• Title/Summary/Keyword: Phase angles

Search Result 452, Processing Time 0.023 seconds

Phase Shift Analysis of 6Li Elastic Scattering on 12C and 28Si at Elab = 318 MeV

  • Kim, Yong Joo
    • New Physics: Sae Mulli
    • /
    • v.68 no.12
    • /
    • pp.1331-1337
    • /
    • 2018
  • We present a three-parameter phase shift model whose form is the same as that of Coulombmodified Glauber model obtained from Gaussian nuclear densities. This model is applied to the $^6Li+^{12}C$ and the $^6Li+^{28}Si$ elastic scatterings at $E_{lab}=318MeV$. The calculated differential cross sections provide quite a satisfactory account of the experimental data. The diffractive oscillatory structures observed at forward angles can be explained as being due to the strong interference between the near-side and the far-side scattering amplitudes. The optical potentials for two systems are predicted by using the method of inversion. The calculated inversion potentials are found to be in fairly good agreements with the results determined from the optical model analysis in the surface regions around the strong absorption radius. We also investigate the effects of parameters in the three-parameter phase shift model on the elastic scattering cross sections.

A Novel Concept of Phase Swapping for Multiple Enhanced Speed Operations of a PM machine using Winding Switching

  • Atiq, Shahid;Hussain, Asif;Kwon, Byung-il
    • Journal of Electrical Engineering and Technology
    • /
    • v.12 no.1
    • /
    • pp.262-271
    • /
    • 2017
  • This paper presents a novel concept of phase swapping to associate multiple flux weakening ranges to a non-salient PM machine without altering any hardware of the machine. The proposed concept enables a dual three-phase machine to be operated with different displacement angles between the two three-phase windings. Hence, different flux weakening ranges using winding switching can be accomplished by applying this concept. It was also demonstrated that the proposed concept can be utilized for the discrete step as well as continuous operation of the machines. Any application requiring a wide speed range operation of up to thirteen times the base speed can benefit from this proposed concept. Analytical, simulation, and experimental results are provided to validate the effectiveness of the proposed concept.

New Phase Energization Strategies for the Minimization of Hybrid Step Motor Torque Ripples (하이브리드 스텝모우터의 토오크 리플 최소화를 위한 새로운 상여자방식)

  • Kim, Yoon-Ho;Yoon, Byung-Do;Eum, Tae-Wook
    • Proceedings of the KIEE Conference
    • /
    • 1991.11a
    • /
    • pp.133-136
    • /
    • 1991
  • New phase-energization strategies are proposed to minimize torque ripple of closed-loop controlled 2-phase Bifilar Hybrid step motors. Lead angle and conduction angles are important parameters in minimizing torque ripple factors. The phase-energization control strategy that minimizes torque ripples for the given average torque is proposed. In this paper, Fourier series are applied to produce the average torque. The strategy is performed by controlling both lead angle and conduction angle of the input voltage wave-form for each phase.

  • PDF

Studies of Molecular Orientation for Ferrielectric Liquid Crystal by Phase Transitions

  • Kim, S.W.;Choi, H.;Song, J.H.;KIm, J.H.;Kumar, S.;Choi, J.W.;Kim, Y.B.;Shin, S.T.
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2000.01a
    • /
    • pp.61-62
    • /
    • 2000
  • We have studied the molecular orientation by the phase transitions of the chiral smectic liquid crystals, 4-(1-Trifluoromethyl-6-ethoxy-hexyloxycarbonlphenyl)-4-nonyloxybiphenyl-4-carbo-xylate (R-TFMEOHPNBC) to seek the original solution of the zig-zag defect using two different experimental techniques; optical system and x-ray scattering. The phase sequence is gamma ferroelectric $(SmC{\gamma}\;^*)$ ${\rightarrow}$ smectic A (SmA) ${\rightarrow}$ isotropic (I). Existence of two layer spacing at chiral smectic phase gives a possibility of the molecular orientation in two different tilt angles, ${\theta}\;_1$ and ${\theta}\;_2$, which are separated each other to the layer normal at a given temperature. The gamma ferroelectric-like phase is, first, discovered in the single compound.

