Time-inconsistent Output Subsidy/Tax Policies in Free-entry Mixed Markets

Jiaqi Chen,Sang-Ho Lee,Timur K. Muminov 한국산업경제학회 2018 한국산업경제학회 정기학술발표대회 논문집 Vol.2018 No.12

Acupuncture combined with speech rehabilitation training for post-stroke dysarthria: a systematic review and meta-analysis of randomized controlled trials

Qianwen Xie,Xueyin Chen,Jingmin Xiao,Shaonan Liu,Lihong Yang,Jing Chen,Jiaqi Lai,Rui Lan,Yi Chen,Haifang Yang,Xinfeng Guo 한국한의학연구원 2020 Integrative Medicine Research Vol.9 No.4

Background: The evidence of Acupuncture combined with speech rehabilitation training for post-stroke dysarthria is insufficient and there is no consensus on its efficacy. Methods: We searched seven Chinese and English medicine databases for randomized controlled trials (RCTs) from their inception to November 2019. The primary outcome measure was the clinical response rate, assessed with the Frenchay Dysarthria Assessment (FDA) tool. We assessed risk of bias using the Cochrane risk-of-bias tool. We used GRADE to assess the certainty of evidence (CoE). Results: Thirty studies were included in this systematic review, 23 of which were pooled in meta-analysis. Acupuncture combined with speech rehabilitation training is likely beneficial for was response rate (n = 1685; RR = 1.37; 95% CI [1.29, 1.46], P < 0.01, I2 = 34%; 17 studies, low CoE) compared to speech rehabilitation treatment alone. Conclusion: The combination of acupuncture and speech rehabilitation training may improve total response rate of stroke patients with dysarthria. However, more RCTs with rigorous study design and validated outcome measures are needed to confirm the evidence.

An Automatic Corona-discharge Detection System for Railways Based on Solar-blind Ultraviolet Detection

Jiaqi Li,Yue Zhou,Xiangyu Yi,Mingchao Zhang,Xue Chen,Muhan Cui,Feng Yan 한국광학회 2017 Current Optics and Photonics Vol.1 No.3

Corona discharge is always a sign of failure processes of high-voltage electrical apparatus, includingthose utilized in electric railway systems. Solar-blind ultraviolet (UV) cameras are effective tools for coronainspection. In this work, we present an automatic railway corona-discharge detection system based on solarblindultraviolet detection. The UV camera, mounted on top of a train, inspects the electrical apparatus,including transmission lines and insulators, along the railway during fast cruising of the train. An algorithmbased on the Hough transform is proposed for distinguishing the emitting objects (corona discharge) fromthe noise. The detection system can report the suspected corona discharge in real time during fast cruises. An experiment was carried out during a routine inspection of railway apparatus in Xinjiang Province, China. Several corona-discharge points were found along the railway. The false-alarm rate was controlled to lessthan one time per hour during this inspection.

Study of Distribution Model under Disaster Relief Logistics System

Lingling-Chen,Jiaqi-Yang,Jianjun-Liu 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.11

This paper mainly using the supplies distribution model in emergency situation, conducted a in-depth research on the problem of supplies distribution in the disaster relief, including single supplies and multiple supplies respectively with and without transport capacity constraints, and then implement its calculation through computer program; next, emergency supplies distribution model of multiple target and dynamic conditions is discussed in further, that is to say, considering some conditions such as the road condition change in the existing logistics system when disasters occur, in this case, the disaster relief supplies distribution model of object-oriented is introduced to guarantee the supplies. At present, there is still no systematic disaster relief logistics system in our country, so the study results of this paper have a certain reference value to the build and implementation of disaster relief logistic system in our country.

Frequency capture characteristic of a vibration system driven by four counterrotating unbalanced rotors

Xiaozhe Chen,Junqi Liu,Jiaqi Zhang,Baitong Zhou 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

This study investigates the frequency capture characteristic of four unbalanced rotors in multi-frequency ranges. First, using the average method, the synchronous condition of four unbalanced rotors in a vibration system is derived. Then, the stability condition of the vibration system is deduced, which meets the Routh-Hurwitz criterion. On the basis of the theoretical analysis, the phase difference in steady states and the resultant force on the rigid body at different excitation frequency regions are discussed numerically. Five sets of experiments are done to investigate synchronization and the Sommerfeld effect. The results prove that the vibration system has three motion states according to the excitation frequency in different frequency regions. Two stable states appear in the near-resonance region of the system. This study concludes that the synchronization of unbalanced rotors formed before and after the natural frequency is crucial for the occurrence of the Sommerfeld effect. This work can provide theoretical and experimental reference for the design of new vibration equipment in engineering.

