Institute of Fundamental Technological Research

Transparent electrodes are vital for optoelectronic devices, but their development has been constrained by the limitations of existing materials such as indium tin oxide (ITO) and newer alternatives. All face issues of robustness, flexibility,conductivity, and stability in harsh environments. Addressing this challenge, we developed a flexible, low-cost titanium nitride (TiN) nanomesh transparent electrode showcasing exceptional acid−alkali resistance. The TiN nanomesh electrode, created by depositing a TiN coating on a naturally cracked gel film substrate via a sputtering method, maintains a stable electrical performance through thousands of bending cycles. It exhibits outstanding chemical stability, resisting strong acid and alkali corrosion, which is a key hurdle for current electrodes when in contact with acidic/alkaline materials and solvents during device fabrication. This, coupled with superior light transmission and conductivity (88% at 550 nm with a sheet resistance of ∼200 Ω/sq), challenges the reliance on conventional materials. Our TiN nanomesh electrode,successfully applied in electric heaters and electrically controlled thermochromic devices, offers broad potential beyond harsh environment applications. It enables alternative possibilities for the design and fabrication of future optoelectronics for advancements in this pivotal field.

transparent electrode, titanium nitride, flexible, corrosion resistant, mesh, smart window

Plasma-treated polystyrene particles (PSP) are key building blocks in the fabrication of two- dimensional nanostructure arrays. Oxygen plasma etching can shrink PS particles and is a widespread tool in fundamental research and applications, but its effect has not been well understood. Here, we show that oxygen plasma induces an ultra-thin cross-linking layer on the surface of the PSPs, which increases their solvent resistance. We found in X-ray photoelectron spectroscopy (XPS) fine structure and valence band probing that the polymer C–C bonds are breaking and ecombining to form oxygenated functional groups. Our results explain, why oxygen plasma etched PS particles are more difficult to dissolve in nanofabrication procedures. Further, we used the ultra-thin crosslinked polymer layer to construct novel substrate-base microcavity arrays.

Polystyrene particle, Oxygen plasma, Cross-linking

The hydrostatic bearing is the core component of ultra-precision computer numerical control (CNC) machine tools. Because the temperature rise in the oil film of hydrostatic bearings seriously affects the working accuracy of the bearings, it is important to study the flow and heat transfer characteristics of the oil film. Based on the physical model of an incompressible viscous fluid flowing in a flat microfluidic boundary layer, velocity, temperature and heat flux distribution equations of oil film are constructed by theories of heat transfer and hydrodynamics. Then, the effects of several parameters on velocity distribution, temperature distribution and heat flux distribution are analyzed, such as the upper plate velocity, the channel length, and so on. The results show that the dimensionless velocity of the oil film decreases with the increase in the upper plate velocity and the channel length. The oil film temperature distribution can be divided into three zones: the increasing zone, stabilizing zone and decreasing zone. The heat flux decreases linearly with the increase in the plate thickness, and increases linearly with the increase in the temperature difference.

microfluidic boundary layer,hydrostatic oil film,velocity,temperature,heat flux

Damage of bridge cables is mainly manifested as the decrease in cable forces. These forces are affected by the boundary conditions, cable length, cable stiffness, and cable appendages, making it hard to identify the cable forces. Based on the substructure isolation method, this study proposes an approach for cable force identification to judge cable damage by adding virtual supports to each cable so that the cables share the same length and boundary conditions. The cable forces can then be identified according to the relationship between the natural frequency and cable forces. The basic concept is that the boundary sensors are transformed into virtual supports by a linear combination of the convolution of measured responses to achieve the zero boundary response. A finite element model of a suspension bridge was used to validate the proposed method in a simulation. When the virtual supports were added to the cables, the relationship between the cable forces and the natural frequency was almost linear, and the cable damage could be successfully identified with 5% noise. Finally, the effectiveness of the proposed method was verified experimentally, and the natural frequency of the isolated cable substructure was confirmed to be a highly sensitive damage indicator.

cable damage, cable forces, natural frequency, structural health monitoring (SHM), substructure isolation method, virtual supports