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991.
Manoel Manghi Nicolas Destainville John Palmeri 《The European physical journal. E, Soft matter》2012,35(10):1-13
We investigate the dynamical behavior of simple networks, namely loops with an additional internal regulating connection. Continuous dynamics for mRNA and protein concentrations is compared to a Boolean model for gene activity. Using a generalized method and within a single framework, we study different continuous models and different types of regulatory functions, and establish conditions under which the system can display stable oscillations or stable fixed points. These conditions depend only on general features such as the degree of cooperativity of the regulating interactions and the logical structure of the interactions. There are no simple rules for deciding when Boolean and continuous dynamics agree with each other, but we identify several relevant criteria. 相似文献
992.
A simple concept is proposed for templating in situ synthesised CdSe quantum dots (QDs) into an organised nano-pattern using
the crystalline lamellae structure of polyamide 66 (PA66). The morphology obtained for PA66 and the hybrid material on Si/SiO
x
solid substrate was characterised by means of atomic force microscope. Controlling the PA66 concentration in solution and
the organic–inorganic interactions are found to be the keys factors to direct the assembly of CdSe QDs along the PA66 linear
crystalline structure. This simple approach could be opened a new avenue for a large spectrum of innovative high-tech applications. 相似文献
993.
Gavin Cullen Nicolas Greiner Gudrun Heinrich Gionata Luisoni Pierpaolo Mastrolia Giovanni Ossola Thomas Reiter Francesco Tramontano 《The European Physical Journal C - Particles and Fields》2012,72(3):1-32
We present the program package GoSam which is designed for the automated calculation of one-loop amplitudes for multi-particle processes in renormalisable quantum field theories. The amplitudes, which are generated in terms of Feynman diagrams, can be reduced using either D-dimensional integrand-level decomposition or tensor reduction. GoSam can be used to calculate one-loop QCD and/or electroweak corrections to Standard Model processes and offers the flexibility to link model files for theories Beyond the Standard Model. A standard interface to programs calculating real radiation is also implemented. We demonstrate the flexibility of the program by presenting examples of processes with up to six external legs attached to the?loop. 相似文献
994.
Synchronized oscillations are of critical functional importance in many biological systems. We show that such oscillations can arise without centralized coordination in a disordered system of electrically coupled excitable and passive cells. Increasing the coupling strength results in waves that lead to coherent periodic activity, exhibiting cluster, local and global synchronization under different conditions. Our results may explain the self-organized transition in a pregnant uterus from transient, localized activity initially to system-wide coherent excitations just before delivery. 相似文献
995.
Entanglement and nonlocality are both fundamental aspects of quantum theory, and play a prominent role in quantum information science. The exact relation between entanglement and nonlocality is, however, still poorly understood. Here we make progress in this direction by showing that, contrary to what previous work suggested, quantum nonlocality does not imply entanglement distillability. Specifically, we present analytically a 3-qubit entangled state that is separable along any bipartition. This implies that no bipartite entanglement can be distilled from this state, which is thus fully bound entangled. Then we show that this state nevertheless violates a Bell inequality. Our result also disproves the multipartite version of a long-standing conjecture made by Peres. 相似文献
996.
M Piponnier R Horisaki G Druart N Guérineau A Kattnig J Primot 《Optics letters》2012,37(17):3492-3494
We have designed miniaturized, simple, and robust cameras composed of a single diffractive optical element (DOE) that generates a continuously self-imaging (CSI) beam. Two different DOEs are explored: the J0 Bessel transmittance, characterized by a continuous optical transfer function (OTF) and the CSI grating (CSIG), characterized by a sparse OTF. In this Letter, we will analyze the properties of both DOEs in terms of radiometric performances. We will demonstrate that the noise robustness is enhanced for a CSIG, thanks to the sparsity of its OTF. A camera using this DOE has been made and experimental images are presented to illustrate the noise robustness. 相似文献
997.
Under strong laser illumination, few-layer graphene exhibits both a transmittance increase due to saturable absorption and a nonlinear phase shift. Here, we unambiguously distinguish these two nonlinear optical effects and identify both real and imaginary parts of the complex nonlinear refractive index of graphene. We show that graphene possesses a giant nonlinear refractive index n(2)?10(-7) cm(2) W(-1), almost 9 orders of magnitude larger than bulk dielectrics. We find that the nonlinear refractive index decreases with increasing excitation flux but slower than the absorption. This suggests that graphene may be a very promising nonlinear medium, paving the way for graphene-based nonlinear photonics. 相似文献
998.
Martin Vérot Dr. Nicolas Bréfuel Dr. Jacques Pécaut Prof. Cyrille Train Prof. Vincent Robert 《化学:亚洲杂志》2012,7(2):380-386
The oxidation of 1,5‐dimethyl‐3‐(2′‐pyridyl)‐6‐thiooxotetrazane (SvdH3py) by benzoquinone leads to a 1:1 adduct of 1,5‐dimethyl‐3‐(2′‐pyridyl)‐6‐thiooxoverdazyl radical (Svdpy) with hydroquinone (hq). The single‐crystal X‐ray diffraction of this adduct at room temperature (RT) shows that the radicals exhibit a slight curvature that leads to the formation of alternating head‐to‐tail (antiparallel) stacked 1D chains. Moreover, temperature‐dependent X‐ray measurements at 100, 200, and 303 K reveal that the lateral slippages between the radicals of the stacks |δ1| and |δ2| vary from 0.64 to 0.78 Å and 0.54 to 0.40 Å between 100 and 303 K. Despite the alternation of the inter‐radical distances and lateral slippages, the magnetic susceptibility data can be fitted with excellent agreement using a regular one‐dimensional antiferromagnetic chain model with J=?5.9 cm?1. Wavefunction‐based calculations indicate an alternation of the magnetic interaction parameters correlated with the structural analysis at RT. Moreover, they demonstrate that the thermal slippage of the radicals induces a switching of the physical behavior, since the exchange interaction changes from antiferromagnetic (?0.9 cm?1) at 100 K to ferromagnetic (1.4 cm?1) at 303 K. The theoretical approach thus reveals a much richer magnetic behavior than the analysis of the magnetic susceptibility data and ultimately questions the relevance of a spin‐coupled picture based on temperature‐independent parameters. 相似文献
999.
H. P. Winkler D. Topa E. Keller 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(7):i45-i49
The title phase (pentalead triindium pentabismuth heptadecasulfide) has been synthesized and structurally characterized. Its structure contains mixed Bi/In, In/Bi and Pb/In positions; all atoms lie on crystallographic mirror planes. The structural relationship between Pb5In3Bi5S17 and a phase known by the formula Pb4In3Bi7S18 is discussed. A comparatively large and complex structural `seed' is defined which is common to both phases. The structural changes within this seed when moving from one phase to the other are described by graphical means. 相似文献
1000.
Mondal S Nechab M Vanthuyne N Bertrand MP 《Chemical communications (Cambridge, England)》2012,48(19):2549-2551
The tandem Crabbé homologation-radical rearrangement of terminal enediynes leads, in a one-pot procedure, to the enantioselective synthesis of six- and seven-membered ring α-aminoesters bearing a quaternary stereocenter based on the phenomenon of memory of chirality. 相似文献