Structural Parameter Of Scissor-Type Lifting Platform And Its Scissor Arm Optimization
In this paper,the structural feature of scissor-type lifting platform is introduced,and its structural parameters is analyzed.By using finite element software ANSYS,the scissor arm of scissor-type lifting platform is optimized,and the most reasonable dimension is got.On the premise of meeting engineering requirement,the utilization ratio of material is improved.
We give a brief introduction to the study of the algebraic structures -- and their geometrical interpretations -- which arise in the BRST construction of a conformal string background. Starting from the chiral algebra $\cA$ of a string background, we consider a number of elementary but universal operations on the chiral algebra. From these operations we deduce a certain fundamental odd Poisson structure, known as a Gerstenhaber algebra, on the BRST cohomology of $\cA$. For the 2D string background, the correponding G-algebra can be partially described in term of a geometrical G-algebra of the affine plane $\bC^2$. This paper will appear in the proceedings of {\it Strings 95}.