NECP-SARAX是西安交通大学核工程计算物理实验室开发的先进反应堆中子学分析系统,近些年基于CEFR、PHENIX、SUPERPHENIX、JOYO MK-I、ZPR和ZPPR等反应堆开展了程序的验证与确认工作,计算结果表明:NECP-SARAX在快堆堆芯物理特性分析具有...NECP-SARAX是西安交通大学核工程计算物理实验室开发的先进反应堆中子学分析系统,近些年基于CEFR、PHENIX、SUPERPHENIX、JOYO MK-I、ZPR和ZPPR等反应堆开展了程序的验证与确认工作,计算结果表明:NECP-SARAX在快堆堆芯物理特性分析具有良好的性能。同时,利用上述反应堆中的燃料组件和控制棒组件,初步展现了截面计算程序TULIP在快谱问题计算分析上的精确性,但是仍然缺乏系统性地验证与确认。为了确认TULIP程序对于不同类型快谱问题的适用性,从国际临界安全基准评估项目中选取了147组临界实验装置进行计算分析,发现对于带有厚反射层的实验装置,TULIP程序计算k_(eff)和蒙特卡罗程序计算值的偏差超过10^(-2)。以HMF021-002实验装置构造均匀两核素问题展开研究,中等质量核素在非共振区表现出类似共振波动状的散射截面,对于使用大量结构材料的快谱系统,其非共振区类似共振波动截面的自屏效应变得不可忽略。针对此现象,对TULIP程序的共振计算策略和非共振区计算方法进行优化,采用超细群(Ultra Fine Group,UFG)的共振计算方法,对中等质量核素高装载量情况下非共振区类似共振波动状截面的自屏效应进行处理,改进程序后相应实验装置计算偏差降低到3×10^(-3)内,数值结果表明,改进后的TULIP程序对于快谱系统具有良好的计算分析能力。展开更多
Until now the genus Amana(Liliaceae),known as ’East Asian tulips’,has contained just seven species.In this study,a phylogenomic and integrative taxonomic approach was used to reveal two new species,Amana nanyueensis...Until now the genus Amana(Liliaceae),known as ’East Asian tulips’,has contained just seven species.In this study,a phylogenomic and integrative taxonomic approach was used to reveal two new species,Amana nanyueensis from Central China and A.tianmuensis from East China.A.nanyueensis resembles Amana edulis in possessing a densely villous-woolly bulb tunic and two opposite bracts,but differs in its leaves and anthers.Amana tianmuensis resembles Amana erythronioides in possessing three verticillate bracts and yellow anthers,but differs in aspects of its leaves and bulbs.These four species are clearly separated from each other in principal components analysis based on morphology.Phylogenomic analyses based on plastid CDS further support the species delimitation of A.nanyueensis and A.tianmuensis and suggests they are closely related to A.edulis.Cytological analysis shows that A.nanyueensis and A tianmuensis are both diploid(2n=2x=24),different from A edulis,which is either diploid(northern populations) or tetraploid(southern populations,2n=4x=48).The pollen morphology of A.nanyueensis is similar to other Amana species(single-groove germination aperture),but A.tianmuensis is quite different because of the presence of a sulcus membrane,which creates the illusion of double grooves.Ecological niche modelling also revealed a niche differentiation between A.edulis,A.nanyueensis and A.tianmuensis.展开更多
We report a case of a 63-year-old male who experienced an iatrogenic sigmoid perforation repaired combining three endoscopic techniques.The lesion was large and irregular with three discrete perforations,therefore,we ...We report a case of a 63-year-old male who experienced an iatrogenic sigmoid perforation repaired combining three endoscopic techniques.The lesion was large and irregular with three discrete perforations,therefore,we decided to close it by placing one clip per perforation,and then connecting all the clips with two endoloops.Finally we chose to use a fibrin glue injection to obtain a complete sealing.Four days after the colonoscopy the patient underwent a laparoscopic right hemicolectomy due to evidence of a large polyp of the caecum with high grade dysplasia and focal carcinoma in situ.Inspection of the sigma showed complete repair of the perforation.This report underlines how a conservative approach,together with a combination of various endoscopic techniques,can resolve complicated iatrogenic perforations of the colon.展开更多
