Phase-Shift Triple Full-Bridge ZVZCS Converter with All Soft Switched Devices

Junjie Zhu,Qinsong Qian,Shengli Lu,Weifeng Sun 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6

This paper proposes a Phase-Shift Triple Full-Bridge (PSTB) Zero-Voltage Zero-Current-Switching (ZVZCS) converter with a high switching frequency and high efficiency. In the proposed converter, all three bridge legs are shared leading-legs, and all three transformers work in the Discontinuous Conduction Mode (DCM). Thus, all of the switches and diodes in the PSTB ZVZCS can be soft switched. Moreover, since all of the transformers can pass energy from the primary-side to the secondary- side when their primary-side currents are not zero, there is no circulating current. As a result, the PSTB ZVZCS converter can achieve a high efficiency at high operating frequencies. A theoretical analysis and the characteristics of the proposed converter are presented and verified on a 1MHz 200~300V/24V 1.2kW hardware prototype. The proposed converter can reach a peak efficiency of 96.6%.

Metallorganic Chemical Vapor Deposition of ZnO Films on Carbonized Si(111) and Si(100) Substrates

Zhu, Junjie,Yao, Ran,Fu, Zhuxi,Lee, In-Hwan The Electrochemical Society 2006 Journal of the Electrochemical Society Vol.153 No.9

Metalorganic Chemical Vapor Deposition of ZnO Films on Si (111) Substrates Using 3C-SiC Buffer Layers

Zhu Junjie,Lee InHwan,Ran Yao,Zhuxi Fu 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.3

Epitaxial ZnO films were prepared on Si (111) substrates using epitaxial 3C-SiC buffer layers. In particular, we tried different epitaxial 3C-SiC buffer layers to grow high quality ZnO films on silicon substrates by metal-organic chemical vapor deposition. The relationship between the quality of ZnO epitaxial layers and that of the SiC buffer layers was investigated. The epitaxial ZnO films were obviously improved by improving the SiC buffer layers. When the quality of the SiC buffer layers was good enough, the effect became less obvious.

Phase-Shift Triple Full-Bridge ZVZCS Converter with All Soft Switched Devices

Zhu, Junjie,Qian, Qinsong,Lu, Shengli,Sun, Weifeng The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6

This paper proposes a Phase-Shift Triple Full-Bridge (PSTB) Zero-Voltage Zero-Current-Switching (ZVZCS) converter with a high switching frequency and high efficiency. In the proposed converter, all three bridge legs are shared leading-legs, and all three transformers work in the Discontinuous Conduction Mode (DCM). Thus, all of the switches and diodes in the PSTB ZVZCS can be soft switched. Moreover, since all of the transformers can pass energy from the primary-side to the secondary-side when their primary-side currents are not zero, there is no circulating current. As a result, the PSTB ZVZCS converter can achieve a high efficiency at high operating frequencies. A theoretical analysis and the characteristics of the proposed converter are presented and verified on a 1MHz 200~300V/24V 1.2kW hardware prototype. The proposed converter can reach a peak efficiency of 96.6%.

Screening of serum exosome markers for colorectal cancer based on Boruta and multi-cluster feature selection algorithms

Zhu Jian,Luo Junjie,Ma Yao 대한독성 유전단백체 학회 2024 Molecular & cellular toxicology Vol.20 No.2

