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。
Eine Alternative zu Porphyrinsystemen bieten Corrol-Liganden. Die Mangancorrole 1–4 beispielsweise sind leicht zugänglich, Redoxreaktionen finden bei ihnen am Metallzentrum (nicht am Liganden) statt, und insbesondere 4 zeigt beeindruckende katalytische Aktivität bei der Epoxidierung von Styrol mit Iodosylbenzol.
Abstract New and better mixing criteria are needed to assess dispersive and distributive mixing efficiency in polymer processing equipment. Such criteria can serve the purpose of process optimization and machine scale‐up. In this work, the history of flow strength and shear stresses experienced by a number of particle…
Agglomeration of noble metal particles has been a long-standing obstacle in the preparation of planar, finely dispersed, metal cluster−oxide support model catalyst systems. A solution deposition method was devised. Six-atom gold clusters, in the form of [Au 6 (PPh 3 ) 6 ][BF 4 ] 2 (Au 6 L 6 ), were deposited onto a Ti…
Abstract The relative growth rates of the three joint chains of silica tetrahedra and metal octahedra in the [100], [1̅10] and [1̅1̅0] directions within the mica layer (referring to the 1 M unit-cell) seem to control the morphology of mica crystallites. Laths and fibers are the products of relatively fast growth along…
Abstract Several macroscopic properties of degrading poly(lactic acid)‐b‐poly(ethylene glycol)‐b‐poly(lactic acid) (PLA‐b‐PEG‐b‐PLA) hydrogels were compared to one another as functions of degradation time. The specific hydrogel properties measured were the compressive modulus (K), the volumetric swelling ratio (Q), an…
A new class of liquid-crystalline epoxy resins containing azomethine and azo groups was synthesized and structurally characterized. The liquid crystal behavior of these compounds was characterized by differential scanning calorimetry (DSC), hot-stage polarized optical microscopy (POM) and wide-angle X-Ray diffraction…
The 2(3),9(10),16(17),23(24)-tetrasubstituted metalphthalocyanines 1-7 (M = In, Ni, Zn) were synthesized, as mixtures of four different structural isomers, from the corresponding 4-alkoxy-1,2-dicyanobenzenes and the appropriate metal salts. Separation of the four structural isomers was successfully achieved on a C30 a…
The pyridoxal 5'-phosphate-dependent enzyme cystathionine beta-lyase (CBL) catalyzes the penultimate step in the de novo biosynthesis of Met in microbes and plants. Absence of CBL in higher organisms makes it an important target for the development of antibiotics and herbicides. The three-dimensional structure of cyst…
The smectic properties of four series of dimer liquid crystals containing cholesteryl and biphenylyl groups were investigated by polarization microscopy, DSC and X-ray diffraction. Compounds that contain the strongly dipolar cyanobiphenylyl group exhibit a smectic layer spacing that is about 1.7 times the length of th…
Eight aromatic imine liquid crystalline (LC) diepoxides with dimeric architecture from readily available commercial reagents were synthesized and characterized by spectroscopic techniques. We characterized their liquid crystalline mesophases by differential scanning calorimetry (DSC), hot-stage polarized-light optical…
The fatigue of copper single crystals, oriented for single slip, was studied using electron channelling contrast imaging (ECCI) in a scanning electron microscope. This technique allows the detection and characterization of dislocation structures in bulk specimens. This paper presents ECCI images showing dislocation ar…
The first gene encoding a glucose dehydrogenase (GDH) from a halophilic organism has been sequenced. Amino acid sequence alignments of GDH from Haloferax mediterranei show a high degree of homology with the thermoacidophilic GDHs and with other enzymes from the medium chain dehydrogenase/reductase family. Heterologous…
Free-base and zinc(II) porphyrins bearing either one, two, or four hydroquinone entities at the meso positions are shown to bind quinones in solutions via a quinhydrone pairing mechanism. Electrochemical studies reveal that the quinhydrone complexes are stabilized by charge-transfer interactions between the donor (hyd…
A novel kind of soluble ladderlike poly(phenylsilsesquioxane) (LPPS) was prepared by stepwise coupling polymerization. Various techniques, such as fluorescence spectroscopy, X-ray diffraction (XRD), molecular simulation and calculation, were combined to indicate that the steric structure in LPPS was predominantly cis-…
The results of investigations of the Heusler alloys NiMnSb and ${\mathrm{Co}}_{2}\mathrm{MnSb}$ by magnetic circular dichroism in soft x-ray emission spectroscopy (SXEMCD) are presented. The data obtained are in a good agreement with theoretical calculations of x-ray emission. A very intense resonant inelastic peak in…
Abstract Using trimethylolpropane (TMP) and 2,2‐bishydroxymethylpropionic acid (Bis‐MPA), aliphatic hyperbranched polyesters (HBP) were synthesized, with a degree of branching of DB = 0.47 and a degree of polymerization of P n = 16.5. Aromatic HBPs with repetitive units of 2,2‐bis(4‐hydroxyphenyl)pivalonic acid (Bis‐P…
The temperature and pressure dependent conductivities of poly(4-vinylimidazole) (P4VI) blended with H3PO4 or H2SO4 have been studied. The influence of the temperature on the conductance and activation volume is discussed. The temperature dependent conductivity of the samples in the glassy state can be fitted with a si…
The nanometric scale allows an investigation of the Verwey transition: the impact of varying degree of oxidation of Fe cations on this transition was studied by means of zero-field-cooled superconducting quantum interference device measurements in nanometric highly nonstoichiometric particles of pure and Ti-substitute…
Summary The podzolization process is examined in the light of measurements of the solubility characteristics of aluminium fulvate, the extent of dissolution of a proto‐imogolite sol by fulvic acid, the adsorption capacity of proto‐imogolite for fulvic acid and aluminium fulvate, and published evidence. Fulvic acid at…
Hyperbranched aromatic polyamides (pPDT) from A 2 ( p-phenylene diamine)+ B 3 (trimesic acid) reactants have been prepared using direct polycondensation in solution. The influence of various polymerization parameters on the polymer structure development and the sol content, as well as on gel formation, has been thorou…