Super-Tonks-Girardeau Quench in the Extended Bose-Hubbard Model

We investigate the effect of a quench from a one-dimensional gas with strong and repulsive local interactions to a strongly attractive one, known as the super-Tonks-Girardeau effect. By incorporating both an optical lattice and non-local interactions, we discover a previously unexplored phenomenon: the disruption of the state during the quench, but within a specific range of interactions. Our study employs the extended Bose-Hubbard model across various system sizes, starting with analytical results for two atoms and progressing to few-body systems using exact diagonalization, DMRG and TDVP methods. Finally, we use a numerical implementation of the local density approximation for a macroscopic number of atoms. Consistently, our findings unveil a region where the initially self-bound structure expands due to the super-Tonks-Girardeau quench. The fast evaporation provides a tool to characterize the phase diagram in state-of-art experiments exploring the physics of the extended Bose-Hubbard model.Comment: Comments welcome

Resting heart rate and its change induced by physical training in patients with ischemic heart disease at various ages treated with beta-blockers

Background: The present study was aimed at possible modifications of resting HR induced by systematic physical training in patients of different age populations with ischemic heart disease (IHD) subjected to chronic therapeutic beta-blockade. Methods: The goal was the assessment of initial resting heart rate (HR) and its change after 6 months of physical training in two groups of patients with IHD at various ages (A: 55.5 &plusmn; &plusmn; 4.6 years; B: 72.5 &plusmn; 4.37 years) treated with beta-blockers, the dosage of which was not modified during the observation. Results: Comparison between the groups A and B concerned the initial rHR (min-1): 79.3 &plusmn; &plusmn; 8.3 vs. 73.6 &plusmn; 8.3 (p < 0.01), the after-training rHR: 70.9 &plusmn; 7.9 vs. 67.7 &plusmn; 8.4 (NS), and the delta of rHR: -8.4 &plusmn; 4.8 vs. -5.9 &plusmn; 2.8 (p < 0.01). Statistically significant correlation coefficients both between the patients&#8217; ages and the initial rHR (r = -0.377) and the delta of rHR (r = 0.347) were noted. Conclusions: The reduction of rHR after 6-months of training was less in the older IHD patients because of their lower initial rHR compared with the younger patients, which was probably determined more by physiological vagotonia than therapeutic beta-blockade. (Cardiol J 2007; 14: 493-496

Fatigue fracture morphology of AISI H13 steel obtained by additive manufacturing

DEC-10/2021/IDUB/IV.2/EUROPIUM 030/RID/2018/19The paper focuses on researching the effect of fatigue loading on metallic structure, lifetime, and fracture surface topographies in AISI H13 steel specimens obtained by selective laser melting (SLM). The topography of the fracture surfaces was measured over their entire area, according to the entire total area method, with an optical three-dimensional surface measurement system. The fatigue results of the SLM 3D printed steel specimens were compared with those reported for conventionally manufactured 13H steel. The investigation also considers the roughness of the specimens’ side surface. Moreover, the fractographic evaluation conducted using scanning electron microscopy confirms that the predominant fracture mechanism is transgranular fracture. Microtomography done after mechanical loading also showed the influence of the stress level on the porosity distribution. Both fractographic and Micro-CT investigations confirm that higher stresses result in coarser and much more uniform porosity observed in fractured samples. These comprehensive quantitative and qualitative fracture analyses are beneficial to predict the failure conditions of SLM steel parts, especially in the case of fatigue damage. From the quantitative analysis of the H13 SLM-manufactured fracture surface topography, it was possible to conclude that the larger the loadings acting on the specimen, the rougher the fracture surface because the ductile fracture mode dominates. It has also been proven that the porosity degree changes along the length of the sample for the most stressed specimens.publishersversionepub_ahead_of_prin

Lanthanide dopant stabilized Ti3+ state and supersensitive Ti3+ -based multiparametric luminescent thermometer in SrTiO3:Ln3+ (Ln3+ = Lu3+, La3+, Tb3+) nanocrystals

Herein, we show that the substitution of Sr2+ by trivalent lanthanide ions (Lu3+, La3+, Tb3+) in SrTiO3 nanocrystals stabilizes and enhances Ti3+ near-infrared emission (around 800 nm). This emission occurs from the 6-fold coordinated Ti3+ luminescent centers that appear in the vacancy–Ti3+–O form after lanthanide doping into the Sr2+ site. The strong dependence of the Ti3+ emission on temperature provided means for the tailored chemical engineering of luminescent nanonthermometers able to read the temperature in three ways: from the changes in Ti3+ emission intensity, excited-state lifetime, and from the ratio of Tb3+ and Ti3+ emission intensities. We demonstrated the unprecedented temperature sensitivity of the lifetime-based luminescent thermometer (8.83% K−1) with SrTiO3:Tb3+, along with exceptional repeatability in measurements

Strong sensitivity enhancement in lifetime-based luminescence thermometry by co-doping of SrTiO3:Mn4+ nanocrystals with trivalent lanthanide ions

The co-doping of SrTiO3:Mn4+ luminescent nanocrystals with trivalent lanthanide ions (Ln3+ = Lu3+, Tm3+, Er3+, Ho3+, Dy3+, Eu3+, and La3+) is demonstrated as a new strategy for significant sensitivity improvement of lifetime-based luminescent thermometers. SrTiO3:Mn4+:Ln3+ nanocrystals of about 25 nm diameter were prepared by the modified Pechini method and characterized using X-ray powder diffraction and electron microscopy techniques. The temperature dependence of Mn4+ emission in SrTiO3 was considerably altered by the co-doping of Ln3+ due to the cooperating effects of Mn4+ → Ti3+ and Mn4+ → Ln3+ energy transfers. A substantial enhancement of the relative sensitivity of lifetime-based thermometry as high as 145% with respect to the unco-doped nanocrystals reveals the success of the approach. The obtained values of maximal relative sensitivity for different Ln3+ co-dopants are 5.10% K−1 at 290 K for Er3+, 5.00% K−1 at 301 K for Eu3+, 4.84% K−1 at 303 K for Dy3+, 4.71% K−1 at 289 K for Ho3+, and 3.87% K−1 at 290.7 K for Lu3+

Modification of the thermometric performance of the lifetime-based luminescent thermometer exploiting Ti3+ emission in SrTiO3 and CaTiO3 by doping with lanthanide ions

Luminescence thermometry exploiting luminescence kinetics as a thermometric parameter is regarded as one of the most reliable temperature readout techniques. Transition metal ions are of particular interest in this application which is due to the possibility of modulating their spectroscopic properties by changing the strength of the crystal field of the matrix. In this work, we present a strategy to modulate the thermometric parameters including the relative sensitivity and useful temperature range of luminescent thermometers based on the lifetime of Ti3+ ions by introducing lanthanide (Ln3+) doping in SrTiO3 and CaTiO3. The mutual effect of the distortion of the local symmetry of the Ti3+ ions associated with the introduction of Ln3+ ions and/or the Ti3+ → Ln3+ energy transfer enabled relative sensitivities of SR = 5.87% K−1 at 140 K for SrTiO3:Dy3+ and SR = 4.51% K−1 at 251 K for CaTiO3:Gd3+. © 2022 The Author(s