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排序方式: 共有145条查询结果,搜索用时 15 毫秒
21.
AbstractThe well-known Jahn-Graef-Younes algorithm, proposed by Jahn in 2006, generates all minimal elements of a finite set with respect to an ordering cone. It consists of two Graef-Younes procedures, namely the forward iteration, which eliminates a part of the non-minimal elements, followed by the backward iteration, which is applied to the reduced set generated by the previous iteration. Without using the backward iteration, we develop new algorithms that also compute all minimal elements of the initial set, by combining the forward iteration with certain sorting procedures based on cone-monotone functions. In particular, when the ordering cone is polyhedral, computational results obtained in MATLAB allow us to compare our algorithms with the Jahn-Graef-Younes algorithm, within a bi-objective optimization problem. 相似文献
22.
Lucian Beznea Iulian Cîmpean Michael Röckner 《Stochastic Processes and their Applications》2018,128(4):1405-1437
We analyze the transience, recurrence, and irreducibility properties of general sub-Markovian resolvents of kernels and their duals, with respect to a fixed sub-invariant measure . We give a unifying characterization of the invariant functions, revealing the fact that an -integrable function is harmonic if and only if it is harmonic with respect to the weak dual resolvent. Our approach is based on potential theoretical techniques for resolvents in weak duality. We prove the equivalence between the -irreducible recurrence of the resolvent and the extremality of in the set of all invariant measures, and we apply this result to the extremality of Gibbs states. We also show that our results can be applied to non-symmetric Dirichlet forms, in general and in concrete situations. A second application is the extension of the so called Fukushima ergodic theorem for symmetric Dirichlet forms to the case of sub-Markovian resolvents of kernels. 相似文献
23.
S. Rout N. Popovici S. Dalui M.L. Paramês R.C. da Silva A.J. Silvestre O. Conde 《Current Applied Physics》2013,13(4):670-676
This paper reports on the structural and optical properties of Co-doped TiO2 thin films grown onto (0001)Al2O3 substrates by non-reactive pulsed laser deposition (PLD) using argon as buffer gas. It is shown that by keeping constant the substrate temperature at as low as 310 °C and varying only the background gas pressure between 7 Pa and 70 Pa, it is possible to grow either epitaxial rutile or pure anatase thin films, as well as films with a mixture of both polymorphs. The optical band gaps of the films are red shifted in comparison with the values usually reported for undoped TiO2, which is consistent with n-type doping of the TiO2 matrix. Such band gap red shift brings the absorption edge of the Co-doped TiO2 films into the visible region, which might favour their photocatalytic activity. Furthermore, the band gap red shift depends on the films’ phase composition, increasing with the increase of the Urbach energy for increasing rutile content. 相似文献
24.
Stan Stelian Chisamera Mihai Riposan Iulian Stefan Eduard Neacsu Loredana Cojocaru Ana Maria Stan Iuliana 《Journal of Thermal Analysis and Calorimetry》2019,138(4):2529-2540
Journal of Thermal Analysis and Calorimetry - Simultaneous thermal and contraction/expansion analysis of hypoeutectic grey (lamellar graphite) and ductile (nodular graphite) cast irons... 相似文献
25.
Stefan Eduard Riposan Iulian Chisamera Mihai 《Journal of Thermal Analysis and Calorimetry》2019,138(4):2491-2503
Journal of Thermal Analysis and Calorimetry - The new generation of acid-lined medium-frequency coreless induction furnaces revolutionized the iron foundries, resulting higher overheating and lower... 相似文献
26.
Popovici J Bertrand C Bagnarol E Fernandez MP Comte G 《Natural product research》2008,22(12):1024-1032
The essential oil and the volatile compounds of Myrica gale fruits were analysed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). The volatile compounds were detected using two different fibres for headspace-solid phase microextraction (HS-SPME), Carboxen/PDMS and PDMS. Sixty two compounds were identified, which represented more than 90% of the total extracts. Major components of fruit essential oil are alpha-pinene (22.6%), 1,8-cineole (18.9%) and germacrone (14.2%), whereas they are germacrone (25.1%), alpha-pinene (12.2%), limonene (8.1%) and alpha-phellandrene (8.0%) for the leaf essential oil. Major volatile fruit compounds detected in HS-SPME were alpha-pinene, 1,8-cineole, p-cymene and eth-cadinene. As M. gale fruits are traditionally used in brewery for flavouring beer or as a spice in soups or stews, the antifungal properties of these essential oils were investigated on a panel of foodborne fungi, namely Aspergillus flavus, Cladosporium cladosporioides and Penicillium expansum. A complete antifungal activity was observed at 1000 ppm against C. cladosporioides. Both essential oil and entire fruits could thus be used as an additive in food or cosmetic preparations for their flavour, odour and their conservative properties. 相似文献
27.
We prove that
||PX - XQ|| = max{||PX(1 - Q)||, ||(1 - P)XQ||}\|PX - XQ\| = {\rm max}\{\|PX(1 - Q)\|, \|(1 - P)XQ\|\} 相似文献
28.
Mihai Cosmin Corobea Oana Muhulet Florin Miculescu Iulian Vaile Antoniac Zina Vuluga Dorel Florea Dumitru Mircea Vuluga Maria Butnaru Daniela Ivanov Stefan Ioan Voicu Vijay Kumar Thakur 《先进技术聚合物》2016,27(12):1586-1595
In this study, a new class of heterogeneous membranes based on cellulose acetate (CA) polymer and a complex filler clay‐silica nanowires (SiO2NWs) was investigated for potential biomedical applications. SiO2NWs were synthesized using natural clay through a facile sol–gel method and were dispersed in the polymer solution by sonication in the 1.25, 2.5, and 5% weight ratio to the CA acetate polymer. Membranes were subsequently prepared via phase inversion by precipitation of the CA polymer in water. The pristine CA membrane and SiO2NWs based nanocomposites membranes were characterized using different characterization techniques. The presence of the SiO2NWs in the CA membrane was found to significantly enhance the protein retention, water wettability and thermal as well as mechanical properties in comparison to the pristine CA membrane. Water flows studies at different temperatures and the retention of bovine serum albumin have been studied and the nanocomposite membranes were found to exhibit superior performances compared with the pristine CA membranes. SiO2NWs‐CA membranes showed a much higher stability to the water temperature change during separation than CA membranes. Morphological changes clearly revealed that the composite membrane were much more compact than the pristine CA membranes. The rabbit dermal fibroblasts cell viability in cultures after 72 hr of incubation was found to be greater than 80%. These newly synthesized composite membranes exhibit a high potential to be used for various medical applications because of their non‐cytotoxic characteristics. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
29.
30.
I. Morjan I. Soare R. Alexandrescu R.-E. Morjan L. Gavrila-Florescu G. Prodan I. Sandu E. Popovici F. Dumitrache I. Voicu M. Scarisoreanu 《Physica E: Low-dimensional Systems and Nanostructures》2007,37(1-2):26
We report about the synthesis of carbon nanotubes by catalytic LCVD (C-LCVD), using a CW CO2 laser and alternatively, C2H2/C2H4/NH3 and C2H2/C2H4-containing gas mixtures. Different core–shell Fe–C nanocomposites (as synthesized and toluene extracted) were used employed as catalysts. The nanotubes grown from Fe–C residue demonstrate the lowest mean diameters. Prevalent curled and coiled morphologies are obtained for the CNTs grown in the presence of ammonia. 相似文献
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