  • PDF

Characteristics of Artificial Earthquake using Recorded Earthquake Data in Korea (국내 지진데이터를 이용한 인공지진가속도 특성)

  • Woo, Woon-Taek;Park, Tae-Won;Jung, Ran
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2003.10a
    • /
    • pp.479-486
    • /
    • 2003
  • The characteristics of harmonic phase angles and phase angle differences contained in earthquake ground motions such as El Centre 1940 NS, Taft1 1952 NS, Hachinohe 1968 NS and Mexico 1985 are figured, which have been mostly overlooked in contrast with the importance placed on harmonic amplitudes. Recently, performance based design method is used for seismic design and seismic retrofitting, which needs nonlinear response analysis, there must be earthquake ground accelerations which contain the phase angle, the phase angle difference and energy input spectrum characteristics of the zone considered to be constructed building structures. To make clear the importance of phase angle differences, responses of 4 recorded earthquake ground motions, 4-earthquake ground motions normalized by 110 gal and 4 artificial earthquake motions compatible to the seismic building code of Korea are compared.

  • PDF

Joint Estimation of Near-Field Source Parameters and Array Response

  • Cui, Han;Peng, Wenjuan
    • Journal of Information Processing Systems
    • /
    • v.13 no.1
    • /
    • pp.83-94
    • /
    • 2017
  • Near-field source localization algorithms are very sensitive to sensor gain/phase response errors, and so it is important to calibrate the errors. We took into consideration the uniform linear array and are proposing a blind calibration algorithm that can estimate the directions-of-arrival and range parameters of incident signals and sensor gain/phase responses jointly, without the need for any reference source. They are estimated separately by using an iterative approach, but without the need for good initial guesses. The ambiguities in the estimations of 2-D electric angles and sensor gain/phase responses are also analyzed in this paper. We show that the ambiguities can be remedied by assuming that two sensor phase responses of the array have been previously calibrated. The behavior of the proposed method is illustrated through simulation experiments. The simulation results show that the convergent rate is fast and that the convergent precision is high.

Phase Angle Control in Resonant Inverters with Pulse Phase Modulation

  • Ye, Zhongming;Jain, Praveen;Sen, Paresh
    • Journal of Power Electronics
    • /
    • v.8 no.4
    • /
    • pp.332-344
    • /
    • 2008
  • High frequency AC (HFAC) power distribution systems delivering power through a high frequency AC link with sinusoidal voltage have the advantages of simple structure and high efficiency. In a multiple module system, where multiple resonant inverters are paralleled to the high frequency AC bus through connection inductors, it is necessary for the output voltage phase angles of the inverters be controlled so that the circulating current among the inverters be minimized. However, the phase angle of the resonant inverters output voltage can not be controlled with conventional phase shift modulation or pulse width modulation. The phase angle is a function of both the phase of the gating signals and the impedance of the resonant tank. In this paper, we proposed a pulse phase modulation (PPM) concept for the resonant inverters, so that the phase angle of the output voltage can be regulated. The PPM can be used to minimize the circulating current between the resonant inverters. The mechanisms of the phase angle control and the PPM were explained. The small signal model of a PPM controlled half-bridge resonant inverter was analyzed. The concept was verified in a half bridge resonant inverter with a series-parallel resonant tank. An HFAC power distribution system with two resonant inverters connected in parallel to a 500kHz, 28V AC bus was presented to demonstrate the applicability of the concept in a high frequency power distribution system.

Analysis of Kinematics and Kinetics According to Skill Level and Sex in Double-under Jump Rope Technique

