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Using LiF crystals for high-performance neutron imaging with micron-scale resolution

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High Power Laser Science and Engineering 2015年第4期3卷 1-9页

作者： A.Faenov m.matsubayashi T.Pikuz Y.Fukuda m.Kando R.Yasuda H.Iikura T.Nojima T.Sakai m.Shiozawa R.Kodama Y.Kato Institute for Academic Initiatives Suita Osaka University Joint Institute for High Temperatures Russian Academy of Sciences Quantum Beam Science Center Japan Atomic Energy Agency PPC and Graduate School of Engineering Suita Osaka University Nippon SOKEN Inc. The Graduate School for the Creation of New Photonics Industries

This paper describes an overview of our recent discovery – clear demonstration that Li F crystals can be efficiently used as a high-performance neutron imaging detector based on optically stimulated luminescence of color centers generated by neutron irradiation. It is shown that the neutron images we have obtained are almost free from granular noise, have a spatial resolution of～5.4 μm and a linear response with a dynamic range of at least 103. The high contrast and good sensitivity of Li F crystals allow us to distinguish two holes with less than 2% transmittance difference. We propose to use such detectors in areas where high spatial resolution with high image gradation resolution is needed, including diagnostics of different plasma sources such as laser and z-pinch produced plasmas.

关键词： color centers Li F crystals neutron imaging neutrons plasma diagnostics

Charged Noncommutative Wormhole Solutions via Power-Law f(T) models

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Communications in Theoretical Physics 2016年第10期65卷 411-422页

作者： Shamaila Rani Abdul Jawad m.Bilal Amin Department of mathematics COMSATS Institute of Information Technology

In this paper,we explore static spherically symmetric charged wormhole solutions in extended teleparallel gravity taking power-law f(T) *** consider noncommutative geometry under Lorentzian *** order to obtain matter components,we develop field equations using effective energy-momentum tensor for non-diagonal *** explore solutions by considering various viable power-law f(T) models,which also include teleparallel gravity *** violation of energy conditions obtain by exotic matter to form wormhole solutions in teleparallel case while,physical acceptable wormhole solutions exist for charged noncommutative wormhole solutions for some cases of power-law *** effective energy-momentum tensor and charge are responsible for the violation of the energy ***,we check the equilibrium condition for these *** equilibrium condition meets for the teleparallel case and some power-law solutions while remaining solutions are either in less equilibrium or in disequilibrium situation.

关键词： f(T) gravity wormhole Lorentzian distribution noncommutative geometry

Surface-type nonvolatile electric memory elements based on organic-on-organic CuPc-H_2Pc heterojunction

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Chinese Physics B 2015年第11期24卷 328-332页

作者： Khasan S.Karimov Zubair Ahmad Farid Touati m.mahroof-Tahir m.muqeet Rehman S.Zameer Abbas Ghulam Ishaq Khan Institute of Engineering Science and Technology Center for Innovative Development of Science and New Technologies Department of Electrical Engineering College of Engineering Qatar University Department of Chemistry and Earth Sciences Qatar University

A novel surface-type nonvolatile electric memory elements based on organic semiconductors CuPc and H2Pc are fabricated by vacuum deposition of the CuPc and H2Pc films on preliminary deposited metallic （Ag and Cu） electrodes. The gap between Ag and Cu electrodes is 3040μm. For the current-voltage （I-V） characteristics the memory effect, switching effect, and negative differential resistance regions are observed. The switching mechanism is attributed to the electric-field-induced charge transfer. As a result the device switches from a low to a high-conductivity state and then back to a low conductivity state if the opposite polarity voltage is applied. The ratio of resistance at the high resistance state to that at the low resistance state is equal to 120-150. Under the switching condition, the electric current increases -- 80-100 times. A comparison between the forward and reverse I-V characteristics shows the presence of rectifying behavior.

