EDTA掩蔽-络合物吸附催化波极谱法测定锌电解液中钴

在丁二酮肟(DMG)和亚硝酸钠存在的氨水-氯化铵缓冲介质中,以EDTA作掩蔽剂,建立了测定锌电解液中钴的络合物吸附催化波极谱法。探究了掩蔽剂EDTA用量的选择,结果表明:所需EDTA的量与溶液中锌的含量有关,当EDTA与锌的物质的量比n_EDTA/n_Zn为1.15时为最佳选择,此时可消除锌电解液中高浓度锌及其他共存杂质金属离子对测定痕量钴的干扰。对底液酸度、氨水-氯化铵缓冲液用量、丁二酮肟乙醇溶液用量和亚硝酸钠溶液用量,以及静置时间等进行了优化。结果表明,在优化的实验条件下,钴的浓度分别在5.0×10^-11~5.0×10^-9和5.0×10^-9~3.2×10^-7mol/L范围内时与其对应的二阶导数波峰电流I_p(nA)呈良好的线性关系,相关系数分别为0.9980和为0.9997,方法检出限为2.0×10^-12mol/L。将实验方法应用于中性上清夜、锌电解新液和除钴后液等实际样品分析,测定值与国标方法GB/T 223.22—1994(亚硝基R盐分光光度法,NRS)比较,相对误差(RE)在±4.5%范围内,相对标准偏差(RSD,n=6)不大于2.7%。方法线性范围宽,对锌电解液中钴的测定具有很高选择性,适用于湿法冶金过程控制分析。     

基于潮流熵的继电保护定值在线校核评估方法

为了提高继电保护整定值在线校核的效率,提出按照各支路的重要度对继电保护整定值进行有序校验。部分支路受潮流冲击后易故障,且断开后易引起连锁故障,所以提出利用潮流熵评估支路重要度。利用基于潮流转移熵的指标Q1i评价了支路因故障断开后引发连锁故障的可能性,利用基于潮流分布熵的指标Q2i评价了支路抵抗潮流冲击的能力。采用Q1i、Q2i的乘积对支路重要度进行综合评价。利用IEEE 3机9节点系统上的仿真算例验证了所提方法的正确性。最后为了简化计算过程,提出采用分布系数法计算各支路的潮流变化。     

化学振荡反应及其在分析化学中的应用

近些年来,振荡反应受到了相当的重视,用途越来越广泛,本文概述了振荡反应的分类及其在分析化学领域中的应用,同时展望了化学振荡的未来。     

装载转运车牵引转向机构优化设计与分析

目前,应用于仓储货物装载转运的牵引车辆多采用平行四边形牵引转向机构,因转向轮不符合阿克曼原理,转向时滑动摩擦力大,从而会导致牵引转向操作费力.设计了一种基于阿克曼原理的梯形牵引转向机构,并运用多元非线性规划序列二次规划遗传算法对梯形牵引转向机构的构件尺寸进行优化运算,得到了更加贴合阿克曼理论曲线的尺寸参数.根据优化后的参数制作了样机,通过动力学仿真软件从转向轨迹、转向启动力矩、能量转化效率3个维度对梯形转向机构与优化前平行四边形机构进行了仿真对比实验.结果表明,优化之后的机构具有更平滑的转向轨迹、更小的转向启动力矩以及更高的能量转化效率.     

MZ-1A型非线性化学指纹图谱智能分析仪

非线性化学指纹图谱分析仪是根据非线性化学反应原理,利用不同化学成分对非线性化学反应的不同影响,运用智能软件技术和检测条件优化技术,通过测定化学体系非平衡反应信号来获得表示复杂样本成分群集特征的指纹图谱,以实现其定性鉴别和定量分析的仪器。其用途十分广泛。     