文摘NECP-SARAX是西安交通大学核工程计算物理实验室开发的先进反应堆中子学分析系统,近些年基于CEFR、PHENIX、SUPERPHENIX、JOYO MK-I、ZPR和ZPPR等反应堆开展了程序的验证与确认工作,计算结果表明:NECP-SARAX在快堆堆芯物理特性分析具有良好的性能。同时,利用上述反应堆中的燃料组件和控制棒组件,初步展现了截面计算程序TULIP在快谱问题计算分析上的精确性,但是仍然缺乏系统性地验证与确认。为了确认TULIP程序对于不同类型快谱问题的适用性,从国际临界安全基准评估项目中选取了147组临界实验装置进行计算分析,发现对于带有厚反射层的实验装置,TULIP程序计算k_(eff)和蒙特卡罗程序计算值的偏差超过10^(-2)。以HMF021-002实验装置构造均匀两核素问题展开研究,中等质量核素在非共振区表现出类似共振波动状的散射截面,对于使用大量结构材料的快谱系统,其非共振区类似共振波动截面的自屏效应变得不可忽略。针对此现象,对TULIP程序的共振计算策略和非共振区计算方法进行优化,采用超细群(Ultra Fine Group,UFG)的共振计算方法,对中等质量核素高装载量情况下非共振区类似共振波动状截面的自屏效应进行处理,改进程序后相应实验装置计算偏差降低到3×10^(-3)内,数值结果表明,改进后的TULIP程序对于快谱系统具有良好的计算分析能力。
基金supported by the National Natural Science Foundation of China (Grant No.31970225)the Zhejiang Provincial Natural Science Foundation (Grant No.LY19C030007)theNSFC-NSF Dimensions of Biodiversity Program (Grant No.31461123001)。
文摘Until now the genus Amana(Liliaceae),known as ’East Asian tulips’,has contained just seven species.In this study,a phylogenomic and integrative taxonomic approach was used to reveal two new species,Amana nanyueensis from Central China and A.tianmuensis from East China.A.nanyueensis resembles Amana edulis in possessing a densely villous-woolly bulb tunic and two opposite bracts,but differs in its leaves and anthers.Amana tianmuensis resembles Amana erythronioides in possessing three verticillate bracts and yellow anthers,but differs in aspects of its leaves and bulbs.These four species are clearly separated from each other in principal components analysis based on morphology.Phylogenomic analyses based on plastid CDS further support the species delimitation of A.nanyueensis and A.tianmuensis and suggests they are closely related to A.edulis.Cytological analysis shows that A.nanyueensis and A tianmuensis are both diploid(2n=2x=24),different from A edulis,which is either diploid(northern populations) or tetraploid(southern populations,2n=4x=48).The pollen morphology of A.nanyueensis is similar to other Amana species(single-groove germination aperture),but A.tianmuensis is quite different because of the presence of a sulcus membrane,which creates the illusion of double grooves.Ecological niche modelling also revealed a niche differentiation between A.edulis,A.nanyueensis and A.tianmuensis.
文摘We report a case of a 63-year-old male who experienced an iatrogenic sigmoid perforation repaired combining three endoscopic techniques.The lesion was large and irregular with three discrete perforations,therefore,we decided to close it by placing one clip per perforation,and then connecting all the clips with two endoloops.Finally we chose to use a fibrin glue injection to obtain a complete sealing.Four days after the colonoscopy the patient underwent a laparoscopic right hemicolectomy due to evidence of a large polyp of the caecum with high grade dysplasia and focal carcinoma in situ.Inspection of the sigma showed complete repair of the perforation.This report underlines how a conservative approach,together with a combination of various endoscopic techniques,can resolve complicated iatrogenic perforations of the colon.
