排序方式: 共有36条查询结果,搜索用时 15 毫秒
1.
Dr. Joffrey Pijeat Léo Chaussy Roxanne Simoës Dr. Jacopo Isopi Prof. Dr. Jean-Sébastien Lauret Prof. Dr. Francesco Paolucci Prof. Dr. Massimo Marcaccio Dr. Stéphane Campidelli 《ChemistryOpen》2021,10(10):997-1003
The synthesis of π-extended porphyrins containing anthracenyl moieties still represents an important challenge. Here, we report on the synthesis of a series of unsubstituted naphthyl-, pyrenyl- and anthracenyl-fused zinc porphyrin derivatives. To this aim, meso-substitued porphyrins are synthesized and the fusion of the PAHs (Polycyclic Aromatic Hydrocarbon) on the β-positions are performed through thermally induced dehydro-aromatization. The fused zinc-porphyrin derivatives are fully characterized and their optical absorption and photoluminescence properties are reported. We also demonstrate that zinc can be removed from the porphyrin core, giving rise to pure C, H, N materials. This work constitutes the first step towards the synthesis of the fully-fused tetra-anthracenylporphyrin. 相似文献
2.
Pirnia Pouyan Duhaime François Ethier Yannic Dubé Jean-Sébastien 《Transport in Porous Media》2019,129(3):837-853
Transport in Porous Media - Several methods are employed for drag force calculations with the discrete element method depending on the desired accuracy and the number of particles involved. For... 相似文献
3.
Zirconium amide-iodide complexes were synthesized for possible use as chemical vapor deposition precursors to zirconium nitride films. The series of six complexes Zr(NR(2))(4-n)I(n)(R = Me or Et; n = 1-3) was prepared by reacting ZrI(4) and Zr(NR(2))(4) in hot toluene. X-ray crystallographic analyses were performed for Zr(NMe(2))(3)I, Zr(NEt(2))(2)I(2), and Zr(NEt(2))I(3). In the solid state, Zr(NMe(2))(3)I and Zr(NEt(2))(2)I(2) are the discrete dimers [Zr(NMe(2))(2)I(mu-NMe(2))](2) and [Zr(NEt(2))(2)I(mu-I)](2), and Zr(NEt(2))I(3) is the polymer of dimers ([Zr(NEt(2))I(2)(mu-I)](2))(n). In solution, Zr(NEt(2))(3)I is proposed to be monomeric on the basis of NMR data and a molecular weight determination. The complex Zr(NEt(2))(3)I is the most promising precursor candidate because of its physical properties. 相似文献
4.
We present a quantum theory of frustrated diamond lattice antiferromagnets. Considering quantum fluctuations as the predominant mechanism relieving spin frustration, we find a rich phase diagram comprising of six phases with coplanar spiral ordering in addition to the Néel phase. By computing the specific heat of these ordered phases, we obtain a remarkable agreement between (k, k, 0) spiral ordering and the experimental specific heat data for the diamond lattice spinel compounds MnSc2S4, Co3O4, and CoRh2O4, i.e., specific heat data is a strong evidence for (k, k, 0) spiral ordering in all of these materials. This prediction can be tested in future neutron scattering experiments on Co3O4 and CoRh2O4, and is consistent with existing neutron scattering data on MnSc2S4. Based on this agreement, we infer a monotonically increasing relationship between frustration and the strength of quantum fluctuations. 相似文献
5.
