Changes of China’s Status in the Global System and Its Influencing Factors:A Multiple Contact Networks Perspective

Clarifying China’s position in the global system is an important logical basis for developing national diplomacy.Although much research has been done on China’s development status,most studies have been based on country comparisons or institutional en-vironment.In today’s networked era in which the global economy,trade,personnel,and information are closely connected,studies on China’s global position and its status changes and influencing factors in multiple contact networks are still insufficient.In this study,from the perspective of diverse global contact networks,we constructed economic,cultural,and political influence indices to explore the changes and influencing factors on China’s status in the global system from 2005 to 2018.The results show that during the study period,China’s global influence in the fields of economic ties,cultural exchanges,and political contacts increased significantly,but its influ-ence in the fields of cultural exchanges and political contacts lagged far economic ties.The pattern of China’s economic influence on various economies around the world has shown a transformation from an‘upright pyramid’to an‘inverted pyramid’structure.The proportion of these economies in low-influence zones has decreased from more than 60%in 2005 to less than 20%in 2018.China’s cultural and political influence on various economies around the world has increased significantly;however,for the former,the percentage of high-influence areas is still less than 20%,whereas for the latter the percentage of these economies in medium-and high-influence areas is still less than 50%.Analyses such as a scatter plot matrix show that geographical proximity,economic globalization,close cooperation with developing countries,and a proactive and peaceful foreign policy are important factors in improving China’s status in the diverse global network system.

Discrete element simulation of effects of multicontact loading on single particle crushing

Particle crushing commonly occurs in granular materials and affects their structures and mechanical properties.Unlike idealized particles in experimental single particle crushing tests with two loading points,natural particles are crushed under multicontact loading.To date,the criteria and patterns of par-ticle crushing under multicontact conditions are not fully understood.By using the three-dimensional discrete element method,this report explores the effect of multicontact loading on the crushing criterion of a single particle,the crushing pattern,and the relationship between the particle crushing strength and loading distribution.The particles are modelled as aggregates of glued Voronoi polyhedra.The numer-ical results indicate that the logarithm of the mean principal stress has a good linear correlation with the coordination number.For a specific coordination number,the number of child particles presents a significant normal distribution.For a specific number of child particles,the volumes of child particles can be statistically described as normal or gamma distribution.Three typical models are proposed to qual-itatively analyse the relationship between the loading distribution and crushing strength.The relevant conclusions can be helpful in engineering practice and in further studies on crushable granular materials via the discrete element method.