Browsing Duke Faculty Articles by Subject "systems"

Now showing items 1-16 of 16

Active-Space N-Representability Constraints for Variational Two-Particle Reduced Density Matrix Calculations

Shenvi, Neil (AMER PHYSICAL SOC, 2010)

The ground-state energy of a system of fermions can be calculated by minimizing a linear functional of the two-particle reduced density matrix (2-RDM) if an accurate set of N-representability conditions is applied. In this ...
Application of Edwards' statistical mechanics to high-dimensional jammed sphere packings

Charbonneau, Patrick (AMER PHYSICAL SOC, 2010)

The isostatic jamming limit of frictionless spherical particles from Edwards' statistical mechanics [Song et al., Nature (London) 453, 629 (2008)] is generalized to arbitrary dimension d using a liquid-state description. ...
Bifurcation Analysis of Gene Regulatory Circuits Subject to Copy Number Variation

Mileyko, Yuriy (SIAM PUBLICATIONS, 2010)

Gene regulatory networks are comprised of many small gene circuits. Understanding expression dynamics of gene circuits for broad ranges of parameter space may provide insight into the behavior of larger regulatory networks ...
Conductance of quantum impurity models from quantum Monte Carlo

Liu, Dong E.; Chandrasekharan, Shailesh; Baranger, Harold (AMER PHYSICAL SOC, 2010)

The conductance of two Anderson impurity models, one with twofold and another with fourfold degeneracy, representing two types of quantum dots, is calculated using a world-line quantum Monte Carlo (QMC) method. Extrapolation ...
Magnetic Resonance Water Proton Relaxation in Protein Solutions and Tissue: T-1p Dispersion Characterization

Chen, Enn-Ling; Kim, Raymond (PUBLIC LIBRARY SCIENCE, 2010)

Background: Image contrast in clinical MRI is often determined by differences in tissue water proton relaxation behavior. However, many aspects of water proton relaxation in complex biological media, such as protein solutions ...
Making sense of health information technology implementation: A qualitative study protocol

Kitzmiller, Rebecca R.; Anderson, Ruth (BIOMED CENTRAL LTD, 2010)

Background: Implementing new practices, such as health information technology (HIT), is often difficult due to the disruption of the highly coordinated, interdependent processes (e. g., information exchange, communication, ...
Monte Carlo Study of the Axial Next-Nearest-Neighbor Ising Model

Zhang, Kai; Charbonneau, Patrick (AMER PHYSICAL SOC, 2010)

The equilibrium phase behavior of microphase-forming systems is notoriously difficult to obtain because of the extended metastability of the modulated phases. We develop a simulation method based on free-energy integration ...
Multiplexed Real-Time Polymerase Chain Reaction on a Digital Microfluidic Platform

Schell, Wiley; Benton, Jonathan L. (AMER CHEMICAL SOC, 2010)

This paper details the development of a digital microfluidic platform for multiplexed real-time polymerase chain reactions (PCR). Liquid samples in discrete droplet format are programmably manipulated upon an electrode ...
Neutron-deuteron analyzing power data at 19.0 MeV

Weisel, Gary; Tornow, Werner; Crowe, Benjamin III; Crowell, Dr Alexander; Esterline, J. H.; Howell, Calvin; Kelley, J. H.; Macri, Robert; Pedroni, Ronald; Walter, Richard (AMER PHYSICAL SOC, 2010)

Measurements of neutron-deuteron (n-d) analyzing power A(y)(theta) at E-n = 19.0 MeV are reported at 16 angles from theta(c.m.) = 46.7 to 152.0 degrees. The objective of the experiment is to better characterize the ...
Nonlinear piezoelectricity in electroelastic energy harvesters: Modeling and experimental identification

Stanton, Samuel C.; Mann, Dr Brian (AMER INST PHYSICS, 2010)

We propose and experimentally validate a first-principles based model for the nonlinear piezoelectric response of an electroelastic energy harvester. The analysis herein highlights the importance of modeling inherent ...
Platinum(II)-catalyzed intermolecular hydroamination of monosubstituted allenes with secondary alkylamines

Toups, Kristina L.; Widenhoefer, Ross (ROYAL SOC CHEMISTRY, 2010)

A 1 : 1 mixture of (dppf)PtCl2 and AgOTf (5 mol%) catalyzed the intermolecular hydroamination of monosubstituted allenes with secondary alkylamines at 80 degrees C to form allylic amines in good yield with selective formation ...
Reformulating time-dependent density functional theory with non-orthogonal localized molecular orbitals

Cui, Ganglong; Yang, Weitao (ROYAL SOC CHEMISTRY, 2010)

Time-dependent density functional theory (TDDFT) has broad application in the study of electronic response, excitation and transport. To extend such application to large and complex systems, we develop a reformulation of ...
Spin-state splittings, highest-occupied-molecular-orbital and lowest-unoccupied-molecular-orbital energies, and chemical hardness

Johnson, Erin; Yang, Weitao (AMER INST PHYSICS, 2010)

It is known that the exact density functional must give ground-state energies that are piecewise linear as a function of electron number. In this work we prove that this is also true for the lowest-energy excited states ...
Spontaneous brain activity as a source of ideal 1/f noise

West, Bruce J. (AMER PHYSICAL SOC, 2009)

We study the electroencephalogram (EEG) of 30 closed-eye awake subjects with a technique of analysis recently proposed to detect punctual events signaling rapid transitions between different metastable states. After ...
The Ultraviolet Absorption Coefficient of Melanosomes Decreases with Increasing Pheomelanin Content

Peles, Dana N.; Simon, John D. (AMER CHEMICAL SOC, 2010)

Uveal melanosomes from the iridal stroma contain both eumelanin and pheomelanin, the ratio of which varies with iris color. Herein, we report the absorption coefficient at lambda = 244 nm for individual human iridal stroma ...
Wielding the Wand without Facing the Music: Allowing Utilization Review Physicians to Trump Doctors' Orders, but Protecting them from the Legal Risk Ordinarily Attached to the Medical Degree

Record, Katherine L. (DUKE UNIV, 2010)

This Note identifies a discrepancy in the law governing the decisionmaking that directs patient care. Seeking treatment that a third party will pay for, a patient needs not only a physician-prescribed course of treatment ...