153 research outputs found
Efficient parallel mining of association rules on shared-memory multiple-processor machine
In this paper we consider the problem of parallel mining of association rules on a shared-memory multiprocessor system. Two efficient algorithms PSM and HSM have been proposed. PSM adopted two powerful candidate set pruning techniques distributed pruning and global pruning to reduce the size of candidates. HSM further utilized an I/O reduction strategy to enhance its performance. We have implemented PSM and HSM on a SGI Power Challenge parallel machine. The performance studies show that PSM and HSM out perform CD-SM, which is a shared-memory parallel version of the popular Apriori algorithm.published_or_final_versio
The Trapping and Characterization of a Single Hydrogen Molecule in a Continuously Tunable Nanocavity
Using inelastic electron tunneling spectroscopy with the scanning tunneling
microscope (STM-IETS) and density functional theory calculations (DFT), we
investigated properties of a single H2 molecule trapped in nanocavities with
controlled shape and separation between the STM tip and the Au (110) surface.
The STM tip not only serves for the purpose of characterization, but also is
directly involved in modification of chemical environment of molecule. The bond
length of H2 expands in the atop cavity, with a tendency of dissociation when
the gap closes, whereas it remains unchanged in the trough cavity. The
availability of two substantially different cavities in the same setup allows
understanding of H2 adsorption on noble metal surfaces and sets a path for
manipulating a single chemical bond by design.Comment: 11 pages, 4 figure
Application of Transmission Line Models to Backpanel Plated Through-Hole Via Design
This paper introduces an approach of using a plated through-hole (PTH) via transmission-line model in the design of a thick printed circuit board, such as a backpanel. Full wave FEM modeling of a section of backpanel containing a differential via pair was compared with a transmission model. Computed values of the differential transmission loss agreed within an acceptable range for engineering studies, yet the transmission line model results required less than 2% of the computation time that the full wave model required. Effects of via spacing, via diameter and trace thickness were also examined
Effects of Open Stubs Associated with Plated Through-Hole Vias in Backpanel Designs
Plated through-hole (PTH) vias are commonly used in printed circuit boards. They usually leave open stubs if the signal(s) does not transition the entire depth of the board. These open stubs can have a negative impact on signal transmission. This summary reports the investigation of the impact of the open via stubs in a typical backpanel design
A new method for assessing left atrial systolic function during isovolumetric atrial contraction in the intact heart: an animal study
Results on entire solutions for a degenerate critical elliptic equation with anisotropic coefficients
In this paper, we study the following degenerate critical elliptic equations
with anisotropic coefficients
where and Some basic properties of the degenerate
elliptic operator are investigated and some
regularity, symmetry and uniqueness results for entire solutions of this
equation are obtained. We also get some variational identities for solutions of
this equation. As a consequence, we obtain some nonexistence results for
solutions of this equation.Comment: 29 page
Rotational Spectromicroscopy: Imaging the Orbital Interaction between Molecular Hydrogen and an Adsorbed Molecule
A hydrogen molecule can diffuse freely on the surface and be trapped above an adsorbed molecule within the junction of a scanning tunneling microscope. The trapped dihydrogen exhibits the properties of a free rotor. Here we show that the intermolecular interaction between dihydrogen and Mg-porphyrin (MgP) can be visualized by imaging j=0 to 2 rotational excitation of dihydrogen. The interaction leads to a weakened H-H bond and modest electron donation from the dihydrogen to the lowest unoccupied molecular orbital of MgP, a process similarly observed for the interaction between dihydrogen and an adsorbed Au atom
Effects of redox mediators on the catalytic activity of iron porphyrins towards oxygen reduction in acidic media
The effects of different redox mediators on the oxygen reduction reaction (ORR) catalyzed by an iron porphyrin complex, iron(III) meso-tetra(N-methyl-4-pyridyl)porphine chloride [FeIIITMPyP], in 0.1 M triflic acid were investigated by cyclic voltammetry (CV) and spectroelectrochemistry in conjunction with density functional theory (DFT) calculations. The formal potentials of the FeIIITMPyP catalyst and the redox mediators, as well as the half-wave potentials for the ORR, were determined by CV in the absence and presence of oxygen in acidic solutions. UV/Vis spectroscopic and spectroelectrochemical studies confirmed that only the 2,2′-azino-bis(3-ethylbenzothiazioline-6-sulfonic acid)diammonium salt (C18H24N6O6S4) showed effective interactions with FeIIITMPyP during the ORR. DFT calculations suggested strong interaction between FeIIITMPyP and the C18H24N6O6S4 redox mediator. The redox mediator caused lengthening of the dioxygen iron bond, which thus suggested easier dioxygen reduction. Consistent results were observed in electrochemical impedance spectroscopic measurements for which the electron-transfer kinetics were also evaluated
Quantum Neuronal Sensing of Quantum Many-Body States on a 61-Qubit Programmable Superconducting Processor
Classifying many-body quantum states with distinct properties and phases of
matter is one of the most fundamental tasks in quantum many-body physics.
However, due to the exponential complexity that emerges from the enormous
numbers of interacting particles, classifying large-scale quantum states has
been extremely challenging for classical approaches. Here, we propose a new
approach called quantum neuronal sensing. Utilizing a 61 qubit superconducting
quantum processor, we show that our scheme can efficiently classify two
different types of many-body phenomena: namely the ergodic and localized phases
of matter. Our quantum neuronal sensing process allows us to extract the
necessary information coming from the statistical characteristics of the
eigenspectrum to distinguish these phases of matter by measuring only one
qubit. Our work demonstrates the feasibility and scalability of quantum
neuronal sensing for near-term quantum processors and opens new avenues for
exploring quantum many-body phenomena in larger-scale systems.Comment: 7 pages, 3 figures in the main text, and 13 pages, 13 figures, and 1
table in supplementary material
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