Materials Literature
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Chain length of substituted n -alkyl groups is proposed to be a convenient design element for the generation of noncentrosymmetric crystal lattices of interest in optical second harmonic generation (SHG). Powder studies on 7,7-Bis( n -alkylamino)-8,8-dicyanoquinodimethanes indicate that moderate solid-state optical SH…
The structural and electronic consequences of reduction and oxidation of a peroxo-bridged Mn(2)(IV/IV) dimer, Mn(2)(&mgr;-O)(2)(&mgr;-O(2))(NH(3))(6)(2+), are examined using approximate density functional theory. In both cases, the initial electron-transfer step is localized on the metal centers, but subsequent struct…
An extension of the replica Ornstein−Zernike (ROZ) equations for partly quenched polydisperse systems is presented. Explicit calculations have been performed for a hard sphere fluid confined by a polydisperse hard sphere disordered matrix. A numerical solution of the ROZ equations makes use of the orthonormal polynomi…
Small angle neutron scattering (SANS) was used for the characterization of the microstructure of carbons derived from organic-loaded inorganic template materials that are used as anodes in lithium ion cells. Pillared clays (PILC), layered silicates whose sheets have been permanently propped open by sets of thermally s…
The dependence on wavelength of repetitive-pulse (10 Hz, 8-10 ns) laser-induced damage on beta barium metaborate (BBO) has been investigated. The thresholds of dielectric breakdown in bulk crystal have been found to be 0.3 GW/cm(2) at 266 nm, 0.9 GW/cm(2) at 355 nm, 2.3 GW/cm(2) at 532 nm, and 4.5 GW/cm(2) at 1064 nm.…
Various functional alkanethiols were found to be able to reduce polyaniline backbones from the emeraldine state 1 to the leucoemeraldine state 2, simultaneously derivatizing the backbones to form functionalized polyanilines. X-ray photoelectron spectroscopy (XPS) studies proved that these thiols formed sulfide bond li…
Magnesium−alumina mixed oxide catalysts at Mg:Al atomic ratios of 3:1, 2:1.8, and 1:2.8 were synthesized by using the sol−gel technique. Dehydroxylation and phase transformations were studied with thermogravimetry. Crystalline structures were measured with X-ray powder diffraction. Position and concentration of anioni…
Pump−probe spectroscopy and steady state emission measurements have been used to demonstrate electron transfer from the excited state populated by excitation in the Soret band (denoted S 2 ) of a zinc porphyrin to a covalently linked ruthenium(II) tris -bipyridine complex (ZnTTP-L-Ru(bpy) 3 ). The lifetime of 1.6 ps m…
The equilibrium geometries, binding energies, electronic structure, and magnetic properties of small stoichiometric MnO clusters are presented for the first time. The results are based on first-principles self-consistent calculations performed within the framework of density functional theory and the generalized gradi…
The molecular weight distribution and its moments for the hyperbranched polymer formed by the polycondensation of an AB 2 type monomer with a multifunctional core moiety were derived rigorously by means of the kinetic method. The variations of several molecular parameters of the growing polymer during the reaction wer…
The isothermal crystallization of three different types of poly[ε-caprolactone- co -ethylene glycol] (PCL−PEG) incompatible block copolymers [A−B, (A) 2 −B, and A−B−A] was investigated using DSC. The PEG weight fraction in the copolymers was slightly varied from 18 to 22 wt %. It was established that the kinetic param…
Solutions containing divalent metal [M(II) = Mg2+, Zn2+, Co2+, Ni2+, Mn2+] chlorides and CrCl3 6H2O were titrated with NaOH to yield, for M(II) = Zn, Co, and Ni, hydrotalcite-like layered double hydroxides (LDHs), [[M(II)]1-z[Cr(III)]z(OH)2][Cl]z yH2O, in a single step, without intermediate formation of chromium hydro…
The combination of two metals in an oxide matrix can produce materials with novel physical and chemical properties. The reactivity of a series of cobalt and nickel molybdates (α-AMoO 4, β-AMoO 4, and AMoO 4 · n H 2 O; A = Co or Ni) toward H 2 and H 2 S was examined using temperature programmed reduction (TPR), synchro…
Extensive molecular dynamics simulations are carried out to study static and dynamic properties of symmetric diblock copolymer melts, both in the disordered and in the lamellar phases. The lamellar phase is constructed using the natural lamellar spacing, determined from constant pressure simulations. The non-Gaussian…
Poly(3,4-ethylenedioxythiophene)/poly(styrene-4-sulfonate) (PEDOT/PSS) composites have been prepared from aqueous and aqueous acetonitrile solutions of EDOT and NaPSS by oxidation using Fe(III) salts. Powders with PEDOT to PSS ratios ranging from 0.3 to 4.2 and electronic conductivities as high as 10 S cm - 1 have bee…
Inclusion complex formation between polyaniline with emeraldine base and β-cyclodextrin has been studied by the frequency-domain electric birefringence (FEB) spectroscopy in a solution of N -methyl-2-pyrrolidone (NMP) and by scanning tunneling microscopy (STM). The FEB results show that polyaniline in the solution wit…
Structural parameters for ordered mesoporous materials are shown to be strongly interrelated as a result of their well-defined structures. Equations for mesoporous materials with hexagonal arrays of uniform pores (e.g., MCM-41 and SBA-15) are presented, which can be used to calculate the pore size, pore wall thickness…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTThe Effect of Temperature Gradient on the Microdomain Orientation of Diblock Copolymers Undergoing an Order−Disorder TransitionTakeji Hashimoto, Jeffrey Bodycomb, Yoshinori Funaki, and Kohtaro KimishimaView Author Information Hashim…
The glass transition temperature of wheat gluten, plasticized with water, glycerol, or sorbitol, has been studied using dynamical mechanical thermal analysis. For the three plasticizers studied, the general behavior of the glass transition temperature broadly followed the Couchman-Karasz relation using a wheat gluten…
Huge built-in electric fields have been predicted to exist in wurtzite III-V nitrides thin films and multilayers. Such fields originate from heterointerface discontinuities of the macroscopic bulk polarization of the nitrides. Here we discuss the background theory, the role of spontaneous polarization in this context,…