Design and analysis of mechanical flux‑weakening device of axial flux permanent magnet machines

Shaopeng Wang,Jiawei Lu,Bin Li,Chengcheng Liu,Youhua Wang,Gang Lei,Youguang Guo,Jianguo Zhu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.4

Due to the low inductance of an axial flux permanent magnet machine (AFPMM), the constant power speed regulation range is small. A new mechanical flux-weakening method for single-rotor single-stator AFPMMs is proposed in this paper. By installing a mechanical flux-weakening device on one side of the stator and rotating it certain angle, the speed regulation of the flux-weakening can be realized. The device is simple in structure, easy to operate, and can be operated in the process of machine operation. The validity of the device is verified by applying it to a machine. Finite-element software is used to calculate and analyze the performances of two machines with the device.

Multiphysical Design and Optimization of High-Speed Permanent Magnet Synchronous Motor with Sinusoidal Segmented Permanent Magnet Structure

Liu Chengcheng,Zhang Hongming,Wang Shaoheng,Wang Youhua,Lei Gang,Zhu Jianguo 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

High speed permanent magnet synchronous motor (HSPMSM) is an important driving motor for electric vehicles. Compared with the electric motor operated under normal speed, it is critical to reduce the torque ripple, vibration, and noise of the HSPMSM. Furthermore, The air-gap fux density total harmonic distortion and electromotive force total harmonic distortion determine by torque performance and vibration noise. This article uses analytical methods to analyze the infuence of permanent magnet sinusoidal segmentation (PMS) on the electromagnetic performance of surface-mounted HSPMSM. The fnite element method is used to calculate the infuence of diferent permanent magnet segmentation numbers, diferent adjacent permanent magnet decreasing thickness, and diferent center PM width on the electromagnetic performance of permanent magnet sinusoidal segmented surface-mounted high-speed permanent magnet synchronous motor (M2). Comparing the efectiveness of PMS in surface-mounted HSPMSM and interior HSPMSM. Furthermore, the rotor dynamics analysis and vibration noise analysis on M2 are performed, and the infuence of PMS on the stress and vibration noise of both motors’ rotors is summarized. This article proposes a parameter preprocessing grouping multiphysical multi-objective high-dimensional multilevel optimization method. Taking M2 as an example, a global optimization design was carried out for the high-dimensional structural parameters brought by PMS, which improved the electromagnetic performance of M2 and reduced the vibration noise and rotor stress.

Analysis of E-bike Trip Duration and Frequency by Bayesian Duration and Zero-inflated Count Models

Chengcheng Xu,Chen Wang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.4

E-bike trip duration and frequency are two essential variables to identify factors affecting e-bike travel demand. This study aimed to investigate the factors affecting e-bike trip duration and frequency. The Bayesian hazard-based duration models with random effect were developed to investigate the contributing factors to the travel time of e-bike trip. The random effect was included to capture the unobserved heterogeneity. Estimation results showed that trip purpose, traffic volume, population, departure time, age and occupation are the main contributing factors to e-bike trip duration. And the factors affecting travel time of e-bike trip are distinct between males and females. The validation results indicated that the predictive performance of the developed duration models are satisfactory. The Bayesian zero-inflated count models with random effect were then used to investigate the contributing factors to the e-bike trip frequency. The zero-inflated count model assumes that the frequency of e-bike trip is generated by two states, including zero-frequency state which determines whether people use e-bikes for travel, and negative binomial state which determines e-bike trip frequency.

Utilizing Structural Equation Modeling and Segmentation Analysis in Real-time Crash Risk Assessment on Freeways

Chengcheng Xu,Dawei Li,Zhibin Li,Wei Wang,Pan Liu 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.7

The study aimed to utilize Structural Equation Modeling (SEM) and K-means clustering for predicting real-time crash risks onfreeways. The SEM was used to transform a number of correlated traffic variables into four independent latent traffic factors, and toestablish the interrelationships among the traffic variables and crash risks. The segmentation analysis based on K-means clusteringwas then conducted to investigate the main traffic factors affecting crash risks in various traffic regimes. It was found that: (a) Themeasurement equations in SEM can effectively account for the correlations among traffic variables by transforming numerouscorrelated traffic variables into several latent traffic variables; (b) The SEM can both capture the direct and indirect effects of trafficflow variables on crash risks. This promotes a better understanding how traffic conditions affect crash risks; (c) The SEM producesmore accurate estimates of crash risks than existing modeling technique. It can increase the crash prediction accuracy by an averageof 7.6% compared with the commonly used logistic regression; and (d) Segmentation analysis results suggested that the trafficfactors contributing to crash risks are various across different traffic regimes. The proactive crash prevention strategies for differenttraffic regimes were discussed based on the findings in the segmentation analysis

