Modelling and Control of Nine-Switch Converter-Based DFIG Wind Power System

Dongliang Liu,Xu Zhang,Lei Pan,Aqiang Li 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.6

In this paper, nine-switch converter (NSC) is used to replace the Back-to-Back converter of DFIG wind power system. In order to simplify the control process and improve the performance, the switching function model of nine-switch converter under ABC coordinate system is established, and the mapping relationship between the parameters of NSC’s loads and those of DFIG wind energy conversion system is given. Meanwhile, a Resonant-proportional-integral (Resonant-PI) control strategy for NSC-based DFIG wind energy conversion system is proposed, and the PI controller is used for static control under steady state and the resonant controller for suppressing harmonic content in this method. The proposed method performs better than PI control in harmonic content and dynamic response. The simulations and experimental results verify the validity and reliability of the proposed mathematical model and control algorithm.

Correction to: Modelling and Control of Nine-Switch Converter-Based DFIG Wind Power System

Dongliang Liu,Xu Zhang,Pan Lei,Li Aqiang 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.2

Research Progress on Non-coding RNAs in Cholesteatoma of the Middle Ear

Dongliang Liu,Hang Zhang,Xiulan Ma,Yaodong Dong 대한이비인후과학회 2023 Clinical and Experimental Otorhinolaryngology Vol.16 No.2

Cholesteatoma of the middle ear is a common disease in otolaryngology that is receiving increasing attention. It is estimat-ed that over five million people around the world have suffered from middle ear cholesteatoma. The annual incidence ofmiddle ear cholesteatoma has been reported to be 9.2 per 100,000 in adults and 3 per 100,000 in children. Without timelydiscovery and intervention, cholesteatomas can become perilously large and damage intratemporal structures, causing vari-ous intracranial and extracranial complications. No practical nonsurgical treatments are currently available. Although multi-ple hypotheses exist, research directions have consistently focused on cell proliferation, apoptosis, and bone destruction. Non-coding RNAs (ncRNAs), especially microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs),have recently received increasing attention because of their key roles in gene expression, cell cycle regulation, and the de-velopment of many diseases. Although ncRNAs are not involved in protein translation, they are abundant in the genome,with only approximately 2% of genes encoding proteins and the remaining approximately 98% encoding ncRNAs. Thepurpose of this review is to summarize the current state of knowledge regarding the specific role of ncRNAs in middle earcholesteatoma.

Biodegradable cross-linked poly(L-lactide-co-e-caprolactone) networks for ureteral stent formed by gamma irradiation under vacuum

Xiliang Liu,Song Liu,Youkun Fan,Jin Qi,Xin Wang,Wei Bai,Dongliang Chen,Chengdong Xiong,Lifang Zhang 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.104 No.-

The poly(L-lactide-co-e-caprolactone) (PLCL) ureteral stent creeps and loses shape stability, increasingthe risk of stent tube dislocation. The rubbery biodegradable cross-linked PLCL networks were preparedthrough gamma irradiation under vacuum in the presence of trimethylolpropane triacrylate (TMPTA),pentaerythritol tetraacrylate (PET4A), and pentaerythritol triacrylate (PETA). At a standard sterilizationdose of 25 kGy, the gel content and network density of PLCL networks increased with increasingcrosslinking agent content (1, 3, 5, 7 wt%), and crosslinking efficiency decreased in the order ofPETA > PET4A > TMPTA. The average molecular weight (Mc ) between two crosslinks ranged from 2000to 105 g/mol. To perform the beneficial semi-interpenetrated polymer network and characterized bythe principle, the networks were processed in several doses (25, 50, 75, 100, and 125 kGy). In place ofthe Charlesby-Pinner equation, the irradiation cross-linking followed the Chen-Liu-Tang equation. ThePLCL network with 7 wt% PETA had a gel fraction of 83%, tensile strength of 34.7 MPa, and tensile setvalue as low as 5%. Furthermore, degradation in vitro was slowed down. Thus, PLCL networks with appropriateelasticity and flexibility, inherent biodegradability, and excellent biocompatibility can provide apromising alternative method for soft tissue repair engineering, such as ureteral stents.

Evidence of the genetic diversity and clonal population structure of Oenococcus oeni strains isolated from different wine-making regions of China

Dongliang Yu,Kan Shi,Xiangyuan Wen,Fangshu Xie,Tao Wang,Shuwen Liu,Ling He 한국미생물학회 2018 The journal of microbiology Vol.56 No.8

Studies of the genetic diversity and population structure of Oenococcus oeni (O. oeni) strains from China are lacking compared to other countries and regions. In this study, amplified fragment length polymorphism (AFLP) and multilocus sequence typing (MLST) methods were used to investigate the genetic diversity and regional evolutionary patterns of 38 O. oeni strains isolated from different wine-making regions in China. The results indicated that AFLP was markedly more efficient than MLST for typing O. oeni strains. AFLP distinguished 37 DNA patterns compared to 7 sequence types identified using MLST, corresponding to discriminatory indices of 0.999 and 0.602, respectively. The AFLP results revealed a high level of genetic diversity among the O. oeni strains from different regions of China, since two subpopulations and an intraspecific homology higher than 60% were observed. Phylogenetic analysis of the O. oeni strains using the MLST method also identified two major phylogroups, which were differentiated into two distinct clonal complexes by minimum spanning tree analysis. Neither intragenic nor intergenic recombination verified the existence of the clonal population structure of the O. oeni strains.

