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1.
高镁低钙样品中钙镁的直接配位滴定研究   总被引:1,自引:0,他引:1  
本文研究了以酒石酸盐-三乙醇胺-乙酰丙酮为联合掩蔽剂,用偶氮氯膦Ⅲ为指示剂,  相似文献   

2.
探讨了用甲醛作掩蔽剂磺量法测定啤酒中残留的二氧化硫,最佳分析条件:pH为3-4,甲醛用量为SO2含量的2-4倍,掩蔽时间为4min,温度25-33℃,该法的检出限为2^10^-5g/kg,可满足啤酒中二氧化硫的测定。  相似文献   

3.
用碘量法测定Fe^3+/Fe^2+体系中的游离酸   总被引:1,自引:0,他引:1  
提出了一种滴定强酸性含Fe^3+及Fe^2+体系中游离酸(其游离酸浓度〉1mol/L)的新方法。实验证明,将K2C2O4作为掩蔽剂时,利用过量的KIO3与过量的Na2S2O3在酸性溶液中的氧化还原反应可以测定体系中的游离酸,当体系中存在的Fe^2+时,可利用KMnO4(在强酸性下)或H2O2(在弱酸性下)的预氧化来消除Fe^2+的干扰。在加入过量的K2C2O4(C2O^2-4与Fe^3+的摩尔比值  相似文献   

4.
吸光光度法测定辣椒中的稀土总量   总被引:4,自引:1,他引:3  
研究了以对马脲酸偶氮氯膦为显色剂,测定辣椒样品中的稀土总量,选择三乙醇胺为掩蔽剂,体系酸度为0 .2 ~0 .24 mol·L- 1 ,该体系稀土离子含量在0 ~8 μg/25mL范围内服从比尔定律.用该法测定辣椒中的稀土总量,获得满意结果.测定的相对标准偏差≤3.1% ,方法回收率为95% ~101 % .  相似文献   

5.
提出了一种滴定强酸性含Fe3+及Fe2+体系中游离酸(其游离酸浓度>1mol/L)的新方法。实验证明,将K2C2O4作为掩蔽剂时,利用过量的KIO3与过量的Na2S2O3在酸性溶液中的氧化还原反应可以测定体系中的游离酸。当体系中存在Fe2+时,可利用KMnO4(在强酸性下)或H2O2(在弱酸性下)的预氧化来消除Fe2+的干扰。在加入过量的K2C2O4(C2O42-与Fe3+的摩尔比值为30)和过量的KIO3及Na2S2O3的条件下,其化学反应可以在30min内完成。采用I2回滴法测定游离酸,测试结果的精密度高,测定结果的相对偏差小于3%  相似文献   

6.
谢晓岚  焦志敏  马小雅  马延景 《科技信息》2013,(15):403-403,480
本文提出了简便、快速的岩矿中磷、砷联测方法。采用硫代硫酸钠还原掩蔽正砷酸,铋钼蓝分光光度法联合测定岩矿中磷、砷量,该方法准确高,重现性好。  相似文献   

7.
从生产工艺质量稳定性以及掩蔽能力对比研究了14个厂家包括酒石酸钾钠掩蔽剂在内的5种化合物,指出酒石酸钾钠生产工艺存在质量不稳定风险,不宜作为国标纳氏试剂分光光度法测定水中氨氮的掩蔽剂,EDTA四钠导致纳氏试剂不显色也不宜作为掩蔽剂使用,其余3种化合物综合掩蔽性能优于酒石酸钾钠,宜作为国标测定方法的掩蔽剂.  相似文献   

8.
本文研究了离子吸附型稀土矿浸出母液中,稀土总量的EDTA快速络合滴定法。提出了以10%磺基水杨酸2.0ml——乙酰丙酮1.0ml的联合掩蔽剂,作为Al~(3+)的掩蔽剂,以二甲酚橙为指示剂,用EDTA标准溶液滴定。这种双掩蔽剂能有效地掩蔽含量高达59mg的铝离子(Al_2O_3)对稀土元素络合滴定的干扰。  相似文献   

9.
本文研究了谷氨酸N—二硫代甲酸钠(铵)盐(GDTC)的合成、分析化学性能、某些络合物稳定常数的测定及其在络合滴定中的应用。实验指出,该试剂在同有关金属离子所成络合物的水溶性、稳定性及试剂的掩蔽量等方面均优于迄今已提出的同类氨荒酸,可以作为一种新的络合滴定掩蔽剂。  相似文献   

10.
应用偶氮氯膦-mk为显色剂,在HClO4介质中,以H3PO4-H2C2O4作掩蔽剂,直接测定高铬铸铁中铈组稀土.结果表明,方法适用于高铬铸铁、球墨铸铁和低合金钢中铈组稀土元素的测定.  相似文献   

11.
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   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
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   

14.
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   

15.
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   

16.
17.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

18.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

19.
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   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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