关键词： heterojunction nonvolatile memory organic-on-organic CuPc H2Pc

A minimizing Property of Homographic Solutions

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Acta mathematica Sinica,English Series 2014年第2期30卷 353-360页

作者： Abdalla m.mANSUR Daniel C.OFFIN Department of mathematics and Statistics Queen’s University

In this paper, we prove that the homographic solutions to the rhombus four body prob- lem are the variational minimizers of the Lagrangian action restricted on a holonomically constrained rhombus loop space.

关键词： Nbody problems holonomic systems action functional

Sparse-Grid Implementation of Fixed-Point Fast Sweeping WENO Schemes for Eikonal Equations

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Communications on Applied mathematics and Computation 2024年第1期6卷 3-29页

作者： Zachary m.miksis Yong-Tao Zhang Department of Applied and Computational mathematics and Statistics University of Notre DameNotre DameIN46556USA

Fixed-point fast sweeping methods are a class of explicit iterative methods developed in the literature to efficiently solve steady-state solutions of hyperbolic partial differential equations(PDEs).As other types of fast sweeping schemes,fixed-point fast sweeping methods use the Gauss-Seidel iterations and alternating sweeping strategy to cover characteristics of hyperbolic PDEs in a certain direction simultaneously in each sweeping *** resulting iterative schemes have a fast convergence rate to steady-state ***,an advantage of fixed-point fast sweeping methods over other types of fast sweeping methods is that they are explicit and do not involve the inverse operation of any nonlinear local ***,they are robust and flexible,and have been combined with high-order accurate weighted essentially non-oscillatory(WENO)schemes to solve various hyperbolic PDEs in the *** multidimensional nonlinear problems,high-order fixed-point fast sweeping WENO methods still require quite a large amount of computational *** this technical note,we apply sparse-grid techniques,an effective approximation tool for multidimensional problems,to fixed-point fast sweeping WENO methods for reducing their computational ***,we focus on fixed-point fast sweeping WENO schemes with third-order accuracy(Zhang et al.2006[41]),for solving Eikonal equations,an important class of static Hamilton-Jacobi(H-J)*** experiments on solving multidimensional Eikonal equations and a more general static H-J equation are performed to show that the sparse-grid computations of the fixed-point fast sweeping WENO schemes achieve large savings of CPU times on refined meshes,and at the same time maintain comparable accuracy and resolution with those on corresponding regular single grids.

关键词： Fixed-point fast sweeping methods Weighted essentially non-oscillatory(WENO)schemes Sparse grids Static Hamilton-Jacobi(H-J)equations Eikonal equations

Chemical speciation,bioavailability and risk assessment of potentially toxic metals in soils around petroleum product marketing company as environmental degradation indicators

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Petroleum Research 2022年第2期7卷 286-296页

作者： Festus m.Adebiyi Dayo A.Ayeni Dangote Oil Refinery Company Ltd. 1Alfred Rewane RoadFalomoIkoyiLagosNigeria Department of Chemistry Obafemi Awolowo UniversityIle-IfeNigeria

The study aims at investigating chemical speciation,bioavailability and risk assessment of some selected metals in soils around refined petroleum depot using the concentrations of the metals as variables to ascertain the impacts of the activities within the petroleum ***-soils(0e15 cm)were collected from within the premises of Pipelines and Product marketing Company,Ibadan,Nigeria,while control samples were collected at 200 m away from the study *** conductivity and pH were measured using a calibrated dual purpose meter,while elemental analysis was done using Atomic absorption spectroscopy analytical *** results showed that the soils exhibited low ecological risk;minor enrichment for mn,moderately severe enrichment for Ni and Co,severe enrichment for Cr and extremely severe enrichment for Pb,Zn and *** was low contamination factor for Pb,Ni,mn,Cr,Co,and Fe and moderate contamination by Zn and ***-accumulation index results indicated unpolluted with Ni,mn,Cr,Co,and Fe,unpolluted to moderately polluted with Pb and Zn and moderately to strongly polluted with ***-element clustering results indicated chemical affinity and/or similar genetic origin among the *** analysis suggested that Fe,Co,Cr,Cd,and Ni occurred in the residual fraction;Pb,and Zn in the carbonate fraction,while mn have its highest percentage in the Fe emn oxides *** mobility and bioavailability showed that most of the metals are immobile and *** concluded that the oil-impacted soils were contaminated with most of the metals,but with low ecological risk.

