BiFeO3-based composite materials are important due to their versatile multiferroic properties which can be further tuned upon doping. 0.5BiNdxFe1-xO3-0.5PbZrO3 (x = 0.05, 0.1, and 0.2) ...polycrystalline ceramic samples were prepared by solid-state reaction technique at high temperature. X-ray diffraction (XRD) and Rietveld refinement process confirm the presence of mainly rhombohedral (R3c) phase. Dielectric studies reveal the presence of Maxwell-Wagner type polarization. Electric impedance and modulus values of the samples were studied over a wide range of temperature and frequency. Complex impedance and modulus studies shows the presence of non-Debye type of relaxation in the materials. ac conductivity results can be fitted with Jonscher's power law and indicates the dominance of correlated barrier hopping mechanism in charge transport. Furthermore, density of states calculated from ac conductivity shows variation as a function of dopant content which is further corroborated from density functional theory-based results.
•Synthesis of Nd-doped BFO-PZO composites.•Rietveld refinement confirming rhombohedral (R3c) phase.•Complex impedance spectroscopy for understanding conduction mechanism.•CBH model for conduction, DOS, and hopping length calculation.•Bader charge calculation with Nd doping using DFT.
Migraine is a complex disorder characterized by debilitating headaches. Despite its prevalence, its pathophysiology remains unknown, with subsequent gaps in diagnosis and treatment. We combined ...machine learning with connectivity analysis and applied a whole-brain network approach to identify potential targets for migraine diagnosis and treatment.
Baseline anatomical T1 magnetic resonance imaging (MRI), resting-state functional MRI(rfMRI), and diffusion weighted scans were obtained from 31 patients with migraine, and 17 controls. A recently developed machine learning technique, Hollow Tree Super (HoTS) was used to classify subjects into diagnostic groups based on functional connectivity (FC) and derive networks and parcels contributing to the model. PageRank centrality analysis was also performed on the structural connectome to identify changes in hubness.
Our model attained an area under the receiver operating characteristic curve (AUC-ROC) of 0.68, which rose to 0.86 following hyperparameter tuning. FC of the language network was most predictive of the model's classification, though patients with migraine also demonstrated differences in the accessory language, visual and medial temporal regions. Several analogous regions in the right hemisphere demonstrated changes in PageRank centrality, suggesting possible compensation.
Although our small sample size demands caution, our preliminary findings demonstrate the utility of our method in providing a network-based perspective to diagnosis and treatment of migraine.
Atomic layer deposited (ALD) samples with layer stacks of HfO
2
(3 nm)/SiO
2
(0.7 nm)/ Si were subjected to 120 MeV Au ion irradiation at different fluences to study intermixing effects across the ...HfO
2
/SiO
2
interface. High-resolution Rutherford backscattering spectrometry (HRBS) and X-ray reflectivity (XRR) measurements confirm an increase in the interlayer thickness as a result of SHI induced intermixing effects. Current–voltage (I–V) measurements reveal an order of magnitude difference in the leakage current density between the pristine and irradiated samples. This can be explained by considering the increased physical thickness of interlayer (HfSiO). Furthermore, the samples were subjected to rapid thermal annealing (RTA) process to analyze annealing kinetics.
The content and neural representation of autobiographical memories change over time; however, these changes are poorly understood. We hypothesize that the content of memories becomes semanticized, ...while the neural representation moves from mesial to cortical structures. We conducted an fMRI (functional magnetic resonance imaging) study on the effects of time on autobiographical memory retrieval. Twenty healthy participants were cued by a selection of photographs that represented distinct episodic memories from 1, 2, 6, and 14 years prior to scanning. Our behavioural data of self‐report measures of memory qualia suggests a loss of episodic content over time. GLM (general linear model) results demonstrate that across all time points, visual association cortices and mesial temporal lobes were activated. However, we did not observe any GLM differences between memory time points. We used SVM (support vector machine) in order to predict memory time point based on neural activation patterns. We were able to accurately predict classification accuracy for the 1‐year (66.7%), 2‐year (66.7%), and 14‐year (33.4%) memory time points, with an overall classification accuracy of 55.6%. We suggest that our findings can be interpreted in light of cortical semantization; as memories age, they become more semanticized and shift in representation towards cortical structures.
