This study investigates the feasibility of obtaining high-temperature (2000–2200 °C) measurements using thermionic emission from a W–La₂O₃ cathode in a low-pressure argon glow discharge environment. Compared to a vacuum environment, the cathode emission characteristics and temperature variation patterns in a plasma environment exhibit significant differences. These differences arise primarily from the competitive interplay between the thermionic emission cooling (TEC) effect and the ion bombardment heating (IBH) effect. Among the discharge parameters (temperature, applied bias voltage, and background pressure), the applied bias voltage is the key factor influencing this competitive interplay. Consequently, the cathode surface temperature exhibits three distinct regions as a function of bias voltage: the TEC-dominated region (10–20 V), the transition region (20–40 V), where TEC and IBH are nearly in equilibrium, and the IBH-dominated region (40–60 V). The results indicate that by adjusting the discharge parameters to place thermionic emission in the transition region, the TEC and IBH effects can be mutually offset. Under these conditions, the cathode temperature can be unambiguously determined from the measured emission current using the modified Schottky equation. This approach simplifies the functional relationship between emission current and temperature (J–T), thereby enabling high-temperature measurements to be obtained.

To evaluate the protective capacity of stiffened plates with arc-shaped supports (SPASs) under underwater near-field non-contact explosion (UNFNCE), a series of experiments were designed and conducted to investigate the dynamic responses of SPASs under varied explosion loads and structural parameters. A rapid calculation method based on an equivalent velocity field approach was established to analyze the energy absorption characteristics of SPAS under UNFNCE. Combined with energy analysis using the fast simulation results, a semi-analytical method was developed for predicting the dynamic response of SPASs. The results exhibit good agreement between predictions from the proposed methods and experimental measurements; both the fast calculation and semi-analytical approaches produce errors within commonly accepted engineering tolerances. These two methods can act as efficient and reliable tools for rapid dynamic response assessment of SPAS under UNFNCE, offering practical support for the anti-explosion design of ship protective structures.