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This paper explores the relationship between urbanization rate and death incidence by applying panel threshold regression model to the inland provinces of China. The empirical results highlight that there is a nonlinear single threshold effect between urbanization and population health indicators. In China's inland provinces, the negative impact of urbanization on death rate is reduced when per capita GDP exceeds the threshold, that is, the positive impact of urbanization on population health is significantly weakened. Similarly, this result can also be applied to the north provinces, while there is a no threshold effect in south. These asymmetric effects are strongly related to geographical location, historical background, economic development conditions, and health policies. Therefore, in the urbanization process, while promoting the steady development of population urbanization, the government should also increase health investment to improve the system and mechanism, formulate policies to raise health awareness, protect residents' health and reduce the waste of health resources.

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A series of small‐molecule‐based hole‐transporting materials (HTMs) featuring a 4H‐cyclopenta[2,1‐b : 3,4‐b′]dithiophene as the central core with triphenylamine‐ and carbazole‐based side groups was synthesized and evaluated for perovskite solar cells. The correlations of the chemical structure of the HTMs on the photovoltaic performance were explored through different combinations of the central π‐bridge moieties. The optical and electrochemical properties, energy levels, and hole mobility were systematically investigated, revealing the significant influence of the central core planarity and packing structure on their photovoltaic performance. The optimized device based on CT1 exhibited a PCE (power conversion efficiency) of 17.71 % with a device architecture of FTO/TiO2 compact layer/TiO2 mesoporous/CH3NH3PbI3/HTM/MoO3/Ag, which was found to be on par with that of a cell fabricated based on state‐of‐the‐art spiro‐OMeTAD (16.97 %) as HTM. Moreover, stability assessment showed an improved stability for CPDT‐based HTMs in comparison with spiro‐OMeTAD over 1300 h.

In this paper, the nuclear magnetic resonance (NMR) measurements are carried out to evaluate the micro‐cracking characteristics of sandstones during the creep stage under the different levels of creep stresses. The variations in the parameters, including transverse relaxation time (T2) spectra distribution, percentage of the pore distribution, incremental value of porosity and ultrasonic P wave velocity are analysed. The results show that, during the creep stage, small pores in the rocks gradually evolve into large pores, resulting in an increase in damage of rocks. With the increase of the loading ratio, the increasing rate of porosity increases sharply, implying that the damage degree becomes more serious under the high loading ratio. When the loading ratio is larger than 0.7, the increasing rate of porosity and the decreasing rate of the P wave velocity both increases rapidly. During the creep stage, the relationship between micro‐crack and macro‐creep characteristics of rocks is established based on the analysis of the deformation and the porosity evolution during creep. It is found that, as the loading ratio increases, the increasing rate of porosity is linear with the creep strain. The NMR method offers a feasible option to identify micro‐cracking process of rocks during the creep stage, which can directly reflect the damage mechanism of rock caused by creep. The porosity of rocks is an effective parameter to evaluate the damage of rocks. The damage evolution of the specimen is highly anisotropic and is heavily related to the loading ratio during the creep stage. The relationship between the damage parameter and the loading ratio is exponential.