Family of Dual-Input Dual-Buck Inverters Based on Dual-Input Switching Cells

Yang, Fan,Ge, Hongjuan,Yang, Jingfan,Dang, Runyun,Wu, Hongfei The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.4

A family of dual-DC-input (DI) dual-buck inverters (DBIs) is proposed by employing a DI switching cell as the input of traditional DBIs. Three power ports, i.e. a low voltage DC input port, a high voltage DC input port and an AC output port, are provided by the proposed DI-DBIs. A low voltage DC source, whose voltage is lower than the peak amplitude of the AC side voltage, can be directly connected to the DI-DBI. This supplies power to the AC side in single-stage power conversion. When compared with traditional DBI-based two-stage DC/AC power systems, the conversion stages are reduced, and the power rating and power losses of the front-end Boost converter of the DI-DBI are reduced. In addition, five voltage-levels are generated with the help of the two DC input ports, which is a benefit in terms of reducing the voltage stresses and switching losses of switches. The topology derivation method, operation principles, modulation strategy and characteristics of the proposed inverter are analyzed in-depth. Experimental results are provided to verify the effectiveness and feasibility of the proposed DI-DBIs.

Family of Dual-Input Dual-Buck Inverters Based on Dual-Input Switching Cells

Fan Yang,Hongjuan Ge,Jingfan Yang,Runyun Dang,Hongfei Wu 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.4

A family of dual-DC-input (DI) dual-buck inverters (DBIs) is proposed by employing a DI switching cell as the input of traditional DBIs. Three power ports, i.e. a low voltage DC input port, a high voltage DC input port and an AC output port, are provided by the proposed DI-DBIs. A low voltage DC source, whose voltage is lower than the peak amplitude of the AC side voltage, can be directly connected to the DI-DBI. This supplies power to the AC side in single-stage power conversion. When compared with traditional DBI-based two-stage DC/AC power systems, the conversion stages are reduced, and the power rating and power losses of the front-end Boost converter of the DI-DBI are reduced. In addition, five voltage-levels are generated with the help of the two DC input ports, which is a benefit in terms of reducing the voltage stresses and switching losses of switches. The topology derivation method, operation principles, modulation strategy and characteristics of the proposed inverter are analyzed in-depth. Experimental results are provided to verify the effectiveness and feasibility of the proposed DI-DBIs.

Risk assessment of aviation DC series arc based on reconstructed CBAM‑CNN

Haoqi Yang,Cong Gao,Hongjuan Ge,Yiqin Sang,Yongshuai Wang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.5

The hazards of sustained arc and un-sustained arc are different. However, during the stage of arc development, there is a lack of effective methods to identify them, which is not conducive to the timely accurate assessment of arc risk. Therefore, this paper proposes a risk assessment method for aviation DC series arc based on a reconstructed CBAM-CNN. First, in the process of generating the feature set, a feature evaluation function is defined to screen the features. Then the existing convolution block attention module (CBAM) is improved by adding a reshaped layer and redefining spatial attention, which results in the reconstructed CBAM-CNN. Finally, the reconstructed CBAM-CNN takes the feature set as its input and output arc risk assessment results on the basis of enhancing the attention of important features. The validity of the reconstructed CBAM-CNN method is verified on an aviation DC arc generation platform. It is found that the proposed method has a higher training efficiency and evaluation accuracy than the CNN method and CBAM-CNN method. In addition, the reconstructed CBAM-CNN involves fewer parameters to be measured, which can reduce its dependence on computing resources.