A Ultra-Low Specific On-Resistance and Extended Gate SJ LDMOS Structure

Lijuan Wu,Jiaqi Chen,Hang Yang,QiLin Ding,Xing Chen,Shaolian Su 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.3

A new structure of extended gate (EG) SJ LDMOS is proposed in this paper to overcome the substrate assisted depletion (SAD) eff ect in the structure of Super-Junction lateral double diff used metal oxide semiconductor (SJ LDMOS). Different from other surface SJ structures, the SJ layer of the structure is located in the body of the drift region. Gate oxide and silicon layer form the EG Structure-Oxide-Semiconductor structure that is similar to Metal–Insulator–Semiconductor capacitor. The the N-drift of the EG structure can obtain the charge compensation to overcome the SAD eff ect, and a nearly rectangular electric field is achieved. In the on-state, the EG structure has two conductive channels and the accumulation layer is formed on the drift region. By accumulating high concentration electrons in the channels, the specifi con-resistance ( R ON,sp ) is greatly reduced. When the drift length is 24 μm, 431.4 V breakdown voltage ( V B ) and 9.8 mΩ cm 2 R ON,sp are achieved, and the fi gure of merit is 18.9 MW cm −2 .

Modal Analysis of Resonance and Stable Domain Calculation of Active Damping in Multi-inverter Grid-connected Systems

Wu, Jian,Chen, Tao,Han, Wanqin,Zhao, Jiaqi,Li, Binbin,Xu, Dianguo The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

Interaction among multiple grid-connected inverters has a negative impact on the stable operations and power quality of a power grid. The interrelated influences of inverter inductor-capacitor-inductor filters constitute a high-order power network, and consequently, excite complex resonances at various frequencies. This study first establishes a micro-grid admittance matrix, in which inverters use deadbeat control. Multiple resonances can then be evaluated via modal analysis. For the active damping method applied to deadbeat control, the sampling frequency and the stable domain of the virtual damping ratio are also presented by analyzing system stability in the discrete domain. Simulation and experimental results confirm the efficiency of modal analysis and stable domain calculation in multi-inverter grid-connected systems.

Sulfonated polysulfone proton exchange membrane with flexible side chains for fuel cells

Zongwen Qiao,Jiaqi Deng,Tao Chen 한국고분자학회 2024 Macromolecular Research Vol.32 No.2

In this study, chloromethylated polysulfones (CPS) were used as precursors to synthesize two kinds of sulfonated polysulfones with flexible side chains, namely PS-BS (The end of the side chain contains a sulfonic acid group) and PS-BDS (The end of the side chain contains two sulfonic acid groups). This was achieved through nucleophilic substitution reaction using sodium 4-hydroxybenzenesulfonate and disodium 1,2-dihydroxybenzene-3,5-disufonate as nucleophilic reagents, respectively. The chemical structures of the resulting sulfonated polysulfones were characterized using the Fourier infrared spectrum (FT-IR) and nuclear magnetic hydrogen spectrum ( H1-NMR). The proton exchange membranes (PEMs) were fabricated using a solution casting method. Thermogravimetric analysis (TGA) analysis revealed that the obtained PEMs exhibited stability up to 270 °C. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis indicated that PS-BS and PS-BDS PEMs exhibited a clear microphase separation structure, with the hydrophilic sulfonic acid groups located far away from the hydrophobic main chain of PS. This unique structure contributed to improved dimensional stability and oxidative stability of the PEMs. The obtained PEMs show better dimensional stability and oxidative stability. Comparing the two types of PEMs at the same temperature and ion exchange capacity (IEC), PS-BDS PEMs demonstrate better dimensional stability and lower methanol permeability compared to PS-BS PEMs. For instance, PD-BDS-4 PEMs exhibited a dimensional of stability up to 8.6% at room temperature and 30% at 85 °C. The corresponding methanol permeability was 10.29 × 10– 7 cm2/ s at 25 °C, which was significantly lower than that of Nafion112 (10.5 × 10– 7 cm2/ s) PEMs under the same condition.

Resonance Characteristics Analysis of Grid-connected Inverter Systems based on Sensitivity Theory

Wu, Jian,Han, Wanqin,Chen, Tao,Zhao, Jiaqi,Li, Binbin,Xu, Dianguo The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3

Harmonic resonance exists in grid-connected inverter systems. In order to determine the network components that contribute to harmonic resonance and the composition of the resonant circuit, sensitivity theory is applied to the resonance characteristic analysis. Based on the modal analysis, the theory of sensitivity is applied to derive a formula for determining the sensitivities of each network component parameter under a resonance circumstance that reflects the participation of the network component. The solving formula is derived for both parallel harmonic resonance and series harmonic resonance. This formula is adopted to a 4-node grid-connected test system. The analysis results reveal that for a certain frequency, the participation of parallel resonance and series resonance are not the same. Finally, experimental results demonstrate that the solving formula for sensitivity is feasible for grid-connected systems.

Modal Analysis of Resonance and Stable Domain Calculation of Active Damping in Multi-inverter Grid-connected Systems

Jian Wu,Tao Chen,Wanqin Han,Jiaqi Zhao,Binbin Li,Dianguo Xu 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.1

Interaction among multiple grid-connected inverters has a negative impact on the stable operations and power quality of a power grid. The interrelated influences of inverter inductor–capacitor–inductor filters constitute a high-order power network, and consequently, excite complex resonances at various frequencies. This study first establishes a micro-grid admittance matrix, in which inverters use deadbeat control. Multiple resonances can then be evaluated via modal analysis. For the active damping method applied to deadbeat control, the sampling frequency and the stable domain of the virtual damping ratio are also presented by analyzing system stability in the discrete domain. Simulation and experimental results confirm the efficiency of modal analysis and stable domain calculation in multi-inverter grid-connected systems.