Solution to Some Key Problems of Self-exciting Electronic Ballast

Peng Mao,Weiping Zhang,Mao Zhang 한국전기전자재료학회 2014 Transactions on Electrical and Electronic Material Vol.15 No.1

Self-exciting electronic ballast, of small size, and low cost, and high power, with no stroboscopic effect, no noise,is widely used in the general lighting market. This paper describes the cause of high switching loss of self-excitingelectronic ballast, based on its operational principle; then, to reduce the switch temperature and increase thereliability of the product, the drive circuit has been improved, to achieve soft-switching. The theory analysis,simulation and experimental result prove the feasibility and compatibility of this new method in practice. Finally, thedesign procedure and winding method of the self-exciting current transformer are introduced.

A Canonical Small-Signal Linearized Model and a Performance Evaluation of the SRF-PLL in Three Phase Grid Inverter System

Mao, Peng,Zhang, Mao,Zhang, Weiping The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.5

Phase-locked loops (PLL) based on the synchronous reference frame (SRF-PLL) have recently become the most widely-used for grid synchronization in three phase grid-connected inverters. However, it is difficult to study their performance since they are nonlinear systems. To estimate the performances of a SRF-PLL, a canonical small-signal linearized model has been developed in this paper. Based on the proposed model, several significant specifications of a SRF-PLL, such as the capture time, capture rang, bandwidth, the product of capture time and bandwidth, and steady-state error have been investigated. Finally, a noise model of a SRF-PLL has been put forward to analyze the noise rejection ability by computing the SNR (signal-to-noise ratio) of a SRF-PLL. Several simulation and experimental results have been provided to verify and validate the obtained conclusions. Although the proposed model and analysis method are based on a SRF-PLL, they are also suitable for analyzing other types of PLLs.

A Field Theory Based Model for Identifying the Effect of Organizational Structure on the Formation of Organizational Culture in Construction Projects

Peng Mao,Shuai Li,Kunhui Ye,Hubo Cai 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.1

A carefully selected organizational structure paves the way for the success of a construction project by fostering a strong and enduring organizational culture. However, very little research has been conducted regarding the effect of organizational structure on the formation of organizational culture. This research employs the field theory to demonstrate organizational culture development and thereafter proposes a novel model for identifying the effect of organizational structure on the formation of organizational culture in a construction project. An empirical analysis based on the Chinese construction industry is performed to verify the proposed model. The primary contribution of this research is twofold. First, it presents a new perspective of examining organizational culture development from organizational structure by using the cultural field theory. Second, it reveals the important effect of organizational structure on the formation of organizational culture and offers project owners a new approach for identifying the effect which could also be a reference for further selecting an appropriate organizational structure.

Solution to Some Key Problems of Self-exciting Electronic Ballast

Mao, Peng,Zhang, Weiping,Zhang, Mao The Korean Institute of Electrical and Electronic 2014 Transactions on Electrical and Electronic Material Vol.15 No.1

Self-exciting electronic ballast, of small size, and low cost, and high power, with no stroboscopic effect, no noise, is widely used in the general lighting market. This paper describes the cause of high switching loss of self-exciting electronic ballast, based on its operational principle; then, to reduce the switch temperature and increase the reliability of the product, the drive circuit has been improved, to achieve soft-switching. The theory analysis, simulation and experimental result prove the feasibility and compatibility of this new method in practice. Finally, the design procedure and winding method of the self-exciting current transformer are introduced.

A Canonical Small-Signal Linearized Model and a Performance Evaluation of the SRF-PLL in Three Phase Grid Inverter System

Peng Mao,Mao Zhang,Weiping Zhang 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.5

Phase-locked loops (PLL) based on the synchronous reference frame (SRF-PLL) have recently become the most widely-used for grid synchronization in three phase grid-connected inverters. However, it is difficult to study their performance since they are nonlinear systems. To estimate the performances of a SRF-PLL, a canonical small-signal linearized model has been developed in this paper. Based on the proposed model, several significant specifications of a SRF-PLL, such as the capture time, capture rang, bandwidth, the product of capture time and bandwidth, and steady-state error have been investigated. Finally, a noise model of a SRF-PLL has been put forward to analyze the noise rejection ability by computing the SNR (signal-to-noise ratio) of a SRF-PLL. Several simulation and experimental results have been provided to verify and validate the obtained conclusions. Although the proposed model and analysis method are based on a SRF-PLL, they are also suitable for analyzing other types of PLLs.

