scholarly journals Hierarchical microphase separation in non-conserved active mixtures

2021 ◽  
Vol 44 (9) ◽  
Author(s):  
Yuting I. Li ◽  
Michael E. Cates
Keyword(s):  
Time Reversal ◽  
Microphase Separation ◽  
Equilibrium Phase ◽  
Reaction Rates ◽  
Leading Order ◽  
Free Energies ◽  
Active Model ◽  
Diffusive Dynamics ◽  
Break Time ◽  
New Type

AbstractNon-equilibrium phase separating systems with reactions, such as biomolecular condensates and bacteria colonies, can break time-reversal symmetry (TRS) in two distinct ways. Firstly, the conservative and non-conservative sectors of the dynamics can be governed by incompatible free energies; when both sectors are present, this is the leading-order TRS violation, captured in its simplest form by ‘Model AB’. Second, the diffusive dynamics can break TRS in its own right. This happens only at higher order in the gradient expansion (but is the leading behaviour without reactions present) and is captured by ‘Active Model B+’ (AMB+). Each of the two mechanisms can lead to microphase separation, by quite different routes. Here we introduce Model AB+, for which both mechanisms are simultaneously present, and show that for slow reaction rates the system can undergo a new type of hierarchical microphase separation, which we call ‘bubbly microphase separation’. In this state, small droplets of one fluid are continuously created and absorbed into large droplets, whose length-scales are controlled by the competing reactive and diffusive dynamics.

CVD Diamond Film Polishing Based on Accelerant Theory

2012 ◽  
Vol 497 ◽  
pp. 185-189
Author(s):  
Li Zhang ◽  
Shao Jie Ding ◽  
Dong Hui Wen ◽  
Zhen Hao Xu ◽  
Shi Ming Ji
Keyword(s):  
Diamond Film ◽  
High Efficiency ◽  
Low Cost ◽  
Cvd Diamond ◽  
Reaction Rates ◽  
Precision Machining ◽  
Key Technologies ◽  
Ultra Precision ◽  
New Type ◽  
Cvd Diamond Film

CVD diamond has become the mainstream trend for the development of diamond. Its ultra precision machining is one of the key technologies for expanding the application of CVD diamond film. The efficient polishing method is studied, called accelerant polishing technology, which can lower the activation energy needed in diamond graphitization by the accelerant action of transition metal. It accelerates reaction rates of graphitization and promotes the implementation of diamond’s removal mechanism. Experimentation results indicate that the polishing method is one new type of precision polishing technology with low cost and high efficiency.

Phase Diagram Calculation and Experimental Study on the New Type Mg-Al-Zn-Ca-Sr Alloy in the Mg-Rich Region

2010 ◽  
Vol 650 ◽  
pp. 246-252 ◽  
Author(s):  
Su Qin Luo ◽  
Ai Tao Tang ◽  
Fu Sheng Pan ◽  
Yi Chen ◽  
Zhong Xue Feng
Keyword(s):  
Phase Diagram ◽  
Equilibrium Phase ◽  
Solidification Process ◽  
Secondary Phase ◽  
Calculated Phase Diagram ◽  
Rich Region ◽  
Thermo Calc Software ◽  
Calculation Results ◽  
New Type ◽  
Equilibrium Phases

Calculated phase diagram reveals important phase details for a new type muti-component magnesium alloy. Isothermal sections at 25°C of Mg-Ca-Sr, , Mg-2.74Al-Ca-Sr, Mg-2.74Al-0.79Zn-Ca-Sr system in the Mg-rich region were calculated using CALPHAD method, Thermo-Calc software and Mg-Al-Zn-Ca-Sr quinary database. The equilibrium phase composition in the Mg-rich region was analyzed. The equilibrium phases and solidification process of Mg-2.74Al-0.79Zn-0.68Ca-0.03Sr quinary alloy was calculated. The calculation results were consistent with the experimental results of SEM-EDX analysis and DSC spectrum. The solidification process of Mg-2.74Al-0.79Zn-0.68Ca-0.03Sr quinary alloy is as follow : α-Mg precipitates at 621°C, secondary phase C15-Al2(Ca, Sr) and Gamma-Mg17Al12 precipitate at around 520°C and 160°C in sequence, A4B-(Al4Ca,Al4Sr) may precipitate at around 460°C.

