Analysis of Multi-Agent-Based Adaptive Droop-Controlled AC Microgrids with PSCAD: Modeling and Simulation

Li, Zhongwen,Zang, Chuanzhi,Zeng, Peng,Yu, Haibin,Li, Hepeng,Li, Shuhui The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

A microgrid (MG) with integrated renewable energy resources can benefit both utility companies and customers. As a result, they are attracting a great deal of attention. The control of a MG is very important for the stable operation of a MG. The droop-control method is popular since it avoids circulating currents among the converters without using any critical communication between them. Traditional droop control methods have the drawback of an inherent trade-off between power sharing and voltage and frequency regulation. An adaptive droop control method is proposed, which can operate in both the island mode and the grid-connected mode. It can also ensure smooth switching between these two modes. Furthermore, the voltage and frequency of a MG can be restored by using the proposed droop controller. Meanwhile, the active power can be dispatched appropriately in both operating modes based on the capacity or running cost of the Distributed Generators (DGs). The global information (such as the average voltage and output active power of the MG and so on) required by the proposed droop control method to restore the voltage and frequency deviations can be acquired distributedly based on the Multi Agent System (MAS). Simulation studies in PSCAD demonstrate the effectiveness of the proposed control method.

DEMI-LINEAR ANALYSIS I-BASIC PRINCIPLES

Li, Ronglu,Zhong, Shuhui,Li, Linsong Korean Mathematical Society 2009 대한수학회지 Vol.46 No.3

The family of demi-linear mappings between topological vector spaces is a meaningful extension of the family of linear operators. We establish equicontinuity results for demi-linear mappings and develop the usual theory of distributions and the usual duality theory.

Analysis of Multi-Agent-Based Adaptive Droop-Controlled AC Microgrids with PSCAD

Zhongwen Li,Chuanzhi Zang,Peng Zeng,Haibin Yu,Hepeng Li,Shuhui Li 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

A microgrid (MG) with integrated renewable energy resources can benefit both utility companies and customers. As a result, they are attracting a great deal of attention. The control of a MG is very important for the stable operation of a MG. The droop-control method is popular since it avoids circulating currents among the converters without using any critical communication between them. Traditional droop control methods have the drawback of an inherent trade-off between power sharing and voltage and frequency regulation. An adaptive droop control method is proposed, which can operate in both the island mode and the grid-connected mode. It can also ensure smooth switching between these two modes. Furthermore, the voltage and frequency of a MG can be restored by using the proposed droop controller. Meanwhile, the active power can be dispatched appropriately in both operating modes based on the capacity or running cost of the Distributed Generators (DGs). The global information (such as the average voltage and output active power of the MG and so on) required by the proposed droop control method to restore the voltage and frequency deviations can be acquired distributedly based on the Multi Agent System (MAS). Simulation studies in PSCAD demonstrate the effectiveness of the proposed control method.

Demi-linear analysis I-basic principles

Ronglu Li,Shuhui Zhong,Linsong Li 대한수학회 2009 대한수학회지 Vol.46 No.3

The family of demi-linear mappings between topological vector spaces is a meaningful extension of the family of linear operators. We establish equicontinuity results for demi-linear mappings and develop the usual theory of distributions and the usual duality theory. The family of demi-linear mappings between topological vector spaces is a meaningful extension of the family of linear operators. We establish equicontinuity results for demi-linear mappings and develop the usual theory of distributions and the usual duality theory.

Memory characteristics and tunneling mechanism of Pt nano-crystals embedded in HfAlOx films for nonvolatile flash memory devices

Guangdong Zhou,BoWu,Zhiling Li,Zhijun Xiao,Shuhui Li,Ping Li 한국물리학회 2015 Current Applied Physics Vol.15 No.3

A non-volatile flash memory device based on metal oxide semiconductor (MOS) capacitor structure hasbeen fabricated using platinum nano-crystals(PteNCs) as storage units embedded in HfAlOx high-ktunneling layers. Its memory characteristics and tunneling mechanism are characterized by capacitanceevoltage(CeV) and flat-band voltage-time(ΔVFB-T) measurements. A 6.5 V flat-band voltage(memory window) corresponding to the stored charge density of 2.29 × 1013 cm-2 and about 88% storedelectron reserved after apply ±8 V program or erase voltage for 105 s at high frequency of 1 MHz wasdemonstrated. Investigation of leakage currentevoltage(JeV) indicated that defects-enhanced Pool-Frenkel tunneling plays an important role in the tunneling mechanism for the storage charges. Hence,the PteNCs and HfAlOx based MOS structure has a promising application in non-volatile flash memorydevices.

