Tel (Fax) : 02-958-XXXX
Title | : Optimal tuning of a confined Brownian information engine |
---|---|
Author | : Noh, Jae Dong,Lee, Jae Sung |
Journal | : PHYSICAL REVIEW E, 2016 |
NUMBER | Q17029 |
---|---|
AUTHOR | Noh, Jae Dong,Lee, Jae Sung |
TITLE | Optimal tuning of a confined Brownian information engine |
ARCHIVE | |
FILE | |
JOURNAL | PHYSICAL REVIEW E, 2016 |
ABSTRACT | A Brownian information engine is a device extracting mechanical work from a single heat bath by exploiting the information on the state of a Brownian particle immersed in the bath. As for engines, it is important to find the optimal operating condition that yields the maximum extracted work or power. The optimal condition for a Brownian information engine with a finite cycle time tau has been rarely studied because of the difficulty in finding the nonequilibrium steady state. In this study, we introduce a model for the Brownian information engine and develop an analytic formalism for its steady-state distribution for any tau. We find that the extracted work per engine cycle is maximum when t approaches infinity, while the power is maximum when t approaches zero. |
Title | : Scaling of cluster heterogeneity in percolation transitions |
---|---|
Author | : Noh, Jae Dong,Park, Hyunggyu |
Journal | : PHYSICAL REVIEW E, 2011 |
NUMBER | P11029 |
---|---|
AUTHOR | Noh, Jae Dong,Park, Hyunggyu |
TITLE | Scaling of cluster heterogeneity in percolation transitions |
ARCHIVE | arXiv:1106.0354 |
FILE | |
JOURNAL | PHYSICAL REVIEW E, 2011 |
ABSTRACT | We investigate a critical scaling law for the cluster heterogeneity H in site and bond percolations in d-dimensional lattices with d = 2,...,6. The cluster heterogeneity is defined as the number of distinct cluster sizes. As an occupation probability p increases, the cluster size distribution evolves from a monodisperse distribution to a polydisperse one in the subcritical phase, and back to a monodisperse one in the supercritical phase. We show analytically that H diverges algebraically, approaching the percolation critical point p(c) as H similar to vertical bar p - p(c)vertical bar(-1/sigma) with the critical exponent sigma associated with the characteristic cluster size. Interestingly, its finite-size-scaling behavior is governed by a new exponent v(H) = (1 + d(f)/d)v, where d(f) is the fractal dimension of the critical percolating cluster and v is the correlation length exponent. The corresponding scaling variable defines a singular path to the critical point. All results are confirmed by numerical simulations. |
Title | : Nonequilibrium fluctuations for linear diffusion dynamics |
---|---|
Author | : Noh, Jae Dong,Park, Hyunggyu |
Journal | : PHYSICAL REVIEW E, 2011 |
NUMBER | P11018 |
---|---|
AUTHOR | Noh, Jae Dong,Park, Hyunggyu |
TITLE | Nonequilibrium fluctuations for linear diffusion dynamics |
ARCHIVE | 1102.2973 |
FILE | |
JOURNAL | PHYSICAL REVIEW E, 2011 |
ABSTRACT | We present the theoretical study on nonequilibrium (NEQ) fluctuations for diffusion dynamics in high dimensions driven by a linear drift force. We consider a general situation in which NEQ is caused by two conditions: (i) drift force not derivable from a potential function, and (ii) diffusion matrix not proportional to the unit matrix, implying nonidentical and correlated multidimensional noise. The former is a well-known NEQ source and the latter can be realized in the presence of multiple heat reservoirs or multiple noise sources. We develop a statistical mechanical theory based on generalized thermodynamic quantities such as energy, work, and heat. The NEQ fluctuation theorems are reproduced successfully. We also find the time-dependent probability distribution function exactly as well as the NEQ work production distribution P(W) in terms of solutions of nonlinear differential equations. In addition, we compute low-order cumulants of the NEQ work production explicitly. In two dimensions, we carry out numerical simulations to check out our analytic results and also to get P(W). We find an interesting dynamic phase transition in the exponential tail shape of P(W), associated with a singularity found in solutions of the nonlinear differential equation. Finally, we discuss possible realizations in experiments. |
Title | : Deciphering Kinetic Information from Single-Molecule FRET Data That Show Slow Transitions |
---|---|
Author | : Hong, Seok-Cheol,Hyeon, Changbong |
Journal | : JOURNAL OF PHYSICAL CHEMISTRY B, 2015 |
NUMBER | C17037 |
---|---|
AUTHOR | Hong, Seok-Cheol,Hyeon, Changbong |
TITLE | Deciphering Kinetic Information from Single-Molecule FRET Data That Show Slow Transitions |
ARCHIVE | |
FILE | |
JOURNAL | JOURNAL OF PHYSICAL CHEMISTRY B, 2015 |
ABSTRACT | Single-molecule: FRET is One Of the most powerful and widely used biophysical techniques in biological sciences. It, however often suffers from limitations such as weak signal and limited measurement time intrinsic to single- Molecule fluorescence measurements. Despite several ameliorative measures taken to increase- measurement time, it is nearly impossible to acquire meaningful kinetic information on a molecule if conformational transitions of the molecule are ultraslow such that transition times ( |
Title | : Destabilization of i-Motif by Submolar Concentrations of a Monovalent Cation |
---|---|
Author | : Hong, Seok-Cheol,Hyeon, Changbong |
Journal | : JOURNAL OF PHYSICAL CHEMISTRY B, 2014 |
NUMBER | C15010 |
---|---|
AUTHOR | Hong, Seok-Cheol,Hyeon, Changbong |
TITLE | Destabilization of i-Motif by Submolar Concentrations of a Monovalent Cation |
ARCHIVE | |
FILE | |
JOURNAL | JOURNAL OF PHYSICAL CHEMISTRY B, 2014 |
ABSTRACT | Counterions are crucial for self-assembly of nucleic acids. Submolar monovalent cations are generally deemed to stabilize various types of base pairs in nucleic acids such as Watson-Crick and Hoogsteen base pairs via screening of electrostatic repulsion. Besides monovalent cations, acidic pH is required for i-motif formation because protons facilitate pairing between cytosines. Here we report that Li+ ions destabilize i-motif, whereas other monovalent cations, Na+ and K+, have the usual stabilizing effect. The thermodynamics data alone, however, cannot reveal which mechanism, enhanced unfolding or suppressed folding or both, is responsible for the Li+-induced destabilization. To gain further insight, we examined the kinetics of i-motif. To deal with slow kinetics of i-motif, we developed a method dubbed HaRP to construct a long FRET time trace to observe a sufficient number of transitions. Our kinetics analysis shows clearly that Li+ ions promote unfolding of i-motif but do not hinder its folding, lending strong support for our hypothesis on the origin of this unusual effect of Li+. Although the subangstrom size of Li+ ions allows them to infiltrate the space between cytosines in competition with protons, they cannot adequately fulfill the role of protons in mediating the hydrogen bonding of cytosine pairs. |