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.

Precise visualization and ROS-dependent photodynamic therapy of colorectal cancer with a novel mitochondrial viscosity photosensitive fluorescent probe

Runsha Xiao,Fan Zheng,Kuo Kang,Lei Xiao,Anyao Bi,Yiting Chen,Qi Zhou,Xueping Feng,Zhikang Chen,Hao Yin,Wei Wang,Zihua Chen,Xiaomiao Cheng,Wenbin Zeng 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Colorectal cancer (CRC) is a prominent global cancer with high mortality rates among human beings. Efficient diagnosis and treatment have always been a challenge for CRC management. Fluorescence guided cancer therapy, which combines diagnosis with therapy into one platform, has brought a new chance for achieving precise cancer theranostics. Among this, photosensitizers, applied in photodynamic therapy (PDT), given the integration of real-time imaging capacity and efficacious treatment feasibility, show great potential to serve as remarkable tools. Although much effort has been put into constructing photosensitizers for locating and destroying CRC cells, it is still in high need to develop novel photosensitizers to attain specific detection and fulfil effective therapy. Methods Probe HTI was rational synthesized for the diagnosis and treatment of CRC. Spectrometric determination was carried out first, followed by the 1O2 generation ability test. Then, HTI was displayed in distinguishing CRC cells from normal cells Further, the PDT effect of the photosensitizer was studied in vitro. Additionally, HTI was used in CRC BALB/c nude mice model to validate its viscosity labelling and tumor suppression characteristics. Results We successfully fabricated a mitochondrial targeting probe, HTI, together with remarkable viscosity sensitivity, ultralow background interference, and excellent 1O2 generation capacity. HTI was favorably applied to the viscosity detection, displaying a 11-fold fluorescent intensity enhancement in solvents from 1.57 cp to 2043 cp. Then, it was demonstrated that HTI could distinguish CRC cells from normal cells upon the difference in mitochondrial viscosity. Moreover, HTI was qualified for producing 1O2 with high efficiency in cells, supported by the sparkling signals of DCFH after incubation with HTI under light irradiation. More importantly, the viscosity labelling and tumor suppression performance in CRC CDX model was determined, enriching the multifunctional validation of HTI in vivo. Conclusions In this study, HTI was demonstrated to show a sensitive response to mitochondrial viscosity and possess a high 1O2 generation capacity. Both in vitro cell imaging and in vivo tumor treatment trials proved that HTI was effectively served as a robust scaffold for tumor labeling and CRC cells clearance. This breakthrough discovery held immense potential for advancing the early diagnosis and management of CRC through PDT. By leveraging HTI’s properties, medical professionals could benefit from improved diagnostic accuracy and targeted treatment in CRC management, ultimately leading to enhanced patient outcomes.

A Control Strategy Based on Small Signal Model for Three-Phase to Single-Phase Matrix Converters

Chen, Si,Ge, Hongjuan,Zhang, Wenbin,Lu, Song The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

This paper presents a novel close-loop control scheme based on small signal modeling and weighted composite voltage feedback for a three-phase input and single-phase output Matrix Converter (3-1MC). A small non-polar capacitor is employed as the decoupling unit. The composite voltage weighted by the load voltage and the decoupling unit voltage is used as the feedback value for the voltage controller. Together with the current loop, the dual-loop control is implemented in the 3-1MC. In this paper, the weighted composite voltage expression is derived based on the sinusoidal pulse-width modulation (SPWM) strategy. The switch functions of the 3-1MC are deduced, and the average signal model and small signal model are built. Furthermore, the stability and dynamic performance of the 3-1MC are studied, and simulation and experiment studies are executed. The results show that the control method is effective and feasible. They also show that the design is reasonable and that the operating performance of the 3-1MC is good.

