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Software-aided efficient identification of the components of compound formulae and their metabolites in rats by UHPLC/IM-QTOF-MS and an in-house high-definition MS^(2) library: Sishen formula as a case
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作者 Lili Hong Wei Wang +9 位作者 Shiyu Wang Wandi Hu Yuyang Sha Xiaoyan Xu Xiaoying Wang Kefeng Li Hongda Wang Xiumei Gao De-an Guo Wenzhi Yang 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2024年第10期1484-1495,共12页
Identifying the compound formulae-related xenobiotics in bio-samples is full of challenges.Conventional strategies always exhibit the insufficiencies in overall coverage,analytical efficiency,and degree of automation,... Identifying the compound formulae-related xenobiotics in bio-samples is full of challenges.Conventional strategies always exhibit the insufficiencies in overall coverage,analytical efficiency,and degree of automation,and the results highly rely on the personal knowledge and experience.The goal of this work was to establish a software-aided approach,by integrating ultra-high performance liquid chromatography/ion-mobility quadrupole time-of-flight mass spectrometry(UHPLC/IM-QTOF-MS)and in-house high-definition MS^(2) library,to enhance the identification of prototypes and metabolites of the compound formulae in vivo,taking Sishen formula(SSF)as a template.Seven different MS2 acquisition methods were compared,which demonstrated the potency of a hybrid scan approach(namely high-definition data-independent/data-dependent acquisition(HDDIDDA))in the identification precision,MS1 coverage,and MS^(2) spectra quality.The HDDIDDA data for 55 reference compounds,four component drugs,and SSF,together with the rat bio-samples(e.g.,plasma,urine,feces,liver,and kidney),were acquired.Based on the UNIFI™platform(Waters),the efficient data processing workflows were established by combining mass defect filtering(MDF)-induced classification,diagnostic product ions(DPIs),and neutral loss filtering(NLF)-dominated structural confirmation.The high-definition MS^(2) spectral libraries,dubbed in vitro-SSF and in vivo-SSF,were elaborated,enabling the efficient and automatic identification of SSF-associated xenobiotics in diverse rat bio-samples.Consequently,118 prototypes and 206 metabolites of SSF were identified,with the identification rate reaching 80.51%and 79.61%,respectively.The metabolic pathways mainly involved the oxidation,reduction,hydrolysis,sulfation,methylation,demethylation,acetylation,glucuronidation,and the combined reactions.Conclusively,the proposed strategy can drive the identification of compound formulae-related xenobiotics in vivo in an intelligent manner. 展开更多
