三氯甲烷萃取——毛细管气相色谱法测定维生素B12生产废水中的丙酸

维生素B12生产产生的废水中含有大量可回收的丙酸,对废水中丙酸的测定进行了研究,建立了测定丙酸的三氯甲烷萃取——气相色谱方法,方法的结果表明:检出限为5×10-2mg/L,精密度RSD为1.32%,加标回收率为97.2%—103.3%。     

Optimal operation of distillation processes under uncertain inflows accumulated in a feed tank

A new method of optimizing the operation of distillation processes with uncertain inflow streams from upstream plants is discussed. The case considered is the streams that will be first accumulated in a tank before feeding to the column. To minimize the total amount of operating energy while keeping a stable column operation under these inflows, a novel decomposed optimization strategy consisting of two steps was used. For an optimal planning of the dynamic operation, a smooth feed flow policy to the column is developed in the first step by stochastic optimization under chance constraints by ensuring a predefined probability of holding the tank level inside the desired range. An easy-to-use method developed computes the maximum reachable probability of holding the constraints so that a feasible solution of the chance constrained problem can be guaranteed. Since the uncertainty in the inflow stream variability is absorbed in the stochastic optimization over the tank, the operation of the dowstream distillation column is deterministic. Therefore, in the second step, the reflux and reboiler duty policies of the column are developed by deterministic dynamic optimization. The optimal overall strategy is obtained by the maximized smoothness of the feed flow to the distillation column. The approach is applied to a pilot column, and the developed operating policies are implemented on the real plant by experiment.     

带有检测迟延的燃料-汽压系统状态观测器设计

由于时延现象的大量存在,时延系统的状态估计问题得到了广泛的研究和重视.针对输出含有时间延迟的燃料-汽压系统,进行了时间延迟补偿观测器的设计.针对不同的时间延迟进行了仿真,实验结果表明,观测器在一定的时间内能够很好地跟踪输出时延系统的状态.     

原料预均化及其在优质矾土生产中的应用

原料预均化的基本原理为“平铺直取”．标准偏差和均化效果是考核均化过程的两个重要指标。标准偏差越小表示物料成分越均匀。原料预均化方式有多种，料仓式原料预均化库综合了各种方式的优点，它具有投资少，密封性好，占地面积小，无粉尘，操作条件和均化效果好等特点。     

Sex phermone components of mulberry looper,Hemerophila atrilineata butler (lepidoptera: Geometridae)

(6Z-9S, 10R)-Epoxy-octadecene (SR-1) and (3Z, 6Z-9S, 10R)-epoxy-octadecadiene (SR-2) are sex pheromone components of the mulberry looper (MBL),Hemerophila atrilineata Butler. Compounds extracted from female MBL pheromone glands were identified by coupled gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometry. In field experiments in China,SR-2,RS-2, or both combined were hardly attractive, butSR-2 in combination withSR-1 attracted significant numbers of MBL males. Synergistic behavioral activity ofSR-1 plusSR-2, but not of corresponding antipode mixtures, indicates enantiospecificity of MBL pheromone communication. Because blends of racemic and enantiospecific (SR)1 plus2 were similarly attractive, racemic1 plus2 may have potential for mass trapping or confusion of MBL males in commercial mulberry plantations.     

Thermogravimetric analysis of methyl methacrylate‐graft‐natural rubber

The thermal degradations of methyl methacrylate‐graft‐natural rubber (MG) at different heating rates (B) in nitrogen were studied by thermogravimetric analysis. The results indicate that the thermal degradation of MG in nitrogen is a one‐step reaction. The degradation temperatures increase along with the increment of heating rates. The temperature of initial degradation (T₀) is 0.448B + 362.4°C, the temperature at maximum degradation rate, that is, the peak temperature on a differential thermogravimetric curve (T_p) is 0.545B + 380.7°C, and the temperature of final degradation (T_f) is 0.476B + 409.4°C. The degradation rate at T_p is not affected by B, and its average value is 48.9%; the degradation rate at T_f is not affected by B either, and its average value is 99.3%. The reaction order (n) is 2.1 and is not affected by B. The reaction activation energy (E) and the frequency factor (A) increase along with B, and the apparent reaction activation energy (E₀) is 254.6 kJ/mol. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2952–2955, 2002     

基于梯度功能的陶瓷水煤浆喷嘴的设计

在分析水煤浆喷嘴工作特性和磨损机理的基础上,提出了梯度功能陶瓷水煤浆喷嘴的设计模型,’并对单向梯度功能陶瓷喷嘴的残余应力进行了有限元分析。结果显示,梯度功能陶瓷喷嘴内部的残余压应力能缓解喷嘴工作时的热应力,提高陶瓷喷嘴的抗热冲蚀磨损能力。     

图计算加速器中稀疏向量比较单元的设计与实现

绝大多数图计算应用都可以映射为稀疏矩阵和向量运算,稀疏向量的比较运算是稀疏矩阵向量运算的计算瓶颈,为解决图计算加速器中稀疏矩阵列向量比较问题,设计一种稀疏向量比较运算电路,主要包括64个比较运算电路和一个共享存储单元.基于Verilog HDL语言完成电路设计,以SNAP(Stanford Network Analysis Project)上的Flickr数据集为例,在ModelSim SE-6410.1 c完成验证工作,采用Xilinx公司的ISE开发环境对硬件电路进行综合,实验结果表明,该电路的工作频率可以达到264 MHz.     

Expectation Maximization Algorithm for Time-delay Output-error Models Based on Finite Impulse Response Method

International Journal of Control, Automation and Systems - In this paper, an output error (OE) model with random time delay is identified by using the expectation maximization (EM) algorithm. Since...     

基于贝叶斯模型与最佳伙伴相似度量的目标跟踪

提出了一种基于产生式与判别式联合模型的视觉目标跟踪算法。首先介绍了一种基于全局颜色特征直方图特征的贝叶斯分类器,检测出若干最有可能属于目标的候选区域,然后利用最佳伙伴相似性度量（Best-Buddies Similarity）得到候选区域与目标模板的相似度,结合概率值与相似度值估计出最优的目标状态。通过划分目标-背景区域模型、目标-干扰区域模型,对可能产生干扰的区域提前进行抑制,降低了长期跟踪可能产生的漂移问题的风险,同时引入了自适应尺度估计机制和在线模型更新策略,以获得更为精准的跟踪结果。在37组具有挑战性的图像序列上与7种优秀的算法对比实验表明,所提出的算法能够有效应对光照变化、遮挡、旋转与尺度变化等多种问题。