Materials Literature
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The structure of poly (ε-caprolactam) (nylon 6) in the β mesomorphic form is here examined. The comparison of the diffraction intensity, calculated on modeled structures, with the experimental profiles, collected by us through an automatic diffractometer, is presented. This analysis has put into evidence the following…
Abstract Free radical polymerization of methyl methacrylate (MMA) within the uniform channels of the mesoporous zeolite MCM‐41 proceeds at 100°C to give a high molecular weight polymer (PMMA). The formation of long‐living propagating polymer‐radicals is observed by electron paramagnetic resonance (EPR). The molecular…
To identify novel genes and to isolate tagged mutations in known genes that are required for the development of the peripheral nervous system (PNS), we have screened a novel collection of 2460 strains carrying lethal or semilethal P element insertions on the third chromosome. Monoclonal antibody 22C10 was used as a ma…
High-energy milling provides an effective and environmentally conscious method for nanosizing silicon. Colloidal suspensions of nanosized silicon are presently demonstrated and utilized for the fabrication of high refractive index nanocomposites. Si nanoparticles with average sizes of 20−40 nm and size distributions o…
The effect of water sorption on the dielectric relaxation processes of nylon-6 samples with water concentrations ranging from the dry to the water-saturated polymer has been studied by thermally stimulated depolarization currents experiments in a broad temperature range, from 77 to 365 K. The strengths of the low-temp…
The formation of precursors and the growth and aggregation of silicalite-1 crystals using tetrapropylammonium as a template (Si-TPA-MFI) has been studied in situ using X-ray scattering techniques. Simultaneous small-angle and wide-angle X-ray scattering (respectively SAXS and WAXS) experiments using synchrotron light…
Mechanistic modeling of protein adsorption has evolved to include increasingly detailed descriptions of protein structure in an effort to capture experimentally observed behavior. This has been especially true of electrostatically driven adsorption, for which colloidal models have been used frequently. These efforts h…
We report the existence of a reversible first-order phase transition of BeS from the zinc-blende structure, $B3,$ to the nickel-arsenide structure, $B8,$ at 51 GPa with a volume change of 11%. The NiAs phase remains stable up to at least 96 GPa. A second-order Birch equation describes the equation of state of the $B3$…
Different porphyrin conformations are believed to play a role in controlling the cofactor properties in natural tetrapyrrole-protein complexes. In order to study the correlation between macrocycle nonplanarity and physicochemical properties in detail, a series of six porphyrins with graded degrees of macrocycle distor…
Vanadyl salen complexes bearing electron-withdrawing substituents have been prepared and characterized. Systematic substitutions on the ancillary ligand have allowed V(5+)/V(4+) reduction potentials to be tuned over a range of approximately 500 mV. The complexes are catalysts for the aerobic epoxidation of cyclohexene…
The interaction of hydrous cerium oxide with cationic surfactants under basic conditions is used for the first time in the preparation of CeO2 with enhanced textural and redox properties. The reduction of Ce4+ to Ce3+ is strongly augmented, especially in the low-temperature regime, resulting in a broadening of the win…
Abstract Plasticizers play a key role in the formulation of semirigid and flexible PVC and in determining their physical properties and processability. This study examines the effects of the low phr levels of plasticizer (DOP) on the rheological and mechanical properties of rigid and semi‐rigid PVC/newsprint‐fiber com…
A polystyrene–polyisoprene (PS–PI) diblock copolymer (10,000–50,000 g/mol) and a matched PS&ndashPI–PS triblock (10,000–100,000–10,000 g/mol) were employed to study the effect of chain architecture on the rheological response of ordered block copolymer melts. Both samples adopt hexagonal microstructures with PS cylind…
Magnetoresistance measurements have been carried out on single-crystal sample of the transition-metal Zintl compound Eu 14 MnSb 11 . Eu 14 MnSb 11 is the first compound of the Ca 14 AlSb 11 structure type in which magnetoresistive effects have been measured. Colossal magnetoresistance (CMR) at 92 K and 5 T with Δρ/ρ(0…
The magnetization of the $\mathrm{Co}({\mathrm{S}}_{1\ensuremath{-}x}{\mathrm{Se}}_{x}{)}_{2}$ system with $0<~x<~0.2$ has been measured under high magnetic fields and high pressure. Ferromagnetic ${\mathrm{CoS}}_{2}$ exhibits a second-order transition at ${T}_{c}=122\mathrm{K}.$ Substitution of 10% Se for S in…
Four model compounds (U s, U u, UE ex, and UE in ) and two polyurethanes (PU 1 and PU 2 ) were prepared to monitor the hydrogen-bond (H-bond) interactions of urethane−urethane and urethane−ester (including external and internal esters). The results from differential scanning calorimetry (DSC) and X-ray diffraction sug…
A thin layer electrode of birnessite-type manganese oxide was prepared by brushing a mixed solution of KOCOCH 3 and Mn(OCOCH 3 ) 2 on a platinum substrate, followed by heating at 1073 K. The chemical composition of the electrode was K x MnO y ( x = 0.33 and y ∼ 2) with an interlayer spacing of c 0 = 0.697 nm. The posi…
[M(en)(3)]Sb(2)S(4) (M = Co, Ni) and [M(en)(3)]Sb(4)S(7) (M = Fe, Ni) were prepared from the MX(2)/Na(3)SbS(3)/en system (X = Cl, Br; en = ethylenediamine) under hydrothermal conditions. Orange-yellow [Ni(en)(3)]Sb(2)S(4) (1) crystallizes in the monoclinic space group P2(1)/c (No. 14) with a = 10.538(2) Å, b = 14.460(…
A double water-in-oil-in-water emulsion system was used as a biomimetic environment for the preparation of calcium carbonate particles. Calcium ions were extracted from an external aqueous phase (calcium nitrate solution) into the organic membrane phase (kerosene containing Span 83 as a surfactant and bis(2-ethylhexyl…
Manganese ion-planted MCM-41 was prepared by a “template-ion exchange” method, in which the template ion in as-synthesized MCM-41 was exchanged for Mn2+ ion in an aqueous solution, and the resulting sample was calcined at 873 K. This method was accompanied with no collapse of mesoporous structure. The content of the m…