Analysis of Pre-compensator for Disturbance Signal Elimination in Single-Phase Inverters with Virtual Vector Control

Yuxiang Wang,Yunjie Gu,Wuhua Li,Xiangning He 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In virtual vector control schemes for singlephase current-regulated voltage source inverters, a transient disturbance may be induced due to the time-delay in the virtual orthogonal signal. This disturbance deteriorates the dynamic current-tracking capability and power quality. A unified scalar model is developed to analyze the phenomenon. Based on this model, an improved control scheme with a pre-compensator is proposed to solve the problem. The pre-compensator reshapes the current commands so that the transient disturbance signal is eliminated while the desired response is unaffected. Experimental results of the proposed strategy are compared with the conventional solution to substantiate enhanced dynamic performance.

Research on Tripping Phenomenon and Propagation Characteristic of Wild Trifolium in Xinjiang

Yuxiang Wang,Bo Zhang 한국초지조사료학회 2016 한국초지조사료학회 학술대회논문집 Vol.2016 No.08

Tobacco Sales Bill Recognition Based on Multi-Branch Residual Network

Yuxiang Shan,Cheng Wang,Qin Ren,Xiuhui Wang 한국정보처리학회 2022 Journal of information processing systems Vol.18 No.3

Tobacco sales enterprises often need to summarize and verify the daily sales bills, which may consume substantialmanpower, and manual verification is prone to occasional errors. The use of artificial intelligencetechnology to realize the automatic identification and verification of such bills offers important practicalsignificance. This study presents a novel multi-branch residual network for tobacco sales bills to improve theefficiency and accuracy of tobacco sales. First, geometric correction and edge alignment were performed onthe input sales bill image. Second, the multi-branch residual network recognition model is established andtrained using the preprocessed data. The comparative experimental results demonstrated that the correctrecognition rate of the proposed method reached 98.84% on the China Tobacco Bill Image dataset, which issuperior to that of most existing recognition methods.

Tobacco Retail License Recognition Based on Dual Attention Mechanism

Yuxiang Shan,Qin Ren,Cheng Wang,Xiuhui Wang 한국정보처리학회 2022 Journal of information processing systems Vol.18 No.4

Images of tobacco retail licenses have complex unstructured characteristics, which is an urgent technicalproblem in the robot process automation of tobacco marketing. In this paper, a novel recognition approachusing a double attention mechanism is presented to realize the automatic recognition and information extractionfrom such images. First, we utilized a DenseNet network to extract the license information from the inputtobacco retail license data. Second, bi-directional long short-term memory was used for coding and decodingusing a continuous decoder integrating dual attention to realize the recognition and information extraction oftobacco retail license images without segmentation. Finally, several performance experiments were conductedusing a largescale dataset of tobacco retail licenses. The experimental results show that the proposed approachachieves a correction accuracy of 98.36% on the ZY-LQ dataset, outperforming most existing methods.

Synchronous Frequency Resonance of Virtual Synchronous Generators and Damping Control

Jinhua Wang,Yuxiang Wang,Yunjie Gu,Wuhua Li,Xiangning He 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

The Virtual Synchronous Generator (VSG) is an effective solution for high-penetration renewable energy sources integrated into the power system. Although the VSG has a similar behavior as the conventional synchronous generator, the fast and flexible control capability of converters may give rise to some specific characteristics. In this paper, it is explained that flux dynamics may induce synchronous frequency resonance in VSGs, which possibly leads to power-angle oscillations. A precise small-signal model is established to investigate the synchronous frequency resonance phenomenon. Based on this model, two damping control methods are proposed, which suppress the resonance through increasing the virtual mechanical inertia or adding virtual electrical resistance. The effectiveness of the theoretical conclusions is verified by simulation and experimental results.

