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991.
Alain Quilliot 《Discrete Applied Mathematics》2008,156(17):3267-3275
We present a theoretical framework, which is based upon notions of ordered hypergraphs and antichain polyhedra, and which is dedicated to the combinatorial analysis of preemptive scheduling problems submitted to parallelization constraints.This framework allows us to characterize specific partially ordered structures which are such that induced preemptive scheduling problems may be solved through linear programming. To prove that, in the general case, optimal preemptive schedules may be searched inside some connected subset of the vertex set of an Antichain Polyhedron. 相似文献
992.
The aim of this paper is to present a procedure of construction of constitutive equations within the framework of Continuum
Mechanics. The main focus of our effort is to introduce the geometric change at a high level of strain and the damage which
are generally developed in simple tests (tension, shear) of polymeric materials such as polypropylene compounds or copolymers
(PP). High-resolution strain-mapping techniques are employed to determine the surface strain fields and, consequently, a measurement
of the volume change. A phenomenological model based upon experimental observations was developed to reproduce the main behavior,
e.g., the stress strain curves, including the volume change and their consequences. State Variables are defined and related
to their evolution in relation with the state laws. The identification of the resulting model was made by reproducing the
data issued from basic tests (Tension, Iosipescu Shear).
Published in Russian in Vysokomolekulyarnye Soedineniya, Ser. A. 2008, Vol. 50, No. 5, pp. 850–861.
This article was submitted by the authors in English. 相似文献
993.
Masamichi Tsuboi Yoshiaki Hamada Lucien Henry Jean Chazelas Alain Valentin 《Journal of Molecular Spectroscopy》1984,108(2):328-342
The infrared absorption spectrum of NH2NH2 vapor has been observed in the region 899–1077 cm?1, where the antisymmetric wagging band (va = 1 ← 0) appears, by the use of a Fourier transform spectrometer with a practical resolution of 0.003 cm?1. In the region 925.0–925.6 cm?1, the spectrum was also observed with a tunable diode laser, and a component, β, of the pQ2 cluster has been further resolved. Most of the absorption lines assignable to β-pP2(J″), γ-pP2(J″), β-pQ2(J″), γ-rQ0(J″), β-rR0(J″), and γ-rR0(J″), where J″ = 2 ~ 15, have been identified. From these observed transition frequencies, in combination with the ground state energy levels given by microwave spectroscopy, the energy level structure of the K′ = 1 rotational states was determined. From this, the following molecular parameters for the va = 1 state were determined: molecular asymmetry, B′-C″ = 0.00017 cm?1; a parameter q5 describing an umbrella motion Coriolis interaction (q5K) about the a axis, q5 = ?0.0030 cm?1; its J(J + 1) variation, q5j = 0.00014 cm?1; and a parameter describing an umbrella-motion K-type doubling g5J(J + 1), g5 = 0.000021 cm?1. 相似文献
994.
Alain Deronzier 《Tetrahedron letters》1984,25(27):2867-2868
The reduction of tropylium cation (Tr+) with the concomitant oxidation of O,O′-dialkyldithiophosphate anions (dtp?) have been achieved by visible irradiation of their acetonitrile solution in presence of a bipyridinium dication ; the later via its charge transfer complex with dtp? acts as a light-harvest and as an electron relay. 相似文献
995.
996.
A stochastic variational inequality is proposed to model a white noise excited elasto-plastic oscillator. The solution of
this inequality is essentially a continuous diffusion process for which a governing diffusion equation is obtained to study
the evolution in time of its probability distribution. The diffusion equation is degenerate, but using the fact that the degeneracy
occurs on a bounded region we are able to show the existence of a unique solution satisfying the desired properties. We prove
the ergodic properties of the process and characterize the invariant measure. Our approach relies on extending Khasminskii’s
method (Stochastic Stability of Differential Equations, Sijthoff and Noordhoff, 1980), which in the present context leads to the study of degenerate Dirichlet problems with nonlocal boundary conditions.
This research was partially supported by a grant from CEA, Commissariat à l’énergie atomique and by the National Science Foundation
under grant DMS-0705247. 相似文献
997.
Yves Langlois Alain Petit Pauline Rémy Marie-Christine Scherrmann Cyrille Kouklovsky 《Tetrahedron letters》2008,49(39):5576-5579
Camphor-derived sulfonylhydrazines proved to be very active for organocatalyzed Diels-Alder cycloadditions with cyclopentadiene. Good chemical yields and enantiomeric excesses up to 89% and 88% are obtained for endo/exo adducts. 相似文献
998.
Andrew Taylor Robert L. Jones Alain Leblanc Olav Mazarrasa Mi-Young Lee Patrick J. Parsons Marina Patriarca Jean-Philippe Weber Cas Weykamp 《Accreditation and quality assurance》2009,14(8-9):461-466
An under-recovery of inorganic mercury added to urine and a wide range of results is observed in quality assessment schemes (EQAS) for trace elements. Furthermore, the under-recoveries are inconsistent suggesting features associated with the urine matrix may make the mercury unavailable for measurement. To investigate the instability of mercury in urine the following experiments were set up: (1) a sample of Hg2+ in water with various ‘stabilizers’ added was sent to UK external quality assessment scheme participants. (2) Urine was collected from volunteers who also completed a 3-day food diary. Hg, Ca, Mg, Se, uric acid, phosphate, creatinine, reducing substances and protein were measured. Inorganic mercury was spiked into the urine, stabilizers were added and the mercury determined following storage. The results confirmed under-recovery of mercury in association with the urine matrix. Further investigations of how urinary components affect the measurement of mercury are necessary. 相似文献
999.
Alain Hercouet 《Tetrahedron letters》2004,45(47):8749-8751
Ruthenium catalyzed ring-closing metathesis has been used as a key step for the synthesis of cyclic α-aminoboronic esters as, for example, boron-containing mimics of pipecolic, 2-azepanecarboxylic acid or baikiain. 相似文献
1000.
Bachir Bentria Djamal Benbertal Zoulikha Hebboul Muriel Bagieu‐Beucher Alain Mosset 《无机化学与普通化学杂志》2005,631(5):894-901
The investigation of CdCl2‐HIO3 system, in aqueous and HNO3 solutions, revealed that anhydrous cadmium iodate presents a marked polymorphism. No less than four new Cd(IO3)2polymorphs have been isolated and characterized, two of which showing second harmonic generation activity. Single crystals of ε‐Cd(IO3)2 are obtained by slowly evaporating, at 60 °C, a saturated solution of γ‐Cd(IO3)2 in 30 % nitric acid. This compound crystallizes in the orthorhombic space group Pca21 [a = 17.581(2), b = 5.495(2), c = 11.163(2) Å]. The basic structural unit can be described as the connection of two cadmium polyhedrons with a short metal – metal distance of 3.88Å. These units are further linked through two other iodate bridges resulting in layers parallel to the (100) plane. The 3D linkage is ensured by short bonds of the fourth iodate group. 相似文献