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.

Is the Poor Quality of Chinese Civic Awareness Preventing Democracy in China? A Case Study of Zeguo Township

Zhenhua Su,Junjie Le,Jun Ma 경남대학교 극동문제연구소 2012 ASIAN PERSPECTIVE Vol.36 No.1

A prevailing view in China is that the country cannot democratize because of the poor quality of the populace with respect to "citizen quality," or civic awareness. This viewpoint lacks empirical support in relevant case studies and databases. This article focuses on a case study conducted using the deliberative polling process in Zeguo Township, Zhejiang Province, to determine whether citizen quality influences the effectiveness of local democratic action.We find that Mduring the group democratic deliberation, factors such as participants` education, age, and career do not bear significantly on the success of democratic deliberation. Democratic deliberation can improve the civic knowledge of the public, public spiritedness, and civic participation, all of which facilitate the effectiveness of deliberation and the development of trust in the government.

Novel Dead-time Segmented Compensation Strategy for a Wide Impedance Angle Range in a Three-phase Inverter with a Resistance-Inductance Load

Zhang Siyan,Wang Xudong,Ma Junjie,Duan Ruizhen,Zhou Kai 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.4

The dead-time setting in space vector pulse width modulation (SVPWM) causes inverter output waveform distortion and performance degradation. This paper proposes a novel dead-time segmented compensation strategy for a wide impedance angle range in a three-phase inverter with a resistance-inductance load. Since the load impedance angle ( φ ) of the threephase inverter produces diff erent dead-time eff ects, in this paper, it is divided into two intervals of [0 30°] and [30° 90°] and a corresponding dead-time segmented compensation strategy is proposed, which solves the limitation of the traditional time compensation scheme that analyzes only the resistive load. In addition, this paper uses the conversion relationship between the power factor ( λ ) and φ to determine the current polarity of each sector in the vector space, which avoids the detection error of the current zero-crossing point in the traditional compensation scheme. The simulation and experimental results demonstrate that this method eff ectively reduces the total harmonic distortion (THD) of the inverter output current signal by approximately 30% and is easy to program, which improves the inverter output performance.

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.

Hong Kong Medical Journal – the Premier General Medical Journal in Hong Kong

Li Kenneth KW,Ma Edmond SK,Lui Rashid NS,Huang Junjie,Xue Hao,Wong Martin CS 대한의학회 2021 Journal of Korean medical science Vol.36 No.31

Comparison of Conventional DC-DC Converter and a Family of Diode-Assisted DC-DC Converter in Renewable Energy Applications

Zhang, Yan,Liu, Jinjun,Ma, Xiaolong,Feng, Junjie The Korean Institute of Power Electronics 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.2

In the conventional dc-dc converter, a pair of additional diode and the adjacent passive component capacitor/inductor can be added to the circuit with an X-shape connection, which generates a family of new topologies. The novel circuits, also called diode-assisted dc-dc converter, enhance the voltage boost/buck capability and have a great potential for high step-up/step-down power conversions. This paper mainly investigates and compares conventional dc-dc converter and diode-assisted dc-dc converter in wide range power conversion from the aspects of silicon devices, passive components requirements, electro-magnetic interference (EMI) and efficiency. Then, a comprehensive comparison example of a high step-up power conversion system was carried out. The two kinds of boost dc-dc converters operate under the same operation conditions. Mathematical analysis and experiment results verify that diode-assisted dc-dc converters are very promising for simultaneous high efficiency and high step-up/step-down power conversion in distributed power supply systems.

Effects of Nitrogen Concentration on Root Respiration Rate and Nonstructural Carbohydrates of Walnut Seedlings

Chunping Li,Shiwei Wang,Cuifang Zhang,Junjie Ding,Bin Ma,Rabigul Yasin,Zezheng Xue 한국원예학회 2020 원예과학기술지 Vol.38 No.3

Nitrogen is a critical determinant of forest growth and productivity, and root respiration rate and nonstructural carbohydrates are important parameters for evaluating the effects of supplied nutrients. Here, we assessed the effects of nitrogen on walnut seedlings (Juglans regia Linn.) that grew consistently for a year under favorable conditions. Seedlings were potted in seven concentrations of N availability, 0, 1, 2, 4, 8, 12, and 16 mmol·L1, and the specific root respiration rate and nonstructural carbohydrate content of the root system were determined via the offbody root system and the ketone color ratio methods, respectively. Nitrogen concentration was positively correlated with specific root respiration, and root diameter was the main factor related to specific root respiration and nonstructural carbohydrate content of walnut seedlings. Under the same nitrogen concentrations, the soluble total sugar and starch content of roots increased with increasing root diameter, while the specific root respiration increased with decreasing root diameter. Compared to the 0 mmol·L1 nitrogen concentration, the content of nonstructural carbohydrates in the root system and the specific root respiration were higher when nitrogen concentration was N16. Our comprehensive analysis showed that a nitrogen concentration of N16 improved the respiration rate of the seedling root system, significantly increased the content of nonstructural carbohydrates in the seedling root system, and effectively promoted the growth and development of the seedling root system of walnut seedlings.

