Materials Literature
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Abstract The vinylation of cellulose by acetylene under alkaline conditions was optimized with respect to both DS and DP. Shortening the reaction time reduced the harmful alkaline depolymerization of cellulose during the reaction and gave products with higher DP values. Thus cellulose, activated by KOH, was vinylated…
The authors report a photoluminescence study of the 811 meV no-phonon line structure in platinum-doped silicon. Zeeman and piezospectroscopy measurements show that the centre responsible for the luminescence has C 2v symmetry. The transition is tentatively identified as occurring between internal levels of substitutio…
Abstract The absorption diffusivity of dicumyl peroxide (DICUP) in low density polyethlene pellets that have been annealed and either cooled slowly or quenched has been measured and correlated with the corresponding changes in crystallinity as measured by DSC. Annealing at 125°C resulted in an increased crystallinity…
Abstract A range of hydroxy‐terminated polymyrcenes has been prepared using hydrogen peroxide initiated polymerization of pyroysate grade, β‐myrcene in n ‐butanol solution at 100°C. An oligomeric fraction, containing a large proportion of dimeric material formed via the Diels–Alder reaction, always accompanies the maj…
X-ray scattering experiments have been carried out in order to investigate the mechanism of the phase transitions in CsSnBr 3 . The perovskite crystal CsSnBr 3 undergoes three successive phase transitions at T=19, 1 and -26 degrees C. The crystal symmetry sequentially transforms from cubic to tetragonal to tetragonal…
Abstract Intensity modulated photocurrents have been analysed in order to investigate the kinetics of surface recombination processes, and the theoretical response expected for different types of surface potential distribution are derived and compared with experimental results.
Abstract Thin films (0.05–0.08 mm thick) of stabilized and unstabilized polypropylene were aged under 4.24 MPa (614 psi) of oxygen at 90°C. The oxidation of these films was monitored using transmission infrared spectroscopy. Previously it was shown that embrittlement for the thin unstabilized polypropylene films occur…
The stability of icosahedral, pentagonal, and other quasicrystalline phases to deformations which make them commensurate, and thus periodic, in one or more directions is analyzed. Although such deformations may be arbitrarily small, it is shown that quasicrystals are generically stable to them. Quasicrystals may there…
Optical properties of de sputtered indium tin oxide (ITO) films are studied in the range of photon energies 0.7 to 4.5 eV. The data are analysed in the light of existing theories indicating Burstein- Moss shift. Correlation among carrier concentration, plasma frequency, and optical band gap indicates an effective mass…
The spontaneous magnetization and the coercive field of sintered Sm(Co, Fe, Cu, Zr)7.6 alloys of cellular microstructure which were annealed at 775°C (sample A1) and also at 400°C (sample A2), were measured in the temperature range between 4.2and 1200 K. Materials A1 show an intrinsic type magnetic hardness with expon…
A comparison of photoemission and inverse photoemission results on NiO and NiS shows that the optical gap in NiO can consistently be interpreted as a p→d transition.Received 19 August 1985DOI:https://doi.org/10.1103/PhysRevB.33.7267©1986 American Physical Society
Elastic properties of holmium vanadate, HoVO 4 , have been investigated by means of an ultrasonic method. The elastic constants C 11 , ( C 11 - C 12 )/2 and C 66 exhibited remarkable softenings possessing minimum points around 13.5 K, which are characterized by the quadrupolar responses for the singlet ground state sy…
A lattice dynamical model is constructed for the NaCl type alkali halide crystals by incorporating the covalency effects in the framework of Hardy's polarization dipole model. Three effects of covalency are taken into account: (1) the reduction of the effective charge of the long range Coulomb interaction between ions…
Measurements of tracer (self-) diffusion coefficients of H in the body-centered-cubic \ensuremath{\alpha}' phase of ${\mathrm{VH}}_{\mathrm{x}}$ are reported for hydrogen concentrations x=0.17 to 0.68 and temperatures from 435 to 620 K. Experimental results, obtained from the NMR alternating-pulsed-field-gradient spin…
The electronic structures of ${\mathrm{ZrC}}_{\mathrm{x}}$, ${\mathrm{ZrN}}_{\mathrm{x}}$, ${\mathrm{NbC}}_{\mathrm{x}}$, and ${\mathrm{NbN}}_{\mathrm{x}}$ for several concentrations x were investigated by means of the Korringa-Kohn-Rostoker coherent-potential approximation and the Korringa-Kohn-Rostoker Green's-funct…
The dynamic structure factor S(q,\ensuremath{\omega}) of electrons in Li-metal single crystals for q\ensuremath{\parallel}[100], q\ensuremath{\parallel}[110], and q\ensuremath{\parallel}[111] with 0.28 a.u. <q<1.4 a.u. was measured with 1-eV resolution by using inelastic scattering of synchrotron x radiation fro…
Three types of amorphous-titania films prepared by ion- and electron-beam techniques have been annealed thermally. An amorphous-crystalline transformation is found in each of these film types at around 350 °C. Its resulting microcrystalline structure and the exact transition temperature appear to be dictated by the ru…
Crystal–melt interfaces at the triple point have been investigated by molecular dynamics techniques. The face–centered-cubic (111), (100), and (110) orientations were simulated using a modified Lennard-Jones potential between particles. Comparisons of structural and dynamic properties are made. Profiles measured throu…
We find a systematic procedure constructing the 2D and 3D " periodic " Penrose tilings, which tend to the infinite Penrose tilings. The electronic states in the 2D Penrose tiling are studied by using this sequence. We observe that the spectral measure is singular continuous in the limit of the infinite size. Most of e…
The calculated results of the orbital susceptibility for first- to fifth-stage graphite intercalation compounds (GIC's) are presented. In this calculation a new formalism for calculating the orbital susceptibility is presented. Furthermore, in order to perform calculations in an analytical way, the effective Hamiltoni…