Chen Yang

The foundation of the national economy is agriculture, agricultural modernization is the symbol of national modernization and agricultural mechanization is an important symbol of agricultural modernization. In this paper, the authors conducted an analysis of the agricultural mechanization levels of 31 provincial areas in China. In order to assess the agricultural mechanization levels of the provincial areas in China as accurately as possible, the authors adopted indicators in the year 2005, the year 2010 and the year 2015, and used the comparative static analysis method to observe the dynamic changes in the data over the three years. Eight items, including total agricultural mechanization power/grain output (10 million watts/10 k tons), number of large and medium-sized tractors/grain output (pcs/10 k tons), tractor plowing area/grain output (k hectares/10 k tons), total input of agricultural mechanization business operation/grain output (million yuan/10 k tons), total income of agricultural mechanization business operation/grain output (million yuan/10 k tons), and fuel consumption for agricultural production/grain output (hundred tons/10 k tons), were used as assessment indicators. With the gray weighted cluster assessment instrument, 31 provincial areas of China were classified into five gray categories at high development level, relatively high development level, medium development level, medium to low development level and low development level. An objective, scientific and comprehensive assessment of the cluster results was conducted in an effort to better provide references for the authorities to draft relevant policies and measures.

Nuclear fuel performance is deteriorated due to radiation defects. Therefore, to investigate the effect of irradiation-induced defects on nuclear fuel properties is essential. In this work, the influence of radiation defects on the thermo-mechanical properties of UO₂ within 600–1500 K has been studied using the molecular dynamics method. Two types of point defects have been investigated in the present work: Frenkel pairs and antisites with concentrations of 0 to 5%. The results indicate that these point defects reduce the thermal expansion coefficient (α) at all studied temperatures. The elastic modulus at finite temperatures decreases linearly with the increase in concentration of Frenkel defects and antisites. The extent of reduction (R) in elastic modulus due to two different defects follows the trend R_f > R_a for all studied defect concentrations. All these results indicate that Frenkel pairs and antisite defects could degrade the performance of UO₂ and should be seriously considered for estimation of radiation damage in nuclear fuels used in nuclear reactors.