Determination of quaternary alkylammonium compounds by capillary zone electrophoresis and indirect UV detection as a real alternative to ion chromatography with suppressed conductivity detection

A capillary electrophoretic (CE) method for the determination of residual mid-chain alkyltrimethylammonium compounds in the pharmaceutical product Welchol™ (an alkylated, crosslinked polyallylamine) was developed, validated and compared with the existing ion chromatographic (IC) method with suppressed conductivity detection. Excellent reproducibilities of migration times (RSD<0.5% within a series of 55 sample injections) and relative peak areas (RSD<2%) make the method suitable for quality control as a real alternative to IC. Limits of quantification of 0.01% w/w of each impurity in the active substance were achieved. Buffer systems for indirect UV detection based on creatinine as visualization reagent with different inorganic and organic acids (phosphoric, sulfuric, formic, acetic, oxalic and citric acid) and their effect on selectivity to ten quaternary ammonium compounds were studied. Selectivity changes were observed for the di- and trivalent analytes depending on the buffer applied. Also, the influence of acetonitrile, methanol, 1,4-dioxane and tetrahydrofuran on selectivity was investigated. In addition, CE–MS experiments were carried out in order to identify several impurities in the product.     

镧系四元混合配体配合物[Ce(CH2ClCOO)2(NO3)(phen)(H2O)]2的晶体结构、芳环堆积效应和2D氢键网络

The quaternary complex, ［Ce(CH2ClCOO)2(NO3)(phen)(H2O)］2, was synthesized. Interestedly, the title compound is a dimer comparing with the 1D polymer ［La(CH2ClCOO)2(NO3)(phen)*(H2O)］n and powder compound ［Nd(CH2ClCOO)2(NO3)(phen)］. In the title compound there is a monodentate NO-3, which is a first example in the all synthesized quaternary mixed anion complexes, and the NO-3 extended the complex into a 2D network with water from other molecules by inter-molecular hydrogen bonds. The intermolecular hydrogen bonds lead to the weaker Ce—O(COO), Ce—O(NO3) and Ce—N bonds comparing with other quaternary mixed anion complexes of cerium. Also the stacking effect, which makes the compound more stable in the situation of weaker Ce—O and Ce—N bonds, was first found in the series compounds.     

Intelligent Fault Diagnosis of Rolling-Element Bearings Using a Self-Adaptive Hierarchical Multiscale Fuzzy Entropy

The fuzzy-entropy-based complexity metric approach has achieved fruitful results in bearing fault diagnosis. However, traditional hierarchical fuzzy entropy (HFE) and multiscale fuzzy entropy (MFE) only excavate bearing fault information on different levels or scales, but do not consider bearing fault information on both multiple layers and multiple scales at the same time, thus easily resulting in incomplete fault information extraction and low-rise identification accuracy. Besides, the key parameters of most existing entropy-based complexity metric methods are selected based on specialist experience, which indicates that they lack self-adaptation. To address these problems, this paper proposes a new intelligent bearing fault diagnosis method based on self-adaptive hierarchical multiscale fuzzy entropy. On the one hand, by integrating the merits of HFE and MFE, a novel complexity metric method, named hierarchical multiscale fuzzy entropy (HMFE), is presented to extract a multidimensional feature matrix of the original bearing vibration signal, where the important parameters of HMFE are automatically determined by using the bird swarm algorithm (BSA). On the other hand, a nonlinear feature matrix classifier with strong robustness, known as support matrix machine (SMM), is introduced for learning the discriminant fault information directly from the extracted multidimensional feature matrix and automatically identifying different bearing health conditions. Two experimental results on bearing fault diagnosis show that the proposed method can obtain average identification accuracies of 99.92% and 99.83%, respectively, which are higher those of several representative entropies reported by this paper. Moreover, in the two experiments, the standard deviations of identification accuracy of the proposed method were, respectively, 0.1687 and 0.2705, which are also greater than those of the comparison methods mentioned in this paper. The effectiveness and superiority of the proposed method are verified by the experimental results.     

