Materials Literature
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We report a sharp band observed at 867 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ in polarized Raman scattering from the edge plane of highly oriented pyrolytic graphite (HOPG). Polarization measurements indicates that this band is a vibrational mode with ``out-of-plane'' atomic displacement which is absolutely unexpe…
This paper reviews work on the second-order nonlinear optical properties of chiral thin films and surfaces. In particular, we give an overview of the theoretical formalism and experimental procedures that have been used to describe second-harmonic generation from chiral surfaces or thin films. In addition, we discuss…
The simultaneous removal of a surfactant template and attachment of trialkylsilyl groups has been successfully achieved by treating uncalcined MCM-41 with trialkylchlorosilanes, resulting in the synthesis of mesoporous hydrophobic materials of highly uniform pore structure.
Thermoelectric materials are used in a wide variety of applications related to small-scale solid-state refrigeration or power generation. Over the past 30 years, alloys based on the Bi-Te compounds (refrigeration) [(Bi[sub 1[minus]x]Sb[sub x])[sub 2] (Te[sub 1[minus]x]Se[sub x])[sub 3]] and Si[sub 1[minus]x]Ge[sub x]…
From the BCS theory, we derive an equation which accounts for quantum effects of an electron motion along open Fermi surfaces and determines the upper critical field ${H}_{c2}^{\ensuremath{\perp}}(T)$ perpendicular to the chains of a quasi-one-dimensional conductor. This equation demonstrates two unusual phenomena: (1…
A simple and efficient synthesis and characterization of a series of first generation dendrimers based on cyclophosphazene cores and containing up to 16 peripheral chiral ferrocenyl ligands is described.
Reaction of 1,3,5-tricarboxylatobenzene (trimesic acid) with [Mo2(DAniF)2(MeCN)4][BF4]2 (DAniF = N,N′-di-p-anisylformamidinate) leads to the quantitative formation of a large tetrahedral molecule containing four triply-bridging C6H3(CO2)3 (trimesic acid trianion) groups and six Mo2- (DAniF)2 units; the structure has b…
A novel method for trimethylsylilation of micro- and meso-porous titanosilcates using BSTFA [N,O-bis(trimethylsilyl)trifluoroacetamide] renders Ti-MCM-41 and SiO2/TiO2 aerogels active for olefin epoxidation with aqueous H2O2, and even improves the activity of TS-1.
Nonlinear optical (NLO) donor-acceptor (D-A) chromophores containing a fused terthiophene, namely dithienothiophene (DTT) as electron relay, and various strength acceptors were synthesized to evaluate the relay's role in the solvatochromism as well as in the molecular nonlinearity, µβ(0). Their solvatochromic behavior…
The overall analytical process involves a number of steps:sample collection, transportation and storage, analysis, datacollection, processing and evaluation. Most of these essentialsteps commonly involve the use of polymeric materials in oneform or another. Inert polymers are the usual materials of choicefor sample co…
Cetyltrimethylammonium glycotitanate(IV), glycozirconate(IV) and glyconiobate(V), CTA 1,2 [M(OCH 2 CH 2 ) 3 ] where M=Ti(IV), Zr(IV), Nb(V), have been synthesized under non-aqueous conditions by reacting Na 1,2 [M(OCH 2 CH 2 ) 3 ] with CTACl in ethylene glycol. The glycometallates all have a structure based upon an oc…
We report here on an experimental study of slow thermal relaxation effects from the metastable metallic-ferromagnetic phase to the insulating one in a charge-ordered manganese oxide, ${\mathrm{Pr}}_{0.67}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}.$ The metal-insulator transition is evidenced by an abrupt jump of the resis…
There have been major advances in solid state and materials chemistry in the last two decades and the subject is growing rapidly. In this account, a few of the important aspects of materials chemistry of interest to the author are presented. Accordingly, transition metal oxides, which constitute the most fascinating c…
A novel pillared clay, i.e. pillared montmorillonite with crystallized TiO2, has been developed as a highly active photocatalyst. The TiO2 pillars in pillared montmorillonite were crystallized to anatase by hydrothermal treatment, while the porosity of the pillared clay was retained. The size of the crystallized TiO2…
We examine the reasons for the poor quantitative agreement between the structures predicted from the minimum energy configuration of first principles calculations and those deduced from surface X-ray diffraction experiments for the structure properties of the TiO2(110) surface. In order to confine all numerical approx…
Quaternary organic tetraalkylammonium hydroxide grafted on MCM-41 is a strong Brønsted base catalyst, and represents a useful alternative to soluble bases in reactions such as Knoevenagel condensations, Michael additions and aldol condensations because of their high catalytic activity under mild conditions, and good s…
The upconversion emission intensities of Er3+ ion around 550 and 660 nm in fluorozirconate glasses were measured under 800 nm excitation. Though energy transfer processes played an important role in upconversion mechanism at high concentration of ErF3, those have not been treated quantitatively. The energy transfer ra…
The effects of firing temperature on the crystallinity and the luminescent properties of phosphor have been investigated over the temperature 1000–1800°C range under preparative conditions which do not use any flux such as . The effects of particle shape and size of the ingredient on the phosphor have also been studie…
β-Zn(dca)2 and 0.12% Co(II) doped β-Zn(dca)2 contain tetrahedrally coordinated metal ions within a corrugated sheet network structure [dca = dicyanamide, N(CN)2–], β-Co(dca)2 is a spin-canted antiferromagnet (TN = 9 K), while the rutile-like octahedral α-form is a ferromagnet.
Sealed alkaline solid polymer electrolyte nickel/metal hydride laboratory cells have been constructed and tested to evaluate their properties. Studies of the cycle life, self‐discharge, and behavior of cells at different temperatures were carried out. The first results on the electrochemical behavior of an alkaline so…