• Title/Summary/Keyword: Rotation axis

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The Validity Test of Upper·Forearm Coordinate System and the Exploratory Analysis of the Interactive Effect between Flexion/Extension and Pronation/Supination during Elbow Joint Motion (주관절 운동의 상완·전완좌표계 타당도 및 굴곡/신전과 회내/회외의 상호작용)

  • Kim, Jin-Uk
    • Korean Journal of Applied Biomechanics
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    • v.20 no.2
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    • pp.117-127
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    • 2010
  • The axes of upper forearm coordinate system have been considered as principal axis of each segment which was component of elbow joint. The purpose of this study was to verify whether the mean direction(principal axis) of instantaneous axes of rotation for pure flexion/extension motion coincided with the flexion/extension axis of upper forearm coordinate system. The same procedure was done for pronation/supination motion. Furthermore, it was tested indirectly that there was an interaction effect between the two rotational motions. The results showed that most segment coordinate axes statistically were not consistent with the mean directions of flexion/extension and pronation/supination axes of rotation. From the results, it would be concluded that the ISB coordinate systems was proved to be a little valid for human movement analysis. There also was an effect of pronation/supination angles on flexion/extension motion.

Kinematic properties of the Ursa Major Cluster

  • Kim, YoungKwang;Lee, Young Sun;Beers, Timothy C.
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.2
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    • pp.30.3-31
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    • 2015
  • We present a kinematic analysis of 172 likely member galaxies of the Ursa Major Cluster. In order to understand the dynamical state of the cluster, we investigate the correlation of the cluster morphology with rotation, the velocity dispersion profile, and the rotation amplitude parallel to the global rotation direction. Both the minor axis and the rotation are very well-aligned with the global rotation axis in the outer region at half radius (> 0.5 $R_{max}$), but not in the inner region. The cluster exhibits low velocity dispersion and rotation amplitude profiles in the inner region, but higher in the outer. Both profiles exhibit outwardly increasing trends, suggesting an inside-out transfer of angular momentum of dark matter via violent relaxation, as revealed by a recent off-axis major-merging simulation. From Dressler-Schectman plots in the plane of galactic positions, and velocity versus position angle of galaxy, we are able to divide the Ursa Major Cluster into two substructures: Ursa Major South (UMS) and Ursa Major North (UMN). We derive a mass of $3.2{\times}10^{14}M_{\odot}$ for the cluster through the two-body analysis by the timing argument with the distance information (37 for UMN and 36 for UMS) and the spin parameter of ${\lambda}=0.049$. The two substructures appear to have passed each other 4.4 Gyr ago and are moving away to the maximum separation.

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Effects of seed orientation on the growth behavior of single grain REBCO bulk superconductors

  • Lee, Hee-Gyoun
    • Progress in Superconductivity and Cryogenics
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    • v.19 no.2
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    • pp.9-13
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    • 2017
  • This study presents a simple method to control the seed orientation which leads to the various growth characteristics of a single grain REBCO (RE: rare-earth elements) bulk superconductors. Seed orientation was varied systematically from c-axis to a-axis with every 30 degree rotation around b-axis. Orientations of a REBCO single grain was successfully controlled by placing the seed with various angles on the prismatic indent prepared on the surface of REBCO powder compacts. Growth pattern was changed from cubic to rectangular when the seed orientation normal to compact surface was varied from c-axis to a-axis. Macroscopic shape change has been explained by the variation of the wetting angle of un-reacted melt depending on the interface energy between $YBa_2Cu_3O_{7-y}$ (Y123) grain and melt. Higher magnetic levitation force was obtained for the specimen prepared using tilted seed with an angle of 30 degree rotation around b-axis.

VARIATION IN THE GROWTH PATTERN OF THE FACE: A LONGITUDINAL COMPUTERIZED RECTILINEAR CEPHALOMETRIC STUDY (안면골의 성장회전에 관한 연구)

