排序方式: 共有45条查询结果,搜索用时 234 毫秒
11.
Kojic acid (5-hydroxy-2-hydroxymethyl-4-pyrone) is known to have a high affinity for transition metals, and it and its derivatized cogeners are used both analytically and clinically. The interactions between kojic acid (KA) and eleven +3 metals (Al(+3), As(+3), Cr(+3), Ga(+3), Fe(+3), In(+3), Yb(+3), Y(+3), Gd(+3), Nd(+3), La(+3)) were examined by electrospray ionization mass spectrometry (ESI-MS) using an ion trap in an aqueous medium. For a subset of five ions, Fourier transform ion cyclotron resonance (FTICR)-MS was conducted to provide accurate mass confirmation of peak assignments for metals having clustering of abundant isotopes. KA readily formed complexes with all the metal ions tested. The most common complexes observed were ML(3)H(+) and M(2)L(5). Different behavior was seen for small and large ionic radius ions, with a relative cut-off between In(+3) ( approximately 80 pm) and Yb(+3) ( approximately 87 pm); a striking trend in % collision energy vs. cluster complexity was revealed. The KA-Cr(+3)complex shows a high affinity for H(2)O molecules in the gas phase, whilst In(+3) shows a preference for dimetal complexes and Y(+3) a deviant behavior when complexed to two neutrals. 相似文献
12.
Longano D Ditaranto N Cioffi N Di Niso F Sibillano T Ancona A Conte A Del Nobile MA Sabbatini L Torsi L 《Analytical and bioanalytical chemistry》2012,403(4):1179-1186
A new type of nanomaterial has been developed as antibacterial additive for food packaging applications. This nanocomposite
is composed of copper nanoparticles embedded in polylactic acid, combining the antibacterial properties of copper nanoparticles
with the biodegradability of the polymer matrix. Metal nanoparticles have been synthesised by means of laser ablation, a rising
and easy route to prepare nanostructures without any capping agent in a liquid environment. As prepared, nanoparticle suspensions
have been easily mixed to a polymer solution. The resulting hybrid solutions have been deposited by drop casting, thus obtaining
self-standing antibacterial packages. All samples have been characterized by UV–Vis spectroscopy, X-ray photoelectron spectroscopy
and electro-thermal atomic absorption spectroscopy. Ion release data have been matched with bioactivity tests performed by
Japanese Industrial Standard (JIS) method (JIS Z 2801:2000) against Pseudomonas spp., a very common Gram-negative microbial group able to proliferate in processed food. 相似文献
13.
de Carvalho Benini Kelly Cristina Coelho Ornaghi Heitor L. Pereira Paulo Henrique Fernandes Maschio Leandro José Voorwald Herman Jacobus Cornelis Cioffi Maria Odila Hilário 《Journal of Thermal Analysis and Calorimetry》2021,143(1):73-85
Journal of Thermal Analysis and Calorimetry - The effects of chemical treatment sequences on the chemical, physical, and mainly the thermal properties of Imperata Brasiliensis grass in the process... 相似文献
14.
Monticeli F. M. Ornaghi H. L. Cioffi M. O. H. Voorwald H. J. C. 《Mechanics of Composite Materials》2022,58(2):237-248
Mechanics of Composite Materials - The incorporation of two different reinforcements in the same matrix introduces distinct physical, mechanical, and chemical characteristics into it, which need to... 相似文献
15.
Angela?I.?López-LorenteEmail author Rosaria?A.?Picca Javier?Izquierdo Christine?Kranz Boris?Mizaikoff Cinzia?Di?Franco Soledad?Cárdenas Nicola?Cioffi Gerardo?Palazzo Antonio?Valentini 《Mikrochimica acta》2018,185(2):153
Hybrids consisting of silver nanoparticles (in varying fractions) and of TiOx/ZnO were prepared via top-down ion beam sputtering (IBS) deposition on silicon substrates. The deposited nanomaterials were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. It is shown that such composites represent a viable substrate for use in both surface enhanced Raman spectroscopy (SERS) and surface enhanced infrared absorption spectroscopy (SEIRAS), as exemplarily shown for crystal violet as the model analyte. The C-H bending mode at about 1181 cm?1 and the C-N vibration at 1361 cm?1 observed in the SERS and SEIRAS spectra, respectively, have been used as analytical signal. The substrate consisting of TiOx NPs with 33% fraction of silver provides the strongest enhancement in SERS (up to 10,000-fold), while TiOx/AgNPs with thickness of 2 and 1 nm in ion beam sputtering, respectively, provides the best sensitivity in SEIRAS. The substrates also display photocatalytic activity as shown by the degradation of adsorbed crystal violet under ultraviolet irradiation. 相似文献
16.
