Search

The effects of Si addition to Fe on the formation and growth of intermetallic compounds (IMC) in Fe/Al composites were studied by Scanning electron microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and electron backscatter diffraction (EBSD) techniques. The results showed that: when annealing time was 1 h, the critical IMC formation temperature of Pure Al/Pure Fe, Pure Al/Fe+0.82Si, Al+0.88Si/Pure Fe and Al+0.88Si/Fe+0.82Si were 440 °C, 480 °C, 520 °C and 620 °C, respectively. The major IMC phase formed in the four composites after heat treatments at 640 °C/1h and 640 °C/24h was the η phase (Fe2Al5), and a large number of θ phase (Fe4Al13) particles were present in the η phase for the Pure Al/Pure Fe sample. When Si element was added to Fe and Al, Fe3Al2Si3phase and FeAl2Si phase were observed in the η phase. The thickness of the formed IMC layer in the four composites after heat treatment at 640 °C/1h was in the order: Pure Al/Pure Fe ≈ Pure Al/Fe+0.88Si > Al+0.888Si/Pure Fe ≈ Al+0.888Si/Fe+0.88Si. The growth activation energies of the IMC layer in the Pure Al/Pure Fe, Pure Al/Fe+0.82Si, Al+0.88Si/Pure Fe, Al+0.88Si/Fe+0.82Si samples were 76.1 kJ/mol, 276 kJ/mol, 349 kJ/mol and 519.6 kJ/mol, respectively. The effect of Si atoms on the formation of IMC was mainly by the interfacial enrichment mechanism and the new phase inhibition mechanism of FexAlySiz. The enrichment of Si at the interface of Al and Fe increased the growth activation energy and reduce the growth rate of IMC layer thickness. The formation of new FexAlySiz phase can inhibit the rapid growth of IMC phase along the C axis.

Due to the ignoring of rich spatio-temporal and global contextual information with convolutional neural networks in features extraction, the traditional method is prone to tracking drift or even failure in complex scenario, especially for the tiny targets in aerial photography scenario. In this work, it proposes a transformer feature integration network (TFITrack) to obtain diverse and comprehensive target feature for the robust object tracking. Based on the typical transformer architecture, it optimizes encoder and decoder structure for aggregating discriminative spatio-temporal information and global context-awareness feature. Furthermore, the encoder introduces the similarity calculation layer and dual-attention module; the aim is to deepen the similarity between features and make corrections for channel and spatial dimensions, and feature representation is improved. Finally, with the introduction of the temporal context filtering layer, unimportant feature information is ignored adaptively, obtaining a balance between the parameters number reduction and stable performance. Experimental results show that the proposed tracking algorithm exhibits excellent tracking performance on seven benchmark datasets, especially on the aerial dataset UAV123, UAV20L, and UAV123@10fps, which presents the advantages of the novel method in dealing with fast motion and external interference.

This study aimed to investigate the different impacts of sensorial and mobility frailty on overall and domain-specific cognitive function. Further, the independent associations between other intricate capacity (IC) dimensions, including vitality and psychological dimensions, and overall and domain-specific cognitive function were investigated. A total of 429 participants (mean age, 72.91 ± 7.014 years; 57.30% female) underwent IC capacity assessment. Other covariates, such as demographics, health-related variables were also assessed. Overall or domain-specific cognitive impairment was used as a dependent variable in logistic regression analyses adjusted for demographic, health-related, and psychosocial confounders. After adjustment for demographic, health-related, and psychosocial confounders, individuals with sensorial frailty (odds ratio [OR] = 0.435; 95% confidence interval [CI] = 0.236–0.801; P = .008) had a significantly lower risk of mild cognitive impairment (MCI), marginally low delayed memory impairment (OR = 0.601, 95% CI = 0.347–1.040; P = .069), and language impairment (OR = 0.534, 95% CI = 0.305–0.936; OR = 0.318, P = .029; OR = 0.318,95% CI = 0.173–0.586; P < .001) by Boston naming and animal fluency tests than did those with both sensorial and mobility frailty or mobility frailty only. Depressive symptoms had a significant negative influence on executive function. Cardiovascular disease and non-skin malignancy were independent determinants of MCI, and diabetes mellitus was independently associated with processing speed, attention, and executive function. Sensorial and mobility frailty were independent risk factors for cognitive impairment. Mobility frailty had a greater negative influence on the overall cognitive function and memory and language function than did sensorial frailty. The reserve decline in the psychological dimension of IC and chronic diseases also had a significant adverse influence on overall and domain-specific cognition function.

