245 research outputs found

    3D PROCESS MODELLING ON PERSONAL COMPUTERS

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    A method for reducing the computation needs of modellingcomplete fabrication processes for VLSI devices on personal computers in 3 dimensions, a treatment of equitations of basic physical processes, such as diffusion, oxidation, implantation, etching and deposition is presented. In the paper we will describe the structure of the TEDI (TechnologyDialog) program, the main formulas and principles of the models and some examples of 3D process simulation. The third part of the "TEDI" program (creating a set of control parameters, automatic simulation and graphical output of results) provides flexible possibilities of studyingthe connections between 1D, 2D and 3D simulations

    Large signal of h→μτh \rightarrow \mu \tau within the constraints of ei→ejγe_i \rightarrow e_j\gamma decays in the 3-3-1 model with neutral leptons

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    In the framework of the 3-3-1 model with neutral leptons, we have investigated the lepton-flavor-violating sources based on the Higgs mass spectrum which has two neutral Higgses identitied with corresponding ones in the Two-Higgs-Doublet model (THDM). On the 13 TeV13~\mathrm{TeV} scale of the LHC, we point out the parameter space regions where the experimental limits of ei→ejγe_i \rightarrow e_j\gamma decays are satisfied. These regions depend heavily on the mixing of exotic leptons but are predicted to have large h10→μτh^0_1\rightarrow \mu \tau signals. We also show that Br(h10→μτ)\mathrm{Br}(h^0_1\rightarrow \mu \tau) can reach a value of 10−410^{-4}.Comment: 30 pages, 9 figure

    A spatially and temporally localized sub-laser-cycle electron source

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    We present an experimental and numerical study of electron emission from a sharp tungsten tip triggered by sub-8 femtosecond low power laser pulses. This process is non-linear in the laser electric field, and the non-linearity can be tuned via the DC voltage applied to the tip. Numerical simulations of this system show that electron emission takes place within less than one optical period of the exciting laser pulse, so that an 8 fsec 800 nm laser pulse is capable of producing a single electron pulse of less than 1 fsec duration. Furthermore, we find that the carrier-envelope phase dependence of the emission process is smaller than 0.1% for an 8 fsec pulse but is steeply increasing with decreasing laser pulse duration.Comment: 4 pages, 5 figure

    One-loop contributions to decays eb→eaγe_b\to e_a \gamma and (g−2)ea(g-2)_{e_a} anomalies, and Ward identity

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    In this paper, we will present analytic formulas to express one-loop contributions to lepton flavor violating decays eb→eaγe_b\to e_a \gamma, which are also relevant to the anomalous dipole magnetic moments of charged leptons eae_a. These formulas were computed in the unitary gauge, using the well-known Passarino-Veltman notations. We also show that our results are consistent with those calculated previously in the 't Hooft-Veltman gauge, or in the limit of zero lepton masses. At the one-loop level, we show that the appearance of fermion-scalar-vector type diagrams in the unitary gauge will violate the Ward Identity relating to an external photon. As a result, the validation of the Ward Identity guarantees that the photon always couples with two identical particles in an arbitrary triple coupling vertex containing a photon.Comment: The version accepted to Nuclear Physics

    A Kalman Approach to Lunar Surface Navigation using Radiometric and Inertial Measurements

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    Future lunar missions supporting the NASA Vision for Space Exploration will rely on a surface navigation system to determine astronaut position, guide exploration, and return safely to the lunar habitat. In this report, we investigate one potential architecture for surface navigation, using an extended Kalman filter to integrate radiometric and inertial measurements. We present a possible infrastructure to support this technique, and we examine an approach to simulating navigational accuracy based on several different system configurations. The results show that position error can be reduced to 1 m after 5 min of processing, given two satellites, one surface communication terminal, and knowledge of the starting position to within 100 m

    The role of rainfalls for erosion and sedimentation in the degraded mangroves, Can Gio district, Vietnam

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    Joint Research on Environmental Science and Technology for the Eart

    Rare-earth monosulfides as durable and efficient cold cathodes

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    In their rocksalt structure, rare-earth monosulfides offer a more stable alternative to alkali metals to attain low or negative electron affinity when deposited on various III-V and II-VI semiconductor surfaces. In this article, we first describe the successful deposition of Lanthanum Monosulfide via pulsed laser deposition on Si and MgO substrates and alumina templates. These thin films have been characterized by X-ray diffraction, atomic force microscopy, high resolution transmission electron microscopy, ellipsometry, Raman spectroscopy, ultraviolet photoelectron spectroscopy and Kelvin probe measurements. For both LaS/Si and LaS/MgO thin films, the effective work function of the submicron thick thin films was determined to be about 1 eV from field emission measurements using the Scanning Anode Field Emission Microscopy technique. The physical reasons for these highly desirable low work function properties were explained using a patchwork field emission model of the emitting surface. In this model, nanocrystals of low work function materials having a orientation perpendicular to the surface and outcropping it are surrounded by a matrix of amorphous materials with higher work function. To date, LaS thin films have been used successfully as cold cathode emitters with measured emitted current densities as high as 50 A/cm2. Finally, we describe the successful growth of LaS thin films on InP substrates and, more recently, the production of LaS nanoballs and nanoclusters using Pulsed Laser Ablation.Comment: 61 pages, 24 figure
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