Materials Literature
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A new procedure for the synthesis of mesoporous alumina membranes is presented. Using this technique, catalytic membranes with precise active layer width and location were prepared by sequential slip-casting of Pt/alumina and alumina sols. Different distributions of catalyst within the membrane can be easily obtained…
3-(o-Carboranylhydroxymethyl)-7-isopropylazulene sodium carboxylate (1) and 3-(o-carboranylmethyl)-7-isopropylazulene sodium sulfonate (2) were synthesized from the palladium-catalyzed addition reaction of 1-carboranyltributylstannane (4) to azulene aldehydes (3 and 9). Although the water solubility of 1 was of the or…
A new electron-deficient tentacle porphyrin meso-tetrakis[2,3,5,6-tetrafluoro-4-(2-trimethylammoniumethylamine )phenyl]porphyrin (TthetaF4TAP) has been synthesized. The binding interactions of TthetaF4TAP with DNA polymers were studied for comparison to those of an electron-deficient tentacle porphyrin and an electron…
Epitaxially grown Pb(Zr, Ti)O 3 (PZT, Pb:Zr:Ti=1:0.52:0.48) thin films were prepared on Nb-doped SrTiO 3 (100) substrates by dipping-pyrolysis process with metal naphthenates used as starting materials. The alignments of the films were investigated based on X-ray diffraction (XRD) θ–2θ scans, β scans (pole figures), a…
The infinite hierarchy of differential-recurrence relations for the equilibrium transverse correlation functions appropriate to magnetic relaxation of single-domain ferromagnetic particles with uniaxial anisotropy subjected to a uniform external magnetic field ${H}_{0}$ is derived by averaging Gilbert's equation. Exac…
Domains in certain Langmuir monolayers support a texture that is the two-dimensional version of the feature known as a boojum. Such a texture has a quantifiable effect on the shape of the domain with which it is associated. The most noticeable consequence is a cusplike feature on the domain boundary. We report the res…
This article examines the effects of the soft-segment composition on the structure and physical properties of waterborne polyurethane (WBPU) based on polycaprolactone–poly(ethylene glycol)–polycaprolactone (PCL–PEG–PCL) triblock copolydiol as the soft segment. The molecular weight of PEG in the soft-segment compositio…
A numerical technique has been developed to model texture in nematic liquid crystals. The technique differentiates between splay, twist and bend distortions and includes splay-splay compensation. The technique is tested by the simulation of the Freedericksz transition and by the determination of minimum energy directo…
The microstructures of α‐Al 2 O 3 seeded sol–gel‐derived alumina‐zirconia composites containing 20 wt% unstabilized zirconia (processed from zirconium n‐propoxide) were very fine, with submicrometer alumina grains and small, mainly intergranular zirconia particles, the latter having a critical size for the tetragonal‐…
Abstract Polymer networks showing different smectic polymorphism with either an interdigitated smectic A to undulated smectic A phase transformation or an interdigitated smectic A to double layer smectic C phase transformation are synthesized. Their orientation behavior in uniaxial mechanical fields is investigated by…
Three different sites of the ${\mathrm{Cr}}^{3+}$ ions in the fluoride perovskite ${\mathrm{KMgF}}_{3}$ have been identified by absorption, selective optical excitation, and time-resolved emission spectroscopy of the ${}^{4}{T}_{2}{\ensuremath{\leftrightarrow}}^{4}{A}_{2}$ transition. High-pressure measurements showin…
The synthesis of carboxyl-terminated poly(ethylene glycol adipate) (CTPA) and amine-terminated poly(amide sulfone) (ATPS) based on the CTPA and 4,4′-diaminodiphenyl sulfone (DDS) is described. The products were characterized by IR and 13C-NMR spectroscopic analysis, nonaqueous titration, viscosity measurement, and sol…
Time-resolved light scattering has been used to investigate phase-separation dynamics for off-critical mixtures of polybutadiene (PB) and polyisoprene (PI) with a well defined phase diagram. Percolation-to-cluster transition (PCT) occurs in the course of the phase separation process for an off-critical mixture of the…
Copolymers containing vinyl sugar units were synthesized by copolymerizing 2,3;4,5-di- O -isopropylidene-1-(4-vinylphenyl)- d -gluco( d -manno)pentitol ( 1 ) with styrene. Films and plates of the copolymers and blends were prepared by casting solutions on glass plates or by hot-pressing. Isopropylidene groups, the hyd…
Based upon the torus parametrization which was introduced recently, we present a recipe allowing for a complete analysis of the symmetry structure of quasiperiodic local isomorphism classes in one and two dimensions. A number of results is provided explicitly, including some widely used planar tiling classes with 8-,…
The rates of the reactions of ethyl radicals with HBr ( k 7 ) and with Br atoms ( k 8 ) have been measured in the temperature range 228−368 K at millitorr pressures using the very low pressure reactor (VLPR) technique. The Arrhenius function for the H atom abstraction reaction is found to be k 7 = (1.43 ± 0.06) × 10 -…
Dielectric spectroscopy is employed in two polystyrene−polyisoprene−polystyrene (SIS) triblock copolymers well below the order-to-disorder transition temperature and in the frequency range from 10 -2 to 10 6 Hz. Small angle X-ray scattering has shown the formation of lamellar structures with a long period of about 25…
Cobalt porphyrins in which Ru(NH3)52+ groups are coordinated to four cyanophenyl ligands pendant to the porphyrin ring act as catalysts for the electroreduction of O2 when adsorbed on the surface of graphite electrodes. The parent 4-cyanophenyl derivative catalyzes the four-electron reduction of O2 to H2O, but the 4-c…
The comparison of the results of calculations based on experimental data with those derived from a simple, two phase, elastic model proved the existence of a hard interphase in particulate-filled composites. Moreover, beside elastic properties, also other mechanical characteristics of the interphase, including yield s…
We have performed a neutron-diffraction study of the Laves hydride ${\mathrm{YMn}}_{2}{\mathrm{H}}_{4.3}$ to investigate the interplay between the atomic order in the hydrogen sublattice and the magnetic structure. We find that structural order in the H sublattice and antiferromagnetic order in the Mn sublattice have…