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101.
Gergely B. Rédey A. Guimon C. Gervasini A. Auroux A. 《Journal of Thermal Analysis and Calorimetry》1999,56(3):1233-1241
The surface properties of gallium oxide and tin dioxide supported on alumina or titania have been studied by adsorption microcalorimetry.
The differential heats of adsorption of various pollutant adsorbates such as sulfur dioxide, nitrogen monoxide, nitrogen dioxide
and also ammonia were measured on these catalytic surfaces. NH3, SO2, NO2 are strongly adsorbed while NO is only physisorbed. The supported Ga2O3 samples show a slight decrease in acidity as probed by ammonia adsorption, compared to alumina or titania. The addition of
SnO2 decreases the number of strong acid sites but creates a few weak and medium strength acid sites on alumina and does not modify
the acidity of titania. In all cases, the basicity, probed by SO2 adsorption, is very strongly affected by the deposition of Ga2O3 or SnO2. The differential heats of NO2 adsorption remain nearly constant on all samples. The heats of adsorption are discussed as a function of the coverage and
of the amount of guest oxide.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
102.
Saara Riuttamäki Gergely Laczkó Dr. Ádám Madarász Dr. Tamás Földes Dr. Imre Pápai Anton Bannykh Prof. Dr. Petri M. Pihko 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(45):e202201030
We demonstrate herein the capacity of simple carboxylate salts – tetrametylammonium and tetramethylguanidinium pivalate – to act as catalysts in the isomerization of β,γ-unsaturated thioesters to α,β-unsaturated thioesters. The carboxylate catalysts gave reaction rates comparable to those obtained with DBU, but with fewer side reactions. The reaction exhibits a normal secondary kinetic isotope effect (k1H/k1D=1.065±0.026) with a β,γ-deuterated substrate. Computational analysis of the mechanism provides a similar value (k1H/k1D=1.05) with a mechanism where γ-reprotonation of the enolate intermediate is rate determining. 相似文献
103.
We have investigated characteristics of the local symmetry, such as cosine distribution of bond angles and second-order invariants of spherical harmonics for simple disordered systems with systematically varied radial distributions. Two types of variation were used at three different packing fraction values. None of the perturbations affected the basic features, but the extent of local order changed considerably. The most significant alterations were found for the case with the lowest packing fraction. The results presented in this paper may be used as guidelines for assessing the quality of agreement between radial distribution functions from different sources, such as that of simulations and diffraction experiments. 相似文献
104.
Three different fluorescent tags have been compared for the quantitative analysis of aspartate and glutamate in brain microdialysate samples. Separation conditions have been optimized to achieve short analysis time using reversed polarity separation in coated capillary. Method validation has revealed similar quantification limit of 0.1?μM of analytes using either of the labels, although LOD values were different: 7.8-9.8?nM for 4-fluoro-7-nitro-2,1,3-benzoxadiazole, 3.5?nM for fluorescein-5-isothiocyanate and 1.3-1.5?nM for carboxyfluorescein succinimidyl ester derivatives. The almost two orders of magnitude difference between LOD and LOQ values is likely due to the unreliable derivatization reaction at low sample concentration. Based on the superior stability, FITC derivatization was used for the analysis of biological samples. The applicability of the method has been demonstrated by analyzing basal and potassium evoked amino acid concentrations in individual brain microdialysate samples. 相似文献
105.
Tamás Csay Gergely Rácz Erzsébet Takács László Wojnárovits 《Radiation Physics and Chemistry》2012,81(9):1489-1494
The γ-radiolytic degradation of chloramphenicol (CPL) was investigated in 0.1–1 mmol dm?3 aqueous solutions at various radiation conditions. The destruction of CPL was monitored by UV–vis spectrophotometric method through the decrease in the intensity of the absorbance band at 276 nm. LC-MS/MS was used to identify the degradation products. Results indicate that ?OH can add onto the CPL aromatic ring or can abstract H-atom from the side chain. The reductive dechlorination of CPL was also studied based on the reaction of eaq? with CPL. In 0.1 mmol dm?3 solution above 2.5 kGy dose complete CPL degradation was achieved. In the presence of dissolved oxygen at relatively low dose, various oxidation products were observed. In the presence of tertiary butanol radical scavenger tertiary butanol group containing products were also detected. The toxicity increased as a function of dose to 1.0 kGy. At doses higher than 1.0 kGy the toxicity decreased continuously due to further degradation. It was also demonstrated that the O2??/HO2? pair has low reactivity in CPL solution. 相似文献
106.
