Equivalent and identification of integrated coupling parameter of variable speed constant frequency brushless doubly fed generator

Yiding Wang,Jianhui Su,Jidong Lai,Bao Xie,Yong Shi,Hongru Yu 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.1

Brushless doubly fed generator (BDFG) generally adopts double closed-loop vector control strategies. Owing to the influence of BDFG coupling parameters, the accuracy of feedforward decoupling parameters is very important; however, the complexity of the BDFG model makes its winding parameters difficult to identify. On the basis of the characteristics of the BDFG system control model and the decoupling control conditions, this study proposes a method for identifying the integrated coupling parameter. This method first uses particle swarm optimization to identify the coefficients of the current closed-loop transfer function. Then, the values of the integrated coupling parameters are calculated on the basis of the relationship between the coefficients of the current closed-loop transfer function and the integrated coupling parameters of the BDFG. This method bypasses the challenge of directly identifying BDFG winding parameters and can be used directly to design the controller. Experiments are performed using a 30 kW BDFG platform to prove the feasibility and effectiveness of the proposed method.

Analyses of Liquid and Vapor Flow in a Miniature Radially Rotating Heat Pipe for Turbine Blade Cooling Applications

Yiding Cao,Jian Ling,Won S. Chang 대한기계학회 1998 Heat transter conference Vol.6 No.1

Structural monitoring and analyses on the stability and health of a damaged railway tunnel

Zhao, Yiding,Yang, Junsheng,Zhang, Yongxing,Yi, Zhou Techno-Press 2021 Advances in concrete construction Vol.11 No.5

In this paper, a study of stability and health of a newly-built railway tunnel is presented. The field test was implemented to monitor the secondary lining due to the significant cracking behaviors influenced the stability and health of the tunnel structure. Surface strain gauges were installed for monitoring the status of crack openings, and the monitoring outputs demonstrated that the cracks were still in the developing stage. Additionally, adjacent tunnel and poor condition of surrounding rock were identified as the causes of the lining cracking by systematically characterizing the crack spatial distribution, tunnel site and surrounding rock conditions. Reconstruction of partial lining and reconstruction of the whole secondary lining were designed as the maintenance projects for different cracking regions based on the construction feasibility. For assessing the health conditions of the reinforced lining, embedded strain gauges were set up to continuously measure the strain and the internal force of the reconstructed structures. For the partially reconstructed lining, the outputs show the maximum tensile elongation is 0.018 mm during 227 days, which means the structure has no obvious deformation after maintenance. The one-year monitoring of full-section was implemented in the other two completely reconstructed cross-sections by embedded strain gauge. The outputs show the reconstructed secondary lining has undertaken the pressure of surrounding rock with the time passing. According to the calculated compressive and tensile safety factors, the completely reconstructed lining has been in reliable and safe condition during the past year after reinforcement. It can conclude that the aforementioned maintenance projects can effectively ensure the stability and health of this tunnel.

Fracture behaviors of tunnel lining caused by multi-factors: A case study

Zhao, Yiding,Zhang, Yongxing,Yang, Junsheng Techno-Press 2019 Advances in concrete construction Vol.8 No.4

The cracking and spalling caused by fracture of concrete lining have adverse impacts on serviceability and durability of the tunnel, and the subsequent maintenance work for damaged structure needs to be specific to the damaging causes. In this paper, a particular case study of an operational tunnel structure is presented for the serious cracking and spalling behaviours of concrete lining, focusing on the multi-factors inducing lining failure. An integrated field investigation is implemented to characterize the spatial distribution of damages and detailed site situations. According to results of nondestructive inspection, insufficient lining thickness and cavity behind lining are the coupled-inducement of lining failure bahaviors. To further understanding of the lining structure performance influenced by these multiple construction deficiencies, a reliable numerical simulation based on extended finite element method (XFEM) is performed by using the finite element software. The numerical model with 112 m longitudinal calculation, 100 m vertical calculation and 43 m vertical depth, and the concrete lining with 1450 solid elements are set enrichment shape function for the aim of simulating cracking behavior. The numerical simulation responses are essentially in accordance with the actual lining damaging forms, especially including a complete evolutionary process of lining spalling. This work demonstrates that the serious lining damaging behaviors are directly caused by a combination of insufficient thickness lining and cavity around the surrounding rocks. Ultimately, specific maintenance work is design based on the construction deficiencies, and that is confirmed as an efficient, time-saving and safe maintenance method in the operational railway tunnel.

Research on grain composition, grain size and electrical conductivity of the CuCr1-xMgxO2 (0 ≤ x ≤ 0.08)

Yanyan Tang,Yiding Hu,Yi Li,Haorong Wu,Liangwei Chen,Lan Yu 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.5

A series of layered CuCr1-xMgxO2 (0 ≤ x ≤ 0.08) polycrystalline ceramics were prepared. The effects of substituting Mg2+cations for Cr3+ cations on the grain composition, grain size, grain quantity, and electrical conductivity were investigated. When x = 0–0.04, the distinct layered structure grain grew rapidly with the increase of magnesium in the composition, andthe average grain size increased from 2.5 μm (x = 0) to 15 μm (x = 0.04) due to the decrease of activation energy. Furthermore,the bulk density and lattice constant also reached the maximum and minimum values of 4.367 g/cm3 and 17.083 respectivelyat x = 0.04. When x = 0.05–0.08, the average grain size slightly decreased due to the grown-up second-phase MgCr2O4hindering of grain growth. The results showed that the average size of the second-phase MgCr2O4 had reached 1.3 μm whenx = 0.04. In general, the larger the grain size of polycrystalline ceramics, the more defects in the grain boundaries, and thebetter its electrical conductivity. Therefore, the solid-phase reaction, which can obtain larger grain size and more grainboundary defects, was chosen here to prepare CuCr1-xMgxO2 polycrystalline ceramics, so as to obtain a highly conductiveCuCr1-xMgxO2 ceramic material. The minimum resistivity of the obtained CuCr0.6Mg0.4O2 polycrystalline ceramic is only 0.091Ω·cm, which is of great significance for the development of transparent conductive oxides.

