Materials Literature
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ZnS thin films were deposited with and without ion assisted deposition onto substrates held at temperatures ranging from -120 to 50 degrees C. Effects on chemical and crystalline composition, film microstructure, refractive index, stress, and waveguide losses were investigated. We observed that minimum stress and mini…
With an ultralow load indenter the hardness H and the Young’s modulus E of amorphous hydrogenated carbon and silicon films, prepared under different conditions, were determined. The values of the hardness of a-C:H, corrected for the elastic recovery, are about 1/3 of the values measured by the Knoop method. The result…
We show by transport properties and electron-microscopy measurements that a polytype of ${\mathrm{NbS}}_{3}$ undergoes a Peierls transition at 340 K. Similarly to other transition-metal trichalcogenides and tetrachalcogenides, ${\mathrm{NbS}}_{3}$ exhibits charge-density-wave transport for temperatures below the phase…
Nematic LC material in the aligned state scatters light strongly, but in low loss LC cored fiber waveguides it scatters less and has enhanced recovery time.
The equilibrium segregation at symmetric twist grain boundaries in Ni-Cu alloys is computed with use of Monte Carlo simulations combined with the Daw-Baskes embedded-atom method. These simulations include both compositional rearrangements and atomic displacements. The boundaries studied are the \ensuremath{\Sigma}5, \…
The loss rate O2(a 1Δg) on a variety of surfaces has been investigated. At 300 K, the most rapid deactivants are Cu, Ag, and Co, with Fe, Ni, Pt, and Pd being somewhat less active. Numerous metals exhibit very low activity, including Al, Au, and W. Quite different temperature dependences were observed among the metals…
Neutron powder-diffraction measurements have been performed on polycrystalline lithium and sodium specimens at 80 and 20 K and on potassium metal at 80 and 10 K. Lithium is bcc (body-centered cubic) at room temperature and undergoes a martensitic structural phase transformation to a 9R (samarium-type) form at low temp…
Grain-oriented films of VO2 have been prepared to characterize the effects of film orientation on electrical and optical switching performance. This oriented growth has been achieved by lattice matching to (0001) sapphire, and results in intergranular structures favorable to rapid propagation of the monoclinic-tetrago…
Several properties associated with the field-induced phase change between the antiferroelectric and ferroelectric states in tetragonal (Pb0.97 La0.02 )(Sn,Ti,Zr)O3 antiferroelectric ceramic family were investigated for high-strain displacement transducer applications. The longitudinal field-induced strain accompanying…
ZnS cristallise dans P6 3 mc avec a=8227 et c=6,2607 A, Z=2; affinement jusqu'a R=0,017. ZnO cristallise dans P6 3 mc avec a=3,2501 et c=5,2071 A, Z=2 affinement jusau'a R=0,012. Les atomes Zn occupent la position speciale 2(b) avec les coordonnees 1/3, 2/3, Os et O occupent egalement la position speciale 2(b) avec le…
NaOH solution has been used to study the dissolution rates on boron-doped Si(100) wafers as a function of molarity (0.02 to 10 M) and temperature in the range from 30 degrees C to boiling point. For dissolution at boiling point, two distinct ranges of solution normalities have been observed. For M<or=4.5, the dissolut…
Abstract Plastic deformation in a structurally well-relaxed two-dimensional atomic glass was simulated by a computer molecular dynamics approach. The simulation, which was carried through yielding and to substantial plastic strains, demonstrated that the principal mechanism of plastic strain production is by local par…
Previous theories of the inertial contribution to measured stress in dynamic compression of cylindrical specimens have been extended to allow for anvil motion as well as specimen strain. A numerical model has been developed to estimate the inertial stress from this theory, and it was found that the new term can have t…
Changes in the properties of polymer materials caused by absorption of high-energy radiation result from a variety of chemical reactions subsequent to the initial ionization and excitation. A number of experimental procedures may be used to measure, directly or indirectly, the radiation chemical yields for these react…
Changes in the properties of polymer materials caused by absorption of high-energy radiation result from a variety of chemical reactions subsequent to the initial ionization and excitation. A number of experimental procedures may be used to measure, directly or indirectly, the radiation chemical yields for these react…
ChemInformVolume 20, Issue 50 Physical Inorganic Chemistry ChemInform Abstract: A Structural Study of 12 H-BaFeO2.93 M. PARRAS, M. PARRAS Dep. Quim. Inorg., Fac. Cienc. Quim., Univ. Complutense, E-28040 Madrid, SpainSearch for more papers by this authorM. VALLET-REGI, M. VALLET-REGI Dep. Quim. Inorg., Fac. Cienc. Quim…
A taxonomic study of the benthic marine diatoms from Caja de Muertos Island is reported in this paper. One hundred eighty-five taxa were observed. Twenty-one of these taxa represent new records for Puerto Rico and twenty-two taxa are new records for the Caribbean Sea. The genera represented by the greatest number of t…
We introduce a microscopic model for the phase separation in block copolymers and carry out Monte Carlo simulations in two dimensions. We find that the equilibrium structure function satisfies a scaling relation with ${D}_{\mathrm{eq}}$, the thickness of the microdomains. We also find that ${D}_{\mathrm{eq}\mathrm{\en…
The authors have calculated the phonon dispersion curves of barium titanate (BaTiO 3 ) in the cubic phase. A nonlinear shell model is used, in which the fourth-order anharmonic core-shell interaction of the oxygen ion is considered within a self-consistent phonon approximation. The temperature dependence of the ferroe…
The use of obliquely SiO evaporated glass plates at grazing incidence and controlled thickness gives a surface twofold degenerate oblique orientation for the nematic liquid-crystal MBBA (p-methoxy-benzylidine-p-n-butyl-aniline). Using a horizontal electric field and the linear flexoelectric coupling, one can switch th…