The effect of static external field is studied on the isotropic–nematic phase transition of a system of hard non-spherical particles (rods or platelets) with negative anisotropic polarizability (susceptabilities). On the basis of Onsager theory, the phase coexistence curve is calculated numerically without any approximation. It is found that a weakly ordered nematic phase (uniaxial planar) is in coexistence with a highly ordered biaxial nematic phase which ends at a tricritical point. In the limit of infinite field strength, the orientations of the particles are confined in a plane perpendicular to the field and continuous isotropic–nematic phase transition takes place. 相似文献
107.
Szilvia A. Nagy Mihaly Aradi Gergely Orsi Gabor Perlaki David Olayinka Kamson Andrea Mike Hedvig Komaromy Attila Schwarcz Arpad Kovacs Jozsef Janszky Zoltan Pfund Zsolt Illes Peter Bogner 《Magnetic resonance imaging》2013
Purpose
Our aim was to characterize bi-exponential diffusion signal changes in normal appearing white matter of multiple sclerosis (MS) patients.Methods
Diffusion parameters were measured using mono-exponential (0–1000 s/mm2) and bi-exponential (0–5000 s/mm2) approaches from 14 relapsing-remitting subtype of MS patients and 14 age- and sex-matched controls after acquiring diffusion-weighted images on a 3T MRI system. The results were analyzed using parametric or nonparametric tests and multiple linear regression models.Results
Mono-exponential apparent diffusion coefficient (ADC) slightly increased in controls (P=.09), but decreased significantly in MS as a function of age, nonetheless an elevated ADC was observed with increasing lesion number in patients. Bi-exponential analyses showed that the increased ADC is the result of decreased relative volume fraction of slow diffusing component (fs). However, the fast and slow diffusion components (ADCf, ADCs) did not change as a function of either age in controls or lesion number and age in MS patients.Conclusions
These data demonstrated that the myelin content of the white matter affects diffusion in relapsing-remitting subtype of multiple sclerosis that is possibly a consequence of the shift between different water fractions. 相似文献108.
Let $f$ be a Hecke–Maass cuspidal newform of square-free level $N$ and Laplacian eigenvalue $\lambda $ . It is shown that $\left||f \right||_\infty \ll _{\lambda ,\epsilon } N^{-\frac{1}{6}+\epsilon } \left||f \right||_2$ for any $\epsilon >0$ . 相似文献
109.
Gergely Zábrádi 《Israel Journal of Mathematics》2012,191(2):817-887
We prove that any projective coadmissible module over the locally analytic distribution algebra of a compact p-adic Lie group is finitely generated. In particular, the category of coadmissible modules does not have enough projectives. In the Appendix a “generalized Robba ring” for uniform pro-p groups is constructed which naturally contains the locally analytic distribution algebra as a subring. The construction uses the theory of generalized microlocalization of quasi-abelian normed algebras that is also developed there. We equip this generalized Robba ring with a selfdual locally convex topology extending the topology on the distribution algebra. This is used to show some results on coadmissible modules. 相似文献
110.
D. Nagy G. Szirmai P. Domokos 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,48(1):127-137
The spatial self-organization of a Bose-Einstein condensate (BEC) in a high-finesse linear optical cavity is discussed. The
condensate atoms are laser-driven from the side and scatter photons into the cavity. Above a critical pump intensity the homogeneous
condensate evolves into a stable pattern bound by the cavity field. The transition point is determined analytically from a
mean-field theory. We calculate the lowest lying Bogoliubov excitations of the coupled BEC-cavity system and the quantum depletion
due to the atom-field coupling. 相似文献