The Relationship between the Relative Solvating Power of Electrolytes and Shuttling Effect of Lithium Polysulfides in Lithium–Sulfur Batteries

Relative solvating power, that is, the ratio of the coordination ratios between a solvent and the reference solvent, was used to probe the quantitative structure–activity relationship of electrolyte solvents and the lithium polysulfide (LiPS) dissolution in lithium–sulfur batteries. Internally referenced diffusion‐ordered nuclear magnetic resonance spectroscopy (IR‐DOSY) was used to determine the diffusion coefficient and coordination ratio, from which the relative solvating power can be easily measured. The higher the relative solvating power of an ethereal solvent, the more severe will be the LiPS dissolution and the lower the coulombic efficiency of the lithium–sulfur battery. A linear relationship was established between the logarithm of relative solvating power of a solvent and the degree of LiPS dissolution, rendering relative solvating power an important parameter in choosing the electrolyte solvent for lithium–sulfur batteries.     

Direct Chemical Fine‐Tuning of Electronic Properties in Sc2Ir6−xPdxB

Crystal orbital Hamilton population (COHP) bonding analysis has predicted that ScPd₃B_0.5 is the least stable compound of the entire series Sc₂Ir_6?xPd_xB. Here, we report a systematic study of Sc₂Ir_6?xPd_xB (x=3, 5 and 6) by means of ¹¹B nuclear magnetic resonance (NMR), Knight shift (K) and nuclear spin‐lattice relaxation rate (1/T₁). NMR results combined with theoretical band structure calculations provide a measure of s‐ and non‐s‐character Fermi‐level density of states. We present direct evidence that the enhanced s‐state character of the Fermi level density of states (DOS) in ScPd₃B_0.5 reduces the strength of the B 2p and Pd 4d hybridized states across the entire Sc₂Ir_6?xPd_xB series. This hybridization strength relates to the opening of a deep pseudogap in the density of states of Sc₂IrPd₅B and the chemical bonding instability of ScPd₃B_0.5. This study is an experimental realization of a chemical fine‐tuning of the electronic properties in intermetallic perovskites.     

Filler segmentation of SEM paper images based on mathematical morphology

Recent developments in microscopy and image processing have made digital measurements on high-resolution images of fibrous materials possible. This helps to gain a better understanding of the structure and other properties of the material at micro level. In this paper SEM image segmentation based on mathematical morphology is proposed. In fact, paper models images (Whatman, Murillo, Watercolor, Newsprint paper) selected in the context of the Euro Mediterranean PaperTech Project have different distributions of fibers and fillers, caused by the presence of SiAl and CaCO3 particles. It is a microscopy challenge to make filler particles in the sheet distinguishable from the other components of the paper surface. This objectif is reached here by using switable strutural elements and mathematical morphology operators.     

Rapid syntheses of (±)-pterocarpans and isoflavones via the gold-catalyzed annulation of aldehydes and alkynes

(±)-Pterocarpan and analogues (4a-c) have been synthesized efficiently via the annulation of salicylaldehydes (1a, 1b and 1c) and o-methoxymethoxylphenylacetylene (2a), followed by a one-pot reduction and acidic cyclization of the ketones (3a-c). In addition, isoflavone derivatives (5a-c) have been synthesized rapidly, in two steps, via the annulation of salicylaldehyde (1a) and arylacetylenes (2b, 2c and 2d), followed by IBX/DMSO oxidation of the isoflavanones (3d, 3e and 3f).     

Analytical potential energy functions and theoretical spectroscopic constants for MX/MX− (MGe,Sn, Pb; XO,S, Se,Te, Po) and LuA (AH,F) systems: Density functional theory calculations

The molecular spectroscopic constants for the chalcogenide complexes MX (M?Ge, Sn, Pb; X?O, S, Se, Te, Po) and their corresponding MX^? anions are presented with the LSDA/SDD, B1LYP/SDD, and B3LYP/SDD methods. Although many methods were attempted, only the most promising results are reported. We show that the best results are obtained by LSDA/SDD calculations, and thus this method is emphasized as an illustrative example of our methodology. The potential energy curves and physical property characterizations for X¹ ∑⁺ state of LuH and LuF are presented with a variety of density functional theory (DFT) methods. Comparisons with wave function‐based treatments (HF, MP2, CCSD, QCISD) are made in addition to experimental correlations. We show that the best results are obtained by the B3LYP/SDD method for LuH, and the MPW1PW91/SDD method for LuF. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

A facile synthesis of new tetrahydropyrido[4,3-d]pyrimidine derivatives

The one-pot reaction of 1-benzylpiperidin-4-one with different nitriles in the presence of triflic anhydride affords substituted tetrahydropyrido[4,3-d]pyrimidines. Reaction with methylthiocyanate forms the corresponding methylthio substituted tetrahydropyridopyrimidines which can be easily converted into dimethoxy and dicarbonyl derivatives.     

