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1.
采用N,N-二甲基甲酰胺分散碳纳米管(CNT),制备碳纳米管修饰玻碳电极.运用循环伏安法和Tafel曲线法,研究了糠醛在碳纳米管修饰玻碳电极上的电化学行为.实验结果表明:在浓度为0.1mol/L的磷酸盐缓冲溶液(pH6.8)中,碳纳米管修饰电极对糠醛具有良好的催化作用.在扫速为50-1000mV/s的范围内,糠醛的还原峰电流与扫速的平方根成良好的线性关系,表明糠醛在碳纳米管修饰电极上的氧化还原过程是受扩散控制的.在pH值为4-10的范围内,随着pH值的增大,糠醛的还原峰电位逐渐负移.通过Tafel曲线、峰电位与pH值的线性关系,计算得到电化学过程中参加反应的电子数为2,质子数为1,电极反应的电子转移系数为0.644.  相似文献   

2.
在玻碳电极表面修饰上羧基化石墨烯制得羧基化石墨烯修饰电极,以此电极为工作电极,研究了多巴胺在此电极上的电化学行为.在pH=3.0的Na:HPO4-C6H8O7,缓冲溶液中,氧化峰电流与多巴胺浓度在1.4×10^-3-1.8×10^-4moL/L的范围内呈良好的线性关系,检出限为5.0×10^-6mol/L.实验结果表明,玻碳电极经羧基化石墨烯修饰后对多巴胺具有明显的电催化作用,灵敏度明显提高.  相似文献   

3.
电化学方法制备聚L-赖氨酸膜(PLL)修饰的玻碳电极上固定氯过氧化物酶,利用循环伏安法研究了修饰电极的电化学行为.修饰一层和两层的CPO修饰电极上均观察到CPO直接可逆的电子传递,其中,修饰两层CPO的电极(CPO/PLL)2/GC的氧化还原峰电流较为明显;氧气饱和的缓冲溶液中的循环伏安曲线显示,(CPO/PLL)2/GC电极上氧的还原峰电流显著增大,且还原峰电位相对于修饰一层CPO的电极正移了150mV,表明修饰两层CPO的电极对氧还原具有更好的电催化效应.(CPO/PLL)2/GC修饰电极应用于原位产生过氧化氢催化苯甲硫醚的反应,得到了目标产物苯甲亚砜,产物的量随电解催化反应时间的增加而增大.实验结果为开发环保、绿色的生物酶催化有机合成反应提供了新思路.  相似文献   

4.
以铂电极为基体,用电沉积方法制备了铁氰化钴修饰电极,研究了该电极的电化学特性及H2O2在该修饰电极上的电化学行为。实验表明,该电极对H2O2具有催化作用;在4.9×10^-5~1.1×10^-3mol/L范围内,峰电流与H2O2的浓度呈线性关系(R=0.9986),检出限为1.3×10^-5mol/L。  相似文献   

5.
研究了熊果苷在多壁碳纳米管修饰玻碳电极(MWCNT/GCE)上的电化学行为,在pH=1的KCl-HCl缓冲溶液中,熊果苷在该电极上有一较灵敏、稳定的氧化峰,电位为0.820V,多壁碳纳米管修饰电极能显著催化熊果苷的电化学反应.提出了一种灵敏、简便的检测熊果苷的电化学方法.在优化条件下熊果苷浓度在8.0×10^-6~9.52×10^-4mol/L范围内与峰电流呈线性相关,相关系数r=0.9985,检出限为6.0×10^-6mol/L.一些常见的共存物质对其测定无干扰,该方法稳定性和重现性好。  相似文献   

6.
本文首次采用Nation和Co(salen)/Nafion修饰铂电极测定海水中的NO,对实验条件进行了选择,确定了最佳实验条件,即反应池通氮除氧30min,富集时间为4min。同时用线性扫描法对海水中的NO进行测定,测得海水中NO的浓度与氧化峰电流之间有一定线性关系。对Nation修饰电极而言,线性范围1~76.9μmol/L,R^2=0.9916,检出限为1μmol/L。同时对2种方法修饰的铂电极进行了比较,即当NO浓度在10^-6mol/L数量级时2种电极基本上无差别,而在10^-7mol/L数量级时Co(salen)/Nalion修饰电极要明显优于Nation修饰电极。  相似文献   

7.
采用粉末微电极来研究修饰和未修饰的碳纳米管电极的电化学特性,结果显示经阳极极化的碳纳米管比未极化的碳纳米管具有明显的催化效果,处理后的碳纳米管修饰的粉末微电极邻苯二酚具有较高的催化活性.  相似文献   

8.
采用3-巯基丙酸在金电极上自组装得到自组装单分子层(SAM),再利用DCC作酰胺键偶合剂,将超氧化物歧化酶(SOD)模型化合物Fe(IDB)CI3(简称Fe-MSOD,IDB为N,N-二(2’-苯并咪唑甲基)亚胺)共价键合到自组装在金电极表面的3-巯基丙酸单分子层上,构筑了一种超氧化物歧化酶模型化合物分子组装体系膜修饰电极(Fe-MSOD/3-MPA/Au).采用电化学循环伏安法、交流阻抗法对该修饰电极进行了表征.初步探讨了此修饰电极的电化学氧化还原性质.  相似文献   

9.
甲醛在聚苯胺修饰分散铂电极上的电催化氧化   总被引:4,自引:0,他引:4  
用循环伏安法和恒电位法在铂电极上分别制备了分散铂电极、聚苯胺修饰电极及聚苯胺修饰分散铂电极,并用循环伏安法研究了制备电极在0.5mol/L H2SO4溶液中的电化学行为以及对甲醛氧化的催化行为,分散铂电极对甲醛氧化的最大电流是6.48mA,是基体电极(0.075mA)的86.4倍,聚苯胺修饰分散铂电极对甲醛氧化的最大电流(15.12mA)是基体电极的201.6倍,分散铂电极的2.3倍,分散铂对甲醛氧化的催化作用不仅仅是铂面积增大的结果,还存在纳米效应,聚苯胺修饰铂电极对甲醛氧化的催化除存在铂进一步分散使面积进一步增大的因素外,还存在铂与聚苯胺的协同作用。  相似文献   

10.
采用涂覆法制备多壁碳纳米管(MWCNT)-离子液体([BMIM]PF6)修饰电极,研究Cu2+在该修饰电极上的阳极溶出伏安行为。考察了实验条件对Cu2+电化学行为的影响。研究表明,Cu2+在修饰电极上可得到灵敏的溶出峰。在优化的实验条件下,Cu2+在1.0×10-6~1.0×10-5mol/L浓度范围内与其氧化峰电流呈...  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.
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   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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   

16.
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   

17.
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   

18.
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   

19.
20.
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   

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