Materials Literature
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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…
Experimental solubilities are reported at 25.0°C for acenaphthene dissolved in 36 different organic nonelectrolyte solvents containing ether-, carbonyl-, hydroxy-, ester, methyl-, and tert-butyl functional groups. Results of these measurements are used to test the applications and limitations of expressions derived fr…
Crystalline WO3−x is an infrared (IR) electrochromic material having possible applications in satellite thermal control and IR switches. Optical constants of electrochromic materials change upon ion intercalation, usually with H+ or Li+. Of primary concern for device design are the optical constants in both the interc…
Novel non-symmetric charge-transfer trimers are presented which consist of an electron-rich penta-alkynylbenzene group with different peripheral substituents and a flat nitrofluorenone acceptor moiety both of which are chemically linked to the terminal positions of a rod-like azobenzene unit. The laterally unsubstitut…
Polyimides were prepared from diamines: 2,4,6-trimethyl-1,3-phenylenediamine (3MPDA) and 2,3,4,5-tetramethyl-1,4-phenylenediamine (4MPDA). 1,4-Bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 3,3'-4,4'-diphenylsulphone tetracarboxylic dianhydride (SO(2)PD…
The band gap and density of state for a form of amorphous diamond synthesized from ${\mathrm{C}}_{60}$ fullerene by shock compression were measured by electron energy-loss spectroscopy in this study. The dielectric functions of the material were derived from the loss function obtained from its spectrum by Kramers-Kron…
Si‐C‐O bulk ceramics with various atomic ratios were produced by pyrolysis and high‐temperature treatment (HTT) of a polycarbosilane (PCS) precursor with a given amount of oxygen. The oxygen introduction within the PCS molecular structure makes the compact infusible during the pyrolysis step, and supports sintering. T…
: A new method for transmission electron microscope (TEM) specimen preparation using a focused ion beam (FIB) system that results in a lower rate of gallium (Ga) implantation has been developed. The method was applied to structural and analytical studies of composite materials such as silicon (Si)-devices and magneto-…