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931.
932.
Rafael Cao Lucas Cortez Ismael de Farias Ernee Kozyreff Jalil Khatibi Moqadam Renato Portugal 《Entropy (Basel, Switzerland)》2021,23(10)
We study discrete-time quantum walks on generalized Birkhoff polytope graphs (GBPGs), which arise in the solution-set to certain transportation linear programming problems (TLPs). It is known that quantum walks mix at most quadratically faster than random walks on cycles, two-dimensional lattices, hypercubes, and bounded-degree graphs. In contrast, our numerical results show that it is possible to achieve a greater than quadratic quantum speedup for the mixing time on a subclass of GBPG (TLP with two consumers and m suppliers). We analyze two types of initial states. If the walker starts on a single node, the quantum mixing time does not depend on m, even though the graph diameter increases with it. To the best of our knowledge, this is the first example of its kind. If the walker is initially spread over a maximal clique, the quantum mixing time is , where ϵ is the threshold used in the mixing times. This result is better than the classical mixing time, which is . 相似文献
933.
Weslley Souza Paiva Francisco Ernesto de Souza Neto Moacir Fernandes Queiroz Lucas Alighieri Neves Costa Batista Hugo Alexandre Oliveira Rocha Anabelle Camarotti de Lima Batista 《Molecules (Basel, Switzerland)》2022,27(1)
Animal chitosan (Chit-A) is gaining more acceptance in daily activities. It is used in a range of products from food supplements for weight loss to even raw materials for producing nanoparticles and hydrogel drug carriers; however, it has low antioxidant activity. Fungal oligochitosan (OChit-F) was identified as a potential substitute for Chit-A. Cunninghamella elegans is a fungus found in the Brazilian savanna (Caatinga) that produces OligoChit-F, which is a relatively poorly studied compound. In this study, 4 kDa OChit-F with a 76% deacetylation degree was extracted from C. elegans. OChit-F showed antioxidant activity similar to that of Chit-A in only one in vitro test (copper chelation) but exhibited higher activity than that of Chit-A in three other tests (reducing power, hydroxyl radical scavenging, and iron chelation). These results indicate that OChit-F is a better antioxidant than Chit-A. In addition, Chit-A significantly increased the formation of calcium oxalate crystals in vitro, particularly those of the monohydrate (COM) type; however, OChit-F had no effect on this process in vitro. In summary, OChit-F had higher antioxidant activity than Chit-A and did not induce the formation of CaOx crystals. Thus, OChit-F can be used as a Chit-A substitute in applications affected by oxidative stress. 相似文献
934.
935.
In the present paper, we attempt to explain the macroscopic flow law evolution in porous media according to the Reynolds number.
A crenellated channel, considered as an element of such a medium, is used to perform numerical simulations in stationary and
non-stationary cases. In the case of non-stationary laminar flows, we point out flow instabilities occurring in the channel
at high Reynolds numbers and we focus on their influence on the macroscopic law. We qualitatively prove that they generate
an additional quadratic contribution to Forchheimer’s law. We use two methods to study this contribution: first, a periodic
disturbance, for which the instabilities appearing at the beginning of disturbance become regular oscillations; then a pulse
disturbance of the entry velocity field which enables us to link the additional quadratic contribution to the existence of
an accumulation of fluid at low velocity in the channel. 相似文献
936.
Processing and aging characteristics of eutectic Sn-3.5Ag solder reinforced with mechanically incorporated Ni particles 总被引:6,自引:0,他引:6
F. Guo J. Lee S. Choi J. P. Lucas T. R. Bieler K. N. Subramanian 《Journal of Electronic Materials》2001,30(9):1073-1082
Composite solders offer improved properties compared to non-composite solders. Ni reinforced composite solder was prepared
by mechanically dispersing 15 vol.% of Ni particles into eutectic Sn-3.5Ag solder paste. The average size of the Ni particle
reinforcements was approximately 5 microns. The morphology, size and distribution of the reinforcing phase were characterized
metallographically. Solid-state isothermal aging study was performed on small realistic size solder joints to study the formation
and growth of the intermetallic (IM) layers at Ni reinforcement/solder and Cu substrate/solder interfaces. Effects of reflow
on microstructure and solderability, were studied using Cu substrates. Regarding solderability, the wetting angle of multiple
reflowed Ni reinforced composite solder was compared to the solder matrix alloy, eutectic Sn-3.5Ag. General findings of this
study revealed that Ni particle reinforced composite solder has comparable wetting characteristics to eutectic Sn-3.5Ag solder.
