Research on High-Frequency Isolation Type of Dual-PWM Variable Frequency Speed Regulation

Liu Jiangong,Liu Wenzhuang,Wang Yiying,Zhang Guilin,Chen Longfei 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4

Frequency converters are widely used in power grids, motor speed regulation, and other fields. When the voltage level is above low voltage and the workspace is limited, traditional frequency converters mostly adopt the power frequency transformer to connect to the power grid. But the structure has the problems of bigger volume and complexity. To solve these problems, this paper proposes a three-stage topology structure of high-frequency isolation type of dual-PWM variable frequency speed regulation based on three-phase rectification, single active isolated DC/DC converter, and three-phase inverter, and analyzes its power transmission characteristics in detail. And a new method that combines high-frequency electrical isolation and frequency conversion is discussed. Then, the control strategies of the new method are also described. Lastly, simulation and experiment are constructed to verify the new design method is correct and feasible, and that the steady and dynamic characteristics of the three-stage high-frequency isolated frequency converter are better.

Main Content Extraction from Web Pages Based on Node Characteristics

Liu, Qingtang,Shao, Mingbo,Wu, Linjing,Zhao, Gang,Fan, Guilin,Li, Jun Korean Institute of Information Scientists and Eng 2017 Journal of Computing Science and Engineering Vol.11 No.2

Main content extraction of web pages is widely used in search engines, web content aggregation and mobile Internet browsing. However, a mass of irrelevant information such as advertisement, irrelevant navigation and trash information is included in web pages. Such irrelevant information reduces the efficiency of web content processing in content-based applications. The purpose of this paper is to propose an automatic main content extraction method of web pages. In this method, we use two indicators to describe characteristics of web pages: text density and hyperlink density. According to continuous distribution of similar content on a page, we use an estimation algorithm to judge if a node is a content node or a noisy node based on characteristics of the node and neighboring nodes. This algorithm enables us to filter advertisement nodes and irrelevant navigation. Experimental results on 10 news websites revealed that our algorithm could achieve a 96.34% average acceptable rate.

Phenyl VOCs catalytic combustion on supported CoMn/AC oxide catalyst

Guilin Zhou,Xiaoling He,Sheng Liu,Hongmei Xie,Min Fu 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

Supported CoMn/AC composite oxide catalysts were prepared by a typical impregnation methodat different calcination temperatures. The prepared CoMn/AC catalysts were characterized, and thecatalytic activity of the prepared supported CoMn/AC oxide catalysts was also investigated by thecatalytic combustion of phenyl volatile organic compounds (VOCs) (benzene, toluene, andethylbenzene). XRD and XPS results indicated that MnCo2O4 and CoMn2O4 were the main crystalphase species in the prepared supported CoMn/AC oxide catalysts. The active components wereobserved to be highly dispersed and had small crystal sizes. The toluene catalytic combustion resultsdemonstrated that the CAT350 catalyst had higher toluene catalytic combustion activity than theCTA250, CAT300, and CAT400 catalysts. The toluene catalytic combustion conversion of the CAT350catalyst exceeded 93.5% at 235 8C, with a decreased toluene concentration in air of less than 130 ppm at250 8C. The order of toluene catalytic activity of the supported CoMn/AC oxide catalystswas as follows:CAT250 < CAT300 CAT400 < CAT350. The catalytic combustion activity and stability of the CAT350catalyst also increased with the increase in reaction temperature. The catalytic activity of the CAT350catalyst was investigated to bring about the complete oxidation of benzene, ethylbenzene, and toluene. The combustibility of phenyl VOCs on the CAT350 catalyst was observed to follow the orderbenzene < ethylbenzene < toluene. Therefore, the differences in the phenyl VOC catalytic combustionperformances of the supported CoMn/AC composite oxide catalysts can be attributed to the differentphysical chemistry properties of the phenyl VOC molecules and the catalyst.

