Robust Simulations of Nanoscale Phase Change Memory: Dynamics and Retention

A robust simulation framework was developed for nanoscale phase change memory (PCM) cells. Starting from the reaction rate theory, the dynamic nucleation was simulated to capture the evolution of the cluster population. To accommodate the non-uniform critical sizes of nuclei due to the non-isothermal conditions during PCM cell programming, an improved crystallization model was proposed that goes beyond the classical nucleation and growth model. With the above, the incubation period in which the cluster distributions reached their equilibrium was captured beyond the capability of simulations with a steady-state nucleation rate. The implications of the developed simulation method are discussed regarding PCM fast SET programming and retention. This work provides the possibility for further improvement of PCM and integration with CMOS technology.

Reaction Rate Theory-Based Mathematical Approximation For The Amount Of Time It Takes For Cellular Respiration To Occur

The venerable process of cellular respiration is essential for cells to produce energy from glucose molecules, in order to carry out cellular work. The process is responsible for producing molecules of ATP, a molecule which is thermodynamically coupled with other biochemical and biophysical processes in order to provide energy for such processes to occur. While the process of cellular respiration is essential to biology, one cycle of the process occurs only in a matter of milliseconds, and so, it would be impractical to measure the time it takes for the process to occur through conventional means. Therefore, using concepts from reaction rate theory, particularly Marcus Theory of electron transfer, Michaelis-Menten kinetics for enzymatic catalysis, and the hard-sphere model of collision theory, I formulate and propose a mathematical approximation for the amount of time it takes forcellular respiration to occur. Through this heuristic approach, quantitatively knowing the amount of time it takes for one cycle of cellular respiration to occur could potentially have future applications in biological research.

Free energies

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.

Thermal Decomposition and Isomerization of Furfural and 2-Pyrone: A Theoretical Kinetic Study

We have studied the decomposition and isomerization of furfural in the gas-phase using quantum chemical and statistical reaction rate theory techniques. This work uncovers a variety of new reaction channels...

Thermal Decomposition Kinetics of Glyphosate (GP) and its Metabolite Aminomethylphosphonic Acid (AMPA)

Glyphosate (GP) is a widely used herbicide worldwide, yet accumulation of GP and its main byproduct, aminomethylphosphonic acid (AMPA), in soil and water has raised concerns about its potential effects to human health. Thermal treatment processes are one option for decontaminating material containing GP and AMPA, yet the thermal decomposition chemistry of these compounds remains poorly understood. Here, we have revealed the thermal decomposition mechanism of GP and AMPA by applying computational chemistry and reaction rate theory methods. <br>

Thermal Decomposition Kinetics of Glyphosate (GP) and its Metabolite Aminomethylphosphonic Acid (AMPA)

Glyphosate (GP) is a widely used herbicide worldwide, yet accumulation of GP and its main byproduct, aminomethylphosphonic acid (AMPA), in soil and water has raised concerns about its potential effects to human health. Thermal treatment processes are one option for decontaminating material containing GP and AMPA, yet the thermal decomposition chemistry of these compounds remains poorly understood. Here, we have revealed the thermal decomposition mechanism of GP and AMPA by applying computational chemistry and reaction rate theory methods. <br>

Thermal Decomposition Kinetics of Glyphosate (GP) and its Metabolite Aminomethylphosphonic Acid (AMPA)

Glyphosate (GP) is a widely used herbicide worldwide, yet accumulation of GP and its main byproduct, aminomethylphosphonic acid (AMPA), in soil and water has raised concerns about its potential effects to human health. Thermal treatment processes are one option for decontaminating material containing GP and AMPA, yet the thermal decomposition chemistry of these compounds remains poorly understood. Here, we have revealed the thermal decomposition mechanism of GP and AMPA by applying computational chemistry and reaction rate theory methods. <br>

Decomposition Kinetics of Perfluorinated Sulfonic Acids

A theoretical study of the decomposition kinetics of PFOS and other perfluorinated sulfonic acids, using density functional theory, wavefunction theory, and statistical reaction rate theory techniques.<br>

Decomposition Kinetics of Perfluorinated Sulfonic Acids

A theoretical study of the decomposition kinetics of PFOS and other perfluorinated sulfonic acids, using density functional theory, wavefunction theory, and statistical reaction rate theory techniques.<br>