White-light （WL） flares have been observed and studied for more than a century since their first discovery. However, some fundamental physics behind the brilliant emission remains highly controversial. One of the im...White-light （WL） flares have been observed and studied for more than a century since their first discovery. However, some fundamental physics behind the brilliant emission remains highly controversial. One of the important facts in addressing the flare energetics is the spatio-temporal correlation between the WL emission and the hard X-ray （HXR） radiation, presumably suggesting that energetic electrons are the energy sources. In this study, we present a statistical analysis of 25 strong flares （〉M5） observed simultaneously by the Helioseismic and Magnetic Imager （HMI）, on board the Solar Dynamics Observatory （SDO）, and the Reuven Ramaty High Energy Solar Spectroscopic lmager （RHESS1）. Among these events, WL emission was detected by SDO/HMI in 13 flares, associated with HXR emission. To quantitatively describe the strength of WL emission, equivalent area （EA） is defined as the integrated contrast enhancement over the entire flaring area. Our results show that the EA is inversely proportional to the HXR power-law index, indicating that stronger WL emission tends to be associated with a larger population of high energy electrons. However, no obvious correlation is found between WL emission and flux of non-thermal electrons at 50 keV. For the other group of 13 flares without detectable WL emission, the HXR spectra are softer （larger power-law index） than those flares with WL emission, especially for the X-class flares in this group.展开更多
At present there are three kinds of explanations of the origin of solar white-lightflares. One view holds that the chromospheric condensation is responsible for thecontinuous emission of white-light flares, either bel...At present there are three kinds of explanations of the origin of solar white-lightflares. One view holds that the chromospheric condensation is responsible for thecontinuous emission of white-light flares, either belonging to type Ⅰ or type ⅡAnother interpretation snys that the non-thermal effects may increase the opacity ofthe upper photosphere and consequently the deeper layers can be heated radiatively.The still other view is that the strong chromospheric heating can radatively heat thetemperature minimum region and the upper photosphere. We examine each of thesemechanisms and point out that none of them may be considered to be quitesatisfactory in interpreting the continua of white-light flares. Then a possible outlet istentatively proposed, which may take into account both chromospheric condensationand non-thermal effects. A semiempirical model will be requlred to justify thissuggestion.展开更多
为研究四种干燥方式对云南白茶香气品质影响,采用顶空固相微萃取-气相色谱-质谱联用技术(Headspace Solid-Phase Micro Extraction and Gas Chromatography Mass Spectrometry,HS-SPME-GC/MS),结合相对香气活度值(relative odor activit...为研究四种干燥方式对云南白茶香气品质影响,采用顶空固相微萃取-气相色谱-质谱联用技术(Headspace Solid-Phase Micro Extraction and Gas Chromatography Mass Spectrometry,HS-SPME-GC/MS),结合相对香气活度值(relative odor activity value,ROAV)法分析阴干、阴晒结合、晒干、烘干云南白茶的挥发性成分。结果表明:共检测出91种有效香气成分,以醇类、烯烃类挥发性成分种类为主,芳樟醇、β-蒎烯、水杨酸甲酯、苯乙醇、α-石竹烯、苯乙醛相对含量较高,不同干燥方式下茶香螺烷、反式青叶醇、己醇、2,2,3-三甲基-环丁酮、1-辛烯-3-醇、3,5-辛二烯-2-酮、苯甲酸甲酯、(E)-2-辛烯醇、苯甲醇的相对含量存在明显差异。ROAV法分析结果显示:云南白茶的主要香气贡献挥发性成分有6种,分别是2-庚醇、1-辛烯-3-醇、芳樟醇、香叶醇、苯乙醛、β-蒎烯。综合评价结果可知:不同干燥方式影响云南白茶香气类型和品质,阴干白茶清香带毫香,加工时间较长。晒干与晒阴结合干燥白茶带有日晒味。烘干白茶显花香,加工周期较短且不易受环境影响。展开更多
基金supported by NSF grants AGS-1539791, AGS-1250374, AGS-1408703 and AGS-1348513
文摘White-light （WL） flares have been observed and studied for more than a century since their first discovery. However, some fundamental physics behind the brilliant emission remains highly controversial. One of the important facts in addressing the flare energetics is the spatio-temporal correlation between the WL emission and the hard X-ray （HXR） radiation, presumably suggesting that energetic electrons are the energy sources. In this study, we present a statistical analysis of 25 strong flares （〉M5） observed simultaneously by the Helioseismic and Magnetic Imager （HMI）, on board the Solar Dynamics Observatory （SDO）, and the Reuven Ramaty High Energy Solar Spectroscopic lmager （RHESS1）. Among these events, WL emission was detected by SDO/HMI in 13 flares, associated with HXR emission. To quantitatively describe the strength of WL emission, equivalent area （EA） is defined as the integrated contrast enhancement over the entire flaring area. Our results show that the EA is inversely proportional to the HXR power-law index, indicating that stronger WL emission tends to be associated with a larger population of high energy electrons. However, no obvious correlation is found between WL emission and flux of non-thermal electrons at 50 keV. For the other group of 13 flares without detectable WL emission, the HXR spectra are softer （larger power-law index） than those flares with WL emission, especially for the X-class flares in this group.
文摘At present there are three kinds of explanations of the origin of solar white-lightflares. One view holds that the chromospheric condensation is responsible for thecontinuous emission of white-light flares, either belonging to type Ⅰ or type ⅡAnother interpretation snys that the non-thermal effects may increase the opacity ofthe upper photosphere and consequently the deeper layers can be heated radiatively.The still other view is that the strong chromospheric heating can radatively heat thetemperature minimum region and the upper photosphere. We examine each of thesemechanisms and point out that none of them may be considered to be quitesatisfactory in interpreting the continua of white-light flares. Then a possible outlet istentatively proposed, which may take into account both chromospheric condensationand non-thermal effects. A semiempirical model will be requlred to justify thissuggestion.
文摘为研究四种干燥方式对云南白茶香气品质影响,采用顶空固相微萃取-气相色谱-质谱联用技术(Headspace Solid-Phase Micro Extraction and Gas Chromatography Mass Spectrometry,HS-SPME-GC/MS),结合相对香气活度值(relative odor activity value,ROAV)法分析阴干、阴晒结合、晒干、烘干云南白茶的挥发性成分。结果表明:共检测出91种有效香气成分,以醇类、烯烃类挥发性成分种类为主,芳樟醇、β-蒎烯、水杨酸甲酯、苯乙醇、α-石竹烯、苯乙醛相对含量较高,不同干燥方式下茶香螺烷、反式青叶醇、己醇、2,2,3-三甲基-环丁酮、1-辛烯-3-醇、3,5-辛二烯-2-酮、苯甲酸甲酯、(E)-2-辛烯醇、苯甲醇的相对含量存在明显差异。ROAV法分析结果显示:云南白茶的主要香气贡献挥发性成分有6种,分别是2-庚醇、1-辛烯-3-醇、芳樟醇、香叶醇、苯乙醛、β-蒎烯。综合评价结果可知:不同干燥方式影响云南白茶香气类型和品质,阴干白茶清香带毫香,加工时间较长。晒干与晒阴结合干燥白茶带有日晒味。烘干白茶显花香,加工周期较短且不易受环境影响。
