SiC IGBT degradation mechanism investigation under HV‑H3TRB tests

Ziming Wu,Zongbei Dai,Jian Zhou,Huafeng Dong,Wencan Wang,Feiwan Xie,Haoran Wang,Jiahui Yan,Xiyu Chen,Shaohua Yang,Fugen Wu 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.2

The high voltage-high humidity-high temperature reverse bias (HV-H3TRB) test was utilized to evaluate the reliability of silicon carbide insulated gate bipolar transistors (SiC IGBTs). Moisture invasion often induces termination/passivation and metal corrosion. Therefore, the HV-H3TRB test is generally used to assess termination / passivation robustness. However, under the HV-H3TRB test conditions, gate quality degradation may occur. In this study, the dominant degradation mechanism of SiC IGBTs was investigated. The changes of the most sensitive static characteristics (e.g., threshold voltage, breakdown voltage, and leakage current) were recorded. The threshold voltage decreased and leakage current increased substantially after > 1000 h of HV-H3TRB tests under 85 ℃/85% RH climate conditions. Capacitance-voltage (C-V) curve measurements indicated that the mobile ions at the SiC/SiO2 interface or in the gate oxide likely caused the threshold-voltage instability in the SiC IGBTs after the HV-H3TRB tests. This instability can be recovered by applying a negative gate bias. Subsequent failure analysis confirmed no corrosion of metals or termination/passivation in the device, which indicates the robustness of the passivation (consisting of phosphor-silicate glass and Si3N4). Therefore, the gate quality appears to be a significant reliability risk for SiC IGBTs under high humidity, high temperature, and high voltage conditions.

STRONG CONVERGENCE THEOREMS OF COMMON ELEMENTS FOR EQUILIBRIUM PROBLEMS AND FIXED POINT PROBLEMS IN BANACH SPACES

Ziming Wang,Yongfu Su 한국전산응용수학회 2010 Journal of applied mathematics & informatics Vol.28 No.3

We introduce a new iterative algorithm for equilibrium and fixed point problems of three hemi-relatively nonexpansive mappings by the CQ hybrid method in Banach spaces, Our results improve and extend the corresponding results announced by Xiaolong Qin, Yeol Je Cho, Shin Min Kang [Xiaolong Qin, Yeol Je Cho, Shin Min Kang, Convergence theorems of common elements for equilibrium problems and fixed point problems in Banach spaces, Journal of Computational and Applied Mathematics 225(2009) 20-30], P. Kumam, K. Wattanawitoon [P. Kumam, K. Wattanawitoon, Convergence theorems of a hybrid algorithm for equilibrium problems, Nonlinear Analysis: Hybrid Systems (2009),doi:10.1016/j.nahs.2009.02.006], W. Takahashi, K. Zembayashi [W. Takahashi, K. Zembayashi, Strong convergence theorem by a new hybrid method for equilibrium problems and relatively nonexpansive mappings, Fixed Point Theory Appl. (2008) doi:10.1155 /2008/528476]and others therein.

Voices from Public Assembly Trumpets: Sound Tool and Student Movement in Republican China

Xu, Ziming East-Asian Society for Urban History 2020 Journal of east-asian urban history Vol.2 No.2

In recent years, the studies on the student movement in Republican China have been more accurate. However, some areas still remain uncovered, such as the technology of student movement. In this paper, the author focuses on how students utilize sound tools in their movements, especially in public meetings. During the May 4^th Movement and the 1920s, Chinese students mainly used speaking trumpets without electricity. In the 1930s, electric tools began to appear in student movement for sound propagation. In the student movement of postwar China, students of various political positions could make a use of loudspeaker, wired broadcasting, and megaphone or other equipments. The battle of sound had been part of the Chinese civil war. In general, sound tools had taken an important role in the history of student radicalism.

