2020年全国Ⅰ卷的语法填空,10道题有8道题均在长难句中。只有找出句子主干,剔除干扰成分,理解好长难句,才可以很好地完成这8道题。1.The unmaned Chang’e--4 probe(探测器)--the name was inspired by an ancient Chinese moon goddess...2020年全国Ⅰ卷的语法填空,10道题有8道题均在长难句中。只有找出句子主干,剔除干扰成分,理解好长难句,才可以很好地完成这8道题。1.The unmaned Chang’e--4 probe(探测器)--the name was inspired by an ancient Chinese moon goddess 61(touch)down last week in the South Pole-Aitken basin.分析:61题,能正确填出touched的考生不是很多。展开更多
Technological development has led to the emergence of new substances with many different purposes generating a new profile of pollutants in waterways. Among these, endocrine disruptors, such as 17EE （17ct-ethinylestr...Technological development has led to the emergence of new substances with many different purposes generating a new profile of pollutants in waterways. Among these, endocrine disruptors, such as 17EE （17ct-ethinylestradiol）, are of great importance due to their wide application and harmful consequences to the environment, human health and animals. The inefficiency of most water treatment processes in withdrawing such substances poses a global concern for the development of effective and environmentally clean methods. The electrochemical remediation processes appear as a powerful and ＂green＂ alternative for waste removal of organic or inorganic pollutants from complex environments, such as geosphere and hydrosphere. The research focus in this field is mostly related to the optimization of electronic devices with higher （photo） catalytic efficiency, whereas the starting material remains based on metal and carbon conventional electrodes. In the present study, the anodic removal process of 17ct-ethinylestradiol at carbon cardboards was investigated in stationary and hydrodynamic conditions. The influence of pH and applied potential were evaluated, always taking into account the transposition of scale and environmental aspects. Thus, the principle of hormone removal showed to be strictly related to such parameters. It was observed that mild alkaline medium favors the anodic oxidation, whereas neutral and mild acid ones lead to higher adsorption at carbon surface. Also, when the applied potential was higher than 1.25 V, the electrochemical oxidation rate increased, and the adsorption was decreased. Furthermore, the removal efficiency of ! 7EE showed to be lower, the flow rate was higher.展开更多
This paper derives an approximate formula for probability density function(PDF) of received signal-to-interference-and-noise ratio(SINR) at user terminal when matched filter(MF) is adopted at a base station(BS).This d...This paper derives an approximate formula for probability density function(PDF) of received signal-to-interference-and-noise ratio(SINR) at user terminal when matched filter(MF) is adopted at a base station(BS).This distribution of SINR can be used to make an analysis of average sum-rate,outage probability,and symbol error rate of massive MIMO downlink with MF at BS.From simulation,it is found that the derived approximate analytical expression for PDF of SINR is consistent with the simulated exact PDF from the definition of SINR in medium-scale and large-scale MIMO systems.展开更多
After being kept in captivity and isolated from natural predators for more than 1,200 years, P6re David＇s deer has been reintroduced in China and now occurs in a reserve where human activity is the only potential thr...After being kept in captivity and isolated from natural predators for more than 1,200 years, P6re David＇s deer has been reintroduced in China and now occurs in a reserve where human activity is the only potential threat. Antipredator vigilance i~ an important component of survival for many prey animals in their natural habitat. Do deer still adjust vigilance as a function of risk after such a long period of relaxed predation pressure？ Here, we examined vigilance levels in P6re David＇s deer groups as a function of group size, sex and level of human disturbance. The results showed that individual vigilance significantly decreased with group size in all-female groups but not in all-males or mixed-sex groups. In rutting season, males compete with one another and harass females, and we argue that vigilance is partly aimed at threatening males and that such vigilance increases with group size. This explains why overall vigilance did not vary with group size for males in general and for females in mixed-sex groups. Vigilance increased in more disturbed areas but in in male deer only. The results indicate that despite relaxed predation pressure over centuries, P6re David＇s deer can still adjust antipredator responses as a function of perceived risk. Such information may become useful in the rewilding programme now under way for this species in China [Current Zoology 59 （2）： 265-270, 2013].展开更多
Massive human interference in natural ecosystems is resulting in a few ＂winners＂ and many ＂losers＂. However, the drivers of this winner-loser replacement pattern remain poorly understood. The aim of the study repo...Massive human interference in natural ecosystems is resulting in a few ＂winners＂ and many ＂losers＂. However, the drivers of this winner-loser replacement pattern remain poorly understood. The aim of the study reported here was to identify winners among the tree flora of Xishuangbanna and compare their functional traits, specific leaf area （SLA）, wood density （WD）, seed mass （SM） and maximum height （MH） with previously identified losers （i.e., endangered species）. Fifteen native tree species were identified as winners from expert opinion, plot-based surveys of secondary forests and plotless surveys along roads. Twelve endangered tree species for which trait information could be obtained were used for comparison. Traits were compared with a Wilcoxon rank-sum test. Winners had significantly higher SLA, but lower WD. SM and MH did not differ significantly between groups. When the effects of phylogeny were removed by using phylogenetic generalized least squares, the difference in SLA became marginally insignificant. Principal component analysis resulted in two overlapping groups, showing that the selected traits were insufficient to distinguish winners and losers. Our results suggest that the ＂few winners, many losers＂ paradigm applies to trees in Xishuangbanna, with15 species accounting for most trees in the disturbed habitats sampled.展开更多