Microsatellite Markers Linked to Quantitative Trait Loci Affecting Fatness in Divergently Selected Chicken Lines for Abdominal Fat

Zhang, Hui,Wang, Shouzhi,Li, Hui,Yu, Xijiang,Li, Ning,Zhang, Qin,Liu, Xiaofeng,Wang, Qigui,Hu, Xiaoxiang,Wang, Yuxiang,Tang, Zhiquan Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.10

Abdominal fat characters are complex and economically important in the poultry industry. Their selection may benefit from the implementation of marker-assisted selection (MAS). The objective of this study was to identify the markers linked to QTL responsible for fatness traits. The Northeast Agricultural University broiler lines divergently selected for abdominal fat content (NEAUHLF) were used in the study. A total of 596 individuals from the divergent tails from the 6th to the 10th generations were genotyped at 23 microsatellite markers on chromosome 1. The differences of allele frequencies of all marker alleles between the divergent tails across the five generations were recorded. The allele frequencies of five markers, including LEI0209, LEI0146, MCW0036, ADL328 and MCW0115, had significant differences between the two tails in all five generations. The resulting p-values using Fisher's exact test on eleven markers, containing MCW248, MCW0010, MCW0106, LEI0252, LEI0068, MCW0018, MCW0061, LEI0088, MCW200, MCW283 and ROS0025, had a decreasing tendency from the 6th to the 10th generation. Statistical analysis showed that polymorphisms of the eight markers, including LEI0209, LEI0146, ROS0025, MCW0115, MCW0010, MCW0036, MCW283, ADL328, were significantly (p<0.0011) or suggestively (p<0.05) associated with abdominal fat content (AFW and AFP) across generations. It is concluded that the eight markers could be associated with the QTL affecting the deposition of abdominal fat in broiler chickens.

Factors controlling the geochemical differences between two types of rhyolites in the middle Okinawa Trough

Yuxiang Zhang,Zhigang Zeng,Xiaoyuan Wang,Shuai Chen,Xuebo Yin 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.1

The origin of the felsic volcanic rocks in the Okinawa Trough (OT) remains uncertain. In the middle Okinawa Trough (MOT), two types of rhyolites (type 1 and type 2 rhyolites) have been recognized. Research on the diverse volcanic rocks should be prioritized to determine the magmatic origins of these rocks. Consequently, in this article, the geochemical differences and controlling factors for these two types of MOT rhyolites are systematically discussed. Type 2 rhyolites have higher Dy/Yb and Nb/Ta ratios than type 1 rhyolites, implying that the former might be influenced by a greater contribution of amphibole. Quantitative models suggest that type 1 rhyolites could have formed via the remelting of andesites when amphiboles remain in the source, whereas type 2 rhyolites could have formed without residual amphiboles. These two distinct melting models effectively explain most discrepancies between the major and trace element compositions of type 1 and 2 rhyolites. Additionally, the lower Mg# and δEu values of type 2 rhyolites are partly caused by significant magmatic differentiation. Quasi-linear correlations between some major oxides, trace element ratios and Sr-Nd isotopic ratios for type 2 rhyolites suggest that these rhyolites might have been contaminated by crustal rocks or melts with compositions similar to those of the Kueishantao (KST) andesites or the Middle Miocene upper crustal rocks of SW Japan. Therefore, isotopically enriched crustal materials likely remain in the OT crust.

A dual-experience pool deep reinforcement learning method and its application in fault diagnosis of rolling bearing with unbalanced data

Yuxiang Kang,Guo Chen,Wenping Pan,Xunkai Wei,Hao Wang,Zhiyuan He 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.6

A dual-experience pool deep reinforcement learning (DEPDRL) model is proposed for rolling bearing fault diagnosis with unbalanced data. In this method, a dualexperience pool structure is designed to store the sample data of majority and minority classes. A parallel double residual network model is established to extract deep features of the majority and minority input samples, respectively. In the process of training, the proposed balanced cross-sampling technique is used to randomly select samples from dual-experience pool in a certain proportion to realize the training of a double residual network model. We show the effectiveness of our method on three standard data sets, and compared with Resnet18, DCNN, DQN and DQNimb methods, the results show that DEPDRL has the best performance. Finally, with wavelet time-frequency graph as input, DEPDRL is applied to rolling bearing fault diagnosis with unbalanced test data. The results show that on a variety of unbalanced data sets, both the diagnostic accuracy and the G-means value of the DEPDRL are more than 5 % higher than other algorithms, which fully indicates that the DEPDRL has a very high fault diagnosis ability of rolling bearing with unbalanced data.

