Qinghai University

The accumulation of dust on solar panels severely affects the power generation efficiency of photovoltaic systems.It is necessary to understand the cleaning mechanism of brush filaments against solar panels for mech. cleaning.In this paper, the cleaning force was calculated in using the nylon brush as the actuator.Under three bending states of brush filaments, the mech. model was derived by analyzing the interaction force of filament and dust, which assumed that the dust particles are rigid balls and the brush filaments are flexible beams.The normal force of the dust particle against the filament is dependent on the deflection angle, the axial and radial displacement of the terminal filament, and the cleaning force also depends on them.The average relative error is 9.2676% of the normal force between the model and experiment in an acceptable value.The results indicate that the nylon brush filaments have the optimal cleaning effect for solar panels, which the length of the filament is 20 mm, the filament diameter is 0.3 mm, and the axial displacement is 13-15 mm.This research presented an alternative solution to design the new tool for improving the cleaning efficiency of dust particles.

Microwave-Induced Breakdown Spectroscopy (MIBS) uses a localized microwave antenna to generate plasma directly on the solid sample surface, making it an efficient and cost-effective method for identifying material elemental composition. Unlike typical microwave optical emission spectroscopy methods that require high gas flow rates or complicated setups, the antenna-based MIBS method eliminates the need for extensive sample preparation and environmental constraints. This study investigates the dynamic characteristics of microwave-induced plasma (MIP) through the evolution of emission intensity using both spectroscopic and image analysis techniques. The temporal studies of spectral signal were conducted on different material types, i.e., aluminum, iron, and ceramics, followed by a detailed investigation of the plasma evolution and the impacts of microwave power, pulse durations, and repetition rate, performed on an aluminum sample. The results demonstrate that microwaves emitted from an antenna generate plasma on the sample surface with high emission intensity. Temporal spectral evolution studies reveal that plasma emission and lifetime are sustained by the microwave pulse, with the highest signal intensities for atomic and ionic emission lines observed at the end of the microwave pulse, regardless of material type. For aluminum and iron, signal intensities disappear beyond 1000 μs, indicating rapid plasma decay. In contrast, ceramics exhibit a longer-lived plasma, with measurable emission persisting up to 1200 μs. For the aluminum sample, increasing MW power from 1000 W to 3000 W enhances signal intensity from 0.9 × 10⁴ a.u to 2.4 × 10⁴ a.u due to increase in plasma temperature from ∼7100 K to 7600 K and electron density from 2.2 × 10¹⁷ to 2.7 × 10¹⁷ while reducing measurement uncertainty by increasing the likelihood of plasma formation. Further investigation of pulse duration and repetition rate effects reveals that a longer pulse improves emission intensity by supplying more energy, whereas low repetition rates stabilize the signal by enabling plasma cooling. These findings suggest that antenna-based MIBS provides a sophisticated and cost-effective alternative to existing spectroscopic techniques, offering the added benefit of direct microwave plasma generation compared to other microwave optical emission and laser spectroscopic methods.

Gastric cancer (GC) has a high incidence and poor prognosis, often metastasizing to the liver. Gamma-glutamyl transferase (GGT) is a key indicator of liver damage, and its family members are associated with various cancers. However, their expression and prognostic significance in GC remain unclear. This study utilized R to analyze the expression and prognosis of GGT family members using RNA-seq and clinical data from the TCGA database, applying Lasso regression for key gene identification. We identified GGTLC2 as a significant gene related to GC prognosis. We examined the clinical relevance, methylation levels, and copy number variations of GGTLC2 using the MEXPRESS database and performed GSEA analysis to identify enriched pathways. Additionally, we explored the relationship between GGTLC2 and immune cell infiltration, as well as immune-related genes, and established GGTLC2 knockdown and overexpression cell lines. The results indicate that GGTLC2 is highly expressed in GC and is associated with DNA methylation, copy number variation, and liver metastasis. Functionally, GGTLC2 is primarily enriched in oxidative stress and immune-related pathways, affecting immune infiltration and the expression of inflammatory factors in the tumor microenvironment. In vivo and in vitro studies demonstrate that knocking down GGTLC2 inhibits GC proliferation, invasion, and migration while promoting apoptosis and ferroptosis. Conversely, overexpressing GGTLC2 significantly increases the number of metastatic tumors in the liver. Overall, GGTLC2 may influence the occurrence, development, and liver metastasis of GC by inhibiting ferroptosis, making it a promising novel biomarker for the diagnosis and treatment of GC and its metastasis.