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Control of Electrically Excited Synchronous Motors with a Low Switching Frequency
Yuan, Qing-Qing,Wu, Xiao-Jie,Dai, Peng,Fu, Xiao The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.4
The switching frequency of the power electronic devices used in large synchronous motor drives is usually kept low (less than 1 kHz) to reduce the switching losses and to improve the converter power capability. However, this results in a couple of problems, e.g. an increase in the harmonic components of the stator current, and an undesired cross-coupling between the magnetization current component ($i_m$) and the torque component ($i_t$). In this paper, a novel complex matrix model of electrically excited synchronous motors (EESM) was established with a new control scheme for coping with the low switching frequency issues. First, a hybrid observer was proposed to identify the instantaneous fundamental component of the stator current, which results in an obvious reduction of both the total harmonic distortion (THD) and the low order harmonics. Then, a novel complex current controller was designed to realize the decoupling between $i_m$ and $i_t$. Simulation and experimental results verify the effectiveness of this novel control system for EESM drives.
Yuan, Zi-Xu,Ma, Teng-Hui,Zhong, Qing-Hua,Wang, Huai-Ming,Yu, Xi-Hu,Qin, Qi-Yuan,Chu, Li-Li,Wang, Lei,Wang, Jian-Ping Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.2
Radiation proctitis is a common complication after radiotherapy for pelvic malignant tumors. This study was conducted to assess the efficacy of novel almagate enemas in hemorrhagic chronic radiation proctitis (CRP) and evaluate risk factors related to rectal deep ulcer or fistula secondary to CRP. All patients underwent a colonoscopy to confirm the diagnosis of CRP and symptoms were graded. Typical endoscopic and pathological images, risk factors, and quality of life were also recorded. A total of 59 patients were enrolled. Gynecological cancers composed 93.1% of the primary malignancies. Complete or obvious reduction of bleeding was observed in 90% (53/59) patients after almagate enema. The mean score of bleeding improved from 2.17 to 0.83 (P<0.001) after the enemas. The mean response time was 12 days. No adverse effects were found. Moreover, long-term successful rate in controlling bleeding was 69% and the quality of life was dramatically improved (P=0.001). The efficacy was equivalent to rectal sucralfate, but the almagate with its antacid properties acted more rapidly than sucralfate. Furthermore, we firstly found that moderate to severe anemia was the risk factor of CRP patients who developed rectal deep ulcer or fistulas (P= 0.015). We also found abnormal hyaline-like thick wall vessels, which revealed endarteritis obliterans and the fibrosis underlying this disease. These findings indicate that almagate enema is a novel effective, rapid and well-tolerated method for hemorrhagic CRP. Moderate to severe anemia is a risk factor for deep ulceration or fistula.
Qing-Yuan Xu,Jing Cheng,Yun-Shan Wei,Kai Wan 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.9
In this paper, an adaptive iterative learning control (ILC) design method is proposed for a class of nonlinear discrete-time systems with nonaffine structure, randomly varying trail length, and uncertain control direction. In order to achieve repetitive tracking control of the nonaffine structure systems with uncertain control direction, randomly varying trail length, and other uncertainties, we apply a high-order neural network to approximate the expected system input. Then, a novel adaptation law is designed for the neural network weight vector. The main feature of the method proposed in this paper is that the weight vector norm instead of the weight vector itself is updated iteratively to realize the successive approximation of the expected system input, the custom-designed identification mechanism is not necessary to deal with the uncertain control direction, and the analysis of randomly varying trail lengths problem is strictly established. The convergence of the proposed adaptive ILC is set up by a composite energy function. The effectiveness of the proposed adaptive ILC design is validated by two simulation examples.
Qing Yuan,Shihong Zhai,Li Wu,Peishuai Chen,Yuchun Zhou,Qingjun Zuo 한국자원공학회 2019 Geosystem engineering Vol.22 No.5
In blasting excavation engineering of super-large section underground caverns, blasting vibration velocity prediction accuracy is affected by many factors. In order to improve its accuracy, the key problem is to obtain these affect factors comprehensively. In this paper, we innovatively put forward eight independent factors in the aspect of explosion source conditions, engineering conditions and propagation medium conditions. These factors have complex non-linear relationship with blasting vibration velocity. We consider particle swarm optimization (PSO) algorithm and least squares support vector machine (LS-SVM) method for prediction (PSO-LSSVM). In this way, how to determine the characteristic parameters and calculation rules of PSO-LSSVM method is another key problem, which has been innovatively solved in this paper. Then it is used to predict the blasting vibration velocity of underground water-sealed LPG caverns in Yantai, China, and compared with Sadov’s formula (SA), fuzzy neural network (FNN) and LS-SVM methods. The results indicate that relative errors of PSO-LSSVM are significantly less than LS-SVM, FNN and SA. Whether global root mean square relative error for prediction accuracy, or group number meeting requirement of error threshold value for generalization performance, the PSO-LSSVM method is superior to LS-SVM, FNN and SA with best availability and superiority.
