In this study,single Doppler radar data were used to examine the structure and evolution of a high precipitation（HP） supercell embedded in a cold front near Jianyang,Fujian Province on 12 April 2003.The synoptic env...In this study,single Doppler radar data were used to examine the structure and evolution of a high precipitation（HP） supercell embedded in a cold front near Jianyang,Fujian Province on 12 April 2003.The synoptic environment was characterized by high humidity at low levels,moderate CAPE（convective available potential energy;1601 J kg^（-1））,moderate wind shear（22 m s^（-1） in 0-5 km）,and veering of the horizontal winds with height,similar to those HP supercells previously observed in midlatitudes.In addition,the calculated bulk Richardson number was only 16,suggesting favorable environmental conditions for supercell development. The documented storm was located at the leading edge of a squall line.It was initiated from a single cell at 0732 UTC.It evolved into a bow shape gradually,and then split into two separate storms along the storm motion direction through the apex of the bow echo.The left-moving storm dissipated rapidly, but the right-moving storm strengthened and evolved into an HP supercell,lasting for more than 1 h.The radar reflectivity of the HP supercell during its mature stage showed a typical low-level hook echo at the front flank of the storm with its maximum reflectivity beyond 70 dBZ.Above the hook echo,an elevated maximum reflectivity core accompanied by a bounded weak-echo region（BWER） and a down-shear echo overhanging aloft were clearly identified.The elevated BWER,marked by 40-50-dBZ reflectivity values,was surrounded by values of 60-70 dBZ.A well-defined mesocyclone lasted about 1 h and was collocated with the low-level WER and middle-level BWER.The radar-estimated time-height profiles of mesocyclone rotational velocity and diameter indicated that this mesocyclone formed initially at middle level,then deepened and strengthened rapidly with the vertical depth deeper than 8 km and rotational velocity stronger than 24 m s^（-1） at the mature stage,and later decayed rapidly.The GBVTD（ground-based velocity track display）-derived primary circulation showed that the maxi展开更多
目的:优选分离冬凌草多糖的方法,探究不同分离方法对冬凌草多糖分离效果的影响。方法:分别以DEAE-Sepharose Fast Flow(Cl-型)弱极性阴离子交换层析法、乙醇分级醇析法对冬凌草粗多糖进行分离纯化,以不同分离组分中多糖含量及其免疫活...目的:优选分离冬凌草多糖的方法,探究不同分离方法对冬凌草多糖分离效果的影响。方法:分别以DEAE-Sepharose Fast Flow(Cl-型)弱极性阴离子交换层析法、乙醇分级醇析法对冬凌草粗多糖进行分离纯化,以不同分离组分中多糖含量及其免疫活性比较优选冬凌草粗多糖的分离工艺。结果:DEAE-Sepharose Fast Flow(Cl-型)弱极性阴离子交换层析法分离得到5个组分,通过乙醇分级醇沉初步得到4个冬凌草多糖组分,前者分离产品纯度较高,而后者产品在体外小鼠脾淋巴T细胞的增殖实验中表现出较强生物活性。结论:为进一步研究冬凌草多糖的生物活性,可选用乙醇分级醇沉法对冬凌草多糖进行分离纯化。展开更多
基金Supported by the National Special Fund for Meteorology(GYHY200706033)National Natural Science Foundation of China under Grant Nos.40505004,40405012,and 40333025+1 种基金National Fundamental Research"973"Program of China(2004CB418301) the Natioual Meteorological Center of China TIGGE Program(GYHY(QX) 2007-232 6-1)
文摘In this study,single Doppler radar data were used to examine the structure and evolution of a high precipitation（HP） supercell embedded in a cold front near Jianyang,Fujian Province on 12 April 2003.The synoptic environment was characterized by high humidity at low levels,moderate CAPE（convective available potential energy;1601 J kg^（-1））,moderate wind shear（22 m s^（-1） in 0-5 km）,and veering of the horizontal winds with height,similar to those HP supercells previously observed in midlatitudes.In addition,the calculated bulk Richardson number was only 16,suggesting favorable environmental conditions for supercell development. The documented storm was located at the leading edge of a squall line.It was initiated from a single cell at 0732 UTC.It evolved into a bow shape gradually,and then split into two separate storms along the storm motion direction through the apex of the bow echo.The left-moving storm dissipated rapidly, but the right-moving storm strengthened and evolved into an HP supercell,lasting for more than 1 h.The radar reflectivity of the HP supercell during its mature stage showed a typical low-level hook echo at the front flank of the storm with its maximum reflectivity beyond 70 dBZ.Above the hook echo,an elevated maximum reflectivity core accompanied by a bounded weak-echo region（BWER） and a down-shear echo overhanging aloft were clearly identified.The elevated BWER,marked by 40-50-dBZ reflectivity values,was surrounded by values of 60-70 dBZ.A well-defined mesocyclone lasted about 1 h and was collocated with the low-level WER and middle-level BWER.The radar-estimated time-height profiles of mesocyclone rotational velocity and diameter indicated that this mesocyclone formed initially at middle level,then deepened and strengthened rapidly with the vertical depth deeper than 8 km and rotational velocity stronger than 24 m s^（-1） at the mature stage,and later decayed rapidly.The GBVTD（ground-based velocity track display）-derived primary circulation showed that the maxi
文摘目的:优选分离冬凌草多糖的方法,探究不同分离方法对冬凌草多糖分离效果的影响。方法:分别以DEAE-Sepharose Fast Flow(Cl-型)弱极性阴离子交换层析法、乙醇分级醇析法对冬凌草粗多糖进行分离纯化,以不同分离组分中多糖含量及其免疫活性比较优选冬凌草粗多糖的分离工艺。结果:DEAE-Sepharose Fast Flow(Cl-型)弱极性阴离子交换层析法分离得到5个组分,通过乙醇分级醇沉初步得到4个冬凌草多糖组分,前者分离产品纯度较高,而后者产品在体外小鼠脾淋巴T细胞的增殖实验中表现出较强生物活性。结论:为进一步研究冬凌草多糖的生物活性,可选用乙醇分级醇沉法对冬凌草多糖进行分离纯化。
