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KCl:Eu^(2+) as a solar UV-C radiation dosimeter. Optically stimulated luminescence and thermoluminescence analyses

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Journal of Rare Earths 2009年第4期27卷 579-583页

作者： I.Aguirre de Cárcer H.L.d'Antoni m.Barboza-Flores V.Correcher F.Jaque departamento Física de materiales Universidad Autónoma Madrid Spain NASA Ames Research Center Moffett Field California USA Centro de Investig ción en Física Universidad de Sonora México Centro Investigaciones Energía y medioambientales (CIEmAT) madrid Spain

The KCI：Eu2＋ system response to UV-C was investigated by analyzing the optically stimulated luminescence （OSL） and ther- mo-luminescence （TL） signal produced by ultraviolet light exposure at room temperature. It was found that after UV-C ***, OSL was produced on a wide band of visible wavelengths with decay time that varied by several orders of magnitude depending on the Eu2＋ aggregation state. In spite of the low intensity of solar UV-C reaching the Earth＇s surface in madrid （40° N, 700 m a.s.1.）, it was possible to measure the UV-C radiation dose at 6：48 solar time by using the TL response of the KCI：Eu2＋ system and differentiate it from the ambient beta radiation dose.

关键词： thermo-luminescence rare-earth-doped alkali halides solar ultraviolet dosimeter environmental radiation

Analysis of turbulent mHd Couette nanofluid flow and heat transfer using hybrid dTm-Fdm

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Particuology 2016年第3期14卷 95-101页

作者： S. mosayebidorcheh m. Sheikholeslami m. Hatami d.d. Ganji Young Researchers and Elite Club Najafabad Branch lslamicAzad University Ndjafabad Iran department of mechanical Engineering Lenjan Branch Islamic Azad University lsfahan Iron department of mechanical Engineering Babol University of Technology Babol Iran mechanical Engineering department Engineering and Technical College Esfarayen University Esfarayen North Khorasan lran

Unsteady turbulent magnetohydrodynamic nanofluid hydrothermal treatment is studied. The zero- equation turbulence model is used to simulate turbulent flow. The modeling results obtained by applying the hybrid differential transformation method-finite difference method to solve this problem confirm its viability. An analytical procedure is used for finding the effects of the problem parameters. Results indicate that the average Nusselt number over the lower plate depends linearly on volume fraction of nanofluid, Hall parameter, turbulent Eckert number, and Reynolds number whereas it is inversely proportional on the Hartmann number and the turbulent parameter.

关键词： Turbulent Hall effect Hybrid dTm-Fdm Nanofluid magnetohydrodynarnic couette flow

A fully-explicit discontinuous Galerkin hydrodynamic model for variably-saturated porous media

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Journal of Hydrodynamics 2014年第4期26卷 594-607页

作者： de mAET T. HANERT E. VANCLOOSTER m. Earth and Life Institute Environmental SciencesUniversité catholique de LouvainB-1348 Louvain-la-NeuveBelgium Georges Lema?tre Centre for Earth and Climate Research Université catholique de LouvainB-1348 Louvain-la-NeuveBelgium

Groundwater flows play a key role in the recharge of aquifers, the transport of solutes through subsurface systems or the control of surface runoff. Predicting these processes requires the use of groundwater models with their applicability directly linked to their accuracy and computational efficiency. In this paper, we present a new method to model water dynamics in variably- saturated porous media. Our model is based on a fully-explicit discontinuous-Galerkin formulation of the 3d Richards equation, which shows a perfect scaling on parallel architectures. We make use of an adapted jump penalty term for the discontinuous-Galerkin scheme and of a slope limiter algorithm to produce oscillation-free exactly conservative solutions. We show that such an approach is particularly well suited to infiltration fronts. The model results are in good agreement with the reference model Hydrus-ld and seem promising for large scale applications involving a coarse representation of saturated soil.

