RESUMEN
Accurate detection technology of the microwave electric field is an important foundation to explore new materials, devices, and electromagnetic effects. In this paper, the design of a microwave electric field detection enhanced by a resonant cavity was proposed and experimentally verified. The simulation results show that the enhancement factor is 3.45 at the position of 3 mm from the square SRR). By combining the experimental system, the actual enhancement factor is 3.31(6), and the corresponding electric field detection sensitivity is increased from 1.02 V/m to 0.30 V/m. The proposed scheme provides certain technical support for the weak microwave electric field detection and the development of the integrated atomic microwave detection unit.
RESUMEN
Dissimilarities in metal laser welding lead to brittleness in welded joints due to differences in the thermophysical and chemical properties between dissimilar base materials. To overcome such brittleness, the addition of a preset coating onto the base materials as an interlayer is a method for attaining reliable welded joints. Nd:YAG laser butt welding of DP590 dual-phase steel and 304 stainless, both with a thickness of 1 mm, was performed with a preset nickel coating as an interlayer using an electroplating process. The relationship between the microstructure and the mechanical properties of the welded joints was researched, the microstructure and composition of the weldment were analyzed, and the microhardness, tensile strength and corrosion resistance were tested. The results showed that the preset nickel coating increased the content of Ni element in the welded joints, which is beneficial to the formation of lath martensite. The average hardness of the welded joints increased by 12%, and the tensile strength was higher than 370 MPa. The corrosion rate of the welded joints can be slowed down, and the corrosion resistance can be improved by increasing the nickel coating.
RESUMEN
Driving forces are the factors that lead to the observed changes in the quantity and quality of ecosystem services (ESs). The relationship between driving forces and ESs involves considerable scale-related information. Place-based ecological management requires this information to support local sustainable development. Despite the importance of scale in ES research, most studies have only examined the association between ESs and their drivers at a single level, and few studies have examined this relationship at various scales or analyzed spatial heterogeneity. The purpose of this paper is to explore the significance of the scale-dependent effects of drivers on ESs for localized ecological management. The biophysical values of ESs were calculated using several ecological simulation models. The effects of driving forces on ESs were explored using the geographically weighted regression (GWR) model. Variations in the effects of driving forces on ESs were examined at three scales: provincial, ecoregional, and subecoregional scales. Finally, canonical correlation analysis was used to identify the major environmental factors associated with these variations in each ecoregion. Our results show that (1) the distribution of soil conservation and water yield is highly heterogeneous; (2) four driving forces have significant positive and negative impacts on soil conservation and water yield, and their effects on the two services vary spatially (p < 0.05); (3) the impacts of drivers on ESs vary across different spatial scales, with a corresponding shift in the related environmental factors; and (4) in the study area, at the provincial scale, physical, topographical, and biophysical factors were key factors associated with the variations in the relationship between ESs and drivers, and at the ecoregional and subecoregional scales, physical, socioeconomic, topographical, and biophysical factors all contributed to these changes. Our results suggest that significant differences in topographical conditions (e.g., altitude, slope) can be incorporated for exploring the relationship between drivers and ESs and optimizing ecological management at the provincial scale, whereas significant differences in physical and socioeconomic conditions (e.g., urbanization levels, human activity, vegetation coverage) are more meaningful for localized ecological management at the ecoregional and subecological scales. These findings provide a basis for understanding the relationship between drivers and ESs at multiple scales as well as guidelines for improving localized ecological management and achieving sustainable development.