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1.
为实现玻碳电极在电化学传感器领域的高灵敏度检测利用, 在pH=5.0的磷酸盐缓冲溶液中, 用恒电位法对玻碳电极进行电化学活化,考察pH值、富集电位及富集时间对Pb2+检测效果的影响, 并研究最佳实验条件下的活化电极对Pb2+的检测性能. 实验结果表明:该活化电极对Pb2+的电化学检测响应电流具有增强效果,并具有检测时间短、灵敏度高的特点;检测线性范围为1×10-10~ 5×10-6 mol/L,最低检出限和定量限分别为3×10-11 mol/L和1.0×10-10 mol/L. 该活化电极在自来水Pb2+的测定中具有较高回收率, 可用于实际水质检测.  相似文献   

2.
在pH 5.5的0.1mol/L(CH2)6N4-HCl底液中可获得铟(Ⅲ)-荧光镓体系灵敏的络合吸附波。测定铟的线性范围为1.0×10-7~1.0×10-5mol/L,检测限达8×10-8mol/L, 测得电活性络合物的组成为铟∶荧光镓=1∶2,条件形成常数β=3.6×1013,表面电极反应速率常数ks1ks2ks3分别为4.4、1.74、10.8s-1,并研究了电极反应机理。  相似文献   

3.
为了实现快速测定样品中磺胺胍含量并降低检测成本,联合流动注射技术,建立了一种测定磺胺胍含量的新方法。基于在酸性条件下磺胺胍对高锰酸钾-甲醛体系的发光信号有明显的增强作用而建立了磺胺胍的检测体系并优化了各项参数。结果显示:在优化条件后,磺胺胍的线性范围为5×10-5~6×10-4 mol·L-1;对浓度为2×10-4 mol·L-1的磺胺胍溶液进行11次平行测定,计算出检出限为6×10-7 mol·L-1,检测结果的相对标准偏差为1.1%;加标回收实验测得的回收率为97%~103%。该方法检测快速、灵敏度高且成本较低,可成功应用于样品中磺胺胍的测定。  相似文献   

4.
用优化的Turkevich方法制备直径为50~60 nm的金纳米颗粒,  并通过表面增强Raman散射技术检测浓度为10-3~10-5 mol/L的痕量沙丁胺醇分子. 结果表明: 最低检出限为5×10-5 mol/L, 在100~750  μmol/L范围内, Raman光谱强度与浓度具有较好的线性关系, 相关系数R2=0.996 57, 但在更宽泛的浓度范围内不满足线性关系;  基于金纳米颗粒表面增强Raman散射光谱方法可实时、 快速检测痕量沙丁胺醇分子.  相似文献   

5.
山梨酸钾属于酸性食品防腐剂,能有效地抑制霉菌、酵母菌和好氧性细菌的活性,延长食品的保存时间,并保持食品原有的风味.本研究通过一步水热法合成了水溶性良好的荧光氮掺杂碳量子点(NCQDs),基于山梨酸钾能有效地猝灭NCQDs而构建了快速检测山梨酸钾的荧光探针.在最佳实验条件下,山梨酸钾浓度在3.0×10-5~1.0×10-4mol/L和1.0×10-7~3.0×10-5mol/L范围内与NCQDs荧光猝灭强度呈现良好的线性关系,检出限为9.5×10-8mol/L.我们已将其用于苏打水及白醋中山梨酸钾含量的测定,回收率分别为98.25%~102.7%和98.33%~101.8%.  相似文献   

6.
在碱性条件下, 在含有苯酚和盐酸羟胺的溶液中加入硝普钠, 有蓝色物质生成, 该物质在波长690 nm处有最大吸收. 由此建立了测定硝普钠注射液中硝普钠含量的新的分光 光度分析法. 该方法线性范围1.0×10-5~8.0×10-5 mol/L, 标 准溶液测定的相对标准偏差为0.57%(n=6), 实际样品测定的回收率>95%, 与标准方法 对照分析的相对误差为-1.2%~0.91% , 40倍的Cl-, SO2-4 , HCO, Mg2+和Ca2+不干扰 测定.  相似文献   

7.
将吸附修饰剂茜素红S(Sodium Alizarinsulfonate)的活性炭粉掺入碳糊中制成修饰碳糊电极, 以应用于铜离子的阳极溶出法测定, 响应电流与铜离子的浓度在 1×10-8~3×10-3 mol/L范围内呈良好的分段线性关系, 最低检出限为5.6×10-9 mol/L. 多数离子不干扰. 我们改进了传统修饰碳糊电极的做法, 不仅保留了其原有的传统优点, 而且活性炭的加入使电流有所提高, 电极修饰剂稳定.  相似文献   

8.
建立了基于聚溴甲酚紫修饰丝网印刷电极的循环伏安法检测水体中Pb2+的方法,讨论了影响Pb2+检测的因素,确立了最佳检测条件:富集时间为120 s、富集电压为-1.2 V,扫速为0.1 V·s-1。Pb2+在BCP/SPE电极上在1.0×10-7至1.1×10-4 g·L-1范围内呈线性关系,线性方程为,I(μA)=0.786c(μg·L-1)+5.794,R2=0.9984,检出限为1×10-8g·L-1。用加标法对四种水样中的Pb2+进行了检测,四种样品回收率在91%-110%之间,平均回收率为100.25%。  相似文献   

9.
以吡咯和邻苯二胺为功能单体,以盐酸环丙沙星为模板,在纳米金和还原氧化石墨烯(AuNP/rGO)修饰的玻碳电极上,采用电化学方法制备分子印迹聚合物薄膜电化学传感器.利用扫描电镜对修饰电极表面形貌进行表征;电化学技术测试分子印迹传感器性能.研究了纳米金和还原氧化石墨烯用量对电极电化学性能的影响,并对传感器制备和测试条件进行了优化.在优化条件下,分子印迹传感器对盐酸环丙沙星具有宽的线性检测范围(1.0×10-8~1.0×10-2 mol/L),低检测限(7.41×10-12 mol/L(S/N=3)),选择性高,稳定性好.此外,该传感器成功检测出了实际药品和牛奶样品中的盐酸环丙沙星.  相似文献   

10.
钛(Ⅳ)-槲皮素-氯酸盐体系极谱催化波的研究   总被引:1,自引:0,他引:1  
在pH3.2氯乙酸盐缓冲底液中,用单扫极谱法可获得灵敏的钛(Ⅳ)-槲皮素-氯酸盐催化波,其二阶导数检测限达7.0×10-9mol/L。已成功地应用于纯金属镁中10-4%钛的测定,并测得电活性络合物的组成为Ti(Ⅳ)∶槲皮素=1∶1,平行催化反应的速率常数k=4.8×105(mol/L)-1·s-1。  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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