关键词 Ultra-high performance liquid chromatography/ion-mobility quadrupole time-of-flight mass spectrometry(UHPLC/IM-QTOF-MS) Hybrid scan High-definition MS^(2)spectral library Sishen formula
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HPLC-MS^2鉴定大青叶水提液中的5种化学成分 被引量:17
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作者 刘瑞 袁波 +3 位作者 刘志刚 李小芩 熊志立 李发美 《中药材》 CAS CSCD 北大核心 2005年第9期772-774,共3页
目的:鉴定大青叶水提液中的化学成分。方法:大青叶的水提液经HPLC分离后,收集各色谱峰的馏分进行二级质谱分析,并和胞苷、尿苷、鸟苷、黄嘌呤和次黄嘌呤对照品的水溶液进行比较。结果:大青叶水提液HPLC中的5个色谱峰分别与胞苷、尿苷、... 目的:鉴定大青叶水提液中的化学成分。方法:大青叶的水提液经HPLC分离后,收集各色谱峰的馏分进行二级质谱分析,并和胞苷、尿苷、鸟苷、黄嘌呤和次黄嘌呤对照品的水溶液进行比较。结果:大青叶水提液HPLC中的5个色谱峰分别与胞苷、尿苷、鸟苷、黄嘌呤和次黄嘌呤对照品的t_R和UV光谱一致,并具有相同的二级质谱碎片离子。结论:大青叶中含有胞苷、次黄嘌呤、尿苷、黄嘌呤和鸟苷等5种成分。 展开更多
关键词 大青叶 胞苷 尿苷 鸟苷 黄嘌呤 次黄嘌呤 HPLC—MS^2 HPLC分离 化学成分 水提液
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HPLC-MS^2法分析朝鲜淫羊藿中的化学成分 被引量:22
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作者 袁杰 龚又明 +1 位作者 鞠鹏 孔令义 《中草药》 CAS CSCD 北大核心 2004年第4期371-374,共4页
目的 研究朝鲜淫羊藿中的化学成分。方法 采用 Merck L i Chro CAR分析柱 ,乙腈 -水 -冰醋酸梯度洗脱 ,流速 :1m L/ min,检测波长 :2 70 nm,质谱记录总离子流图 (TIC)。结果 从朝鲜淫羊藿中鉴定出 9个化合物。结论HPL C- MS2 能快速... 目的 研究朝鲜淫羊藿中的化学成分。方法 采用 Merck L i Chro CAR分析柱 ,乙腈 -水 -冰醋酸梯度洗脱 ,流速 :1m L/ min,检测波长 :2 70 nm,质谱记录总离子流图 (TIC)。结果 从朝鲜淫羊藿中鉴定出 9个化合物。结论HPL C- MS2 能快速、准确的鉴定出天然产物中的化学成分。 展开更多
关键词 朝鲜淫羊藿 黄酮苷类化合物 HPLC—MS^2
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基于Sentinel-2多光谱遥感影像的小浪底水质反演 被引量:1
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作者 郭荣幸 王超梁 +1 位作者 陈济民 韩红印 《人民黄河》 CAS 北大核心 2024年第1期93-96,102,共5页
多光谱遥感技术可根据遥感波段信息反演水质参数,降低监测成本,提高监测速度和质量,为大范围水环境监测提供了一种新的方法。通过分析小浪底水库的Sentinel-2多光谱影像以及采样点实测水质数据,建立了最佳光谱波段的水质参数反演模型,... 多光谱遥感技术可根据遥感波段信息反演水质参数,降低监测成本,提高监测速度和质量,为大范围水环境监测提供了一种新的方法。通过分析小浪底水库的Sentinel-2多光谱影像以及采样点实测水质数据,建立了最佳光谱波段的水质参数反演模型,对小浪底水库的化学需氧量(COD)、总磷(TP)、总氮(TN)和氨氮(NH_3-N)进行了遥感反演,验证了反演模型的精确度和稳定性,并反演了各水质参数的空间分布规律。结果表明:在4种水质参数反演模型中,COD模型精确度和稳定性最高,其次是TP、TN,最低的是NH_3-N,水库出水口和部分边缘COD质量浓度较高,水库中心TN、TP和NH_3-N质量浓度高于边缘处。 展开更多
关键词 多光谱遥感 水质反演 Sentinel-2 反演模型 小浪底水库
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Er掺杂PbF_(2)晶体的局域团簇结构与光谱性能研究
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作者 李琳 张沛雄 +4 位作者 谭俊成 朱思祁 尹浩 李真 陈振强 《人工晶体学报》 CAS 北大核心 2024年第7期1112-1120,共9页
本文采用Bridgman法成功生长了一系列Er∶PbF_(2)晶体。利用基于密度泛函理论的第一性原理计算详细研究了Er^(3+)在PbF_(2)晶体中的团簇效应。首次获得了Er∶PbF_(2)晶体的上转换发光特性(发光强度、颜色变化)与团簇结构之间的关系。研... 本文采用Bridgman法成功生长了一系列Er∶PbF_(2)晶体。利用基于密度泛函理论的第一性原理计算详细研究了Er^(3+)在PbF_(2)晶体中的团簇效应。首次获得了Er∶PbF_(2)晶体的上转换发光特性(发光强度、颜色变化)与团簇结构之间的关系。研究发现,随着Er^(3+)浓度增加,团簇从单聚体向高阶构型演化,Er^(3+)离子之间的距离先减小后增大,这使得上转换发光中的红色发射强度先增大后减小,红绿发光比也在Er^(3+)浓度高于6.5%(摩尔分数)后逐渐减小,即发光颜色可以从红色调整为黄绿色。该研究证明了稀土离子团簇的结构演化可以调控Er∶PbF_(2)的光谱特性,为多色发光材料的设计提供一种新方法。 展开更多
关键词 Er∶PbF_(2)晶体 上转换发光 密度泛函理论 铒离子团簇 光谱性能
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Effect of Nano-anatase TiO_2 on Spectral Characterization of PhotosystemⅡParticles from Spinach 被引量:10
