LiNi1-xMxVO4的红外光谱和拉曼光谱研究

The vanadates of LiNi_1-xM_xVO₄(M=Fe,Co,Ni) containing VO₄ tetrahedrons were synthesized by soft chemical method through a new mild liquid route. The samples sintered at 450℃ for 3h and at 650℃ for 3h are named for LT-LiNiVO₄ and for MT-LiNi_1-xM_xVO₄ respectively. All of the products were measured by X-ray diffraction, IR and Raman spectra respectively. In comparison with IR spectra of V₂O₅ and NiO, the LT-LiNiVO₄ has a strong and broad IR absorption band of VO₄ tetrahedrons located at 600～850cm^-1 with three small splitting peaks corresponding to the asymmetry stretching vibrations of V-O bonds. The results of IR and Raman spectra for MT-LiNi_1-xM_xVO₄ show that the cations of Ni²⁺, Co²⁺, Fe²⁺ have the influences on the frequency shifts of the V-O vibrations.     

Central configurations of nested regular tetrahedrons

In this paper, we study the necessary and sufficient conditions about nested regular tetrahedrons, and prove that some nests do not form central configurations, some can. The necessary and sufficient conditions of central configurations are the masses of the inner layer and outer layer must equal, respectively, and the ratios of masses and distances of inner and outer layer must satisfy an equation.     

Diffusion of Anisotropic Colloidal Microparticles Fabricated Using Two-Photon Lithography

Polymeric particles with complex shapes are required for biomedical therapies, colloidal self-assembly, and micro-robotics. It has been challenging to synthesize particles beyond simple shapes (e.g., spheres, cubes) with high structural accuracy using existing methods. Here, a method for fabricating polymeric microparticles of complex 3D shapes is reported using two-photon lithography, and dispersing the particles in an aqueous solution on a glass substrate. The fabrication of polyhedrons (e.g., tetrahedron, pyramid), polypods (e.g., tetrapod, hexapod), and other shapes of 5–10 µm in size is demonstrated. Confocal microscopy is used to track the motion of the sphere, tetrahedron, tetrapod, and screw-shaped particles near the substrate, and determine their translational diffusion coefficients. HYDRO++ is used to simulate the motion of the particles far from the substrate. The influence of particle size and substrate effects on diffusion in the spherical particles is determined and finds that the non-spherical particles have increased hindrance at the substrate compared to the spherical particles.     

正四面体仿射套型九体中心构型(英文)

本文研究R3中一类九体中心构型,该构型由两个正四面体及几何中心带一个质量构成.利用中心构型等价类的性质及分析方法,得到了该构型构成中心构型的充分和必要条件,并且证明了对任意给定的质量比这类中心构型存在且唯一,推广了文献[16]的结论.