Materials Literature
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A negative allosteric effect is observed in the [2]pseudorotaxane incorporating the 1,5-dioxynaphthalene derivative stoppered at one end by the [18]crown-6 macrocycle when it binds alkali metal cations. This effect can be exploited to elicit an optical response that can be monitored by UV spectroscopy. The principle i…
Photon-excited B K fluorescence spectra were measured for hexagonal boron nitride using tunable synchrotron radiation below and above the B K edge. We report Raman-like resonant inelastic scattering of soft x rays involving excitation of delocalized valence-band electrons. The inelastic scattering features track with…
A single multiwalled carbon nanotube with an outside diameter of about 12 nm and an inside diameter of about 4 nm has been isolated in order to measure its electrical properties (resistivity, transverse magnetoresistance and temperature dependence of resistance). The semi-metallic character of the conductance of the s…
In situ x-ray diffraction studies were performed on the PLSnZT antiferroelectric–ferroelectric phase switching ceramic and polycrystalline powder. The crystallography of both the antiferroelectic and electric-field-induced ferroelectric phases were determined for the approximate composition of Pb0.98La0.02(Zr0.55Sn0.3…
Neutron diffraction measurements on the title compounds have been carried out over a range of temperature from 10 to 300 K. The compounds have a rhombohedrally distorted perovskite structure. A paramagnetic to ferromagnetic transition is observed for samples with . The ordered magnetic moments obtained for x = 0.2 and…
By using the cold plasma torch we developed, TiO2 films were deposited on substrates exposed to air by feeding Ti(OEt)4 into the plasma. XPS and x-ray analyses revealed that all films were stoichiometric and amorphous TiO2, but Raman spectra indicated the existence of short-range crystallinity in films deposited above…
Neutron scattering has been used to study the magnetic correlations and long wavelength spin dynamics of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ in the ferromagnetic regime $(0\ensuremath{\le}x<\frac{1}{2})$. For $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\frac{1}{3}$ $({T}_{…
Transfer of MPEG(1900)-DSPE from micellar phase to pre-formed liposomes imparts long in vivo circulation half-life to an otherwise rapidly cleared lipid composition. MPEG(1900)-DSPE transfers efficiently and quickly in a time and temperature dependent manner. There is negligible content leakage and a strong correlatio…
The drainage of liquid in a foam may be described in terms of a nonlinear partial differential equation for the foam density as a function of time and vertical position. We review the history and recent development of this theory, analysing various exact and approximate solutions and relating them to each other.
The nonlinear optical crystal KBe2BO3F2 has been used to produce vacuum ultraviolet second-harmonic generation with an output range of 200–184.7 nm. The Sellmeier equation further indicates that this new crystal can generate the sixth harmonic from Nd-based laser systems.
The antiferromagnetic to ferromagnetic transition in L${\mathrm{a}}_{0.5}$C${\mathrm{a}}_{0.5}$Mn${\mathrm{O}}_{3}$ is accompanied by a commensurate to incommensurate charge-ordering transition. The presence of incommensurate charge correlation in the ferromagnetic phase is a remarkable interplay between charge and sp…
The stability of Ne@C$_{60}$ and He@C$_{60}$ is discussed in the context of a spherical model where the carbon atoms are smeared out into a uniform shell. The electronic properties of the sixty $π$ electrons together with those of the central atom are treated in the Thomas-Fermi approximation. Simple electrostatic rea…
Bales of antioxidant-stabilized guayule rubber underwent significant losses in bulk viscosity when stored under ambient conditions at an Arizona processing facility. Previous work implicated the unsaturated fatty acid esters present in entrained resin as promoters of such degradation. Aging studies as functions of sto…
Dielectric and dilatometric investigations of (NH2(CH3)2)2CoCl4 crystals were performed in the temperature range 290 to 430 K. Anomalies characteristic of phase transitions have been found at the temperatures 419, 380, 353, and 313 K (in a heating run). In certain phases the investigated crystal shows anomalously high…
The Al-Ni-Fe decagonal quasicrystalline phase is thermodynamically stable between about 847 and 930 °C. The features of its transformation below 847 °C into three neighboring crystalline phases (Al13(Fe, Ni)4, Al3Ni2(Fe), and Al3Ni(Fe)) are reported.
Composite films of ZnS and SiO2 were prepared by co-evaporation from two separately controlled sources. Pure ZnS films were found to consist of crystallites with mean diameter between 10 and 15 nm for films thicker than about 100 nm. The addition of SiO2 to ZnS seems to be very efficient in reducing crystallinity and…
Clear time (tcl), the time required for the turbid mixture of terephthalic acid (TPA) and ethylene glycol (EG) to be clear, was measured to examine the effect of poly(ethylene terephthalate) (PET) prepolymer (DP of 1–5) on the kinetics of dissolution and/or ester-ification of TPA with EG. The tcl of the mixture of TPA…
When isotactic polypropylene is quenched at 0°C from the molten state, a biphasic material, amorphous-smectic, is obtained. The smectic phase has an intermediate order between the amorphous and the crystalline. In this study the intrinsic birefringence of the smectic phase was determined. Tapes with different draw rat…
Sorption and diffusion of benzene and methyl-substituted benzenes were investigated through natural rubber reinforced with four types of carbon black: superbrasion furnace, intermediate superabrasion furnace, high-abrasion furnace, and semireinforcing furnace. The rubber loaded with superabrasion furnace took the lowe…
Anharmonic decay rates are calculated for a realistic atomic model of amorphous silicon. The results show that the vibrational states decay on picosecond timescales and follow the two-mode density of states, similar to crystalline silicon, but somewhat faster. Surprisingly little change occurs for localized states. Th…