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Novel flexible HVDC transmission converter station topology with DC fault blocking capability
Huo, Qunhai,Wang, Peng,Cao, Guoen,Zhu, Jin,Yin, Jingyuan,Guo, Xinming,Wei, Tongzhen The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.4
The conventional half-bridge submodule (HBSM)-based multilevel modular converter (MMC) cannot block DC faults. To solve this problem, a novel flexible overhead-line high-voltage direct current (HVDC) transmission converter station topology is proposed in this study, which provides DC fault blocking capability. By adding blocking submodules (SMs) onto the positive and negative DC buses of a conventional HBSM converter station, a rapid fault current blocking can be achieved in the case of a DC bus short circuit. The DC fault blocking principle of the proposed topology and the rapid fault blocking capability of the blocking SM are analyzed. The quantity of required major components is also calculated. In addition, the IGBT, the system loss and the control complexity quantities are comprehensively compared with those of existing topologies. The validity of the proposed topology is demonstrated based on simulation and experimental studies.
Wei, Guo-Li,Huang, Xin-En,Huo, Jie-Ge,Wang, Xiao-Ning,Tang, Jin-Hai Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.5
Purpose: This study was to determine the efficacy and safety of pemetrexed based chemotherapy in treating patients with metastatic gastric cancer who failed to respond to first and (or) second line chemotherapy. Patients and Methods: Metastatic gastric cancer patients who failed first and (or) second line chemotherapy, were enrolled. All patients were recruited from Jiangsu Cancer Hospital & Research Institute, and were treated with pemetrexed $500mg/m2$ (intravenous; on day 1), and a platinum (or irinotecan) every 3 weeks until disease progression, or intolerable toxicity. Evaluation on efficacy was conducted after two cycles of chemotherapy using the Response Evaluation Criteria for Solid Tumors. Toxicity was recorded according to National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0. Results: From Jun 2011 to May 2013, 23 patients were enrolled. All eligible 23 patients completed at least 2 cycles of chemotherapy with pemetrexed based chemotherapy, and were evaluable. Their median age was 55 years (range 40 to 78 years). Seventeen patients were male and 6 female. Three patients (13%) achieved partial response, five patients (22%) stable, 15 patients (65%) with disease progression, and none with complete response. Grade 2 neutrophil suppression occurred in 4.3%, grade 3 in 13% of patients, and no grade 4 was reported. Thrombocytopenia was encountered as follows: 4.3% grade 2, 4.3% grade 3 and 4.3% grade 4. Incidence of anemia was 34.8% in grade 2, 8.7% grade 3 and 0% grade 4. Only 4.3% of patients required packed red blood cell infusion. Elevated transaminase were 4.3% in grade 2 and 0% in grade 3 or 4. Other toxicity included oral mucositis. Conclusions: Pemetrexed based chemotherapy is mildly effective in treating patients with metastatic gastric cancer with tolerable toxicity.
Wei Sun,Chunhui Huo,Yang Yu 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.12
To investigate the reasonable method for selecting persons in organization personnel training, our study focuses on the formulation of personnel selection in organization personnel training based on knowledge supernetwork. First, this paper states the process of constructing organization training supernetwork and formulates the model for selecting single person. Subsequently, we establish the model for selecting multiple persons based on training knowledge supernetwork and analyze the complexity and the shortcomings in detail. Third, to improve the accuracy of personnel selection, we build the model for selecting multiple persons based on step-by-step method and analyze the complexity. Final, the proposed models are verified by an application case.
Wei Sun,Junzhou Huo,Jing Chen,Zhen Li,Xu Zhang,Li Guo,Haifeng Zhao,Yu Zhao 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.2
In rock TBM design the disc cutters’ layout design of the full-face rock tunnel boring machine (TBM) is one of the key technologies. However, there are few published papers in literatures for various reasons. In this paper, based on the engineering technical requirements and the corresponding cutter head’s structure design requirements, a nonlinear multi-objective disc cutters’ layout mathematical model with complex constraints and the corresponding multi-stage solution strategy are presented, in which the whole disc cutters’ layout design process is decomposed into the disc cutters’ spacing design and the disc cutters’ plane layout design. A numerical simulation method based on the FEM theory is adopted to simulate the rock chipping process induced by three TBM disc cutters to determine the optimal cutter spacing. And a cooperative coevolutionary genetic algorithm (CCGA) is adopted to solve the disc cutters’ plane layout design problem. Finally, a disc cutters’ layout design instance of the TBM is presented to demonstrate the feasibility and effectiveness of the proposed method. The computational results show that the proposed method can be used to solve the disc cutters’ layout design problem of the TBM and provide various layout schemes within short running times for the engineers to choose from.
