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91.
We study the exponential stability of linear skew-product semiflows on locally compact metric space with Banach fibers. Our main tool is the admissibility of a pair of the so-called Schäffer spaces. This characterization is a very general one, it includes as particular cases many interesting situations among them we can mention some results due to Clark, Datko, Latushkin, van Minh, Montgomery-Smith, Randolph, Räbiger, Schnaubelt. 相似文献
92.
Adriana Samide Petre Rotaru Cătălina Ionescu Bogdan Tutunaru Anca Moanţă Véronique Barragan-Montero 《Journal of Thermal Analysis and Calorimetry》2014,118(2):651-659
The thermal stability and the adsorption properties have been investigated for three benzothiazole compounds: 2-mercaptobenzothiazole (MBT), N-cyclohexyl-2-benzothiazole sulfenamide (NCBSA), and 2,2′-dibenzothiazole disulphide (BTD), reported in our early studies as corrosion inhibitors for carbon steel in different media. The electrochemical results were used to calculate the degree of surface coverage (θ). The adsorption mechanism of the three inhibitors was discussed according to the free energy of adsorption ( \( \Delta G_{{\text{ads}}}^{\circ } \) ) value obtained from Temkin adsorption isotherm, this being the best way to quantitatively express the adsorption process of their molecules on carbon steel surface. Thus, a mixed type mechanism involving the synergism between physisorption and chemisorption was proposed. The thermal analysis curves showed that, for the occurred events up to 470 °C, mass losses take place with endothermic effects followed by the total oxidation of the residue with an exothermic effect around 520 °C. Consequently, their effectiveness follows the order: BTD > NCBSA ≥ MBT, while the thermal stability ranges as follows: NCBSA < BTD ≤ MBT. 相似文献
93.
We present a multivalued nonlinear fixed point theorem in an E-metric space introducing the concept of strict positivity in a Riesz space. Our result extends some well-known fixed point theorems obtained by J. Matkowski, R. W?grzyk, R. Cristescu, and C. Çevik, I. Altun. 相似文献
94.
Dana A. Magdas Stela M. Cuna Petre Berdea Gabriela Balas Cornel Cuna Edina Dordai Mihaela C. Falub 《Rapid communications in mass spectrometry : RCM》2009,23(16):2568-2572
The Eastern Carpathians contain many mineral water springs that feed famous Romanian health resorts such as Borsec, Biborteni and Vatra Dornei. These waters have been used for their different therapeutic effects. In this work, mineral and spring waters from these Romanian regions were investigated by means of chemical and isotopic (δD and δ18O) analyses in order to understand the recharge mechanisms and also to determine their origins. Most of the investigated springs are of meteoric origin, having the average deuterium content of the local meteoric water. The higher 18O content with respect to the Meteoric Water Line (MWL) indicated an exchange reaction with crystalline igneous rocks at depth and with other rocks that the water encounters on its journey back to the surface. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
95.
A very general characterization of exponential dichotomy for evolutionary processes in terms of the admissibility of some pair of spaces which are translation invariant (the so-called Schäffer spaces) is given. It includes, as particular cases, many interesting situations among which we note the results obtained by N. van Minh, F. Räbiger and R. Schnaubelt and the authors concerning the connections between admissibility and dichotomy. 相似文献
96.
Mariana Tătucu Petre Rotaru Ileana Rău Cezar Spînu Angela Kriza 《Journal of Thermal Analysis and Calorimetry》2010,100(3):1107-1114
Pyridine derivative complexes are widely employed as biological active materials especially as antibacterial agents. Five transition metal(II) mpk complexes (mpk = methyl 2-pyridyl ketone) were synthesized and investigated using elemental analysis, spectroscopic techniques (IR and UV–Vis–NIR) and conductometric measurements. The general formulae established from experimental data were found to be [M(mpk)2(NO3)2]·xH2O (x = 0 for M = Cd(II), Zn(II), x = 2 for M = Cu(II)) and [M(mpk)2(H2O)2](NO3)2 (M = Co(II), Ni(II)). These compositions were further confirmed by thermal analysis and their thermal stability in dynamic air atmosphere investigated. 相似文献
97.
Claudiu Lăzăroaie Sorin Eşanu Ciprian Său Răzvan Petre Petrişor-Zamora Iordache Georgios Staikos Traian Rotariu Teodora Zecheru 《Journal of Thermal Analysis and Calorimetry》2014,115(2):1407-1415
Experimental researches were performed in order to determine the combustion temperatures and the visible and infrared screening performances of two pyrotechnic compositions used in decoy flare systems. Morphostructural and morphochemical analyses of the combustion solid products have been correlated with the combustion temperature. For the experimental studies, visible and infrared thermography have been employed, together with dedicated software. The comparative measurements indicated that the thermovision camera enables the acquisition of more accurate results versus the optical pyrometer in terms of data processing, and that the aluminum/polyhalogenated compounds–compositions present visible and infrared screening performances superior to those based on magnesium/polyhalogenated compounds. 相似文献
98.
Petre A. L. Auroux A. Gervasini A. Caldararu M. Ionescu N. I. 《Journal of Thermal Analysis and Calorimetry》2001,64(1):253-260
The surface properties of supported gallium oxide catalysts prepared by impregnation of various supports (γ-Al2O3, SiO2, TiO2, ZrO2) were investigated by adsorption microcalorimetry, using ammonia and water as probe molecules. In the case of acidic supports
(γ-Al2O3, ZrO2, TiO2), the acidic character of supported gallium catalysts always decreased in comparison with gallium-free supports; on very
weakly acidic SiO2, new acidic centers were created when depositing Ga2O3. The addition of gallium oxide decreased the hydrophilic properties of alumina, titania and zirconia, but increased the amount
of water adsorbed on silica. The catalytic performances in the selective catalytic reduction of NO by C2H4 in excess oxygenwere in the order Ga/Al2O3>Ga/TiO2>Ga/ZrO2>>Ga/SiO2. This order is more related to the quality of the dispersion of Ga2O3 on the support than to the global acidity of the solids.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
99.
The spherically symmetric solution of the Fokker-Planck equation with absorbing boundary is given in terms of a solution of an equivalent integral equation whose explicit form is found. 相似文献
100.
I. Gutu C. Petre I. N. Mihailescu M. Taca E. Alexandrescu I. Ivanov 《Optics & Laser Technology》2002,34(5):381-388
An effective method for surface heat treatment with 10.6 μm linear polarized laser beam at oblique incidence is reported. A circular focused laser spot on the workpiece surface, simultaneously with 2.2–4 times increasing of the absorption are obtained in the 70–80° range of the incidence angle. The main element of the experimental setup is the astigmatic focusing head which focalize the laser beam into an elliptical spot of ellipticity >3 at normal incidence. At a proper incidence angle (obtained by the focusing head tilting) the focused laser spot on the work piece surface gets a circular form and p-state of polarization is achieved.We performed laser heat treatment (transformation hardening, surface remelting) of the uncoated surface, as well as the alloying and cladding processes by powder injection. An enhancement of the processing efficiency was obtained; in this way the investment and operation costs for surface treatment with CO2 laser can be significantly reduced. Several technical advantages concerning the pollution of the focusing optical components, powder jet flowing and reflected radiation by the work piece surface are obtained. 相似文献