A Simple Dislocation Theory of Melting

1977 ◽  
Vol 30 (6) ◽  
pp. 641 ◽  
Author(s):  
FD Stacey ◽  
RD Irvine
Keyword(s):  
Melting Point ◽  
Phase Boundary ◽  
Pressure Dependence ◽  
Equilibrium Phase ◽  
Perfect Crystal ◽  
Dislocation Theory ◽  
Free Energies ◽  
Clapeyron Equation ◽  
Volume Increment ◽  
Theory Of Melting

The ratio of volume increment to energy for the introduction of a simple dislocation to a crystal is used in the Clausius-Clapeyron equation to determine the pressure dependence of the equilibrium phase boundary between a perfect crystal and a completely dislocated crystal. It yields the Lindemann melting formula, which is thermodynamically valid for materials with central atomic forces in which melting involves no gross changes in coordination. It is concluded that melting is properly described as the free proliferation of dislocations and that melting point is the temperature at which the free energies of dislocations vanish.

Free energies

2021 ◽  
pp. 139-178
Author(s):  
James P. Sethna
Keyword(s):  
Molecular Motors ◽  
Degrees Of Freedom ◽  
Reaction Rates ◽  
Coarse Grained ◽  
Rate Theory ◽  
Free Energies ◽  
Reaction Rate Theory ◽  
The World ◽  
The Cost ◽  
Grand Canonical

Free energies ignore most of a system, to provide the emergent statistical ensemble describing things we care about. Free energies can ignore the external world. The cost of borrowing energy from the world is measured by the temperature, giving us the canonical ensemble and Helmholtz free energy. Similarly, borrowing particles and volume from the world gives us the grand canonical and Gibbs ensembles. Free energies can ignore unimportant internal degrees of freedom. These lead to friction and noise, and theories of chemical reactions and reaction rates. Free energies can be coarse-grained, removing short distances and times. Exercises apply free energies to molecular motors, thermodynamic relations, reaction rate theory, Zipf’s law for word frequencies, zombie outbreaks, and nucleosynthesis.

Thermodynamic Calculation of Bi-Au-Lu, Nd Ternary Systems

2016 ◽  
Vol 850 ◽  
pp. 444-451
Author(s):  
Shu Liang Wang ◽  
Lu Jiang Zhou ◽  
Jia Lian Li ◽  
Xiao Hong Wang ◽  
Yuan Hua Lin ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Intermetallic Compounds ◽  
Binary Systems ◽  
Ternary Systems ◽  
Free Energies ◽  
Gibbs Energies ◽  
Solution Models ◽  
New Type ◽  
Free Solder ◽  
Kister Equation

With available melting point and hardness, the Bi-based filler alloy is considered as one choice of high-temperature Pb-free solder. Phase diagram can play an important role in the design of new type of Pb-free solder.In the present work, the thermodynamic assessments of the Au-Nd and the Au-Lu binary systems have been carried out by the Calculation of Phase Diagram (CALPHAD) method based on the available experimental data. The Gibbs free energies of the solution phases were described by subregular solution models with the Redlich-Kister equation, and those of the intermetallic compounds were described by sublattice models. A set of self-consistent and reasonable thermodynamic parameters is obtained for the binary systems, which describes the Gibbs energies of the solution phases and the intermetallic compounds phases. Additionally, combined the reported Bi-Au, Bi-Lu and Bi-Nd binary systems, the thermodynamic database of the Bi-Au-Lu and the Bi-Au-Nd ternary systems have been developed, which will provide important thermodynamic information for the phase equilibria of the multicomponent Bi-based alloy systems.