CONVERGENCE OF ISHIKAWA ITERATION WITH ERROR TERMS ON AN ARBITRARY INTERVAL
Yuan, Qing,Cho, Sun-Young,Qin, Xiaolong Korean Mathematical Society 2011 대한수학회논문집 Vol.26 No.2
In this paper, a continuous real function on the real line is considered. The necessary and sufficient conditions for the convergence of the Ishikawa iteration with error terms for the functional are obtained.
( Qing Zhang ),( Jie Wang ),( Qing Sun ),( Shu-ming Zhang ),( Xiang-yang Sun ),( Chan-yuan Li ),( Miao-xin Zheng ),( Wen-liang Xiang ),( Jie Tang ) 한국미생물 · 생명공학회 2021 Journal of microbiology and biotechnology Vol.31 No.8
A released exopolysaccharide (rEPS)-producing strain (LM187) with good acid resistance, bile salt resistance, and cholesterol-lowering properties was isolated from Sichuan paocai and identified as Leuconostoc mesenteroides subsp. mesenteroides. The purified rEPS, designated as rEPS414, had a uniform molecular weight of 7.757 × 10<sup>5</sup> Da. Analysis of the monosaccharide composition revealed that the molecule was mainly composed of glucose. The Fourier transform-infrared spectrum showed that rEPS414 contained both α-type and β-type glycosidic bonds. <sup>1</sup>H and <sup>13</sup>C nuclear magnetic resonance spectra analysis showed that the purified rEPS contained arabinose, galactose, and rhamnose, but less uronic acid. Scanning electron microscopy demonstrated that the exopolysaccharide displayed a large number of scattered, fluffy, porous cellular network flake structures. In addition, rEPS414 exhibited strong in vitro antioxidant activity. These results showed that strain LM187 and its rEPS are promising probiotics with broad prospects in industry.
( Yuan-qing Hu ),( Xian-hui Huang ),( Li-qing Guo ),( Zi-chen Shen ),( Lin-xue Lv ),( Feng-xia Li ),( Zan-hu Zhou ),( Dan-feng Zhang ) 한국미생물 · 생명공학회 2021 Journal of microbiology and biotechnology Vol.31 No.12
Vibrio parahaemolyticus is recognized as one of the most important foodborne pathogens responsible for gastroenteritis in humans. The bla<sub>CARB-17</sub> gene is an intrinsic β-lactamase gene and a novel species-specific genetic marker of V. parahaemolyticus. In this study, a loop-mediated isothermal amplification (LAMP) assay combined with a lateral flow dipstick (LFD) was developed targeting this bla<sub>CARB-17</sub> gene. The specificity of LAMP-LFD was ascertained by detecting V. parahaemolyticus ATCC 17802 and seven other non-V. parahaemolyticus strains. Finally, the practicability of LAMP-LFD was confirmed by detection with V. parahaemolyticus-contaminated samples and natural food samples. The results showed that the optimized reaction parameters of LAMP are as follows: 2.4 mmol/l Mg<sup>2+</sup>, 0.96 mmol/l dNTPs, 4.8 U Bst DNA polymerase, and an 8:1 ratio of inner primer to outer primer, at 63℃ for 40 min. The optimized reaction time of the LFD assay is 60 min. Cross-reactivity analysis with the seven non-V. parahaemolyticus strains showed that LAMP-LFD was exclusively specific for V. parahaemolyticus. The detection limit of LAMP-LFD for V. parahaemolyticus genomic DNA was 2.1 × 10<sup>-4</sup> ng/μl, corresponding to 630 fg/reaction and displaying a sensitivity that is 100-fold higher than that of conventional PCR. LAMP-LFD in a spiking study revealed a detection limit of approximately 6 CFU/ml, which was similar with conventional PCR. The developed LAMP-LFD specifically identified the 10 V. parahaemolyticus isolates from 30 seafood samples, suggesting that this LAMP-LFD may be a suitable diagnostic method for detecting V. parahaemolyticus in aquatic foods.