Materials Literature
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Transition metal clusters and colloids of narrow particle size distributions in the range 1-10 nm are currently subject to intense research efforts.1 From a fundamental perspective, the transition from the properties of the bulk to those of molecular clusters is expected to occur in this size range. A transition metal…
Contrary to expectations based on the spectrochemical series, H 2 O is found to be a significantly weaker field ligand than OH - in the magnetochemical series ranking of ligand field strengths based on the spin states of iron(III) tetraphenylporphyrin complexes. The preparation and characterization of the [Fe(H 2 O)(T…
The preparation and molecular structures of several five-coordinate (nitrosyl)iron(II) porphyrinate derivatives are described. The derivatives reported include two crystalline forms of [Fe(OEP)(NO)] (OEP = 2,3,7,8,12,13,17,18-octaethylporphyrin dianion), three conformationally distinct forms of [Fe(TPPBr 4 )(NO)] (TPP…
ABSTRACT: Soy protein isolate (SPI) was utilized as a biopolymer and glycerol was used as a plasticizer to successfully produce light‐yellow, transparent protein films by a thermal compaction technique. Flexible films, approximately 180 micrometers, could be produced at a processing temperature of 150 °C and compactio…
Large-area highly oriented boron carbonitride (BCN) nanofibers with various compositions were synthesized directly on polished polycrystalline nickel substrates from a gas mixture of N2, H2, CH4, and B2H6 by bias-assisted hot-filament chemical-vapor deposition. The morphology of BCN nanofibers was examined by scanning…
Proteins and lipids are capable of interacting in a many different ways to form effective edible films and coatings. Combinations of proteins and lipids function in a variety of colloidal systems such as emulsions and microemulsions. Edible films and coatings can be formed from both of these starting systems. In addit…
We report on susceptibility, magnetization, magnetoresistance, and ultrasonic studies of La 1- x Sr x MnO 3 for x ⩽0.2. The magnetic susceptibilities in the different high-temperature paramagnetic phases are studied in detail. We provide experimental evidence for the occurrence of short-range ferromagnetic order withi…
Internal stresses exist in ZnO varistors as a result of both crystallographic anisotropy in thermal expansion of the constituents and thermal expansion mismatch between phases. Due to the piezoelectric nature of ZnO, these stresses induce a net electric dipole moment that modifies the grain boundary Schottky barriers…
The synthesis of fine powders of electroceramic oxides (e.g., superconductors, dielectrics, and materials exhibiting colossal magnetoresistance) is most commonly carried out by solid-state reaction. Wet chemical methods, which overcome some disadvantages of the solid-state route, are often difficult to scale up. The i…
ABSTRACT: Viscoelastic, thermal, and microstructural properties of plasticized soy protein isolate (SPI) films processed by thermal compaction are discussed. Thermogravimetric analysis indicates that protein films exhibit substantial thermal degradation at temperatures above 180 °C and that the processing temperature…
Azobenzene derivatives are excellent candidates for optical switching systems, due to their facile and reversible photoisomerization. However, the chromophores are usually aggregated in Langmuir–Blodgett films, which suppresses this cis–trans isomerization. Here is reported the anchoring of palmitoyl and azobenzene fu…
We used video microscopy to study the pinning dynamics of air/water contact lines in vertical glass capillaries. Stick-slip behavior and avalanches are observed in tubes with rough interior walls and strong pinning forces. In tubes with smooth interior walls, we find that receding contact lines in falling water column…
A new general procedure to interpret surface-enhanced Raman scattering (SERS) spectra has been developed in order to clarify the controversy concerning the relevant enhancement mechanism of this type of spectra. The analysis consists of detecting the presence of the charge transfer (CT) enhancement mechanism by correl…
Crystalline cerium(IV) oxide nanoparticles with a cubic fluorite structure could be synthesized from cerium(IV) ammonium nitrate solutions with a relatively high concentration of cerium(IV) (such as 0.5 mol/dm 3 ) via thermal hydrolysis at 150°–240°C. The effects of the treatment temperature, the salt concentration, a…
We have studied the temperature dependence of the Raman spectra of ceramic bulk and thin-film samples of polycrystalline ${\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{TiO}}_{3}$ $(x=0,$ 0.1, 0.2, and 0.3) in the range between room temperature and 350 \ifmmode^\circ\else\textdegree\fi{}C. The ferroelectric…
An analysis of the heat capacity data of 21 materials shows that a glass loses 17%–80% of its entropy on cooling from its Tg to 0 K, and that the entropy difference between a glass and crystal phase at Tg, ΔS(Tg), is 1.2 to 4.9 times the entropy difference at 0 K. This is contrary to the premise that the vibrational e…
A study of magnetic and structural properties of (CoxFe100−x)50 (0≦x≦100) alloy thin films as functions of composition and substrate deposition-temperature Ts is carried out. The intrinsic perpendicular magnetic anisotropy Ku starts to increase with deposition temperature Ts for all the films (0≦x≦100) at about TS=250…
Antiferroelectric liquid crystals with a tilt angle of 45 degrees have very interesting optical properties, which seem to have been overlooked so far - perhaps because such materials have hardly been available. We have prepared a four-component mixture of partially fluorinated compounds with a SmCa* phase in the inter…
Methods to characterise the performance of CCD cameras for electron detection are investigated with particular emphasis on the difference between the transfer of signal and noise. Similar to the Modulation Transfer Function MTF, which describes the spatial frequency dependent attenuation of contrast in the image, we i…
Isothermal crystallization of isotactic polypropylene at high pressures (from 200 to 250 MPa) have been carried out using a high-pressure dilatometer leading to a pure γ-form, as revealed by WAXD. The melting temperatures at the same pressures have been determined to assess the pressure effect on the equilibrium melti…