Main Content Extraction from Web Pages Based on Node Characteristics

Qingtang Liu,Mingbo Shao,Linjing Wu,Gang Zhao,Guilin Fan,Jun Li 한국정보과학회 2017 Journal of Computing Science and Engineering Vol.11 No.2

Main content extraction of web pages is widely used in search engines, web content aggregation and mobile Internet browsing. However, a mass of irrelevant information such as advertisement, irrelevant navigation and trash information is included in web pages. Such irrelevant information reduces the efficiency of web content processing in content-based applications. The purpose of this paper is to propose an automatic main content extraction method of web pages. In this method, we use two indicators to describe characteristics of web pages: text density and hyperlink density. According to continuous distribution of similar content on a page, we use an estimation algorithm to judge if a node is a content node or a noisy node based on characteristics of the node and neighboring nodes. This algorithm enables us to filter advertisement nodes and irrelevant navigation. Experimental results on 10 news websites revealed that our algorithm could achieve a 96.34% average acceptable rate.

Adopting Text Mining on Rehabilitation Therapy Repositioning for Stroke

Meng, Guilin,Huang, Yong,Yu, Qi,Ding, Ying,Wild, David,Zhao, Yanxin,Liu, Xueyuan,Song, Min Frontiers Media S.A. 2019 Frontiers in neuroinformatics Vol.13 No.-

<P>Stroke is a common disabling disease that severely affects the daily life of patients. Accumulating evidence indicates that rehabilitation therapy can improve movement function. However, no clear guidelines have specific and effective rehabilitation therapy schemes, and the development of new rehabilitation techniques has been relatively slow. This study used a text mining approach, the ABC model, to identify an existing rehabilitation candidate therapy method that is most likely to be repositioned for stroke. In the model, we built the internal links of stroke (A), assessment scales (B), and rehabilitation therapies (C) in PubMed and the links were related to upper limb function measurements for patients with stroke. In the first step, using E-utility, we retrieved both stroke-related assessment scales and rehabilitation therapy records and then compiled two datasets, which were called Stroke_Scales and Stroke_Therapies, respectively. In the next step, we crawled all rehabilitation therapies co-occurring with the Stroke_Therapies and then named them as All_Therapies. Therapies that were already included in Stroke_Therapies were deleted from All_Therapies; therefore, the remaining therapies were the potential rehabilitation therapies, which could be repositioned for stroke after subsequent filtration by a manual check. We identified the top-ranked repositioning rehabilitation therapy and subsequently examined its clinical validation. Hand-arm bimanual intensive training (HABIT) was ranked the first in our repositioning rehabilitation therapies and had the most interaction links with Stroke_Scales. HABIT significantly improved clinical scores on assessment scales [Fugl-Meyer Assessment (FMA) and action research arm test (ARAT)] in the clinical validation study for acute stroke patients with upper limb dysfunction. Therefore, based on the ABC model and clinical validation, HABIT is a promising repositioned rehabilitation therapy for stroke, and the ABC model is an effective text mining approach for rehabilitation therapy repositioning. The findings in this study would be helpful in clinical knowledge discovery.</P>

Pattern Recognition of Partial Discharge in Power Transformer Based on InfoGAN and CNN

Lv Fangcheng,Liu Guilin,Wang Qiang,Lu Xiuquan,Lei Shengfeng,Wang Shenghui,Ma Kang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

As an important equipment in the power system, it has a significant meaning in scientifically diagnosing the insulation state of oil-immersed power transformers. At present, the pattern recognition of partial discharge (PD) in a transformer has the problem of the insufficient generalization ability of the classifier due to scarcity and imbalance of samples, resulting in low recognition accuracy. To solve this problem, this paper proposes a pattern recognition of the PD method based on information maximizing generative adversarial nets (InfoGAN) and convolutional neural networks. In this method, phase-resolved partial discharge (PRPD) maps, constructed from pulse current waveforms, are chosen as the training samples. First, the InfoGAN is trained to generate new samples which expanded the original sample database, then various classifiers are trained by using the expanded sample database to realize the pattern recognition. Results of the test show that the proposed method can generate new highly similar samples more stable than other data enhancement methods, and effectively enrich the data diversity. In addition, the classifier trained by the expanded sample database has better generalization ability and is applicable to different classifiers, while residual network 18 has the highest recognition rate of 99.0%. This method can effectively balance and expand PRPD samples, and improve the recognition accuracy of the classifier to a certain extent. It has a good application prospect in PD diagnosis engineering.