Significant IM layers growth was observed in the Ni composite solder joint under isothermal aging at 150 C. Microstructural
evolution was insignificant when aging temperature was lower than 100 C. Multiple reflow did not significantly change the
microstructure in Ni composite solder joint. 相似文献
937.
F. Lucas S. Jaulmes M. Quarton T. Le Mercier F. Guillen C. Fouassier 《Journal of solid state chemistry》2000,150(2):404
The crystal structure of strontium dialuminodiborate SrAl2B2O7 has been established by single-crystal X-ray diffraction methods. The compound crystallizes in the trigonal system (space group R
c, Z=6) with cell parameters a=4.893(1) Å and c=47.78(1) Å. Aluminium and boron atoms are, respectively, in tetrahedral and triangular oxygen coordination. The assembly of Al2O7 units and BO3 triangles forms double layers between which Sr2+ ions are located. The Eu2+-doped crystalline powder exhibits a luminescence band with maximum at 415 nm. Luminescence characteristics are compared to those of other strontium borates. 相似文献
938.
In this paper we study the rotation transformation on binary trees and consider the properties of binary trees under this operation. The rotation is the universal primitive used to rebalance dynamic binary search trees. New binary search tree algorithms have recently been introduced by Sleator and Tarjan. It has been conjectured that these algorithms are as efficient as any algorithm that dynamically restructures the tree using rotations. We hope that by studying rotations in binary trees we shall gain a better understanding of the nature of binary search trees, which in turn will lead to a proof of this “dynamic optimality conjecture”. We define a graph, RG(n), whose vertex set consists of all binary trees containing n nodes, and which has an edge between two trees if they differ by only one rotation. We shall introduce a new characterization of the structure of RG(n) and use it to demonstrate the existence of a Hamiltonian cycle in the graph. The proof is constructive and can be used to enumerate all binary trees with n nodes in constant time per tree. 相似文献
939.
Willian Vieira de Abreu Joo Mrcio Maciel Aquilino Senra Martinez Alessandro da Cruz Gonalves Lucas Schmidt 《Entropy (Basel, Switzerland)》2022,24(10)
In the last seven years, Kaniadakis statistics, or -statistics, have been applied in reactor physics to obtain generalized nuclear data, which can encompass, for instance, situations that lie outside thermal equilibrium. In this sense, numerical and analytical solutions were developed for the Doppler broadening function using the -statistics. However, the accuracy and robustness of the developed solutions contemplating the κ distribution can only be appropriately verified if applied inside an official nuclear data processing code to calculate neutron cross-sections. Hence, the present work inserts an analytical solution for the deformed Doppler broadening cross-section inside the nuclear data processing code FRENDY, developed by the Japan Atomic Energy Agency. To do that, we applied a new computational method called the Faddeeva package, developed by MIT, to calculate error functions present in the analytical function. With this deformed solution inserted in the code, we were able to calculate, for the first time, deformed radiative capture cross-section data for four different nuclides. The usage of the Faddeeva package brought more accurate results when compared to other standard packages, reducing the percentage errors in the tail zone in relation to the numerical solution. The deformed cross-section data agreed with the expected behavior compared to the Maxwell–Boltzmann. 相似文献
940.
L'Hôte D Alard JP Augerat J Babinet R Brochard F Fodor Z Fraysse L Girard J Gorodetzky P Gosset J Laspalles C Lemaire MC Lucas B Montarou G Parizet MJ Poitou J Racca C Schimmerling W Tamain JC Terrien Y Valero J Cugnon J Vandermeulen J 《Physics letters. [Part B]》1987,198(2):139-142
Mean multiplicities of pi+ and pi- in 4He collisions with C, Cu, and Pb at 200, 600, and 800 MeV/u, and with C and Pb at 400 MeV/u have been measured using the large solid angle detector Diogene. The independence of pion multiplicity on projectile incident energy, target mass and proton multiplicity is studied in comparison with intra-nuclear cascade predictions. The discrepancy between experimental results and theory is pointed out and discussed. 相似文献