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To improve the axial compression mechanical properties of the EPS particle-EPS board composite insulation wallboard, added fiber web at different levels of it, got the best arrangement to improve the performance of axial compression through the test.

Magnetic separation is an emerging and promising technology in biological sample preparation. In this paper, a high-intensity and high-gradient magnetic separation system was developed to separate magnetic nanobeads from aqueous solution. This system mainly consisted of a magnetic separator, a micropump and an electronic timer. The magnetic separator was designed by placing two columns of permanent magnets in an aluminum holder. Two magnets in each column were laid out in repelling mode and a hole between the two columns was used to accommodate a 1.5 ml tube. Working with the electronic timer, the micropump was employed to remove waste solution at a certain rate after magnetic nanobeads captured onto the sides of the tube wall. The experiments for separation of magnetic nanobeads with diameters of 150 nm and 50 nm using the developed magnetic separation system were conducted to optimize the key parameters of the system including nanobeads concentration, separation time and flow rate. The separation efficiencies of magnetic nanobeads increased as the nanobeads concentration and the separation time increased, whereas decreased when the flow rate was increased. Experimental results proved that the proposed magnetic separation system was able to separate magnetic nanobeads (diameters of 150 nm and 50 nm) with separation efficiencies of 99% and 90% in 30 min and 150 min respectively.

Based on plane strain theory, the formula for calculating the tensile stress on the interface between the steel tube and concrete under the axial pressure was derived, and the stress distribution coefficient K was analyzed. Practical formula for calculating the interfacial tensile stress of CFST members under low stress condition was fitted. Using the fitted formula the interfacial stress calculation process can be greatly simplified, and the results have enough assurance. This formula can be easily applied to CFST members’ interfacial stress calculation.

Two 1:2 reduced-scale model tests with different types of shear connectors are conducted to study the mechanical properties of shear connectors for a composite beam un- der complex stress conditions. The strain of the shear connector and relative slipping on the steel-concrete interface of the rigid shear connector model and flexible shear connector model under the same boundary conditions is measured. Responses of two types of shear con- nectors under three different load cases are compared. The test results show that the ultimate bearing capacity of concrete is the key factor of relative slipping on the steel-concrete inter- face, and differences between rigid and flexible shear connectors are large.