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排序方式: 共有134条查询结果,搜索用时 15 毫秒
71.
Niranjan Reddy Challabotla Lihao Zhao Helge I. Andersson 《Flow, Turbulence and Combustion》2016,97(4):1095-1110
The present study investigated gravity effects on the dynamical behavior of inertial fibers suspended in a vertical channel flow. Direct numerical simulations were performed to obtain the turbulent flow field and the fibers were modelled as prolate spheroidal point particles. For each of the four fiber classes, three different gravity configurations were considered: upward flow with gravity opposing, downward flow with aiding gravity, and channel flow in absence of gravity. Results for the fiber distribution and the translational and rotational fiber motion were reported. In the near-wall region, the presence of gravity resulted in an increased fiber density in the downward flow but a nearly uniform distribution of fibers in upward flow. However, the preferential clustering of fibers in near-wall low-speed streaks was unaffected by gravity. The mean wall-normal or drift velocity of the fibers was higher in the downward flow and lower in the upward flow as compared to the case with no gravity. The suppressed drift velocity in the upward flow resulted in a more uniform fiber distribution throughout the channel in contrast to the near-wall accumulation of fibers in the two other cases. Overall gravity turned out to have negligible effects on some of the statistics of the least inertial fibers whereas the inclusion of gravity had a strong impact for heavier fibers. 相似文献
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Mst Nasima Khatun Arvin Sain Tanwar Niranjan Meher Parameswar Krishnan Iyer 《化学:亚洲杂志》2019,14(24):4725-4731
The development of a new naphthalene appended naphthalimide derivative ( NMI ) with aggregation‐induced enhanced emission (AIEE) property for the sensitive detection of 4‐nitroaniline (4‐NA) in aqueous media is presented here. The newly designed naphthalimide AIEEgen has an exceptional blue‐shifted condensed state emission that is devoid of any receptor site, accomplished ultrasensitive detection of 4‐NA, which is one of the broad‐spectrum pesticides that belong to the class III toxic chemical, at parts per billion level (LOD/36 ppb, Ksv=4.1×104 m ?1) in water with excellent selectivity even in the presence of potentially competing aliphatic and aromatic amines. The reported probe is the first of its kind, demonstrating major advantages of receptor‐free inner filter effect (IFE) mechanism for the sensitive detection of 4‐NA using an AIEEgenic probe. Excellent sensitivity for 4‐NA is also achieved on paper‐based test‐strip for low‐cost on‐site detection. 相似文献
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To study the effect of nanofiller particle TiO2 on sodium (Na+) – ion conducting solid polymer electrolyte (SPE) film: [80PEO:20NaPF6] and nanocomposite polymer electrolyte (NCPE): [80PEO:20NaPF6] + xTiO2, where x = 1–9 wt. (%) have been prepared. SPE film composition: [80PEO:20NaPF6] selects as Ist-phase host and nano-sized (<100 nm) filler materials TiO2 as IInd-phase dispersoid. Both SPE and NCPE films have been prepared by the hot-press technique. Filler particle-dependent conductivity study reveals the NCPE system: [80PEO:20NaPF6] + 8TiO2 as the highest conducting composition with σrt − 3.53 × 10−6 S cm−1, which is approximately one order of magnitude higher than the SPE optimum conducting composition (OCC) (σrt) ≈ 7.78 × 10−7 S cm−1. Ion transport properties for both SPE and NCPE system have been evaluated in terms of ionic conductivity (σ) and total ionic (tion)/cationic (t+) transference numbers using combined AC/DC techniques in order to evaluate its usefulness in all-solid-state battery applications. Structural/thermal properties have been characterized using X-ray diffraction (XRD) and differential scanning calorimetry (DSC) techniques. A cyclic voltammetry (CV) study has been performed in SPE and NCPE OCC film to evaluate the electrochemical performance for battery application. 相似文献
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In solving challenging pattern recognition problems, deep neural networks have shown excellent performance by forming powerful mappings between inputs and targets, learning representations (features) and making subsequent predictions. A recent tool to help understand how representations are formed is based on observing the dynamics of learning on an information plane using mutual information, linking the input to the representation () and the representation to the target (). In this paper, we use an information theoretical approach to understand how Cascade Learning (CL), a method to train deep neural networks layer-by-layer, learns representations, as CL has shown comparable results while saving computation and memory costs. We observe that performance is not linked to information–compression, which differs from observation on End-to-End (E2E) learning. Additionally, CL can inherit information about targets, and gradually specialise extracted features layer-by-layer. We evaluate this effect by proposing an information transition ratio, , and show that it can serve as a useful heuristic in setting the depth of a neural network that achieves satisfactory accuracy of classification. 相似文献
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79.
Niranjan Panda Ashis Kumar JenaSasmita Mohapatra Smruti Ranjan Rout 《Tetrahedron letters》2011,52(16):1924-1927
The synergistic effects of iron and copper in copper ferrite nanoparticles for the N-arylation of heterocycles with aryl halides were demonstrated. The magnetic nature of the catalyst facilitates its removal from the reaction medium for further use. Negligible leaching of Cu and Fe in consecutive cycles makes the catalyst economical and environmentally benign for C-N cross-coupling reactions. 相似文献
80.
We present an ab-initio study of structural, electronic and ferroic properties of lead-free orthorhombic AgNbO3 in centrosymmetric Pbcm and recently proposed noncentrosymmetric Pmc21 space group symmetries. The calculated polarization of AgNbO3 in Pmc21 phase is ~0.09 μC/cm2, whereas it is 55.9 μC/cm2 in the ideal cubic phase. The large polarization of AgNbO3 in the ideal cubic structure is attributed to off-centering of Ag as well as Nb ions at the A and B sites, respectively. In our calculations both phases (Pmc21 and Pbcm) of AgNbO3 show small relative energy difference (~0.1 meV/f.u), thus suggesting the coexistence of centrosymmetric and non-centrosymmetric phases and thereby antiferroelectric and ferroelctric order in room temperature AgNbO3 polycrystals. We further study structural properties and spontaneous polarization in orthorhombic Pmc21 Ag1?xKxNbO3 solid solutions. The calculated spontaneous polarization of AgNbO3 is enhanced due to suppression of NbO6 octahedral tilt angles as K ion is substituted at Ag sites. Our study suggests that appropriate cation substitution should indeed result in the improvement of ferroelectric properties of lead-free AgNbO3. 相似文献