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1.
The Sm3+ ion in the Cs2NaYF6 single crystal was studied by optically detected electron paramagnetic resonance spectroscopy. Magnetic resonance signals
were recorded by Faraday rotation at the frequency of 0.6–0.85 GHz and magnetic fields of about 0.14 T. The hyperfine parameters
of 147Sm3+ and 149Sm3+ isotopes were determined. 相似文献
2.
A survey of retrial queues 总被引:18,自引:0,他引:18
Gennadij Falin 《Queueing Systems》1990,7(2):127-167
We present a survey of the main results and methods of the theory of retrial queues, concentrating on Markovian single and multi-channel systems. For the single channel case we consider the main model as well as models with batch arrivals, multiclasses, customer impatience, double connection, control devices, two-way communication and buffer. The stochastic processes arising from these models are considered in the stationary as well as the nonstationary regime. For multi-channel queues we survey numerical investigations of stationary distributions, limit theorems for high and low retrial intensities and heavy and light traffic behaviour. 相似文献
3.
In modern telephone exchanges, subscriber lines are usually connected to the so-called subscriber line modules. These modules serve both incoming and outgoing traffic. An important difference between these two types of calls lies in the fact that in the case of blocking due to all channels busy in the module, outgoing calls can be queued whereas incoming calls get busy signal and must be re-initiated in order to establish the required connection. The corresponding queueing model was discussed recently by Lederman, but only the model with losses has been studied analytically. In the present contribution, we study the model which takes into account subscriber retrials and investigate some of its properties such as existence of stationary regime, derive explicit formulas for the system characteristics, limit theorems for systems under high repetition intensity of blocked calls and limit theorems for systems under heavy traffic. 相似文献
4.
ENDOR measurements on the19F? nuclei in the first four shells of KZnF3 containing Dy3+ ions in the cubic site are reported. The values and signs of the hyperfine and transferred hyperfine interaction parameters are determined. The local deformation of the crystal lattice in the vicinity of the impurity ion is estimated. The theoretical analysis of the THFI parameters for the first coordination shell of the F? ions has been carried out. For the Dy3+ ion the influence of spin polarization of the closed 5s and 5p shells is considered for the first time. Spin polarization is shown to play a significant role in the mechanisms of rare-earth ion-ligand coupling. 相似文献
5.
G. I. Falin 《Mathematical Notes》1988,44(2):606-608
6.
7.
Motiei L Altman M Gupta T Lupo F Gulino A Evmenenko G Dutta P van der Boom ME 《Journal of the American Chemical Society》2008,130(28):8913-8915
Accelerated growth of a molecular-based material that is an active participant in its continuing self-propagated assembly has been demonstrated. This nonlinear growth process involves diffusion of palladium into a network consisting of metal-based chromophores linked via palladium. 相似文献
8.
ABSTRACTIn this work, a coarse-grained molecular dynamics simulation method that belongs to the class of dissipative particle dynamics scheme with implicit solvent was used to indicate that adsorption of nanoparticles (NPs) inside a lipid membrane tube and pressure difference across the membrane, e.g. osmotic pressure, cooperatively induce membrane tube pearling. We demonstrate that NP adsorption and aggregation initiate the shape transformation of the lipid tube, and pressure difference provides a driving force for pearling transition. Depending on the dynamic coupling of tube shape transition and NP aggregation in the interior of the tube, different shape transitions via four kinds of pearling pathways are recognised, including pearls on a string (i.e. vesicles are interconnected via either a chain or double-chain of NPs) and tube-to-vesicle transition that is dominated kinetically either by NP-membrane attraction or by pressure difference. Considering the fact that biological membranes are semipermeable and many proteins interact with the membranes, these findings not only provide a mechanism of membrane tube pearling but also demonstrate the importance of osmotic pressure and protein–membrane interaction for many cell activities related to shape transitions of biomembrane. 相似文献
9.
Cubic paramagnetic centers formed by Yb3+ impurity ions in fluorite-type crystals MeF2 (Me = Cd, Ca, Pb) have been investigated using electron paramagnetic resonance, magnetic circular dichroism, magnetic circular polarization of luminescence, Zeeman splitting of optical absorption and luminescence lines, and optical detection of electron paramagnetic resonance. The g factors of the 2Γ7 state in the excited multiplet 2 F 5/2 of Yb3+ ions in Me F2 crystals, the hyperfine interaction constant 171 A (171Yb) for the excited multiplet 2 F 5/2 in the CaF2 crystal, and the energies and symmetry properties of all energy levels of Yb3+ ions in MeF2 crystals are determined. The crystal-field parameters for the crystals under investigation are calculated. 相似文献
10.
Facchetti A Beverina L van der Boom ME Dutta P Evmenenko G Shukla AD Stern CE Pagani GA Marks TJ 《Journal of the American Chemical Society》2006,128(6):2142-2153
The new dibranched, heterocyclic "push-pull" chromophores bis{1-(pyridin-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}methane (1), 1-(pyrid-4-yl)-2-(N-methyl-5-formylpyrrol-2-yl)ethylene (2), {1-(N-methylpyridinium-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}{(1-(pyridin-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}methane (3), N-methyl-2-[1-(N-methylpyrid-4-yl)ethen-2-yl]-5-[pyrid-4-yl]ethen-2-yl]pyrrole iodide (4), bis{1-(N-methyl-4-pyridinio)-2-[2-(N-methylpyrrol-5-yl)]ethane}methane iodide (5), and N-methyl-2,5-[1-(N-methylpyrid-4-yl)ethen-2-yl]pyrrole iodide (6) have been synthesized and characterized. The neutral (1 and 2) and monomethyl salts (3 and 4) undergo chemisorptive reaction with iodobenzyl-functionalized surfaces to afford chromophore monolayers SA-1/SA-2 and SA-3/SA-4, respectively. Molecular structures and other physicochemical properties have been defined by (1)H NMR, optical spectroscopy, and XRD. Thin-film characterization by a variety of techniques (optical spectroscopy, specular X-ray reflectivity, atomic force microscopy, X-ray photoelectron spectroscopy, and angle-dependent polarized second harmonic generation) underscore the importance of the chromophore molecular architecture as well as film growth method on film microstructure and optical/electrooptic response. 相似文献