Materials Literature
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In water-based lyotropic liquid crystals (LCs), e.g., aqueous suspensions of V2O5, the electrooptical effects typical of thermotropic mesophases are difficult to observe, owing to the large conductivity and electrochemical reactions of the suspensions. Overcoming these difficulties, the authors demonstrate that V2O5 a…
Semi-flexible copolyimides with various alkyl chain lengths (BTDA-ODA/CnMPD PIs) were newly synthesized in N-methyl-2-pyrrolidone from benzophenonetetracarboxylic dianhydride, 4,4′-oxydiphenylene diamine, and 3,5-diaminobenzoyl n-alkanoates. The films were rubbed with varying rubbing densities, and on the rubbed surfa…
Atomistic simulation techniques are used to investigate the effect of proton-containing defects on the structure and stabilities of a range of grain boundaries of forsterite. We study two series of stepped {010} tilt boundaries that are at 90° to each other: one with the {100} plane as step wall and the other with the…
A new method for drilling holes in engineering ceramics by using a rotary ultrasonic tool has been developed. In this method, a drilling tool impregnated with abrasive particles is simultaneously rotated and vibrated. The mechanism of ultrasonic drilling is analysed using the concept of fracture mechanics and a new th…
Abstract Akzo Nobel Chemicals has recently introduced on the market an aromatic oligomeric phosphate (BDP) based on Bisphenol A. This product shows higher thermal and hydrolytic stability than other aryl phosphates. It provides similar or better fire retardant performance than an oligomeric phosphate (RDP) based on re…
We describe improvements to a previously reported hyper-Rayleigh scattering technique [J. Opt. Soc. Am. B15, 289 (1998) ], for measuring all rotational invariants of the first hyperpolarizability tensor. The full hyper-Rayleigh scattering tensor is expressed in terms of its rotationally invariant components leading to…
The ${\mathrm{La}}_{2\ensuremath{-}2x}{\mathrm{Ca}}_{1+2x}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ $(0.6<~x<~1.0)$ series has been successfully synthesized using a citrate gel technique in order to study their structure and properties as a function of x in the ${\mathrm{Mn}}^{4+}$-rich region of the phase diagram. Rie…
An approach for scaling the ac conductivity in ion-conducting glasses was recently demonstrated. Here we demonstrate that this proposed scaling can be applied to the corresponding ac permittivity and thus leads to a complete description of the scaling of both the real and imaginary components of the dielectric respons…
Porous silicon thin films created under laser illumination in fluoride solutions without biasing have been studied by a variety of techniques to investigate the film structure and photoluminescence (PL). The use of ultrathin silicon wafers allows us to perform plan view transmission electron microscopy studies without…
A relation between B -site transition metal and ferroelectricity is investigated in A B O 3 perovskite-type oxides. We focus on intensity of the covalent bonds between the B-site atom and the oxygen octahedron and evaluate Harrison's covalency parameter α. The density functional theory within the local density approxi…
In this paper we discuss the formation and shape of the meniscus between a free-standing film of a smectic-A phase and a wall (in practice the frame that supports the film). The wall may be flat or circular, and the system with or without a reservoir of particles. The formation of the meniscus is always an irreversibl…
The incorporation of Fe 2+ was investigated in four natural cordierite samples. 57 Fe Mössbauer, single-crystal UV-VIS optical absorption, and X-ray absorption spectroscopies, as well as X-ray single-crystal diffraction were used. Mössbauer, optical, and XAS spectroscopy show that Fe 2+ is incorporated on two differen…
A model of contact damage accumulation from cyclic loading with spheres and ensuing strength degradation in relatively tough, heterogeneous ceramics is developed. The damage takes the form of a quasi‐plastic zone beneath the contact, consisting of an array of closed frictional shear faults with attendant “wing” microc…
An easy-to-apply analytical (“mathematical”) stress model is developed for the prediction of the stresses in, and the bow of, a circular substrate/thin-film structure subjected to a change in temperature. The model can be helpful for stress–strain analyses and physical design of thin film systems fabricated on circula…
Abstract Physical blowing agents such as n‐pentane and methyl formate and, for comparison, chemical blowing agents such as water were used to prepare structural polyurethane rigid foams of different densities by reaction injection molding. Experimental runs were carried out with formulations based on oligomeric isocya…
The fuel elements for Chinese 10 MW High Temperature Gas-cooled Reactor (HTR-10) are spherical all- ceramic fuel elements (SFE). TRISO (Tri-isotropic) coated fuel particles (CP) are uniformly dispersed in the graphite matrix of the fuel element. All radiological fission products are almost completely retained inside t…
An integrated computational approach to microstructural evolution and electrical transport in ceramic gas sensors has been proposed. First, the particle‐flow model and the continuum‐phase‐field method are used to describe the microstructural development during the sintering of a prototype two‐dimensional film. Then, t…
This paper presents a feasibility study to develop conductive knitted-fabric-reinforced thermoplastic composites for electromagnetic shielding applications. Polypropylene is the matrix phase, and glass fibers are the reinforcement phase of the composite material. Stainless steel wires and staple yarns are incorporated…
The effect of postdeposition annealing to 600 °C in vacuum on the hardness, modulus, film stress, and sp3 content of nonhydrogenated amorphous carbon was studied. The films were deposited using a filtered cathodic arc source and the film properties were varied by controlling the substrate bias. In films with an initia…
Abstract The grafting of polystyrene onto dissolved starch in a twin screw extruder has been studied. This copolymerization was initiated using the thermal initiators benzoyl peroxide and K 2 S 2 O 8 . As end product a mixture containing polystyrene‐grafted starch, homopolymer of polystyrene and starch was obtained. P…