Search Results (144)

This paper investigates strain-, twist-, and electric-field-tuned optical absorption in bilayer MoS₂, emphasizing spin-orbit coupling (SOC). A continuum model reveals competing mechanisms: geometric perturbations (strain/twist) and Stark effects govern one-/two-photon absorption, with critical thresholds (~9% strain, ~2.13° twist) switching spin-independent to spin-polarized regimes. Strain gradients and twist enhance nonlinear responses through symmetry-breaking effects while electric fields dynamically modulate absorption via band alignment tuning. By linking parameter configurations to absorption characteristics, this work provides a framework for designing tunable spin-resolved optoelectronic devices and advancing light–matter control in 2D materials. Full article

Platelet-rich plasma (PRP) has become an increasingly valuable biologic approach for personalized regenerative medicine because of its potent anti-inflammatory/healing effects. It is thought to be an excellent source of growth factors that can promote tissue healing and lessen fibrosis. Although this treatment has demonstrated effectiveness in numerous disease areas, its impact on pulmonary fibrosis (PF) caused by silver nanoparticles (AgNPs) via its antiapoptotic effects remains to be explored. AgNPs were synthesized biologically by Bacillus megaterium ATCC 55000. AgNP characterization was carried out via UV–Vis spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) imaging to reveal monodispersed spheres with a mean diameter of 45.17 nm. A total of 48 male Wistar rats divided into six groups, with 8 rats per group, were used in the current study on the basis of sample size and power. The groups used were the PRP donor, control, AgNP, AgNP + PRP, AgNP + dexamethasone (Dexa) rat groups, and a recovery group. Body weights, hydroxyproline (HP) levels, and CASP3 and TWIST1 gene expression levels were assessed. H&E and Sirius Red staining were performed. Immunohistochemical studies for inducible nitric oxide synthase (iNOS) and cluster of differentiation 68 (CD68) with histomorphometry were conducted. A significant reduction in body weight (BWt) was noted in the AgNP group compared with the AgNP + PRP group (p < 0.001). HP, CASP3, and TWIST1 expression levels were significantly increased by AgNPs but decreased upon PRP (p < 0.001) treatment. Compared with those in the control group, the adverse effects of AgNPs included PF, lung alveolar collapse, thickening of the interalveolar septa, widespread lymphocytic infiltration, increased alveolar macrophage CD68 expression, and iNOS positivity in the cells lining the alveoli. This work revealed that PRP treatment markedly improved the histopathological and immunohistochemical findings observed in the AgNP group in a manner comparable to that of the Dexa. In conclusion, these results demonstrated the therapeutic potential of PRP in a PF rat model induced via AgNPs. This study revealed that PRP treatment significantly improved the histopathological and immunohistochemical alterations observed in the AgNP-induced group, with effects comparable to those of the Dexa. In conclusion, these findings highlight the therapeutic potential of PRP in a rat model of AgNP-induced PF. Full article

The temperature-dependent polarization performance of super-twisted nematic liquid crystals (STN-LCs) when used as polarizers has garnered considerable scholarly attention. In this study, the transmittance of an STN-LC cell was measured under incident light wavelengths of 650 nm, 532 nm, and 405 nm over the temperature range of 30 °C to 100 °C. The STN-LC cell was employed both as the sample under test and as an analyzer in a rotational measurement setup to investigate how its polarization properties vary with temperature. The results indicate that the LC cell exhibits the characteristics of a linear polarizer under red light (650 nm) and violet laser (405 nm) across the full temperature range. However, under green laser (532 nm), when the temperature exceeds 60 °C, its extinction ratio is poor, suggesting its unsuitability for polarization applications under such conditions. A birefringence inversion formula was derived using the transmittance difference method, which effectively eliminates the influence of the glass substrates on the measured transmittance of the LC layer. Utilizing this method, a simple optical setup consisting of a polarizer and photodetector was constructed to accurately extract the birefringence of the LC. The birefringence of super-twisted nematic liquid crystal can be obtained by the transmittance difference method, which is low-cost, has a simple optical path, and is convenient for temperature-controlled experimental measurements of the liquid crystal cell. The findings of this study provide methodological support for the precise determination of birefringence in LCs exhibiting linear polarization characteristics. Full article

