In recent years, with the development of materials science, the joining technology is also constantly upgraded, ultrasonic testing technology can more accurately detect the defects or failures of new ...materials in the new joining process, which has extensive applications in the field of engineering joining, such as welding, mechanical joining, and adhesive bonding. This paper introduces the common non-destructive testing techniques, including magnetic particle testing, eddy current testing, penetration testing, radiographic testing, and ultrasonic testing. The main principles and devices of ultrasonic testing are introduced, including air-coupled ultrasonic testing, electromagnetic ultrasonic testing, laser ultrasonic testing, and so on. The current status of the application of ultrasonic testing in welded joints, riveted joints, bonded joints, and bolted joints is summarized and reviewed. Finally, the drawbacks of ultrasonic testing in this field are discussed, as well as prospective research directions.
In recent years, with the deepening of research on ultrasonics, it has been discovered that the introduction of ultrasonics can improve the efficiency and performance of joining processes such as ...welding, riveting (clinching) and adhesive bonding, so the application of ultrasound in joining has received extensive attention. This paper introduces the application of ultrasonic vibration in joining from two aspects: ultrasonic systems and principles, and the application of ultrasound in joining processes. The principles, research status, current problems, and future development directions of ultrasonic welding, ultrasonic spot welding, ultrasonic brazing, ultrasonic transient liquid phase diffusion welding, ultrasonic stir friction welding, ultrasonic arc welding, ultrasonic-assisted mechanical joining, and ultrasonic bonding are systematically described. Finally, all of the information is integrated to highlight the existing challenges of ultrasonic vibration in the field of joining and to point out where further research is needed.
It is well established that epilepsy is characterized by the destruction of the information capacity of brain network and the interference with information processing in regions outside the ...epileptogenic focus. However, the potential mechanism remains poorly understood. In the current study, we applied a recently proposed approach on the basis of resting-state fMRI data to measure altered local neural dynamics in mesial temporal lobe epilepsy (mTLE), which represents how long neural information is stored in a local brain area and reflect an ability of information integration. Using resting-state-fMRI data recorded from 36 subjects with mTLE and 36 healthy controls, we calculated the intrinsic neural timescales (INT) of neural signals by summing the positive magnitude of the autocorrelation of the resting-state brain activity. Compared to healthy controls, the INT values were significantly lower in patients in the right orbitofrontal cortices, right insula, and right posterior lobe of cerebellum. Whereas, we observed no statistically significant changes between patients with long- and short-term epilepsy duration or between left-mTLE and right-mTLE. Our study provides distinct insight into the brain abnormalities of mTLE from the perspective of the dynamics of the brain activity, highlighting the significant role of intrinsic timescale in understanding neurophysiological mechanisms. And we postulate that altered intrinsic timescales of neural signals in specific cortical brain areas may be the neurodynamic basis of cognitive impairment and emotional comorbidities in mTLE patients.
The rapid development of computer science over the past few decades has led to unprecedented progress in the field of artificial intelligence (AI). Its wide application in ophthalmology, especially ...image processing and data analysis, is particularly extensive and its performance excellent. In recent years, AI has been increasingly applied in optometry with remarkable results. This review is a summary of the application progress of different AI models and algorithms used in optometry (for problems such as myopia, strabismus, amblyopia, keratoconus, and intraocular lens) and includes a discussion of the limitations and challenges associated with its application in this field.
In response to hyperglycemia in patients with diabetes, many signaling pathways contribute to the pathogenesis of diabetic complications, including diabetic retinopathy (DR). Excessive production of ...inflammatory mediators plays an important role in this process. Amadori-glycated albumin, one of the major forms of advanced glycated end-products, has been implicated in DR by inducing inflammatory responses in microglia/macrophages. Our goal was to delineate the potential cross talk between class A scavenger receptor (SR-A) and the receptor for advanced glycated end-product (RAGE) in the context of DR. We show here that SR-A ablation caused an exacerbated form of DR in streptozotocin-injected C57BL/6J mice as evidenced by fundus imaging and electroretinography. Immunohistochemical staining and RT-PCR assay indicated that there was augmented activation of proinflammatory macrophages with upregulated synthesis of proinflammatory mediators in the retina in Sr-a(-/-) mice. Overexpression of SR-A suppressed RAGE-induced mitogen-activated protein kinase (MAPK) signaling, whereas RAGE activation in macrophages favored a proinflammatory (M1) phenotype in the absence of SR-A. Mechanistic analysis on bone marrow-derived macrophages and HEK293 cell line revealed that SR-A interacted with and inhibited the phosphorylation of mitogen-activated protein kinase kinase 7, the major kinase in the RAGE-MAPK-NF-κB signaling, thereby leading to diminished secretion of proinflammatory cytokines. Our findings suggest that the antagonism between SR-A and RAGE contributes to the pathogenesis of DR by nurturing a disease-prone macrophage phenotype. Therefore, specific agonist that boosts SR-A signaling could potentially provide benefits in the prevention and/or intervention of DR.
The target of zero carbon society has a profound impact on economic transformation and energy structure adjustment. This paper proposes multi-energy nexus including electricity, gas, heat, and ...hydrogen in a district-integrated energy system (DIES), which detailedly refines the power-to-gas process via hydrogen energy utilization. Wind scenarios are generated and reduced with Latin hypercube sampling techniques. The minimal daily operating cost of DIES includes wind spillage cost and energy purchase cost, which is formulated as a mixed-integer linear programming problem. Simulation results under three different strategies have verified the rationality and feasibility of the proposed model.
Overall elastic-plastic stability behavior of cable-stayed ultra-high strength steel (660MPa) column with welded I-section is studied by geometric and material nonlinear FEM of software ANSYS. ...Longitudinal residual stresses and initial imperfections are taken into consideration. The results indicate that cable-stayed type can significantly improve overall stability bearing capacity and effectively control mid-span deflection of ultra-high strength steel column.
PDF