Improved SVPWM modulation method for three‑phase dual‑input dual‑buck inverters

Yongshuai Wang,Hongjuan Ge,Hang Yin,Bingjie Wu,Fan Yang 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.5

The traditional modulation method for three-phase dual-input dual-buck inverters is level-shifted sine pulse width modulation. The disadvantage of this method is that the dc voltage utilization ratio is low and the software fault tolerance is difficult to realize. To solve these problems, an improved SVPWM suitable for this inverter is proposed in this paper. By analyzing the switch modes and bridge arm midpoint level of this inverter, 27 voltage vectors are obtained. According to the obtained long vector cluster, medium vector cluster, and short vector cluster, six modulation sectors are obtained, and each modulation sector has four modulation regions. When the voltage of the inverter low-voltage dc source changes, the associated vector changes as well. How the modulation region changes when the associated vector changes is analyzed. The action time of each vector in each modulation region is deduced. In addition, the action order of each vector involved in vector synthesis is optimized. A 2 kW prototype was built to carry out experimental research. Experimental results show that this modulation method improves the dc voltage utilization ratio, reduces the loss, and improves the efficiency of the inverter.

A Case Study of the Rapid and Long Runout Landslide at Hong′ao Waste Disposal Site in Shenzhen, China

Kai Wang,Shaojie Zhang,Fangqiang Wei,Hongjuan Yang 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.3

A disastrous landslide occurred at the Hong’ao Waste Disposal Site in Shenzhen, China on December 20, 2015, involving a volume of 2.7 × 106 m3 of municipal solid waste (MSW) that travelled a distance of 700 to 800 m, covering an area of 3.8 × 105 m2 and caused 90 casualties. The geomorphological and geological characteristics of the waste disposal site were carefully examined and the landslide was classified as an extremely rapid flowslide. The major feature of the waste site was the basin-like structure with the bottom composed of low-permeable granite bedrock. Therefore, surface runoff could easily accumulate in the MSW due to the lack of drainage system, resulting in an increasing groundwater level. Laboratory tests, including physical characterization, Consolidation Isotropic Undrained (CIU) test and direct shear test were conducted to characterize the material properties of the MSW. Physical characterization indicated the MSW belongs to sandy silt, CIU tests indicated that static liquefaction was conducive to high-speed sliding. The direct shear test data were used to carry out numerical analysis of slope stability, in which the continuous rise in the groundwater level was taken into account. Numerical simulation showed that the pore water pressure induced by underground water seepage and gradual loading from the upper MSW placement aggravate the failure. Consequently, the main reason of the landslide could be concluded as follows: 1) the perched groundwater level due to a large upstream catchment area and the lack of drainage system; 2) the excess pore water pressure induced by static liquefaction played a significant role in its mobility.

Pollen record of the mid- to late-Holocene centennial climate change on the East coast of South Korea and its influential factors

Song, Bing,Yi, Sangheon,Jia, Hongjuan,Nahm, Wook-Hyun,Kim, Jin-Cheul,Lim, Jaesoo,Lee, Jin-Young,Sha, Longbin,Mao, Limi,Yang, Zhongyong,Nakanishi, Toshimichi,Hong, Wan,Li, Zhen Elsevier 2018 Journal of Asian earth sciences Vol.151 No.-

<P><B>Abstract</B></P> <P>To understand historical climate change in western Pacific coastal areas, a sediment core (SOJ-2) from the stable sedimentary environment of the Songjiho Lagoon on the east coast of South Korea was obtained for centennial-resolution palynological analysis. The ages of the SOJ-2 core is well controlled by carbon 14 dating with high-resolution accelerator mass spectrometry (AMS), and the results indicated a general warm to cold climate trend from the mid-Holocene to the present, which can be divided into two different stages: a warmer stage between 6842 and 1297 cal yr BP and a colder stage from 1297 cal yr BP to the present, with fluctuations during these stages. The climate was wetter from 6842 to 6227 cal yr BP and 4520 to 1297 cal yr BP and was drier from 6227 to 4520 cal yr BP. The climate changed to cold and dry during the period from 1297–425 cal yr BP. The impact of human activity on the climate began at approximately 1297 cal yr BP and became pronounced starting in 425 cal yr BP. The general cooling trend may represent a response to decreasing solar insolation; however, the relative dryness or wetness of the climate may have been co-determined by westerlies and the East Asian summer monsoon (EASM). The climate had a teleconnection with the North Atlantic region, resulting from changes in solar activity. Nevertheless, EI Niño–Southern Oscillation (ENSO) activity played an important role in impacting the EASM changes in western Pacific coastal areas.</P> <P><B>Highlights</B></P> <P> <UL> <LI> There is a centennial resolution climate record from 6842 cal yr BP to present. </LI> <LI> The general cooling trend was probably triggered by decreasing solar insolation. </LI> <LI> The precipitation was co-determined by westerlies and the East Asian Summer Monsoon. </LI> <LI> The ENSO activity may be an important factor for East Asian Summer Monsoon change. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Characterization and catalytic application of MnCl2 modified HZSM-5 zeolites in synthesis of aromatics from syngas via dimethyl ether

