Decentralized control strategy for storage systems in islanded microgrids

Liwei Zhang,Lei Dai,Changming Zhao 전력전자학회 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.12

This paper presents a decentralized control strategy for the distributed storage (DS) systems of the islanded microgrid composed of distributed generations (DGs) and DSs. Each of the DSs consists of a bidirectional DC-DC converter cascaded with a three-phase inverter. Control strategies for DSs and DGs are based on droop control. The line frequency of the point of common coupling (PCC) is an agent to regulate the active power of the DS. Due to the power mismatch among the supplies and load demands of DGs, the frequency controller of the DS generates its active power reference. In addition, the frequency deviation caused by droop control can be reduced. Reactive load power is almost equally shared by all of the constituent units. Therefore, the DS works by charging or discharging the energy storage devices. Simulation and experimental results are provided to verify the effectiveness of the proposed control strategy.

Research on Improved Firefly Optimization Algorithm Based on Cooperative for Clustering

Zhao Hongwei,Tian Liwei,Wang Dongzheng 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.3

This paper built a optimization model and proposed an improved firefly optimization algorithm called CFA, which is based on firefly Cooperative. The main idea of CFA is to extend the single population FA to the interacting multi-swarms by cooperative Models. In this work, firstly, CFA algorithm is used for optimizing six widely-used benchmark functions and the comparative results produced by, firefly optimization algorithm(FA) are studied. Secondly, CFA algorithm used in data mining, clustering analysis on several typical data sets. The performance of typical data clustering results showed that the biological heuristic algorithm based on clustering analysis algorithm with the existing success of FA compared to faster convergence, and the clustering of higher quality.

Cooperative Approaches to Bacterial Foraging Algorithm for Clustering

Zhao Hongwei,Tian Liwei 보안공학연구지원센터 2015 International Journal of Database Theory and Appli Vol.8 No.4

Bacterial Foraging Optimization (BFO) is a novel optimization algorithm based on the social foraging behavior of E. coli bacteria, but it is difficult to optimize to get a high precision due to the randomness of the bacterial behavior, which belongs to intelligence algorithm. This paper presents an extended BFO algorithm, namely the Cooperative Bacterial Foraging Optimization (CBFO), which significantly improves the original BFO in solving clustering problems. A novel clustering method based on the CBFO could be used for solving clustering problems. In this work, firstly, The efficiency and performance of the CBFO algorithm was evaluated using six widely-used benchmark functions, coming up with comparative results produced by BFO, then Particle Swarm Optimization (PSO) is studied. Secondly, the algorithm with CBFO algorithms is used for data clustering on several benchmark data sets. The performance of the algorithm based on CBFO is compared with BFO algorithms on clustering problem. The simulation results show that the proposed CBFO outperforms the other three algorithms in terms of accuracy, robustness and convergence speed.

Simulation of in-situ preheating of ni-based multi-layer and multi-pass coatings on H13 steel

Honggang Yin,Jinhua LI,Liwei Zhao,Fangping Yao 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9

COMSOL was used to simulate the temperature field of the preheating and nonpreheating processes of the laser cladding multi-layer and multi-pass coating, and experimental verification was carried out. The results show that the temperature gradient value of the coating at the Z-axis is much larger than the value at the X and Y-axis, respectively. It indicates that the coating is sensitive to cracks at the Z-axis. After preheating, the quality of the coating is improved, and the results of the geometric morphology in experiments are basically consistent with the results of simulation. With increase in coating temperature, the cladding efficiency increased. The difference of temperature between the first and second layer was significantly reduced. The temperature gradient value at the Z-axis decreased. The coating grain structure presents as refined and well-distributed. The temperature gradient size in each layer decreased with the number of coatings increasing.

