Carbon fiber is mainly distributed in the shape of short fibers and unidirectional fibers as the reinforcing phase in metal matrix composites, and it is seldom studied as woven-cloth shaped to reinforce the matrix. In this paper, the pretreatment and the surface metallization of the woven carbon fiber were studied. Besides, the casting experiment without external pressure was carried out under the application of magnetic field. The result shows that when burning about 45mins at 500°C in the atmospheric environment, the pretreatment can achieve the best result according to differential thermal analysis and weight-time variation curve. Meanwhile the surface wettability between the carbon fiber and the matrix is greatly improved after the surface treatment and at the same time the reaction between the carbon fiber and molten aluminium alloy matrix is necessarily avoided, and it can consequently achieve an excellent bonding between the woven carbon fiber and aluminium alloy matrix. The application of magnetic field also provides magnetic force to promote the penetration of the molten matrix into the carbon fiber bundles.

Bivariate Fourier series have many benefits in limited-area modeling (LAM), weather forecasting, and meteorological data analysis. However, atmospheric data are not spatially periodic on the LAM domain (''window''), which can be normalized to the unit square (x, y) 2 [0, 1] 5 [0, 1] by rescaling the coordinates. Most Fourier LAM meteorology has employed rather low-order methods that have been quite successful in spite of Gibbs phenomenon at the boundaries of the artificial periodicity window. In this article, the authors explain why. Because data near the boundary between the high-resolution LAM window and the low-resolution global model are necessarily suspect, corrupted by the discontinuity in resolution, meteorologists routinely ignore LAM results in a buffer strip of nondimensional width D, and analyze only the Fourier sums in the smaller domain (x, y) 2 [D, 1 2 D] 5 [D, 1 2 D]. It is shown that the error in a one-dimensional Fourier series with N terms or in a two-dimensional series with N 2 terms, is smaller by a factor of N on a boundary-buffer-discarded domain than on the full unit square. A variety of procedures for raising the order of Fourier series convergence are described, and it is explained how the deletion of the boundary strip greatly simplifies and improves these enhancements. The prime exemplar is solving the Poisson equation with homogeneous boundary conditions by sine series, but the authors also discuss the Laplace equation with inhomogeneous boundary conditions.

A bulk casting ingot (Ø70 × 150mm) of CoCrFeNiTi0.5 high entropy alloy was prepared by vacuum medium frequency induction melting. The samples from the ingot were aged for 12h in the temperature range of 900-1100°C and then quenched in water to investigate the effect of aging temperature on the microstructure and hardness of CoCrFeNiTi0.5 alloy. The crystalline structure of as-cast CoCrFeNiTi0.5 alloy consisted of the principal face-centered cubic (FCC) dendrite phase plus (Ni, Ti)-rich R phase, (Fe, Cr)-rich σ phase, (Co, Ti)-rich Laves phase within the inter-dendrite area. The dendrite contained approximately equivalent amount of Co, Cr, Fe, Ni and a smaller amount of Ti element. After aging treatment in the temperature range of 900-1000°C, the (Co, Ti)-rich phase disappeared while the amount of (Ni, Ti)-rich phase and (Fe, Cr)-rich phase increased. But the volume fraction of FCC dendrite phase increased and the intermetallic phases decreased after aging at 1100°C. The micro-hardness and the macro-hardness of the as-cast CoCrFeNiTi0.5 alloy were HV616.8 and HRC52, respectively. After heat treatment at 1000°C, the micro-hardness and macro-hardness decreased from HV616.8 to HV386.8 and from HRC52 to HRC42.7, respectively.