All-optical switching in plant blue light photoreceptor phototropin

We theoretically analyze all-optical switching in the recently characterized LOV2 domain from Avena sativa (oat) phot1 phototropin, a blue-light plant photoreceptor, based on nonlinear intensity-induced excited-state absorption. The transmission of a cw probe laser beam at 660 nm corresponding to the peak absorption of the first excited L-state, through the LOV2 sample, is switched by a pulsed pump laser beam at 442 nm that corresponds to the maximum initial D state absorption. The switching characteristics have been analyzed using the rate equation approach, considering all the three intermediate states and transitions in the LOV2 photocycle. It is shown that for a given pump pulse intensity, there is an optimum pump pulsewidth for which the switching contrast is maximum. It is shown that the probe laser beam can be completely switched off (100% modulation) by the pump laser beam at 50 kW/cm² for a concentration of 1 mM with sample thickness of 5.5 mm. The switching characteristics are sensitive to various parameters such as concentration, rate constant of L-state, peak pump intensity and pump pulse width. At typical values, the switch-off and switch-on time is 1.6 and 22.3 mus, respectively. The switching characteristics have also been used to design all-optical not and the universal nor and nand logic gates     

Effect of Magnetic (Nd) Doping on Electrical and Magnetic Properties of Topological Sb2Te3 Single Crystal

Journal of Superconductivity and Novel Magnetism - Here, we report the growth and characterization of single crystals of NdxSb2-xTe3 (x?=?0 and 0.1), by solid-state reaction route via...     

3D Path Optimisation of Unmanned Aerial Vehicles Using Q Learning-Controlled GWO-AOA

Unmanned Aerial Vehicles (UAVs) or drones introduced for military applications are gaining popularity in several other fields as well such as security and surveillance, due to their ability to perform repetitive and tedious tasks in hazardous environments. Their increased demand created the requirement for enabling the UAVs to traverse independently through the Three Dimensional (3D) flight environment consisting of various obstacles which have been efficiently addressed by metaheuristics in past literature. However, not a single optimization algorithms can solve all kind of optimization problem effectively. Therefore, there is dire need to integrate metaheuristic for general acceptability. To address this issue, in this paper, a novel reinforcement learning controlled Grey Wolf Optimisation-Archimedes Optimisation Algorithm (QGA) has been exhaustively introduced and exhaustively validated firstly on 22 benchmark functions and then, utilized to obtain the optimum flyable path without collision for UAVs in three dimensional environment. The performance of the developed QGA has been compared against the various metaheuristics. The simulation experimental results reveal that the QGA algorithm acquire a feasible and effective flyable path more efficiently in complicated environment.     

Erosive wear behavior of spark plasma-sintered SiC–TaC composites

Spark plasma sintering of SiC-10, 20, or 30 wt% TaC composites was performed at 1800°C. Microstructures of sintered composites revealed uniform dispersion of TaC particles in SiC matrix. With the increase in TaC content, hardness decreased from 25.75 to 23.30 GPa and fracture toughness increased from 3.48 to 3.85 MPa m^1/2. Erosion testing was performed to evaluate the potential of sintered composites at room temperature and 400°C by a stream of SiC particles impinging at different angles (30°, 60°, or 90°). The erosion rate varied from 25 to 166 mm³/kg, with change in TaC content, impingement angle, or temperature. The erosion rate increased as the angle of impingement and temperature increased, but reduced when the TaC concentration increased. Worn surfaces revealed that the material was dominantly removed via fracture of SiC grains and TaC particles pull-out. SiC-30 wt% TaC composites exhibited superior erosive wear resistance at low impingement angle and room temperature.     

Quantification of Deviation of Size Dependent Field Enhancement Factor of Silicon Nanowires Array through Theoretical Modeling

Silicon - In the present paper, we report the observations of field emission (FE) from silicon nanowires array (Si-NWsA) synthesized on p-type Si (100) using wet chemical etching (WCE) approach,...