Materials Literature
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Abstract : This report documents the numerical algorithms used in an explicit Lagrangian finite element hydrocode. One, two, and three dimensional implementations of the numerical solution of the conservation equations are covered. Triangular and tetrahedral continuum elements and shell elements are described. SPH (Sm…
The reaction of Au with a molten mixture of A 2 Q/P 2 Q 5 /Q (Q = S, Se) produced the quaternary compounds A 3 AuP 2 Se 8 (A = K, Rb, Cs) ( I − III ), A 2 Au 2 P 2 Se 6 (A = K, Rb) ( IV, V ), A 2 AuPS 4 (A = K, Rb, Cs) ( VI − VIII ), and AAuP 2 S 7 (A = K, Rb) ( IX, X ). I − III crystallize in the acentric space group…
The effect of oxide crystallinity on the oxidation rate of silicon carbide was investigated. CVD SiC coupons were oxidized in a clean TGA reactor system at 1300°C initially in flowing oxygen, immediately annealed in argon, and then reoxidized, all in situ and without cooling (so as to preserve oxide integrity). The pa…
(1997). BRIDGED POLYCYCLIC AROMATIC HYDROCARBONS. A REVIEW. Organic Preparations and Procedures International: Vol. 29, No. 3, pp. 243-283.
Novel aromatic polyimides containing symmetric, bulky di-tert-butyl substituents unit were synthesized from 1,4-bis(4-aminophenoxy)2,5-di-tert-butylbenzene (BADTB) and various aromatic tetracarboxylic dianhydrides by the conventional two-stage procedure that included ring-opening polyaddition in a polar solvent such a…
We investigate experimentally, using quasi–elastic light scattering the dynamical properties of highly swollen lamellar and “sponge" phases. In our system the structural sizes – smectic period for lamellar phases or characteristic cell size for “sponge" phases – may be changed continuously by adding solvent up to scal…
We use a model previously formulated based on the double-exchange mechanism and diagonal disorder to calculate magnetization and conductivity for ${\mathrm{La}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Sr}}_{\mathrm{x}}$${\mathrm{MnO}}_{3}$-type crystals as a function of temperature. We use the results of the mo…
The phosphoenolpyruvate (PEP) carboxykinase-encoding gene from the anaerobic, CO2-fixing, succinate-producing bacterium Anaerobiospirillum succiniciproducens was cloned, sequenced, and expressed in Escherichia coli. The gene encoded a 532-residue polypeptide with a calculated molecular mass of 58.7 kDa. The sequence o…
A systematic investigation of structure and intrinsic magnetic properties of the novel compounds R3(Fe, T)29 (R=Y, Ce, Nd, Sm, Gd, Tb, and Dy; T=V and Cr) has been performed. The lattice constants and unit cell volume decrease with increasing the rare-earth atomic number from R=Nd to Dy, except for Ce, reflecting the…
The melt-state phase behavior of isotactic polypropylene (i-PP) blended with a series of poly(ethylene/ethylethylene) random copolymers has been investigated using small-angle neutron scattering (SANS). These PEE xx copolymers, where xx is the percentage of ethylethylene (EE) units, were prepared by hydrogenation of a…
The luminescence of and doped with divalent manganese was studied by performing excitation, emission, and decay time measurements in the temperature range from 4.2 to 500 K. From the results of these measurements the following mechanism can be proposed. Excitation into the gallate host lattice leads to the formation o…
Water-soluble calix[4]arenes 10a,b with chromophores ("antenna") attached to the lower rim via a short spacer are described. In the neutral lanthanide complexes of 10a,b photoexcitation of the antenna induces lanthanide emission via intramolecular energy transfer. Calix[4]arene 10b with a chrysene moiety as sensitizer…
Abstract A high increase in the bulk polymerization rate of L,L‐lactide and racemic D,L‐lactide is observed when aluminium isopropoxide is added with an equimolar amount of a Lewis base, such as triphenylphosphine (P(ϕ) 3 ) and better 4‐picoline (C 6 H 7 N). Polylactide of high molecular weight and narrow molecular we…
We have identified three smectic phases, smectic A, ferrielectric and antiferroelectric, in a free-standing film of the first component compound of the mixture which was reported to show the V-shaped switching usable for realizing attractive displays [Inui et al. .: J. Mater. Chem. 6 (1996) 671]. The switching in the…
Three axially bis-ligated Fe(II) porphyrinates, [PFeL 2 ], have been investigated by Mössbauer spectroscopy over the temperature range 4.2−230 K and in an applied field of 6 T. Relatively large differences in the quadrupole splitting Δ E Q were found among [TMPFe(2-MeImH) 2 ] ( 1 ), [TMPFe( N -MeIm) 2 ] ( 2 ), and [OE…
We consider the phase behavior of a symmetric AB diblock, blended with corresponding A and B homopolymers, all of equal chain length. Evaluating the phase diagram in mean-field theory at all compositions of the ternary blend, we find no hexagonal and cubic phases. However, up to three distinct lamellar phases can coex…
The direct reaction of liquid (or melted solid) 1-alkanols or 1,omega-alkanediols with solid finely ground VOPO(4). 2H(2)O in a microwave field leads to layered complexes of the composition VOPO(4).2C(n)()H(2)(n)()(+1)OH (n = 1-18) or VOPO(4).C(n)()H(2)(n)()(OH)(2) (n = 2-10), respectively. The results of X-ray diffra…
Bimetallic complexes of the type (C 5 Me 5 ) 2 Sm−R−Sm(C 5 Me 5 ) 2 were used for the living bis-initiated polymerization of methyl methacrylate and ε-caprolactone, giving polymers with discrete functionalities at the center of the backbone (“link-functionalized”). Poly(methyl methacrylate) containing olefin units was…
The synthesis and characterization of a polymer composite system containing quantum-confined II−VI semiconductor particles entrapped in a polyphosphazene network is discussed. A hybrid material was constructed using a guest:host approach in which the ion transporting ability of [NP(OCH 2 CH 2 OCH 2 CH 2 OCH 3 ) 2 ] n…
It is demonstrated that the current-voltage characteristics of platinum-thin insulator silicon carbide diodes react rapidly to changes of the concentration of oxygen and hydrocarbons in the ambient already at temperatures around 500/spl deg/C-600/spl deg/C. In this letter, we use moving gas outlets to, for the first t…