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3D CFD MODELING OF WATER AND SEDIMENT FLOW IN A HYDROPOWER RESERVOIR

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International Journal of Sediment Research 1999年第1期 20-28页

作者： nils reidar b.olsen 1, Oscar F.JIMENEZ 2, Lars AbRAHAMSEN 3, and Aslak L*IVOLL 4

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关键词： Computational fluid dynamics Sediment transport Hydropower Reservoirs Model verification

Simulation for MSS-2 low-perigee elliptical orbit satellites:an example of lithospheric magnetic field modelling

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Earth and Planetary Physics 2023年第1期7卷 151-160页

作者： Yi Jiang nils olsen JiaMing Ou Qing Yan State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyTaipa 999078MacaoChina Division of Geomagnetism DTU SpaceNational Space InstituteTechnical University of DenmarkDiplomvej 3712800 Kgs.LyngbyDenmark

A future constellation of at least four geomagnetic satellites(designated Macao Scientific Satellite-1(MSS-1)and Macao Scientific Satellite-2(MSS-2))was recently proposed,to continue high-quality geomagnetic observations in the post-Swarm period,focusing especially on collecting data that will provide a global,three-dimensional survey of the geomagnetic *** this paper,we present a simulation of two years of orbits(2020.01.01-2022.01.01)of two satellites(tentatively denoted as MSS-2)that are constellated in elliptical(200×5,300 km)low-perigee *** comparing error variances of Gauss coefficients,we investigate the sensitivity of lithospheric magnetic field modelling to data collected from various satellite orbits,including a near circular reference orbit of 300×350km,and elliptical orbit of 180×5,300 km,220×5,300 km,200×3,000 km and 200×1,500 *** find that in two years the two MSS-2 satellites can collect 35,000 observations at altitude below 250 km,data that will be useful in advancing the quality of lithospheric magnetic field modelling;this number of observations reflects the fact that only 4.5%of the flight time of these satellites will be below250 km(just 6.4%of their flight time below 300 km).by combining observations from the MSS-2 satellites’elliptical orbits of 200×5,300km with observations from a circular reference orbit,the variance of the geomagnetic model can be reduced by a factor of 285 at spherical harmonic degree n=200 and by a factor of 1,300 at n=*** planned lower perigee of their orbits allows the new satellites to collect data at unprecedentedly lower altitudes,thus dramatically improving the spatial resolution of satellite-derived lithospheric field models,(up to 80%at n=150).In addition,lowering the apogee increases the time interval during which the satellites fly at near-Earth altitudes,thus improving the model predictions at all spherical harmonic degrees(around 52%-62%at n=150).The upper limit of the expected improvement to t

关键词： elliptical orbit satellite orbit simulation lithosphere field modelling spherical harmonics

Energy Dissipation Within the Wave Run-Up at Stepped Revetments

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Journal of Ocean University of China 2017年第4期16卷 649-654页

作者： KERPEN nils b bUNG Daniel b VALERO Darnel SCHLURMANN Torsten Ludwig-Franzius-lnstitute Leibniz Universitat Hannover30167 HannoverGermany Hydraulic Engineering Section Fachhochschule Aachen52066 AachenGermany

To understand the processes and energy dissipation performance caused by turbulence during the wave run-up over a stepped revetment,hydraulic model tests with steady flow conditions are conducted and correlated with unsteady flow conditions of the wave run-up within a short time *** irregular waves,the run-up reduction over a stepped revetment is dependent on the Iribarren number and decreases for decreasing Iribarren *** gradients are found to be similar in a steady and unsteady flow regime near the pseudo-bottom.

关键词： run-up stepped revetment roughness: energy dissipation

Initial scalar lithospheric magnetic anomaly map of China and surrounding regions derived from CSES satellite data

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Science China(Technological Sciences) 2021年第5期64卷 1118-1126页

作者： WANG Jie SHEN XuHui YANG YanYan ZEREN ZhiMa HULOT Gauthier olsen nils ZHOU bin MAGNES Werner DE SANTIS Angelo HUANG JianPing GUO Feng LIU WenLong YU Jingbo National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China School of Space and Environment Beihang UniversityBeijing 100191China Universitéde Paris Institut de physique du globe de ParisCNRSParis F-75005France DTU Space National Space InstituteTechnical University of DenmarkKongens Lyngby 2800Denmark National Space Science Center Chinese Academy of SciencesBeijing 100190China Space Research Institute Austrian Academy of SciencesGraz 8042Austria Istituto Nazionale di Geofisica e Vulcanologia Via di Vigna MurataRome 605Italy School of Earth Sciences Hebei GEO UniversityShijiazhuang 050031China

