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11.
Non-contact handling in microassembly: Acoustical levitation 总被引:1,自引:0,他引:1
Microassembly is currently of the utmost importance in industry. Nevertheless, the classical assembly processes are no longer usable for very small components, typically ranging from 10 m to 10 mm, since usually neglected surface forces disturb the handling task by inducing adhesion between the component and the gripper. A promising alternative to tackle surface forces consists in levitating the handled component. The various advantages of this contactless handling method are reviewed here and justify the choice of this approach. Consequently, the numerous physical principles suitable for contactless handling are briefly described together with their limitations. The evaluation shows that acoustic levitation is best fitted in the case of microassembly. A classification of literature applications is presented hereafter with special focus on acoustic levitation. Finally, the most common models of acoustical levitation are inspected in a general way. The described models come within the scope of non-linear acoustics. 相似文献
12.
Pierre Darcy Patrick Da Costa Henry Mellotte Jean-Michel Trichard Grald Djga-Mariadassou 《Catalysis Today》2007,119(1-4):252-256
To comply with the new regulations on particulate matter, car manufacturers more and more commonly use diesel particulate filters (DPF). The working of these systems needs to periodically burn soot that has been accumulated during the loading of the DPF. This paper describes the kinetics of the non-catalytic and catalytic oxidation of real diesel soot with oxygen. From these experiments, mechanisms for catalyzed and non-catalyzed soot oxidation have been proposed. 相似文献
13.
Pierre Hadaya 《Electronic Commerce Research》2006,6(2):173-185
Based on the literature dealing with the diffusion of innovation and with information systems, and building on the emerging
concepts in electronic commerce (e-commerce), this paper aims at assessing the influence of various factors on firms’ future
level of use of electronic marketplaces (e-marketplaces). This theoretical model is tested on data collected from 1,200 senior
managers in Canadian firms. Findings indicate that a firm’s past experience in e-commerce, as well as the factors relating
to its business relationships ultimately affect its future use of e-marketplaces. Results of TOBIT regressions also show that
the complexity of sophisticated e-commerce implementations is negatively correlated with the future level of use of e-marketplaces,
and that consultants and other experts play an essential role in encouraging and facilitating the use of this new type of
electronic platform. Finally, our survey data demonstrate that the relative influence of some determinants differs according
to the firms’ size.
Pierre Hadaya is an assistant professor of MIS at the Faculté d’administration of the Université de Sherbrooke (Canada). He holds a Ph.D.
in Management of Technology from the école Polytechnique de Montréal. His research interests lie at the intersection of information
technology management, business strategy and interorganizational design. 相似文献
14.
Bissessur H. Charlet G. Gohin E. Simonneau C. Pierre L. Idler W. 《Electronics letters》2003,39(2):192-193
By transmitting 40 channels over 300 km of TeraLight fibre, it is shown that optical differential phase shift keying can be used in 100 GHz-spaced 40 Gbit/s systems, with direct detection and a simple receiving filter. Chromatic dispersion tolerance around 300 ps/nm is also measured, compared to 70 ps/nm for NRZ. 相似文献
15.
Studied the development of the recognition of emotional facial expressions in children and of the factors influencing recognition accuracy. 80 elementary school students (aged 5–8 yrs) were asked to identify the emotions expressed in a series of facial photographs. Recognition performances were analyzed in relation to the type of emotion expressed (i.e., happiness, fear, anger, surprise, sadness, or disgust) and the intensity of the emotional expression. Age differences were determined. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
16.
This paper gives an account of ‘left’ and ‘progressive’ economic development politics and policy in Sheffield and Chicago in the early 1980s. The origins of these policies in activist work and grassroots organizing, and the leadership of John Benington and David Blunkett in Sheffield and of Robert Mier and Harold Washington in Chicago are characterized and briefly compared. 相似文献
17.
18.
Studied the social reputations of elementary school children. Ss were 76 2nd-grade (mean age 7.5 yrs), 71 3rd-grade (mean age 8.5 yrs), and 83 4th-grade students (mean age 9.7 yrs). Using the peer nomination technique, Ss were assessed collectively on 8 dimensions requiring both social and academic judgments. A cluster analysis was performed to identify groups with different sociometric profiles. Correlations between peer evaluations and teacher evaluations of Ss' social reputations were determined. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
19.
Ferdinand P. Ferragu O. Lechien J.L. Lescop B. Magne S. Marty V. Rougeault S. Kotrotsios G. Neuman V. Depeursinge Y. Michel J.B. Van Uffelen M. Varelas D. Berthou H. Pierre G. Renouf C. Jarret B. Verbandt Y. Stevens W. Voet M.R.H. Toscano D. 《Lightwave Technology, Journal of》1995,13(7):1303-1313
Recent developments of stability control in mines, essentially based on Ge-doped fiber Bragg gratings (FBG) are reported including results about the different aspects of the system: accurate characterizations of FBG, sensor network topology and multiplexing method, user interface design and sensor packaging 相似文献
20.
Lennart Ljung Pierre Priouret 《International Journal of Adaptive Control and Signal Processing》1991,5(6):395-403
The purpose of this paper is to extend recent results of Ljung and Priouret to a more general class of regressors. 相似文献