Materials Literature
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PVDF samples with high beta content (80%), prepolarized at room temperature, were heated to higher temperatures. The polarization was measured first under open circuit conditions at the high temperature and then after cooling down again to room temperature For elevated temperatures up to 175 degrees C the polarization…
The authors have succeeded to prepare dense sintered bodies of perovskite LaNiO3, which shows a metallic conduction, by HIPping without flux such as Na2CO3. The stoichiometric mixture of La2O3 and NiO was precalcined in air at 900°C for 5h. The ground sample was then sintered at 1100° or 1300°C in air for 20h. The sin…
A number of fulvene compounds, which can polarize to give rise to intramolecular charge transfer (ICT), have been synthesized, and the second-order molecular hyperpolarizability (β)and dipole moment (µg) have been calculated by using the MOPAC program. The macroscopic non-linearity (second-harmonic generation; SHG) ev…
A new theory predicting the biaxial tensile properties of a triaxial-weave fabric is presented. This theory is based on the plain-weave theory developed by Kawabata, Niwa, and Kawai in 1973 and improved by Kawabata in 1984. The basic structures of the fabric are (i) the thread-spacing of two warp threads and one weft…
The dinuclear metal complex Na[Cr2(L-tart2H)(phen)2] forms a lyotropic liquid crystalline phase with water, even in dilute solution, and the mesophase is proposed to have a chiral lamellar structure consisting of monolayers of molecules, which are formed by extensive stackings between the phen groups and separated by…
New photochromic spiropyrans existing in a stable coloured form are prepared from merocyanine dyes by irradiation with visible light.
Abstract The environmental stress‐cracking behavior of poly(ethylene terephthalate), PET, has been studied by exposing PET sheet samples to a stress‐cracking liquid, at constant stress, for various periods of time. Samples evaluated are of equivalent molecular weights but vary in copolymer concentrations. The characte…
Dielectric properties of a polymer-dispersed liquid crystal (PDLC) film comprising of liquid crystal, octyl cyanobiphenyl (K-24) and polymethyl methacrylate (PMMA) are reported as a function of frequency (100 Hz-1.0 MHz) in the temperature range of 25°C to 45°C. A dielectric dispersion in the low frequency region (∼1…
As part of research on corrosion phenomena in the oxygenfree high conductivity (OFHC) copper pipes of the stator cooling circuit of a power plant turboalternator and the possibility of using copper inhibitors, some prefilming systems have been investigated, taking the common treatments with benzotriazole as a starting…
Abstract The miscibility behaviours of thermoplastic polyurethane elastomers (TPUs) with chlorine‐containing polymers were studied. Four kinds of TPUs containing 20, 40, 60 and 80wt% of poly(caprolactone) (PCL) diol as a soft segment were used for blending. Poly(vinylidene chloride‐co‐vinyl chloride) (P(VDC‐VC)) with…
Discusses the AC dielectric breakdown of alumina, aluminium nitride and cordierite glass ceramics (MgO-Al/sub 2/O/sub 3/-SiO/sub 2/) at room temperature. The importance of specimen shape, thickness, surface finish and test conditions are assessed. For dielectric breakdown tests specimens were prepared in the form of 2…
Many factors influence the preparation and quality of graphite targets for 14 C accelerator mass spectrometry (AMS). We identified four factors (sample size, H 2 pressure, catalyst temperature and pretreatment time) as potentially critical, and investigated their effects on two particular characteristics: the integrat…
Inductively coupled argon plasma spectroscopic analysis was used to quantify titanium, aluminum, and vanadium corrosion products released by superficial layers of identically shaped commercially pure titanium and Ti-6A1-4V alloy dental implants. Halves of each of two originally sterile groups were analyzed directly fr…
The principal mission of the Penetration Mechanics Branch (PMB) of the Terminal Ballistics Division (TBD) of the Ballistic Research Laboratory (BRL). Aberdeen Proving Ground, MD, is research and development leading to improvements in the terminal ballistic performance of kinetic energy (KE) long rod penetrators. This…
The addition of Cu greatly improve the hot workability of cast Pr(Nd)FeB magnets, which makes possible the production of aligned magnets by hot deformation of the cast structures. Substantial amounts of a liquid phase identified as the Pr (Nd)-rich phase are extruded from these materials during hot deformation. Howeve…
Cobalt ferrite has the so-called inverse spinel structure, with one-half of Fe3+ions on A sites and the rest, together with Co2+ions, on B sites at room temperature. The cation distribution of the cobalt ferrite, however, has been reported to change through heat treatments. During the head-treatment, magnetic and elec…
The di-µ-oxo technetium(VI) complexes [{TcN(S2CNEt2)}2(µ-O)2]1, [{TcN(S2CNC4H8)}2(µ-O)2]2, [AsPh4]2[{TcN(CN)2}2(µ-O)2]4 and [AsPh4]2[{TcN(edt)}2(µ-O)2]5(H2edt = ethane-1,2-dithiol) have been prepared either by reaction of [{TcN(OH2)3}2(µ-O)2]2+ or Cs2[TcNCl5] in Na4P2O7 solution with the appropriate ligand. The ESR sp…
Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.
Regular well-faceted crystals located on the inner side of homogeneous poly(p-phenylene) films with a relatively large degree of polymerisation have been prepared by electrochemical oxidation of benzene in concentrated H2SO4 without adding Lewis catalysts.
The tensile properties and deformed microstructures of zirconium in the annealed condition have been investigated in both the rolling (RD) and transverse (TD) directions at three strain rates of 10−4, 10−3 and 10−2 s−1 at different temperatures in the range 298–673 K in order to understand the extent of anisotropy in…