Proportion Of Raw Materials Research Articles

(271)合成石綿の原料混合割合(第2報)弗素量の最適範囲について

(271)合成石綿の原料混合割合(第2報)弗素量の最適範囲について

(334)合成石綿の原料混合割合(第1報)塩基原料の最適範囲について

(334)合成石綿の原料混合割合(第1報)塩基原料の最適範囲について

The control and elimination of electrical (Dauphiné) twinning in quartz

Quartz for telecommunication purposes has to be of the highest crystalline quality. A considerable proportion of raw material is rejected on account of electrical twinning. The war-time need for economy of quartz led to an investigation of means of removing this defect. The paper surveys the experimental methods used in exploring the possibilities of untwinning quartz. The basis of these methods is a heat treatment of the quartz plate while subjected to a system of stresses applied to the plate by temperature gradients, pure bending, longitudinal compression or torque. The effect of crystallographic orientation is discussed, and the new physical phenomenon of “piezocrescence” is defined.The paper also describes the practical application of the untwinning techniques to quartz-crystal plates, with particular reference to the requirements of telecommunication. It is shown that the method employing heat treatment with an applied torque may be successfully applied to many important types of quartz crystals including the BT and AT cuts. The proportion of success and the occurrence of quartz showing anomalous behaviour are discussed.

Explosives

Zinc co-doped Mg28Ge10O48:Mn4+ red phosphors are synthesized by a solid-state method. The effects of zinc on the phosphors have been investigated by varying the stoichiometric proportions of raw materials. Zn concentration affects the phosphor crystallinity, morphology, composition and energy structure. We have carried out the X-ray power diffraction (XRD), Field emission scanning electron microscope (FESEM), energy dispersion spectrum (EDS), element mapping, UV–Vis absorption measurement and X-ray photoelectron spectroscopy (XPS). The phosphorescence enhancement centered at around 660 nm is ascribed to 2Eg→4A2g transition of Mn4+. The red emission Intensity of optimized sample is 3.08 and 1.64 times of Zn-free samples and conventional magnesium fluorogermanate phosphors, respectively.