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211.
The content of total polyphenols, flavonoids and coumarins in the aerial parts of pineapple weed (Chamomilla suaveolens (Pursh) Rydb.), growing wild in Estonia, was determined chromato-spectrophotometrically, and individual polyphenols were quantified using HPLC-DAD-MS/MS. The total content of polyphenols was rather similar in flowers (9.1-11.5%) and in whole aerial parts (8.4-10.9%) of pineapple weed. The upper one-third (1/3) and upper two-thirds (2/3) of the aerial parts contained more flavonoids (0.15 - 0.20%) than the flowers (0.12%). The content of coumarins showed no significant difference between the flowers and the upper 1/3 and 2/3 of the aerial parts. The main polyphenols in the flowers were dicaffeoylquinic acids (202-380 mkg/mL), chlorogenic acids (75-185 mkg/mL), and ferulic acid glycoside (61-124 mkg/mL). Also found were quercetin galactoside, apigenin acetylglucoside, malonylapigenin glucoside, as well as luteolin, quercetin and apigenin glycosides. 相似文献
212.
Hermi F. Brito Jukka Hassinen Jorma Hölsä Högne Jungner Taneli Laamanen Mika Lastusaari Marja Malkamäki Janne Niittykoski Pavel Novák Lucas C. V. Rodrigues 《Journal of Thermal Analysis and Calorimetry》2011,105(2):657-662
The details of the mechanism of persistent luminescence were probed by investigating the trap level structure of Sr2MgSi2O7:Eu2+,R3+ materials (R: Y, La-Lu, excluding Pm and Eu) with thermoluminescence (TL) measurements and Density Functional Theory (DFT)
calculations. The TL results indicated that the shallowest traps for each Sr2MgSi2O7:Eu2+,R3+ material above room temperature were always ca. 0.7 eV corresponding to a strong TL maximum at ca. 90 °C. This main trap
energy was only slightly modified by the different co-dopants, which, in contrast, had a significant effect on the depths
of the deeper traps. The combined results of the trap level energies obtained from the experimental data and DFT calculations
suggest that the main trap responsible for the persistent luminescence of the Sr2MgSi2O7:Eu2+,R3+ materials is created by charge compensation lattice defects, identified tentatively as oxygen vacancies, induced by the R3+ co-dopants. 相似文献
213.
Halme J 《Physical chemistry chemical physics : PCCP》2011,13(27):12435-12446
This paper unifies the analytical models used widely but thus far mostly separately for electrical and optical small amplitude perturbation measurements of nanostructured electrochemical dye solar cells (DSC): electrochemical impedance spectroscopy (EIS), intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated photovoltage spectroscopy (IMVS). The models are linked by expressing the kinetic boundary condition used for solving the time-dependent continuity equation of electrons in IMPS and IMVS analysis in terms of the series and parallel impedance components found in the complete equivalent circuit impedance model of DSC. As a result, analytical expressions are derived for potentiostatic IMPS and galvanostatic IMVS transfer functions of complete DSCs that are applicable at any operating point along the solar cell current-voltage (IV) curve. In agreement with the theory, impedance spectrum calculated as a ratio of IMVS and IMPS transfer functions measured near the maximum power point matches exactly with the impedance spectrum measured directly with EIS. Consequently, both IMPS-IMVS and EIS yield equal estimates for the electron diffusion length. The role of the chemical capacitance of the nanostructured semiconductor photoelectrode in the interpretation of the so-called RC attenuation of the IMPS response is clarified, as well as the capacitive frequency dispersion in IMPS and IMVS. 相似文献
214.
Janne Gröhn 《Bulletin des Sciences Mathématiques》2011,(5):475
The iterative method of successive approximations, originally introduced by Émile Picard in 1890, is a basic tool for proving the existence of solutions of initial value problems regarding ordinary first order differential equations. In the present paper, it is shown that this method can be modified to get estimates for the growth of solutions of linear differential equations of the typef(k)+Ak−1(z)f(k−1)+?+A1(z)f′+A0(z)f=0 with analytic coefficients. A short comparison to the growth results in the literature, obtained by means of different methods, is also given. It turns out that many known results can be proved by applying Picard?s successive approximations in an effective way. Self-contained considerations are carried out in the complex plane and in the unit disc, and some remarks about solutions of real linear differential equations are made. 相似文献
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219.
Jarkko J. Saarinen Dimitar Valtakari Janne Haapanen Turkka Salminen Jyrki M. Mäkelä Jun Uozumi 《Optical Review》2014,21(3):339-344
Surface-enhanced Raman scattering (SERS) active substrates were made via liquid flame spray deposition and inkjet printing of silver nanoparticles. Both processes are suitable for cost-effective fabrication of large-area SERS substrates. Crystal violet (CV) solutions were used as target molecules and in both samples the detection limit was approximately 10 nM. In addition, sintering temperature of the inkjet printed silver nanoparticles was found to have a large effect on the SERS activity with the higher curing temperature of 200 °C resulting in contamination layer on silver and cancelation of the SERS signal. This layer was characterized using an X-ray photoelectron spectroscopy (XPS). 相似文献
220.
On a fixed Riemann surface (M 0, g 0) with N Euclidean ends and genus g, we show that, under a topological condition, the scattering matrix S V (λ) at frequency λ > 0 for the operator Δ+V determines the potential V if \({V\in C^{1,\alpha}(M_0)\cap e^{-\gamma d(\cdot,z_0)^j}L^\infty(M_0)}\) for all γ > 0 and for some \({j\in\{1,2\}}\) , where d(z, z 0) denotes the distance from z to a fixed point \({z_0\in M_0}\) . The topological condition is given by \({N\geq \max(2g+1,2)}\) for j = 1 and by N ≥ g + 1 if j = 2. In \({\mathbb {R}^2}\) this implies that the operator S V (λ) determines any C 1, α potential V such that \({V(z)=O(e^{-\gamma|z|^2})}\) for all γ > 0. 相似文献