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激光诱导双原子分子荧光激发谱结构的分析方法 被引量:5
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作者 张瑾 李春燕 +2 位作者 季学韩 凤尔银 崔执凤 《安徽师范大学学报(自然科学版)》 CAS 2004年第2期154-157,共4页
本文从光谱基本理论出发,分析了双原子分子电子振转能级结构和电子振转光谱结构的规律,得到了分析激光诱导激发谱结构和由实验测定的光谱计算分子常数的方法.
关键词 双原子分子 能级结构 光谱结构分析 分子常数 激光诱导 荧光激发谱
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Offner成像光谱仪结构设计的可行性分析 被引量:1
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作者 董金鑫 郑志忠 修连存 《现代科学仪器》 2017年第4期61-65,共5页
针对Offner成像光谱仪同心系统三个离轴放置的反射镜组成的系统,从光学成像质量分析出发,分析三个镜面面型、几何尺寸误差以及安装位置误差范围。利用Patran和Nastran软件分析与建模,分析该系统的静力载荷及模态响应,同时利用热光... 针对Offner成像光谱仪同心系统三个离轴放置的反射镜组成的系统,从光学成像质量分析出发,分析三个镜面面型、几何尺寸误差以及安装位置误差范围。利用Patran和Nastran软件分析与建模,分析该系统的静力载荷及模态响应,同时利用热光学理论研究镜片支撑与结构方案,从而开展分设计系统的结构布局:支撑方案和结构形式,更科学的评估Offner成像光谱仪结构设计的合理性。 展开更多
关键词 光谱结构设计与分析 光学像质分析 Patran和Nastran运用
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邮票上的物理学史(67)——天体物理学:星云和星系
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作者 秦克诚 《大学物理》 北大核心 2004年第1期61-65,共5页
比恒星更高的天体层次是星系.我们怎么知道有星系这个层次存在呢?我们自己属于哪个星系?
关键词 邮票 物理学史 天体物理学 星云 星系 银河系 天文观测 旋涡星系 恒星 光谱结构分析
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基于物理意义的二维散点图类型划分与遥感蚀变信息提取 被引量:15
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作者 张远飞 袁继明 +2 位作者 杨自安 吕伟艳 张思颖 《国土资源遥感》 CSCD 北大核心 2013年第2期57-62,共6页
遥感图像的二维散点图是表达2个波段组合光谱空间结构信息的最佳图示方式,但以往的工作只是研究了光谱数据点阵空间的背景-异常子空间模型,遥感图像二维散点图的分布规律、形态规则、多层次聚类套叠等基本空间几何结构特征,基于2个波段... 遥感图像的二维散点图是表达2个波段组合光谱空间结构信息的最佳图示方式,但以往的工作只是研究了光谱数据点阵空间的背景-异常子空间模型,遥感图像二维散点图的分布规律、形态规则、多层次聚类套叠等基本空间几何结构特征,基于2个波段概率密度联合高斯分布模型估计二维散点图的椭圆几何参数,以及遥感图像背景、干扰与蚀变异常同二维散点图空间结构的关系等。该文进一步研究了基于物理意义的遥感图像二维散点图的类型划分问题,并通过实例分析阐述了不同类型的二维散点图在遥感蚀变信息提取中的应用,表明依据这样的类型划分不仅能够定位出相应遥感图像的背景、干扰与蚀变信息,而且可以为遥感蚀变信息提取方法的选择提供理论依据,具有较好的应用效果。 展开更多
关键词 遥感蚀变信息提取 二维散点图 光谱空间结构分析
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Study on the application of spectral fatigue analysis 被引量:7
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作者 LIU Xiang-chun FENG Guo-qing REN Hui-long 《Journal of Marine Science and Application》 2006年第2期42-46,共5页
Fatigue failure has long been an important issue for ships and offshore structures. Among the numerous methods for predicting fatigue life, the spectral method is accepted as the most reliable. Although the theory beh... Fatigue failure has long been an important issue for ships and offshore structures. Among the numerous methods for predicting fatigue life, the spectral method is accepted as the most reliable. Although the theory behind spectral analysis is straight-forward, the analysis itself is complicated and time-consuming because it is closely related to critical technical details such as the application of fatigue loading (wave pressures and the inertial forces due to cargoes), the extraction of the stress, and the calculation of stress RAO. Here, four key technical details-loading application, displacement boundary condition, the calculation of stress RAO, and the extraction of the fatigue stress-are discussed thoroughly. For each aspect, a resolution is presented based on the finite element pre-and post-processing software MSC/PATRAN or FE solver MSC/NASTRAN. The resolutions are effective and efficient, which can help engineers perform spectral fatigue analysis accurately and faster. 展开更多
关键词 spectral fatigue analysis load application BC stress RAO stress extraction
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Molecular Fundaments of Mechanical Properties of Spider Silk 被引量:1
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作者 潘志娟 刘敏 +2 位作者 李春萍 李栋高 盛家镛 《Journal of Donghua University(English Edition)》 EI CAS 2003年第4期87-90,共4页
Dragline,framework and cocoon silk fibers of Araneus Ventricosus were used for this study.To investigate the microstructure mechanisms of stress-strain behavior of spider silk,firstly,amino acid compositions were anal... Dragline,framework and cocoon silk fibers of Araneus Ventricosus were used for this study.To investigate the microstructure mechanisms of stress-strain behavior of spider silk,firstly,amino acid compositions were analyzed and molecular conformations and crystallinity were measured with Raman spectra and X-ray diffraction respectively.The results showed that there were more amino acids with large side groups and polar ones in spider silk than those of Bombyx silk,and the amino acid distribution varied with different spider silk.The molecular structures were mainly α-helix and β-sheet,and random coil and β-turn existed as well.The proportions and arrangement of these conformations of dragline silk were different from framework and cocoon silk fibers.Microstructure was one of important factors of excellent mechanical properties of spider silk.Crystallinity of spider silk was very low,which implied that the roles of crystal on spider silk were not as great as other protein fibers. 展开更多
