Materials Literature
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The production of molecular hydrogen in the radiolysis of high-density polyethylene by γ rays and heavy ion beams has been investigated. Only the slightest increase in the radiation chemical yield of 3.1 molecules/100 eV was found from γ rays to protons of 5−15 MeV. A gradual increase in yield was observed on further…
We show that the drift velocity of the cholesteric fingers of the second species in ac electric field strongly depends on the conductivity of the liquid crystal chosen and exponentially vanishes above a cutoff frequency we found to be equal (within a numerical factor close to 1) to the charge relaxation frequency of t…
Bi 2 O 3 -based ZnO varistor materials were prepared by 2.45 GHz microwave, 24 GHz millimeter-wave or conventional sintering processes. Both millimeter-wave and microwave sintering processes are superior to the conventional sintering process for densifying Bi 2 O 3 -based ZnO materials. Moreover, the millimeter-wave s…
Behaviors of pretilt angles of liquid crystal (LC) cells were examined using polyimide (PI) films containing fluorine atoms by exposure to ultraviolet light (UV). Using a single obliquely polarized UV exposure, we obtained unidirectional LC alignment with any desired pretilt angles from 0° up to 90°. The pretilt angle…
This work deals with the AC electrical properties measurements under large strain of composites strongly contrasted in the viewpoint of their electrical and mechanical properties. First, the possibility to model a strongly heterogeneous material (from the viewpoint of electrical properties) using an improvement of a R…
The specific heat of a polycrystalline sample of MnO was measured from $T\ensuremath{\approx}1\mathrm{K}$ to $T\ensuremath{\approx}400\mathrm{K}$ using two different experimental apparatuses at zero applied pressure. Features revealed by the data include a hyperfine contribution due to the Mn nuclei, a ${T}^{2}$ tempe…
The influence of alumina content (0‐15 wt% Al 2 O 3 ) on the indentation strength, fracture toughness ( K I c ), and crystal structure of fluorcanasite (Al 2 O 3 ‐CaO‐F‐K 2 O‐Na 2 O‐SiO 2 ) glass‐ceramics was analyzed. Increasing the Al 2 O 3 content from 0 wt% (CAN0) to 8 wt% (CAN8) caused the mean indentation streng…
Oxidation of 4-(1-hydroxy-1-phenylethyl)benzoic acid HPEBA with a water-soluble metalloporphyrin as catalyst and KHSO5 as oxygen atom donor gives the major products, acetophenone AC and acetylbenzoic acid ABA, by a Caliph–CAr bond cleavage, but a minor product, benzoyloxybenzoic acid BOBA, requires the insertion of an…
Developments in electronic area detectors such as CCDs and image plates have transformed the capability of the synchrotron Laue protein crystallography technique compared with film. The rapid readout of CCDs makes practical the use of rather fine angular interval settings of the crystal between each Laue exposure and…
The propagation of the high-spin (HS) → low-spin (LS) relaxation at 53 K in a single crystal of the iron (II) spin-crossover compound [Fe(ptz)6](BF4)2 was followed by photography, after inducing the local photoexcitation to the metastable HS state at 20 K using the single wavelength (457 nm Ar± ion laser) irradiation.…
We present a review of the electronic and non-electronic optical nonlinearities of nematic liquid crystals (NLC), and recently observed nonlinear optical processes. In both the ordered and isotropic phases, NLCs exhibit large optical nonlinearities with response times ranging from picoseconds to milliseconds. The fund…
A mathematical model for interpreting the anisotropical broadening of the powder diffraction lines by an average crystallite in the form of a triaxial ellipsoid is developed. The model covers satisfactorily a broad range of averaged crystallite shapes in polycrystalline samples of all crystal symmetries and provides s…
Cadmium sulfide polycrystalline thin films were grown on glass substrates by the chemical-bath deposition technique (CBD) under application of both a pulsating direct electric and a dc magnetic field acting on the Cd- and S-ions during growth in an aqueous solution which contains CdCl2 and thiourea as source material…
A dc arc discharge was generated between graphite (C) and molybdenum (Mo) electrodes at 25 kPa of He gas ambient for a period of about 1 s in order to reveal the relation between nanotube growth and arc discharge phenomena. Numerous multiwall carbon nanotubes and nanocapsules were observed at the cathode spot area of…
Many of the MR examinations performed in the world each year are accompanied by administration of one of these frequently used intravenous contrast agents: Magnevist, Omniscan, and ProHance. Accordingly, MR practitioners must understand the basic pharmacokinetics, side effects, and the potential for adverse events for…
Abstract Blends of linear low density polyethylene (LLDPE) and linear low density polyethylene grafted with maleic anhydride (LLDPE‐gMA) were used to promote adhesion between LLDPE and ethylene‐vinyl alcohol copolymer (EVOH) in a coextruded three layer flat film, trying to avoid the use of a tie layer. These particula…
We report measurements of the anchoring energy of 5CB (4-cyano-4′-n-pentyl-biphenyl) at a commercial polyimide (AL1051) with a method using a large applied electric field on thick measurement cells. The experiments reveal a deviation from the expected behavior of the system and cannot be described by the usual Frank e…
The clearance of anthracyclines from the vasculature was studied in perfused tissue-isolated tumors. Human tumor lines MCF-7, U87, and LS174T were implanted in the ovarian fat pad of immune-deficient mice and grown isolated from the surrounding tissue. The initial and continuous tissue uptakes of doxorubicin, daunorub…
Structural and vibrational properties are investigated in SiC nanopowders synthesized by a CO2 laser pyrolysis of (SiH4, C2H2) gaseous mixture and thermally treated up to 1800 °C. The structural modifications of the SiC crystallites and the arrangement of the carbon in excess are monitored at different annealing stage…
A method is described for correcting the binding energy scale for specimen charging that occurs during XPS analysis of insulating samples. A small quantity of polymeric poly (dimethyl silicone) (PDMS) is deposited from solution onto the surface of a series of polymers. After XPS analysis, the binding energy scale is t…