In this study, we analyzed the changes of houdy temperature in some regions of Guanzhong Plain in the north of Qingling Mountains on December 4, 2012. The results show that daily variation of temperature was abnormal ...In this study, we analyzed the changes of houdy temperature in some regions of Guanzhong Plain in the north of Qingling Mountains on December 4, 2012. The results show that daily variation of temperature was abnormal in some regions of Guanzhong Plain on December 4, 2012, and medium fog and haze inhibited the increase of air temperature in the urban area of Xi＇an in the morning of December 4, so that air temperature went up slowly during the day of December 4. The sinking of the northwest cold air before arriving Guanzhong Plain as well as atmospheric com- pression warming effect caused by Qinling terrain blocking were the main reasons for the abnormal increase of temperature in some areas of Guanzhong Plain. Compared with surrounding districts and counties, urban heat island effect was more obvious in the urban area of Xi＇an.展开更多
Significant anomalies were observed at the geomagnetic stations in the southwest region of China before the Yingjiang M_S6. 1 earthquake and the Ludian M_S6. 5 earthquake in 2014.We processed the geomagnetic vertical ...Significant anomalies were observed at the geomagnetic stations in the southwest region of China before the Yingjiang M_S6. 1 earthquake and the Ludian M_S6. 5 earthquake in 2014.We processed the geomagnetic vertical component diurnal variation data by the spatial correlation method. The results show that during the period from April 1 to May 20,2014,there existed quasi-synchronous decrease changes in the coefficient curves between the five geomagnetic stations of Guiyang,Hechi,Nanshan,Muli,Yongning and Xinyi and Hongshan stations. Furthermore,there was a high gradient zone in the normalized correlation coefficient contour map with background values removed. The epicenters of the Yingjiang M_S6. 1 earthquake and the Ludian M_S6. 5 earthquake are located in the gradient zone or near the gradient zone.展开更多
Much demanded and overused are the critical rare-earth elements such as Pr, Nd, Dy, and Tb with increasing need of Nd Fe B-type rare-earth permanent magnets in the enlarging application areas, developing new high-tech...Much demanded and overused are the critical rare-earth elements such as Pr, Nd, Dy, and Tb with increasing need of Nd Fe B-type rare-earth permanent magnets in the enlarging application areas, developing new high-tech industries, and emerging cutting-age frontiers. The balance and efficient use of rare-earth resources comes into being the national strategy, national defense, and border safety for many major countries and regions in the world.（Nd,Ce）Fe B-based permanent magnetic materials, which can not only reduce cost but also offer a feasible way for integrated and effective utilization of rare earth resources,have received much attention in recent years. The existence of CeFe2 and the mixed valence state of Ce in Ce Fe B compound, the different metallurgy behavior and the particular processing as well as potential various magnetic-hardening mechanisms, however, make it quite different from Nd-based alloys.For instance, the coercivity of Ce-containing magnets in some certain composition range, is even higher than that of the counterpart pure Nd-based magnets though the Ce-containing magnets possess inferior intrinsic properties. Consequently, it is very important to design proper composition and structure, optimize processing, and analyze the mechanisms in depth for this kind of magnet. High performance and cost-effective magnets can be fabricated if we can make full use of the composition＇s inhomogeneous and abnormal coercivity variation of the Ce-containing permanent magnets. In this paper, we have summarized the phase structures, magnetic properties and microstructures of（Nd,Ce）Fe B-based permanent magnetic materials to shed light on further research and development of this type of so-called ＂gap magnet＂.展开更多
基金Supported by the Special Project for Forecasters of Shaanxi Meteorological Bureau in 2013 (2013Y-17) Key Scientific Research Projectof Shaanxi Province (2013Z-3)
文摘In this study, we analyzed the changes of houdy temperature in some regions of Guanzhong Plain in the north of Qingling Mountains on December 4, 2012. The results show that daily variation of temperature was abnormal in some regions of Guanzhong Plain on December 4, 2012, and medium fog and haze inhibited the increase of air temperature in the urban area of Xi＇an in the morning of December 4, so that air temperature went up slowly during the day of December 4. The sinking of the northwest cold air before arriving Guanzhong Plain as well as atmospheric com- pression warming effect caused by Qinling terrain blocking were the main reasons for the abnormal increase of temperature in some areas of Guanzhong Plain. Compared with surrounding districts and counties, urban heat island effect was more obvious in the urban area of Xi＇an.
基金sponsored by the Spark Program for Earthquake Science and Technology,China Earthquake Administration(Serial No.XH17010Y)the Seismic Tracking and Orientation Task,China Earthquake Administration(Serial No.2018010401)Major Scientific and Technical Project of Science and Technology Department of Inner Mongolia in 2016(Strong Earthquake Track in the Short Stage and Integration Innovation of Stereoscopic Observation Technology in Space and Ground)
文摘Significant anomalies were observed at the geomagnetic stations in the southwest region of China before the Yingjiang M_S6. 1 earthquake and the Ludian M_S6. 5 earthquake in 2014.We processed the geomagnetic vertical component diurnal variation data by the spatial correlation method. The results show that during the period from April 1 to May 20,2014,there existed quasi-synchronous decrease changes in the coefficient curves between the five geomagnetic stations of Guiyang,Hechi,Nanshan,Muli,Yongning and Xinyi and Hongshan stations. Furthermore,there was a high gradient zone in the normalized correlation coefficient contour map with background values removed. The epicenters of the Yingjiang M_S6. 1 earthquake and the Ludian M_S6. 5 earthquake are located in the gradient zone or near the gradient zone.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51564037 and 51661011)the Innovation Fund Designated for Graduate Students of Jiangxi Province (Grant No. YC2016-B078)the Qing Jiang Scholar and the Start-up Fund of Jiangxi University of Science and Technology (Grant No. 3208600001)
文摘Much demanded and overused are the critical rare-earth elements such as Pr, Nd, Dy, and Tb with increasing need of Nd Fe B-type rare-earth permanent magnets in the enlarging application areas, developing new high-tech industries, and emerging cutting-age frontiers. The balance and efficient use of rare-earth resources comes into being the national strategy, national defense, and border safety for many major countries and regions in the world.（Nd,Ce）Fe B-based permanent magnetic materials, which can not only reduce cost but also offer a feasible way for integrated and effective utilization of rare earth resources,have received much attention in recent years. The existence of CeFe2 and the mixed valence state of Ce in Ce Fe B compound, the different metallurgy behavior and the particular processing as well as potential various magnetic-hardening mechanisms, however, make it quite different from Nd-based alloys.For instance, the coercivity of Ce-containing magnets in some certain composition range, is even higher than that of the counterpart pure Nd-based magnets though the Ce-containing magnets possess inferior intrinsic properties. Consequently, it is very important to design proper composition and structure, optimize processing, and analyze the mechanisms in depth for this kind of magnet. High performance and cost-effective magnets can be fabricated if we can make full use of the composition＇s inhomogeneous and abnormal coercivity variation of the Ce-containing permanent magnets. In this paper, we have summarized the phase structures, magnetic properties and microstructures of（Nd,Ce）Fe B-based permanent magnetic materials to shed light on further research and development of this type of so-called ＂gap magnet＂.
