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The main research problem is the relationship between the use motivation (UM) and use behavior (UB) of middle-aged and old short videos users and the difference of the influence of the use motivation of middle-aged and old users, a special group, on the usage behavior is analyzed.

By means of a questionnaire survey and in-depth interview, the middle-aged and old-aged users' short video use motivation and behavior and their influence relationship are discussed.

It is found that information appeal is the main motivation of middle-aged and old-aged users to use short videos and users with different social attributes have differences in motivation and there is a significant relationship between motivation and behavior.

The research objective is middle-aged and elderly short video users. And how to promote the transformation of middle-aged and old-aged users' use mentality and record and create their unique bright spots in the big stage of short videos with a more active and independent attitude, is of unique significance not only to the users themselves but also to the media content of this era and the users' existence in the technological change.

This research aims to discover the relationship between social media usage (SMU) and the critical thinking ability (CTA) of university students, and to answer the question that whether social media dependence (SMD) affects the development of CTA, and thus providing a reference for the social media access strategy of academic libraries from the perspective of media information literacy.

The research data were collected via 300 valid questionnaires whose respondents are students from three universities in China. Multistage stratified cluster sampling method was used to select the respondents, which guarantees statistical representativeness. A pre-test was conducted to ensure the validity of the questionnaire.

It is shown that the total score of CTA and the six sub-dimensions are significantly positively correlated with SMU, but strongly negatively correlated with SMD. Based on the mediating effect testing, it is discovered that the degree of SMD can affect the promoting relations between the usage intensity of social media (UISM) and CTA. Clearly, SMU is a double-edged sword. While it narrows the digital gap in terms of accessibility, it widens the digital gap in terms of usage.

The differences in SMU have a significant impact on the development of CTA of university students. This inspires us to consider the ability of “using social media in a balanced way” as an important evaluation and training direction when inquiring media literacy. As social media is becoming a critical channel in cultivating individual's thinking skills, it is highly suggested that the amount of time spent on reading fragmented information on the internet should be controlled.

The paper aims to elucidate effective strategies for promoting the adoption of green technology innovation within the private sector, thereby enhancing the value of public–private partnership (PPP) projects during the operational phase.

Utilizing prospect theory, the paper considers the government and the public as external driving forces. It establishes a tripartite evolutionary game model composed of government regulators, the private sector and the public. The paper uses numerical simulations to explore the evolutionary stable equilibrium strategies and the determinants influencing each stakeholder.

The paper demonstrates that government intervention and public participation substantially promote green technology innovation within the private sector. Major influencing factors encompass the intensity of pollution taxation, governmental information disclosure and public attention. However, an optimal threshold exists for environmental publicity and innovation subsidies, as excessive levels might inhibit technological innovation. Furthermore, within government intervention strategies, compensating the public for their participation costs is essential to circumvent the public's “free-rider” tendencies and encourage active public collaboration in PPP project innovation.

By constructing a tripartite evolutionary game model, the paper comprehensively examines the roles of government intervention and public participation in promoting green technology innovation within the private sector, offering fresh perspectives and strategies for the operational phase of PPP projects.

Subway systems are highly susceptible to external disturbances from emergencies, triggering a series of consequences such as the paralysis of the internal network transportation functions, causing significant economic and safety losses to cities. Therefore, it is necessary to analyze the factors affecting the resilience of the subway system to reduce the impact of disaster incidents.

Using the interval type-2 fuzzy linguistic term set and the K-medoids clustering algorithm, this paper improves the Decision-Making Trial and Evaluation Laboratory (DEMATEL) method to construct a subway resilience factor analysis model for emergencies. Through comparative analysis, this study confirms the superior performance of the proposed approach in enhancing the precision of the DEMATEL method.

The results indicate that the operation and management level of emergency command organizations is the key resilience factors of subway operations in China. Furthermore, based on real case analyses, the corresponding suggestions and measures are put forward to improve the overall operation resilience level of the subway.

