A magnetically, electrically or mechanically responsive material can undergo significant thermal changes near a ferroic phase transition when its order parameter is modified by the conjugate applied ...field. The resulting magnetocaloric, electrocaloric and mechanocaloric (elastocaloric or barocaloric) effects are compared here in terms of history, experimental method, performance and prospective cooling applications.
•Cobalt ferrite nanoparticles prepared by the auto combustion method.•Dielectric relaxation was explained by impedance spectroscopy.•Interfacial polarization plays important role in cobalt ferrite ...nanoparticles.•Overlap large polaron tunneling conduction is responsible for ac conductivity.•DC conductivity is mainly due to the small polaron conduction.
The electric transport behavior of nano cobalt ferrite was studied in details within frequency window of 100Hz and 1MHz in the range of temperature of 25–200°C. No grain relaxation was observed whereas interfaces (grain boundary and electrode surface contact) became the dominant conduction regions. Both ac and dc conduction mechanism was investigated thoroughly. Overlapping of large polaron tunneling (OLPT) mechanism was found to be responsible for ac conduction process. The value obtained for mobility (10−10cm2/Vs) of charge carriers indicated the possible small polaron hopping for dc conduction process. The dc resistivity data was fitted with Mott and Davis model and the derived parameters confirmed the dc conduction of non-adiabatic nature which was due to small polaron hopping in nano cobalt ferrite.
Among patients with heart failure and secondary mitral regurgitation, transcatheter mitral-valve repair resulted in a lower rate of hospitalization for heart failure and lower mortality than medical ...therapy alone. The goal for freedom from device-related complications was exceeded.
Background: Willingness to quit in a tobacco user forms the basis for future quit attempts and quitting successfully. Objective: To determine the prevalence and correlates of willingness to quit ...among tobacco users in India using the Global Adult Tobacco Survey (GATS), India, 2016-2017. Methods: GATS, 2016-17 was a multistage geographically clustered sample survey done among 74,037 individuals aged 15 years and above across all the states and two of the Union Territories of India. Data of all those reported using any form of tobacco were studied for past attempts to quit tobacco, advised to quit by a health care provider, and exposure to anti-tobacco messages delivered through various media and the correlation of these with the willingness to quit using multivariate analysis. Results: Of the 21,085 current tobacco users in the survey, 11,679 (52.2%), were willing to quit all forms of tobacco. Multivariate analysis showed that those in younger age groups (OR: 1.39 1.23-1.56), higher education levels (OR 1.15 1.05-1.18), time of first tobacco use in the day being more than 60 min after waking up in the morning (OR 1.11 1.03-1.2), history of attempts to quit in the past 12 months (OR 1.78 1.69-1.87), those advised to quit by health care provider in the past 12 months (OR 1.11 1.06-1.17), those using single form of tobacco (OR 1.1 1.05-1.17), those exposed to anti-tobacco messages in newspapers/magazines (OR 1.1 1.05-1.17), and cinemas (1.14 1.08-1.20) were more willing to quit compared to their counterparts. Conclusion: Enhanced publicizing of anti-tobacco messages through the currently employed media, and ensuring that doctors give a brief advice to quit during any contact with a tobacco user could improve the willingness to quit and the consequent quit rate, especially among those tobacco users who are in younger age groups and who have attempted to quit earlier.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In this paper, we extend our investigation about the generalized comaximal graph introduced in Biswas et al. (Discrete Math Algorithms Appl 11(1):1950013, 2019a). The generalized comaximal graph is ...defined as follows: given a finite commutative ring
R
, the generalized comaximal graph
G
(
R
) is an undirected graph with its vertex set comprising elements of
R
and two distinct vertices
u
,
v
are adjacent if and only if there exists a non-zero idempotent
e
∈
R
such that
u
R
+
v
R
=
e
R
. In this study, we focus on identifying the rings
R
for which the graph
G
(
R
) exhibits planarity. Moreover, we provide a characterization of the class of ring for which
G
(
R
) is toroidal, denoted by
γ
(
G
(
R
)
)
=
1
. Furthermore, we also evaluate the energy of the graph
G
(
R
). Finally, we demonstrate that the graph
G
(
R
) is always Hamiltonian for any finite commutative ring
R
.
The paper studies average consensus with random topologies (intermittent links) and noisy channels. Consensus with noise in the network links leads to the bias-variance dilemma-running consensus for ...long reduces the bias of the final average estimate but increases its variance. We present two different compromises to this tradeoff: the A - ND algorithm modifies conventional consensus by forcing the weights to satisfy a persistence condition (slowly decaying to zero;) and the A - NC algorithm where the weights are constant but consensus is run for a fixed number of iterations ^(iota), then it is restarted and rerun for a total of ^( p ) runs, and at the end averages the final states of the ^( p ) runs (Monte Carlo averaging). We use controlled Markov processes and stochastic approximation arguments to prove almost sure convergence of A - ND to a finite consensus limit and compute explicitly the mean square error (mse) (variance) of the consensus limit. We show that A - ND represents the best of both worlds-zero bias and low variance-at the cost of a slow convergence rate; rescaling the weights balances the variance versus the rate of bias reduction (convergence rate). In contrast, A - NC , because of its constant weights, converges fast but presents a different bias-variance tradeoff. For the same number of iterations ^(iota)^( p ) , shorter runs (smaller ^(iota) ) lead to high bias but smaller variance (larger number ^( p ) of runs to average over.) For a static nonrandom network with Gaussian noise, we compute the optimal gain for A - NC to reach in the shortest number of iterations ^(iota)^( p ) , with high probability (1-delta), (epsiv, delta)-consensus (epsiv residual bias). Our results hold under fairly general assumptions on the random link failures and communication noise.
