Materials Literature
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Molecular dynamics is used to simulate nematic liquid crystal structures confined to a submicron cylindrical cavity. Molecules, fixed at the lattice points, are set to interact via a modified induced-dipole--induced-dipole type coupling. Stability regions of characteristic nematic structures are determined as function…
Abstract Characteristics of aged polymers intended for material recycling are emphasized. Specific material properties of aged recyclates, containing new functional groups formed during processing and first‐life application (structural polymer inhomogeneities) and metallic compounds, pigments or compounds generated fr…
In the hopes of helping the discovery of a really biaxial nematic phase in the thermotropic liquid crystal family, we give a brief review on the experimental methods available for proving biaxiality in oriented or disoriented samples. We discuss the relative advantages and problems that arise with the biaxial tests ba…
Abstract In this paper, I provide a theoretical basis for a practical approach to measuring the pressure field of an air gun array and present an algorithm for computing its wavefield from pressure measurements made at known positions in the vicinity of the gun ports. The theory for the oscillations of a single bubble…
Large ATP-dependent proteolytic complexes carry out the majority of intracellular proteolysis. To begin to understand the function of these proteases at a structural level, we have combined the information from a number of biophysical techniques such as electron microscopy (EM), small-angle scattering, and x-ray cryst…
In this paper, a new calculation method of the atomic flux divergence used to predict the formation of electromigration-induced void is proposed by considering two-dimensional distributions of current density and temperature and also simply considering the line structure of not only polycrystalline, but also bamboo li…
The unsolved problem of plastic waste utilization has led to a great interest in the development of studies of accelerated degradation of polymers. In this work the course of photo-oxidative degradation of some water soluble polymers such as poly(acrylic acid) (PAA), poly(methacrylic acid) (PMA) and poly(vinylpyrrolid…
Although NiO is often considered the classic example of an antiferromagnetic insulator, recent investigations have revealed unexplained features of the magnon spectrum. The present study of the temperature and polarization behavior of first-order magnetic Raman scattering reveals that the polarization selection rules…
New liquid crystalline 1,3,5-triazines are presented that incorporate three mesogenic groups based on rod-like azobenzene moieties. The synthesis was carried out by reaction of cyanuric chloride with 4-alkoxy-4-aminoazobenzene derivatives. The mesomorphic behaviour was investigated by polarizing microscopy, differenti…
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…