This paper considers the geometric design of crab-like walkers and climbers, without decoupling leg design from overall machine design. Crab-like machines represent an important sub-class of multi-legged robots, bein...This paper considers the geometric design of crab-like walkers and climbers, without decoupling leg design from overall machine design. Crab-like machines represent an important sub-class of multi-legged robots, being particularly well suited to crossing difficult terrains. Firstly, the kinematic configurations and constraints are described, which determine the machine’s kinematic characteristics. The influence of the design parameters on the kinematic workspace is discussed. Finally, a two stage design methodology is presented, comprising kinematic design and design optimisation, the latter being based on the use of design maps rather than numerical optimisation. The performance measures considered during design optimisation include kinematic, static and quasi-static measures.展开更多
A theoretical design is presented for a 1 × M wavelength-selective switch(WSS) that routes any one of N incoming wavelength signals to any one of M output ports. This planar on-chip device comprises of a 1 ×...A theoretical design is presented for a 1 × M wavelength-selective switch(WSS) that routes any one of N incoming wavelength signals to any one of M output ports. This planar on-chip device comprises of a 1 × N demultiplexer, a group of N switching "trees" actuated by electro-optical or thermo-optical means, and an M-fold set of N × 1multiplexers. Trees utilize 1 × 2 switches. The WSS insertion loss is proportional to [log_2(M+N +1)]. Along with cross talk from trees, cross talk is present at each cross-illuminated waveguide intersection within the WSS, and there are at most N-1 such crossings per path. These loss and cross talk properties will likely place a practical limit of N=M=16 upon the WSS size. By constraining the 1 × 2 switching energy to^1 f J∕bit, we find that resonant, narrowband 1 × 2 switches are required. The 1 × 2 devices proposed here are nanobeam Mach–Zehnders and asymmetric contra-directional couplers with grating assistance.展开更多
Atrazine, a widely used herbicide, is increasing the agricultural production effectively, while also causing great environmental concern. Efficient atrazine-degrading bacterium is necessary to removal atrazine rapidly...Atrazine, a widely used herbicide, is increasing the agricultural production effectively, while also causing great environmental concern. Efficient atrazine-degrading bacterium is necessary to removal atrazine rapidly to keep a safe environment. In the present study, a new atrazine-degrading strain ZXY-1, identified as Pseudomonas, was isolated. This new isolated strain has a strong ability to biodegrade atrazine with a high efficiency of 9.09 mg/L/hr.Temperature, p H, inoculum size and initial atrazine concentration were examined to further optimize the degradation of atrazine, and the synthetic effect of these factors were investigated by the response surface methodology. With a high quadratic polynomial mathematical model（R^2= 0.9821） being obtained, the highest biodegradation efficiency of 19.03 mg/L/hr was reached compared to previous reports under the optimal conditions（30.71°C, pH 7.14, 4.23%（V/V） inoculum size and 157.1 mg/L initial atrazine concentration）.Overall, this study provided an efficient bacterium and approach that could be potentially useful for the bioremediation of wastewater containing atrazine.展开更多
文摘This paper considers the geometric design of crab-like walkers and climbers, without decoupling leg design from overall machine design. Crab-like machines represent an important sub-class of multi-legged robots, being particularly well suited to crossing difficult terrains. Firstly, the kinematic configurations and constraints are described, which determine the machine’s kinematic characteristics. The influence of the design parameters on the kinematic workspace is discussed. Finally, a two stage design methodology is presented, comprising kinematic design and design optimisation, the latter being based on the use of design maps rather than numerical optimisation. The performance measures considered during design optimisation include kinematic, static and quasi-static measures.
基金Air Force Office of Scientific Research(AFOSR)(FA9550-14-1-0196)
文摘A theoretical design is presented for a 1 × M wavelength-selective switch(WSS) that routes any one of N incoming wavelength signals to any one of M output ports. This planar on-chip device comprises of a 1 × N demultiplexer, a group of N switching "trees" actuated by electro-optical or thermo-optical means, and an M-fold set of N × 1multiplexers. Trees utilize 1 × 2 switches. The WSS insertion loss is proportional to [log_2(M+N +1)]. Along with cross talk from trees, cross talk is present at each cross-illuminated waveguide intersection within the WSS, and there are at most N-1 such crossings per path. These loss and cross talk properties will likely place a practical limit of N=M=16 upon the WSS size. By constraining the 1 × 2 switching energy to^1 f J∕bit, we find that resonant, narrowband 1 × 2 switches are required. The 1 × 2 devices proposed here are nanobeam Mach–Zehnders and asymmetric contra-directional couplers with grating assistance.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(No.2012ZX07212001)the National Natural Science Foundation of China(No.31570505)the State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(No.2014TS05)
文摘Atrazine, a widely used herbicide, is increasing the agricultural production effectively, while also causing great environmental concern. Efficient atrazine-degrading bacterium is necessary to removal atrazine rapidly to keep a safe environment. In the present study, a new atrazine-degrading strain ZXY-1, identified as Pseudomonas, was isolated. This new isolated strain has a strong ability to biodegrade atrazine with a high efficiency of 9.09 mg/L/hr.Temperature, p H, inoculum size and initial atrazine concentration were examined to further optimize the degradation of atrazine, and the synthetic effect of these factors were investigated by the response surface methodology. With a high quadratic polynomial mathematical model（R^2= 0.9821） being obtained, the highest biodegradation efficiency of 19.03 mg/L/hr was reached compared to previous reports under the optimal conditions（30.71°C, pH 7.14, 4.23%（V/V） inoculum size and 157.1 mg/L initial atrazine concentration）.Overall, this study provided an efficient bacterium and approach that could be potentially useful for the bioremediation of wastewater containing atrazine.