T.G. Cruz P.H.F. Pereira M.L.C.P. Silva M.O.H. Cioffi H.J.C. Voorwald 《Micron (Oxford, England : 1993)》2010,41(5):402-411
In this research the spatial distribution characterization of niobium phosphate into bleached cellulose was carried out combining processing and images analysis obtained by SEM and statistical methodologies. The objective is to investigate the deposit composition and phosphate morphology by using complementary analytical techniques. Based on the proposed methodology, parameters of niobium phosphate agglomerates (size and shape) and fiber morphology were evaluated depending on gray-levels (average luminance and fiber type): fiber characteristics (morphology) were measured. For the test method proposed, a specific region of cellulose/NbOPO4·nH2O composite was analyzed. This method involves area fraction measuring with a conditional probabilistic analysis. The analyzed fields were divided in different ways, called ‘Scanning’ and as a result, in quantitative terms, the phosphate deposition was described as spatial distribution homogeneous or inhomogeneous. The quantitative microscopy as a non-destructive testing provides relevant information when it is combined with statistic analysis. 相似文献
17.
Given a collection of accepted risks with corresponding impacts and probabilities over the life of a project (or a relevant portion), a method to estimate the total potential impact at a given certainty is presented. Project sponsors and managers can decide their risk tolerance and set aside corresponding contingency funds. This analytic method uses a binomial distribution with a probability equal to the risks’ average probability. At a desired statistical confidence level, the number of risks to consider is determined, and risks are ranked in descending order of either impact or expected value of impact. The ranked risks’ impacts are then summed over the specified number of risks, leading to an appropriate contingency budget. The budget found with this method compares extremely well with the one ascertained from numerical simulations of the risk occurrences. 相似文献
18.
The system 4CaO·3Al2O3·SO3-CaSO4·2H2O-Ca(OH)2 was hydrated in the presence of ten dopants, specifically soluble salts of heavy metals.When added in 10% amount, the effect of each salt is strongly evident at shorter curing times, the hydration kinetics being more favoured in the order Pb(NO3)22CrO4< Cd(NO3)2< Zn(NO3)2t~Mn(NO3)3=K2MoO43)23)23)33)3. At longer curing times the differences among the systems decrease significantly.The 28-day compressive strength is almost the same for all the systems except those containing Pb(NO3)2, K2MoO4 and K2CrO4. 相似文献
19.
Rosa Pilolli Nicoletta Ditaranto Nicola Cioffi Luigia Sabbatini 《Analytical and bioanalytical chemistry》2013,405(2-3):713-724
In the present, contribution angle-resolved X-ray photoelectron spectroscopy (AR-XPS) was proposed as a useful tool to address the challenge of probing the near-surface region of bio-active sensor surfaces. A model bio-functionalised surface was characterised by parallel AR-XPS and commercially available Thermo Avantage-ARProcess software was used to generate non-destructive concentration depth profiles of protein-functionalised silicon oxide substrates. At each step of the functionalisation procedure, the surface composition, the overlayer thickness, the in-depth organisation and the in-plane homogeneity were evaluated. The critical discussion of the generated profiles highlighted the relevance of the information provided by PAR-XPS technique. Figure
Schematic representation of the functionalization procedure along with the generated profiles 相似文献
20.
Cotugno P Monopoli A Ciminale F Cioffi N Nacci A 《Organic & biomolecular chemistry》2012,10(4):808-813
Pd nanoparticles generated in green reaction media (viz. ionic liquids and water) catalyze the one-pot sequential Heck and Suzuki coupling reactions of bromo-chloroarenes to afford unsymmetrically substituted arenes in good yields. 相似文献