共查询到20条相似文献,搜索用时 31 毫秒
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Conventional multivariate statistical methods for process monitoring may not be suitable for dynamic processes since they usually rely on assumptions such as time invariance or uncorrelation. We are therefore motivated to propose a new monitoring method by compensating the principal component analysis with a weight approach. The proposed monitor consists of two tiers. The first tier uses the principal component analysis method to extract cross-correlation structure among process data, expressed by independent components. The second tier estimates auto-correlation structure among the extracted components as auto-regressive models. It is therefore named a dynamic weighted principal component analysis with hybrid correlation structure. The essential of the proposed method is to incorporate a weight approach into principal component analysis to construct two new subspaces, namely the important component subspace and the residual subspace, and two new statistics are de-fined to monitor them respectively. Through computing the weight values upon a new observation, the proposed method increases the weights along directions of components that have large estimation errors while reduces the influences of other directions. The rationale behind comes from the observations that the fault information is associated with online estimation errors of auto-regressive models. The proposed monitoring method is exem-plified by the Tennessee Eastman process. The monitoring results show that the proposed method outperforms conventional principal component analysis, dynamic principal component analysis and dynamic latent variable. ? 2016 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. Al rights reserved. 相似文献
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通过理论分析和计算机仿真研究了经典切削颤振模型的稳态误差,发现该误差值随切削条件的变化而大幅度变化,这导致数控机床切削动态特性的仿真结果严重失实。在分析经典模型不足的基础上建立了一个新的切削颤振模型,理论分析和仿真表明新模型的稳态误差趋于零,它为数控机床的切削动态特性仿真提供了可靠的数学模型。 相似文献
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Francis G. Mayne Michel O. Boniface Brigitte G. Boniface Michel M. Traisnel 《Powder Technology》1975,12(2):103-110
In the field of particles analysis by microscopy, a comparison of estimation of areas of projected surface of particles has been made by simulation.Three methods have been studied: the B.S. 3406 graticule, a rectangle graticule derived from that proposed by B.S. 3406 and a new method with squared reference grids.The results have been tested by a variance analysis on a balanced incomplete block design.In the case of non-uniform particles, it seems possible to advocate the new grids method. 相似文献
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通过对国内外部分全氧燃烧玻璃窑炉的寿命统计,非正常停炉和常见故障等问题分析,找出影响窑炉寿命的因素,提出要以规范化、科学化、系统化的思维,通过新材料、新技术、新工艺的运用有效延长全氧燃烧玻璃窑炉的寿命,对目前全氧燃烧窑炉的建设、推广应用有积极的参考价值。 相似文献
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国产染色淀粉片剂法检测工业α—淀粉酶的活力 总被引:1,自引:0,他引:1
我们采用具有双反应基团的国产活性染料M-8B与马铃薯淀粉经共价结构制成的红色染色淀粉片,已可成苗取代原有国外淀粉片剂检测工业用α-淀粉酶的活力检测。新开发的方法可缩短反应时间、简化检测工艺、降低检测成本,并且所得的精密度和准确度均可满足用户需要。 相似文献
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A new, rapid method for total oil analysis of soybeans is proposed in which ground soybeans are mixed with solvent and further
ground in a closed homogenizer until the oil is completely dissolved. A sample of the slurry can then be filtered and the
oil content determined by evaporating the solvent from a measured amount of miscella. Parameters studied included times and
speeds needed to produce sufficiently small particles so that all the oil was dissolved. The new analysis compared favorably
with conventional Goldfisch extraction for total oil of soybeans. Preliminary experiments indicated that rapeseed could be
extracted by the new procedure without preliminary grinding.
Published with the approval of the director of the Arkansas Agricultural Experiment Station. 相似文献
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Kyung Hwan Ryu Changkyu Lee Go-Gi Lee Sungkoo Jo Su Whan Sung 《Korean Journal of Chemical Engineering》2013,30(10):1946-1953
A new simulation logic and thermodynamic equilibrium analysis algorithm combined with a new model simplification technique was developed to simulate the solvent extraction process for purifying rare earth metals from chloride solution with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC88A) as a solvent. The proposed model simplification method significantly reduces the number of the nonlinear equilibrium equations to be simultaneously solved to overcome the initial guess problem and obtain numerically stable convergence pattern in solving the equilibrium analysis problem and performing the rigorous simulation of the extraction process. A new equilibrium analysis algorithm on the basis of the simplified nonlinear equilibrium equations is also proposed to estimate the equilibrium concentrations by solving the rigorous first principle extraction model. Finally, a solvent extraction simulator is developed to estimate all the concentrations of all the stages of the solvent extraction process by solving the equilibrium analysis problem at each stage in a sequential way. The proposed simulator doe not suffer from the initial guess problem and shows very robust convergence pattern without any numerical problems. 相似文献
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将分形和分数维概念用于碱矿渣水泥硬化体中微孔结构的研究,并通过对压汞仪测定孔结构(mercury intrusion porosimetry)测试数据的分析证明:碱矿渣水泥硬化体中微孔结构具有分形特征,其容积分数维越大,微孔占有空间的结构越复杂.因此,该方法为水泥硬化体中微孔结构的研究提供了一种新方法. 相似文献
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《Ceramics International》2017,43(16):13119-13126
The cult MAX phases and MXenes has been a point of an attractive new family of 2D materials for diverse applications. In the present work, titanium carbide MXene sheets have been prepared by etching aluminium from titanium aluminium carbide MAX phase. The sample was investigated by X-Ray diffraction, FESEM, TEM and RAMAN analysis. XRD analysis revealed that the synthesized MXenes were formed in hexagonal crystal system and FE-SEM analysis showed that titanium carbide sheets were exfoliated. Raman analysis showed that the lower modes, which correspond to the “A” phase, disappeared due to the removal of aluminium. The electrochemical performance of the synthesized MXenes towards supercapacitor applications was further investigated using various electrochemical techniques like cyclic voltammetry (CV), charge-discharge and impedance analysis. Results showed that the new material showed an excellent performance in charge storage applications. 相似文献
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Tanmay Chattopadhyay Kazi Sabnam Banu Soubhik Chattopadhyay Arpita Banerjee Sandip Mondal Eringathod Suresh Debasis Das 《Inorganic chemistry communications》2009,12(1):26-28
A new coordination chemistry of sodium has been developed by complexing it with a non-chelating neutral nitrogen donor ligand hexamethylenetetramine (urotropine) in presence of cadmium(II) iodide and the new coordination compound has been characterized by X-ray single crystal structural analysis. 相似文献