Materials Literature
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A survey of the instabilities of switching voltage regulators with different types of current-mode controllers (including LC3or constant-hysteresis; MC2or constant-frequency and constant off-time versions) is presented. Apart from the well-known open-loop oscillation of the constant frequency regulator above 50% duty…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAmination of .pi.-allylpalladium chloride complexes. A mechanistic studyBjorn Åkermark, Gunilla Åkermark, Louis S. Hegedus, and Krister ZetterbergCite this: J. Am. Chem. Soc. 1981, 103, 11, 3037–3040Publication Date (Print):June 1, 1981Publication History Published online1 M…
A systematic comparative study of several series of chemically neighbouring compounds apt to give a reentrant mesomorphism is proposed. Experimental data concerning the various reentrant phases are summed up. From these observations various factors favourable to the occurence of the reentrance are revealed. Thus, the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanisms of thermal decomposition of diethylbis(triethylphosphine)platinum(II)Thomas J. McCarthy, Ralph G. Nuzzo, and George M. WhitesidesCite this: J. Am. Chem. Soc. 1981, 103, 12, 3396–3403Publication Date (Print):June 1, 1981Publication History Published online1 May 200…
A method is described for measuring the mass/length or mass of molecular assemblies by comparative electron scattering in the STEM. Standard particles whose mass is well established (e.g. TMV or fd bacteriophage) are deposited on the electron microscope grid together with the sample to be measured. Images containing a…
The luminescence properties of the Bi 3+ ion as an activator in the series of compounds and vary considerably with the host lattice composition. The Stokes shift of the emission varies from 1500 cm −1 in the case of to 12,800 cm −1 in the case of . The large variation of the position of the emission band is ascribed t…
Raman scattering and optical depolarization measurements have been employed in investigations of the phase transition induced by the substitution of lithium for potassium in KTa${\mathrm{O}}_{3}$ to form ${\mathrm{K}}_{1\ensuremath{-}x}{\mathrm{Li}}_{x}\mathrm{Ta}{\mathrm{O}}_{3}$. Lithium concentrations as high as 5.…
Abstract Various microwave plasma treatments were applied to Kevlar in the form of multifilament fabric and single fiber. Plasma‐modified fabrics were used to construct two‐ply laminates using a triazine resin adhesive. Very significant increases in the bond strength of laminates may be attributed to the plasma treatm…
We present a method for measuring linear electrooptic coefficients involving comparative measurement of interferometric phase-modulation indices at wavelength λ = 6328 Å. The accuracy of the method (8–16%) varies according to the crystalline quality. We have investigated a new nonlinear crystal, 3-methyl 4-nitropyridi…
We present a novel electrostatic, energy-dispersive particle analyzer whose astigmatism can be used to measure the polar angle distribution of charged particles originating in a sample spot, in a multichanneling mode. The analyzer consists of a toroidal prism and a truncated conical lens, both coaxial on an axis throu…
Abstract A new series of aromatic‐aliphatic polyesters of general structure: magnified image R 1 = terphenyl, biphenyl, stilbene R 2 = (CH 2 ) n ; CH 2 C(Me) 2 CH 2 ;CH 2 ;C(Et) 2 CH 2 ; (CH 2 CH 2 O) n CH 2 CH 2 has been synthesised. The existence of thermotrpic liquid crystalline phases has been shown…
Abstract Details of the thermal behavior, including transition temperatures, transition heats and transition entropies, are reported for three series of nematic liquid‐crystalline “backbone” polyesters having the general structure magnified image All polysters described above were examined by differential scanning cal…
A relationship Is(φ) that is valid for arbitrary temperatures T ≲ Tc and thicknesses of d of the N layer is established for clean SNS sandwiches in the case when the Fermi velocities of the normal (vN) and the superconducting (vs) metals are related by the strong inequality vN ≪ vs. Dependences of the critical current…
The performance of insulators as determined by artificial tests for various contaminant levels at voltage levels ranging from 200 to 1000 kV dc are presented along with comparisons to field measurements. Included are the effects of polarity, insulator shed design, insulator spacing, and uniform and non-uniform contami…
Some experiments are reported on the bubble textures obtained in homeotropically aligned cholesterics of large pitch. The variations of the bubble diameter with the thickness and the temperature of the liquid crystal and with an applied electric field are studied. The conditions of the texture erasure by application o…
The fluorescent emission and scattering spectra of metallic lithium and lithium fluoride were obtained by using continuous radiation from the Institute for Nuclear Study synchrotron in the energy region of 40-80 eV. The spectrum of metallic lithium is in close resemblance with the one obtained by an ordinary electron…
Electron microscopy and diffraction techniques for studying grain‐boundary structure are reviewed. The experimental conditions for applying strong‐beam, weak‐beam, and lattice imaging and electron diffraction are described and examples from recent studies in ceramics, semiconductors, and metals are used to illustrate…
Warburg’s law, which describes the distribution of the current density over the plane electrode for a point to plane steady corona discharge, is derived. The derivation is based on a model using hyperboloid point to plane geometry with a constant charge carrier mobility model and a time independent potential. The deri…
Co 6 C(CO) 12 S 2 (I) has been isolated in crystalline form from the mixture of more than a dozen of carbonyl products formed when Co 2 (CO) 8 reacts at room temperature with CS 2 . Crystals of I are monoclinic with space group Cc , and lattice constants a 16.250(5), b 9.413(4), c 16.036(5) Å, β 116.77(4)°. St…
Abstract Small‐scale qualitative tests were used to screen 185 inorganic powders for flame and inhibiting effects upon cellulose. Nearly half of the compounds inhibited smoldering. These were limited to inorganic salts whose anions include boron, phosphorus, sulfur or halogen. Over half the compounds inhibited flaming…