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Topic: Phase transition

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In the News (Fri 23 Feb 18)

 Phase (matter) - Wikipedia, the free encyclopedia
The transition from a liquid phase to a solid phase is called freezing (or "melting" if we go in the opposite direction), and it is a type of phenomenon known as a phase transition.
In contrast, in the plasma phase the atoms are dissociated, i.e.
Phases are emergent phenomena produced by the self-organization of a macroscopic number of particles.
en.wikipedia.org /wiki/Phase_(matter)   (2719 words)

 Phase transition - Wikipedia, the free encyclopedia
In physics, a phase transition, (or phase change) is the transformation of a thermodynamic system from one phase to another.
Phase transitions happen when the free energy of a system is non-analytic for some choice of thermodynamic variables - see phases.
The various solid/liquid/gas transitions are classified as first-order transitions because they involve a discontinuous change in density (which is the first derivative of the free energy with respect to chemical potential.) Second-order phase transitions have a discontinuity in a second derivative of the free energy.
en.wikipedia.org /wiki/Phase_transition   (2103 words)

 Phase transition   (Site not responding. Last check: 2007-10-20)
A phase transition is the transformation of a thermodynamic system from one phase to another.
The ferromagnetic transition is another example of a symmetry-breaking transition, in this case time-reversal symmetry.
For 0 < α < 1, the heat capacity diverges at the transition temperature (though, since α < 1, the divergence isn't strong enough to produce a latent heat.) An example of such behavior is the 3-dimensional ferromagnetic phase transition.
www.wordlookup.net /ph/phase-transition.html   (1717 words)

 Phase Changes
Transitions between solid, liquid, and gaseous phases typically involve large amounts of energy compared to the specific heat.
The data for the vaporization phase change presumes that the pressure is one standard atmosphere.
In discussing the energy of the phase changes in water, we found that the potential energy is treated as a negative quantity.
hyperphysics.phy-astr.gsu.edu /hbase/thermo/phase.html#c1   (747 words)

 Calvin and phase transition
We think that by using a description of Calvin's model that includes phase transitions we can add details that Calvin's description lacks, specifically in relationship to what could be the synaptic event of syntax and more abstracted forms of vocables such as functional vocabulary.
He does mention that a resolution of competition is the result of a phase transition.
Phase transitions could explain much in the activation of structure in low-connectivity or ``hurry up'' time.
www.cecm.sfu.ca /~thalie/PhD/node83.html   (404 words)

 Welcome to Phase Bioscience, Inc.
Phase Bioscience develops and distributes the deltaPhase™ Technology, based on an elastin-like polypeptide (ELP) which undergoes a reversible, inverse phase transition in response to changes in the solution.
The fusion is easily isolated by inducing the phase transition, isolating the aggregated fusion from the cell lysate.
The deltaPhase Technology has been extended to enzyme biocatalysis, using the ELP as a soluble carrier for enzymes where the phase transition is used to recover the enzyme from solution.
www.phasebio.com   (129 words)

 Phase Transition
A common example is the gas-liquid phase transition undergone by water.
In such a transition, a plot of density versus temperature shows a distinct discontinuity at the critical temperature marking the transition point.
In nonlinear dynamical systems, the transition from self-organizing to chaotic behavior is sometimes referred to as a phase transition (or, more specifically, as an order-disorder transition).
www.iscid.org /encyclopedia/Phase_Transition   (99 words)

 Determination of Lalpha -HII Phase Transition Temperature for 1,2-Dioleoyl-sn-Glycero-3-Phosphatidylethanolamine -- ...
Gel to liquid crystalline phase transitions are responsible for leakage from dry pollen during rehydration.
Energetics of a hexagonal-lamellar-hexagonal-phase transition sequence in dioleoylphosphatidylethanolamine membranes.
Phases and phase transitions of the hydrated phosphatidylethanolamines.
www.biophysj.org /cgi/content/full/82/5/2504   (2671 words)

 Phase Transition and Language
It is possible that the fine grained description of phase transitions in the dynamics of synaptic functions may have some influence in the generation of linguistic structures within individuals.
First-order phase transition is of particular interest because the consequence of the process is irreversible.
The transition of lexical to functional vocabulary can be viewed as irreversible as well, which supports the notion that the structural change in vocables may occur through a first order phase transition.
www.cecm.sfu.ca /~thalie/PhD/node57.html   (374 words)

