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Purpose: Goal for the present research is investigating the axisymmetric wave propagation behaviors of fluid-filled carbon nanotubes (CNTs) with low slenderness ratios when the nanoscale effects contributed by CNT and fluid flow are considered together. Method: An elastic shell model for fluid-conveying CNTs is established based on theory of nonlocal elasticity and nonlocal fluid dynamics. The effects of stress non-locality and strain gradient at nanoscale are simulated by applying nonlocal stress and strain gradient theories to CNTs and nonlocal fluid dynamics to fluid flow inside the CNTs, respectively. The equilibrium equations of axisymmetric wave motion in fluid-conveying CNTs are derived. By solving the governing equations, the relationships between wave frequency and all small-scale parameters, as well as the effects caused by fluid flow on different wave modes, are analyzed. Results: The numerical simulation indicates that nonlocal stress effects damp first-mode waves but promote propagation of second-mode waves. The strain gradient effect promotes propagation of first-mode waves but has no influence on second-mode waves. The nonlocal fluid effect only causes damping of second-mode waves and has no influence on first-mode waves. Damping caused by nonlocal effects are most affect on waves with short wavelength, and the effect induced by strain gradient almost promotes the propagation of wave with all wavelengths.

The suspension test-rig is restricted by the compound swing motion of the load wheel in a high-speed tracked vehicle, and cannot test the damping performance for the suspension system of the high-speed tracked vehicle with the track. A vibration damping testing mechanism using vertical linkage to decouple the compound swing motion of the load wheel is proposed for suspension performance testing with the track. Using Hertz elastic contact theory to solve the stiffness coefficient between load wheel and excitation wheel, a virtual prototype model for vibration damping test mechanism with vertical linkage is established in ADAMS. Correctness of the virtual prototype model is verified by experiment. The motion decoupling ability of the vibration damping testing mechanism is verified by simulation. The dynamic characteristics for each pair of guide and slider in vibration damping testing mechanism are analyzed under the condition of maximum excitation force and displacement, and the selection criteria of slider and guide contained in the motion pair components are acquired. The mechanism decouples the compound swing motion of the load wheel successfully, and can make suspension system performance testing in high-precision for the high-speed tracked vehicle with track realized, playing an important role in parameters design and performance optimization for the high-speed tracked vehicle.

China has been continuously improving its monitoring methods and strategies to address key infectious diseases (KIDs). After the severe acute respiratory syndrome epidemic in 2003, China established a comprehensive reporting system for infectious diseases (IDs) and public health emergencies. The relatively lagging warning thresholds, limited warning information, and outdated warning technology are insufficient to meet the needs of comprehensive monitoring for modern KIDs. Strengthening early monitoring and warning capabilities to enhance the public health system has become a top priority, with increasing demand for early warning thresholds, information, and techniques, thanks to constant innovation and development in molecular biology, bioinformatics, artificial intelligence, and other identification and analysis technologies. A panel of 31 experts has recommended a fourth-generation comprehensive surveillance system targeting KIDs (41 notifiable diseases and emerging IDs). The aim of this surveillance system is to systematically monitor the epidemiology and causal pathogens of KIDs in hosts such as humans, animals, and vectors, along with associated environmental pathogens. By integrating factors influencing epidemic spread and risk assessment, the surveillance system can serve to detect, predict, and provide early warnings for the occurrence, development, variation, and spread of known or novel KIDs. Moreover, we recommend comprehensive ID monitoring based on the fourth-generation surveillance system, along with a data-integrated monitoring and early warning platform and a consortium pathogen detection technology system. This series of considerations is based on systematic and comprehensive monitoring across multiple sectors, dimensions, factors, and pathogens that is supported by data integration and connectivity.This expert consensus will provides an opportunity for collaboration in various fields and relies on interdisciplinary application to enhance comprehensive monitoring, prediction, and early warning capabilities for the next generation of ID surveillance. This expert consensus will serve as a reference for ID prevention and control as well as other related activities.

