Materials Literature
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Large ferrite cores used in high-power, high-frequency applications can experience dimensional effects that limit the bandwidth of the device and cause losses higher than those predicted by manufacturer's datasheets. This paper examines such effects in Mn-Zn cores of various sizes and presents corroborating measuremen…
Abstract Our results from structural investigations of transition metal complex ion pairs in solution by homonuclear and heteronuclear 1D‐ and 2D‐NOE NMR spectroscopy are reviewed. Both model ( A ) and catalytically active ( B ) complexes have been taken into account; their general formulas are: trans ‐[ML 2 (N,X)(Y)(…
Infrared microscopy has been used to measure the thermal conductivity K of printed wiring boards with embedded layers of Cu, for heat flow perpendicular (K/sub /spl perp//) to the plane of the board. The technique provides the thermal conductivities of the individual glass-epoxy layers and the thermal resistance at ea…
In many power electronic applications, ferrite cores of magnetic components are biased with a DC or low-frequency premagnetization. Usually however, the influence of the bias on the losses and permeability is not considered in the component design. This paper describes a precise measurement setup to determine the powe…
Abstract The effects of resin molecular weight on the flame‐retardant mechanism of silica were studied with two different molecular weights of poly(methyl methacrylate) (PMMA), 122,000 and 996,000 g/mol, and two silicas, fused silica with a small surface area and silica gel with a large surface area. A total of six di…
Cobalt and Co80Ni20 metal particles were prepared by reduction of acetate salts in a liquid polyol. The relative amount of the hcp phase and the probability of stacking faults in this phase vary with the experimental conditions of synthesis. The formation of either isotropic or anisotropic particles appears to be clos…
Taking into account the temperature gradients in solar cells, it is shown that their efficiency can be increased beyond the Shockley-Queisser limit (J. Appl. Phys. 32 (1961) 510). The driving force for this gain is the temperature gradient between this region and its surroundings. A quantitative theory is given. Thoug…
MgB2 samples prepared by solid-state reaction were investigated using high-resolution transmission electron microscopy (HREM), X-ray energy-dispersive spectroscopy (EDX), electron energy-loss spectroscopy (EELS), and energy-filtered imaging. Large amounts of coherent precipitates with a size range from about 5 nm up t…
The pressure - temperature phase diagrams of Se and S are calculated. Both melting and polymorphous phase transition are described in the frames of statistical Patashinski model. The results are in good agreement with experimental data of Brazhkin et. al.
Topography of silicon surfaces irradiated by a 2 MeV Si$^+$ ion beam at normal incidence and ion fluences in the range $10^{15}-10^{16}$ ions/cm$^{2}$ has been investigated using scanning tunneling microscopy. At length scales below $\sim$~50 nm, surface smoothing is observed; the smoothing is more prominent at smalle…
In this paper we present the results on Raman-active modes calculation in achiral $(n,n)$ and $(n,0)$ carbon nanotubes (CNTs). vibrational spectra are derived as the eigenvalues of corresponding dynamical matrix at the $Γ$-point of Brillouin zone. Diagonal components and $α_{xy} (=α_{yx})$ are the only non-zero compon…
The switching kinetics in ferroelectric thin films has been intensively studied during the past decade. It is widely accepted that this kinetics is basically governed by the dynamics of domain coalescence (the Kolmogorov-Avrami-Ishibashi model). This conclusion is mainly supported by fitting the time dependence of the…
In this paper, the average unit cell for a quasicrystal is constructed by a statistical approach. For the Penrose tiling, it is shown that such a unit cell is fully equivalent to the oblique projection of the atomic surface onto physical space. The obtained statistical distributions can be easily extended to imperfect…
The radio frequency (RF) plasma-modified surfaces of kaolinite were investigated by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) and deuteration techniques to determine the nature of RF plasma-induced surface functional groups, the altered sites in the lattice, and interaction mechanism between…
State of the art CASSCF and CASPT2 calculations have been performed to elucidate the nature of the electronic transitions observed in the experimental spectrum of the octacyanomolybdate(V) cation. Assuming a triangular dodecahedral structure for this complex gives a convincing agreement between theory and experiment.…
Crystalline modifications α and β of uniaxially oriented poly(tetramethylene naphthalate) [PTMN] sample have been found to show a reversible phase transition, which is induced by an application of a tensile force along the draw axis, as clarified by the measurement of polarized infrared spectra under tension. The tran…
The formation of vesicles during the synthesis of mesostructured surfactant-silicate materials has been evidenced for the first time by applying in situ Cryo-TEM. A mixture of anionic and cationic surfactants was used to fine-tune the packing parameter of the supramolecular surfactant assembly. It is shown that the ve…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSpherulite Morphology of Form III Isotactic Poly(1-butene)B. Lotz and A. ThierryView Author Information Institut Charles Sadron (CNRSULP), 6, rue Boussingault, 67083 Strasbourg, France Cite this: Macromolecules 2003, 36, 2, 286–290P…
The theoretical basics of the analysis of voids in crystal structures by means of Voronoi-Dirichlet polyhedra (VDP) and of the graph theory are stated. Topological relations are considered between VDPs and atomic domains in a crystal field. These relations allow the separation of two non-intersecting topological subsp…
Copper binding properties were investigated for several popular zwitterionic buffers. The two buffers 4-morpholinoethanesulfonic acid (MES) and 3-N-morpholinopropanesulfonic acid (MOPS) did not bind copper and would be good choices for metal speciation studies within their operational pH range. Conversely, 3-(N-morpho…