Materials Literature
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Several organic liquid-phase reactions are carried out in the presence of a sparingly soluble reactive solid phase which is gradually dissolved during the course of the reaction. The presence of the reactive solid phase complicates the treatment of kinetic data, since the overall reaction rate is influenced by the sol…
The collective dynamics of a simple model colloidal suspension, namely, a two-dimensional Brownian Yukawa fluid, is studied by Brownian dynamics simulations without hydrodynamic interactions. The results for the intermediate scattering function F(k,t) are employed to assess the quantitative and qualitative accuracy of…
Changes in ionic composition (i.e., doping) accompany changes in the redox level of conducting polymers such as polypyrrole. These processes are of paramount interest because they often control the polymer's charge capacity and, more importantly, its rates of oxidation and reduction (i.e., charge and discharge). The m…
A new application of the simulated annealing Monte Carlo procedure is presented and applied to the extraction of the relaxation time distribution from dielectric spectroscopy either in time or frequency domain. This decomposition method named simulated annealing direct signal analysis (SADSA), is applied to computer g…
A new series of Mo(VI) monophosphates containing Te(IV), A 2 TeMo 2 O 6 (PO 4 ) 2 with A = K, Rb, Tl, Cs, has been synthesized. Their crystal structure, determined from single crystals in the Pbcn space group ( a ≈ 12.55−12.37 Å, b ≈ 8.63−9.49 Å, c ≈ 11.13−11.51 Å), consists of corner-sharing PO 4 tetrahedra, MoO 6 oc…
Citrate lyase (EC 4.1.3.6) catalyzes the cleavage of citrate to acetate and oxaloacetate and is composed of three subunits (alpha, beta, and gamma). The gamma-subunit serves as an acyl carrier protein (ACP) and contains the prosthetic group 2'-(5' '-phosphoribosyl)-3'-dephospho-CoA, which is attached via a phosphodies…
An unusual adduct, [{Pt 2 Ag 4 (C⋮C- t -Bu) 8 ·(bipy)}] ∞ ( 3 ), has been obtained from the reaction of the hexanuclear cluster [Pt 2 Ag 4 (C⋮C- t -Bu) 8 ] ( 1 ) with 2,2‘-bipy independently of the molar ratio (1:1 or 1:excess) employed. The crystal structure of 3 shows the presence of an extended polymeric chain cons…
In our current discussion of the thermodynamics and molecular kinetics of glass-forming liquids, the entropy is extrapolated below a liquid’s vitrification temperature Tg along a curve of progressively increasing slope until a temperature Tk is reached. Here the entropy and heat capacity, Cp, of the equilibrium liquid…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSynthesis of Nanocrystalline Bismuth in Reverse MicellesEdward E. Foos, Rhonda M. Stroud, Alan D. Berry, Arthur W. Snow, and J. Paul ArmisteadView Author Information Chemistry Division, Code 6174 Naval Research Laboratory, Washington, D.C. 20375 Cite this: J. Am. Chem.…
Two different polymorphic forms of free base phthalocyanine films have been grown on glass substrates by ultrahigh vacuum organic molecular beam deposition. Postgrowth annealing of films grown at room temperature leads to transformation from the α to the β 1 phase. The effects of annealing lead to a number of transiti…
All-optical switching of selectively reflected colors based on isomerization of an azobenzene (Azo) and subsequent change in transmittance was investigated in cholesteric liquid crystals (LCs) which reflect light in the visible region. Photoirradiation at 366 nm, which causes an efficient trans-cis isomerization of Az…
We theoretically study the nonlinear optical response and photoexcited states of the Mott insulators. The nonlinear optical susceptibility χ^(3) is calculated by using the exact diagonalization technique on small clusters. From the systematic study of the dependence of χ^(3) on dimensionality, we find that the spin-ch…
The rheology of rigid rod cellulose whisker suspensions has been investigated. The isotropic-at-rest suspension flow curves show two plateaus, one at low shear rates and another at high shear rates, that reflect the flow of isotropic (at low shear rates) or oriented (at high shear rates) suspensions. From the low shea…
Sonoluminescence is the production of light from acoustically forced bubbles; sonochemistry is a related chemical processing technique. The two phenomena share a sensitive dependence on the liquid phase. The present work is an investigation of the fate and consequences of water vapour in the interior of strongly force…
Shaped silver nanoparticles with spheres, rods, and dendrites have been prepared by a pulse sonoelectrochemical technique from an aqueous solution of AgNO 3 in the presence of nitrilotriacetate N(CH 2 COOH) 3 -NTA. The silver nanoparticles were characterized by using transmission electron microscopy, X-ray diffraction…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTFirst Observation of Photoinduced Nitrosyl Linkage Isomers of Iron Nitrosyl PorphyrinsLin Cheng, Irina Novozhilova, Chris Kim, Andrey Kovalevsky, Kimberly A. Bagley, Philip Coppens, and George B. Richter-AddoView Author Information Department of Chemistry State Univers…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTFormation of a Novel Luminescent Form of Gold(I) Phenylthiolate via Self-Assembly and Decomposition of Isonitrilegold(I) Phenylthiolate ComplexesRobert E. Bachman, Sheri A. Bodolosky-Bettis, Shana C. Glennon, and Scott A. SirchioView Author Information Department of Ch…
Four years ago, the U.S. Environmental Protection Agency (EPA) ignited a fire storm when it declared that tens of thousands of people were dying each year from breathing tiny particles of dust and soot--and issued tough new regulations to crack down on these pollutants. Industry groups and many scientists assailed the…
The redox states of a series of well-defined hybrid dendrimers based on oligothiophene cores and poly(benzyl ether) dendrons have been studied using cyclic voltammetry and variable-temperature UV/visible/near-IR spectroscopy. The oxidation potentials and the electronic transitions of the neutral, singly oxidized, and…
Starlike HPMA copolymers were synthesized by conjugating semitelechelic poly[N-(2-hydroxypropyl)-methacrylamide] macromolecules (ST-PHPMA, arm) with PAMAM dendrimers (core: G2, G3, G4). ST-PHPMA was synthesized by chain transfer free radical polymerization, and the terminal -COOH was activated with N-hydroxysuccinimid…