Transitional Zone Index and Intravesical Prostatic Protrusion in Benign Prostatic Hyperplasia Patients: Correlations according to Treatment Received and Other Clinical Data

Tao Huang,Jun Qi,YongJiang Yu,Ding Xu,Yang Jiao,Jian Kang,YunKai Zhu,YaQing Chen 대한비뇨의학회 2012 Investigative and Clinical Urology Vol.53 No.4

Purpose: The aim of this research was to assess the value of the transitional zone index (TZI) and intravesical prostatic protrusion (IPP) from transrectal ultrasonography in evaluating the severity and progression of disease by analyzing the relationship between the 2 parameters and symptoms, clinical history, and urodynamics in benign prostatic hyperplasia (BPH) patients undergoing different treatment. Materials and Methods: A total of 203 patients receiving medication and 162 patients who underwent transurethral resection of the prostate because of BPH were enrolled in this retrospective analysis. The clinical history and subjective and objective examination results of all patients were recorded and compared after being classified by TZI and IPP level. Linear regression was used to find correlations between IPP, TZI, and urodynamics. Results: The 2 parameters were found to differ significantly between patients receiving medication and patients undergoing surgical therapy (p<0.05). PSA, maximum flow rate (Qmax), detrusor pressure at Qmax (PdetQmax), and the bladder outlet obstruction index (BOOI) differed according to various TZI levels (p<0.05). In addition, the voiding symptom score, Qmax, and BOOI of subgroups with various IPP levels were also significantly different (p<0.05). Both TZI and IPP had significant effects on Qmax, BOOI, and PdetQmax (p<0.05) and the incidence of acute urinary retention (p=0.000). Conclusions: The results demonstrated that both TZI and IPP had favorable value for assessing severity and progression in patients with BPH. Further studies are needed to confirm whether the two parameters have predictive value in the efficacy of BPH treatment and could be considered as factors in the selection of therapy. Purpose: The aim of this research was to assess the value of the transitional zone index (TZI) and intravesical prostatic protrusion (IPP) from transrectal ultrasonography in evaluating the severity and progression of disease by analyzing the relationship between the 2 parameters and symptoms, clinical history, and urodynamics in benign prostatic hyperplasia (BPH) patients undergoing different treatment. Materials and Methods: A total of 203 patients receiving medication and 162 patients who underwent transurethral resection of the prostate because of BPH were enrolled in this retrospective analysis. The clinical history and subjective and objective examination results of all patients were recorded and compared after being classified by TZI and IPP level. Linear regression was used to find correlations between IPP, TZI, and urodynamics. Results: The 2 parameters were found to differ significantly between patients receiving medication and patients undergoing surgical therapy (p<0.05). PSA, maximum flow rate (Qmax), detrusor pressure at Qmax (PdetQmax), and the bladder outlet obstruction index (BOOI) differed according to various TZI levels (p<0.05). In addition, the voiding symptom score, Qmax, and BOOI of subgroups with various IPP levels were also significantly different (p<0.05). Both TZI and IPP had significant effects on Qmax, BOOI, and PdetQmax (p<0.05) and the incidence of acute urinary retention (p=0.000). Conclusions: The results demonstrated that both TZI and IPP had favorable value for assessing severity and progression in patients with BPH. Further studies are needed to confirm whether the two parameters have predictive value in the efficacy of BPH treatment and could be considered as factors in the selection of therapy.

Performance Comparison of Analytical Models for Rotor Eccentricity: A Case Study of Active Magnetic Bearing

Zhi Cao,Yunkai Huang,Baocheng Guo,Jianning Dong,Fei Peng 한국자기학회 2020 Journal of Magnetics Vol.25 No.2

This paper applies two different analytical methods, i.e., the perturbation method and superposition method, to calculate the magnetic flux density distribution and the magnetic force of the active magnetic bearing (AMB) with the rotor eccentricity. These two methods are thoroughly analyzed, compared and validated by the finite element model (FEM). The perturbation method is theoretically complex while the superposition method is intuitive. The valid range of the superposition method is larger than the perturbation method. However, the superposition method requires longer computation time. The main contribution of this paper is assessing the effectiveness of two analytical methods for predicting the AMB performance with the rotor eccentricity and giving a comprehensive guideline for engineers to choose the proper analytical method to design AMB.

