Materials Literature
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Porous silicon formed by anodization of a p‐type silicon substrate is characterized by a distribution of crystallites with diameters smaller than about 100 Å. The corresponding size distributions obtained from Raman measurements show distinct peaks which are explained for the first time by the tunneling of holes throu…
Specimens of the 350 K (77°C) ternary eutectic of the Bi–In–Sn system were solidified unidirectionally at very low speeds and quenched to form a representative solid/liquid interface for subsequent study. From such interfaces, this eutectic was observed to be of the faceted–faceted–non-faceted type, freezing to form t…
Transmission electron microscopy investigations have been performed on SrxBa1-xNb2O6 (SBN x(1 - x)). Bright-field imaging of ⟨100⟩-oriented SBN 60/40 and 75/25 crystals revealed nanopolar domains with a strong shape anisotropy. The morphology of the nanopolar domains was needle like. Selected area electron diffraction…
Layered ceramic‐ceramic composites exhibit improved mechancial performance over monolithic composites, design flexibility for the solution of complex technological problems such as with functionally gradient materials (e.g. Al 2 O 3 /Y‐TZP, see Figure), and provide a model for the sudy of interfacial reactions between…
Abstract The monolith froth reactor, involving two‐phase flow and a monolith catalyst, is developed. The flow within monolith channels, consisting of trains of gas bubbles and liquid slugs, is produced by forming a two‐phase froth in a chamber immediately below the bottom of the monolith. The froth then flows upward i…
Abstract 2,6,6-Trimethyl-5-(2,5-dimethyl-3-furyl and -3-thienyl)-3-heptyn-2,5-diols were carbonylated in benzene in the presence of 1 : 1 — Pd(OAc)2/I2 as the catalyst. The reaction at 90 °C under 80 atm of carbon monoxide for 5 h directly gave both E and Z isomers of t-butyl-substituted furyl- or thienyl fulgides. Th…
The nuclear enzyme topoisomerase I (topo I) has been recently recognized as the target for the anticancer drug camptothecin (CPT; NSC 94600) and its derivatives. This drug has been reported to display effective antitumor effects on a variety of human tumor models xenografted in nude mice. However clinical studies of s…
It is well known that the highest elastic moduli reported for linear poly-mers are generally much smaller than their theoretical values. This has been shown particularly by Nakamae and coworkers [1]. For a range of poly-mers they have summarized their crystal moduli determined by x-ray dif-fraction as measured in the…
The SpectroMicroscopy Facility at the Advanced Light Source is based on a high brightness, high-resolution beamline, and includes a collection of projects designed to exploit the unique characteristics of the soft x-ray beam. The beamline itself is comprised of a 5-m long, 5-cm-period undulator, a spherical-grating mo…
Changes in appearance and in the chemical and mechanical properties of films of Liquitex acrylic gloss medium, a commercial artists' medium based on an acrylic polymer dispersion, have been studied during natural aging in the dark and in accelerated thermal and light exposure tests. In dark storage at room temperature…
Abstract Samples of poly(etherether ketone) (PEEK) were subjected to large plastic deformations under uniaxial tension and simple shear by means of a new video‐controlled testing method at constant true strain rate. The “equivalent” stress‐strain curves obtained under the two loading modes are close at the yield point…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTX-ray structure analysis of a wholly aromatic polyimide with a rigid-rod chainYutaka Obata, Kenji Okuyama, Sonoko Kurihara, Yukishige Kitano, and Takuma JindaCite this: Macromolecules 1995, 28, 5, 1547–1551Publication Date (Print):February 1, 1995Publication History Publishe…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTX-ray Structure of a New Hydrosol of Gold ClustersWalter Vogel, Daniel G. Duff, and Alfons BaikerCite this: Langmuir 1995, 11, 2, 401–404Publication Date (Print):February 1, 1995Publication History Published online1 May 2002Published inissue 1 February 1995https://doi.org/10…
The contrast in electron channeling patterns is quantitatively treated using a theory in which electrons in Bloch states excited by the incident electron are scattered through large angles by the fluctuation part of the potential (thermal diffuse scattering). The subsequent multiple elastic and inelastic scattering is…
Abstract Magnetic resonance imaging (MRI) is used to measure the time evolution of the volume fraction vs. height profile during batch sedimentation of rod‐like particle suspensions. At any instant during sedimentation, MRI clearly delineates the supernatant, suspension, and sediment regions. The rod‐like particles wi…
Theoretical potential‐pH equilibria and anodic polarization studies were used to show that formation of the aqueous complex in at ∼24°C promotes active behavior of copper at in a manner similar to that observed in chloride solutions. A region of apparent Tafel behavior is observed with a position and slope of 60 mV th…
The vibronic origin of ferroelectricity and structural phase transitions first suggested three decades ago, has been given recently new theoretical foundation and strong experimental evidence. It has been shown that for any polyatomic system, including crystals, the vibronic mixing of the ground electronic state of th…
3-Dimensional aromatic moiety was used for the first time in the synthesis of liquid crystals. Several of the prepared compounds, based on σ- aromatic boron clusters 1 and 2, show only nematic mesophases with relatively high Ti, good electrochemical but limited thermal stability. Absorption and emission spectra of pyr…
Abstract— The hematoporphyrin‐sensitized production of singlet molecular oxygen, O 2 ( 1 Δ g ), has been investigated in methanol and in aqueous solution. The quantum yield for formation of O 2 ( 1 Δ g ) (Φ Δ ) has been measured by both steady‐state (oxygen consumption) and time‐resolved (near‐infrared luminescence) m…
Abstract A finite element simulation is proposed for the shaping of glass fiber fabric. The overall mechanical behavior of the fabric is obtained by combining the tensile behavior of a single thread and the current position of threads in the fabric. The constitutive model for a single thread in tension is based on a s…