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。
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…
This article describes a hybrid electrostatic–aerodynamic levitation furnace for the containerless processing and study of oxide materials on the ground. Its operation principle relies on an aerodynamic levitator that allows sufficient electric charge to be accumulated on a sample, due to high-temperature heating, bef…
Nanotube fibers with diameters ranging between 10 and 100 microns were produced by a simple spinning process. These fibers were studied by x-ray scattering--a technique that allows good visualization of the composition as well as the alignment of the constituents. The fibers were found to be composed of bundles of sin…
Uniform silicon single nanodots were synthesized by laser ablation with a differential mobility analyzer (DMA) technique. The Si nanoparticles generated by laser irradiation of a silicon target were actively classified by a DMA and were impacted on the solid surface by a “nanoparticle beam”. By measuring the current o…
The synthesis, crystal structure, and spectroscopic and magnetic properties of a new alternating ferro- and antiferromagnetic, one-dimensional manganese(II) azide complex, [Mn(dpa)(N3)2] (where dpa is the 2,2′-dipyridylamine ligand), are reported. The compound’s crystal structure has been resolved at room temperature.…
Texture formation via high‐temperature deformation in sintered alumina was investigated. Fine‐grained, normal‐purity‐alumina sintered bodies deformed under stresses up to 80 MPa in a temperature range of 1200°–1300°C. Fine, disklike grains formed in the equiaxial fine‐grained matrix during high‐temperature deformation…
Abstract Three series of neat resins, based on methacrylates or dimethacrylates modified with 1‐[3‐(methacryl)propyl]‐3,5,7,9,11,13,15‐heptacyclopentylpentacyclo[9.5.113,9.15,15.17,13]octasiloxane (Methacryl‐POSS or POSS‐MA), were evaluated. Incorporation of POSS‐MA into the polymeric matrix was accomplished in three…
The occurrence of brittle fracture in iridium has attracted significant attention in recent years and is thought to be related to the energetics of the dislocation core, in particular the extremely high unstable stacking energy. Although it is not experimentally possible to measure the unstable stacking energy, first-…
The data on the number of active centers (Cp) and values of propagation rate constants (Kp) have been obtained for stereospecific and non-stereospecific centers at propylene polymerization with catalytic systems of various composition: TiCl3-AlEt3 (I), TiCl4/D/MgCl2-AlEt3 (II), TiCl4 /D/MgCl2-AlEt3-TES (III), where D…