The China Seismo-Electromagnetic Satellite(CSES),China’s first satellite to measure geophysical fields with scientific goals in both space and solid earth physics,was launched successfully in February *** carries high-precision magnetometers to measure the geomagnetic *** this study,the CSES magnetic data were used to extract the signal of the lithospheric magnetic field caused by magnetized rocks in the crust and uppermost ***,an along-track analysis of the CSES magnetic data was undertaken near the bangui magnetic anomaly in central Africa and the Tarim magnetic anomaly in China,demonstrating that the CSES magnetic data are indeed sensitive to the lithospheric magnetic anomaly *** a lithospheric magnetic anomaly map over China and surrounding regions was *** map is consistent with the lithospheric part of the CHAOS-7 *** particular,it clearly reveals four major magnetic anomalies containing long-wavelength signals at the altitude of lowearth-orbiting *** magnetic highs are located over the Tarim,Sichuan and Songliao basin,the origins of which could be related to large-scale tectonic-magmatic activities during geological history.A prominent magnetic low is otherwise found in the southern Himalayan-Tibetan plateau,possibly caused by the shallow Curie depth in this *** further improve the precision of the lithospheric magnetic field model,more detailed data processing and multi-source data merging are needed.

关键词： anomaly lithospheric Himalayan

Correlation between the results of three physical fitness tests(endurance,strength,speed) and the output measured during a bicycle ergometer test in a cohort of military servicemen

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Journal of Medical Colleges of PLA(China) 2016年第3期31卷 134-139页

作者： Stefan Sammito nils Gundlach Irina b?ckelmann bundeswehr Medical Service Headquarters Section Health PromotionSports and Nutrition Medicine Otto von Guericke University Magdeburg Medical FacultyDepartment of Occupational Medicine bundeswehr Medical Clinic Rotenburg

background: Physical fitness tests are widely used to assess endurance,sprint ability,coordination and/or *** objective of the present study was to analyze the degree to which the results of the bundeswehr basis Fitness Test(bFT)–a physical fitness test comprising a sprint test(11×10-m shuttle test),a flexed-arm hang test and a 1000-m run–are consistent with the output measured during a bicycle ergometer *** number of false-positive and falsenegative results with regard to the assessment of physical fitness were also ***: As part of a retrospective study,health assessments from 323 reenlistment examinations were evaluated regarding the output measured during a bicycle ergometer test and compared with the bFT results of the ***: Overall,a good correlation was shown between the bicycle ergometer test results and the results achieved in the bFT *** three disciplines of the bFT showed a highly significant correlation with the relative output achieved during the bicycle ergometer test(PbFT score was highly significantly correlated(PbFT results measured in the three physical fitness test items were highly correlated with the output measured during the bicycle ergometer *** rate of false-positive and false-negative results was *** test items thus represent an appropriate measurement instrument because the test items require few equipment and less ***,a large number of subjects can be *** suggest that it would be more useful to assess the physical fitness of this special group exclusively on the basis of the bFT instead of using the bicycle ergometer test.

关键词： Physical fitness Military Ergometer test bicycle Treadmill

3D X-ray microscopy with a CsPbbr3 nanowire scintillator

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Nano Research 2023年第1期16卷 1084-1089页

作者： Hanna Dierks Zhaojun Zhang nils Lamers Jesper Wallentin Lund University Synchrotron Radiation Research and NanoLundBox 118SE-22100 LundSweden

