Materials Literature
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Neutron diffraction, synchrotron x-ray diffraction, and specific heat studies have been carried out to investigate the nature of the ordered occupation of the vanadium d orbitals in perovskite ${\mathrm{YVO}}_{3}.$ Evidence has been found for a change in the type of orbital ordering at the 77-K phase transition in thi…
Molecular dynamics simulations were employed to investigate the initial stages of growth of calcium, magnesium, iron, cadmium, and strontium carbonates at two experimentally observed calcite steps. The calculated energies suggest that in a solution containing all five cations MgCO 3, FeCO 3, and SrCO 3 grow onto the s…
The (t approximately 0) photodissociation quantum yields (Y(0)) of MbNO and MbO(2) are measured to be 50 +/- 5 and 28 +/- 6%, respectively, using MbCO (Y(0) = 100%) as a reference. When photolysis does not take place, we find that a significant portion of the photon energy contributes to heating of the residual six-co…
We study the spreading kinetics of a monolayer of hard-core particles on a semi-infinite, chemically heterogeneous solid substrate, one side of which is coupled to a particle reservoir. The substrate is modeled as a square lattice containing two types of sites -- ordinary ones and special, chemically active sites plac…
An analytical result for renormalization of the jump of the heat capacity Delta C/C_N by the anisotropy of the order parameter is derived in the framework of the model proposed by Haas and Maki [Phys. Rev. B 65, 020502(R) (2001)], for both prolate and oblate anisotropy. The graph of Delta C/C_N versus the ratio of the…
The spectral density for vector vibrations in the f.c.c. lattice with force-constant disorder is analysed within the coherent potential approximation. The phase diagram showing the weak- and strong-scattering regimes is presented and compared with that for electrons. The weak-scattering regime for external long-wavele…
We report the filling control of the pyrochlore oxide Y2Ir2O7. Metallic ground state appears with increasing substitution content x (x >= 0.3). We have revealed that the density of states at the Fermi level rapidly changes with x by this filling control of Y2Ir2O7.
Raman intensities of Si quantum dots (QD's) with up to 11489 atoms (about 7.6 nm in diameter) for different scattering configurations are calculated. First, phonon modes in these QD's, including all vibration frequencies and vibration amplitudes, are calculated directly from the lattice-dynamic matrix by using a micro…
Single-molecule magnets facilitate the study of quantum tunneling of magnetization at the mesoscopic level. The spin-parity effect is among the fundamental predictions that have yet to be clearly observed. It is predicted that quantum tunneling is suppressed at zero transverse field if the total spin of the magnetic s…
The tiny Ag diffusion to MgCNi3 has been prepared by solid states reaction. Its structure was characterized by X-ray diffractometer (XRD). The results show that a small mount of Ag substitute for Ni sites, and much of Ag are in vacancy sites of the MgCNi3. We have further studied the surface properties of Ag-MgCNi3 us…
A method for the discrete particle simulation of of almost rigid, sharply edged frictional particles, such as railway ballast is proposed. In difference to Molecular Dynamics algorithms, the method does not require knowledge about the deformation-force law of the material. Moreover, the method does not suffer from num…
Aluminum hydroxides are the precursors of metastable aluminas which are used in many applications in industrial catalysis. They constitute a starting point for the understanding of transition processes and structures of metastable transition aluminas. Using first-principle density functional calculations, several poly…
The preparation and characterization of a series of closely related magnesium and zinc compounds are reported: LMg(N(i)Pr(2))(THF), 1; LZn(N(i)Pr(2)), 2; LMg(O(t)Bu)(THF), 3; LZn(O(t)Bu), 4; and LZn(OSiPh(3))(THF), 6; where L = CH(CMeNC(6)H(3)-2,6-(i)Pr(2))(2). Their dynamic solution behavior has been examined by vari…
Cluster physics is the foundation of the increasingly important field of nanotechnology. Clusters, ranging in size from a few to many millions of atoms, constitute a fascinating field of research in physics, chemistry and materials science. They are formed by most of the elements of the Periodic Table, and the types o…
It is now widely accepted that the magnetic transition in doped manganites that show large magnetoresistance is a type of percolation effect. This paper demonstrates that the transition should be viewed in the context of the Griffiths phase that arises when disorder suppresses a magnetic transition. This approach expl…
ADVERTISEMENT RETURN TO ISSUEPREVNoteGelation and Development of Liquid Crystalline Order during Cure of a Rigid-Rod EpoxySeunghyun Cho and Elliot P. DouglasView Author Information Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 Cite this: Macromolecules 2002, 35, 11,…
Abstract Poly[bis(glycine ethyl ester)phosphazene] (PGP) was blended with poly( D,L ‐lactide‐ co ‐glycolide) (80:20 by mole) (PLGA) and poly[sebacic anhydride‐ co ‐trimellitylimidoglycine)‐ block ‐poly(ethylene glycol)] (30:50:20 by mole) (PSTP) in various ratios using a solvent‐mixing technique. The in vitro degradat…
Surface topography is believed to be a factor affecting cellular morphology, proliferation, and differentiation. The effect of surface roughness in the micron to supramicron range has been investigated previously. In the current study, the influence of nanoscale surface roughness was examined in terms of its effects o…
The application of reaction calorimetry and process modelling to allow for the rapid and safe scale-up of a Vilsmeier formylation reaction to the pilot plant will be described. This transformation was a key step in the preparation of the backbone amide linker (the so-called “BAL” handle) for solid-phase chemistry. In…
We have measured electron emission from ${\mathrm{C}}_{60}^{\ensuremath{-}}$ ions in a storage ring. The ions were produced at room temperature and excited by absorption of photons with a total energy of 14 eV. The observed lifetime $(\ensuremath{\sim}0.6 \mathrm{ms})$ is consistent with detailed balance and a cross s…