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Fabrication of smooth thin film of vanadium oxides (VO x) using pulsed laser deposition
No full textWe report the synthesis of vanadium oxide thin films by the pulsed laser deposition under different parameter conditions on Si/SiO 2 substrates using V 2O 5 target. The objective of the present work was to achieve smooth VO 2 thin film in a single step. Synergistic effect of the deposition parameters on the phase of vanadium oxides is studied by a series of experiments designed using Taguchi analysis. Conditions for depositing different oxides of vanadium like VO 2, V 2O 3, V 3O 5 and a new phase, V 7O 16 was established. The range of parameters varied were: gas pressure: 10 - 3�5 � 10 - 2 mbar; temperature: 500�700 �C; target-substrate distance: 30�40 mm and laser energy: 100�200 mJ. VO 2 film with surface roughness of 3.68 nm having a semiconductor-to-metal transition (SMT) at 72 �C with 2�3 orders of resistance change was achieved. Taguchi model was statistically analyzed to determine the suitable condition as well as effect of deposition parameters to obtain phase pure VO 2 thin film. The optimum condition for deposition was found to be: gas pressure: 5 � 10 - 2 mbar; temperature: 600 �C; distance: 35 mm, and laser energy: 200 mJ after analyzing using Taguchi model. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature
Reply to Friedrich et al.: Both genetic and environmental factors may contribute to laterality in mesencephalic connectivity and bias
No full textA form of Schwarz's lemma and a bound for the Kobayashi metric on convex domains
No full textWe present a form of Schwarz's lemma for holomorphic maps between convex domains D1 and D2. This result provides a lower bound on the distance between the images of relatively compact subsets of D1 and the boundary of D2. This is a natural improvement of an old estimate by Bernal-González that takes into account the geometry of �D1. Using similar techniques, we also provide a new estimate for the Kobayashi metric on bounded convex domains
The impact of speaking rate on acoustic-to-articulatory inversion
No full textAcoustic characteristics and articulatory movements are known to vary with speaking rates. This study investigates the role of speaking rate on acoustic-to-articulatory inversion (AAI) performance using deep neural networks (DNNs). Since fast speaking rate causes fast articulatory motion as well as changes in spectro-temporal characteristics of the speech signal, the articulatory-acoustic map in a fast speaking rate could be different from that in a slow speaking rate. We examine how these differences alter the accuracy with which different articulatory positions could be recovered from the acoustics. AAI experiments are performed in both matched and mismatched train-test conditions using data of five subjects, in three different rates - normal, fast and slow (fast and slow rates are at least 1.3 times faster and slower than the normal rate). Experiments in matched cases reveal that, the errors in estimating vertical motion of sensors on the tongue articulators from acoustics with fast speaking rate, is significantly higher than those with slow speaking rate. Experiments in mis-matched conditions reveal that there is consistent drop in AAI performance compared to the matched condition. Further experiments performed by training AAI with acoustic-articulatory data pooled from different speaking rates reveal that a single DNN based AAI model is capable of learning multiple rate-specific mapping
Efficient oxygen reduction activity on layered palladium phosphosulphide and its application in alkaline fuel cells
No full textMetal chalcogenides-based electrocatalysts have received considerable attention in recent years. Herein, a layer-type ternary chalcogenide compound, PdPS is proposed as an efficient oxygen reduction reaction electrocatalyst in alkaline medium. PdPS is semiconducting that crystallizes in orthorhombic symmetry. Improvement in conductivity of PdPS using reduced graphene oxide results in excellent electrocatalytic activity. The kinetics is followed by rotating (ring) disk electrode measurements and the composite electrocatalyst is found to be stable, efficient and methanol tolerant. The catalyst is further used as cathode in anion exchange membrane fuel cell and is shown to deliver power density comparable to Pt/C catalyst. In addition, this catalyst is also capable of water oxidation from alkaline solution with favorable electrochemical parameters
An ultralow power nanosensor array for selective detection of air pollutants