Qingde Zhang,Yisheng Tan,Caihong Yang,Hongjuan Xie 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.3

The conversion of syngas to aromatics via dimethyl ether was investigated over MnCl2 modified HZSM-5zeolites. The results demonstrated that 2%MnCl2 modified HZSM-5 (SiO2/Al2O3 = 38) exhibited higher pxylene selectivity than other catalysts and further decreased 1,2,4,5-tetramethylbenzene selectivity. The CO conversion was obviously increased after 5%MnCl2 modification to HZSM-5. The catalysts were characterized by XRD, BET, XPS, FT-IR, NH3-TPD, SEM, element analysis and O2-TPO. The loading amount of MnCl2 affected the adsorption and reaction of DME molecules on zeolites. Appropriate amount of MnCl2 introduction could adjust the acidity and pore volume of HZSM-5 to increase p-xylene selectivity and CO conversion.

The F-box Protein KIB1 Mediates Brassinosteroid-Induced Inactivation and Degradation of GSK3-like Kinases in <i>Arabidopsis</i>

Zhu, Jia-Ying,Li, Yuyao,Cao, Dong-Mei,Yang, Hongjuan,Oh, Eunkyoo,Bi, Yang,Zhu, Shengwei,Wang, Zhi-Yong Elsevier 2017 Molecular cell Vol.66 No.5

<P><B>Summary</B></P> <P>The glycogen synthase kinase-3 (GSK3) family kinases are central cellular regulators highly conserved in all eukaryotes. In <I>Arabidopsis</I>, the GSK3-like kinase BIN2 phosphorylates a range of proteins to control broad developmental processes, and BIN2 is degraded through unknown mechanism upon receptor kinase-mediated brassinosteroid (BR) signaling. Here we identify KIB1 as an F-box E3 ubiquitin ligase that promotes the degradation of BIN2 while blocking its substrate access. Loss-of-function mutations of KIB1 and its homologs abolished BR-induced BIN2 degradation and caused severe BR-insensitive phenotypes. KIB1 directly interacted with BIN2 in a BR-dependent manner and promoted BIN2 ubiquitination in vitro. Expression of an F-box-truncated KIB1 caused BIN2 accumulation but dephosphorylation of its substrate BZR1 and activation of BR responses because KIB1 blocked BIN2 binding to BZR1. Our study demonstrates that KIB1 plays an essential role in BR signaling by inhibiting BIN2 through dual mechanisms of blocking substrate access and promoting degradation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> KIB1 is an essential positive regulator in brassinosteroid signaling </LI> <LI> KIB1 mediates BR-induced ubiquitination and degradation of GSK3 kinase BIN2 </LI> <LI> KIB1 binding to BIN2 prevents BIN2-substrate interaction and promotes BIN2 degradation </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</P>

Analysis of the effect of Rhodopseudomonas palustris on the lead exposure rat model using 1H-NMR-based metabolomics of urine and plasma

