Chemical and biochemical analysis methods were used to monitor the vedations of nitrogen nutrient among the dominance trees species in secondary succession process of the mixed broad - leaved/Korean pine forest on Cha...Chemical and biochemical analysis methods were used to monitor the vedations of nitrogen nutrient among the dominance trees species in secondary succession process of the mixed broad - leaved/Korean pine forest on Changbai Mountains, Northeast China. Amounts of total nitrogen, anunonium and NRA in soils of virgin broad-leaved/Korean pine forest which is in climax were higher than those of secondary birch forests those are in succession Stage. The amount of nitrate was in the other hand. In climax, dominance trees species are tolerant mesophytic trees such as Pinus Koraiensis, Tilia amurensis, Acer mono and also Fraxinus mandshurica, they are all ammonium + nitrate adapted species, but they show a preference for the anunonium rather than those of the pioneer trees species in secondary birch forest, such as Populus davidiava and Betula platyphylla. Because they have more ammonium in their leaves and roots, especially Pinus koraiensis. Populus davidvana and Betula plaaphlla are intolerant trees, amounts of nitrate and total nitrogen is higher in their leaves and roots and also NRA in their leaves, so they preference for the nitrate rather than the others.In secondary birch forest, the regeneration trees species adapt their nitroggn nutrient to the variation of nitrogen nutrient situation in soil, finally they could survival well and the secondary birch forest would succession to climax. In climax, dominance trees species adapt their Nitrogen nutrient to the situation in soil and there are not strong competition in nitrogen nutrient among them, so they can coexist well and keep the climax as stable vegetation.展开更多
[Objective] The study aimed to analyze vegetation succession process under groundwater mining conditions in Subei Lake watershed. [ Method] A succession model for vegetation and burial depth of groundwater level was c...[Objective] The study aimed to analyze vegetation succession process under groundwater mining conditions in Subei Lake watershed. [ Method] A succession model for vegetation and burial depth of groundwater level was constructed based on field survey, and it was used to pre- dict the vegetation succession rules and process according to the changes in burial depth of groundwater level in Subei Lake watershed under groundwater exploitation. [ Result~ In Subei Lake watershed, aquatic vegetation was most closely related to burial depth of groundwater level, fol- lowed by mesophytic vegetation, while psammophilous and xerophytic vegetation did not have obvious relation with burial depth of groundwater lev- el. When burial depth of groundwater level was small, dominant plants grew well, but they grew worse or died with the increase in burial depth of groundwater level. As the groundwater level fell constantly, burial depth of groundwater level went up, and vegetation succession would occur grad- ually from aquatic vegetation to mesophytic and xerophytic vegetation, from Carex L. and Iris ensata Thunb shoaly land to Achnatherum splendens shoaly lands, from Salix psammophila shrubs to Artemisia desterorum Spreng and Caragana korshinskii shrubs, and from Populus simonii to Salix matsudana. [Condusion] The research could provide scientific references for studying the relationship between groundwater resources and ecological environment in Subei Lake basin.展开更多
Based on sounding and ground observation data,GPS/MET and FY-2 E satellite data,NCEP/NCAR reanalysis data（ 1°× 1°）,the formation mechanisms of two successive heavy rainfall processes on the edge of th...Based on sounding and ground observation data,GPS/MET and FY-2 E satellite data,NCEP/NCAR reanalysis data（ 1°× 1°）,the formation mechanisms of two successive heavy rainfall processes on the edge of the subtropical high were analyzed. The results showed that the two heavy rainfall processes were caused by weak westerly troughs on the edge of the subtropical high at 500 h Pa,and there was strong southwest jet stream at 850-700 h Pa. As the low-level southwest jet stream intensified and moved northwards,heavy rainfall began. When the jet stream weakened,heavy rainfall ended. The heavy rainfall areas had good consistency with the high-value areas of CAPE,the high-value tongue of low-level water vapor flux,water vapor convergence center and warm advection center. Water vapor monitoring by GPS/MET had certain denotative meaning to the short-term prediction of heavy rainfall. The minimum TBB of convective cloud clusters was between-62 and-78 ℃,and the corresponding hourly maximum precipitation was 40-90 mm. In the heavy rainfall process,mesoscale vortexes occurred at 850 h Pa and below,but the scale was small,with weak low pressure but significant cyclonic circulation. The most intense rainfall was generated at the center of warm advection in the southeast of the vortex center at 925 h Pa. In the first heavy rainfall process,the mesoscale vortexes moved less,while strong rainfall was induced by strong upward movement in the southeast of the vortexes. In the second heavy rainfall process,low-level cold air invaded from the northwest into the vortexes to form cyclones and moved northeastwards. Heavy rainfall happened in the warm zone in front of cold front,and convective instability energy was high. Rainfall intensity was high,and rainfall range was large.展开更多
