排序方式: 共有21条查询结果,搜索用时 15 毫秒
1.
The accuracy, precision, and reproducibility of a rapid method for determination of fluoride in wine, using a fluoride selective ion electrode, were established by a collaborative study involving 12 laboratories, 5 in Europe and 7 in the United States. The laboratories assayed 6 Youden pairs of fluoride-fortified, red and white wine samples with fluoride concentrations ranging from 0.2 to 3.0 mg/L. The relative standard deviations of repeatability ranged from 1.94 to 4.88%; relative standard deviations of reproducibility ranged from 4.15 to 18.40%. HORRAT values ranged from 0.30 to 0.97. The average recovery was 99.97%. Based on the statistical results of this collaborative study, the Study Director recommends that this method be adopted First Action. 相似文献
2.
Dr. Antonello Di Crescenzo Dr. Luca Bardini Dr. Bruna Sinjari Dr. Tonino Traini Dr. Lisa Marinelli Dr. Mauro Carraro Prof. Raimondo Germani Dr. Pietro Di Profio Prof. Sergio Caputi Prof. Antonio Di Stefano Prof. Marcella Bonchio Prof. Francesco Paolucci Prof. Antonella Fontana 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(48):16415-16423
Novel hydrogel phases based on positively charged and zwitterionic surfactants, namely, N‐[p‐(n‐dodecyloxybenzyl)]‐N,N,N‐trimethylammonium bromide (pDOTABr) and p‐dodecyloxybenzyldimethylamine oxide (pDOAO), which combine pristine carbon nanotubes (CNTs), were obtained, thus leading to stable dispersions and enhanced cross‐linked networks. The composite hydrogel featuring a well‐defined nanostructured morphology and an overall positively charged surface was shown to efficiently immobilise a polyanionic and redox‐active tetraruthenium‐substituted polyoxometalate (Ru4POM) by complementary charge interactions. The resulting hybrid gel has been characterised by electron microscopy techniques, whereas the electrostatic‐directed assembly has been monitored by means of fluorescence spectroscopy and ζ‐potential tests. This protocol offers a straightforward supramolecular strategy for the design of novel aqueous‐based electrocatalytic soft materials, thereby improving the processability of CNTs while tuning their interfacial decoration with multiple catalytic domains. Electrochemical evidence confirms that the activity of the catalyst is preserved within the gel media. 相似文献
3.
C. Bellecci G. E. M. L. Caputi F. De Donato P. Gaudio M. Valentini 《Il Nuovo Cimento C》1995,18(5):463-472
Summary In this report we introduce the infrared lidar-dial apparatus developed at the University of Calabria. It has been carried
out as a tool in the investigation of both the atmospheric pollution of trace gases and other atmospheric parameters as water
vapour. The general scheme of the station is described, as well as the performances of the home-made CO2 laser sources. Finally preliminary measurements of average concentration of ozone and water vapour over a range of about
3 km are presented and discussed in the report. 相似文献
4.
Multiwalled carbon nanotubes have been deposited on graphite cathodes by using an arc discharge technique in He atmosphere, with the insertion of a catalytic Ni-Cr mixture as well as without catalysers. The topography of such deposition has been investigated by SEM, while a parallel micro-Raman study has revealed, in particular regions of the deposited cathodes, strong bands in the range 1780-1860 cm−1, assignable to linear carbon chains inside the nanotubes. The variation of intensity, frequency and bandwidth of such bands has been investigated, in relation with the spectral characters of the host multiwalled carbon nanotube. In the cathode deposited without catalyst a quite ordered configuration of multiwalled carbon nanotubes is obtained in the central zone, while the maximum concentration of linear carbon chains is found in a ring shaped zone just inside the border. In sample obtained with catalyst the deposited multiwalled carbon nanotubes appear always more disordered, and a remarkable concentration of carbon chains appears in some zones, with a more casual distribution. 相似文献
5.
E. Colavita M. De Crescenzi L. Papagno L.S. Caputi G. Chiarello R. Scarmozzino R. Rosei 《Solid State Communications》1982,41(7):545-548
The electronic properties of the amorphous and sintered Fe80B20 alloys have been studied by electron energy loss spectroscopy. A correlation among energy loss data and X-ray absorption near edge structures has been attempted.Structure-related effects in the electronic properties of Fe80B20 alloy have been found and discussed. 相似文献
6.
