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排序方式: 共有1395条查询结果,搜索用时 15 毫秒
61.
Hugo Serra João Pedro Oliveira Nuno Paulino 《International Journal of Circuit Theory and Applications》2020,48(11):1922-1941
This paper presents an overview of design techniques to reduce the capacitance spread of SC notch filters. Three of these techniques are used in the design of a 50-Hz notch filter, intended for an internet of things (IoT) water management sensor node. In this application, due to the high sampling frequency required by the acquisition channel's ADC, the filter's Fs/fp ratio becomes excessively large, resulting in a capacitance spread of 3225.8, if a conventional SC implementation is used. Using charge division networks, with up to seven share/reset cycles, the filter's capacitance spread is reduced by a factor 12.9 and the total capacitance by 5.9, and a total power dissipation of approximately 262 μ W, for a supply voltage of 0.9 V. Using capacitive T-cell networks, the filter's capacitance spread is reduced by a factor 40.5 and the total capacitance by 14.2. Using partial charge transfer networks, the filter's capacitance spread is improved by a factor 41.6, and the total capacitance by 10.0. The filter's total power consumption, using the last two techniques, is approximately 11 μ W. 相似文献
62.
Knowledge transfer offices (KTOs) are required to adopt a comprehensive approach to managing a broad set of channels of university–industry collaboration, including collaborative research, business services, exchange of human resources and informal relations within a regional innovation system. The perspectives of firms and academic researchers, the main stakeholders of KTOs, are useful complements to assess KTO activity. The goal of this article is to study the effectiveness that these stakeholders attribute to KTOs. Based on survey data collected in the Spanish region of Andalusia, the article explores stakeholders’ perceptions and determinants. The results show that the level of engagement in a diversified range of activities and the importance attributed to knowledge transfer in the strategy of both research groups and firms are the best predictors of the perceived effectiveness of KTOs. The article also underlines specific differences between the two types of stakeholders. 相似文献
63.
Nutritional studies are greatly hampered by a paucity of proper models. Previous studies on nutrition have employed conventional cell lines and animal models to gain a better understanding of the field. These models lack certain correlations with human physiological responses, which impede their applications in this field. Enteroids are cultured from intestinal stem cells and include enterocytes, enteroendocrine cells, goblet cells, Paneth cells, and stem cells, which mimic hallmarks of in vivo epithelium and support long‐term culture without genetic or physiological changes. Enteroids have been used as models to study the effects of diet and nutrients on intestinal growth and development, ion and nutrient transport, secretory and absorption functions, the intestinal barrier, and location‐specific functions of the intestine. In this review, the existing models for nutritional studies are discussed and the importance of enteroids as a new model for nutritional studies is highlighted. Taken together, it is suggested that enteroids can serve as a potential model system to be exploited in nutritional studies. 相似文献
64.
Hugo Uvegi Piyush Chaunsali Brian Traynor Elsa Olivetti 《Journal of the American Ceramic Society》2019,102(12):7678-7688
An untapped source of amorphous SiO2, industrially generated Indian biomass ash (SA)—90% amorphous, with composition of ~60% SiO2 and ~20% unburnt carbon—can be used to produce cementitious and alkali-activated binders. This study reports dissolution of amorphous Si from SA in 0.5 mol/L and 1 mol/L aqueous NaOH, with and without added Ca(OH)2, at SA:Ca(OH)2 wt% ratios of 100:0, 87.5:12.5, and 82.5:17.5. Monitoring of elemental dissolution and subsequent/simultaneous product uptake by ICP-OES offers an effective process for evaluating utility of industrial wastes in binder-based systems. After 28 days in solution, up to 68% of total Si is dissolved from SA in 1 mol/L NaOH, with values as much as 38% lower in the presence of Ca(OH)2, due to the formation of tobermorite-like C-S-H. FTIR, 29Si MAS-NMR, and XRD are used to characterize solid reaction products and observe reaction progress. Product chemistries calculated from ICP-OES results and verified by selective dissolution in EDTA/NaOH—namely, Ca/Si of 0.6-1 and Na adsorption of 1-2 mmol/g—are found to be consistent with those indicated by aforementioned techniques. This indicates the efficacy of ICP-OES in estimating product chemistry via such a methodology. 相似文献
65.
