Silicon Dioxide Thin Films Prepared by Thermal Decomposition of Silicon Tetraacetate

Abstract

By assuming the existence of (quasi)-linear Regge trajectories for 25-plet mesons in the low-energy region, we derive a new, 14th power, meson mass relation. This relation may be reduced to a quadratic Gell-Mann-Okubo-type formula by fitting the values of the Regge slopes of these (quasi)-linear trajectories. Such a formula holds with an accuracy of ∼2% for vector mesons, and also suggests that the quantum number I (J P ) = 1 2 (2 + ) should be assigned to both the B J (5732) and B sJ (5850) mesons discovered recently. We also discuss reasons for the failure of group theory to produce correct mass relations for heavy quarkonia. § + Here, we speak of the linear spectrum over the multiplet quantum numbers, taking proper account of degeneracy, not (directly) making use of linear Regge trajectories.* Here η stands for the masses of both isovector and isoscalar nn states which coincide on a naive quark model level.Since these designations apply to all spin states, vector mesons will be confusingly labelled as η's. We ask the reader to bear with us in this in the interest of minimizing notation.

Silica Nanotubes by Templated Thermolysis of Silicon Tetraacetate

“…We used silicon tetraacetate (SiAc 4 ), which decomposes into silica and acetic anhydride between 160 and 170 °C, as the silicon precursor in the synthesis of SNTs inside the pores of self-ordered nanoporous anodic aluminum oxide (AAO) hard templates prepared by two-step anodization. , While hydrolytic cross-linking of silica precursors is a delicate process sensitively depending on the conditions applied, thermolysis leads to complete conversion of the precursor within a well-defined temperature range. Thin silica films on smooth substrates obtained by thermolysis of Si(Ac) 4 showed, as compared to silica films obtained by hydrolytic sol–gel chemistry, significantly enhanced dynamic hardness . As hydrolysis of SiAc 4 yields silica too, it is not necessary to work under dry conditions.…”

“…Thin silica films on smooth substrates obtained by thermolysis of Si(Ac) 4 showed, as compared to silica films obtained by hydrolytic solÀgel chemistry, significantly enhanced dynamic hardness. 13 As hydrolysis of SiAc 4 yields silica too, it is not necessary to work under dry conditions. As in previous synthetic approaches to mesoporous silica nanorods based on hydrolytic solÀgel chemistry under acidic conditions, 14,15 an amphiphilic block copolymer (BCP), polystyrene-block-poly (ethylene oxide) (PS-b-PEO; M n (PS) = 32.0 kg/mol, M n (PEO) = 11.0 kg/mol; polydispersity index =1.06) served as a structure-directing soft template.…”