 Phase Transitions
Phase transitions can have a wide variety of important implications including the formation of topological defects -cosmic strings, domain walls, monopoles and textures - that will be discribed in more detail in the following pages, or it may even trigger a period of exponential expansion (inflation).
First-order phase transitions (illustrated below) occur through the formation of bubbles of the new phase in the middle of the old phase; these bubbles then expand and collide until the old phase disappears completely and the phase transition is complete.
During a first-order phase transition, the matter fields get trapped in a `false vacuum' state from which they can only escape by nucleating bubbles of the new phase, that is, the `true vacuum' state.
www.damtp.cam.ac.uk /user/gr/public/cs_phase.html   (1007 words)

 Molecular Dynamics Simulation of Spontaneous Membrane Fusion during a Cubic-Hexagonal Phase Transition -- Marrink and ...
the transition and of the structures of the intermediate phases.
We observed a phase transition from the diamond cubic phase to the inverted hexagonal phase of monoolein in a 60-ns MD simulation,
Siegel, D. The modified stalk mechanism of lamellar/inverted phase transitions and its implications for membrane fusion.
www.biophysj.org /cgi/content/full/83/5/2386   (3329 words)

 PAC.phase transition   (Site not responding. Last check: 2007-10-20)
The tetragonal phase is important both because it yields information about the normal state and therefore clues about the mechanism of superconductivity and because the knowledge of the transition to superconductivity is useful to optimize the superconducting state itself.
However, the study of oxygen motion and kinetics in the tetragonal phase in films is equally important, since it cannot always be assumed that the results from the investigations of the bulk are valid in films.
In powdered material, the phase transition from O to T is evident between 600-625°C depending on the surrounding atmosphere.
www.physics.orst.edu /~platzer/JMR_htc_film_97.html   (3890 words)

 CRYSTAL Tutorial Project - Phase transitions tutorial
This tutorial is devoted to the study of pressure dependent phase transitions.
This equation is solved numerically yielding the transition or the decomposition pressure.
When searching for a transition pressure, the final result depends on many variables such as the Hamiltonian used in the energy calculation (HF, LDA,...), the number of initial volume values considered, their distribution around the equilibrium volume or the function used to fit the E vs V data.
www.crystal.unito.it /tutojan2004/tutorials/H_phase/H_tut.html   (1969 words)

 Phase Transition Dynamics - Cambridge University Press   (Site not responding. Last check: 2007-10-20)
Phase transition dynamics is centrally important to current condensed matter physics.
The phase transition dynamics of real systems are discussed, treating interdisciplinary problems in a unified manner.
Phase Transition Dynamics provides a comprehensive account, building on the statistical mechanics of phase transitions covered in many introductory textbooks.
www.cambridge.org /catalogue/catalogue.asp?isbn=0521572932   (275 words)

 Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms : Nature   (Site not responding. Last check: 2007-10-20)
Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
These microscopic quantum fluctuations can induce a macroscopic phase transition in the ground state of a many-body system when the relative strength of two competing energy terms is varied across a critical value.
As the potential depth of the lattice is increased, a transition is observed from a superfluid to a Mott insulator phase.
www.nature.com /nature/journal/v415/n6867/abs/415039a.html   (250 words)

 Chemistry 103A; Sections 5, 6, 7, 8; Lecture 1; 21 Aug 00
Recall that phase diagram is p vs T graph which summarizes a great deal of information on the properties of substances.
On a phase diagram the space is divided into regions according to the state of the substance at each pressure and temperature.
A point where three phase lines meet is called a "triple point" because at this point, and only at a triple point, the three phases, in this case solid, liquid, and gas, can exist all at the same time in equilibrium with each other.
www.chem.arizona.edu /~salzmanr/103a004/nts004/l38/l38.html   (703 words)

 Third Phase Transition Could Help Explain Earthquakes
Phase transformations play an important role in the behavior of materials, since materials behave very differently in different forms, or phases.
But in their study, the Stony Brook scientists found that during a phase transition, a substructure of a material can transform by diffusionless transition -- even while the rest of the atoms in the material transform through short-range diffusion.
This type of transformation is distinct from either the diffusional or diffusionless transitions described in current solid state physics textbooks, and is named a pseudomartensitic transition.
unisci.com /stories/20012/0501013.htm   (485 words)

