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排序方式: 共有159条查询结果,搜索用时 62 毫秒
101.
JT Lowe MD Lee LB Akella E Davoine EJ Donckele L Durak JR Duvall B Gerard EB Holson A Joliton S Kesavan BC Lemercier H Liu JC Marié CA Mulrooney G Muncipinto M Welzel-O'Shea LM Panko A Rowley BC Suh M Thomas FF Wagner J Wei MA Foley LA Marcaurelle 《The Journal of organic chemistry》2012,77(17):7187-7211
The synthesis and diversification of a densely functionalized azetidine ring system to gain access to a wide variety of fused, bridged, and spirocyclic ring systems is described. The in vitro physicochemical and pharmacokinetic properties of representative library members are measured in order to evaluate the use of these scaffolds for the generation of lead-like molecules to be used in targeting the central nervous system. The solid-phase synthesis of a 1976-membered library of spirocyclic azetidines is also described. 相似文献
102.
P Ransom TA Arnold AL Thompson JC Buffet D O'Hare 《Dalton transactions (Cambridge, England : 2003)》2012,41(37):11267-11269
Synthesis, magnetic properties, NMR spectroscopy, and crystallographic details of an ethylene bridged hexamethylindenyl (EBI*) cerium iodide complex [(EBI*)CeI(THF)] are reported. 相似文献
103.
Carbon storage in saline formations is considered as a promising option to ensure the necessary decrease of CO2 anthropogenic emissions. Its industrial development in those formations is above all conditioned by its safety demonstration.
Assessing the evolution of trapped and mobile CO2 across time is essential in the perspective of reducing leakage risks. In this work, we focus on residual trapping phenomenon
occurring during the wetting of the injected CO2 plume. History dependent effects are of first importance when dealing with capillary trapping. We then apply the classical
fractional flow theory (Buckley–Leverett type model) and include trapping and hysteresis models; we derive an analytical solution
for the temporal evolution of saturation profile and of CO2 trapped quantity when injecting water after the gas injection (“artificial imbibition”). The comparison to numerical simulations
for different configurations shows satisfactory match and justifies, in the case of industrial CO2 storage, the assumptions of incompressible flow with no consideration of capillary pressure. The obtained analytical solution
allows the quick assessment of both the quantity and the location of mobile gas left during imbibition. 相似文献
104.
Fleutot S Dupin JC Renaudin G Martinez H 《Physical chemistry chemical physics : PCCP》2011,13(39):17564-17578
We report an original strategy to describe, via X-ray photoelectron spectroscopy (XPS) measurements, the interactions between the organic and the mineral sub-systems within a multifunctional hybrid material. A tunable layered double hydroxide (LDH) host system, either a Zn(2)Al- or Cu(2)Cr-hydrotalcite like compound, is modified with the insertion of the organic guest entities, 4-phenol-sulfonate (HBS) or -carboxylate (HBC). The resulting interactions are studied at two levels: after the organic molecules' insertion in the host LDH (ionic exchange between the LDH counter-ions and the organic anions) and after the condensation (grafting) of the organic species onto the mineral layers when thermally treated. For the inserted material, the main XPS results show a stabilization of the organic molecules within the mineral sheets via H bonding as found elsewhere with FTIR study, the mineral matrix being unchanged. The XPS signal of the organic molecules slightly changes with a widening of core peaks, attesting to some local surrounding modifications. When heating up the Zn(2)Al hybrid material, stronger interactions between organic and inorganic systems appeared from around 80 °C with some obvious electronic changes as monitored with the XPS S2p signal of the HBS guest molecules. At the same time, the PXRD pattern clearly shows a decrease of the basal spacing according to a two step contraction process which could be interpreted as a progressive organic molecule condensation onto the inorganic layers via iono-covalent bonds. A copper-chromium LDH is also studied to probe the same kind of interactions with the HBS molecules. The ability of distortion of such mineral material involves a peculiar process of contraction from 40 °C with the immediate and effective anchorage of organic molecules. 相似文献
105.
Alfonsina E. Andreatta Rafael Lugo Jean-Charles de Hemptinne Esteban A. Brignole Susana B. Bottini 《Fluid Phase Equilibria》2010
In this work, a group-contribution equation of state that takes into account association effects (GCA-EoS) is extended to model the phase behavior of fatty esters (biodiesel) in binary mixtures with glycerol, alcohols and water and ternary mixtures with glycerol and methanol. A new associating group (glycerol hydroxyl group: OHGly) was defined to take into consideration the association effects in the glycerol molecule. Self-association of methanol, water and glycerol and cross-association between methanol–glycerol, alcohol–ester, water–ester and glycerol–ester groups were considered. New pure-group, binary interaction and association parameters have been determined. The correlations and predictions of the model are found in acceptable agreement with selected experimental data reported in the literature. 相似文献
106.