Analysis and Improvement on Input Characteristics of VIENNA Converter with Inductive Filter and One-Cycle-Control Method

A. Peng Mao,B. Shaojun Xie,C. Hongyun Jia,D. Yonghong Zhang,E. Jinming Xu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Input characteristics of L-filtered pulse-width-modulation (PWM) converter with one-cycle-control (OCC) method was analyzed, and the contradiction between decreasing phase displacement angle and decreasing input current ripple was revealed when the maximum switching frequency was limited to ensure high system efficiency. Given this, LCL-filtering scheme was introduced and used on OCC PWM converter, and the inductor current sampling scheme was proposed combined with frequency domain analysis of the system. Finally, experimental results were given to prove validity of the provided filtering scheme and the current sampling strategy.

Multicriteria Optimization via Parameter Space Investigation for Ultralow-Altitude Airdrop L1 Adaptive Controller

Peng Zhu,Wen-han Dong,Yuhao Mao,Ri Liu 한국항공우주학회 2020 International Journal of Aeronautical and Space Sc Vol.21 No.1

This paper presents preliminary results of the application of the parameter space investigation method for the design of the L1 flight control system implemented on the ultralow-altitude airdrop process. In particular, the study has established the task performance level of airdrop mission which is chosen as the optimization objective in this paper. According to the characteristics of ultralow-altitude airdrop process, 12 optimization criteria are designated as the constraints during the multicriteria optimization. After two iterations, the task performance level of the airdrop is improved from “Moderate” to “Expected”. The results in the paper confirms the suitability of the parameter space investigation method for the multicriteria design optimization of an airdrop flight control system subject to desired control specifications. In addition, the robustness and dynamic response of the flight control system are significantly improved after optimization. Moreover, the analysis of optimization results has contributed to a deeper understanding of the relationship between L1 controller parameters and airdrop task performance.

SIRT5-related desuccinylation modification of AIFM1 protects against compression-induced intervertebral disc degeneration by regulating mitochondrial homeostasis

Mao Jianxin,Wang Di,Wang Dong,Wu Qi,Shang Qiliang,Gao Chu,Wang Huanbo,Wang Han,Du Mu,Peng Pandi,Jia Haoruo,Xu Xiaolong,Wang Jie,Yang Liu,Luo Zhuojing 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Mitochondrial dysfunction plays a major role in the development of intervertebral disc degeneration (IDD). Sirtuin 5 (SIRT5) participates in the maintenance of mitochondrial homeostasis through its desuccinylase activity. However, it is still unclear whether succinylation or SIRT5 is involved in the impairment of mitochondria and development of IDD induced by excessive mechanical stress. Our 4D label-free quantitative proteomic results showed decreased expression of the desuccinylase SIRT5 in rat nucleus pulposus (NP) tissues under mechanical loading. Overexpression of Sirt5 effectively alleviated, whereas knockdown of Sirt5 aggravated, the apoptosis and dysfunction of NP cells under mechanical stress, consistent with the more severe IDD phenotype of Sirt5 KO mice than wild-type mice that underwent lumbar spine instability (LSI) surgery. Moreover, immunoprecipitation-coupled mass spectrometry (IP-MS) results suggested that AIFM1 was a downstream target of SIRT5, which was verified by a Co-IP assay. We further demonstrated that reduced SIRT5 expression resulted in the increased succinylation of AIFM1, which in turn abolished the interaction between AIFM1 and CHCHD4 and thus led to the reduced electron transfer chain (ETC) complex subunits in NP cells. Reduced ETC complex subunits resulted in mitochondrial dysfunction and the subsequent occurrence of IDD under mechanical stress. Finally, we validated the efficacy of treatments targeting disrupted mitochondrial protein importation by upregulating SIRT5 expression or methylene blue (MB) administration in the compression-induced rat IDD model. In conclusion, our study provides new insights into the occurrence and development of IDD and offers promising therapeutic approaches for IDD.

