Parameters optimization design for LCL-type STATCOMs under complex power grid

Wang, Xiangyu,Wang, Minglei,Wang, Liguo,Fu, Guangjie,Qiao, Jinxin The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.2

LCL filter parameters and control parameters are interdependent and inter-restricted. They can all affect the stability of a static synchronous compensator (STATCOM) under the effects of a complex power grid such as harmonic grid voltage and grid impedance variation. An advanced parameters optimization method integrated with LCL filter and control strategy is proposed. At first, the ABC-Pareto algorithm (Pareto multi-objective optimization of an artificial bee colony algorithm) is used to reasonably choose the LCL filter parameters. Under the premise of using capacitor current feedback active damping control and grid voltage feedforward control, the mathematical models of the STATCOM are derived. The constraints of control performances on the control parameters are obtained. According to these constraints, it is possible to construct a satisfactory 3D space. The control parameters can be chosen reasonably by finding the optimized space when the power grid is changed. Simulation and experimental results show the effectiveness and superiority of the proposed method.

Optimization of Ultrasonic-assisted Extraction of Flavonoid from Portulaca oleracea L. by Response Surface Methodology and Chemical Composition Analysis

Wang, Chenxi,Li, Yuping,Yao, Lihua,Wu, Guangjie,Chang, Jun,Shu, Chengchuang,Chen, Meiqin 한국응용생명화학회 2014 Applied Biological Chemistry (Appl Biol Chem) Vol.57 No.5

Optimization of ultrasonic extraction of Portulaca oleracea L. flavonoids (POF) was investigated using single-factor experimentation combined with response surface methodology. The optimal conditions for the highest yield (16.25 mg RE/g DW) of POF was 39.01% ethanol, $55.25^{\circ}C$ extraction temperature, 15 min extraction time, and 23.92 (v/m) liquid-to-solid ratio. The crude extract of POF was purified on the polyamide resin. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a yellow tetrazole assays of the flavonoids were evaluated, which suggested the concentrations of the flavonoids (0-1 mg/mL) and quercetin (0-1 mg/mL). Quercetin was identified in the extract by comparing relative retention time of the reference standard.

The model analysis of the evolutionary route of rural financial cooperation in China

Wang Wei,Tong Guangji,Tan Xiaojing 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

Although central government has implemented a series of reforms, development and promotion in the rural financial field since rural reform, under a completely isolated state, it could only cause "performance noncooperation" between the rural finance support system to the rural support policy. This paper has set up an angle balanced model, and the analysis on the model indicated that the entire process growing gradually from nothing of occurrence, development and maturation of the financial coooperation went with the harmonious advantage which the government offering harmoniy service obtained from the financial service offered by its own. Therefore, the reasonable system arrangement could reduce the transaction cost which was brought by the resource supply restraint and the development of the finnancial market, reduce the difference between the individual income and the social efficiency, promote the individual to engage in the coordinative activities ans finally cause the growth of the financial gross.

Detection and Parameter Estimation for Jitterbug Covert Channel Based on Coefficient of Variation

( Hao Wang ),( Guangjie Liu ),( Jiangtao Zhai ),( Yuewei Dai ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.4

Jitterbug is a passive network covert timing channel supplying reliable stealthy transmission. It is also the basic manner of some improved covert timing channels designed for higher undetectability. The existing entropy-based detection scheme based on training sample binning may suffer from model mismatching, which results in detection performance deterioration. In this paper, a new detection method based on the feature of Jitterbug covert channel traffic is proposed. A fixed binning strategy without training samples is used to obtain bins distribution feature. Coefficient of variation (CV) is calculated for several sets of selected bins and the weighted mean is used to calculate the final CV value to distinguish Jitterbug from normal traffic. Furthermore, the timing window parameter of Jitterbug is estimated based on the detected traffic. Experimental results show that the proposed detection method can achieve high detection performance even with interference of network jitter, and the parameter estimation method can provide accurate values after accumulating plenty of detected samples.

Optimization of Ultrasonic-assisted Extraction of Flavonoid from Portulaca oleracea L. by Response Surface Methodology and Chemical Composition Analysis

Chenxi Wang,Yuping Li,Li-Hua Yao,Guangjie Wu,Jun Chang,Chengchuang Shu,Meiqin Chen 한국응용생명화학회 2014 Applied Biological Chemistry (Appl Biol Chem) Vol.57 No.5

Optimization of ultrasonic extraction of Portulacaoleracea L. flavonoids (POF) was investigated using single-factorexperimentation combined with response surface methodology. The optimal conditions for the highest yield (16.25 mg RE/g DW)of POF was 39.01% ethanol, 55.25oC extraction temperature, 15min extraction time, and 23.92 (v/m) liquid-to-solid ratio. Thecrude extract of POF was purified on the polyamide resin. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a yellowtetrazole assays of the flavonoids were evaluated, which suggestedthe concentrations of the flavonoids (0-1 mg/mL) and quercetin(0-1 mg/mL). Quercetin was identified in the extract by comparingrelative retention time of the reference standard.

