Materials Literature
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Abstract A new, generalized, method for measuring the steric size of ligands and substituents has been developed. The method is based on the solid angle concept, the solid angle being generated by the pairwise addition of spheres (atoms). The problem of overlapping spheres (atoms) has been solved analytically and the…
A simple criterion as a first approximation to predict the formation of elementary colloids of implants in SiO 2 glasses by ion implantation has been proposed. The criterion predicts that colloid formation occurs when free energy of formation of oxides of implants is greater than that of SiO 2 at ∼3000 K, which corres…
Studies of imprint properties have been carried out by electrical evaluation with pulse switching response and circuit modeling on sol-gel lead zirconate titanate (PZT) ferroelectric thin-film capacitors. The imprint properties were evaluated by measuring the switched and nonswitched charges after three different oper…
Durch quantitative Cyanethylierung von Polyaminen kombiniert mit katalytischer Hydrierung der gebildeten Polynitrile sind Poly(trimethylenimin)‐Kaskadenmoleküle in hohen Ausbeuten und hohen Reinheiten zugänglich. Ausgehend von Ammoniak wurden mit dieser Reaktionssequenz hochsymmetrische Dendrimere bis zur fünften Gene…
(Ba 0.5 Sr 0.5 )TiO 3 thin films (200-300 nm) were deposited on Pt-coated Si substrates by laser ablation at 500 and 650°C. The leakage currents of crystalline films grown at 650°C were found to be higher than those of amorphous films grown at 500°C. The crystalline thin films showed higher surface roughness than the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA two-dimensional polymer formed by TCNE and dirhodium tetra(trifluoroacetate)F. Albert Cotton and Youngmee KimCite this: J. Am. Chem. Soc. 1993, 115, 18, 8511–8512Publication Date (Print):September 1, 1993Publication History Published online1 May 2002Published inissue 1 Sep…
Stoichiometric Bi 4 Ti 3 O 12 thin films were prepared by sol-gel processing. This paper discusses the synthesis of polymerizable solutions containing Bi and Ti, and characterization of the resulting Bi 4 Ti 3 O 12 thin films. The formation of metallic alkoxide and acetate alkoxide are indispensable, soluble precursor…
The dielectric constant and leakage current were studied for SrTiO 3 films thinner than 100 nm, focusing on the influence of the dielectric-electrode interface and the grain boundary. Experimentally, the thickness dependence of the dielectric constant and leakage current was investigated for both epitaxially grown fil…
A neutron-diffraction measurement in the 0--23 A${\mathrm{\r{}}}^{\mathrm{\ensuremath{-}}1}$ inverse space interval was performed on pure amorphous Si. With the structure factor obtained experimentally three-dimensional models were constructed by reverse Monte Carlo simulation for the determination of the atomic struc…
Based on the results of total-energy calculations using the full-potential linear muffin-tin orbital method, the equilibrium ground-state structure is determined in perovskite-type ${\mathrm{KNbO}}_{3}$ and ${\mathrm{KTaO}}_{3}$ complex oxides. The first compound is found to have a ferroelectric zero-temperature groun…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTComplementarity and internal consistency between magnetic and optical properties for the manganese(II) copper(II) heterodinuclear compound [Mn(Me6-[14]ane-N4)Cu(oxpn)](CF3SO3)2 (Me6-[14]ane-N4 = (.+-.)-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane; oxpn = N,N'-…
Pb(Zr, Ti)O 3 thin films of thickness ranging from 55 nm to 625 nm were synthesized on Pt/Ti/SiO 2 /Si substrates using a sol-gel process. The film thickness dependence of both microstructure and electrical properties was investigated. The synthesized films showed columnar structure. The diameter of each column was ar…
Incorporation of polyethylene glycol-derivatized phospholipids into liposomes results in carriers that can enhance the therapeutic efficacy of encapsulated drugs by imparting the ability to evade the reticuloendothelial system and remain in the circulation for prolonged periods. In this study, doxorubicin encapsulated…
Abstract The effect of water vapor and SO2 on the selective reduction of nitric oxide over alumina-supported Ag, In, Ga, Sn, and Zn catalysts has been investigated. Water vapor and SO2 had large effect on the reactivity of propene and on the reduction of NO over those catalysts.
Si-rich SiO 2 films have been prepared by a rf cosputtering method and their photoluminescence, as well as infrared absorption and Raman spectra, has been measured for the as-deposited and annealed films. Photoluminescence spectra very similar to those of porous Si were observed for the sample with a relatively low Si…
Compressive stress is a widespread phenomenon in films subjected to ion beam bombardment. A thermodynamic treatment of materials under a general stress is used to show that preferred orientation will occur as a result of free energy minimization in a biaxial stress field. The equilibrium between structural phases of m…
The largest cluster characterized to date by a crystal structure analysis , [Cu 146 Se 73 (PPh 3 ) 30 ], forms in the reaction of CuCL with Se(SiMe 3 ) 2 in the presence of PPh 3 in THF. The Cu‐Se core of this huge cluster is shielded perfectly by the PPh 3 ligands. In this way, a molecule with a diameter of about 40…
Multilayer composites of a piezoelectric material and a piezomagnetic material can be designed to exhibit magnetoelectric (ME) effect. Such a composite is electrically polarized when it is placed in a magnetic field or is magnetized when an electric field is applied to it. Since the phases have anisotropic properties,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLeptosphaerones A and B, New Cyclohexenones from Leptosphaeria herpotrichoidesWilliam A. Ayer, Türkan Gökdemir, Shichang Miao, and Latchezar S. TrifonovCite this: J. Nat. Prod. 1993, 56, 9, 1647–1650Publication Date (Print):September 1, 1993Publication History Published onli…
Polarized infrared spectroscopy was used to characterize molecular orientation in polyimide films deposited on silicon wafers. The films were constructed from a single polyimide having a rodlike molecular skeleton. The degree of in-plane orientation at the interface with the wafer in the film varied with film thicknes…