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Gao Guodong,Xing Yongming 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.4
In this study, we designed a special stress concentration specimen. We studied the stress, strain, craze density, and the change trend in the rate of acoustic emission events in the area with the most intense craze damage. We also examined the evolution of crazing damage under continuous loading. We determined the one-to-one correspondence between crazing and the degree of triaxial stress, and used the finite element method to validate this correspondence. In addition, we analyzed the viscoelasticity area of the specimen and proposed the fracture criteria for crazes and microcracks.
Leakage Magnetic Field Suppression Using Dual-Transmitter Topology in EV Wireless Charging
Guodong Zhu,Dawei Gao,Shulin Lin 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.3
This paper proposes an active leakage magnetic field (LMF) suppression scheme, which uses the dual-transmitter (DT) topology, for EV wireless charging systems (EVWCS). The two transmitter coils are coplanar, concentric and driven by separate inverters. The LMF components generated by the three coils cancel each other out to reduce the total field strength. This paper gives a detailed theoretical analysis on the operating principles of the proposed scheme. Finite element analysis is used to simulate the LMF distribution patterns. Experimental results show that when there is no coil misalignment, 97% of the LMF strength can be suppressed in a 1kW prototype. These results also show that the impact on efficiency is small. The trade-off between LMF suppression and efficiency is revealed, and a control strategy to balance these two objectives is presented.
Zhu, Guodong,Gao, Dawei The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.1
Using a reactive coil to suppress the leakage magnetic field (LMF) in wireless power transfer is practical, but the suppression capability reported in the literature is still limited. This paper proposes several methods for improving the suppression capability of this scheme. Three conditions are required to realize this goal, namely (1) a good LMF proportionality, (2) an equation regarding the LMF coefficients and mutual inductances, and (3) an equation regarding the impedance of the reactive coil loop. Coil geometry optimization is performed to meet condition (2), and coil reactance is compensated by a capacitor to meet condition (3). Given the trade-off between LMF suppression capability and efficiency, a control strategy based on a switching capacitor array is adopted. In the experiments, a 97.5% reduction in the LMF strength is achieved on the measurement point with slight effects on efficiency.
Leakage Magnetic Field Suppression Using Dual-Transmitter Topology in EV Wireless Charging
Zhu, Guodong,Gao, Dawei,Lin, Shulin The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.3
This paper proposes an active leakage magnetic field (LMF) suppression scheme, which uses the dual-transmitter (DT) topology, for EV wireless charging systems (EVWCS). The two transmitter coils are coplanar, concentric and driven by separate inverters. The LMF components generated by the three coils cancel each other out to reduce the total field strength. This paper gives a detailed theoretical analysis on the operating principles of the proposed scheme. Finite element analysis is used to simulate the LMF distribution patterns. Experimental results show that when there is no coil misalignment, 97% of the LMF strength can be suppressed in a 1kW prototype. These results also show that the impact on efficiency is small. The trade-off between LMF suppression and efficiency is revealed, and a control strategy to balance these two objectives is presented.
( Pankajkumar Ramdas Waghmare ),( Pratima Pankajkumar Waghmare ),( Liwei Gao ),( Wan Sun ),( Yuqi Qin ),( Guodong Liu ),( Yinbo Qu ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.5
Efficient cellulolytic enzyme production is important for the development of lignocellulose-degrading enzyme mixtures. However, purification of cellulases from their native hosts is time- and labor-consuming. In this study, a constitutive expression system was developed in Penicillium oxalicum for the secreted production of proteins. Using a constitutive polyubiquitin gene promoter and cultivating with glucose as the sole carbon source, nine cellulolytic enzymes of different origins with relatively high purity were produced within 48 h. When supplemented to a commercial cellulase preparation, cellobiohydrolase I from P. funiculosum and cellobiohydrolase II from Talaromyces verruculosus showed remarkable enhancing effects on the hydrolysis of steam-exploded corn stover. Additionally, a synergistic effect was observed for these two cellobiohydrolases during the hydrolysis. Taken together, the constitutive expression system provides a convenient tool for the production of cellulolytic enzymes, which is expected to be useful in the development of highly efficient lignocellulose-degrading enzyme mixtures.
