With the rapid development of micro/nanofabrication technologies, the concept of transformable kirigami has been applied for device fabrication in the microscopic world. However, most nano-kirigami ...structures and devices were typically fabricated or transformed at fixed positions and restricted to limited mechanical motion along a single axis due to their small sizes, which significantly limits their functionalities and applications. Here, we demonstrate the precise shaping and position control of nano-kirigami microrotors. Metallic microrotors with size of ~10 micrometers were deliberately released from the substrates and readily manipulated through the multimode actuation with controllable speed and direction using an advanced optoelectronic tweezers technique. The underlying mechanisms of versatile interactions between the microrotors and electric field are uncovered by theoretical modeling and systematic analysis. This work reports a novel methodology to fabricate and manipulate micro/nanorotors with well-designed and sophisticated kirigami morphologies, providing new solutions for future advanced optoelectronic micro/nanomachinery.
This study optimizes the modification and granulation of fly ash to make it more stable at the sediment–water interface. Through laboratory simulations, the modified fly ash pellets were optimally ...granulated to cover the sediment–water interface, and its control effect and mechanism were evaluated. The results showed that the phosphorus adsorption effect of lanthanum-modified fly ash was 34% and 40% higher compared with those of acid-modified and alkali-modified fly ash, respectively, with the phosphorus adsorption effect reaching 85%. The best dosing ratio was about 0.3 g/L. Adsorption was affected by pH and was more effective under weak alkalinity, close to the Langmuir adsorption model, which was consistent with the unimolecular layer adsorption characteristics and the presence of chemisorption and physical adsorption. The saturation adsorption amount of phosphate by lanthanum-modified fly ash was 8.89 mg/g. The optimized granulation conditions for lanthanum-modified fly ash pellets were a fly ash/montmorillonite ratio of 7:3, a roasting temperature of 900 °C, a roasting time of 4 h, and a particle size of 3 mm. After 20 days, the orthophosphate removal rate was more than 60% higher than that of the control group, with a total phosphorus removal rate of 43%. After covering for 60 days, active phosphorus in the surface layer of the sediment was gradually transformed into a stable phosphorus form, with calcium phosphorus accounting for 70% of the total inorganic phosphorus. The ability of the sediment to release phosphorus to the overlying water body was also significantly weakened. Meanwhile, the total phosphorus removal rate in the overlying water at the sediment–water interface reached more than 40%, and orthophosphate removal reached more than 60%, indicating an obvious phosphorus control effect. Transmission electron microscopy analysis showed that lanthanum was present at locations enriched with elemental phosphorus and was adsorbed onto the material surface. Therefore, lanthanum-modified fly ash pellets are a promising in situ phosphorus control agent with good endogenous phosphorus pollution control abilities in eutrophic water bodies.
Microfluidic methods for studying cell invasion can be subdivided into those in which cells invade into free space and those in which cells invade into hydrogels. The former techniques allow ...straightforward extraction of subpopulations of cells for RNA sequencing, while the latter preserve key aspects of cell interactions with the extracellular matrix (ECM). Here, we introduce "cell invasion in digital microfluidic microgel systems" (CIMMS), which bridges the gap between them, allowing the stratification of cells on the basis of their invasiveness into hydrogels for RNA sequencing. In initial studies with a breast cancer model, 244 genes were found to be differentially expressed between invading and noninvading cells, including genes correlating with ECM-remodeling, chemokine/cytokine receptors, and G protein transducers. These results suggest that CIMMS will be a valuable tool for probing metastasis as well as the many physiological processes that rely on invasion, such as tissue development, repair, and protection.
The polyvinyl chloride (PVC) ultrafine fibrous membranes were prepared by electrospinning. After solvent and thermal treatments, the membranes were used for the adsorption of cationic dye. The ...factors, the solvent ratio, the time of solvent treatment and the temperature of thermal treatment, were studied to enhance the mechanical properties of the membranes. The effects of the initial dye concentration and the solution temperature on the adsorption behaviors of the membranes were investigated. The results indicate that, long and uniform PVC ultrafine fibers were steadily electrospun at the PVC concentration of 10 w/v% in the mixture solvents of THF and DMF. The highest tensile strength of membranes reached 7.87 MPa, whereas the value of untreated counterpart was only 0.67 MPa. The equilibrium sorption capacity Qe increased with the increases of the initial dye concentration and solution temperature. The equilibrium adsorption of the membranes followed Freundlich isotherm and the adsorption kinetics observed Lagergren's pseudo-second order equation.
