Materials Literature
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Abstract It is shown that the covering approach with a single decagonal prototile can be transformed into a hexagon, boat and star tiling. Particularly, the atomic decoration recently proposed by Cockayne and Widom (Phys. Rev. Lett. 81 (1998) 598–601) as a structure model for the decagonal phase is investigated. There…
Experimental-theoretical studies were carried out of the electrical and magnetic properties of the antiferromagnetic semiconductor Cr 0.5 Mn 0.5 S in the temperature range 4.2–300 K. A magnetic antiferromagnetic-ferrimagnetic phase transition was observed along with a semimetalsemiconductor electronic transition. Mont…
Different batch cooling modes (quick and slow cooling with constant cooling rate, program-med cooling with nearly constant supersaturation) of copper sulphate aqueous solutions have been studied in order to find best conditions for the investigation of the effect of additives on crystallization. Three types of additiv…
An electrical-conducting polypropylene/polypyrrole (PP/PPy) composite was prepared by the chemically oxidative modification reaction of pyrrole on the surface of PP particles in suspension. Another type of PP/PPy composite was prepared by mixing the coated PP particles with noncoated PP particles at room temperature.…
The objective of this study is to formulate a simple, rational model for estimates of the penetration depth of rigid long rods through materials susceptible to microcracking. The proposed is based on the target resistance estimated using the particle dynamic simulations. All material parameters of the model can be ide…
Abstract Montmorillonite was modified by replacing the exchangeable cations with betaines (CH 3 ) 3 N + - (CH 2 ) n - COO - M + (n = 3, 5, 7, 10) The betaine derivatives delaminated in water and formed a colloidal dispersion. Air-drying of this material yielded hard pieces which were difficult to redisperse. The dried…
Polytetrafluoroethylene powder (PTFE) was exposed to electron beam radiation in presence of air. The irradiation mainly resulted in chain scission and induction of oxygenated groups and radicals as well as unsaturation. The thermal behavior of the irradiated PTFE and the fate of the radicals were studied comprehensive…
A promising technique for the fabrication of mullite ceramics and mullite‐matrix composites with low dimensional changes (“near‐net‐shape processing”) is reaction bonding using Si metal and α‐Al 2 O 3 as starting materials, because sintering‐induced shrinkage is compensated by Si‐oxidation‐induced volume expansion. A…
Simulations have been performed at 480 K for pure melts of atactic, isotactic and syndiotactic polypropylene chains with a degree of polymerization of 50 and composition C150H302, and also for the three 50:50 mixtures of two of these species. The simulations are performed on a high coordination lattice, with incorpora…
Two dynamical thermokinetic systems for simultaneous reaction models of polymer decomposition are compared. In the independent-parallel model, the common reactant is divided explicitly between the reactions, and in the competitive model the entire reactant mass is available to both reactions. Elementary bifurcation an…
Cet article fait le point sur les connaissances concernant l'implication des bactéries sulfurogènes dans la corrosion des aciers au carbone. Après la description de quelques cas récents tirés de l'industrie pétrolière, la physiologie des bactéries sulfurogènes qui jouent le rôle principal dans le mécanisme de la corro…
The fatigue of copper single crystals, orientated for single slip, has been studied using electron channelling contrast imaging in a scanning electron microscope. With the incident beam set at the Bragg condition, changes in the backscattered electron intensity occur as the beam is scanned over dislocations that cause…
Abstract For 40 years the copper polysilicate Cu[SiO 3 ], isotypic with the germanate prototype Cu[GeO 3 ], was considered non-existent. Recently however we discovered this compound as a metastable decomposition product of the silicate mineral dioptase, Cu 6 [Si 6 O 18 ] · 6 H 2 O. Its orthorhombic unit-cell was refin…
New aromatic diamines [(1) and (2)] containing polycycloalkane structures between two benzene rings were synthesized by HCl-catalyzed condensation reaction of aniline hydrochloride and corresponding polycycloalkanone derivatives. The structures of diamines were identified by 1H-NMR, 13C-NMR, FTIR spectroscopy, and ele…
Abstract Raman spectra of a selection of kaolins with widely varying TiO 2 contents revealed the presence of anatase in 17 of 18 samples. A significant positive correlation was observed between the intensity of the main anatase Raman band at ~145 cm -1 and the total TiO 2 contents of the kaolins as determined by chemi…
A new approach to the development of the nonlinear moment method for solving the Boltzmann equation is advanced. The approach is based on the invariance of the collision integral with respect to the choice of basis functions. It is shown that the matrix elements corresponding to the moments of the nonlinear collision…
Abstract The effect of numerous reprocessing cycles on transport properties of isotactic polypropylene ( i PP) films was studied and related to the change of molecular weight and molecular weight distribution occurring during the recycling. Sorption curves of dichloromethane vapor in different samples of i PP were ana…
Binary solid solutions of the system x Pb(Fe 1/2 Nb 1/2 )O 3 –(1- x ) Pb(Zn 1/3 Nb 2/3 )O 3 were synthesized by the conventional ceramic process, where the constituent Pb(Zn 1/3 Nb 2/3 )O 3 ceramic is not ferroelectric, having a pyrochlore structure. For highly dense ceramic specimens with varying compositions, variou…
The mode of microscopic deformation during impact testing of a 80/20 PMMA/rubber blend has been examined by in situ small-angle X-ray scattering using synchrotron radiation. As discussed previously, the blend studied possesses an extremely small dispersed rubber phase prepared via chemically induced phase separation a…
The effect of boron chloride formation from zinc borate in burn ing PVC was elucidated. By thermodynamic calculation, experiment, and infra red spectrum analysis, the conditions for boron halide formation when PVC was burned were addressed. It is found that when boron halide is produced, the B 2 O 3 glass layer is des…