Near-infrared imaging for quantitative analysis of active component in counterfeit dimethomorph using partial least squares regression

Near-infrared (NIR) imaging systems simultaneously record spectral and spatial information. Near-infrared imaging was applied to the identification of (E,Z)-4-(3-(4-chlorophenyl)-3-(3,4-dimethoxyphenyl)acryloyl)morpholine (dimethomorph) in both mixed samples and commercial formulation in this study. The distributions of technical dimethomorph and additive in the heterogeneous counterfeit product were obtained by the relationship imaging (RI) mode. Furthermore, a series of samples which consisted of different contents of uniformly distributed dimethomorph were prepared and three data cubes were generated for each content. The spectra extracted from these images were imported to establish the partial least squares model. The model??s evaluating indicators were: coefficient of determination (R ²) 99.42 %, root mean square error of calibration (RMSEC) 0.02612, root mean square error of cross-validation (RMSECV) 0.01693, RMSECV_mean 0.03577, relative standard error of prediction (RSEP) 0.01999, and residual predictive deviation (RPD) 15.14. Relative error of prediction of the commercial formulation was 0.077, indicating the predicted value correlated with the real content. The chemical value reconstruction image of dimethomorph formulation products was calculated by a MATLAB program. NIR microscopy imaging here manifests its potential in identifying the active component in the counterfeit pesticide and quantifying the active component in its scanned image.     

非Lipschitz渐近伪压缩映象不动点的迭代逼近

本文在任意实的Banach空间中研究了用具误差的修正的Ishikawa与Mann迭代程序来逼近非Lipschitz的渐近伪压缩映象不动点的强收敛性问题;在去掉条件"‖Tnxn-xn‖→0(n→∞)"及"{xn}有界"之下,证明了相关文献的结果仍然成立.所得结果改进和推广了最近一些人的最新结果.     

HPLC同时测定大黄剂中的5种蒽醌类衍生物

建立了中成药中多种蒽醌类化合物(芦荟大黄素、大黄酸、大黄素、大黄酚和大黄素甲醚)的含量测定方法,为中国药典中含蒽醌的中成药提供一致的测定方法.色谱柱Agela Venusil XBP-C18柱(4.6mm×250mm,5μm);流动相为乙腈-0.1％磷酸溶液,梯度洗脱;检测波长为226nm;流速为1.0mL·min-1;柱温为40℃.芦荟大黄素、大黄酸、大黄素、大黄酚和大黄素甲醚分别在0.040-1.200、0.010-1.200、0.040-1.200、0.040-1.200、0.020-0.600μg范围内呈良好的线性关系,相关系数分别为0.9998、0.9997、0.9991、0.9997、0.9993,平均回收率(n=9)分别为99.26％-102.18％(RSD1.68％-2.64％)、98.85％-99.61％(RSD 1.02％-1.94％)、100.29％-104.65％(RSD 1.90％-2.57％)、97.68 ％-98.68％ (RSD 1.47％-2.53％)、96.18％-100.21％ (RSD 1.57％-2.82％).方法快速简便,重复性好,测定结果准确可靠,能够用于大黄剂中蒽醌类衍生物的含量测定.     

基于偏最小二乘回归的类模型方法用于中药牛黄的真伪鉴别

针对独立软模式类簇法(SIMCA)在确定主成分数和决策区间时遇到的困难,提出了一种基于PLSR的类模型方法——PLS类模型方法(PLSCM)。通过把类描述问题转化为常见的PLSR问题,采用成熟的蒙特卡罗交互验证法确定模型的隐变量数和决策区间。采用本方法对不同牛黄样品的近红外光谱数据(波长范围4000～9000 cm-1)进行分析,可成功鉴别牛黄的真伪。本方法的可操作性和鉴别准确率均优于经典的SIMCA方法。对于原始光谱数据,PLSCM的训练和预测准确率均为100%,对于经SNV处理的数据,训练和预测准确率分别为99%和100%。     

Rapid Synthesis of Monodisperse Polystyrene Microspheres and Self-Assembly of Colloidal Crystals on Mica

Polystyrene (PS) colloidal particles were prepared in aqueous solution by a quick emulsifier-free emulsion polymerization (EFEP) method. The scanning electron microscopy (SEM) images indicate that the as-synthesized particles have good sphericity and uniform size (dispersion coefficient C_v is less than 5%). The monodisperse PS microspheres with different diameter were obtained easily by varying the monomer concentration. The atomic force microscopy (AFM) images show that the PS microspheres were self-assembled into three-dimensional ordered structure on micas by dropping-casting method. The self-assembly method is simple and quick. Based on the experimental results, a possible self-assembly mechanism was proposed.     

