Materials Literature
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A novel macroscopic stripe texture has been observed in freely suspended films of nonchiral liquid crystal, uniform stripes of alternating molecular orientation form spontaneously at the smectic-C--to--surface-hexatic phase transition and broaden with decreasing temperature. The stripes are identified as splay domains…
In this letter we show that UV illumination of porous silicon causes a decrease in its luminescence efficiency. Infrared measurements allow us to associate the efficiency decrease with a loss of hydrogen from the silicon surface. We also find that the rate at which the luminescence intensity degrades increases rapidly…
Using an ac calorimetry technique we measured the specific heat at the nematic-isotropic, smectic-A--nematic, and smectic-A--isotropic phase transitions, for the alkylcyanobiphenyl liquid crystal nCB series confined to the 0.2-\ensuremath{\mu}m-diam pores of Anopore membranes. Studies were also performed as a function…
A new kind of microcrystalline composite films consisting of diamond and cubic silicon carbide (β-SiC) has been synthesized in a microwave plasma assisted chemical vapor deposition process (MWCVD), using a gas mixture of hydrogen, methane, and tetramethylsilane. Single crystalline (111) silicon wafers and polycrystall…
Abstract We show that the subglass secondary relaxation temperature at which a polymer changes from brittle (crazing) to ductile (yielding) behavior is a function of the characteristic ratio C ∞ (which is a measure of the intrinsic flexibility and rigidity of a coiled chain). At 1 Hz frequency, the correlation is give…
Abstract Samples of a high‐purity isotactic polypropylene (iPP) were quenched from the melt so as to monitor cooling history. A continuous variation of morphology and crystal structure was obtained with cooling rate. This is discussed in relation to sample thermal history evidencing that cooling history relevant to qu…
The Ni 2p and O 1s XPS of NiO single crystals were measured using monochromatic Al K alpha radiation. Different treatments of the crystals allow the authors to give a description of the influence of defects on these spectra. The Ni 2p 3/2 spectrum of in-situ-cleaved NiO exhibits clearly visible features at 854.1 ev 85…
The selective seeding of palladium catalysts by photoirradiation for electroless copper plating was investigated. Pd(II) complexes, such as Pd(II)‐malate, ‐citrate, ‐tartrate, and ‐glucoheptonate, are effectively converted to Pd(0) catalysts by photoirradiation on an alumina substrate. The photoreduction of the adsorb…
Trajectories of secondary electrons (SEs) as an image signal in scanning electron microscopy are studied analytically in high-aspect-ratio submicron wide infinite trenches. It is found that the SE collection efficiency ξ, which is defined as the ratio of the number of SEs exiting the trench top surface divided by that…
Diffusion, permeation and trapping of deuterium in nickel exposed to a deuterium plasma were studied experimentally at temperatures of 455 to 568 K. One side of a nickel membrane was exposed to the plasma and the plasma-driven permeation was monitored. A beam of 3He irradiated the same side simultaneously to observe d…
Therapy with monoclonal antibody conjugates has been proposed for patients with malignant intracranial tumors and meningeal carcinomatosis. One obstacle to successful immunotherapy has been the inability of adequate quantities of antibody to reach and bind malignant cells. The use of superparamagnetic antibody micropa…
The kinetics of radiation defect accumulation and subsequent recovery during/after electron irradiation below 273 K, at 323 K and 373 K were investigated for the Fe-15.7 at.% Cr using positron annihilation measurements at room temperature. Formation of vacancy clusters was observed at all of the irradiation temperatur…
We propose the use of metal-insulator films as neutral density filters for spectrophotometric calibration in the UV and visible ranges. We present a theoretical approach to the design of such filters and show that the correct selection of starting metallic material as well as filling fraction and filter thickness is i…
Orbital ordering in crystals with degenerate localized levels ${\mathit{E}}_{\mathit{g}}$ and ${\mathit{T}}_{2\mathit{g}}$ is investigated on the basis of the symmetry of atomic density matrices and their transformation properties. During ordering processes, several kinds of local state can be stabilized, among which…
Abstract The reduction of risks associated with chemical processing operations is essential for the safe operation of chemical plants. The reduction of these risks is accomplished through a comprehensive process safety management program. Key elements of this program include Hazard and Operability Studies, Emergency R…
Abstract Erstmals wurden Einkristalle von farblosem RbKS durch Tempern eines äquimolaren Gemenges aus Kaliumsulfid und Rubidiumsulfid bei 820 K er‐ halten. Die sehr hygroskopische salzartige Verbindung kristallisiert orthorhombisch, Raumgruppe Pnma, a = 822,2(3), b = 504,3(4), c = 945,2(2)pm, Z = 4 im anti‐PbC1 2 ,‐St…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh-pressure phase transition in lithium deuteroxide: a neutron powder diffraction and vibrational spectroscopic studyDavid M. Adams, Andrew G. Christy, and Julian HainesCite this: J. Phys. Chem. 1992, 96, 20, 8173–8176Publication Date (Print):October 1, 1992Publication His…
The compounds Mg 2 Ni 3 P and Mg 2 Ni 3 As were prepared by heating the elements. Their structures have been determined from single-crystal X-ray data. The structure of the phosphide is a rhombohedral ternary variant of the cubic Laves structure type MgCu 2 (R 3̄ m; hexagonal lattice constants: a = 4.971(0) Å, c = 10.…
Abstract Die Röntgen‐Absorptionsspektroskopie an Oberflächen ist eine Methode zur Bestimmung der lokalen Geometrie adsorbierter Atome und Moleküle und damit eine Methode der „Oberflächen‐Kristallographie”︁. Sie wurde erst durch den Bau leistungsfähiger Synchrotron‐Strahlungsquellen möglich, die ein intensives und über…
Microstructural characterization of a high‐Al 2 O 3 substrate containing cofired thick‐film tungsten metallization, with particular emphasis on the metal/ceramic interface, was conducted. The substrate contained tabular Al 2 O 3 grains surrounded by a continuous calcium magnesium aluminum silicate glass containing par…