Search

To evaluate the crack sensitivity of Q350EW high-chromium weathering resistant steel during continuous cast⁃ ing， the high-temperature thermoplastic characteristics of Q350EW high-chromium weathering resistant steel were studied using Gleeble3500 thermal simulation testing machine， and the distribution of precipitates in the steel was calculated us⁃ ing Thermo-Calc thermodynamic software. Scanning electron microscopy and optical microscopy were used to observe and analyze the macrostructure and microstructure morphology of high-temperature tensile fractures and microstructure at the fractures. The research results indicate that as the heating temperature increases， the tensile strength of the test steel de⁃ creases； The cross-sectional shrinkage curve shows a concave valley around 700 ℃-800 ℃， with the lowest cross-sectional shrinkage of 64. 9% at 775 ℃. The fracture morphology within the range of concave valley temperature is mainly composed of ductile dimples， and its fracture mechanism is ductile fracture. Microscopic analysis shows that ferrite appears at the grain boundaries of the original austenite， leading to a decrease in plasticity. However， due to the high content of ferrite， the plasticity of Q350EW high chromium weather resistant steel still remains at a high level. By optimizing key process pa⁃ rameters such as secondary cooling during continuous casting， the risk of cracking in Q350EW high chromium weather re⁃ sistant steel billets can be reduced. It is recommended that the temperature of the corner bending and straightening section of the billets be less than 750 ℃.

Objective To study the optimization measures for treating waterlogged collapsible loess stratum, it is necessary to investigate the deformation characteristics of tunnel structures after loess collapse by waterlogging. Method The foundation treatment for the waterlogged collapsible loess tunnels is introduced. Taking a shield metro tunnel crossing through waterlogged collapsible loess stratum as example, the method of three-axis mixing pile is adopted as the foundation treatment method. By establishing a numerical calculation model using MIDAS GTS software， the influence of waterlogged deformation of loess foundation on the vertical displacement of various metro tunnel structure parts and the internal force of lining structure is analyzed under different treatment depths and treatment widths. The treatment scheme is optimized based on the changing trends of tunnel parts vertical displacement and lining structure internal force, the construction economy and relevant requirements. Under conditions of three treatment widths and seven treatment depths, variation laws of vertical displacement, bending moment, and principal stress at the tunnel arch waist, vault, and invert are analyzed for the most suitable treatment recommendation. Result & Conclusion The greater the treatment depth, the smaller the vertical displacement of tunnel structure parts and the larger the lining structure internal force; the larger the treatment width, the smaller the vertical displacement and the internal force mentioned above. In this case study engineering, the optimal treatment depth is 7 m, and the optimal treatment width is 16 m.

Background The hypertensive population has a large base in China, and its preventive and treatment measures rely mainly on the chronic disease management service program within the National Basic Public Health Service. However, current studies have shown low utilization rate of it, so it is of great significance for improving the participation of the National Chronic Disease Management Service and health level in the hypertensive population to conduct a survey of participants to determine the factors affecting their treatment adherence. Objective To investigate and analyze the current status and influencing factors of treatment adherence of hypertension management services within the National Basic Public Health Service, and provide reference for improving treatment adherence in hypertensive patients. Methods A total of 295 participants of hypertension management services in the community served by a community healthcare center in Guangzhou City from June to September 2022 as the study subjects by using a multi-stage sampling method. The General Information Questionnaire and the Emotional Balance Scale (positive and negative emotions) were used to investigate the basic information of the study subjects, and the Hypertension Treatment Adherence Scale was used to investigate the current status of treatment adherence among the study subjects. Multivariate Logistic regression analysis was used to explore the influencing factors of treatment adherence to the National Chronic Disease Management Service in the hypertensive population, and the influence of the combined positive and negative emotion status on treatment adherence to the National Chronic Disease Management Service in the hypertensive population. Results A total of 310 valid questionnaires were distributed, 295 valid questionnaires were recovered, with a validity rate of 95.2%; the total score of the Hypertension Treatment Adherence Scale was (94.24±8.67), of which the score of medication adherence was (21.06±2.45), medication malpractice was (31.33±3.90), tobacco and alcohol management was (8.44±1.88), and management of daily life was (33.41±4.61), with good adherence rate of 52.2% (154/295) ; the positive emotion score in the Emotional Balance Scale was (3.76±1.02), and the negative emotion score was (2.63±1.12) ; the results of multivariate Logistic regression analysis showed that gender, age, BMI, education level, blood pressure control, self-perceived physical condition, satisfaction with the point of care, more positive emotions and less negative emotions were the influencing factors for good treatment adherence to the National Chronic Disease Management Service in the hypertensive population (P

In this study, an aluminate coupling agent (ACA) was utilized to modify calcium carbonate (CaCO₃) particles, producing modified CaCO₃ (Al-CaCO₃) particles, which were subsequently employed as inorganic fillers to enhance the toughness of polylactide (PLA). PLA/Al-CaCO₃ composites were prepared through melt mixing, with the reaction between ACA and CaCO₃ confirmed by Fourier transform infrared (FTIR) spectroscopy. The mechanical, thermal, and biodegradation properties of these composites were thoroughly investigated. The addition of Al-CaCO₃ significantly enhanced the mechanical properties, with impact strength reaching approximately 9.7 kJ/m2, a 143% increase compared to neat PLA. The elongation at break also improved dramatically, rising from 7.5 to 34%, representing a 350% increase over neat PLA. Al-CaCO₃ particles demonstrated good dispersibility and strong interfacial interaction within the PLA matrix. Differential scanning calorimetry (DSC) results showed that Al-CaCO₃ enhanced the crystallization behavior of PLA, promoting the formation of more perfect crystals. Additionally, biodegradation tests revealed that the PLA/Al-CaCO₃ composites exhibited excellent biodegradation properties. The combined toughening and biodegradation properties of PLA/Al-CaCO₃ broaden the potential applications of PLA. [ABSTRACT FROM AUTHOR]