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Mechanical Properties and Microstructure of Lime-Treated Red Clay
Lijie Chen,Xuejun Chen,He Wang,Xiang Huang,Yu Song 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.1
This research conducted a triaxial test on lime-treated clay with different contents to analyze the effect of mechanical properties. Scanning electron microscope (SEM) and low-field nuclear magnetic resonance (NMR) analysis were used to analyze the effect. X-ray diffraction (XRD) was used to analyze the chemical changes of calcium oxide on red clay. The results show that with the increase of calcium oxide content, the strength increases, and it can be increased by 282% at 200 kPa confining pressure. The calcium oxide in the red clay reactedwith the water in the soil to form calcium hydroxide. The alkaline environment will erode the edge of the soil particles and cause pores to become larger. SEM observed that the addition of calcium oxide caused the agglomeration of soil particles and changed the pore structure of red clay. Low-field NMR showed that calcium oxide had a significant effect on the pore structure of red clay. Calcium oxide increased the total pore volume of the soil sample. Calcium oxide had a substantial influence on the three pore distribution ranges, I (1.1 − 11 μm), II (15 − 137 μm), and III (137 − 512 μm). The porosity fitted with shear strength, it negatively correlated with I and III, and positively correlated with II.
IGCT Self-Protection Strategy for IGCT Converters
Hong Zeng,Xiulin Chen,Yongmin Chen,Xuejun Pan,Shunbiao Zhang,Fanglin Chen,Wenbin Zeng 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
The high-power semiconductor IGCT is widely used in two-level or three-level IGCT converters and for these converters a comprehensive system-protection strategy may be used to protect the IGCT. But there are still some problems resulted from signal transmission delays, such as incorrect timing, low response speeds, second breakdown and those problems can result in IGCT overload failure, bridge-arm shoot-through and other consequences. In this paper, the anode voltage and current parameters gained from the IGCT device are studied as protection reference in a new GCT gate drive unit. The gate drive unit can control and process the signal logic, and execute safe and reliable switching action. The signal is simultaneously feed back to the host computer in IGCT converters to perform the switching control of other devices. This new gate unit can effectively reduce device failure rates and improve the reliability of IGCT converters systems, while reducing operating costs.
Research on Urban Traffic Optimal Path Planning Method based on Improved Genetic Algorithm
Xuejun Liu,Yihan Chen 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.10
The traditional genetic algorithm randomly selects nodes in two chromosomes for crossover operation, which may result in individuals of disconnected or loop circuit and lead to issues as meaningless crossover operations. In order to increase the diversity of the population and prevent the occurrence of premature mutation algorithm which might cause local convergence, this essay presents a new urban traffic optimal path planning method. Initialized from the improvement of population genetic algorithm, it designs the fitness function and optimizes crossover and mutation operators so that the optimal or near-optimal solution can be quickly figured out. Moreover, the Matlab software simulation test exhibits the feasibility and effectiveness of the method.
Enlarging the Terminal Region of Quasi-infinite Horizon NMPC Based on T-S Fuzzy Model
Shuyou Yu,Hong Chen,Xuejun Li 제어·로봇·시스템학회 2009 International Journal of Control, Automation, and Vol.7 No.3
The paper presents a method for enlarging the terminal region of quasi-infinity horizon nonlinear model predictive control (NMPC) for nonlinear systems with constraints. The main technique builds on the fact that terminal controllers are fictitious and never applied to the system in the quasi-infinite horizon NMPC [1]. Based on T-S fuzzy models of nonlinear systems, we show that a parameter-dependent state feedback law exists such that the corresponding value function and its level set can be served as terminal cost and terminal region. The problem of maximizing the terminal region is formulated as a convex optimization problem based on linear matrix inequalities (LMIs). A numerical example is given to illustrate the effectiveness of the proposed method.
Sipeng Li,Jialing Chen,Xuanjun Zhang,Zhaoyang Ding,Xuejun Cao 한국생물공학회 2018 Biotechnology and Bioprocess Engineering Vol.23 No.1
Microbial transglutaminase (MTG) has been widely used in the food and pharmaceuticals industries. In this study, MTG was purified using affinity precipitation with an affinity polymer (PMMDN-T), which was synthesized using a pH-responsive polymer (PMMDN) coupled with L-thyroxin as an affinity ligand. Interactions between MTG and PMMDN-T were investigated using turbidimetric titration, zeta potential measurements, and low-field nuclear magnetic resonance (LF-NMR). We found different behaviors, architectures, and phase states of pH-dependent interactions between MTG and PMMDN-T interactions. Binding energetics between MTG and PMMDN-T were determined by isothermal titration calorimetry (ITC). The isoelectric point (pI) of the affinity polymer was 4.65 and was recovered with 96.7% efficiency after recycling the polymer three times. The optimal adsorption condition was 0.02 mol/L phosphate buffer (pH 6.0) with 1.0 mol/L NaCl at 30.0°C and a ligand density of 50.0 μmol/g. The maximum elution recoveries of total MTG were 98.44% (protein) with 92.19% (activity) using 0.02 mol/L pH 10.0 Gly-NaOH as the eluent.
