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1.
光度分析法测定微量铜的方法较多。早在1952年就有人报导:由于2.9—二甲基—1.10—邻二氮杂菲结构的位阻效应,与铜(Ⅰ)具有特效性反应,成为测定微量铜的高选择性方法。但由于灵敏度不高(ε_(460)=7.9×10~3),使其应用受到限制。近些年来,在保持此法高选择性基础上进一步提高其灵敏度的工作有很大进展。我们采用铜-2.9—二甲基—1.10—邻二氮杂菲-荧光桃红缔合型三元络合物测定合金中的微量铜,灵敏度有很大提高(7.4×10~4),而且方法简便、快速、准确,使此法在实际应用中兼有高灵敏、高选择性的特点。  相似文献   

2.
研究了2-(2′-喹啉偶氮)-4,5-二甲基苯酚(QADMP)与铜(Ⅱ)的显色反应,在pH=4.0的HAc-NaAc缓冲介质中,CTMAB存在下,QADMP与铜(Ⅱ)生成分子比为2∶1的稳定红色配合物,该配合物λm ax=561 nm,摩尔吸光系数ε为4.56×104L.mol-1.cm-1,铜(Ⅱ)含量在0~10μg/25mL内符合比尔定律,新方法用于水样中微量铜的测定,结果满意.  相似文献   

3.
2-(2’-喹啉偶氮)-4,5-二甲基苯酚光度法测定水中的铜   总被引:3,自引:0,他引:3  
研究了2-(2′-喹啉偶氮)-4,5-二甲基苯酚(QADMP)与铜(Ⅱ)的显色反应,在pH=4.0的HAc-NaAc缓冲介质中,CTMAB存在下,QADMP与铜(Ⅱ)生成分子比为2∶1的稳定红色配合物,该配合物λm ax=561 nm,摩尔吸光系数ε为4.56×104L.mol-1.cm-1,铜(Ⅱ)含量在0~10μg/25mL内符合比尔定律,新方法用于水样中微量铜的测定,结果满意.  相似文献   

4.
本文研究了Cu(Ⅱ)与乙二醛双缩(1,8-氨基荼酚-3,6-二磺酸)的显色反应。测定Cu(Ⅱ)与该试剂形成1:1和1:2两种配合物;最大吸收峰在600nm,摩尔吸光系数为9.85×10~3l·mol~(-1)·cm~(-1),logβ_1=5.32,logβ_2=15.54,并用该法测定了铜镍矿和鄂铜矿中的微量铜。  相似文献   

5.
研究了显色剂2-[2’-(5-硝基一吡啶)-偶氮]-1,8一二羟基萘-3,6-二磺酸(简称为5-NO2-PACA)光度法测定微量镍的方法。在pH=11.5的NH3-NH4C1的缓冲介质中Ni^2+与5-N02-PACA在室温下很快形成1:1的蓝色配合物,最大吸收波长为635nm,表观摩尔吸光系数ε=1.00×10^5L·mol^-1·cm^-1,Ni^2+浓度在0—20μg/25mL范围内符合朗伯一比尔定律,该方法用于测定蔬菜(黄瓜、青椒)中微量镍,结果满意。  相似文献   

6.
研究了2-(4-氯-2-膦酸基苯偶氮)-7-(2,4-二氯苯偶氮)-1,8-二羟基-3,6-萘二磺酸(DC-CPA)与铋的显色反应.在0.06 mol/L HNO3介质中,铋与显色剂生成1∶2的蓝色配合物,最大吸收波长在691 nm处,该反应灵敏度高,6ε91=1.1×105L.mol-1.cm-1,B i(Ⅲ)含量在0.02~1.4 mg/L范围内符合比耳定律.应用该法测定了铜合金中微量铋,方法简便易行,结果满意.  相似文献   

7.
合成了新显色剂3-[ 苯并噻唑偶氮]-5-溴-2,6-二羟基苯甲酸, 用其与Cu2+显色反应, 在0.1 %溴代十六烷基吡啶 (CPB)水溶液存在下, Cu2+与显色剂在pH=6.98的缓冲溶液中形成稳定的1 ∶2的红色配合物. 其最大的吸收波长为533.0 nm, 表观摩尔吸光系数为3.64×104 L·mol -1·cm-1, 灵敏度较高 , 选择性较好. Cu2+含量在0.001 4~1.2 μg/mL服从比耳定律. 此显色反应应用于铝合金和铜锰铸铁中微量Cu2+的测定, 结果令人满意.  相似文献   

8.
以2,5-二苯甲酰基-1,4-苯二胺为原料,分别经过2次无水体系中的重氮化、碘代反应,合成得到2,5-二苯甲酰基-1,4-二碘苯.通过熔点测定、元素分析、磁共振(NMR)及X线单晶衍射对产物进行了表征及晶体结构分析.分析结果表明该晶体属于正交晶系,Pbca空间群,a=10.980 (2)nm,b=15.866 (3)nm,c=21.110(4)nm,Dx=1.944g/cm3,Z =8,F(000)=2032,μ=3.43mm-1,最终偏差因子分别为R=0.0624,wR=0.1728.  相似文献   

9.
童岩  杨新玲 《河南科学》2003,21(6):717-718
用2 (6 甲基 2 苯并噻唑偶氮) 5 二甲氨基苯甲酸(MBTAMB)分光光度法测定微量锰。配合物的表观摩尔吸光系数为7.12×104L·mol-1·cm-1。配合物的最大吸收波长为684nm,Mn2+浓度在0-18μg/25mL范围内符合比尔定律。方法用于茶叶和食品中微量锰的测定,结果满意。  相似文献   

10.
在弱酸性(pH=6.0)介质和表面活性剂CTMAB存在的条件下,3,5-二溴-4-(2,4二羟基)苯偶氮苯基荧光酮与铬(VI)形成稳定的三元络合物,可用分光光度法测定微量铬(VI),其最大吸收波长λ为537 nm,表观摩尔吸光系数ε为2.33×105 L·mol-1·cm-1,铬(VI))在4~650 μg·L-1范围内符合比尔定律,用拟定方法测定电镀废水中总铬含量,结果较满意.  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.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
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   

15.
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   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
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   

20.
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   

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