TiO2 Nanotubes/Nanoparticles Composite Film with Higher Light Harvesting and Electron Transfer for Dye-Sensitized Solar Cells

Chengcheng Liu,Zhifeng Liu,Lei E,Yabin Li,Jianhua Han,Yun Wang,Zhichao Liu,Jing Ya,Xuhuang Chen 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.5

TiO2 nanotubes with an inner diameter of 4-6 nm were synthesized by hydrothermal treatment method. TiO2nanotubes/nanoparticles composite films were fabricated as a dye-sensitized solar cells work electrode using TiO2 nanotubes and TiO2 nanoparticles as precursor. The structure of composite films has a remarkable influence on the final performance of the cell due to high surface area, fast electron transfer, enhanced light-scattering and light-harvesting, simultaneously. I-V characteristic measurement indicates an enhanced efficiency by 27%as compared to TiO2 nanotubes film.

Development of a Crash Risk Index to Identify Real Time Crash Risks on Freeways

Chengcheng Xu,Pan Liu,Wei Wang,Xuan Jiang 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.7

The primary objective of this study is to develop a quantitative indicator that can be directly used to identify hazardous traffic states on freeway mainlines. Using data obtained from a 22-mile freeway segment on the I-880N freeway in San Francisco Bay Area in the United States, Fisher discriminant analysis was conducted to derive a linear combination of traffic flow parameters which can be used to distinguish traffic states which may lead to crashes from normal traffic conditions which were potentially safe. A new variable termed “crash risk index” was defined based on the discriminant function. A crash risk index which is smaller than 0 represents a hazardous traffic condition potentially leading to a crash. Accordingly, a crash risk index which is greater than 0 represents normal traffic conditions which, theoretically, will not lead to crash occurrences. The research team tested the prediction performance of using the crash risk index to identify hazardous traffic conditions on freeway mainlines. An overall prediction accuracy of about 65.7% was achieved. Conditional logistic regression analysis was then conducted to evaluate the impacts of crash risk indexes on the likelihood of crash occurrences. It was found that the likelihood of freeway crashes increased with the decreases in crash risk index. One unit decrease in crash risk index increased the risk of crash occurrence by 180.3%. The research team also looked extensively at the impacts of crash risk indexes at different time slices. It was found that the impacts of crash risk index decrease with time and the crash risk index at the time slice most immediately before crashes had the greatest impact on crash occurrences.

Clinicopathological Analysis and Treatment of Adult Patients with Inflammatory Myofibroblastic Tumor: A 15-Year Single- Center Study

Xin Liu,Chengcheng Gong,Jieyun Zhang,Wanjing Feng,Yanjing Guo,Youzhou Sang,Chunmeng Wang,Yong Chen,Jian Wang,Lin Yu,Xiaowei Zhang,Zhiguo Luo 대한암학회 2023 Cancer Research and Treatment Vol.55 No.3

Purpose Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal malignancy that occurs primarily in children and adolescents. The clinical and pathological features of IMT in adult patients are not well understood.Materials and Methods We retrospectively searched for records of adult patients with IMT at Fudan University Shanghai Cancer Center from 2006 to 2021. Clinicopathological data, treatments, and outcomes were collected and analyzed.Results Thirty adult patients with IMT, mostly women (60.0%), were included. The median age of the patients was 38 (21-77). The most common primary site was abdominopelvic region (53.3%), followed by lungs (20.0%). Seven patients had an abdominal epithelioid inflammatory myofibroblast sarcoma (EIMS). The positivity rate of anaplastic lymphoma kinase (ALK) was 81.5% (22/27). Sixteen patients with advanced ALK-positive disease received crizotinib, with an objective response rate (ORR) of 81.3% and a disease control rate of 87.5%. The median progression-free survival was 20.8 months. EIMS was associated with more aggressive behavior; however, the prognosis was similar to that of non-EIMS patients after treatment with an ALK inhibitor. At a median follow-up time of 30 months (95% confidence interval [CI], 13.6 to 46.4), the 5-year overall survival was 77% (95% CI, 66 to 88) in all patients.Conclusion Adult IMTs appeared more aggressive, with a higher incidence of recurrence and metastases, and patients with EIMS had more aggressive cases. Treatment with ALK inhibitors resulted in a high ORR and a durable response, which suggested that ALK inhibitors could be used as a first-line treatment option in adult patients with ALK-positive advanced IMT.

