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Sophie Frasnedo Gilles Duc Cédric Chapuis Philippe Feyel 《International journal of systems science》2019,50(1):8-22
The inertial stabilisation of the line of sight of an imager fixed on a mobile carrier is considered in order to acquire good quality images despite the disturbances generated by the carrier. A double stage mechanical stabilisation architecture is proposed, where a second stabilisation stage, based on a piezoelectric actuator, is added to the usual structure. The piezoelectric actuator transfer function and hysteresis are characterised through experiments. In order to design the controllers of both stages, a high-level image quality criterion (the modulation transfer function (MTF)) is considered, together with design constraints on the main variables of interest. The criterion and the constraints are evaluated by realistic simulations based on some input and noise profiles measured on a real-life system. The MTF evaluation being time-consuming, a Bayesian optimisation method specially dedicated to expensive-to-evaluate functions is used to obtain the parameters of the controllers. The obtain experimental results are displayed and their performances discussed. 相似文献
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In this paper, we illustrate specific power savings obtained from exploiting a reconfigurable mobile terminal under the 3GPP LTE standard. Building on traditional link adaptation towards maximum throughput and extended towards minimal power consumption, we add two flexible baseband components: the turbo decoder and the multiple input multiple output (MIMO) detector. Optimizing their configuration leads to larger power savings when compared to non-flexible systems only performing link adaptation. The gain observed strongly depends on the scenario. For low-activity set-ups with a few minutes of voice per day, the idle power dominates and the active data rate is relatively low. This makes analog front-end and time-domain processing dominant given their constant power consumption while MIMO detection and turbo decoding that scale with data rate play a smaller role. Still, because of its ability to improve the system spectral efficiency and hence reduce its duty cycle, an advanced MIMO detector can save 10% in power consumption, on the condition that the network requires to use MIMO. Otherwise single input single output is more power-efficient in downlink. In high-throughput scenarios, larger gains are obtained. The flexible MIMO detector can save up to 35% of average power consumption. The turbo decoding also brings some gain, saving up to 12% of power when the full bandwidth is allocated to a single user. 相似文献
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Damien Steyer Claude Erny Patricia Claudel Geneviève Riveill Francis Karst Jean-Luc Legras 《Food microbiology》2013
Geraniol produced by grape is the main precursor of terpenols which play a key role in the floral aroma of white wines. We investigated the fate of geraniol during wine fermentation by Saccharomyces cerevisiae. The volatile compounds produced during fermentation of a medium enriched with geraniol were extracted by Stir-bar sorptive extraction and analysed by GC–MS. We were able to detect and quantify geranyl acetate but also citronellyl- and neryl-acetate. The presence of these compounds partly explains the disparition of geraniol. The amounts of terpenyl esters are strain dependant. We demonstrated both by gene overexpression and gene-deletion the involvement of ATF1 enzyme but not ATF2 in the acetylation of terpenols. The affinity of ATF1 enzyme for several terpenols and for isoamyl alcohol was compared. We also demonstrated that OYE2 is the enzyme involved in geraniol to citronellol reduction. Fermenting strain deleted from OYE2 gene produces far less citronellol than wild type strain. Moreover lab strain over-expressing OYE2 allows 87% geraniol to citronellol reduction in bioconversion experiment compared to about 50% conversion with control strain. 相似文献
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Philippe Nika Yannick Bailly Michel De Labachelerie Jean Claude Jeannot Jacques De Lallee 《Nanoscale and Microscale Thermophysical Engineering》2013,17(4):301-325
The miniaturization of refrigerating systems represents a very current scientific and technical challenge to improve the performances of numerous electronic components. This work presents a global approach to the problem and suggests studying the cooling by means of small channels filled with an oscillating gas: the double inlet pulse tube refrigerator (DIPTR). A great level of miniaturization based on the technology of carving silicon is exposed. This study proposes to apply an electric analogy for modeling both hydrodynamic and thermal phenomena. Considering the complexity of the theoretical problem including mechanical, thermal, thermodynamical, and acoustic considerations, the authors take care to summarize the main governing equations in a particular form so any scientific engineer could understand the DIPTR principle. 相似文献
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Bulky End‐Capped [1]Benzothieno[3,2‐b]benzothiophenes: Reaching High‐Mobility Organic Semiconductors by Fine Tuning of the Crystalline Solid‐State Order 下载免费PDF全文
Guillaume Schweicher Vincent Lemaur Claude Niebel Christian Ruzié Ying Diao Osamu Goto Wen‐Ya Lee Yeongin Kim Jean‐Baptiste Arlin Jolanta Karpinska Alan R. Kennedy Sean R. Parkin Yoann Olivier Stefan C. B. Mannsfeld Jérôme Cornil Yves H. Geerts Zhenan Bao 《Advanced materials (Deerfield Beach, Fla.)》2015,27(19):3066-3072