Research on the development and testing methods of physical education and agility training equipment in universities.

Introduction: Because of the problems of insufficient funds and traditional training methods in college sports agile training, an agile training system based on a wireless ad hoc network was developed to evaluate the effect of improving the sensitive quality of ordinary college students. Based on the ESP-MESH network, the lower computer realizes automatic networking between devices and tests the performance of the mesh network. Fourteen male college students received 9 weeks of agility training, with seven students in each of two groups: traditional agility training and agile equipment training. The researchers evaluated the performance of both groups in rapid disguise, body coordination, changing movements, and predictive decision-making. Results: There was no significant difference between the groups before training, but there were significant differences in the four abilities after training (p < 0.01). The experimental group had significant differences in rapid direction change and physical coordination (p < 0.05), and in changing movement and predictive decision-making ability (p < 0.01). Conclusion: Both traditional training and agile equipment training improve the agility quality of college students, and the latter shows better results in certain abilities. However, limited by other physical qualities, the improvement of motor changes and predictive decision-making ability is not as obvious as the other two abilities.

Direct observation of spreading precursor liquids in a corner.

Precursor liquid is a nanoscale liquid creeping ahead of the macroscopic edge of spreading liquids, whose behaviors tightly correlate with the three-phase reaction efficiency and patterning accuracy. However, the important spatial-temporal characteristic of the precursor liquid still remains obscure because its real-time spreading process has not been directly observed. Here, we report that the spreading ionic liquid precursors in a silicon corner can be directly captured on video using in situ scanning electron microscopy. In situ spreading videos show that the precursor liquid spreads linearly over time ([Formula: see text]) rather than obeying the classic Lucas-Washburn law ([Formula: see text]) and possesses a characteristic width of ∼250-310 nm. Theoretical analyses and molecular dynamics simulations demonstrate that the unique behaviors of precursor liquids originate from the competing effect of van der Waals force and surface energy. These findings provide avenues for directly observing liquid/solid interfacial phenomena on a microscopic level.

Shape optimization of a meniscus-adherent nanotip.

A soluble tip can dissolve into a tip with curvature when partially immersed in a liquid. This process has been used in the manufacture of sophisticated tips. However, it is difficult to observe the dissolution process in the laboratory, and the dissolution mechanisms at the nanoscale still need to be better understood. Here we utilize molecular dynamics simulations to study the dissolution process of a meniscus-adherent nanotip. The tip apex curvature radius reaches its minimum in the intermediate state. The shape of this state is defined as the optimized shape, which can be used as the termination criterion in applications. In addition, the shape of one optimized tip can be well-fitted to a double-Boltzmann function. The upper Boltzmann curve of this function forms via the competition between the chemical potential influence and the intermolecular forces, while the formation of the lower Boltzmann curve is controlled by the chemical potential influence. The parameters of the double-Boltzmann function are strongly correlated with the nanotip's initial configuration and dissolubility. A shape factor ξ is proposed to characterize the sharpness of optimized tips. Theory and simulations show that optimized tips possess a greater ability to shield the capillary effect than common tips. Our findings elucidate the meniscus-adherent nanotip's dissolution process and provide theoretical support for nano-instrument manufacture.

Soil Nitrogen Content Detection Based on Near-Infrared Spectroscopy.

Traditional soil nitrogen detection methods have the characteristics of being time-consuming and having an environmental pollution effect. We urgently need a rapid, easy-to-operate, and non-polluting soil nitrogen detection technology. In order to quickly measure the nitrogen content in soil, a new method for detecting the nitrogen content in soil is presented by using a near-infrared spectrum technique and random forest regression (RF). Firstly, the experiment took the soil by the Xunsi River in the area of Hubei University of Technology as the research object, and a total of 143 soil samples were collected. Secondly, NIR spectral data from 143 soil samples were acquired, and chemical and physical methods were used to determine the content of nitrogen in the soil. Thirdly, the raw spectral data of soil samples were denoised by preprocessing. Finally, a forecast model for the soil nitrogen content was developed by using the measured values of components and modeling algorithms. The model was optimized by adjusting the changes in the model parameters and Gini coefficient (∆Gini), and the model was compared with the back propagation (BP) and support vector machine (SVM) models. The results show that: the RF model modeling set prediction R2C is 0.921, the RMSEC is 0.115, the test set R2P is 0.83, and the RMSEP is 0.141; the detection of the soil nitrogen content can be realized by using a near-infrared spectrum technique and random forest algorithm, and its prediction accuracy is better than that of the BP and SVM models; using ∆ Gini to optimize the RF modeling data, the spectral information of the soil nitrogen content can be extracted, and the data redundancy can be reduced effectively.

Nanomaterials Facilitating Conversion Efficiency Strategies for Microbial CO2 Reduction.