Electroacupuncture-Modulated MiR106b-5p Expression Enhances Autophagy by Targeting Beclin-1 to Promote Motor Function Recovery After Spinal Cord Injury in Rats

Shuhui Guo,Jianmin Chen,Ye Yang,Xiaolu Li,Yun Tang,Yuchang Gui,Jianquan Chen,Jianwen Xu 대한척추신경외과학회 2023 Neurospine Vol.20 No.3

Objective: Electroacupuncture (EA) has a definite effect on the treatment of spinal cord injuries (SCIs), but its underlying molecular mechanism remains unclear. Meanwhile, MiR-106b-5p is an autophagy- and apoptosis-related microribonucleic acid, but whether it regulates the progression of autophagy and apoptosis in SCIs is yet undetermined. As such, this study aimed to elucidate the involvement of miR-106b-5p in the EA treatment of an SCI. Methods: The miR-106b-5p level was detected by quantitative real-time polymerase chain reaction. In vitro, SH-SY5Y cells were transfected with miR-106b-5p mimics or inhibitors to regulate the miR-106b-5p expression, while in vivo, SCI rats were treated with EA for 7 days at the bilateral Zusanli (ST36) and Jiaji (EX-B2) acupoints. The motor function was evaluated using the Basso-Beattie-Bresnahan (BBB) criteria. Further, autophagic vacuoles, pathological damage, and neuronal cell morphology were observed by transmission electron microscopy, as well as by hematoxylin and eosin and Nissl staining, respectively. Results: The miR-106b-5p level, which can interact directly with Beclin-1 by influencing its expression, as well as the expressions of P62, Caspase-3, and Bax, was upregulated after an SCI, but it decreased after EA. Moreover, the ratio of LC3-II to LC3-I was upregulated after EA. EA can enhance autophagy, reduce neuronal apoptosis, and minimize motor dysfunction and histopathological deficits after an SCI. More importantly, however, all the above effects induced by EA can be reversed after an injection of miR-106-5p agomir to produce an overexpression of miR-106b-5p. Conclusion: EA treatment could downregulate miR-106b-5p to alleviate SCI-mediated injuries by promoting autophagy and inhibiting apoptosis.

Estrogen promotes the onset and development of idiopathic scoliosis via disproportionate endochondral ossification of the anterior and posterior column in a bipedal rat model

Shuhui Zheng,Hang Zhou,Bo Gao,Yongyong Li,Zhiheng Liao,Taifeng Zhou,Chengjie Lian,Zizhao Wu,Deying Su,Tingting Wang,Peiqiang Su,Caixia Xu 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

This study aimed to verify the effects of estrogen on the onset and development of adolescent idiopathic scoliosis and the mechanisms associated with these effects by constructing a pubescent bipedal rat model. Experiments were conducted to investigate whether scoliosis progression was prevented by a Triptorelin treatment. One hundred twenty bipedal rats were divided into female, OVX (ovariectomy), OVX + E2, Triptorelin, sham, and male groups. According to a spinal radiographic analysis, the scoliosis rates and curve severity of the female and OVX + E2 groups were higher than those in the OVX, Triptorelin, and male groups. The measurements obtained from the sagittal plane of thoracic vertebrae CT confirmed a relatively slower growth of the anterior elements and a faster growth of the posterior elements between T11 and T13 in the female and OVX + E2 groups than in the OVX and Triptorelin groups. Histomorphometry and immunohistochemistry revealed a significantly longer hypertrophic zone of the vertebral cartilage growth plates that expressed more type X collagen and less type II collagen in the OVX and Triptorelin groups than in the female and OVX + E2 groups. Ki67 immunostaining confirmed an increase in the proliferation of vertebral growth plate chondrocytes in the OVX group compared with the female and OVX + E2 groups. In conclusion, estrogen obviously increased the incidence of scoliosis and curve severity in pubescent bipedal rats. The underlying mechanism may be a loss of coupling of the endochondral ossification between the anterior and posterior columns. Triptorelin decreased the incidence of scoliosis and curve magnitudes in bipedal female rats. Introduction Adolescent

Responses of Low-Quality Soil Microbial Community Structure and Activities to Application of a Mixed Material of Humic Acid, Biochar, and Super Absorbent Polymer

Fangze Li,Shuhui Men,Shiwei Zhang,Juan Huang,Xuehua Puyang,Zhenqing Wu,Zhanbin Huang 한국미생물·생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.9