Genome‑wide identification and expression analysis of the StSWEET family genes in potato (Solanum tuberosum L.)

Ming Li,Haijuan Xie,Miaomiao He,Wang Su,Yongzhi Yang,Jian Wang,Guangji Ye,Yun Zhou 한국유전학회 2020 Genes & Genomics Vol.42 No.2

Background The sugar will eventually be exported transporter (SWEET) family is a novel type of membrane-embedded sugar transporter that contains seven transmembrane helices with two MtN3/saliva domains. The SWEET family plays crucial roles in multiple processes, including carbohydrate transportation, development, environmental adaptability and host–pathogen interactions. Although SWEET genes, especially those involved in response to biotic stresses, have been extensively characterized in many plants, they have not yet been studied in potato. Objective The identification of StSWEET genes provides important candidates for further functional analysis and lays the foundation for the production of good quality and high yield potatoes through molecular breeding. Methods In this study, StSWEET genes were identified using a genome-wide search method. A comprehensive analysis of StSWEET family through bioinformatics methods, such as phylogenetic tree, gene structure and promoter prediction analysis. The expression profiles of StSWEET genes in different potato tissues and under P. infestans attack and sugar stress were studied using quantitative real-time polymerase chain reaction (qRT-PCR). Results Phylogenetic analysis classified 33 StSWEET genes into four groups containing 12, 5, 12 and 4 genes. Furthermore, the gene structures and conserved motifs found that the StSWEET genes are very conservative during evolution. The chromosomal localization pattern showed that the distribution and density of the StSWEETs on 10 potato chromosomes were uneven and basically clustered. Predictive promoter analysis indicated that StSWEET proteins are associated with cell growth, development, secondary metabolism, and response to biotic and abiotic stresses. Finally, the expression patterns of the StSWEET genes in different tissues and the induction of P. infestans and the process of the sugar stress were investigated to obtain the tissue-specific and stress-responsive candidates. Conclusion This study systematically identifies the SWEET gene family in potato at the genome-wide level, providing important candidates for further functional analysis and contributing to a better understanding of the molecular basis of development and tolerance in potato.

Ginsenoside Rb1 exerts neuroprotective effects through regulation of Lactobacillus helveticus abundance and GABA_A receptor expression

Chen, Huimin,Shen, Jiajia,Li, Haofeng,Zheng, Xiao,Kang, Dian,Xu, Yangfan,Chen, Chong,Guo, Huimin,Xie, Lin,Wang, Guangji,Liang, Yan The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.1

Background: Ginsenoside Rb1 (Rb1), one of the most abundant protopanaxadiol-type ginsenosides, exerts excellent neuroprotective effects even though it has low intracephalic exposure. Purpose: The present study aimed to elucidate the apparent contradiction between the pharmacokinetics and pharmacodynamics of Rb1 by studying the mechanisms underlying neuroprotective effects of Rb1 based on regulation of microflora. Methods: A pseudo germ-free (PGF) rat model was established, and neuroprotective effects of Rb1 were compared between conventional and PGF rats. The relative abundances of common probiotics were quantified to reveal the authentic probiotics that dominate in the neuroprotection of Rb1. The expressions of the gamma-aminobutyric acid (GABA) receptors, including GABAA receptors (α2, β2, and γ2) and GABAB receptors (1b and 2), in the normal, ischemia/reperfusion (I/R), and I/R+Rb1 rat hippocampus and striatum were assessed to reveal the neuroprotective mechanism of Rb1. Results: The results showed that microbiota plays a key role in neuroprotection of Rb1. The relative abundance of Lactobacillus helveticus (Lac.H) increased 15.26 fold after pretreatment with Rb1. I/R surgery induced effects on infarct size, neurological deficit score, and proinflammatory cytokines (IL-1β, IL-6, and TNF-α) were prevented by colonizing the rat gastrointestinal tract with Lac.H (1 × 10⁹ CFU) by gavage 15 d before I/R surgery. Both Rb1 and Lac.H upregulated expression of GABA receptors in I/R rats. Coadministration of a GABA_A receptor antagonist significantly attenuated neuroprotective effects of Rb1 and Lac.H. Conclusion: In sum, Rb1 exerts neuroprotective effects by regulating Lac.H and GABA receptors rather than through direct distribution to the target sites.

