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1.
By contrast to design meetings, design evaluation meetings (DEMs) have generally been considered as situations in which, according to DEM methodologies, design activities are quite marginal. In a study of DEMs in software development, i.e. in technical review meetings following a particular review methodology, we showed: (i) the occurrence of design activities as part of an argumentation process; (ii) the relative importance of cognitive synchronisation as a prerequisite for evaluation; (iii) the important role played in evaluation by argumentation that makes explicit the underlying design rationale (DR). On the basis of our results, we discuss the potential for using DR methodologies in this kind of meetings.  相似文献   
2.
The Fusion program, a method for agile, flexible computer integrated manufacturing (CIM) at Motorola's Paging Products Group, is discussed. Fusion's CIM and automated assembly system can manufacture a wide variety of different products on the same production line. The development of the Fusion program and how it differs from its predecessor, the Bandit program, are described  相似文献   
3.
This paper is dedicated to the determination of topological S parameters in the transmission line networks. We are especially interested in ideal junctions which consist of short circuit connections. For this type of junctions, it is impossible to deduce the S parameters from the usual impedance or admittance matrices which are not defined in this case. We suggest a method allowing a direct calculation of S. This procedure is described and then carried out for a two wire fork. At last, an experimental application is given for this model.  相似文献   
4.
Cytochromes P450 2B metabolize a variety of compounds and have provided an excellent framework for identifying determinants of substrate specificity. Among the rat 2B enzymes, a puzzling difference has emerged between the reported substrate specificity of purified hepatic 2B2 and that of certain 2B1 mutants containing 2B1 --> 2B2 substitutions. To address these discrepancies, we have characterized two 2B2 variants. A cDNA clone designated 2B2FF was obtained from phenobarbital-induced Lewis rats and, like some previously isolated variants, was found to contain phenylalanine at positions 58 and 114. A second 2B2 clone was generated by restoring Leu and Ile, respectively, at these positions. These enzymes were expressed in Escherichia coli and analyzed with androstenedione, testosterone, progesterone, ethoxycoumarin, benzyloxyresorufin, and pentoxyresorufin. The expressed 2B2 variants metabolized most substrates at rates that were 1-9% of those of 2B1. When steroid regio- and stereospecificity was examined, the metabolite profiles of expressed 2B2 and 2B2FF conflicted with the 16beta- and 16alpha-hydroxylation observed for purified hepatic 2B2 from Sprague-Dawley rats. These and other results suggested that the purified hepatic 2B2 contained a small percent of the 2B1 enzyme. Masses of tryptic peptides were consistent with identity between purified hepatic 2B2 and 2B2FF. On the basis of a three-dimensional homology model and the construction and analysis of 2B2 mutants, residues 114, 363, 367, and 478 were identified as determinants of substrate specificity. In addition, 2B1 and the expressed 2B2 variants showed differential susceptibility to the mechanism-based inactivators chloramphenicol and N-(2-p-nitrophenethyl)chlorofluoroacetamide.  相似文献   
5.
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   
6.
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   
7.
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   
8.
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   
9.
10.
An ecto-ATP diphosphohydrolase (ATPDase) was purified to homogeneity from vesiculosomes shed from chicken oviduct. First, the ecto-ATPDase-enriched vesiculosomes were concentrated by filtration, differential centrifugation, and exclusion chromatography. Next, the nonionic detergent, Nonidet P-40, was used to extract the ecto-ATPDase from vesiculosomal membranes, and the solubilized enzyme was further purified by ion exchange (DEAE-Bio-Gel) and lentil-lectin-Sepharose 4B chromatography. In the final stage, immunoaffinity chromatography was utilized to obtain purified ecto-ATPDase. More than 25,000-fold purification was achieved. Specific activity of the purified enzyme was greater than 800 micronol/min/mg of protein with MgATP as the substrate, the highest ever reported for an ATPDase. The enzyme also hydrolyzed other nucleoside triphosphates in the presence of magnesium at similar rates and CaATP and MgADP at lower rates. The molecular mass of the purified glycoprotein was 80 kDa as determined by SDS-polyacrylamide gel electrophoresis and Western blot analysis. Based on its enzymatic properties, the relationship of the chicken oviduct ecto-ATPDase with other reported ATPDases and ecto-ATPases is discussed.  相似文献   
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