arXiv subjects

Hong-Yu Chen

Publications and source records attributed to Hong-Yu Chen.

23 records · Page 2Linked to original sources

arXiv2015

Metal Oxide Resistive Memory using Graphene Edge Electrode

The emerging paradigm of abundant-data computing requires real-time analytics on enormous quantities of data collected by a mushrooming network of sensors. Todays computing technology, however, cannot scale to satisfy such big data applications with the required throughput and energy efficiency. The next technology frontier will be monolithically integrated chips with three dimensionally interleaved memory and logic for unprecedented data bandwidth with reduced energy consumption. In this work, we exploit the atomically thin nature of the graphene edge to assemble a resistive memory stacked in a vertical three dimensional structure. We report some of the lowest power and energy consumption among the emerging non-volatile memories due to an extremely thin electrode with unique properties, low programming voltages, and low current. Circuit analysis of the architecture using experimentally measured device properties show higher storage potential for graphene devices compared that of metal based devices.

cond-mat.mes-hall↗

arXiv2014

Meson exchange effects in elastic $ep$ scattering at loop level and the electromagnetic form factors of the proton

A new form of two-photon exchange(TPE) effect is studied to explain the discrepancy between unpolarized and polarized experimental data in elastic $ep$ scattering. The mechanism is based on a simple idea that apart from the usual TPE effects from box and crossed-box diagrams, the mesons may also be exchanged in elastic $ep$ scattering by two-photon coupling at loop level. The detailed study shows such contributions to reduced unpolarized cross section ($σ_{un}$) and polarized observables ($P_t,P_l$) at fixed $Q^2$ are only dependent on proton's electromagnetic form factors $G_{E,M}$ and a new unknown universal parameter $g$. After combining this contribution with the usual TPE contributions from box and crossed-box diagrams, the ratio $μ_pG_E/G_M$ extracted from the recent precise unpolarized and polarized experimental data can be described consistently.

hep-ph↗

arXiv2013

Possible Transit Timing Variations of the TrES-3 Planetary System

Five newly observed transit light curves of the TrES-3 planetary system are presented. Together with other light curve data from literature, 23 transit light curves in total, which cover an overall timescale of 911 epochs, have been analyzed through a standard procedure. From these observational data, the system's orbital parameters are determined and possible transit timing variations are investigated. Given that a null transit-timing-variation produces a fit with reduced chi^2=1.52, our results agree with previous work, that transit timing variations might not exist in these data. However, a 1-frequency oscillating transit-timing-variation model, giving a fit with a reduced chi^2=0.93, does possess a statistically higher probability. It is, thus, concluded that future observations and dynamical simulations for this planetary system will be very important.

astro-ph.EP↗

arXiv2013

Investigating Close-in Exoplanets through Transit Observations

Through the international collaborators, we recently established a network of existing and working meter-class telescopes to look for planetary transit events. As a first step, we focus on the TrES3 system, and conclude that there could be some level of transit timing variations.

astro-ph.EP↗

arXiv2011

Arithmetic Operations Beyond Floating Point Number Precision

In basic computational physics classes, students often raise the question of how to compute a number that exceeds the numerical limit of the machine. While technique of avoiding overflow/underflow has practical application in the electrical and electronics engineering industries, it is not commonly utilized in scientific computing, because scientific notation is adequate in most cases. We present an undergraduate project that deals with such calculations beyond a machine's numerical limit, known as arbitrary precision arithmetic. The assignment asks students to investigate the approach of calculating the exact value of a large number beyond the floating point number precision, using the basic scientific programming language Fortran. The basic concept is to utilize arrays to decompose the number and allocate finite memory. Examples of the successive multiplication of even number and the multiplication and division of two overflowing floats are presented. The multiple precision scheme has been applied to hardware and firmware design for digital signal processing (DSP) systems, and is gaining importance to scientific computing. Such basic arithmetic operations can be integrated to solve advanced mathematical problems to almost arbitrarily-high precision that is limited by the memory of the host machine.

physics.comp-ph↗