Crosslinking density of vulcanized rubber which was filled with carbon black and silica was experimentally researched, and its corresponding heat generation, dynamic lag loss (tanδ) and loss modulus ( E″) were also studied. Based on these tests, the model of the relationship among them was established. The results showed that the characteristic value of crosslinking density Vr almost showed downward trend as a straight line when the quantity of silica increased, but temperature rise, loss modulus E″ and tanδ increased obviously. Silane coupling agent Si-69 could improve the crosslink density and dynamic performance. In the drawing, linear correlation was good in linear fitting between temperature rise and loss modulus, as well as between temperature rise and tanδ. Keywords: vulcanized rubber; crosslingking density; heat generation; hysteresis

Distortional buckling is one of the important buckling models of steel-concrete composite beam in negative moment region. Rotation restraining rigidity and lateral restraining rigidity which steel beam web to bottom plate of steel-concrete composite are the key factors to influence the distortional buckling behavior. A comprehensive and intensive study on rotation restraining rigidity and lateral restraining rigidity which steel beam web to bottom plate of I-shaped steel-concrete composite beam in negative moment region is conducted in this paper. Energy variation principle is adopted to deduce the analytical expressions to calculate the rotation restraining rigidity and lateral restraining rigidity. Combined with the buckling theory of axial compression thin-walled bars in elastic medium, the buckling moment is obtained. Theoretical analysis shows that the rotation restraining rigidity and lateral restraining rigidity of steel beam web appear to have a linear relationship with the external loads and could also be negative. Compared with other methods, the results calculated by the proposed expressions agree well with the numerical results by ANSYS. The proposed expressions are more concise and suitable than the existing formulas for the engineering application.

This do In this paper, based on the Wilkinson power divider, a modified Wilkinson power divider using a microstrip in isolation is discussed. It can reduces the size of the circuit board area. What’s more, the isolation bandwidth can be extend by the Wilkinson power divider using a microstrip in isolation. Firstly, this paper illustrates the principles of the traditional Wilkinson power divider. By introducing the concept of isolation network, the real and imaginary part of the traditional Wilkinson power divider are derived. And then, the principle diagram the Wilkinson power divider with RLC isolation network are shown, we also give the expression of the real part and imaginary part of the isolation network. Lastly, we introduce the modified Wilkinson power divider using a microstrip in isolation, and give the expressions of real part and imaginary part of the isolation network, and the above three kinds of real part and imaginary part of Wilkinson power divider are simulated. Through simulation, we found the power divider using a microstrip in isolation has better physical performance.