This work reports the use of optoelectronic tweezers (OET) and freeze-drying to assemble a variety of micro-/nano- materials into topographical micro-patterns, which can be transferred on to ...alternative substrates. It is demonstrated that polystyrene microparticles, metallic microparticles and graphene nanosheets can be assembled into fine micro-patterns with high precision and the assembled micro-patterns can be well preserved on the surface of OET device after removing the liquid medium via freeze-drying. The assembled micro-patterns can be transferred onto different substrates and used as anti-counterfeiting labels, corporate or exhibition logos, and laboratory instruction demos. This micro-assembly method is easy-to-use and applicable for objects made of different materials, suggesting utility for many microfabrication and micromanipulation applications in the future.
Trajectory prediction of moving targets on the sea surface is crucial for nautical safety, maritime traffic management and military applications. In recent years, with the development of deep ...learning techniques, the use of recurrent neural networks, especially LSTM (Long Short-Term Memory) networks, for analyzing and predicting temporal data has become increasingly popular. In this study, an improved LSTM model based on the attention mechanism is proposed for a more accurate prediction of the trajectory of a moving target on the sea surface. In traditional LSTM models, old information may be forgotten as time advances, leading to a decrease in prediction accuracy. To overcome this limitation, this paper integrates an attention mechanism that aims to strengthen the model's ability to capture important information in time series data. The attention mechanism enables the model to focus more on the part of the sequence that is most relevant to predicting the target trajectory by assigning different weights to different time steps. In this paper, the model is trained and tested using historical trajectory data of real sea surface moving targets. The experimental results show that compared to the standard LSTM model, our proposed improved LSTM model based on the attention mechanism significantly improves the prediction accuracy, showing better prediction accuracy and robustness.
Introducing common sense to natural language understanding systems has received increasing research attention. It remains a fundamental question on how to evaluate whether a system has a sense making ...capability. Existing benchmarks measures commonsense knowledge indirectly and without explanation. In this paper, we release a benchmark to directly test whether a system can differentiate natural language statements that make sense from those that do not make sense. In addition, a system is asked to identify the most crucial reason why a statement does not make sense. We evaluate models trained over large-scale language modeling tasks as well as human performance, showing that there are different challenges for system sense making.
The rising prosperity of today's society and the country's advancement in science, technology and social productivity have been accompanied by a higher level of material needs of the people and their ...increasing demand for cultural life. In today's life, all manner of enriched cultural activities have become common occurrences. Nevertheless, prominent security issues are arising from the booming performing arts industry. As commonly observed in cultural and artistic performances, spectators in the stands would often follow the rhythm of music or dance moves and are unable to suppress their emotions and rhythmical body movements, which will pose different dynamic loads on the stands and might even lead to the collapse of the stage. For the purpose of solving the above-mentioned issues, fiber grating is applied to measure the strain of the stands, and the influence of the movements following the music rhythm of the spectators on the stands is investigated in this paper.
The energy market is becoming more and more complex, and various harmonics and distributed energy have impacted the large power grid. Various factors have led to the need for more scientific and ...rational allocation of energy, so as to achieve continuous and reliable operation of the system. Realizing the control of energy storage systems to make them reliable and efficient has gradually become a huge challenge for modern power systems. Large-scale advanced battery energy storage technology faces the limitations caused by battery cell inconsistency, and the highly integrated and intelligent control of the equalization circuit is the solution to this problem. In this paper, by improving the structure of the traditional buck-boost circuit, a multi-input and multi-output converter which is easy to expand is proposed to realize the energy transfer between the individual cells of the battery pack. At the same time, the graph theory model of the equalization circuit is established. The efficiency of the related circuit is compared and analyzed through simulation and experiment. Finally, the superiority of the novel circuit topology proposed in this paper is verified. Simplify the practical problems of complex engineering into simple graphs in graph theory, so that comparisons under the same dimension can be easily obtained to obtain the merits and demerits of each method.
Due to the monomers difference caused during the production process, the inconsistencies of Lithium batteries in remaining capacity can affect the service life of battery packs and cause damage or ...even explosions. A new mod-ulnar equalization circuit, composed of improved DC-DC converters with the adaptive equalization control strategy based on ant coloy system (ACS), is proposed to enhance the performance of battery packs. The equalization circuit has the advantages of simplicity and easy implementation. It achieved the controllability of bidirectional energy equalization and current size. First, the circuit's structure and working principle are introduced. According to ACS, the simulation model of this balancing circuit with four batteries in series is built. The simulation results showed that equalization time is shortened by about 60% compared with the traditional control strategy. Then, a small-scale experimental circuit with 8 batteries was built to vertify the simulation results, and the batteries were balanced under charge, idle, and discharge states, respectively. The experiment results verified the correctness and feasibility of the method.
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