This study presents an optimized design and vision-guided control strategy for a multi-functional robotic gripper integrated into an automatic loading system for warehouse environments. The system adopts a modular architecture, including standardized platforms, transport containers, four collaborative 6-DOF robotic arms, and a multi-sensor vision module. Methodologically, we first developed three gripper prototypes, selecting the optimal design (30° angle between the gripper and container side) through workspace and interference analysis. A deep vision-based recognition system, enhanced by an improved YOLOv5 algorithm and multi-feature fusion, was employed for real-time object detection and pose estimation. Kinematic modeling and seventh-order polynomial trajectory planning ensured smooth and precise robotic arm movements. Key results from simulations and experiments demonstrated a 95.72% success rate in twist lock operations, with a positioning accuracy of 1.2 mm. The system achieved a control cycle of 35 ms, ensuring efficiency compared with non-vision-based methods. Practical implications include enabling fully autonomous container handling in logistics, reducing labor costs, and enhancing operational safety. Limitations include dependency on fixed camera setups and sensitivity to extreme lighting conditions. Full article

This study aims to develop a process to calculate the carbon footprint of a company in the textile sector for the automotive industry, thus addressing a research gap identified in this sector. Based on a structured calculation model, the project aspires to innovate by quantifying not only the greenhouse gas emissions at different stages of the company’s operations, including those generated by the consumed electricity and gas, but also the emissions related to external and in-house transportation and solid waste management. The approach includes the design of a specific calculator, capable of integrating variables such as energy consumption, transport and types of waste, analysing them in the light of recognised conversion factors. This tool not only allows for a detailed assessment of emissions but also supports strategic decision-making, guiding the implementation of more sustainable business practices. The results indicate that, considering the use of renewable energy sources, the company’s total emissions amount to approximately 18 thousand tonnes of carbon dioxide equivalent. On the other hand, considering non-renewable energy, purchased electricity accounts for 31 thousand megawatt-hours per year, corresponding to 5 thousand tonnes of carbon dioxide equivalent, with the twisting area being the largest consumer at 89% of total usage, followed by the dipping area. In terms of mobile combustion, raw materials contribute 1373 million tonnes of carbon dioxide equivalent, while finished products generate 1869 million tonnes of carbon dioxide equivalent. Among the most impactful variables, solid waste, and stationary combustion stand out as the main contributors. These findings highlight the need for concrete measures to mitigate climate change, such as transitioning from stationary natural gas combustion to green electric power; identifying companies with more suitable waste treatment solutions, process changes that reduce disposable, and easily substitutable materials; making use of green electricity; exploring alternative transport methods or combining different modes, such as using electric vehicles for short distances; and optimizing transport routes. These initiatives reinforce the company’s commitment to sustainable development goals and the promotion of responsible environmental practices. Full article

Plant tendrils exhibit intriguing tropism motions like bending, twisting, and coiling. Herein, we report the application of a liquid crystal elastomer (LCE) to make a light-sensitive and biomimetic coil to replicate behaviors of plant tendrils. The LCE coil consists of diacrylate azobenzene, diacrylate mesogens, and thiol-based spacers. These components are first mixed to form a highly viscous prepolymer solution through a thiol-acrylate Michael addition reaction. Subsequently, an extrusion–rolling process is developed to draw the viscous solution into a coil, which is mechanically stretched in a single direction to align mesogens in the LCE. Finally, the coil is photopolymerized under UV light to form an LCE coil with a diameter of 375 µm. The LCE coil possesses good rigidity and flexibility and shows movement upon light exposure. For example, the LCE coil shows a reversible bending up to 120° to 365 nm UV and 30% contraction to 455 nm visible light, respectively, due to trans-cis photoisomerization of azobenzene derivatives. When the coil is irradiated with UV light with an intensity up to 10 mW cm⁻², it can twist and coil up. It can also wrap around the UV light tube in 6 s, similar to a plant tendril. This type of light-responsive coil has great potential in making biomimetic plants or soft robotics. Full article

A novel sliding mode control (SMC) strategy incorporating an adaptive super-twisting algorithm is developed for permanent magnet synchronous motors (PMSMs), effectively mitigating high-frequency chattering while enhancing external disturbance rejection capabilities. Initially, a sliding surface is crafted based on the dynamic characteristics of the PMSM and real-time feedback. The super-twisting algorithm is subsequently applied adaptively to dynamically adjust the control effort required to maintain the sliding mode state, thereby ensuring precise and prompt intervention to uphold system stability and enhance response speed. Additionally, in light of operational challenges such as road-induced load disturbances, a Lyapunov-based disturbance observer is proposed for precise load torque estimation in PMSM systems. The efficacy of the proposed control and observation methods is substantiated through a hardware-in-the-loop experiment test, demonstrating that the developed sliding mode controller, leveraging the adaptive super-twisting algorithm, exhibits superior tracking and disturbance rejection capabilities, reduces steady-state current error, and bolsters system parameter robustness, and the modified extended state observer (MESO) exhibits commendable estimation performance. Full article

