Analysis and Design of Transformer Windings Schemes in Multiple-Output Flyback Auxiliary Power Supplies with High-Input Voltage

Meng, Xianzeng,Li, Chunyan,Meng, Tao,An, Yanhua The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5

In this paper, aiming at high-voltage applications, transformer windings schemes of multiple-output two-transistor flyback converters are investigated, which are mainly based on the stray capacitances effect. First, based on a transformer model including equivalent stray capacitors, the operational principle of the converter is presented, and the main influence of its stay capacitors is determined. Second, the windings structures of the transformer are analyzed and designed based on the stray capacitances effect. Third, the windings arrangements of the transformer are analyzed and designed through a coupling analysis of the secondary windings and a stray capacitance analysis between the primary and secondary windings. Finally, the analysis and design conclusions are verified by experimental results obtained from a 60W laboratory prototype of a multiple-output two-transistor flyback converter.

LabVIEW Based Ventilator Algorithm Design

Chunyan Meng 보안공학연구지원센터 2013 International Journal of Hybrid Information Techno Vol.6 No.3

Analysis and Design of Transformer Windings Schemes in Multiple-Output Flyback Auxiliary Power Supplies with High-Input Voltage

Xianzeng Meng,Chunyan Li,Tao Meng,Yanhua An 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.5

In this paper, aiming at high-voltage applications, transformer windings schemes of multiple-output two-transistor flyback converters are investigated, which are mainly based on the stray capacitances effect. First, based on a transformer model including equivalent stray capacitors, the operational principle of the converter is presented, and the main influence of its stay capacitors is determined. Second, the windings structures of the transformer are analyzed and designed based on the stray capacitances effect. Third, the windings arrangements of the transformer are analyzed and designed through a coupling analysis of the secondary windings and a stray capacitance analysis between the primary and secondary windings. Finally, the analysis and design conclusions are verified by experimental results obtained from a 60W laboratory prototype of a multiple-output two-transistor flyback converter.

Investigation and Implementation of a Passive Snubber with a Coupled-Inductor in a Single-Stage Full-Bridge Boost PFC Converter

Meng, Tao,Ben, Hongqi,Li, Chunyan,Wei, Guo The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.2

In this paper, an improved passive snubber is investigated in a single-phase single-stage full-bridge boost power factor correction (PFC) converter, by which the voltage spike across primary side of the power transformer can be suppressed and the absorbed energy can be transferred to the output side. When compared with the basic passive snubber, the two single-inductors are replaced by a coupled-inductor in the improved snubber. As a result, synchronous resonances in the snubber can be achieved, which can avoid the unbalance of the voltage and current in the snubber. The operational principle of the improved passive snubber is analyzed in detail based on a single-phase PFC converter, and the design considerations of both the snubber and the coupled-inductor are given. Finally, a laboratory-made prototype is built, and the experimental results verify the feasibility of the proposed method and the validity of the theoretical analysis and design method.

Investigation and Implementation of a Passive Snubber with a Coupled-Inductor in a Single-Stage Full-Bridge Boost PFC Converter

Tao Meng,Hongqi Ben,Chunyan Li,Guo Wei 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.2

In this paper, an improved passive snubber is investigated in a single-phase single-stage full-bridge boost power factor correction(PFC) converter, by which the voltage spike across primary side of the power transformer can be suppressed and the absorbed energy can be transferred to the output side. When compared with the basic passive snubber, the two single-inductors are replaced by a coupled-inductor in the improved snubber. As a result, synchronous resonances in the snubber can be achieved, which can avoid the unbalance of the voltage and current in the snubber. The operational principle of the improved passive snubber is analyzed in detail based on a single-phase PFC converter, and the design considerations of both the snubber and the coupled-inductor are given. Finally, a laboratory-made prototype is built, and the experimental results verify the feasibility of the proposed method and the validity of the theoretical analysis and design method.

Research on Support Vector Machine in Image Denoising

Xinfeng Guo,Chunyan Meng 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.2

In this paper, a denoising algorithm and simulation experiments of algorithm based on wavelet transform and support vector machine (SVM) image is proposed, a new method is adopted in the selection of characteristic vector of support vector machine, based on training of support vector machine, the support vector machine model is used to distinguish between noise and the original image, to achieve the effect of denoising. The experimental results show that the method can well remove the noise, and can save some important details of images, compared with other denoising method based on wavelet transform, it has a good advantage.

Multifunctional, flexible and mechanically resilient porous polyurea/graphene composite film

Xu Cui,Chunyan Zhang,Sherif Araby,Rui Cai,Gulnur Kalimuldina,Zhaokun Yang,Qingshi Meng 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.105 No.-

In this study, a porous polyurea/graphene platelet (GnP) composite film with high flexibility and multifunctionalitywas developed and investigated for strain sensing and energy storage applications. Morphology and mechanical properties were studied; tensile strength and Young’s modulus wereenhanced by 132% and 900%, respectively at 5 wt% GnPs. The polyurea/GnP film exhibited high sensitivityto various strains– namely, tension, compression, bending and twisting. In tensile strain, gauge factor was1.86 and 6.26 within strain ranges of 0–30% and 30–60%, respectively. Interestingly, the film showedpiezoresistive and capacitive-type strain sensor under compression load; a 33% increase in relative resistancewith response time of 108 millisecond; and 22% increase in relative capacitance with response timeof 92 millisecond when load of 5 kPa was applied. Furthermore, the strain sensor showed high durabilityand reliability over 20,000 cycles. The developed polyurea/GnP film showed a stable capacitive performanceover 20,000 charge–discharge cycles. This work provides important insights for the potential ofpolyurea/graphene films in multifunctional sensors and flexible energy storage applications.