  • Kim, Il-Bong;Sung, Jae-Hyun;Chung, Kyu-Rhim
    • The korean journal of orthodontics
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    • v.15 no.1
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    • pp.123-140
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    • 1985
  • Variation in the facial pattern and effect of the rotational jaw growth on the facial proportion were studied in serial cephalometric radiographs of 40 Korean children (25 boys, 15 girls) ranging in age from 6 to 13 years. According to Y-axis (N-S-Gn) growth change during the 7 years of period, the subject who had exhibited 'wave-like' manner of Y-axis growth change within ${\pm}\;2^{\circ}$ was classified to the Parallelwise group and the subject who had exhibited Y-axis increase more than $+2^{\circ}$ was classified to the Clockwise rotation group and the subject who had exhibited Y-axis decrease more than $-2^{\circ}$ was classified to the Counterclockwise rotation group. For the comparison of each group, a total of 22 morphologic variables were employed and the data were analyzed by means of computer morphometrics and statistical methods. On the basis of the finding of this study, the following trends were established. 1. The Parallelwise group was $75\%$, the Clockwise rotation group was $12.5\%$ and the Counter-clockwise rotation group was $12.5\%$. 2. The growth pattern of cranial base was related to the rotation of mandible. 9. Maxillary prognathism was occured in the Counterclockwise rotation group and the rotation of palatal plane was occured in the Clockwise rotation group. 4. Mandibular prognathism was occured in the Parallelwise and the Counterclockwise rotation groups, especially in the Counterclockwise rotation group. 5. The degree of maxillo-mandibular divergency was constant in the Clockwise rotation group but decreased in the Counterclockwise rotation and the Parallelwise groups, especially in the Counterclockwise group. 6. There were no differences in the size of the anterior upper facial height (N-ANS) and the posterior lower facial height ((Go-Me)-PNS) but there were differences in the size of the anterior lower facial height (ANS-Me) and the posterior upper facial height ((S-N)-PNS) between each group. 7. The growth increment and the size of the facial depth was not related to the growth pattern of the face but the growth increment and the size of the facial height was related to the growth pattern of the face. 8. Proportional change due to the facial growth rotation was concentrated in the anterior lower face. 9. The most apparent difference between each group was happened in the size of the posterior cranial base (S-Ba) and the facial length (S-Gn).

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A Study on the Detection of Axis-Rotation in Contact Lenses (콘택트렌즈 회전량 검출에 대한 연구)

  • Lee, Dong-Hee;Kim, Jung-Hee;Cha, Jung-Won
    • Journal of Korean Ophthalmic Optics Society
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    • v.10 no.4
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    • pp.255-259
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    • 2005
  • When we wear contact lenses for correcting astigmatism, we often experience the axis-rotation of contact lenses that is happened in case we could not fit the axis of lens exactly or by the eyelid used to blink. In this case, because the exact correcting state becomes in the wrongly correcting state, the asthenopia is led, and the decline of eyesight can be led. For this reason, we need to know axis-rotating degrees of contact lenses. If a contact lens rotated, a residual astigmatism may be detected in the refraction examination after wearing. Using this, we developed a program that calculates the axis-rotating amount of contact lenses.

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The Astigmatism Calculation according to the Bevel Position of Decentered Spectacle Lens: Prism Prescription Lens by Eccentricity (편심된 안경렌즈의 산각 위치에 따른 비점수차 계산: 편심에 의한 프리즘 처방)

  • Kim, Sang-Hyun;Seo, Ji-Keun
    • Journal of Korean Ophthalmic Optics Society
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    • v.11 no.2
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    • pp.77-83
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    • 2006
  • We have studied the astigmatism according to the bevel position and the tilting(pantoscopic) angle of decentered spectacle lens for prism prescription. For prism prescription, generally we make a general spectacle lens into decentered spectacle lens. At this time the bevel position of decentered lens is a important matter, because the difference between optic axis and visual axis occur aberrations. Using the calculation we find that the case that the axis of bevel rotation band passes the front curvature center of (+) lens has a smaller astigmatism than the case that the axis of bevel rotation band passes the rear curvature center of (+) lens and that the case that the axis of bevel rotation band passes the rear curvature center of (-) lens has a smaller astigmatism than the case that the axis of bevel rotation band passes the front curvature center of (-) lens. We find the lens with higher refraction index has a smaller astigmatism.

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Magnetic Fields of the Youngest Protostellar System L1448 IRS 2 revealed by ALMA

  • Kwon, Woojin;Stephens, Ian W.;Tobin, John J.;Looney, Leslie W.;Li, Zhi-Yun;Crutcher, Richard M.;Kim, Jongsoo;van der Tak, Floris F.S.
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.1
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    • pp.44.3-45
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    • 2018
  • Magnetic fields affect star formation in a broad range of scales from parsec to hundreds au. In particular, interferometric observations and ideal magneto-hydrodynamic (MHD) simulations have reported that formation of a rotation-supported disk at the earliest young stellar objects (YSOs) is largely suppressed by magnetic fields aligned to the rotational axis of YSOs: magnetic braking. Our recent ALMA observations toward L1448 IRS 2, which has a rotation detected and its magnetic fields aligned to the rotation axis (poloidal fields) in ~500 au scales, show that the fields switch to toroidal at the center in ~100 au scales. This result suggests that magnetic braking may not be so catastrophic for early disk formation even in YSOs with magnetic fields aligned to the rotational axis.

