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To solve the problem that the walking jitter of quadruped robots leads to the degradation of clarity of visual imaging, a quadruped robot visual imaging jitter compensation algorithm based on the theory of walking jitter is proposed. The D-H coordinate transformation method is used to establish the coordinate system of each joint of the leg. The kinetic equations of the leg are derived from the relationship between the rotational velocity and the moment of the leg joint, and the kinetic equilibrium equations of the quadruped robot body are established based on the spatial moment equilibrium theorem; the spring-mass model of the leg of the quadruped robot is used to construct the kinetic equations of the leg jittering, and the kinetic equations of the body jittering are derived using the moment equilibrium condition of the body center of gravity position and under the effect of the leg and body jitter to obtain the visual imaging device jitter quantity; finally, the tremor quantity is combined with the jitter quantity and rotation matrix to derive the walking jitter mathematical model of the quadruped robot visual imager, and the jitter compensation algorithm of quadruped robot visual imager is verified. The experimental results show that compared with the traditional Wiener filter algorithm for jitter compensation and the BP neural network jitter compensation algorithm, this algorithm improves the visual imaging by 10.8% and 3.3% in the two evaluation indexes of peak signal-to-noise ratio and structural similarity, respectively, and the de-jittering effect is better. [ABSTRACT FROM AUTHOR]

The current oil recovery of the Lucaogou shale oil reservoir is predicted to be about 7.2%. It is crucial to explore improved oil recovery (IOR) technologies, and further experimental and field research needs to be conducted to study the complex mechanism. In this study, laboratory experiments were carried out to investigate the performance of one-step and multi-step depletion, CO2 huff-n-puff, and surfactant imbibition based on nuclear magnetic resonance (NMR). The sweep efficiencies were assessed via NMR imaging. In addition, hybrid methods of combining surfactant with CO2 huff-n-puff and the performance of injection sequence on oil recovery were investigated. The experimental results indicate that oil recoveries of depletion development at different initial pressures range from 4% to 11%. CO2 huff-n-puff has the highest oil recovery (30.45% and 40.70%), followed by surfactant imbibition (24.24% and 20.89%). Pore size distribution is an important factor. After three more cycles of surfactant imbibition and CO2 huff-n-puff, the oil recovery can be increased by 11.27% and 26.27%, respectively. Surfactant imbibition after CO2 huff-n-puff shows a viable method. Our study can provide guidance and theoretical support for shale oil development in the Lucaogou shale oil reservoir. [ABSTRACT FROM AUTHOR]

Skeletal muscle contributes significantly to human health, which is closely relevant to human locomotion, energy metabolism, immune regulation, and aging. Skeletal muscle holds the potential to recover its healthy condition via self‐repairing after minor damage. However, the capacity of sarcous self‐repair becomes incompetent following massive trauma or some myopathy, which raises a huge demand for skeletal muscle regeneration. Skeletal muscle engineering aims to rebuild muscle tissues in vitro to repair muscle injuries, develop pathological models, advance myopathy‐related research, and explore myopathy‐related medications. This review summarizes the advances in skeletal muscle engineering, including the cell resources that can be used in muscle regeneration, the recent progress of rebuilding methods for skeletal muscle engineering, as well as the biomedical applications of engineered skeletal muscle for tissue repair, drug testing, disease modeling, and soft robots. Finally, the challenges and future perspectives are discussed on improving skeletal muscle engineering by integrating multidisciplinary approaches, thus accelerating the technological innovation and translational application of this area. [ABSTRACT FROM AUTHOR]

In this study, nuclear magnetic resonance and computed tomography scanning were used to analyze the production law and displacement mechanism of Jimusaer continental shale oil during CO2 huff 'n' puff, and the optimal parameters were determined. The results indicated that CO2 huff 'n' puff mainly produces crude oil in pore throats with 0.1–1 μm radii, while crude oil in pore throats with radii below 0.1 μm cannot be produced. Multiple CO2 huff 'n' puff cycles can connect fluids in fractures with fluids in large–medium pore throats, eliminate fracture effects on the oil recovery factor, and achieve coefficient development of both fractured and unfractured shales. In the CO2 huff 'n' puff process, core pressure change could be divided into three stages of injection–holding–depletion, and the oil displacement mode was the piston type. The study of huff 'n' puff parameters revealed that huff 'n' puff cycles and injection pressure have a great influence on the CO2 huff 'n' puff efficiency, while the injection timing and soaking time imposed relatively small effects. For continental shale in the Jimusaer Sag, the optimal CO2 huff 'n' puff parameters are five cycles, 4‐MPa injection timing, 25‐MPa injection pressure, and 12‐h soaking time. [ABSTRACT FROM AUTHOR]