A New Rotor Structure for High Speed Flywheel Permanent Magnet Synchronous Machine

Zichong Zhu,Yunkai Huang,Jianning Dong,Fei Peng 한국자기학회 2019 Journal of Magnetics Vol.24 No.3

This paper presents a new rotor design with assembled permeable retaining sleeve (APRS) to improve performances of a high speed permanent magnet synchronous machine (PMSM). The APRS consists of equal number of permeable and nonmagnetic parts, which are alternately arranged and assembled together circumferentially via keyways. Electromagnetic and mechanical characteristics of the rotor applied to a high speed flywheel PMSM are analyzed using finite element method. Machine performances are compared to an original design with commonly used rotor structure. It shows that phase inductance of the high speed machine increases dramatically due to smaller effective air gap, which may benefit suppressing inverter current harmonics. Also, permanent magnet usage reduces by 9.4 % to obtain identical back electromotive force and torque constant. In addition, a smaller skin depth owing to high-permeability material and the circumferential segmentation of the retaining sleeve effectively reduce rotor eddy current. Associated loss decreases by 40.7 % under open-circuit condition. A prototype rotor is fabricated and preliminary experimental tests are performed to confirm the analysis results.

An Improved Conformal Mapping Method for Static Angular Eccentricity Analysis of Axial Flux Permanent Magnet Machines

Baocheng Guo,Yunkai Huang,Fei Peng 한국자기학회 2018 Journal of Magnetics Vol.23 No.1

This paper presents an improved and simple analytical model to study the static angular eccentricity of single stator single rotor axial-flux permanent-magnet (AFPM) machine. The magnetic flux densities in the air gap under normal and static angular eccentricity are calculated by using a combination of Maxwell’s equations and Schwarz-Christoffel (SC) transformation. The original contribution of the model is that angular eccentricity is obtained without extra transformations. Thus the proposed approach is simpler than existing methods. The calculated back electromotive forces (EMFs) and cogging torque by the proposed method are compared with those obtained from the finite element (FE) model, the results show acceptable accuracy of the proposed method. In this way, the effectiveness of the proposed method is verified.

A Fast Analytic Model of Axial Flux Permanent Magnet Machines with Static/Dynamic Axis Eccentricity

Baocheng Guo,Yunkai Huang 한국자기학회 2016 Journal of Magnetics Vol.21 No.4

This paper presents a general analytical model to calculate the characteristics of axial-flux permanent-magnet machines with axis eccentricities. The radial and tangential magnetic flux densities in the air gap under normal conditions were first obtained using a combination of Maxwell’s equations and Schwarz-Christoffel (SC) transformation. Next, equations for the radii were deduced to investigate the static/dynamic eccentricities. The back electromotive forces (EMFs) were calculated and compared with those obtained from finite element (FE) analysis. The analytical predictions show good agreement with the FE results. Detection approaches were obtained by comparing with normal conditions, and the analytical model was verified experimentally.

Research on the Characteristics of AC Copper Loss and Suppression Method in Slotless Permanent Magnet Motor

Chenglong Chu,Yunkai Huang 한국자기학회 2023 Journal of Magnetics Vol.28 No.4

Due to the absence of magnetic teeth on the stator to restrict the magnetic field, the windings of the slotless motor are directly exposed to the air gap magnetic field. Consequently, this exposure results in a more irregular distribution of current in the windings and a notable increase in AC loss. Therefore, it is the key point in the design of slotless permanent magnet motor (SPMM) to study the characteristics of AC copper loss in detail and the effective suppression method. According to the structural characteristics of SPMM, this paper proposes to reduce the gap between wires (WDG) to reduce the AC copper loss. And the corresponding winding production method - winding extrusion potting (WEP) for toroidal windings is also introduced. In addition, the measurement method of WDG is demonstrated through experiments, and the accurate value of WDG before and after using this suppression method are obtained. The research results indicate a 46 % reduction in AC copper loss attributed to circulating current. Ultimately, the experimental outcomes of the prototype align well with the theoretical analysis and computational findings.

