Materials Literature
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Optical properties of Eu3+ ions in oxyfluoride glass ceramics and in the precursor glasses (30 SiO2, 15 Al2O3, 29 CdF2, 22 PbF2, 1.5 YF3, and 2.5 EuF3, in mol %) have been analyzed and compared. The Eu3+ ions in the glass ceramics are incorporated into a crystalline environment with higher symmetry and lower energy co…
Results of united atom molecular dynamics simulations of a n-C120H242 melt at 450 K are presented. It is shown that the results of mean square displacement, dynamic structure factor, end-to-end vector autocorrelation, and shear relaxation modulus can consistently be described by the Rouse model with a single set of fi…
Poly( p -phenyleneethynylene)- and heteroaromatic-containing poly(phenylene)-based conjugated polymers having photoisomerizable azobenzene units in the main chain were prepared using palladium-catalyzed cross-coupling reaction of 4,4‘-diiodoazobenzenes with 1,4-diethynylbenzenes and bis(trimethylstannyl)heteroaromatic…
Linear thermal expansion and magnetostriction measurements under a magnetic field up to 20 kOe, applied parallel and perpendicular to the measuring direction and in the temperature range of 10–300 K, have been performed on a Ni2MnGa polycrystal. The effects of zero-field cooling and field cooling on both the self-stra…
This paper briefly reviews some recent work demonstrating the partial breakdown of the colloidal fluid ↔ atomic fluid analogy. The success of liquid state theory for atomic fluids stems in part from the van der Waals picture, where steric interactions dominate the structure, and attractive interactions can be added as…
New highly-ordered compositions of nanopolyacetylene (NPA) were recently synthesized. These compositions are highly stable and could be prepared in the form of solutions, films or fibers. Raman scattering in NPA exhibits high intensity of Stokes and anti-Stokes lines; long sequence of overtones and combination bands;…
We have investigated the anisotropic decomposition of polyimide molecules induced by irradiation of linearly polarized ultraviolet light (LPUVL). Three polyimides were examined: poly [4,4′-oxydiphenylene-pyromellitimide], poly [4,4′-oxydiphenylene-1,2,3,4-butanetetracarboximide] and poly [4,4′-oxydiphenylene-1,2,3,4-c…
We demonstrate that neutron diffraction measurements make it possible to quantity elastic strains within the interior of solid samples, and thus have great potential for addressing a wide range of problems connected with the characterization of the mechanical properties of geological materials. We use the time‐of‐flig…
The hydrodynamic forces between Brownian spheres are determined from a measurement of the correlated thermal fluctuations in particle position using a new method: two–particle cross–correlation spectroscopy. A pair of 1.3 µm diameter polymer–coated poly(methylmethacrylate) particles were held at separations of between…
Simulation calculations are reported for single-chain polymer–wall conformation-averaged potentials of mean force and segment-density profiles for homopolymers of different structures as a function of the segment–wall attractive potential. When there is no attraction between the wall and the polymer segments, the pres…
Nanocomposite SmCo5+x wt %α-Fe (x=0, 20, 30, and 35) powders were prepared by mechanical milling and subsequent annealing. X-ray analyses show that hard phases can be 1:7, 1:5, or 2:7 phase with the increase of α-Fe content in as-milled powders annealed at 550 °C for 30 min. The high remanence and maximum energy produ…
BACKGROUND: Because saphenous vein grafts (SVGs) exhibit greater cellular heterogeneity and worse clinical outcomes than arterial grafts (AGs), we examined oxidative stress and lipid retention in different vascular conduits. METHODS AND RESULTS: In a porcine model of graft interposition into carotid artery, superoxide…
A dramatic increase of the clearing temperatures of liquid crystals based on bis(cyclohexyl)ethane 1 by 50 to 70 K can be achieved by the perfluorination of the central ethylene link. Conformational analysis indicates that this effect is due to the increased rigidity of the mesogenic core structure and to the suppress…
A highly efficient algorithm for the reconstruction of microstructures of heterogeneous media from spatial correlation functions is presented. Since many experimental techniques yield two-point correlation functions, the restoration of heterogeneous structures, such as composites, porous materials, microemulsions, cer…
The strontium bismuth tantalate vanadate, SrBi2Ta1.8V0.2O9, (SBTV) layered perovskite ferroelectrics were made by solid state powder sintering. It was found that the SBTV ferroelectrics had the same crystal structure as that of strontium bismuth tantalate, SrBi2Ta2O9 (SBT), but an increased paraferroelectric transitio…
Transparent optical nonlinear crystallized glasses with the composition of 25La2O3 25B2O3 50GeO2, stoichiometric to ferroelectric stillwellite-type LaBGeO5 crystalline phase, have been prepared by a two-step heat-treatment (first heat treatment: T1=670 °C, t1=10 h, second heat-treatment: T2, t2), and their second harm…
In this paper we present fundamental studies elucidating the role of entropy in particle suspensions. We focus on systems composed of large colloidal particles along with a second, usually smaller species such as a particle or polymer. We describe direct measurements of these interactions in suspension, and we systema…
In this article, the Jiles–Atherton model is modified to elucidate the variation of magnetic properties with grain size and dislocation density. The modified model predicts generally that coercive field increases with increasing dislocation density and inverse grain size and that remanent flux density and permeability…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSupramolecular Assembly of Amide DendronsChulhee Kim, Kyoung Taek Kim, Youngkyu Chang, Hyun Hoon Song, Tai-Yon Cho, and Hye-Jin JeonView Author Information Department of Polymer Science and Engineering Inha University, Inchon 402-751, Korea Department of Polymer Scienc…
Among various magnetic orderings exhibited by transition-metal compounds, ferromagnetism is the most important particularly in technological aspects. Recent intensive studies on the colossal magnetoresistance (CMR) have given even another reason for the importance of ferromagnetism. It would be very useful if one coul…