springs are the  mechanical parts which have many application in industries. static and dynamic forces cause relaxation in these parts so that they lose some of their free length and reaction force. springs constant are very important in airplane and vailway industry since constant and variable forces are applied to them in period time, therefore it is necessary to avoid decreasing in spring co...

We investigate the problem of determining planar curves that describe ramps where a particle mass \begin{document}$ m $\end{document} moves with constant-speed when is subject to action friction force and whose magnitude id="M2">\begin{document}$ F(r) depends only on distance id="M3">\begin{document}$ r f...

We present a quantitative analysis of recent data on the kinetics of ATP hydrolysis, which has presented a puzzle regarding the load dependence of the Michaelis constant. Within the framework of coarse grained two-state ratchet models, our analysis not only explains the puzzling data, but provides a modified Michaelis law, which could be useful as a guide for future experiments.

The chemical composition of small organic molecules is often very similar to amino acid side chains or the bases in nucleic acids, and hence there is no a priori reason why a molecular mechanics force field could not describe both organic liquids and biomolecules with a single parameter set. Here, we devise a benchmark for force fields in order to test the ability of existing force fields to re...

A patch representation differing from the traditional treatments in the boundary element method (BEM) is presented, which we call the constant "node patch" method. Its application to solving the Poisson-Boltzmann equation (PBE) demonstrates considerable improvement in speed compared with the constant element and linear element methods. In addition, for the node-based BEMs, we propose an efficie...

Understanding the nanoscale electrostatic interaction between a conductive atomic force microscopy (AFM) probe and dielectric film is central to operation of various microscopies determination properties film. There no simple analytical description generated in confined probe-sample geometry for neither static nor dynamic AFM modes used measurements. An accurate involved physics obtained only b...