X-ray microscopy is an essential imaging method in many scientific fields,which can be extended to three-dimensional(3D)using ***,metal halide perovskite(MHP)nanomaterials have become a promising candidate for X-ray scintillators,due to their high light yield,high spatial resolution,and easy *** requires many projections and therefore scintillators with excellent *** is challenging for MHPs,which often suffer from fast degradation under X-ray irradiation and ambient ***,we demonstrate that MHP scintillators of CsPbbr3 nanowires(diameter:60 nm,length:5–9μm)grown in anodized aluminum oxide(CsPbbr3 NW/AAO)have sufficient stability for X-ray micro-tomography.A tomogram was taken with a Cu X-ray source over 41 h(dose 4.2 Gyair).During this period the scintillator brightness fluctuated less than 5%,which enabled a successful reconstruction.A long-term study with 2 weeks of continuous X-ray exposure(37.5 Gyair)showed less than 14%fluctuations in brightness and no long-term degradation,despite variations in the ambient relative humidity from 7.4%RH to 34.2%*** resolution was stable at(180±20)lp·mm−1,i.e.,about 2.8 *** demonstrates that CsPbbr3 NW/AAO scintillators are promising candidates for high resolution X-ray imaging detectors.

关键词： tomography perovskites scintillators X-ray imaging micrometer spatial resolution

Two become one:combination of two risk factors in a new glaucoma animal model

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Neural Regeneration Research 2024年第5期19卷 982-983页

作者： nils Kluge Sabrina Reinehr Experimental Eye Research Institute University Eye HospitalRuhr-University BochumBochumGermany

Glaucoma is a group of eye diseases characterized by progressive loss of retinal ganglion cells(RGCs)and optic nerve *** this process,the visual field is reduced,and blindness may ultimately ***,glaucoma is the second leading cause of blindness,with about 80 million people *** is a multifactorial disease and due to its complexity,the exact pathomechanisms are not fully understood ***,different risk factors,such as elevated intraocular pressure(IOP),age,or myopia,have been identified to date(EGS,2021).

关键词： elevated exact glaucoma

DETERMINISTIC HOMOGENIZATION OF QUASILINEAR DAMPED HYPERbOLIC EQUATIONS

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Acta Mathematica Scientia 2011年第5期31卷 1823-1850页

作者： Gabriel Nguetseng Hubert Nnang nils Svanstedt Faculty of Sciences University of Yaounde I P.O. Box 812 Yaounde Cameroon Ecole Normale Suprieure University of Yaounde I P.O. Box 47 Yaounde Cameroon Department of Mathematical Sciences University of Gothenburg SE-412 96 Gteborg Sweden

Deterministic homogenization is studied for quasilinear monotone hyperbolic problems with a linear damping term. It is shown by the sigma-convergence method that the sequence of solutions to a class of multi-scale hig... 详细信息

关键词： homogenization sigma-convergence quasilinear hyperbolic

Facing different predators： adaptiveness of behavioral and morphological traits under predation

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Current Zoology 2017年第3期63卷 249-257页

作者： Martina HEYNEN nils bUNNEFELD Jost bORCHERDING Department of General Ecology and Limnology Ecological Field Station Grietherbusch Zoological Institute of the University of Cologne Rees Germany Department of Chemistry Umea University Umea Sweden Department of Ecology and Environmental Sciences Umea University Umea Sweden Department of Life Sciences Biological and Environmental Sciences School of Natural Sciences University of Stirling Stirling UK

Predation is thought to be one of the main structuring forces in animal communities. However, se- lective predation is often measured on isolated traits in response to a single predatory species, but only rarely are selective forces on several traits quantified or even compared between different predators naturally occurring in the same system. In the present study, we therefore measured be- havioral and morphological traits in young-of-the-year Eurasian perch Perca fluviatilis and com- pared their selective values in response to the 2 most common predators, adult perch and pike Esox lucius. Using mixed effects models and model averaging to analyze our data, we quantified and compared the selectivity of the 2 predators on the different morphological and behavioral traits. We found that selection on the behavioral traits was higher than on morphological traits and perch predators preyed overall more selectively than pike predators. Pike tended to positively se- lect shallow bodied and nonvigilant individuals （i.e. individuals not performing predator inspec- tion）. In contrast, perch predators selected mainly for bolder juvenile perch （i.e. individuals spend- ing more time in the open, more active）, which was most important. Our results are to the best of our knowledge the first that analyzed behavioral and morphological adaptations of juvenile perch facing 2 different predation strategies. We found that relative specific predation intensity for the di- vergent traits differed between the predators, providing some additional ideas why juvenile perch display such a high degree of phenotypic plasticity.

关键词： behavior morphological variation Perca f/uviatilis perch pike predator-specific defenses selective predation