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951.
We demonstrate that the self-similarity of some scale-free networks with respect to a simple degree-thresholding renormalization scheme finds a natural interpretation in the assumption that network nodes exist in hidden metric spaces. Clustering, i.e., cycles of length three, plays a crucial role in this framework as a topological reflection of the triangle inequality in the hidden geometry. We prove that a class of hidden variable models with underlying metric spaces are able to accurately reproduce the self-similarity properties that we measured in the real networks. Our findings indicate that hidden geometries underlying these real networks are a plausible explanation for their observed topologies and, in particular, for their self-similarity with respect to the degree-based renormalization. 相似文献
952.
We study a lattice model of attractive colloids. It is exactly solvable on sparse random graphs. As the pressure and temperature are varied, it reproduces many characteristic phenomena of liquids, glasses, and colloidal systems such as ideal gel formation, liquid-glass phase coexistence, jamming, or the re-entrance of the glass transition. 相似文献
953.
Nilius N Ganduglia-Pirovano MV Brázdová V Kulawik M Sauer J Freund HJ 《Physical review letters》2008,100(9):096802
Low-temperature STM measurements combined with density functional theory calculations are employed to study the adsorption of gold on alumina/NiAl(110). The binding of Au monomers involves breaking of an oxide Al-O bond below the adatom and stabilizing the hence undercoordinated O ion by forming a new bond to an Al atom in the NiAl. The adsorption implies negative charging of the adatom. The linear arrangement of favorable binding sites induces the self-organization of Au atoms into chains. For every ad-chain, the number of transfer electrons from the support is determined by analyzing the node structure of the corresponding highest occupied molecular orbital. 相似文献
954.
Mocek T Rus B Kozlová M Polan J Homer P Juha L Hájková V Chalupský J 《Optics letters》2008,33(10):1087-1089
We report on a single-shot micropatterning of an organic polymer achieved by ablation with demagnifying projection using a Ne-like Zn 21.2 nm soft x-ray laser. A nickel mesh with a period of 100 microm was approximately 10x demagnified and imprinted on poly(methyl methacrylate) via direct ablation. The quality of the ablated microstructure was found to be mainly dependent on the quality of the projected mask. This first demonstration (to our knowledge) of single-shot projection, single-step lithography illustrates the potential of soft x-ray lasers for the direct patterning of materials with a resolution scalable down to submicrometer domain. 相似文献
955.
We study the superfluid-to-Mott insulator transition of bosons in a two-legged ladder optical lattice of a type accessible in current experiments on double-well optical lattices. The zero-temperature phase diagram is mapped out, with a focus on its dependence upon interchain hopping and the tilt between double wells. We find that the unit-filling Mott phase exhibits a nonmonotonic behavior as a function of the tilt parameter, producing a reentrant phase transition between the Mott insulator and superfluid phases. 相似文献
956.
957.
958.
Henrique N. Sá Earp Vladmir Sicca Bernardo B. C. Kyotoku 《Brazilian Journal of Physics》2016,46(6):683-688
We describe the mathematical scheme for an anomaly-free ideal spectrometer, based on a 2?dimensional plane medium with conical regions of bounded slope. Moreover, the construction may be realised in many different configurations. 相似文献
959.
Cristiano Egevardt Siddhartha O. K. Giese Alan D. da C. Santos Andersson Barison Eduardo L. de Sá Arion Zandoná Filho Thiago A. da Silva Sônia F. Zawadzki Jaísa F. Soares Giovana G. Nunes 《Journal of polymer science. Part A, Polymer chemistry》2014,52(17):2509-2517
The ionic [Ti3(µ3‐OPri)2(µ‐OPri)3(OPri)6][FeCl4] halo‐alkoxide ( A ) was investigated for its activity towards the bulk polymerization of rac‐lactide (rac‐LA) and ?‐caprolactone (?‐CL) in various temperatures, monomer/ A molar proportions, and reaction times. The reactivity of A in the ring‐opening polymerization (ROP) of both monomers is mainly due to the cationic [Ti3(OPri)11]+ unity and proceeds through the coordination–insertion mechanism. Molecular weights ranging from 6,379 to 13,950 g mol?1 and PDI values varying from 1.22 to 1.52 were obtained. Results of ROP kinetic studies for both ?‐CL and rac‐LA confirm that the reaction rates are first‐order with respect to monomers. The production of poly(?‐caprolactone) shows a higher sensitivity of the reaction rate to temperature, while the polymerization of rac‐LA is slower and more dependent on the thermal stability of the active species during the propagation step. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2509–2517 相似文献
960.
There has been growing interest in the quantitative determination of biochemical predictors of atherogenesis. The aim of the present study was to investigate association of lipoperoxidation biomarkers known to be pro-atherogenic (thiobarbituric acid reactive substance activity, TBARS) or anti-atherogenic (alpha-tocopherol) with the fatty acid status, and relate it to the coronary artery disease (CAD) as assessed by coronary angiography in patients with stable angina pectoris. We found that serum lipoproteins and TBARS did not differ significantly. However there was significant correlation of TBARS with total vitamin E (P=0.02) and vitamin E in very low-density lipoprotein (VLDL) (P=0.02) and low-density lipoprotein (LDL) (P=0.01), with LDL-linoleic acid (P=0.01), and high-density lipoprotein-linoleic acid (P=0.02). There was significant correlation of total vitamin E (P=0.01) and VLDL-vitamin E (P=0.01) with the degree of CAD. We conclude that TBARS and alpha-tocopherol could not be evaluated as biomarkers for the severity of CAD among the patients with stable angina pectoris. 相似文献