Philipp Stephan Chloe Langley Daniela Winkler Dr. Jérôme Basquin Dr. Lorenzo Caputi Prof. Dr. Sarah E. O'Connor Dr. Hajo Kries 《Angewandte Chemie (International ed. in English)》2023,62(35):e202304843
Engineering of biosynthetic enzymes is increasingly employed to synthesize structural analogues of antibiotics. Of special interest are nonribosomal peptide synthetases (NRPSs) responsible for the production of important antimicrobial peptides. Here, directed evolution of an adenylation domain of a Pro-specific NRPS module completely switched substrate specificity to the non-standard amino acid piperazic acid (Piz) bearing a labile N−N bond. This success was achieved by UPLC-MS/MS-based screening of small, rationally designed mutant libraries and can presumably be replicated with a larger number of substrates and NRPS modules. The evolved NRPS produces a Piz-derived gramicidin S analogue. Thus, we give new impetus to the too-early dismissed idea that widely accessible low-throughput methods can switch the specificity of NRPSs in a biosynthetically useful fashion. 相似文献
7.
We present some EELS, SEE and K edge loss measurements on in situ cleaved graphite. Single particle excitations in the EELS measurements have been identified accordingly with some previous results on pure polycrystalline iron and are compared with available band structure calculations of graphite. The core edge loss spectroscopy performed in the reflection mode at low primary electron energy proved to be a powerful and rapid technique to study the partial density of empty states. 相似文献
8.
Mattivi F Caputi L Carlin S Lanza T Minozzi M Nanni D Valenti L Vrhovsek U 《Rapid communications in mass spectrometry : RCM》2011,25(4):483-488
Rotundone is an oxygenated sesquiterpene belonging to the family of guaianes, giving the 'peppery' aroma to white and black pepper and to red wines. Here we describe a novel, convenient protocol for the synthesis of rotundone, starting from a commercially available compound and requiring only two reaction steps, and an improved, faster method of GC separation (30 min) with selective quantisation of rotundone using tandem mass spectrometry in multiple reaction monitoring (MRM) mode with d(5)-rotundone as internal standard. With limits of detection (LODs) of 1.5 ng/L in white wine and 2.0 ng/L in red wine, intraday repeatability CV values of 6% and 5% at 50 ng/L and 500 ng/L and interday repeatability CV values of 13% and 6% at 50 ng/L and 500 ng/L, respectively, the improved protocol provides the desired sensitivity and selectivity for routine analysis of rotundone in both white and red wines. Initial application of this method highlighted the presence of unexpectedly high concentrations of rotundone, thus explaining the origin of the distinctive peppery aroma in Schioppettino and Vespolina red wines and in Gruener Veltliner white wines. 相似文献
9.
L.S. Caputi E. Colavita M.De Crescenzi S. Modesti L. Papagno R. Scarmozzino R. Rosei E. Tosatti 《Solid State Communications》1981,39(1):117-122
Electron energy loss measurements have been carried out in the reflection mode from polycrystalline iron. The observed structures are interpreted as surface and bulk collective losses by observing their dependence on the primary electron energy and surface oxidation. Interband transitions in the range 2–30 eV are pinpointed and found to be in excellent agreement with previous optical results, except for a new strong transition around 10 eV, which is not found in optical experiments. This transition is tentatively identified with a dipole-forbidden process, which becomes allowed because of finite momentum transfer by the electrons. 相似文献
10.
In this paper we extend to the hyperbolic space results firstly obtainedin Podestà and Spiro (Ann. Global Anal. Geom.
13(2) (1995), 169–184) for compact cohomogeneity, Riemannian manifoldsimmersed as hypersurfaces of the Euclidean space and in Seixas(Ph.D. Thesis, 1996), wherethe complete case was studied. Both works give sufficient conditionsfor the hypersurface to be of revolution. We study cohomogeneity, complete hypersurfaces of the hyperbolic space and prove a similar resultof Seixas (Ph.D. Thesis, 1996), obtaining also a class of nonrotational examples. 相似文献