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Influence of hexapod robot foot shape on sinking considering multibody dynamics
Gang He,Zhaoyuan Cao,Qian Li,Denglin Zhu,Ji Aimin 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.9
Hexapod robots have attracted attention for their excellent terrain adaptabilities. When a robot walks on soft soil, dynamic subsidence and slippage greatly reduce its walking performance. The influence of foot’s shape is usually ignored or simply studied without considering the multibody dynamics of the robot. This study is focused on the influence of the foot shape on the walking performance of a robot by coupling the sinkage with multibody dynamics. A composite contact model based on the Bekker, spring-damping, and Janosi– Hanamoto models was used to model the interaction of the robot and soft soil. Non-uniform rational B-spline (NURBS) surface and mesh were used to describe the geometries of foot and soft soil, respectively. The influences of three foot shapes on the sinkage and walking stability of the robot were analyzed by comparsion. The improved X-shaped foot reduced the robot’s sinkage and improved its walking stability.
Gang He,Yanna Zhu,Guisheng Zhang,Guotong Qiao 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.12
Security is an important problem in wireless sensor networks. Intrusion detection system is one of the most common methods of network security, for which more and more people have shown solicitude. In this paper, a dynamic random password authentication (DRPA) method is proposed for the identity authentication of communication nodes, which can detect and prevent malicious behavior at each stage of the network operation. This paper introduces the method of automatic generation of random passwords. When a user wants to communicate, the password will be verified to confirm whether it is a normal user or a malicious user. The password’s generation and verification process is very suitable for wireless sensor networks. By using NS2, the simulation experiments are carried out and the results show that this method is superior to the other methods.
The Molecular Characterization of Serogroup C Neisseria meningitidis Strains Circulating in Beijing
Tie-gang Zhang,Jing-guo He,Xiong He,Li-Juan Chen,Zhu-jun Shao,Mei-ping Sun 한국미생물학회 2006 The journal of microbiology Vol.44 No.6
The aim of this study was to characterize the molecular features of serogroup C Neisseria meningitidis strains circulating in Beijing, China. Twenty out of 23 strains belonged to ST 4821. The causative serosubtype for meningococcal meningitis was P1.12-1,16-8. All of the strains expressed class 3 PorB protein. Among the five pulsed-field gel electrophoresis patterns observed, pattern III predominated.
Laboratory Confirmation of A Suspicious Meningococcal Meningitis Death Case
Tie-gang Zhang,Li-juan Chen,Jie Yang,Zhu-jun Shao,Xiong He,Jing-guo He,Ming Luo,Mei-ping Sun 한국미생물학회 2006 The journal of microbiology Vol.44 No.4
A suspicious meningococcal meningitis death case was reported to the Beijing CDC. The blood specimen was analyzed via multi-PCR and MLST. 6 isolates from close contacts were analyzed via PFGE and MLST. According to the results of the above analyses, the cause of this case was identified as a serogroup A Neisseria meningitidis, which, in terms of sequence typing, belonged the ST7 group.
The Molecular Characterization of Serogroup C Neisseria meningitidis Strains Circulating in Beijing
Zhang, Tie-Gang,He, Jing-Guo,He, Xiong,Chen, Li-Juan,Shao, Zhu-Jun,Sun, Mei-Ping The Microbiological Society of Korea 2006 The journal of microbiology Vol.44 No.6
The aim of this study was to characterize the molecular features of serogroup C Neisseria meningitidis strains circulating in Beijing, China. Twenty out of 23 strains belonged to ST 4821. The causative serosubtype for meningococcal meningitis was P1.12-1,16-8. All of the strains expressed class 3 PorB protein. Among the five pulsed-field gel electrophoresis patterns observed, pattern III predominated.
Laboratory Confirmation of A Suspicious Meningococcal Meningitis Death Case
Zhang Tie-Gang,He Xiong,Chen Li-Juan,He Jing-Guo,Luo Ming,Yang Jie,Shao Zhu-Jun,Sun Mei-Ping The Microbiological Society of Korea 2006 The journal of microbiology Vol.44 No.4
A suspicious meningococcal meningitis death case was reported to the Beijing CDC. The blood specimen was analyzed via multi-PCR and MLST. 6 isolates from close contacts were analyzed via PFGE and MLST. According to the results of the above analyses, the cause of this case was identified as a serogroup A Neisseria meningitidis, which, in terms of sequence typing, belonged the ST7 group.