No full textSemiconducting metal oxide gas sensors typically operate at a high temperature and consume hundreds of milliwatts of power. Therefore there is great demand for the development of a low-power gas-sensing technology that can sensitively and selectively detect the gas analytes present in the atmosphere. We report an ultralow-power nanosensor array platform, integrated with an independently controlled nanoheater of size 4 mu m x 100 nm, which consumes similar to 1.8 mW power when operated continuously at 300 degrees C. The heaters exhibit a fast thermal response time of less than 1 mu s, and can be utilized to operate in duty cycle mode, leading to power saving. The active area of the nanosensor is 1 mu m x 200 nm, defined by sensing electrodes with a nanogap of similar to 200nm, leading to small form factor. As a proof of concept, each of the sensing elements in the array is functionalized with different sensing materials to demonstrate a low-power, sensitive and selective multiplexed gas-sensing technology for the simultaneous detection of CO (similar to 93.2% for 3 ppm at 300 degrees C), CO2 (similar to 76.3% for 1000 ppm at 265 degrees C), NO2 (similar to 2301% for 3 ppm at 150 degrees C) and SO2 (similar to 94% for 3 ppm at 265 degrees C). The technology described here uses scalable crossbar architecture for sensor elements, thus enabling the integration of additional sensing materials and making it customizable for specific applications
Quantitative earthquake-like statistical properties of the flow of soft materials below yield stress
No full textThe flow behavior of soft materials below the yield stress can be rich and is not fully understood. Here, we report shear-stress-induced reorganization of three-dimensional solid-like soft materials formed by closely packed nematic domains of surfactant micelles and a repulsive Wigner glass formed by anisotropic clay nano-discs having ionic interactions. The creep response of both the systems below the yield stress results in angular velocity fluctuations of the shearing plate showing large temporal burst-like events that resemble seismic foreshocks-aftershocks data measuring the ground motion during earthquake avalanches. We find that the statistical properties of the quake events inside such a burst map on to the scaling relations for magnitude and frequency distribution of earthquakes, given by Gutenberg-Richter and Omori laws, and follow a power-law distribution of the inter-occurrence waiting time. In situ polarized optical microscopy reveals that during these events the system self-organizes to a much stronger solid-like state
Joint channel and Doppler estimation for OSDM underwater acoustic communications
No full textOrthogonal signal-division multiplexing (OSDM) has recently emerged as a promising modulation scheme for underwater acoustic communications. Although providing more flexibility in system design, it suffers from a special interference structure over time-varying channels. To enable reliable OSDM equalization, we propose a joint channel impulse response and Doppler estimation algorithm in this paper. Compared to the existing method, which solves a nonconvex bilinear optimization problem iteratively in the frequency domain without a guarantee of global optimality, the proposed algorithm transforms the problem into a convex quadratic minimization in the time domain and can achieve a closed-form solution
A simple method to extract zeros of certain Eisenstein series of small level
No full textThis paper provides a simple method to extract the zeros of some weight two Eisenstein series of level N where N= 2 , 3 , 5 and 7. The method is based on the observation that these Eisenstein series are integral over the graded algebra of modular forms on SL(2, Z) and their zeros are �controlled� by those of E4 and E6 in the fundamental domain of � (N).
Control of locomotory behavior of caenorhabditis elegans by the immunoglobulin superfamily protein RIG-3
No full textCell surface immunoglobulin superfamily (IgSF) proteins play important roles in the development and function of the nervous system . Here we define the role of a Caenorhabditis elegans IgSF protein, RIG-3, in the function of the AVA command interneuron. This study reveals that RIG-3 regulates the abundance of the glutamate receptor subunit, GLR-1, in the AVA command interneuron and also regulates reversal behavior in C. elegans. The mutant strain lacking rig-3 (rig-3 (ok2156)) shows increased reversal frequency during local search behaviors. Genetic and behavioral experiments suggest that RIG-3 functions through GLR-1 to regulate reversal behavior. We also show that the increased reversal frequency seen in rig-3 mutants is dependent on the increase in GLR-1 abundance at synaptic inputs to AVA, suggesting that RIG-3 alters the synaptic strength of incoming synapses through GLR-1. Consistent with the imaging experiments, altered synaptic strength was also reflected in increased calcium transients in rig-3 mutants when compared to wild-type control animals. Our results further suggest that animals lacking rig-3 show increased AVA activity, allowing the release of FLP-18 neuropeptide from AVA, which is an activity-dependent signaling molecule. Finally, we show that FLP-18 functions through the neuropeptide receptor, NPR-5, to modulate reversal behavior in C. elegans