共查询到20条相似文献,搜索用时 78 毫秒
1.
Daniela Aiello Luca Malfatti Tongjit Kidchob Rosario Aiello Flaviano Testa Iolinda Aiello Mauro Ghedini Massimo La Deda Tonino Martino Maria Casula Plinio Innocenzi 《Journal of Sol-Gel Science and Technology》2008,47(3):283-289
Highly fluorescent materials have been prepared by incorporation of a zinc complex in mesoporous silica thin films with ordered
pore structure. The zinc complex has been introduced into the mesoporous materials via impregnation in an ethanol solution.
The incorporation into the films has been monitored by UV–Vis, Fourier transform infrared spectroscopy and spectroscopic ellipsometry.
After 18 h of immersion in the doping solution the films showed strong blue emission, increase in the refractive index. Leaching
experiments performed by immersing the samples in ethanol or tetrahydrofuran have shown that the chromophore is retained in
the porous matrix.
相似文献
Plinio InnocenziEmail: |
2.
H. P. Zhang L. C. Yang L. J. Fu Q. Cao D. L. Sun Y. P. Wu R. Holze 《Journal of Solid State Electrochemistry》2009,13(10):1521-1527
Recent progress in studies of several types of core-shell structured electrode materials, including TiO2/C, Si/C, Si/SiO
x
, LiCoO2/C, and LiFePO4/C nanocomposites, including details of their preparation and their electrochemical performance is briefly reviewed. Results
clearly show that the coating shell can effectively prevent the aggregation of the nanosized cores, which are the electrochemically
active materials. In addition, the diffusion coefficients of lithium ions can be increased, and the reversibility of lithium
intercalation and deintercalation is improved. As a result, the cycling behavior is greatly improved. The reviewed results
suggest that core-shell nanocomposites are a good starting point for further development of new promising electrode materials.
相似文献
Y. P. WuEmail: |
R. Holze (Corresponding author)Email: |
3.
Saad Alshehri John Burgess Colin D. Hubbard Christopher J. Jones Amit K. Das 《Transition Metal Chemistry》2008,33(4):417-420
The kinetics of substitution by alcohols and by aniline at [tris(3,5-dimethylpyrazolyl)hydroborato]molybdenum nitrosyl dihalides in toluene solution at 298.2 K and at atmospheric pressure
are reported and interpreted in terms of an associative mechanism.
相似文献
Colin D. HubbardEmail: |
4.
S. Yu. Vassiliev A. I. Yusipovich Yu. E. Rogynskaya F. Kh. Chibirova A. M. Skundin T. L. Kulova 《Journal of Solid State Electrochemistry》2005,9(10):698-705
The difference in degradation behavior of titania-doped tin dioxide films is explained by a pronounced effect of the doping level on the film dispersity and fine distribution of titania. A two to three times decrease in nanoparticles sizes in the doped films compared with nanoparticles in SnO2 film (20–30 nm) is revealed by using scanning tunneling microscopy (STM). Such STM data (measured in ex situ configuration) combined with XRD and Mössbauer spectroscopy analysis confirm that the nanoparticles are composed of nanostructured heavily disordered SnO2 and TiO2 rutile solid solution or of amorphous phase containing both SnO2 and TiO2, the content of the crystalline and amorphous phases being approximately equal.
相似文献
S. Yu. VassilievEmail: |
5.
6.
Polystyrene/silica, polystyrene–butylacrylate/silica, silylated polystyrene/silica, and silylated polystyrene–butylacrylate/silica hybrid composites were synthesized by the sol–gel method in tetrahydrofuran using HCl as catalyst and tetraethylorthosilicate as the silica precursor. The polymers were characterized by fourier transform infrared (FTIR), nuclear magnetic resonance, and gel permeation chromatography. The sol–gel mixtures were cast on glass plates and dried in air at 30°C for 72 h. The composites were characterized by FTIR, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy analysis. Silica (12.8%) could be incorporated within the silylated polystyrene–butylacrylate matrix while retaining optical transparency. These composites showed better thermal stability and water resistance in comparison to the individual polymers.
相似文献
S. K DoluiEmail: |
7.
