Search

To explore the correlation between college students’ social media behaviors and their mental health in the context of the network era in order to provide some empirical evidence for college students’ mental health education in the new period and new situation. In this paper, we first introduce the attention mechanism to optimize the LSTM network model to extract the features of college students’ online social media behaviors and combine it with the weighted cross-entropy cost function to improve the speed of the model when extracting behavioral features. Then, the fitness function of the genetic algorithm is used to analyze the distance between the feature samples, and the optimal features are selected through the selection strategy and cross-variance operation to obtain the college students’ online social media behavior. The analysis of the impact of social media behavior on mental health found that there is a significant difference in the level of misplaced fear and self-differentiation of students with different average use times of social media (P=0.024

Smart wearable ophthalmic devices such as contact lenses have gained widespread interest owing to their compactness, portability, and versatility and have emerged as the most promising, non‐invasive, wearable devices for the treatment and diagnosis of a variety of ocular diseases. While contact lenses for the treatment of congenital eye diseases such as color vision deficiency (CVD) are reported, they show limited spectral adjustment range and the unavailability of blocking harmful light such as high‐energy blue light (HEBL). In this study, silver nanoparticle (AgNP) based multifunctional contact lenses that can correct various types of CVDs and filter out harmful light are developed. AgNPs are controllably assembled via short‐peptide‐induced diffusion‐limited aggregation and then integrated into the contact lenses. By varying the sequence and concentration of the peptides, the extinction value of the nanoparticles can be broadly tuned in the 400–600 nm range. The multifunctional contact lenses thus show wide spectral tunability and are capable of efficiently correcting multiple CVDs and blocking HEBL. The contact lenses are found to have excellent biocompatibility with cell and animal tests. In conclusion, the multifunctional contact lenses provide a candidate for the correction of CVD and protection against HEBL, and pave the way for personalized wearable ophthalmic devices. [ABSTRACT FROM AUTHOR]

To reduce errors in sub-synchronous oscillation (SSO) modal identification and improve the accuracy and noise resistance of the traditional Prony algorithm, this paper focuses on SSOs caused by the integration of doubly fed induction generators (DFIGs) with series compensation into the grid. A novel SSO modal identification method based on the hippopotamus optimization–variational mode decomposition (HO-VMD) and singular value decomposition–regularized total least squares–Prony (SVD-RTLS-Prony) algorithms is proposed. First, the energy ratio function is used for real-time monitoring of the system to identify oscillation signals. Then, to address the limitations of the VMD algorithm, the HO algorithm's excellent optimization capabilities were utilized to improve the VMD algorithm, leading to preliminary denoising. Finally, the SVD-RTLS-improved Prony algorithm was employed to further suppress noise interference and extract oscillation characteristics, allowing for the accurate identification of SSO modes. The performance of the proposed method was evaluated using theoretical and practical models on the Matlab and PSCAD simulation platforms. The results indicate that the algorithms effectively perform denoising and accurately identify the characteristics of SSO signals, confirming its effectiveness, accuracy, superiority, and robustness against interference. [ABSTRACT FROM AUTHOR]

To optimize the crawling phenomenon of slides under circumstances of low speed and a heavy load, a composite lubrication structure is adopted to alleviate the crawling phenomenon. The response surface optimal-design method establishes a quadratic mathematical model for multistage composite lubrication structure parameters, including crawling time and average friction coefficient. The optimal combination parameters of multistage composite lubrication structures have been determined. The optimal ratio of lubricating oil to molybdenum disulfide (MoS2) has been identified, and a composite lubrication structure has been proposed to enhance the crawling phenomenon and friction performance of sliding guide rails under medium-speed and medium-load conditions. These research outcomes indicate that when low speed and a heavy load are present, the crawling time and friction coefficient initially diminish and subsequently augment as the width, spacing, and cycle length of the sinusoidal texture and the diameter of the hexagonal pit expand. The optimum configuration of multistage composite lubrication structures is as follows: The width of the sine-wave texture b amounts to 0.15 mm, the cycle length e is 2 mm, the spacing c is 1.5 mm, and the diameter of the hexagonal pit d is 0.2 mm. When the mass ratio of guide oil to MoS2 is 2:1, it exhibits supreme crawling resistance and antifriction attributes. In circumstances involving a medium load and speed, multistage composite lubrication structures manifest pre-eminent friction performance. These data can steer the design of multistage composite lubrication structures on the surface of slide rails. [ABSTRACT FROM AUTHOR]