Molecular detection and genetic diversity of bovine papillomavirus in dairy cows in Xinjiang, China

Qingling Meng,Chengcheng Ning,Lixia Wang,Yan Ren,Jie Li,Chencheng Xiao,Yanfang Li,Zhiyuan Li,Zhihao He,Xuepeng Cai,Jun Qiao 대한수의학회 2021 Journal of Veterinary Science Vol.22 No.4

Background: Bovine papillomatosis is a type of proliferative tumor disease of skin and mucosae caused by bovine papillomavirus (BPV). As a transboundary and emerging disease in cattle, it poses a potential threat to the dairy industry. Objectives: The aim of this study is to detect and clarify the genetic diversity of BPV circulating in dairy cows in Xinjiang, China. Methods: 122 papilloma skin lesions from 8 intensive dairy farms located in different regions of Xinjiang, China were detected by polymerase chain reaction. The genetic evolution relationships of various types of BPVs were analyzed by examining this phylogenetic tree. Results: Ten genotypes of BPV (BPV1, BPV2, BPV3, BPV6, BPV7, BPV8, BPV10, BPV11, BPV13, and BPV14) were detected and identified in dairy cows. These were the first reported detections of BPV13 and BPV14 in Xinjiang, Mixed infections were detected, and there were geographical differences in the distribution of the BPV genotypes. Notably, the BPV infection rate among young cattle (< 1-year-old) developed from the same supply of frozen sperm was higher than that of the other young cows naturally raised under the same environmental conditions. Conclusions: Genotyping based on the L1 gene of BPV showed that BPVs circulating in Xinjiang China displayed substantial genetic diversity. This study provided valuable data at the molecular epidemiology level, which is conducive to developing deep insights into the genetic diversity and pathogenic characteristics of BPVs in dairy cows.

Conservative therapy with metformin plus megestrol acetate for endometrial atypical hyperplasia

Weiwei Shan,Chao Wang,Zhenbo Zhang,Chao Gu,Chengcheng Ning,Xuezhen Luo,Qiongjie Zhou,Xiaojun Chen 대한부인종양학회 2014 Journal of Gynecologic Oncology Vol.25 No.3

Objective: To compare the efficacy of metformin plus megestrol acetate (MA) with that of MA alone for treating endometrial atypical hyperplasia (EAH). Methods: This pilot study included 16 EAH patients who met at least one metabolic syndrome (MS) criterion and received either adjunctive metformin plus MA (MET group) or MA monotherapy (MA group). Each patient in the MA group received 160 mg of MA daily, whereas patients in the MET group received the same dose of MA plus 0.5 g of metformin thrice daily. Treatment response was assessed by histological examination of dilation and curettage specimens obtained after 12 weeks of therapy. Results: Each group had eight patients, and half of the patients in each group were diagnosed with MS. The complete response (CR) rate was 75% (6/8) in the MET group and 25% (2/8) in the MA group (p=0.105). Complications of MS did not affect the response rates in either group. In the MET group, 75% (3/4) of the patients had CR in the presence or absence of MS. In the MA group, 50% (2/4) of the patients with MS had CR, whereas no patient without MS had CR. No irreversible toxicities were observed. Conclusion: Metformin plus MA may be a potential alternative therapy for treating EAH, and the MS status of patients may have no effect on the efficacy of metformin plus MA therapy.

Hyperbranched Electroactive Azo Polyamide Based on Oligoaniline: Synthesis, Characterization, and Dielectric Properties

Xiaoteng Jia,Ce Wang,Danming Chao,Libing He,Hongtao Liu,Tian Zheng,Chengcheng Zhang 한국고분자학회 2011 Macromolecular Research Vol.19 No.11

A novel hyperbranched electroactive azo polyamide containing oligoaniline was synthesized by oxidative coupling polymerization. The detailed characteristics of the obtained polyamide were systematically studied by Fourier transform infrared (FTIR) spectra, nuclear magnetic resonance (^1H NMR) spectroscopy, and gel permeation chromatography (GPC). The thermogravimetric analysis (TGA) revealed a good thermal resistance of the polymer. The photoisomerization process and doping process of the polymer were monitored with ultraviolet-visible spectroscopy. Further, the electrochemical behavior of the polymer was explored by cyclic voltammogram (CV), and the mechanism of electrochemical oxidation process was studied in detail. The polymer in the HCl-doped form possessed much higher dielectric constants compared with that of the similar linear polymer reported before, mainly due to the highly branched three-dimensional molecular architecture and the high content of oligoaniline segments.