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Insect Science 2011年第5期18卷 533-540页

作者： Viviana loaiza Jayne l. Jonas Anthony Joern Division of Biology Kansas State University Manhattan Kansas USA

Key elements such as nitrogen （n） and phosphorus （P） are often limiting relative to the nutritional needs of herbivores that feed on them. While n often limits insect herbivores in natural terrestrial ecosystems, the effect of P is poorly studied in the field, even though compelling hypotheses from the ecological stoichiometry literature predict its importance. We evaluated small-scale spatial distributions of, and herbivory by, grasshoppers among neighboring plots that vary in foliar-n and -P in tallgrass prairie. Grasshopper densities were 67% greater in n-fertilized plots but detected no effect to grasshopper densities from P-fertilizer. leaf damage to the dominant grass Andropogon gerardii was 32% greater in n-fertilized plots, but no response to foliar-P was detected. Herbivore damage to a common forb, goldenrod （Solidago missouriensis）, was not strongly linked by fertilizer treatments, although there was increased leaf damage in n-fertilizer treatments when no P was applied （a significant n ~ P interaction）. Under field conditions at local scales, we conclude that spatially heterogeneous distributions of grasshoppers are primarily affected by foliar-n in host plants with little evidence that P-levels contribute to the spatial patterns.

关键词： Andropogon gerardii ecological stoichiometry insect herbivory Konza Prairie n-P fertilization experiment Solidago rnissouriensis

Potential influence of wildfire in modulating climate-induced forest redistribution in a central Rocky Mountain landscape

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Ecological Processes 2017年第1期6卷 52-68页

作者： John l.Campbell Douglas J.Shinneman Department of Forest Ecosystems and Society Oregon State UniversityCorvallisORUSA U.S.Geological Survey Forest and Rangeland Ecosystem Science CenterBoiseIDUSA.

Introduction:Climate change is expected to impose significant tension on the geographic distribution of tree ***,tree species range shifts may be delayed by their long life spans,capacity to withstand long periods of physiological stress,and dispersal *** could theoretically break this biological inertia by killing forest canopies and facilitating species redistribution under changing *** investigated the capacity of wildfire to modulate climate-induced tree redistribution across a montane landscape in the central Rocky Mountains under three climate scenarios(contemporary and two warmer future climates)and three wildfire scenarios(representing historical,suppressed,and future fire regimes).Methods:Distributions of four common tree species were projected over 90 years by pairing a climate niche model with a forest landscape simulation model that simulates species dispersal,establishment,and mortality under alternative disturbance regimes and climate ***:Three species(Douglas-fir,lodgepole pine,subalpine fir)declined in abundance over time,due to climate-driven contraction in area suitable for establishment,while one species(ponderosa pine)was unable to exploit climate-driven expansion of area suitable for *** fire frequency accelerated declines in area occupied by Douglas-fir,lodgepole pine,and subalpine fir,and it maintained local abundance but not range expansion of ponderosa ***:Wildfire may play a larger role in eliminating these conifer species along trailing edges of their distributions than facilitating establishment along leading edges,in part due to dispersal limitations and interspecific competition,and future populations may increasingly depend on persistence in locations unfavorable for their establishment.

关键词： Forest disturbance Wildfire Climate change Central Rocky Mountains Climate niche Species migration Species distribution

Global evolution of Equidae and Gomphotheriidae from South America

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Integrative Zoology 2014年第4期9卷 434-443页

作者： Josél.PRADO María T.AlBERDI InCUAPA CONICET-UNICENNational University of Central Buenos Aires ProvinceOlavarríaArgentina Department of Paleobiology Museo Nacional de Ciencias NaturalesCSICMadridSpain

The contemporary South American mammalian communities were determined by the emergence of the Isthmus of Panama and by the profound climatic oscillations during the *** and gomphotheres were 2 very conspicuous groups of immigrant mammals from north America that arrived in South America during the *** present study compiles updated data on the phylogeny,systematics and ecology of both groups in South *** horses in South America are represented by 2 genera,Hippidion and Equus,as are the gomphotheres,represented by Cuvieronius and *** genera of horses include small(Hippidion devillei,***,*** and ***)and large forms(Equus neogeus and ***),which dispersed into South America using 2 different *** possible model for this dispersion indicates that the small forms used the Andes corridor,while larger horses dispersed through the eastern route and through some coastal *** the case of gomphotheres,Cuvieronius and Stegomastodon reached South America in 2 independent dispersal events,and Cuvieronius dispersed across the Andean corridor,while large Stegomastodon spread along the eastern *** and gomphotheres present values ofδ^(13)C from woodlands to C4 grass*** present lower values ofδ^(13)C than Equus in the late Pleistocene,whereas the gomphotheres diverge from value ofδ^(18)O,reflecting that Cuvieronius inhabited the Andean corridor and Stegomastodon dispersed through eastern *** gomphothere and horse species recorded in South America became extinct around the time that humans arrived.