Ginsenoside Rb1 exerts neuroprotective effects through regulation of Lactobacillus helveticus abundance and GABAA receptor expression

Huimin Chen,Jiajia Shen,Haofeng Li,Xiao Zheng,Dian Kang,Yangfan Xu,Chong Chen,Huimin Guo,Lin Xie,Guangji Wang,Yan Liang 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.1

Background: Ginsenoside Rb1 (Rb1), one of the most abundant protopanaxadiol-type ginsenosides, exertsexcellent neuroprotective effects even though it has low intracephalic exposure. Purpose: The present study aimed to elucidate the apparent contradiction between the pharmacokineticsand pharmacodynamics of Rb1 by studying the mechanisms underlying neuroprotective effects ofRb1 based on regulation of microflora. Methods: A pseudo germ-free (PGF) rat model was established, and neuroprotective effects of Rb1 werecompared between conventional and PGF rats. The relative abundances of common probiotics werequantified to reveal the authentic probiotics that dominate in the neuroprotection of Rb1. The expressionsof the gamma-aminobutyric acid (GABA) receptors, including GABAA receptors (a2, b2, and g2) andGABAB receptors (1b and 2), in the normal, ischemia/reperfusion (I/R), and I/RþRb1 rat hippocampus andstriatum were assessed to reveal the neuroprotective mechanism of Rb1. Results: The results showed that microbiota plays a key role in neuroprotection of Rb1. The relativeabundance of Lactobacillus helveticus (Lac.H) increased 15.26 fold after pretreatment with Rb1. I/R surgeryinduced effects on infarct size, neurological deficit score, and proinflammatory cytokines (IL-1b, IL-6, andTNF-a) were prevented by colonizing the rat gastrointestinal tract with Lac.H (1 109 CFU) by gavage 15d before I/R surgery. Both Rb1 and Lac.H upregulated expression of GABA receptors in I/R rats. Coadministrationof a GABAA receptor antagonist significantly attenuated neuroprotective effects of Rb1 and Lac.H. Conclusion: In sum, Rb1 exerts neuroprotective effects by regulating Lac.H and GABA receptors ratherthan through direct distribution to the target sites.

Ginsenoside Rb1 exerts neuroprotective effects through regulation of Lactobacillus helveticus abundance and GABA<SUB>A</SUB> receptor expression

Huimin Chen,Jiajia Shen,Haofeng Li,Xiao Zheng,Dian Kang,Yangfan Xu,Chong Chen,Huimin Guo,Lin Xie,Guangji Wang,Yan Liang 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.1

Background: Ginsenoside Rb1 (Rb1), one of the most abundant protopanaxadiol-type ginsenosides, exerts excellent neuroprotective effects even though it has low intracephalic exposure. Purpose: The present study aimed to elucidate the apparent contradiction between the pharmacokinetics and pharmacodynamics of Rb1 by studying the mechanisms underlying neuroprotective effects of Rb1 based on regulation of microflora. Methods: A pseudo germ-free (PGF) rat model was established, and neuroprotective effects of Rb1 were compared between conventional and PGF rats. The relative abundances of common probiotics were quantified to reveal the authentic probiotics that dominate in the neuroprotection of Rb1. The expressions of the gamma-aminobutyric acid (GABA) receptors, including GABAA receptors (α2, β2, and γ2) and GABAB receptors (1b and 2), in the normal, ischemia/reperfusion (I/R), and I/RþRb1 rat hippocampus and striatum were assessed to reveal the neuroprotective mechanism of Rb1. Results: The results showed that microbiota plays a key role in neuroprotection of Rb1. The relative abundance of Lactobacillus helveticus (Lac.H) increased 15.26 fold after pretreatment with Rb1. I/R surgery induced effects on infarct size, neurological deficit score, and proinflammatory cytokines (IL-1β, IL-6, and TNF-α) were prevented by colonizing the rat gastrointestinal tract with Lac.H (1×10<SUP>9</SUP> CFU) by gavage 15 d before I/R surgery. Both Rb1 and Lac.H upregulated expression of GABA receptors in I/R rats. Coadministration of a GABAA receptor antagonist significantly attenuated neuroprotective effects of Rb1 and Lac.H. Conclusion: In sum, Rb1 exerts neuroprotective effects by regulating Lac.H and GABA receptors rather than through direct distribution to the target sites.