Identification of Glycine Max MicroRNAs in Response to Phosphorus Deficiency
Aihua Sha,Yinhua Chen,Hongping Ba,Zhihui Shan,Xiaojuan Zhang,Xuejun Wu,Dezheng Qiu,Shuilian Chen,Xinan Zhou 한국식물학회 2012 Journal of Plant Biology Vol.55 No.4
MicroRNAs (miRNAs) are endogenous small RNAs regulating plant development and stress responses. In addition, phosphorus (P) is an important macronutrient for plant growth and development. More than two hundred miRNAs have been identified in Glycine Max and a few of miRNAs have been shown to respond to P deficiency,however, whether there are other miRNAs involved in P deficiency response is largely unknown. In this study, we used high-throughput small RNA sequencing and wholegenome-wide mining to identify the potential miRNAs in response to P deficiency. After sequencing, we deduced 183known, 99 conserved and 126 novel miRNAs in Glycine Max. Among them, in response to P deficiency, the expressions of 27 known, 16 conserved and 12 novel miRNAs showed significant changes in roots, whereas the expressions of 34known, 14 conserved and 7 novel miRNAs were significantly different in shoots. Furthermore, we validated the predicated novel miRNAs and found that three miRNAs in roots and five miRNAs in shoots responded to P deficiency. Some miRNAs were P-induced whereas some were P-suppressed. Together these results indicated that the miRNAs identified might play important roles in regulating P signaling pathway.
Jing Ma,Suhe Dong,Hongtao Lu,Zhongmin Chen,Huijie Yu,Xuejun Sun,Renjun Peng,Wei Li,Sinian Wang,Qisheng Jiang,Fengsheng Li,Li Ma 한국생체재료학회 2022 생체재료학회지 Vol.26 No.2
Objective: This study aimed to reveal the protective effect of hydrogen storage nanomaterial MgH2 on radiationinduced male fertility impairment. Methods: The characterization of MgH2 were analyzed by scanning electron microscopy (SEM) and particle size analyzer. The safety of MgH2 were evaluated in vivo and in vitro. The radioprotective effect of MgH2 on the reproductive system were analyzed in mice, including sperm quality, genetic effect, spermatogenesis, and hormone secretion. ESR, flow cytometry and western blotting assay were used to reveal the underlying mechanisms. Results: MgH2 had an irregular spherical morphology and a particle size of approximately 463.2 nm, and the content of Mg reached 71.46%. MgH2 was safe and nontoxic in mice and cells. After irradiation, MgH2 treatment significantly protected testicular structure, increased sperm density, improved sperm motility, reduced deformity rates, and reduced the genetic toxicity. Particularly, the sperm motility were consistent with those in MH mice and human semen samples. Furthermore, MgH2 treatment could maintain hormone secretion and testicular spermatogenesis, especially the generation of Sertoli cells, spermatogonia and round sperm cells. In vitro, MgH2 eliminated the [·OH], suppressed the irradiation-induced increase in ROS production, and effectively alleviated the increase in MDA contents. Moreover, MgH2 significantly ameliorated apoptosis in testes and cells and reversed the G2/M phase cell cycle arrest induced by irradiation. In addition, MgH2 inhibited the activation of radiation-induced inflammation and pyroptosis. Conclusion: MgH2 improved irradiation-induced male fertility impairment by eliminating hydroxyl free radicals.
The Comprehensive Recognition Method of Critical Lines Based on the Principal Component Analysis
Hao Guangtao,Lin Zhenheng,Wu Xuanyi,Chen Xuejun 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.5
Accurate identification of a few key lines in power system is of great significance to prevent blackout. Traditional key lines are mainly identified by single index such as power grid structure, line load rate and active power of line, which is one-sided. Therefore, in the wide area measurement environment, a multi-dimensional comprehensive identification method of key lines based on principal component analysis is proposed. Firstly, from the aspect of transmission breadth and depth, the utilization index of line is proposed. Secondly, the grid structure, line load rate and line active power index are proposed. Thirdly, based on principal component analysis, a comprehensive identification method of the above four indicators is proposed. Finally, taking the actual power grid as an example, the accuracy of this method is verified by comparing with the traditional method.