A magnetostrictive self-powered biosensor based on Au-BaTiO3-FeGa & PDMS

Qiang Zhang,Meng Xu,Yan Liu,Chunyan Zhang,Rui Zhang,Zhiyuan Fu,Jianlong Ji,Riguang Zhang,Shengbo Sang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.117 No.-

Piezoelectric flexible sensors have been used to detect biomolecules such as sweat and glucose because oftheir passive, simple structure and high sensitivity. This paper proposes a novel flexible piezoelectric Au-BaTiO3-FeGa & PDMS biosensor in which magnetostrictive deformation amplifies the surface stress generatedby biomolecules combining on the thin film. The modification process of bovine serum albumin(BSA) binding with the sensor was initially determined by the first principles approach. Then, the sensingmechanism was verified by finite-element simulation. Based on the simulation results, flexible Au-BaTiO3-FeGa & PDMS biosensors were prepared, modified, and measured. The structure, modification,and detection of the sensors were analyzed by digital microscopy, Fourier transform infrared spectrometry(FTIR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The responses ofthe biosensors detecting different BSA solution concentrations under magnetic fields were then investigated. Experimental results indicate that the biosensor has the highest sensitivity under a magnetic fieldof 30 mT.

Analysis of Altered Baseline Brain Activity in Drug-Naive Adult Patients with Social Anxiety Disorder Using Resting-State Functional MRI

Changjian Qiu,Yuan Feng,Yajing Meng,Wei Liao,Xiaoqi Huang,Su Lui,Chunyan Zhu,Huafu Chen,Qiyong Gong,Wei Zhang 대한신경정신의학회 2015 PSYCHIATRY INVESTIGATION Vol.12 No.3

ObjectiveaaWe hypothesize that the amplitude of low-frequency fluctuations (ALFF) is involved in the altered regional baseline brain function in social anxiety disorder (SAD). The aim of the study was to analyze the altered baseline brain activity in drug-naive adult patients with SAD. MethodsaaWe investigated spontaneous and baseline brain activities by obtaining the resting-state functional magnetic resonance imaging data of 20 drug-naïve adult SAD patients and 19 healthy controls. Voxels were used to analyze the ALFF values using one- and two-sample t-tests. A post-hoc correlation of clinical symptoms was also performed. ResultsaaOur findings show decreased ALFF in the bilateral insula, left medial superior frontal gyrus, left precuneus, left middle temporal gyrus, right middle temporal pole, and left fusiform gyrus of the SAD group. The SAD patients exhibited significantly increased ALFF in the right inferior temporal gyrus, right middle temporal gyrus, bilateral middle occipital gyrus, orbital superior frontal gyrus, right fusiform gyrus, right medial superior frontal gyrus, and left parahippocampal gyrus. Moreover, the Liebowitz Social Anxiety Scale results for the SAD patients were positively correlated with the mean Z values of the right middle occipital and right inferior occipital but showed a negative correlation with the mean Z values of the right superior temporal gyrus and right medial superior frontal gyrus. ConclusionaaThese results of the altered regional baseline brain function in SAD suggest that the regions with abnormal spontaneous activities are involved in the underlying pathophysiology of SAD patients.

Draft Genome Assembly and Annotation for Cutaneotrichosporon dermatis NICC30027, an Oleaginous Yeast Capable of Simultaneous Glucose and Xylose Assimilation

Wang Laiyou,Guo Shuxian,Zeng Bo,Wang Shanshan,Chen Yan,Cheng Shuang,Liu Bingbing,Wang Chunyan,Wang Yu,Meng Qingshan 한국균학회 2022 Mycobiology Vol.50 No.1

The identification of oleaginous yeast species capable of simultaneously utilizing xylose and glucose as substrates to generate value-added biological products is an area of key eco- nomic interest. We have previously demonstrated that the Cutaneotrichosporon dermatis NICC30027 yeast strain is capable of simultaneously assimilating both xylose and glucose, resulting in considerable lipid accumulation. However, as no high-quality genome sequenc- ing data or associated annotations for this strain are available at present, it remains chal- lenging to study the metabolic mechanisms underlying this phenotype. Herein, we report a 39,305,439 bp draft genome assembly for C. dermatis NICC30027 comprised of 37 scaffolds, with 60.15% GC content. Within this genome, we identified 524 tRNAs, 142 sRNAs, 53 miRNAs, 28 snRNAs, and eight rRNA clusters. Moreover, repeat sequences totaling 1,032,129 bp in length were identified (2.63% of the genome), as were 14,238 unigenes that were 1,789.35 bp in length on average (64.82% of the genome). The NCBI non-redundant protein sequences (NR) database was employed to successfully annotate 11,795 of these unigenes, while 3,621 and 11,902 were annotated with the Swiss-Prot and TrEMBL databases, respectively. Unigenes were additionally subjected to pathway enrichment analyses using the Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Cluster of Orthologous Groups of proteins (COG), Clusters of orthologous groups for eukaryotic com- plete genomes (KOG), and Non-supervised Orthologous Groups (eggNOG) databases. Together, these results provide a foundation for future studies aimed at clarifying the mech- anistic basis for the ability of C. dermatis NICC30027 to simultaneously utilize glucose and xylose to synthesize lipids.