Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTExploring the Limits of Efficiency of Proton-Transfer Catalysis in Models and EnzymesEwa Hartwell, David R. W. Hodgson, and Anthony J. KirbyView Author Information University Chemical Laboratory, Cambridge University Cambridge CB2 1EW, UK Cite this: J. Am. Chem. Soc. 2…
In the Sr–Bi–Ta–Nb–O system, three crystallographic phases are known to exist: the SrBi 2 (Ta 1- x Nb x )O 9 (SBTN) perovskite, fluorite and pyrochlore phases. It is considered that the fluorite phase is a low-temperature phase of SBT, which tends to grow in excess bismuth compositions, and the pyrochlore phase tends…
Both phenomenological and molecular-statistical theories of the anticlinic smectic-C(A) phase (Sm-C(A)) are considered in detail. The anticlinic structure produces antiferroelectricity in the chiral smectic-C(A) phase (Sm-C(A)*). The molecular theory is based on a simple model potential which stabilizes Sm-C(A) with r…
Two electrochemical methods designed for the synthesis of polypyrrole (PPy) wires and nanotubules are the topic of this paper. The concept that allows the morphology of PPy to be controlled is discussed for each method, and the performances of the two complementary techniques are compared in terms of dimension, shape…
The structure of the Sr 0.75 Ba 0.25 Nb 2 O 6 single crystal has been investigated by x-ray diffraction. The occupancies of the Ba and Sr sites in two structural channels are determined. It is found that these sites are split in the large (pentagonal) channel. A qualitative correlation is revealed between the smearing…
Banana-shaped molecules having two side wings attached to a bent core may exhibit liquid crystallinity. The most studied material is 8-OPIMB that comprises 1,3-dihydroxybenzene as a central core, a Schiff 's base moieties as the wing groups and octyloxy tail groups. To clarify the effect of chemical structure on the l…
The first-principles calculations for FeMn and MnPt alloys both of ordered and disordered phases have been performed with the TB-LMTO method combined with the CPA. The magnetic structure of FeMn in the disordered phase is suggested to be non-collinear 3Q structure where the average moment is around 1.7 µ B and the Nee…
The results of the direct deposition of lead zirconate titanate [Pb(Zr 0.52 , Ti 0.48 )O 3 ] (PZT) thick film on a Si-based structure are presented. The construction of a bottom electrode is very important for successful deposition. The actuation properties of PZT on the Si membrane were investigated. For a 6.2×6.1 mm…
Interparticle interactions in charge-stabilized colloidal suspensions, of arbitrary salt concentration, are described at the level of effective interactions in an equivalent one-component system. Integrating out the degrees of freedom of all microions from the partition function, and assuming a linear response to the…
The charge disproportionation and the magnetic properties of Sr 3 Fe 2 O 7 , which has a double-layered perovskite structure, have been investigated. From 57 Fe Mössbauer measurements, the Néel temperature T N and the critical temperature for the charge disproportionation reaction (2 Fe 4+ → Fe 3+ + Fe 5+ ) are determ…
An increasing body of evidence suggests that an endogenous mammalian bufadienolide (BD) may be involved in the regulation of Na(+),K(+)-ATPase activity and the pathogenesis of arterial hypertension. We developed a purification scheme for marinobufagenin (MBG), an amphibian cardiotonic BD, and applied it to purify and…
A detailed investigation of the solution structure of two Yb(III) complexes of C 4 symmetric chiral tetraamide ligands based on cyclen is performed in different solvents with the combined use of 1 H NMR, NIR-CD, and luminescence techniques. Pseudocontact chemical shifts and NOE measurements allow one to assess the rel…
Abstract This study examined the effects of impact modifier types and addition levels on the mechanical properties of rigid PVC/wood‐fiber composites. The impact resistance of rigid PVC/wood‐fiber composites depends strongly on the type and content of impact modifier. With the proper choice of modifier type and concen…
Trains of juxtaposed drops in a tube are described and found to move spontaneously, in wetting conditions, because of their asymmetry. We focus on the coating properties of these devices, and show in particular that highly viscous species can be (self-) transported, thanks to the lubricating film left by the first dro…
Fluorinated amorphous-carbon films (a-C:F:H) were deposited by low-power rf capacitively coupled plasma-enhanced chemical-vapor deposition using CH4–CF4 gas mixtures. Different series of films were deposited, changing one parameter at a time: the CF4 partial pressure from 0% to 100%, the self-bias voltage from −50 to…
The dynamics of supercooled salol (phenyl salicylate) was measured in the time domain using optical Kerr effect techniques. By combining several experimental setups, data spanning more than six decades in amplitude and time (∼100 fs to ∼1 μs) were observed. The data have a complex shape, ranging from high-frequency in…
The investigation of two perovskite manganites with the same carrier concentration of 0.1 electron per Mn has been performed using neutron powder diffraction and electron microscopy, and completed with transport and magnetic measurements. For ${\mathrm{Sm}}_{0.1}{\mathrm{Ca}}_{0.9}{\mathrm{MnO}}_{3},$ whatever the tem…
A ligand with a linear arrangement of three coordination pockets produces a Cu9O12, alkoxide-bridged, square grid of closely spaced copper centers (see picture) in high yield by a strict self-assembly process. Orthogonal bridging connections within the grid lead to dominant intramolecular ferromagnetic coupling with a…
The single-crystal X-ray structures of three odd-membered thiophene oligomers bearing one central thienyl- S, S -dioxide moiety trimer, pentamer, and heptamer are reported. Absolute photoluminescence quantum yields in microcrystalline powders are given for all compounds. The solid-state photoluminescence efficiencies…
The crystallographic and magnetic properties of the $\mathrm{Mn}[\mathrm{N}(\mathrm{CN}{)}_{2}{]}_{2}$ compound have been investigated by dc magnetization, ac susceptibility, specific heat, and zero-field neutron diffraction on polycrystalline samples. The magnetic structure consists of two sublattices which are antif…