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51.
Cristelle Portet Dmitry Kazachkin Sebastian Osswald Yury Gogotsi Eric Borguet 《Thermochimica Acta》2010,497(1-2):137-142
Carbide-derived carbons produced by chlorination of titanium carbide at 600, 800, or 1100 °C were subjected to a post-treatment at 600 °C in Ar, H2, or NH3 atmosphere. Experimental results suggest that the chlorination temperature influences the ordering of carbon in a manner that impacts specific surface area and porosity. Higher chlorination temperatures lead to higher total pore volume and increased ordering, but lower microporosity. The effect of post-treatments on surface chemistry is pronounced only for samples chlorinated at 600 °C; post-treatments in Ar are shown to be less effective for chlorine removal than those performed in H2 or NH3. Post-treatments in Ar result in a lower total pore volume compared to the ones in H2 or NH3 for the same chlorination temperature. Samples chlorinated at higher temperatures contained less oxygen functionalities than samples chlorinated at 600 °C, and showed correspondingly less desorption of H2O, possibly due to diminished uptake of ambient water. 相似文献
52.
Vincent Larraillet Aleksey Vorobyev Claire Brunet Jér?me Lemoine Yury O. Tsybin Rodolphe Antoine Philippe Dugourd 《Journal of the American Society for Mass Spectrometry》2010,21(4):670-680
We compare product-ion mass spectra produced by electron detachment dissociation (EDD) and electron photodetachment dissociation
(EPD) of multi-deprotonated peptides on a Fourier transform and a linear ion trap mass spectrometer, respectively. Both methods,
EDD and EPD, involve the electron emission-induced formation of a radical oxidized species from a multi-deprotonated precursor
peptide. Product-ion mass spectra display mainly fragment ions resulting from backbone cleavages of Cα-C bond ruptures yielding a and x ions. Fragment ions originating from N-Cα backbone bond cleavages are also observed, in particular by EPD. Although EDD and EPD methods involve the generation of a
charge-reduced radical anion intermediate by electron emission, the product ion abundance distributions are drastically different.
Both processes seem to be triggered by the location and the recombination of radicals (both neutral and cation radicals).
Therefore, EPD product ions are predominantly formed near tryptophan and histidine residues, whereas in EDD the negative charge
solvation sites on the backbone seem to be the most favorable for the nearby bond dissociation. 相似文献
53.
54.
Ying-Fei Zhang Zhi-Hui Kang Yun Jiang Yury M. Andreev Konstantin A. Kokh Anna V. Shaiduko 《Optics Communications》2011,284(6):1677-1681
We report a systematic study of AgGaS2- and Al-doped GaSe crystals in comparison with pure GaSe and S-doped GaSe crystals. AgGaS2-doped GaSe (GaSe:AgGaS2) crystal was grown by Bridgman technique from the melt of GaSe:AgGaS2 (10.6 wt.%). Its real composition was identified as GaSe:S (2 wt.%). Al-doped GaSe (GaSe:Al) crystals were grown from the melt of GaSe and 0.01, 0.05, 0.1, 0.5, 1, 2 mass % of aluminium. Al content in the grown crystals is too small to be measured. The hardness of GaSe:S (2 wt.%) crystal grown from the melt of GaSe:AgGaS2 is 25% higher than that of GaSe:S (2 wt.%) crystal grown by a conventional S-doping technique and 1.5- to 1.9-times higher than that of pure GaSe. GaSe:Al crystals are characterized by 2.5- to 3-times higher hardness than that of pure GaSe and by extremely low conductivity of ≤ 10− 7 Om− 1 cm− 1. A comparative experiment on SHG in AgGaS2-, Al-, S-doped GaSe and pure GaSe is carried out under the pumps of 2.12-2.9 μm fs OPA and 9.2−10.8 μm ns CO2 laser. It was found that GaSe:S crystals possess the best physical properties for mid-IR applications among these doped GaSe crystals. GaSe:Al crystals have relatively low conductivity which have strong potential for THz application. 相似文献
55.
In the (r∣p)-centroid problem, two players, called leader and follower, open facilities to service clients. We assume that clients are identified with their location on the Euclidean plane, and facilities can be opened anywhere in the plane. The leader opens p facilities. Later on, the follower opens r facilities. Each client patronizes the closest facility. In case of ties, the leader’s facility is preferred. The goal is to find p facilities for the leader to maximize his market share. We show that this Stackelberg game is \(\varSigma_{2}^{P}\) -hard. Moreover, we strengthen the previous results for the discrete case and networks. We show that the game is \(\varSigma_{2}^{P}\) -hard even for planar graphs for which the weights of the edges are Euclidean distances between vertices. 相似文献
56.
57.
Yury Yu. Rusakov Leonid B. Krivdin Stephan P. A. Sauer Ekaterina P. Levanova Galina G. Levkovskaya 《Magnetic resonance in chemistry : MRC》2010,48(1):44-52
Experimental measurements and second‐order polarization propagator approach (SOPPA) calculations of 77Se? 1H spin–spin coupling constants together with theoretical energy‐based conformational analysis in the series of 2‐substituted selenophenes have been carried out. A new basis set optimized for the calculation of 77Se? 1H spin–spin coupling constants has been introduced by extending the aug‐cc‐pVTZ‐J basis for selenium. Most of the spin–spin coupling constants under study, especially vicinal 77Se? 1H couplings, demonstrated a remarkable stereochemical behavior with respect to the internal rotation of the substituent in the 2‐position of the selenophene ring, which is of major importance in the stereochemical studies of the related organoselenium compounds. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
58.
A multicriteria Boolean programming problem with linear cost functions in which initial coefficients of the cost functions are subject to perturbations is considered. For any optimal alternative, with respect to parameterized principle of optimality “from Condorcet to Pareto”, appropriate measures of the quality are introduced. These measures correspond to the so-called stability and accuracy functions defined earlier for optimal solutions of a generic multicriteria combinatorial optimization problem with Pareto and lexicographic optimality principles. Various properties of such functions are studied and maximum norms of perturbations for which an optimal alternative preserves its optimality are calculated. To illustrate the way how the stability and accuracy functions can be used as efficient tools for post-optimal analysis, an application from the voting theory is considered. 相似文献
59.
Yury Grabovsky Vladislav A. Kucher Lev Truskinovsky 《Continuum Mechanics and Thermodynamics》2011,23(2):87-123
In the case of Lipschitz extremals of vectorial variational problems, an important class of strong variations originates from
smooth deformations of the corresponding non-smooth graphs. These seemingly singular variations, which can be viewed as combinations
of weak inner and outer variations, produce directions of differentiability of the functional and lead to singularity-centered
necessary conditions on strong local minima: an equality, arising from stationarity, and an inequality, implying configurational
stability of the singularity set. To illustrate the underlying coupling between inner and outer variations, we study in detail
the case of smooth surfaces of gradient discontinuity representing, for instance, martensitic phase boundaries in non-linear
elasticity. 相似文献
60.
Adrian P Higson Yury E Tsvetkov Michael A.J Ferguson Andrei V Nikolaev 《Tetrahedron letters》1999,40(52):297-9284
The triglycosyl monophosphate 1, heptaglycosyl triphosphates 2 and 3, and octaglycosyl triphosphate 4, which are fragments of the phosphoglycan part of Leishmania major lipo- and proteo-phosphoglycans have been prepared using di- and tri-saccharide H-phosphonates for construction of the phosphodiester bridges. 相似文献