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排序方式: 共有136条查询结果,搜索用时 281 毫秒
111.
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Three Nematogen Azobenzene-Based Stationary Phases for Capillary GC: Synthesis and Comparative Study
Azzedine Addoun Ouassila Ferroukhi Mohamed Dahmane Saliha Guermouche Jean Pierre Bayle Moulay Hassene Guermouche 《Chromatographia》2014,77(19-20):1367-1377
In this paper, three laterally substituted liquid crystals termed LCC1, LCC3 and LCC4 were synthesized. Characterization of these substances was carried out by 1H NMR and 13C NMR; they possess similar core and differ in their lateral substituents. Their thermal stability was conducted by thermogravimetric analysis and showed decomposition beginning at 212, 233 and 264 °C related to LCC1, LCC3 and LCC4, respectively. Thermal properties were determined by differential scanning calorimetry, thermomicroscopy and inverse gas chromatography. The three novel compounds exhibited a nematic mesophase at a defined range of temperatures, which varied from 81 to 55 °C. Lengthening of the lateral substituent seemed to affect the nematic range by decreasing it. Fused-silica capillary columns (30 m × 0.32 mm) were employed for the analytical study. Numerous mixtures of components of various properties were injected. Particular attention was given to the selectivity towards the close-boiling isomers. These investigations indicated that lateral attached groups had considerable effect on the thermal and chromatographic properties of the liquid crystal compounds. These interesting results may guide in improving the development of new type of liquid crystals with desired properties for a widespread application. 相似文献
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Mohamed Bouhrim Salima Boutahiri Loubna Kharchoufa Hamza Mechchate Omkulthom Mohamed Al Kamaly Ali Berraaouan Bruno Eto Abderrahim Ziyyat Hassane Mekhfi Abdelkhaleq Legssyer Mohammed Aziz Mohamed Bnouham 《Molecules (Basel, Switzerland)》2021,26(8)
This study aims to assess the safety of the Opuntia dillenii (Ker-Gawl) haw. seed oil (ODSO) and its effect on the glucose absorption activity of the isolated rat hemidiaphragm. This oil’s safety was studied by exploring its acute (doses 1, 3, 5, and 7 mL/kg) and subacute (doses 1 and 2 mL/kg) toxicities in albino mice and Wistar rats, respectively. The safety of the ODSO was also assessed by studying its effect on the HepG2 cell viability in vitro. The effect of ODSO, or combined with the insulin, on the glucose absorption activity of isolated rat hemidiaphragm was evaluated at the dose 1 g/L in vitro. The results demonstrated the safety of ODSO. Indeed, this study showed that this oil does not produce any mortality or signs of toxicity after the single-dose administration in mice. Additionally, the daily intake of the ODSO during four weeks does not induce a significant variation in the biochemical parameters and body weight of rats compared with the control group. Besides, the cell viability of HepG2 did not change in the presence of ODSO. On the other hand, the ODSO increased the glucose absorption activity of the isolated rat hemidiaphragm, and this activity was significantly enhanced when combined with insulin. This study confirms, on one side, the safety of this oil and its efficacy and, on the other side, encourages its potential use as a complement to treat diabetes. 相似文献
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Prof. Chang Hyuck Choi Won Seok Choi Dr. Olga Kasian Dr. Anna K. Mechler Dr. Moulay Tahar Sougrati Dr. Sebastian Brüller Dr. Kara Strickland Dr. Qingying Jia Prof. Sanjeev Mukerjee Prof. Karl J. J. Mayrhofer Dr. Frédéric Jaouen 《Angewandte Chemie (International ed. in English)》2017,56(30):8809-8812
Fe-N-C catalysts with high O2 reduction performance are crucial for displacing Pt in low-temperature fuel cells. However, insufficient understanding of which reaction steps are catalyzed by what sites limits their progress. The nature of sites were investigated that are active toward H2O2 reduction, a key intermediate during indirect O2 reduction and a source of deactivation in fuel cells. Catalysts comprising different relative contents of FeNxCy moieties and Fe particles encapsulated in N-doped carbon layers (0–100 %) show that both types of sites are active, although moderately, toward H2O2 reduction. In contrast, N-doped carbons free of Fe and Fe particles exposed to the electrolyte are inactive. When catalyzing the ORR, FeNxCy moieties are more selective than Fe particles encapsulated in N-doped carbon. These novel insights offer rational approaches for more selective and therefore more durable Fe-N-C catalysts. 相似文献
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Frédéric Jamin Moulay Saı̈d El Youssoufi Christian Saix 《Comptes Rendus Mecanique》2004,332(2):153-159
A study of temperature influence on the yield surface for one unsaturated soil at constant suction is presented. Mechanical consolidation tests are realized at different temperatures on clayey silty sand. A specific triaxial apparatus for unsaturated soils with temperatures included between 30 °C and 60 °C is used. Experimental results show without ambiguity a thermo-extensive nature of the yield surface. The physical interpretation proposed calls for microscopic considerations on the menisci capillary evolution according to temperature and suction. To cite this article: F. Jamin et al., C. R. Mecanique 332 (2004). 相似文献
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E. Moulay 《Journal of Mathematical Sciences》2011,177(3):419-425
The aim of this article is to recall the main theorems of Morse theory and to infer some corollaries for the problem of Lyapunov stability on manifolds. It makes a link between Morse theory and the general theory of the Lyapunov stability for dynamical systems. 相似文献
120.
Emmanuel Moulay Sanjay P. Bhat 《Nonlinear Analysis: Theory, Methods & Applications》2010,73(4):1093-1097
Topological properties of the domain of attraction for dynamical systems are investigated. The main purpose of this paper is to prove that a compact, asymptotically stable attractor of a dynamical system defined on a locally compact metric space is a deformation retract of its domain of attraction, in a weak sense that is made precise. Under additional local assumptions, the attractor can be shown to be a retract, a deformation retract, or a strong deformation retract. The well known result that the domain of attraction of an asymptotically stable equilibrium is contractible follows as a corollary. 相似文献