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71.
72.
Bilender P. Allahverdiev 《Mathematical Methods in the Applied Sciences》2019,42(1):229-236
In this study, maximal dissipative second‐order dynamic operators on semi‐infinite time scale are studied in the Hilbert space , that the extensions of a minimal symmetric operator in limit‐point case. We construct a self‐adjoint dilation of the dissipative operator together with its incoming and outgoing spectral representations so that we can determine the scattering function of the dilation as stated in the scheme of Lax‐Phillips. Moreover, we construct a functional model of the dissipative operator and identify its characteristic function in terms of the Weyl‐Titchmarsh function of a self‐adjoint second‐order dynamic operator. Finally, we prove the theorems on completeness of the system of root functions of the dissipative and accumulative dynamic operators. 相似文献
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In this paper, we study the commutativity of Toeplitz operators with radial symbols on the pluriharmonic Bergman space. We obtain the necessary and sufficient conditions for the commutativity of bounded Toeplitz operator and Toeplitz operator with radial symbol on the pluriharmonic Bergman space. 相似文献
77.
Inês C. Santos Raquel B.R. Mesquita Ana Machado Adriano A. Bordalo António O.S.S. Rangel 《Analytica chimica acta》2013
A sequential injection method (SIA) for carbon speciation in inland bathing waters was developed comprising, in a single manifold, the determination of dissolved inorganic carbon (DIC), free dissolved carbon dioxide (CO2), total carbon (TC), dissolved organic carbon and alkalinity. The determination of DIC, CO2 and TC was based on colour change of bromothymol blue (660 nm) after CO2 diffusion through a hydrophobic membrane placed in a gas diffusion unit (GDU). For the DIC determination, an in-line acidification prior to the GDU was performed and, for the TC determination, an in-line UV photo-oxidation of the sample prior to GDU ensured the conversion of all carbon forms into CO2. Dissolved organic carbon (DOC) was determined by subtracting the obtained DIC value from the TC obtained value. The determination of alkalinity was based on the spectrophotometric measurement of bromocresol green colour change (611 nm) after reaction with acetic acid. The developed SIA method enabled the determination of DIC (0.24–3.5 mg C L−1), CO2 (1.0–10 mg C L−1), TC (0.50–4.0 mg C L−1) and alkalinity (1.2–4.7 mg C L−1 and 4.7–19 mg C L−1) with limits of detection of: 9.5 μg C L−1, 20 μg C L−1, 0.21 mg C L−1, 0.32 mg C L−1, respectively. The SIA system was effectively applied to inland bathing waters and the results showed good agreement with reference procedures. 相似文献
78.
Lorilee S.L. Arakaki Kenneth A. Schenkman Wayne A. Ciesielski Jeremy M. Shaver 《Analytica chimica acta》2013
We have developed a method to make real-time, continuous, noninvasive measurements of muscle oxygenation (Mox) from the surface of the skin. A key development was measurement in both the visible and near infrared (NIR) regions. Measurement of both oxygenated and deoxygenated myoglobin and hemoglobin resulted in a more accurate measurement of Mox than could be achieved with measurement of only the deoxygenated components, as in traditional near-infrared spectroscopy (NIRS). Using the second derivative with respect to wavelength reduced the effects of scattering on the spectra and also made oxygenated and deoxygenated forms more distinguishable from each other. Selecting spectral bands where oxygenated and deoxygenated forms absorb filtered out noise and spectral features unrelated to Mox. NIR and visible bands were scaled relative to each other in order to correct for errors introduced by normalization. Multivariate Curve Resolution (MCR) was used to estimate Mox from spectra within each data set collected from healthy subjects. A Locally Weighted Regression (LWR) model was built from calibration set spectra and associated Mox values from 20 subjects using 2562 spectra. LWR and Partial Least Squares (PLS) allow accurate measurement of Mox despite variations in skin pigment or fat layer thickness in different subjects. The method estimated Mox in five healthy subjects with an RMSE of 5.4%. 相似文献
79.
D. Haristoy S. Mery B. Heinrich L. Mager J. F. Nicoud D. Guillon 《Liquid crystals》2013,40(3):321-328
A series of [1]benzothieno[3,2-b][1]benzothiophene-2,7-dicarboxylate derivatives consisting of a flat, conjugated aromatic moiety containing sulphur hetero-atoms and substituted by terminal chains - ethyl, decyl, Z-4-decenyl or 2-(2-butoxyethoxy)ethyl - has been synthesized. These materials exhibit a smectic liquid crystalline phase, the stability of which was found to be strongly dependent on the length and the nature of the terminal chains. In the mesophase, the molecular arrangement within the smectic layer is characterized by a local stacking of the rigid parts similar to that found in discotic columnar systems. Finally, clear photoconductive behaviour was found in mechanically aligned samples of these liquid crystals. 相似文献
80.
Chiral monomer (M1 ), mesogenic and non-mesogenic crosslinking agents (C1 and C2 ), and the corresponding liquid crystalline elastomers (P1 and P2 series), have been synthesised. Their chemical structures have been characterised by Fourier transform infrared or 1H nuclear magnetic resonance and their phase behaviour investigated by differential scanning calorimetry, polarising optical miscoscopy, thermo-gravimetric analysis (TGA) and X-ray diffraction. The effect of the crosslinking unit on the phase behaviour of the elastomers has been studied. M1 showed a cholesteric oily streak and focal conic texture. C2 exhibited a nematic enantiotropic thread-like and schlieren texture, and a monotropic fan-shaped texture in the SA phase. Due to the introduction of the mesogenic crosslinking unit, elastomers, P2-1 ?P2-5 , exhibited a cholesteric phase, while elastomers, P1-1 ?P1-4 , derived from a non-mesogenic crosslinking unit, exhibit a SA phase. As the content of the crosslinking unit increased, the T g of the P1 series initially decreased and then increased, and the T i of the series decreased. In the P2 series the T g increased, but the T i initially increased and then decreased. TGA confirmed that all the elastomers had improved thermal stability. 相似文献