Dr. Eduarda Mendes Enrico Cadoni Filipa Carneiro Dr. Marta B. Afonso Hugo Brito Dr. João Lavrado Dr. Daniel J. V. A. dos Santos Dr. Jorge B. Vítor Prof. Stephen Neidle Prof. Cecília M. P. Rodrigues Prof. Alexandra Paulo 《ChemMedChem》2019,14(14):1325-1328
Quadruplex nucleic acids are promising targets for cancer therapy. In this study we used a fragment-based approach to create new flexible G-quadruplex (G4) DNA-interactive small molecules with good calculated oral drug-like properties, based on quinoline and triazole heterocycles. G4 melting temperature and polymerase chain reaction (PCR)-stop assays showed that two of these compounds are selective G4 ligands, as they were able to induce and stabilize G4s in a dose- and DNA sequence-dependent manner. Molecular docking studies have suggested plausible quadruplex binding to both the G-quartet and groove, with the quinoline module playing the major role. Compounds were screened for cytotoxicity against four cancer cell lines, where 4,4′-(4,4′-(1,3-phenylene)bis(1H-1,2,3-triazole-4,1-diyl))bis(1-methylquinolin-1-ium) ( 1 d ) showed the greater activity. Importantly, dose–response curves show that 1 d is cytotoxic in the human colon cancer HT-29 cell line enriched in cancer stem-like cells, a subpopulation of cells implicated in chemoresistance. Overall, this study identified a new small molecule as a promising lead for the development of drugs targeting G4 in cancer stem cells. 相似文献
66.
Julie Lachaux Hugo Salmon Fanny Loisel Nassim Arouche Ignacio Ochoa Luis L. Fernandez Georges Uzan Olaf Mercier Teodor Veres Emmanuel Roy 《Advanced Materials Technologies》2019,4(2)
Spin‐coating process of a commercially available soft thermoplastic elastomer (sTPE) is demonstrated for the realization of microfluidic prototypes. It is a reliable, wrinkling‐free, and high‐yield holding and transfer methodology for single and multilayered devices fabrication. Complex microfluidic systems including embedded microlenses array, dilutor‐like chip for stable capillary filling, and pneumatically drive valve confirms the performances and quality of the process. The dissolved sTPE, a soft styrenic‐block polymer‐based material, is flexible in its raw state as poly(dimethylsiloxane) and thermoformable as classical thermoplastics. Depending on the solvent evaporation rate, two stable morphologies of the block nanodomains are revealed: either a nanocylinder or hexagonal nanospheres pattern. Both are evenly distributed over the whole surface and account for a uniform and convenient surface at a “microfluidic scale device.” Plasma hydrophilization allows a stable and hydrophilic surface (≈20° after 7 d). The biocompatibility is assessed through the cell culture proliferation assay of progenitor endothelial cells. This sTPE solution displays fast and reliable fabrication and assembly performances, it can achieve strong and stable hydrophilicity within a low level of initial equipment investment. 相似文献
67.
68.
Hugo Zanghi Author Vitae Christophe Ambroise Author Vitae 《Pattern recognition》2008,41(12):3592-3599
In the context of graph clustering, we consider the problem of simultaneously estimating both the partition of the graph nodes and the parameters of an underlying mixture of affiliation networks. In numerous applications the rapid increase of data size over time makes classical clustering algorithms too slow because of the high computational cost. In such situations online clustering algorithms are an efficient alternative to classical batch algorithms. We present an original online algorithm for graph clustering based on a Erd?s-Rényi graph mixture. The relevance of the algorithm is illustrated, using both simulated and real data sets. The real data set is a network extracted from the French political blogosphere and presents an interesting community organization. 相似文献
69.
Iris recognition has been widely used in several scenarios with very satisfactory results. As it is one of the earliest stages, the image segmentation is in the basis of the process and plays a crucial role in the success of the recognition task. In this paper we analyze the relationship between the accuracy of the iris segmentation process and the error rates of three typical iris recognition methods. We selected 5000 images of the UBIRIS, CASIA and ICE databases that the used segmentation algorithm can accurately segment and artificially simulated four types of segmentation inaccuracies. The obtained results allowed us to conclude about a strong relationship between translational segmentation inaccuracies – that lead to errors in phase – and the recognition error rates. 相似文献
70.
Sergej Alexandrovich Filonovich Hugo águas Tito Busani António Vicente Andreia Araújo Diana Gaspar Marcia Vilarigues Joaquim Leit?o Elvira Fortunato Rodrigo Martins 《Science and Technology of Advanced Materials》2012,13(4)
We have characterized the structure and electrical properties of p-type nanocrystalline silicon films prepared by radio-frequency plasma-enhanced chemical vapor deposition and explored optimization methods of such layers for potential applications in thin-film solar cells. Particular attention was paid to the characterization of very thin (∼20 nm) films. The cross-sectional morphology of the layers was studied by fitting the ellipsometry spectra using a multilayer model. The results suggest that the crystallization process in a high-pressure growth regime is mostly realized through a subsurface mechanism in the absence of the incubation layer at the substrate-film interface. Hydrogen plasma treatment of a 22-nm-thick film improved its electrical properties (conductivity increased more than ten times) owing to hydrogen insertion and Si structure rearrangements throughout the entire thickness of the film. 相似文献