190 resultados para Operation range


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In this paper, we studied range-based attacks on links in geographically constrained scale-free networks and found that there is a continuous switching of roles of short-and long-range attacks on links when tuning the geographical constraint strength. Our results demonstrate that the geography has a significant impact on the network efficiency and security; thus one can adjust the geographical structure to optimize the robustness and the efficiency of the networks. We introduce a measurement of the impact of links on the efficiency of the network, and an effective attacking strategy is suggested

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We report the first three-particle coincidence measurement in pseudorapidity (Delta eta) between a high transverse momentum (p(perpendicular to)) trigger particle and two lower p(perpendicular to) associated particles within azimuth |Delta phi| < 0.7 in root s(NN) = 200 GeV d + Au and Au + Au collisions. Charge ordering properties are exploited to separate the jetlike component and the ridge (long range Delta eta correlation). The results indicate that the correlation of ridge particles are uniform not only with respect to the trigger particle but also between themselves event by event in our measured Delta eta. In addition, the production of the ridge appears to be uncorrelated to the presence of the narrow jetlike component.

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The tertiary lanthanide complexes [Ln(hfth)(3)phen] (Ln=Er, Nd, Yb, Sm) and [Pr(tfnb)(3)phen] have been Successfully covalently attached in the ordered SBA-15 mesoporous materials via a functionalized 1,10-phenanthroline group 5-(N,N-bis-3-(triethoxysilyl)propyl)ureyl-1,10-phenanthroline (Phen-Si). The derivative materials [denoted as Ln(hfth)(3)phen-S15 and Pr(tfnb)(3)phen-S15; Ln=Er, Yb, Nd, Sm; hfth=4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)hexane-1,3-dionate; tfnb=4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedionate] were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and N-2 adsorption/desorption.

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A series of novel pH- and temperature-responsive diblock copolymers composed of poly(N-isopropylacrylamide) (PNIPAM) and poly[(L-glutamic acid)-co-(gamma-benzyl L-glutamate)] [P(GA-co-BLG)] were prepared. The influence of hydrophobic benzyl groups on the phase transition of the copolymers was studied for the first time. With increasing BLG content in P(GA-co-BLG) block, the thermal phase transition of the diblock copolymer became sharper at a designated pH and the critical curve of phase diagram of the diblock copolymer shifted to a higher pH region.

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Here, we report a simple and Sensitive colorimetric detection method for Hg2+ ions With a tunable detection range based on DNA oligonucleotides and unmodified gold nanoparticles (DNA/AuNPs) sensing system. Complementary DNA strands with T-T mismatches could effectively protect AuNPs from salt-induced aggregation. While in the presence of Hg2+ ions T-Hg2+-T coordination chemistry leads to the formation of DNA duplexes, and AuNPs are less well protected thus aggregate at the same salt concentration, accompanying by color change from red to blue. By rationally varying the number of T-T mismatches in DNA oligonucleotides, the detection range could be tuned.

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CeF3 and CeF3:Tb3+ nanoparticles were prepared by reverse microemulsion with a functional monomer, methyl methacrylate (MMA), as the oil phase, and CeF3:Tb3+/poly (methyl methacrylate) (PMMA) nanocomposites were obtained via polymerization of the MMA monomer. The nanoparticles and nanocomposites have been well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), low- and high-resolution transmission electron microscope (TEM), selected-area electron diffraction (SAED), thermogravimetric analysis (TGA), UV/vis transmission spectra, photoluminescence excitation, and emission spectra and luminescence decays. The well-crystallized CeF3 and CeF3:Tb3+ nanoparticles are spherical with a mean diameter of 15 nm. They show the characteristic emission of Ce3+ 5d-4f (313 nm, D-2-F-2(5/2); 323 nm, D-2-F-2(7/2)) and Tb3+ D-5(4)-F-7(J) (J = 6-3, with D-5(4)-F-7(5) green emission at 541 nm as the strongest one) transitions, respectively.

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Pentacene thin-film transistors have been obtained using polymethyl-methacrylate-co-glyciclyl-methacrylate (PNIMA-GMA) as the gate dielectric. The optimum active layer thickness in thin-film transistors (OTFTs) was investigated. The present devices show a wide operation voltage range. The on/off current ratio is as high as 10(5). In linear region (V-DS = -2V), the field-effect mobility of device increases with the increase in gate field at low-voltage region (V-G < - 20 V), and a mobility of 0.33 cm(2)/Vs can be obtained when V-G > 20 V. In saturation region, the mobility increases linearly with the gate field, and a high mobility of 1.14 cm(2)/Vs can be obtained at V-G = -95V. The influence of voltage on mobility of device was investigated.

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A series of acrylonitrile-butadiene-styrene (ABS) with different rubber content were prepared by diluting ABS grafting copolymer containing 60% rubber with a styrene-acrylonitrile copolymer. ABS prepared were blended with bisphenol-A-polycarbonate (PC) at the ratio of 70/30, 50/50, and 30/70 to prepare PC/ABS blends. Influence of rubber content in ABS on the properties of ABS and PC/ABS blends were investigated. PC/ABS blends with different compositions got good toughness when the rubber in ABS increased to the level that ABS itself got good toughness. The tensile properties and processability of PC/ABS blends decreased with the increase of the total rubber content introduced into the blends. ABS with the rubber content of 30 wt% is most suitable to be used to prepare PC/ABS blends. The rubber content in ABS affected the viscosity of ABS, and subsequently the viscosity ratio of PC to ABS. As a result, the morphology of PC/ABS blends varied. The increase of rubber content in ABS results in finer structure of PC/ABS blends.

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The optical properties of rare earth ions-activated barium orthophosphate phosphors, Ba-3(PO4)(2):RE (RE = Ce3+, Sm3+, Eu3+, Eu2+, and Tb3+), were investigated in vacuum ultraviolet (VLTV)-Vis range. A band-band transition Of PO43- in Ba-3(PO4)(2) is observed in the region of 150-170 nm. The partial reduction of Eu3+ to Eu2+ was observed and confirmed by luminescent spectra under the VUV-UV excitation. It is proposed that the electronegative defects that formed by aliovalent substitution of Eu3+ on the Ba2+ site in the host are responsible for the reduction process.

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Two new concepts for molecular solids, 'local similarity' and 'boundary-preserving isometry', are defined mathematically and a theorem which relates these concepts is formulated. 'Locally similar' solids possess an identical short-range structure and a 'boundary-preserving isometry' is a new mathematical operation on a finite region of a solid that transforms mathematically a given solid to a locally similar one. It is shown further that the existence of such a 'boundary-preserving isometry' in a given solid has infinitely many 'locally similar' solids as a consequence. Chemical implications, referring to the similarity of X-ray powder patterns and patent registration, are discussed as well. These theoretical concepts, which are first introduced in a schematic manner, are proved to exist in nature by the elucidation of the crystal structure of some diketopyrrolopyrrole (DPP) derivatives with surprisingly similar powder patterns. Although the available powder patterns were not indexable, the underlying crystals could be elucidated by using the new technique of ab initio prediction of possible polymorphs and a subsequent Rietveld refinement. Further ab initio packing calculations on other molecules reveal that 'local crystal similarity' is not restricted to DPP derivatives and should also be exhibited by other molecules such as quinacridones. The 'boundary-preserving isometry' is presented as a predictive tool for crystal engineering purposes and attempts to detect it in crystals of the Cambridge Structural Database (CSD) are reported.