Materials Literature
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The aggregation of cyanine dyes on the surfaces of AgHal microcrystals is examined. It is shown that the photochemical activity of the aggregates in processes involving the spectral sensitisation of photographic materials is determined to a large extent by the occurrence of secondary dark reactions in which photoelect…
Die ungewöhnliche Oxidationsstufe +IV für Eisenzentren kann durch den porphyrinähnlichen Corrolliganden so stabilisiert werden, daß die Verbindungen 1 (R = CI, Ph, OFe‐Corrol) bei Raumtemperatur isolierbar sind. Das sauerstoffverbrückte zweikernige Eisen(IV)‐corrol, das sich leicht in die einkernigen Eisen(IV)‐corrole…
A powder sample of 2M 1 muscovite, (K 0.90 Na 0.07 )(Al 1.63 Fe 0.23 Mg 0.16 Ti 0.03 )(Si 3.20 Al 0.80 )O 10 (OH) 2 , was studied by time-of-flight neutron diffraction at 1 bar and at 2 (± 0.1) GPa. Rietveld refinements of the crystal structure were performed, varying all atomic coordinates in the room-pressure case (…
Vertauscht man eine β‐Methineinheit und das N‐Atom eines Pyrrolrings , erhält man den neuen Porphyrinisomertyp 1 , der durch Kondensation von Pyrrol und p ‐Tolylaldehyd entsteht. Als vierzähniger Ligand, d. h. über die drei N‐Atome und das C‐Atom des inneren Cyclus koordiniert 1 überraschenderweise Ni II ‐Ionen. Das G…
A network of alternating CoO 4 and PO 4 tetrahedra linked through corners is formed by the blue title compound. The Co II centers are exclusively in a tetrahedral environment, as the compound's color indicates. The channels, whose pore openings (with respect to Co and P atoms only) are regular octahedra in one directi…
The π–π* absorption edge (Q band) of the soluble porphyrin polymer 1 lies in the IR region and is unusually intense. Electroabsorption (Stark) spectra demonstrate that polymer 1 has an exceptionally large third-order nonlinear susceptibility.
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
The nuclear Ras-related protein Ran binds guanine nucleotide and is involved in cell cycle regulation. Models of the signal pathway predict Ran to be active as Ran.GTP at the initiation of S phase upon activation by the nucleotide exchange factor RCC1 and to be inactivated for the onset of mitosis by hydrolysis of bou…
EPR spectra attributed to Fe 3+ centres, produced by hole trapping at substitutional Fe 2+ ions, are observed below 250 K, in X-ray-irradiated CdCl 2 single crystals doped with 0.1 mol% Fe. The zero-field-splitting parameter b 2 0 decreases from 0.0818 cm -1 at 13 K to 0.0736 cm -1 at 225 K. Its absolute value and tem…
Abstract Polypropylene films were treated with the CHCI 3 plasma, and their chemical composition was analyzed with XPS and ART IR spectroscopy. The CHCI 3 plasma irradiation made polypropylene films hydrophilic. The advancing contact angle decreases from 95° for the untreated to about 73° for the CHCI 3 plasma‐treated…
Pure nuclear quadrupole resonance (NQR) of <SUP>14</SUP>N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to mag…
Tetragonal LaCo13−xSix compounds have been obtained by annealing cubic LaCo13−xSix compounds. The space group for the tetragonal structure is I4/mcm. Atomic ordering occurs in the tetragonal LaCo13−xSix compounds, i.e., Si atoms show a strong preference for occupying a specific crystallographic position. The tetragona…
(Ba0.5Sr0.5)TiO3 thin films were prepared by ion beam sputtering from powder targets with (Ba+Sr)/Ti ratios ranging from 0.80 to 1.50. All of the perovskite (Ba,Sr)TiO3 films were single phase except for the film with a (Ba+Sr)/Ti ratio of 1.41. The dielectric constant values notably depended on the (Ba+Sr)/Ti ratio f…
A negative dielectric anisotropy cholesteric liquid crystal, oriented homeotropically in a wedged capacitance cell, was subjected to an applied electric field. The Freedericksz transition threshold voltage was found to depend on the local thickness of the sample, and was found to vanish at a thickness of order 3/2 P,…
The enhancement of acoustic caviation at a liquid-solid interface following laser-induced bubble formation is studied. The experiment results indicate that metastable ultramicroscopic bubbles formed on the solid surface cause a long-term ``memory effect'' on acoustic cavitation. By performing a double-pulse experiment…
Abstract The chemical crosslink density (CLD) and network structure of natural rubber (NR) vulcanizates, modified with phosphorylated cardanol prepolymer (PCP), have been studied by equilibrium swelling and other chemical methods. The PCP‐modified NR vulcanizates showed lower CLD, as compared to the unmodified NR samp…
Hydrofluoric acid solutions containing high concentrations of the ion NO+ produce an etchant capable of reproducibly generating a porous silicon layer on both single-crystal and polycrystalline silicon surfaces. Room-temperature photoluminescence from porous silicon that has been chemically etched in such solutions ha…
The concentration fluctuations induced in a semidilute polymer solution by shear flow are directly visualized for the first time. The spatial structure of the ``butterfly pattern'' observed by light scattering is elucidated, being the result of hydrodynamic rippling waves which have a distribution of tilt angles. The…
Abstract The crystalline structure of chitosan membranes made of a high degree of (90%) and low degree of (60%) deacetylated chitin by various regeneration processes was studied. The results of X‐ray and IR spectroscopy investigations testify that the type of crystalline structre, the degree of crystallinity, and the…
Components of the extracellular matrix are believed to guide both nerve cells and neurites to their targets during embryogenesis and, therefore, might be useful for controlling regeneration of nervous tissue in adults. To study the influence of extracellular conditions on neurite outgrowth and cell motility, PC12 cell…