During the excavation of deep coal and rock mass, the radial stress of the free face changes from three-dimensional compression state to two-dimensional stress, bearing the combined action of dynamic disturbance and static load at the same time. With that, many mines suffer from dynamic disasters, such as coal and gas outburst, rock burst and rock caving during deep mining excavation, which is often accompanied by plate crack, spalling and other disasters, seriously affecting the stability of stope and roadway. Taking thin rectangular coal and rock mass as the research object, the dual equation of the free vibration was derived and the exact solution model of the free vibration was established with the use of Hamilton dual system. Based on the action characteristics of the uniform impact load, the effective mode of the forced vibration was obtained by using the Duhamel integral principle and the orthogonality of the mode function. Based on the third strength theory and the numerical simulation results, the dynamic damage process and development trend of coal and rock mass were analyzed under uniform impact load. It was concluded that the starting position of dynamic damage can be judged by the first order main mode, and the development direction and trend of the damage can be judged by the fifth and sixth order main modes. It was concluded that the vibration mode functions of coal and rock mass with four side fixed

The layered rock mass widely exists in mining, construction, transportation, and water conservancy projects, and the damage phenomena of plate crack and spalling often occurs in the process of coal and rock dynamic disaster in deep mining. Therefore, the rock mass nearby excavation surface is usually considered to be composed of layers of thin plate rock mass to reveal the damage and failure mechanism of rock mass. In the whole dynamic process of mining and coal and rock dynamic disaster, rock mass would bear the dynamic disturbance from mine earthquake, and at present, the mechanical characteristics of rock mass are mainly studied under static load, while dynamic mechanical response characteristics and the mechanisms of dynamic damage, failure, and disaster-causing are still unclear. This study mainly focused on the dynamic response characteristic and failure mechanism of rock mass based on a rectangular thin plate model. The frequency equations and deflection equations of the thin plate rock mass with different boundary conditions (S-F-S-F, S-C-S-C, and C-C-C-C) were established under free vibration by the thin plate model and the dual equation of the Hamilton system, and the deflection equations under impact load were derived based on the Duhamel integral. And then, the effective vibration modes of the thin plate rock mass with different boundary conditions and their natural frequencies were obtained by Newton’s iterative method. Based on the third-strength theory and the numerical simulation results by LS-DYNA, the maximum shear of the effective vibration modes and the processes of damage and failure under impact load were analyzed. The research results showed that the initial position of damage and failure may be determined by effective vibration mode with the lowest frequency; the develop tendency of which by the combined actions of other effective vibration modes and the effective vibration modes with lower frequency could have greater influence on the process of damage and failure of the thin plate rock mass, which are beneficial to revealing the mechanism of coal and rock dynamic disaster.

Today's global economy faces the most devastating challenges of global warming occasioned by overdependence on natural resources. Besides, the dilemma of choosing between economic benefits and environmental costs emanating from natural resources heightens the empirical relevance of green energy in recent times. To solve this developmental puzzle, the current study presents extends the knowledge frontier by evaluating the impacts of natural resource dependence, green energy (captured by biofuels and renewable energy), carbon tax, and technological innovation on environmental sustainability in G7 economies. The empirical model endogenizes environmental policy stringency and financial development from 1996 to 2019. The empirical verification anchors on second‐generation estimators entailing Cross‐Sectional Autoregressive Distributed Lag (CS‐ARDL), Common Correlated Effects Mean Group (CCEMG), augmented mean group (AMG), and novel Method of Moment Quantile Regression (MMQR). The fallouts from the analyses uncover that natural resource dependence militates against the attainment of the sustainability blueprint by escalating the surge in CO2 emissions in G7 countries. Similarly, the feedbacks from financial development support the surge in emissions. On the flip side, green energy, technological innovation, carbon tax, and environmental policy appear as effective tools for mitigating the surge. The Fully Modified Ordinary Least Square (FMOLS) estimator for the country‐specific analysis corroborates the panel findings. Additionally, two channels of causalities, including unidirectional and bidirectional nexuses, are apparent from the estimated model. Policy measures are suggested based on empirical findings.

The Civil Code has not yet articulated fully what the “separation of the three property rights” with respect to residential plot rights should mean. This is due to the inadequate development of the theoretical basis of the reform of residential property rights in the Civil Code. Future stipulation on residential plot rights in the Civil Code should aim to define both the eligibility requirements and rights, and the use rights for residential plots. Both of those are derivative of collective ownership rights. For use rights, the new definitions should apply: use rights with respect to residential plots should become transferrable and complete. The new eligibility rights should be clarified as a membership right, a major component of the rights of being a member of the collective. It should include the right of usage and the right to benefits therefrom, while excluding the rights to request distribution of or transfer of the land.

Based on the dual equation of Hamilton system and Duhamel's integral, and the orthogonality of the deflection equations, the mechanical model of homogeneous rectangular thin plate rock mass was established. And the results showed that the effective vibration modes of thin plate granite with four sides fixed were the 1st, 5th and 6th orders under uniform dynamic load, and their vibration frequencies were 310rad/s, 975rad/s and 1309rad/s respectively. Under sustained dynamic load, moreover, the change of the vibration state of the 1st mode was the most sharp, and the positive and negative alternation of its amplitude was the most frequent in the whole period, which had the most obvious effect on the vibration of the thin plate rock mass. Based on the Fourier transform formula, the Fourier series expressions and waveforms of sustained dynamic loads which contained rectangular wave, triangular wave and impact wave were obtained. The vibration characteristics of thin plate rock mass under these three kinds of sustained dynamic loads, the dynamic distribution of deflection, stress and maximum shear stress, as well as the dynamic damage and failure modes were all obtained. The results showed that plate cracks occurred firstly in the middle of the four sides and these cracks would propagate rapidly along the boundary of the thin plate rock mass; and then, plate cracks occurred at the central of the thin plate and the main develop tendency of these cracks was outward along the long central axis, moreover, these cracks also tended to expand outward along the short side central axis. It could be concluded that the initial failure position of the thin plate rock mass could be determined by the 1st effective mode, and the development direction and trend of the damage could be determined by 5th and 6th effective vibration modes; under sustained dynamic load, tensile-shear failure occurred at four sides and shear failure at four corners; The tensile failure occurred in the central area of the thin plate, which developed into a main crack along the central long axis and a secondary crack along the short central axis, forming an " O-十" fracture pattern.