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21.
Dr. Deise M. Pereira de Oliveira Santos Marilia G. Belarmino Cabral Ahmed Bentaleb Prof. Dr. Rodrigo Cristiano Prof. Dr. Hugo Gallardo Dr. Fabien Durola Dr. Harald Bock 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(22):7389-7393
Whereas perylene tetracarboxdiimides derived from amino‐n‐alkanes if at all only show monotropic (thermodynamically unstable) mesogenic self‐assembly, the hexagonal columnar liquid crystalline state can be stabilized over a broad temperature range with doubly branched, doubly racemic alkyl residues. An improved tendency to homeotropic surface orientation is observed, and the orientation of the liquid crystalline domains is maintained upon cycling through the crystalline state at room temperature. 相似文献
22.
We establish a precise estimate of the ultimate bound of solutions to some second order evolution equations with possibly unbounded linear damping and bounded forcing term. 相似文献
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24.
From Mesomorphic Phosphine Oxide to Clustomesogens Containing Molybdenum and Tungsten Octahedral Cluster Cores
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Dr. Viorel Cîrcu Dr. Yann Molard Dr. Maria Amela‐Cortes Ahmed Bentaleb Dr. Philippe Barois Dr. Vincent Dorcet Dr. Stéphane Cordier 《Angewandte Chemie (International ed. in English)》2015,54(37):10921-10925
New clustomesogens (i.e., metal atom clusters containing liquid crystalline (LC) materials) have been obtained by grafting neutral cyanobiphenyl (CB)‐ or cholesteryl‐containing tailor‐made dendritic mesomorphic triphenylphosphine oxide ligands on luminescent (M6Cli8)4+ octahedral cluster cores (M=Mo, W). The LC properties were studied by a combination of polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X‐ray powder diffraction analyses. While the organic ligands showed various mesophase types ranging from nematic, SmA columnar (SmACol), SmA, and SmC phases, it turned out that the corresponding clustomesogens formed layered phases (SmA) over a wide range of temperatures that depend on the nature and density of mesogenic groups employed. Intrinsic luminescence properties of the cluster precursors are preserved over the entire range of LC phase existence. 相似文献
25.
Enrique Alvarez-Manzaneda Rachid Chahboun Faouzia Bentaleb Esteban Alvarez M. Angeles Escobar Said Sad-Diki Maria José Cano Ibtissam Messouri 《Tetrahedron》2007,63(45):11204-11212
Two procedures to introduce an oxygenated function into the C-14 of abietane diterpenes with complete regioselectivity have been developed. Utilizing these, the synthesis of the antileishmanial quinone (−)-12-deoxyroyleanone (1) and a formal synthesis of antitumour and immunosuppressant (−)-triptonide (7) and (−)-triptolide (8) from (+)-abietic acid (13) have been carried out. 相似文献
26.
A. Nowak W. Urban W. Kurcewicz T. Rząca-Urban H. Mach B. Fogelberg J.L. Durell M.J. Leddy M.A. Jones W.R. Phillips A.G. Smith B.J. Varley M. Bentaleb E. Lubkiewicz N. Schulz I. Ahmad L.R. Morss 《The European Physical Journal A - Hadrons and Nuclei》1999,4(1):1-3
132Te was produced via the 232Th (α, fission) reaction at the Variable Energy Cyclotron , Calcutta. 132Te was separated in carrier-free form from the fission products by radiochemical separation and the half-lives for the 50
keV and 162 keV states of 132I were determined to be 2.94±0.11 ns and 0.55±0.04 ns respectively. The present results differ significantly from the previously
reported half-lives of 7.14 ns and 3.57 ns for the 50 keV and 162 keV states respectively.
Received: 28 July 1998 / Revised version: 23 September 1998 相似文献
27.
A. Korgul W. Urban T. Rząca-Urban M. Rejmund J.L. Durell M.J. Leddy M.A. Jones W.R. Phillips A.G. Smith B.J. Varley N. Schulz M. Bentaleb E. Lubkiewicz I. Ahmad L.R. Morss 《The European Physical Journal A - Hadrons and Nuclei》2000,7(2):167-176
Excited states in the neutron-rich, N=84 nuclei 134Sn, 136Te and 138Xe, populated in the spontaneous fission of 248Cm, were studied to medium spins using the EUROGAM2 array. OXBASH code calculations support the experimental identification
of maximum aligned configurations in these isotopes. Empirical shell model calculations agree with the proposed excitation
energy of the neutron h9/2 excitation in the 132Sn region. A discrepancy between the observed and calculated excitation energy of the Iπ= 12+ level in 136Te indicates possible admixtures of collective excitations in this nucleus. Clear signs of collective excitations are observed
in 138Xe.
Received: 10 November 1999 / Revised version: 22 December 1999 相似文献
28.
W. Urban N. Schulz M. Bentaleb E. Lubkiewicz J. L. Durell M. J. Leddy M. A. Jones W. R. Phillips A. G. Smith B. J. Varley I. Ahmad L. R. Morss 《The European Physical Journal A - Hadrons and Nuclei》2000,8(1):5-7
Excited levels in 141Xe, populated in spontaneous fission of 248Cm, were studied by means of prompt -ray spectroscopy, using the EUROGAMM2 array. Level scheme of 141Xe obtained in this work shows patterns characteristic of simplex symmetry with s=+i and s=-i bands present but low value of D0 moment indicates that octupole correlations in Xe isotopes are systematically lower than in Ba nuclei.
Received: 9 March 2000 / Accepted: 4 May 2000 相似文献
29.
Dr. Edivandro Girotto Marli Ferreira Dr. Parantap Sarkar Ahmed Bentaleb Dr. Elizabeth A. Hillard Prof. Hugo Gallardo Dr. Fabien Durola Dr. Harald Bock 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(20):7603-7610
Prolonged glyoxylation of pyrenyl‐1‐glyoxylic acid ethyl ester leads to a mixture of isomers with polar pyrenylene‐1,8‐diglyoxylic acid as the main product, whereas the centrosymmetric 1,6‐isomer is obtained in good yield from the corresponding dibromopyrene. Perkin condensations followed by Pd‐catalyzed cyclizations lead to isomeric dinaphthopyrene‐tetracarboxdiimides that self‐assemble into columnar liquid crystals of hexagonal and rectangular symmetry, of which the rectangular mesophases have unusually elongated unit cells. The cisoid diimides with both alkylimide substituents on the same side of the oblong arene system show a much greater tendency to self‐assemble into fluid stacks of disks than their centrosymmetric isomers. With racemically branched alkyl substituents, uniform vertical surface alignment of the columns in the high‐temperature hexagonal mesophase is resilient to cycling through the lower‐temperature rectangular and crystalline phases. 相似文献