关键词： Atomic absorption spectrometry Chemical speciation metals Refined petroleum product Risk assessment Soil

Projection on Segre varieties and determination of holomorphic mappings between real submanifolds Dedicated to Professor Sheng GONG on the occasion of his 75th birthday

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Science China mathematics 2006年第11期49卷 1611-1624页

作者： BAOUENDI m S EBENFELT Peter ROTHSCHILD Linda P Department of mathematics University of California at San Diego La JollaCA 92093-0112USA

It is shown that a germ of a holomorphic mapping sending a real-analytic generic submanifold of finite type into another is determined by its projection on the Segre variety of the target manifold. A necessary and sufficient condition is given for a germ of a mapping into the Segre variety of the target manifold to be the projection of a holomorphic mapping sending the source manifold into the target. An application to the biholomorphic equivalence problem is also given.

关键词： Segre variety, generic submanifold, Segre mappings, finite type, biholomorphic equivalence.

Dehydration Kinetics of Embryonic Axes from Desiccation-sensitive Seeds:An Assessment of Descriptive models

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Journal of Integrative Plant Biology 2009年第11期51卷 1002-1007页

作者： Tobias m. Ntuli Norman W. Pammenter School of Biological and Conservation Sciences University of KwaZulu-NatalWestville Campus

The response of desiccation-sensitive plant tissues to dehydration is significantly affected by dehydration conditions, particularly the rate of drying. Consequently it is important to be able to quantify drying rate. The aim of the study was to assess two models that have been proposed to describe drying kinetics, and thus to provide a quantification of non-linear drying rates, of embryonic axes excised from recalcitrant seeds. These models are an exponential drying time course, and a modified inverse relationship, respectively. For the six species investigated here the inverse function was generally found to fit drying data better than the exponential function under both rapid and slow drying conditions, and so is recommended. The rate of drying, under the conditions used here, was determined by axis size and possibly the nature of the axis outer coverings, rather than the water activity difference between the tissue and surrounding air.

关键词： desiccation drying rate recalcitrant seeds.

magnetic and superconducting phase diagrams and transition temperatures predicted using text mining and machine learning

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npj Computational materials 2020年第1期6卷 1521-1529页

作者： Callum J.Court Jacqueline m.Cole Cavendish Laboratory Department of PhysicsUniversity of CambridgeJ.J.Thomson AvenueCambridge CB30HEUK ISIS Neutron and muon Source STFC Rutherford Appleton LaboratoryHarwell Science and Innovation CampusDidcotOxfordshire OX110QXUK Argonne National Laboratory 9700 South Cass AvenueArgonneIL 60439USA Department of Chemical Engineering and Biotechnology University of CambridgeWest Cambridge SitePhilippa Fawcett DriveCambridge CB30FSUK

Predicting the properties of materials prior to their synthesis is of great importance in materials *** and superconducting materials exhibit a number of unique properties that make them useful in a wide variety of applications,including solid oxide fuel cells,solid-state refrigerants,photon detectors and metrology *** all these applications,phase transitions play an important role in determining the feasibility of the materials in ***,we present a pipeline for fully integrating data extracted from the scientific literature into machine-learning tools for property prediction and materials *** advanced natural language processing(NLP)and machine-learning techniques,we successfully reconstruct the phase diagrams of well-known magnetic and superconducting compounds,and demonstrate that it is possible to predict the phase-transition temperatures of compounds not present in the *** provide the tool as an online open-source platform,forming the basis for further research into magnetic and superconducting materials discovery for potential device applications.

关键词： phase transition superconducting