Materials Literature
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Tetragonal BaTiO 3 powders were prepared hydrothermally, using Ba(OH) 2 ·8H 2 O and TiO 2 (anatase), in the absence of anions such as chloride ions, at a temperature of 220°C for several days. Characterization via X‐ray diffractometry, scanning electron microscopy, and differential scanning calorimetry confirmed that…
We present large scale atomistic simulations of crack growth in iron under quasistatic loading in mode I. We show that long cracks display a brittle character of extension, while the growth of smaller cracks is accompanied by emission of partial dislocations from the crack tip and subsequent transformation of the stac…
Abstract Seeded batch experiments were conducted at low magma densities and moderate ionic strength to determine the growth and aggregation rate constants for calcite precipitation in a stirred vessel. The growth was found to be surface‐reaction‐limited, and the growth rates agreed broadly with other studies of calcit…
Fully dense disks, each consisting of a single crystal (111) plate of the relaxor‐based ferroelectric Pb(Mg 1/3 Nb 2/3 )O 3 ‐35 mol% PbTiO 3 (PMN‐35PT) embedded in a 0.48 ± 0.05 µm grain size polycrystalline matrix of the same composition, were formed by hot‐pressing at 950°C for 30 min under 20 MPa. Specimens were su…
The dibutyltin diacetate-catalyzed reaction of (tridecafluoro-1,1,2,2-tetrahydrooctyl)triethoxysilane (FTEOS) with dihydroxy-terminated poly(dimethylsiloxane), HO(Me 2 SiO) n H, has been used to prepare surface-modified siloxane networks. Surface characterization of these elastomers was carried out with electron spect…
Effects of the support environment on the existence of Cu ion pairs in Cu-exchanged ZSM-5 catalysts are examined using density functional theory. Results for the molecular and electronic structures of O- and O 2 -bridged Cu oxocations ([CuOCu] 2+ and [CuO 2 Cu] 2+ ) are presented, including two distinct isomers for th…
The synthesis, characterization by XRD, UV-vis, IR and TGA and the magnetic properties of four layered compounds, namely1 Co5(OH)8(H2O)2 (NO3)2;2 Co5(OH)8(O2 CC6H4CO2) · 2H2O;3 Co2 (OH)3(NO3);4 Co4(OH)2(O2 CC6H4CO2)3 · (NH3)1.5 (H2O)2.5,are reported. 1 and 2 are characterized by triple–deck layers consisting of both o…
The ability of two montmorillonites, SWy‐2 and SAz‐1, one hydrotalcite, HT [(Mg3Al(OH)8)2 • CO3 • 4H2O], and some of their organoderivatives (organo‐clays and organohydrotalcites) to sorb the ionizable pesticide imazamox (2‐[4,5‐dihydro‐4‐methyl‐(l‐methylethyl)‐5‐oxo‐lH‐imidazol‐2‐yl]‐5‐(methoxymethyl)‐3‐pyridinecarbo…
We present a scaling theory to describe the equilibrium structure of an annealed polyelectrolyte brush interacting with multivalent salt ions. We demonstrate that at low ionic strengths of the solution the polyelectrolyte brush swells with increases in the bulk concentration of salt, Φ s . When multivalent counterions…
Residual stress distributions in ceramics can be calculated for a coordinate system fixed by the specimen geometry as well as for the crystal system. Computations were performed using alumina as a model system with the residual stresses caused by thermal expansion anisotropy. Mean values and standard deviations of the…
The transition to ferromagnetic order was realized in 1991 with the discovery of a p–nitrophenyl nitronyl nitroxide (C13H16N3O4) crystal. This was the first example of a ferromagnet without metal elements. Its ferromagnetism below the transition temperature of 0.6 K has been established by various experiments such as…
We studied the magnetic anisotropy of two molecular magnets, ${\mathrm{Fe}}_{6}$ and ${\mathrm{Fe}}_{10},$ which comprise six- and ten-membered rings of antiferromagnetically coupled iron (III) ions ${(S}_{i}=\frac{5}{2}),$ respectively. Spin-flip transitions induced by the applied magnetic field (up to 23 T) were inv…
In low‐pressure environments, precipitation of graphite is hindered at low to moderate temperatures by the high solubility of carbon in C‐O‐H fluids and by kinetic barriers to nucleation. Those low‐temperature fluids that do attain saturation tend to precipitate graphite continuously during flow and cooling, thereby p…
The effects of Ga doping on Mn site in the colossal magnetoresistance material ${\mathrm{La}}_{0.67}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}$ have been studied by preparing the series ${\mathrm{La}}_{0.67}{\mathrm{Ca}}_{0.33}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}{\mathrm{O}}_{3}$ $(x=0.0,0.02,0.05,0.1).$ Upon…
The length-scale dependence of the dynamic entropy is studied in a molecular dynamics simulation of a binary Lennard-Jones liquid above the mode-coupling critical temperature T(c). A number of methods exist for estimating the entropy of dynamical systems, and we utilize an approximation based on calculating the mean f…
The complex conductivities between 10 mHz and 1 MHz of a series of disordered carbon-black-polymer composites have been measured. The carbon black volume fractions span the percolation threshold, with dc conductivities ranging from ${10}^{\ensuremath{-}18}$ to ${10}^{\ensuremath{-}6}(\ensuremath{\Omega}\mathrm{cm}{)}^…
The role of surface nitrogen in the kinetics of the NO+CO conversion reaction on Rh(111) under steady-state catalytic conditions was explored by using collimated molecular beams and mass spectrometry detection. Two types of kinetically different nitrogen atoms were identified on the surface. The buildup of a critical…
Low temperature plasma treatments of wool modify only the cuticle surface of the fibers, improving their surface wettability, dyeability, fiber cohesion, and shrink resistance. The shrink-resist properties obtained with plasma treatment do not impart a machine-washable finish, which is an important end-user demand. Ho…
A novel neutral nickel complex molecule with the extended TTF dithiolato ligand, propylenedithiotetrathiafulvalenedithiolate [ptdt 2- = (S 8 C 9 H 6 ) 2- ], was synthesized. In the [Ni(ptdt) 2 ] crystal. [Ni(ptdt) 2 ] molecules form one-dimensional columns along the a axis, having short intermolecular transverse S···S…
Delta(5)-3-Ketosteroid isomerase from Pseudomonas testosteroni has been intensively studied as a prototype to understand an enzyme-catalyzed allylic isomerization. Asp(38) (pK(a) approximately 4.7) was identified as the general base abstracting the steroid C4beta proton (pK(a) approximately 12.7) to form a dienolate i…