46 research outputs found
Coherent vibrations of submicron spherical gold shells in a photonic crystal
Coherent acoustic radial oscillations of thin spherical gold shells of
submicron diameter excited by an ultrashort optical pulse are observed in the
form of pronounced modulations of the transient reflectivity on a subnanosecond
time scale. Strong acousto-optical coupling in a photonic crystal enhances the
modulation of the transient reflectivity up to 4%. The frequency of these
oscillations is demonstrated to be in good agreement with Lamb theory of free
gold shells.Comment: Error in Eqs.2 and 3 corrected; Tabl. I corrected; Fig.1 revised; a
model that explains the dependence of the oscillation amplitude of the
transient reflectivity with wavelength adde
Π ΡΠΈΠ½Π°Π½ΡΠΎΠ²ΠΎ-ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΎΠΌ ΠΊΡΠΈΠ·ΠΈΡΠ΅
Π£ ΡΡΠ°ΡΡΡ Π΄Π»Ρ Π²ΠΈΠ·Π½Π°ΡΠ΅Π½Π½Ρ ΠΏΠΎΠ·ΠΈΡΡΡ ΠΌΠΎΠ»ΠΎΠ΄ΠΈΡ
ΡΡΠ΅Π½ΠΈΡ
, ΡΡΠΎΡΠΎΠ²Π½ΠΎ ΡΡΠ½Π°Π½ΡΠΎΠ²ΠΎ-Π΅ΠΊΠΎΠ½ΠΎΠΌΡΡΠ½ΠΎΡ ΠΊΡΠΈΠ·ΠΈ 2008β2010 Ρ. Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½ΠΈΠΉ ΠΌΠ΅ΡΠΎΠ΄ Π½Π΅ΡΡΡΠΊΠΎΡ ΠΊΠ»Π°ΡΡΠ΅ΡΠΈΠ·Π°ΡΡΡ Π΄Π°Π½ΠΈΡ
, ΡΠΎ ΠΏΡΠ°ΡΡΡ Π² ΡΠ΅ΠΆΠΈΠΌΡ ΠΏΠ°ΡΠ°Π»Π΅Π»ΡΠ½ΠΎΡ ΡΡ
Π½ΡΠΎΡ ΠΎΠ±ΡΠΎΠ±ΠΊΠΈ. ΠΠ°Π²Π΅Π΄Π΅Π½ΠΎ Π·Π°Ρ
ΠΎΠ΄ΠΈ ΡΠΎΠ΄ΠΎ Π·Π½ΠΈΠΆΠ΅Π½Π½Ρ Π½Π°ΡΠ»ΡΠ΄ΠΊΡΠ² ΠΊΡΠΈΠ·ΠΈ Π΄Π»Ρ Π£ΠΊΡΠ°ΡΠ½ΠΈ.Π ΡΡΠ°ΡΡΠ΅ Π΄Π»Ρ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΏΠΎΠ·ΠΈΡΠΈΠΈ ΠΌΠΎΠ»ΠΎΠ΄ΡΡ
ΡΡΠ΅Π½ΡΡ
, ΠΏΡΠΈΠΌΠ΅Π½ΠΈΡΠ΅Π»ΡΠ½ΠΎ ΠΊ ΡΠΈΠ½Π°Π½ΡΠΎΠ²ΠΎ-ΡΠΊΠΎΠ½ΠΎΠΌΠΈΡΠ΅ΡΠΊΠΎΠΌΡ ΠΊΡΠΈΠ·ΠΈΡΡ 2008β2010 Π³Π³. ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ ΠΌΠ΅ΡΠΎΠ΄ Π½Π΅ΡΠ΅ΡΠΊΠΎΠΉ ΠΊΠ»Π°ΡΡΠ΅ΡΠΈΠ·Π°ΡΠΈΠΈ Π΄Π°Π½Π½ΡΡ
, ΠΊΠΎΡΠΎΡΡΠΉ ΡΠ°Π±ΠΎΡΠ°Π΅Ρ Π² ΡΠ΅ΠΆΠΈΠΌΠ΅ ΠΏΠ°ΡΠ°Π»Π»Π΅Π»ΡΠ½ΠΎΠΉ ΠΈΡ
ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ. ΠΡΠΈΠ²Π΅Π΄Π΅Π½Ρ ΠΌΠ΅ΡΠΎΠΏΡΠΈΡΡΠΈΡ ΠΏΠΎ ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΡ ΠΏΠΎΡΠ»Π΅Π΄ΡΡΠ²ΠΈΠΉ ΠΊΡΠΈΠ·ΠΈΡΠ° Π΄Π»Ρ Π£ΠΊΡΠ°ΠΈΠ½Ρ.In an article for determining the position of young scientists, in relation to financial and economic crisis, 2008β 2010. used the method of fuzzy clustering, which operates in parallel processing. Shows the measures to reduce the impact of the crisis in Ukraine
Goal-recognition-based adaptive brain-computer interface for navigating immersive robotic systems
Β© 2017 IOP Publishing Ltd. Objective. This work proposes principled strategies for self-adaptations in EEG-based Brain-computer interfaces (BCIs) as a way out of the bandwidth bottleneck resulting from the considerable mismatch between the low-bandwidth interface and the bandwidth-hungry application, and a way to enable fluent and intuitive interaction in embodiment systems. The main focus is laid upon inferring the hidden target goals of users while navigating in a remote environment as a basis for possible adaptations. Approach. To reason about possible user goals, a general user-agnostic Bayesian update rule is devised to be recursively applied upon the arrival of evidences, i.e. user input and user gaze. Experiments were conducted with healthy subjects within robotic embodiment settings to evaluate the proposed method. These experiments varied along three factors: the type of the robot/environment (simulated and