From Nanodot to Nanowire: Hybrid Au/Titania Nanoarrays by Block Copolymer Templates

Peng, Juan,Mao, Chun,Kim, Jinheung,Kim, Dong Ha WILEY-VCH Verlag 2009 Macromolecular Rapid Communications Vol.30 No.21

<P>A simple scheme to fabricate 2-D arrays of Au/titania hybrid nanopatterns is presented, using polystyrene-block-poly(ethylene oxide) diblock copolymer (PS-b-PEO) as templates coupled with sol–gel chemistry. Both the functionalized Au nanoparticles (NPs) and titania precursors are selectively incorporated into the PEO domain. A series of morphologies ranging from nanodot to nanowire arrays is formed and the mechanism of morphological evolution is discussed. Such hybrid films exhibit characteristic localized surface plasmon resonance bands originating from the coupling between neighboring Au NPs spatially located in a controlled manner.</P><P> <img src='wiley_img/10221336-2009-30-21-MARC200900209-gra001.gif' alt='wiley_img/10221336-2009-30-21-MARC200900209-gra001'> </P> <B>Graphic Abstract</B> <P>A simple route to fabricate 2-D arrays of Au/TiO2 hybrid nanopatterns is presented, using polystyrene-block-poly(ethylene oxide) diblock copolymer as templates coupled with sol–gel chemistry. A series of morphologies ranging from nanodot to nanowire arrays is formed. Such hybrid films exhibit characteristic localized surface plasmon resonance bands originating from the coupling between neighboring Au nanoparticles spatially located in a controlled manner. <img src='wiley_img/10221336-2009-30-21-MARC200900209-content.gif' alt='wiley_img/10221336-2009-30-21-MARC200900209-content'> </P>

The Predictive Value of Magnetic Resonance Imaging-based Texture Analysis in Evaluating Histopathological Grades of Breast Phyllodes Tumor

Yifei Mao,Zhongtang Xiong,Songxin Wu,Zhiqing Huang,Ruoxian Zhang,Yuqin He,Yuling Peng,Yang Ye,Tianfa Dong,Hui Mai 한국유방암학회 2022 Journal of breast cancer Vol.25 No.2

Purpose: Knowing the distinction between benign and borderline/malignant phyllodes tumors (PTs) can help in the surgical treatment course. Herein, we investigated the value of magnetic resonance imaging-based texture analysis (MRI-TA) in differentiating between benign and borderline/malignant PTs. Methods: Forty-three women with 44 histologically proven PTs underwent breast MRI before surgery and were classified into benign (n = 26) and borderline/malignant groups (n = 18 [15 borderline, 3 malignant]). Clinical and routine MRI parameters (CRMP) and MRI-TA were used to distinguish benign from borderline/malignant PT. In total, 298 texture parameters were extracted from fat-suppression (FS) T2-weighted, FS unenhanced T1-weighted, and FS first-enhanced T1-weighted sequences. To evaluate the diagnostic performance, receiver operating characteristic curve analysis was performed for the K-nearest neighbor classifier trained with significantly different parameters of CRMP, MRI sequence-based TA, and the combination strategy. Results: Compared with benign PTs, borderline/malignant ones presented a higher local recurrence (p = 0.045); larger size (p < 0.001); different time-intensity curve pattern (p = 0.010); and higher frequency of strong lobulation (p = 0.024), septation enhancement (p = 0.048), cystic component (p = 0.023), and irregular cystic wall (p = 0.045). TA of FS T2- weighted images (0.86) showed a significantly higher area under the curve (AUC) than that of FS unenhanced T1-weighted (0.65, p = 0.010) or first-enhanced phase (0.72, p = 0.049) images. The texture parameters of FS T2-weighted sequences tended to have a higher AUC than CRMP (0.79, p = 0.404). Additionally, the combination strategy exhibited a similar AUC (0.89, p = 0.622) in comparison with the texture parameters of FS T2-weighted sequences. Conclusion: MRI-TA demonstrated good predictive performance for breast PT pathological grading and could provide surgical planning guidance. Clinical data and routine MRI features were also valuable for grading PTs.