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作者 HONGFa-shui YANGPing +4 位作者 GAOFeng-qing LIUChao ZHENGLei YANGFan ZHOUJuan 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2005年第2期196-200,共5页
The photosystem Ⅱ(PSⅡ) particles were purified by means of nano-anatase TiO_2 treatment of spinach and studied by spectroscopy. The results show that the electron transport and the oxygen-evolving rate of PSⅡ are a... The photosystem Ⅱ(PSⅡ) particles were purified by means of nano-anatase TiO_2 treatment of spinach and studied by spectroscopy. The results show that the electron transport and the oxygen-evolving rate of PSⅡ are accelerated after it has been treated with nano-anatase TiO_2; the UV-Vis absorption spectrum of PSⅡ particles is increased; the red shift of fluorescence emission peak of PSⅡ is 2 nm; the peak intensity is decreased; the PSⅡ signal Ⅱs of low temperature electron paramagnetic resonanace(EPR) spectrum is intensified under light, and the PSⅡ circular dichroism(CD) spectrum is similar to that of control. It is suggested that nano-anatase TiO_2 might bind to the PSⅡ reaction center complex and intensify the function of the PSⅡ electron donor, however, nano-anatase TiO_2 treatment does not change the configuration of the PSⅡ reaction center complex. 展开更多
关键词 Nano-anatase TiO_2 SPINACH PhotosystemⅡ spectral characterization
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Spectral and laser properties of Yb and Ho co-doped(YLa)_2O_3 transparent ceramic 被引量:2
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作者 黄栋栋 杨秋红 +4 位作者 王永刚 张浩佳 陆神洲 邹育婉 魏志义 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第3期505-507,共3页
Highly transparent Yb,Ho doped(YLa)2O3 ceramic was fabricated by conventional ceramic processing with nanopowders.The absorption and emission spectra of the ceramic was investigated.The energy transfer mechanism bet... Highly transparent Yb,Ho doped(YLa)2O3 ceramic was fabricated by conventional ceramic processing with nanopowders.The absorption and emission spectra of the ceramic was investigated.The energy transfer mechanism between Yb3+ and Ho3+ was also discussed.The strong emission band around 2 μm indicated that the Yb-Ho:(Y 0.90 La 0.10)2O3 transparent ceramic is a promising gain medium for the generation of 2 μm laser emissions.The laser operation of Yb-Ho co-doped(YLa)2O3 ceramic at 2.1 μm is first reported. 展开更多
关键词 Yb-Ho doped(YLa)2O3 transparent ceramic spectral properties 2 μm laser
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Spectral Parameters of Nd^(3+) Ion in Nd^(3+):NaGd(MoO_4)_2 Crystal 被引量:1
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作者 李修芝 王国富 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2006年第4期392-394,共3页