容错技术及其在过程控制中的应用

对过程控制中的容错技术进行了研究。从化工、电力、冶金等 一产过程的安全经济运行与控制需要出发,结合过程控制技术的发展现状,介绍了容错过程控制的基本思想,在对近年来容错技术在过程控制系统中的应用研究情况进行回顾与评价的基础上,综述性地提出了今后的若干研究发展方向。     

多期叠合盆地油气运聚模式

多期叠合盆地的主要特征是盆地经历了多个演化阶段,并且在不同演化阶段中具有不同的盆地类型和性质。对中国西北塔里木和柴达木盆地进行了多期叠合盆地油气运聚研究。这两个盆地自塬旦纪以一经历了震旦纪－交替转化,形成了油气来自多源、油气形成多期、油气运移多方向、油气聚集多场所的油气运聚特征。多期叠合盆地有３种基本油气运聚模式;（１）放射状运移、太聚集模式,以柴达木盆地西部环英雄岭构造带为代表,油气运移方向垂直     

解调分析在机械设备故障诊断中应用的三个局限性研究

在具有齿轮、滚动轴承的机械设备故障诊断中,广泛使用解调方法分析诊断故障．从理论上分析．现有的解调分析方法存在的三个局限性：将不包括调制信息（故障信息）的两时域相加信号,也以其频率之差作为解调信号而解出;广义检波滤波解调分析中,由于取绝对值或检波过程可能产生混频效应;几种细化解调分析算法中,无法在细化分析的选抽时进行数字低通滤波,有可能会出现调制频率的高次谐波发生频率混叠而反折到低频部分的现象,提出了基于复解析带通滤波器的优化希尔伯特变换解调方法,将解调分析频率与滤波带宽建立严格的数学关系,可以克服三个局限性,将带通滤波、希尔伯特变换及选抽合为一体．运算速度快,是最佳的解调分析方法．     

基于DSP的数据采集及故障录波模块

介绍了一种集数据采集与故障录波功能于一体的模块设计和一种利用双端口RAM在多CPU系统中实现数据共享的方法。     

演化神经网络诊断模型隐层节点自生成算法的探讨及应用

在将演化计算方法引入径向基函数 (RBF)网络训练的基础上 ,建立了一个故障诊断模型 ,给出了一种隐层节点自生成的学习方法 ,并在齿轮的故障诊断应用中得到验证 图 2 ,表 1 ,参 5     

洪浩尔舒特凹陷海流特构造群成藏条件分析

在对洪浩尔舒特凹陷东次洼海流特构造群腾二段的勘探中 ,利用储层预测、作波阻抗剖面、拉任意线作精细构造图等先进的勘探技术 ,对腾二段油藏的形成条件进行了分析 ,得出如下结论 :该区油气资源较丰富 ,腾一段为主要油源层 ;反转构造活动强烈 ,断裂及褶皱发育 ;主构造区发育物性较好的储层 ,形成了有利的圈闭 ;油气与圈闭条件的有机配合形成了油藏 ,指明了今后的勘探方向 .     

伸展断层作用对油气二次运移的影响

伸展断层是沉积盆地中的主要构造形迹。伸展断层作用不仅控制着构造圈闭的形成及沉积体系的分布 ,而且也是盆地内成熟油气垂向运移的主干通道。由伸展断层及其邻近地层中的次级断层活动产生的“地震泵”作用是油气二次运移的重要动力源之一。在复杂断块区 ,与“地震泵”所毗邻的储集层是主要的油气富集层段。在判断“地震泵”作用的层位及深度时 ,可以采用构造几何学方法与局部平衡剖面法进行综合分析。根据局部平衡剖面恢复所得到的关键油气运移期的局部伸展量变化曲线 ,可标定出某一断块区的主干伸展层段 ,确定出主干伸展层对预测油气富集的地质层位 ,据此可指导勘探目的层的优选。本文给出了应用实例