Dongdai Lin Jean-Charles Faugère Ludovic Perret Tianze Wang 《Finite Fields and Their Applications》2012,18(2):283-302
The Isomorphism of Polynomials (IP) is one of the most fundamental problems in multivariate public key cryptography (MPKC). In this paper, we introduce a new framework to study the counting problem associated to IP. Namely, we present tools of finite geometry allowing to investigate the counting problem associated to IP. Precisely, we focus on enumerating or estimating the number of isomorphism equivalence classes of homogeneous quadratic polynomial systems. These problems are equivalent to finding the scale of the key space of a multivariate cryptosystem and the total number of different multivariate cryptographic schemes respectively, which might impact the security and the potential capability of MPKC. We also consider their applications in the analysis of a specific multivariate public key cryptosystem. Our results not only answer how many cryptographic schemes can be derived from monomials and how big the key space is for a fixed scheme, but also show that quite many HFE cryptosystems are equivalent to a Matsumoto–Imai scheme. 相似文献
107.
Richard Ferrière Jean-Pierre Goedgebuer Jean-Charles Viénot 《Optics Communications》1979,31(3):285-289
This paper describes a recording and reconstruction method applied to two-dimension Fourier holography, in which the illumination at the recording stage is spatially coherent and temporally incoherent. The various chromatic components of the information to be recorded in the hologram are spread along a direction orthogonal to the entrance slit of a spectroscope that behaves as scanning pupil performing a chromatic coding. The message, both spatially and temporally coded, can be reconstructed by using a conventional process, the light source being still polychromatic. 相似文献
108.
Max Robba Daniel Maume Jean-Charles Lancelot 《Journal of heterocyclic chemistry》1978,15(7):1209-1213
Electrophilic substitution reactions of the 1- and 4-triazino-indolones were made on lactamic nitrogen with methyl sulphate or benzyl chloride and on the homocycle with bromine or nitric acid. BrominatJon and nitration reactions gave either mono-substitutions on position 10 or disubstitutions on position 7 and 10 or 9 and 10 or polysubstitutions leading to mixtures of tri-and tetrasubstituted compounds. The structure of the derivatives was determined by nmr, study of the NOE effect and unequivocal synthesis. 相似文献
109.
Jeremy Jeudy Arnaud Salvador Romain Simon Aurore Jaffuel Catherine Fonbonne Jean-François Léonard Jean-Charles Gautier Olivier Pasquier Jerome Lemoine 《Analytical and bioanalytical chemistry》2014,406(4):1193-1200
Targeted mass spectrometry in the so-called multiple reaction monitoring mode (MRM) is certainly a promising way for the precise, accurate, and multiplexed measurement of proteins and their genetic or posttranslationally modified isoforms. MRM carried out on a low-resolution triple quadrupole instrument faces a lack of specificity when addressing the quantification of weakly concentrated proteins. In this case, extensive sample fractionation or immunoenrichment alleviates signal contamination by interferences, but in turn decreases assay performance and throughput. Recently, MRM3 was introduced as an alternative to MRM to improve the limit of quantification of weakly concentrated protein biomarkers. In the present work, we compare MRM and MRM3 modes for the detection of biomarkers in plasma and urine. Calibration curves drawn with MRM and MRM3 showed a similar range of linearity (R 2?>?0.99 for both methods) with protein concentrations above 1 μg/mL in plasma and a few nanogram per milliliter in urine. In contrast, optimized MRM3 methods improve the limits of quantification by a factor of 2 to 4 depending on the targeted peptide. This gain arises from the additional MS3 fragmentation step, which significantly removes or decreases interfering signals within the targeted transition channels. 相似文献
110.
We present an analytical model for a Roberts Linkage used as an ultra low frequency vibration isolator. The Roberts Linkage is a structure that simulates a very long radius conical pendulum, at a relatively small height. We show through an analytical solution that it is possible to independently tune the centre of percussion and the resonant frequency for arbitrary geometrical configurations. The result is shown to provide a practical tuning solution, which achieves near ideal vibration isolation. 相似文献