Abstract
Atomically thin two-dimensional (2D) Janus materials and their Van der Waals heterostructures (vdWHs) have emerged as a new class of intriguing semiconductor materials due to their versatile ...application in electronic and optoelectronic devices. Herein, We have invstigated most probable arrangements of different inhomogeneous heterostructures employing one layer of transition metal dichalcogenide, TMD (MoS
2
, WS
2
, MoSe
2
, and WSe
2
) piled on the top of Janus TMD (MoSeTe or WSeTe) and investigated their structural, electronic as well as optical properties through first-principles based calculations. After that, we applied twist engineering between the monolayers from 0
$$^{\circ } \rightarrow$$
∘
→
60
$$^{\circ }$$
∘
twist angle, which delivers lattice reconstruction and improves the performance of the vdWHs due to interlayer coupling. The result reveals that all the proposed vdWHs are dynamically and thermodynamically stable. Some vdWHs such as MoS
2
/MoSeTe, WS
2
/WSeTe, MoS
2
/WSeTe, MoSe
2
/MoSeTe, and WS
2
/MoSeTe exhibit direct bandgap with type-II band alignment at some specific twist angle, which shows potential for future photovoltaic devices. Moreover, the electronic property and carrier mobility can be effectively tuned in the vdWHs compared to the respective monolayers. Furthermore, the visible optical absorption of all the Janus vdWHs at
$$\theta$$
θ
= 0
$$^{\circ }$$
∘
can be significantly enhanced due to the weak inter-layer coupling and redistribution of the charges. Therefore, the interlayer twisting not only provides an opportunity to observe new exciting properties but also gives a novel route to modulate the electronic and optoelectronic properties of the heterostructure for practical applications.
Electron-positron pair plasmas represent a unique state of matter, whereby there exists an intrinsic and complete symmetry between negatively charged (matter) and positively charged (antimatter) ...particles. These plasmas play a fundamental role in the dynamics of ultra-massive astrophysical objects and are believed to be associated with the emission of ultra-bright gamma-ray bursts. Despite extensive theoretical modelling, our knowledge of this state of matter is still speculative, owing to the extreme difficulty in recreating neutral matter-antimatter plasmas in the laboratory. Here we show that, by using a compact laser-driven setup, ion-free electron-positron plasmas with unique characteristics can be produced. Their charge neutrality (same amount of matter and antimatter), high-density and small divergence finally open up the possibility of studying electron-positron plasmas in controlled laboratory experiments.
The acceleration of ions from ultrathin foils has been investigated by using 250 TW, subpicosecond laser pulses, focused to intensities of up to 3 × 10(20) W cm(-2). The ion spectra show the ...appearance of narrow-band features for protons and carbon ions peaked at higher energies (in the 5-10 MeV/nucleon range) and with significantly higher flux than previously reported. The spectral features and their scaling with laser and target parameters provide evidence of a multispecies scenario of radiation pressure acceleration in the light sail mode, as confirmed by analytical estimates and 2D particle-in-cell simulations. The scaling indicates that monoenergetic peaks with more than 100 MeV/nucleon are obtainable with moderate improvements of the target and laser characteristics, which are within reach of ongoing technical developments.
Abstract
Semiconductors with controllable electronic transport coupled with magnetic behaviour, offering programmable spin arrangements present enticing potential for next generation intelligent ...technologies. Integrating and linking these two properties has been a long standing challenge for material researchers. Recent discoveries in two-dimensional (2D) magnet shows an ability to tune and control the electronic and magnetic phases at ambient temperature. Here, we illustrate controlled spin transport within the magnetic phase of the 2D semiconductor CrOBr and reveal a substantial connection between its magnetic order and charge carriers. First, we systematically analyse the strain-induced electronic behaviour of 2D CrOBr using density functional theory calculations. Our study demonstrates the phase transition from a magnetic semiconductor → half metal → magnetic metal in the material under strain application, creating intriguing spin-resolved conductance with 100% spin polarisation and spin-injection efficiency. Additionally, the spin-polarised current–voltage (I–V) trend displayed conductance variations with high strain-assisted tunability and a peak-to-valley ratio as well as switching efficiency. Our study reveals that CrOBr can exhibit highly anisotropic behaviour with perfect spin filtering, offering new implications for strain engineered magneto-electronic devices.
PDF