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Rough surface characterization using off-axis digital holographic microscopy compensated with self-hologram rotation

  • Ibrahim, Dahi Ghareab Abdelsalam
    • Current Applied Physics
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    • v.18 no.11
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    • pp.1261-1267
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    • 2018
  • In this paper, an off-axis digital holographic microscopy compensated with self-hologram rotation is presented. The process is implemented via subtracting the unwrapped phase maps of the off-axis parabolic hologram and its rotation $180^{\circ}$ to eliminate the tilt induced by the angle between the spherical object wave O and the plane reference wave R. Merit of the proposed method is that it can be done without prior knowledge of physical parameters and hence can reconstruct a parabolic hologram of $1024{\times}768$ pixels within tens of milliseconds since it doesn't require a digital reference wave. The method is applied to characterize rough gold bumps and the obtained results were compared with those extracted from the conventional reconstruction method. The comparison showed that the proposed method can characterize rough surfaces with excellent contrast and in realtime. Merit of the proposed method is that it can be used for monitoring smaller biological cells and micro-fluidic devices.

Research on the Basic Rodrigues Rotation in the Conversion of Point Clouds Coordinate System

  • Xu, Maolin;Wei, Jiaxing;Xiu, Hongling
    • Journal of Information Processing Systems
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    • v.16 no.1
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    • pp.120-131
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    • 2020
  • In order to solve the problem of point clouds coordinate conversion of non-directional scanners, this paper proposes a basic Rodrigues rotation method. Specifically, we convert the 6 degree-of-freedom (6-DOF) rotation and translation matrix into the uniaxial rotation matrix, and establish the equation of objective vector conversion based on the basic Rodrigues rotation scheme. We demonstrate the applicability of the new method by using a bar-shaped emboss point clouds as experimental input, the three-axis error and three-term error as validate indicators. The results suggest that the new method does not need linearization and is suitable for optional rotation angle. Meanwhile, the new method achieves the seamless splicing of point clouds. Furthermore, the coordinate conversion scheme proposed in this paper performs superiority by comparing with the iterative closest point (ICP) conversion method. Therefore, the basic Rodrigues rotation method is not only regarded as a suitable tool to achieve the conversion of point clouds, but also provides certain reference and guidance for similar projects.

Difference in Rotation Pattern of Toric Soft Contact Lenses with Different Axis Stabilization Design (축 안정화 디자인이 상이한 토릭소프트콘택트렌즈의 회전 양상 차이)

  • Park, So Hyun;Kim, Dong Yeon;Choi, Joo Hee;Byun, Hyun Young;Kim, So Ra;Park, Mijung
    • Journal of Korean Ophthalmic Optics Society
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    • v.20 no.2
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    • pp.133-140
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    • 2015
  • Purpose: It was investigated whether two different stabilization designs of toric contact lenses changed the rotational axis and degree of toric lenses according to body posture and gaze direction in the present study. Methods: Toric soft contact lenses with Lo-Torque$^{TM}$ design and ASD design (accelerated stabilized design) were fitted on 52 eyes aged in 20s-30s. Then, rotational degree was measured at the five gaze directions including front gaze and the lying position. Results: When gazing the front and vertical directions in the upright posture, lens was much rotated to nasal side for the Lo-Torque$^{TM}$ design and temporal side for the ASD design. When gazing horizontal direction, both design lenses were rotated against to the gaze direction. Rotation degree was the smallest at superior direction gaze and the largest at nasal gaze. In case of the rotation degree less than $5^{\circ}$, Lo-Torque$^{TM}$ design was more frequent when gazing front and vertical directions, and ASD design was more frequent when gazing horizontal direction. In addition, the lens with Lo-Torque$^{TM}$ design was lesser rotation degree than with ASD design immediately after lying. On the other hand, the lens with ASD design was lesser rotation degree than with Lo-Torque$^{TM}$ design 1 minute later after lying. Conclusions: This study confirmed that axis rotation of the lens induced by gaze direction and posture was different according to axis stabilization design during wearing toric soft contact lens.