Based on the theory of polarization filtering and the merits of interference suppressions when adopting oblique projections, a novel polarization filtering algorithm is proposed in this paper. The proposed method can effectively separate the target signal and interference without additional transformation and compensation processing, and the target does not suffer distortions after separation. The suggested scheme is still valid when the target and interference hold the same polarized angle but different phase difference in polarized angle. We extend the application to the scope of known target polarization but unknown interference polarization, finding that the interference is restrained and the amplitude/phase of the target are both totally kept. Theoretic analysis and mathematical deduction show that the proposed scheme is a valid and simple implementation. Simulation results also demonstrate that the suggested method can obtain better filtering performance than the conventional polarization filtering (CPF) and the null-phase-shift polarization filtering (NPSPF). It is proved that the proposed OPPF is an extension to the CPF and the NPSPF, and it develops the theory of polarization filtering effectively.

In this study, first-principles calculations were utilized to investigate the lattice constants, elastic constants, and mechanical properties of gold–copper (Au–Cu) intermetallic compounds (IMCs), including AuCu3, AuCu, and Au3Cu. We also verified the direction dependence of the Young’s modulus, shear modulus, and Poisson’s ratio of the compounds. The calculated lattice parameters agreed with the experimental data, and the single-crystal elastic constants, elastic modulus E, shear modulus G, bulk modulus B, and Poisson’s ratio ν were calculated. For the Young’s and shear moduli, AuCu3 showed the highest anisotropy, followed by AuCu and Au3Cu. The Poisson’s ratios of AuCu3 and Au3Cu crystals were isotropic on (100) and (111) crystal planes and anisotropic on the (110) crystal plane. However, the Poisson’s ratio of the AuCu crystal was anisotropic on (100) and (111) crystal planes and isotropic on the (110) crystal plane.

In this paper, comprehensive remarks are given that focus on the main fabrications and wide applications of helical long-period fiber gratings (HLPGs). Firstly, the techniques of fabricating HLPGs by CO2 laser, hydrogen–oxygen flame heating, and arc discharge are summarized. Furthermore, the applications of HLPGs are investigated, i.e., orbital angular momentum (OAM) mode converters, all-fiber band-rejection filters, and sensors for measuring physical perturbation of torsion, strain, temperature, curvature, and surrounding refractive index (SRI). Furthermore, several long-period fiber gratings (LPFGs) of near-HLPG structures with periodic refractive index change along the azimuthal direction are introduced. Lastly, the prospects and key challenges for HLPGs are discussed.

Full intermetallic compound (IMC) solder joints present fascinating advantages in high-temperature applications. In this study, the mechanical properties and elastic anisotropy of η’-Cu6Sn5 and Cu3Sn intermetallic compounds were investigated using first-principles calculations. The values of single-crystal elastic constants, the elastic (E), shear (G), and bulk (B) moduli, and Poisson’s ratio (ν) were identified. In addition, the two values of G/B and ν indicated that the two IMCs were ductile materials. The elastic anisotropy of η’-Cu6Sn5 was found to be higher than Cu3Sn by calculating the universal anisotropic index. Furthermore, an interesting discovery was that the above two types of monocrystalline IMC exhibited mechanical anisotropic behavior. Specifically, the anisotropic degree of E and B complied with the following relationship: η’-Cu6Sn5 > Cu3Sn; however, the relationship was Cu3Sn > η’-Cu6Sn5 for the G. It is noted that the anisotropic degree of E and G was similar for the two IMCs. In addition, the anisotropy of the B was higher than the G and E, respectively, for η’-Cu6Sn5; however, in the case of Cu3Sn, the anisotropic degree of B, G, and E was similar.

In this paper, an improved algorithm for prefiltering two-dimensional polygons is presented. The part of the polygon within the mask of a filter is decomposed into basic component regions whose parameters can be easily computed. Given the parameters, the integral of the filter over the basic component region can be looked up from a table or even be computed with a closed-form solution. The integral or its negative is then added to the accumulation buffer of the pixel according to whether the pixel center is outside the component region or not. After travelling all polygon edges, the accumulation buffers are shifted by integers so that they are all between 0 and 1. In this way, the expensive clipping of the polygons against the filter mask becomes unnecessary.