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KM2A is one of the main sub-arrays of LHAASO, working on gamma ray astronomy and cosmic ray physics at energies above 10 TeV. Detector simulation is the important foundation for estimating detector performance and data analysis. It is a big challenge to simulate the KM2A detector in the framework of Geant4 due to the need to track numerous photons from a large number of detector units (>6000) with large altitude difference (30 m) and huge coverage (1.3 km2). In this paper, the design of the KM2A simulation code G4KM2A based on Geant4 is introduced. The process of G4KM2A is optimized mainly in memory consumption to avoid memory overflow. Some simplifications are used to significantly speed up the execution of G4KM2A. The running time is reduced by at least 30 times compared to full detector simulation. The particle distributions and the core/angle resolution comparison between simulation and experimental data of the full KM2A array are also presented, which show good agreement.

Metal-coated polymer particles are used as a critical component in anisotropic conductive adhesives. The mechanical properties of polymer particles are of crucial importance to both application and design. In this study, a nanoindentation-based flat punch test approach has been developed to determine the mechanical properties of two polymer particles. Particle A failed at an average deformation of 67.2 %, while no failure was observed for particle C when a maximum 10 mN normal load was applied. The contact stress – strain behavior and contact modulus were obtained from the flat punch test.

The effect of hydride and hydrogen-induced martensite on the fracture toughness of a TiNi shape memory alloy has been investigated using a notched tensile specimen. The results show that the fracture toughness of the hydrogenated samples decreases linearly with increasing hydrogen concentration, and the relative fracture toughness loss is as high as 96%. The relative fracture toughness loss induced by the martensite, however, is about 1.8%, and is independent of hydrogen concentration. The decrease in the fracture toughness of hydrogenated samples is almost completely due to the hydride. The relative fracture toughness loss induced by the hydride, ΔK_IC^TiNiH/K_IC, increases with increasing hydride content, W_TiNiH, i.e., ΔK_IC^TiNiH/K_IC(%) = 93[1−exp(−W_TiNiH/9.5)]. Microcracks can generate along the hydrides during charging at

The mechanical properties and fracture mechanism of irradiated and unirradiated boron containing Type 304 stainless steel are studied. Four different batches with different boron weight percentages are used. One of these batches was manufactured by a conventional wrought technique, while the others were manufactured by a powder metallurgy technique. The irradiated specimens were subjected to a fluence level of 5 × 1019or 1 × 1021n/m2. The mechanical and fracture tests were performed at temperatures of 233, 298, and 533 K. No significant effects on the mechanical properties or fracture behavior were observed as a result of neutron irradiation and/or temperature. The ductility and toughness of the borated steel were found to decrease with increasing boron content. The effect of boride on void nucleation and linkage was found to play an important role in the fracture behavior of borated steel.

The effect of extract of Hirudo Medicinalis L. on preventing the adhesion of calcium oxalate crystals to 0.1 M hydrochloric acid-injured bladder urothelium of the rat was studied. It was found that in this species the extract coated to the bladder mucosa after it was instilled into the chemically injured bladder; and the adhesion of calcium oxalate crystals was prevented. In regard to the anti-adhesion property the Hirudo extract appears more effective than heparin, a documented glycosaminoglycan.

(1-x)BaZr0.2Ti0.8O3-xBa0.7Ca0.3TiO3(BZT-xBCT) system is a lead-free piezoelectric material with excellent piezoelectric response. But the temperature instability has seriously restricted the application of this system. In this work, the influence of precursor and synthesizing method on the piezoelectric temperature stability has been studied. And the results show that the piezoelectric temperature stability could be substantially improved by using suitable precursor and synthesizing method. The BZT-0.5BCT ceramic synthesized by using three-step synthesizing method has a huge piezoelectric constant (d33= 668 pC/N) and meanwhile has a good temperature stability. The SEM and XRD analysis show that the excellent piezoelectric properties are related to ceramic grain size and phase structure. Moreover, our result provides a simple and efficient method to improve the piezoelectric properties of the BZT-0.5BCT system and could accelerate application process of the ceramics.