Background Early and timely diagnosis benefits the prognosis of patients with colorectal cancer (CRC). The purpose of this study was to explore biomarkers with diagnostic ability in colorectal cancer. Objective Boruta and multi-cluster feature selection (MCFS) algorithms were employed to analyze the expression data of serum exosome-sourced microRNAs (miRNAs) in CRC patients in the Gene Expression Omnibus (GEO) database to find candidate feature miRNAs that could distinguish between CRC and normal samples. To identify the feature miRNAs with the highest diagnostic ability, different support vector machine (SVM) classifiers were constructed, and the SVM classifier with the highest F1 score was selected based on IFS curve. To validate the clinical application value of the classifier, serum samples from 32 CRC patients and 19 healthy individuals were collected as external validation sets, and serum exosomes were extracted for quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The data were imported into the model to verify the performance of the model. Result After feature selection by Boruta and MCFS algorithms, the first five candidate miRNAs (miR-21, miR-193b, miR-23a, miR-575, and miR-610) with sufficient ability to distinguish sample types were identified. In a series of classifiers constructed, the SVM classifier composed of the first four feature miRNAs (miR-21, miR-193b, miR-23a, and miR-575) was determined to have the best classification effect. qRT-PCR results of serum exosome miRNAs in clinical samples demonstrated that the expression of miR-21, miR-193b, and miR-23a in serum exosomes from CRC patients was significantly higher than that in normal samples, while that of miR-575 was significantly lower than that in normal samples. Subsequently, the receiver operating characteristics (ROC) curve of the diagnostic model based on four feature miRNAs was plotted. According to the results, the area under concentrations curves (AUC) value of the diagnostic model was 0.854, which suggested that the predictive performance of the model built on miR-21, miR-193b, miR-23a, and miR-575 was effective enough to distinguish healthy subjects from CRC patients. In addition, the expression of miR-21, miR-193b, miR-23a, and miR-575 was closely related to the tumor size, stage, and the presence of distant metastasis in CRC patients. Conclusion MiR-21, miR-193b, miR-23a, and miR-575 may be a new potential biomarker combination for the diagnosis of CRC. Clinical biopsy combined with these miRNA biomarkers is expected to promote the early diagnosis of CRC, thus optimizing the prognosis of CRC patients.

Topology Modeling and Vulnerability Analysis of China Mine Power Grid Based on Complex Network Theory

Junji Wang,Caoyuan Ma,Chunxiao Li,Xinshang Zhu,Kang Zhao 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.10

A structural vulnerability analysis of China mine power grid, which considering the particular of topological structure and the increase gas power generation nodes, is proposed based on complex network theory. According to transmission capacity of weighted network model, this paper analyses the network characteristics, including degree distribution, clustering coefficient and average path length, to prove that the mine power grid is a scale -free network. The node importance, node betweenness, edge weight and edge betweenness are regarded as the index of identification and the remaining load capacity after attack is chosen as evaluation index to analyze the structural vulnerability of mine power grid to have a fault simulation of the mine power grid before and after adding gas power generation nodes. The results of fault simulation show that the model is in line with the actual situation of the China mine power grid, and can better identify and assess the vulnerability of the mine power grid.

Glutamate attenuates lipopolysaccharide induced intestinal barrier injury by regulating corticotropin-releasing factor pathway in weaned pigs

Guo Junjie,Liang Tianzeng,Chen Huifu,Li Xiangen,Ren Xiaorui,Wang Xiuying,Xiao Kan,Zhao Jiangchao,Zhu Huiling,Liu Yulan 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.8