The topographic effect of ground motion based on Spectral Element Method

Liu, Xinrong,Jin, Meihai,Li, Dongliang,Hu, Yuanxin,Song, Jianxue Techno-Press 2017 Geomechanics & engineering Vol.13 No.3

A Spectral Element Method for 3D seismic wave propagation simulation is derived based on the three-dimensional fluctuating elastic dynamic equation. Considering the 3D real terrain and the attenuation characteristics of the medium, the topographic effect of Wenchuan earthquake is simulated by using the Spectral Element Method (SEM) algorithm and the ASTER DEM model. Results show that the high PGA (peak ground acceleration) region was distributed along the peak and the slope side away from the epicenter in the epicenter area. The overall distribution direction of high PGA and high PGV (peak ground velocity) region is parallel to the direction of the seismogenic fault. In the epicenter of the earthquake, the ground motion is to some extent amplified under the influence of the terrain. The amplification effect of the terrain on PGA is complicated. It does not exactly lead to amplification of PGA at the ridge and the summit or attenuation of PGA in the valley.

Information Dissemination Model of Microblogging with Internet Marketers

Dongliang Xu,Jingchang Pan,Bailing Wang,Meng Liu,Qinma Kang 한국정보처리학회 2019 Journal of information processing systems Vol.15 No.4

Microblogging services (such as Twitter) are the representative information communication networks duringthe Web 2.0 era, which have gained remarkable popularity. Weibo has become a popular platform forinformation dissemination in online social networks due to its large number of users. In this study, a microbloginformation dissemination model is presented. Related concepts are introduced and analyzed based on thedynamic model of infectious disease, and new influencing factors are proposed to improve the susceptibleinfective-removal (SIR) information dissemination model. Correlation analysis is conducted on the existinginformation dissemination risk and the rumor dissemination model of microblog. In this study, web hyper isused to model rumor dissemination. Finally, the experimental results illustrate the effectiveness of the methodin reducing the rumor dissemination of microblogs.

Information Dissemination Model of Microblogging with Internet Marketers

Xu, Dongliang,Pan, Jingchang,Wang, Bailing,Liu, Meng,Kang, Qinma Korea Information Processing Society 2019 Journal of information processing systems Vol.15 No.4

Microblogging services (such as Twitter) are the representative information communication networks during the Web 2.0 era, which have gained remarkable popularity. Weibo has become a popular platform for information dissemination in online social networks due to its large number of users. In this study, a microblog information dissemination model is presented. Related concepts are introduced and analyzed based on the dynamic model of infectious disease, and new influencing factors are proposed to improve the susceptible-infective-removal (SIR) information dissemination model. Correlation analysis is conducted on the existing information dissemination risk and the rumor dissemination model of microblog. In this study, web hyper is used to model rumor dissemination. Finally, the experimental results illustrate the effectiveness of the method in reducing the rumor dissemination of microblogs.

Optimized interfacial compatibility of carbon fiber and epoxy resin via controllable thickness and activated ingredients of polydopamine layer

Wu Dongliang,Xing Yuxuan,Zhang Denglu,Hao Zhenna,Dong Qi,Han Yongqin,Liu Lei,Wang Maoju,Zhang Ruliang 한국탄소학회 2024 Carbon Letters Vol.34 No.1

In this work, the trend in the performance of carbon fiber (CF) and its composite during self-polymerization of polydopamine (PDA) at carbon fiber surface was investigated by varying the self-polymerization time of dopamine in an aqueous solution. Research has shown that the PDA coating elevated the surface roughness and polarity of the inert fiber. The tensile strength of single carbon fiber was significantly improved, especially after 9 h of polydopamine self-polymerization, increasing by 18.64% compared with that of desized carbon fiber. Moreover, the interlaminar shear strength (ILSS) of CF-PDA9-based composites was 35.06% higher than that of desized CF-based composites. This research will provide a deep insight into the thickness and activated ingredients of dopamine oxidation and self-polymerization on interfacial compatibility of carbon fiber/epoxy resin composites.

Sintering technology and properties of sponge city permeable bricks prepared from electrical porcelain was

Yue Liu,Yun Xiang,Jieguang Song,Dongliang Zhang,Hongbin Wen,Yuzhen Wang 한양대학교 청정에너지연구소 2022 Journal of Ceramic Processing Research Vol.23 No.6

The generated electric porcelain waste increases with the rapid development of the electric porcelain industry. Unreasonableutilization results in the waste of resources and environmental pollution. However, at present, many coal gangues and fly ashesare wasted and underutilized in my country. In this paper, electric porcelain waste is used as the main raw material, and itssintering temperature, holding time, and heating rate are discussed to study the performance of the permeable brick preparedfrom electric porcelain waste. Results show that with the increase in sintering temperature, the porosity and waterpermeability coefficient of permeable bricks decrease, and their volume shrinkage rate and compressive strength show anincreasing trend. Furthermore, porosity decreases with the increase in holding time. The volume shrinkage rate andcompressive strength increase, and the water permeability coefficient decreases. The volume shrinkage rate of the permeablebrick decreases, and its porosity, water permeability coefficient, and compressive strength increase with the heating rate. Combined with the comprehensive consideration of the porosity, volume shrinkage rate, water permeability coefficient, andcompressive strength of permeable bricks, the best sintering process for preparing permeable bricks from electrical porcelainwaste is presented with a sintering temperature of 1225 °C, holding time of 1 h, and heating rate of 6 °C/min. The porosityof the prepared permeable brick is 79.5%, the volume shrinkage rate is 25.79%, the water permeability coefficient is 2.82×10-2cm/s, and the compressive strength is 5.79 MPa.