Vaporization enthalpies for the isomeric diazines were discussed within the context of recent measurements and estimation
techniques. It is suggested that pyridazine shows enigmatic behavior.
相似文献
Joel F. Liebman (Corresponding author)Email: |
8.
Garcia Jarem R. Peres Laura O. Fernandes Mauro R. Gruber Jonas Nart Francisco C. 《Journal of Solid State Electrochemistry》2004,8(2):122-126
In this communication we describe the electrochemical synthesis of poly(2,5-dicyano-p-phenylenevinylene) (DCNPPV) polymer films on indium tin oxide substrates. We investigate the purity, morphology, absorption and emission properties of the film. The purity was checked by infrared spectroscopy. The film formed presented spectroscopic purity equivalent to the chemically prepared PPV that was dialyzed for one week. Scanning electron microscopy of the surface revealed a grain-like morphology. The absorption and emission spectra showed absorption and emission bands at 420 nm and 575 nm, respectively, with the absorption onset at 422 nm, which corresponds to an energy gap of 2.25 eV. The electrochemical determination of the energy gap gives 2.05 eV, thus quite close to the optical energy gap at the onset of absorption. The EA and IP were determined by electrochemical measurements and are 3.46 eV and 5.51 eV, respectively.
相似文献
Francisco C. NartEmail: |
9.
The kinetic of the sol–gel hydrolysis and polycondensation reactions of a chiral ORMOSIL precursor was investigated by LCMS
technique as a function of water excess and pH. While the amount of water does not significantly change the kinetics, the
reactions strongly depend on the [H]+ concentration. At pH ≤ 3, the hydrolysis is very fast and the conversion of the precursor is completed within less than 1
h whereas at 80% of the precursor is still present after 50 h at pH = 3.5. This kinetic study allows to define a set of initial
conditions and time ranges required to provide good optical quality dip coated films .
相似文献
L. GuyEmail: |
10.
O. N. Zefirova L. A. Zasurskaya E. V. Nurieva N. V. Zyk N. S. Zefirov 《Structural chemistry》2007,18(4):461-464
Molecular structure of ethylene acetal of 3-trityloxymethylbicyclo[3.3.1]nonane-2-on-7-ol (3) was determined by X-ray investigation. It was revealed that 3 has endo-endo-configuration and adopt chair-boat-conformation. The distortion of rings was evaluated by calculation of the Zefirov–Palyulin and Cremer–Pople puckering parameters.
Failure of esterification of 3 was rationalized in terms of steric hindrance and intramolecular hydrogen bonding.
相似文献
O. N. ZefirovaEmail: |
11.
Guy Yardeni Israel Zilbermann Eric Maimon Haim Cohen Dan Meyerstein 《Research on Chemical Intermediates》2009,35(4):543-554
A new CeIII complex was synthesized by mixing the ligand “dioxocyclam” with CeIII ions at pH 8.0 and its redox properties were investigated.
相似文献
Dan Meyerstein (Corresponding author)Email: |
12.
Yan Gao Sabrina Reischmann Johannes Huber Tobias Hanke Rudolf Bratschitsch Alfred Leitenstorfer Stefan Mecking 《Colloid and polymer science》2008,286(11):1329-1334
Single semiconductor quantum dots were embedded into polymer particles with diameters below 0.1 μm by an emulsion polymerization
procedure or via a secondary dispersion approach. The photoluminescence properties of the nanocrystals are retained upon encapsulation,
as demonstrated by fluorescence confocal microscopy.
相似文献
Stefan MeckingEmail: |
13.
Niki Baccile Anna Fischer Beatriz Julián-López David Grosso Clément Sanchez 《Journal of Sol-Gel Science and Technology》2008,47(2):119-123
Core-shell and homogeneous distributions of functionalized cerium oxide nanoparticles within spray-dried mesostructured silica
spheres are achieved by modification of synthesis parameters such as the templating agent and nanoparticle capping functions.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Clément Sanchez (Corresponding author)Email: |
14.
In the present work, an important point concerning the NEMCA effect is addressed. We analyse the reasons why the changes in the work function of the gas exposed catalyst-electrode surface are one to one related to the changes in the catalyst working electrode potential E with respect to a reference electrode. It is concluded that this is due to the unique properties of the catalyst/solid electrolyte interface: the structure of the double layer in this region is very different from that in liquid electrolytes, being the potential difference at this interface mainly determined by the specific adsorption of the mobile species in the solid electrolyte.
