Vortex beam carrying multiple orbital angular momentum provides a new degree of freedom to manipulate light leading to the various exciting applications as trapping, quantum optics, information multiplexing, etc. Heli...
Vortex beam carrying multiple orbital angular momentum provides a new degree of freedom to manipulate light leading to the various exciting applications as trapping, quantum optics, information multiplexing, etc. Helical wavefront can be generated either via the geometric or the dynamic phase arising from a space-variant birefringence (q-plate) or from phase accumulation through propagation (spiral-phase-plate), respectively. Using fast direct laser writing technique we fabricate and characterize novel hybrid q-plate generating vortex beam simultaneously carrying two different high-order topological charges, which arise from the spin-orbital conversion and the azimuthal height variation of the recorded structures. We approve the versatile concept to generate multiple-OAM vortex beams combining the spin-orbital interaction and the phase accumulation in a single micro-scale device, a hybrid dielectric phase plate.
Pulsed-laser fabrication of noble-metal nanorings with a tunable internal porous structure, which can be further uncapped by using an ion-beam etching procedure, was demonstrated for the first time. Density and averag...
Pulsed-laser fabrication of noble-metal nanorings with a tunable internal porous structure, which can be further uncapped by using an ion-beam etching procedure, was demonstrated for the first time. Density and average size of the pores were shown to be tuned in a wide range by varying an applied pulse energy and a chemical composition of the metal film controlled via the film magnetron deposition in the appropriate gaseous environment. According to our preliminary numerical simulations, the controlled porosity provides multifold near-field enhancement of the electromagnetic fields, making such structures promising for spectroscopic bioidentification based on a surface-enhanced Raman scattering.
In the paper an algorithm of determining the gaps in the point clouds obtained after scanning of the processed workpieces by means of vision systems is proposed. The resulting point cloud is projected on a plane, the ...
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ISBN:
(纸本)9783902734075
In the paper an algorithm of determining the gaps in the point clouds obtained after scanning of the processed workpieces by means of vision systems is proposed. The resulting point cloud is projected on a plane, the location of which is set in advance for each type of workpieces. Next, the resulting area of projection is estimated, visible points are allocated and their density on the obtained part of model is determined. In this analysis of the quality of point clouds are proposed to use of relatively simple, well-known and proven algorithms for processing of raster images. The efficiency and effectiveness of this algorithm is confirmed by a model example.
Two-layer heterostructure with GaSb nanocrystals formed by solid phase epitaxy and embedded into the silicon was investigated using low-temperature (10-140 K) photoluminescence and time-resolved photoluminescence spec...
Two-layer heterostructure with GaSb nanocrystals formed by solid phase epitaxy and embedded into the silicon was investigated using low-temperature (10-140 K) photoluminescence and time-resolved photoluminescence spectroscopies. Two characteristic luminescence bands with a maximum of about 0.82 and 0.87 eV were observed. It was found that low-energy peak is associated with D1 dislocation-related luminescence in silicon. Analysis of the decay components together with temperature and power dependencies of the photoluminescence for the high-energy maximum revealed that emission is more likely originated from the combined D2 dislocation centers in silicon and radiative recombination in type–II band alignment Si/GaSb nanocrystals/Si heterostructure. A nonradiative recombination dominates in all temperature range studied.
This paper considers a problem of fault detection, isolation and identification of its values in mechatronic systems described by nonlinear dynamic models. To solve this problem logic-dynamic approach and special feed...
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ISBN:
(纸本)9783902734075
This paper considers a problem of fault detection, isolation and identification of its values in mechatronic systems described by nonlinear dynamic models. To solve this problem logic-dynamic approach and special feedback by residual signal is suggested. This approach consists of three main steps: replacing the initial nonlinear system by certain linear logic-dynamic system, obtaining the bank of linear logic-dynamic observers, and transforming these observes into the nonlinear ones. Logic-dynamic approach allows detecting and isolating faults in nonlinear dynamic systems by using the linear methods for diagnosis in nonlinear mechatronic systems. Feedback of special form introduced in the observers after the detection and isolation of faults. It is allows to determine the value of faults even in nonlinear systems with incomplete observability. The results of mathematical simulation fully confirm the efficiency and high performance of the proposed method.
In this paper, a new approach for synthesis of the accommodation system to faults of navigation sensors of underwater vehicles(UV) is developed and investigated. Proposed system is synthesized by using kinematic model...
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In this paper, a new approach for synthesis of the accommodation system to faults of navigation sensors of underwater vehicles(UV) is developed and investigated. Proposed system is synthesized by using kinematic model of UV and data fusion of sensors signals. The results of performed simulation have completely confirmed the working capacity and high quality of the proposed approach.
During the synthesis of control systems of movement of various robotic objects (wheeled robots, unmanned aerial vehicles (UAVs), underwater robots) the dynamics of their actuators play important role. The dynamics of ...
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ISBN:
(纸本)9781479999767
During the synthesis of control systems of movement of various robotic objects (wheeled robots, unmanned aerial vehicles (UAVs), underwater robots) the dynamics of their actuators play important role. The dynamics of these actuators affects significantly to the accuracy of the control system. The paper proposes an approach to the identification of the dynamic model of actuators of mobile robots illustrated by the UAV propeller as example. The feature of the proposed method is to use the method of least mean squares (LMS) to identify the parameters of nonlinear dynamic objects. The results of experimental research for the actuator of the UAV are presented in paper.
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