The application of high-capacity silicon anodes in lithium batteries is restricted by the significant volume changes that occur during electrochemical alloying and long-term galvanic segregation ...cycles. In this work, we proposed a gas-phase magnesiothermic reduction strategy to fabricate highly porous SiOx/nanoSi@C (0 < x < 2) composites. This approach diffused the evaporated magnesium atoms into the interior of the SiO2, preventing the fast self-propagating magnesium thermal reduction reaction only on the surface of the silicon oxide particles and regulating the distribution and relative content of SiOx and nanoSi in the active material network. Thus, the proposed approach formed a porous structure of silicon nanocrystals that were diffusely distributed in the silicon oxide matrix. For the as-prepared SiOx/nanoSi@C composites, the nano-Si component increased the reversible capacity of the composite, the porous SiOx matrix suppressed the volume expansion of crystalline silicon by generating Li2O and lithium silicate protective layers, and the carbon coatings further accommodated volume expansion and increased surface contact between the active material and the electrolyte. As a result, the 0.75SiOx/0.25nanoSi@C anode exhibited excellent electrochemical performance with a reversible capacity of 1067.92 mAh/g after 400 cycles at a current density of 1 A/g.
Display omitted
•Fabrication of SiOx/nanoSi@C via a gas-phase magnesium thermal reduction.•This strategy avoids the fast self-propagation only on the surface of silicon oxide.•Highly porous SiOx/nanoSi@C composites suppress the volume expansion of silicon.•SiOx/nanoSi@C anode exhibits excellent electrochemical performance.
Nanoscience and technology has introduced a new dimension to basic sciences and a range of technologies. Researchers from various scientific disciplines are aggressively getting involved in the ...relevant research as a parallel way to boost nanoscience competitiveness through academic research, and corporations are directing their R&D activities towards the exploration and exploitation of nanotech opportunities. For years, it has been said that innovation is achieved by breaking through the boundaries of existing technologies. This paper has argued how nanotechnology is driven by scientific research and in what way traditional disciplines are fused into this emerging area. We attempt to provide an empirical analysis of the dynamics of nanoscience fusion trajectories, which is typically a focused area in innovation studies. In this paper, we seek to understand the attributes that are likely to enable scientific disciplines to fuse into nanoscience through a combination of quantitative and qualitative search within nanotechnology systems of innovation (NanoSI). An insight of the similarity and disparity of fusion between Europe and Japan is also provided. Finally, we develop an integrative framework to explore the co-evolutionary nature of nanotech. The paper then tries to derive some implications that would be useful for science and technology policy makers as well as for researchers in traditional scientific disciplines.
U radu su predstavljene primjene suvremenih metoda kontrole, kao što su termovizijska i spektrofotometrijska analiza, u grafičkoj industriji. Suvremene metode kontrole primijenjene su pri ...istraživanju parametara diferenciranog nanosa boje na specifične podloge izložene toplotnim opterećenjima. Uzorci koji su rabljeni za istraživanje odštampani su Ink jet postupkom na digitalnom tiskarskom stroju Mimaki JV 22 koja koristi J-Eco Subly nano boje. U procesu tiska, rabljene su tri vrste podloga, pri čemu je za sve njih sastav materijala bio isti, ali su se razlikovale prema parametrima površinske mase i gustoće pletenja. Odgovarajuća test karta koja se sastojala od polja CMYK otiskana je s pet različitih nanosa boje. Ti uzorci su izloženi toplinskom djelovanju, pri čemu je polje toplinskog djelovanja mjereno termovizijskom kamerom. Uzorci su analizirani spektrofotometrijskim mjerenjima prije i poslije toplinskog djelovanja te je na osnovu tih podataka određena vrijednost razlike boje (ΔE76). Dobiveni rezultati su pokazali da povećanje broja nanosa boje, kao i odabir odgovarajuće podloge za štampu, može povećati eksploatacijske karakteristike otisaka.
Ispiranje zlata iz recentnih i starih nanosa rijeka i potoka, jedan je od najstarijih oblika rudarenja, koji seže u predmetalno doba razvoja civilizacije (bakar i željezo). Razlog treba tražiti u ...neposrednoj upotrebi zlata bez znanja složene tehnologije pridobivanja čistog metala. Separacija teških minerala u vodotocima odvija se jednostavnim prirodnim procesom odnošenjem lakših mineralnih frakcija vodenom strujom. Postupci ispiranja zlata, korišteni od čovjeka, nisu ništa drugo nego kopiranje prirodnog procesa, uz male domišljate varijacije priručnog alata. U radu je opisana kratka povijest zlatarstva na Dravi, te data temeljita analiza geološke geneze zlatnih nanosa i mineraloški sastav dravskog zlata.