Objective: The purpose of this study was to evaluate the protection of glutamate (GLU) against the impairment in intestinal barrier function induced by lipopolysaccharide (LPS) stress in weaned pigs. Methods: Twenty-four weaned pigs were divided into four treatments containing: i) nonchallenged control, ii) LPS-challenged control, iii) LPS+1.0% GLU, and iv) LPS+2.0% GLU. On day 28, pigs were treated with LPS or saline. Blood samples were collected at 0, 2, and 4 h post-injection. After blood samples collection at 4 h, all pigs were slaughtered, and spleen, mesenteric lymph nodes, liver and intestinal samples were obtained. Results: Dietary GLU supplementation inhibited the LPS-induced oxidative stress in pigs, as demonstrated by reduced malondialdehyde level and increased glutathione level in jejunum. Diets supplemented with GLU enhanced villus height, villus height/crypt depth and claudin-1 expression, attenuated intestinal histology and ultrastructure impairment induced by LPS. Moreover, GLU supplementation reversed intestinal intraepithelial lymphocyte number decrease and mast cell number increase induced by LPS stress. GLU reduced serum cortisol concentration at 4 h after LPS stress and downregulated the mRNA expression of intestinal corticotropin-releasing factor signal (corticotrophin-releasing factor [CRF], CRF receptor 1 [CRFR1], glucocorticoid receptor, tryptase, nerve growth factor, tyrosine kinase receptor A), and prevented mast cell activation. GLU upregulated the mRNA expression of intestinal transforming growth factor β. Conclusion: These findings indicate that GLU attenuates LPS-induced intestinal mucosal barrier injury, which is associated with modulating CRF signaling pathway. Objective: The purpose of this study was to evaluate the protection of glutamate (GLU) against the impairment in intestinal barrier function induced by lipopolysaccharide (LPS) stress in weaned pigs.Methods: Twenty-four weaned pigs were divided into four treatments containing: i) non-challenged control, ii) LPS-challenged control, iii) LPS+1.0% GLU, and iv) LPS+2.0% GLU. On day 28, pigs were treated with LPS or saline. Blood samples were collected at 0, 2, and 4 h post-injection. After blood samples collection at 4 h, all pigs were slaughtered, and spleen, mesenteric lymph nodes, liver and intestinal samples were obtained.Results: Dietary GLU supplementation inhibited the LPS-induced oxidative stress in pigs, as demonstrated by reduced malondialdehyde level and increased glutathione level in jejunum. Diets supplemented with GLU enhanced villus height, villus height/crypt depth and claudin-1 expression, attenuated intestinal histology and ultrastructure impairment induced by LPS. Moreover, GLU supplementation reversed intestinal intraepithelial lymphocyte number decrease and mast cell number increase induced by LPS stress. GLU reduced serum cortisol concentration at 4 h after LPS stress and downregulated the mRNA expression of intestinal corticotropin-releasing factor signal (corticotrophin-releasing factor [<i>CRF</i>], CRF receptor 1 [<i>CRFR1</i>], glucocorticoid receptor, tryptase, nerve growth factor, tyrosine kinase receptor A), and prevented mast cell activation. GLU upregulated the mRNA expression of intestinal transforming growth factor β.Conclusion: These findings indicate that GLU attenuates LPS-induced intestinal mucosal barrier injury, which is associated with modulating CRF signaling pathway.

Visual Tracking Using Improved Multiple Instance Learning with Co-training Framework for Moving Robot

( Zhiyu Zhou ),( Junjie Wang ),( Yaming Wang ),( Zefei Zhu ),( Jiayou Du ),( Xiangqi Liu ),( Jiaxin Quan ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.11

Object detection and tracking is the basic capability of mobile robots to achieve natural human-robot interaction. In this paper, an object tracking system of mobile robot is designed and validated using improved multiple instance learning algorithm. The improved multiple instance learning algorithm which prevents model drift significantly. Secondly, in order to improve the capability of classifiers, an active sample selection strategy is proposed by optimizing a bag Fisher information function instead of the bag likelihood function, which dynamically chooses most discriminative samples for classifier training. Furthermore, we integrate the co-training criterion into algorithm to update the appearance model accurately and avoid error accumulation. Finally, we evaluate our system on challenging sequences and an indoor environment in a laboratory. And the experiment results demonstrate that the proposed methods can stably and robustly track moving object.

전자부품 제작을 위한 3차원 프린팅 시스템 개발

신원수(Yuan-Zhu Xin),김완두(Wan Doo Kim),박수아(Su A Park),장혜련(Hye Ryeon Jang),석지민(Ji Min Seok),유준걸(JunJie Yu),이창우(Chang Woo Lee),이준희(Junhee Lee) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12

Simplified model prediction current control strategy for permanent magnet synchronous motor

Zhang, Housheng,Zhu, Shengjie,Jiang, Junjie,Wang, Qingzhuang,Wang, Ao,Jin, Duo The Korean Institute of Power Electronics 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.11

A simplified model predictive current control strategy based on mathematical auxiliary line method is proposed to increase the permanent magnet synchronous motor (PMSM) predictive current control system's steady-state performance while reducing the system's computational complexity. The mathematical models of current prediction, first-order compensation, and cost function are presented by analyzing the prediction current control strategy of the conventional models. Within a control cycle, the simplified model predictive current control algorithm applies two voltage vectors and omits the error calculation of cost function. The anticipated voltage of transformer obtained from the beat-free current control standard is considered the reference voltage, and the judgment of the area, where the reference voltage vector is found and the strategy for double voltage vector is selected, is put forward. The optimal voltage vector can be directly output without the error calculation of the cost function in the method, thereby effectively reducing the computation load and complexity of the system and improving the steady-state performance. Experimental results verify the validity and accuracy of the proposed simplified model of predictive current control strategy for PMSM control.