The spectral parameters of Nd^3+ ions in Nd^3+-doped NaGd(MoO4)2 crystal have been investigated based on Judd-Ofelt theory and obtained as follows: The intensity parameters Ωeff are Ω2 = 24.77×10^20, Ω4 =... The spectral parameters of Nd^3+ ions in Nd^3+-doped NaGd(MoO4)2 crystal have been investigated based on Judd-Ofelt theory and obtained as follows: The intensity parameters Ωeff are Ω2 = 24.77×10^20, Ω4 = 7.31×10^-20 and Ω6 = 6.91×10^-20 cm^2. The radiative lifetime is 100 μs, and the quantum efficiency is 93.9%. The fluorescence branch ratios were calculated to be β1 = 0.441, β2 = 0.469,β3 = 0.086 and β4=0.004. 展开更多
关键词 spectral parameters Judd-Ofelt theory Nd^3+:NaGd(MoO4)2 solid-state laser materials
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基于Sentinel-2影像的黄河南岸典型改良示范区土壤含盐量反演模型 被引量:1
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作者 王宇璇 屈忠义 +3 位作者 白燕英 刘霞 刘全明 刘琦 《农业机械学报》 EI CAS CSCD 北大核心 2024年第4期290-299,439,共11页
土壤盐渍化严重制约农田土壤环境的循环发展,高效准确地监测土壤盐分动态变化对盐碱地改良利用具有重要意义。为及时、有效地监测盐渍化土壤含盐量,以内蒙古黄河南岸灌区的4个典型盐碱化耕地改良示范区为例,利用Sentinel-2多光谱遥感影... 土壤盐渍化严重制约农田土壤环境的循环发展,高效准确地监测土壤盐分动态变化对盐碱地改良利用具有重要意义。为及时、有效地监测盐渍化土壤含盐量,以内蒙古黄河南岸灌区的4个典型盐碱化耕地改良示范区为例,利用Sentinel-2多光谱遥感影像,同步采集示范区内表层土壤的含盐量数据,通过相关性分析筛选敏感光谱指标,基于偏最小二乘回归(PLSR)、逐步回归(SR)、岭回归(RR)3种简单机器学习模型和深度学习Transformer模型建模,最后进行精度评价并优选出最佳含盐量反演模型。结果表明:示范区土壤反射率的可见光、红边、近红外波段反射率均与土壤含盐量呈正相关,短波红外波段反射率与土壤含盐量呈负相关,引入光谱指数能够有效提升Sentinel-2遥感影像与示范区表层土壤含盐量的相关性(相关系数绝对值不小于0.32);对比不同模型发现深度学习Transformer模型优于简单机器学习模型,验证集决定系数R~2和均方根误差(RMSE)分别为0.546和2.687 g/kg;含盐量反演结果与实地结果相吻合,为更精准反演内蒙古黄河南岸灌区盐渍化程度提供了参考。 展开更多
关键词 土壤盐渍化 含盐量反演 遥感 Sentinel-2 光谱指数 Transformer
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Spectral Hole-Burning of Eu ^( 3+)∶Y_2SiO_5 Crystal at 579.62 nm 被引量:1
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作者 薛绍林 陈凌冰 +3 位作者 赵有源 李富铭 张守都 王浩炳 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第S1期23-25,共3页
By using an Ar+ ion laser, a tunable Rh 6G dye laser(Linewidth: 0.5 cm -1) and a Coherent 899-21 dye laser as light sources and using a monochromator and a phase-locking amplifier, the optical properties of Eu 3+∶Y_2... By using an Ar+ ion laser, a tunable Rh 6G dye laser(Linewidth: 0.5 cm -1) and a Coherent 899-21 dye laser as light sources and using a monochromator and a phase-locking amplifier, the optical properties of Eu 3+∶Y_2SiO_5 crystal were detected. Persistent spectral hole burning (PSHB) were also observed in 5D_0-7F_0 transition in the crystal at the temperature of 16 K. For 15 mW dye laser (Wavelength: 579.62 nm) burning the crystal for 0.1 s a spectral hole with about 80 MHz hole width were detected and the hole can been keep for longer than 10 h. 展开更多
关键词 Eu 3+ ion∶Y_2SiO_5 spectral hole burning (PSHB)
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Spectral Structures of Eu^(2+) in ABF_4 and A_2SiF_6 (A=Na,K,Rb,Cs)
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作者 石春山 满石清 孙家跃 《Journal of Rare Earths》 SCIE EI CAS CSCD 1991年第1期35-38,共4页
