The forest estate in south-west Zabaikalia, a territory included in the Lake Baikal catchment area, has been investigated. For this purpose we have used both data of our own studies and monitoring data of environmenta...The forest estate in south-west Zabaikalia, a territory included in the Lake Baikal catchment area, has been investigated. For this purpose we have used both data of our own studies and monitoring data of environmental protection bodies. It shows that in our study area, fires, fellings, entomo-parasites and air pollution are the major negative factors affecting the state of the forest. In the period from 2003 to 2008 fires were registered in the area of over 500 thousand ha, pest foci in the forests covering an area of over 330 thousand ha, where almost 5 million m3wood was cut in an area of about 43 thousand ha. The total area of forests in our study affected by air pollution amounts to about 700 thousand ha. According to the results, forest pollution in the territory is concentrated in the vicinity of large-scale industrial complexes, for distances up to about 40 km. The total area of forests weakened by air pollution amounts to about 2 million ha.展开更多
The electronic structure of iron-pnictide compound superconductor Ba_2Ti_2Fe_2As_4O, which has metallic intermediate Ti_2O layers, is studied using angle-resolved photoemission spectroscopy. The Ti-related bands show ...The electronic structure of iron-pnictide compound superconductor Ba_2Ti_2Fe_2As_4O, which has metallic intermediate Ti_2O layers, is studied using angle-resolved photoemission spectroscopy. The Ti-related bands show a‘peak-dip-hump＇ line shape with two branches of dispersion associated with the polaronic states at temperatures below around 120 K. This change in the spectra occurs along with the resistivity anomaly that was not clearly understood in a previous study. Moreover, an energy gap induced by the superconducting proximity effect opens in the polaronic bands at temperatures below T_c（~21 K）. Our study provides the spectroscopic evidence that superconductivity coexists with polarons in the same bands near the Fermi level, which provides a suitable platform to study interactions between charge, lattice and spin freedoms in a correlated system.展开更多
利用第一性原理密度泛函理论,计算了不同浓度Y掺杂Ba Ti O3的电子结构和光学性质.计算结果表明:掺杂Y元素后,体系的禁带宽度增大,能态密度向低能方向移动,费米能级进入导带,体现出n型半导体的特征,改善了Ba Ti O3的导电性.在光学性质上...利用第一性原理密度泛函理论,计算了不同浓度Y掺杂Ba Ti O3的电子结构和光学性质.计算结果表明:掺杂Y元素后,体系的禁带宽度增大,能态密度向低能方向移动,费米能级进入导带,体现出n型半导体的特征,改善了Ba Ti O3的导电性.在光学性质上,无入射光情况下的纯Ba Ti O3静态介电常数值为4.69,掺杂后静态介电常数改变比较大,尤其是高浓度掺杂后远远大于纯Ba Ti O3,这意味着其可能是一种新的介电材料.掺杂后,体系的能量损失峰明显向低能区移动,随着掺杂浓度的增大,能量损失强度也有所增加.展开更多
基金supported by the Siberian Branch of the Russian Academy of Sciences (No.17)
文摘The forest estate in south-west Zabaikalia, a territory included in the Lake Baikal catchment area, has been investigated. For this purpose we have used both data of our own studies and monitoring data of environmental protection bodies. It shows that in our study area, fires, fellings, entomo-parasites and air pollution are the major negative factors affecting the state of the forest. In the period from 2003 to 2008 fires were registered in the area of over 500 thousand ha, pest foci in the forests covering an area of over 330 thousand ha, where almost 5 million m3wood was cut in an area of about 43 thousand ha. The total area of forests in our study affected by air pollution amounts to about 700 thousand ha. According to the results, forest pollution in the territory is concentrated in the vicinity of large-scale industrial complexes, for distances up to about 40 km. The total area of forests weakened by air pollution amounts to about 2 million ha.
基金Supported by the National Basic Research Program of China under Grant Nos 2013CB921700,2015CB921300 and2015CB921301the National Natural Science Foundation of China under Grant Nos 11234014,11622435,11274362,11674371 and11474340+1 种基金the National Key Research and Development Program of China under Grant Nos 2016YFA0300300,2016YFA0300600,2016YFA0401000 and 2016YFA0400902the Open Large Infrastructure Research of Chinese Academy of Sciences,and the Pioneer Hundred Talents Program(Type C)of Chinese Academy of Sciences
文摘The electronic structure of iron-pnictide compound superconductor Ba_2Ti_2Fe_2As_4O, which has metallic intermediate Ti_2O layers, is studied using angle-resolved photoemission spectroscopy. The Ti-related bands show a‘peak-dip-hump＇ line shape with two branches of dispersion associated with the polaronic states at temperatures below around 120 K. This change in the spectra occurs along with the resistivity anomaly that was not clearly understood in a previous study. Moreover, an energy gap induced by the superconducting proximity effect opens in the polaronic bands at temperatures below T_c（~21 K）. Our study provides the spectroscopic evidence that superconductivity coexists with polarons in the same bands near the Fermi level, which provides a suitable platform to study interactions between charge, lattice and spin freedoms in a correlated system.
基金Supported by the National Natural Science Foundation of China(11204001,11174004)Anhui Provincial Natural Science Foundation(1208085QA07,1308085MA04)+2 种基金the Higher Educational Natural Science Foundation of Anhui Province(KJ2013A031)Anhui University Scientific Research Fund(201410357005,KYXL2013009)“211 Project”of Anhui University(SZJYKC2013020,XJGXKC1401)
文摘利用第一性原理密度泛函理论,计算了不同浓度Y掺杂Ba Ti O3的电子结构和光学性质.计算结果表明:掺杂Y元素后,体系的禁带宽度增大,能态密度向低能方向移动,费米能级进入导带,体现出n型半导体的特征,改善了Ba Ti O3的导电性.在光学性质上,无入射光情况下的纯Ba Ti O3静态介电常数值为4.69,掺杂后静态介电常数改变比较大,尤其是高浓度掺杂后远远大于纯Ba Ti O3,这意味着其可能是一种新的介电材料.掺杂后,体系的能量损失峰明显向低能区移动,随着掺杂浓度的增大,能量损失强度也有所增加.
