首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
共振光散射增强法测定痕量铅   总被引:6,自引:0,他引:6  
基于铅可以对十六烷基三甲基铵(CTMAB)-四磺基锰酞菁(MnTSPc)-DNA共振光散射(RLS)体系产生强烈的敏化作用,从而建立了测定痕量铅的灵敏的RLS新方法.该法的线性为0.0-4.0×10-6mol/L,检出限3δ)为8.56×10-8mol/L,对1.0×10-6mol/L的铅标准溶进行连续9次平等测定,相对标准偏差为1.6%.我们用该法对实际水样进行了分析测量,效果良好.  相似文献   

2.
本文以硝酸铈铵为引发剂,研究了丙烯酸丁酯与罗布麻纤维的接枝共聚反应规律及产物的物理性能。当铈离子浓度为6.5×10~(-3)~14×10~(-3)mol/L,单体浓度为0.7×10~(-1)~1.2×lO~(-1)mol/L,氢离子浓度为7×10~(-2)~1O×10~(-2)mol/L,40℃,反应3h,可以得到较高接枝率。接枝纤维断裂伸长比纯纤维有所提高,改善了柔顺性。  相似文献   

3.
采用循环伏安法分析了硼氢化钠(Na BH_4)在金(Au)电极上的电化学氧化还原行为,在-0.473 V电位处发现了比较明晰且稳定的BH_4~-特征氧化峰,可作为BH_4~-存在的定性判据。通过线性伏安扫描,对浓度为1.0×10~(-4)~9.0×10~(-3)mol/L的Na BH_4碱性溶液进行了测定,发现Na BH_4特征氧化峰的峰值电流与其浓度呈良好的线性关系,相关系数为0.998 4。利用线性伏安法分别对5.0×10~(-4)mol/L Na BH_4+0.10 mol/L Na OH溶液和5.0×10~(-3)mol/L Na BH_4+0.10 mol/L Na OH溶液平行测定5次,所得结果的平均相对误差分别为3.18%和1.63%,相对标准偏差分别为2.38%和1.88%。  相似文献   

4.
化学发光法测定水产品中链霉素残留   总被引:3,自引:0,他引:3  
建立了水产品中链霉素残留的化学发光检测方法,最佳条件为:样品用100 g/L三氯乙酸提取后,经C18固相萃取柱净化,以0.1 mol/L NaOH调pH,5×10-4mol/L鲁米诺,5×10-4mol/L高碘酸钾,1×10-9mol/L锰离子为发光体系进行测定,在0.1~5 mg/L范围内,链霉素浓度与发光强度呈现良好的线性关系(r2=0.998 3),以三倍信噪比计算,检出限为0.05μg/g。该方法适用于测定经过前处理的水产样品(虾、鲫鱼和牙鲆)中链霉素的残留,准确度及精密度符合检测要求。  相似文献   

5.
提出了Ru(phen) 3 2 + -SO3 2 --Ce(IV)体系化学发光法测定溶液中亚硫酸盐的方法 SO3 2 -浓度与化学发光强度在 1 0× 10 -7~ 1 0× 10 -4mol/L范围内成正比 ,检出限为 1 97× 10 -7mol/L(S/N =3) ,1 0× 10 -4mol/LSO3 2 -溶液重复 6次测定结果的相对标准偏差为 4 9% 该方法用于测定白葡萄酒中亚硫酸盐总含量为 4 0 0 6× 10 -5mol/L ,加标回收结果令人满意  相似文献   

6.
提出了Ru(phen)32+-SO32+-Ce(Ⅳ)体系化学发光法测定溶液中亚硫酸盐的方法.SO32-浓度与化学发光强度在1.0×10-7~1.0×10-4mol/L范围内成正比,检出限为1.97×10-7mol/L(S/N=3),1.0×10-4mol/LSO32溶液重复6次测定结果的相对标准偏差为4.9%.该方法用于测定白葡萄酒中亚硫酸盐总含量为4.006×10-5mol/L,加标回收结果令人满意.  相似文献   

7.
提出了吸附溶出催化伏安法测定痕量锗的方法。该方法最佳体系为0.15 mol/L KCl+1.0×10~(-3) mol/L 3,4-二羟基苯甲醛(DHB)+2.0×10~(-3)mol/L EDTA+3.0×10~(-3)mol/L V(Ⅳ),pH2.15。其线性范围为1.2×10~(-10)~6.O×10~(-8)mol/L,最低检出浓度为3.6×10~(-11)mol/L Ge(Ⅳ)。  相似文献   

8.
报道了在适量表面活性剂的存在下 ,钠型蒙脱石 (SWy - 2 )修饰碳糊电极高灵敏度测定环境体系中微量Cd2 + 的电化学方法 .该电极在HAc-NaAc (pH =5 .0 )溶液中 ,1.0× 10 -4mol/L的溴代十八烷基三甲基铵(STAB)存在下 ,用溶出伏安法测定Cd2 + ,在 - 0 .81V(vs ,SCE)处有灵敏的阳极溶出峰 ,且峰电流与Cd2 + 浓度在 2 .0× 10 -8~ 1.5× 10 -6mol/L的范围内 ,呈良好的线性关系 .该方法用于水样中镉的测定 ,检出限为 2 .0×10 -9mol/L .  相似文献   

9.
《咸宁学院学报》2002,22(6):66-68
提出了Ru(phen)32+-SO32+-Ce(Ⅳ)体系化学发光法测定溶液中亚硫酸盐的方法.SO32-浓度与化学发光强度在1.0×10-7~1.0×10-4mol/L范围内成正比,检出限为1.97×10-7mol/L(S/N=3),1.0×10-4mol/LSO32溶液重复6次测定结果的相对标准偏差为4.9%.该方法用于测定白葡萄酒中亚硫酸盐总含量为4.006×10-5mol/L,加标回收结果令人满意.  相似文献   

10.
在0.56mol/L NaAc—0.04%Tiron 溶液中,铅(Ⅱ)与 Tiron 产生的络合物,在单扫描示波仪上可观察到一灵敏的极谱导数波,其峰电位为-0.49V(vs.SCE),峰电流与铅浓度在7.7×10~(-6)—6.8×10~(-6)mol/L 范围内成线性关系,检测限为3.8×10~(-(?))mol/L.应用该波测定了铜合金中的微量铅,结果良好,精密度和准确度均较满意,本文研究了形成铅-Tiron 络合物吸附波的条件,探讨了波的性质,用极谱法测定出其络合比为1:1.  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.
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   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  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.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  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.
19.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

20.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号