187 research outputs found
Piecewise Linear and Nonlinear Window Functions for Modelling of Nanostructured Memristor Device
The present paper reports two new window functions viz. piecewise linear window function and nonlinear window function for modelling of the nanostructured memristor device. The piecewise linear window function can be used for modelling of symmetric pinched hysteresis loop in I-V plane (for digital memory applications) and the nonlinear window function can be used for modelling of nonlinear pinched hysteresis loop in I-V plane (for analog memory applications). Flexibility in the parameter selection is the main attractive feature of these window functions
Piecewise Linear and Nonlinear Window Functions for Modelling of Nanostructured Memristor Device
The present paper reports two new window functions viz. piecewise linear window function and nonlinear window function for modelling of the nanostructured memristor device. The piecewise linear window function can be used for modelling of symmetric pinched hysteresis loop in I-V plane (for digital memory applications) and the nonlinear window function can be used for modelling of nonlinear pinched hysteresis loop in I-V plane (for analog memory applications). Flexibility in the parameter selection is the main attractive feature of these window functions
Characterization of ASR gene and its role in drought tolerance in chickpea (Cicer arietinum L.)
Chickpea has a profound nutritional and economic value in vegetarian society. Continuous
decline in chickpea productivity is attributed to insufficient genetic variability and different
environmental stresses. Chickpea like several other legumes is highly susceptible to terminal
drought stress. Multiple genes control drought tolerance and ASR gene plays a key role
in regulating different plant stresses. The present study describes the molecular characterization
and functional role of Abscissic acid and stress ripening (ASR) gene from chickpea
(Cicer arietinum) and the gene sequence identified was submitted to NCBI Genbank
(MK937569). Molecular analysis using MUSCLE software proved that the ASR nucleotide
sequences in different legumes show variations at various positions though ASR genes are
conserved in chickpea with only few variations. Sequence similarity of ASR gene to chickpea
putative ABA/WDS induced protein mRNA clearly indicated its potential involvement in
drought tolerance. Physiological screening and qRT-PCR results demonstrated increased
ASR gene expression under drought stress possibly enabled genotypes to perform better
under stress. Conserved domain search, protein structure analysis, prediction and validation,
network analysis using Phyre2, Swiss-PDB viewer, ProSA and STRING analysis
established the role of hypothetical ASR protein NP_001351739.1 in mediating drought
responses. NP_001351739.1 might have enhanced the ASR gene activity as a transcription
factor regulating drought stress tolerance in chickpea. This study could be useful in identification
of new ASR genes that play a major role in drought tolerance and also develop functional
markers for chickpea improvement
Investigating the Temperature Effects on ZnO, TiO2, WO3 and HfO2 Based Resistive Random Access Memory (RRAM) Devices
In this paper, we report the effect of filament radius and filament resistivity on the ZnO, TiO2, WO3 and HfO2 based Resistive Random Access Memory (RRAM) devices. We resort to the thermal reaction model of RRAM for the present analysis. The results substantiate decrease in saturated temperature with increase in the radius and resistivity of filament for the investigated RRAM devices. Moreover, a sudden change in the saturated temperature at a lower value of filament radius and resistivity is observed as against the steady change at the medium and higher value of the filament radius and resistivity. Results confirm the dependence of saturated temperature on the filament size and resistivity in RRAM
Investigating the Temperature Effects on ZnO, TiO2, WO3 and HfO2 Based Resistive Random Access Memory (RRAM) Devices
In this paper, we report the effect of filament radius and filament resistivity on the ZnO, TiO2, WO3 and HfO2 based Resistive Random Access Memory (RRAM) devices. We resort to the thermal reaction model of RRAM for the present analysis. The results substantiate decrease in saturated temperature with increase in the radius and resistivity of filament for the investigated RRAM devices. Moreover, a sudden change in the saturated temperature at a lower value of filament radius and resistivity is observed as against the steady change at the medium and higher value of the filament radius and resistivity. Results confirm the dependence of saturated temperature on the filament size and resistivity in RRAM
Chiral topological add–drop filter for integrated quantum photonic circuits
The integration of quantum emitters within topological nanophotonic devices enables the control of light–matter interactions at the single photon level. Here, we experimentally realize an integrated topological add–drop filter and observe multiport chiral emission from single photon emitters (quantum dots) embedded within the device. The filter is imprinted within a valley-Hall photonic crystal membrane and comprises a resonator evanescently coupled to a pair of access waveguides. We show that the longitudinal modes of the resonator enable the filter to perform wavelength-selective routing of light, protected by the underlying topology. Furthermore, we demonstrate that for a quantum dot located at a chiral point in the resonator, selective coupling occurs between well-defined spin states and specific pairs of the filter output ports. The combination of multiport routing, allied with the inherent nonreciprocity of the device at the single photon level, presents opportunities for the formation of complex quantum optical devices, such as an on-chip quantum optical circulator
A semiconductor topological photonic ring resonator
Unidirectional photonic edge states arise at the interface between two topologically distinct photonic crystals. Here, we demonstrate a micrometer-scale GaAs photonic ring resonator, created using a spin Hall-type topological photonic crystal waveguide. Embedded InGaAs quantum dots are used to probe the mode structure of the device. We map the spatial profile of the resonator modes and demonstrate the control of the mode confinement through tuning of the photonic crystal lattice parameters. The intrinsic chirality of the edge states makes them of interest for applications in integrated quantum photonics, and the resonator represents an important building block toward the development of such devices with embedded quantum emitters
A chiral topological add-drop filter for integrated quantum photonic circuits
The integration of quantum emitters within topological nano-photonic devices opens up new avenues for the control of light-matter interactions at the single photon level. Here, we realise a spin-dependent, chiral light-matter interface using individual semiconductor quantum dots embedded in a topological add-drop filter. The filter is imprinted within a valley-Hall photonic crystal (PhC) membrane and comprises a resonator evanescently coupled to a pair of access waveguides. We show that the longitudinal modes of the resonator enable the filter to perform wavelength-selective routing of light, protected by the underlying topology. Furthermore, we demonstrate that for a quantum dot located at a chiral point in the resonator, selective coupling occurs between well-defined spin states and specific output ports of the topological device. This behaviour is fundamental to the operation of chiral devices such as a quantum optical circulator. Our device therefore represents a topologically-protected building block with potential to play an enabling role in the development of chiral integrated quantum photonic circuits
CMB Imprints of a Pre-Inflationary Climbing Phase
We discuss the implications for cosmic microwave background (CMB)
observables, of a class of pre-inflationary dynamics suggested by string models
where SUSY is broken due to the presence of D-branes and orientifolds
preserving incompatible portions of it. In these models the would-be inflaton
is forced to emerge from the initial singularity climbing up a mild exponential
potential, until it bounces against a steep exponential potential of "brane
SUSY breaking" scenarios, and as a result the ensuing descent gives rise to an
inflationary epoch that begins when the system is still well off its eventual
attractor. If a pre-inflationary climbing phase of this type had occurred
within 6-7 e-folds of the horizon exit for the largest observable wavelengths,
displacement off the attractor and initial-state effects would conspire to
suppress power in the primordial scalar spectrum, enhancing it in the tensor
spectrum and typically superposing oscillations on both. We investigate these
imprints on CMB observables over a range of parameters, examine their
statistical significance, and provide a semi-analytic rationale for our
results. It is tempting to ascribe at least part of the large-angle anomalies
in the CMB to pre-inflationary dynamics of this type.Comment: 38 pages, LaTeX, 11 eps figures, references added, matches version to
appear in JCA
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