The phosphors of ABF_4:Eu^(2+)and A_2SiF_6:Eu^(2+)(A=Na,K,Rb,Cs)have been synthesized,and the crystallographic data obtained accord with ASTM.In these materials,the f→f sharp lines emissions of Eu^(2+) were observed.... The phosphors of ABF_4:Eu^(2+)and A_2SiF_6:Eu^(2+)(A=Na,K,Rb,Cs)have been synthesized,and the crystallographic data obtained accord with ASTM.In these materials,the f→f sharp lines emissions of Eu^(2+) were observed.The coordination numbers of Eu^(2+)in both NaBF_4 and Na_2SiF_6 hosts are less than 8. 展开更多
关键词 spectral structure of Eu^(2+) Nephelauxetic effect Complex fluoride Coordination number PHOSPHOR
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Spectral Parameters of Nd^(3+) Ion in Nd^(3+):KLu(WO_4)_2 Crystal
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作者 TANGLi-Yong WANGGuo-Fu 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2005年第4期383-386,共4页
The spectral parameters of Nd3+ ions in Nd3+:Klu(WO4)2 crystal were calculated based on Judd-Ofelt theory and obtained as follows: for the oscillator strengths ?λ: ?2 = 7.5029×10-20 cm2, ?4 = 7.1837×10-20... The spectral parameters of Nd3+ ions in Nd3+:Klu(WO4)2 crystal were calculated based on Judd-Ofelt theory and obtained as follows: for the oscillator strengths ?λ: ?2 = 7.5029×10-20 cm2, ?4 = 7.1837×10-20 cm2 and ?6 = 3.1189×10-20 cm2; the radiative lifetime is 123 μs; the quantum efficiency is equal to 64.55%; and β1 = 0.5498, β2 = 0.3943, β3 = 0.0551 and β4 = 0.0027 for the fluorescence branch ratios. 展开更多
关键词 spectral parameters Nd3+:KLu(WO4)2 crystal Judd-Ofelt theory
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Growth and Spectral Properties of Nd^(3+) Doped KLa(MoO_4)_2 Crystal
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作者 WANG Guo-Jian HAN Xiu-Mei +1 位作者 LONG Xi-Fa WANG Guo-Fu 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2006年第2期192-196,共5页
Nd^3+ doped KLa(MoO4)2 single crystal with the size up to Ф25 × 40 mm^3 was grown by the Czochralski technique. The absorption and luminescence spectra of trivalent neodymium in KLa(MoO4)2 crystal were inve... Nd^3+ doped KLa(MoO4)2 single crystal with the size up to Ф25 × 40 mm^3 was grown by the Czochralski technique. The absorption and luminescence spectra of trivalent neodymium in KLa(MoO4)2 crystal were investigated at room temperature. The absorption and emission cross 10-20 sections are 3.02 ×10^-20 cm^2 at 808 nm and 20.01 × 10^-2 cm^2 at 1061 nm, respectively. The fluorescence lifetime is 164μs at room temperature. 展开更多
关键词 Nd^3+ :KLa(MoO4)2 crystal crystal growth spectral properties
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Yb∶Lu_(2)O_(3)透明陶瓷的制备及激光性能研究
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作者 李晴 姜珍兴 +8 位作者 王莹 马杰 王俊 刘鹏 章健 范金太 于浩海 张怀金 唐定远 《人工晶体学报》 CAS 北大核心 2024年第11期1884-1891,共8页