We propose to estimate the untightness of the cylinder of an internal combustion engine, which depends on the wear of the sealing ring of a piston, according to the value of its gap, volume and rate ...of gas scavenging to the crankshaft box. It is shown that, in the first approximation, the untightness of the lock of a ring is a linear function of the rate of gas scavenging.
The article presents the possibilities of using artificial intelligence methods to model the injection doses of a modern Common Rail (CR) fuel injector. The presented neural network solution belongs ...to the experimental models known as black boxes in mechatronics. The backpropagation algorithm and its Levenberg-Marquardt expansion were used for the simulation. The analysis showed that there is a good match between the measurements and the computational model. The proposed solution can be used in the processes of diagnosing not only elements of the injection equipment, but also the internal combustion engine. The paper presents the construction and operation of fuel injectors and the important role of precision pairs work.
This article describes evidence for contact and exchange among Mesolithic communities in Poland and Scandinavia, based on the interdisciplinary analysis of an ornamented bâton percé from Gołębiewo ...site 47 (Central Poland). Typological and chronological-cultural analyses show the artefact to be most likely produced in the North European Plain, during the Boreal period. Carbon-14 dating confirms the antiquity of the artefact. Ancient DNA analysis shows the artefact to be of Rangifer tarandus antler. Following this species designation, a dispersion analysis of Early-Holocene reindeer remains in Europe was conducted, showing this species to exist only in northern Scandinavia and north-western Russia in this period. Therefore, the bâton from Gołębiewo constitutes the youngest reindeer remains in the European Plain and south-western Scandinavia known to date. An attempt was made to determine the biogeographic region from which the antler used to produce the artefact originates from. To this end, comprehensive δ18O, δ13C and δ15N isotope analyses were performed. North Karelia and South Lapland were determined as the most probable regions in terms of isotopic data, results which correspond to the known distribution range of Rangifer tarandus at this time. In light of these finds, the likelihood of contact between Scandinavia and Central Europe in Early Holocene is evaluated. The bâton percé from Gołębiewo is likely key evidence for long-distance exchange during the Boreal period.
The radiation response, long-term performance, and reliability of HfO
2
-based gate dielectric materials play a critical role in metal oxide semiconductor (MOS) technology for space device ...applications. Al/HfO
2
/Si atomic layer-deposited devices were irradiated by gamma and swift heavy ions. An increase in the leakage current and charge trapping has been observed as the gamma irradiation dose varied from 25 to 100 krad. The density of oxide traps is found to increase with an increase in the gamma dose while the interface trap density is found to decrease. Another set of samples were irradiated by 120 MeV Au ions to study the SHI-induced defect annealing/creation of defects and intermixing effects in HfO
2
/Si-based devices. The formation of an interfacial layer of HfSiO at a fluence of at 5 × 10
13
cm
−2
is revealed by X-ray reflectivity analysis. The densities of interface- and oxide-trapped charges are found to decrease up to a critical fluence of 1 × 10
12
cm
−2
and then increase with further increase in fluence to 5 × 10
13
cm
−2
. The presence of the interlayer, due to the swift heavy ion-induced intermixing, has been confirmed by X-ray photoelectron spectroscopy measurements. Various current conduction mechanisms in both substrate and gate injection cases were used to understand the basic mechanisms of direct, Fowler–Nordheim, and Poole–Frenkel tunneling, as well as Schottky emission in these devices. These studies elucidated the radiation tolerance and charge-trapping behavior of Al/HfO
2
/Si nMOS capacitors.
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