Materials Literature
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The starting mechanisms and dynamics of laser-induced bubble formation at a submerged fiber tip in distilled water were experimentally investigated using pressure measurements and fast flash videography. A fiber guided Ho:YAG laser operating in the free running (τ=200 μs) and Q-switched (τ=45 ns) mode at a wavelength…
The WLF approach is appropriate for lifetime predictions when polymer ageing is controlled by a viscoelastic process (relaxation, creep). This methodology using time/temperature shift will be illustrated by the creep of SBR/NR. When physico-chemical mechanisms are dominant, the Arrhenius approach is the most widely us…
The long-range interface correlation in thin polymer films (polystyrene and fully brominated polystyrene) prepared by spin-coating is examined. Using diffuse X-ray scattering at small angles of incidence, the roughness correlation which dominates the surface morphology of the polymer film is probed from mesoscopic dow…
Enzyme-catalyzed ring-opening polymerization of a cyclic phosphate (ethylene isopropyl phosphate) was achieved in bulk by using porcine pancreas lipase (PPL) as a catalyst. It was found that the higher the polymerization temperature and lipase concentration, the faster is the polymerization rate. The yield is not very…
Abstract This paper describes plastic foam processing for the manufacture of LLDPE foams in rotomolding. In order to better understand the mechanisms of foaming, a fundamental study on the foaming process in rotomolding has been conducted. First, the decomposition behavior of the chemical blowing agents was studied by…
A study was made of the copper corrosion rate and corrosion products originated by the action of acetic acid vapor at 100% relative humidity. Copper plates were exposed to an acetic acid contaminated atmosphere for a period of 21 days. Five acetic vapor concentration levels were used. The copper corrosion rate was in…
By considering a Hamiltonian that includes the crystalline electric field and exchange interaction components we showed theoretically that paramagnetic ${\mathrm{PrNi}}_{5}$ exhibits an anomalous entropy behavior in which the magnetic entropy increases with increasing magnetic field at low temperature. This anomaly in…
The crystal structure of 2-pyridone has been redetermined from high-resolution X-ray data collected at 123 K. The molecule is in the lactam form. Bond lengths (corrected for rigid-body libration) and angles have been determined with s.u.'s of 0.001 A and 0.1 degree, respectively. The hydrogen-bonded cyclic dimers whic…
The previously reported reaction of phthalocyanines [H2(pc)] with PBr3, which was claimed to give a phosphorus(III) phthalocyanine “(PcPIII)”, has been reinvestigated in detail with both unsubstituted and alkyl-substituted phthalocyanines, 1-4. The products exhibit unusual electronic and mass spectra compared to norma…
Composite materials can be regarded as structures, so there is a great opportunity to design a wide range of properties for such kind of material to meet the various application requirements, even a very particular one. A negative Poisson's ratio is an example. The mechanism of negative Poisson's ratio and the basic c…
General guidelines for the design of monomers for the synthesis of hyperbranched polymers without linear units are presented. The synthesis of one monomer fulfilling these requirements and the first results of the polymerization of this monomer are described. 4-(3-Maleimidopropoxy)-4′-methoxybenzaldehyde azine was use…
In an attempt to obtain dense PbNb 2 O 6 ceramics, sintering experiments were conducted using starting powders with various particle sizes and different modifications (rhombohedral and orthorhombic structures). During sintering of rhombohedral powders, the phase transformation to the tetragonal phase promoted grain gr…
Stereoregular polymerization of ( p -nitrophenyl)acetylene (pNPA) was performed using [Rh(norbornadiene)Cl] 2 and [Rh(cyclooctadiene)Cl] 2 catalysts to give poly(( p -nitrophenyl)acetylene) (PpNPA), with a cis−transoid form under mild conditions. The polymer underwent isomerization from the predominant cis to trans fo…
A nitrogen purged static-bed batch reactor was used to pyrolyse 3 kg batches of shredded scrap tyres at temperatures between 450 and 600 °C. The yield of char remained fairly constant at about 38 wt% irrespective of pyrolysis temperature; however, the yield of oil decreased from 58 wt% to 53 wt% and the gas yield incr…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTMechanisms of Surface Electron Transfer. Proton-Coupled Electron TransferScott A. Trammell, John C. Wimbish, Fabrice Odobel, Laurie A. Gallagher, Poonam M. Narula, and Thomas J. MeyerView Author Information Department of Chemistry University of North Carolina at Chapel…
〈111〉-oriented twin free Tb–Dy–Fe single crystals, 〈112〉- and 〈110〉-oriented twinned “single” Tb–Dy–Fe crystals were prepared using floating zone melting technique. Magnetostrictive performances of the crystals were investigated. Better low-field properties were observed in the 〈110〉 twinned crystals than in the 〈112〉…
Summary The plant availability of phosphate applied to calcareous soils is affected by precipitation and adsorption reactions, the relative significance of which is not well known. We used extended P‐sorption curves obtained at phosphate addition rates up to 340 mmol P kg −1 soil to examine the relative contribution o…
The objective is to define a prediction and transposition model for cavitation erosion. Experiments were conducted to determine the energy spectrum associated with a leading edge cavitation. Two fundamental parameters have been measured on a symmetrical hydrofoil for a wide range of flow conditions: the volume of ever…
The ground state total energies of α‐ and β‐Si 3 N 4 crystals are calculated by an ab‐initio method based on local density functional theory. The calculated bulk modulus and pressure coefficients for both crystals are in good agreement with recent experimental measurements. Interatomic pair potentials of the Buckingha…
The crystal structure of NiII2(mcpa)2(CH3OH)3(H2O)[12-MCNiIIN(shi)2(pko)2-4][12-MCNiIIN(shi)3(pko)-4] metallacrown shows it to have a fused arrangement of two [12-MCM(ox)N(ligand)-4] units, the NiII(mcpa)[Ni4(shi)2(pko)2(CH3OH)2] and the NiII(mcpa)[Ni4(shi)3(pko)(CH3OH)(H2O)] with 1+ and 1− charge, respectively. Each…