Key approaches to water environment need to be discussed for ecological protection and quality development of Yellow River stream. Prospect theory is used to establish a triple government-enterprise-private evolutionary gaming model on the consideration of irrational decision maker; numerical simulation is applied to analyze its evolution process. Enterprises eventually trend to strictly discharge pollution and the public trend to not participate in the supervision; the simulated results are consistent with the actual in Yellow River stream under intensifying governmental harness. The public's selection is a little lagging to governments, suggesting a leading role of governments on the public in water environmental harness. While evaluating the impacts of fines, enterprises' green subsidy and public supervision on evolution results, no one is found obviously affecting the finally-reaching stable strategy time, meaning the original selection is a key. Suggestions presented based on the evolution results provide theoretical supports and decision references for ecological protection and quality development in Yellow River stream. Local governments shall enlarge inputs on pollution water facilities construction according to laws and regulations, and boost trans-stream cooperation via data platform. Enterprises shall clarify their social responsibilities and take extra consideration on heavily pollution projects, strictly abiding by the quota in pollution emission. Governments may increase the green subsidy to enterprises for pollution emissions within stream, driving them to green innovation and to use of clean energy. The public needs to take responsibility for protecting water environment in Yellow River stream, supervising pollution discharges and reporting illegal activities when necessary. Governments shall set up stimulating means by clarifying the stimulating standard and applying diversified ways to encourage all involvements in protecting water environment in Yellow River stream.

To study the conductivity changing rules of low-rank coal reservoir during methane absorption and desorption, this paper, based on a case study on No.4 coal seam in Binchang coal mine, measures the resistivity of different coal samples during methane absorption and desorption, studies the conductivity changing rules and mechanism, and compares their variance of different coal rocks. Conductivity rises during the absorption process with an ascending pressure. Relation among resistivity, absorption quantity and equilibrium pressure can be described as a quadratic function. During pressure-descending-desorption process, conductivity rises slightly; it has linear relation with absorption quantity and equilibrium pressure. Heat-releasing and coal matrix swelling make a rise in conductivity during methane absorption, and vice versa. Methane absorption results in an irreversible change in coal structure; its resistivity cannot be recovered to its original level even after methane desorption. Durain, with high ash, even pore throat structure and less charged particles, is weaker than vitrain in conductivity, but stronger in absorption, leading to a greater and faster decrease in conductivity during methane absorption.