Materials Literature
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The direct formation of iron phosphate nanoparticles on hydroxyl-terminated SiO(2)/Si substrates with a narrow size distribution (average diameter = 2.2 nm) is achieved by a simple room temperature spontaneous reaction of ferric chloride and phosphoric acid. Single-walled carbon nanotubes (SWNTs) are grown in high yie…
Abstract The in situ Fourier transform infrared spectroscopic study of isotactic polypropylene showed that structural changes are induced at liquid nitrogen temperature, and start to show up in the FTIR spectra with heating from −196 to +200 °C. This structural change leads to the detection of an abnormal behavior in…
Infrared (IR) chemiluminescence studies of CO2 formed during steady-state CO + NO reaction over Pd(110) and Pd(111) surfaces were carried out. Kinetics of the CO + NO reaction were studied over Pd(110) using a molecular-beam reaction system in the pressure range of 10-2-10-1 Torr. The activity of the CO + NO reaction…
The unusual suspects: By using a series of ruthenium clusters of the type [{Ru3O(μ-CH3COO)6(CO)L′}(μ-L){Ru3O(μ-CH3COO)6(CO)L′′}] (see picture) it has been possible to identify the existence of charge-transfer isomers and establish them as identifiable chemical entities that exist in dynamic equilibrium.
A series of new asymmetric bent main-chain liquid crystalline (LC) polyesters (BPE-C n ) were synthesized through the condensation polymerization of A−B type asymmetric α,ω-carboxylic acid−hydroxyl-terminated monomers containing different even numbers of methylene spacers (BPCA-C n -P m OH, where n = 6, 8, and 10). Di…
Reconstitution into planar lipid bilayers of a poly-3-hydroxybutyrate/calcium/polyphosphate (PHB/Ca(2+)/polyP) complex from Escherichia coli membranes yields cationic-selective, 100 pS channels (Das, S., Lengweiler, U.D., Seebach, D. and Reusch, R.N. (1997) Proof for a non-proteinaceous calcium-selective channel in Es…
Abstract The present study examined poly(ethylene terephthalate) (PET) and a series of statistical and blocky copolymers in which up to 30% of the terephthalate was replaced with isophthalate by copolymerization and melt blending, respectively. Some level of transesterification during processing of melt blends resulte…
Abstract Seed gum from Ipomoea dasysperma was grafted with polyacrylonitrile using potassium persulfate/ascorbic acid redox initiator in the presence of molecular oxygen, where the maximum percentage grafting and percentage efficiency observed were 360 and 97.2%, respectively. Optimal grafting conditions were establis…
Supramolecular dendrimers resulting from the dimerization of fullerene-functionalized dendrons through a quadruple hydrogen-bonding motif were prepared. The synthetic strategy is based on the esterification of a tert-butoxycarbonyl (Boc)-protected 2-ureido-4-[1H]pyrimidinone precursor possessing an alcohol function wi…
Abstract The present study examined crystallization of poly(ethylene terephthalate) (PET) and a series of random and blocky copolymers in which up to 30% of the terephthalate was replaced with isophthalate. Isothermal crystallization kinetics and direct observation of the spherulitic morphology revealed that the block…
Series of polycarboxybetaines (PCB-n) of pyridiniocarboxylate structure with the same degree of polymerization but differing in the number, n, of methylene groups in the alkyl spacer between charges in the betaine moieties, n = 1, 2, 3, 4, 5, and 8, were synthesized. The utility of PCB-n as positively charged componen…
The crystal structure of Zr 2 Al 3 C 4 was refined by the Rietveld method from conventional X‐ray powder diffraction data. The structure was hexagonal (space group P 6 3 mc , Z =2) with a =0.334680(6) nm, c =2.22394(3) nm, and V =0.215731(6) nm 3 , being isomorphous with that of U 2 Al 3 C 4 . The final reliability in…
We consider the pretilt alignment of a nematic liquid crystal (LC) on inhomogeneous surface patterns comprising patches of homeotropic alignment domains in a matrix favoring homogeneous alignment, or vice versa. We found that the resultant LC pretilt generally increases continuously from the homogeneous limit to the h…
The effect of microstructure on the sliding‐wear properties has been studied in two types of pressureless liquid‐phase‐sintered (LPS) SiC ceramics, one with coarse, in situ ‐grown elongated grains and the other with fine, equiaxed grains. Elongated‐grain LPS SiC has been found to have dramatically improved sliding‐wea…
Nickel oxide yttria‐stabilized zirconia (NiO–YSZ) anode materials were synthesized via hydrolysis of the corresponding chloride solutions with NH 3 , NH 3 +NaOH, and NaOH as precipitation agents. Powder properties such as crystallite size, morphology, and sintering behavior of the final NiO–YSZ materials were also stu…
Abstract The sol–gel method is one of the most suitable ways for producing glasses, glass films, glass fibers, and glass nanoparticles. The relatively mild reaction conditions and simplicity of the sol–gel method make it an excellent tool for producing substances with precisely tailored properties. This technique open…
Abstract The electrical conductivities of various polyolefins filled with a high‐structure carbon black (CB) were studied. Typical percolation behaviors were observed in all of the materials studied. At a critical CB content, which defined the percolation threshold, CB formed conductivity pathways, and resistivity fel…
We report experiments on spontaneous imbibition of a viscous fluid by a model porous medium in the absence of gravity. The average position of the interface satisfies Washburn's law. Scaling of the interface fluctuations suggests a dynamic exponent $z\ensuremath{\simeq}3$, indicative of global dynamics driven by capil…
Arterial prostheses made of microporous Teflon (ePTFE) are currently used in vascular surgery as bypasses for small and medium vessels. However, several clinical complications, such as thrombosis, frequently occur in these prostheses when implanted in humans. In this work, an original strategy was developed to improve…
Reactivity and swelling of nanometer films of alternating maleic anhydride copolymers were investigated in dependence on the kind of comonomer and molar mass of copolymer in aqueous solution at pH 7.4 and pH 3.0 in order to reveal their characteristics under physiological conditions. Fully hydrolyzed (maleic acid) cha…