Topologically Algebraic Algebras

We show that a locally convex algebra is topologically algebraic if, and only if, it is algebraic.Thanks are offered to Professor M. Oudadess for many remarks which allowed an improvement of the first version of this paper. We are also indebted to Professor A. Mallios for valuable suggestions.     

Cellulose Acetate-g-Polycaprolactone Copolymerization Using Diisocyanate Intermediates and the Effect of Polymer Chain Length on Surface,Thermal, and Antibacterial Properties

The need for biodegradable and biocompatible polymers is growing quickly, particularly in the biomedical and environmental industries. Cellulose acetate, a natural polysaccharide, can be taken from plants and modified with polycaprolactone to improve its characteristics for a number of uses, including biomedical applications and food packaging. Cellulose acetate-g-polycaprolactone was prepared by a three-step reaction: First, polymerization of ε-caprolactone via ring-opening polymerization (ROP) reaction using 2-hydroxyethyl methacrylate (HEMA) and functionalization of polycaprolactone(PCL) by introducing NCO on the hydroxyl end of the HEMA-PCL using hexamethyl lenediisocyanate(HDI) were carried out. Then, the NCO–HEMA-PCL was grafted onto cellulose acetate (using the “grafting to” method). The polycaprolactone grafted cellulose acetate was confirmed by FTIR, the thermal characteristics of the copolymers were investigated by DSC and TGA, and the hydrophobicity was analyzed via water CA measurement. Introducing NCO-PCL to cellulose acetate increased the thermal stability. The contact angle of the unreacted PCL was higher than that of cellulose acetate-g-PCL, and it increased when the chain length increased. The CA-g-PCL50, CA-g-PCL100, and CA-g-PCL200 showed very high inhibition zones for all three bacteria tested (E. coli, S. aureus, and P. aeruginosa).     

Chemical Composition Profiling and Antifungal Activity of Saffron Petal Extract

Numerous fungal plant pathogens can infect fresh fruits and vegetables during transit and storage conditions. The resulting infections were mainly controlled by synthetic fungicides, but their application has many drawbacks associated with the threatened environment and human health. Therefore, the use of natural plants with antimicrobial potential could be a promising alternative to overcome the side effects of fungicides. In this regard, this study aimed at evaluating the antifungal activity potential of saffron petal extract (SPE) against three mains important fungal pathogens: Rhizopus stolonifer, Penicillium digitatum and Botritys cinerea, which cause rot decay on the tomato, orange and apple fruits, respectively. In addition, the organic composition of SPE was characterized by attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopy and its biochemical, and gas chromatography-mass spectrometry (GC-MS) analyses were carried out. The obtained results highlighted an increased inhibition rate of the mycelial growth and spore germination of the three pathogenic fungi with increasing SPE concentrations. The mycelial growth and spore germination were completely inhibited at 10% of the SPE for Rhizopus stolonifer and Penicillium digitatum and at 5% for B. cinerea. Interestingly, the in vivo test showed the complete suppression of Rhizopus rot by the SPE at 10%, and a significant reduction of the severity of grey mold disease (37.19%) and green mold, when applied at 5 and 10%, respectively. The FT-IR spectra showed characteristic peaks and a variety of functional groups, which confirmed that SPE contains phenolic and flavonoid components. In addition, The average value of the total phenolic content, flavonoid content and half-maximal inhibitory concentration (IC₅₀) were 3.09 ± 0.012 mg GAE/g DW, 0.92 ± 0.004 mg QE/g DW and 235.15 ± 2.12 µg/mL, respectively. A volatile analysis showed that the most dominant component in the saffron petal is 2(5H)-Furanone (92.10%). Taken together, it was concluded that SPE could be used as an alternative to antioxidant and antifungal compounds for the control of postharvest diseases in fruits.     

Spectrophotometric study of the behaviour of pertechnetate in trifluoromethanesulfonic acid: effect of alpha irradiation on the stability of Tc(VII)

This paper is devoted to the stability of pertechnetate in trifluoromethanesulfonic acid (HTFMS) in presence or absence of alpha irradiation. The irradiations were performed using alpha particles (4He²⁺) generated by ARRONAX cyclotron with an external beam energy of 70 MeV. The stability has been determined by UV–Visible spectroscopy. In the absence of alpha irradiation, the results have shown that Tc(VII) is reduced in HTFMS between 4 and 11 M. UV–Visible spectroscopy measurements in 4–8 M show the presence of one phase of Tc(IV) oxopolymeric species. At 9 M HTFMS, the change of UV–Visible spectrum with respect to lower concentrations suggests the formation of a second new species of Tc(IV). At highly concentrated HTFMS (11 M), the Tc(VII) species remains stable. These findings exhibit the formation of reduced Tc species by partial thermal decomposition and hydrolysis processes due to the highly exothermic hydration reaction of triflic acid with water. Under alpha irradiation, the same reduced Tc species as those observed without external irradiation were obtained with higher reduction kinetics. The formation of oxopolymeric technetium at important radiolytic yield resulted from reducing radiolytic products of both water and acid.