二阶校正法与三维荧光光谱相结合直接测定人体血浆中的水杨酸

水杨酸、萘普生及血浆背景干扰组分,这三者荧光光谱重叠严重,如果不经分离,无法用常规方法定量分析水杨酸.本文利用二阶校正的优势,将三维激发发射荧光光谱与平行因子分析算法和交替三线性分解算法相结合,快速分析测定血浆中的水杨酸.当因子数选为4时,用两种算法获得的回收率分别为(103.8±3.5)%和(98.4±1.4)%.实验结果表明,此方法可用于干扰组分共存下,快速定量测定血浆中的水杨酸,从而可用于研究阿斯匹林的代谢过程.     

激发-发射矩阵荧光结合二阶校正法测定人体血浆样和牛蒡子药材中的牛蒡苷含量

本文利用激发-发射矩阵荧光与二阶校正算法相结合,实现快速测定人体血浆样和牛蒡子对照药材中的牛蒡苷含量.采用二阶校正方法的平行因子分析(PARAFAC)和交替归一加权残差(ANWE)两种算法进行解析,所得血浆基体干扰下牛蒡苷的回收率分别为(98.7±1.4)%和(99.7±1.6)%,实现了对血浆样中的牛蒡苷含茸的直接快速定量测定.此外,用上述两种方法对牛蒡子药材中的牛蒡苷含量进行快速测定,所得结果与液相色谱方法结果进行比较,结果令人满意.实验结果表明,此方法方便快捷,可用于复杂试样中未知干扰共存下牛蒡苷含量的测定.     

三维荧光光谱结合二阶校正算法用于化妆品中芦丁含量的测定

本文利用2种分别基于交替三线性分解算法(ATLD)和自加权交替三线性分解算法(SWATLD)的二阶校正算法与三维荧光光谱相结合,对化妆品中的芦丁进行直接定量分析.当选取组分数为3时,ATLD和SWATLD获得的平均回收率分别为(94.4±2.7)%和(100.2±1.1)%.另外,采用品质因子,如灵敏度(SEN)、选择性(SEL)和检测下限(LOD)评估了这2种算法所得结果的准确性.实验表明这2种算法能成功地用于分析化妆品中芦丁的含量,而且在这个体系中,SWATLD的性能较ATLD稍优.     

三维荧光二阶校正法直接快速测定血浆样中川芎嗪和阿魏酸含量

本文将三维荧光光谱与二阶校正方法相结合用于人体血浆样中的中药药理活性成分川芎嗪和阿魏酸含量的直接测定.尽管预测样存在血浆内源荧光物质的基体干扰,但由于该方法基于“数学分离”的思路和具有“二阶优势”,仍能对荧光光谱严重重叠的血浆样中的目标分析物进行直接同时定量测定,为川芎嗪和阿魏酸在体内的代谢监控及其药效研究提供了一种新思路.获得的预测样中川芎嗪和阿魏酸的平均回收率分别为(95.7±2.2)％和(100.8±2.5)％.该方法简单、快速,结果可靠.     

三维荧光结合交替三线性方法测定中药升麻和人体血浆中升麻素的含量

本文利用化学计量学交替三线性分解(ATLD)方法解析三维荧光数据,在有未知干扰组分共存的情况下,对中药升麻和人体血浆中升麻素的含量和回收率进行了测定,利用核一致诊断法判断得到的组分数是2。中药升麻和血浆体系的背景与升麻素有严重的重叠,用ATLD方法得到的解析光谱与真实光谱几乎完全重合,定量解析结果也令人满意。测定结果显示,标准曲线法和二阶标准加入法得到的中药升麻中升麻素的含量分别为0.061±0.003%和0.055±0.002%,回收率为89.8±4.7%,人体血浆中升麻素的回收率分别为102.7±1.6%。实验结果表明,此法可用于干扰组分共存下中药升麻和人体血浆中升麻素的快速准确定量分析。     

二阶加滞后连续模型的直接辨识

1　引言本文提出了一种新的基于阶跃响应数据直接辨识二阶连续模型参数的算法 ,对文献 [1 ]中的算法进行了推广 ,适用于解决实际工业系统辨识问题 .2　直接法阶跃响应辩识考虑有滞后环节的过阻尼二阶对象G(s) =K(T1 s+ 1 ) (T2 s+ 1 ) e-θs. (1 )阶跃输入幅度为 α时 ,阶跃响应为y(t) =αK 1 -T1 T1 -T2 e- t-θT1+ T2T1 -T2 e- t-θT2 ,t≥θ. (2 )令 T1 =βT2 ,加入白噪声 ω(t) ,则y(t) =αK 1 -ββ -1 e- t-θβT2 + 1β -1 e- t-θT2 +ω(t) ,t≥θ. (3)由于 0≤t<θ时 ,y(t) =ω(t) ,从而∫τ0 y(t) dt=∫τθy(t) dt+ ∫θ…     

自校正α-β跟踪滤波器

本文用现代时间序列分析方法对雷达跟踪系统提出了一种新的自校正α-β跟踪滤波器, 它有如下优点:1)可处理带未知噪声统计和含未知模型参数的跟踪系统;2)基于ARMA新 息模型的在线辨识,可简单地计算α-β滤波器的参数;3)避免解稳态Riccati方程;4)具有渐 近最优(自校正)性.仿真例子说明了其有效性.     

