Materials Literature
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Considerable theoretical and experimental research on polluted insulators has yet to yield a perfect generalized mathematical model which can predict accurately critical flashover voltages and currents. In this paper an ac model has been proposed especially applicable to static arcs. The salient feature of the propose…
Iodination of 5,15-diphenylporphyrin followed by metallation and palladium(0) catalysed coupling with monosubstituted acetylenes gives zinc(II)-10-(2-substituted-alkynyl)-5,15-diphenylporphyrins.
A new approach to the controlled synthesis of hyperbranched polyesters, via copolymerisation of AB2 and B3 monomers, has been demonstrated. This technique allowed relatively easy production of new families of hyperbranched materials, circumventing the laborious and time-consuming syntheses required for their dendrimer…
In the paper change in iron losses due to the switching frequency in soft magnetic materials supplied by PWM inverter, is analyzed. Experimental tests with several samples of material and switching frequency from 1 kHz up to about 20 kHz, are reported. Values of iron losses vs switching frequency, for different values…
Hydrogen and deuterium trapping sites in high-strength steels have been observed by secondary ion mass spectrometry (SIMS). High-strength steels with 1400 MPa tensile strength are stressed and dipped in D2O and 20% NH4SCN solution at 323 K to occlude hydrogen and deuterium. Depth profiles by SIMS show the presence of…
To improve hydrodynamic journal bearing steady-stale and dynamic performance, a new bearing concept, the wave journal bearing, was developed at the author's lab. This concept features a waved inner bearing diameter. Compared to other alternative bearing geometries used to improve bearing performance such as spiral or…
The compressional and recovering curves of a fabric are considered to consist of three steps, respectively. The first and third steps of the compressional curve and the first step of the recovering curve are approximated by the linear equation (y = a + bx). The second steps of the compressional and recovering curves a…
In this paper we use arguments based on Picard-Fuchs equations and transversality of intersections of level curves to obtain an exact count of the number of stationary solutions of the one-dimensional Cahn-Hilliard equation with a cubic nonlinearity.
The luminescence properties of the compounds ABO4(A = Sb, Bi; B = Nb, Ta) and ABi2Nb2O9(A = Sr, Ba) are reported. The influence of the ns2 ions on the luminescence properties of the transition-metal oxo-compounds depends strongly on their coordination. The compound BiTaO4 may have potential as a material for electroma…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical Vapor Surface Modification of Porous Glass with Fluoroalkyl-Functionalized Silanes. 2. Resistance to WaterHiroaki Tada and Hirotsugu NagayamaCite this: Langmuir 1995, 11, 1, 136–142Publication Date (Print):January 1, 1995Publication History Published online1 May 200…
The effects of copper (Cu), silicon (Si), molybdenum (Mo), and nitrogen (N) as alloying elements on the microstructure and corrosion behavior of type 304 (UNS S30400) austenitic stainless steel (SS) in deaerated dilute acidic chloride (Cl–) solutions at 30°C and 60°C was investigated using potentiodynamic, scanning el…
The evolution of microstructure and activity in benzene hydrogenation of Pd/CeO2 catalysts, prepared from Pd chloride or Pd nitrate, upon reduction at 573–973 K has been studied by X-ray diffraction (XRD), selected-area electron diffraction (SAD), high-resolution transmission electron microscopy (HRTEM) and gas chroma…
Recent progress in modeling of transport phenomena during dendritic alloy solidification is reviewed. Starting from the basic theorems of volume averaging, a general multiphase modeling framework is outlined. This framework allows for the incorporation of a variety of microscale phenomena in the macroscopic transport…
The reduction of crystalline size and amorphization of graphite and diamond during agate and stainless ball-milling are investigated by Raman spectroscopy. The ultimate crystalline size of graphite, estimated by the Raman intensity ratio, of 2.5 nm for the agate ball-mill is smaller than that of 3.5 nm for the stainle…
Acetobacter produces a gelatinous membrane composed of a cellulose network when grown in liquid culture under static conditions. The oxygen tension in the gaseous phase was found to have an effect on cellulose production and on the physical properties of the membrane. Cellulose production was higher at oxygen tensions…
The photoelectrochemical (PEC) characteristics of thin films of ‘Q-state’ CdS semiconductor particles in arachidic acid Langmuir–Blodgett (LB) layers have been examined. Initially, ‘Q-state’ size CdS particles of ca. 2 nm were formed in the film and then progressively grown to ca. 10 nm by a cyclic sequence, which inv…
Sixtus-Tonks experiment for an amorphous Fe/sub 77.5/Si/sub 7.5/B/sub 15/ wire made by quenching in rotating water has been performed under a tensile stress /spl sigma/. The data are analyzed using the formula V/sub w/=S(H-H/sub 0/), where V/sub w/ is the axial wall velocity, H is the steady field, and S and H/sub 0/…
Thin SiO_2 layers were deposited on the surface of porous Vycor glass by alternating vapor phase reaction with SiCl_4 and H_2O. The membranes prepared by this technique had a H_2 permeance of 0.3-0.4 cm^3(STP)/(min•cm^2•atm) and a H_2:N_2 selectivity of 500-1000 at 600 °C. The SiCl_4 dosage at each silylation cycle, t…
A combination of results from x-ray and neutron diffraction is used to obtain structural information about the metal-oxygen coordination shell in oxide glasses. Two ways to extract structural parameters of the Me-O coordination are presented. The first variant is a direct combination of both distance correlation funct…
We report on molecular dynamics simulations for model polyethylene chains, varying in length from 30 to 1000 CH2 units. We found that a certain minimum chain length is required for the formation of stable folded-chain lamellae. The present calculations show that this occurs when the chains have more than 150 CH2 units…