固相萃取-高效液相色谱-串联质谱法测定中药西南金丝梅中26种农药残留量

提出了高效液相色谱-串联质谱法测定西南金丝梅中26种农药残留量的方法。样品用乙腈振荡提取,提取液经氨基固相萃取小柱净化。用shim-packXR-ODS色谱柱分离,采用电喷雾离子化正离子方式及多反应监测模式进行测定。26种农药的质量浓度在0.01～2.5mg·L-1范围内与峰面积呈线性关系,检出限(3S/N)在4.16×10-5～2.85×10-4 mg·kg-1之间。在3个标准加入水平下进行了精密度和回收试验,方法的回收率在78.4%～112%之间,测定值的相对标准偏差(n=5)在1.2%～11%之间。     

2011年3月10日盈江5.8级地震诱发砂土液化灾害特征研究

2011年3月10日中缅边境附近的云南省德宏傣族景颇族自治州盈江县发生Ms5.8级地震,震源深度10km,造成25人死亡, 250人受伤, 13万人口受灾,众多构(建)筑物损毁,砂土液化广泛发育,约19km长的盈江河堤开裂。5.8级地震诱发如此大的次生灾害是近年来少有的。通过对本次地震地质背景和地质灾害调查分析,初步认识到:(1)本次地震是2011年初盈江4级震群继续增强活动的结果,近年来盈江地区地震群总体上呈现沿苏典断裂带从北至南逐渐迁移的趋势,本次地震是这一趋势的延续,位于苏典断裂南端,主余震显示本次地震破裂为苏典断裂与大盈江断裂的共轭破裂; (2)砂土液化是本次盈江地震震损严重的主要原因之一,在地表产生喷沙冒水、砂土体侧向滑动、地面开裂和下沉等次生地质灾害,对房屋、江堤、道路、水利设施和电线杆等构(建)筑物造成了较大破坏作用; (3)砂土液化主要发育在大盈江全新世粉细砂冲积层分布区,严重液化区主要为盈江的老河道,构(建)筑物损毁程度与液化区范围和强度有较好的对应关系,而晚更新世砂砾地层作为盈江的二级阶地不仅地势高、防洪能力强,其地基基础承载力高,抗砂土液化能力强,是盈江盆地内工程地质条件较好的地块,未发现砂土液化且构(建)筑震损轻微,可作为当地城镇未来规划发展的首选区域。     

Intelligent quadratic optimal synchronization of?uncertain chaotic systems via LMI approach

This paper proposes an intelligent quadratic optimal control scheme via linear matrix inequality (LMI) approach for the synchronization of uncertain chaotic systems with both external disturbances and parametric perturbations. First, a four-layered neural fuzzy network (NFN) identifier is constructed to estimate system nonlinear dynamics. Based on the NFN identifier, an intelligent quadratic optimal controller is developed with robust hybrid control scheme, in which H _?? optimal control and variable structure control (VSC) are embedded to attenuate the effects of external disturbances and parametric perturbations. The adaptive tuning laws of network parameters are derived in the sense of the Lyapunov synthesis approach to ensure network convergence, and the sufficient criterion for existence of the controller is formulated in the linear matrix inequality (LMI) form to guarantee the quadratic optimal synchronization performance. Finally, a numerical simulation example is illustrated by the chaotic Chua??s circuit system to demonstrate the effectiveness of our scheme.     

Ionic liquid-based single drop microextraction of ultra-trace copper in food and water samples before spectrophotometric determination

In this work, room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim]PF6) was used as extractant in single drop microextraction (SDME). The traditionally volatile organic extractants were substituted by this green reagent, which changed SDME preconcentration into environmentally friendly method, relatively. After this pretreatment, ultra-trace copper in water and food samples could be accurately detected by spectrophotometer. This study was focused on the improvement of the analytical performance of spectrophotometric determination, expanding its applications. The influence factors relevant to IL-SDME, such as absorption spectra of complex, drop volume of RTIL, stirring rate and time, concentration of chelating agent, pH, and salt effect were studied systematically. Under the optimal conditions, the limit of detection (LOD) was 0.15 μg L(-1) with an enhancement factor (EF) of 33. The proposed method was green, simple, rapid, sensitive, and cost-efficient.     

关于概率论中的分段函数问题

分段函数在概率论中有着广泛的应用.通过对几个概率问题的研究,探讨针对分段函数如何合理分段或分区域进行积分问题,体现分段函数在概率论中的重要性.