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51.
This study reports a green and powerful strategy for preparing cellulose nanocrystal (CNC)/graphene oxide (GO)/natural rubber (NR) nanocomposites hosting a 3D hierarchical conductive network. Due to good dispersibility and amphiphilic nature of CNC, well dispersed CNC/GO nanohybrids were prepared. Hydrogen bonding interactions between CNC and GO greatly enhanced the stability of the CNC/GO nanohybrids. CNC/GO nanohybrids were introduced into NR latex under sonication and the mixture was cast. Self-assembled CNC/GO nanohybrids preferentially dispersed in the interstice between latex microspheres allowing the construction of a 3D hierarchical conductive network. By combining strong hydrogen bonds and 3D conductive network, both electrical conductivity and mechanical properties (tensile strength and modulus) have been significantly improved. The electrical conductivity of the nanocomposite with 4 wt% GO and 5 wt% CNC exhibited an increase of nine orders of magnitude compared to the nanocomposite with only 4 wt% GO; meanwhile, the electrical percolation threshold was 3-fold lower than for NR/GO composites. 相似文献
52.
The focus of this article is to develop mathematical morphology on hypergraphs. To this aim, we define lattice structures on hypergraphs on which we build mathematical morphology operators. We show some relations between these operators and the hypergraph structure, considering in particular transversals and duality notions. Then, as another contribution, we show how mathematical morphology can be used for classification or matching problems on data represented by hypergraphs: thanks to dilation operators, we define a similarity measure between hypergraphs, and we show that it is a kernel. A distance is finally introduced using this similarity notion. 相似文献
53.
Annals of Telecommunications - Le partage du risque est une des raisons les plus souvent avancées pour expliquer les clauses financières des contrats de licence. Pour autant, aucune... 相似文献
54.
Letf: {0,1}
n
{0,1}
m
be anm-output Boolean function inn variables.f is called ak-slice iff(x) equals the all-zero vector for allx with Hamming weight less thank andf(x) equals the all-one vector for allx with Hamming weight more thank. Wegener showed that PI
k
-set circuits (set circuits over prime implicants of lengthk) are at the heart of any optimum Boolean circuit for ak-slicef. We prove that, in PI
k
-set circuits, savings are possible for the mass production of anyFX, i.e., any collectionF ofm output-sets given any collectionX ofn input-sets, if their PI
k
-set complexity satisfiesSC
m
(FX)3n+2m. This PI
k
mass production, which can be used in monotone circuits for slice functions, is then exploited in different ways to obtain a monotone circuit of complexity 3n+o(n) for the Neiporuk slice, thus disproving a conjecture by Wegener that this slice has monotone complexity (n
3/2). Finally, the new circuit for the Neiporuk slice is proven to be asymptotically optimal, not only with respect to monotone complexity, but also with respect to combinational complexity. 相似文献
55.
Ibrahima Ka Ivy M. Asuo Suchismita Basu Paul Fourmont Dawit M. Gedamu Alain Pignolet Sylvain G. Cloutier Riad Nechache 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(38)
The morphology of hybrid organic–inorganic perovskite films is known to strongly affect the performance of perovskite‐based solar cells. CH3NH3PbI3‐xClx (MAPbI3‐xClx) films have been previously fabricated with 100% surface coverage in glove boxes. In ambient air, fabrication generally relies on solvent engineering to obtain compact films. In contrast, this work explores the potential of altering the perovskites microstructure for solar cell engineering. This work starts with CH3NH3PbI3‐xClx, films with grain morphology carefully controlled by varying the deposition speed during the spin‐coating process to fabricate efficient and partially transparent solar cells. Devices produced with a CH3NH3PbI3‐xClx film and a compact thick top gold electrode reach a maximum efficiency of 10.2% but display a large photocurrent hysteresis. As it is demonstrated, the introduction of different concentrations of bromide in the precursor solution addresses the hysteresis issues and turns the film morphology into a partially transparent interconnected network of 1D microstructures. This approach leads to semitransparent solar cells with negligible hysteresis and efficiencies up to 7.2%, while allowing average transmission of 17% across the visible spectrum. This work demonstrates that the optimization of the perovskites composition can mitigate the hysteresis effects commonly attributed to the charge trapping within the perovskite film. 相似文献
56.
