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1.
本文研究了锰-1.10菲箩啉-荧光桃红萃取光度法测定锰的条件.在弱酸性及中性条件下锰(Ⅱ)与1.10-菲萝啉及荧光桃红形成可被氯仿萃取的[Mn(Phen)_2]Phlo络合物,最大吸收波长λ_(man)=562.8nm,s=1.073×10~6L mol~(-1)·cm~(-1),其含量在0~10μg/10ml氯仿呈线性关系.  相似文献   

2.
本文在聚乙烯醇和十二烷基磺酸钠存在下,Cd(Ⅱ)与碘化物和罗丹明B形成离子缔合物分光光度法测定微量镉,缔合物的最大吸收波长λ_(max)=600nm,表观摩尔吸光系数ε_(600)=6.18×10~5,Cd(Ⅱ)的浓度在0—0.08μg/ml遵守比耳定律,结合巯基棉富集,本方法用于水库水样测定微量镉,结果良好.  相似文献   

3.
合成了香草醛缩4-氨基安替比林希夫碱,通过红外光谱仪、核磁共振仪、元素分析仪和单晶X-衍射仪对产物的结构进行了表征,并对其与几种金属离子作用时的荧光性质进行了分析.结果表明,该希夫碱晶体属单斜晶系,空间群为C-2yc,晶胞参数a=1.179 3 nm,b=1.697 8 nm,c=0.878 0 nm,α=90.00°,β=99.69°,γ=90.00°,V=1.733 nm3,Z=4,D_c=1.262 g/cm3,Z=4,D_c=1.262 g/cm3,μ=0.088 mm3,μ=0.088 mm(-1),F(000)=693,ρ_(max)=173 e·nm(-1),F(000)=693,ρ_(max)=173 e·nm(-3),ρ_(min)=-213 e·nm(-3),ρ_(min)=-213 e·nm(-3).该希夫碱与金属离子作用后,在684 nm(λ_(max))处具有较强的荧光吸收,其中Cd(-3).该希夫碱与金属离子作用后,在684 nm(λ_(max))处具有较强的荧光吸收,其中Cd(2+)、Cu(2+)、Cu(2+)所产生的荧光增强效应显著.  相似文献   

4.
研究了Ag(I)-phen-TPPS_4荧光体系,建立了痕量银的荧光测定新方法。在碱性介质中,Ag(phen)_2~ 络阳离子与TPPS_4 的阴离子形成三元离子对缔合物(Ag:Phen:TPPS_4=1:2:1),导致TPPS_4 的荧光(λex=413 nm,λem=638 nm)猝灭而定量测定银。也可直接测定缔合物的荧光(λex=438 nm,λem=648 nm)而定量测定银。两种测定方法在Ag(I)浓度为0~3 μg/25 ml范周内,工作曲线呈良好线性关系,方法的检出限前者为0.88 PPb,后者为5.2 PPb。用于废水中微量银的测定,变异系数6%,标准加入量的回收率 92~107%。  相似文献   

5.
本文研究了铁 -5′-硝基水杨基荧光酮 ( 5′-NSAF) -溴化十六烷基三甲铵 ( CTMAB)体系的荧光特性 .实验结果表明 ,在 p H为 3.1~ 4 .7的 HAc-Na Ac缓冲介质中 ,体系的荧光熄灭程度最大且恒定 ,其最大激发波长λex=2 52 nm,发射波长λem=556nm .当含铁量在 0~ 2 .8μg/1 0 ml范围内 ,荧光熄灭程度与浓度呈线性关系 ,藉以测定微量铁 .方法简便、快速 ,并且稳定性高 ,用于食品中微量铁的测定 ,结果满意 .  相似文献   

6.
建立了双波长高效液相色谱-荧光检测器同时检测保健品中褪黑素和维生素B6含量的方法.考察了不同超声时间、清洗次数对保健品中褪黑素和维生素B6溶出量的影响,并对色谱条件进行了优化.采用Inertsil-100A C18色谱柱(4.6 mm×250 mm,5μm),以甲醇-水(65∶35,体积比)为流动相,流速1.0 mL/min,柱温25℃,进样量10μL.采用双波长法,0~4 min,λ_(ex)=332 nm,λ_(em)=397 nm;4 min后,λ_(ex)=286 nm,λ_(em)=352 nm.在优化的样品预处理条件、色谱条件下,维生素B6和褪黑素分别在0.1~100μg/L和1.0~1 000μg/L内线性关系良好(r≥0.998),最低检出限分别为3×10~(-3)μg/L和3×10~(-2)μg/L;定量限分别为1×10~(-2)μg/L和1×10~(-1)μg/L,平均回收率分别为99.07%和97.97%(n=3),相对标准偏差为0.04%~0.98%.本方法检测快速,灵敏,重现性较好,可用于保健品中褪黑素和维生素B6的同时测定以及市售保健品的质量控制.  相似文献   

7.
本文提出了用4.5-二溴苯基荧光酮-非离子表面活性剂荧光熄灭法测定微量钒的新方法,实验证明,最佳酸度为pH=5.20~5.95,激发波长E_x=363nm。发射波长E_M=568nm;钒含量在0.25~5.0μg/25ml范围内,荧光强度与浓度之间符合线性关系,方法灵敏度高,检出极限为1×10~(-2)μg/ml。此方法用于合金钢中微量钒的测定,获得满意的结果。  相似文献   

8.
本文研究了碱性染料水相光度法直接测定痕量锑的可能性.在高分子化合物聚乙烯醇存在下,锑(Ⅴ)—硫氰酸钾—孔雀绿形成水溶性离子缔合物,λ_(max)=610nm,ε_(610nm)=1.28×10~5.锑(Ⅴ)量在0~10μg/25ml范围内服从比尔定律.方法可用于纯铅中痕量锑的测定.  相似文献   

9.
研究了pH、防腐剂、氧化还原剂等因素对苋菜红荧光光谱的影响,建立了荧光光谱法检测食用合成色素苋菜红的分析方法。以pH=6的三酸缓冲溶液为研究体系,测定波长为λ_(ex)=350 nm,λ_(em)=421 nm,对金属离子、食用酸、猝灭剂、糖类、防腐剂等对苋菜红荧光光谱的影响做了实验研究,测定了模拟样品的加标回收率,建立了测定苋菜红的荧光分析方法,相关系数r=0.9947,检出限为1.00×10~(-7)mol/L,回收率在92.25%~102.1%。以硫酸奎宁为参比标准,测量了苋菜红在不同激发波长下的荧光量子产率,结果表明:在λ_(ex)=320 nm,荧光量子产率较大为0.336。  相似文献   

10.
本文提出了以 5-Br-PADAP 做显色剂,在乙醇存在下,在pH=3.4的KHC_8H_4O_4-HCl缓冲溶液内,选择波长对:526nm(λ_2)-646nm(λ_1)(测镍)、620nm(λ_2)-674nm(λ_1)(测钒),用双波长分光光度法同时测定原油及渣油中微量镍、钒的新方法。本法灵敏度高、重复性好。镍、钒服从比耳定律的线性范围均在0~22μg/25ml,回收率在90~119%。经对多种油样的多次测定表明:本法的标准偏差<1.8ppm,相对标准偏差<10%。本测定结果与原子吸收光谱法、等离子体直读光谱法等分析方法的测定结果相符合。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

13.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

14.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

15.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

16.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

17.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

18.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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