Study on spontaneous emission in complex multilayered plasmonic system via surface integral equation approach with layered medium Green's function

A rigorous surface integral equation approach is proposed to study the spontaneous emission of a quantum emitter embedded in a multi-layered plasmonic structure with the presence of arbitrarily shaped metallic nanoscatterers. With the aid of the Fermi's golden rule, the spontaneous emission of the emitter can be calculated from the local density of states, which can be further expressed by the imaginary part of the dyadic Green's function of the whole electromagnetic system. To obtain this Green's function numerically, a surface integral equation is established taking into account the scattering from the metallic nanoscatterers. Particularly, the modeling of the planar multilayered structure is simplified by applying the layered medium Green's function to reduce the computational domain and hence the memory requirement. Regarding the evaluation of Sommerfeld integrals in the layered medium Green's function, the discrete complex image method is adopted to accelerate the evaluation process. This work offers an accurate and efficient simulation tool for analyzing complex multilayered plasmonic system, which is commonly encountered in the design of optical elements and devices. © 2012 Optical Society of America.published_or_final_versio

Multi-variable thermal modeling of power devices considering mutual coupling

© 2019 by the authors. In relation to power converter design, power density is increasing while the form factor is decreasing. This trend generally reduces the rate of the cooling process, which increases the mutual thermal coupling among the surrounding power components. Most of the traditional models usually ignore the mutual effects or just focus on the conduction coupling. To deal with these factors, the thermal modeling for a boost converter system has been built to compare the junction temperatures (Tj) and the increments under different working conditions in order to consider the conduction coupling. A multi-variable thermal resistances model is proposed in this paper to incorporate the convection thermal coupling into the mutual thermal effects. The coupling resistances, MOSFET to the diode (Rcp-DM ⇀), and the diode to MOSFET (Rcp-DM ⇀) have been calculated and the relationships between coupling resistances and their impact factors (separation distances and working currents) have been discussed. New case temperatures (Tc) obtained by calculation and additional measurements at other separation distances serve to verify the efficacy of the proposed model. This model enhances the current thermal models and provides an effective method to calculate the thermal coupling resistances which can be used to estimate the Tj. As the coupling resistances are distance dependent, the model also helps to optimize and fine-tune the placements of components in high-power density converters

Experimental study of subcooled flow boiling heat transfer on micro-pin-finned surfaces in short-term microgravity

The flow boiling heat transfer of subcooled air-dissolved FC-72 on micro-pin-finned surfaces was studied in microgravity by utilizing the drop tower facility in Beijing. The micro-pin-fins with the dimension of 30 x 30 x 60 mu m(3) (width x thickness x height), named PF30-60, were fabricated on a silicon chip by using the dry etching technique. For comparison, experiments of flow boiling heat transfer in terrestrial gravity were also conducted. The effects of inlet velocity on both flow boiling heat transfer and bubble behavior were explored. It was found that gravity has nearly no effect on flow boiling heat transfer for the departure of the inertial-force dominant bubbles in the low and moderate heat fluxes regions. In contrast, in the high-heat-flux region, the flow boiling heat transfer deteriorates and the critical heat flux (CHF) decreases due to the bubble accumulation in the channel. For PF30-60 at V = 0.5 m/s, the CHF point can be inferred to be between 20.8 and 24.5 W/cm(2), which is 63.0-74.2% of that in normal gravity. Regarding PF30-60 at V = 1.0 m/s, the CHF point can be inferred to be between 25.4 and 31.6 W/cm(2), which is 67.6-84.0% of that in normal gravity. The impact of gravity on CHF is closely linked to the channel geometry parameter and surface modification. The dimensionless numbers, Ch (Channel number) and Sf (Surface number), were proposed to describe the effect of the channel geometry and surface modification on the ratio of CHF in microgravity to that in normal gravity (CHF mu g/CHF1g). An empirical correlation based on We (Weber number), Ch and Sf was proposed to predict the value of CHF mu g/CHF1g ratio in good agreement with the experimental data. This study provides a new perspective to determine the threshold inlet velocity of inertial-force-dominant flow boiling under different experimental conditions at different gravity levels

EFFECT OF STRUCTURAL RELAXATION ON THE DEFORMATION BEHAVIOR OF A Zr64.13Cu15.75Ni10.12Al10 BULK METALLIC GLASS UNDER NANOINDENTATION

Structural relaxation by isothermal annealing below the glass transition temperature is conducted on a Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass. The effect of structural relaxation on thermal and mechanical properties was investigated by differential scanning calorimetry and instrumented nanoindentation. The recovery of the enthalpy in the DSC curves indicates that thermally unstable defects were annihilated through structural relaxation. During nanoindentation, the structural relaxation did not have a significant influence on the serrated plastic flow behavior. However, Structural relaxation shows an obvious effect in increasing both the hardness and elastic modulus, which is attributed to the annihilation of thermally unstable defects that resulted from the relaxation