ANTI-PERIODIC SOLUTIONS FOR HIGHER-ORDER LIÉENARD TYPE DIFFERENTIAL EQUATION WITH p-LAPLACIAN OPERATOR

Chen, Taiyong,Liu, Wenbin Korean Mathematical Society 2012 대한수학회보 Vol.49 No.3

In this paper, by using degree theory, we consider a kind of higher-order Li$\acute{e}$enard type $p$-Laplacian differential equation as follows $$({\phi}_p(x^{(m)}))^{(m)}+f(x)x^{\prime}+g(t,x)=e(t)$$. Some new results on the existence of anti-periodic solutions for above equation are obtained.

A Microscopic Cohesive Zone Model and Effects of Interface on the Transverse Mechanical Properties for Composites

Wenbin Jia,Lei Fang,Zhi Chen,Kai Zhao,Hongmei Huang,Lei Pan 한국섬유공학회 2021 Fibers and polymers Vol.22 No.5

The carbon fiber/epoxy matrix interface plays an important role in the behavior and damage onset of unidirectionalfiber reinforced epoxy matrix composites and accurate modeling techniques are needed to study the effects of this complexregion on the composite response. In this work, a microscopic cohesive zone model (MCZM) based on atomic potentialenergy is established for the interface. A multiscale analysis method is proposed for predicting the transverse mechanicalproperties of unidirectional fiber composites: (1) At the microscale, MCZM is established for the interface; (2) At themesoscale, a unit cell model is established for the fiber, matrix and interface; and (3) At the macroscale, the homogenizationmethod, failure criteria and damage degradation models are used for predicting the transverse mechanical properties. Subsequently, the transverse mechanical properties and the damage evolution process are simulated with the multiscaleanalysis method. A comparison between the simulations and experiments shows that: (1) The maximum errors of thepredicted transverse modulus and transverse strength are -4.45 % and -1.28 %, respectively; and (2) MCZM can reflect thenonlinearity of epoxy matrix composite materials. Moreover, the effects of the interfacial strength on the macroscopictransverse mechanical properties and the damage onset are analysed. The simulation results show that: (1) The interfacialstrength has a more significant effect on the transverse strength and ultimate strain than on the transverse modulus; (2)Decreasing the interfacial strength has a greater effect on the transverse modulus, strength and ultimate strain than increasingthe interfacial strength; and (3) The interfacial strength can change the damage onset.

A Multiscale Analysis Method for Predicting the Transverse Mechanical Properties of Unidirectional Fibre-reinforced Composites

Wenbin Jia,Lei Fang,Zhi Chen,Kai Zhao,Hongmei Huang,Lei Pan 한국섬유공학회 2020 Fibers and polymers Vol.21 No.6

Mechanical property prediction methods for composites are very important as theoretical tools for engineeringstructural design. To more accurately capture the transverse mechanical properties of composites, a multiscale analysismethod is developed in this paper. The multiscale analysis method includes three scales: (1) At the microscale, a microscopiccohesive model based on atomic potential energy is established for the interface; (2) At the mesoscale, a unit cell model isestablished for the fibre, matrix and interface; and (3) At the macroscale, the homogenization method, failure criteria anddamage degradation models are used for predicting the transverse mechanical properties. Subsequently, the transversemechanical properties and the damage evolution process are simulated with the multiscale analysis method. A comparisonbetween the simulations and experiments shows that the maximum error of the predicted transverse modulus and transversestrength is -4.45 % and -12.05 %, respectively. Finally, the effects of the interfacial strength on the macroscopic transversemechanical properties and the damage onset are analysed. The following conclusions are drawn from the simulation results:(1) The interfacial strength has a more significant effect on the transverse strength and ultimate strain than on the transversemodulus; (2) Decreasing the interfacial strength has a greater effect on the transverse modulus, strength and ultimate strainthan increasing the interfacial strength; and (3) The interfacial strength can change the damage onset.