Chai Shutong,Zheng Ziyun,Liu Yani,Liang Yanhui,Yang Hong,Chen Jie,Bai Hongjuan,Yang Guan-e 대한독성 유전단백체 학회 2023 Molecular & cellular toxicology Vol.19 No.2

Background Rhodopseudomonas palustris had the eff ect of adsorbing and removing lead ions. Metabolomics is a comprehensive analysis based on several metabolites or biomarkers. Objective The paper aimed to investigate the restorative eff ect and the potential mechanisms of R. palustris in rats with the lead exposure model using 1 H-NMR metabolomics. Results Nine endogenous metabolites from rat plasma and 13 endogenous metabolites from rat urine were identifi ed as potential biomarkers of the symptoms of lead poisoning. The changes of metabolites levels in the plasma included lower levels of valine, acetoacetate, and N-acetyl-glycoprotein and a higher concentration of lactate, acetate, creatine, threonine, glutamine, and asparagine in model group compared with control group. Furthermore, increased citrate, succinate, dimethylamine, pyruvate, acetoacetate, α -oxoglutarate and asparagine, accompanied by decreased LDL/VLDL, taurine, creatinine, glucose and hippurate levels were observed in the model group compared with the control group in the urine. Biochemical parameters and histopathology examination dovetailed well with the metabolomics data. Treatment with R. palustris at a certain degree returned the levels of these metabolites to normal levels. Plasma and urine metabolomic analysis showed changes associated with energy metabolism, amino acids and fatty acid metabolism of lead exposure rats. Conclusion The eff ects of removing lead ions of R. palustris in rats with lead exposure were confi rmed. This research demonstrated that 1 H-NMR-based metabolomics was a promising tool to identify potential biomarkers and unravel protective eff ect mechanisms of R. palustris in lead poisoning rats.

Hepatitis B Virus Core Protein Mediates the Upregulation of C5α Receptor 1 via NF-κB Pathway to Facilitate the Growth and Migration of Hepatoma Cells

Fanyun Kong,Yukai Tao,Dongchen Yuan,Ning Zhang,Qi Li,Tong Yu,Xiaoying Yang,Delong Kong,Xiaohui Ding,Xiangye Liu,Hongjuan You,Kuiyang Zheng,Renxian Tang 대한암학회 2021 Cancer Research and Treatment Vol.53 No.2

Purpose C5α receptor 1 (C5ΑR1) is associated with the development of various human cancers. However, whether it is involved in the development of hepatitis B virus (HBV)–related hepatocellular carcinoma (HCC) is poorly understood. We explored the expression, biological role, and associated mechanisms of C5AR1 in HBV-related hepatoma cells. Materials and Methods The expression of C5ΑR1 mediated by HBV and HBV core protein (HBc) was detected in hepatoma cells. The function of nuclear factor кB (NF-κB) pathway in HBc-induced C5AR1 expression was assessed. The roles of C5ΑR1 in the activation of intracellular signal pathways, the upregulation of inflammatory cytokines, and the growth and migration of hepatoma cells mediated by HBc, were investigated. The effect of C5α in the development of HCC mediated by C5AR1 was also measured. Results C5ΑR1 expression was increased in HBV-positive hepatoma cells. Dependent on HBc, HBV enhanced the expression of C5ΑR1 at the mRNA and protein levels. Besides, HBc could promote C5ΑR1 expression via the NF-κB pathway. Based on the C5ΑR1, HBc facilitated the activation of JNK and ERK pathways and the expression and secretion of interleukin-6 in hepatoma cells. Furthermore, C5ΑR1 was responsible for enhancing the growth and migration of hepatoma cells mediated by HBc. Except these, C5α could promote the malignant development of HBc-positive HCC via C5AR1. Conclusion We provide new insight into the mechanisms of hepatocarcinogenesis mediated by HBc. C5ΑR1 has a significant role in the functional abnormality of hepatoma cells mediated by HBc, and might be utilized as a potential therapeutic target for HBV-related HCC.