荧光光谱组合二阶校正的芳香族化合物同时测定

芳香族化合物混合体系,由于结构相似导致光谱重叠,难于用常规方法直接定量检测。色谱法则存在操作烦琐、分析时间长等缺陷。本文采用二阶校正中的平行因子分析法与三维荧光光谱相结合,通过数学分离代替化学分离,实现了对邻苯二酚、对苯二酚、酪氨酸、吲哚4种物质的同时定量测定,采用核一致诊断法确定了体系组分数,分辨出了物质的激发光谱和发射光谱。实验结果表明,此方法可用于未知干扰共存下芳烃化合物的同时直接快速定量测定,可用于环境样品中多环芳烃的直接定量测定。     

不同大气校正方法对中小湖泊蓝藻遥感动态监测的影响

环境小卫星可实现中小湖泊蓝藻动态监测,但不同大气校正方法对于相同影像的处理结果有很大差异。研究利用多种大气校正方法对环境小卫星影像进行辐射校正处理,利用多个感兴趣区的全局和局部特征以及多个统计量对处理结果进行分析,比较其在蓝藻动态监测中的作用。基于多光谱植被指数计算蓝藻生物量的思路,分析了影像经不同大气校正算法处理后,其归一化植被指数的差异性来源及其对蓝藻生物量计算结果的影响。结果表明:蓝藻动态监测的定量描述会因大气校正算法不同而不一致,进而对几种大气校正算法在蓝藻生物量监测和定量分析中所产生的不确定性进行了比较分析,并对各算法的有效利用提出了建议。     

汽油管道调合配方优化控制及其应用

配方优化控制是汽油管道调合工艺成套技术的1个重要组成部分,详细论述了开发配方优化控制的过程和算法,并讨论了在某大型石化企业应用的实例.在线配方优化控制集罐底补偿、辛烷值非线性调合规则、非线性配方优化算法于一体,实现调合全过程的优化控制.配方优化是周期运算的过程,通过罐底补偿算法来计算每个优化周期的质量控制要求,与在线校正的调合规则一起构成产品质量约束,利用调合组分和产品的在线分析仪质量反馈信息,根据用户指定的优化目标,在调合设备和调合组分使用等约束条件下,用非线性多目标优化算法在每个优化周期内计算出调合配方,在配方保持过程中得以执行,在确保最终调合产品质量合格的前提下,实现高价值组分的节约和辛烷值过剩最小.以1个批次的调合为例说明罐底补偿控制方式下配方优化的4个阶段,并将组分实际用量与调度设定用量进行比较,MTBE节约了80.4m3,占实际MTBE用量的近20%,RON质量过剩小于0.1个单位,优化效果明显.2008年7月汽油管道调合工艺成套技术通过中国石化股份公司技术鉴定,系统长周期运行稳定,按2007年汽油组分成本计算,因节约高价值调合组分预计可降低生产成本约1 200多万元,经济效益显著.     

A Mathematical Model of Geonavigation in Horizontal Well-boring Control Systems

A mathematical model for determination of the layer boundaries in the horizontal well-boring systems was considered, and a method to resolve it on the basis of the A.N. Tikhonov variational algorithms of determination of the extremal was proposed. The direct problem was solved by the combined method of integral transformations and integral equations.     

A nonrecursive algebraic solution for the discrete Riccati equation

Equations for the optimal linear control and filter gains for linear discrete systems with quadratic performance criteria are widely documented. A nonrecursive algebraic solution for the Riccati equation is presented. These relations allow the determination of the steady-state solution of the Riccati equation directly without iteration. The relations also allow the direct determination of the transient solution for any particular time without proceeding recursively from the initial conditions. The method involves finding the eigenvalues and eigenvectors of the canonical state-costate equations.     

有穷固定模的确定与消除*

本文研究带前馈广义分散控制大系统有穷固定模的确定与消除问题，给出了一种不依赖于系统特征值确定与消除有穷固定模的方法。     

GPS姿态测量分析系统设计

研究导航系统定位优化问题,GPS载波相对定位进行载体姿态测量会受到信号传播误差、天线布局、姿态信息解算方法等因素的干扰,从而导致测姿精度下降。为了有效分析各种干扰因素对测姿系统影响程度,采用GPS载波相位双差定位和直接求解姿态矩阵算法,设计了GPS姿态测量分析系统,开发出能综合分析GPS测姿系统性能的分析软件,并通过实例进行了仿真。仿真结果表明,系统能完成GPS测姿系统定位性能优化的有效性。     

