排序方式: 共有11条查询结果,搜索用时 15 毫秒
1.
H. Elmsellem M. H. Youssouf A. Aouniti T. Ben Hadda A. Chetouani B. Hammouti 《Russian Journal of Applied Chemistry》2014,87(6):744-753
The inhibition effect of curcumin on the corrosion of mild steel in 1.0 M HCl solution was studied by weight loss, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) methods. The experimental results suggest that this compound is an efficient corrosion inhibitor and the inhibition efficiency increases with the increase in inhibitor concentration. Adsorption of this compound on mild steel surface obeys Langmuir isotherm. Also the objective of this work is to attempt to find relationships between electronic structure and inhibition efficiency. The structural parameters, such as the frontier molecular orbital energies (E HOMO and E LUMO), gap of energy ΔE, from the molecule to iron as well as electronic parameters such as Mulliken atomic populations were calculated and discussed using the Density Functional Theory method (DFT). 相似文献
2.
In order to rationalize the effect of the size and coordinating ability of counteranions upon the structure of Ag(I)–dithioether coordination polymers, a series of such polymers has been synthesized by the combination of the 1,3-bis(methylthio)propane building block and AgX silver salts (X = ClO4− (1), BF4− (2), CF3SO3− (3), SbF6− (4), C6H5COO− (5), CF3COO− (6), CF3CF2CF2COO− (7) and −OOCCF2CF2COO− (8)). Except in two cases, all complexes form 1D-coordination polymers. 相似文献
3.
Youssouf Dieng 《Archiv der Mathematik》1980,34(1):322-343
Sans résumé 相似文献
4.
Mathilde Pantin Florent Bodinier Jordan Saillour Yassine M. Youssouf Fabien Boeda Morwenna S.M. Pearson-Long Philippe Bertus 《Tetrahedron》2019,75(33):4657-4662
A convenient access to 2-hydroxycyclopentenones was designed from acylcyanohydrins, by using titanacyclopropane complexes as nucleophilic partners and an intramolecular aldol condensation in basic conditions. The development of a one-pot procedure allows a step- and atom-economic process, and the use of Grignard reagents other than ethylmagnesium bromide provided valuable 3,4-disubstituted 2-hydroxycyclopentenones. The utility of the hydroxy group was illustrated by further functionalization of the α-position using palladium-mediated cross-coupling reactions. 相似文献
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6.
One-step vs stepwise immobilization of 1-d coordination-based rh-rh molecular wires on gold surfaces
KS Lokesh S Chardon-Noblat F Lafolet Y Traoré C Gondran P Guionneau L Guérente P Labbé A Deronzier JF Létard 《Langmuir : the ACS journal of surfaces and colloids》2012,28(32):11779-11789
Reaction of dimeric [Rh(II)(2)(phen)(2)(μ-OAc)(2)(MeCN)(2)](BF(4))(2) (phen =1,10-phenanthroline) with pyrazine (pz) in a 1:2 ratio leads to the new 1-D metal-metal-bonded coordination oligomer {[Rh(II)(2)(phen)(2)(μ-OAc)(2)(pz)](BF(4))(2)}(n) (Rh-Rhpz)(n) (1), where each Rh atom of the dimeric unit (Rh-Rh) is coordinated in the equatorial plane to a nitrogen atom of a rigid and linear bifunctionalized organic linker (pz). Single X-ray diffraction analysis reveals the 1-D straight oligomeric chain structure (molecular wire, MW) consists of alternating (Rh-Rh) units and pz linking ligands with free BF(4)(-) as counteranions, and each metal center has a slightly distorted octahedral arrangement. The presence of accessible labile MeCN groups on both ends of these MWs ("free ends") enables functionalization of a 4-mercaptopyridine-gold coordinating platform (Au/MP) to form in one step a layer of coordination oligomer (Au/MP(Rh-Rhpz)(n); n ≈ 50). Furthermore (Rh-Rhpz)(n) (n = 1-6) MWs were grafted to Au/MP surfaces by a conventional step-by-step assembly construction involving coordination reactions between the Rh dimer ([Rh(2)(phen)(2)(μ-OAc)(2)(MeCN)(2)](BF(4))(2) (2)) and pz. A detailed physicochemical study (UV-vis, RAIR, QCM-D, ellipsometry, contact angle measurements, as well as impedance spectroscopy and cyclic voltammetry) has been made during both assembly methods to characterize the resulting surface-anchored coordination molecular wire (CMW) layers (Au/MP(Rh-Rhpz)(n)). The results indicate that the immobilized molecular assemblies (MAs) were successfully fabricated using both methods of assembly. The efficiency of the two methods is discussed. 相似文献
7.