Downregulation of cellular prion protein inhibited the proliferation and invasion and induced apoptosis of Marek’s disease virus-transformed avian T cells

Xuerui Wan,Runxia Yang,Guilin Liu,Manling Zhu,Tianliang Zhang,Lei Liu,Run Wu 대한수의학회 2016 Journal of Veterinary Science Vol.17 No.2

Cellular prion protein (PrPC) is ubiquitously expressed in the cytomembrane of a considerable number of eukaryotic cells. Although several studies have investigated the functions of PrPC in cell proliferation, cell apoptosis, and tumorigenesis of mammals, the correlated functions of chicken PrPC (chPrPC) remain unknown. In this study, stable chPrPC-downregulated Marek’s disease (MD) virus-transformed avian T cells (MSB1-SiRNA-3) were established by introducing short interfering RNA (SiRNA) targeting chicken prion protein genes. We found that downregulation of chPrPC inhibits proliferation, invasion, and migration, and induces G1 cell cycle phase arrest and apoptosis of MSB1-SiRNA-3 cells compared with Marek’s disease virus-transformed avian T cells (MSB1) and negative control cells. To the best of our knowledge, the present study provides the first evidence supporting the positive correlation between the expression level of chPrPC and the proliferation, migration, and invasion ability of MSB1 cells, but appears to protect MSB1 cells from apoptosis, which suggests it functions in the formation and development of MD tumors. This evidence may contribute to future research into the specific molecular mechanisms of chPrPC in the formation and development of MD tumors.

Detecting small lung tumors in mouse models by refractive-index microradiology

Chien, Chia-Chi,Zhang, Guilin,Hwu, Y.,Liu, Ping,Yue, Weisheng,Sun, Jianqi,Li, Yan,Xue, Hongjie,Xu, Lisa X.,Wang, Chang Hai,Chen, Nanyow,Lu, Chien Hung,Lee, Ting-Kuo,Yang, Yuh-Cheng,Lu, Yen-Ta,Ching, Y Springer-Verlag 2011 ANALYTICAL AND BIOANALYTICAL CHEMISTRY Vol.401 No.3

A study on tensile strength mechanism of hypoeutectic gray cast iron reinforced by composite silicon carbide powder

Chunfeng Wang,Jun Yang,Guilin Liu,Hong Gao,Meiling Chen 한양대학교 세라믹연구소 2022 Journal of Ceramic Processing Research Vol.23 No.4

This study aims to reveal the changes in the microstructure of hypoeutectic gray cast iron under the addition of compositesilicon carbide powder of different mass fractions, and to explore how modified silicon carbide (SiC) particles of different sizesand contents improve the mechanical properties of hypoeutectic gray cast iron. The results showed that the modified SiCparticles increased the nucleation, the undercooling and microstructure of hypoeutectic gray cast iron, and the tensile strengthof the iron at room temperature was increased by 18,28%. The present work solves the problem that traditional SiC ceramicparticles are prone to agglomeration in molten metal, analyzes its action mechanism, and can expand the application of SiCceramic particles to strengthening metal properties of casting materials.

Application of copper sulfate based fenton-like catalyst in degradation of quinoline

Zhaojie Jiao,Haifeng Gong,Ye Peng,Guilin Zhou,Xianming Zhang,Xu Gao,Yunqi Liu 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.5

In the practical application of water treatment, the Fenton reaction usually works at a lower pH. To overcome the above shortcomings, a Fenton-like reaction system with copper sulfate as a catalyst was proposed. In this paper, quinoline was used as the target pollutant and the effects of catalyst dosage, H₂O₂ dosage, reaction temperature, and initial concentration of quinoline and pH on the removal effect were investigated, and the evolution in pH and hydroxyl radical concentration during reaction, as well as the possible catalytic mechanism and degradation pathway were clarified. The results show that under a catalyst dosage of 0.4 g・L<SUP>-1</SUP>, a H₂O₂ dosage of 196 mmol・L<SUP>-1</SUP>, a quinoline concentration of 100 mg・L<SUP>-1</SUP> and a temperature of 75°C, the removal of quinoline and total organic carbon (TOC) reaches 99.5% and 87.2% in 65 min, respectively. Furthermore, the copper sulfate-driven homogeneous Fenton system exhibits a superior adaptability to pH in the range of 3.8 to 8.8. In the degradation of quinoline, ·OH radicals may attack the nitrogen ring and the benzene ring in sequence. The work provides a technical support for the treatment of organic wastewater, and shows promising in practical applications.