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• It outlines the primary reasons for degradation, patterns of evolution, and research methods pertaining to the degradation of crucial materials in slab tracks. • It summarizes the distinct characteristics of structural issues and the dynamic performance evolution of slab tracks. • It explains the operational principles and application scope of structural diagnosis technologies. • The core scientific challenges and technical obstacles that require urgent attention in slab track development is elucidated. In the course of the long-term service of high-speed railway slab tracks, the diverse range of loading types and long-time characteristics can result in material property deterioration and structural damage. A precise understanding of the structural condition is essential for the scientific maintenance of the track. This paper offers an overview of material deterioration in slab tracks, the evolution of structural performance, and techniques to diagnose structural states. It outlines the primary reasons for degradation, patterns of evolution, and research methods pertaining to the degradation of crucial materials in slab tracks while summarizing the distinct characteristics of structural issues and the dynamic performance evolution of slab tracks. It explains the operational principles and application scope of structural diagnosis technologies before elucidating the core scientific challenges and technical obstacles that require urgent attention in slab track development. This paper establishes a robust theoretical and technical foundation for enhancing the quality and maintenance conditions of high-speed railways. [ABSTRACT FROM AUTHOR]

The detection of ballastless track surface (BTS) defects is a prerequisite for ensuring the safe operation of high-speed railways. Traditional convolutional neural networks fail to fully exploit contextual information and lack global pixel representations. The extensive stacking of convolutions leads deep learning models to play a black-box detection role, lacking interpretability. Due to the current lack of sufficient high-quality surface data for ballastless tracks, it is a severe constraint on the accurate identification of the substructure state in high-speed railways. This paper proposes an intelligent detection method for BTS defects named TrackNet based on self-attention and transfer learning. The method enhances the fusion ability of global features of BTS defects using multihead self-attention. The model's dependence on extensive defect data is reduced by transferring knowledge from large-scale publicly available datasets. Experimental results demonstrate that compared to advanced Swin Transformer model results, the TrackNet model achieves improvements in average accuracy and F1-score by 5.15% and 5.16%, respectively, on limited test data. The TrackNet model visualizes the decision regions of the model in identifying BTS defects, revealing the black-box recognition mechanism of deep learning models. This research performs engineering applications and provides valuable insights for the multiclass recognition of BTS defects in high-speed railways. [ABSTRACT FROM AUTHOR]

• Tensile and shear tests of composite concrete specimens were conducted. • CZM parameters were obtained using DIC technique. • A 3-D finite element model reflecting interface damage was established. • The effects of different cohesive parameters on the interface damage were analyzed. Debonding between the track slab and self-compacting concrete (SCC) is a common form of damage in China railway track system (CRTS) III prefabricated slab tracks. To investigate the influence of interlayer cohesive parameters on the interface connection, composite specimens of track slabs and SCC were made to be used for splitting tensile and shear tests. The variation characteristics between the interface's tension and displacement were obtained using digital image correlation (DIC) techniques, and the key parameters of a cohesive zone model (CZM) were determined and used to simulate the cracking behavior. Also analyzed was the interlayer damage behavior of the composite specimen using ABAQUS, the results of which were compared with those of the tests. Furthermore, a finite element simulation model of the CRTS III prefabricated slab track with CZM was used to analyze the impact of different cohesive parameters on interlayer damage under train loads and varying temperature gradient loads. The results show that: I). The DIC technique accurately describes the entire process from the damage initiation and propagation, to complete failure of the interface-bonded components; II). The finite element simulation results of the concrete composite specimens agree with the experimental results, indicating the CZM accurately reflects the interlayer cracking behaviors; III). Reducing the interface stiffness and increasing the critical fracture energy can slightly delay the onset of interface damage and debonding, respectively; IV). An increase in the cohesive strength can effectively inhibit the development of interface damage, for example, increasing the normal and tangential cohesive strength can improve the starting temperature gradient for interlayer damage initiation by 150 % and 45 %, respectively; and V). Under large positive temperature gradients (>70 °C/m), the interlayer debonding rate corresponding to most cohesive parameters reaches 100 % (complete failure of adhesion), making extreme temperature areas a necessary focus on the interlayer debonding of slab tracks. The research results of this paper can be used to analyze the damage behavior between the track slab and SCC layer, and provide a theoretical basis for the design and maintenance of CRTS III prefabricated slab track. [ABSTRACT FROM AUTHOR]

• The mechanical transfer relationship of uneven frost heave and slab track is revealed. • A full-scale temperature field test of the slab track is conducted. • The slab track's warping deformation and stress distribution under thermal load are analyzed. • The interlayer debonding and damage characteristics of the slab track due to multiple issues are investigated. To ensure the secure operation of high-speed trains in seasonally frozen regions, this paper investigates the deformation and failure patterns of slab tracks subjected to uneven frost heave and environmental issues. Utilizing our team's previous research findings, finite element analysis software was employed to construct a mechanical transfer calculation model for the subgrade and slab track. This model was used to explore the relationship between uneven frost heave and slab track deformation at different time periods, along with the track structure's damage behavior. In addition, comprehensive temperature field tests were conducted on the China railway track system (CRTS) III slab track, probing temperature variations, warping deformations, and stress distributions within the track structure. Finally, the interaction of uneven frost heave and thermal loads unveiled the interlayer debonding and stress characteristics of slab track structures across different months in seasonally frozen regions. The results revealed that the greater amplitude of frost heave and the smaller wavelength led to a higher change rate of rail irregularity. The uneven lateral deformation of the subgrade surface due to the sunny-shady slopes effect resulted in significant rail level irregularity of slab tracks. The combined impact of short-wavelength frost heave and temperature gradient loads emerged as the primary cause of macroscopic damage and stiffness degradation of concrete materials within slab track structures. These findings will help to understand the mechanical behavior of slab tracks in cold regions, thereby improving the quality of high-speed railway operations. [ABSTRACT FROM AUTHOR]

Background: To compare the right and left transthoracic approach on the post-operative survival of patients with lymph node-negative esophageal squamous cell carcinoma.Methods: Six hundred and ninety-five ESCC patients who underwent esophagectomy between 1990 and 2005 were retrospectively enrolled in the present study and were confirmed by histology to be of no lymph node metastasis. Those who had received neoadjuvant chemotherapy or radiotherapy were excluded from the study. Patients were divided into two groups, the left (n=545) and right (n=150) transthoracic groups. The follow-up duration ranged from 1 to 20 years with a mean of 7 years. Kaplan-Meier and univariate and multivariate Cox proportional hazards were used for analysis.Results: 3- and 5-year CSS rates were 62.0 % and 44.0 % in the left group, while the corresponding figures in the right group were 56.0 % and 40.0 %(P<0.05). The overall survival for the two groups was significantly different (P=0.045). Survival analyses were stratified by stages, which found that the favorable survival advantage was not present. When the survival curves were stratified by tumor locations, a significant difference was not revealed. Surgical approaches were regarded as one of the prognostic factors in the univariate analysis (P=0.019). However, this significance could not be confirmed in multivariate Cox regression analysis (P=0.193).Conclusions: The left transthoracic approach is superior in some aspects to the right transthoracic approach regarding surgical and oncological outcomes in the treatment of lymph node negative ESCC. [ABSTRACT FROM AUTHOR]