Materials Literature
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Abstract The acid‐catalyzed formation of pyrrole derivatives from 1,4‐dicarbonyl compounds and ammonia or primary amines is generally known as the Paal–Knorr pyrrole synthesis. This reaction provides a general route for pyrrole derivatives from a variety of 1,4‐dicarbonyl compounds and primary amines. The mechanistic…
Abstract The one‐pot synthesis of porphine or isoporphine by the thermal condensation of aldehydes with pyrroles is generally referred to as the Rothemund condensation. Currently, this reaction being used for the synthesis of porphyrins, especially for 5,10,15,20‐, (or α,β,γ,δ‐) tetrasubstituted hindered meso ‐porphyr…
Abstract The photo‐initiated rearrangement of phenyl or aryl esters is generally known as the photo‐Fries rearrangement or photo‐Fries reaction and usually carried out in an aprotic solvent. This reaction is affected by electronic nature of substrate as well as the reaction environment and no apparent isotopic effect…
Recently a new class of Monte Carlo methods, called Time Relaxed Monte Carlo (TRMC), designed for the simulation of the Boltzmann equation close to fluid regimes have been introduced. A generalized Wild sum expansion of the solution is at the basis of the simulation schemes. After a splitting of the equation the time…
Abstract Electronic properties have been calculated for derivatives of long lived Cu(I) metallocyclophanes, which are self‐assembling coordination complexes that have metal–ligand charge‐transfer excited states. The molecules studied here are not the typical linear push–pull type with electron withdrawing and donating…
The aims of this study were to form uncompressed thermobonded 3D wool nonwoven shell structures in one continuous process, and to study the controlling factors that govern this process. Lack of bonding between wool fibres and between wool and thermoplastic fibres was attributed to the wool fibre?s low surface energy b…
Abstract The formation of a nitroalkane from the reaction between an alkyl halide and silver nitrite is known as the Victor Meyer reaction. All the mechanistic features and reaction's conditions have been discussed. The study finds that the ratio of nitroalkane and alkylnitrite varies, depending on the nature of alkyl…
Abstract Raney nickel is a porous nickel suspension primarily prepared from alkali soaking of 50% nickel‐aluminum alloy but can also be prepared by acid soaking (e.g., HCl). According to the temperature and alkali concentration, different types of Raney nickel can be prepared. The study finds that Raney nickels retain…
Abstract The Jacobsen and Katsuki have reported the improvement of olefin epoxidation, using a sophisticated chiral salen ligand for manganese complexes, which resulted in high enantioselectivity. They extensively studied different facets of this reaction to convert it into one of the most useful and widely applicable…
Abstract This reaction is a photo‐induced [2 + 2] cycloaddition of carbonyl compounds with olefins or other unsaturated substrates to form four‐membered cyclic ethers, known as oxetanes, with high regio‐ and stereoselectivity and is known as the Paterno–Büchi reaction. This reaction is often sluggish and also competes…
Abstract The Kolbe electrolysis involves the formation of symmetrical hydrocarbons through the coupling of radicals generated from carboxylic acid at an anode via electrolysis. The study shows that the free radicals have been used to initiate the polymerization for the preparation of low molecular weight polystyrene a…
Abstract This reaction involves a Lewis acid of an early transition metal (e.g., Ti, Zr, V, etc.) to catalyze the polymerization of vinyl monomers in the presence of trialkylaluminum to form stereoregulated or tactic polymers, and is generally known as the Ziegler–Natta polymerization or Ziegler–Natta olefin polymeriz…
We investigate theoretically the adhesion and electronic properties of graphene on a muscovite mica surface using the density functional theory (DFT) with van der Waals (vdW) interactions taken into account (the vdW-DF approach). We found that irregularities in the local structure of cleaved mica surface provide diffe…
Los nanotubos de carbono (CNTs, carbon nanotubes) son moleculas tubulares cuyo diametro es de escala nanometrica y cuyas paredes estan formadas por capas monoatomicas de carbono. Su estructura en combinacion con su morfologia unidimensional confieren unas propiedades muy especiales que hacen de los CNTs un material mu…
Abstract This reaction is a one‐step industrial production of butadiene from ethanol at temperature of 400–450°C in the presence of a catalyst with both dehydration and dehydrogenation processes and is generally known as the Lebedev process. The best catalyst for this process has been reported to be a silica gel impre…
A large quantity of linear strain and LCTE data from -55°C to 75°C on LX-17, PBX 9502 and ultrafine TATB (ufTATB) is presented. Axial and diametral measurements are blended to give final densities, which agree with the liquid immersion values of Baytos, et. al. The nominal densities at 21, -55 and 75°C in g cm-3 are:…
desse mestrado e à Fundação de Amparo à Pesquisa do Estado de São
Based on the complexity and difficult understanding on low-temperature resistivity minimum in manganites, the effect of ferroelectric-poling-induced strain on Kondo-type transport behavior was systemically investigated as a function of magnetic field for ${\text{La}}_{0.7}{\text{Ca}}_{0.15}{\text{Sr}}_{0.15}{\text{MnO…
The first artificial satellite, Sputnik 1, was launched by the USSR on 4 October 1957 in a low elliptical orbit and re-entered into the atmosphere after about 3 months. Since then the exploitation of the space around the Earth lead to an over-crowding of the Earth orbit, producing somehow an environmental problem. Man…
L’expérience en microgravité BAMBI (Bifurcation Anomalies in Marangoni-Bénard Instabilities) a volé à bord du satellite FOTON-M2 en juin 2005. Pendant les 4 jours disponibles pour l’expérience, une couche d’huile de silicone (200 cSt) de 5 mm d’épaisseur et de 10x10cm de largeur, en contact avec une couche similaire d…