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Background Chinese aging population degree will transform mild to moderate. During addressing aging issues by proactive national strategies and healthy aging strategies, the sleep health of older peoplecannot be ignored. Objective To explore the effect of working after retirement on sleep quality in Chinese older people, providing relevant reference data for improving sleep quality in this group of people. Methods In August 2021, data of working after retirement prevalence and sleep health in subjects aged ≥60 years (n=7 862) were obtained from the 2018 China Family Panel Studies (CFPS) conducted by Peking University with permission. They were divided into working after retirement and non-working after retirement groups by working after retirement prevalence. Normal sleep duration (within 4 to 10 hoursper night) , abnormal sleep duration (≤4 or ≥10 hours per night) , sleeping late (going to bed after 23 o'clock) in accordance with relevant diagnostic criteria used in international studies on sleep health in middle-aged and older people. Self-reported perceptions of sleep quality were classified into optimistic and pessimistic according to subjective evaluation of sleep efficiency and effect. Binary Logistic regression model was used to explore the effect of working after retirement on sleep duration, perception of sleep quality and the time to go to sleep. Results Among the subjects, 5 705 (72.56%) had optimistic sleep quality, 6 508 (82.78%) had normal sleep duration, and 7 464 (94.94%) went to sleep earlier than 23: 00, and 4 005 (50.94%) still worked after retirement. After controlling for age, gender, maritalstatus, education level, personality traits and other factors, working after retirement was associated with increased probability of higher optimism with sleep quality〔OR (95%CI) =1.205 (1.069, 1.358) 〕, more normal sleep duration〔OR (95%CI) =1.306 (1.137, 1.499) 〕, and earlier time to go to sleep〔OR (95%CI) =1.596 (1.253, 2.033) 〕.Working after retirement was associated with increased probability of good sleep quality (P

Classical frequency-stabilized lasers have achieved high-frequency stability and reproducibility; however, their extensive wavelength spacing limits their utility in various scenarios. This study introduces a novel frequency-stabilized laser scheme that integrates a Fabry-Perot etalon (FPE) with digital control technology and wavelength modulation techniques. The FPE, characterized by multiple transmission peaks at minimal frequency intervals, provides stable frequency references for different lasers, thereby enhancing the system's flexibility and adaptability. An error signal is derived from the first-order differentiation of the FPE's transmission curve. A 180° phase difference was observed in the feedback output signal when the laser's central frequency diverged from the reference, determining that the direction of the frequency control was accordingly determined.Employing feedback control, the laser's output frequency is stabilized at the transmission peak frequency of the FPE. Experimental results demonstrate that this stabilization scheme effectively locks the laser's output wavelength to different transmission peak frequencies of the FPE, achieving 25 GHz wavelength spacing. The frequency stability is improved by two orders of magnitude on a second-level timescale, maintained within hundreds of kHz, equating to a frequency stability level of 10−10. [ABSTRACT FROM AUTHOR]

Small-strain shear modulus (G) is an essential parameter for many geotechnical analyses. Most of shallow foundations are constructed in an unsaturated soil and the shear modulus of the unsaturated soil fluctuates because of the precipitation, evaporation, and rising of ground water table. In this paper, a new mathematical model is proposed for the estimation of the shear modulus function, Gunsat, which defines the relationship between small-strain modulus of unsaturated soil and matric suction. In the proposed model, the soil-water characteristic curve in the form of the degree of saturation is used as the input information. There are additional two parameters named n and C, which can be calibrated with the experimental data, are adopted in the proposed model. The estimated results show good agreement with the experimental data from literature. The proposed method can be used to track the tendency of Gunsat and minimize the data points from the laboratory tests. [ABSTRACT FROM AUTHOR]

This study analyzes the nonlinear seismic behavior of cluster-connected prefabricated shear walls under varying axial compression ratios. The investigation focuses on the connectivity of shear wall segments assembled using cluster connections rather than separate walls connected by beams. Using the finite element software ABAQUS, this study simulates monotonic horizontal displacement loading to evaluate the yield strength, peak strength, and deformation capacity of the shear walls. The results demonstrate that the horizontal load-bearing capacity of the shear wall significantly improves with an increase in axial compression ratio, while the axial compression ratio also influences ductility. The numerical simulations are validated against experimental data, confirming the accuracy of the model. These findings provide essential insights for optimizing the seismic design of precast shear walls. [ABSTRACT FROM AUTHOR]

The reinforced part at the bottom of high-rise assembled monolithic concrete shear wall structures generally uses cast-in-place concrete due to high elastic–plastic deformation capacity requirements, which limits the advantages of prefabricated shear wall structures. This study investigates the feasibility of using cluster connections to assemble integral shear wall structures at the bottom by modifying the vertical reinforcement of the cluster connection. Numerical simulations using ABAQUS (Version 2019) were validated with laboratory test results. The seismic performance of prefabricated shear walls with cluster connections was examined under varying axial compression ratios. Results indicate that the prefabricated shear wall demonstrates higher bearing and deformation capacity compared to cast-in-place shear walls. The degradation of strength and equivalent stiffness in prefabricated walls is slower, showing better seismic performance under higher axial compression ratios. The cluster connection ensures effective force transmission, maintaining wall integrity. After optimization, the prefabricated shear wall with cluster connection meets the expected seismic performance, providing a basis for its application in reinforced bottom sections. [ABSTRACT FROM AUTHOR]