This paper identifies four emergency scenarios and 15 resilience factors affecting subway operations through literature review and expert consultation. The improved fuzzy DEMATEL method is applied to explore the levels of influence and causal mechanisms among the resilience factors of the subway system under the four emergency scenarios.

The car body stiffness of express freight sliding side covered wagon decreased for the sliding and the resonance vibration based on the flexible car body has affected the dynamics performances. Dynamic loading will cause fatigue cracks and eventually lead to fatigue failure of the car body. This paper aims to investigate the influence of car body flexibility on the evaluation of the failure.

In this paper, the railway vehicles random analysis procedure (RVRAP) is employed to study the fatigue failure of the rigid-flexibility model. Following the analysis process, the rigid-flexibility model is established and four contrastive schemes for simulation analysis are designed. To verify the results, an experimental test using the real car body structure on the vibration test plant is carried out; the RMS of dynamic stress is obtained and compared with the simulation results.

The results show that the flexibility of the car body has a crucial influence on the fatigue life.

The reliability is verified regarding the use of RVRAP at an appropriate stage on the antifatigue design of the vehicle.

According to relevant research, non-uniform speed has a significant impact on the vehicle-track systems. Up to now, research work on it is still very limited. In this paper, the PEM is adopted to further transform it into a deterministic process to solve the vehicle’s problem of running at a non-uniform speed.

The multi-body vehicle model has 10 degrees of freedom and the track is regarded as a finite long beam supported by lumped sleepers and ballast blocks. They are connected via linear Hertz springs. The vertical track irregularity is a Gaussian stationary process in the space domain. It is transformed into a uniformly modulated nonstationary random process in the time domain with respect to the non-uniform vehicle speed. By solving the equation of motion of the coupled vehicle-track system with the pseudo-excitation method, the pseudo-response and consequently the power spectral density and the standard deviation of the structural response can be obtained.

Two kinds of vehicle braking programs are taken in the numerical example and some beneficial conclusions are drawn.

The pseudo-excitation method (PEM) was used to perform the random vibration analysis of a coupled non-uniform speed vehicle-track system. Transforming the track irregularity into a uniformly modulated nonstationary random process in time domain with respect to the non-uniform vehicle speed was undertaken. The pseudo-response of the coupled system is solved by applying the Newmark algorithm with constant space integral steps. The random vibration transfer mechanism of the coupled system is fully discussed.

Under the carbon regulation mechanism, managing operational strategies is a challenging task. Green innovation is introduced into a hybrid system of manufacturing and remanufacturing to handle the carbon emission constraints in a dynamic market environment. This paper aims to investigate the joint dynamic green innovation policy and pricing strategies in a hybrid manufacturing and remanufacturing system.

This paper first considers a monopolistic manufacturer who offers brand-new products and remanufactured items at the same price to consumers. Subsequently, the authors extend their analyses to distinct pricing strategies for both newly manufactured products and refurnished ones in such a hybrid system. Two different cases are considered: a loose carbon emission constraint and a binding carbon emission constraint. By solving the dynamic optimization problem, the differential game and Pontryagin’s maximum principle are used to obtain the joint green innovation and pricing strategies.

The retail price first increases then declines over a single period. The green innovation diminishes in the same pricing decision model, while it first increases then declines in a distinct pricing decision model over a single planning horizon. The green innovation investment as well as the retail price are discouraged by an emission cap and recycling fraction. The distinct retail price fluctuates violently, and they are, in descending order of the highest peak price as follows: the newly manufactured product, the same pricing product and the repaired product. Carbon emission caps that are either too high or too low decrease the revenue of the manufacturer. A small emission constraint margin benefits the manufacturer. The recycling policy, as well as other parameters, affects whether the hybrid system attains the carbon emission constraint or not, which suggests that the recycling policy is complementary to the carbon emission constraint mechanism in the hybrid system.

