Materials Literature
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The phase transition from the isotropic (I) to nematic (N) liquid crystalline suspension of F-actin of average length ł> or =3 microm was studied by local measurements of optical birefringence and protein concentration. Both parameters were detected to be continuous in the transition region, suggesting that the I-N tr…
The effects of molecular architecture on the fracture properties of semicrystalline polymers were probed at diblock copolymer-reinforced interfaces between polystyrene (PS) and polyethylene (PE). The PE used for this study was a model ethylene−butene copolymer which was chosen for its compatibility with hydrogenated 1…
The segmental tris-tridentate ligand L7 reacts with stoichiometric quantities of Ln(III) (Ln=La-Lu) in acetonitrile to give the complexes [Ln(2)(L7)(3)](6+) and [Ln(3)(L7)(3)](9+). Formation constants point to negligible size-discriminating effects along the lanthanide series, but Scatchard plots suggest that the self…
A series of perovskites with the compositions NaTi x Nb 1 - x O 3 - 0.5 x (0 ≤ x ≤ 0.2) has been synthesized for the first time using the sol−gel method. Combined Rietveld analysis of powder neutron and X-ray diffraction data reveals that these phases adopt the structure of the end-member perovskite NaNbO 3 with the s…
A new family of three-dimensional cubic-like [M(dca)3]− networks (dca = dicyanamide) templated by appropriate cations has been constructed and structurally characterized by X-ray crystallography.
Well-defined arrays of porphyrins attached to a rigid polyisocyanide backbone have been synthesized and their physical and optical properties studied. The helical polymers are rigidified by an inter-side chain hydrogen-bonded network and have an average mass of 1.1 x 10(6) Daltons and a polydispersity index of 1.3. Ea…
The layer-by-layer deposition method to prepare multilayers of polyelectrolytes of alternating charge has been followed in situ by means of optical reflectometry. It has been shown previously that in solutions containing both weak polyelectrolytes and appropriate salt the buildup of multilayers is modified and becomes…
Some recent publications on ferromagnetic resonance in amorphous wires mention presumably new kind of anisotropy, called there circumferential anisotropy, as an explanation of various spectral features. In this paper we argue that there is no special reason to speak of the new kind of anisotropy, since the observed sp…
Using density-functional theory we assess the stability of bulk and surface oxides of the late 4d transition metals in a ``constrained equilibrium'' with a gas phase formed of O2 and CO. While the stability range of the most stable bulk oxide extends for ruthenium well into gas phase conditions representative of techn…
Ultrasonic attenuation and phase velocity measurements have been carried out in the ferromagnetic perovskites La_{2/3}Ca_{1/3}MnO_3 and La_{2/3}Sr_{1/3}MnO_3. Data show that the transition at the Curie temperature, T_C, changes from first- to second-order as Sr replaces Ca in the perovskite. The compound with first-or…
Mercaptoacetic acid-capped spherical silver nanoparticles with a diameter of about 17 nm were prepared by a simple chemical reaction. The formation process of the silver nanoparticles was investigated by UV−visible (UV−vis) spectroscopy and transmission electron microscopy. The results show that the spherical and rodl…
Based on a detailed modeling of the Fermi surface topology of MgB2 we calculated the anisotropy of the upper critical field Bc2 within the two gap model. The sigma-band is modeled as a distorted cylinder and the pi-band as a half-torus, with parameters determined from bandstructure calculations. Our results show that…
Unified geometric approach to describing kinematics of elastic and plastic deformations of continuous media is suggested. On the base of this approach we study mechanical deformations, viscous flow, and heat transport in glassy plastic media. As a result we derive appropriate differential equations for these phenomena…
Neutron diffraction experiments were carried out on aqueous solutions containing either guanidinium or thiocyanate ions. The first-order difference method of neutron diffraction and isotopic substitution was applied, and the hydration structures of two of nature's strongest denaturant ions were determined. Each ion is…
Surface-enhanced Raman scattering (SERS) of adsorbed molecules on gold nanorods (NRs) with dimensions of 10 nm × 27 nm was studied on silica surface with low to high surface coverage of NRs. The study was carried out to investigate both the dependence of the SERS intensity on the number of NRs and the NRs spacing on t…
We present a simple analytical model for the forces that determine jet diameter during electrospinning as a function of surface tension, flow rate, and electric current in the jet. The model predicts the existence of a terminal jet diameter, beyond which further thinning of the jet due to growth of the whipping instab…
In this paper we present the results of a study of the effect of high-temperature stress annealing in nitrogen on the index of refraction of SiO<sub>2</sub> layers in MOS (metal/oxide/semiconductor) devices. The dependence of mechanical stress in the Si-SiO<sub>2</sub> system on the annealing conditions has been exper…
A novel approach to the teaching of material to engineering students is outlined. It starts from the overview of the "world" of materials made possible by material property charts, and develops both an understanding of material properties and skills in selecting materials and processes to meet design specifications. I…
In this paper tuneable optical filters based on liquid crystal Fabry-Perot interferometers (LCFPI) are presented. Liquid crystal (LC) devices are lightweight and suitable for compact arrays with a large number of pixels, as shown in high resolution flat panel displays. The fabricated filters offer a high finesse (119)…
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