U području Gornjeg Vakufa koje je izgrađeno od paleozoj-skih sedimenata i metariolita, autori su istražili 47 rudnih pojava geološkim i različitim geokemijskim metodama. Razlikuju: (a) aluvijalne, ...diluvijalne i fluvioglacijalne zlatonosne nanose: (b) epigenetske, hidrotermalne žice u silursko-devonskim Škri-Ijavcima i u gornjopermskim sedimentima te gotovo monomi-neralne baritne (± tetraedru) žice, breče i nepravilna tijela u srednjodevonskim vapnenjacima; (c) postkinematska meta-morf'ogena monomineralna kvarcna ležišta u škriljavcima. Hidrotermalna ležišta imaju niz zajedničkih karakteristika: isključivi smještaj u paleozoiku, epigenetski karakter, jednostavnu, monotonu paragenezu (barit ± siderit kao glavne ne-rudne minerale i Hg-tetraedrit kao dominantan rudni mineral), siderit karakteriziran s visokim CaO, MgO i niskim MnO, svi su tetraedriti s Hg, Au, Ag i Bi, barit sa srednjim 2.9 wt% SrS04. Studij stabilnih izotopa je dao: 34S= + 15.0‰ u baritu, - 10.l‰ u tetraedritu, 18O = -9.6‰ i l3C = -3.7‰ u sideritu. Mikrotermometrijska mjerenja dala su:Th= +200 ºC u baritu. Vrlo bliska sličnost svih gore navedenih parametara s onima nađenim u ležištima Kreševa utjecala je na autore da pripi-šu rudnim ležištima područja Gornjeg Vakufa post-variscijski karakter postanka.
We developed InSpIon system capable of stable nanoESI spray. Here, K562 cell digests were measured by DDA-MS and DIA-MS with a typical open nanoESI spray system and a spray system inserted spray tip ...head into an ion transfer tube, and InSpIon system.
La croissance continue des besoins en puissance de calcul a conduit au triomphe du modèle de Cloud Computing. Des clients demandeurs en puissance de calcul vont s’approvisionner auprès de ...fournisseurs d’infrastructures de Cloud Computing, mises à disposition via Internet. Pour réaliser des économies d’échelles, ces infrastructures sont toujours plus grandes et concentrées en quelques endroits, conduisant à des problèmes tels que l’approvisionnement en énergie, la tolérance aux pannes et l’éloignement des utilisateurs. Cette thèse s’est intéressée à la mise en place d’un système d’IaaS massivement distribué et décentralisé exploitant un réseau de micros centres de données déployés sur la dorsale Internet, utilisant une version d’OpenStack revisitée pendant cette thèse autour du support non intrusif de bases de données non relationnelles. Des expériences sur Grid’5000 ont montré des résultats intéressants sur le plan des performances, toutefois limités par le fait qu’OpenStack ne tirait pas avantage nativement d’un fonctionnement géographiquement réparti. Nous avons étudié la prise en compte de la localité réseau pour améliorer les performances des services distribués en favorisant les collaborations proches. Un prototype de l’algorithme de placement de machines virtuelles DVMS, fonctionnant sur une topologie non structurée basée sur l’algorithme Vivaldi, a été validé sur Grid’5000. Ce prototype a fait l’objet d’un prix scientifique lors de l’école de printemps Grid’50002014. Enfin, ces travaux nous ont amenés à participer au développement du simulateur VMPlaceS.
The continuous increase of computing power needs has favored the triumph of the Cloud Computing model. Customers asking for computing power will receive supplies via Internet resources hosted by providers of Cloud Computing infrastructures. To make economies of scale, Cloud Computing that are increasingly large and concentrated in few attractive places, leading to problems such energy supply, fault tolerance and the fact that these infrastructures are far from most of their end users. During this thesis we studied the implementation of an fully distributed and decentralized IaaS system operating a network of micros data-centers deployed in the Internet backbone, using a modified version of OpenStack that leverages non relational databases. A prototype has been experimentally validated onGrid’5000, showing interesting results, however limited by the fact that OpenStack doesn’t take advantage of a geographically distributed functioning. Thus, we focused on adding the support of network locality to improve performance of Cloud Computing services by favoring collaborations between close nodes. A prototype of the DVMS algorithm, working with an unstructured topology based on the Vivaldi algorithm, has been validated on Grid’5000. This prototype got the first prize at the large scale challenge of the Grid’5000 spring school in 2014. Finally, the work made with DVMS enabled us to participate at the development of the VMPlaceS simulator.
PDF
