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Full-Text Articles in Physics

Shape Imprinting Due To Variable Disulfide Bonds In Polyacrylamide Gels, Andrew B. Greytak, Alexander Y. Grosberg, Toyoichi Tanaka Jun 2001

Shape Imprinting Due To Variable Disulfide Bonds In Polyacrylamide Gels, Andrew B. Greytak, Alexander Y. Grosberg, Toyoichi Tanaka

Faculty Publications

Through the use of variable disulfide crosslinkers, we have created polyacrylamide gels whose shape can be altered after polymerization. N,N'-bisacryloylcystamine is incorporated as a crosslinker, along with a smaller amount of a permanent crosslinker. After polymerization, the disulfide bonds are cleaved into thiols through reduction. By reoxidizing the thiols with the gel held in a new macroscopic shape, a new set of disulfide bonds is formed, and the gel is forced to adopt the new shape. Retension of the new shape improves with greater distortion from the original shape, as well as with increased concentration of variable …


Bistable Operation Of A Two-Section 1.3-Mm Inas Quantum Dot Laser—Absorption Saturation And The Quantum Confined Stark Effect, Xiaodong Huang, A. Stintz, Hua Li, Audra Rice, G. T. Liu, L.F. Lester, Julian Cheng, K.J. Malloy Mar 2001

Bistable Operation Of A Two-Section 1.3-Mm Inas Quantum Dot Laser—Absorption Saturation And The Quantum Confined Stark Effect, Xiaodong Huang, A. Stintz, Hua Li, Audra Rice, G. T. Liu, L.F. Lester, Julian Cheng, K.J. Malloy

Faculty Publications

Room temperature, continuous-wave bistability was observed in oxide-confined, two-section, 1.3- m quantum-dot (QD) lasers with an integrated intracavity quantum-dot saturable absorber. The origin of the hysteresis and bistability were shown to be due to the nonlinear saturation of the QD absorption and the electroabsorption induced by the quantum confined Stark effect.


Neutrino Reactions On The Deuteron, S. Nakamura, T. Sato, Vladimir Gudkov, K. Kubodera Feb 2001

Neutrino Reactions On The Deuteron, S. Nakamura, T. Sato, Vladimir Gudkov, K. Kubodera

Faculty Publications

The cross sections for the ν-d and ν̅ -d reactions are calculated for incident energy up to Eν=170 MeV with the use of a phenomenological Lagrangian approach. We assess and improve the reliability of the employed calculational method by examining the dependence of the results on various input and approximations that go into the calculation. The main points of improvement over the existing work are (1) use of the “modern” NN potentials, (2) use of the more accurate nucleon weak-interaction form factors, and (3) monitoring the strength of a vertex that governs the exchange-current contribution, with the use …


Diamagnetic Persistent Current In Diffusive Normal-Metal Rings, E. M.Q. Jariwala, P. Mohanty, M. B. Ketchen, Richard A. Webb Feb 2001

Diamagnetic Persistent Current In Diffusive Normal-Metal Rings, E. M.Q. Jariwala, P. Mohanty, M. B. Ketchen, Richard A. Webb

Faculty Publications

We have measured a diamagnetic persistent current with flux periodicities of both h/e and h/2e in an array of thirty diffusive mesoscopic gold rings. At the lowest temperatures, the magnitudes of the currents per ring corresponding to the h/e- and h/2e-periodic responses are both comparable to the Thouless energy Ecħ/τD, where τD is the diffusion time. Taken in conjunction with earlier experiments, our results strongly challenge the conventional theories of persistent current. We consider a new approach associated with the saturation of …


Quasirandom Distributed Gaussian Bases For Bound Problems, Sophya V. Garashchuk, J. C. Light Jan 2001

Quasirandom Distributed Gaussian Bases For Bound Problems, Sophya V. Garashchuk, J. C. Light

Faculty Publications

We introduce quasirandom distributed Gaussian bases (QDGB) that are well suited for bound problems. The positions of the basis functions are chosen quasirandomly while their widths and density are functions of the potential. The basis function overlap and kinetic energy matrix elements are analytical. The potential energy matrix elements are accurately evaluated using few-point quadratures, since the Gaussian basis functions are localized. The resulting QDGB can be easily constructed and is shown to be accurate and efficient for eigenvalue calculation for several multidimensional model vibrational problems. As more demanding examples, we used a 2D QDGB-DVR basis to calculate the lowest …


Semiclassical Application Of The Mo/Ller Operators In Reactive Scattering, Sophya V. Garashchuk, J. C. Light Jan 2001

Semiclassical Application Of The Mo/Ller Operators In Reactive Scattering, Sophya V. Garashchuk, J. C. Light

Faculty Publications

Mo/ller operators in the formulation of reaction probabilities in terms of wave packet correlation functions allow us to define the wave packets in the interaction region rather than in the asymptotic region of the potential surface. We combine Mo/ller operators with the semiclassical propagator of Herman and Kluk. This does not involve further approximations and can be used with any initial value representation (IVR) semiclassical propagator. Time propagation in asymptotic regions of the potential due to Mo/ller operators reduces the oscillations of the propagator integrand and improves convergence of the results with respect to the number of trajectories. The effectiveness …