Management of Basic Scientific Research Achievements Based on Knowledge Supernetwork
Wei Sun,Chunhui Huo,Yang Yu 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.11
Basic scientific research achievements management involves multiple knowledge resources. We propose a knowledge supernetwork model to integrate multiple knowledge resources. First, person network, material carrier network, and knowledge element network are established. Subsequently, the knowledge supernetwork is constructed to integrate the above three networks. Second, the characteristics of knowledge supernetwork are investigated from the perspective of the quantitative analysis. Based on the knowledge supernetwork, some methods for solving real problems are developed. Finally, we construct a knowledge supernetwork model using real basic scientific research achievement files. The methods of knowledge representation, basic scientific research proposal grouping, and knowledge classification are proposed to illustrate how to manage basic scientific research achievement from the perspective of knowledge.
Junzhou Huo,Wei Sun,Jing Chen,Pengcheng Su,Liying Deng 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.2
Improving of the quality of the disc cutters’ plane layout design of the full-face rock tunnel boring machine (TBM) is the most effective way to improve the global performance of a TBM. The plane layout design of disc cutters contains multiple complex engineering technical requirements and belongs to a multi-objective optimization problem with multiple nonlinear constraints. Based on analysis of the technical requirements of the plane layout problem, an optimizing mathematical model was built. To obtain a set of design schemes for engineers to choose from, a multi-objective genetic algorithm (MOGA) was applied to carry out the optimization of the mathematical model. A constraint-domination principle was utilized to handle the constraints, and a nondominated sorting method was adopted to obtain Pareto solutions. Simulation results showed that the proposed method was efficient and accurate in obtaining the Pareto layout solutions.
Junzhou Huo,Hanyang Wu,Jing Yang,Wei Sun,Guangqing Li,Xiaolong Sun 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.8
The core component, TBM cutterhead, bears a multi-directional impact load because of its direct contact with rock during tunneling. Unreasonable cutter design and parameter set lead to severe vibration or abnormal injury during excavation, seriously affecting the efficiencyof the TBM tunneling. Therefore, study of cutterhead dynamics response under impact loads is one of the core content of TBMsystem design. TBM multi-degree-of-freedom coupled dynamic model contains different geological conditions, cutter speed, body mass,time-varying mesh stiffness, transmission error, etc. A method is proposed to solve the problem based on Newmark algorithm, whichfurther improves the solution efficiency. A tunneling field test was conducted, and the results verify the correctness of the model and thesimplified cutter system. The simulation results of the Dahuofang project show that: ① The calculation process of Newmark is simplified,the calculation speed increased 3-4 orders of magnitude higher than Runge-Kutta method, while the solving time was reduced from2.6e5 s to 155 s under the same precision; ② Compared with the results of two kinds of rock with compressive strength 150 MPa and95 MPa, the translational vibration amplitude ratio is 3.33 and axial vibration amplitude ratio is 2.08. It indicates that as the rock compressivestrength increases, the growth of the cutterhead’s vibration amplitude increase accelerated, rather than proportional increases;③ The vibration decreases along with the cutter speed becomes larger and the system becomes stabilized when the cutterhead speedturns into 4r/min. The cutter head speed clearly affects torsional, lateral and longitudinal vibration. The change rate has reached 0.53-0.61. Therefore, TBM should choose the right cutter speed to avoid bearing damage, seal failure and other serious accidents; ④ The translationalvibration of components decreases with the components’ mass increase. It has the greatest impact on the horizontal and verticalvibration of the big ring. The vibration changing rate of the big ring reaches 0.31. The big ring has almost no effect on the axial vibrationand overturn, but the energy consumed on rock cutting will be reduced as the mass increases. Body weight should be chosen reasonablyconsidering vibration,construction economy and internal excitation of parameters. The above conclusions provide a theoretical basis forTBM dynamics optimization design, vibration control and cutterhead architecture design.