Materials Literature
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The EtOH extract of the leaves of Holarrhena curtisii yielded five new steroidal alkaloids: 17-epi-holacurtine (3), 17-epi-N-demethylholacurtine (4), holacurtinol (5), 3alpha-amino-14beta-hydroxypregnan-20-one (7), and 15alpha-hydroxyholamine (8), in addition to the known compounds, holacurtine (1), N-demethylholacurt…
1200 Moleküle des Lösungsmittels können von einem Molekül des kationischen, dimeren Tensids 1 bei der Gelbildung in CHCl3 immobilisiert werden. Diese neuen Geliermittel enthalten chirale Gegenionen und bilden sowohl in organischen Lösungsmitteln als auch in Wasser Gele, indem sie sich zu helicalen Aggregaten zusammenl…
The selective incorporation of gold, when and where desired, within dendritic and multidendritic macromolecules can be accomplished by means of complexation on internal PNPNPS, PNPS, and PR2 groups; up to 90 AuCl moieties can be grafted into the internal layers of a multidendritic giant molecule (see picture).
Through a hole in a poly(ethyl acrylate) (PEA) layer that is electrochemically grafted to the surface of a vitreous carbon electrode-that is the route that must be taken by a growing polypyrrole nanowire in the electropolymerization of pyrrole. Chain growth is controlled by diffusion of the monomer through the DMF-swo…
A 1,3,5-alternate conformation of the pyrrole rings is adopted by the calix[6]pyrrole 1 in the crystal (see picture). Compound 1 was synthesized in a two-step process and although it crystallizes in the form of the adduct 1⋅3CH3COCH3⋅H2O⋅CHCl3, there are no solvent molecules in the cavity (cross section ca. 60Å2) of t…
The structural transformations and the photochromic properties of the 7-hydroxyflavylium ion have been investigated by means of the pH jump technique and continuous and pulsed light excitation. The various forms of flavylium compounds, trans- and cis-chalcone (Ct and Cc), quinoidal base A, and hemiacetal form B, are r…
The kinetics of the weight loss for the thermal decomposition of five different types of waste wood (forest wood, wood from demolition of buildings, dismantled slot machines, old furniture, and used or broken pallets) was investigated by dynamic and isothermal experiments in a thermogravimetric analysis (TGA) apparatu…
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…