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 largest isopolyoxotunstate ion known to date, W24O8424− (structure shown in the picture), isolated as the cesium salt, and a chainlike polyoxotungstate ion made up of planar W4O16 units, isolated as the sodium salt, hide behind the simple empirical formulas of the title compounds.
Samples of poly(ethylene-iso/terephthalate)-perfluoro polyether multiblock copolymers with perfluoropolyether (PFPE) segments of different lengths have been characterized for surface composition by XPS and angular dependent XPS in order to determine the influence of the length of the PFPE blocks on the surface segrega…
Vacuum-ultraviolet (VUV) radiation causes the dissociation of organic σ bonds such as the C−C and the C−H bonds in polyolefins. The radicals formed in this process were investigated by trapping with nitric oxide. PE, PP, and PS were irradiated in ultrahigh vacuum with the MgF 2 -filtered radiation of a hydrogen plasma…
A significant extension of the class of AgSe clusters is achieved with the synthesis of the title compounds. This confirms the concept that attaching organic ligands to the outer surface of the cluster hinders the formation of stable binary selenides. The protecting phosphane ligands have a great influence on the stru…
The lactose permease, encoded by the lacY gene of Escherichia coli, is an integral membrane protein that functions as a proton and lactose symporter. In this study, we have characterized a novel monodisperse, purified preparation of lactose permease, as well as functionally reconstituted lactose permease, using spectr…
Protein tyrosine phosphatases (PTPase) play important roles in the intracellular signal transduction pathways that regulate cell transformation, growth, and proliferation. Here, solvent accessibility is determined for backbone amide protons from various segments of wild-type Yersinia PTPase in the presence or absence…
Dynamic light scattering was used to study the particle formation in the dispersion polymerization of aniline hydrochloride. The organic polymers poly( N -vinylpyrrolidone) and hydroxypropylcellulose are compared with inorganic silica colloids in their role as steric stabilizers of polyaniline dispersions. The particl…
The surface chemistry of SO 2 on polycrystalline Sn, Pt(111), and a ( x )R30°-Sn/Pt(111) surface alloy has been investigated using synchrotron-based high-resolution photoemission and ab initio self-consistent field calculations. Metallic tin has a large chemical affinity for SO 2 . At 100−150 K, SO 2 disproportionates…
A new type of porphyrin array has been synthesized by the coupling of six porphyrin moieties to a central benzene core via an ether linkage. The resulting porphryin supermolecule has a diameter up to 80 Å and a mass of 8500 daltons. In solution, the six porphyrins around the central benzene ring arrange themselves int…
Zwei vielseitig anwendbare Lumineszenzionensonden für Kaliumionen wurden auf der Grundlage des „Ein- und Ausschaltens”︁ einer Gold-Gold-Wechselwirkung entwickelt. Nach Zugabe von Kaliumionen weisen die Gold(I)-Komplexe [Au2(R2PCH2PR2)(S-benzo[15]krone-5)2] (siehe Bild; R=Ph, Cyclohexyl; M+=K+) eine intensive rote Lumi…
At the limits of analytical investigation one finds the nanodimensional C60 graphite segment 1, which, thanks to its long-chain alkyl substituents, is soluble. Monolayers of 1 on graphite can be characterized by scanning tunneling microscopy.
A new, simple, and effective method to modify the surface of glass plate and quartz capillary tube by ultraviolet (UV) photopolymerization of N -isopropylacrylamide (NIPAAm) has been developed. A photosensitizer, silane coupling agent with the dithiocarbamate group, was synthesized by the condensation reaction between…
A large difference in the exchange rate of the coordinated water molecule is seen in solution for the diastereoisomers M and m of a europium(III) complex with an octadentate, neutral macrocyclic ligand (kex(M)<kex(m)). This finding is of high relevance to the design of more efficient contrast agents for magnetic reson…
Computational modeling reveals that, by substitutional modification of interplanar dihedral angles in a series of quinopyrans, both the optical absorption cross section and the first hyperpolarizability can be widely tuned in both frequency and magnitude. This is a promising structural control scheme for modulating mo…
The “staining” cluster–crown compound [Ru6C(CO)14(η6-C6H4C10H20O6)] verifies that the internal walls of mesoporous silica MCM-41 may be selectively functionalized with propylammonium groups (see picture). By the use of high-resolution transmission electron microscopy the presence and position of the cluster and also o…
Small aromatic thiol molecules HS−C 6 H 4 −X, where X = OH, COOH, NH 2, and CH 3, have been used to stabilize gold nanosized clusters. The physical properties of the surfactant-coated nanoparticles, both in solution and as thin films, were found to be dependent upon the nature of the functional group X. In particular…
Well-relaxed atomistic configurations of polydisperse, linear polyethylene (PE) melts, obtained with the end-bridging Monte Carlo algorithm, have been subjected to detailed molecular dynamics simulations in both the canonical ( NVE ) and microcanonical ( NVT ) ensembles. Three different systems have been investigated,…
In 1989, it was predicted that a change in dendritic shape to a nearly spherical one should occur upon increasing the generation number (Naylor, A. M.; Goddard, W. A., III; Kiefer, G. E.; Tomalia, D. A. J. Am. Chem. Soc. 1989, 111, 2339). The absence of long-range order required for X-ray analysis allowed only indirec…
Only about 200 μg of catalyst are required to identify the catalytically active materials on a combinatorial library of heterogeneous catalysts by IR thermography. The procedure is highly sensitive, and temperature differences arising from catalytic activity of hydrogenations and oxidations have been reliably detected…
Spin dependent single electron tunneling in ferromagnetic double junctions is analysed theoretically in the limit of sequential tunneling. The influence of discrete energy spectrum of the central electrode (island)on the spin accumulation, spin fluctuations and tunnel magnetoresistance is analysed numerically in the c…