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。
Low-dose, low-temperature kinematic and dynamical convergent-beam electron diffraction (CBED) patterns from thin organic crystalline films have been used for the measurement of structure-factor amplitudes and phases. Kinematic conditions are identified by the observation of uniform intensity within the CBED discs and…
Dreikernige Kupferkomplexe wurden mit einem in 2,4,6-Position modifizierten 1,3,5-Trihydroxybenzolliganden erhalten (siehe Bild; =Bipyridin, 2-Formylphenolat). Die m-Phenylenverbrückung führt in diesen Komplexen zu ferromagnetischen Wechselwirkungen durch Spinpolarisierung.
We have carried out DC magnetization measurements on spherical glassy carbon exposed to high temperatures and high pressures. The observed magnetic signals clearly depend on the sintering temperature. On the basis of the graphitization temperature (around 1400oC), the behaviour can be classified into three regions: (1…
Ein Triblockcopolymer als Templat und ein Organosiloxan oder ein organisches Additiv ermöglichten die erste Synthese von großporigen (bis zu 9.5 nm), dreidimensionalen, bikontinuierlichen mesoporösen SiO2-Materialien mit Ia3d-Symmetrie bei Raumtemperatur in wässrig-saurem Medium. Gezeigt ist eine Transmissionselektron…
Size-controlled nanocrystalline silicon (nc-Si) has been prepared from a-SiN x /a-Si:H/a-SiN x ('a' standing for amorphous) structures by thermal annealing. Transmission electron microscope analyses show that the lateral size of the nc-Si is controlled by the annealing conditions and the a-Si sublayer thickness. The d…
Einen nahezu kugelförmigen Cluster von etwa 2.5 nm Durchmesser bilden die Silberatome (blau), S2−-Liganden (gelb) und Phosphoratome der PnPr3-Liganden (grün) in [Ag188S94(PnPr3)30] (siehe Bild). Die Phosphanliganden stehen wie die Stacheln eines Igels vom Ag2S-Clusterkern nach außen ab, und das Schwefelteilgitter ist…
Cavities, indentations, and pockets aplenty! By means of self-activated silyl-assisted polyonio substitution (SASAPOS), meso-tetrakis(pentafluorophenyl)porphyrin can be nearly quantitatively converted into the twentyfold positively charged polycation 1, within which 20 counterions are housed. The most drastic steric a…
Polystyrene (PS) combs and dendrigrafts bearing di(hydroxymethyl) group termini at each branch end were used as starting materials for the preparation of branched and hyperbranched polymer structures with ferrocenyl moieties at their periphery. Quantitative acetalization of the 1,3-propanol ends using carboxaldehyde f…
Temperature-dependent magnetization and magnetoresistance of the Na doped La 1−x Ca x −y Na y MnO 3 type samples with x = 0.3 and 0 ≤ y ≤ 0.15, showing a rhombohedrally distorted perovskite structure with space group R c , have been studied under a pulsed magnetic field. With the increase in temperature from the low t…
Different solid/liquid "exchange" reactions involving divalent cations, protons, or ammonium ions have been performed at low/moderate temperatures (between 80 and 500 degrees C) on alpha-NaFeO2 dipped in molten salts (or acid) media. Several ferrites have been obtained which are nonstoichiometric with partially invers…
A lipid (1)-coated lipase can catalyze the oligomerization of diethoxydimethylsilane (DEDMS) in isooctane containing 2wt% water, where the polymerization occurs at the OH group of the coating lipid (1) in the enzyme cavity.
In an effort to understand the origins of the nearly constant loss in disordered materials, we report dielectric studies of a series of sodium germanate glasses, (Na2O)(x)(GeO2)(1-x) for x=0, 0.003, 0.01, 0.03, and 0.1 at temperatures between 85 and 700 K. Analysis of the conductivity scaling for these glasses demonst…
Single-walled carbon nanotubes (SWNTs) strongly adsorb macrocyclic tetraazaannulene complexes NiTMTAA and CuTMTAA from ethanol solutions, with a SWNT/complex mass ratio of ca. 5:4. According to the results of molecular mechanics modeling, this corresponds to dense monolayer coverage. A saddle-shaped conformation of th…
Amorphous hydrogenated carbon−germanium films (a-Ge X C Y:H) were fabricated by plasma chemical vapor deposition in an audio frequency (af) three-electrode reactor using tetramethylgermane (TMGe) as a source compound. Two types of the material, namely semiconducting (a-S) and insulating (a-I) films characterized by qu…
Diatoms are unicellular microalgae with intricate walls made from silica. In his Perspective, [Wetherbee][1] explains how these patterned walls are constructed. He highlights the report by [KrA¶ger][2] et al ., who show that key molecules in the silicification process, called silaffins, are highly phosphorylated in th…
Poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA) macromonomers were synthesized for preparation of a novel cytocompatible polymer. The cytocompatible polymer was composed of 2-methacryloyloxyethyl phosphorylcholine (MPC), n-butyl methacrylate (BMA), and the enantiomeric PLLA (or PDLA) macromonomer. The degree…
An evolutionary algorithm called 'differential evolution' is combined with Monte Carlo simulation to determine and optimize models of disordered crystal structures. Requirements for successfully finding the parameters describing disorder from diffuse scattering data are discussed and the algorithm is applied to resolv…
In this paper we show how it is possible to control the nature and the efficiency of collective photophysical processes in a network composed of two different fluorescent units organized on the surface of silica nanoparticles. Such a structure is obtained by covering nanoparticles with a layer of dansyl moieties (Dns)…
Atom positions and anisotropic Debye-Waller factors of the rhombohedral phase of LaCrO(3) have been refined simultaneously with the low-order structure factors, using a structure-analysis method of convergent-beam electron diffraction (CBED) proposed by Tsuda & Tanaka [Acta Cryst. (1999), A55, 939-954]. The method is…
High-resolution x-ray rocking diffraction has been used to measure the spontaneous strain associated with the cubic–rhombohedral phase transition in LaAlO 3 in the range 10K ≤ T ≤ 750 K. The data are consistent with a second-order Landau-like model at high temperatures, with T C = 834(2) K. At lower temperatures, the…