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The high strength and high hard metal materials such as nickel-based superalloy have been widely used because of their excellent properties. If the gradient nanostructures are prepared on their surfaces, their properties will be further improved and their application will be expanded. In this paper, a coupled mechanical ultrasonic-electric pulse (CMUEP) treatment method is presented and its special pulse power source with high instantaneous energy density is developed. The power supply includes main circuit, gate turn-off thyristor (GTO) control circuit, switch control circuit, display circuit, etc. The CMUEP treatment of nickel-based superalloy is carried out by using this power source. The results show that grains with the average diameter of 25.8nm are prepared on Inconel 718 surface, which can further improve the properties of the high strength and high hard metal materials and broaden their application.

In this paper, researching the correlation property of congenetic subband coefficients of Nonsubsampled Contourlet Transform (NSCT), and proposing a new adaptive denoising theory. This theory combines the excellent shift-invariant of NSCT with the correlation property of congenetic subband coefficients in image denoising. The correlation property contains the entire relational correlation value of the congenetic subband coefficients, and the grey correlation value in single coefficient of the congenetic subband coefficients of the NSCT. According to the correlation property of congenetic subband coefficients, the new algorithm can automatically identify the strong edges, weak edges and noise in the noisy image, and then it can filter the noise and preserve the strong edges and weak edges at certain degree. The experiment results are provided to compare with the elegant non-local means method, which show that the theory proposed in this paper has good effect.

A new method is presented in this article to determine loads on all rollers in a cylindrical roller bearing. By introducing a pair of nonlinear springs for contact of each roller with its inner and outer races, the equations of equilibrium of the multi-component system are established by means of the virtual work principle. A set of linear complementary equations are deduced and solved using the Lemke algorithm for gaps and contact forces between all potentially engaged components. An iterative scheme is employed to effectively deal with the nonlinearity of the Hertzian contact between non-conforming bodies. Numerical results for a 19-roller cylindrical bearing, having various combinations of roller sizes, show that the proposed method is convergent and accurate. With this method, effects of uneven roller sizes caused by manufacturing errors, on load distributions can be accurately and efficiently determined. The proposed method can be extended to deal with other types of manufacturing errors such as uneven roller angular spacing, eccentricity, ovality, friction, etc., which are of significant interest to the bearing manufacturers.

There are always some differences in the diameters of the rolling elements that are less than manufacturing tolerance, which are known as off-sized defects. These diameter differences of the rolling elements assumed to be with identical size in the traditional bearing analysis affect the load performance of the bearing greatly and make the evaluation of the load distribution in the bearing difficult. In this study, a static model was developed to investigate the effects of diameter differences among cylindrical rollers on the load performance in a bearing. In the model, the diameter and order of each roller were defined arbitrarily. Contact judgments between all the rollers and the raceways were done constantly in the solution process, so that compatibility of deformation of the rollers and raceways need not be considered, which was different from other traditional methods. The effects of roller off size and its arrayed order in the bearing on the load distribution were analyzed. It was found that the effect of one off-sized roller on the load distribution was serious. Also, equal space or ordinal array of the multiple or full off-sized rollers was much better than random array. Furthermore, the relative diameter of the rollers determined the load distribution in the bearing. This article can help to further study the dynamic performance of the bearing with the off-sized cylindrical roller in the future.