He, Mingrui,Kim, Jihun,Suryawanshi, M.P.,Ghorpade, U.V.,Gang, Myengil,Suryawanshi, U.P.,Kim, Jin Hyeok Elsevier 2018 Materials letters Vol.211 No.-
<P><B>Abstract</B></P> <P>Cu<SUB>2</SUB>SnS<SUB>3</SUB> (CTS) thin films have been investigated extensively as an absorber layer for photovoltaic applications owing to the use of low-cost and earth-abundant materials. However, the performance of CTS solar cells still suffers from voltage deficit, resulting in a low value of open-circuit voltage (<I>V</I> <SUB>oc</SUB>). In this study, we introduce a Ge layer into CTS materials using Ge metal target asa doping source. Subsequently, the sputtered Cu/Ge/Sn precursors are sulfurized under sulfur vapor ambient to form a Cu<SUB>2</SUB>(Sn,Ge)S<SUB>3</SUB> (CTGS) thin film. Meanwhile, we also fabricate a CTS solar cell under the same experimental conditions as compared with CTGS solar cell. The Ge layer of thickness approximately 20nm enhanced the efficiency from 0.45% (CTS) to 3.05% (CTGS), whereas the improvement in performance was limited for Ge layer of thickness more than 20nm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CTGS thin film solar cell exhibited the highest efficiency of 3.05%. </LI> <LI> The Ge layer of thickness approximately 20nm is optimized doping concentration for CTGS thin film solar cell. </LI> <LI> Ge doping approach can boost the value of <I>V</I> <SUB>oc</SUB> significantly. </LI> </UL> </P>
Research on the Oxidation-Protective Coatings for Carbon/Carbon Composites
He-Jun Li,Qian-Gang Fu,Jian-Feng Huang,Xie-Rong Zeng,Ke-Zhi Li 한국탄소학회 2005 Carbon Letters Vol.6 No.2
Anti-oxidation coatings are the key technique for carbon/carbon (C/C) composites used as the thermal structural materials. The microstructure and oxidation behavior of several kinds of high-performance ceramic coatings for C/C composites prepared in Northwestern Polytechnical University were introduced in this paper. It showed that the ceramic coatings such as SiC, Si-MoSi2, SiC-MoSi2, Al2O3-mullite-SiC and SiC/yttrium silicate/glass coatings possessed excellent oxidation resistance at high temperatures, and some of these coatings were characterized with excellent thermal shock resistance. The SiC-MoSi2 coating system has the best oxidation protective property, which can effectively protect C/C composites from oxidation up to 1973 K. In addition, the protection and failure reasons of some coatings at high temperature were also provided.
Wind Power Dispatching under Grid Transmission Constraints
He, Shi-En,Zhang, Bo-Lin,Cui, Gang,Li, Xiao-Hu The Korean Institute of Electrical Engineers 2011 The Journal of International Council on Electrical Vol.1 No.1
In recent years, wind power penetration into the grid increased rapidly in Jiuquan, supported by the Provincial government to "establish a 'Hexi Wind Power Corridor' and to rebuild a Western 'Terrestrial Three Gorges Dam'". Jiuquan, as part of Silk Road along Hexi Corridor in China's Gansu Province, is far away from any load centers. Wind farms in this region are connected to 110 kV or above transmission network with a weak grid configuration and the transmission passage is the bottleneck of wind power delivery. This paper studies the integration of wind power into Jiayuguan-Jiuquan (Jia-Jiu) Grid focusing on the impact on Gansu Provincial Power Grid operation. By using power system analysis software package and the latest wind turbine models the transient stability is analyzed and a Special Protection Scheme (SPS) is configured to improve the wind power delivery ability. The results show that the SPS is effective. Discussions and suggestions are also included.