Transfer learning with large-scale data in brain-computer interfaces

© 2016 IEEE. Human variability in electroencephalogram (EEG) poses significant challenges for developing practical real-world applications of brain-computer interfaces (BCIs). The intuitive solution of collecting sufficient user-specific training/calibration data can be very labor-intensive and time-consuming, hindering the practicability of BCIs. To address this problem, transfer learning (TL), which leverages existing data from other sessions or subjects, has recently been adopted by the BCI community to build a BCI for a new user with limited calibration data. However, current TL approaches still require training/calibration data from each of conditions, which might be difficult or expensive to obtain. This study proposed a novel TL framework that could nearly eliminate requirement of subject-specific calibration data by leveraging large-scale data from other subjects. The efficacy of this method was validated in a passive BCI that was designed to detect neurocognitive lapses during driving. With the help of large-scale data, the proposed TL approach outperformed the within-subject approach while considerably reducing the amount of calibration data required for each individual (∼1.5 min of data from each individual as opposed to a 90 min pilot session used in a standard within-subject approach). This demonstration might considerably facilitate the real-world applications of BCIs

A unified Hamiltonian solution to Maxwell-Schrodinger equations for modeling electromagnetic field-particle interaction

A novel unified Hamiltonian approach is proposed to solve Maxwell–Schrödinger equation for modeling the interaction between classical electromagnetic (EM) fields and particles. Based on the Hamiltonian of electromagnetics and quantum mechanics, a unified Maxwell–Schrödinger system is derived by the variational principle. The coupled system is well-posed and symplectic, which ensures energy conserving property during the time evolution. However, due to the disparity of wavelengths of EM waves and that of electron waves, a numerical implementation of the finite-difference time-domain (FDTD) method to the multiscale coupled system is extremely challenging. To overcome this difficulty, a reduced eigenmode expansion technique is first applied to represent the wave function of the particle. Then, a set of ordinary differential equations (ODEs) governing the time evolution of the slowly-varying expansion coefficients are derived to replace the original Schrödinger equation. Finally, Maxwell’s equations represented by the vector potential with a Coulomb gauge, together with the ODEs, are solved self-consistently. For numerical examples, the interaction between EM fields and a particle is investigated for both the closed, open and inhomogeneous electromagnetic systems. The proposed approach not only captures the Rabi oscillation phenomenon in the closed cavity but also captures the effects of radiative decay and shift in the open free space. After comparing with the existing theoretical approximate models, it is found that the approximate models break down in certain cases where a rigorous self-consistent approach is needed. This work is helpful for the EM simulation of emerging nanodevices or next-generation quantum electrodynamic systems

Review of multi-scale electromagnetic modeling

This paper reviews various methods to solve multiscale problems ranging from low-frequency methods to very high-frequency methods. ©2010 IEEE.published_or_final_versionThe 2010 International Conference on Electromagnetics in Advanced Applications (ICEAA), Sydney, N.S.W., 20-24 September 2010. In Proceedings of ICEAA'10, 2010, p. 641-64

Genetic ME-a visualization application for merging and editing pedigrees for genetic studies Medical Informatics and Decision Making

Background: In order to study the genetics of diseases more accurately and effectively, one often collects large families. Different members of a large family may provide differing information about the structure and make-up of their pedigree. Thus, software is needed to facilitate reconciliation of pedigrees collected independently from multiple informants from a single large family to create a unified pedigree that is based on the best composite information available. Findings: Our implementation demonstrates that Genetic ME performs merging in terms of adding, replacing and combining information from two pedigrees. Through a tracking process, all of the changes made to the data set for the individuals can be traced back to their original source material. A new pedigree structure can be easily visualized while reconciling disparate information from multiple pedigrees. Methods: We developed the Genetic Merging & Editing (Genetic ME) program, an open source Java application built on top of CraneFoot and Ghostscript, to support comparing, editing and merging of pedigrees collected from multiple sources in a visually-oriented manner. Conclusions: Genetic ME constitutes an ideal addition to software packages for reconciling pedigree information from multiple sources. Genetic ME provides a friendly graphical user interface, traces the changes made by users, and produces viewable merged pedigree structures able to be further used by other popular analysis programs

STK295900, a Dual Inhibitor of Topoisomerase 1 and 2, Induces G<inf>2</inf> Arrest in the Absence of DNA Damage

STK295900, a small synthetic molecule belonging to a class of symmetric bibenzimidazoles, exhibits antiproliferative activity against various human cancer cell lines from different origins. Examining the effect of STK295900 in HeLa cells indicates that it induces G2 phase arrest without invoking DNA damage. Further analysis shows that STK295900 inhibits DNA relaxation that is mediated by topoisomerase 1 (Top 1) and topoisomerase 2 (Top 2) in vitro. In addition, STK295900 also exhibits protective effect against DNA damage induced by camptothecin. However, STK295900 does not affect etoposide-induced DNA damage. Moreover, STK295900 preferentially exerts cytotoxic effect on cancer cell lines while camptothecin, etoposide, and Hoechst 33342 affected both cancer and normal cells. Therefore, STK295900 has a potential to be developed as an anticancer chemotherapeutic agent. © 2013 Kim et al