 Freezing into Unconsciousness
Instead of a gradual descent into unconsciousness, Steyn-Ross and her collaborators suspected that anesthesia actually induces a sudden phase transition between wakefulness and sleep, in the same way that chilled water freezes.
Physicists can tell exactly when the water-to-ice phase transition occurs because the typical separation of two molecules suddenly switches from zero--there is no characteristic separation of the randomly distributed liquid water molecules--to the distance between two molecules in ice's crystal lattice.
To test the phase transition hypothesis, Steyn-Ross used a detailed mathematical model created by Swinburne University of Technology's David Liley to simulate the electric currents exchanged by neurons in a millimeter-thick cylindrical column of the cortex called a macrocolumn.
focus.aps.org /story/v4/st30   (615 words)

 The Alder-Wainwright gas-solid phase transition.
T → 0 by undergoing a gas-solid phase transition at finite temperature and all pressures.
6, are shown the pressures of the Alder-Wainwright transition as determined by the vanishing of the system entropy as calculated both from the fluid phase alone, and also with inclusion of the contribution of the entropy of melting, as estimated from its low-temperature limit.  The data represented in Fig.
)  Similarly, previous investigators of the gas-solid phase transition restricted their considerations of stability conditions of the gas to the local behavior of the isothermal compressibility.  When all the requirements of stability are considered, the gas-solid phase transition appears naturally as a consequence of the vanishing of the absolute entropy of the fluid phase.
www.gasresources.net /Alder-WainwrightTransition.htm   (3912 words)

 Research at HP Labs : Information Dynamics Lab : Research Areas : Phase Transitions in Constraint Satisfaction Search
Many studies of constraint satisfaction problems have demonstrated, both empirically and theoretically, that easily computed structural parameters of these problems can predict, on average, how hard the problems are to solve by a variety of search methods.
This transition is analogous to phase transitions seen in some physical systems.
Phase transitions also appear in search algorithms for quantum computers using problem structure.
www.hpl.hp.com /shl/projects/constraints   (630 words)

 A Simple Phase Transition
Large fluctuations at the transition point are a typical characteristic of phase transitions.
As a consequence, attempts to evaluate behaviors near transitions with simulation experiments often require many more samples to accurately sample the typical range of behaviors than for parameter values far from transition points.
This simple example of a phase transition in a search problem can be extended to more complex situations where the number of solutions varies or the heuristic pruning effectiveness varies with depth [55].
www.hpl.hp.com /research/idl/projects/constraints/specialAIJ/node5.html   (787 words)

 Phase Transitions
The heat of phase transition is equal to the change of enthalpy.
On the P-T diagram phase transition occur along a line P(T).
If we move from phase I to phase II, thermodynamic potential G is continuous (why?), but its first derivative S jumps.
www.plmsc.psu.edu /~www/matsc597c-1997/phases/Lecture2/node2.html   (133 words)

 Response to Selection for the Timing of Vegetative Phase Transition in a Maize Population -- Revilla et al. 42 (5): ...
Vegetative phase change in sweet corn populations: genetics and relationships with agronomic traits (Vegetative phase change in open-pollinated sweet corn).
Phase identity of the maize leaf is determined after leaf initiation.
Vegetative phase change in maize and its association with resistance to fall armyworm.
crop.scijournals.org /cgi/content/full/42/5/1471   (2007 words)

 Simulate the liquid--to--gas phase transition of water   (Site not responding. Last check: 2007-10-20)
We are confronted daily with the phase transition from liquid to gas -- for example every time we boil water.
This interruption marks the phase transition from liquid to gas.
This ensures a lot of data points in the transition region to correctly show the behaviour of the system.
polymer.bu.edu /Wasser/robert/work/node13.html   (310 words)

 The Great Phase Transition: The Post-Oil Era
In moments of transition, the underlying laws we are accustomed to stop functioning and peculiar patterns emerge within our environment.
During the passage of water in liquid state to gas, the laws at work are no longer the laws of physics of the liquid state or those of its gaseous state.
This transition seems even more complex given the present phase of capitalism, which we might call senile, for it assumes a predatory character and an absolute irrationality concerning the ends (although it might appear rational in order to attain irrational ends).
globalresearch.ca /articles/FIG503A.html   (2964 words)

 [No title]
The study of phase transitions in combinatorial problems has a distinguished history, originating with the work of Erdös and Rényi on random graphs almost half a century ago.
In statistical mechanics terms, this may be understood as a phase transition, where the system undergoes a sudden change in microscopic order.
Theoretical arguments from the Satisfiability problem - which in certain cases exhibits a replica symmetry breaking (RSB) phase transition similar to that seen in spin glasses - indicate a connection between the nature of the transition and the problem's average-case algorithmic complexity.
www.ipam.ucla.edu /programs/ptac2002   (361 words)

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