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Scherinduzierte rheologische Anisotropie von verschiedenen Polyethylen-Schmelzen / Shear induced Anisotropy of various Polyethylene Melts

Acid–Base Reactions of Transition Metal Oxides in the Solid State

Subsolidus compatibility data exist for a number of ternary oxide systems containing a transition metal oxide. Ternary diagrams, suitable for the present purpose, are limited mainly to those that include FeO, Fe 2 O 3 , ZnO, or Cr 2 O 3 , and these are examined in the context of Lewis acid–base interaction by consider…

Preparation and Electrical Properties of Conducting Polyaniline-Polycarbonate Composite Films

Conducting polymer polyaniline and insulating polymer polycarbonate composites have been prepared. Electrical conductivity can be controlled in a wide range (more than 15 orders of magnitude) by a small amount of polyaniline. This characteristic can be explained by a percolation model. That is, at the threshold concen…

Modified Polyanilines via Electrochemical Copolymerization of Aniline and para‐phenylenediamine Derivatives

Copolymerization of 2,5‐diaminobenzenesulfonic acid (DABSA) and para ‐phenylenediamine (PPDA), respectively, with aniline (AN) was electrochemically performed by cyclic voltammetry on ‐coated electrodes in 1 M HCl. The copolymerization rate strongly depends on the amount of DABSA/PPDA in the comonomer feed. The compos…

A new approach to porphobilinogen and its analogs

The van Leusen pyrrole synthesis was used to assemble three potential precursors of porphobilinogen, one of which was converted to the natural product using a new method for the direct alkylation of β-hydroxymethylpyrroles.

Morphology Development through an Interfacial Reaction in Ternary Immiscible Polymer Blends

We studied the morphology development of ternary immiscible blends through an interfacial reaction between components. This phenomenon was observed in two ternary blend systems; one is composed of polyamide(6) (PA6), polycarbonate (PC), and poly[styrene- b -(ethylene- co -butylene)- b -styrene] (SEBS), and the other i…

Cu12Sb4S13: A Temperature-Dependent Structure Investigation

Synthetic tetrahedrite, Cu 12 Sb 4 S 13 , obtained by reaction of the elements, has been investigated at various temperatures in the 295–573 K range. It crystallizes in the cubic system with a = 10.3293 (6) Å, V = 1102.1 (2) Å 3 , space group I \overline 43 m and Z = 2 at room temperature. The structure refinement con…

A Superelastic Shape-Memory-Alloy Beam Model

The present paper proposes a simple shape-memory-alloy beam model, based on the classical Euler-Bernoulli beam theory. Due to restrictive kinematical assumptions, a one-dimensional constitutive equation is used. Thus, the material behavior is described through a simple l-D phenomenological model, which allows for diff…

Blue Light Emitting Nanosized TiO2 Colloids

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTBlue Light Emitting Nanosized TiO2 ColloidsYanjing Liu and Richard. O. ClausView Author Information Fiber & Electro-Optics Research Center Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University Blacksburg, Virginia 24061-0356 C…

Electrochemistry of Poly(2,2′‐dithiodianiline): A New Class of High Energy Conducting Polymer Interconnected with S‒S Bonds

2,2'‐Dithiodianiline (DTDA), a conducting polymer having a disulfide bond in it, has been proposed as a new class of high energy storage material. DTDA has one S‒S bond interconnected between two moieties of anilines. DTDA was electrochemically polymerized to form an electroactive thin film. The structure of the poly(…

Variable structure control of shape memory alloy actuators

A shape memory alloy (SMA) actuator consisting of a number of thin NiTi fibers woven in a counter rotating helical pattern around supporting disks is first described. This structure accomplishes a highly efficient transformation between force and displacement overcoming the main mechanical drawback of shape memory all…

Neutron Diffraction and Computational Study of Zeolite NaX: Influence of SIII‘ Cations on Its Complex with Benzene

The crystal structure of zeolite NaX (Si:Al = 1.2) and that of its complex with benzene have been determined at 5 K by Rietveld analysis of powder neutron diffraction data in space group Fd 3. For NaX, a = 25.0328(5) Å, R wp = 4.25%, and R p = 3.27%. For NaX + benzene, a = 25.0496(7) Å, R wp = 4.60%, and R p = 3.52%.…

Orthorhombic phase of crystalline polyethylene: A Monte Carlo study

In this paper we present a classical Monte Carlo simulation of the orthorhombic phase of crystalline polyethylene, using an explicit atom force field with unconstrained bond lengths and angles and periodic boundary conditions. We used a recently developed algorithm which apart from standard Metropolis local moves empl…

Chromic Mechanism in Amorphous WO 3 Films

We propose a new model for the chromic mechanism in amorphous tungsten oxide films ( WO 3 − y ⋅ n H 2 O ) . This model not only explains a variety of seemingly conflicting experimental results reported in the literature that cannot be explained by existing models, it also has practical implications with respect to imp…

Antireflection behavior of silicon subwavelength periodic structures for visible light

We describe subwavelength surfaces etched into silicon wafers that exhibit antireflection characteristics for visible light. The wafers are fabricated by holographically recording a crossed-grating in a photoresist mask followed by reactive-ion etching to transfer the primary mask onto the silicon substrate. The depen…

Phase diagram of hard spheres confined between two parallel plates

A hard sphere system confined between two parallel hard plates is investigated theoretically. Using extensive Monte Carlo computer simulations, the phase diagram is calculated for the whole range of densities and plate separations ranging from one to two particle diameters. There occurs a strong first-order fluid free…

1. Ultrathin Multilayer Polyelectrolyte Films on Gold: Construction and Thickness Determination

Thin organic films fabricated by the successive deposition of the polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(styrenesulfonate) (PSS) have been successfully grown up to 24 layers on gold surfaces. These films are formed via electrostatic attraction between adjacent layers of opposite charge. Their c…

Macromolecular Cryocrystallography

The current techniques for X-ray-diffraction data collection from macromolecular crystals at cryogenic temperatures are reviewed. The development of the experimental methods is outlined and the basic concepts pertaining to radiation damage and cryoprotection are summarized. Emphasis is placed on the practical aspects…

Structure and magnetic order in undoped lanthanum manganite

The undoped lanthanum manganite system of nominal composition ${\mathrm{LaMnO}}_{3}$ has been analyzed by neutron powder diffraction for different sample heat treatment methods. Four distinct crystallographic phases have been identified: (i) an orthorhombic phase of space group Pnma and lattice parameters (at 300 K) a…