Journal of Thermal Analysis and Calorimetry - The present work deals with thermal regulation of a spherical electronic device used in naval navigation techniques. Cooling is achieved by means of... 相似文献
In this paper, a new green pH-sensitive EDTA crosslinked HEC (cellulose-based hydrogel (swelling rate?~?1005%)) adsorbent was successfully elaborated. The synthesis of HEC-EDTA at the high advanced crosslinking degree (up to 92%), was carried out using DAEDT and DMAP as acyl transfer agent, where the lamellar morphology (2D-microstructure) was highly suggested based on the average functionality of the reaction system. The crosslinking degree was confirmed using structural analyzes (FTIR and 13C CP/MAS-NMR) and elemental profile analysis. The new EDTA crosslinked HEC demonstrated a high uptake capacity (~?2000 mg g?1) to aquatic micropollutants, especially methylene blue as cationic dyes model. The kinetic study showed that the adsorption process was well described by the pseudo-second-order kinetic, while the thermodynamic parameters exhibited a negative effect of temperature indicating a physical adsorption process. In addition, the adsorption capacity was studied varying to the experimental conditions (pH, contact time, concentration, etc.), and the Freundlich model revealed a strong correlation to the experimental data indicating an energetic heterogeneity of the surface active sites. Furthermore, using COMPASS II, the molecular dynamics (MD) simulations were conducted to optimize the chemical system, where the results showed the predominance of non-covalent molecular adsorbent-adsorbate interactions, which governs cluster design and configurations.
Migratory insertion of alkenes into gold–carbon bonds, a fundamental yet unprecedented organometallic transformation, has been investigated from a discrete (P,C) cyclometalated gold(III) dimethyl complex. Methide abstraction by B(C6F5)3 is shown to generate a highly reactive cationic AuIII complex that evolves spontaneously by C6F5 transfer from boron. In the presence of norbornene, migratory insertion into the Au C bond proceeds readily. The resulting norbornyl complex is efficiently trapped with pyridines or chloride to give stable four‐coordinate adducts. 相似文献
Within the framework of the Koiter's linear elastic shell theory, we study the limit model of a Lipschitz curved arch whose mid-surface is periodically waved. The magnitude and the period of the wavings are of the same order. To achieve the asymptotic analysis, we consider a mixed formulation, for which we perform a two-scale homogenization technique. We prove the convergence of the displacements, the rotation of the normal, and the membrane strain. From the limit formulation, we derive an effective model for curved critically wrinkled arches. It introduces two membrane strain functions—instead of one in the classical case—and exhibits a corrector membrane term to the coupling between the rotation of the normal and the membrane strain. 相似文献
In this paper, some complex linear differential equations are investigated. Many results on the relation between solutions and their derivatives are obtained. 相似文献
A low-cost, non-toxic and effective adsorbent constituted by a montmorillonite coated by iron oxides (montmorillonite–iron oxide composite) was prepared to assess its effectiveness in the removal of Cs+ and Sr2+ from aqueous solution. Dynamic adsorption experiments were carried out at room temperature under the effect of various operating parameters such as bed depth Z (5–15 cm), initial cation concentration C0 (2–50 mg L?1) and volumetric flow rate Q (0.5–8 mL min?1). Column performance has been modeled with constant-pattern wave approach combined to the Freundlich isotherm model and artificial neural network (ANN) models. The time, initial cation concentration, bed depth and volumetric flow rate were chosen as the input variables whereas, the outlet concentration Ct was considered as the output variable. The developed network was found to be useful in predicting the breakthrough curves. Experimental data for the used system were well fitted with ANN than the combined constant–pattern wave approach. 相似文献
Periodica Mathematica Hungarica - In this paper we present the well-defined solution of the following system of higher-order rational difference equations: $$begin{aligned}... 相似文献
The present work describes the metabolites produced by a strain identified as Streptomyces youssoufiensis, whose secondary metabolites profile has not been studied so far. The crude ethyl acetate extract was analyzed by high performance liquid chromatography-electrospray ionization mass spectrometry, leading to the detection of the ionophoric polyethers nigericin, epinigericin, abierixin and the newly isolated grisorixin methyl ester. The presence of epimeric forms of nigericin/epinigericin and grisorixin/epigrisorixin has spurred density functional theory computational calculations. This analysis was able to provide the relative stability of the most favored epimers, setting the basis for general structural considerations applicable to several other polyethers. Both nigericin sodium salt and grisorixin methyl ester showed to affect glioblastoma stem cells proliferation in a dose-dependent manner, with a higher activity for the more lipophilic grisorixin methyl ester (GI50 values of 3.85 and 3.05 μM for VIPI and COMI human glioblastoma stem cells, respectively). 相似文献