The effects of numerical viscosity, subgrid scale (SGS) viscosity and grid resolution are investigated in LES and VMS-LES simulations of the flow around a circular cylinder at Re=3900 on unstructured grids. The separation between the largest and the smallest resolved scales in the VMS formulation is obtained through a variational projection operator and finite-volume cell agglomeration. Three different non-dynamic eddy-viscosity SGS models are used both in classical and in VMS-LES. The so-called small-small formulation is used in VMS-LES, i.e. the SGS viscosity is computed as a function of the smallest resolved scales. Two different grid resolutions are considered. It is found that, for each considered SGS model, the amount of SGS viscosity introduced in the VMS-LES formulation is significantly lower than in classical LES. This, together with the fact that in the VMS formulation the SGS viscosity only acts on the smallest resolved scales, has a strong impact on the results. However, a significant sensitivity of the results to the considered SGS model remains also in the VMS-LES formulation. Moreover, passing from classical LES to VMS-LES does not systematically lead to an improvement of the quality of the numerical predictions. 相似文献
57.
Abstract: Enterprise production is becoming more and more knowledge oriented nowadays and knowledge management is playing a key role in making commercial profit and maintaining enterprise competence. Knowledge characterization and measurement are the bases of knowledge management, and this paper aims to develop a method for characterizing and measuring knowledge in a comprehensive and practical way. Knowledge in its static state is modelled as a vector, whose values vary with the situation, and changes in state are modelled as a finite state machine. 相似文献
58.
Claudia Archetti Dominique Feillet Alain Hertz M. Grazia Speranza 《Computers & Operations Research》2010,37(11):1860-1869
A profit and a demand are associated with each edge of a set of profitable edges of a given graph. A travel time is associated with each edge of the graph. A fleet of capacitated vehicles is given to serve the profitable edges. A maximum duration of the route of each vehicle is also given. The profit of an edge can be collected by one vehicle only that also serves the demand of the edge. The objective of this problem, which is called the undirected capacitated arc routing problem with profits (UCARPP), is to find a set of routes that satisfy the constraints on the duration of the route and on the capacity of the vehicle and maximize the total collected profit. We propose a branch-and-price algorithm and several heuristics. We can solve exactly instances with up to 97 profitable edges. The best heuristics find the optimal solution on most of instances where it is available. 相似文献
59.
Wen Guang Qu Wonseok Oh Alain Pinsonneault 《The Journal of Strategic Information Systems》2010,19(2):96-108
Although research on the business impact of IT outsourcing abounds, little is known about the relative strategic value of IT outsourcing and IT insourcing. Drawing upon the knowledge-based view of the firm, this study postulates that, compared with IT outsourcing, IT insourcing is more effective for developing IT-enabled business processes (IEBP), which subsequently lead to superior firm performance. Our analysis of the data from InformationWeek and Compustat shows that IT insourcing is positively associated with IEBP, while the relationship between IT outsourcing and IEBP is not statistically significant. We also find that IEBP have a significant influence on firm performance. Finally, the effect of IT sourcing mechanisms on IEBP and the effect of IEBP on firm performance are both moderated by the type of innovation related to IEBP. The results suggest that in order to improve their performance firms should consider IT an integral part of their strategic core and should be proactively involved in the internal development of IT resources. We conclude with managerial implications and directions for future research. 相似文献
60.
Jonathan Gaudreault Jean-Marc Frayret Alain Rousseau Sophie D’Amours 《Computers & Operations Research》2011
Many research initiatives carried out in production management consider process planning and operations scheduling as two separate and sequential functions. However, in certain contexts, the two functions must be better integrated. This is the case in divergent production systems with co-production (i.e. production of different products at the same time from a single product input) when alternative production processes are available. This paper studies such a context and focuses on the case of drying and finishing operations in a softwood lumber facility. The situation is addressed using a single model that simultaneously performs process planning and scheduling. We evaluate two alternative formulations. The first one is based on mixed integer programming (MIP) and the second on constraint programming (CP). We also propose a search procedure to improve the performance of the CP approach. Both approaches are compared with respect to their capacity to generate good solutions in short computation time. 相似文献