高能伽马射线探测是研究极端天体物理的主要途径之一.空间高能伽马射线探测具有覆盖波段宽、时间连续性好、能量分辨率高等突出优势.在成功研发并运行我国首颗天文卫星—"悟空"号(DArk Matter Particle Explorer,DAMPE)的基础...高能伽马射线探测是研究极端天体物理的主要途径之一.空间高能伽马射线探测具有覆盖波段宽、时间连续性好、能量分辨率高等突出优势.在成功研发并运行我国首颗天文卫星—"悟空"号(DArk Matter Particle Explorer,DAMPE)的基础上,紫金山天文台联合国内的多家单位提议研制甚大面积伽马射线空间望远镜(Very Large Areagamma-ray Space Telescope,VLAST),该望远镜在GeV-TeV能段接受度高达10 m^(2)·sr,并具有强的MeV-GeV波段探测能力,其综合性能预期比费米卫星的大面积伽马望远镜(Fermi-LAT(Large Area Telescope))提升10倍之上.重点介绍了VLAST的主要科学目标,探测器的初步配置及预期性能指标.展开更多
文章旨在研究牛油火锅底料和清油火锅底料挥发性成分的差异性。首先采用固相微萃取法收集14种市售牛油和清油火锅底料的挥发性成分,利用气相色谱-质谱联用进行分析和鉴定。然后采用内标法对挥发性成分进行半定量分析,并进行主成分分析(p...文章旨在研究牛油火锅底料和清油火锅底料挥发性成分的差异性。首先采用固相微萃取法收集14种市售牛油和清油火锅底料的挥发性成分,利用气相色谱-质谱联用进行分析和鉴定。然后采用内标法对挥发性成分进行半定量分析,并进行主成分分析(principal component analysis,PCA)和正交偏最小二乘法-判别分析(orthogonal partial least squares-discriminant analysis,OPLS-DA)。最后综合变量重要性投影(variable importance in projection,VIP)和显著性检验P值,筛选牛油与清油火锅底料的差异性挥发性成分。结果表明,牛油和清油火锅底料中的差异性挥发性成分为:(Z)-2-壬烯醛、β-水芹烯、β-月桂烯、香芹酮、D-柠檬烯、乙酸芳樟酯、(E)-2-十二烯醛、(E)-2-十一烯醛、茴香脑、芳樟醇、α-侧柏烯。OPLS-DA能够用于牛油和清油火锅底料的差异性分析,并筛选出差异性挥发性成分。展开更多
This paper discusses four Imagination Matrices of Ancient Chinese Myth.The first one is“Heaven Ladder”,which is believed to have the function of traffic means between upper universe and middle one.And Jianmu is a sp...This paper discusses four Imagination Matrices of Ancient Chinese Myth.The first one is“Heaven Ladder”,which is believed to have the function of traffic means between upper universe and middle one.And Jianmu is a special Heaven Ladder which is used especially by gods.The second one is the“Capital of God on the Earth”,which is regarded as the reign center of God on the earth.It located at the Mount Kunlun in the northwest of China.Opposite to the lofty Mount Kunlun into heaven,Gui Xu,the third matrix,is a bottomless valley in the east of the Bohai Sea.Gui Xu is another center for gods’activities.The last one is Huangquan Road,the lower universe,which means the world after death for the ancient people.展开更多
文摘高能伽马射线探测是研究极端天体物理的主要途径之一.空间高能伽马射线探测具有覆盖波段宽、时间连续性好、能量分辨率高等突出优势.在成功研发并运行我国首颗天文卫星—"悟空"号(DArk Matter Particle Explorer,DAMPE)的基础上,紫金山天文台联合国内的多家单位提议研制甚大面积伽马射线空间望远镜(Very Large Areagamma-ray Space Telescope,VLAST),该望远镜在GeV-TeV能段接受度高达10 m^(2)·sr,并具有强的MeV-GeV波段探测能力,其综合性能预期比费米卫星的大面积伽马望远镜(Fermi-LAT(Large Area Telescope))提升10倍之上.重点介绍了VLAST的主要科学目标,探测器的初步配置及预期性能指标.
文摘文章旨在研究牛油火锅底料和清油火锅底料挥发性成分的差异性。首先采用固相微萃取法收集14种市售牛油和清油火锅底料的挥发性成分,利用气相色谱-质谱联用进行分析和鉴定。然后采用内标法对挥发性成分进行半定量分析,并进行主成分分析(principal component analysis,PCA)和正交偏最小二乘法-判别分析(orthogonal partial least squares-discriminant analysis,OPLS-DA)。最后综合变量重要性投影(variable importance in projection,VIP)和显著性检验P值,筛选牛油与清油火锅底料的差异性挥发性成分。结果表明,牛油和清油火锅底料中的差异性挥发性成分为:(Z)-2-壬烯醛、β-水芹烯、β-月桂烯、香芹酮、D-柠檬烯、乙酸芳樟酯、(E)-2-十二烯醛、(E)-2-十一烯醛、茴香脑、芳樟醇、α-侧柏烯。OPLS-DA能够用于牛油和清油火锅底料的差异性分析,并筛选出差异性挥发性成分。
文摘This paper discusses four Imagination Matrices of Ancient Chinese Myth.The first one is“Heaven Ladder”,which is believed to have the function of traffic means between upper universe and middle one.And Jianmu is a special Heaven Ladder which is used especially by gods.The second one is the“Capital of God on the Earth”,which is regarded as the reign center of God on the earth.It located at the Mount Kunlun in the northwest of China.Opposite to the lofty Mount Kunlun into heaven,Gui Xu,the third matrix,is a bottomless valley in the east of the Bohai Sea.Gui Xu is another center for gods’activities.The last one is Huangquan Road,the lower universe,which means the world after death for the ancient people.