Key Program for Non-Equilibrium Phase Diagram of Ni 1 Type Steel

2011 ◽  
Vol 204-210 ◽  
pp. 1357-1361 ◽  
Author(s):  
Qing Hua Zou ◽  
Sheng Zhong Zou
Keyword(s):  
Phase Diagram ◽  
Chemical Composition ◽  
Structural Steel ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Air Cooling ◽  
Lever Rule ◽  
Dynamic Phase ◽  
New Type ◽  
Non Equilibrium

The practical air-cooling new-type dynamic phase diagram and nonequilirium lever rule of Ni 1 structural steel was established, and the relevant structure and chemical composition were analyzed, which can be used in practical production. The computer programs for drawing binary non-equilibrium phase diagram of Ni type structural steel have designed.

scholarly journals Theory for rates, equilibrium constants, and Brønsted slopes in F1-ATPase single molecule imaging experiments

2015 ◽  
Vol 112 (46) ◽  
pp. 14230-14235 ◽  
Author(s):  
Sándor Volkán-Kacsó ◽  
Rudolph A. Marcus
Keyword(s):  
Ligand Binding ◽  
Single Molecule ◽  
Driving Forces ◽  
Equilibrium Constants ◽  
Reaction Rates ◽  
Exponential Dependence ◽  
Single Molecule Imaging ◽  
Free Energies ◽  
Coupled Reactions ◽  
Stall Angle

A theoretical model of elastically coupled reactions is proposed for single molecule imaging and rotor manipulation experiments on F1-ATPase. Stalling experiments are considered in which rates of individual ligand binding, ligand release, and chemical reaction steps have an exponential dependence on rotor angle. These data are treated in terms of the effect of thermodynamic driving forces on reaction rates, and lead to equations relating rate constants and free energies to the stalling angle. These relations, in turn, are modeled using a formalism originally developed to treat electron and other transfer reactions. During stalling the free energy profile of the enzymatic steps is altered by a work term due to elastic structural twisting. Using biochemical and single molecule data, the dependence of the rate constant and equilibrium constant on the stall angle, as well as the Børnsted slope are predicted and compared with experiment. Reasonable agreement is found with stalling experiments for ATP and GTP binding. The model can be applied to other torque-generating steps of reversible ligand binding, such as ADP and Pi release, when sufficient data become available.

A Thermodynamic Approach in Tuning Phase Stability in Nanocomposite Multilayers

2003 ◽  
Vol 788 ◽  
Author(s):  
G. B. Thompson ◽  
R. Banerjee ◽  
H. L. Fraser
Keyword(s):  
Functional Properties ◽  
Phase Stability ◽  
Volume Fraction ◽  
Stability Diagram ◽  
Free Energies ◽  
Two Phase ◽  
New Type ◽  
Interfacial Free Energies ◽  
Stabilizing Element ◽  
Good Agreement

ABSTRACTChanges in the crystallographic phase stability of individual layers in a multilayered thin film stack are expected to have a significant influence upon the functional properties of the structure. The ability to predict and tune these phase stability states is of relevant importance in order to maximize the functional properties of the multilayer. A classical thermodynamic methodology, based upon competitive volumetric and interfacial free energies, has been used in the prediction and subsequent confirmation of the hcp to bcc phase stability in a Ti/Nb multilayer. An outcome of this model is a new type of phase stability diagram that can be used to predict the hcp Ti and bcc Ti phase stability as a function of length scale and volume fraction. The Ti layers were subsequently alloyed with a bcc-stabilizing element. The alloyed sputtered deposited Ti layers were able to stabilize the bcc Ti phase to a larger layer thickness as compared to the unalloyed Ti/Nb multilayers. The percentage of alloying element added to the Ti layer in controlling the critical transition thickness between the two phase states had good agreement with the predictions proposed by the thermodynamic model.

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