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11.
Mihaela Frunza Gabriela Lisa M. I. Popa N. D. Miron Denisa Ileana Nistor 《Journal of Thermal Analysis and Calorimetry》2008,93(2):373-379
The thermal behavior of the new inorganic-organic nanohybrid materials obtained by intercalation of chloramphenicol and salicylate
into layered double hydroxides (LDHs) by direct synthesis method, anion exchange reaction and the reconstruction method was
evaluated by dynamic thermogravimetric analysis in air, at heating rates of 5°C min−1. The XRD patterns of the samples are characteristic for those of well crystallized solids with layered double hydroxide structures.
The FTIR spectroscopy results show the presence of the organic compound within the network structure of the synthesized LDHs.
The kinetic parameters (reaction order (n) apparent activation energy (E
a) and pre-exponential factor (lnA) were calculated by the Coats-Redfern method. The compensation effects were determined. 相似文献
12.
13.
D. E. Hole P. D. Townsend J. D. Barton L. C. Nistor J. Van Landuyt 《Journal of Non》1995,180(2-3):266-274
Data are reported on the size and depth distribution of gallium colloids formed by gallium ion implantation at energies of 50 and 60 keV, and nominal doses up to 1.1 × 1017 ions/cm2 into coverlip glass, float glass and white crown glass. Measurement techniques used to reveal colloid-induced changes include the wavelength dependence of optical reflectivity, transmission electron microscopy (TEM) and Rutherford backscattering (RBS). The reflectivity can be controlled by variations in ion dose, implant temperature and ion beam energy. The highest reflectivity is found after implants near 50°C and the level is extremely sensitive to the implant temperature. For controlled beam conditions, the reflectivity data are reproducible, despite there being variations in the colloid size and depth distributions as seen by TEM and RBS. The TEM data reveal that the depth distribution develops in two distinct regions, which at high concentration can precipitate into two layers of large colloids. Subsidiary experiments are reported to attempt to separate the effects of variations in the implant temperature and surface charging which influence the reflectivity, RBS and colloid formation. 相似文献
14.
Victor Nistor 《K-Theory》1991,5(3):193-211
We define a Chern character for p-summable quasihomomorphisms. We study its properties and show that it is compatible with the analytic index. The results are similar to Connes' results on the Chern character on K-homology but the methods are different. This solves most of a problem of Connes. 相似文献
15.
Luiza-Andreea Tnase Oana-Viorela Nistor Gabriel-Dnu Mocanu Doina-Georgeta Andronoiu Adrian Cîrciumaru Elisabeta Botez 《Molecules (Basel, Switzerland)》2022,27(22)
Galactagogue herbs, also known as natural lactation adjuvants, are frequently used to stimulate breast milk production. Due to their antioxidant activity and phenolic content, anise (Pimpinella anisum L.) and fennel (Foeniculum vulgare L.) were chosen to increase the added value of zucchini (Cucurbita pepo L.) purees. At the same time, this work aimed to determine the influence of heat treatment on various characteristics of the final product. The phytochemical content, color parameters, and rheological and textural parameters of zucchini purees enriched with herbal aqueous extracts were determined after processing and after one week of storage (4 °C). In the case of antioxidant activity, samples registered a variation between 6.62 ± 1.71 and 38.32 ± 3.85 µM Trolox/g DW for the samples processed by steam convection. The total difference color parameter (ΔE) increased seven times after one week of storage compared to samples at T0. Fennel and anise aqueous extracts helped improve the rheological behavior of zucchini samples both by steam and hot air convection. This study may serve as a springboard for future investigations and clinical trials into the scientific validity and safety of ready-to-eat foods with special destinations. 相似文献
16.
We compute K-theory invariants of algebras of pseudodifferential operators on manifolds with corners and prove an equivariant index theorem
for operators invariant with respect to an action of . We briefly discuss the relation between our results and the -invariant.
Submitted: September 1996, Revision: September 1997 相似文献
17.
A. Chevarier N. Chevarier A. Demeyer A. Alevra I.R. Lukas M.T. Magda M.E. Nistor 《Nuclear Physics A》1975,237(2):354-364
A study of the energy and angular distributions of protons emitted in 3He induced reactions was undertaken at an incident energy of 25.6 MeV. An analysis in the framework of the pre-equilibrium hybrid model did not succeed in explaining the overall behaviour of proton spectra; a contribution due to a break-up or a double stripping of the incident particle has to be taken into account. An attempt was made to account for these processes by performing a phase space calculation. This formulation was firstly tried in the case of deuteron induced reactions for which a break-up mechanism has already been confirmed in continuous proton spectra. The calculation extended to the case of 3He induced reactions showed that a double stripping mechanism could explain the observed distribution. 相似文献
18.
Nistor D. Miron N. D. Surpateanu G. G. Azzouz A. 《Journal of Thermal Analysis and Calorimetry》2004,76(3):913-920
The present work tries to emphasize the effect of acid/basis properties of montmorillonite type clays by ion exchange with
cations of different natures. The acidity and basicity measuring was made by thermo programated desorption (TPD)1,2, using
ammonia like basis agent and carbon dioxide like acid agent. With TPD method we can determine acid/basis proprietes by measuring
of the quantity of the ammonia and carbon dioxide termodesorbed. Clays are crystalline aluminosilicates, similar with the
zeolyts, who presents the property of ion exchanging. That propriety can be applicated for pollutants cations from aquatic
solutions. Ion exchanging propriety depends of a lot of factors: the cation nature, the valence and the ionic ray of the cation
present in the impregnated solution. That's an advantage for depollution process of heavy metals by fixing of these metals
by montmorillonite structure. By using TPD metod we can obtaine a caracteristic diagram.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
M. Craiu R. Marchidan E. Ivana A. Butucelea L. Nistor 《Reaction Kinetics and Catalysis Letters》1993,50(1-2):27-32
The formation of nickel oxide from Ni–Al takovite-like compounds has been investigated. Information about the stoichiometry of the NiO phase obtained by Diffuse Reflectance (DR) spectroscopy is discussed in connection with TPR and solubility data. 相似文献
20.
We study the approximation properties of a harmonic function u ∈ H1?k(Ω), k > 0, on a relatively compact subset A of Ω, using the generalized finite element method (GFEM). If Ω = ??, for a smooth, bounded domain ??, we obtain that the GFEM‐approximation uS ∈ S of u satisfies ‖u ? uS‖ ≤ Chγ‖u‖, where h is the typical size of the “elements” defining the GFEM‐space S and γ ≥ 0 is such that the local approximation spaces contain all polynomials of degree k + γ. The main technical ingredient is an extension of the classical super‐approximation results of Nitsche and Schatz (Applicable Analysis 2 (1972), 161–168; Math Comput 28 (1974), 937–958). In addition to the usual “energy” Sobolev spaces H1(??), we need also the duals of the Sobolev spaces Hm(??), m ∈ ?+. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006 相似文献