Renmin University of China

About: Renmin University of China is a education organization based out in Beijing, Beijing, China. It is known for research contribution in the topics: China & Population. The organization has 11325 authors who have published 15498 publications receiving 238419 citations. The organization is also known as: Renmin University & People's University of China.

Climate change impact on China food security in 2050

Abstract: Climate change is now affecting global agricul- ture and food production worldwide. Nonetheless the direct link between climate change and food security at the nation- al scale is poorly understood. Here we simulated the effect of climate change on food security in China using the CERES crop models and the IPCC SRES A2 and B2 sce- narios including CO2 fertilization effect. Models took into account population size, urbanization rate, cropland area, cropping intensity and technology development. Our results predict that food crop yield will increase +3-11 % under A2 scenario and +4 % under B2 scenario during 2030-2050, despite disparities among individual crops. As a conse- quence China will be able to achieve a production of 572 and 615 MT in 2030, then 635 and 646 MT in 2050 under A2 and B2 scenarios, respectively. In 2030 the food security index (FSI) will drop from +24 % in 2009 to −4.5 % and +10.2 % under A2 and B2 scenarios, respectively. In 2050, however, the FSI is predicted to increase to +7.1 % and +20.0 % under A2 and B2 scenarios, respectively, but this increase will be achieved only with the projected decrease of Chinese population. We conclude that 1) the proposed food security index is a simple yet powerful tool for food security analysis; (2) yield growth rate is a much better indicator of food security than yield per se; and (3) climate change only has a moderate positive effect on food security as compared to other factors such as cropland area, population growth, socio-economic pathway and technology development. Relevant policy options and research topics are suggested accordingly.

Multistep approach to microscopic models for frustrated quantum magnets: the case of the natural mineral azurite.

Abstract: The natural mineral azurite ${\mathrm{Cu}}_{3}({\mathrm{CO}}_{3}{)}_{2}(\mathrm{OH}{)}_{2}$ is a frustrated magnet displaying unusual and controversially discussed magnetic behavior. Motivated by the lack of a unified description for this system, we perform a theoretical study based on density functional theory as well as state-of-the-art numerical many-body calculations. We propose an effective generalized spin-$1/2$ diamond chain model which provides a consistent description of experiments: low-temperature magnetization, inelastic neutron scattering, nuclear magnetic resonance measurements, magnetic susceptibility as well as new specific heat measurements. With this study we demonstrate that the balanced combination of first principles with powerful many-body methods successfully describes the behavior of this frustrated material.

Raman fingerprint of two terahertz spin wave branches in a two-dimensional honeycomb Ising ferromagnet

Abstract: Two-dimensional (2D) magnetism has been long sought-after and only very recently realized in atomic crystals of magnetic van der Waals materials. So far, a comprehensive understanding of the magnetic excitations in such 2D magnets remains missing. Here we report polarized micro-Raman spectroscopy studies on a 2D honeycomb ferromagnet CrI3. We show the definitive evidence of two sets of zero-momentum spin waves at frequencies of 2.28 terahertz (THz) and 3.75 THz, respectively, that are three orders of magnitude higher than those of conventional ferromagnets. By tracking the thickness dependence of both spin waves, we reveal that both are surface spin waves with lifetimes an order of magnitude longer than their temporal periods. Our results of two branches of high-frequency, long-lived surface spin waves in 2D CrI3 demonstrate intriguing spin dynamics and intricate interplay with fluctuations in the 2D limit, thus opening up opportunities for ultrafast spintronics incorporating 2D magnets. Characteristics of spin waves in recently discovered two-dimensional (2D) Ising ferromagnets are still lacking. Here, Jin and Kim et al. report Raman resonance evidence of two sets of surface spin waves in the 2D honeycomb ferromagnet CrI3.

Ethical leadership and job performance in China: : The roles of workplace friendships and traditionality

Abstract: This study examined the relationships between ethical leadership, as perceived by subordinates, and task performance as well as organizational citizenship behaviour towards the organization ( OCBO) and towards individuals ( OCBI), while lending consideration to the moderating roles of subordinates' workplace friendships and traditionality in China. The results, which were based on two-phase data from a sample of 312 supervisor-subordinate dyads in a manufacturing firm, indicated that ethical leadership positively related to subordinates' OCBO and OCBI. Moreover, subordinates' workplace friendships strengthened the relationship between ethical leadership and task performance, whereas subordinates' traditionality strengthened the relationships between ethical leadership and task performance, OCBO, and OCBI. The theoretical and managerial implications of these results were discussed. Practitioner points Findings provide evidence that enhancing ethical leadership promotes subordinates' OCBO and OCBI., Encouraging employees to develop friendships can enhance the positive effects of ethical leadership on task performance., Encouraging employees to hold traditional values can enhance the positive effects of ethical leadership on task performance, OCBO, and OCBI

Universal thermodynamics of strongly interacting Fermi gases

Abstract: Strongly interacting Fermi gases are of great current interest. Not only are fermions the most common particles in the universe, but they are also thought to have a universal thermodynamic behaviour for strong interactions1, 2, 3. Recent experiments on ultracold Fermi gases provide an unprecedented opportunity to test universality in the laboratory4, 5, 6, 7, 8. In principle this allows—for example—the interior properties of hot, dense neutron stars to be investigated on earth. Here we carry out a detailed test of this prediction. We analyse results from three ultracold fermion experiments involving two completely distinct atomic species in different kinds of atomic-trap environment6, 7, 8. The data are compared with the predictions of a recent strong-interaction theory9, 10. Excellent agreement is obtained, with no adjustable parameters. By extrapolating to zero temperature, we show that the experimental measurements yield a many-body parameter -0.590.07, describing the universal energy of strongly interacting Fermi gases.