Intraocular pressure (IOP) is a crucial physiological indicator for the diagnosis and treatment of glaucoma. The current infrequent IOP measurement during an office visit is insufficient to characterize the symptoms. Here, an LC resonator strain sensor in a contact lens, composed of a stretchable inductance coil using liquid metal and a chip capacitor, was developed for real-time IOP monitoring. The lens sensor was operated on the basis of ‘mechanical-electrical’ principle. The rising IOP will increase the curvature radius of the cornea and stretch the inductance coils through the cornea and tear film, leading to a decrease in resonant frequency. The theoretical model of the whole process has been established and explored. The sensor has been scientifically designed and fabricated to be ultra-soft, comfortable, safe without leakage and has a stable signal. The sensor was calibrated on two silicone rubber model eyeballs, respectively, showing linear and stable responses. An experiment on porcine eyes in vitro was conducted. The sensor can track IOP changes and shows much higher sensitivity than the current mainstream lens sensors, which is even an order of magnitude higher than the existing inductive sensor. The high-sensitivity and ultra-flexible liquid-metal-based lens sensor is a promising approach for 24 h continuous IOP monitoring in clinics.

In this paper, we present the development of microfluidic contact lenses, which is based on the advantages of wearable microfluidics and can have great potential in the ophthalmology healthcare field. The development consists of two parts; the manufacturing process and the usability tests of the devices. In the manufacturing process, we firstly extended silane coupling and surface modification to irreversibly bond plastic membranes with microchannel-molded silicone rubber, to form the plastic-PDMS plane assemblies, and then molded the plane into a contact lens by thermoforming. We systematically investigated the effects of thermoforming factors, heating temperatures and the terrace die’s sphere radius on channels by using the factorial experiment design. In addition, various tests were conducted to verify the usability of the devices. Through blockage and leakage tests, the devices were proved to be feasible, with no channel-blockages and could stand high pressures. Through a wearing test, the contact lenses were confirmed to be harmless on the living body. Furthermore, by performing the manipulating test, the device was proved to be liquid-controllable. These works provide a foundation for the applications of microfluidic contact lenses in ophthalmology.

Structured light technology is typical for capturing 3D point cloud data. This paper proposes a 3D reconstruction system to obtain point cloud data of complex objects based on nine-order Gray code and an eight-step structured light projection combined with a phase shift and phase unwrapping method. In this system, two projectors serve as bilateral projectors for structured light, along with a camera and rotating platforms. These components were used to obtain point cloud data from multiple perspectives, which helps avoid the shadow areas caused by a single projection angle and provides complementary point cloud data. The point clusters scanned under each perspective were transformed into the same coordinate system. Furthermore, a distance-based point cloud noise removal algorithm was proposed to optimize platform noise and facilitate point cloud data fusion. The experimental results proved that the system effectively captures 3D point cloud data for complex objects. The dimensional quantitative analysis of an aero engine blade was also performed.

Coalfield fires represent a critical environmental and safety concern, warranting a comprehensive understanding of the factors influencing the reactivity of oxidized coal residues within fire zones. This study investigates the influence of the oxygen volume fraction and oxidation temperature on the residual structure of oxidized coal, elucidating the underlying mechanisms driving reduced coal reactivity. The representative oxidation conditions for coalfield fire zones were determined. Through industrial and elemental analyses, complemented by methods such as infrared diffuse reflection, specific surface area determination, and pore size analysis, results indicate that higher temperatures and oxygen levels decrease volatile matter and fixed carbon, notably above 400 °C due to oxygen-deficient combustion. Hydroxyl groups decrease with a rising temperature in high oxygen conditions, while carboxyl groups increase at lower temperatures with elevated oxygen. Oxygen-lean and high-temperature conditions reinforce the coal structure, evidenced by the reduced condensation index in aromatic hydrocarbon. Oxidation alters the pore morphology, progressing from micropores to larger irregular pores through various stages, including pore formation, expansion, and merging. Elevated oxygen levels intensify oxidation, consuming the coal carbon matrix and reducing micropores, hindering internal gas diffusion, which is the key to a reduced coal reactivity in fire zones.