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991.
992.
Cristina Canal Sandrine Villeger Benoit Rouffet Pilar Erra 《Applied Surface Science》2008,254(18):5959-5966
The efficiency of surface treatments by plasma and post-discharge plasma processes is greatly dependent on the density of active species, such as neutral atoms in post-discharges. Therefore, many diagnostics exist to detect the presence and measure the concentrations of these species, but they often require expensive instrumentation and highly qualified personnel. These conditions are not often met when the process is industrially used and it becomes important to imagine simple indicators allowing to validate that the correct operating conditions are reached. In the present paper, we present the first results on the investigation of an inexpensive and easy to use visual indicator able to quantify the atomic species density in nitrogen post-discharge plasma processes. It is based on the differential recombination coefficients of N-atoms on metallic/textile fibres which are intrinsically bonded together in a fabric matrix which serves as support for a thermochromic ink. The specific heating of the metallic fibres by N-atom recombination heats the whole of the fabric, leading to a visible colour change of the thermochromic ink, and therefore, of the indicator. Through modelling, it was possible to estimate that the inclusion of copper fibres to a pure cotton matrix leads to a 60% increase of the global N-atom recombination coefficient of the fabric, sufficient enough to provide a clearly visible colour change. 相似文献
993.
This paper describes the validation of a method for the determination of 24 priority substances from the European Framework Directive in estuarine and sea water using the new extraction technique known as stir bar sorptive extraction (SBSE), followed by thermal desorption using capillary gas chromatography-mass spectrometry. We studied linearity, detection and quantitation limits and accuracy (which includes determination of trueness and precision). Using the lack-of-fit method we tested linearity in the 0-200 ng L−1 range for all the priority substances. The detection and quantification limits were less than 5 and 10 ng L−1, respectively, for most of the compounds studied. Precision was assessed by variance analysis (ANOVA) and relative standard values of less than 10% were obtained for repeatability and less than 15% for intermediate precision. The recovery percentages in spiked estuarine and sea water were close to 100%. Finally, for quality control of the method (stability of precision and accuracy through time), we developed a method for calculating Shewhart control charts based on the information obtained in the validation process. 相似文献
994.
Cristina Canal Freddy Gaboriau Andre Ricard Miran Mozetic Uros Cvelbar Aleksander Drenik 《Plasma Chemistry and Plasma Processing》2007,27(4):404-413
Density of neutral oxygen atoms in the ground state has been measured during treatment of wool fabric samples. Samples were
placed in an afterglow reactor with a volume of about 5 l, which was pumped with a two stage rotary pump with the nominal
pumping speed of 28 m3/h. The source of the oxygen atoms was a microwave discharge operating in the surfatron mode at 2.45 GHz and adjustable output
power up to 300 W. The density of O-atoms in the afterglow chamber was measured with a fiber-optics catalytic probe. For the
empty reactor, the O density depended on discharge parameters and was between 0.8 and 2.8 × 1021 m−3 at 40 and 50 Pa respectively. During the treatment of wool, the O density depended largely on the exposure time. For untreated
samples, the O density was below the detection limit of the probe, while prolonged treatment allowed for recovering the O
density. The recovery always occurred after having submitted wool samples to the dose of the order of 1023 atoms/m2. The results were explained by oxidation of the thin lipid layer on the surface of the wool fibres. 相似文献
995.
We prove uniqueness of the good solution to the Cauchy–Dirichlet (C–D) problem for linear non-variational parabolic equations
with the coefficients of the principal part with discountinuities, in cases in which in general uniqueness of strong solutions
in Sobolev spaces does not hold. In particular, we prove uniqueness when the discontinuities of the coefficients are contained
in a hyperplane t = t
0 and, with an extra condition on the eigenvalues of the matrix, in a line segment x = x
0.
Mathematics Subject Classification. 35A05, 35K10, 35K20
Dedicated to the memory of Gene Fabes. 相似文献
996.
We introduce the notion ofα, λ-absolute continuity for functions of several variables and we compare it with the Hencl’s definition. We obtain that eachα, λ-absolutely continuous function isn, λ-absolutely continuous in the sense of Hencl and hence is continuous, differentiable almost everywhere and satisfies change
of variables results based on a coarea formula and an area formula. 相似文献
997.