相似文献
Ezequiel P. M. LeivaEmail: |
15.
Attila Sipos Miklós Tóth Franziska K. U. Mueller Jochen Lehmann Sándor Berényi 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):473-478
Abstract The synthesis of 4H-thiochromene derivatives of apomorphines, a novel class of isoquinoline alkaloid-related compounds, has been achieved by
different O-dealkylation methods applied on previously published heteroring-fused aporphinoids. Detailed DFT study has been presented
regarding the mechanism of the L-selectride-mediated multiple O-dealkylation of a seven-ring aporphine analogue. Dopamine-binding tests confirmed the essential function of 11-hydroxy moiety
of the aporphine skeleton and revealed a remarkable D1 over D2 specificity for the derivative having the 4H-thiochromene ring system attached to positions 2 and 3 of the aporphine backbone.
Graphical Abstract
相似文献
Attila SiposEmail: |
16.
Regina Mikulíková Václav Švorčík Josef Náhlík Tomáš Sopuch Pavel Havelka 《Cellulose (London, England)》2008,15(3):473-479
We studied the physical–chemical properties of polyethylene (PE) films doped with calcium salt of 6-carboxycellulose (Ca-oxy)
in concentrations 0–20 wt.% and their interactions with cells. The interaction between the PE/Ca-oxy composite film and 3T3
cells has not been described so far. Modification by surface grinding to enhance material cytocompatibility was studied. The
surface wettability of doped films was tested by contact angle measurements and the surface morphology by SEM microscopy and
profilometry. Adhesion and proliferation of tissue cells (3T3 mouse fibroblasts) were studied in vitro on pristine and ground
doped PE films. The ground samples have a higher contact angle values and the number of proliferated cells is greater on the
ground samples than on pristine ones. The presence of Ca-oxy in PE film increases the adhesion of 3T3 cells on the doped substrate
and on ground samples adhere more cells than on pristine ones.
相似文献
Václav ŠvorčíkEmail: |
17.
René Dybkaer 《Accreditation and quality assurance》2007,12(12):661-663
Terminology within a small laboratory community can be informal without danger of misunderstanding, but communication with
a wider audience and not least in publications, needs unequivocal terms for defined concepts. As an example, the many meanings
of “concentration” are explored to present a systematic nomenclature, including a concept diagram.
相似文献
René Dybkaer |
18.
Fatemeh Hashemzadeh M. Mehdi Kashani Motlagh Amir Maghsoudipour 《Journal of Sol-Gel Science and Technology》2009,51(2):169-174
In this work, MnO2 nanostructure powders with different crystalline phases have been successfully prepared by hydrothermal and sol–gel methods.
The obtained products were characterized by XRD and SEM techniques and their crystallographic phases and morphological properties
compared. Results showed that α-MnO2, β-MnO2, and δ-MnO2 nanorods were synthesized by hydrothermal method and γ-MnO2 polymorph was obtained by sol–gel method.
相似文献
Amir MaghsoudipourEmail: |
19.
Stephen L. R. Ellison 《Accreditation and quality assurance》2006,11(3):146-152
The relationship between calibrated range, residual standard deviation and correlation coefficient r is discussed. It is shown that in typical chemical calibration applications with appropriately distributed calibration points (particularly, with range comparable to mean and with approximately even or with ‘successive dilution’ spacing), the linear correlation coefficient has valid application as a routine criterion for acceptable fit if used with due care.
相似文献
Stephen L. R. EllisonEmail: Phone: +44-20-8943-7325Fax: +44-20-8943-2767 |
20.
The estimation of electrochemical quartz crystal microbalance (EQCM) frequencies from a given cyclic voltammetric data is analysed using underpotential deposition (UPD) of metals as an illustrative process. The crucial role played by the surface roughness of electrodes and electrosorption valency of the depositing species is pointed out. The computed EQCM frequency shifts for the UPD of Cd and Tl on polycrystalline Ag electrodes are in satisfactory agreement with the experimental data.
相似文献
M. V. SangaranarayananEmail: |