A CHS-to-CFRHS Y-joint that consists of a circular hollow section (CHS) brace and a concrete-filled rectangular hollow section (CFRHS) chord by welding has a simple and smooth weld profile that saves time and cost for the fabrication of CHS-to-CFRHS Y-joints and leads to a superior fatigue performance, compared with other welded tubular joints. This investigation presented an analysis of the stress concentration factors (SCFs) of CHS-to-CFRHS Y-joints subjected to axial tension loading of the brace. First, a finite element (FE) modelling method, which was validated with the experimental results cited in the reference, was utilised to establish the FE models of CHS-to-CFRHS Y-joints. Then, a parametric analysis was conducted to investigate the influences of the significant non-dimensional geometric parameters on the SCFs of CHS-to-CFRHS Y-joints. It is found that the intersection angle of the brace and chord has an important influence on the magnitudes of the SCF values. An increase in the intersection angle of the brace and chord will increase the values of the SCFs at the 60° location and saddle. The values of the SCFs at the 60° location and saddle reach the maximum value when the intersection angle of the brace and chord reaches 90°. Furthermore, on the basis of the large database of the SCF results, empirical design equations were established to calculate the SCFs at the crown toe, 60° location and saddle via multiple regression analysis. A safety factor was applied to the empirical design equations to ensure safe and reliable results of SCF calculations for the fatigue design of CHS-to-CFRHS Y-joints in a composite truss structure. Ultimately, a comparative analysis of SCFs was conducted with the FE models of welded tubular joints with rectangular hollow section (RHS) chords and CFRHS chords. The results reveal that infilling concrete in the chord leads to a reduction in SCFs along the weld profile of more than 11% on average, and the peak SCF decreases by more than 15%.

In modern radiation sensor systems, the analog output of charge-sensitive preamplifiers (CSA) often suffers from long exponential tails, which severely limit the performance of the sensor system at high counting rates. At high counting rates in nuclear spectroscopy, overlapping exponential pulse tails from charge-sensitive preamplifiers lead to baseline drift and degraded energy resolution. Effective pole–zero cancellation (PZC) is necessary to mitigate these effects; however, conventional PZC tuning is typically manual and repetitive. We present an FPGA-based automatic digital PZC algorithm for nuclear pulse spectroscopy systems that estimates the preamplifier decay time constant online and automatically adjusts the PZC filter in real time. The proposed system combines high-speed digital pulse acquisition with FPGA firmware to achieve robust baseline restoration, pulse deconvolution, and improved energy resolution. Experimental validation with a high-purity germanium (HPGe) detector and a ⁶⁰Co gamma source demonstrates that the automatic PZC achieves near-optimal tail cancellation and recovers accurate pulse amplitudes. Compared to manual tuning, the adaptive approach yields superior baseline stability and approximately 6.8% better energy resolution for the 1332.5 keV peak, while reducing adjustment time from minutes to seconds.