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931.
Velocity analysis of mechanisms with ball joints 总被引:1,自引:0,他引:1
A procedure is developed for analyzing velocities in spatial mechanisms with ball joints has been designed for practical computerization. The correspondence between the calculated velocities in a ball joint and the time changes of the physical displacements is clarified. The methodology is demonstrated using the RSPC mechanism which has seen commercial application as a washing-machine agitator mechanism. 相似文献
932.
933.
Analyses for the metals Cd, Pd and Cu in the estuary and bay of the Scine have been made. The site was chosen because of the very high tides, which produce considerable water displacement. For the purpose of analysis the metals have been divided into three categories: free metals, metals forming complexes that are unstable at low pH, and metals forming stable complexes that are destroyed in an acidic medium by ultraviolet radiation. The special properties of copper have been used to establish a “complexing capacity” of the different water samples studied. By making the simple hypothesis of the existence of an equilibrium of the type Cu + L CuL, where L represents the ligand, the total ligand concentration, as well as the stability constants of the CuL complexes, has been determined. These results are presented and discussed. 相似文献
934.
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939.
Herbert Fischer 《Computational Optimization and Applications》1992,1(3):327-344
This paper is concerned with automatic differentiation methods for computing the reduced gradient M
t
G and the reduced Hessian matrix M
t
HM. Hereby G is the gradient and H is the Hessian matrix of a real function F of n variables, and M is a matrix with n rows and k columns where kn. The reduced quantities are of particular interest in constrained optimization with objective function F. Two automatic differentiation methods are described, a standard method that produces G and H as intermediate results, and an economical method that takes a shortcut directly to the reduced quantites. The two methods are compared on the basis of the reqired computing time and storage. It is shown that the costs for the economical method are less than (k
2+3k+2)/(n
2+3n+2) times the expenses for the standard method. 相似文献
940.