Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
We present Molecular Dynamics (MD), Quasi Harmonic Lattice Dynamics (QHLD) and Energy Minimization (EM) calculations for the crystal structure of Ne, Ar, Kr and Xe as a function of pressure and temperature. New Lennard-Jones (LJ) parameters are obtained for Ne, Kr and Xe to reproduce the experimental pressure dependen…
Abstract Fiberglass piping has typically been prohibited from use in dry deluge fire protection systems and in confined spaces for reasons of flammability, smoke density and toxicity. Advanced resin technology has emerged which breaks through these barriers. The .light weight, corrosion resistance and low maintenance…
The -type cubic compound, , undergoes below a spontaneous magnetic transition at . The magnetic phase diagrams have been determined from the magnetization curves measured on a single crystal in fields up to 10 T. The corresponding magnetic structures have been determined from neutron diffraction studies on the same cr…
Als ferromagnetisch gekoppeltes Spinpentamer wurde das makrocyclische Polyradikal 1 konzipiert. Für diesen Kohlenwasserstoff ergaben Magnetisierungsmessungen einen durchschnittlichen Spin von S = 10 im Grundzustand, was der bislang größten für ein organisches Molekül gemessenen Spinquantenzahl entspricht. Ar = tBuC6H4.
The title compound is not a hexaboride, as was believed for many years. It is therefore not surprising that its structure also contains a novelty: for the first time a pentagonal B7 bipyramid (shown on the right) has been identified as part of the framework of boron atoms in a solid-state compound.
The temperature dependence of the Debye-Waller factors of a 9.4 mol% stabilized cubic ceramic was studied in the range 4-1923 K using neutron powder diffraction. It was found that the data could not be modelled on a harmonic Debye-like model with an additive static disorder component but are significantly anharmonic.…
The porphyrin–surfactant interaction determines the activity of the title catalysts. Amphiphilic porphyrin derivatives (e.g. 1 with M=MnCl, R=CH2CH2(OCH2CH2)2OH) are easy to prepare and can be included in micellar phases.
We study statistical properties of energy spectra of two-dimensional quasiperiodic tight-binding models. Taking into account the symmetries of models defined on various finite approximants of quasiperiodic tilings, we find that the underlying universal level-spacing distribution is given by the Gaussian orthogonal ran…
Resistivity (15 - 710 K), magnetization (80 - 723 K), and calorimetric (200 - 623 K) measurements on have shown evidence for the formation of Jahn - Teller (JT) polarons below . Above 560 K, activated conduction with is observed and shows Curie - Weiss behaviour. Over the temperature range 270 - 340 K, the conductivit…
Model compounds for silica surfaces modified with metal complexes are provided by the mononuclear anionic diperoxo species 1 and the dinuclear complex anions 2 (M = Mo, W). They were obtained in fair to nearly quantitative yields by the reactions of Ph3SiOH and [Ph2Si(OH)]2O, respectively, with an aqueous solution of…
We report an ellipsometry study of the wetting of hexane on water. By adding salt to the water, we are able to tune the Hamaker constant of this system. This allows us to demonstrate, for the first time, that two rather than one wetting transitions can exist in a single system. Upon increasing the temperature, a disco…
The cold-cathode electron emission properties of amorphous tetrahedral diamondlike carbon are promising for flat-panel display and vacuum microelectronics technologies. The onset of electron emission is, typically, preceded by “conditioning” where the material is stressed by an applied electric field. To simulate cond…
Nonscattering glasses that are indefinitely stable with respect to crystallization can be prepared from the title compounds. In these solid solutions, the dendritic substituents effectively suppress interactions between the phthalocyanine units (see the structure depicted on the right).
The ruffle of the porphyrin increases with the number of meso substituents. (Octaethylporphyrin)nickel(II) undergoes nucleophilic substitution reactions upon treatment with alkylating reagents such as butyllithium, hydrolysis with water, and oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone [DDQ; Eq. (a)]. Alky…
We report a principle that allows one to write visible light emitting silicon patterns of arbitrary shape down to the submicrometer scale. We demonstrate that porous Si growth can electrochemically be initiated preferentially at surface defects created in an $n$-type Si substrate by ${\mathrm{Si}}^{++}$ focused ion be…
Silver nanocrystals have been grown on Xe buffer layers at 50 K. These 3D nanocrystals are delivered to $\mathrm{Si}(111)\ensuremath{-}(7\ifmmode\times\else\texttimes\fi{}7)$ surfaces when the Xe layer is desorbed, but the density observed on the surface depends strongly on the buffer layer thickness. This dependence…
A new coordination mode for the porphyrin ligand is found in [B2O2(BCl3)2(tpClpp)] (tpClpp=dianion of 5,10,15,20-tetra-p-chlorophenylporphyrin; the p-chlorophenyl groups are omitted for clarity in the picture shown on the right). This complex contains a four-membered B2O2 ring in the cavity of the ligand. The two boro…
Der bislang größte anorganische Cluster [(MoO3)176(H2O)80H32](2±2)− 1 (im Bild rechts sind die Mo-O-Polyeder gezeigt), der jetzt röntgenstrukturanalytisch charakterisiert wurde, weist neben einem Hohlraum mit einem Durchmesser von 2.3 nm bemerkenswerterweise die Stöchiometrie eines reduzierten, protonierten und hydrat…
Simply mixing solutions of the title compound 1 and tetrathiafulvene (TTF) in acetonitrile provides the charge-transfer complex 2. Here, 1 functions as a novel electron acceptor and is present in the complex as a radical anion. An electrical conductivity of up to 3 S cm−1 was determined for 2 with a two-point powder m…
We have investigated the formation of polymer walls for high polymer content liquid crystal (LC) formulations, using a patterned electric field to induce phase separation. The effect of this field on the phase separation temperature of a LC/monomer mixture is studied as a function of the photopolymerizable monomer con…