Mechanical overload-induced release of extracellular mitochondrial particles from tendon cells leads to inflammation in tendinopathy

Chen Ziming,Li Mengyuan,Chen Peilin,Tai Andrew,Li Jiayue,Bassonga Euphemie Landao,Gao Junjie,Liu Delin,Wood David,Kennedy Brendan F.,Zheng Qiujian,Zheng Ming H. 생화학분자생물학회 2024 Experimental and molecular medicine Vol.56 No.-

Tendinopathy is one of the most common musculoskeletal diseases, and mechanical overload is considered its primary cause. However, the underlying mechanism through which mechanical overload induces tendinopathy has not been determined. In this study, we identified for the first time that tendon cells can release extracellular mitochondria (ExtraMito) particles, a subtype of medium extracellular particles (mEPs), into the environment through a process regulated by mechanical loading. RNA sequencing systematically revealed that oxygen-related reactions, extracellular particles, and inflammation were present in diseased human tendons, suggesting that these factors play a role in the pathogenesis of tendinopathy. We simulated the disease condition by imposing a 9% strain overload on three-dimensional mouse tendon constructs in our cyclic uniaxial stretching bioreactor. The three-dimensional mouse tendon constructs under normal loading with 6% strain exhibited an extended mitochondrial network, as observed through live-cell confocal laser scanning microscopy. In contrast, mechanical overload led to a fragmented mitochondrial network. Our microscopic and immunoblot results demonstrated that mechanical loading induced tendon cells to release ExtraMito particles. Furthermore, we showed that mEPs released from tendon cells overloaded with a 9% strain (mEP9%) induced macrophage chemotaxis and increased the production of proinflammatory cytokines, including IL-6, CXCL1, and IL-18, from macrophages compared to mEP0%, mEP3%, and mEP6%. Partial depletion of the ExtraMito particles from mEP9% by magnetic-activated cell sorting significantly reduced macrophage chemotaxis. N-acetyl-L-cysteine treatment preserved the mitochondrial network in overloaded tendon cells, diminishing overload-induced macrophage chemotaxis toward mEP9%. These findings revealed a novel mechanism of tendinopathy; in an overloaded environment, ExtraMito particles convey mechanical response signals from tendon cells to the immune microenvironment, culminating in tendinopathy.

Integrative analysis of multi-dimensional imaging genomics data for Alzheimer's disease prediction

Zhang, Ziming,Huang, Heng,Shen, Dinggang Frontiers Media S.A. 2014 FRONTIERS IN AGING NEUROSCIENCE Vol.6 No.-

<P>In this paper, we explore the effects of integrating multi-dimensional imaging genomics data for Alzheimer's disease (AD) prediction using machine learning approaches. Precisely, we compare our three recent proposed feature selection methods [i.e., multiple kernel learning (MKL), high-order graph matching based feature selection (HGM-FS), sparse multimodal learning (SMML)] using four widely-used modalities [i.e., magnetic resonance imaging (MRI), positron emission tomography (PET), cerebrospinal fluid (CSF), and genetic modality single-nucleotide polymorphism (SNP)]. This study demonstrates the performance of each method using these modalities individually or integratively, and may be valuable to clinical tests in practice. Our experimental results suggest that for AD prediction, in general, (1) in terms of accuracy, PET is the best modality; (2) Even though the discriminant power of genetic SNP features is weak, adding this modality to other modalities does help improve the classification accuracy; (3) HGM-FS works best among the three feature selection methods; (4) Some of the selected features are shared by all the feature selection methods, which may have high correlation with the disease. Using all the modalities on the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset, the best accuracies, described as (mean ± standard deviation)%, among the three methods are (76.2 ± 11.3)% for AD vs. MCI, (94.8 ± 7.3)% for AD vs. HC, (76.5 ± 11.1)% for MCI vs. HC, and (71.0 ± 8.4)% for AD vs. MCI vs. HC, respectively.</P>

STRONG CONVERGENCE THEOREMS OF COMMON ELEMENTS FOR EQUILIBRIUM PROBLEMS AND FIXED POINT PROBLEMS IN BANACH SPACES

Wang, Ziming,Su, Yongfu The Korean Society for Computational and Applied M 2010 Journal of applied mathematics & informatics Vol.28 No.3

We introduce a new iterative algorithm for equilibrium and fixed point problems of three hemi-relatively nonexpansive mappings by the CQ hybrid method in Banach spaces, Our results improve and extend the corresponding results announced by Xiaolong Qin, Yeol Je Cho, Shin Min Kang [Xiaolong Qin, Yeol Je Cho, Shin Min Kang, Convergence theorems of common elements for equilibrium problems and fixed point problems in Banach spaces, Journal of Computational and Applied Mathematics 225 (2009) 20-30], P. Kumam, K. Wattanawitoon [P. Kumam, K. Wattanawitoon, Convergence theorems of a hybrid algorithm for equilibrium problems, Nonlinear Analysis: Hybrid Systems (2009), doi:10.1016/j.nahs.2009.02.006], W. Takahashi, K. Zembayashi [W. Takahashi, K. Zembayashi, Strong convergence theorem by a new hybrid method for equilibrium problems and relatively nonexpansive mappings, Fixed Point Theory Appl. (2008) doi:10.1155/2008/528476] and others therein.

