排序方式: 共有26条查询结果,搜索用时 31 毫秒
1.
F. Aliotta M. E. Fontanella M. Pieruccini G. Salvato S. Trusso C. Vasi R. E. Lechner 《Colloid and polymer science》2002,280(2):193-202
The role played by the solvation water molecules on the macroscopically observed sol–gel transition in lecithin/cyclohexane/water
reverse micelles is investigated by quasielastic neutron scattering, dielectric relaxation and conductivity measurements.
The experimental results are juxtaposed to those from spherical Aerosol OT reverse micelles. It is shown how the results from
lecithin-based system can be interpreted only assuming that, in contrast to Aerosol OT systems, the water molecules are entrapped
at the interfaces without coalescing into an inner water pool. It is suggested that, in the case of lecithin, the solvation
water can induce a change in the surface curvature, in such a way promoting the formation of branch points. Such a hypothesis
is supported by the temperature dependence of the conductivity which agrees with the hypothesis of an intermicellar bond percolation.
The investigation of the structures imposed by an external electric field is also studied. The observed electrorheological
behaviour seems to confirm the existence of a percolated transient network in the gel phase.
Received: 21 March 2001 Accepted: 24 August 2001 相似文献
2.
Prof. Nunzio Tuccitto Gaetano Catania Prof. Andrea Pappalardo Dr. Giuseppe Trusso Sfrazzetto 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(55):13715-13718
The supramolecular detection by image analysis of a simulant chemical warfare agent on a solid device containing a selective molecular sensor based on a BODIPY scaffold is reported. The recognition properties were investigated in solution, demonstrating high affinity (log K 6.60) and sensitivity (LOD 10 ppt). A test strip also confirmed the sensing properties in gas phase. Image analysis of the solid device allows quantitative information about the simulant to be obtained, recovering the sensor almost 5 times and thus confirming the goal of the supramolecular approach. 相似文献
3.
P. Calandra D. Lombardo A. Pistone V. Turco Liveri S. Trusso 《Journal of nanoparticle research》2011,13(11):5833-5839
In this paper a novel hybrid approach to synthesise composite nanoparticles is presented. It is based on the laser ablation
of a bulk target (Yb) immersed in a reversed micellar solution which contains nanoparticles of a different host material (TiO2 nanoparticles) previously synthesised by chemical method. This approach thus exploits the advantages of the chemical synthesis
through reversed micellar solution (size control, nanoparticle stabilisation), and of the laser ablation (“clean” synthesis,
no side reactions). Central role is played by the microscopic processes controlling the deposition of the ablated Yb atoms
onto the surface of TiO2 nanoparticles which actually behave as nucleation seeds. The structural features of the resulting Yb@TiO2 composite nanoparticles have been studied by Transmission Electron Microscopy, whereas their peculiar optical properties
have been explored by UV–Vis spectroscopy and steady-state fluorescence. Results consistently show the formation of Yb and
TiO2 glued nanodomains to form nearly spherical and non-interacting nanoparticles with enhanced photophysical properties. 相似文献
4.
P. M. Ossi F. Neri N. Santo S. Trusso 《Applied Physics A: Materials Science & Processing》2011,104(3):829-837
Silver and gold thin films were deposited by pulsed laser ablation in a controlled Ar atmosphere at pressures between 10 and
100 Pa. Different morphologies, ranging from isolated nanoparticle arrays up to nanostructured thin films were observed. Fast
imaging of the plasma allowed deducing the expansion dynamics of the ablated plume. Plasma velocity and volume were used together
with the measured average ablated mass per pulse as input parameters in a model to estimate the average size of nanoparticles
grown in the plume. The nanoparticle size is expected to decrease from 4 nm down to 1 nm with decreasing Ar pressure between
100 and 10 Pa: this was confirmed by transmission electron micrographs which indicate a reduced dispersion of particle size
over narrow size ranges. The production of substrates for surface enhanced Raman scattering whose performances critically
depend on nanoparticle size, shape, and structure is discussed. 相似文献
5.
Summary The electrical-conductivity frequency dependence of reactive-evaporation-depositeda-Si:H films has been measured in the temperature range (100÷450)K. The influence of the substrate temperature, of the hydrogen
ions energy and of post-deposition thermal treatments has also been investigated. The results show that, depending on the
material quality, three different conduction mechanisms associated with gap states, band or band tail states and to hopping
processes near the Fermi level are observed. 相似文献
6.
