Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 6

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

Search:
in the keywords:  87.10.+e
help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1
Content available remote

X-Ray Diffraction and NMR Studies on Mixtures of Non-Ionic Surfactant (C_{12}EO_{2}) and Phospholipids (POPC)

100%
Funari S. S., di Vitta C., Rapp G.
Acta Physica Polonica A
|
1997
|
vol. 91
|
issue 5
953-960
EN
We studied the temperature and concentration dependence of the POPC/C_{12}EO_{2}/water ternary system and identified and characterized the different phases occurring. The thermal behaviour is slightly dependent on the surfactant to lipid molar ratio R_{s/l}. At low surfactant content the behaviour is similar to the binary lipid/water system. Similarly at low lipid contents the system behaves similarly to the surfactant/water mixture. However, at molar ratios R_{s/l} between 2 and 3 a new hexagonal phase forms which is peculiar to the mixture. ^{2}H NMR measurements indicated the existence of a lamellar phase containing also curved surfaces additional to the flat ones. The surface area per surfactant molecule was calculated to 0.23 nm^{2} which is in good agreement with the cross-section of a paraffinic chain.
2
Content available remote

Memory Properties of Non-Fully Interconnected Neural Network

100%
Kosiński R. A., Zagórski A.
Acta Physica Polonica A
|
1994
|
vol. 86
|
issue 3
427-433
EN
A model of a neural network consisting of two states neurons with the number N of (symmetric) synaptic connections per neuron treated as a variable was investigated numerically. Hebb's rule was used for storing uncorrelated patterns in the network. A maximal number of such patterns, which can be effectively retrieved by the network and the process of deterioration of the memory, is examined as a function of the number of synaptic connections per neuron. The influence of the number of neurons in the network as well as boundary conditions for the storage capacity of the network are discussed.
3
Publication available in full text mode
Content available

Chaotic Dynamics of a Linear Chain of Periodically Stimulated Neurons with Random Synaptic Connections

63%
Kosiński R., Krawiecki A., Sukiennicki A.
Acta Physica Polonica A
|
2001
|
vol. 100
|
issue 1
89-99
EN
Dynamics of a neural network in the form of a linear chain of artificial neurons S_i∈(-1,1) influenced by an external sinusoidal stimulation is investigated as a function of the range k of synaptic connections with random values. Time evolution of the network is periodic for small k, however, clusters of neurons oscillating with a triple period of external stimulation, with quasiperiodic or with chaotic time evolution may occur. For increasing k the number and width of the chaotic clusters increase and for k >4 the chaotic motion occurs in the whole network. A route to chaos in the considered system is discussed.
4
Content available remote

Braids for Pretzel Knots

51%
Suffczyński M.
Acta Physica Polonica A
|
2000
|
vol. 98
|
issue 6
663-671
EN
The words of braid closures for the pretzel knots, in particular the twist knots relevant to molecular supercoils in biochemistry, are recorded in a standardized form, which enables one to see the regular pattern of the words, and thus to write the braid words representing pretzel knots for general values of the crossing number.
5
Content available remote

Transient properties of a bistable kinetic model with quantum corrections

38%
Ai B.-q., Zheng H., Xie H.-z., Liu L.-g.
Open Physics
|
2006
|
vol. 4
|
issue 2
270-276
EN
The transient properties of a Brownian particle moving in a bistable system with quantum corrections are investigated. The Quantum Smoluchowski Equation (QSE) is fully valid for high temperatures; for low temperatures it is valid only in a restricted domain of the state space. The quantum effects in a bistable system stand out for low temperatures. Explicit expressions of the mean first-passage time (MFPT) are obtained by using a steepest-descent approximation. The quantum effects are against the particle moving towards the destination from its original position.
6
Content available remote

An introduction to physical theory of molecular evolution

32%
Luque B.
Open Physics
|
2003
|
vol. 1
|
issue 3
516-555
EN
This work is a tutorial in Molecular Evolution from the point of view of Physics. We discuss Eigen's model, a link between evolutionary theory and physics. We will begin by assuming the existence of (marco) molecules or replicators with the template property, that is, the capacity to self-replicate. According to this assumption, information will be randomly generated and destroyed by mutations in the code (i.e., errors in the copying process) and new bits of information will be fixed (made stable) by the existence of an external pressure on the system (i.e., selection), and the ability of the molecules to replicate themselves. Our aim is to build a model in order to describe molecular evolution from as general a standpoint as possible. As we will see, even very simple models from the theoretical point of view will have surprisingly deep consequences.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.