多输入Sigmoid激励函数神经网络权值与结构确定法

结合伪逆直接计算得到神经元之间最优权值的方法,提出了一种双阶段自动搜索与确定最优网络结构的算法,克服了原有BP神经网络模型及其学习算法的固有缺陷。以函数逼近为例,计算机数值实验结果显示了算法有效且耗时短,证实了由该算法得到的网络对于多输入函数具有较优良的逼近(学习与校验)性能。     

Characterization and analytical validation of a microcantilever-based sensor for the determination of total carbonate in soil samples

A microcantilever device has been used as a miniaturized sensor for the determination of total carbonate in soil samples. The method is based on the selective generation of CO₂ (g) from samples and the measure of the pressure effect on the microcantilever sensor located in a closed system. The experimental set-up uses a manifold including the sample reaction minichamber and a dedicated flow-cell designed and built for housing the microcantilever. The response of this sensor was electronically and analytically characterized by using conductance signals. The analytical performance of the sensor was compared to that provided by the conventional quartz crystal microbalance (QCM), demonstrating advantages in terms of sensitivity, linear range of response and resolution. After the optimization of the method, it was validated for its use for direct determination of carbonate in soil samples. The method allowed the determination of carbonate in the 3–75 mg range, with a precision of 1.7%, expressed as relative standard deviation. It was applied to the analysis of different soil samples, obtaining results in agreement with those produced by the official method.     

Design optimization of simply supported concrete slabs by finite element modelling

This paper outlines the finite element prediction process for the development of charts for accurate peak load determination of simply supported, reinforced concrete slabs under uniformly distributed loading. Through a series of parametric studies using a simple concrete model, the simulation of tests on four simply supported slabs was used as a basis for establishing a set of optimum parameter values and computational conditions, which guarantees acceptable solution. The reliability of the established parameter values for prediction purposes was verified by the direct simulation of 11 other slabs. Following the successful reliability check, the finite element model was used for analysing 270 “computer model” slabs, from which charts were developed. These charts serve for quick and reliable peak load determination of arbitrary simply supported slabs. A comparative study of the direct finite element and chart predictions, with values from analytical and design methods, reveals the superiority of the charts over the latter methods, with accuracy comparable to that of the optimised finite element model. The chart prediction is noted to be accurate to within 4% of test results. A strategy for displacement determination is also established, with the same degree of success and the paper discusses possible practical applications of the developed finite element system.     

Refraction and propagation delays in space geodesy

Many measurements to satellites, whether of direct scientific interest or merely for tracking purposes, require a knowledge of the atmospheric propagation delay which affects the observation, The delay has to be precisely determined for such purposes as geodetic or navigation positioning using the TRANSIT system or GPS (Global Positioning system) and gravity-field determination by precise orbit determination using satellite laser ranging. In particular, the high accuracy of satellite altimetry can be severely degraded by propagation delays not only in the altimeter measurement itself but also in the tracking-system observations.

This paper describes the effects of the ionosphere and troposphere on both optical and microwave observations, and discusses both the instrumental and mathematic modelling approaches to the determination of the propagation delay, giving examples of the solution adopted for geodetic, surveying and navigation satellite observations.     

Seismic study of curved bridges using the Rayleigh-Ritz method

The determination of the static and seismic response of curved girder bridges is important and difficult. It is therefore the purpose of this paper to present a direct method for evaluating accurately the mode shapes and the final seismic actions of continuous curved girders supported on high piers, with minimum computation time, using the Rayleigh-Ritz method. Application of the method, compared to the matrix technique, is presented in detail.     

Influence of the canopy BRDF characteristics and illumination conditions on the retrieval of solar-induced chlorophyll fluorescence

The Fraunhofer line discrimination (FLD) principle is the main approach used for the retrieval of solar-induced chlorophyll fluorescence (SIF). The basic assumption of the FLD principle is that the apparent reflectance spectra without SIF in-filling are smooth in the region of the absorption bands. However, in fact, this assumption is not valid due to the so-called ‘direct radiation in-filling’ effect caused by the nonlinear contribution of direct and diffuse radiation at the oxygen absorption bands, which are widely used for ground-based SIF retrieval. In this study, we first analysed the physical mechanism of the direct radiation in-filling effect on the oxygen absorption bands and found that the bias in the SIF retrieval caused by the direct radiation in-filling effect at the oxygen-A (O₂-A) band was less than 20% based on the use of a simulated data set. Second, we established a simple correction model of the direct radiation in-filling effect. We found that the direct radiation in-filling effect at the O₂-A band was directly proportional to the difference between the reflectance of the direct and diffuse radiation, and that the coefficient of proportionality was well correlated with the diffuse-to-global radiation ratio in the form of a quadratic function, with a coefficient of determination (R²) of 0.97. Finally, the model was validated using both simulated and field data sets. The validation results show that the bias in the SIF retrieval caused by the direct radiation in-filling effect can be efficiently corrected using the model proposed in this article. This study thus provides a possible approach to estimating and correcting for the direct radiation-infilling effect using prior knowledge of the bidirectional reflectance distribution function characteristics of direct and diffuse radiation for specific targets.