The Experts below are selected from a list of 12180 Experts worldwide ranked by ideXlab platform

Hyung Jun Park - One of the best experts on this subject based on the ideXlab platform.

Kimo Jang - One of the best experts on this subject based on the ideXlab platform.

Seung Beom Han - One of the best experts on this subject based on the ideXlab platform.

  • unintended rotational changes of the distal tibia after biplane medial open wedge high tibial osteotomy
    Journal of Arthroplasty, 2016
    Co-Authors: Kimo Jang, Hyung Jun Park, Jong Hee Lee, Jeong Lae Kim, Seung Beom Han
    Abstract:

    This study involved 35 knees undergoing biplane medial open-wedge high tibial osteotomy (OWHTO) to assess the axial rotation of the distal tibia. The distal tibiae were internally rotated by 3.0° ± 7.1° after OWHTO. The Opening Width showed a Pearson correlation coefficient of -0.743 (P < .001), and the tuberosity osteotomy angle showed that of -0.678 (P < .001) with distal tibial rotation. However, changes in hip-knee-ankle angle, medial proximal tibial angle, and posterior tibial slope were not significantly correlated with the change in distal tibial rotation. In conclusion, there was an unintended tendency of increasing internal rotation of the distal tibia after biplane medial OWHTO, and this tendency was positively related to the Opening Width and tuberosity osteotomy angle.

Fu Lin - One of the best experts on this subject based on the ideXlab platform.

  • reduction of vibration and acoustic noise in permanent magnet synchronous motor by optimizing magnetic forces
    Journal of Sound and Vibration, 2018
    Co-Authors: Fu Lin, Shuguang Zuo, Wenzhe Deng
    Abstract:

    Abstract Two methodologies are proposed in this paper to reduce electromagnetic vibration and noise of permanent magnet synchronous motor. A multiphysics model is firstly established to predict the vibration and noise. Experimental tests are conducted to validate the model. Then, the source of the vibration and noise peaks from calculated and tested results is located. Two methodologies are proposed to mitigate this source. One is by reducing its amplitude through adjusting slot Opening Width and magnet shape. The other is by changing the phase of the specific force harmonic along the axial direction through stepwise or continuous magnet skewing. The optimum skewing angle is analytically derived. Based on the validated multiphysics model, optimizations under different methods are compared. It is found that considerable reductions of noise can be achieved by reducing low space harmonics of radial force. In particular, to reduce the noise over a wide frequency band, magnet skewing is a better solution than optimizing slot Opening Width and magnet shape.

  • noise analysis calculation and reduction of external rotor permanent magnet synchronous motor
    IEEE Transactions on Industrial Electronics, 2015
    Co-Authors: Shuguang Zuo, Fu Lin
    Abstract:

    A detailed analysis of electromagnetic noise in external rotor permanent-magnet synchronous motors is presented in this paper. First, the spatial distribution and frequency characteristics of the electromagnetic force acting on the surface of the permanent magnet are discussed. Then, calculation models for electromagnetic force, structural vibration, and acoustic radiation are developed to predict noise by taking an external rotor in-wheel motor as example. The uneven distribution of electromagnetic force on the surface of the permanent magnet is taken into account by means of loading nodal force into the structural model which is verified by modal test. Through the mode superposition method, the vibration on the surface of the outer rotor is calculated, and the acoustic boundary element method is used to predict the acoustic radiation. Noise test is conducted to validate the simulated noise. It is shown in both simulation results and noise test that the electromagnetic force due to slotting effects contributes the most remarkable component to the overall noise. Finally, slot Opening Width is optimized to reduce the amplitude of magnetic force close to resonance frequencies, and the overall sound pressure level decreases by 6 dB(A) after optimization.

Yanxia Li - One of the best experts on this subject based on the ideXlab platform.

  • combined auxiliary entrainment and structure optimization for performance improvement of steam ejector with consideration of back pressure variation
    Energy Conversion and Management, 2018
    Co-Authors: Yongzhi Tang, Yanxia Li
    Abstract:

    Abstract It is crucial to enhance the entrainment performance of steam ejectors which operate under double-critical conditions to widen their application in industries. In this paper, combined auxiliary entrainment technical approach is proposed and corresponding geometric structure optimization has implemented systematically, for a better use of the inside low-pressure potential thus greatly improving the entrainment performance of the steam ejector under double-critical conditions. Moreover, a comprehensive analysis and discussion of the influence of the geometrical parameters on the auxiliary entrainment performance has been obtained from mass flow rate, pressure field and special internal flow characteristics. The results reveal that the combined auxiliary entrainment is the best choice for the given steam ejector operating under the double-critical conditions, and the optimum geometrical parameters of throat auxiliary entraining entrance are same as the designed condition and remain unchanged. For the diffuser auxiliary entraining entrance, the Opening starting position Xs could be set at the entrance of the diffuser identically, the Opening angle could be chosen as a common range Rθ from 75° to 105°. However, the optimum Opening Width d increases with the decrease of back pressure pC. In general, there is an optimum geometrical parameters combination that the entrainment performance can achieve its maximum value for each pC. The smaller the pC, the bigger the entrainment ratio improvement, as large as 34.8% for pC of 32 kPa.

  • performance improvement of steam ejectors under designed parameters with auxiliary entrainment and structure optimization for high energy efficiency
    Energy Conversion and Management, 2017
    Co-Authors: Yongzhi Tang, Yanxia Li, Hongqiang Wu
    Abstract:

    Abstract Steam ejectors are regarded as a promising energy-saving technology, which have been widely used in many industries. The aim of this paper is to optimize the geometrical parameters of the auxiliary entraining entrance that has a significant influence on the entrainment performance. In this study, the developed auxiliary entrainment and structure optimization make good use of the low-pressure potential inside the throat for performance improvement. Moreover, the influence of auxiliary entraining entrance geometric parameters on internal flow fields and mass flow rate have been obtained numerically and analyzed carefully, and the special internal flow characteristics are also presented and discussed in detail to emphasize the role of auxiliary entraining entrance geometric parameters in determining entrainment performance. The results reveal that the major influence factors of entrainment performance are the effective suction pressure area, the near-wall mixed steam velocity and the negative affect on main entraining entrance. And there are an optimum geometrical parameters combination of the auxiliary entraining entrance, whose Opening center position is 119mm, Opening Width is 5 mm and Opening angle is 90° for the given ejector and operation parameters, with a maximum entrainment ratio improvement of 3.80% comparing with that of the conventional designed steam ejector. Furthermore, the auxiliary entraining entrance can be designed in an appropriate range.