Influence of backbone modification of difluoroquinoxaline-based copolymers on the interchain packing, blend morphology and photovoltaic properties of nonfullerene organic solar cells

Li, Yuxiang,Kim, Minseok,Wu, Ziang,Lee, Changyeon,Lee, Young Woong,Lee, Jin-Woo,Lee, Young Jun,Wang, Ergang,Kim, Bumjoon J.,Woo, Han Young The Royal Society of Chemistry 2019 Journal of Materials Chemistry C Vol.7 No.6

<P>In order to understand the influence of molecular ordering and orientation on the performance of nonfullerene (NF) solar cells, we synthesized a series of difluoroquinoxaline-based alternating copolymers: starting from poly(2,2′-bithiophene-<I>alt</I>-(2,3-bis(3,4-bis(octyloxy)phenyl)-6,7-difluoroquinoxaline)) (PDFQx-2T), we modified the polymeric backbone by incorporating fluorine atoms (PDFQx-2T2F) or thiophene (PDFQx-3T) or a benzene ring (PDFQx-2TB) in the bithiophene comonomeric unit. The structure modification significantly affected the photovoltaic performance with power conversion efficiencies (PCEs) of 3.95% for PDFQx-2TB:ITIC, 4.82% for PDFQx-2T:ITIC, 4.93% for PDFQx-2T2F:ITIC and 8.13% for PDFQx-3T:ITIC. The dramatic increase in the PCE of PDFQx-3T:ITIC was attributed to improvements in the short-circuit current density (<I>J</I>SC) and fill factor (FF). From the resonant soft X-ray scattering and grazing incidence X-ray scattering measurements, the PDFQx-3T polymers had well-developed, face-on oriented crystallites, allowing the formation of face-to-face alignment with the face-on ordered ITIC molecules at the interfaces. Also, the PDFQx-3T:ITIC blend films exhibited well intermixed blend morphology with smaller domain spacings. These combined features contributed to efficient charge generation with the highest exciton dissociation probability among the four different polymer:ITIC systems. In addition, dominant face-on orientation of both PDFQx-3T polymers and ITIC acceptors with a balanced crystalline coherence length ratio (CCLpolymer/CCLITIC) (0.87, based on the out-of-plane (010) diffraction peaks of PDFQx polymers and ITIC acceptors) led to a more balanced charge mobility than other blends, explaining the highest <I>J</I>SC and FF in the PDFQx-3T:ITIC NF devices.</P>

Recent advances in carbon quantum dots for virus detection, as well as inhibition and treatment of viral infection

Xue Yuxiang,Liu Chenchen,Andrews Gavin,Wang Jinyan,Ge Yi 나노기술연구협의회 2022 Nano Convergence Vol.9 No.15

In the last decade, carbon quantum dots (CQDs), as a novel class of carbon-based nanomaterials, have received increasing attention due to their distinct properties. CQDs are ultimately small nanoparticles with an average size below 10 nm, possessing high water solubility, alluring photoluminescence, photostability, excellent biocompatibility, low/none toxicity, environmental friendliness, and high sustainability, etc. In history, there are intermittent threats from viruses to humans, animals and plants worldwide, resulting in enormous crises and impacts on our life, environment, economy and society. Some recent studies have unveiled that certain types of CQDs exhibited high and potent antiviral activities against various viruses such as human coronavirus, arterivirus, norovirus and herpesvirus. Moreover, they have been successfully explored and developed for different virus detections including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This article exclusively overviews and discusses the recent progress of designing, synthesizing, modifying/functionalizing and developing CQDs towards effective virus detection as well as the inhibition and treatment of viral infection. Their mechanisms and applications against various pathogenic viruses are addressed. The latest outcomes for combating the coronavirus disease 2019 (COVID-19) utilizing CQDs are also highlighted. It can be envisaged that CQDs could further benefit the development of virus detectors and antiviral agents with added broad-spectrum activity and cost-effective production.