Materials Literature
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Nanocomposites were prepared from styrene butadiene rubber (SBR) having different styrene contents and octadecyl amine modified Na‐montmorillonite clay (OC). The modified and the unmodified clays were characterized with the help of X‐ray diffraction technique (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and T…
In the present work, we report the epitaxial growth and dielectric properties of barium strontium titanate (BST) thin film which can be used to make frequency and phase agile tunable microwave (MW) components with a high performance, such as tunable filters, tunable oscillators, and phase shifters for application in p…
The <IMG SRC="/fbpe/img/jcchems/v49n3/alfa.jpg" WIDTH=12 HEIGHT=12>-pinene isomerization reaction was studied on catalysts based on H3PW12O40 (HPW) supported on TiO2, SiO2 and ZrO2nH2O. Catalysts with a 40% nominal charge of phosphotungstic acid (HPW) were prepared by impregnation of supports with a HPW solution…
Abstract Diffusion couples and equilibrated alloys have been investigated in order to contribute to the knowledge of Ti–Zn phase diagram. Differential scanning calorimetry, X-ray methods and scanning electron microprobe analyses are applied. Diffusion couples studies show that TiZn3 layers grow directly from the Ti–Zn…
The effects of incorporation of lanthanum (La 3+ ) ions in Na 1/2 Bi 1/2 TiO 3 (NBT) on microstructure and sintering characteristics were studied. As the content of incorporated La 3+ increased in [(Na 0.5 Bi 0.5 ) 1-1.5 x V 0.5 x La x ]TiO 3 , the sintered density reached a maximum at x =0.05 and the grain size decre…
Photo-induced phenomena in glasses excited by two-photon absorption have been studied and compared with those produced by bandgap illumination. The two-photon excitation of As2S3 gives a refractive-index increase, unaccompanied by photodarkening. Raman-scattering spectra show that the excitation increases the density…
The photogeneration of Ag particles and clusters with 350 nm photons was studied in thin films containing poly(vinyl alcohol) and poly(acrylic acid) that were crosslinked with glutaraldehyde. Product formation occurred through two consecutive processes that were linear functions of time. Kinetic determinations showed…
Blue and ultraviolet upconversion (UC) emissions at 455 and 363nm were observed from Tm3+ doped fluoroindate glasses pumped at 650nm. The time behavior of the UC signals was studied for different Tm3+ concentrations. The measurements revealed the origin of the UC process as well as allowed to quantify the interaction…
Domain wall structures on the etched surfaces of the solid solutions of Pb(Zn 1/3 Nb 2/3 )O 3 - x PbTiO 3 (PZN- x PT; x =8%, 20%) were investigated by atomic force microscopy (AFM). Ferroelectric and ferroelastic domain wall structures were observed. In the rhombohedral phase, a zigzag domain wall structure was found.…
Crack propagation along grain boundaries in sintered silicon nitride (Si3N4) was investigated by in-situ straining experiments at room temperature in a transmission electron microscope, using a high-precision microindenter. Using this in-situ technique, cracks introduced were introduced in situ and observed propagatin…
Abstract Glauconitic grains are abundant in sandstones and siltstones from Albian and Cenomanian (transition between Lower and Upper Cretaceous) formations of southeastern France. Morphological and crystal-chemical data show that the "green grains" can be considered as glauconite s.s., with minute amounts of pyrite, d…
The effects of different carbon and nitrogen sources on the growth, nitrogenase activity, and carbon metabolism of Gluconacetobacter diazotrophicus were investigated. The amino acids asparagine, aspartic acid, and glutamic acid affected microbial growth and nitrogenase activity. Several enzymatic activities involved i…
Abstract Starch/poly(vinyl alcohol) (PVA) composite foams were prepared by baking a mixture of starch, PVA, and other ingredients in a hot mold. The effects of relative humidity, storage period, PVA content, and type and content of plasticizer (e.g. glycerol, urea, or ammonium chloride) on moisture content, water abso…
Basic electromigration characteristics of SiN x -passivated single-damascene Cu lines have been investigated. The results indicate that an effective incubation time for void growth contributes to resistance change. This effective incubation time depended inversely on the square of current density. The activation energ…
(111) c - and (100) c -oriented SrRuO 3 films were successfully grown on (111)Pt/TiO 2 /SiO 2 /(100)Si and (100)LaNiO 3 /(111)Pt/TiO 2 /SiO 2 /(100)Si substrates, respectively, by RF-magnetron sputtering method. On these (111) c - and (100) c -oriented SuRuO 3 films, (111)- and (001)/(100)-oriented fiber-textured Pb(Z…
Abstract Composites of polypropylene (PP) and non‐treated sisal fiber (SF) were prepared in a non‐conventional two‐step process that offers significant advantages. Maleic anhydride–grafted polypropylene (MA‐g‐PP) was used as a coupling agent, to improve adhesion between the polar sisal fiber and the non‐polar polyprop…
Bistability in deformed helix ferroelectric liquid crystal (DHFLC) has been investigated by electro-optical and dielectric methods and compared with the bistability phenomenon in surface stabilized ferroelectric liquid crystal (SSFLC). Bistability in DHFLC as well as SSFLC is based on different physical phenomena. In…
Solid phosphoric acid catalyzed oligomerization of 1-butene rich material yielded highly branched products that were not expected from a standard carbocation mechanism. This peculiar oligomerization behavior of 1-butene has been noted previously in the literature and the present study deals with its explanation. Evide…
Silicon nitride microsieves are excellent candidates for their use in membrane emulsification processes. These microsieves have well‐defined pores with extremely narrow pore size distributions. To produce water in oil emulsions the surface of the microsieves has to be altered from a hydrophilic to a hydrophobic state.…
Novel ceramides, rel-(3S,4S,5S)-3-[(2R)-2-hydroxycosanoyl-hexacosanoylamino]-4-hydroxy-5-[(4Z)-tetradecane-4-ene]-2,3,4,5-tetrahydrofuran (1a-g), and a new glucoceramide, 1-O-beta-D-glucopyranosyl-(2S,3S,4R,8E)-2-[(2R)-2-hydroxytetracosanoylamino]-1,3,4-octodecanetriol-8-ene (2) were isolated from the aqueous ethanoli…