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61.
The sensitivity of saturated aliphatic ketone stretching frequencies, vCO to structure and solvent effects is expressed by a four-term equationvco = 1740 + I(XXX) -0.24 G + 2.10?3G ·I(XXX)The four terms represent: the frequency of the base element (acetone) calculated in the absence of intermolecular interactions; the contribution of intramolecular environment E given by structure parameter I(itXXX) previously established in gas phase; that of the intermolecular environment related to the Allerhand and Schleyer G parameter; that of solvent-solute interactions. This equation covers an experimental range of 78 cm?1 for 192 measurements in four highly diverse solvents (C6H14, CC14, CH3CN, CHBr3) with a standard deviation of 1.6 cm?1; it expresses an overall statistical behavior, but masks individual behaviors. The latter are determined by comparing two characteristic parameters of ketones, a topological parameter I(XXX), and p expressing solvent sensitivity [slope of straight lines ν = f(G)]; they are Interpreted in terms of geometrical effect, variation of valency angles and of conformations. 相似文献
62.
Fort S Birikaki L Dubois MP Antoine T Samain E Driguez H 《Chemical communications (Cambridge, England)》2005,(20):2558-2560
Oligosaccharidic moieties of GM(2) and GM(3) gangliosides bearing an allyl or a propargyl aglycon, are efficiently biosynthesized on the gram scale by growing metabolically engineered Escherichia coli cells in the presence of the corresponding lactoside acceptors and sialic acid. 相似文献
63.
A general approach to information correction and fusion for belief functions is proposed, where not only may the information items be irrelevant, but sources may lie as well. We introduce a new correction scheme, which takes into account uncertain metaknowledge on the source’s relevance and truthfulness and that generalizes Shafer’s discounting operation. We then show how to reinterpret all connectives of Boolean logic in terms of source behavior assumptions with respect to relevance and truthfulness. We are led to generalize the unnormalized Dempster’s rule to all Boolean connectives, while taking into account the uncertainties pertaining to assumptions concerning the behavior of sources. Eventually, we further extend this approach to an even more general setting, where source behavior assumptions do not have to be restricted to relevance and truthfulness. We also establish the commutativity property between correction and fusion processes, when the behaviors of the sources are independent. 相似文献
64.
Maillard Christophe Maloubier Didier Boulay Olivier Savigny Victor Quemet Alexandre 《Journal of Radioanalytical and Nuclear Chemistry》2021,330(3):579-587
Journal of Radioanalytical and Nuclear Chemistry - Due to unexpected Pu behavior using the U/TEVA resin and the most-recognized reagents, some key separation stages need to be studied for the... 相似文献
65.
Didier Lesesvre Paul Pegon Filippo Santambrogio 《Set-Valued and Variational Analysis》2013,21(3):541-556
The main result of this paper is the existence of an optimal transport map T between two given measures μ and ν, for a cost which considers the maximal oscillation of T at scale δ, given by ω δ (T) :?=??sup|x???y|?<?δ |T(x)???T(y)|. The minimization of this criterion finds applications in the field of privacy-respectful data transmission. The existence proof unfortunately only works in dimension one and is based on some monotonicity considerations. 相似文献
66.
67.
Taratra André Fenoradosoa Céline Laroche Cedric Delattre Virginie Dulong Didier Le Cerf Luc Picton Philippe Michaud 《Applied biochemistry and biotechnology》2012,167(5):1303-1313
The rheological behavior of a sulfated galactan extracted from Halymenia durvillei, a red seaweed collected in the coastal waters of a small island of Madagascar (Nosy-be in Indian Ocean), was investigated in dilute and semi-dilute solutions. In dilute solution with NaCl at 0.3?M, the polysaccharide adopted a coil conformation whereas, at higher concentrations, the polymer had the behavior of shear-thinning fluid, typical of polymer with high molar mass or semi-rigid conformation. Degradations of this lambda carrageenan-like, using radical depolymerization, and high-pressure homogenization led to several samples of various and controlled molar masses. The measure of their intrinsic viscosities permitted the determination of the relationship of Mark?CHouwink?CSakurada. 相似文献
68.
Grignard condensation routes to 1,3‐disilacyclobutane‐containing cyclolinear polycarbosilanes
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Xinxing Liu Jitendra S. Rathore Geraud Dubois Leonard V. Interrante 《Journal of polymer science. Part A, Polymer chemistry》2017,55(9):1547-1557
Alkylene‐ and arylene‐bridged cyclolinear polycarbosilanes (CLPCS) with 1,3‐disilacyclobutane (DSCB) rings incorporated in the main chain of the polymer were prepared by polycondensation between corresponding di‐functional DSCB derivatives and di‐Grignard reagents. Well‐defined, low molecular weight (Mn = 3–5K; DP = 17–26), hexylene‐ and phenylene‐bridged CLPCS polymers were obtained without appreciable ring opening of the DSCB rings. Large exothermic peaks were observed in the DSC for these CLPCSs, which indicated, along with the IR spectra, that crosslinking occurred on heating to about 250 °C via the ring opening of the embedded, alternating, DSCB rings. Moreover, PB‐CLPCS undergoes photochemically induced crosslinking on UV irradiation to form crosslinked polycarbosilane network films. The spin‐cast, cured, films of these CLPCSs exhibit relatively low dielectric constants and promising thermal and mechanical properties for applications in electronics, for example, directly UV‐photoimprinted low‐k dielectrics. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1547–1557 相似文献
69.
Xanthates were easily prepared by adsorption of alcohol on KF-Al2O3 followed by treatment of carbon disulfide and iodomethane at room temperature. Pyrolysis of benzyl xanthate affords to a complex mixture of products. A radical process was proposed to explain the nature of products obtained. 相似文献
70.
Hang Yin Qian Cheng Roselyne Rosas Prof. Stéphane Viel Dr. Valérie Monnier Prof. Laurence Charles Prof. Didier Siri Dr. Didier Gigmes Dr. Olivier Ouari Prof. Ruibing Wang Dr. Anthony Kermagoret Dr. David Bardelang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(54):12552-12559
A viologen derivative carrying a benzimidazole group ( V-P-I 2+; viologen–phenylene–imidazole V-P-I ) can be dimerized in water using cucurbit[8]uril (CB[8]) in the form of a 2:2 complex resulting in a negative shift of the guest pKa, by more than 1 pH unit, contrasting with the positive pKa shift usually observed for CB-based complexes. Whereas 2:2 complex protonation is unclear by NMR, silver cations have been used for probing the accessibility of the imidazole groups of the 2:2 complexes. The protonation capacity of the buried imidazole groups is reduced, suggesting that CB[8] could trigger proton release upon 2:2 complex formation. The addition of CB[8] to a solution containing V-P- I 3+ indeed released protons as monitored by pH-metry and visualized by a coloured indicator. This property was used to induce a host/guest swapping, accompanied by a proton transfer, between V-P-I 3+ ⋅ CB[7] and a CB[8] complex of 1-methyl-4-(4-pyridyl)pyridinium. The origin of this negative pKa shift is proposed to stand in an ideal charge state, and in the position of the two pH-responsive fragments inside the two CB[8] which, alike residues engulfed in proteins, favour the deprotonated form of the guest molecules. Such proton release triggered by a recognition event is reminiscent of several biological processes and may open new avenues toward bioinspired enzyme mimics catalyzing proton transfer or chemical reactions. 相似文献