Pattern dynamics in cellular perception

By using a giant amoeboid cell of the Physarum plasmodium, changes in the intracellular distribution of chemical components are studied in relation to information processing in cell behavior. Various kinds of metabolites oscillate, and so the protoplasm should be a collection of chemical oscillators. Spatially, characteristic chemical patterns are self-organized for different cell shapes, and hence cell behavior. New phase waves propagate throughout the cell upon local stimulation, their direction being opposite for attraction and repulsion. Locomotion is inhibited when the coherence of the oscillators breaks. Thus, pattern dynamics is correlated with information processing in the amoeboid cell.     

Scaling spectra and return times of dynamical systems

The grand canonical version of the spectrum of singularities formalism is presented, relying naturally upon certain Markov transition graphs. The structure of a graph is simply determined by the close return times of the dynamical system described. Thus, an intimate connection exists between the shape of the singularity curve and a small but interesting set of dynamical properties.     

三核铁甲酸簇合物[Fe_3(μ_3-O)(μ-O_2CH)_6(H_2O)_2(O_2CH)]·2H_2O在乙炔、水汽体系中的反应行为

本文研究了[Fe_3(μ_3-O)(μ-O_2CH)_6(H_2O)_2(O_2CH)]·2H_2O(简称)在乙炔、水汽体系中的反应行为。发现当温度高于220℃,脱落部分配体的具有活化乙炔进行加成反应的性能。采用原位红外光谱法和气相色谱法对此反应过程进行了跟踪探索,报道了产物的定性及半定量结果。     

Essential Work of Fracture Parameters of Injection-Molded Polypropylene/Polyolefin Elastomer Blends

The influence of polyolefin elastomer (POE) content on the fracture behavior of injection-molded polypropylene (PP)/POE blends was evaluated by means of the essential work of fracture (EWF) method. The results indicated that the EWF approach worked well for the PP/POE blends when POE content was 0～7.5 wt% of the blends. The specific essential work of fracture (w _e) increased with increasing POE content, and the dominant factor that affected w _e was the necking and subsequent fracture process. The specific nonessential work of fracture (βw _p) slightly decreased with increasing POE content, while the specific plastic work (w _p) showed an increasing trend with the decrease of the shape factor (β) of the specimen. Finally, it was shown that w _e could be predicted reasonably well via the COD values.     

Radiation Processed Styrene-Butadiene Rubber/Ethylene-Propylene Diene Rubber/Multiple-Walled Carbon Nanotubes Nanocomposites: Effect of MWNT Addition on Solvent Permeability Behavior

Different compositions of SBR/EPDM 50:50 blends containing multiple-walled carbon nanotubes (MWNT) as nanoparticulate fillers (0.5%–10%) were evaluated for radiation sensitivity and solvent permeability. The efficiency of radiation ***cross-linking was analyzed by gel-content and Charlesby–Pinner parameter measurements. ***Gamma-radiation-induced cross-linking extent was found to increase with radiation dose and MWNT concentration, which was reflected in different extents of swelling. Rigorous analysis of swelling and diffusion data, on the basis of the transport exponent (n) values and diffusion/relaxation rate indicated anomalous diffusion behavior for most of the nanocomposites. The swelling extent in different solvents was found to be a function of polymer-solvent interaction as well as stearic hindrance due to the structure/size of the solvent molecules. Polymer-filler interaction investigated by a Kraus plot indicated high reinforcement of the SBR/EPDM matrix on MWNT addition. There was no significant change in surface energy or hydrophilicity of the SBR/EPDM matrix on introduction of MWNT into it.     

The phase diagram of the Flory-Huggins-de Gennes model of a binary polymer blend

We undertake a numerical study of the Flory-Huggins-de Gennes functional ind=3 dimensions describing a polymer blend. By discretising the functional on a three-dimensional lattice and employing the hybrid Monte Carlo simulation algorithm, we investigate to what extent the inclusion of the term describing fluctuations in local polymer concentration alters the phase diagram of the model. We find that, despite the relatively small weight of the fluctuation term, the coexistence curve is shifted by an appreciable amount from that predicted by naive mean-field theory, which ignores such spatial fluctuations. The direction of the shift is consistent with that already observed in experiment and in simulations of microscopic models of polymer blends. A finite-size scaling analysis indicates that the critical behavior of the model seems to belong to the 3D Ising universality class rather than being mean-field in nature.It is a pleasure to dedicate this paper to Oliver Penrose on the occasion of his 65th birthday.     

Different self-avoiding walks on percolation clusters: A small-cell real-space renormalization-group study

We calculate the average number of stepsN for edge-to-edge, normal, and indefinitely growing self-avoiding walks (SAWs) on two-dimensional critical percolation clusters, using the real-space renormalization-group approach, with small H cells. Our results are of the formN=AL ^D _SAW+B, whereL is the end-to-end distance. Similarly to several deterministic fractals, the fractal dimensionsD _SAW for these three different kinds of SAWs are found to be equal, and the differences between them appear in the amplitudesA and in the correction termsB. This behavior is atributed to the hierarchical nature of the critical percolation cluster.     

Solution of approximate gluon evolution equation for small-x at fixed ‘ρ’

A simple method has been applied to solve the approximate gluon evolution equation for small-x at fixedρ(≡√ln(x ₀/x)/ln[ln(Q ²/Λ²)/ln(Q ₀ ² /Λ²)]. Numerical comparison is made with the predictions from ‘double asymptotic scaling’ and fit. Better agreement is found between our solution and fit nearρ=1. The solution gives approximate double scaling in this region having ‘hard’ pomeron with small contamination.