History dynamics of unified empire in China(770 BC to 476 BC)

The laws and regulations in human history can be revealed by computational models.From 221 before Christ(BC)to 1912 Anno Domini(AD),the unification pattern has dominated the main part of Chinese history for 2132 years.Before the emergence of the first unified empire,the Qin Empire in 221 BC,there existed the Eastern Zhou dynasty(770 BC to 221 BC).This long dynasty has two stages,and here we focus on the first stage.This Spring-Autumn stage was from 770 BC(with 148 states)to 476 BC(with 32 states).The whole country(China)is modelled as a multi‐agent system,which contains multiple local states.They behave autonomously under certain action rules(wars and conflicts),which forms the main reason for the annexations and disappearance of most states.Key factors(power,loyalty,bellicosity and alliance)have been considered in our model settings,and simulation outcomes will be monitored and collected.Eventually,an optimal solution is obtained,which well unveils the internal mechanism and statistical features of real big history.Furthermore,counterfactuals are used to explore the non‐linear effects of the key factors,which deepens the authors’understanding of civilisa-tion evolutions in human history.

A real-time sensing system based on triboelectric nanogenerator for dynamic response of bridges

The strain of bridges under traffic loads is time-varying and of small amplitude(~10^(-6)),which is a type of cumulative response and needs long-term continuous monitoring.To precisely capture the time-varying responses,a dynamic strain triboelectric nanogenerator(TENG)sensor with superior response capability,sensitivity,self-powered,and long-term stability is proposed in this paper.An analytical correlation between the structural strain response signal and the detected electrical signal is established for long-term continuous quantitative strain measurements based on the principles of contact electrification and electrostatic induction.A series of experiments are conducted to investigate the output performance of the proposed lateral-sliding mode TENG sensors.The results reveal that,with the loading condition with frequencies lower than 10 Hz,the time-varying strain responses of the steel bridge within the range of 3 to 150 microstrains can also be detected with high precision of 0.1 microstrains.And it achieves long-term stability after 10000 loading cycles compared with commercial sensors.The proposed novel sensing theory and method based on TENG technology can be applied as a new alternative approach for monitoring realtime structural strain information quantitatively with general applicability and feasibility for bridges.