A new highly solid-state luminescent phase of a previously reported weakly luminescent CuI8PdII1 dicationic assembly is reported revealing the high geometrical versatility of this moiety that importantly alters its luminescent properties. This very minor new species Bc is based on a different conformer scaffold than the one encountered in the previously reported Bo form and, essentially differs from Bo by displaying shorter CuI-CuI intermetallic distances. DFT calculations allow concluding that the predominance in the solid-state of the weakly luminescent and less stable Bo phase is due to the extra stability induced by a larger number of intermolecular non-covalent π-CH interactions in its crystalline packing and not by the intrinsic stability of the CuI8PdII1 dicationic moiety. Calculations also revealed that a more stable conformation Bcalc is expected in vacuum, which bears a different distribution of CuI-CuI intermetallic distances than the dications in Bo and Bc phases. Taking into account that the geometrical alterations are associated to drastic changes of luminescence properties, this confer to the CuI8PdII1 assembly high potentiality as stimuli-sensitive luminescent materials. Indeed, by applying mechanical or thermal stress to samples of Bo phase, new phases Bg and Bm , respectively, were obtained. Alterations of the solid-state photophysical properties of these new species compared to those recorded for Bo are reported together with a combined experimental and computed study of the structures/properties relationships observed in these phases. 相似文献
The characterization of Mg–Co–Zr tri‐layer stacks using X‐ray fluorescence induced by X‐ray standing waves, in both the grazing‐incidence (GI) and the grazing‐exit (GE) modes, is presented. The introduction of a slit in the direction of the detector improves the angular resolution by a factor of two and significantly improves the sensitivity of the technique for the chemical characterization of the buried interfaces. By observing the intensity variations of the Mg Kα and Co Lα characteristic emissions as a function of the incident (GI mode) or detection (GE mode) angle, it is shown that the interfaces of the Si/[Mg/Co/Zr]×30 multilayer are abrupt, whereas in the Si/[Mg/Zr/Co]×30 multilayer a strong intermixing occurs at the Co‐on‐Zr interfaces. An explanation of this opposite behavior of the Co‐on‐Zr and Zr‐on‐Co interfaces is given by the calculation of the mixing enthalpies of the Co–Mg, Co–Zr and Mg–Zr systems, which shows that the Co–Zr system presents a negative value and the other two systems present positive values. Together with the difference of the surface free energies of Zr and Co, this leads to the Mg/Zr/Co system being considered as a Mg/CoxZry bi‐layer stack, with x/y estimated around 3.5. 相似文献
In order to study the influence of amine structure on absorption of carbon dioxide, enthalpies of solution of CO2 in 2.50 mol · L?1 aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol (THAM), 2-[2-(dimethyl-amino)ethoxy] ethanol (DMAEOE), and 3-dimethyl-amino-1-propanol (DMAP) were measured. The enthalpies of solution are determined as function of gas loading charge (moles of CO2/mole of amine), at temperatures (313.15 and 353.15) K, and pressures range from (0.5 to 2) MPa. Measurements were carried out using a flow calorimetric technique. CO2 solubilities in the aqueous solutions of amine are derived from calorimetric data. Molar volumes of aqueous amine solutions required to handle calorimetric data were determined at 303.15 K using a vibrating tube densimeter. Experimental enthalpies of solution are discussed on the basis of amines alkalinity. 相似文献
The electrochemical polymerization of polypyrrole films onto magnetically immobilized hydrophilic microbeads was carried out. Poly(pyrrole‐pyrene)‐microbeads coatings display thus higher permeability in water towards the diffusion of ferrocyanide than a pure poly(pyrrole‐pyrene) film. In addition, the modulation of this permeability through an applied magnetic field that attracts the microbeads on the electrode surface or pushes back them was shown. Moreover, a glucose biosensor was prepared by adsorbing and electropolymerizing on a platinum electrode, an aqueous mixture containing glucose oxidase, amphiphilic pyrrole monomer and microbeads attracted by a magnet. The presence of microbeads inside the biocoating, markedly increases the biosensor performance. 相似文献
Are you in? Bimetallic PtRu nanoparticles have been selectively confined inside or deposited outside carbon nanotubes (see picture). The confined nanoparticles display significantly higher selectivity and catalytic activity in hydrogenation reactions.
The effect of gelation of the polysaccharide phase on the phase separation was investigated for mixtures of anionic polysaccharide (kappa-carrageenan) and globular protein (beta-lactoglobulin) clusters at pH 7 well above the iso-electric point. Gelation of kappa-carrageenan was induced by cooling in the presence of KCl. In the liquid state the protein clusters phase-separate into relatively dense micro-domains. When the polysaccharide phase gelled during cooling, the turbidity of the systems decreased dramatically. Light scattering experiments showed that the density of the micro-domains decreased, while microscopy showed that the number and size was not strongly modified. It is concluded that smaller protein clusters leave the micro-domains when kappa-carrageenan gels. The effect could be reversed by reheating the samples and thus melting the gel and was observed for repeated heating and cooling cycles. The effect of gelation on phase separation decreases with increasing polysaccharide concentration and with ageing of the liquid mixture. The latter is caused by the formation of bonds between the protein clusters in the micro-domains that slowly reinforce with time. 相似文献
Replacing the Pro6 in the p6(Gag)-derived 9-mer "P-E-P-T-A-P-P-E-E" with N-substituted glycine (NSG) residues is problematic. However, incorporation of hydrazone amides ("peptoid hydrazones") can be readily achieved in library fashion. Furthermore, reduction of these hydrazones to N-substituted "peptoid hydrazides" affords a facile route to library diversification. This approach is demonstrated by application to Tsg101-binding compounds designed as potential HIV budding antagonists. [reaction: see text] 相似文献
We consider nonlinear finite-dimensional scalar-input control systems in the vicinity of an equilibrium.When the linearized system is controllable, the nonlinear system is smoothly small-time locally controllable: whatever and , the state can reach a whole neighborhood of the equilibrium at time T with controls arbitrary small in -norm.When the linearized system is not controllable, we prove that: either the state is constrained to live within a smooth strict manifold, up to a cubic residual, or the quadratic order adds a signed drift with respect to it. This drift holds along a Lie bracket of length , is quantified in terms of an -norm of the control, holds for controls small in -norm and these spaces are optimal. Our proof requires only regularity of the vector field.This work underlines the importance of the norm used in the smallness assumption on the control, even in finite dimension. 相似文献
We apply the phenomenological wetting theory of Cahn to fluids with van der Waals forces, and in particular to the wetting of pentane on water. Taking into account explicitly the long-range substrate–adsorbate interaction allows us to reproduce the experimentally observed critical wetting transition, which arises from the vanishing of the Hamaker constant at T53°C. This transition is preceded by a first-order transition between a thin and a thick film at a (much) lower temperature. If long-range forces are neglected, this thin–thick transition is the only wetting transition and critical wetting is missed. Our study focuses on the development of useful theoretical tools, such as phase portraits and interface potentials adapted to systems with van der Waals forces. 相似文献