Here we present quantitative measurements of total electron numbers in laser-induced air breakdown at pressures ranging from atmospheric to 40 bar_g by 10 ns and 100 ps laser pulses. A quantifiable definition for the laser-induced breakdown threshold is identified by a sharp increase in the measurable total electron numbers via dielectric-calibrated coherent microwave scattering. For the 10 ns laser pulse, the threshold of laser-induced breakdown in atmospheric air is defined as the total electron number of ∼10⁶. This breakdown threshold decreases with an increase of pressure and laser photon energy (shorter wavelength), which is consistent with the theory of initial multiphoton ionization and subsequent avalanche processes. For the 100 ps laser pulse cases, a clear threshold is not present and only marginal pressure effects can be observed, which is due to the short pulse duration leading to stronger multiphoton ionization and minimal collisional avalanche ionization.

Recently, more and more researchers have focused on electrical textiles that can provide or convert energy to facilitate people’s lives. Knitting conductive yarns into ordinary fabrics is a common way for electrical textiles to transmit heat or electrical signals to humans. This paper is aimed at studying the resistance values and temperatures of electrothermal knitted conductive fabric (EKCF) subjected to certain voltages over time. Six types of EKCFs with structural differences were fabricated using a computerized flat knitting machine with intarsia technology. Uniform samples 10 × 10 cm in size were made from wool, as were two different specifications of silver-coated conductive yarns. The wool yarn and one silver-coated yarn were mixed to knit a resistance area 2 × 2 cm in size in the center of the EKCF to observe heating behaviors. The experiment results showed that when the EKCFs were subjected to certain voltages over time, the resistance values of the resistance area increased over a short time and then gradually decreased, and the temperature gradually increased in the first 1000 s and tended toward stability after a certain period of time. The structural coefficient $\mathsf{\kappa }$ between different knitted structures (which predicted the thermal properties of different EKCFs subjected to different voltages) was analyzed. These results are of great significance for predicting the electrothermal performance of EKCFs with different knitted structures. On the basis of these results, an optimized knitted structure was selected as the best EKCF for wearable textiles, and the findings contribute to the field of technological and intelligent electrothermal garments and related products.

With the rapid development of technical textiles, more and more researchers have focused on developing high performance textiles to meet various needs. The automotive industry is a major market for technical textiles. Compared to other types of fabric, weft-knitted fabric has good extensibility and elasticity, as well as a hand-feel, and it is gradually becoming the preferred type of interior fabric for automobiles. This paper aims to develop an automotive fabric with good comfort and durability. Sixteen types of weft-knitted fabrics with eight different structures and two different materials (draw textured polyester and textured polyamide yarn) were fabricated using a computerized flat knitting machine. Their durability and level of comfort were examined by measuring the tensile and tear strengths, abrasion resistance and air permeability. A fuzzy comprehensive evaluation method was employed to compare the comprehensive properties of the fabric. The results indicated that the overall performance of DTPA fabric was better than DTPE fabric, and an optimum structure was selected for an automotive interior. Meanwhile, we found that the air permeability of the fabric could be increased by using tuck stitches and that the strength and dimensional stability of fabric could be increased by adding tuck stitches and weft-insert yarns. The findings contribute to the field of technical textiles and provide ideas for the development of high-performance textiles.

In recent decades, sports and medical products, such as compression underwear and stockings, have been increasingly receiving more attention as more and more urbanites are beginning to focus on their health issues. In terms of compression garments, inverse relaxation takes place with frequent wear. Pressure retention on leg, body shaping, and muscle movement control during activity are highly related to this phenomenon. Elastic knitted fabrics are widely used for sportswear clothing. They have good mechanical and dynamic properties, which include good elasticity, recovery, tensile strength, etc. These properties have been extensively and recently studied by different researchers. However, the inverse relaxation of elastic knitted fabric is not a topic of study in the literature. In response to the research gap, this study systematically investigates the inverse stress relaxation of elastic knitted sportswear. A theoretical model is applied and validated through a series of experiments. The factor that affects the process of inverse relaxation and the relationship between relaxation and inverse relaxation are analyzed both theoretically and experimentally. The mechanism behind the structural deformation of elastic knitted fabric can then be intuitively revealed. This study therefore provides a new perspective for improving sportswear performance through fabric stitch design and engineering.

Three-dimensionally conformal porous microstructured fabrics (3CPMFs) are a new kind of modified fabrics with three-dimensionally conformal porous microstructures of introduced materials recently developed for wearable technology. They can effectively introduce customized functional performance based on the choice of brick materials, while at the same time maintain the excellent inherent properties of textiles. In this paper, based on the introduction of polystyrene with low thermal conductivity at only 8 × 10⁻⁴ g cm⁻², we developed a kind of polyester fabric-based 3CPMF with enhanced thermal insulation, while maintaining its unique fabric texture, flexibility, moisture permeability, and light weight. It was demonstrated to be a good textile material for the fabrication of wearable electrothermal textile (ET) devices with enhanced thermal management. Compared to pristine fabric-based ET devices, this kind of 3CPMF-based ET devices can obtain higher temperatures under the same input power to provide thermal comfort for human beings, while saving more electric power to achieve the same thermal equilibrium temperature. We believe that, based on the choice of different functional materials and textiles, a wide range of 3CPMFs with customized functionalities and properties can be designed and developed for the realization of a brand-new class of truly wearable devices with desired functional performance and daily garment-like safety and comfort.