Sustainability has increasingly emphasized the importance of recycling and repairing materials. Cutting tools, such as milling cutters and drills, play a crucial role due to the high demands placed on products used in CNC machining. As a result, the repair and regrinding of these tools have become more essential. The geometric differences among machining tools determine their specific applications: twist drills have spiral flutes and pointed cutting edges designed for drilling, while end mills feature multiple sharp edges around the shank, making them suitable for milling. Taps and form cutters exhibit unique geometries and cutting-edge shapes, enabling the creation of complex profiles. However, measuring and classifying these tools for repair or regrinding is challenging due to their optical properties and coatings. This research investigates how lighting conditions affect the classification of tools for regrinding, addressing the shortage of skilled workers and the increasing need for automation. This paper compares different training strategies on two unique tool-specific datasets, each containing 36 distinct tools recorded under two lighting conditions—direct diffuse ring lighting and normal daylight. Furthermore, Grad-CAM heatmap analysis provides new insights into relevant classification features. Full article

We theoretically investigate the comprehensive modulation effect of interlayer twisting and external electric field to the two-photon absorption (TPA) in twisted graphene/hexagonal boron nitride (tG/hBN) heterojunction with small twist angles (2° < θ < 10°) starting from an effective continuum model. It is found that the TPA of tG/hBN is extended to the visible light band from infrared light band of that in twisted bilayer graphene (tBLG) due to the increase in energy band gap caused by twisting and the potential energy of the boron nitride atomic layer. And the TPA coefficient is enhanced several times via an external electric field, which increases the density of states, leading to an increase transition probability for two-photon absorption. Full article

Structured light encompasses a vast variety of light fields. It has unique properties such as non-uniform transverse intensity and a polarization pattern across their beam cross-sections. In this contribution, we discuss the photoexcitation of a single ionic target system driven by different sets of structured light modes. Specifically, we provide a compilation of transition amplitudes for various structured light modes interacting with atomic systems based on the first-order perturbation theory. To illustrate this, we will choose an electric quadrupole transition ($4s{}_{\mathrm{}}{}^2{S}_{1/2}_{\mathrm{}}^{\mathrm{}}\to 3d{}_{\mathrm{}}{}^2{D}_{5/2}_{\mathrm{}}^{\mathrm{}}$) in the target Ca⁺ ion driven by a structured light field. For this particular interaction, we examine how the beam parameters affect the population of magnetic sub-levels in the atomic excited state. Full article

Arrayed ultraviolet (UV) LED light sources have been widely applied in various semiconductor processes, ranging from photopolymerization to lithography. In practical cases, based on data provided by manufacturers, calibration of individual UV LEDs is often needed before their real usage in high-precision applications. In this paper, we present a high-precision, automated light source measurement platform, which can be applied to the performance evaluation of various types of light sources. In order to minimize errors introduced by the automated measurement system, the platform employs a sub-pixel measurement technique, along with a twist-angle method, to perform multiple measurements and analyses of the spatial intensity distribution of the light source on a given plane. Through noise analysis of repeated measurements, the platform’s effectiveness and reliability are validated within a certain tolerance range. The high-precision automated light source measurement platform demonstrates excellent performance in the precise control and data acquisition of complex light sources. The light source dataset derived from the test results can provide guidance for the optimization of light sources in fields such as lighting, imaging, and lithography. Full article

Jute fibers are renewable, light, and strong, allowing them to be considered as attractive materials in composite manufacturing. In the present work, a simple and effective method for preparing continuous pre-preg tapes from short jute fiber bundles (without twist) is developed and its application in winding forming is evaluated. Linear low-density polyethylene film (LLDPE) with good flexibility and weather resistance was used as the thermoplastic matrix; jute fiber bundles were first spread parallel to each other on an LLDPE film and then rolled up to form a pre-roll. The pre-roll enclosing fiber bundles was hot-pressed in a designed mold to form a pre-preg tape, where the fiber bundles were more parallel to the tape than the fibers in twine. Although the untwisted structure exhibited a lower tensile strength for the fiber bundle, it could be processed into a continuous pre-preg with higher tensile strength than the jute twine-impregnated pre-preg. This is based on the good impregnation of the short fiber bundle and its unidirectional, uniform strengthening in the continuous pre-preg. The tensile strength and modulus of the fiber bundle-reinforced pre-preg increased by 16.70% and 257.14%, respectively, compared with jute twine-reinforced pre-preg (within the fiber proportion of 40.wt%). When applied to winding, the fiber bundle-reinforced pre-preg showed advantages of interlayer fusion, surface flatness, and ring stiffness. In contrast, the twisted continuous structure did not retain its advantage in pre-preg. The development of pre-preg tapes by discontinuous fibers might be a good way for utilizing natural fibers in the field of green engineering due to its diverse secondary processing. Full article

