For survival and development, autonomous agents in complex adaptive systems involving the human society must compete against or collaborate with others for sharing limited resources or wealth, by using different methods. One method is to invest, in order to obtain payoffs with risk. It is a common belief that investments with a positive risk-return relationship (namely, high risk high return and vice versa) are dominant over those with a negative risk-return relationship (i.e., high risk low return and vice versa) in the human society; the belief has a notable impact on daily investing activities of investors. Here we investigate the risk-return relationship in a model complex adaptive system, in order to study the effect of both market efficiency and closeness that exist in the human society and play an important role in helping to establish traditional finance/economics theories. We conduct a series of computer-aided human experiments, and also perform agent-based simulations and theoretical analysis to confirm the experimental observations and reveal the underlying mechanism. We report that investments with a negative risk-return relationship have dominance over those with a positive risk-return relationship instead in such a complex adaptive systems. We formulate the dynamical process for the system's evolution, which helps to discover the different role of identical and heterogeneous preferences. This work might be valuable not only to complexity science, but also to finance and economics, to management and social science, and to physics.

In circuit breakers, high temperature arcing may lead to material erosion at the contacts. In this paper, numerical investigations have been performed in order to study the arc behaviours under the influence of copper vapours contamination in a simple Laval nozzle. The arc is assumed to be in local thermodynamic equilibrium. The erosion rate is estimated by considering the energy balance processes at the contact surface. Computations have been performed by a commercial computational fluids dynamics package (PHOENICS). The effects of contact polarity have also been investigated. It has been found that the presence of copper vapours cools down the arc temperature at the region close to the contacts. However, at current zero, the copper vapours concentration is very low. Post arc simulation has been performed in order to determine the critical rate of rise of recovery voltage (RRRV). Good agreement has been achieved with the experimental measurement of RRRV. It has been predicted that the contact erosion has a negligible effect on the interruption capability of the breaker.

Abstract. Lightning faults occupy in the majority of instantaneous fault and reclosing can usually be successful, so power supply can be restored without immediate patrol in many cases. Firstly, this paper introduces the lightning fault positioning and identifying method. Then test electrical performance of insulators after lightning strike from 110kV lines. Data shows that lightning strike has little effect on the electric performance of insulator. Finally, illustrating disposal process of the 110 kV transmission line after lightning fault, certifying that the power supply reliability be ensured without line patrol.

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