Effect of Acrylic Content on the Properties of the Polyurethane/Polyacrylate Composite Emulsion

Guoyan Ma,Yiding Shen,Ruimin Gao,Xiaorong Wang 한국고분자학회 2017 폴리머 Vol.41 No.1

A polyurethane/polyacrylate (PUA) composite emulsion was synthesized by using polyurethane (PU) as seeds with soap-free emulsion polymerization, in which methyl methacrylate (MMA) and butyl acrylate (BA) were used as main acrylic monomers. The effect of acrylic contents and “stiff” and “soft” weight ratio of acrylic monomers on the properties of the films were investigated. The Fourier transform infrared (FTIR) results showed that acrylic monomers were involved in the emulsion copolymerization. The optimum composition of PUA composite formation was obtained when the polyacrylate (PA) content was 20%, in which the weight ratio of MMA and BA was 2/1. With the increment of PA content, the decomposition temperature increased.

R-EPS용 토션 바의 휨 측정 및 교정 연구

남궁재규(JaeGyu Namgung),류일정(Yiding Liu),전태호(Taeho Jeon),이형욱(Hyoungwook Lee) 한국자동차공학회 2021 한국자동차공학회 학술대회 및 전시회 Vol.2021 No.11

Conductively coupled flexible silicon electronic systems for chronic neural electrophysiology

Li, Jinghua,Song, Enming,Chiang, Chia-Han,Yu, Ki Jun,Koo, Jahyun,Du, Haina,Zhong, Yishan,Hill, Mackenna,Wang, Charles,Zhang, Jize,Chen, Yisong,Tian, Limei,Zhong, Yiding,Fang, Guanhua,Viventi, Jonathan National Academy of Sciences 2018 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.115 No.41

<P>Materials and structures that enable long-term, intimate coupling of flexible electronic devices to biological systems are critically important to the development of advanced biomedical implants for biological research and for clinical medicine. By comparison with simple interfaces based on arrays of passive electrodes, the active electronics in such systems provide powerful and sometimes essential levels of functionality; they also demand long-lived, perfect biofluid barriers to prevent corrosive degradation of the active materials and electrical damage to the adjacent tissues. Recent reports describe strategies that enable relevant capabilities in flexible electronic systems, but only for capacitively coupled interfaces. Here, we introduce schemes that exploit patterns of highly doped silicon nanomembranes chemically bonded to thin, thermally grown layers of SiO2 as leakage-free, chronically stable, conductively coupled interfaces. The results can naturally support high-performance, flexible silicon electronic systems capable of amplified sensing and active matrix multiplexing in biopotential recording and in stimulation via Faradaic charge injection. Systematic in vitro studies highlight key considerations in the materials science and the electrical designs for high-fidelity, chronic operation. The results provide a versatile route to biointegrated forms of flexible electronics that can incorporate the most advanced silicon device technologies with broad applications in electrical interfaces to the brain and to other organ systems.</P>

A Scheduling Model of the Icebreaker Assistance Service in the Northern Sea Route

Yi Ding,Weiwen Zhou,Dongmin Xu,Guolong Lin 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.4

The melting of the sea ice in the Arctic area increases the possibility of exploiting the Northern Sea Route (NSR)by economic method. Compared to the traditional routes, navigating through the Northern Sea Route (NSR) will save much distance and time from Asia to Europe, but the ice condition along the NSR is a key obstacle to most vessels. To ensure the safety of the navigation, ice breaker assistance service becomes crucial. This paper introduces the procedure of icebreaker assistance service firstly, and then a static scheduling model is presented to illustrate icebreaker assistance service. Considering real operation, a dynamic model is proposed, and First Come First Serve (FCFS) principle is implemented into models. The experiment results show that this model is beneficial to control the average waiting time, while it may leads to wait too long for some vessels. And the average fuel cost of each trip remains stable even increasing service request.

Effect of Store Environments on Tourists Impulsive Buying, Self-control and Shopping Satisfaction, Loyalty

Yi Ding,YANWENYAN,윤유식,이재희 한국자료분석학회 2017 Journal of the Korean Data Analysis Society Vol.19 No.4

The study is to research the extent and degree of store environment factors (sensory, layout and design) effect tourists’ self-control and impulsive buying, and the effect of self-control as a mediator variable in the process of impulsive buying, in the famous tourism destinations, Myeong-dong and Dong-dae-mun. The performance after impulsive buying and self-control of tourists also are included. Data were collected by a questionnaire from 322 participants (international tourists) in the 5 target department stores in Myeong-dong and Dong-dae-mun, Seoul. The models and hypotheses were tested and results showed that first, tourists are always notice, receive and believe the more intuitive experience, and leave a deep expression for their impulsive buying behavior. Second, the change of self-control has a significant impact on impulsive buying behavior. Third, tourists can accept and recognize their self-control behavior after they control their shopping desire. Fourth, tourists do not regret about their impulsive buying behavior, which contains a kind of new shopping concept, for being loyal to the present feelings and their own preferences.