A Practical Monte Carlo Sampling Library is described. The library provides pesudorandom number generators using the best algorithms, excellent random variable generators of many important probability distributions such as spatial position, energy and motion direction distributions often used in particle transport problems. In addition a special test system for sampling library is designed and applied. The library runs on PC/386 (486). Its installation and usage are very easy. It can be applied in various fields and easy portable.

A Monte Carlo simulation for low energy electrons scattering in the sample is presented in this paper. Since the particular features of the physical assumptions and the reaction mech anism, a method which combine the next-event estimator with the last-event estimator is employed. The results are satisfactory.

In this paper, The statistical laws satisfied by the random force of the Langevin equation in physics are discussed.The Monte-Carlo method is used to simulate the motion of Browian particles in the ha ornic oscillator potential with a computer germinated the Gaussian random numbers.The variation of the solutions of the Langevin equation with time step is studied. A foundation of the numerical calculation for such a problem is provided.

General forms of Langevin equation are related briefly; Some basic steps solving this kind of equation are described; Two examples are given; Some quastions are discussed.