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1.
Zaharescu M. Jitianu A. Brăileanu A. Madarász J. Novák CS. Pokol G. 《Journal of Thermal Analysis and Calorimetry》2003,71(2):421-428
Hybrid materials with different amounts of organics permanently bound on the inorganic network obtained in the TEOS-MTEOS
(tetraethoxysilan-methyltriethoxysilan) system are used for obtaining coatings with different optical and mechanical properties.
To study the thermal stability of the mentioned materials, compositions with different molar ratios of the precursors were
prepared. The influence of the solvent and water amounts on the gelation process was also investigated. The gels obtained
were characterised by IR spectrometry and their decomposition temperatures were determined by DTA/TG. Thermal stability of
the gels is rather influenced by their composition than the conditions of the gelation process.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
J. Somlai B. Kanyár R. Bodnár CS. Németh Z. Lendvai 《Journal of Radioanalytical and Nuclear Chemistry》1996,207(2):437-443
A significant dose contribution on the population could be derived from coal slags used as isolation material. Extremely high natural activities are measured in the coal slag, derived from the region of the settlement Ajka, Hungary. In some buildings monitored, the elevated -doses were nearly 5–10 times higher than the world average ones. The annual average indoor radon concentrations from the slag exceeded 400 Bq/m3 and in some cases up to 1200 Bq/m3. Due to the elevated exposure and the radon concentrations in the dwellings the annual dose was estimated to 8–24 mSv/y more than 5–10 times of the world average one. 相似文献
3.
A. GARAY S. DEMETER K. KOVÁCS G. HORVÁTH ÁGNES FALUDI-DÁNIEL 《Photochemistry and photobiology》1972,16(2):139-144
Abstract— Circular dichroism (CD) spectra were studied in System I particles prepared by digitonin fragmentation of chloroplasts of normal maize and carotenoid-deficient mutants. CD bands of pigment molecules were found to be higher in particles than in solutions. This phenomenon was most pronounced for the particles containing the carotenoid composition of normal chloroplast lamellae. The CD signal of chlorophylls bound to particles of carotenoid-deficient chloroplasts was closer to that found in solutions. This indicates that aggregation and/or binding of chlorophylls in carotenoid-deficient mutants may be less extensive than in normal chloroplasts. 相似文献
4.
Dorothée Goffin Christelle Robert Bernard Wathelet Christophe Blecker Yves Malmendier Michel Paquot 《Chromatographia》2009,69(3-4):287-293
In this paper, anion exchange chromatography coupled with pulsed amperometric detection has been successfully applied for the fine analysis of isomaltooligosaccharides (IMO) syrups where previous reported methods suffered from a lack of homologue oligosaccharides resolution. These syrups are made of a very complex mixture of glucose oligosaccharides characterized at the same time by their DP value (from 2 to ~15) and linkage types [α-(1–2, 3 or 6) and non-IMO α-(1–4)] and position. A mix of available commercial standards (17 species) was completely separated on a CarboPac PA-100 column at a flow rate of 1 mL min?1 and with a gradient of sodium acetate in 100 mM sodium hydroxide. The method was validated according to calibration curve, precision, recovery tests, limits of detection and quantitation. Calibration curves presented correlation coefficients greater than 0.98. The analytical method has been applied on real syrups, keeping a high performance separation of structurally close molecules and giving, for six determinations, very low relative SD for the available standard molecules (0.3–5.8%). The accuracy of the proposed method was tested by recovery measurements: first by spiking maltose on three different syrups and then by spiking six different sugar standards (20, 50 and 75% of the initial content) on a single syrup. Good recovery results (respectively, 96.5–99.7 and 97.1–102.7%) were found. The method was found sensible with limits of detection (signal-to-noise ratio of 3) between 0.048 and 0.124 μg mL?1 and limits of quantification (signal-to-noise ratio of 10) between 0.159 and 0.412 μg mL?1. 相似文献
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The distance function \({\varrho(p, q) ({\rm or} d(p, q))}\) of a distance space (general metric space) is not differentiable in general. We investigate such distance spaces over \({\mathbb{R}^n}\), whose distance functions are differentiable like in case of Finsler spaces. These spaces have several good properties, yet they are not Finsler spaces (which are special distance spaces). They are situated between general metric spaces (distance spaces) and Finsler spaces. We will investigate such curves of differentiable distance spaces, which possess the same properties as geodesics do in Finsler spaces. So these curves can be considered as forerunners of Finsler geodesics. They are in greater plenitude than Finsler geodesics, but they become geodesics in a Finsler space. We show some properties of these curves, as well as some relations between differentiable distance spaces and Finsler spaces. We arrive to these curves and to our results by using distance spheres, and using no variational calculus. We often apply direct geometric considerations. 相似文献
8.
Ronkart SN Blecker CS Fourmanoir H Fougnies C Deroanne C Van Herck JC Paquot M 《Analytica chimica acta》2007,604(1):81-87
In this study, inulooligosaccharides (Fn-type inulin) resulting from the endo-inulinase hydrolysis of globe artichoke inulin were purified and characterized. The aim was to produce Fn oligomer standards with the intention of identifying them in the complex inulin chromatogram. Inulin was extracted from globe artichoke and presented a high average degree of polymerization (DP) of about 80 as determined by high-performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). This inulin was hydrolyzed by a commercial endo-inulinase yielding a product with a very high Fn/GFn molecule ratio, thus limiting the interference of GFn during the purification process. High-performance size exclusion chromatography was used to individually isolate and collect each retention peak corresponding to a specific oligomer. The purity of these fractions was checked by HPAEC-PAD and showed that relatively pure molecules were produced. Electrospray ionization mass spectrometry allowed the molecular weight determination of these purified oligomers and ascertained their DP as F2, F3 and F4. These F2-4 standards were used with glucose, fructose, sucrose and GF2-4 (commercially available) to spike commercial oligofructose products in order to determine the elution profile in the HPAEC-PAD chromatogram. 相似文献
9.
The equationbelongs to the class of linear functional equations. The solutions form a linear space with respect to the usual pointwise operations. According to the classical results of the theory they must be generalized polynomials. New investigations have been started a few years ago. They clarified that the existence of non-trivial solutions depends on the algebraic properties of some related families of parameters. The problem is to find the necessary and sufficient conditions for the existence of non-trivial solutions in terms of these kinds of properties. One of the earliest results is due to Z. Daróczy [1]. It can be considered as the solution of the problem in case of n = 2. We are going to take more steps forward by solving the problem in case of n = 3.
相似文献
$$\sum^{n}_ {i=0} a_{i}f(b_{i}x + (1 - b_{i})y) = 0$$
10.
The behaviour ofS-matrix for potentials generating bound states in continuum in the neighbourhood of the positive bound state energies is studied.
It is shown that unlike the case of usual negative energy bound states, theS-matrix does not have a pole at the positive bound state energy but becomes unity at the energy corresponding to bound states
in continuum. Calculations ofS-waveS-matrix for a local potential constructed by Stillinger and Herrick and a separable nonlocal potential constructed by the
present authors verify these results. Our results indicate that the bound states embedded in continuum constructedvia the von Neumann and Wigner procedure cannot be interpreted as resonances with zero width. 相似文献