关键词： 3d subsurface flow model discontinuous Galerkin method slope limiters explicit time integration

management of patients with a short bowel

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World Journal of Gastroenterology 2001年第6期7卷 741-751页

作者： Jeremy m d Nightingale Consultant Gastroenterologist Gastroenterology CentreLeicester Royal InfirmaryUnited Kingdom

There are two common types of adult patient with a short bowel, those with jejunum in continuity with a functioning colon and those with a jejunostomy. Both groups have potential problems of undernutrition, but this is a greater problem in those without a colon, as they do not derive energy from anaerobic bacterial fermentation of carbohydrate to short chain fatty acids in the colon. Patients with a jejunostomy have major problems of dehydration, sodium and magnesium depletion all due to a large volume of stomal output. Both types of patient have lost at least 60 cm of terminal ileum and so will become deficient of vitamin B(12). Both groups have a high prevalence of gallstones (45%) resulting from periods of biliary stasis. Patients with a retained colon have a 25% chance of developing calcium oxalate renal stones and they may have problems with d(-) lactic acidosis. The survival of patients with a short bowel, even if they need long-term parenteral nutrition, is good.

关键词： Colon digestive System Humans Jejunostomy Nutrition disorders Risk Factors Short Bowel Syndrome

Low-temperature thermocatalytic particulate carbon decomposition via urea solution-combustion derived CeO2 nanostructures

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Journal of Rare Earths 2021年第1期39卷 67-74,I0003页

作者： S.P.Ratnayake m.m.m.G.P.G.mantilaka C.Sandaruwan d.dahanayake Y.Pivini Gunasekara S.Jeyasakthy N.m.Gurusinghe U.K.Wanninayake K.m.Nalin de Silva Sri Lanka Institute of Nanotechnology Nanotechnology and Science ParkHomagamaSri Lanka School of Science Royal Melbourne Institute of Technology University(RMIT)Victoria3000Australia Postgraduate Institute of Science University of PeradeniyaPeradeniyaSri Lanka Centre for Advanced materials and devices(CAmd) Department of ChemistryUniversity of ColomboColombo 00300Sri Lanka

A facile,one-pot,urea solution combustion route was utilized to synthesize highly catalytic CeO2 ***2 prepared under varying thermal conditions was characterized by electron microscopy,energy dispersive X-ray spectroscopy,X-ray diffraction,X-ray photoelectron spectroscopy,infrared and Raman *** the synthesis temperature is raised from 400 to 1000℃,the crystallite size and dspacing of nanoparticles are observed to reduce while cell parameters remain in the same *** size exhibits an accession from~20 to~50 nm along the *** CeO2 nanoparticles are detected as a composite structure of CeO2 and graphitic carbon nitride(g-C3 N4)produced by the pyrolysis of *** the solid carbon particulate oxidation capacity,an outstanding performance is exhibited by CeO2 synthesized at 800℃where the oxidation onset temperature is reduced by 27%compared with the *** superior performance is attributed to the carbon nitride-generated unique CeO2 nanomorphology consolidating ample reactive sites and facilitated oxygen delivery for a highly efficient thermocatalytic *** atmospheric pollution mitigation,synthesis of these CeO2 nanostructures represents a cost effective and convenient abatement technique for carbon particulates in comparison to cost-intensive,environmentally detrimental and noble-metal based techniques.

关键词： Ceria Nanoparticles Soot Solution combustion Graphitic carbon nitride Rare earths

Boundary conditions for porous solids saturated with viscous fluid

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Applied mathematics and mechanics(English Edition) 2009年第7期30卷 821-832页

作者： m.d.Sharma department of mathematics Kurukshetra University

Boundary conditions are derived to represent the continuity requirements at the boundaries of a porous solid saturated with viscous fluid. They are derived from the physically grounded principles with a mathematical check on the conservation of energy. The poroelastic solid is a dissipative one for the presence of viscosity in the interstitial fluid. The dissipative stresses due to the viscosity of pore-fluid are well represented in the boundary conditions. The unequal particle motions of two constituents of porous aggre~ gate at a boundary between two solids are explained in terms of the drainage of pore-fluid leading to imperfect bonding. A mathematical model is derived for the partial connec- tion of surface pores at the porous-porous interface. At this interface, the loose-contact slipping and partial pore opening/connection may dissipate a part of strain energy. A numerical example shows that, at the interface between water and oil-saturated sandstone, the modified boundary conditions do affect the energies of the waves refracting into the isotropic porous medium.

