A concentration-dependent decrease in biomass, protein, RNA, DNA, and nutrient (NO3- and PO43-) uptake of Lemna minor and Azolla pinnata by Cr, Ni, and Zn was detected. Cr was found to exert maximum toxicity followed ...A concentration-dependent decrease in biomass, protein, RNA, DNA, and nutrient (NO3- and PO43-) uptake of Lemna minor and Azolla pinnata by Cr, Ni, and Zn was detected. Cr was found to exert maximum toxicity followed by Ni and Zn. Metal uptake was dependent on time and concentration of metal in the external rnedium. Both the macrophytes, however, showed preference for Zn followed by Ni and Cr. The uptake kinetics also revealed a low Vmax and high Km for Cr. L. minor was more effcient in accumulating Zn and Cr than A. pinnata in Ni. Compared to immobilized algae and bacterial capsules the test macrophytes showed a greater efficiency for metal removal展开更多
For the problem of free⁃floating space robot(FFSR)that the motion of manipulator will cause a large disturbance to the attitude of satellite,a path planning method based on hp⁃adaptive Gauss pseudospectral method(hp⁃A...For the problem of free⁃floating space robot(FFSR)that the motion of manipulator will cause a large disturbance to the attitude of satellite,a path planning method based on hp⁃adaptive Gauss pseudospectral method(hp⁃AGPM)is proposed in this paper.In this method,the minimum reaction torque acting on satellite is taken as the objective function,and the number of segments and the order of polynomial in each segment are determined adaptively to improve the accuracy and the efficiency of the solution.At the same time,the theoretical convergence of the designed method is innovatively proved to ensure that the solution of the discretized nonlinear programming(NLP)problem is the optimal solution to the original optimal problem.The simulation results of a planar two degree⁃of⁃freedom(2⁃DOF)space manipulator show that the proposed path planning method is more effective than the resolved acceleration control(RAC)method and the control variable parameterization(CVP)method,and is better than other pseudospectral methods both in computation speed and the number of collocation points.展开更多
文摘A concentration-dependent decrease in biomass, protein, RNA, DNA, and nutrient (NO3- and PO43-) uptake of Lemna minor and Azolla pinnata by Cr, Ni, and Zn was detected. Cr was found to exert maximum toxicity followed by Ni and Zn. Metal uptake was dependent on time and concentration of metal in the external rnedium. Both the macrophytes, however, showed preference for Zn followed by Ni and Cr. The uptake kinetics also revealed a low Vmax and high Km for Cr. L. minor was more effcient in accumulating Zn and Cr than A. pinnata in Ni. Compared to immobilized algae and bacterial capsules the test macrophytes showed a greater efficiency for metal removal
文摘For the problem of free⁃floating space robot(FFSR)that the motion of manipulator will cause a large disturbance to the attitude of satellite,a path planning method based on hp⁃adaptive Gauss pseudospectral method(hp⁃AGPM)is proposed in this paper.In this method,the minimum reaction torque acting on satellite is taken as the objective function,and the number of segments and the order of polynomial in each segment are determined adaptively to improve the accuracy and the efficiency of the solution.At the same time,the theoretical convergence of the designed method is innovatively proved to ensure that the solution of the discretized nonlinear programming(NLP)problem is the optimal solution to the original optimal problem.The simulation results of a planar two degree⁃of⁃freedom(2⁃DOF)space manipulator show that the proposed path planning method is more effective than the resolved acceleration control(RAC)method and the control variable parameterization(CVP)method,and is better than other pseudospectral methods both in computation speed and the number of collocation points.
