Anomalous kinetics of attractive A+B→0A+B \to 0 reactions

We investigate the kinetics of $A+B \to 0$ reaction with the local attractive interaction between opposite species in one spatial dimension. The attractive interaction leads to isotropic diffusions inside segregated single species domains, and accelerates the reactions of opposite species at the domain boundaries. At equal initial densities of $A$ and $B$, we analytically and numerically show that the density of particles ($\rho$), the size of domains ($\ell$), the distance between the closest neighbor of same species ($\ell_{AA}$), and the distance between adjacent opposite species ($\ell_{AB}$) scale in time as $\rho \sim t^{-1/3}$, $\ell_{AA} \sim t^{1/3}$, and $\ell \sim \ell_{AB} \sim t^{2/3}$ respectively. These dynamical exponents form a new universality class distinguished from the class of uniformly driven systems of hard-core particles.Comment: 4 pages, 4 figure

Evidence for the Jacobi shape transition in hot 46Ti

The gamma-rays from the decay of the GDR in 46Ti compound nucleus formed in the 18O+28Si reaction at bombarding energy 105 MeV have been measured in an experiment using a setup consisting of the combined EUROBALL IV, HECTOR and EUCLIDES arrays. A comparison of the extracted GDR lineshape data with the predictions of the thermal shape fluctuation model shows evidence for the Jacobi shape transition in hot 46Ti. In addition to the previously found broad structure in the GDR lineshape region at 18-27 MeV caused by large deformations, the presence of a low energy component (around 10 MeV), due to the Coriolis splitting in prolate well deformed shape, has been identified for the first time.Comment: 8 pages, 4 figures, proceedings of the COMEX1 conference, June 2003, Paris; to be published in Nucl. Phys.

Ge/Si Quantum Dot Formation From Non-Uniform Cluster Fluxes

The controlled growth of ultra-small Ge/Si quantum dot (QD) nuclei (≈1 nm) suitable for the synthesis of uniform nanopatterns with high surface coverage, is simulated using atom-only and size non-uniform cluster fluxes. It is found that seed nuclei of more uniform sizes are formed when clusters of non-uniform size are deposited. This counter-intuitive result is explained via adatom-nanocluster interactions on Si(100) surfaces. Our results are supported by experimental data on the geometric characteristics of QD patterns synthesized by nanocluster deposition. This is followed by a description of the role of plasmas as non-uniform cluster sources and the impact on surface dynamics. The technique challenges conventional growth modes and is promising for deterministic synthesis of nanodot arrays.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56174/1/638_ftp.pd

Imaging Magnetic Focusing of Coherent Electron Waves

The magnetic focusing of electrons has proven its utility in fundamental studies of electron transport. Here we report the direct imaging of magnetic focusing of electron waves, specifically in a two-dimensional electron gas (2DEG). We see the semicircular trajectories of electrons as they bounce along a boundary in the 2DEG, as well as fringes showing the coherent nature of the electron waves. Imaging flow in open systems is made possible by a cooled scanning probe microscope. Remarkable agreement between experiment and theory demonstrates our ability to see these trajectories and to use this system as an interferometer. We image branched electron flow as well as the interference of electron waves. This technique can visualize the motion of electron waves between two points in an open system, providing a straightforward way to study systems that may be useful for quantum information processing and spintronics

Heat dissipation for power switches

Systems, methods, techniques and apparatuses of power switches are disclosed. One exemplary embodiment is a power switch comprising an outer housing; a power electronics board disposed within the housing and including a semiconductor switch structured to selectively conduct a current between a first power terminal and a second power terminal; a first heat sink coupled to the power electronics board; a plurality of thermally conductive connectors; a second heat sink coupled to the plurality of thermally conductive connectors, a control electronics board structured to control the semiconductor switch, the control electronics board being located within an enclosure formed of the second heat sink, the plurality of thermally conductive connectors, and the power electronics board

Solid state switching device including heat sinks and control electronics construction

A solid state switching device, such as a solid state circuit breaker, includes at least one heat sink, a control electronics printed circuit board (PCB), and power electronics. The power electronics are useful to regulate the flow of current from one terminal of the solid state switching device to another terminal. The power electronics can include one or more solid state devices such as FETs, Thyristors, Thyristors+ SiC JFET in parallel, IGBTs, and IGCTs. The control PCB can include a variety of circuit elements useful to perform the function of a gate driver useful to activate the solid state device of the power electronics. The control electronics can be positioned laterally to the power electronics and spanning from a heat sink positioned on one side of the power electronics to a heat sink positioned on an opposing side of the power electronics

Solid state switching device including nested control electronics

A solid state switching device, such as a solid state circuit breaker, includes at least one heat sink, a control electronics printed circuit board (PCB), and power electronics. The power electronics are useful to regulate the flow of current from one terminal of the solid state switching device to another terminal. The power electronics can include one or more solid state devices such as FETs, Thyristors, Thyristors+ SiC JFET in parallel, IGBTs, and IGCTs. The control PCB can include a variety of circuit elements useful to perform the function of a gate driver useful to activate the solid state device of the power electronics. The heat sink includes one or more signal vias formed therethrough to permit nesting of the control PCB within the heat sink