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131.
Ayodele Oladeji Lukasz Sojka Zhuoqi Tang David Furniss Andrew Phillips Angela Seddon Trevor Benson Slawomir Sujecki 《Optical and Quantum Electronics》2014,46(4):593-602
The experimentally obtained luminescence characteristics of a praseodymium (Pr $^{3+})$ doped chalcogenide glass fiber are studied numerically using a rate equation approach. The numerical model includes both the radiative and non-radiative transition paths whilst it neglects the up-conversion processes. Photoluminescence spectra at mid-infrared wavelengths ranging from 3.5 to 6 ${\upmu }$ m were obtained by using two pump wavelengths: 1.55 and 1.94 ${\upmu }$ m. A good agreement between the experiment and theory is obtained for the photoluminescence decay profiles. 相似文献
132.
Prof. Danuta Kruk Dr. Pawel Rochowski Dr. Elzbieta Masiewicz Dr. Slawomir Wilczynski Milosz Wojciechowski Dr. Lionel M. Broche Prof. David J. Lurie 《Chemphyschem》2019,20(21):2816-2822
1H spin−lattice nuclear magnetic resonance relaxation experiments were performed for five kinds of dermal fillers based on hyaluronic acid. The relaxation data were collected over a broad frequency range between 4 kHz and 40 MHz, at body temperature. Thanks to the frequency range encompassing four orders of magnitude, the dynamics of water confined in the polymeric matrix was revealed. It is demonstrated that translation diffusion of the confined water molecules exhibits a two-dimensional character and the diffusion process is slower than diffusion in bulk water by 3–4 orders of magnitude. As far as rotational dynamics of the confined water is concerned, it is shown that in all cases there is a water pool characterized by a rotational correlation time of about 4×10−9 s. In some of the dermal fillers a fraction of the confined water (about 10 %) forms a pool that exhibits considerably slower (by an order of magnitude) rotational dynamics. In addition, the water binding capacity of the dermal fillers was quantitatively compared. 相似文献
133.
Grzegorz Leniec Tomasz Skibiński Slawomir M. Kaczmarek Przemyslaw Iwanowski Marek Berkowski 《Central European Journal of Physics》2012,10(2):500-505
Growth conditions and electron paramagnetic resonance investigations of two well oriented KSm(WO4)2 and KEr(WO4)2 single crystals have been presented and discussed. Hyperfine structure of Sm3+ ion was detected and analyzed for angular and temperature dependences. EPR spectra of KEr(WO4)2 and its angular dependence showed the presence of 5 magnetically nonequivalent Er centers in the crystal. A change in the
type of magnetic interactions was analyzed using mixed (Gaussian and Lorentzian) fits of the EPR spectra. 相似文献
134.
Slawomir M. Kaczmarek Lucyna Macalik Hubert Fuks Grzegorz Leniec Tomasz Skibiński Jerzy Hanuza 《Central European Journal of Physics》2012,10(2):492-499
Well oriented KYb(WO4)2 and KTb0.2Yb0.8(WO4)2 single crystals have been investigated for their magnetic and optical properties using the Raman and EPR techniques. The
registered EPR signal is dominated by three lines ascribed to ytterbium ions: one main and two satellites. Tb ions, although
non-paramagnetic, distinctly modify magnetic properties of the KYb(WO4)2 single crystal. Basic parameters of the spin Hamiltonian, including Zeeman and hyperfine terms (g and A matrices) as well the spatial orientation between principal and crystallographic axes systems were determined for both crystals. 相似文献
135.
Slawomir Rubinsztajn Julian Chojnowski Marek Cypryk Urszula Mizerska Pawel Uznański Agnieszka Walkiewicz-Pietrzykowska 《应用有机金属化学》2020,34(5):e5571
Reactions of titanium tetrabutoxide with polyhydromethylsiloxane (PHMS) and with some hydromethylsiloxane copolymers were used for synthesis of light transparent materials having enhanced refractive index. The FTIR, 1H NMR and 29Si NMR spectroscopies were used to study the reaction between PHMS and titanium tetrabutoxide in toluene. Reaction of SiH functional siloxane polymers with titanium tetrabutoxide results in a titanium-containing heterosiloxane prepolymers that are stable under anhydrous anaerobic conditions. Exposure of the resulting materials to humid air transforms them into light transparent titanium/siloxane nanocomposites with enhanced refractive index. The films of these composites formed during the spin-coating process were characterized by UV–Vis, ellipsometry, IR and 29Si NMR spectroscopies and transmission electron microscopy (TEM). Titanium/siloxane hybrid films obtained on the basis of poly(phenylmethylsiloxane-co-hydromethylsiloxane) copolymer are free of cracks and have a refractive index of up to 1.60. 相似文献
136.
137.
Structural Chemistry - Topological analysis of the electron localisation function (ELF), natural bond orbital and Wiberg bond index calculations have been applied to study the electronic structure... 相似文献
138.
Tomasz Bodziony Slawomir M. Kaczmarek Czeslaw Rudowicz 《Physica B: Condensed Matter》2008,403(1):207-218
The electron paramagnetic resonance (EPR) studies of LiNbO3 single crystal doped with 1 wt% of Yb3+ are reported. To put the EPR results in perspective, a brief discussion of optical absorption spectroscopy investigations of LiNbO3:Yb3+ is provided. The temperature behavior of the EPR lines intensity and linewidth for LiNbO3:Yb3+ reveals antiferromagnetic coupling between Yb3+ ions. The deconvolution of the EPR lines indicates that EPR signals arise from both the isolated Yb3+ ions as well as the Yb3+-Yb3+ ion pairs; the latter signals dominate. Based on this indication, EPR spectra are interpreted using a spin Hamiltonian for the Yb3+ dissimilar ion pairs. The negative sign of the isotropic parameter J confirms the existence of the antiferromagnetic interactions within Yb3+-Yb3+ pairs. The value of J obtained based on the proposed pair model, assuming the dipole-dipole interactions, is used to identify the positions of the Yb3+-Yb3+ pairs in the unit cell. Our results suggest the evenYb3+-evenYb3+ pairs are located at the neighboring Li+ and Nb5+ positions, whereas the pair axis is not parallel to the optical c-axis. Some alternative explanations of the observed EPR spectra are also considered. 相似文献
139.
Pekka J. Lahti Slawomir Bugajski 《International Journal of Theoretical Physics》1985,24(11):1051-1080
Some classical and quantum theories are characterized within the convexity approach to probabilistic physical theories. In particular, the structure of the so-called DHB quantum theory will be analyzed. It turns out that the natural generalization of the standard Hubert space quantum mechanics, the operational one, is such a theory. The operational Hilbert space quantum theory will be reconstructed from the (weak) projection postulate and the complementarity principle. This is then used to argue that the DHB quantum theory is identical with the operational Hilbert space quantum theory. 相似文献
140.
Arthur Jaffe Slawomir Klimek Andrzej Lesniewski 《Communications in Mathematical Physics》1989,126(2):421-431
We formulate reflection positivity for meromorphic functions and for 1-forms on a Riemann surface. This construction yields representations of the Heisenberg algebra on a Riemann surface.Supported in part by the Department of Energy under Grant DE-FG02-88ER25065 相似文献