The doubly fed variable speed pumped storage (DFVSPS) system is a hydraulically, mechanically, and electrically coupled system, and the characteristics of the components from the water conveyance system to the transmission line need to be fully considered in the oscillation analysis. Hence, the model of the water conveyance system is included to investigate the oscillation characteristics of the DFVSPS connecting to the grid via a series-compensated line. A small-signal state-space model of the DFVSPS system in the generation mode is first established. The oscillation characteristics of the DFVSPS are studied, and the dominant state variables for each oscillation mode are identified. The impact of system parameters on oscillations is further studied, and simulations are carried out to validate the accuracy of the model. The results indicate the oscillation mode of the DFVSPS comprises the electrical sub-synchronous oscillation (SSO) mode and the hydraulically, mechanically coupled low-frequency mechanical oscillation modes. When the series compensation level is high, the SSO becomes divergent, and the system is more likely to be unstable. Optimizing the rotor-side control parameters and the governor control parameters, sub-synchronous and low-frequency oscillations could be effectively suppressed, respectively. This study provides reference suggestions for the development and use of the future DFVSPS system. [ABSTRACT FROM AUTHOR]

With the continuous development of renewable energy worldwide, the issue of frequency stability in power systems has become increasingly serious. Enhancing the inertia level of power systems by configuring battery storage to provide virtual inertia has garnered significant research attention in academia. However, addressing the non-linear characteristics of frequency stability constraints, which complicate model solving, and managing the uncertainties associated with renewable energy and load, are the main challenges in planning energy storage for high-proportion renewable power systems. In this context, this paper proposes a battery storage configuration model for high-proportion renewable power systems that considers minimum inertia requirements and the uncertainties of wind and solar power. First, frequency stability constraints are transformed into minimum inertia constraints, primarily considering the rate of change of frequency (ROCOF) and nadir frequency (NF) indicators during the transformation process. Second, using historical wind and solar data, a time-series probability scenario set is constructed through clustering methods to model the uncertainties of wind and solar power. A stochastic optimization method is then adopted to establish a mixed-integer linear programming (MILP) model for the battery storage configuration of high-proportion renewable power systems, considering minimum inertia requirements and wind-solar uncertainties. Finally, through a modified IEEE-39 bus system, it was verified that the proposed method is more economical in addressing frequency stability issues in power systems with a high proportion of renewable energy compared to traditional scheduling methods. [ABSTRACT FROM AUTHOR]

Since the release of the Chinese sci-fi movie The Wandering Earth 2, it has caused a huge sensation. Its performance techniques, production process, and story content have all aroused extensive discussions, and it has been widely analyzed as a milestone of Chinese sci-fi movies. This article explores the industrial aesthetics of The Wandering Earth 2 and analyzes the background and factors that produced the film. The article believes that the success and breakthrough of The Wandering Earth 2 in the Chinese film market is mainly due to the continuous expansion of the Chinese film market, the mainstreaming of science fiction culture, the rise of national consciousness and the popularity of large-scale narratives. In terms of research method, using textual and comparative analysis, this paper explores five aspects of film industry aesthetics, namely: production process, visual effects, narrative structure, thematic meaning and social influence. This article believes that The Wandering Earth 2 is not only a sci-fi film that coexists with business and art, but more importantly, it reflects the value of Chinese culture’s expression and dissemination on a global scale, which has important historical significance and cultural status.

We investigate the magnetic and electronic properties of Co films on Fe3O4(001) achieved through epitaxial growth using magnetron sputtering. X-ray magnetic circularly dichroism measurements characterize the atomic magnetism. Compared to Co films on the MgO substrate, Co on Fe3O4 exhibits a 96% enhancement in orbital magnetic moment (from 0.25 to 0.49 µB/atom) and an increase in spin magnetic moment (from 1.37 to 1.53 µB/atom), resulting in an increased mratio(ml/ms) from 0.18 to 0.32. This enhancement of the orbital moment emerges as a consequence of the interface interaction between Co and Fe3O4. Density functional theory calculations attribute this heightened orbital magnetic moment to the robust electronic exchange interactions. Our findings not only offer insights into the modulation of magnetic and electronic characteristics in Co-based magnetic heterostructures but also provide valuable implications for the potential application of magnetic oxide/ferromagnetic heterostructures in future spintronic devices. [ABSTRACT FROM AUTHOR]