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排序方式: 共有1398条查询结果,搜索用时 15 毫秒
1.
N. Jongen M. Donnet P. Bowen J. Lemaître H. Hofmann R. Schenk C. Hofmann M. Aoun‐Habbache S. Guillemet‐Fritsch J. Sarrias A. Rousset M. Viviani M.T. Buscaglia V. Buscaglia P. Nanni A. Testino J.R. Herguijuela 《化学工程与技术》2003,26(3):303-305
The synthesis of powders with controlled shape and narrow particle size distributions is still a major challenge for many industries. A continuous Segmented Flow Tubular Reactor (SFTR) has been developed to overcome homogeneity and scale‐up problems encountered when using batch reactors. Supersaturation is created by mixing the co‐reactants in a micromixer inducing precipitation; the suspension is then segmented into identical micro‐volumes by a non‐miscible fluid and sent through a tube. These micro‐volumes are more homogeneous when compared to large batch reactors leading to narrower size distributions, better particle morphology, polymorph selectivity and stoichiometry. All these features have been demonstrated on single tube SFTR for different chemical systems. To increase productivity for commercial application the SFTR is being “scaled‐out” by multiplying the number of tubes running in parallel instead of scaling‐up by increasing their size. The versatility of the multi‐tube unit will allow changes in type of precipitate with a minimum of new investment as new chemistry can be researched, developed and optimised in a single tube SFTR and then transferred to the multi‐tube unit for powder production. 相似文献
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A system for person-independent classification of hand postures against complex backgrounds in video images is presented. The system employs elastic graph matching, which has already been successfully applied for object and face recognition. We use the bunch graph technique to model variance in hand posture appearance between different subjects and variance in backgrounds. Our system does not need a separate segmentation stage but closely integrates finding the object boundaries with posture classification. 相似文献
4.
Peak-to-average power reduction in space division multiplexing based OFDM systems through spatial shifting 总被引:2,自引:0,他引:2
A new method to reduce the peak-to-average power ratio (PAPR) in space division multiplexing systems applying orthogonal frequency division multiplexing is proposed. The method applies spatial shifting to partial transmit sequences to achieve a decreased PAPR on all transmit branches. 相似文献
5.
Matthias Zobel Joachim Denzler Benno Heigl Elmar Nöth Dietrich Paulus Jochen Schmidt Georg Stemmer 《Machine Vision and Applications》2003,14(1):26-34
Abstract. This contribution introduces MOBSY, a fully integrated, autonomous mobile service robot system. It acts as an automatic dialogue-based
receptionist for visitors to our institute. MOBSY incorporates many techniques from different research areas into one working
stand-alone system. The techniques involved range from computer vision over speech understanding to classical robotics.
Along with the two main aspects of vision and speech, we also focus on the integration aspect, both on the methodological
and on the technical level. We describe the task and the techniques involved. Finally, we discuss the experiences that we
gained with MOBSY during a live performance at our institute. 相似文献
6.
It is well recognized that performance changes over time. However, the effect of these changes on overall assessments of performance is largely unknown. In a laboratory experiment, we examined the influence of salient Gestalt characteristics of a dynamic performance profile on supervisory ratings. We manipulated performance trend (flat, linear-improving, linear-deteriorating, U-shaped, and ∩-shaped), performance variation (small, large), and performance mean (negative, zero, positive) within subjects and display format (graphic, tabular) between subjects. Participants received and evaluated information about the weekly performance of different employees over a simulated 26-week period. Results showed strong main effects on performance ratings of both performance mean and performance trend, as well as interactions with display format. Theoretical and practical implications of the results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
Awareness of the construction environment can be improved by automatic three-dimensional (3D) sensing and modeling of job sites in real time. Commercially available 3D modeling approaches based on range scanning techniques are capable of modeling static objects only, and thus cannot model dynamic objects in real time in an environment comprised of moving humans, equipment, and materials. Emerging prototype video range cameras offer an alternative by facilitating affordable, wide field of view, dynamic object tracking at frame rates better than 1?Hz (real time). This paper describes a methodology to model, detect, and track the position of static and moving objects in real time, based on data obtained from video range cameras. Experiments with this technology have produced results that indicate that video rate 3D data acquisition and analysis of construction environments can support effective modeling, detection, and tracking of project resources. This approach to job site awareness has inherent value and broad application. In combination with effective management practices and other sensing techniques, this technology has the potential to significantly improve safety on construction job sites. 相似文献
8.
H Riemer R Hainz C Stain G Dekan M Feldner-Busztin P Schenk C Müller K Sertl OC Burghuber 《Canadian Metallurgical Quarterly》1997,52(11):1014-1015
The case is described of a 58 year old man with systemic Whipple's disease with pericardial and pleural effusions and severe pulmonary hypertension. After three months of antibiotic treatment there was a complete resolution, not only of the symptoms known to be associated with Whipple's disease (diarrhoea, arthralgia, pericardial and pleural effusions), but also of pulmonary hypertension. 相似文献
9.
In-Situ and Real-Time Investigation of Columnar-to-Equiaxed Transition in Metallic Alloy 总被引:1,自引:0,他引:1
H. Nguyen-Thi G. Reinhart N. Mangelinck-Noël H. Jung B. Billia T. Schenk J. Gastaldi J. Härtwig J. Baruchel 《Metallurgical and Materials Transactions A》2007,38(7):1458-1464
In this article, we present a review of observations during Al-3.5 wt pct Ni alloy solidi.cation experiments performed at
the European Synchrotron Radiation Facility (ESRF) in Grenoble. These experiments provide direct access to dynamical phenomena
during columnar growth (initial transient and breakdown of a planar solid-liquid interface), and for the first time to the
transition from columnar-to-equiaxed microstructure (nucleation ahead of a columnar front and blocking of a columnar front
by an equiaxed microstructure) and fully equiaxed growth (propagation of an effective front). Based on these experimental
observations, critical parameters such as columnar growth velocity variation during the transition or equiaxed-grain diameter
are measured and discussed.
This article is based on a presentation made in the symposium entitled “Solidi.cation Modeling and Microstructure Formation:
In Honor of Prof. John Hunt,” which occurred March 13–15, 2006, during the TMS Spring Meeting in San Antonio, Texas, under
the auspices of the TMS Materials Processing and Manufacturing Division, Solidification Committee. 相似文献
10.