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星系金属丰度的研究进展(Ⅱ):光度-金属丰度关系
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作者 梁艳春 HAMMER Francois +1 位作者 邓李才 赵刚 《天文学进展》 CSCD 北大核心 2007年第1期22-35,共14页
金属丰度与星系光度是星系的重要特征参量,研究它们之间的关系有助于理解星系中恒星质量与金属成分的累积过程。评述了星系的光度-金属丰度关系的最新研究进展,包括对近邻星系、中等红移星系(0.4<z<1)及高红移星系(z>2)的研... 金属丰度与星系光度是星系的重要特征参量,研究它们之间的关系有助于理解星系中恒星质量与金属成分的累积过程。评述了星系的光度-金属丰度关系的最新研究进展,包括对近邻星系、中等红移星系(0.4<z<1)及高红移星系(z>2)的研究结果.由于观测样本跨越较宽的宇宙学时标,可以由此来探讨这一关系的演化过程,从而帮助理解星系演化的整体图景。 展开更多
关键词 天体物理学 星系 综述 金属丰度 光度-金属丰度关系
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Fermi伽马射线暴的光谱能量关系
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作者 骆娟娟 米立功 《贵州大学学报(自然科学版)》 2019年第5期38-42,共5页
基于Fermi卫星对伽马射线暴峰值能量探测灵敏度的提高,本文收集了Fermi卫星近8年的已知红移和Epeak的84个数据样本,再次分析Amati和Yonetoku关系。研究结果表明:Amati和Yonetoku关系可以分别用两条很好的直线拟合,对能量和光度关系进行... 基于Fermi卫星对伽马射线暴峰值能量探测灵敏度的提高,本文收集了Fermi卫星近8年的已知红移和Epeak的84个数据样本,再次分析Amati和Yonetoku关系。研究结果表明:Amati和Yonetoku关系可以分别用两条很好的直线拟合,对能量和光度关系进行了更新。大多数伽马射线暴的均质能量满足2.02×10^54erg量级,均质光度满足2.32×10^52erg量级。 展开更多
关键词 伽马射线暴 Fermi卫星 能量关系 光度关系
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长周期变星的演化及振动
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作者 郭建恒 《云南天文台台刊》 CSCD 北大核心 2002年第1期76-77,共2页
长周期变星的演化和振动一直是引人入胜的课题。这不仅仅是因为在它们的变化过程中有丰富的物理内容 ,更重要的是可以用它们来做河外星系距离的定标者。在本文中详细的计算了在z=0 .0 0 0 5,z=0 .0 0 1 ,z=0 .0 0 5,z =0 .0 1和z=0 .0 ... 长周期变星的演化和振动一直是引人入胜的课题。这不仅仅是因为在它们的变化过程中有丰富的物理内容 ,更重要的是可以用它们来做河外星系距离的定标者。在本文中详细的计算了在z=0 .0 0 0 5,z=0 .0 0 1 ,z=0 .0 0 5,z =0 .0 1和z=0 .0 2这样一个大的金属丰度跨度下 ,质量为 1 5M⊙ ,2 0M⊙ 和 3 0M⊙ 恒星的演化和振动。在计算中采用了最新的不透明度 ,考虑了星风损失对大质量星的影响 ,对于每一个模型都从零年龄主序演化到了中心氦燃烧结束。在文中仔细研讨了混合长参数以及中心对流核的对流超射对演化模型的影响 ,同时在中心氦燃烧阶段蓝超巨星和红超巨星的比值被用来限定模型的参数 (尤其是混合长和对流超射 )。尽管在文中并没有得到和观测一致的结论 ,即随着金属丰度的增加B/R增加。但是 ,通过在低金属丰度区采用对流超射 ,而在高金属丰度区放弃对流超射这一方法得到了与观测更相符合的比值。在新的演化模型的基础上 ,对于大质量星的振动进行了详细的计算。各项振动的性质用来和LMC ,M3 3以及MW中的RSGs做比较。对于LMC和M3 3中长周期变星 ,理论的周光关系和观测在基频振动模式下很好的符合 ;而对于MW中长周期变星 ,它们更可能在一阶模式下振动。最终 ,得到了金属丰度和周光关系的之间的联系 ,即随? 展开更多
关键词 大质量星 金属丰度 周期光度关系 长周期变星 振动
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Electronic Structures, DNA-binding, SAR, and Spectral Properties of Ruthenium Methylimidazole Complexes [Ru(MeIm)4L]^2+(L=iip,tip,2ntz) 被引量:1
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作者 李国栋 陈兰美 +3 位作者 王忻宇 巫玲凤 揭新明 陈锦灿 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2014年第2期159-167,I0003,共10页
Theoretical studies on the electronic and geometric structures, the trend in DNA-binding affinities as well as the the structure-activity relationship (SAR) of a series of water-soluble Ru(II) methylimidazole comp... Theoretical studies on the electronic and geometric structures, the trend in DNA-binding affinities as well as the the structure-activity relationship (SAR) of a series of water-soluble Ru(II) methylimidazole complexes, i.e. [Ru(Mehn)4iip]^2+ (1) (MeIm=l-methylimidazole, iip=2-(1H-imidazo-4-group)-lH-imidazo[n,5-f][1,10]phenanthroline), [Ru(MeIm)4tip]^2+ (2) (tip=2-(thiophene-2-group)-lH-imidazo[4,5-f] [i,10]phenanthroline), and [Ru(Melm)42ntz]^2+ (3) (2ntz=2-(2-nitro-l,3-thiazole-5-group)-lH-imidazo[4,5-f][1,10]phenanthroline), were car- ried out using the density functional theory (DFT). The electronic structures of these Ru(II) complexes were analyzed on the basis of their geometric structures optimized in aqueous solution, and the trend in the DNA-binding constants (Kb) was reasonably explained. The results show that the replacement of imidazole ligand by thiophene ligand can effectively improve the DNA-binding affinity of the complex. Meanwhile, it was found that introduc- ing the stronger electronegative N atom and NO2 group on terminal loop of intercalative ligand can obviously reduce the complex's LUMO and HOMO-LUMO gap energies. Based on these findings, the designed complex [Ru(MeIm)42ntz]^2+ (3) can be expected to have the greatest Kb value in complexes 1-3. In addition, the structure-activity relationships and antitumor mechanism were also carefully discussed, and the antimetastatic activity of the designed complex 3 was predicted. Finally, the electronic absorption spectra of this series of complexes in aqueous solution were calculated, simulated and assigned using DFT/TDDFT methods as well as conductor-like polarizable continuum model (CPCM), and were in good agreement with the experimental results. 展开更多