Road extraction in remote sensing images is crucial for urban planning, traffic navigation, and mapping. However, certain lighting conditions and compositional materials often cause roads to exhibit colors and textures similar to the background, leading to incomplete extraction. Additionally, the elongated and curved road morphology conflicts with the rectangular receptive field of traditional convolution. These challenges significantly affect the accuracy of road extraction in remote sensing images. To address these issues, we propose an end-to-end low-contrast road extraction network called LCMorph, which leverages both frequency cues and morphological perception. First, Frequency-Aware Modules (FAMs) are introduced in the encoder to extract frequency cues, effectively distinguishing low-contrast roads from the background. Subsequently, Morphological Perception Blocks (MPBlocks) are employed in the decoder to adaptively adjust the receptive field to the elongated and curved nature of roads. MPBlock relies on snake convolution, which mimics snakes’ twisting behavior for accurate road extraction. Experiments demonstrate that our method achieves state-of-the-art performance in terms of F1 score and IoU on the self-constructed low-contrast road dataset (LC-Roads), as well as the public DeepGlobe and Massachusetts Roads datasets. Full article

Dielectric elastomer actuators (DEAs) are increasingly recognized for their potential in robotic applications due to their ability to undergo significant deformation when subjected to an electric field. However, they are often limited by their low output power, which can make their integration into dynamic systems like hopping robots particularly challenging. This research optimizes the performance by introducing a cone DEA with a novel type of semi-diamond preload mechanism. This type of preload mechanism can meet the requirements of a negative-stiffness preload and a light weight. According to the experiments, the DEA can provide 3.62 mW power and its mass is only about 17.5 g. In order to drive hopping robots based on a cone DEA, this research introduces an energy accumulation mechanism coupled with a constant-torque cam for a hopping robot. The hopping robot weighs approximately 30.3 g and stands 10 cm tall in its upright position. Its energy accumulation mechanism involves a gear and cam transmission system, which is the key to store and release energy efficiently. The primary components of this mechanism include a torsion spring that stores mechanical energy when twisted, a constant-torque actuation cam that ensures the consistent application of torque during the energy storage phase, and a conical DEA that acts as an actuator. When the conical DEA is activated, it pushes a one-way clutch to the rocker, rotating the gear and cam mechanism and subsequently twisting the torsion spring to store energy. Upon release, the stored energy in the torsion spring is rapidly converted into kinetic energy, propelling the robot into the air. The experiments reveal that the designed DEA can drive the hopping robot by using the energy storage mechanism. Its hopping height is related to the pre-compression angle of the torsion spring. The DEA can drive the rigid hopping mechanism, and the maximum hopping height of the robot is up to 2.5 times its height. DEA hopping robots have obvious advantages, such as easy control, quietness and safety. Full article

Traditional low-order flux sliding mode observer (FSMO) and quadrature phase-locked loop (QPLL) structures generally encounter issues such as estimated signal chattering and inadequate dynamic performance. To overcome these challenges, this paper proposes an iterative fast super-twisting flux sliding mode observer (IFST-FSMO) and a tangent quadrature phase-locked loop (TQPLL) for sensorless control of surface-mounted permanent magnet synchronous motors (SPMSMs). Building on the traditional super-twisting algorithm (STA), the IFST-FSMO is proposed to accelerate convergence and enhance chattering suppression, which incorporates a linear term and utilizes the hyperbolic tangent function to replace the intrinsic sign function. Notably, the feedback matrix is redesigned to ensure the algorithm’s stability during speed reversal. Furthermore, an iterative calculation strategy is implemented under low-speed and light-load conditions, improving steady-state accuracy of estimated flux while avoiding increased computational burden at medium and high speeds. Regarding position estimation, a novel TQPLL with correction factor is proposed, utilizing the tangent function of the electrical angle error to achieve normalization and bandwidth adaptation. Ultimately, the proposed method is implemented on a motor test platform. Comparative experimental results demonstrate that the IFST-FSMO combined with TQPLL exhibits superior dynamic response and steady-state accuracy, while achieving efficient speed reversal. Full article