Search

This paper proposed a calculation model of transverse Poisson's ratio of continuous fiber reinforced composite, in which the fibers are centrally arranged in a representative volume element. According to the equivalent strain rule of matrix and fiber in fiber direction, the formula of transverse Poisson's ratio was deduced by mathematical method, which shows that the transverse Poisson's ratio of the composite material is associated with the Poisson's ratios and the elastic modulus of fiber and matrix. It was shown by an example that the transverse Poisson's ratio of composite was less than the weighted average number of the Poisson's ratios of fiber and matrix , even less than the matrix Poisson's ratio in a large range. The minimum value indicates that the fibers obviously resist longitudinal deformation under the transverse force.

In this paper, when Reynolds number is within the range of 10000 to 1000000, the horizontal component of the total pressure of flow around flat plate at high angle of attack was regarded as lift of high angle of attack, and the vertical component was regarded as drag of high angle of attack. The horizontal component of total pressure at small angle of attack was regarded as shape drag, and the total drag coefficient at small angle of attack was considered to the sum of the shape drag and frictional drag at zero angle of attack. For the two states of large and small angle of attack, the application scopes of the formulas of lift and drag coefficients were given. Final, the relations of lift and drag coefficients were obtained by eliminating all angles of attack. Research results show that lift - drag curve of small angles of attack is parabola, and the lift - drag curve of high angles of attack is circle.

The calculations of the elastic modulus and the internal stresses of the orthogonal symmetric laminated plates are very difficult, so experimental or numerical simulation methods were used generally. This paper proposed an Equivalent Strain Model, which can greatly simplify the derivation process of the analytical formulas. By the Equivalent Strain Model, the elastic modulus formula of two-layer plate was derived, and the formula shows that the elastic modulus of the laminated plate meets to the mixture rule of the cross-sectional area ratio of each its single-layer plate; Other formulas derived show that the stress within each single-layer plate is proportional to its elastic modulus and the external load stress, and is inversely proportional to the elastic modulus of the laminated plate. The formula of the average shear stress between two single-layer plates also was derived. Recursive method can be used for multilayer plate calculations.

The purpose of this article is to find out the future business models and business model innovation methods of Internet of Things (IoT) industry. Through the analysis of IoT-based logistics information system features, it is clear that IoT-based supply chain integration must be dominated by fourth party logistics (4PL) providers rather than telecoms and technical manufacturers. Two implementation models of IoT-based 4PL are viable. Under the function of more rational policies, many enterprises including logistics providers, logistics management consultants and IT companies would be IoT-based 4PL enterprises, and enhance the logistics management of all society.

This study successfully synthesized manganese-doped calcium zirconate phosphor and manganese-doped strontium zirconate phosphor using the sol-gel method. We employed X-ray powder diffraction and fluorescence spectroscopy to analyze the crystal structure and spectral characteristics of both phosphors. In X-ray powder diffraction analysis, data related to manganese-doped calcium zirconate phosphor and manganese-doped strontium zirconate phosphor were compared using X-ray diffraction comparison software to confirm the crystal structures of both phosphors. The crystal structure of manganese-doped calcium zirconate phosphor was in accordance with orthorhombic perovskites belonging to the Pnma {62} space group. The lattice parameters were a=5.762 Å, b=8.017 Å, and c=5.591 Å; c/a=0.97; volume=258.3 Å3, and density=4.611 g/cm3. The crystal structure of manganese-doped strontium zirconate phosphor conformed to orthorhombic perovskites belonging to the Pnma {62} space group, and the lattice parameters were a=5.818 Å, b=8.204 Å, c=5.797 Å; c/a=0.996; volume=276.7 Å3, and density=5.446 g/cm3. Fluorescence spectroscopy indicated that the primary broadband peak of manganese-doped calcium zirconate phosphor was located at 396.6 nm in the excitation spectrum corresponding to the 4T2(4G)4T1(4P) energy level transition. In the emission spectrum, the primary broadband peak was located at 596.6 nm, corresponding to the 4T2(4D)4T2(4G) energy level transition. For manganese-doped strontium zirconate phosphor, the primary broadband peak was located at 496.6 nm in the excitation spectrum and at 696.6 nm in the emission spectrum, corresponding to the 4T1(4G)4T2(4D) and 4E(4G)4T1(4G) energy level transitions, respectively.