AN ITERATIVE SCHEME FOR EQUILIBRIUM PROBLEMS AND FIXED POINT PROBLEMS OF ASYMPTOTICALLY k-STRICT PSEUDO-CONTRACTIVE MAPPINGS

Wang, Ziming,Su, Yongfu Korean Mathematical Society 2010 대한수학회논문집 Vol.25 No.1

In this paper, we propose an iterative scheme for finding a common element of the set of solutions of an equilibrium problem and the set of fixed points of an asymptotically k-strict pseudo-contractive mapping in the setting of real Hilbert spaces. We establish some weak and strong convergence theorems of the sequences generated by our proposed scheme. Our results are more general than the known results which are given by many authors. In particular, necessary and sufficient conditions for strong convergence of our iterative scheme are obtained.

The Multiformity of Asian Music: A Comparative Study on Current situation Between Indian, Chinese and Philippine Music

Chen,Ziming 아시아음악학회 2003 Asian Musicology Vol.3 No.-

Remarkably low genetic diversity and shallow population structure detected of the spiny eel (Sinobdella sinensis) in Eastern China

Sheng Yuan,Meijian Liu,Ziming Zhao 한국유전학회 2020 Genes & Genomics Vol.42 No.11

Background The spiny eel (Sinobdella sinensis) is a small subtropical fish endemic to China, Vietnam, and Laos. It hasdisappeared in many rivers and lakes due to anthropogenic stressors. Objective The aim of this study was to investigate the genetic diversity and population structure and to provide pertinentinformation of the evolutionary history and conservation of S. sinensis. Methods Mitochondrial DNA (mtDNA) cytochrome c oxidase I (COI) sequences of 144 individuals from five lakes in theJiangsu Province of Eastern China were sequenced. Results A total of 17 haplotypes were defined by 20 variable nucleotide sites. Remarkably low haplotype and nucleotidediversity was observed in all sampled populations. The AMOVA analyses revealed that 96.44% of the genetic variationoccurred within the populations. Significant genetic differentiation was detected among populations (P < 0.05), but nolarge-scale regional differences were detected. Analysis of neutral evolution and mismatch distribution suggests populationexpansion. Low genetic diversity and shallow population structure based on COI sequences were also confirmed. Conclusions The wild resource of S. sinensis in Eastern China has sharply declined. Low genetic diversity and shallowpopulation structure based on COI sequences were confirmed. Fishing management and resource conservation of this speciesshould be taken urgently.

Chloride diffusion in concrete associated with single, dual and multi cation types

Zijian Song,Linhua Jiang,Ziming Zhang 사단법인 한국계산역학회 2016 Computers and Concrete, An International Journal Vol.17 No.1

Currently, most of the investigations on chloride diffusion were based on the experiments and simulations concerning single cation type chlorides. Chloride diffusion associated with dual or multi cation types was rarely studied. In this paper, several groups of diffusion experiments are conducted using chloride solutions containing single, dual and multi cation types. A multi-ionic model is also proposed to simulate the chloride diffusion behavior in the experimental tests. The MATLAB software is used to numerically solve the nonlinear PDEs in the multi-ionic model. The experimental and simulated results show that the chloride diffusion behavior associated with different cation types is significantly different. When the single cation type chlorides are adopted, it is found that the bound rates of chloride ions combined with divalent cations are greater than those combined with monovalent cations. When the dual/multi cation type chlorides are adopted, the chloride bound rates increase with the Ca2+/Mg2+ percentage in the source solutions. This evidence indicates that the divalent cations would markedly enhance the chloride binding capacity and reduce the chloride diffusivity. Moreover, on the basis of the analysis, it is also found that the complicated cation types in source solutions are beneficial to reducing the chloride diffusivity.