The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performa...The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients.展开更多
文摘Chemical and biochemical analysis methods were used to monitor the vedations of nitrogen nutrient among the dominance trees species in secondary succession process of the mixed broad - leaved/Korean pine forest on Changbai Mountains, Northeast China. Amounts of total nitrogen, anunonium and NRA in soils of virgin broad-leaved/Korean pine forest which is in climax were higher than those of secondary birch forests those are in succession Stage. The amount of nitrate was in the other hand. In climax, dominance trees species are tolerant mesophytic trees such as Pinus Koraiensis, Tilia amurensis, Acer mono and also Fraxinus mandshurica, they are all ammonium + nitrate adapted species, but they show a preference for the anunonium rather than those of the pioneer trees species in secondary birch forest, such as Populus davidiava and Betula platyphylla. Because they have more ammonium in their leaves and roots, especially Pinus koraiensis. Populus davidvana and Betula plaaphlla are intolerant trees, amounts of nitrate and total nitrogen is higher in their leaves and roots and also NRA in their leaves, so they preference for the nitrate rather than the others.In secondary birch forest, the regeneration trees species adapt their nitroggn nutrient to the variation of nitrogen nutrient situation in soil, finally they could survival well and the secondary birch forest would succession to climax. In climax, dominance trees species adapt their Nitrogen nutrient to the situation in soil and there are not strong competition in nitrogen nutrient among them, so they can coexist well and keep the climax as stable vegetation.
基金Supported by the Large Survey Project of Ministry of Land and Resources,China (1212010734002)
文摘[Objective] The study aimed to analyze vegetation succession process under groundwater mining conditions in Subei Lake watershed. [ Method] A succession model for vegetation and burial depth of groundwater level was constructed based on field survey, and it was used to pre- dict the vegetation succession rules and process according to the changes in burial depth of groundwater level in Subei Lake watershed under groundwater exploitation. [ Result~ In Subei Lake watershed, aquatic vegetation was most closely related to burial depth of groundwater level, fol- lowed by mesophytic vegetation, while psammophilous and xerophytic vegetation did not have obvious relation with burial depth of groundwater lev- el. When burial depth of groundwater level was small, dominant plants grew well, but they grew worse or died with the increase in burial depth of groundwater level. As the groundwater level fell constantly, burial depth of groundwater level went up, and vegetation succession would occur grad- ually from aquatic vegetation to mesophytic and xerophytic vegetation, from Carex L. and Iris ensata Thunb shoaly land to Achnatherum splendens shoaly lands, from Salix psammophila shrubs to Artemisia desterorum Spreng and Caragana korshinskii shrubs, and from Populus simonii to Salix matsudana. [Condusion] The research could provide scientific references for studying the relationship between groundwater resources and ecological environment in Subei Lake basin.
基金Supported by Special Project for Development of Core Forecast Business of China Meteorological Administration(CMAHX20160208)Special Project for Forecasters of China Meteorological Administration(CMAYBY2013-040)+1 种基金Scientific Research Project(2013sdqx01,2014sdqxm20)Open Research Foundation of Numerical Weather Prediction Application Technology of Shandong Institute of Meteorological Sciences(SDQXKF2014Z05)
文摘Based on sounding and ground observation data,GPS/MET and FY-2 E satellite data,NCEP/NCAR reanalysis data（ 1°× 1°）,the formation mechanisms of two successive heavy rainfall processes on the edge of the subtropical high were analyzed. The results showed that the two heavy rainfall processes were caused by weak westerly troughs on the edge of the subtropical high at 500 h Pa,and there was strong southwest jet stream at 850-700 h Pa. As the low-level southwest jet stream intensified and moved northwards,heavy rainfall began. When the jet stream weakened,heavy rainfall ended. The heavy rainfall areas had good consistency with the high-value areas of CAPE,the high-value tongue of low-level water vapor flux,water vapor convergence center and warm advection center. Water vapor monitoring by GPS/MET had certain denotative meaning to the short-term prediction of heavy rainfall. The minimum TBB of convective cloud clusters was between-62 and-78 ℃,and the corresponding hourly maximum precipitation was 40-90 mm. In the heavy rainfall process,mesoscale vortexes occurred at 850 h Pa and below,but the scale was small,with weak low pressure but significant cyclonic circulation. The most intense rainfall was generated at the center of warm advection in the southeast of the vortex center at 925 h Pa. In the first heavy rainfall process,the mesoscale vortexes moved less,while strong rainfall was induced by strong upward movement in the southeast of the vortexes. In the second heavy rainfall process,low-level cold air invaded from the northwest into the vortexes to form cyclones and moved northeastwards. Heavy rainfall happened in the warm zone in front of cold front,and convective instability energy was high. Rainfall intensity was high,and rainfall range was large.
文摘The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients.
