物理最新文献

The increasing use of CMOS technology has made it essential to improve its resistance to laser damage in the field of optoelectronic countermeasures. This research examines the characteristics and mechanisms of damage to CMOS caused by 1064 nm continuous lasers and 532 nm pulsed lasers. The damage progresses through four stages: lens damage, point damage, line damage, and stress damage. Results show that continuous laser exposure leads to gradual expansion of the damaged area over time, while narrow-pulse multi-pulse lasers cause more severe damage to CMOS. Lens and point damage are mainly caused by thermal ablation, which reduces the CMOS light source’s focusing efficiency and damages the MOS structure. Line and stress damage result from a combination of thermal ablation and thermal stress. Damage to the metal wiring layer can cause entire rows or columns of pixels to fail, while the insulation layer may rupture due to thermal stress expansion, ultimately leading to CMOS function failure during imaging.

This paper investigates the massive gauge field within spacetime context from a (mathbb {Z}_2) quotient of the constant curvature black hole. We investigate how the matter field’s back reaction affects the spacetime geometry, considering perturbations in the metric up to the first order. The stress-energy tensor’s expectation value can be precisely calculated by evaluating its pull-back onto the covering space. By appropriately selecting boundary conditions for the massive vector field along a non-contractible cycle of the quotient manifold, achieving a negative average energy along a null geodesic becomes feasible, enabling a traversable wormhole.

This work thoroughly investigated the adaptability of Gd-incorporated spinel Ni–Zn ferrite nanoparticles in hyperthermia and photocatalytic applications. The chemical co-precipitation method was utilized to fabricate these ferrite nanoparticles containing different weight percentages of Gd dopants, and tuned physical properties, including microstructural, optical, and magnetic were examined. The formation of spinel cubic crystal structure and phase-purity of prepared samples was confirmed by analyzing the x-ray diffractograms. Both the developed microstrain due to doping and mean crystallite sizes were estimated using the Williamson-Hall (W–H) graph. With the aid of HRTEM images, the morphology, average size of nanoparticles and regularity in shape were studied carefully. Mean particle diameters of entire ferrite samples were observed to reduce with the increase of Gd ions in the host structure. A blue shift in the optical indirect band gaps with the increase of Gd content was noticed for synthesized ferrite samples. All the Raman active modes of spinel structure were found in deconvoluted Raman spectra. Because of the paramagnetic behavior of Gd ions, there was a dilution of magnetic properties observed at room temperature. A careful investigation revealed that the doped ferrite samples were suitable for hyperthermia application as the generated heat was suitable to burst cancer cells in a biological medium. Because of the increase in specific surface area and magnitude of negative zeta potential for doped ferrite nanoparticles, these samples showed excellent efficiency in degrading toxic cationic rhodamine B (RhB) dye. The highest Gd-doped ferrite containing the smallest nanoparticles was capable enough to degrade 94.6% RhB dye in 2.5 h. With increasing Gd content in nanosized spinel Ni–Zn ferrites, the efficiency of dye degradation was found to increase significantly. Therefore, Gd-substituted Ni–Zn ferrite nanoparticles are efficient nanomaterials to be utilized in both photocatalytic and hyperthermia applications.

Graphical abstract

Gradient nano-grained (GNG) metals usually exhibit a strength–ductility trade-off compared with their homogeneous counterparts, but the understanding on the gradient distribution in grain size corresponding to the optimal strength–ductility trade-off is still limited. Here, the tensile processes of GNG Cu with different grain-size gradient distributions are simulated by the crystal plasticity finite element method (CPFEM). The influence of grain-size gradient rate on the mechanical behaviors of strength and plasticity, and the distribution of strain and stress are analytical analyzed, and the relations between the structural gradient and the deformation gradient are investigated. It is found that the GNG Cu has optimal strength-ductility trade-off and the largest extra strengthening effect, when the gradient distribution in grain size meets a linear relationship. It is also found that the optimal strength-ductility trade-off comes from the largest deformation gradient and favorite multiaxial stress. These simulation results obtained by CPFEM are in accordance with the experiment observations and that obtained by MD simulations on atomic scales.

In the (U(3) times U(3)) quark NJL model, (tau ) lepton decays with the production of scalar mesons (f_0(pi ,K)) and neutrinos are studied, where (f_0=f_0(500), f_0(980)). It is shown that these decays mainly occur via contact channels and channels with axial-vector mesons (a_1(1260)), (K_1(1270)) and (K_1(1400)). All mesons are considered as quark-antiquark states in this case. The obtained results can be considered as predictions for future experiments. The obtained estimates for the branching fractions of the (tau rightarrow pi ^-2pi ^0 nu _tau ) decay taking into account the contributions of the (rho pi ) and (f_0(500)pi ) states are in satisfactory agreement with experimental data.

Laser-induced forward transfer (LIFT) is gaining significant attention as a non-contact printing technique for high-viscosity conductive inks in printed electronics. However, the high wet thickness of printed tracks is essential for achieving effective electrical pathways, a requirement that has not been thoroughly considered so far. The wet thickness is a function of ink viscosity, substrate wettability, and the laser processing parameters. In this study, the printing mechanism of conductive graphene inks with viscosities ranging from 1 to 15 Pa.s using LIFT was investigated. The effects of pulse energy (30 to 120 µJ) and gap distance (50 to 300 μm) in printing voxels with a green nanosecond laser were systematically examined, providing a phenomenological understanding of the material transfer mechanism. The findings highlight the significant role of the temporal pulse distance in enhancing the wet thickness achievable during LIFT of high-viscosity inks, attributed to capillary healing phenomena. Additionally, the acceptor substrates’ hydrophobicity was found to increase the wet thickness and improve the resolution of the printed voxels/tracks. Especially, the aspect ratio of LIFT-printed tracks was increased by more than 175% with 10 printing passes when a hydrophobic accepter was used. So, the optimal LIFT processing conditions were identified to achieve high-quality, high-aspect-ratio tracks, by considering synergistically the effects of the temporal pulse distance and the substrate wettability. Moreover, the resistivity of the LIFT-printed graphene tracks decreased by more than 84% after a 100-minute sintering step at 120 °C. This research advances understanding of LIFT printing high-viscosity conductive inks, particularly underpinning the development of high-resolution and high-aspect-ratio electrical circuits for printed electronics.

In this paper, the accelerating expansion of the universe has been investigated in the multi-components fluid in the coupling of geometry with matter alternative theory f(R, T) gravity, where the gravitational Lagrangian is given by an arbitrary function of the Ricci scalar R and of the trace of the stress-energy tensor T. To address the late-time accelerating universe, we solve the Friedmann equations via the nonzero divergence of the energy-momentum tensor considered in the presence of a multi-component fluid. The best-fit values of the model parameters are determined using the Markov Chain Monte Carlo (MCMC) simulation using the cosmic chronometers (CC) dataset, which consists of 31 points and the recent Pantheon+ analysis of 1701 light curves of 1550 distinct Type Ia supernovae (SNIa) ranging in redshift from (z = 0.001) to 2.26. The trajectory of the deceleration parameter indicates that the universe has transitioned from a deceleration phase to an acceleration phase. We also look into the behavior of the jerk and snap parameters, the statefinder analysis, the om diagnostic, and the effective EoS parameter. It is shown that the model considered is consistent with the accelerating universe and the predictions of the quintessence model at present.