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For forty years, there has been a widely held belief that over 2,000 years ago the Chinese Qin developed an advanced chromate conversion coating technology (CCC) to prevent metal corrosion. This belief was based on the detection of chromium traces on the surface of bronze weapons buried with the Chinese Terracotta Army, and the same weapons’ very good preservation. We analysed weapons, lacquer and soils from the site, and conducted experimental replications of CCC and accelerated ageing. Our results show that surface chromium presence is correlated with artefact typology and uncorrelated with bronze preservation. Furthermore we show that the lacquer used to cover warriors and certain parts of weapons is rich in chromium, and we demonstrate that chromium on the metals is contamination from nearby lacquer after burial. The chromium anti-rust treatment theory should therefore be abandoned. The good metal preservation probably results from the moderately alkaline pH and very small particle size of the burial soil, in addition to bronze composition.

Municipal household waste (MHW) separation is a fundamental way to achieve waste reduction and a recycling economy. This study takes the positions of government and residents in MHW separation as the research object, and aims to explore the change process and influencing factors of their decision-making behavior, which is of great significance to attract residents to participate in MHW separation and establish an effective MHW separation mechanism to solve MHW pollution. This paper firstly establishes an evolutionary game model between government and residents in MHW separation; secondly, the payoff matrix of the system is determined, and the replication dynamic equations under different constraints are calculated to obtain the evolutionary stability strategy of the system, and the stability conditions are analyzed; Finally, through numerical simulation, the decision-making behavior of MHW separation and its influencing factors are studied, and the rationality of the model is verified. The results show that: (1) In the process of MHW separation, residents often choose not to separate without government regulation; (2) Environmental fee rates and government effort have great impacts on residents’ decision-making behavior; (3) The increase of penalty intensity can significantly drive residents to separate MHW; (4) The sensitivity of residents’ behavior decision to subsidy coefficient is the lowest among all the variables, and the incentive effect of increasing subsidy coefficient is not obvious. The research results can not only provide theoretical guidance for policy makers to develop waste management policies, but also provide valuable insights for local communities to guide residents’ MHW separation behavior.

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