Si@TiN composites show excellent electrochemical properties and suppressed volume expansion compared with pure silicon nanoparticles (Si NPs).
To compare the epidemiological and psychological features of globus symptoms between individuals from urban and rural areas in Guangzhou.In total, 3360 individuals aged 18 years and over were selected to participate in our questionnaire investigation using random cluster sampling under the stratification of a urban area and a rural area. The questionnaire comprised questions on personal characteristics and globus symptomatology and psychological characteristic and sleep quality scales.Lifetime prevalence and Glasgow-Edinburgh throat scale scores of globus symptoms were greater in the urban area than in the rural area, but no significant differences in sex ratio or onset age between individuals with globus were found. The incidences and severity of anxiety, depression, and sleep disorders were significantly higher among patients who presented with globus in the urban area than among those in the rural area.The lifetime prevalence of globus symptoms and the psychological features of globus patients differ between urban and rural inhabitants. We should pay more attention to these differences.
In view of the anti-friction and anti-adhesion characteristics of bionic surface structure in bioengineering, a new processing technology of hole-to-hole strip sprinkler tool is proposed innovatively to achieve precision and large-scale surface micro-texture manufacturing. On the basis of electrolytic jet mask processing, the array structure of strip nozzle with variable hole spacing was designed. Combining with electric field parameters, the model was established by COMSOL Multiphysics software and the simulation analysis was carried out. Experiments show that the technology has high processing efficiency, low surface roughness, regular morphology and good consistency of the fabricated arrays, which provides a new idea for the fabrication of bionic micro-texture arrays.
High nickel ternary cathode materials are less expensive, more productive, and less environmentally harmful than conventional cathode materials. Thus, it becomes one of the best cathode materials for lithium-ion batteries. However, there are also clear drawbacks to high nickel ternary materials, for instance its inadequate cycle life, poor structural and heat stability, which limit its future development. In this work, LiNi0.8Co0.1Mn0.1O2 (NCM811) material was studied and modified using Li3BO3, a lithium-ion conductor-type compound, as its coating layer. Studies reveal that after 1 wt percent -Li3BO3 coating, the first discharge capacity at a 2 C rate rose from 162.7 mAh g-1 to 185.9 mAh g-1. After 250 cycles, the capacity retention of the Li3BO3-coated sample was 87%, compared to just 82.5% for the uncoated sample. The introducing of Li3BO3 coating material of NCM811 can significantly improve the electrochemical performance of materials for lithium-ion battery cathodes that are high in nickel ternary.
Metal borides have excellent chemical and electrochemical stability, high electrochemical sensitivity, and abundant active sites. According to experiments, metal borides can greatly reduce the shuttle effect in lithium-sulfur batteries and boost their electrochemical performance when used as sulfur host materials. In this thesis, we use polar lanthanum boride materials as materials for lithium-sulfur batteries that modify separators, and take advantage of its strong chemical bonding with polar polysulfides to reduce the shuttle effect. The experimental data demonstrate that the polar lanthanum boride can significantly improve the overall reaction kinetic performance as well as cyclic stability of the cell, resulting in excellent electrochemical performance.
Aiming at improving the response speed and robustness of wheeled mobile robots, this paper uses neural networks to identify the dynamic functions of mobile robots, and proposes an improved adaptive super-twisting sliding mode controller. First, this paper improves the sliding mode surface of super-twisting sliding mode control, which effectively speeds up the response speed of the system. Second, the robust adaptive law is utilized to eliminate the influence of uncertain parameters in super-twisting sliding mode control, which improves the robustness of the system and greatness reduces the chattering. In addition, the use of a high-gain observer to estimate the speed information of the mobile robot in real time avoids the shortcomings of direct measurement of speed information and realized the output feedback control of the system.
In order to enhance the control stability and anti-interference ability of quadcopter, this paper presents a quadcopter based on double-layer PID control, and designs a quadcopter with STM32 as the main controller, and simulates and verifies its control system attitude. Firstly, the nonlinear attitude mathematical model of the aircraft is established by the four-element method, and the relationship between the attitude angle and the angular velocity of the aircraft is obtained by solving, so that the measurement data of multi-attitude sensors of the four-axis aircraft can be better fused. Then, according to the deviation between the target attitude and the current attitude of the aircraft, a double-layer PID control method is proposed based on the traditional PID controller. The outer loop controls the angle of the aircraft and the inner loop controls its angular velocity to improve the adaptability and accuracy of the aircraft. At last, the attitude of quadcopter with two controllers is simulated and compared by Matlab simulation software. The simulation results show that the quadcopter with PID control has a slow response time, and the attitude stabilization time is 2.7s, while the quadcopter with double PID control has a fast response time, and the attitude stabilization time is 0.4 s, which has good control stability and strong anti-interference ability, and improves the adaptive ability and robustness of aircraft control.
Micron particle sorting has an important role in biomedicine, renewable energy, and micro-manufacturing. In this study, a fishbone-shaped micron particle sorting device was designed based on the dielectrophoretic manipulation of micron particles technique. Firstly, the simulation model of multi-physics field coupling is established using experimental data, and the results are calculated and analyzed using the method of finite element analysis. Finally, according to the simulation results, the factors affecting particle manipulation are particle dimensions, number of electrodes, voltage magnitude, and sheath flow rate. Studies have shown that when the sorting particle diameter is different, increasing the sheath flow speed, voltage strength, and the number of electrodes can improve the sorting effect. By modifying the factors affecting the dielectrophoretic manipulation of micron particle sorting, it can make the present design applicable to the sorting of different micron-size particles and provide a significant reference value for the subsequent particle sorting method.
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