Materials Literature
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Low-molecular-weight compounds often crystallizes to systems with 100% crystallinity. There are only a few examples where a small amorphous fraction, characterized by a glass transition, remains after long time crystallization from the melt. The crystallization of such a glass-forming low-molecular-weight compound was…
Mullite/Al 2 O 3 functionally graded ceramics (FGCs) have been obtained by sequential slip casting and subsequently firing at 1650°C in air. Functionally graded layered dense (similar/congruent99% of the theoretical density) compacts, with five different layers with thickness ranging from 670 to 850 µm, were obtained.…
Undercooled Nd–Fe–B melts with compositions near the Nd2Fe14B phase (Φ phase) were studied by the electromagnetic levitation technique. In situ measurements of the solidification kinetics were accomplished and melt drops with controlled undercooling were quenched onto chill substrates in order to reveal the solidifica…
When E. coli cells were grown in minimal medium supplemented with D-ribose and D-xylose, a diauxic growth preferring D-xylose was observed. Transcription of the ribose (rbs) operon was repressed in the presence of D-xylose, phenotypically similar to catabolite repression by D-glucose, although D-ribose did not affect…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTAttenuated Total Reflection Fourier Transform Infrared Spectroscopy Study of Poly(methyl methacrylate) Adsorption on a Silica Thin Film: Polymer/Surface InteractionsJean-Marc Berquier and Hervé ArribartView Author Information Laboratoire CNRS Saint-Gobain, "Surface du Verre et…
The use of the reverse Monte Carlo (RMC) technique for analysing diffuse scattering data from single crystals is compared with the well established direct Monte Carlo (MC) method. Whereas in the MC method a model involving only a few interatomic interaction parameters is used, for RMC the atom coordinates themselves a…
Brillouin scattering from transverse-acoustic modes of ${\mathrm{SrTiO}}_{3}$ is observed, while the frequencies of the soft polar modes are remeasured with hyper-Raman scattering. It is shown that an anomalous decrease of sound velocities at low temperatures results from the coupling of the strain with the gradient o…
Using the Green's function and eigenstrain method, we derived an analytical expression for the elastic displacement fields induced by a dislocation in an icosahedral quasicrystal. In this paper, we calculate the special case where the line direction of the dislocation is parallel to a fivefold axis. Combining this exp…
A new hexagonally mesostructured material, constructed from PW11O397− lacunary Keggin anions and surfactant micelles, is reported. The Figure is a schematic representation of the proposed superstructure. The two kinds of hatched circles both represent the anion, the circles with a line attached the surfactant. This ty…
The field dependencies of the magnetization and magnetostriction of the Laves phase pseudobinary TbxDyyHozFe1.95 (x+y+z=1) compounds were measured as a function of compressive stress T (10 MPa<|T|<70 MPa) and applied magnetic field H (0<H<135 kA/m). Values of x, y, and z were chosen to obta…
Using a first-principles method based on density functional theory, we have carried out a study of static properties and vibration frequencies at the $\ensuremath{\Gamma}$ point of cubic and hexagonal diamonds. The bulk modulus and bond length are found to be slightly larger in hexagonal diamond than in cubic diamond.…
Using palladium(0)-catalyzed coupling reactions we were able to synthesize mono-, di-, and trimeric porphyrins linked by di- and trivinylbenzenes. The reactions were carried out with palladium(II) acetate in DMF under phase-transfer conditions. These coupling conditions are new in the field of porphyrin chemistry and…
Pb(Zr,Ti)O 3 films were deposited using DC magnetron multi-target reactive sputtering on Pt/Ti/SiO 2 /Si substrates. The effect of the substrate on the structure of the deposited film was investigated because the nucleation of the perovskite PZT film would be largely affected by the substrate surface conditions. As th…
We present the effect of aluminum substitution on the structure, exchange interactions, and magnetic phase transitions of the intermetallic compound ${\mathrm{Er}}_{2}{\mathrm{Fe}}_{17}.$ All samples have a hexagonal ${\mathrm{Th}}_{2}{\mathrm{Ni}}_{17}$-type structure or a rhombohedral ${\mathrm{Th}}_{2}{\mathrm{Zn}}…
The effect of shear rates on the transcrystallization of polypropylene (PP) on the polytetrafluoroethylene (PTFE) fibers has been quantitatively investigated using a polarized optical microscope equipped with a hot stage and a tensile testing machine. The PTFE fibers were pulled at different rates, from 0.17 to 8.33 μ…
Second-order spin-wave expansions are used to compute the ground-state energy and sublattice magnetizations of the quantum one-dimensional Heisenberg ferrimagnet with nearest-neighbor antiferromagnetic interactions and two types of alternating sublattice spins ${S}_{1}>{S}_{2}.$ It is found that in the extreme quan…
A soluble poly(amic acid) precursor solution of fully rod-like poly(p-phenylene pyromellitimide) (PMDA-PDA) was spin cast on silicon substrates, followed by soft bake at 80–185°C and subsequent thermal imidization at various conditions over 185–400°C in nitrogen atmosphere to be converted to the polyimide in films. Re…
Single crystals of bis(thiourea)zinc chloride, Zn[CS(NH2)2]2Cl2 (BTZC), were grown by slow evaporation of an aqueous solution at room temperature. The crystal has been studied at room temperature by Raman spectroscopy between 20 and 1700 cm—1 and 3000 and 3500 cm—1 and by infrared transmittance in the 400 to 4000 cm—1…
The first steps of the accommodation of extrinsic dislocations in Σ = 3 grain boundaries have been observed in nickel bicrystals. Two types of reaction have been investigated in detail using the weak-beam technique in addition to conventional transmission electron microscopy analyses and the image-matching technique.…
Ion-transport processes in silicate glasses containing alkali and alkaline-earth ions are studied using dynamic mechanical thermal analysis. The mechanical loss spectra are analyzed with respect to the frequency response, the height, and the activation energy of the loss peaks. It is found that the frequency response…