E. Fazio S. Patanè S. Scibilia A.M. Mezzasalma G. Mondio F. Neri S. Trusso 《Current Applied Physics》2013,13(4):710-716
Nanocrystalline ZnO thin films were grown by means of pulsed laser deposition. The ablation process was carried out at relatively low background oxygen gas pressure (10 Pa) and by varying the substrate temperature up to 600 °C. Information on the structural and morphological properties of the deposited thin films have been obtained by means of X-ray photoelectron, Raman spectroscopies, X-ray diffraction (XRD) and atomic force microscopy (AFM). The results showed that all the deposited films are sub-stoichiometric in oxygen and with a hexagonal wurtzite crystalline structure, characterized by features of some tens of nanometers in size. An improvement of the films' crystalline quality was observed for the deposition temperature of 300 °C while the further increase of the deposition temperature up to 600 °C induces a worsening of the material's structural properties with the development of a large amount of nanoparticle's clusters. The analysis of the XRD patterns shows a growth crystallographic preferential direction as a function of the deposition temperature, in agreement with the appearance of the only E2 optical phonon mode in the Raman spectra. Such findings are compatible with the changes observed in the photoluminescent (PL) optical response and was related to the modification of the ZnO thin film structural quality. 相似文献
7.
Andrea Pappalardo Maria E. Amato Francesco P. Ballistreri Anna Notti Gaetano A. Tomaselli Rosa M. Toscano Giuseppe Trusso Sfrazzetto 《Tetrahedron letters》2012,53(52):7150-7153
Chiral diastereomeric cavitand-salen macrocycles have been synthesized by the high-dilution condensation of a tris-(quinoxaline-bridged)-diformyl-calix[4]resorcarene with (1R,2R)-diphenylethylenediamine. The reaction produced a couple of diastereoisomers, consisting of two cavitand cavities bis-bridged by two chiral diimino moieties, which differ in a convergent (C-shaped) or divergent (S-shaped) orientation of the two cavities. 相似文献
8.
A Pappalardo ME Amato FP Ballistreri GA Tomaselli RM Toscano G Trusso Sfrazzetto 《The Journal of organic chemistry》2012,77(17):7684-7687
A pair of diastereomeric salen cavitands and their uranyl complexes combine a chiral (R,R) salen bridge and an inherent chiral tris-bridged quinoxaline cup within the same molecule. Whereas the free ligands show a preference for the same enantiomer of an α-amino acid pair, the corresponding UO(2) complexes display opposite enantiodiscrimination and exceptionally high enantioselectivities (K(D)/K(L) = 26.4). 相似文献
9.
Vassil St. Georgiev Grace A. Bennett Lesley A. Radov Dietgard K. Kamp Laura A. Trusso 《Journal of heterocyclic chemistry》1986,23(5):1359-1362
The synthesis of a series of 2-substituted 2,3-dihydro-5H-thiazolo[2,3-b]quinazoline derivatives is described. Some of the title compounds exerted antiinflammatory and immunomodulating activities in laboratory animal models. 相似文献
10.
Summary We have performed extensive studies of a three-component microemulsion system composed of AOT-water-decane (AOT=sodium-bis-ethylhexyl-sulfosuccinate
is an ionic surfactant) using small-angle light scattering (SALS). The small-angle scattering intensities are measured in
the angular interval 0.001–0.1 radians, corresponding to a Bragg wave number range of 0.14 μm−1<Q<<1.4 μm−1. The measurements were made by changing temperature and volume fraction ϕ of the dispersed phase (water + AOT) in the range
0.05<ϕ<0.75. All samples have a fixed water-to-AOT molar ratio,w=[water]/[AOT]=40.8, in order to keep the same average droplet size in the stable one-phase region. With the SALS technique,
we have been able to observe all the phase boundaries of a very complex phase diagram with a percolation line and many structural
organizations within it. We observe at the percolation transition threshold, a scaling behavior of the intensity data. This
behavior is a consequence of a clustering among microemulsion droplets near the percolation threshold. In addition, we describe
in detail a structural transition from a droplet microemulsion to a bicontinuous one as suggested by a recent small-angle
neutron scattering experiment. The loci of this transition are located several degrees above the percolation temperatures
and are coincident with the maxima previously observed in shear viscosity. From the data analysis, we show that both the percolation
phenomenon and this novel structural transition are derived from a large-scale aggregation between microemulsion droplets. 相似文献