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71.
We construct the general coupling of nN = 2 Maxwell super-multiplets to N = 2 supergravity in five spacetime dimensions. In the case that the scalar field manifold is symmetric we find a complete classification based on Jordan algebras. Apart from the generic case there are also four “exceptional” cases associated with the Jordan algebras J3 of 3 × 3 hermitian matrices over the division algebras . Similar results follow for four dimensions, by dimensional reduction. 相似文献
72.
We construct the supersymmetric σ-model, in six dimensions, for an arbitrary hyper-Kähler manifold, and its minimal coupling to super-Yang-Mills theory. Non-trivial reduction to five or four dimensions yields the corresponding five- or four-dimensional N = 2 supersymmetric model with general scalar potential. We discuss briefly the coupling to supergravity in six dimensions and we give the on-shell supergravity torsion constraints. 相似文献
73.
Arlene A. Pascasio Cheryl E. Praeger Blessilda P. Raposa 《Designs, Codes and Cryptography》1996,8(1-2):173-179
We show that a non-symmetric nearly triply regular
designD with
and in which every line has at least q points is AG(n,q) for prime power q > 2 and positiveinteger n 3. 相似文献
74.
Dulce?Paloma?del J.?Gutiérrez-Hijar Fausto?Becerra J.?E.?Puig J.?Félix?Armando?Soltero-Martínez María?Belén?Sierra Pablo?C.?SchulzEmail author 《Colloid and polymer science》2004,283(1):74-83
The aggregation of two polymerisable surfactants dodecylethylmethacrylatedimethylammonium bromide (C12PS) and hexadecylethylmethacrylatedimethylammonium bromide (C16PS) was studied with a battery of methods. Both surfactants form premicelles at low concentration, and show a critical micelle concentration and a transition between spherical and rod-like micelles. The micelle ionization degree and the adsorption at the air/solution interface were also studied. Results are interpreted on the basis of the conformation of the polar head group. 相似文献
75.
Gómez-Gallego M Pellico D Ramírez-López P Mancheño MJ Romano S de la Torre MC Sierra MA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(20):5997-6005
The very low reduction potential of the chelate Fe(III)-EDDHA (EDDHA = ethylenediamine N,N'-bis(2-hydroxy)phenylacetic acid) makes it unreactive in photochemically or chemically induced electron transfer processes. The lack of reactivity of this complex toward light invalidates photodegradation as an alternative mechanism for environmental elimination. However, in spite of its low reduction potential, the biological reduction of Fe(III)-EDDHA is very effective. Based on electrochemical measurements, it is proposed that Fe(III)-EDDHA itself is not the substrate of the enzyme ferric chelate reductase. Likely, at the more acidic pH in the vicinity of the roots, the ferric chelate in a closed form (FeL-) could generate a vacant coordination site that leads to an open hexacoordinate species (FeHL) where the reduction of the metal by the enzyme takes place. 相似文献
76.
Fused tetracyclic oxetanes 4, highly substituted cyclobutenes 6, and the pentacyclic derivatives 7 and 8 were obtained by irradiation of derivatives 3 that were prepared from commercial R-(+)-sclareolide (1) in three steps. Compounds 4 are formed through a Paterno-Büchi reaction, while tricyclic derivatives 6 are the fragmentation products of the first formed oxetanes. In clear contrast, cyclopentenyl and 3-furyl derivatives, 3e and 3f, gave the [2+2] adducts, namely pentacyclic derivatives 7 and 8. All the reported reactions are totally regio- and stereoselective, with the exception of the cyclization of furyl derivative 3f, which gave the mixture of both the crossed (7b) and the right (8) isomers. 相似文献
77.
Martínez R Sierra B Redondo C Rayo MN Castaño F 《The Journal of chemical physics》2004,121(23):11653-11660
An experimental study is reported on the electron-impact total ionization cross sections (TICSs) of CCl4, CCl3F, CCl2F2, and CClF3 molecules. The kinetic energy of the colliding electrons was in the 10-85 eV range. TICSs were obtained as the sum of the partial ionization cross sections of all fragment ions, measured and identified in a linear double focusing time-of-flight mass spectrometer. The resulting TICS profiles--as a function of the electron-impact energy--have been compared both with those computed by ab initio and (semi)empirical methods and with the available experimental data. The computational methods used include the binary-encounter-Bethe (BEB) modified to include atoms with principal quantum numbers n> or =3, the Deutsch and M?rk (DM) formalism, and the modified additivity rule (MAR). It is concluded that both modified BEB and DM methods fit the experimental TICS for (CF4), CClF3, CCl2F2, CCl3F, and CCl4 to a high accuracy, in contrast with the poor accord of the MAR method. A discussion on the factors influencing the discrepancies of the fittings is presented. 相似文献
78.
Dr. Matthieu Fonvielle Dr. Inés Li de La Sierra‐Gallay Dr. Afaf H. El‐Sagheer Maxime Lecerf Delphine Patin Dr. Dénia Mellal Dr. Claudine Mayer Dr. Didier Blanot Dr. Nittaya Gale Dr. Tom Brown Dr. Herman van Tilbeurgh Dr. Mélanie Ethève‐Quelquejeu Dr. Michel Arthur 《Angewandte Chemie (International ed. in English)》2013,52(28):7278-7281
79.
Lithium-ion batteries are promising energy storage technology devices. They possess many advantages, including high energy density, flexible and lightweight construction and considerable durability. The rapid development of nanotechnologies can further improve their capacity, cycle life and safety. In this experiment, Li-ion diffusion in an all-solid lithium-ion battery (ASSLiB) was studied using the Neutron Depth Profiling (NDP) nuclear analytical technique. The thin ASSLiB system was synthesised by RF magnetron sputtering. The experiment showed that NDP is a very efficient experimental tool for direct analysis of Li distribution in Li batteries. It has been found that the depth profile of Li strongly depends on the state of charge of the battery. About one-third of the total number of Li in ASSLiB can move between the electrodes during charging / discharging. It has been also shown, using the multipixel detectors, that the lateral distribution of Li in ASSLiB is not homogeneous. This can mean, for example, that the position of Li is affected by structural defects that may arise due to variation of the volume or stress of the battery during charging or discharging. In the work are presented first results of measurements performed on ASSLiB of a 1?µm thickness. 相似文献
80.
Pamela Sierra Garcia Carlos Henrique Scuracchio Sandra Andrea Cruz 《Polymer Testing》2013,32(7):1237-1243
Rheological measurements were conducted to verify the influence of different mechanical recycling processes and the presence of contaminants on the degradation of post-consumer polypropylene. Firstly, polypropylene (PP) was contaminated to simulate a post-consumer material, following the protocol recommended by the FDA. PP was subsequently recovered (washed and dried) and the samples were submitted to different extrusion processes. The rheological data demonstrated that the different types of processing applied and the presence of contaminants altered the molecular structure of the samples. The contaminants acted as agents that accelerated the polymer degradation. The contaminated samples submitted to higher shear rates exhibited greater decrease in their molar mass and a slight narrowing in the molar mass distribution. Also, it was observed that the most degraded samples showed decrease in their molar mass, in the viscosity and in the level of their molecular entanglements. These samples also exhibited a more Newtonian behavior and their molar mass distribution showed a slight narrowing. By calculating the ratio of the molar mass it was possible to quantify the degree of degradation of PP samples, confirming the results obtained. 相似文献