关键词 spider silk Raman spectrum X-ray diffraction amino acid mechanical property
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Spectroscopic Analysis of Structural Transformation in Biodiesel Oxidation 被引量:4
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作者 Wu Jiang Chen Boshui +1 位作者 Fang Jianhua Wang Jiu 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2013年第3期28-32,共5页
The oxidation behavior of three biodiesels of different origins,viz.rapeseed oil derived biodiesel,soybean oil derived biodiesel and waste oil based biodiesel,were tested on an oxidation tester.The chemical compositio... The oxidation behavior of three biodiesels of different origins,viz.rapeseed oil derived biodiesel,soybean oil derived biodiesel and waste oil based biodiesel,were tested on an oxidation tester.The chemical compositions of the biodiesels were characterized by gas chromatography.Thereafter,the structural transformation of fatty acid methyl ester(FAME)of the biodiesels was analyzed by an infrared spectrometer and an ultraviolet absorption spectrometer.The results demonstrated that the oxidation behavior of biodiesels of different origins was closely related to the composition and distribution of FAMEs.Higher concentration of unsaturated FAME with multi-double bonds exhibited poorer oxidation resistance.Furthermore,cis-trans isomerization transformation occurred in the unsaturated FAME molecules and conjugated double-bond produced during the oxidation process of biodiesel.Greater cis-trans variations corresponded to deeper oxidation degree.The higher the content of unsaturated FAME with multi-double bonds in a biodiesel,the more the conjugated double bonds was formed. 展开更多
关键词 BIODIESEL OXIDATION structural transformation spectroscopic analysis
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Designing of Acousto-optic Spectrum Analyzer
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作者 WANGDan-zhi SHAODing-rong LIShu-jian 《Semiconductor Photonics and Technology》 CAS 2004年第4期237-239,共3页
The structure of the acousto-optic spectrum analyzer was investigated including the RF amplifying circuit, the optical structures and the postprocessing circuit, and the design idea of the module was applied to design... The structure of the acousto-optic spectrum analyzer was investigated including the RF amplifying circuit, the optical structures and the postprocessing circuit, and the design idea of the module was applied to design the spectrum analyzer. The modularization spectrum analyzer takes on the performance stabilization and higher reliability, and according to different demands, the different modules can be used. The spectrum analyzer had such performances as the detecting frequency precision of 1 MHz, the detecting frequency error of 0.58 MHz, detecting responsivity of 90 dBm and bandwidth of 50 MHz. 展开更多
关键词 Acousto-optic signal processing Spectrum analyzer Structures designing
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Conformations and Structures of Ethoxycarbonyl Isothiocyanate Revealed by Rotational Spectroscopy
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作者 Yugao Xu Wenqin Li +1 位作者 Jiaqi Zhang Gang Feng 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2022年第6期875-882,I0011-I0038,I0072,共37页