Low-quality soil for land reuse is a crucial problem in vegetation quality and especially to waste disposal sites in mining areas. It is necessary to find suitable materials to improve the soil quality and especially to increase soil microbial diversity and activity. In this study, pot experiments were conducted to investigate the effect of a mixed material of humic acid, super absorbent polymer and biochar on low-quality soil indexes and the microbial community response. The indexes included soil physicochemical properties and the corresponding plant growth. The results showed that the mixed material could improve chemical properties and physical structure of soil by increasing the bulk density, porosity, macro aggregate, and promote the mineralization of nutrient elements in soil. The best performance was achieved by adding 3 g·kg-1 super absorbent polymer, 3 g·kg-1 humic acid, and 10 g·kg-1 biochar to soil with plant total nitrogen, dry weight and height increased by 85.18%, 266.41% and 74.06%, respectively. Physicochemical properties caused changes in soil microbial diversity. Acidobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Firmicutes, Nitrospirae, Planctomycetes, and Proteobacteria were significantly positively correlated with most of the physical, chemical and plant indicators. Actinobacteria and Armatimonadetes were significantly negatively correlated with most measurement factors. Therefore, this study can contribute to improving the understanding of low-quality soil and how it affects soil microbial functions and sustainability.

Salp swarm algorithm with iterative mapping and local escaping for multi-level threshold image segmentation: a skin cancer dermoscopic case study

Hao Shuhui,Huang Changcheng,Heidari Ali Asghar,Chen Huiling,Li Lingzhi,Algarni Abeer D.,Elmannai Hela,Xu Suling 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.2

If found and treated early, fast-growing skin cancers can dramatically prolong patients’ lives. Dermoscopy is a convenient and reliable tool during the fore-period detection stage of skin cancer, so the efficient processing of digital images of dermoscopy is particularly critical to improving the level of a skin cancer diagnosis. Notably, image segmentation is a part of image preprocessing and essential technical support in the process of image processing. In addition, multi-threshold image segmentation (MIS) technology is extensively used due to its straightforward and effective features. Many academics have coupled different meta-heuristic algorithms with MIS to raise image segmentation quality. Nonetheless, these meta-heuristic algorithms frequently enter local optima. Therefore, this paper suggests an improved salp swarm algorithm (ILSSA) method that combines iterative mapping and local escaping operator to address this drawback. Besides, this paper also proposes the ILSSA-based MIS approach, which is triumphantly utilized to segment dermoscopic images of skin cancer. This method uses two-dimensional (2D) Kapur’s entropy as the objective function and employs non-local means 2D histogram to represent the image information. Furthermore, an array of benchmark function test experiments demonstrated that ILSSA could alleviate the local optimal problem more effectively than other compared algorithms. Afterward, the skin cancer dermoscopy image segmentation experiment displayed that the proposed ILSSA-based MIS method obtained superior segmentation results than other MIS peers and was more adaptable at different thresholds.

Tannic Acid and Ferrous Sulfate Modified Kapok Fiber for Oil-water Separation

Guizhen Ke,Shuhui Chen,Jiani Tang,Huanmin Li,Keshuai Liu 한국섬유공학회 2022 Fibers and polymers Vol.23 No.11

Biodegradable oil absorbing materials have attracted extensive attention in dealing with oil spill pollution. Todevelop more excellent oleophilic oil sorbent, the combination of tannic acid and ferrous sulfate was employed to treat therenewable and biodegradable natural kapok fiber. The as-prepared kapok showed superhydrophobic characteristics with highwater contact for the formation of tannic acid and ferrous ion complex on kapok surface, which was confirmed by scanningelectron microscopy observation and infrared spectroscopy and X-ray diffraction analysis. The preparation process of themodified kapok fiber was optimized. When the sodium chlorite pretreated kapok fiber was firstly treated with 4.25 g/l tannicacid and subsequently immersed in 4.25 g/l tannic acid and 6.25 g/l ferrous sulfate mixture at 60 °C for 15 min, the aspreparedkapok fiber presented the best oil absorption capacity and hydrophobicity (water contact angle 150.7 °). The treatedkapok had good adsorption capacity for oils and organic solvents, 48.2, 41.6, 53.4, 52.8, 49.2, 41.2 g/g for vegetable oil,diesel oil, silicone oil, carbon tetrachloride, DMF and n-hexane, respectively. In addition, the tannic acid and ferrous sulfatetreated kapok was recycled for six times through simple mechanical squeezing, and showed good oil-water separationperformance oil, indicating its potential application in the removal of spilled oil on water.