文摘2020年全国Ⅰ卷的语法填空,10道题有8道题均在长难句中。只有找出句子主干,剔除干扰成分,理解好长难句,才可以很好地完成这8道题。1.The unmaned Chang’e--4 probe(探测器)--the name was inspired by an ancient Chinese moon goddess 61(touch)down last week in the South Pole-Aitken basin.分析:61题,能正确填出touched的考生不是很多。
文摘Technological development has led to the emergence of new substances with many different purposes generating a new profile of pollutants in waterways. Among these, endocrine disruptors, such as 17EE （17ct-ethinylestradiol）, are of great importance due to their wide application and harmful consequences to the environment, human health and animals. The inefficiency of most water treatment processes in withdrawing such substances poses a global concern for the development of effective and environmentally clean methods. The electrochemical remediation processes appear as a powerful and ＂green＂ alternative for waste removal of organic or inorganic pollutants from complex environments, such as geosphere and hydrosphere. The research focus in this field is mostly related to the optimization of electronic devices with higher （photo） catalytic efficiency, whereas the starting material remains based on metal and carbon conventional electrodes. In the present study, the anodic removal process of 17ct-ethinylestradiol at carbon cardboards was investigated in stationary and hydrodynamic conditions. The influence of pH and applied potential were evaluated, always taking into account the transposition of scale and environmental aspects. Thus, the principle of hormone removal showed to be strictly related to such parameters. It was observed that mild alkaline medium favors the anodic oxidation, whereas neutral and mild acid ones lead to higher adsorption at carbon surface. Also, when the applied potential was higher than 1.25 V, the electrochemical oxidation rate increased, and the adsorption was decreased. Furthermore, the removal efficiency of ! 7EE showed to be lower, the flow rate was higher.
基金Supported by the National Natural Science Foundation of China(No.61271230,61301107)the Fundamental Research Funds for the Central Universities(No.30920130122004)Open Research Fund of National Mobile Communications Research Laboratory,Southeast University(No.2013D02)
文摘This paper derives an approximate formula for probability density function(PDF) of received signal-to-interference-and-noise ratio(SINR) at user terminal when matched filter(MF) is adopted at a base station(BS).This distribution of SINR can be used to make an analysis of average sum-rate,outage probability,and symbol error rate of massive MIMO downlink with MF at BS.From simulation,it is found that the derived approximate analytical expression for PDF of SINR is consistent with the simulated exact PDF from the definition of SINR in medium-scale and large-scale MIMO systems.
基金Acknowledgements Financial support for this work was provided by the National Natural Science Foundation of China （No. 31000174 ＆ No. Jl103512）. We thank Prof. Ding Yuhua and other staff members at Dafeng Milu National Natural Reserve for supporting our field research in the reserve. We also thank Xianlong Li, Rongrong Wang, Jia He, Dameng Li, Ruonan Jia, Yilei Hua, and Long Wang for help with the field work, and Chen Ge and Cheng Huang for useful discussions.
文摘After being kept in captivity and isolated from natural predators for more than 1,200 years, P6re David＇s deer has been reintroduced in China and now occurs in a reserve where human activity is the only potential threat. Antipredator vigilance i~ an important component of survival for many prey animals in their natural habitat. Do deer still adjust vigilance as a function of risk after such a long period of relaxed predation pressure？ Here, we examined vigilance levels in P6re David＇s deer groups as a function of group size, sex and level of human disturbance. The results showed that individual vigilance significantly decreased with group size in all-female groups but not in all-males or mixed-sex groups. In rutting season, males compete with one another and harass females, and we argue that vigilance is partly aimed at threatening males and that such vigilance increases with group size. This explains why overall vigilance did not vary with group size for males in general and for females in mixed-sex groups. Vigilance increased in more disturbed areas but in in male deer only. The results indicate that despite relaxed predation pressure over centuries, P6re David＇s deer can still adjust antipredator responses as a function of perceived risk. Such information may become useful in the rewilding programme now under way for this species in China [Current Zoology 59 （2）： 265-270, 2013].
基金supported by the 1000 Talents Program(WQ20110491035)
文摘Massive human interference in natural ecosystems is resulting in a few ＂winners＂ and many ＂losers＂. However, the drivers of this winner-loser replacement pattern remain poorly understood. The aim of the study reported here was to identify winners among the tree flora of Xishuangbanna and compare their functional traits, specific leaf area （SLA）, wood density （WD）, seed mass （SM） and maximum height （MH） with previously identified losers （i.e., endangered species）. Fifteen native tree species were identified as winners from expert opinion, plot-based surveys of secondary forests and plotless surveys along roads. Twelve endangered tree species for which trait information could be obtained were used for comparison. Traits were compared with a Wilcoxon rank-sum test. Winners had significantly higher SLA, but lower WD. SM and MH did not differ significantly between groups. When the effects of phylogeny were removed by using phylogenetic generalized least squares, the difference in SLA became marginally insignificant. Principal component analysis resulted in two overlapping groups, showing that the selected traits were insufficient to distinguish winners and losers. Our results suggest that the ＂few winners, many losers＂ paradigm applies to trees in Xishuangbanna, with15 species accounting for most trees in the disturbed habitats sampled.