Variation Regularity of Key Performance Indexes Against the Slot Number of Tooth-Coil PMSMs

Zhu Zichong,Ge Wenjie,Mei Lei,Huang Yunkai 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.4

Tooth-coil permanent magnet synchronous machines (TC-PMSMs) are commonly used in wind power generation and wheelhub propulsion applications. These machines operate at low speeds and have a large number of poles and slots, providing various pole/slot combinations as options. Typically, these combinations have similar performances, making it challenging to choose the best one from diff erent perspectives. This study focuses on 32-pole TC-PMSMs with diff erent slot numbers to understand how key electromagnetic and thermal performance indicators vary with slot numbers. Using the fi nite element method, parameters such as torque density, cogging torque, inductance, fl ux-weakening capability, losses, and temperature rise are evaluated and compared. Prototypes of the wheel-hub TC-PMSM are manufactured and tested on a back-to-back test rig, to validate the analysis results. The fi ndings and conclusions derived from this research can assist in determining the optimal slot number or narrowing down the selection range of competitive pole/slot combinations during the scheme comparison stage.

Two-dimensional Harmonic Modelling for Electro-magnetic Solution in Cartesian Coordinates

Yunlu Du,Baocheng Guo,Z. Djelloul-khedda,Fei Peng,Yunkai Huang 한국자기학회 2022 Journal of Magnetics Vol.27 No.3

This paper first presents a general two-dimension (2D) harmonic analytical solution for the magnetic field of electric machines in the Cartesian coordinates. In this solution, the relative permeance is directly considered in Laplace and Poisson’s equations, and the particular solutions in Cartesian coordinates are solved. By applying the complex Fourier separation method, with the boundary and interface conditions, the magnetic field in the inhomogeneous region is solved from system equations. Numerical examples validate the presented method and the obtained results have a satisfactory agreement with the finite element analysis. The proposed model in this paper has a significant value for modelling electric machines, such as linear permanent magnet (PM) machines and axial flux PM machines.

Contact Parameter Computation and Analysis of Air Circuit Breaker with Permanent Magnet Actuator

Shuhua Fang,Heyun Lin,S. L. Ho,Xianbing Wang,Ping Jin,Yunkai Huang,Shiyou Yang 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.3

An air circuit breaker (ACB) with novel double-breaker contact and permanent magnet actuator (PMA) is presented. Three-dimensional (3-D) finite element method (FEM) is employed to compute the electro-dynamic repulsion forces, including the Holm force and Lorentz force, which are acting on the static and movable contacts. The electro-dynamic repulsion forces of different contact pieces are computed, illustrating there is an optimal number of contact pieces for the ACB being studied. The electro-dynamic repulsion force of each contact, which varies from the outer position to the inner position, is also computed. Finally, the contacts of the double-breaker are manufactured according to the analyzed results to validate the simulations.

Contact Parameter Computation and Analysis of Air Circuit Breaker with Permanent Magnet Actuator

Fang, Shuhua,Lin, Heyun,Ho, S.L.,Wang, Xianbing,Jin, Ping,Huang, Yunkai,Yang, Shiyou The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.3

An air circuit breaker (ACB) with novel double-breaker contact and permanent magnet actuator (PMA) is presented. Three-dimensional (3-D) finite element method (FEM) is employed to compute the electro-dynamic repulsion forces, including the Holm force and Lorentz force, which are acting on the static and movable contacts. The electro-dynamic repulsion forces of different contact pieces are computed, illustrating there is an optimal number of contact pieces for the ACB being studied. The electro-dynamic repulsion force of each contact, which varies from the outer position to the inner position, is also computed. Finally, the contacts of the double-breaker are manufactured according to the analyzed results to validate the simulations.