Materials Literature
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Mild anodizing treatment of 304 stainless steel microelectrodes in sodium metasilicate solution reduces the frequency of pit nucleation events markedly when the metal is subsequently exposed to acidic chloride solutions. The same treatment of larger specimens increases the pitting potential substantially. The results…
This paper deals with the synthesis of phthalocyanine complexes, containing four oligo(oxyethylene)-, oxybenzene-, esther of p-oxybenzoic acid or p-oxyazobenzene side chains terminated by a bulky trityl substituent. Their purity was established by column chromatography and by satisfactory elemental analysis. The struc…
Three fullerene derivatives have been employed with amphiphilic block copolymers both as structure-directing agents and doping molecules in one-pot synthesis of self-assembled 2D-hexagonal and cubic porous silica mesostructures, in the form of bulk materials, thick cast films and thin films through an evaporation-indu…
Primary alkynyl phosphine porphyrins were prepared by AlHCl2 reduction of the corresponding alkynyl phosphonates. Dephosphorylation of the alkyne proved to be a major side reaction. Using LiAlH4 as reducing agent, the alkyne was found to be partially reduced to give the trans-alkenyl phosphine selectively. The primary…
The ongoing evolution from to insulator materials with lower dielectric constant, k , through the introduction of pores, brings new challenges in terms of processing and reliability. Porosity enhances penetration of undesired chemical species. A method of sealing microporous low- k dielectric chemical vapor deposited…
Three organic inhibitors namely, 5-mercapto-3-butyl-4-salicylidineimino-1,2,4-triazole (MBST), 5-mercapto-3-butyl-4-benzylidineimino-1,2,4-triazole (MBBT) and 5-mercapto-3-butyl-4-cinnamylidineimino-1,2,4-triazole (MBCT) were synthesized in the laboratory and their influence on the inhibition of corrosion of mild stee…
Abstract EXAFS spectroscopy is a useful method for determining the local structure around a specific atom in disordered systems. This technique provides information about the coordination number, the nature of the scattering atoms surrounding a particular absorbing atom, the interatomic distance between the absorbing…
Vertically aligned ZnO nanowhiskers have been grown on Si substrates spin-coated with ZnO nanoparticles by metal organic chemical vapor deposition (MOCVD) using Me2Zn·tmeda and a mixture of O2 and Ar gases. The ZnO nanowhiskers grown are single crystals with a growth rate of 3 μm h−1.
The effects of high dose ( 3 × 10 16 cm − 2 ) implantation of Ni, Fe, Co, or Mn ions into bulk, single-crystal SnO 2 substrates carried out at substrate temperature of ∼ 350 ° C to avoid amorphization of the implanted region on the magnetic properties of the material are reported. X-ray diffraction showed no evidence…
Polypropylene fibres which can be conventionally dyeable using disperse dyes have been prepared by alloying with nylon 6 and a polypropylene grafted maleic anhydride compatibiliser during extrusion. The dyeing performance of fibres containing various amounts of these components has been assessed.
This paper deals with the columbite FexMn1−xNb2O6 (x = 0, 0.25, 0.50, 0.75 and 1) solid solution. After synthesis under vacuum, structural and magnetic properties were studied by means of X-ray diffraction, Rietveld refinement, electron paramagnetic resonance and magnetization measurements. This investigation showed t…
Ionic LC-dendrimers were obtained by proton-transfer reaction of alkanoic acid and primary amino groups of poly(amidoamine) dendrimer in a 1:1 molar ratio. The ion complexes containing stearate, palmitate or myristate ions showed a smectic A phase. However, the ion complexes containing laurate and decanoate ions exhib…
A number of AB 2 monomers containing either one azide and two acetylene functions or vice versa have been prepared. Upon polymerization, these compounds were found to give rise to hyperbranched oligomers as detected by NMR spectroscopy. However, the formation of high-molecular-weight polymers could not be proven by GP…
An efficient system for the production of (R)-hydroxyalkanoic acids (RHAs) was developed in natural polyhydroxyalkanoate (PHA)-producing bacteria and recombinant Escherichia coli. Acidic alcoholysis of purified PHA and in vivo depolymerization of PHA accumulated in the cells allowed the production of RHAs. In recombin…
Ceramic pellets of different compositions of Na 1−xKxNbO 3 system (x = 0 to 0.5) have been prepared using ‘solid-state reaction’ method. Pellets of 6 mm diameter have been prepared under two conditions; first, the calcined mixtures were pressed at 0.2 MPa and sintered in a tube furnace opened at both ends; and second,…
We study dielectric properties of a dilute suspension of ferroelectric particles in a nematic liquid crystal(LC)host. It is supposed that submicron particles do not disturb the LC alignment and the suspension macroscopically appears similar to a pure LC. We propose theoretical model for effective dielectric function o…
Poly(N-vinyl-2-pyrrolidone)-stabilized Pd-nanoclusters, for the first time exclusively supported on the hydrotalcite lateral surface, showed a remarkable catalytic performance in the selective hydrogenation of 3-hexyn-1-ol, which can be ascribed to both the influence of the protecting polymer PVP as well as the nature…
The electrochromic polymer poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT-PSS) spin-coated on ITO/glass was patterned with a soft lithographic method in order to diffract the incident light and thereby modify absorption of light by the film to improve the electrochromic efficiency of the polymer. The…
The Pnma-Imma-I4/mcm phase transitions of SrZrO3 have been successfully observed by measuring the variation of energies of phonon modes as a function of temperature. The squares of phonon mode frequencies, ω02, exhibit a linear relation with temperature, T, on both sides of the phase transitions. An unusual value of -…
We report on observations of transient behavior of currents induced by the polarity reversal of a dc voltage applied across a nematic liquid-crystal cell. The curve of the time-evolved transient current reveals two peaks for the external voltage larger than a characteristic value. The temperature dependence of drift m…