COVID-19 has become a public health emergency due to its rapid transmission. The appearance of pneumonia is one of the major clues for the diagnosis, progress and therapeutic evaluation. More and more literatures about imaging manifestations and related research have been reported. In order to know about the progress and prospective on imaging of COVID-19, this review focus on interpreting the CT findings, stating the potential pathological basis, proposing the challenge of patients with underlying diseases, differentiating with other diseases and suggesting the future research and clinical directions, which would be helpful for the radiologists in the clinical practice and research.

Objective: To explore a method for estimating the amount of myocardium in jeopardy based on CCTA and derive a comprehensive prediction model for coronary lesions with fractional flow reserve (FFR) value of 0.8 or less. Materials and methods: Quantitative features and Myocardial Jeopardy Index (MJI) were measured in 104 coronary arteries of 91 CCTA exams, retrospectively. For 80 left anterior descending (LAD) arteries, the sum of vessel score, diameter stenosis, proximal lesions, apical wrap, long disease, and bifurcation disease were evaluated. The multivariate logistic regression analysis was applied to identify independent predictors for FFR?=?0.8. A LAD-Score was then derived to predict the hemodynamic significance of LAD lesions. Results: MJI, diameter stenosis and minimum lesion diameter were significant independent predictors for FFR?=?0.8 in all 104 vessels at multivariate analysis. The integrated diagnostic accuracy of multi-predictor was increased to 83% from 72% when using stenosis of 70% alone. The area under the receiver operating characteristic curve (AUC) was increased from 0.738 to 0.839 correspondingly. For LAD lesions, the optional cutoff value of stenosis was 62.5%, with a diagnostic accuracy of 71% and AUC of 0.746. Using LAD-Score, the diagnosis accuracy was improved to 84% with AUC of 0.874. Conclusion: The MJI, estimated in CCTA, can help to predict the coronary lesion’s hemodynamic significance more accurately. The LAD-Score, combining LAD lesion features and the amount of myocardium in jeopardy estimated in CCTA, improves the diagnostic performance assessed using invasive FFR.

To investigate whether melatonin (MT) secretion in different parts of the gastrointestinal tract (GIT) exhibits seasonal variations and its correlation with immune regulation.

The depth profiling of the element content and precipitation phase distribution of the AA4045/AA3003mod (Al-1.5Mn-0.35Cu alloy)/AA4045 brazed sheets were investigated by optical microscope observation, electron probe microanalysis (EPMA), focused ion beam-scanning transmission electron microscopy (FIB-STEM). The electrochemical test and sea water acetic acid test (SWAAT) were performed to obtain the evolution of electrochemical responses and corrosion forms of brazed sheet. EPMA results showed that a diffusion layer with the thickness of approximately 50μm existed between the clad layer and core layer, where the Cu diffused from the core layer and Si diffused from the clad layer. It was found that brazing led to a significant low elements solid solution area at the end of the Si diffusion path, where the open circuit potential was lower by 25mV comparing to the unaffected region. Thus the diffusion zone can provide effective cathodic protection to the unaffected region as sacrificial anode by the potential gradient. The SWAAT analysis revealed the corrosion mechanism of the residual cladding was pitting and intergranular corrosion. This area with high density of intermetallic compounds and Si particles increased sensitivity to localized attacks. These results demonstrated the successful application of the FIB-STEM system in illustrating the electrochemical responses and corrosion propagation by an accurate in-depth characterization of intermetallic particles and the matrix solid solution.