共查询到20条相似文献,搜索用时 15 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.
The discovery and use of fluorescent proteins has revolutionized cellular biology. Despite the widespread use of visible fluorescent
proteins as reporters and sensors in cellular environments the versatile photophysics of fluorescent proteins is still subject
to intense research. Understanding the details of the photophysics of these reporters is essential for accurate interpretation
of the biological and biochemical processes illuminated by fluorescent proteins. Some aspects of the complex photophysics
of fluorescent proteins can only be observed and understood at the single-molecule level, which removes averaging inherent
to ensemble studies. In this paper we review how single-molecule emission detection has helped understanding of the complex
photophysics of fluorescent proteins.
相似文献
Vinod SubramaniamEmail: |
3.
Michael Noyong Buelent Ceyhan Christof M. Niemeyer Ulrich Simon 《Colloid and polymer science》2006,284(11):1265-1273
The formation and the optical features of two-dimensional aggregates formed by DNA-directed immobilization and cross-linking of bifunctional DNA–gold nanoparticles at flat gold substrates are analyzed. The samples are structurally characterized by atomic force microscopy to evaluate the particle size, the particle densities, and the degree of aggregation. The optical characteristics determined by UV/visible measurements are correlated with the structural features observed.
相似文献
Ulrich SimonEmail: |
4.
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: |
5.
Ina Reiche Stefan R?hrs Joseph Salomon Birgit Kanngie?er Yvonne H?hn Wolfgang Malzer Friederike Voigt 《Analytical and bioanalytical chemistry》2009,393(3):1025-1041
The paper presents an analytical method developed for the nondestructive study of nineteenth-century Persian polychrome underglaze
painted tiles. As an example, 9 tiles from French and German museum collections were investigated. Before this work was undertaken
little was known about the materials used in pottery at that time, although the broad range of colors and shades, together
with their brilliant glazes, made these objects stand out when compared with Iranian ceramics of the preceding periods and
suggested the use of new pigments, colorants, and glaze compositions. These materials are thought to be related to provenance
and as such appropriate criteria for art-historical attribution. The analytical method is based on the combination of different
nondestructive spectroscopic techniques using microfocused beams such as proton-induced X-ray emission/proton-induced γ-ray
emission, X-ray fluorescence, 3D X-ray absorption near edge structure, and confocal Raman spectroscopy and also visible spectroscopy.
It was established to address the specific difficulties these objects and the technique of underglaze painting raise. The
exact definition of the colors observed on the tiles using the Natural Color System?? helped to attribute them to different colorants. It was possible to establish the presence of Cr- and U-based colorants as
new materials in nineteenth-century Persian tilemaking. The difference in glaze composition (Pb, Sn, Na, and K contents) as
well as the use of B and Sn were identified as a potential marker for different workshops.
Figure UV fluorescence and visible spectroscopy are two of the non-destructive analytical methods used to investigate the coloring
agents of underglaze painted tiles. Imaging of the uranium-containing areas was carried out by UV photography and identification
of the chemical species by visible spectroscopy.
相似文献
Ina ReicheEmail: |
6.
Titania pillared zirconium phosphate (ZrP) and titanium phosphate (TiP) were prepared by intercalating Ti (IV) isopropoxide
sol in the interlayers of the mono sodium form of the corresponding metal phosphate. The sol-intercalated samples were activated
at various temperatures and characterized by XRD, UV–vis DRS, FTIR, BET-surface area, BJH-pore size distribution and acid
sites measurement. Basal spacing and surface area analyses revealed that highest amount of pillaring has taken place with
2 and 4 wt.% titania loading for ZrP and TiP, respectively. The photocatalytic degradation of 4-nitrophenol (4-NP), phenol,
methylene blue (MB) and hexavalent chromium (Cr (VI)) was studied in aqueous solution over the neat as well as pillared materials
under solar irradiation. Catalytic activity tests revealed that hexavalent chromium (Cr (VI)) and 4-nitrophenol (4-NP) were
completely degraded under acidic conditions, whereas, the same was observed in almost neutral conditions for phenol and methylene
blue (MB) over 0.6 g/L of catalyst.
相似文献
K. M. Parida (Corresponding author)Email: |
7.
