ISSN:0005-9021    

DOI:10.1002/bbpc.19850890602

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1985

数据来源: WILEY

ISSN:0005-9021    

DOI:10.1002/bbpc.19850890603

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1985

数据来源: WILEY

摘要:

AbstractMany systems in chemistry, physics, and biology can be described at different levels, in particular at a microscopic level and a macroscopic level. In synergetics an attempt is made to relate these two levels in order to understand and describe the formation of macroscopic structures (patterns) through selforganisation of interacting microscopic elements. The concept of order parameters allows us to describe patterns at a macroscopic level. The slaving principle relates the macroscopic to the microscopic level. ‐ We first present theoretic results on pattern formation of fluids and flames, and on morphogenesis. We then study a second class of phenomena which at the present level of our knowledge can be represented at the macroscopic level by means of suitable order parameters. We devise a mathematical model which will present the transition of a specific behavioral pattern of hand movement to another one. It is believed the such kind of modelling applies also to more complicated transitions between behavioral patterns, for instance when horses change the gaits. In the sense of synergetics a behavioral pattern is an outcome of a highly correlated function of microscopic elements. Though their behavior is not known explicitly the slaving principle shows us that such a high correlation is taking place and allows us to formulate equations in terms of order parameter

ISSN:0005-9021    

DOI:10.1002/bbpc.19850890604

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1985

数据来源: WILEY

摘要:

AbstractThe dynamics of physical or mathematical systems may follow simple rules and yet unfold in enormous complexity. Thanks to computer graphical experimentation we are beginning to detect universal scenarios some of which are reviewed here. The emphasis is on the formation of boundaries between different modes of behavior, or between basins of attraction in systems with competitive dynamics.

ISSN:0005-9021    

DOI:10.1002/bbpc.19850890605

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1985

数据来源: WILEY

摘要:

AbstractA new method for the connection of irreversible macrodynamics and reversible microdynamics is described. Starting from the phenomenological macroscopic level, in a first step a classical nonlinear Schrödinger‐type field equation for the description of dissipative systems is obtained. Properties of the logarithmic nonlinearity taking into account the irreversible behaviour of the system are discussed. In order to reach the reversible microscopic level, the nonlinearity has to be removed which can be achieved via a nonunitary transformation. Similarities with other theories aiming at connecting the two levels of description starting from reversible microdynamics are sho

ISSN:0005-9021    

DOI:10.1002/bbpc.19850890606

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1985

数据来源: WILEY

摘要:

AbstractPrigogine has emphasized that there is a “degeneracy” in quantum theory, where the Hamiltonian plays a dual role as (a) the generator of time evolution and (b) the energy observable. This prevents the exact treatment of irreversible phenomena on the microscopic quantum mechanical level. The removal of the aforementioned degeneracy can be achieved with the aid of a star‐unitary similarity transformation depending explicitly on the star‐Hermitian operator of the “intrinsic time”. Its physical significance is shown in the context of luminescence spectroscopy, where a novel kind of (dynamically induced orD‐) fluctuations around steady photoemission states is predicted. A photon counting/spectroscopic experiment has been performed which permits to detectD‐fluctuations and, at the same time, allows us to resolve broad spectroscopic bands by detection of the underlying finer “pure” vibronic transitions. The experimental findings clearly show the physical significance of Prigogine's

ISSN:0005-9021    

DOI:10.1002/bbpc.19850890607

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1985

数据来源: WILEY

摘要:

AbstractIn pool fires of liquid hydrocarbons static equidensitometric structures (2 types) and dynamic radiance structures (18 types) are obtained from flame photograms evaluated with an image analysis computer system. A third kind of structures, the dynamic synchronous structures (9 types) are visualized with a holographic real‐time interferometry method. ‐ The control parameters of the observed structures are the pool diameter, the height above the fuel surface, the density of the fuel vapor and the volumetric fuel flow rate. ‐ The dynamic radiance structures have 4 monoperiodic subprocesses with a frequency of 12 Hz (n‐hexane pool fire,d= 4.6 cm) which depend strongly on the pool diameter and show 18 statistical characteristics. The dynamic synchronous structures of the same pool fire show a quasiperiodic region I with 7 sub‐processes at 11, 13 and 3 Hz. In a quasiperiodic region II, 8 sub‐processes exist at the frequencies 11, 12, 13, 39 and 41 Hz. In addition there are 17 statistical characteristics. ‐ The effects of the observed dynamic structures on turbulent exchange processes in pool fires are calculated and lead to turbulent Prandtl‐, Schmidt‐ and Lewis‐number

ISSN:0005-9021    

DOI:10.1002/bbpc.19850890608

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1985

数据来源: WILEY

摘要:

AbstractThe global behaviour of a system (stable, conservative, explosive) can be realized applying Liapunov functions. To illustrate this, some dissipative thermodynamical examples are shown together with some autocatalytic chemical models displaying explosive behaviour.

ISSN:0005-9021    

DOI:10.1002/bbpc.19850890609

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1985

数据来源: WILEY

摘要:

AbstractExperiments and theory are reviewed on systems with multiple stable states, stabilization of unstable stationary states, oscillations, inverted Hopf bifurcations, the velocity and structure of chemical fronts and waves including the constancy of the profile in time, and structure formation in precipitation processes. Reduction of dissipation is shown possible in nonlinear systems compared to stationary state operation, by means of external periodic perturbations or oscillatory conditions, and is illustrated with thermal and biochemical engines (glycolysis).

ISSN:0005-9021    

DOI:10.1002/bbpc.19850890610

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1985

数据来源: WILEY

摘要:

AbstractIf two composition variablesXandYare sufficient to define both the thermodynamic and dynamic states of a system with acceptable accuracy, any such state can be represented by a point in a bounded region of the positive quadrant of theX‐Yplane. Any stationary state within that region must belong to one of seven behavior classes, one of which is a double degeneracy that will probably never the encountered. The other six behavior classes are illustrated by well established models. Assignment of behavior class for a specific system can be made from the dynamic parameters for local behavior by using the signs and relative magnitudes of the trace and determinant of the secular equation. An entirely equivalent assignment can be made if two of the rate constants are replaced by the directions of theXandYnullclines at the intersection which generates the stationary state. Although the secular equation is based solely on local behavior, the use of nullcline directions permits that local behavior to be impacted by global thermodynamic constraints. Such considerations show that the Lotka model with irreversible steps does not satisfy the thermodynamic constraints for a real chemical system, and only a very fortuitous combination of rate constants would permit the steady state to become the conservative center generated by the irreversible mechanism. The irreversible Brusselator model also fails to satisfy the thermodynamic constraints on a real chemical system, but the difficulty can be resolved by inclusion of reversibility. The irreversible Oregonator and Berlinator models satisfy the global constraints even with virtually no attention to reversibilit

ISSN:0005-9021    

DOI:10.1002/bbpc.19850890611

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA, Weinheim    

年代:1985

数据来源: WILEY