  • Kim, Dae Young;Jang, Kyeong Hui;Lee, Myeoung Gon;Son, Min Ji;Kim, You Kyung;Kim, Jin Hee;Youm, Chang Hong
    • Korean Journal of Applied Biomechanics
    • /
    • v.27 no.3
    • /
    • pp.171-179
    • /
    • 2017
  • Objective: The purpose of this study was to perform a kinematic and kinetic analysis of double-under jump rope technique according to skill level and sex. Method: Participants comprised a skilled group of 16 (9 males, 7 females), and an unskilled group of 16 with 6 months or less of experience (9 males, 7 females). Five consecutive double-under successes were regarded as 1 trial, and all participants were asked to complete 3 successful trials. The data for these 3 trials were averaged and analyzed after collecting the stable third jump in each trial. The variables used in the analysis included phase duration, total duration, flight time, vertical toe height, stance width, vertical center of mass displacement, and right lower limb ankle, knee, and hip joint angles in the sagittal plane during all events. Results: The skilled group had a shorter phase and total duration and a shorter flight time than the unskilled group. The vertical center of mass displacement and ankle dorsiflexion angle were significantly smaller in the skilled group. The male group had a shorter phase duration than the female group. The vertical toe height was greater, the stance width was smaller, and the ankle and hip flexion angles were smaller in the male group. Conclusion: Variables that can be used to distinguish between skill levels are phase and total duration, flight time, vertical center of mass displacement, and ankle dorsiflexion angle. Differences between sexes in double-under jump rope technique may be related to lower limb flexion angle control.

The Effects of Different Angles of Wedged Insoles on Knee Varus Torque in Healthy Subjects

  • Jung, Do-Young;Kwon, Oh-Yun;Yi, Chung-Hwi;Kim, Young-Ho;Kim, Jang-Hwan
    • Physical Therapy Korea
    • /
    • v.11 no.4
    • /
    • pp.31-41
    • /
    • 2004
  • The purpose of this study was to examine the effect of the angle of a wedged insole on knee varus torque during walking. Fifteen healthy subjects were recruited. Knee varus torque was measured using three-dimensional motion analysis (Elite). Knee varus torque was normalized to gait cycle (0%: initial contact; 100%: ipsilateral initial contact) and stance phase (0%: initial contact; 100%: ipsilateral toe off). The average peaks of knee varus torque during the stance phase of the gait cycle according to the different insole angles (10 or 15 degrees) were compared using one-way ANOVA with repeated measures. The results showed that in the early stance phase, the average peak knee varus torque increased significantly for both the medial 10 and 15 degree wedged insole conditions and decreased significantly for both the lateral 10 and 15 degree wedged insole conditions as compared with no insole (p<.05). However, there were no significant differences between the 10 and 15 degree wedged insole conditions with either the medial or lateral wedged insole (p>.05). In the late stance phase, the average peak knee varus torque increased significantly for the medial 10 and 15 degree wedged insole conditions (p<.05), but not for the lateral 10 and 15 degree wedged insole conditions as compared with no insole (p>.05). We suggest that these results may be beneficial for manufacturing foot orthotic devices, such as wedged insoles, to control medial and lateral compartment forces in the knee varus-valgus deformity. Further studies of the effects of wedged insole angle on knee varus torque in patients with medial-lateral knee osteoarthritis are needed.

  • PDF

Effects of High-Intensity Interval Training on Motor Skills Recovery in Sciatic Nerve Crush-Induced Rats

  • Kim, Ki-Hyun;Shin, Hyung-Soo;Jung, Nam-Jin;Hwangbo, Gak
    • Journal of the Korean Society of Physical Medicine
    • /
    • v.15 no.1
    • /
    • pp.43-54
    • /
    • 2020
  • PURPOSE: This study examined the effects of mild-intensity exercise (MIE) and high-intensity interval exercise (HIIE) on the recovery of the motor function over time in sciatic nerve crush injury rats. METHODS: The MIE group ran on a treadmill at a speed of 8.3 m/min to perform low-intensity training with maximum oxygen uptakes ranging from 40 to 50%. The HIIE group ran on the treadmill at a speed of 25 m/min to perform high-intensity training with a maximum oxygen uptake of 80%. The interval training was performed based on a 1:1 work-to-rest ratio. The effects of each form of exercise on the rats' walking abilities following their recovery from the peripheral nerve injuries were evaluated based on the results of behavior tests performed at one and 14 days. RESULTS: According to the test results, the MIE group showed significant improvements in the rats' ankle angle in the initial stance phase, and in the ankle and knee angles in the toe-off phase (p<.05). The HIIE group exhibited significant improvements in the ankle and knee angles in the initial stance phase, SFI(p<.05). CONCLUSION: The state of such patients can be improved by applying the results of this study in that MIE and HIIE on a treadmill can contribute to the recovery of the peripheral nerve and motor skill. In particular, MIE is used as a walking functional training in the toe-off stance phase, while HIIE is suitable in the initial stance stage.