稀土离子掺杂的倍半氧化物陶瓷材料具有高热导率、低声子能量、高激光损伤阈值等优势,在固体激光领域具有巨大的应用潜力。本文采用化学共沉淀法合成了高纯度、低团聚Yb∶Lu_(2)O_(3)陶瓷粉体,在氧气气氛下预烧后,结合热等静压(HIP)烧... 稀土离子掺杂的倍半氧化物陶瓷材料具有高热导率、低声子能量、高激光损伤阈值等优势,在固体激光领域具有巨大的应用潜力。本文采用化学共沉淀法合成了高纯度、低团聚Yb∶Lu_(2)O_(3)陶瓷粉体,在氧气气氛下预烧后,结合热等静压(HIP)烧结制备了具有高致密度、高透过率的5%(原子数分数)Yb∶Lu_(2)O_(3)透明陶瓷。陶瓷的平均晶粒尺寸小于1μm,在1100 nm波长处的透过率超过81%。在974 nm波长处吸收截面为~0.97×10^(-20)cm^(2),在1.08μm波长处的发射截面为~0.39×10^(-20)cm^(2)。采用976 nm半导体激光器泵浦Yb∶Lu_(2)O_(3)陶瓷,室温条件下实现了11.67 W的连续激光输出,对应的斜效率为55.3%,激光中心波长为1080.1 nm。 展开更多
关键词 Yb∶Lu_(2)O_(3) 倍半氧化物 透明陶瓷 光谱分析 激光性能
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Synthesis and Crystal Structure of a Ni(Ⅱ) Complex of 2'-[4-N,N'-(Dimethylaminobenzyl- idene)]-3,5-dihydroxybenzoylhydrazide and Its Spectral Properties
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作者 贾文平 杨健国 +1 位作者 李芳 潘富友 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2009年第12期1635-1639,共5页
A new nickel(II) complex [NiL2](DMF)4 (HL = 2'-[4-N,N'-(dimethylamino- benzylidene)]-3,5-dihydroxybenzoylhydrazide) has been synthesized and its structure was characterized by IR,UV-Vis,1H NMR and elemental ... A new nickel(II) complex [NiL2](DMF)4 (HL = 2'-[4-N,N'-(dimethylamino- benzylidene)]-3,5-dihydroxybenzoylhydrazide) has been synthesized and its structure was characterized by IR,UV-Vis,1H NMR and elemental analysis. The fluorescence emission mechanism of the complex was discussed by fluorimetric spectra. The single-crystal structure was determined by X-ray diffraction analysis. The crystal belongs to the triclinic system,space group P1 with a = 0.9918(4),b = 1.1297(4),c = 1.1331(4) nm,α = 76.860(7),β = 75.105(6),γ = 89.022(7)°,V = 1.1936(8) nm^3,Z = 1,μ = 0.472 mm^-1,Dc = 1.319 g/cm^3,F(000) = 502 and Rint = 0.0913. In the title compound,the nickel(II) atom is four-coordinated with two nitrogen atoms from amide and two oxygen atoms from keto group. The complex is centrosymmetric with nickel located at the center. 展开更多
关键词 nickel(II) complex 2'-[4-N N'-(dimethylaminobenzylidene)]-3 5-dihydroxyben- zoylhydrazide crystal structure spectral properties
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Crystal growth,spectral properties and Judd-Ofelt analysis of Pr:CaF_(2)-YF_(3)
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作者 Jie Tian Xiao Cao +7 位作者 Wudi Wang Jian Liu Jianshu Dong Donghua Hu Qingguo Wang Yanyan Xue Xiaodong Xu Jun Xu 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第10期624-629,共6页
