Effect of CsxWO 3 Nanoparticles Content and Atomic Ratio for Near Infrared Cut-off Characteristics
In this work, the ceramic nanocomposites films with homogeneous dispersions of tungsten bronze nanoparticles with ternary additive cesium have been prepared by mixing Urethane acrylic/UVcoating binder and dispersed sol depending on the atomic ratio and the particle contents. Furthermore, we are synthesized the CsxWO3 with different annealing at 700, 800, and 900 °C in an N2 gas for 1 hr respectively. The structure and sizes of ceramic particles was observed XRD and PSA spectrometer, the heat-shielding properties of their films were investigated by NIR spectrometer. Synthesized Cs0.33WO3 particles with annealing at 800 °C typically formed hexagonal tungsten bronze structure for good absorption of NIR, size observed as being 30-100 nm and <150 nm. Especially, remarkable absorption of NIR wavelength ranges makes ceramic composite films good candidate for use as a heat shielding window, it clearly shows useful for applications where heat shield is required.
Facile synthesis and structure characterization of hexagonal tungsten bronzes crystals
Abstract A facile molten-salt route was used to synthesize hexagonal Cs 0.33 WO 3 , Rb 0.33 WO 3 and K 0.30 WO 3 crystals. The three isostructural compounds were successfully prepared from the reaction of M x WO 3 powders (M = Cs, Rb, K) in the CsCl/NaCl, RbCl/NaCl and KCl/NaCl fluxes, respectively. The structure determination and refinement, based on single-crystal X-ray diffraction data, are in agreement with previous works, possessing space group P6 3 /mcm. The a and c parameters vary non-linearly with increasing radii of the M + cations (r M ) that is coordinated to twelve oxygen atoms. Both the volumes of unit-cell and WO 6 octahedra vary linearly with r M , which become smaller from Cs 0.33 WO 3 to K 0.30 WO 3 . The distortion of WO 6 octahedra as well as isotropic displacement parameters increases from Cs 0.33 WO 3 to K 0.30 WO 3 . The geometry of the WO 6 octahedron becomes more regular with increasing r M . These structural trends arise from the effective size of the M + cation.
Graphs of polyhedra; polyhedra as graphs
Relations between graph theory and polyhedra are presented in two contexts. In the first, the symbiotic dependence between 3-connected planar graphs and convex polyhedra is described in detail. In the second, a theory of nonconvex polyhedra is based on a graph-theoretic foundation. This approach eliminates the vagueness and inconsistency that pervade much of the literature dealing with polyhedra more general than the convex ones.