Ramona Abbattista Ilario Losito Cristina De Ceglie Graziana Basile Cosima D. Calvano Francesco Palmisano Tommaso R.I. Cataldi 《Journal of mass spectrometry : JMS》2019,54(10):843-855
A systematic structural characterization of the isomeric forms related to ligstroside aglycone (LA), one of the most relevant secoiridoids contained in virgin olive oils, was performed using reverse phase liquid chromatography with electrospray ionization Fourier‐transform single and tandem mass spectrometry, operated in negative ion mode (RPLC‐ESI(?)‐FTMS and FTMS/MS). The high mass resolution and accuracy provided by the adopted orbital trap mass analyzer enabled the recognition of more than 10 different isomeric forms of LA in virgin olive oil extracts. They were related to four different types of molecular structure, two of which including a dihydropyranic ring bearing one or two aldehydic groups, whereas the others corresponded to dialdehydic open‐structure forms, differing just for the position of a C═C bond. The contemporary presence of enolic or dienolic tautomers associated to most of these compounds, stable at room temperature (23°C), was also assessed through RPLC‐ESI‐FTMS analyses operated under H/D exchange conditions, ie, by using D2O instead of H2O as co‐solvent of acetonitrile in the RPLC mobile phase. As discussed in the paper, the results obtained for LA indicated a remarkable structural similarity with oleuropein aglycone (OA), the most abundant secoiridoid of olive oil, whose isoforms had been previously characterized using the same analytical approach. 相似文献
998.
María V. de Glvez Jos Aguilera Cristina Snchez‐Roldn Enrique Herrera‐Acosta Enrique Herrera‐Ceballos 《Photochemistry and photobiology》2019,95(3):874-878
The potential role of infrared radiation in photodermatoses has received very little attention, even though the main sources of radiation used for photobiological studies (UVA, UVB and visible light) include infrared radiation. The objective of the work was to assess whether infrared radiation is involved in the development of skin lesions in patients with different types of photodermatoses. Twenty patients with different photodermatoses were exposed to UVA, UVB and visible radiation using a high‐pressure mercury UVA lamp, a fluorescent broadband UVB lamp, a tungsten bulb and a slide projector for visible radiation. Part of the radiation emitted by these lamps was water‐filtered to block infrared radiation above 1300 nm. All 20 patients developed lesions when exposed to different light sources used for phototest. When exposed to same sources without infrared radiation, 17 patients (85%) did not develop any lesions and the other three (15%) developed less severe lesions than in the area exposed to unfiltered light. Our results show that infrared radiation was necessary for the development of skin lesions in 85% of the patients with photodermatoses in our study. We believe that infrared radiation studies should be included in standard photobiology protocols. 相似文献
999.
1000.
Víctor Varela-Izquierdo Dr. Ana M. Geer Prof. Dr. Bas de Bruin Dr. José A. López Prof. Dr. Miguel A. Ciriano Dr. Cristina Tejel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(69):15915-15928
The feasibility of oxidative addition of the P−H bond of PHPh2 to a series of rhodium complexes to give mononuclear hydrido-phosphanido complexes has been analyzed. Three main scenarios have been found depending on the nature of the L ligand added to [Rh(Tp)(C2H4)(PHPh2)] (Tp= hydridotris(pyrazolyl)borate): i) clean and quantitative reactions to terminal hydrido-phosphanido complexes [RhTp(H)(PPh2)(L)] (L=PMe3, PMe2Ph and PHPh2), ii) equilibria between RhI and RhIII species: [RhTp(H)(PPh2)(L)]⇄[RhTp(PHPh2)(L)] (L=PMePh2, PPh3) and iii) a simple ethylene replacement to give the rhodium(I) complexes [Rh(κ2-Tp)(L)(PHPh2)] (L=NHCs-type ligands). The position of the P−H oxidative addition–reductive elimination equilibrium is mainly determined by sterics influencing the entropy contribution of the reaction. When ethylene was used as a ligand, the unique rhodaphosphacyclobutane complex [Rh(Tp)(η1-Et)(κC,P-CH2CH2PPh2)] was obtained. DFT calculations revealed that the reaction proceeds through the rate limiting oxidative addition of the P−H bond, followed by a low-barrier sequence of reaction steps involving ethylene insertion into the Rh−H and Rh−P bonds. In addition, oxidative addition of the P−H bond in OPHPh2 to [Rh(Tp)(C2H4)(PHPh2)] gave the related hydride complex [RhTp(H)(PHPh2)(POPh2)], but ethyl complexes resulted from hydride insertion into the Rh−ethylene bond in the reaction with [Rh(Tp)(C2H4)2]. 相似文献