The 0.6 at.%Pr^(3+)-doped CaF_(2)-YF_(3)crystal was successfully grown by the temperature gradient technique(TGT).X-ray diffraction analysis showed that the grown crystal still had cubic structure.The absorption spect... The 0.6 at.%Pr^(3+)-doped CaF_(2)-YF_(3)crystal was successfully grown by the temperature gradient technique(TGT).X-ray diffraction analysis showed that the grown crystal still had cubic structure.The absorption spectrum,emission spectrum,Judd-Ofelt analysis and fluorescence decay curve at room temperature were discussed.The fluorescence lifetime of Pr:CaF_(2)-YF_(3)crystal was 45.46µs,and theσem·τof ^(3)P0→^(3)H_(6) and ^(3)P0→^(3)F_(2) transitions were calculated to be 80.92×10^(−20) cm^(2)·µs and 388.7×10^(−20) cm^(2)·µs,respectively.The FWHMs are 20.1 nm and 6.8 nm,which are higher than those of Pr:LiYF_(4),Pr:LiLuF_(4),Pr:LiGdF_(4) and Pr:BaY_(2)F_(8) crystals.The results show that the Pr:CaF_(2)-YF_(3)crystal is expected to achieve 605 nm orange light and 642 nm red light laser operation. 展开更多
关键词 CaF2-YF3 crystal growth spectral property Judd-Ofelt theory
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基于WorldView-2高分影像信息增强及提取在卡而却卡地区遥感调查中的应用
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作者 魏本赞 张策 +2 位作者 张恩 卢辉雄 汪冰 《世界核地质科学》 CAS 2024年第5期1013-1022,共10页
为进一步探讨WorldView-2高分遥感数据在遥感调查中的应用效果,笔者选择青海卡而却卡地区进行图像信息增强及信息提取方法研究。在分析研究区内不同岩性的光谱曲线特征的基础上,针对遥感解译中目视解译效果不好、图像模糊和对比度不够... 为进一步探讨WorldView-2高分遥感数据在遥感调查中的应用效果,笔者选择青海卡而却卡地区进行图像信息增强及信息提取方法研究。在分析研究区内不同岩性的光谱曲线特征的基础上,针对遥感解译中目视解译效果不好、图像模糊和对比度不够等问题,提出一系列图像增强处理的方法,这些方法显著增强了岩性、构造的识别效果,可以更好地辅助高分遥感解译工作。同时,通过基于纹理和光谱信息的影像分类方法对大理岩、岩浆岩信息提取研究,可以较准确地圈定大理岩、岩浆岩岩性界线,并通过与现有地质矿产资料进行对比,该方法形成的岩性-构造解译图反映的岩性、构造等信息更加详细、丰富。 展开更多
关键词 WorldView-2数据 光谱特征 图像增强 信息提取 卡而却卡地区
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Persistent Spectral Hole Burning of Eu^3+ Doped Y2SiO5 Crystal at 579.62 nm
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作者 Xue Shaolin Chen Lingbing +3 位作者 Zhao Youyuan Li Fuming Zhang Shoudu Huang Haobing 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第4期433-433,共1页
By using an Ar^+ ion laser, a tunable Rh6G dye laser(linewidth: 0.5 cm^-1) pumped by the second harmonic of a YAG:Nd laser and an 899-21 dye laser as light sources and using a monochromator, a phase-locking ampli... By using an Ar^+ ion laser, a tunable Rh6G dye laser(linewidth: 0.5 cm^-1) pumped by the second harmonic of a YAG:Nd laser and an 899-21 dye laser as light sources and using a monochromator, a phase-locking amplifier and a computer as the data detecting system, the spectra and spectral hole burning of Eu^3+:Y2SiO5 crystal were researched in this paper.Photoluminescence excitation spectrum and site selective fluorescence spectrum were detected at room temperature and 77 K. Hole burning experiments were reached at 16 K. A spectral hole with hole width of about 80 MHz were detected and it could be kept for 10 h. 展开更多
关键词 Eu^3 :Y2SiO5 crystal SPECTRUM persistent spectral hole burning rare earths
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Spectral properties of LH2 exhibit very similar even when heterologously express LH2 with <i>β</i>-subunit fusion protein in <i>Rhodobacter</i><i>sphaeroides</i>
