48 research outputs found

    Electron Oscillation-Based Mono-Color Gamma-Ray Source

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    Production of artificial gamma-ray source usually is a conception belonging to the category of experimental nuclear physics. Nuclear physicists achieve this goal through utilizing/manipulating nucleons, such as proton and neutron. Low-energy electrons are often taken as “by-products” when preparing these nucleons by ionizing atoms, molecules and solids, and high-energy electrons or β rays are taken as “wastage” generated in nuclear reaction. Utilization of those “by-products” has not won sufficient attention from the nuclear physics community. In this chapter, we point out a potential, valuable utilization of those “by-products.” Based on a universal principle of achieving powerful mono-color radiation source, we propose how to set up an efficient powerful electron-based gamma-ray source through available solid-state components/elements. Larger charge-to-mass ratio of an electron warrants the advantage of electron-based gamma-ray source over its nucleon-based counterpart. Our technique offers a more efficient way of manipulating nuclear matter through its characteristic EM stimulus. It can warrant sufficient dose/brightness/intensity and hence an efficient manipulation of nuclear matter. Especially, the manipulation of a nucleus is not at the cost of destroying many nuclei to generate a desired tool, that is, gamma ray with sufficient intensity, for achieving this goal. This fundamentally warrants a practical manipulation of more nuclei at desirable number

    Equivalent Nanocircuit Theory and Its Applications

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    A new methodology termed as equivalent nanocircuit (EN) theory is briefly introduced, and its recent important progress in designing meta‐material devices with peculiar characteristics in optical or infrared frequency domain is reviewed. Three representative EN‐based designs of infrared window meta‐materials, such as Butterworth filter, metal‐insulator‐metal absorber and design‐simplified TCO‐based super‐flat absorber, are demonstrated. All these progresses clearly indicate that the EN theory provides an inspiring advancement on the way of designing more complicated meta‐devices

    A modified FDTD algorithm for processing ultra-wide-band response

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    Finite-difference time-domain (FDTD) is an effective algorithm for resolving Maxwell equations directly in time domain. Although FDTD has obtained sufficient development, there still exists some improvement space for it, such as ultra-wide-band response and frequency-dependent nonlinearity. In order to resolve these troubles, a modified version of FDTD called complex-field frequency-decomposition (CFFD) FDTD method is introduced, in which the complex-field is adopted to eliminate pseudo-frequency components when computing nonlinearity and the frequency-decomposition is adopted to transform an ultra-wide-band response into a series of narrow-band responses when computing the interaction of ultra-short pulse with matters. Its successful applications in several typical situations and comparison with other methods sufficiently verify the uniqueness and superiority in processing ultra-wide-band response and frequency-dependent nonlinearity.Comment: 8 figure

    MVICS: a repository and search tool towards holistic semantic-based precise component selection.

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    Driven by the continuous expansions of software applications and the increases in component varieties and sizes, the so-called component mismatch problem has become a more severe hurdle for component selection and integration. Although many component repositories and search tools have been proposed, so far there is no satisfactory solution which simultaneously achieves the following goals: automated, semantic-based, and precise. This paper presents a novel component repository and associated search tool which implements holistic semantic-based and adaptation-aware component specification and retrieval. The repository and tool is based on a Multiple-View and Interrelated Component Specification ontology model (MVICS), which has a smooth integration with domain related software system ontologies. The MVICS provides a formally defined and ontology-based architecture to specify components automatically in a spectrum of perspectives. The integration enhances the function and application scope of the MVICS model by bringing domain semantics into component specification and retrieval. The repository and search tool contributes to the current state of the art with four unique features: ontology-based component specification mechanism, semantic-based component retrieval method, adaptive component matching, and a comprehensive result component profile. The repository and tool has been widely tested and evaluated via its online version and follow-on survey reports, which concluded that they are effective for avoiding the component mismatch problem and is promising for industrial use

    TDLE: 2-D LiDAR Exploration With Hierarchical Planning Using Regional Division

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    Exploration systems are critical for enhancing the autonomy of robots. Due to the unpredictability of the future planning space, existing methods either adopt an inefficient greedy strategy or require a lot of resources to obtain a global solution. In this work, we address the challenge of obtaining global exploration routes with minimal computing resources. A hierarchical planning framework dynamically divides the planning space into subregions and arranges their orders to provide global guidance for exploration. Indicators that are compatible with the subregion order are used to choose specific exploration targets, thereby considering estimates of spatial structure and extending the planning space to unknown regions. Extensive simulations and field tests demonstrate the efficacy of our method in comparison to existing 2D LiDAR-based approaches. Our code has been made public for further investigation.Comment: Accepted in IEEE International Conference on Automation Science and Engineering (CASE) 202

    MVICS: a repository and search tool towards holistic semantic-based precise component selection.

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    Driven by the continuous expansions of software applications and the increases in component varieties and sizes, the so-called component mismatch problem has become a more severe hurdle for component selection and integration. Although many component repositories and search tools have been proposed, so far there is no satisfactory solution which simultaneously achieves the following goals: automated, semantic-based, and precise. This paper presents a novel component repository and associated search tool which implements holistic semantic-based and adaptation-aware component specification and retrieval. The repository and tool is based on a Multiple-View and Interrelated Component Specification ontology model (MVICS), which has a smooth integration with domain related software system ontologies. The MVICS provides a formally defined and ontology-based architecture to specify components automatically in a spectrum of perspectives. The integration enhances the function and application scope of the MVICS model by bringing domain semantics into component specification and retrieval. The repository and search tool contributes to the current state of the art with four unique features: ontology-based component specification mechanism, semantic-based component retrieval method, adaptive component matching, and a comprehensive result component profile. The repository and tool has been widely tested and evaluated via its online version and follow-on survey reports, which concluded that they are effective for avoiding the component mismatch problem and is promising for industrial use

    Origin of Unexpected Low Energy Structure in Photoelectron Spectra Induced by Mid-Infrared Strong Laser Fields

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    Using a semiclassical model which incorporates tunneling and Coulomb field effects, the origin of the unexpected low-energy structure (LES) in above-threshold ionization spectrum observed in recent experiments [C. I. Blaga et al., Nature Phys. {\bf 5}, 335 (2009) and W. Quanet al., Phys. Rev. Lett. {\bf 103}, 093001 (2009)] is identified. We show that the LES arises due to an interplay between multiple forward scattering of an ionized electron and the electron momentum disturbance by the Coulomb field immediately after the ionization. The multiple forward scattering is mainly responsible for the appearance of LES, while the initial disturbance mainly determines the position of the LES peaks. The scaling laws for the LES parameters, such as the contrast ratio and the maximal energy, versus the laser intensity and wavelength are deduced

    Coulomb focusing at above-threshold ionization in elliptically polarized mid-infrared strong laser fields

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    The role of Coulomb focusing in above-threshold ionization in an elliptically polarized mid-infrared strong laser field is investigated within a semiclassical model incorporating tunneling and Coulomb field effects. It is shown that Coulomb focusing up to moderate ellipticity values is dominated by multiple forward scattering of the ionized electron by the atomic core that creates a characteristic low-energy structure in the photoelectron spectrum and is responsible for the peculiar energy scaling of the ionization normalized yield along the major polarization axis. At higher ellipticities, the electron continuum dynamics is disturbed by the Coulomb field effect mostly at the exit of the ionization tunnel. Due to the latter, the normalized yield is found to be enhanced, with the enhancement factor being sharply pronounced at intermediate ellipticities
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