Abstract Nowadays, fire accident is happening frequently which brings serious damages to people’s lives and properties; at present, fire-fighting robot is unable to perform targeted fire-fighting and combustion source at high places has brought difficulties to fire control and fighting; therefore, fire-fighting and assistance are facing unprecedented challenges. In view of this, the paper researched and developed an automatic control system for elevating fire-fighting robot, so as to solve the key difficulties and problems for fire control and fighting of fire-fighting robots. The research target consists of three aspects, firstly, the system has realized the elevating fire control and fighting function; secondly, we have designed an automatic control system for elevating fire-fighting robot based on ROS structure; thirdly, the paper has established the automatic control strategy play for raise arm of the elevating fire-fighting robot featured with stable and controllable operation, so as to solve the problem of unsteadiness in the elevating process and speed up application and popularization of fire-fighting and disaster rescue of the fire-fighting robot.
Abstract Liquid metal (LM) has potential applications in flexible electronics due to its high electrical conductivity and high flexibility. However, common methods of printing LM circuits on soft substrates lack controllability, precision, and the ability to repair a damaged circuit. In this paper, we propose a method that uses a magnetic field to guide a magnetic LM (MLM) droplet to print and repair a flexible LM circuit on a femtosecond (fs) laser-patterned silicone surface. After mixing magnetic iron (Fe) particles into LM, the movement of the resultant MLM droplet could be controlled by a magnetic field. A patterned structure composed of the untreated flat domain and the LM-repellent rough microstructure produced by fs laser ablation was prepared on the silicone substrate. As an MLM droplet was guided onto the designed pattern, a soft LM circuit with smooth, uniform, and high-precision LM lines was obtained. Interestingly, the MLM droplet could also be guided to repair the circuit broken LM lines, and the repaired circuit maintained its original electrical properties. A flexible tensile sensor was prepared based on the printed LM circuit, which detected the bending degree of a finger.
Abstract Fog generation can severely damage optical systems by degrading the light absorption rate and imaging quality of optical components. Furthermore, fog can reduce the light flux and transmittance of the optical system, resulting in poor imaging clarity and contrast. Studies have focused on minimizing fog formation and effects. Drawbacks such as high energy consumption and waste pollution severely limit the application of conventional methods. However, achieving high fog resistance of optical components remains a challenge. A novel method of fabricating anti‐fogging slippery surfaces (inspired by the anti‐fog mechanism of the mammalian cornea) on silica glass by using femtosecond lasers is proposed to achieve durable and environment‐friendly optical devices that can achieve anti‐fogging in real time. The femtosecond laser wet etching method is used to fabricate the inside cabin of glass. The cabin filled with graphene spontaneously heats the sample under sunlight to prevent fog formation. In addition to exhibiting excellent anti‐fogging characteristics, the prepared sample achieves high optical transmittance, high durability, and excellent self‐repair capability. Thus, the proposed method exhibits considerable potential for application in numerous domains.
We present a fabrication method for 3D microtransformers with air core inside silica glass by means of femtosecond-laser-wet-etching (FLWE) and metal-microsolidifying, for very high frequency applications. A fabricated transformer with 24turns of primary coil and 12 turns of secondary coil,yielded an inductance of 70nH and 55nH. The maximum transformer efficiency of 62% was measured at a load of 50 Ω. Finally, the embedded 3D micro-transformer can be easily integrated with other microelectrical, mechanical and optical systems, applying in MEMS, sensors and lab-on-chips.
The dynamic model of semiconductor fiber ring laser (SFRL) is improved by employing the distributed birefringence model of the fiber. A matrix is introduced to the laser model which is made up of a stochastic sequence with Rayleigh distribution. The framing structure characteristic of chaos waveform and the similarity of adjacent frames are observed with this improved model. It is the fiber birefringence that contributes to the framing structure of output chaos waveforms and the adjacent-frame similarity. The disturbance changed the birefringence Rayleigh distributed and then changed the Jones matrix of the fiber ring. Namely, the initial state of the chaotic system is changed. Duo to the sensitivity of a chaotic system to its initial conditions, the change brings variety in the output waveform. Therefore the adjacent-frame similarity decreases when a disturbance acts on the fiber. The disturbance in different position leads to different decrement in the degree of similarity of adjacent frames. So the validity of the cross-correlation method for detecting and locating a disturbance is confirmed by the simulation again.
Controlling the underwater bubble wettability on a solid surface is of great research significance. In this letter, a simple method to achieve reversible switch between underwater superaerophilicity and underwater superaerophobicity on a superhydrophobic nanowire-haired mesh by alternately vacuumizing treatment in water and drying in air is reported. Such reversible switch endows the as-prepared mesh with many functional applications in controlling bubble’s behavior on a solid substrate. The underwater superaerophilic mesh is able to absorb/capture bubbles in water, while the superaerophobic mesh has great anti-bubble ability. The reversible switch between underwater superaerophilicity and superaerophobicity can selectively allow bubbles to go through the resultant mesh; that is, bubbles can pass through the underwater superaerophilic mesh while are fully intercepted by the underwater superaerophobic mesh in a water medium. We believe these meshes will have important applications in removing or capturing underwater bubbles/gas.
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