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51.
To minimize traffic congestion, understanding how traffic dynamics depend on network structure is necessary. Many real-world complex systems can be described as multilayer structures. In this paper, we introduce the idea of layers to establish a traffic model of two-layer complex networks. By comparing different two-layer complex networks based on random and scale-free networks, we find that the physical layer is much more important to the network capacity of two-layer complex networks than the logical layer. Two-layer complex networks with a homogeneous physical topology are found to be more tolerant to congestion. Moreover, simulation results show that the heterogeneity of logical and physical topologies makes the packet-delivery process of two-layer networks more efficient in the free-flow state, without the occurrence of traffic congestion. 相似文献
52.
Given two bounded linear operators $P$ and $Q$ on a Banach space the formula for the Drazin inverse of $P+Q$ is given, under the assumptions $P^2 Q+PQ^2=0$ and $P^3 Q=PQ^3=0$ . In particular, some recent results arising in Drazin (Am Math Mon 65:506–514, 1958), Hartwig et al. (Linear Algebra Appl 322:207–217, 2001) and Castro-González et al. (J Math Anal Appl 350:207–215, 2009) are extended. 相似文献
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54.
To optimize the performance of longitudinally pumped Yb3+:Y2O3 ceramic lasers, cavity parameters such as material length and output coupler transmission at a certain laser output power are calculated numerically using quasi-three-level laser model. The results show great potential of Yb3+:Y2O3 ceramics for highly efficient diode-pumped solid-state lasers. 相似文献
55.
The transformation of SiO2 from low pressure tetrahedral phases into denser octahedral phases takes place via the collapse of the oxygen sublattice into a close-packed arrangement. The transition paths and the resulting products are known to be affected by the presence of anisotropic stresses, which are difficult to control, so interpretation of the experimental results is problematic. Based on nonhydrostatic molecular dynamics simulations, we show that the collapse of the oxygen sublattice in the specific case of cristobalite is concomitant with the disappearance of tetrahedral units and that non hydrostatic stresses can be tuned to yield phases with different oxygen close-packed sublattices, including the alpha-PbO2-like phase, for which we provide a microscopic formation path, and phases with a cubic close packing, like anatase, not seen in experiments yet. 相似文献
56.
Nan Zhang Tao Bing Xiangjun Liu Cui Qi Luyao Shen Linlin Wang Dihua Shangguan 《Chemical science》2015,6(7):3831-3838
Guanine-rich oligonucleotides (GROs) have attracted considerable attention as anticancer agents, because they exhibit cancer-selective antiproliferative activity and can form G-quadruplex structures with higher nuclease resistance and cellular uptake. Recently, a GRO, AS1411 has reached phase II clinical trials for acute myeloid leukemia and renal cell carcinoma. The antiproliferative activity of GROs has been associated with various protein targets; however the real mechanisms of action remain unclear. In this study, we showed evidence that antiproliferative activity of GROs (including AS1411) is mainly contributed by the cytotoxicity of their guanine-based degradation products, such as monophosphate deoxyguanosine (dGMP), deoxyguanosine (dG) and guanine. The GROs with lower nuclease resistance exhibited higher antiproliferative activity. Among nucleotides, nucleosides and nucleobases, only guanine-based compounds showed highly concentration-dependent cytotoxicity. Our results suggest that it is necessary to reconsider the cancer-selective antiproliferative activity of GROs. Since guanine-based compounds are endogenous substances in living organisms, systematic studies of the cytotoxicity of these compounds will provide new information for the understanding of certain diseases and offer useful information for drug design. 相似文献
57.
The Influencing Mechanism of Acidity on the Oxidation Peak Currents of Uric Acid and Ascorbic Acid at the PACPE by Cyclic Voltammetry
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In this paper, a pre‐anodized carbon paste electrode (PACPE) is fabricated by a simple electrochemical pretreatment method, which can be used for the simultaneous determination of uric acid (UA) and ascorbic acid (AA). The influencing mechanism of the acidity on the size of oxidation peak current (ip,a) of UA and AA is discussed in detail. According to the results, in different pH conditions, the intensity of hydrogen bonding between UA, AA and the surface of PACPE, the degree of reduction reaction at the auxiliary electrode, and the structural configurations of UA and AA with different species in reaction system have evident influence on the size of oxidation peak current. In pH 7.00 phosphate buffer solution, the calibration curves for UA and AA are obtained in the range of 5.0 x 10‐7–5.0 x 10‐5 mol/L and 3.0 x 10‐5–5.0 x 10‐3 mol/L, respectively. The detection limits for UA and AA are found to be 2.0 x 10‐8 mol/L and 1.2 x 10‐6 mol/L, respectively. This proposed method has been successfully applied to determine UA and AA in human urine simultaneously with satisfactory results. 相似文献
58.
Sandwich‐Structured Graphene–Nickel Silicate–Nickel Ternary Composites as Superior Anode Materials for Lithium‐Ion Batteries
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Renxi Jin Yang Yang Yunfeng Li Xianchun Liu Prof. Yan Xing Dr. Shuyan Song Prof. Zhan Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(25):9014-9017
We report the synthesis of sandwich‐structured graphene–nickel silicate–Ni ternary composites by using the solvothermal method followed by a simple in situ reduction procedure. The composites show an interesting structure with graphene sandwiched between two layers of well‐dispersed Ni nanoparticles (NPs) anchored on ultrathin nickel silicate nanosheets. These ternary composites exhibit enhanced performance as anode materials owing to the synergistic effect between the graphene matrix and electrochemically inert Ni nanoparticles, an effect that holds promise for the design and fabrication of other advanced electrode materials. 相似文献
59.
Yunfeng Xu Chong Zhang Pan Mu Na Mao Xue Wang Qian He Feng Wang Jia-Xing Jiang 《中国科学:化学(英文版)》2017,60(8):1075-1083
Two novel tetra-armed conjugated microporous polymers with different geometries have been designed and synthesized via Suzuki-Miyaura cross coupling polycondensation. Both polymers are stable in various organic solvents tested and are thermally stable. The pyrene-containing polymer of PrPy with the rigid pyrene unit shows a higher Brunauer-Emmet-Teller specific surface area of 1219 m2 g?1 than the tetraphenylethylene-containing polymer of PrTPE (770 m2 g?1), which leads to a high CO2 uptake ability of 3.89 mmol g?1 at 1.13 bar/273 K and a H2 uptake ability of 1.69 wt% at 1.13 bar/77 K. The photocatalytic hydrogen production experiments revealed that PrPy also shows a better photocatalytic performance than PrTPE due to the higher conjugation degree and planar structure, the broader UV-visible (UV-Vis) absorption, the lower photoluminescence lifetime, and the higher specific surface area. 相似文献
60.