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The load distribution on rolling elements is one of the most important operating characteristics of a bearing. In this paper, a mathematical model for the calculation of radial load distribution on ball and roller bearings with positive, negative and zero clearance is derived and presented. A predeformation model for bearings with nonzero clearance is proposed. Based on contact deformation and Hertz elastic contact theory, inner raceway contact force is calculated and is used for static equilibrium equation, which could avoid calculate the series of stiffness of inner and outer raceway contact deformation. The static equilibrium equation is solved by a loop which aims to delete inactive rolling elements. The obtained results are compared with results of Harris and Stribeck method and found to be in close or identical agreement.

The wave-front phase recovery method is a method of numerically calculating the phase distribution of the wave-front by measuring the field intensity distribution of the emission field. Because of its easy operation, high accuracy of inversion and high precision, it has received great attention and extensive application in the free-form surface shape in modern optics detection, telescope primary, secondary mirror misalignment detection and adjustment, beam shaping and other fields. This article briefly describes several different classical methods for restoring the wave-front phase, such as the GS algorithm, HIO algorithm, and PIE algorithm in the iterative method; The transport of intensity equation (TIE)method in the non-iterative method. Then analyzed their respective advantages and disadvantages, at same time put forward personal opinions on the current deficiencies and the future direction of development.

Based on Abaqus/explicit dynamics finite element program, an ax symmetrical numerical model, the infinite fringe condition and friction contact condition were built, and then the surface contact stress condition of the dynamic consolidation was studied. The time-load properties of dynamic consolidation, the spread law of contact pressure for rammer bottom and the friction influence to contact stress between the hammer and foundation were gained. The results indicate that the dynamic consolidation load can be simplified to triangular load with the weight of the hammer itself; the contact stress distribution between the hammer and the foundation is not uniform; and frictionless contact hypothesis can led errors to the simulated result.

Many target-tracking applications require an optical system to acquire the target for tracking and identification. This paper describes a new detecting optical system that can provide automatic flying object detecting, tracking and measuring in visible band. The main feature of the detecting lens system is the combination of diffractive optics with traditional lens design by a technique was invented by Schupmann. Diffractive lens has great potential for developing the larger aperture and lightweight lens. First, the optical system scheme was described. Then the Schupmann achromatic principle with diffractive lens and corrective optics is introduced. According to the technical features and requirements of the optical imaging system for detecting and tracking, we designed a lens system with flat surface Fresnel lens and cancels the optical system chromatic aberration by another flat surface Fresnel lens with effective focal length of 1980mm, an F-Number of F/9.9 and a field of view of 2ωω = 14.2′, spatial resolution of 46 lp/mm and a working wavelength range of 0.6~0.85um. At last, the system is compact and easy to fabricate and assembly, the diffuse spot size and MTF function and other analysis provide good performance.

The light-propagation ability of fiber depends mostly on fiber diameter. Fibers with a diameter below 200 nm have poor capability of exhibiting light coupling and laser radiation. Therefore, we modified nanofibers with a diameter of 150 nm by nanoparticle doping and morphological modification to enhance scattering. A finite-difference time-domain method was used to analyze the coupling of light into fibers and its possible distribution. The simulations demonstrated that single and multiple modes were highly influenced by the diameter values. The results of the study contribute to the realization of random lasers in nanofibers with extremely small diameters.

In all laser pointing systems, boresight and jitter are two fundamental pointing errors arising from vibrations and atmospheric turbulence. The maximum-likelihood estimation 1 advanced by Deva K.borah recently can simultaneously estimate jitter and boresight. Besides some traditional qualities just like high precision and speediness, the maximum-likelihood estimation has a new quality that the performance of this estimator is different when boresight and jitter errors are different. Furthermore, the Monte Carlo simulation results demonstrate that the maximum-likelihood estimation has a higher degree of precision when boresight is bigger than jitter. According to this, a careful analysis is made and some advice is given for the readers who wish to obtain high precise results.