关键词： porous solid dissipative boundary conditions

Electrodeless plasma thrusters for spacecraft: a review

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Plasma Science and Technology 2017年第8期19卷 1-24页

作者： S N BATHGATE m m m BILEK d R mCKENZIE Applied and Plasma Physics School of PhysicsUniversity of Sydney

The physics of electrodeless electric thrusters that use directed plasma to propel spacecraft without employing electrodes subject to plasma erosion is reviewed. Electrodeless plasma thrusters are potentially more durable than presently deployed thrusters that use electrodes such as gridded ion,Hall thrusters, arcjets and resistojets. Like other plasma thrusters, electrodeless thrusters have the advantage of reduced fuel mass compared to chemical thrusters that produce the same thrust. The status of electrodeless plasma thrusters that could be used in communications satellites and in spacecraft for interplanetary missions is examined. Electrodeless thrusters under development or planned for deployment include devices that use a rotating magnetic field; devices that use a rotating electric field; pulsed inductive devices that exploit the Lorentz force on an induced current loop in a plasma; devices that use radiofrequency fields to heat plasmas and have magnetic nozzles to accelerate the hot plasma and other devices that exploit the Lorentz force. Using metrics of specific impulse and thrust efficiency, we find that the most promising designs are those that use Lorentz forces directly to expel plasma and those that use magnetic nozzles to accelerate plasma.

关键词： spacecraft a review propellant Lorentz thrust rotating radiofrequency erosion presently exploit

Luminescent polymer electrolytes based on chitosan and containing europium triflate

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Journal of Rare Earths 2016年第7期34卷 661-666页

作者： R.Alves A.S.S.de Camargo A.Pawlicka m.m.Silva Center of Chemistry University of MinhoGualtar4710-057 BragaPortugal Sao Carlos Institute of Physics University of Sao Paulo13566-590 Sao Carlos-SPBrazil Sao Carlos Institute of Chemistry University of Sao Paulo13566-590 Sao Carlos-SPBrazil

Solid polymer electrolytes based on chitosan and europium triflate were prepared by solvent casting and characterized by X-ray diffraction, scanning electron microscopy （SEm）, atomic force microscopy （AFm）, and photoluminescence spectroscopy. The X-ray diffraction exhibited that the samples were essentially amorphous with organized regions over the whole range of the salt content studied. The AFm analysis demonstrated that the smoother sample had roughness of 4.39 nm. Surface visualization through SEm revealed good homogeneity without any phase separation for more conductive samples and the less conductive showed some im- perfections on the surface. The emission and excitation spectra displayed the characteristic bands of Eu（CF3SO3）3 in addition to broad bands corresponding to the polymer host. The excited state 5d0 lifetime values ranged from 0.29-0.37 ms for the studied samples.

关键词： solid polymer electrolytes natural polymers photoluminescence spectroscopy rare earths

ON THE EXISTENCE OF ZERO POINTS OF A CONTINUOUS FUNCTION

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Acta mathematica Scientia 2002年第2期22卷 171-177页

作者： J.m. Sorianodepartamento de Andlisis matematico, Facultad de matemdticas, Universidad de Sevilla, Aptdo. 1160, Sevilla 41080, Spain departamento de Análisis matemático Facultad de Matemáticas Universidad de Sevilla Aptdo. 1160 Sevilla 41080 Spain

A sufficient condition is given to assert that a continuous mapping between Rm and Rn has a zero. The constructive proof of the result is based upon continuation methods and supplies the existence of a path leading to... 详细信息

关键词： Zero point continuation methods Banach fixed point theorem homotopy topological direct sum isomorphism k-contractive mapping