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排序方式: 共有1704条查询结果,搜索用时 15 毫秒
1.
Thalia Tsiaka Panagiotis Zoumpoulakis Vassilia J. Sinanoglou Constantinos Makris Georgios A. Heropoulos Antony C. Calokerinos 《Analytica chimica acta》2015
High-energy assisted extraction techniques, like ultrasound assisted extraction (UAE) and microwave assisted extraction (MAE), are widely applied over the last years for the recovery of bioactive compounds such as carotenoids, antioxidants and phenols from foods, animals and herbal natural sources. Especially for the case of xanthophylls, the main carotenoid group of crustaceans, they can be extracted in a rapid and quantitative way with the use of UAE and MAE. 相似文献
2.
对石英音叉增强型光声光谱(QEPAS)系统中常用的石英音叉进行了有限元模态计算,获得石英音叉前6阶振型与模态频率,认知了第4阶对称摆动振型为有效振动,利用单因素法分析了石英音叉的音臂长度l1、音臂宽度w1、音臂厚度t、音臂切角θ、音臂圆孔直径d及音臂圆孔高度h对低阶有效共振频率(Fre)的影响,敏感度依次为: l1> w1>d>θ>t>h,考虑实际设计情形,筛选出了l1,w1,d与h四个石英音叉设计变量,采用Box-Behnken实验设计方案与RSM(response surface methodology)方法,以Fre为函数目标,建立l1,w1,d与h的二次回归响应面模型,得到了参数之间的交互作用,利用Design-Expert软件对响应面模型进行设计参数反求,结果表明,在15 000 Hz≤Fre≤25 000 Hz计算区域内误差较小,基本满足QEPAS系统的计算需求,所提出的研究与设计方法具有一定通用性,可为QEPAS系统中石英音叉结构参数设计提供参考。 相似文献
3.
《Electroanalysis》2006,18(24):2435-2440
Several hydroximethylfurfural (HMF) microbiosensors, based on a microelectrode configuration built by photolithographic techniques, have been developed. Two different biosensors based on the aldehyde dehydrogenase (ALDH) enzyme coupling with NADH oxidase (NOD) or diaphorase (Diaph) are described. Experimental variables were optimized using experimental design methodology, by central composite designs, taking the intensity registered for a given HMF solution as response. Given the reproducibility (residual standard deviation (RSD), 7.20%), repeatability (RSD=3%) and limit of detection (LOD)=1.68×10?4 mol dm?3 (α=β=0.05 and a replicate) reached by the ALDH‐Diaph microbiosensor under the optimum conditions, the analysis of HMF in honey was successfully accomplished. 相似文献
4.
Calculus has been witnessing fundamental changes in its curriculum, with an increased emphasis on visualization. This mode for representing mathematical concepts is gaining more strength due to the advances in computer technology and the development of dynamical mathematical software. This paper focuses on the understanding of the function and its derivative as viewed by students of a reformed Calculus 1 course offered in two experimental sections at the Lebanese American University in Beirut, Lebanon. Results have shown that the general approach adopted in the course proved to be unpopular for a great majority of the students, but rewarding for others. Interviews conducted with some students and a study of their performance on very specific exam questions reveal that for most students, the algebraic representation of a function still dominated their thinking; however, these students showed an almost complete understanding of the derivative, particularly the idea of the instantaneous rate of change and/or the slope of a curve at a given point. Furthermore, very few of these students referred to the mechanical methods for finding derivatives. 相似文献
5.
混合位级正交试验设计的极差分析方法 总被引:3,自引:0,他引:3
本文指出,在混合位级的正交试验设计中,以往的极差分析方法存在着不足。本文给出了极差的修正方法,并用大量实例做了数值验证,说明这个修正确实很有效 相似文献
6.
J.-L. Hainaut V. Englebert J. Henrard J.-M. Hick D. Roland 《Applied Categorical Structures》1996,3(1-2):9-45
This paper analyzes the requirements that CASE tools should meet for effective database reverse engineering (DBRE), and proposes
a general architecture for data-centered applications reverse engineering CASE environments. First, the paper describes a
generic DBMS-independent DBRE methodology, then it analyzes the main characteristics of DBRE activities in order to collect
a set of desirable requirements. Finally, it describes DB-MAIN, an operational CASE tool developed according to these requirements.
The main features of this tool that are described in this paper are its unique generic specification model, its repository,
its transformation toolkit, its user interface, the text processors, the assistants, the methodological control and its functional
extensibility. Finally, the paper describes five real-world projects in which the methodology and the CASE tool were applied.
This is a heavily revised and extended version of “Requirements for Information System Reverse Engineering Support” by J.-L.
Hainaut, V. Englebert, J. Henrard, J.-M. Hick, D. Roland, which first appeared in the Proceedings of the Second Working Conference
on Reverse Engineering, IEEE Computer Society Press, pp. 136–145, July 1995. This paper presents some results of the DB-MAIN
project. This project is partially supported by the Région Wallonne, the European Union, and by a consortium comprising ACEC-OSI (Be), ARIANE-II (Be), Banque UCL (Lux), BBL (Be), Centre de recherche public H.
Tudor (Lux), CGER (Be), Cockerill-Sambre (Be), CONCIS (Fr), D'Ieteren (Be), DIGITAL, EDF (Fr), EPFL (CH), Groupe S (Be), IBM,
OBLOG Software (Port), ORIGIN (Be), Ville de Namur (Be), Winterthur (Be), 3 Suisses (Be). The DB-Process subproject is supported
by the Communauté Fran?aise de Belgique. 相似文献
7.
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9.
Some authors claim that reporting the best result obtained by a stochastic algorithm in a number of runs is more meaningful
than reporting some central statistic. In this short note, we analyze and refute the main argument brought in favor of this
statement. 相似文献
10.
Summary We discuss a null experiment to search for the fifth force at ranges around 10 km. It is proposed to use a three-axis gravity
gradiometer to measure the trace of the Earth gravity tensor from a freely falling elevator dropped by a balloon. The main
error sources are considered to some extent.
Paper presented at the V Cosmic Physics National Conference, S. Miniato, November 27–30, 1990. 相似文献