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。
57 Fe Mössbauer data are presented to show that polycrystalline samples of [Fe(dppen) 2 X 2 ]·2S, where dppen is cis-1,2-bis(diphenylphosphino)ethylene and X - is Cl - or Br - and S is CHCl 3 or CH 2 Cl 2, exhibit the light-induced excited spin state trapping (LIESST) effect. If the sample is kept at 10 K, Ar ion lase…
Several types of additives that contain transition metals can promote the cross-linking of poly(vinyl chloride) (PVC) by a mechanism that apparently involves reductive coupling of the polymer chains. In solid PVC, the cross-linking occurs at 200 °C, and model-compound experiments show that it can be ascribed to the pr…
The incorporation of two brominated compounds/antimony trioxide blends into a PP–PE copolymer were studied. Both brominated trimethylphenyl indane (FR 1808) and poly(pentabromobenzyl acrylate) (FR 1025) confer good flame retardancy at 40% loading. A comparison was made with the incorporation of magnesium hydroxide at…
Spontaneous and field-induced linear birefringence is measured at low temperatures on single-domained single crystals of weakly doped SrTiO3:Ca (x = 0·002 and 0·007) in order to investigate polar ordering processes near to Tc ≈ 4 and 18 K, respectively. In agreement with direct polarization measurements the size of me…
In recent years, coupled or hyphenated techniques have become popular, and have been successfully applied to the solution of many analytical problems. HPLC-MS, tandem MS-MS, GC-FTIR, TLC-FID, GC-MS, etc. are but a few of the familiar abbreviations used for these one step, “double analysis” techniques. The coupling of…
17 O nuclear magnetic resonance was used to investigate the classical two-step procedure for the preparation of sol−gel derived SiO 2 −TiO 2 or SiO 2 −ZrO 2 glasses. The formation of significant amount of Si−O−M bonds (M = Ti, Zr), resulting from the reaction of silanol groups with M−OR groups, was clearly demonstrate…
The effect of the precursor on the morphology, the structure, and the adsorption properties of the activated carbon in the case of poly(ethylene terephthalate) and cellulose, was studied. Scanning tunnel microscopy, X-ray scattering methods, and adsorption from gas and liquid phases were applied to answer the problem.…
The combination of the Knudsen cell with a standard cubic ICR trapping cell produces a number of cluster ions of molybdenum oxides Mo x O y + ( x = 1−5, y = 1−15). Ionization of molybdenum trioxide vapors by electron impact yields Mo x O y + with high oxygen-to-metal ratios. Collisions with vacuum gas lead to reductio…
The morphology of a liquid-crystalline ABA triblock copolymer with polystyrene (PS) blocks (12 vol %) and a side chain nematic liquid crystalline B block has been studied by TEM and temperature dependent SAXS measurements. Above the clearing temperature ( T c = 122 °C) the morphology is characterized by a body-centere…
We have linked two porphyrazinedithiolates of the type Ni[pz((S-)2:R6)] (R = 4-tert-butylphenyl) by mutual chelation of a nickel ion. The trinuclear metal-linked porphyrazine dimer 9 is a monoanion, and it exhibits the classical EPR signal of Ni(III) bis(dithiolene) complexes. The absorption spectrum of the Ni(III)-li…
Barium titanate (BaTiO 3 ) thin films that were derived from methoxypropoxide precursors were deposited onto (100) Si, Pt/Ti/SiO 2 /(100) Si, and molecular‐beam‐epitaxy‐grown (MBE‐grown) (100) BaTiO 3 on (100) Si substrates by spin coating. The crystallization behavior of the amorphous‐gel films was characterized usin…
We present measurements and theory of a fluid-solid phase transition at a hard, flat wall in a two-sized hard-sphere mixture. With particle concentrations well below the level for bulk phase separation, a fluid monolayer (enriched in the larger spheres) forms at the wall. At slightly higher concentrations, the wall-fl…
The synthesis of water-soluble, unsymmetrical, trisulfonated zinc phthalocyanines (ZnPcS3) as single products of the ring expansion of boron tri(4-sulfo)subphthalocyanine (SubPc) is reported. The novel, water-soluble trisulfo-SubPcB(OH) was prepared via hydrolysis of the tris(4-chlorosulfonyl)SubPcB(Br) which in turn…
Treatment of [Cu 2 (O 2 CCH 3 ) 4 (H 2 O) 2 ] with 2 equiv of di-2-pyridyl ketone (dpk) in methanol followed by addition of 1 equiv of NaClO 4 yields [Cu 4 (dpk·CH 3 O) 4 (CH 3 O) 2 ] (ClO 4 ) 2 ( 1 ) in ∼75% yield (dpk·CH 3 O - = the monoanion of the monomethylated diol of dpk). The same complex has also been isolate…
Oxygen nonstoichiometry of Ce 0.8 Gd 0.2 O 1.9 − x was gravimetrically measured at temperatures from 700 to 1000°C and oxygen partial pressures between 10 −24 and 1 atm. Based on the experimental data, the relationship between log x and log p O 2 , (where x is the oxygen deficiency and p O 2 the oxygen partial pressur…
It was demonstrated that porous aggregates of (NH 4 ) 3 PW 12 O 40 nanocrystallites were formed by epitaxial self-assembly, when dodecatungstophosphoric acid was precipitated by ammonium hydrogen carbonate in an aqueous solution. Scanning electron microscopy combined with nitrogen and argon adsorption measurements sho…
Laser-ablated Mn atoms react with O 2 to give MnO, OMnO, (MnO) 2, and MnO 2 - as major products, which are identified from oxygen isotopic substitution on their matrix infrared spectra. Annealing allows further association to form the cyclic Mn(O 2 ) complex, (O 2 )MnO and (O 2 )MnO 2 oxide complexes, and higher oxide…
We study the response of the magnetization to a time-dependent applied magnetic field $H(t)$ in a model for a uniaxial magnet. It is shown that a staircase structure in the magnetization curve results from Landau-Zener tunneling between different pairs of nearly-degenerate energy levels. This mechanism might be releva…
A series of comblike semiflexible polymers, in which the alkyl side chains were located nonsymmetrically on the ring, were synthesized by reacting hydroxypropylcellulose (HPC) with hexyl, octyl, dodecyl, and octadecyl isocyanates. Side-chain melting was observed in DSC experiments for polymers with 12 and 18 carbons i…
The structure, conformational behavior, and magnetic coupling constant of a prototypical organic molecular magnet (the bis(imino)nitroxide) have been investigated in vacuo and in solution, combining a recent density functional theory/Hartree−Fock model with a refined continuum description of the solvent. Comparison wi…