Materials Literature
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Abstract Diels–Alder reaction between tribenzo[b,g,l]thiopheno[3,4-q]porphyrazine and dimethyl acetylenedicarboxylate at ca. 200 °C produced a substituted tribenzo[b,g,l]porphyrazine and 3:1 unsymmetrically substituted phthalocyanine, which were characterized by UV-VIS, MCD, NMR, and mass spectroscopies.
Results are presented of studies of the 154Sm1−x SrxMnO3 system using neutron powder diffraction and small-angle polarized neutron scattering. An analysis of the neutron diffraction spectra showed that at T < 180 K these exhibit typical Jahn-Teller distortions of the manganese-oxygen octahedrons which persist under fu…
A comparative study of the Hall effect and the longitudinal resistivity of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ $(x=0.30$ and $x=0.67)$ thin films has been performed. The underdoped samples $(x=0.30)$ show a semiconductor-to-quasimetal transition, and a colossal magnetoresistance (CMR)…
A hyperbranched aromatic polyamide has been prepared by direct polycondensation of 5-(4-aminobenzoylamino)isophthalic acid (ABZAIA), using the modified Higashi's method. The resultant polymer is soluble in aprotic polar solvents such as DMF, DMAc, NMP, and DMSO. Intrinsic viscosities of poly(ABZAIA) samples, measured…
In this article we present a low-cost, high-speed, high-accuracy in situ thin film measurement system for real-time process monitoring and industrial process control. This sensor, the two-channel spectroscopic reflectometer (2CSR), is a hybrid of spectroscopic ellipsometry and spectroscopic reflectometry. In 2CSR a po…
The optical and electrical properties of porous silicon microcavities are strongly dependent on the environment. For highly luminescent samples both the luminescence intensity and the peak position are affected by organic substances, which also strongly modify the electrical conductivity, giving the possibility to obt…
An earlier study demonstrated the presence of 11 morphologically distinct demes (‘morphotypes’) within the Diploneis smithii/D. fusca species complex in a single sample from Ganavan near Oban on Scotland's west coast. Two of these demes were subsequently shown to occur elsewhere around the British coastline and to kee…
Naphthalene containing aralkyl novolac epoxy resins were synthesized by the condensation of p-xylylene glycol with 2,7-dihydroxynaphthalene or 2-naphthol followed by the epoxidation of the resulting aralkyl novolacs with epichlorohydrin. The mechanical and dynamic viscoelastic properties of cured aralkyl novolac epoxy…
A substance for solidifying waste containing 129I is sought that effectively sorbs iodine to inhibit its release from repository into the environment. Three candidate media—commercial alumina cement mixed with calcium sulfate and/or calcium hydroxide—were investigated. The criterion applied for evaluating iodine sorpt…
The RNA-dependent RNA polymerase (P2) from bacteriophage Phi6 has been cloned and the protein overexpressed in Escherichia coli to produce an active enzyme. A fully substituted selenomethionyl version of the protein has also been produced. Crystals of both proteins have been grown; most belong to the monoclinic space…
Titanium oxide films with a thickness of a 400 nm were deposited on p-type Si(100) at room temperature by e-beam evaporation, and titanium dioxide was evaporated in oxygen environment at a pressure of 2×10−6–4×10−5 Torr. Effects of oxygen flow rate (FO2) on the properties of the films, such as surface roughness, compo…
We measure the azimuthal anchoring strength and easy axis gliding of the nematic 5CB on weakly anisotropic substrate. We study the anchoring evolution at a time scale ranging from a few minutes up to a few months. We separate approximately the elastic and the viscous response and we obtain the gliding velocity as a fu…
A new approach to the assembly and photochemical disassembly of molecular hosts is developed. It is based on photoinduced fragmentation in hydroxyalkyl dithianes and utilizes a novel spiro-bis-dithiane as a photolabile molecular tether to link two formylated macromolecular blocks, e.g., formyl calixarenes or formyl di…
The effect of aspartic acid, glutamic acid, hexaammonium tetrapolyphosphate, calcium phytate, and polyaspartic acid on calcium hydrogenphosphate dihydrate (CaHPO 4 ·2H 2 O, DCPD) crystal growth morphology was studied. The mechanism of additive−DCPD crystal interaction depends on the size and structure of the additive…
Abstract Surface treatments using glow discharge plasmas from O 2 and Ar were applied to blend sheets of poly(ϵ‐caprolactone)‐polycarbonate (PCL/PC), which had been produced by extrusion from melts of the mixture at various blend ratios. As to the reactivity of these two plasmas, O 2 ‐plasma forms the oxidative specie…
The chain dimensions 〈R2〉 of nondilute polymer solutions confined to a slit of the width D were studied using lattice simulations. It was found that the chain compression induced in good solvents by the concentration ϕ is enhanced in a slit relative to the bulk. The global dimensions of chains also change with ϕ in co…
The design of an optical element profile with specified transmission function for a given incident wave is of fundamental concern in optical design. A well-known example is the design of an aspherical surface in order to realize a spherical phase-only transmission. Various wave-optical system design methods lead to tr…
Syndiospecific silyloxy-functionalized polystyrene with high molecular weight was prepared using a (pentamethylcyclopentadienyl)titanatrane/MMAO catalyst system. The resulting polymer is soluble in polar organic solvents such as THF and shows good thermal stability. In addition, the compound Ni(acac)2 was used as a ca…
Yttrium calcium oxoborate (YCOB) and Nd:YCOB crystals of high optical quality and large dimension have been grown by the Czochralski method. Measurements of refractive indices have confirmed that these crystals were negative biaxial. The absorption spectra were determined and the various spectrum parameters were calcu…
Study of the Mössbauer effect over a range of both temperature and pressure on polycrystalline Fe-doped åkermanite, and X-ray measurements of spontaneous strain on single crystals of åkermanite under pressure, have been used to study the nature of the order parameters, and the characteristics for the transition of the…