Materials Literature
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The collective behavior of a system of straight parallel dislocations is investigated. It is found by numerical simulation that the internal stress $\ensuremath{\tau}$ created by the dislocation has a stochastic component. In order to describe this stochastic character the form of the probability distribution function…
Abstract It is important to determine the existence and composition of homogeneous azeotropes in the analysis of phase behavior and in the synthesis and design of separation systems, from both theoretical and practical standpoints. A new method for reliably locating any and all homogeneous azeotropes for multicomponen…
Solid samples of polycrystalline corundum α -Al 2 O 3 activated by triply-charged rare-earth ions RE 3+ (R=Eu 3+ , Er 3+ , Pr 3+ ) were synthesized by the sol-gel technology. Characteristic narrow-line optical absorption and luminescence spectra produced by intraconfigurational 4 f -4 f transitions in RE 3+ ions have…
1. In this field study, diatom‐specific and bacteria‐specific fatty acids were used as biomarkers to evaluate the differences in diet between Chironomus plumosu s (a spring‐emerging cohort) and C. anthracinus (an autumn‐emerging cohort), and Procladius spp. Furthermore, total lipid content of Chironomus larvae was ana…
Electromagnetic levitation is used to undercool bulk samples of eutectic Ni 21.4 at % Si alloys. Large undercoolings ΔT up to ΔT=220 K are achieved by containerless processing of the melts. Crystal growth velocities are measured as a function of undercooling. The growth kinetics during solidification of the eutectic a…
The optical birefringence (Δ n ) and dielectric anisotropy (Δ ε ) of nematic liquid crystals were calculated using the well-known theories of Vuks and Maier-Meier, respectively. The molecular dipole moments and polarizabilities needed for the estimation were taken from semiempirical AM1 calculations. The calculated va…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTMaleic Anhydride Modified Polypropylene with Controllable Molecular Structure: New Synthetic Route via Borane-Terminated PolypropyleneBing Lu and T. C. ChungView Author Information Department of Materials Science and Engineering, Th…
The different generations of BOC-protected glycine-functionalized PAMAM dendrimers were studied, crystal structure of the 1st generation dendrimer was obtained, and the amt. of H bonds was estd. The x-ray structure shows multiple interactions between the different end groups of the dendrimer, modeling the shell of a h…
Chalcogenolates of the smaller lanthanides (Ln) react with elemental chalcogen to give the first examples of cubane clusters containing Ln ions. Both (py)8Yb4Se4(SePh)4 and (py)10Yb6S6(SPh)6 were isolated; the Se compound exhibits the familiar M4E4 structural motif, while the S compound is best described as a double c…
We etched thermally poled fused-silica coverslips in 49% HF for 30 s transverse to the poling direction to reveal structural details of the nonlinear region. A peaked ridge below the anode surface, corresponding to a slower etch rate than that of the bulk SiO(2) , was located approximately 5 microm below the anode sur…
Activated carbon fibers (ACF) are microporous carbon consisting of a three-dimensional network of micrographites having the size of ∼3 nm. We investigate structural and electronic properties of ACFs in relation to the adsorption of helium, nitrogen, and oxygen gases, by means of adsorption isotherm, ESR (electron spin…
The reaction of [Cu(CH(3)CN)(4)](BF(4)) with 3,5-dimethyl-4-nitropyrazole (Hdmnpz) in the presence of triethylamine yields the new copper(I) complexes [Cu(dmnpz)](3) (1) and (Et(3)NH)(2)[Cu(4)(dmnpz)(6)] (2), depending on the experimental conditions. The reactivity of 1 and 2 toward neutral ligands such as triphenylph…
An extended-core liquid crystal (LC) based on the 3,3′-di(acylamino)-2,2′-bipyridine unit is investigated with respect to its behavior in alkane solvents. It is demonstrated that the lyotropic mesomorphism observed in dodecane can be tuned by varying the concentration of the sample, and the columns can be switched in…
Vapour–liquid coexistence densities near the critical point are reported for polarizable water models, determined by a series of grand canonical Monte Carlo simulations with the histogram reweighting method. Previously proposed point charge models rescaled to match the experimental permanent dipole moment in the gas p…
Al 2 O 3 -, TiO 2 -, SiO 2 -, and ZrO 2 -based mixed-oxide supports were synthesized by sol−gel techniques using 2,4-pentanedione as the complexing/templating agent. These materials have been investigated by employing nitrogen adsorption, 27 Al, 29 Si, and 1 H solid-state magic-angle spinning nuclear magnetic resonanc…
Inhibition of copper corrosion in aerated 0.5 M sulfuric acid (H2SO4) solutions containing various concentrations of indole was studied in the temperature range from 25°C to 55°C using potentiodynamic curve, weight-loss, and analytical methods. Indole shifted corrosion potentials toward more noble values (i.e., it had…
Super-tough nylon 6 was prepared by using maleic anhydride grafted polyethylene-octene rubber/semicrystalline polyolefin blend (TPEg) as an impact modifier. The morphology, dynamic mechanical behavior, mechanical properties, and toughening mechanism were studied. Results indicate that TPEg with a semicrystalline polyo…
Broad-band UV absorption spectroscopy was used to determine radical densities in reactive gas plasmas generated in a 13.56 MHz capacitively coupled parallel plate reactor. Five radical species were detected: , CF, AlF, and . Absolute (line-integrated) densities were determined in and plasmas, as were the vibrational a…
The addition of tetraalkylammonium cations to aqueous silicate solutions enhances the abundance of symmetric, cagelike, polysilicate anions including the cubic octamer, Si(8)O(20)(8)(-). The equilibrium ratio of tetramethylammonium (TMA) cations to the octameric silicate anion is 8:1 for solutions with a concentration…
Earlier studies involving water-mediated transformations in lysozyme and ribonuclease A have shown that the overall movements in the protein molecule consequent to the reduction in the amount of surrounding water are similar to those that occur during enzyme action, thus highlighting the relationship among hydration,…