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- 저자 : Zhenchuan (검색결과 4 건)
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A New Modeling and Analysis Approach Based on State-Space Averaging for Converters
Zhenchuan Sun,Jiasheng Zhang 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.10
4-quadrant converters (4QCs) have been widely applied in power active VAR and harmonic compensators, FACTS, electric drive systems, and a variety of other applications. The state-space averaging model is usually quite facile and suitable for converter topologies with only two switch states, like half-bridge 4QC units. When directly used in topologies with multiple switch states, however, the modeling method becomes overly complicated. Due to this, plus the fact that multi-phase PWM 4QCs and even other varieties of converters are mostly multi-unit-symmetrical, a novel method is necessary. By researching the inner link between multi-phase topologies and half-bridge units, including inter-phase symmetry configurations, and control relations, this paper proposes a general unified modeling approach for application to multi-phase 4QCs. A series of conclusions are derived, alongside theoretical analysis of the model. The validity of the model and its theory is confirmed using single-phase and three-phase 4QCs and their numerical simulating waveforms as special cases. The proposed method may also extend to the modeling, analysis, and general research of other varieties of converter topologies.
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Nan Yao,Zhenchuan Song,Xinle Wang,Shan Yang,Heng Song 한국유방암학회 2017 Journal of breast cancer Vol.20 No.2
Purpose: Estrogen receptor (ER) and progesterone receptor (PR) have been used as indicators of endocrine system status since the mid-1970s in the clinical management of breast cancer. The predictive role of ER in endocrine therapy is undisputed, but the prognostic value of PR is still debated. The aim of this study was to investigate the clinical characteristics and prognosis of ER positive breast cancer with different PR expression levels. Methods: A population cohort of 3,030 primary invasive ER positive breast cancer patients from a single cancer center underwent surgery and received adjuvant endocrine therapy from 2004 to 2010. The clinical and biological features of these patients with high PR-expressing tumors were compared with those of patients with low PR-expressing tumors. The follow-up data for disease-free survival (DFS), overall survival (OS), and breast cancer specific survival (BCSS) was obtained from 2,778 patients. Cox regression analysis was used to correlate biomarkers and tumor characteristics with DFS, OS, and BCSS. Results: Tumors with low PR expression had more invasive pathological features and biological indexes than those with high PR expression. Low PR expression was an independent poor prognostic factor for DFS (p=0.014; hazard ratio [HR], 0.781; 95% confidence interval [CI], 0.641–0.950), OS (p=0.002; HR, 0.699; 95% CI, 0.560–0.873), and BCSS (p=0.005; HR, 0.714; 95% CI, 0.566–0.902). Furthermore, in low PR expressing tumors, patients who received chemotherapy had better DFS (p=0.002; HR, 0.449; 95% CI, 0.268–0.751), OS (p<0.001; HR, 0.341; 95% CI, 0.192–0.606), and BCSS (p<0.001; HR, 0.292; 95% CI, 0.156–0.549) than patients who did not received chemotherapy. Conclusion: Patients with ER positive invasive breast cancer with low PR expressing tumors have a worse prognosis than those with high PR expressing tumors, and these patients can benefit from chemotherapy.
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A Novel Pepper (Capsicum annuum L.) WRKY Gene, CaWRKY30, Is Involved in Pathogen Stress Responses
Zheng Jingyuan,Zou Xuexiao,Mao Zhenchuan,Xie Bingyan 한국식물학회 2011 Journal of Plant Biology Vol.54 No.5
WRKY proteins are a superfamily of transcription factors involved in many plant processes including plant defense responses to biotic and abiotic stresses. We isolated a WRKY gene from pepper during the incompatible interaction between the pepper cultivar HDA149 and Meloidogyne incognita. The full-length gene, named as CaWRKY30, has a 1,533-bp cDNA sequence and contains an open reading frame of 1,095 bp, encodes a putative polypeptide of 364 amino acids with a theoretical protein size of 41.2 kDa, and contains one WRKY domain followed by a zinc-finger motif. The genomic sequence of CaWRKY30 contains three exons and two introns. Southern blot analysis confirmed that CaWRKY30 exists as a single copy in the pepper cultivar HDA149 genome. Quantitative RT-PCR showed that CaWRKY30 is up-regulated by application of various pathogens including avirulent M. incognita, Tobacco mosaic virus, Ralstonia solanacerum,and Phytophthora capsici Leonian. Furthermore, the transcripts of CaWRKY30 were rapidly induced after treatment with phytohormones salicylic acid (SA). However, the expression of CaWRKY30 was down-regulated by virulent M. incognita and phytohormones methyl jasmonic acid (MeJA). In addition, the nuclear localization of CaWRKY30 was determined when a CaMV35s::CaWRKY30-eGFP fusion construct was expressed in onion epidermal cells. These results suggested that CaWRKY30might be involved in plant defense mechanisms against the diverse pathogen infection.
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Zhenxing Yang,Dongjiang Pan,Jianjun Zhou,Jian Chen,Zhenchuan Sun,Haining Liu 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.4
This paper conducts a simulation experiment research on cutter-head vibration characteristics by evaluating a soft-hard mixed stratum (the upper layer is silty soil, whereas the lower layer is moderately weathered granite of maximum uniaxial compressive strength (UCS) 142.0 MPa and slightly weathered granite of maximum 210.0 MPa). The ratios of hard rock and soil within the tunnel face were designed to be 1:1 and 1:2. Then, the cutter-head and stratum model were subjected to vibration analysis by reasonably deployed accelerometers. Results show that: 1) different conditions of heterogeneous strata mainly affected the acceleration amplitude and frequency distribution of cutter-head, in other words, the stronger hard rock, the larger the strength difference between the hard rock and soil within a tunnel face, the larger the vibration acceleration and the more concentrated the vibration frequency distribution; 2) the radial and circumferential vibration acceleration of the cutter-head in different positions were not largely different; however, axial accelerations were largely different. The axial vibration accelerations first increased and then decreased along the radial direction of cutter-head. Considering the difference between Multi-Mode Boring Test System and real cutter-head structure, the radius of joint between the cutter-head and the flange plate should be reasonably increased according to the ratio of hard rock in tunnel face; 3) with the increasing difference between the strength of the hard rock and soil, the circumferential and axial vibration acceleration multiplied. Thus, the soil remarkably reduces the vibration of the cutter-head. These results can provide some evidence of potential application for advancing manufacturing practice for cutter-head and disc cutter of shield machine.
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