Microbial electro- and photoelectrochemical CO2 reduction represents an opportunity to tackle the environmental demand for sustainable fuel production. Nanomaterials critically impact the electricity- and solar-driven microbial CO2 reduction processes. This minireview comprehensively summarizes the recent developments in the configuration and design of nanomaterials for enhancement of the bacterial adhesion and extracellular electron transfer (EET) processes, based on the modification technologies of improving chemical stability, electrochemical conductivity, biocompatibility, and surface area. Furthermore, the investigation of incorporating non-photosynthetic microorganisms using advanced light-harvesting nanostructured photoelectrodes for solar-to-chemical conversion, as well as the current understanding of EET mechanisms occurring at photosynthetic semiconductor nanomaterials-bacteria biohybrid interface is detailed. The crucial factors influencing the performance of microbial CO2 reduction systems and future perspectives are discussed to provide guidance for the realization of their large-scale application.

Enhanced transmembrane electron transfer in Shewanella oneidensis MR-1 using gold nanoparticles for high-performance microbial fuel cells.

Low efficiency of extracellular electron transfer (EET) is a major bottleneck in developing high-performance microbial fuel cells (MFCs). Herein, we construct Shewanella oneidensis MR-1@Au for the bioanode of MFCs. Through performance recovery experiments of mutants, we proved that abundant Au nanoparticles not only tightly covered the bacteria surface, but were also distributed in the periplasm and cytoplasm, and even embedded in the outer and inner membranes of the cell. These Au nanoparticles could act as electron conduits to enable highly efficient electron transfer between S. oneidensis MR-1 and electrodes. Strikingly, the maximum power density of the S. oneidensis MR-1@Au bioanode reached up to 3749 mW m-2, which was 17.4 times higher than that with the native bacteria, reaching the highest performance yet reported in MFCs using Au or Au-based nanocomposites as the anode. This work elucidates the role of Au nanoparticles in promoting transmembrane and extracellular electron transfer from the perspective of molecular biology and electrochemistry, while alleviating bottlenecks in MFC performances.

Perovskite-Based Multifunctional Cathode with Simultaneous Supplementation of Substrates and Electrons for Enhanced Microbial Electrosynthesis of Organics.

Microbial electrosynthesis (MES) is an electricity-driven technology for the microbial reduction of CO2 to organic commodities. However, the limited solubility of CO2 in a solution and the inefficient electron transfer make it impossible for microorganisms to obtain an efficient surface for catalytic interaction, thus resulting in the low efficiency of MES. To address this, we introduce a multifunctional perovskite-based cathode material Pr0.5(Ba0.5Sr0.5)0.5Co0.8Fe0.2O3-δ-carbon felt (Pr0.5BSCF-CF), which provides a simultaneously significant increase in CO2 absorption and hydrogen production. As a result, the volumetric acetate production rate of MES obtained by Pr0.5BSCF-CF is 0.24 ± 0.01 g L-1 day-1, and it achieves a maximum acetate titer of 13.74 ± 0.20 g L-1 within 70 days. An adequate supply of CO2 and H2 also provides a sufficient amount of substrates and energy for the self-replication of the biocatalysts in the MES reactor. This effect not only increases the amount of biocatalysts but also optimizes the functions of the biocatalysts; the above benefits further improve the production efficiency of the MES system. This strategy demonstrates that the development of perovskite-based multifunctional cathodes with a simultaneous supplementation of substrates and electrons is a promising approach toward improving the MES efficiency.

Mo2C-induced hydrogen production enhances microbial electrosynthesis of acetate from CO2 reduction.

BACKGROUND: Microbial electrosynthesis (MES) is a biocathode-driven process, in which electroautotrophic microorganisms can directly uptake electrons or indirectly via H2 from the cathode as energy sources and CO2 as only carbon source to produce chemicals. RESULTS: This study demonstrates that a hydrogen evolution reaction (HER) catalyst can enhance MES performance. An active HER electrocatalyst molybdenum carbide (Mo2C)-modified electrode was constructed for MES. The volumetric acetate production rate of MES with 12 mg cm-2 Mo2C was 0.19 ± 0.02 g L-1 day-1, which was 2.1 times higher than that of the control. The final acetate concentration reached 5.72 ± 0.6 g L-1 within 30 days, and coulombic efficiencies of 64 ± 0.7% were yielded. Furthermore, electrochemical study, scanning electron microscopy, and microbial community analyses suggested that Mo2C can accelerate the release of hydrogen, promote the formation of biofilms and regulate the mixed microbial flora. CONCLUSION: Coupling a HER catalyst to a cathode of MES system is a promising strategy for improving MES efficiency.

Fluidized granular activated carbon electrode for efficient microbial electrosynthesis of acetate from carbon dioxide.

The electricity-driven bioreduction of carbon dioxide to multi-carbon organic compounds, particularly acetate, has been achieved in microbial electrosynthesis (MES). MES performance can be limited by the amount of cathode surface area available for biofilm formation and slow substrate mass transfer. Here, a fluidized three-dimensional electrode, containing granular activated carbon (GAC) particles, was constructed via MES. The volumetric acetate production rate increased by 2.8 times through MES with 16 g L-1 GAC (0.14 g L-1 d-1) compared with that of the control (no GAC), and the final acetate concentration reached 3.92 g L-1 within 24 days. Electrochemical, scanning electron microscopy, and microbial community analyses suggested that GAC might improve the performance of MES by accelerating direct and indirect (via H2) electron transfer because GAC could provide a high electrode surface and a favorable mass transport. This study attempted to improve the efficiency of MES and presented promising opportunities for MES scale-up.