M. Lei | Searcharxiv

arXiv2025

3D Surface Reconstruction and Volume Approximation via the meshless methods

In this paper, we propose several mathematical models for 3D surface reconstruction and volume estimation from a set of scattered cloud data. Three meshless methods including the interpolation-based method by RBF, PDE-based approach by Kansa's method and the Method of Fundamental Solutions are employed and compared. For the optimal recovery of the surfaces, the selection of free parameters in related PDE models are further studied and analyzed. Besides, several criteria like distance are employed in above methods instead of the classical parameter lambda determination strategy, which leads to a more reliable reconstruction performance. Finally, the volume estimation of 3D irregular objects is proposed based on the optimal reconstructed geometric models via proposed meshless methods. Numerous numerical examples are presented to demonstrate the effectiveness of the proposed surface reconstruction methods and the volume estimation strategy.

math.NA↗

arXiv2018

Study of radon reduction in gases for rare event search experiments

The noble elements, argon and xenon, are frequently employed as the target and event detector for weakly interacting particles such as neutrinos and Dark Matter. For such rare processes, background radiation must be carefully minimized. Radon provides one of the most significant contaminants since it is an inevitable product of trace amounts of natural uranium. To design a purification system for reducing such contamination, the adsorption characteristics of radon in nitrogen, argon, and xenon carrier gases on various types of charcoals with different adsorbing properties and intrinsic radioactive purities have been studied in the temperature range of 190-295 K at flow rates of 0.5 and 2 standard liters per minute. Essential performance parameters for the various charcoals include the average breakthrough times ($τ$), dynamic adsorption coefficients (k$_a$) and the number of theoretical stages (n). It is shown that the k$_a$-values for radon in nitrogen, argon, and xenon increase as the temperature of the charcoal traps decreases, and that they are significantly larger in nitrogen and argon than in xenon gas due to adsorption saturation effects. It is found that, unlike in xenon, the dynamic adsorption coefficients for radon in nitrogen and argon strictly obey the Arrhenius law. The experimental results strongly indicate that nitric acid etched Saratech is the best candidate among all used charcoal brands. It allows reducing total radon concentration in the LZ liquid Xe detector to meet the ultimate goal in the search for Dark Matter.

physics.ins-det↗