Effects of Length and Oxidation of Multi-walled Carbon Nanotubes on the Mechanical and Electrical Properties for Epoxy Matrix Composites

Wenbin Jia,Zhi Chen,Lei Fang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.5

This work investigated the effects of length and oxidation of multiwalled carbon nanotubes (CNTs) on theinterfacial strength, fracture toughness enhancement and conductivity for epoxy matrix composites by experiment. Firstly, aseven-step processing scheme was proposed to obtain highly dispersed CNT-epoxy composites. Subsequently, two feasiblemethods were presented to characterize the interfacial strength and used to study the effects of length and oxidation of CNTson the interfacial strength. Thirdly, based on the experimental results of the fracture toughness of CNT-epoxy composites, weproposed a new fracture theory for CNT-based composites which is contrary to the conventional fracture theory for fiberbasedcomposites. The experimental results show that the fracture toughness enhancement reaches maximum at the criticaloxidation time, when the interfacial strength equals CNT strength. At last, to obtain CNT-epoxy composites with both highmechanical and electrical properties, a feasible solution was put forward.

Assessment of Population Structure and Genetic Diversity of 15 Chinese Indigenous Chicken Breeds Using Microsatellite Markers

Chen, Guohong,Bao, Wenbin,Shu, Jingting,Ji, Congliang,Wang, Minqiang,Eding, Herwin,Muchadeyi, Farai,Weigend, Steffen Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.3

The genetic structure and diversity of 15 Chinese indigenous chicken breeds was investigated using 29 microsatellite markers. The total number of birds examined was 542, on average 36 birds per breed. A total of 277 alleles (mean number 9.55 alleles per locus, ranging from 2 to 25) was observed. All populations showed high levels of heterozygosity with the lowest estimate of 0.440 for the Gushi chickens, and the highest one of 0.644 observed for Wannan Three-yellow chickens. The global heterozygote deficit across all populations (FIT) amounted to 0.180 (p<0.001). About 16% of the total genetic variability originated from differences between breeds, with all loci contributing significantly to this differentiation. An unrooted consensus tree was constructed using the Neighbour-Joining method and pair-wise distances based on marker estimated kinships. Two main groups were found. The heavy-body type populations grouped together in one cluster while the light-body type populations formed the second cluster. The STRUCTURE software was used to assess genetic clustering of these chicken breeds. Similar to the phylogenetic analysis, the heavy-body type and light-body type populations separated first. Clustering analysis provided an accurate representation of the current genetic relations among the breeds. Remarkably similar breed rankings were obtained with all methods.

THE EXISTENCE AND MULTIPLICITY OF SOLUTIONS TO p-LAPLACE EQUATION WITH PERIODIC BOUNDARY CONDITIONS

Chen, Taiyong,Liu, Wenbin,Zhang, Jianjun,Zhang, Huixing The Korean Society for Computational and Applied M 2009 Journal of applied mathematics & informatics Vol.27 No.3

In this paper, we consider p-Laplace equation which models the turbulent flow in a porous medium. Using a continuation principle (cf. [R. $Man{\acute{a}}sevich$ and J. Mawhin, Periodic solutions for nonlinear systems with p-Lplacian-like operators, J. Diff. Equa. 145(1998), 367-393]), we prove the existence of solutions for p-Laplace equation subject to periodic boundary conditions, under some sign and growth conditions for f. With the help of Leray-Schauder degree theory, the multiplicity of periodic solutions for p-Laplace equation is obtained under the similar conditions above and some known results are improved.

Fault-tolerant Control for Uncertain Vehicle Active Steering Systems with Time-delay and Actuator Fault

Lin Chen,Xiaomeng Li,Wenbin Xiao,Panshuo Li,Qi Zhou 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.9

In this paper, the fuzzy control problem for uncertain time-delay active steering systems with actuator fault is investigated. Due to the variation of vehicle mass, Takagi-Sugeno fuzzy model is introduced to describe the uncertainties by employing the sector nonlinearity method. In the process of signal transmission, the network-induced delay and packet dropouts are unavoidable. To handle this problem, a robust H∞ controller is designed to regulate the vehicle lateral motion. A fault-tolerant controller is designed to reduce the impact of actuator fault on the vehicle active steering systems. Based on the Lyapunov stability theory, sufficient conditions are established to ensure that the resulting closed-loop system is asymptotically stable with the prescribed H∞ performance. Simulation results are provided to confirm the effectiveness and applicability of the proposed control scheme.