Materials Literature
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Great caution must be exercised when applying the 1 CF2≈1.5 CH2 “rule” for surfactants: when grafted to a fluorinated chain, a hydrocarbon chain does not fully participate in micellization and adsorption processes, so these are controlled primarily by the length of the -CF2- chain. It is proposed that the hydrocarbon…
No heteroatom required! In many solid-phase syntheses, after the release from the polymer support a heteroatom (e.g. O, S, N) remains in the substrate as a residue of a linking protecting group. With polymer-bound tin reagents cleavage and cyclization of the substrate with C-C bond formation (see picture) can now be a…
The stability of the oxidation state +4 decreases from silicon to element 114, as shown by relativistic and nonrelativistic calculations on the hydrides, fluorides, and chlorides of the Group 14 elements (the energies of the decomposition reaction (1) are given in the plot). Thus it is unlikely that superheavy element…
A superconducting point contact is used to determine the spin polarization at the Fermi energy of several metals. Because the process of supercurrent conversion at a superconductor-metal interface (Andreev reflection) is limited by the minority spin population near the Fermi surface, the differential conductance of th…
Naked metallic and semiconducting single-walled carbon nanotubes (SWNTs) were dissolved in organic solutions by derivatization with thionychloride and octadecylamine. Both ionic (charge transfer) and covalent solution-phase chemistry with concomitant modulation of the SWNT band structure were demonstrated. Solution-ph…
The grain size dependencies of magnetic properties in granular perovskite La 0.82 Sr 0.18 MnO 3 have been investigated. With grain growth, both an evident decrease of magnetization and the lattice distortions have been simultaneously observed. The phenomenon suggests a structure-coupled change of magnetism in the hole…
The acetonitrile effects on the quenching and photosensitized charge separation using two partially quaternized poly(1-vinylimidazole)-bound ruthenium(II) complexes, RuQPIm-19 and RuQPIm-44, wherein the numbers represent the degree of quaternization in molar percentage, have been investigated. The systems consist of R…
A method is described to estimate the heat generation rate of various high-level waste (HLW) forms composed primarily of either a sludge (with a composition similar to that in the Hanford HLW tanks) or borosilicate glass. The main heat source is from radioactive decay and subsequent self-absorption of particles emitte…
In order to improve the margin for operating temperature changes and to achieve high recording performance, Co–Sn substituted Ba-ferrite particles were investigated. It was found that BaFe12—2xCoxSnxO19 particles with x = 1.10 to 1.40 not only have a coercivity suitable for magnetic recording, but also have a very low…
Vesuvianite is a common rock-forming silicate mineral with the general chemical formula X19Y13Z18T0.5O68W10 , where X = Ca, Na, Ln, Pb, Sb; Y= Al, Mg, Fe, Ti, Mn, Cu, Zn; Z = Si; T= B; W= (O, OH, F). Vesuvianite is ideally tetragonal with space group P4/nnc, but many samples show physical properties that indicate devi…
Precursors possessing Ti–N bonds were prepared by the reactions between Ti(NMe2)4 and each of three diamines H2NCH2CH2NH2, Me(H)NCH2CH2N(H)Me, HN(CH2CH2)2NH (Ti(NMe2)4:diamine = 1:2), and were converted into ceramics by pyrolysis. The reactions with H2NCH2CH2NH2 and HN(CH2CH2)2NH led to the formation of insoluble soli…
We present refined diffuse neutron scattering measurements performed in the long-range-ordered phase of potassium thiocyanate $(T<{T}_{c}).$ The analysis of the data yields that the diffuse scattering is due to the presence of order-parameter fluctuations that appear as a precursor to the order-disorder phase trans…
The search of the off-centre displacement of an impourity iron from the crystal lattice site in the ground electronic state has been performed by the ionic thermocurrent (ITC) method for Ga+, Ge2+ v− c, and Sn2+ v− c centres in some alkali halides. No ITC peak has been found at T>5 K for Ga+ ions. One ITC peak at the…
Cracking, or disbonding, along the fusion boundary in dissimilar metal welds has been a persistent problem, particularly in applications where austenitic alloys are clad on to structural steels for corrosion protection. Many failures in dissimilar metal welds occur as a result of cracking along a boundary that runs pa…
Different plant analysis methods including varied incubation times with 0.5N and IN hydrochloric acid (HCl), diacid [nitric (HNO3) and perchloric (HClO4) acids], triacid [HNO3, sulfuric acid (H2SO4) and HClO4], H2SO4+hydrogen peroxide (H2O2) (Wolf method), and 0.5N and lN ammonium acetate (NH4OAc) were evaluated for m…
A chain-adapted symmetry-mode analysis is presented for the symmetry change R 3 m > C12/c1 in ferroelastic lead phosphate. The primary and the secondary modes are derived for all relevant Wyckoff positions. The splitting schemes of the orbits and the patterns of the displacive modes are compatible with experimental di…
Nanocrystalline La 0.5 Na 0.5 TiO 3 powders were prepared by the stearic acid-gel method, and the grain sizes could be controlled by varying annealing temperatures. The sizes were determined to be from 14 to 50 nm using Scherrer's formula. A very strong blue-light emission band around 480 nm was clearly observed in th…
Instead of studying the cholesteric-smectic A transition from the analogy with superconductors, we present a direct investigation of the properties of this transition. The transition is of first order and a very simple relationship between the four basic lengths (correlation length, penetration length, layer spacing o…
A carbon tetrafluoride plasma discharge using a grafting mechanism and very short treatment times (a few milliseconds to a few seconds) was used to obtain high-quality reproducible surfaces that permit the homeotropic alignment of lyotropic as well as thermotropic liquid crystals. The intermolecular interactions betwe…
Two mechanisms of optical response in liquid crystals (LC) of homologous series 4-n-butyl-4′-n-alkoxyazobenzenes (BAAB), namely the photochemical phase transition and reorientation in bulk of LC are considered. The temporal parameters of writing (Ar+ laser) and erasing (He-Ne laser) of information on BAAB on the basis…