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作者 Zhiping Zhao Xin Nie +3 位作者 Zongli Hu Guoping Chen Zaixin Li Zhi Zhang 《Advances in Biological Chemistry》 2013年第1期101-107,共7页
Interactions between the light-harvesting subunits and the non-covalently bound photopigments attribute considerably to the spectral properties of photosynthetic bacteria light-harvesting complexes. In our previous st... Interactions between the light-harvesting subunits and the non-covalently bound photopigments attribute considerably to the spectral properties of photosynthetic bacteria light-harvesting complexes. In our previous studies, we have constructed a novel Rhodobacter sphaeroides expression system. In the present study, we focus on the spectral properties of LH2 when heterologously express LH2 with β-subunit- GFP fusion protein in Rb. sphaeroides. Near infra-red spectrum of LH2 remained nearly unchanged as measured by spectroscopy. Fluorescence spectrum suggested that the LH2 with β-subunit-GFP fusion protein complexes still possessed normal activity in energy transfer. However, photopigments contents were significantly decreased to a very low level in the LH2 with β-subunit-GFP fusion protein complexes compared to that of LH2. FT-IR spectra indicated that interactions between photopigments and LH2 α/β- subunits appeared not to be changed. It was concluded that the LH2 spectral properties exhibited very similar even when heterologously expressed LH2 b-subunit fusion protein in Rb. sphaeroides. Our present study may supply a new insight into better understand the interactions between light-harvesting subunits and photopigments and bacterial photosynthesis and promote the development of the novel Rb. sphaeroides expression system. 展开更多
关键词 LH2 spectral Property FT-IR Photopigment
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大气CO_(2)浓度升高背景下冬小麦冠层光谱特征和地上生物量估算
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作者 黄宏胜 张馨月 +1 位作者 居辉 韩雪 《作物学报》 CAS CSCD 北大核心 2024年第4期991-1003,共13页
本研究旨在探究大气CO_(2)浓度升高对冬小麦全生育时期冠层光谱特征的影响,并基于筛选的敏感波段建立地上生物量(AGB)与光谱参数的定量关系。为此,在2021—2022年的冬小麦生长季,利用开放式CO_(2)富集系统(Mini-FACE),设定大气CO_(2)浓... 本研究旨在探究大气CO_(2)浓度升高对冬小麦全生育时期冠层光谱特征的影响,并基于筛选的敏感波段建立地上生物量(AGB)与光谱参数的定量关系。为此,在2021—2022年的冬小麦生长季,利用开放式CO_(2)富集系统(Mini-FACE),设定大气CO_(2)浓度(ACO_(2),(420±20)μL L^(–1))和高CO_(2)浓度(ECO_(2),(550±20)μL L^(–1))两个处理水平,分析了高CO_(2)浓度下光谱特征变化,基于连续投影算法(SPA)、逐步多元线性回归(SMLR)和偏最小二乘法回归(PLSR)筛选AGB敏感波段并构建估算模型。结果表明:CO_(2)浓度升高使冬小麦拔节期和开花期AGB显著增加。红边和近红边反射率及红边面积在拔节期增加,在开花期和灌浆期降低,蓝边、黄边和红边位置在不同生育时期均发生移动;AGB的敏感光谱波段主要分布在红边和近红边区域,CO_(2)浓度升高缩小了AGB敏感波段范围,但不影响AGB的估算;AGB的SMLR和PLSR模型均取得了较高的估算精度(R^(2)>0.8),其中SMLR模型中的R_(799′)、D_(y)、SD_(y)和PRI等特征参数与AGB显著相关,R^(2)为0.866。PLSR模型(R^(2)>0.9)在估算精度和稳定性上优于SMLR模型。本研究可为未来高CO_(2)浓度下冬小麦生长发育的遥感监测提供理论基础和技术方法。 展开更多
关键词 CO_(2)浓度升高 冬小麦 地上生物量 冠层光谱特征 回归分析
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