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391.
Controlling the spontaneous emission rate of single quantum dots in a two-dimensional photonic crystal 总被引:1,自引:0,他引:1
Englund D Fattal D Waks E Solomon G Zhang B Nakaoka T Arakawa Y Yamamoto Y Vucković J 《Physical review letters》2005,95(1):013904
We observe large spontaneous emission rate modification of individual InAs quantum dots (QDs) in a 2D photonic crystal with a modified, high-Q single-defect cavity. Compared to QDs in a bulk semiconductor, QDs that are resonant with the cavity show an emission rate increase of up to a factor of 8. In contrast, off-resonant QDs indicate up to fivefold rate quenching as the local density of optical states is diminished in the photonic crystal. In both cases, we demonstrate photon antibunching, showing that the structure represents an on-demand single photon source with a pulse duration from 210 ps to 8 ns. We explain the suppression of QD emission rate using finite difference time domain simulations and find good agreement with experiment. 相似文献
392.
Ristić J Calleja E Trampert A Fernández-Garrido S Rivera C Jahn U Ploog KH 《Physical review letters》2005,94(14):146102
Self-assembled columnar AlGaN/GaN nanocavities, with an active region of GaN quantum disks embedded in an AlGaN nanocolumn and cladded by top and bottom AlN/GaN Bragg mirrors, were grown. The nanocavity has no cracks or extended defects, due to the relaxation at the Si interface and to the nanocolumn free-surface to volume ratio. The emission from the active region matched the peak reflectivity by tuning the Al content and the GaN disks thickness. Quantum confinement effects that depend on both the disk thickness and the inhomogeneous strain distribution within the disks are clearly observed. 相似文献
393.
Jelena Vidakovic Mihailo Lazarevic Vladimir Kvrgic Zorana Dančuo Maja Lutovac 《PAMM》2013,13(1):485-486
To achieve predefined Gz load profile in high G training in human centrifuge, it is necessary to determine angular velocity and acceleration of a planetary axis (centrifuge arm). Initial value problem that can not be solved in closed form was obtained. Several discretization methods for calculating angular velocity of centrifuge arm driven by DC servo motor are presented. Simulations are performed for different positive and negative values of Gz onset. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
394.
We study the asymptotic behavior of solutions of the odd-order differential equation of Emden–Fowler type $$ {x^{{\left( {2n+1} \right)}}}(t)=q(t){{\left| {x(t)} \right|}^{\gamma }}\operatorname{sgn}x(t) $$ in the framework of regular variation under the assumptions that 0 < γ < 1 and q(t) : [a, ∞) → (0, ∞) is regularly varying function. We show that complete and accurate information can be acquired about the existence of all possible positive solutions and their asymptotic behavior at infinity. 相似文献
395.
Jaroslav Jaroš Kusano Takaŝi Jelena Manojlović 《Central European Journal of Mathematics》2013,11(12):2215-2233
Positive solutions of the nonlinear second-order differential equation $(p(t)|x'|^{\alpha - 1} x')' + q(t)|x|^{\beta - 1} x = 0,\alpha > \beta > 0,$ are studied under the assumption that p, q are generalized regularly varying functions. An application of the theory of regular variation gives the possibility of obtaining necessary and sufficient conditions for existence of three possible types of intermediate solutions, together with the precise information about asymptotic behavior at infinity of all solutions belonging to each type of solution classes. 相似文献
396.
Kalnina I Zvagule T Gabruseva N Kirilova J Kurjane N Bruvere R Kesters A Kizane G Kirilovs G Meirovics I 《Journal of fluorescence》2007,17(6):633-638
ABM (3-aminobenzanthrrone derivative) developed at the Riga Technical University, Riga, Latvia) has been previously shown
as a potential probe for determination of the immune state of patients with different pathologies .The fist study (using probe
ABM) of peripheral blood mononuclear cells (PBMC) membranes of 97 Chernobyl clean-up workers from Latvia was conducted in
1997. Now we repeatedly examine the same (n = 54) individuals in dynamics. ABM spectral parameters in PBMC suspension, fluorescence
anisotropy and blood plasma albumin characteristics were recorded. In 1997 screening showed 5 different patterns of fluorescence
spectra, from which in 2007 we obtained only two. These patterns of spectra had never been previously seen in healthy individuals
or patients with tuberculosis, multiple sclerosis, rheumatoid arthritis, etc., examined by us. Patterns of ABM fluorescence
spectra are associated with membrane anisotropy and conformational changes of blood plasma albumin. We observed that in dynamics
1997–2007 the lipid compartment of the membrane became more fluid while the lipid-protein interface became more rigid. The
use of probe ANS and albumin auto-fluorescence allowed show conformational alterations in Chernobyl clean-up workers blood
plasma. It is necessary to note that all investigated parameters significantly differ in observed groups of patients. These
findings reinforce our understanding that that the cell membrane is a significant biological target of radiation. The role
of the membrane in the expression and course of cell damage after radiation exposure must be considered. So ten years dynamic
of PBMC membrane characteristics by ABM (spectral shift and anisotropy indexes) in Chernobyl clean-up workers reveal progressive
trend toward certain resemblance with those of chronic B-cell lymphoid leukemia. 相似文献
397.
Fidanchevski Emilija Angjusheva Biljana Jovanov Vojo Murtanovski Pece Vladiceska Ljubica Aluloska Nikolina Stamatovska Nikolic Jelena Krneta Ipavec Andrej Šter Katarina Mrak Maruša Dolenec Sabina 《Journal of Radioanalytical and Nuclear Chemistry》2021,330(3):685-694
Journal of Radioanalytical and Nuclear Chemistry - Huge quantities of fly ash and bottom ash are generated from thermal power plants and it presents great concern for country, mainly due... 相似文献
398.
Rowe L Almasri M Lee K Fogleman N Brewer GJ Nam Y Wheeler BC Vukasinovic J Glezer A Frazier AB 《Lab on a chip》2007,7(4):475-482
This work demonstrated the design, fabrication, packaging, and characterization of an active microscaffold system with fluid perfusion/nutrient delivery functionalities for culturing in vitro neuronal networks from dissociated hippocampal rat pup neurons. The active microscaffold consisted of an 8 x 8 array of hollow, microfabricated, SU-8 towers (1.0 mm or 1.5 mm in height), with integrated, horizontal, SU-8 cross-members that connect adjacent towers, thus forming a 3-D grid that is conducive to branching, growth, and increased network formation of dissociated hippocampal neurons. Each microtower in the microscaffold system contained a hollow channel and multiple fluid ports for media delivery and perfusion of nutrients to the in vitro neuronal network growing within the microscaffold system. Additionally, there were two exposed Au electrodes on the outer wall of each microtower at varying heights (with insulated leads running within the microtower walls), which will later allow for integration of electrical stimulation/recording functionalities into the active microscaffold system. However, characterization of the stimulation/recording electrodes was not included in the scope of this paper. Design, fabrication, fluid packaging, and characterization of the active microscaffold system were performed. Furthermore, use of the active microscaffold system was demonstrated by culturing primary hippocampal embryonic rat pup neurons, and characterizing cell viability within the microscaffold system. 相似文献
399.
400.
Benndorf P Jenter J Zielke L Roesky PW 《Chemical communications (Cambridge, England)》2011,47(9):2574-2576
Enantiomerically pure lutetium complexes were synthesized as the first rare earth metal complexes containing a chiral amidinate ligand. The catalytic activity and the enantioselectivity in hydroamination reactions were studied. 相似文献