1,923 research outputs found

    MGOS: A library for molecular geometry and its operating system

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    The geometry of atomic arrangement underpins the structural understanding of molecules in many fields. However, no general framework of mathematical/computational theory for the geometry of atomic arrangement exists. Here we present "Molecular Geometry (MG)'' as a theoretical framework accompanied by "MG Operating System (MGOS)'' which consists of callable functions implementing the MG theory. MG allows researchers to model complicated molecular structure problems in terms of elementary yet standard notions of volume, area, etc. and MGOS frees them from the hard and tedious task of developing/implementing geometric algorithms so that they can focus more on their primary research issues. MG facilitates simpler modeling of molecular structure problems; MGOS functions can be conveniently embedded in application programs for the efficient and accurate solution of geometric queries involving atomic arrangements. The use of MGOS in problems involving spherical entities is akin to the use of math libraries in general purpose programming languages in science and engineering. (C) 2019 The Author(s). Published by Elsevier B.V

    Economical Auto Moment Limiter for Preventing Mobile Cargo Crane Overload

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    This study presents a computational method called economical auto moment limiter (eAML) that prevents a mobile cargo crane from being overloaded. The eAML detects and controls, in real time, crane overload without using boom stroke sensors and load cells, which are expensive items inevitable to existing AML systems, hence, being competitive in price. It replaces these stroke sensors and load cells that are used for the crane overload measurement with a set of mathematical formula and control logics that calculates the lifting load being handled under crane operation and the maximum lifting load. By calculating iterative them using only a pressure sensor attached under the derrick cylinder and the boom angle sensor, the mathematical model identifies the maximum descendible angle of the boom. The control logic presents the control method for preventing the crane overload by using the descendible angle obtained by the mathematical model. Both the mathematical model and the control logic are validated by rigorous simulation experiments using MATLAB on two case instances each of which eAML is used and not used, while changing the pressures on the derrick cylinder and the boom angle. The effectiveness and validity of the method are confirmed by comparing the outputs obtained by the controlled experiments performed by using a 7.6 ton crane on top of SCS887 and a straight-type maritime heavy-duty crane along with eAML. The effects attributed to the load and the wind speed are quantified to verify the reliability of eAML under the changes in external variables. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.1

    Acute Interstitial Pneumonia in Siblings: A Case Report

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    Acute interstitial pneumonia (AIP) is a rapidly progressive condition of unknown cause that occurs in a previously healthy individual and produces the histologic findings of diffuse alveolar damage. Since the term AIP was first introduced in 1986, there have been very few case reports of AIP in children. Here we present a case of AIP in a 3-yr-old girl whose other two siblings showed similar radiologic findings. The patient was confirmed to have AIP from autopsy showing histological findings of diffuse alveolar damage and proliferation of fibroblasts. Her 3-yr-old brother was also clinically and radiologically highly suspected as having AIP, and the other asymptomatic 8-yr-old sister was radiologically suspected as having AIP

    Boundary integral equation method for resonances in gradient index cavities designed by conformal transformation optics

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    In the case of two-dimensional gradient index cavities designed by the conformal transformation optics, we propose a boundary integral equation method for the calculation of resonant mode functions by employing a fictitious space which is reciprocally equivalent to the physical space. Using the Green's function of the interior region of the uniform index cavity in the fictitious space, resonant mode functions and their far-field distributions in the physical space can be obtained. As a verification, resonant modes in lima\c{c}on-shaped transformation cavities were calculated and mode patterns and far-field intensity distributions were compared with those of the same modes obtained from the finite element method.Comment: 13 pages, 6 figure

    Violet-light spontaneous and stimulated emission from ultrathin In-rich InGaN/GaN multiple quantum wells grown by metalorganic chemical vapor deposition

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    We investigated the spontaneous and stimulated emission properties of violet-light-emitting ultrathin In-rich InGaN/GaN multiple quantum wells (MQWs) with indium content of 60%-70%. The Stokes shift was smaller than that of In-poor InGaN MQWs, and the emission peak position at 3.196 eV was kept constant with increasing pumping power, indicating negligible quantum confined Stark effect in ultrathin In-rich InGaN MQWs despite of high indium content. Optically pumped stimulated emission performed at room temperature was observed at 3.21 eV, the high-energy side of spontaneous emission, when the pumping power density exceeds ???31 kW/ cm2.open6
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