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The development of three-dimensional (3D) gradient porous graphene (GPG) patterns, leveraging the remarkable properties and unique structure of graphene, has garnered considerable attention owing to their excellent electrochemical and electrothermal performances. Among the numerous graphene synthesis methods, laser-induced graphene (LIG) stands out as an eco-friendly and practical approach for creating patterned graphene structures on commercial films, with synthetic details varying depending on the application. Unlike conventional LIG with uniform geometric characteristics, we developed an innovative approach for circular line-scribed ultraviolet (UV)-LIG patterning; these approaches utilize a high overlapping factor and low power to achieve uneven graphitization. A comprehensive analysis of the 3D GPG was conducted via specific surface area measurements, contact angle analyses, sheet resistance measurements, X-ray photoelectron spectroscopy, and Raman spectroscopy. These 3D GPG structures exhibit large surface areas, low sheet resistance, and superior ion transport, thus improving heater and ion-selective electrode (ISE) performances. The fabricated 3D GPG heaters were successfully applied to antibacterial surfaces, and the ISEs were applied in a sweat sensor was demonstrated owing to the remarkable combination of high surface area, low electrical resistance, and unique 3D porous structure. [Display omitted] [ABSTRACT FROM AUTHOR]

A new type of flow controller for medical injection was developed and evaluated. The flow rate was controlled by simultaneously varying the friction length and depth of the micro-channel such that the relation between the flow rate and the length of the channel becomes more linear. The micro-channel was fabricated using ultra-precision machining technology. A seal made of butyl rubber was used to stop fluid leakage. The butyl rubber was coated with silicone oil to make the controller rotate smoothly. The flow controller was validated by comparing experimental data with theoretical predictions. Good agreement was found between theory and experiment. [Copyright &y& Elsevier]

To enhance the thermal efficiency of aero-engines, many works on numerical and experimental evaluation of cross corrugated heat exchangers for applications such as intercoolers and recuperators have been reported. However, numerical analyzes of unit cells or of corrugated flow passages in cross corrugated heat exchangers cannot be compared directly with experimental analyzes performed only at inlets and outlets. This paper presents results of the direct measurement of static pressure distribution in a corrugated flow passage: measurement was performed by embedding pressure tapping holes connected with microchannels into the corrugated plate, which had a thickness of 200 μm. Four corrugated plates were stacked and brazed to manufacture a real scale cross corrugated heat exchanger. The static pressure distribution was successfully measured inside the compact and complex heat exchanger. The friction factors for different Reynolds numbers were correlated for hydrodynamic performance evaluation. Finally, the friction factor was discussed with a consideration of the accuracy of the manufacturing of the cross corrugated heat exchanger. [ABSTRACT FROM AUTHOR]