关键词 Ruthenium methylimidazole complex DNA-BINDING Structure-activity rela- tionships Spectral property DFT calculation
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Relationships Between Average Molecular Mass and Intrinsic viscosity of Three Typical Polyanhydrides
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作者 帅心涛 谭惠民 王晓青 《Journal of Beijing Institute of Technology》 EI CAS 1998年第1期39-42,共4页
Aim To study the relationships between average molecular mass and intrinsic viscosity of polyanhydrides. Methods With chloroform as solvent and petroleum ether as the precipitating agent polyanhydride was separated in... Aim To study the relationships between average molecular mass and intrinsic viscosity of polyanhydrides. Methods With chloroform as solvent and petroleum ether as the precipitating agent polyanhydride was separated into a series of grades with different average molecular mass. The absolute average molecular mass (M) and intrinsic viscosity ([]) of every grade were measured. Results and Conclusion The relationships between [] and M of three typical polyanhydrides were obtained from bi-logarithm coordinate plotting of [] versus M. 展开更多
关键词 polanhydrides []-M relationship light scattering intrinsic viscosity
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Application of Ray Scanning Method in Color Measurement
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作者 BIAN Xing-zhong CHEN Bing-ruo GONG Hong-mei 《Semiconductor Photonics and Technology》 CAS 2006年第1期54-57,共4页
A new method based on the traditional method of ray scanning has been introduced to resolve the problem of judging the color in the chromaticity diagram by employing the line segments approximate curve—— using polyg... A new method based on the traditional method of ray scanning has been introduced to resolve the problem of judging the color in the chromaticity diagram by employing the line segments approximate curve—— using polygonal approximate closed curve. Then a vector coordinate could be used to describe the curve instead of curve equations. So it is easy to judge the topology relation between an area and a point or a locus. And any data processing method has been used to save memory, which makes the improved ray scanning method is quite useful in the measurement of color. 展开更多
关键词 Vector data Raster data Topology relation Chromaticity diagram
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Organic single-crystal phototransistor with unique wavelength-detection characteristics 被引量:4
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作者 Mengxiao Hu Jinyu Liu +6 位作者 Qiang Zhao Dan Liu Qing Zhang Ke Zhou Jie Li Huanli Dong Wenping Hu 《Science China Materials》 SCIE EI CSCD 2019年第5期729-735,共7页
Organic phototransistors based on high-quality 2,8-dichloro-5,11-dihexyl-indolo[3,2-b]carbazo(CHICZ)single crystals show the highest photoresponsivity of 3×10^3 A W^-1, photosensitivity of 2×10^4 and the det... Organic phototransistors based on high-quality 2,8-dichloro-5,11-dihexyl-indolo[3,2-b]carbazo(CHICZ)single crystals show the highest photoresponsivity of 3×10^3 A W^-1, photosensitivity of 2×10^4 and the detectivity can achieve 8.4×10^14 Jones. We also discovered good linear dependence of log(photosensitivity) versus the wavelength when the devices were illuminated with a series of sameintensity but different-wavelength lights. The organic phototransistors based on CHICZ single crystal have potential applications in wavelength-detection. 展开更多
关键词 organic phototransistor single crystal photoresponsivity PHOTOSENSITIVITY wavelength-detection
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