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: |
8.
The advent of chemical tools for cellular imaging—from organic dyes to green fluorescent proteins—has revolutionized the fields
of molecular biology and biochemistry. Lanthanide-based probes are a new player in this area, as the last decade has seen
the emergence of the first responsive luminescent lanthanide probes specifically intended for imaging cellular processes.
The potential of these probes is still undervalued by the scientific community. Indeed, this class of probes offers several
advantages over organic dyes and fluorescent proteins. Their very long luminescence lifetimes enable quantitative spatial
determination of the intracellular concentration of an analyte through time-gating measurements. Their emission bands are
very narrow and do not overlap, enabling the simultaneous use of multiple lanthanide probes to quantitatively detect several
analytes without cross-interference. Herein we describe the principles behind the development of this class of probes. Sensors
for a desired analyte can be designed by rationally manipulating the parameters that influence the luminescence of lanthanide
complexes. We will discuss sensors based on varying the number of inner-sphere water molecules, the distance separating the
antenna from the lanthanide ion, the energies of excited states of the antenna, and PeT switches.
相似文献
Valérie C. PierreEmail: |
9.
Michael Thompson 《Accreditation and quality assurance》2008,13(8):479-482
The currently recommended design of collaborative trials (interlaboratory method performance studies) is examined in relation
to the usefulness of the resulting statistics. It is suggested that larger experiments, without duplicate analysis, would
be more informative.
相似文献
Michael ThompsonEmail: |
10.
Hinne Hettema 《Foundations of Chemistry》2008,10(2):135-142
Michael Weisberg’s recent 2007 paper on the chemical bond makes the claim that the chemical notion of the covalent bond is
in trouble. This note casts doubts on that claim.
相似文献
Hinne HettemaEmail: |
11.
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: |
12.
Electrochemical copolymerization of furan and 3-chlorothiophene was performed at constant electrode potential in a binary
solvent system consisting of boron trifluoride diethyl etherate + ethyl ether (BFEE + EE; ratio 1:2) and trifluoroacetic acid
(10% by volume). The homopolymers and copolymers obtained were studied with cyclic voltammetry, in situ ultraviolet–visible
spectroscopy, in situ resonance Raman spectroscopy, and in situ conductivity measurements. The spectroelectrochemical properties
of the copolymers show intermediate features between polyfuran and poly(3-chlorothiophene). The conductivity changes of homo-
and copolymer films are almost completely reversible when the potential shift direction is reversed.
相似文献
Rudolf HolzeEmail: |
13.
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: |
14.
Sarah Gold Julian Eastoe Roberto Grilli David C. Steytler 《Colloid and polymer science》2006,284(11):1333-1337
A series of highly branched trichain sulfosuccinate surfactants have been synthesized and studied in condensed CO2 and aqueous environments. Aqueous critical micelle concentrations (CMCs) showed a general trend of increasing CMC with decreasing chain length, whereas increased branching appeared to increase solubility in CO2 and aid the dispersion of water. Near infrared spectra confirmed observed cloud with a large increase in solubility above the cloud pressures in this solvent.
相似文献
Julian EastoeEmail: Phone: +44-117-9289180Fax: +44-117-9251295 |
15.
16.
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 |
17.
Abraham J. Qavi Adam L. Washburn Ji-Yeon Byeon Ryan C. Bailey 《Analytical and bioanalytical chemistry》2009,394(1):121-135
In the postgenomic era, information is king and information-rich technologies are critically important drivers in both fundamental
biology and medicine. It is now known that single-parameter measurements provide only limited detail and that quantitation
of multiple biomolecular signatures can more fully illuminate complex biological function. Label-free technologies have recently
attracted significant interest for sensitive and quantitative multiparameter analysis of biological systems. There are several
different classes of label-free sensors that are currently being developed both in academia and in industry. In this critical
review, we highlight, compare, and contrast some of the more promising approaches. We describe the fundamental principles
of these different methods and discuss advantages and disadvantages that might potentially help one in selecting the appropriate
technology for a given bioanalytical application.
相似文献
Ryan C. BaileyEmail: |
18.
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: |
19.
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: |
20.
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: |