Protein separation and surfactant control of electroosmotic flow in poly(dimethylsiloxane)-coated capillaries and microchips 总被引:3,自引:0,他引:3
Badal MY Wong M Chiem N Salimi-Moosavi H Harrison DJ 《Journal of chromatography. A》2002,947(2):277-286
A thermally pyrolyzed poly(dimethylsiloxane) (PDMS) coating intended to prevent surface adsorption during capillary electrophoretic (CE) [Science 222 (1983) 266] separation of proteins, and to provide a substrate for surfactant adsorption for electroosmotic mobility control was prepared and evaluated. Coating fused-silica capillaries or glass microchip CE devices with a 1% solution of 100 cSt silicone oil in CH2Cl2, followed by forced N2 drying and thermal curing at 400 degrees C for 30 min produced a cross-linked PDMS layer. Addition of 0.01 to 0.02% Brij 35 to a 0.020 M phosphate buffer gave separations of lysozyme, cytochrome c, RNase, and fluorescein-labeled goat anti-human IgG Fab fragment. Respective plates/m typically obtained at 20 kV (740 V cm(-1)) were 2, 1.5, 1.25, and 9.4-10(5). In 50 mM ionic strength phosphate, 0.01% Brij 35 running buffer, the electroosmotic flow observed was about 25% of that in a bare capillary, and showed no pH dependence between pH 6.3-8.2. Addition of sodium dodecylsulfate (SDS) or cetyltrimethylammonium bromide (CTAB) to this running buffer allowed ready control of electroosmotic mobility, mu(eo). Concentrations of SDS between 0.005 to 0.1% resulted in mu(eo) ranging from 3 to 5 x 10(-4) cm2 V(-1) s(-1). Addition of 1 to 2.3 x 10(-4)% (2.7-6.3 microM) CTAB caused flow reversal. CTAB concentrations between 3.5 x 10(-4) and 0.05% (0.0014-1.37 mM) allowed control of mu(eo) between -1 x 10(-4) and -5.0 x 10(-4) cm2 V(-1) s(-1). For both surfactants the added presence of 0.01% Brij 35 provided slowly varying changes in mu(eo) with charged surfactant concentration. 相似文献
8.
Background
In Drosophila, cuticular sex pheromones are long-chain unsaturated hydrocarbons synthesized from fatty acid precursors in epidermal cells called oenocytes. The species D. melanogaster shows sex pheromone dimorphism, with high levels of monoenes in males, and of dienes in females. Some biosynthesis enzymes are expressed both in fat body and oenocytes, rendering it difficult to estimate the exact role of oenocytes and of the transport of fatty acids from fat body to oenocytes in pheromone elaboration. To address this question, we RNAi silenced two main genes of the biosynthesis pathway, desat1 and desatF, in the oenocytes of D. melanogaster, without modifying their fat body expression. 相似文献9.
Sergey Lozenko Djibril Faye Haitao Zhang Mélanie Lebental Joseph Lautru Joseph Zyss Jean-Pierre Lefevre Isabelle Leray 《Applied physics. B, Lasers and optics》2014,117(1):501-508
We report the design, fabrication, and demonstration of a chemical sensor-based on the spectral shift of organic microcavity lasers. The shape of the cavity contour is used as a parameter and is optimized to improve the sensitivity. Analytical and numerical predictions are in good agreement with experiments performed in a microfluidic environment, showing sensitivities of up to 100 nm per refractive index unit for stadium-shaped microlasers on pedestal. Selective sensing of Hg2+ at a concentration down to 200 ppb is then demonstrated with cavities functionalized by ligands that are known to bind mercuric cations. 相似文献
10.
A novel acetogenin, cis-bullatencin, was isolated by successive chromatography of a cyclohexane extract of Uvaria chamae P. Beauv. roots. The structure was elucidated by a combination of chemical and spectroscopic methods (NMR, MS). Eight known mono-THF acetogenins--bullatencin, annotemoyin-1, solamin, uvariamicin-I, -II, -III, cis-reticulatacin and cis-uvariamicin-I--were also obtained. 相似文献