ABSTRACTGiven the high level of exposure to SARS-CoV-2, cold-chain workers are considered priority vaccination groups. To date, many studies have reported on the willingness within distinct populations to be vaccinated against COVID-19, whereas it has not been reported among cold-chain workers worldwide. To address this void, we conducted a cross-sectional survey to gather general information, COVID-19-related knowledge, attitudes, and practices (KAP), and willingness to receive a COVID-19 vaccine among cold-chain workers in Shenzhen, China. Binary logistic analyses were conducted to explore the associations between COVID-19-related KAP factors and the willingness for COVID-19 vaccination. Among 244 cold-chain workers, 76% indicated that they were willing to be vaccinated. Knowledge about SARS-CoV-2, comprehending the most effective prevention, understanding the transmission routes, and recognizing the priority vaccination groups were positively associated with willingness to be vaccinated against COVID-19. Regarding attitude factors, perceiving the social harmfulness and severity of COVID-19 were related to a higher willingness to vaccination. Participants considering themselves a priority group for COVID-19 vaccination were more likely to get vaccinated. For practice factors, attaining more knowledge and higher self-reported compliance with maintaining adequate ventilation were also positively associated with the dependent variable. Agreement on the importance of COVID-19 vaccination was the most frequent reason for accepting the COVID-19 vaccine; additionally, concerns about side effects and insufficient understanding of efficacy were the main factors contributing to vaccine refusal. Enhancing KAP levels related to COVID-19 helps promote vaccine acceptance. Health authorities should promptly implement educational activities following the updated vaccine status among cold-chain workers.

ABSTRACTElderly individuals with chronic illnesses are more prone to get influenza. We aimed to investigate the factors associated with influenza coverage and willingness in chronic disease patients aged ≥60 years in Longhua district, Shenzhen City of southern China. Data collected in October 2020 were used in this work. The immunization status of older persons with chronic conditions and their willingness to receive the vaccine were assessed. Multivariable logistic regression was employed to determine the respective independent factors related to vaccination coverage and willingness for influenza. Only 4.8% of 5045 people were immunized against influenza, whereas 92.7% of the individuals agreed to receive the vaccine. Individuals between the ages of 70 and 79 (adjusted OR [aOR] 1.47, P = .012), those with higher education levels (aOR 1.53, P = .005 for high school; aOR 2.44, P < .001 for college or above), those who use of a family doctor (aOR 2.91, P < .001), those who frequently have physical examinations once a year (aOR 2.52, P < .001), and those who have never smoked (aOR 1.62, P = .018) were positively associated with the influenza vaccination. Meanwhile, older age was adversely linked with influenza vaccination willingness (aOR 0.68 for 70–79 years, P= .003; aOR 0.55 for≥80 years, P= .025) in contrast to those aged 60–69. High willingness to get vaccinated was more frequent in people with a high school diploma (aOR 1.33, P= .037). In this work, we observed that the coverage is poor but the immunization desire is high regarding influenza vaccination. Interestingly, older age was associated with higher coverage and lower willingness. These suggest that raising immunization rates among older people with chronic conditions and strengthening health education for caregivers should be the primary concerns.

In the study of electromechanical coupling vibration of mill main drive system, the influence of electrical system on the mechanical transmission is considered generally, however the research for the mechanism of electromechanical interaction is lacked. In order to research the electromechanical coupling resonance of main drive system on the F3 mill in a plant, the cycloconverter and synchronous motor are modeled and simulated by the MTLAB/SIMULINK firstly, simulation result show that the current harmonic of the cycloconverter can lead to the pulsating torque of motor output. Then the natural characteristics of the mechanical drive system are calculated by ANSYS, the result show that the modal frequency contains the component which is close to the coupling vibration frequency of 42Hz. According to the simulation result of the mechanical and electrical system, the closed loop feedback model including the two systems are built, and the mechanism analysis of electromechanical coupling presents that there is the interaction between the current harmonic of electrical system and the speed of the mechanical drive system. At last, by building and computing the equivalent nonlinear dynamics model of the mechanical drive system, the dynamic characteristics of system changing with the stiffness, damping coefficient and the electromagnetic torque are obtained. Such electromechanical interaction process is suggested to consider in research of mill vibration, which can induce strong coupling vibration behavior in the rolling mill drive system.