The ethoxycarbonyl isothiocyanate has been investigated by using supersonic jet Fourier transform microwave spectroscopy.Two sets of rotational spectra belonging to conformers TCC(with the backbone of C-C-O-C,C-O-C=O,... The ethoxycarbonyl isothiocyanate has been investigated by using supersonic jet Fourier transform microwave spectroscopy.Two sets of rotational spectra belonging to conformers TCC(with the backbone of C-C-O-C,C-O-C=O,and O-C(=O)-NCS being trans,cis,and cis arranged,respectively)and GCC(gauche,cis,and cis arrangement of the C-C-O-C,C-O-C=O,and O-C(=O)-NCS)have been measured and assigned.The measurements of13C,15N and34S mono-substituted species of the two conformers have also been performed.The comprehensive rotational spectroscopic investigations provide accurate values of rotational constants and14N quadrupole coupling constants,which lead to structural determinations of the two conformers of ethoxycarbonyl isothiocyanate.For conformer TCC,the values of Pcckeep constant upon isotopic substitution,indicating that the heavy atoms of TCC are effectively located in the ab plane. 展开更多
关键词 Microwave spectroscopy Interstellar molecule Ab initio calculation Structural analysis Supersonic expansion
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Analysis of the Secondary Structure of the Transmembrane Domain of SARS CoV E Protein Using FTIR Spectroscopy
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作者 Qasem Abu-Remeleh Abd-Alkareem Alsharif Mutaz Akkawi 《Journal of Chemistry and Chemical Engineering》 2010年第6期8-14,共7页
One of the major obstacles facing the field of structural biology in the post genomic era is the inherent difficulty of analyzing the structure of membrane proteins under native conditions. The method of choice for st... One of the major obstacles facing the field of structural biology in the post genomic era is the inherent difficulty of analyzing the structure of membrane proteins under native conditions. The method of choice for studying such proteins is FTIR spectroscopy. Following the outbreaking of the severe acute respiratory syndrome (SARS) virus, in 2003, extensive work has been directed at elucidating the structure of the E transmembrane proteins of the SARS coronavirus. In this study, the secondary structure of the transmembrane a-helical bundles was analysised using the biophysical method site specific infrared dichroism (SSID). Sixteen amino acids were isotopically labeled with (~3C=180) at different positions of the primary structure of the synthesized E protein CoV. The secondary structure was studied using Attenuated Total Internal Reflection (ATR) FTIR spectroscopy. Based on our findings, the presence of two possible H-bonding interactions between the carbonyl oxygen of two residues 26 and 31 (Phe and Leu) respectively with water molecules which may be trapped within the helix structure were postulatesed. These interactions may cause a change in this structure. 展开更多
关键词 SARS CoV a-helix SSID ATR- FTIR H-bonding interactions.
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Upconversion Luminescence of Er^3+ and Co-Doped Er^3+/Yb^3+ Novel Transparent Oxyfluoride Glasses and Glass Ceramics: Spectral and Structural Properties
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作者 Arzumanyan Grigory Vartic Victoria +6 位作者 Kuklin Alexander Soloviov Dmitry Rachkovskaya Galina Zacharevich Galina Trusova Ekaterina Skoptsov Nikolay Yumashev Konstantin 《Journal of Physical Science and Application》 2014年第3期150-158,共9页
Transparent oxyfluoride silicate precursor glasses and glass ceramics with the novel composition (1) SiO2-PbO-PbFE-Er2O3, (2) SiO2-GeOE-PbO-PbFE-Er2O3 (3) SiO2-Al2O3-Y2O3-Na2O-NaF-LiF-Er2O3-YbF3 doped with Er^3... Transparent oxyfluoride silicate precursor glasses and glass ceramics with the novel composition (1) SiO2-PbO-PbFE-Er2O3, (2) SiO2-GeOE-PbO-PbFE-Er2O3 (3) SiO2-Al2O3-Y2O3-Na2O-NaF-LiF-Er2O3-YbF3 doped with Er^3+ and co-doped with Er^3+/Yb^3+ ions were synthesized. X-ray diffraction analysis (XRD) and Er3+ absorption spectra revealed precipitation of PbF2 nanocrystals dispersed in the glassy matrix. Under 980 nm laser excitation, intense green, red and near IR bands of upconversion luminescence (UCL) were recorded both before and after heat treatment. In the glass ceramics the upconversion intensity increased significantly. To our knowledge, for the first time the composition of the glass ceramics characterized by the small-angle neutron scattering (SANS) showed the cluster organization of PbF2 nanocrystals. 展开更多
关键词 Visible to near-infrared upconversion rare-earth luminescence oxyfluoride glass ceramics small-angle neutron scattering.
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