Panax ginseng total protein promotes proliferation and secretion of collagen in NIH/3T3 cells by activating extracellular signal-related kinase pathway

Chen, Xuenan,Wang, Manying,Xu, Xiaohao,Liu, Jianzeng,Mei, Bing,Fu, Pingping,Zhao, Daqing,Sun, Liwei The Korean Society of Ginseng 2017 Journal of Ginseng Research Vol.41 No.3

Background: Recently, protein from ginseng was studied and used for the treatment of several kinds of diseases. However, the effect of ginseng total protein (GTP) on proliferation and wound healing in fibroblast cells remains unclear. Methods: In this study, cell viability was analyzed using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. Cell cycle distribution was analyzed by flow cytometer. The levels of transforming growth factor ${\beta}1$, vascular endothelial growth factor, and collagens were analyzed by enzyme-linked immunosorbent assay and immunofluorescence staining. The expressions of cyclin A, phosphorylation of extracellular signal-related kinase (p-ERK1/2), and ERK1/2 were analyzed by Western blotting. Results: Our results showed that GTP promoted cell proliferation and increased the percentage of cells in S phase through the upregulation of cyclin A in NIH/3T3 cells. We also found that GTP induced the secretion of type I collagen, and promoted the expression of other factors that regulate the synthesis of collagen such as transforming growth factor ${\beta}1$ and vascular endothelial growth factor. In addition, the phosphorylation of ERK1/2 at Thr202/Tyr204 was also increased by GTP. Conclusion: Our studies suggest that GTP promoted proliferation and secretion of collagen in NIH/3T3 cells by activating the ERK signal pathway, which shed light on a potential function of GTP in promoting wound healing.

Ginsenosides repair UVB-induced skin barrier damage in BALB/c hairless mice and HaCaT keratinocytes

Zhenzhuo Li,Rui Jiang,Manying Wang,Lu Zhai,Jianzeng Liu,Xiaohao Xu,Liwei Sun,Daqing Zhao 고려인삼학회 2022 Journal of Ginseng Research Vol.46 No.1

Background: Ginsenosides (GS) have potential value as cosmetic additives for prevention of skin photoaging. However, their protective mechanisms against skin barrier damage and their active monomeric constituents are unknown. Methods: GS monomer types and their relative proportions were identified. A UVB-irradiated BALB/c hairless mouse model was used to assess protective effects of GS components on skin epidermal thickness and transepidermal water loss (TEWL). Skin barrier function, reflected by filaggrin (FLG), involucrin (IVL), claudin-1 (Cldn-1), and aquaporin 3 (AQP3) levels and MAPK phosphorylation patterns, were analyzed in UVB-irradiated hairless mice or HaCaT cells. Results: Total GS monomeric content detected by UPLC was 85.45% and was largely attributed to 17 main monomers that included Re (16.73%), Rd (13.36%), and Rg1 (13.38%). In hairless mice, GS ameliorated UVB-induced epidermal barrier dysfunction manifesting as increased epidermal thickness, increased TEWL, and decreased stratum corneum water content without weight change. Furthermore, GS treatment of UVB-irradiated mice restored protein expression levels and epidermal tissue distributions of FLG, IVL, Cldn-1, and AQP3, with consistent mRNA and protein expression results obtained in UVB-irradiated HaCaT cells (except for unchanging Cldn-1 expression). Mechanistically, GS inhibited JNK, p38, and ERK phosphorylation in UVB-irradiated HaCaT cells, with a mixture of Rg2, Rg3, Rk3, F2, Rd, and Rb3 providing the same protective MAPK pathway inhibition-associated upregulation of IVL and AQP3 expression as provided by intact GS treatment. Conclusion: GS protection against UVB-irradiated skin barrier damage depends on activities of six ginsenoside monomeric constituents that inhibit the MAPK signaling pathway.