Jean-Sébastien Tancrez Philippe Chevalier Pierre Semal 《Annals of Operations Research》2011,182(1):163-191
The analysis of manufacturing systems with finite capacity and with general service time distributions is made of two steps:
the distributions have first to be transformed into tractable phase-type distributions, and then the modified system can be
analytically modelled. In this paper, we propose a new alternative in order to build tractable phase-type distributions, and
study its effects on the global modelling process. Called “probability masses fitting” (PMF), the approach is quite simple:
the probability masses on regular intervals are computed and aggregated on a single value in the corresponding interval, leading
to a discrete distribution. PMF shows some interesting properties: it is bounding, monotonic, refinable, it approximates distributions
with finite support and it conserves the shape of the distribution. With the resulting discrete distributions, the evolution
of the system is then exactly modelled by a Markov chain. Here, we focus on flow lines and show that the method allows us
to compute upper and lower bounds on the throughput as well as good approximations of the cycle time distributions. Finally,
the global modelling method is shown, by numerical experiments, to compute accurate estimations of the throughput and of various
performance measures, reaching accuracy levels of a few tenths of a percent. 相似文献
6.
Jean-Sébastien Coron 《Designs, Codes and Cryptography》2009,50(1):115-133
The first practical identity based encryption (IBE) scheme was published by Boneh and Franklin at Crypto 2001, based on the
elliptic curve pairing. Since that time, many other IBE schemes have been published. In this paper, we describe a variant
of Boneh-Franklin with a tight reduction in the random oracle model. Our new scheme is quite efficient compared to existing
schemes; moreover, upgrading from Boneh-Franklin to our new scheme is straightforward.
相似文献
7.
We determine the spin-exchange dynamical structure factor of the Heisenberg spin chain, as is measured by indirect resonant inelastic x-ray scattering (RIXS). We find that two-spin RIXS excitations nearly entirely fractionalize into two-spinon states. These share the same continuum lower bound as single-spin neutron scattering excitations, even if the relevant final states belong to orthogonal symmetry sectors. The RIXS spectral weight is mainly carried by higher-energy excitations, and is beyond the reach of the low-energy effective theories of Luttinger liquid type. 相似文献
8.
We compute the momentum- and frequency-dependent longitudinal spin structure factor for the spin-1/2 XXZ Heisenberg spin chain in a magnetic field, using exact determinant representations for form factors on the lattice. Multiparticle (i.e., multispinon) contributions are computed numerically throughout the Brillouin zone, yielding saturation of the sum rule to high precision. 相似文献
9.
Fournier Nicolas Giet Jean-Sébastien 《Methodology and Computing in Applied Probability》2004,6(2):219-231
The Smoluchowski coagulation equation describes the concentration c(t,x) of particles of mass x [ 0,] at the instant t 0, in an infinite system of coalescing particles. It is well-known that in some cases, gelation occurs: a particle with infinite mass appears. But this infinite particle is inert, in the sense that it does not interact with finite particles. We consider the so-called Marcus–Lushnikov process, which is a stochastic finite system of coalescing particles. This process is expected to converge, as the number of particles tends to infinity, to a solution of the Smoluchowski coagulation equation. We show that it actually converges, for t [0,], to a modified Smoluchowski equation, which takes into account a possible interaction between finite and infinite particles. 相似文献
10.
Jeffrey M. Wheeler Christoph Kirchlechner Jean-Sébastien Micha Johann Michler Daniel Kiener 《哲学杂志》2016,96(32-34):3379-3395
As the length scale of sample dimensions is reduced to the micron and sub-micron scales, the strength of various materials has been observed to increase with decreasing size, a fact commonly referred to as the ‘sample size effect’. In this work, the influence of temperature on the sample size effect in copper is investigated using in situ microcompression testing at 25, 200 and 400 °C in the SEM on vacuum-annealed copper structures, and the resulting deformed structures were analysed using X-ray μLaue diffraction and scanning electron microscopy. For pillars with sizes between 0.4 and 4 μm, the size effect was measured to be constant with temperature, within the measurement precision, up to half of the melting point of copper. It is expected that the size effect will remain constant with temperature until diffusion-controlled dislocation motion becomes significant at higher temperatures and/or lower strain rates. Furthermore, the annealing treatment of the copper micropillars produced structures which yielded at stresses three times greater than their un-annealed, FIB-machined counterparts. 相似文献