These results offer managerial implications to the hybrid system in terms of green innovation, pricing strategies and recycling policy.

This paper is among the first papers to research the joint dynamic green innovation policy and pricing strategies with/without a carbon emission constraint in a hybrid manufacturing and remanufacturing system with a differential game. Moreover, this paper presents a potential way of investigating other common resource constraints by a differential game in a manufacturing/remanufacturing system or closed loop supply chain.

The purpose of this paper is to explore the threshold effect of firm size on technological innovation using panel data from 2007 to 2012 for listed enterprises in China's manufacturing sector.

Considering the aim of research question is to examine the nonlinear relationship, this paper utilizes the threshold regression proposed by Hansen's (2000).

Based on a threshold regression model using panel data from 2007 to 2012 for listed enterprises in China's manufacturing sector, we find a series of new results. This nonlinear relationship is under the restrictions and impacts of various factors, such as industry characteristics and government subsidies. The results suggest that the threshold regression model well explains the complicated nonlinear relationship and transition process, and it can also shed light on management practice and policy.

There are categorical arguments regarding why firm size is not as effective as before in explaining the monotonic principle of industrial innovation, especially for establishing an effective industrial policy in a particular situation. One of the important reasons is that we have begun to adopt a new perspective from the nonlinear view on the relationship between firm size and industrial innovation. In this study, we have examined the threshold effect of firm size on industrial technological innovation, which is the most representative nonlinear relationship.

The purpose of this paper is to propose an improved method which can shorten the calculation time and improve the calculation efficiency under the premise of ensuring the calculation accuracy for calculating the response of dynamic systems with periodic time-varying characteristics.

An improved method is proposed based on Runge–Kutta method according to the composition characteristics of the state space matrix and the external load vector formed by the reduction of the dynamic equation of the periodic time-varying system. The recursive scheme of the holistic matrix of the system using the Runge–Kutta method is improved to be the sub-block matrix that is divided into the upper and lower parts to reduce the calculation steps and the occupied computer memory.

The calculation time consumption is reduced to a certain extent about 10–35% by changing the synthesis method of the time-varying matrix of the dynamics system, and the method proposed of paper consumes 43–75% less calculation time in total than the original Runge–Kutta method without affecting the calculation accuracy. When the ode45 command that implements the Runge–Kutta method in the MATLAB software used to solve the system dynamics equation include the time variable which cannot provide its specific analytic function form, so the time variable value corresponding to the solution time needs to be determined by the interpolation method, which causes the calculation efficiency of the ode45 command to be substantially reduced.

The proposed method can be applied to solve dynamic systems with periodic time-varying characteristics, and can consume less calculation time than the original Runge–Kutta method without affecting the calculation accuracy, especially the superiority of the improved method of this paper can be better demonstrated when the degree of freedom of the periodic time-varying dynamics system is greater.

To address the lack of data in this field and determine the relationship between the coefficient of friction and the interference between locomotive wheels and axles, this study evaluates the theoretical relationship between the coefficient of friction and the interference under elastic deformation.

When using numerical analyses to study the mechanical state of the contacting components of the wheels and axle, the interference between the axle parts and the coefficient of friction between the axle parts are two important influencing factors. Currently, as the range of the coefficient of friction between the wheel and axle in interference remains unknown, it is generally considered that the coefficient of friction is only related to the materials of the friction pair; the relationship between the interference and the coefficient of friction is often neglected.

A total of 520 press-fitting experiments were conducted for 130 sets of wheels and axles of the HXD2 locomotive with 4 types of interferences, in order to obtain the relationship between the coefficient of friction between the locomotive wheel and axle and the amount of interference. These results are expected to serve as a reference for selecting the coefficient of friction when designing axle structures with the rolling stock, research on the press-fitting process and evaluations of the fatigue life.

The study provides a basis for the selection of friction coefficient and interference amount in the design of locomotive wheels and axles.