Panax ginseng total protein promotes proliferation and secretion of collagen in NIH/3T3 cells by activating extracellular signal-related kinase pathway

Xuenan Chen,Manying Wang,Xiaohao Xu,Jianzeng Liu,Bing Mei,Pingping Fu,Da-Qing Zhao,Liwei Sun 고려인삼학회 2017 Journal of Ginseng Research Vol.41 No.3

Background: Recently, protein from ginseng was studied and used for the treatment of several kinds of diseases. However, the effect of ginseng total protein (GTP) on proliferation and wound healing in fibroblast cells remains unclear. Methods: In this study, cell viability was analyzed using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide] assay. Cell cycle distribution was analyzed by flow cytometer. The levels of transforming growth factor b1, vascular endothelial growth factor, and collagens were analyzed by enzyme-linked immunosorbent assay and immunofluorescence staining. The expressions of cyclin A, phosphorylation of extracellular signal-related kinase (p-ERK1/2), and ERK1/2 were analyzed byWestern blotting. Results: Our results showed that GTP promoted cell proliferation and increased the percentage of cells in S phase through the upregulation of cyclin A in NIH/3T3 cells. We also found that GTP induced the secretion of type I collagen, and promoted the expression of other factors that regulate the synthesis of collagen such as transforming growth factor b1 and vascular endothelial growth factor. In addition, the phosphorylation of ERK1/2 at Thr202/Tyr204 was also increased by GTP. Conclusion: Our studies suggest that GTP promoted proliferation and secretion of collagen in NIH/3T3 cells by activating the ERK signal pathway, which shed light on a potential function of GTP in promoting wound healing.

Phenolic acids in Panax ginseng inhibit melanin production through bidirectional regulation of melanin synthase transcription via different signaling pathways

Jianzeng Liu,Xiaohao Xu,Jingyuan Zhou,Guang Sun,Zhenzhuo Li,Lu Zhai,Jing Wang,Rui Ma,Daqing Zhao,Rui Jiang,Liwei Sun 고려인삼학회 2023 Journal of Ginseng Research Vol.47 No.6

Background: Our previous investigation indicated that the preparation of Panax ginseng Meyer(P. ginseng) inhibited melanogenesis. It comprised salicylic acid (SA), protocatechuic acid (PA), p-coumaricacid (p-CA), vanillic acid (VA), and caffeic acid (CA). In this investigation, the regulatory effects ofP. ginseng phenolic acid monomers on melanin production were assessed. Methods: In vitro and in vivo impact of phenolic acid monomers were assessed. Results: SA, PA, p-CA and VA inhibited tyrosinase (TYR) to reduce melanin production, whereas CA hadthe opposite effects. SA, PA, p-CA and VA significantly downregulated the melanocortin 1 receptor(MC1R), cycle AMP (cAMP), protein kinase A (PKA), cycle AMP-response element-binding protein (CREB),microphthalmia-associated transcription factor (MITF) pathway, reducing mRNA and protein levels ofTYR, tyrosinase-related protein 1 (TYRP1), and TYRP2. Moreover, CA treatment enhanced the cAMP, PKA,and CREB pathways to promote MITF mRNA level and phosphorylation. It also alleviated MITF proteinlevel in a-MSH-stimulated B16F10 cells, comparable to untreated B16F10, increasing the expression ofphosphorylation glycogen synthase kinase 3b (p-GSK3b), b-catenin, p-ERK/ERK, and p-p38/p38. Furthermore, the GSK3b inhibitor promoted p-GSK3b and p-MITF expression, as observed in CA-treatedcells. Moreover, p38 and ERK inhibitors inhibited CA-stimulated p-p38/p38, p-ERK/ERK, and p-MITFincrease, which had negative binding energies with MC1R, as depicted by molecular docking. Conclusion: P. ginseng roots' phenolic acid monomers can safely inhibit melanin production by bidirectionallyregulating melanin synthase transcription. Furthermore, they reduced MITF expression viaMC1R/cAMP/PKA signaling pathway and enhanced MITF post-translational modification via Wnt/mitogen-activated protein kinase signaling pathway.

