Thermal Logic Gates: Computation with phonons

Logic gates are basic digital elements for computers. We build up thermal logic gates that can perform similar operations as their electronic counterparts. The thermal logic gates are based on the nonlinear lattices, which exhibit very intriguing phenomena due to their temperature dependent power spectra. We demonstrate that phonons, the heat carriers, can be also used to carry information and processed accordingly. The possibility of nanoscale experiment is discussed.Comment: 5 pages, 5 figures. To appear in Phys. Rev. Let

Radiation-induced magnetoresistance oscillation in a two-dimensional electron gas in Faraday geometry

Microwave-radiation induced giant magnetoresistance oscillations recently discovered in high-mobility two-dimensional electron systems in a magnetic field, are analyzed theoretically. Multiphoton-assisted impurity scatterings are shown to be the primary origin of the oscillation. Based on a model which considers the interaction of electrons with the electromagnetic fields in Faraday geometry, we are able not only to reproduce the correct period, phase and the negative resistivity of the main oscillation, but also to obtain secondary peaks and additional maxima and minima in the resistivity curve, some of which were already observed in the experiments.Comment: 4 pages, 1 figure, revised version to be published in Phys. Rev. Let

Features and Partial Derivatives of Bertalanffy-Richards Growth Model in Forestry

The Bertalanffy-Richards growth model is employed more than any other models for forest growth and yield modelling. However, its features have not completely been recognised. As a result, misunderstanding of the model still appears in some papers published in forest journals. A study by [1] is cited here as an evidence of the misunderstanding. This paper tries to explain different features of the Bertalanffy-Richards growth model based on the different conditions of the allometric parameter and introduces an assessment software to easily get the partial derivatives with respect to each parameter when more complex techniques (e.g., the Marquardt method) are employed to estimate parameters of any nonlinear models. This paper indicates that [1] study appears some unreasonable evidences of nonlinear growth models from a forestry perspective

Natural convection in a triangular enclosure induced by solar radiation

Natural convection in a triangular enclosure induced by solar radiation is simulated and analyzed. The numerical simulation reveals three possible distinct flow regimes in the enclosure. It also reveals the variations of the dominant heat transfer mode and the flow status with the horizontal position along the wedge. The whole domain can be divided horizontally into several regions according to the dominant mode of heat transfer. For small Rayleigh numbers, heat transfer over the entire domain is dominated by conduction. For medium Rayleigh numbers, there are two distinct regions. Heat transfer in the near shore region is dominated by conduction. As the distance from the shore increases, stable convection becomes the dominant mode. The region dominated by stable convection expands with increasing Rayleigh number. For high Rayleigh numbers, the whole region can be divided into three distinct regions where the dominant mode of heat transfer changes from conduction to stable convection and then to unstable convection as the distance from the shore increases. The region of flow instability also expands with increasing Rayleigh number

Glassy Dynamics in a Frustrated Spin System: Role of Defects

In an effort to understand the glass transition, the kinetics of a spin model with frustration but no quenched randomness has been analyzed. The phenomenology of the spin model is remarkably similiar to that of structural glasses. Analysis of the model suggests that defects play a major role in dictating the dynamics as the glass transition is approached.Comment: 9 pages, 5 figures, accepted in J. Phys.: Condensed Matter, proceedings of the Trieste workshop on "Unifying Concepts in Glass Physics

Information Quality and Earnings Enhancement of the Bargain Purchase Gain

A bargain purchase gain arises for the acquiring company when the fair value of the acquired firm exceeds its purchase price. Since 2009, accounting standards require the excess to be immediately recognized as a bargain purchase gain in the acquiring company’s results of operations. This study examines such gains of non-financial firms covered by the SEC EDGAR database from 2009 to 2014. Our findings cast doubt on the informativeness of the reported bargain purchase gains and suggest that different companies may engage the bargain purchases for different reasons