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Virtual Signal Injected MTPA Control for DTC Five-Phase IPMSM Drives
Liu, Guohai,Yang, Yuqi,Chen, Qian The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4
This paper introduces a virtual signal injected maximum torque per ampere (MTPA) control strategy for direct-torque-controlled five-phase interior permanent magnet synchronous motor (IPMSM) drives. The key of the proposed method is that a high frequency signal is injected virtually into the stator flux linkage. Then the responding stator current is calculated and regulated to compensate the amplitude of the flux linkage. This is done according to the relationship between the stator current and the stator flux linkage. Since the proposed method does not inject any real signals into the motor, it does not cause any of the problems associated with high-frequency signals, such as additional copper loss and extra torque ripple. Simulation and experimental results are offered to verify the effectiveness of the proposed method.
Virtual Signal Injected MTPA Control for DTC Five-Phase IPMSM Drives
Guohai Liu,Yuqi Yang,Qian Chen 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4
This paper introduces a virtual signal injected maximum torque per ampere (MTPA) control strategy for direct-torquecontrolledfive-phase interior permanent magnet synchronous motor (IPMSM) drives. The key of the proposed method is that ahigh frequency signal is injected virtually into the stator flux linkage. Then the responding stator current is calculated andregulated to compensate the amplitude of the flux linkage. This is done according to the relationship between the stator currentand the stator flux linkage. Since the proposed method does not inject any real signals into the motor, it does not cause any of theproblems associated with high-frequency signals, such as additional copper loss and extra torque ripple. Simulation andexperimental results are offered to verify the effectiveness of the proposed method.
Higher-Order Conditional Random Field established with CNNs for Video Object Segmentation
( Chuanyan Hao ),( Yuqi Wang ),( Bo Jiang ),( Sijiang Liu ),( Zhi-xin Yang ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.9
We perform the task of video object segmentation by incorporating a conditional random field (CRF) and convolutional neural networks (CNNs). Most methods employ a CRF to refine a coarse output from fully convolutional networks. Others treat the inference process of the CRF as a recurrent neural network and then combine CNNs and the CRF into an end-to-end model for video object segmentation. In contrast to these methods, we propose a novel higher-order CRF model to solve the problem of video object segmentation. Specifically, we use CNNs to establish a higher-order dependence among pixels, and this dependence can provide critical global information for a segmentation model to enhance the global consistency of segmentation. In general, the optimization of the higher-order energy is extremely difficult. To make the problem tractable, we decompose the higher-order energy into two parts by utilizing auxiliary variables and then solve it by using an iterative process. We conduct quantitative and qualitative analyses on multiple datasets, and the proposed method achieves competitive results.
Boran Hao,Yuqi Liu,Xinye Yu,Kan Zhang 한국고분자학회 2021 Macromolecular Research Vol.29 No.1
A benzoxazine monomer with ortho-maleimide functionality has been synthesized using ortho-maleimide functional phenol, aniline and paraformaldehyde as starting materials. The chemical structure of this benzoxazine monomer is verified by 1H and 13C nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectroscopies, elemental analysis as well as high-resolution mass spectrometry. The polymerization behavior of benzoxazine has been studied by differential scanning calorimetry (DSC) and in situ FT-IR. Besides, the kinetic parameters have been calculated by non-isothermal DSC with different heating rates. The apparent activation energy value of the ortho-maleimide functional benzoxazine is calculated to be 72.43 kJ/mol based on the Starink method. In addition, our predicted thermograms based on the developed model fit well with the curves obtained from experimental DSC results. Moreover, DSC and thermogravimetric analyses (TGA) are used to determine the thermal properties of the cross-linked thermoset. The resulting polybenzoxazine derived from ortho-maleimide functional shows excellent thermal stability (T g of 247 oC; T d5 of 333 oC), evidencing its great potential application in high-performance fields.
Lan Kang,Yuqi Wang,Xinpei Liu,Brian Uy 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.4
In order to obtain high bearing capacity and good ductility simultaneously, a structural column with hybrid normal and high strength steel (HNHSS) welded box section has been developed. Residual stress is an important factor that can influence the behaviour of a structural member in steel structures. Accordingly, the magnitudes and distributions of residual stresses in HNHSS welded box sections were investigated experimentally using the sectioning method. In this study, the following four box sections were tested: one normal strength steel (NSS) section, one high strength steel (HSS) section, and two HNHSS sections. Based on the experimental data from previous studies and the test results of this study, the effects of the width-to-thickness ratio of plate, yield strength of plate, and the plate thickness of the residual stresses of welded box sections were investigated in detail. A unified residual stress model for NSS, HSS and HNHSS welded box sections was proposed, and the corresponding simplified prediction equations for the maximum tensile residual stress ratio (<i>σ</i><sub>rt</sub>/<i>f</i><sub>y</sub>) and average compressive residual stress ratio (<i>σ</i><sub>rc</sub>/<i>f</i><sub>y</sub>) in the model were quantitatively established. The predicted magnitudes and distributions of residual stresses for four tested sections in this study by using the proposed residual stress model were compared with the experimental results, and the feasibility of this proposed model was shown to be in good agreement.