physical), the type of the interface (keyboard or BCI), and the way goal recognition (GR) is used to guide a simple shared control (SC) driving scheme. Main results. Our results show that the proposed GR algorithm is able to track and infer the hidden user goals with relatively high precision and recall. Further, the realized SC driving scheme benefits from the output of the GR system and is able to reduce the user effort needed to accomplish the assigned tasks. Despite the fact that the BCI requires higher effort compared to the keyboard conditions, most subjects were able to complete the assigned tasks, and the proposed GR system is additionally shown able to handle the uncertainty in user input during SSVEP-based interaction. The SC application of the belief vector indicates that the benefits of the GR module are more pronounced for BCIs, compared to the keyboard interface. Significance. Being based on intuitive heuristics that model the behavior of the general population during the execution of navigation tasks, the proposed GR method can be used without prior tuning for the individual users. The proposed methods can be easily integrated in devising more advanced SC schemes and/or strategies for automatic BCI self-adaptations
Rotational averaging-out gravitational sedimentation of colloidal dispersions and phenomena
We report on the differences between colloidal systems left to evolve in the
earth's gravitational field and the same systems for which a slow continuous
rotation averaged out the effects of particle sedimentation on a distance scale
small compared to the particle size. Several systems of micron-sized colloidal
particles were studied: a hard sphere fluid, colloids interacting via
long-range electrostatic repulsions above the freezing volume fraction, an
oppositely charged colloidal system close to either gelation and/or
crystallization, colloids with a competing short-range depletion attraction and
a long-range electrostatic repulsion, colloidal dipolar chains, and colloidal
gold platelets under conditions where they formed stacks. Important differences
in the structure formation were observed between the experiments where the
particles were allowed to sediment and those where sedimentation was averaged
out. For instance, in the case of colloids interacting via long-range
electrostatic repulsions, an unusual sequence of
dilute-Fluid/dilute-Crystal/dense-Fluid/dense-Crystal phases was observed
throughout the suspension under the effect of gravity, related to the volume
fraction dependence of the colloidal interactions, whereas the system stayed
homogeneously crystallized with rotation. For the oppositely charged colloids,
a gel-like structure was found to collapse under the influence of gravity with
a few crystalline layers grown on top of the sediment, whereas when the
colloidal sedimentation was averaged out, the gel completely transformed into
crystallites that were oriented randomly throughout the sample. Rotational
averaging out gravitational sedimentation is an effective and cheap way to
estimate the importance of gravity for colloidal self-assembly processes.Comment: 13 pages, 13 figure