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。
Abstract This paper compares the results of 27 Al nuclear magnetic resonance spectroscopy (NMR) and Al-K-edge X-ray Absorption Near Edge Structure (XANES) of natural imogolite and allophanes and some crystalline reference minerals. All soil allophanes studied contain 4-coordinated Al (Al IV ). The highest relative pro…
The crystallographic structure of BaTiO 3 particles prepared by conventional solid‐state reaction has been investigated by X‐ray diffractometry and dielectric measurements. The systematic analysis of the diffraction pattern has clearly shown the coexistence of tetragonal and cubic phases at room temperature. The relat…
Proteins of the glucose-starvation stimulon were identified by using two-dimensional gel electrophoresis and the gene-protein database of Escherichia coli. Members of this stimulon included enzymes of the Embden-Meyerhof-Parnas (EMP) pathway, phosphotransacetylase (Pta) and acetate kinase (AckA) of the acetyl phosphat…
ADVERTISEMENT RETURN TO ISSUEPREVArticleFerromagnetic Interactions in the First Bis(.mu.-end-on-azido)manganese(II) Dinuclear Compound: [Mn(terpy)(N3)2]2.cntdot.2H2ORoberto Cortes, J. Luis Pizarro, Luis Lezama, M. Isabel Arriortua, and Teofilo RojoCite this: Inorg. Chem. 1994, 33, 12, 2697–2700Publication Date (Print)…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelf-Assembling Porphyrin [2]-CatenanesMaxwell J. Gunter, David C. R. Hockless, Martin R. Johnston, Brian W. Skelton, and Allan H. WhiteCite this: J. Am. Chem. Soc. 1994, 116, 11, 4810–4823Publication Date (Print):June 1, 1994Publication History Published online1 May 2002Pub…
We have measured low-frequency Raman scattering (RS) spectra of the glass formers ${\mathrm{B}}_{2}$${\mathrm{O}}_{3}$, glycerol, m-tricresyl phosphate (m-TCP), and ${\mathrm{K}}_{3}$${\mathrm{Ca}}_{2}$(${\mathrm{NO}}_{3}$${)}_{7}$ in a broad temperature range above the glass transition temperature. The basic differen…
Crystals of gamma-chymotrypsin grown in aqueous solution were soaked in n-hexane, and the structures of both the soaked and the native crystals were determined to 2.2-A resolution. Seven hexane molecules and 130 water molecules were found in the hexane-soaked crystals. Two of the seven hexane molecules are found near…
We have synthesized single-layer carbon nanotubes by co-vaporizing cobalt with carbon in an arc fullerene \ngenerator and have identified conditions that lead to high yields. The diameter distribution of the tubes and \ntheir morphologies are studied using transmission electron microscopy. For nanotubes produc…
Abstract The synthesis of poly(2,5‐dialkoxy‐ p ‐phenylene)s (PPP) by palladium‐catalyzed polycondensation of 2,5‐dialkoxy‐4‐bromophenylboronic acids is described. Number‐average degrees of polymerization of ca. 30 have been reached at best. The characterization of the polymers by NMR, IR, UV‐VIS and fluorescence spect…
Novel monomeric, oligomeric, and polymeric charge‐transfer complexes with interesting electrical conductivity properties and even exhibiting superconductivity are expected to be obtainable by the systematic chemical modification of extended tetrathiafulvalenes (see Figure for one example). The synthesis and cyclic vol…
Abstract Dicopper(II) hydroxide tris(pyrazolide)s Cu2(OH)(4-Xpz)3 (pz = pyrazolide ion; X = H, CH3, Cl, Br) and Cu2(OH)(4-Xpz)3(4-XpzH)2 (X = Cl, Br) were prepared and characterized by means of magnetic susceptibility and IR spectroscopy. Their magnetic-moment values increased in the substituent sequence X = CH3 &…
Abstract Compounds based on poly(vinyl chloride) (PVC), and containing CaCO 3 filler and trifunctional acrylic crosslinking agent have been crosslinked by exposure to γ‐rays at dosages to 70 kGy. The crosslinking agent was found to be essential for crosslinking to proceed, only minor sensitivity to the irradiation hav…
Five copper‐nickel alloys with nickel contents ranging from 0 weight percent (w/o) to 100 w/o were electrochemically investigated in sulfide polluted seawater (0 to 100 ppm S = ). In addition a chromium modified copper‐nickel alloy (CDA 722) was also investigated. The purpose of this research is to investigate the eff…
Abstract Kaolinite was hydrothermally synthesized from two kinds of silica-alumina gels to examine the effect of the structure of the starting material. Two kinds of gels were prepared by precipitation at different pH conditions (pH = 9.6 and 4.2) from solutions containing water glass and aluminum sulfate. Na ions in…
Advanced polymer/nanoparticle composites are currently of great interest because of their unique properties. The bulk properties of these materials are strongly influenced by the nature of the ultrafine filler particles–including their dispersion. A technique is presented for the de‐agglomeration of chemically synthes…
Prebreakdown phenomena in n-hexane are observed in detail for positive and negative polarities by using simultaneously a high speed schlieren technique and an LED current measuring system, when an impulse voltage (1.1/225 /spl mu/s) is applied to a point-to-plane electrode gap. Furthermore, the effects of several addi…
Abstract Recent pedological evidence of the widespread distribution of beidellites in soils indicates the need for a greater knowledge of the effect of charge location on the microstructural organization of Na + smectite in gels. After equilibration at a suction pressure of 3.2 kPa before and after desiccation, TEM ob…
Summary Köhler illumination is the most favourable design for the illumination path of an electron microscope with a condenser objective lens. The new illumination system of the EM 910 and EM 912 OMEGA allows both wide area (Köhler) illumination for TEM operation and spot illumination for analytical investigations. Co…
The optical-absorption transitions originating from the lowest 4f5d excited state of ${\mathrm{Pr}}^{3+}$ in ${\mathrm{Y}}_{3}$${\mathrm{Al}}_{5}$${\mathrm{O}}_{12}$ have been studied. The experimental arrangement uses a 7-ns 266-nm light pulse to populate the lowest 4f5d state, and a spatially overlapped, time-sequen…
Abstract The effects of crystallinity, orientation, and short‐fiber filler on the thermal diffusivity D and thermal conductivity K of poly (ether ether ketone) (PEEK) have been studied. Below the glass transition, D increases by less than 10% as the crystallinity increases from 0 to 0.3. For amorphous PEEK, there is a…