anatomical angular displacement of trunk did not show significant difference between one hand backhand stroke and two hand backhand stroke but the three dimensional anatomical angular displacement of trunk was bigger than one hand backhand stroke. 3. while backhand stroke, the flexion-extension and adduction-abduction of right shoulder joint showed significant different between one hand backhand stroke and two hand backhand stroke. the three dimensional anatomical angular displacement of right shoulder joint showed more flex and abduct in one hand backhand stroke. 4. The three dimensional anatomical angular displacement of left shoulder showed flexion, adduction, and external rotation at impact. after impact, The angular displacement as adduction-abduction of left shoulder changed motion direction as abduction. angular displacement of left shoulder as flexion-extension showed bigger than the right shoulder.