The Single Center Experience of One Thousand Cases of Robotic Pancreatectomy
( Rong Liu ),( Sai Chou ),( Zhiming Zhao ),( Guodong Zhao ),( Yuanxing Gao ) 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1
Aims: Operation plan for pancreatic tumor used to be divided in four main type,pancreaticoduodenectomy (PD),central pancreatectomy,distal pancreatectomy (DP) and pancreatic enucleation. To evaluate the value of da Vinci robotic surgery system in pancreatectomy. Methods: The clinical data of a consecutive of 1000patients who underwent robotic-assisted pancreatectomy from Novem-ber, 2011 to September 2017 were retrospectively reviewed. All the operations were performed by the same team, which mainly approach in Da Vinci robotic system Si. The demographic characteristics, intraoperative blood loss, operative duration, post-operative hospital stay, blood transfusion details, and conversion rate were all analyzed. Results: A total of 1000 patients were included in this study, with an average age of 54.0, and 486 cases of them were male. The average operative time was 3.5 hours (2-7 h), the estimated blood loss was 100ml (20-1200 ml), and the postoperative hospital stay was 9.3 days in average. Overall complication morbidity was 7.9% (79/1000) and 6.7%(67/1000) cases suffered from grade B-C Pancreatic fistula, with the conversion rate of 3.2% and 30-Day mortality rate of 0.42%. Conclusions: Robotic pancreatectomy could be successfully performed with the assistance of da Vinci surgery system, the operative duration, post-operative hospital stay and intraoperative blood loss were satisfying, with very patients died in 30 days and very operations converted.
Critical seismic incidence angle of transmission tower based on shaking table tests
Li Tian,Xu Dong,Haiyang Pan,Guodong Gao,Aiqiang Xin 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.76 No.2
Transmission tower-line systems have come to represent one of the most important infrastructures in today’s society. Recent strong earthquakes revealed that transmission tower-line systems are vulnerable to earthquake excitations, and that ground motions may arrive at such structures from any direction during an earthquake event. Considering these premises, this paper presents experimental and numerical studies on the dynamic responses of a 1000 kV ultrahigh-voltage (UHV) transmission tower-line system under different seismic incidence angles. Specifically, a 1:25 reduced-scale experimental prototype model is designed and manufactured, and a series of shaking table tests are carried out. The influence of the seismic incidence angle on the dynamic structural response is discussed based on the experimental data. Additionally, the incidence angles corresponding to the maximum peak displacement of the top of the tower relative to the ground (referred to herein as the critical seismic incidence angles) are summarized. The experimental results demonstrate that seismic incidence angle has a significant influence on the dynamic responses of transmission tower-line systems. Subsequently, an approximation method is employed to orient the critical seismic incidence angle, and a corresponding finite element (FE) analysis is carried out. The angles obtained from the approximation method are compared with those acquired from the numerical simulation and shaking table tests, and good agreement is observed. The results demonstrate that the approximation method can properly predict the critical seismic incidence angles of transmission tower-line systems. This research enriches the available experimental data and provides a simple and convenient method to assess the seismic performance of UHV transmission systems.
Guo Qiang Zhu,Li Bingyu,Shen Ming,Li Weizheng,Gao Qiang,Xu Guodong 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.6
A series of bowl-shaped porous carbon materials was successfully synthesized by the use of didodecyldimethylammonium bromide as the soft template agent. By controlling the dosage of the soft template agent and the water/ethanol ratio of the solvent, the size and structure of the carbon materials can be precisely controlled. The prepared carbon materials with stacked bowl structure have good specific surface area (1,380.20 m2 g−1), large pore volume (1.27 cm3 g−1) and high heteroatom N doping amount (6.68 at.%). Moreover, electrochemical tests in 6 M KOH demonstrated impressive electrochemical performance, where the specific capacity of the typical materials was measured to be 191.0 F g−1 (at the current density of 1 A g−1), and the capacity retention rate of typical materials was 80% (at the current density of 10 A g−1).