Comparison of Conventional DC-DC Converter and a Family of Diode-Assisted DC-DC Converter in Renewable Energy Applications

Yan Zhang,Jinjun Liu,Xiaolong Ma,Junjie Feng 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.2

In the conventional dc-dc converter, a pair of additional diode and the adjacent passive component capacitor/inductor can be added to the circuit with an X-shape connection, which generates a family of new topologies. The novel circuits, also called diode-assisted dc-dc converter, enhance the voltage boost/buck capability and have a great potential for high step-up/step-down power conversions. This paper mainly investigates and compares conventional dc-dc converter and diode-assisted dc-dc converter in wide range power conversion from the aspects of silicon devices, passive components requirements, electro-magnetic interference (EMI) and efficiency. Then, a comprehensive comparison example of a high step-up power conversion system was carried out. The two kinds of boost dc-dc converters operate under the same operation conditions. Mathematical analysis and experiment results verify that diode-assisted dc-dc converters are very promising for simultaneous high efficiency and high step-up/step-down power conversion in distributed power supply systems.

An MRTF-A–ZEB1–IRF9 axis contributes to fibroblast–myofibroblast transition and renal fibrosis

Zhao Qianwen,Shao Tinghui,Zhu Yuwen,Zong Gengjie,Zhang Junjie,Tang Shifan,Lin Yanshan,Ma Hongzhen,Jiang Zhifan,Xu Yong,Wu Xiaoyan,Zhang Tao 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

Myofibroblasts, characterized by the expression of the matricellular protein periostin (Postn), mediate the profibrogenic response during tissue repair and remodeling. Previous studies have demonstrated that systemic deficiency in myocardin-related transcription factor A (MRTF-A) attenuates renal fibrosis in mice. In the present study, we investigated the myofibroblast-specific role of MRTF-A in renal fibrosis and the underlying mechanism. We report that myofibroblast-specific deletion of MRTF-A, achieved through crossbreeding Mrtfa-flox mice with Postn-CreERT2 mice, led to amelioration of renal fibrosis. RNA-seq identified zinc finger E-Box binding homeobox 1 (Zeb1) as a downstream target of MRTF-A in renal fibroblasts. MRTF-A interacts with TEA domain transcription factor 1 (TEAD1) to bind to the Zeb1 promoter and activate Zeb1 transcription. Zeb1 knockdown retarded the fibroblast–myofibroblast transition (FMyT) in vitro and dampened renal fibrosis in mice. Transcriptomic assays showed that Zeb1 might contribute to FMyT by repressing the transcription of interferon regulatory factor 9 (IRF9). IRF9 knockdown overcame the effect of Zeb1 depletion and promoted FMyT, whereas IRF9 overexpression antagonized TGF-β-induced FMyT. In conclusion, our data unveil a novel MRTF-A–Zeb1–IRF9 axis that can potentially contribute to fibroblast–myofibroblast transition and renal fibrosis. Screening for small-molecule compounds that target this axis may yield therapeutic options for the mollification of renal fibrosis.

Micro Galvanic Cell To Generate PtO and Extend the Triple-Phase Boundary during Self-Assembly of Pt/C and Nafion for Catalyst Layers of PEMFC

Long, Zhi,Gao, Liqin,Li, Yankai,Kang, Baotao,Lee, Jin Yong,Ge, Junjie,Liu, Changpeng,Ma, Shuhua,Jin, Zhao,Ai, Hongqi American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.44

<P>The self-assembly powder (SAP) with varying Nafion content was synthesized and characterized by XRD, XPS, HRTEM, and mapping. It is observed that the oxygen from oxygen functional groups transfers to the surface of Pt and generate PtO during the process of self-assembly with the mechanism of micro galvanic cell, where Pt, carbon black, and Nafion act as the anode, cathode and electrolyte, respectively. The appearance of PtO on the surface of Pt leads to a turnover of Nafion structure, and therefore more hydrophilic sulfonic groups directly contact with Pt, and thus the triple-phase boundary (TPB) has been expanded.</P>