食醋非线性化学指纹图谱掺伪鉴别原理的研究

针对食醋掺伪问题对食醋非线性化学指纹图谱进行研究。通过对"溴酸钠-硫酸锰-硫酸-丙酮"体系的振荡机理的分析及食醋成分分析探讨食醋非线性化学指纹图谱的原理。通过正交试验考察建立食醋非线性化学指纹图谱的条件,并考察总酸、食盐、防腐剂对食醋非线性化学的影响。结果表明,食盐、山梨酸对食醋非线性化学指纹图谱影响较大,应在试验前去除食醋样品中的盐分;在检测过程中,应严格控制振荡体系中物种及其浓度、电极类型、温度、搅拌速率、食醋用量。食醋非线性化学指纹图谱是食醋众多成分的整体表征,而不是一种或几种物质的体现,能表达食醋的真正质量,为食醋的掺伪鉴别和质量评价提供一种新的方法。     

非线性化学指纹图谱在啤酒花鉴别评价中的应用

利用啤酒花成分、溴酸钠、硫酸锰、硫酸和丙酮组成的非平衡化学体系,研究了两种啤酒花的非线性化学指纹图谱,并对其进行了系统相似度计算.利用指纹图谱的直观特征和参数信息,对两种不同的啤酒花进行了种类鉴别和质量评价.结果表明,非线性化学指纹图谱技术为啤酒花的真伪和品种鉴别及其质量评价提供了一种快速、简便和准确的方法.     

利用非线性化学指纹图谱鉴别人参真伪和产地

利用非线性化学指纹图谱对7个不同产地的人参及其伪品以及其它参类进行研究,提出鉴别人参真伪和产地的新方法。向"硫酸-硫酸锰-丙酮-溴酸钠"混合液中加入样品,产生非线性化学反应,通过优化反应条件,检测不同产地和种类样品的指纹图谱,并确定其系统相似度。结果表明:样品用量为0.6g,反应温度为37℃时,样品非线性化学指纹图谱具有良好重现性和特征性。不同种类的样品具有明显不同特征的指纹图谱;同一产地人参的系统相似度在0.9712~0.9920之间,而不同产地人参的相似度在0.7548~0.9403范围内。利用人参非线性化学指纹图谱的直观特征和系统相似度可分别准确地鉴定人参的真伪和产地。     

Systematically structural identification of nitriccompounds in crude oil with chemometric resolution

Aimed at the problem of classification of non-hydrocarbons of crude oil, the theoretical standpoint that the polarity of a compound depends on the whole structure and composition of molecule instead of a kind of heteroatom or its functional group was presented. A method was established for the systematically structural identification of nitric compounds in crude oil. The pre-fractionation of a crude oil sample into 7 fractions was performed by diadsorption column chromatography with neutral aluminum oxide and silica gel. Subsequently, the individual components were obtained by using capillary column gas chromatography, and the types of compounds were detected by a mass spectrometer. In combination with a chemometric resolution, the compounds of fraction were further identified. This method can relieve the difficulty of classical analysis in identifying those species with very low contents or without being completely separated. The structures of 168 nitric compounds in a crude oil sample were determined by this method.     

Quantitative similarity assessment of non-linear chemical fingerprint of traditional Chinese medicine by similarity system theory

The similarities of the non-linear chemical (NLC) fingerprints of Radix Glycyrrhizaes from four producing areas and eight other traditional Chinese medicines (TCMs) were calculated, using a systemic similarity calculation method proposed and three other main calculation ones (Euclidean distance, correlation coefficient and included angle cosine). All of the correlation coefficient similarities of different TCMs are higher than 0.952, and the included angle cosines are all higher than 0.962. So, both the correlation coefficient and included angle cosine similarities are unable to be used as the criteria for quantitatively evaluating the similarities of NLC fingerprints of TCMs. Although all of the Euclidean distance similarities of Berry Liquorices from four producing areas are less than 73, those of the other eight TCMs are all more than 180. The Euclidean distance cannot reflect the relative magnitudes of the feature differences in the NLC fingerprints very correctly. The systemic similarity method is the best among the four ones. All of the systemic similarities of Berry Liquorices from the four producing areas are higher than 0.962, while those of the other eight TCMs are all lower than 0.805, and the systemic similarity can reflect the differences between samples most faithfully, and can be used as a quantitative one evaluating the similarities of NLC fingerprints of TCMs, by which TCM could be distinguished and evaluated quickly, simply and exactly.