Major ginsenosides from Panax ginseng promote aerobic cellular respiration and SIRT1-mediated mitochondrial biosynthesis in cardiomyocytes and neurons

Huang, Qingxia,Lou, Tingting,Lu, Jing,Wang, Manying,Chen, Xuenan,Xue, Linyuan,Tang, Xiaolei,Qi, Wenxiu,Zhang, Zepeng,Su, Hang,Jin, Wenqi,Jing, Chenxu,Zhao, Daqing,Sun, Liwei,Li, Xiangyan The Korean Society of Ginseng 2022 Journal of Ginseng Research Vol.46 No.6

Background: Aerobic cellular respiration provides chemical energy, adenosine triphosphate (ATP), to maintain multiple cellular functions. Sirtuin 1 (SIRT1) can deacetylate peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) to promote mitochondrial biosynthesis. Targeting energy metabolism is a potential strategy for the prevention and treatment of various diseases, such as cardiac and neurological disorders. Ginsenosides, one of the major bioactive constituents of Panax ginseng, have been extensively used due to their diverse beneficial effects on healthy subjects and patients with different diseases. However, the underlying molecular mechanisms of total ginsenosides (GS) on energy metabolism remain unclear. Methods: In this study, oxygen consumption rate, ATP production, mitochondrial biosynthesis, glucose metabolism, and SIRT1-PGC-1α pathways in untreated and GS-treated different cells, fly, and mouse models were investigated. Results: GS pretreatment enhanced mitochondrial respiration capacity and ATP production in aerobic respiration-dominated cardiomyocytes and neurons, and promoted tricarboxylic acid metabolism in cardiomyocytes. Moreover, GS clearly enhanced NAD⁺-dependent SIRT1 activation to increase mitochondrial biosynthesis in cardiomyocytes and neurons, which was completely abrogated by nicotinamide. Importantly, ginsenoside monomers, such as Rg1, Re, Rf, Rb1, Rc, Rh1, Rb2, and Rb3, were found to activate SIRT1 and promote energy metabolism. Conclusion: This study may provide new insights into the extensive application of ginseng for cardiac and neurological protection in healthy subjects and patients.

Numerical calculation and optimization designs in engine cooling water pump

Li Wei,Wang Chuan,Shi Weidong,Zhao Xiaofan,Yang Yongfei,Pei Bing 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.5

The cavitation damage in the Engine cooling water pump (ECWP) is the key factor that shortens the lifespan of automobile cooling systems, and causes vibration and noise. To improve cavitation performance and external characteristics of ECWP, three optimized models were designed on the basis of WP7 diesel ECWP. The whole flow fields in three models and the prototype pump were numerically simulated, employing the time averaged Navier-Stokes equation, the standard k-ε turbulent model and Zwart-Gerber-Belamri multiphase flow model by ANSYS-CFX software. Pressure distribution, turbulent kinetic energy distribution, bubble volume fraction distribution, external characteristics and cavitation performance of the prototype pump and optimized models were compared and analyzed. The results show that the external characteristics and cavitation performance of the optimized models are significantly better than that in the prototype pump. Through decreasing the inlet blade angle and wrap angle, extending the blade to inlets and extending a certain inclination in the blade, shock loss in blade inlet was reduced and so, the performance of pump will be improved. The flow condition at blade inlet will also be improved greatly, which in turn improves cavitation performance. When reducing the quantity of blades, the excretion coefficient will drop, flow area of blade inlet becomes bigger, but head has a little drop. And the pump optimized by reducing the quantity of blades has the optimal cavitation performance among three optimized models. With the decrease of impeller diameter, the absolute pressure in the critical cavitation point becomes bigger, the inlet bubble volume fraction at the same absolute pressure increases while cavitation performance gets worse. The obtained numerical results were compared with the experimental ones, and the outcome showed the same tendency between the two along with acceptable error.