LICONG WANG,YUAN LIU,YUSHAN ZHANG,DAN CHEN,YUQI WANG,ZELIANG DONG,YONGCHAO LU,XIPING HUANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.7
Magnesium borate (Mg 2 B 2 O 5 Þ nanorods were synthesized by a two-step process, includingsolution-chemical technology and a ternary-°ux method, using concentrated seawater and H 3 BO 3as raw materials. X-ray di®raction (XRD) showed that the sample had triclinic structure. Scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HR-TEM) indicated that it consisted of rod-like particles with an average diameter of 100 – 150 nmand length over 5 ? m. Di®erential thermal analysis (DTA) con¯rmed that the melting point ofthe ternary-°ux and the formation temperature of Mg 2 B 2 O 5 were lower than single-°ux process. The formation of Mg 2 B 2 O 5 nanorods was more e±cient by ternary-°ux than single-°ux. Me-chanical property of Mg 2 B 2 O 5 nanorods reinforced Nylon-6 composites showed that KH550 wasthe optimal coupling agent and made the strength of the composites to be improved to differentdegrees.
Jianfeng Gou,Qiuling Ma,Yuqi Cui,Xiaoyong Deng,Huixuan Zhang,Xiuwen Cheng,Xiaoli Li,Mingzheng Xie,Qingfeng Cheng,Huiling Liu 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.49 No.-
In this study, high visible light response and charge separation efficiency of body-centered cubic Ag3PO4sub-microcrystals were fabricated through ultrasound-precipitation process. Additionally, the parameterswere optimized by photocatalytic (PC) removal degradation of diclofenac based on response surfacemethodology. Results indicated that the PC removal efficiency of diclofenac was significantly affected byAg3PO4 content and pH value. Under the optimized conditions, 99.9% of diclofenac could be degradedwithin 16 min Xenon illumination. Furthermore, three PC removal degradation pathways of diclofenacwere proposed, including OH-adduct to aromatic ring, direct oxidation by photoinduced holes anddecarboxylation of side chain from the parent compound.
Production of Tween 80-inducing Esterase by Acinetobacter sp. B1 Using Response Surface Methodology
Ma, Peiyu,Li, Yuqi,Miao, Chensi,Sun, Yunpeng,Liu, Chunhui,Li, Huijuan The Korean Society for Microbiology and Biotechnol 2019 한국미생물·생명공학회지 Vol.47 No.1
Esterase produced by Acinetobacter sp. B1 (strain B1) was optimized by means of one-variable-at-a-time and response surface methodologies. Results of the one-variable-at-a-time experiment showed that Tween 80 significantly increased esterase production of strain B1. The addition of Tween 80 to the culture medium increased the biomass and esterase activity of strain B1, stimulated content of total extracellular protein, and enhanced the oleic acid (C18:1) composition in the cell membrane of strain B1. The influence of eight culture variables on esterase production was evaluated by Plackett-Burman design. Results showed that Tween 80, pH, and $K_2HPO_4$ significantly affected the esterase production of strain B1. Tween 80, pH, and $K_2HPO_4$ were further optimized by central composite design. Under the optimized conditions (w/v, soluble starch 2.5%, tryptone 1.5%, Tween 80 0.8%, $K_2HPO_4$ 0.5%, NaCl 0.5%, pH 8.0, inoculum size 1%, and inoculum age 24 h), the maximum esterase activity of strain B1 was 152.13 U/ml, which was 10-fold higher than that of non-optimization after 36 h cultivation.
Functional Roles of Exosomes in Allergic Contact Dermatitis
Song Bocui,Chen Qian,Li Yuqi,Zhan Shuang,Zhao Rui,Shen Xue,Liu Min,Tong Chunyu 한국미생물·생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.12
Allergic contact dermatitis (ACD) is an allergen-specific T-cell-mediated inflammatory response, albeit with unclear pathogenesis. Exosomes are nanoscale extracellular vesicles secreted by several cell types and widely distributed in various biological fluids. Exosomes affect the occurrence and development of ACD through immunoregulation among other ways. Nevertheless, the role of exosomes in ACD warrants further clarification. This review examines the progress of research into exosomes and their involvement in the pathogenesis, diagnosis, and treatment of ACD and provides ideas for exploring new diagnostic and treatment methods for this disease.