关键词： Equidae Gomphotheriidae Plio-Pleistocene South America

MICROSTRUCTURAl EVOlUTIOn OF AS-CAST ZA27 AllOY DURInG COMPRESSIVE CREEP

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Acta Metallurgica Sinica(English letters) 2003年第5期16卷 335-341页

作者： X.W.Wei B.l.Shen DepartmentofMaterialsScienceandEngineering SichuanInstituteofTechnologyChengdu610039China DepartmentofMetalScience SichuanUniversityChengdu610065China

Phase transformation and micro structural change of an as-cast ZA27 alloy were investigated during compressive creep by X-ray diffraction technique, SEM and TEM. Compressive creep induced decomposition of α metastable η' phase and a four-phase transformation, α + ε → T' + η and T' → θ, occurred during the compressive creep testing. The occurrence of negative creep in the alloy resulted from the volume expansion caused by the four-phase transformation. A micro structural change was also observed from a lamellar structure into a spheroidized structure in higher creep strain of tested specimens. It provided evidence of compressive creep induced phase transformation which occurred in ageing process.

关键词： microstructure change compressive creep ZA27 alloy

Practical problems in regulatory toxicology Ⅱ:Control of contamination

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中国药理学与毒理学杂志 2013年第3期 513-514页

作者： Janet l KEllY CJS Scientific ltd HarrogateUKHG3 5BJ.

Although highly regulated,all non-clinical toxicology studies have the potential to experience practical *** of potential hurdles and planning for success are key actions for all investigators to ensure a study is robust and suitable for submission and regulatory *** presentation will examine the whole study conduct process and illustrate steps you can take to the potential contamination of control samples and,in the event of an unexpected result being obtained,the procedures that must be carried out to investigate the *** authorities across the globe have focused on the contamination of control biological samples as a serious risk to compound development.A number of studies have been rejected by regulatory authorities in recent years due to the occurrence of test material in control samples and various legislationhas been introduced on the *** it was common place to only demonstrate the presence of test material at one or two time points in treated animals during a study and either not take or not analyse control *** today almost every study has a complete time profile of blood levels in all animals and analytical techniques have become ever more ***,the potential to identify test material in control samples is *** is a very costly problem for all involved in regulatory toxicology as it leads to additional time investigating the source of the problem,possible extra costs in repeating studies and the consequent use of more animals and potentially delays in registration and even loss of market *** which can be taken to limit its occurrence and a process of investigation of any positive results will be *** presentation will illustrate the need for scientists from all departments involved in a regulatory study to contribute to the successful *** regards to GlP compliance,the involvement and leadership of the Study Director in determ

关键词： Control of contamination Practical problems in regulatory toxicology

Dynamic analysis of a flameless combustion model combustor

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Science China(Technological Sciences) 2010年第8期53卷 2291-2298页

作者： CUI YuFeng lüXuan XU Gang nIE ChaoQun Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China Graduate School of the Chinese Academy of Sciences Beijing 100190China

Flameless combustion is a new technology with the following advantages:1)Ultra-low emissions of both nOX and CO;2)fuel flexibility,from liquid fuels,natural gas to hydrogen-rich syngas;3)lower possibility of flashback and thermoacoustic *** this paper,we focus on the dynamic characteristics of a flameless model *** results show that flameless combustion can lower emissions while maintaining combustion ***,combining a pilot flame with flameless combustion may excite thermoacoustic instability.

关键词： flameless combustion thermoacoustic oscillations dynamic pressure characteristics gas turbine

The dynamics of a nanosecond gas discharge development with an extended slot cathode in argon

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Plasma Science and Technology 2020年第12期22卷 78-88页

作者： n A ASHURBEKOV K O IMInOV G S SHAKHSInOV M Z ZAKARYAEVA K M RABADAnOV Dagestan State University Faculty of PhysicsMakhachkala 367000Russia Institute of Physics DFRC of RASMakhachkala 367015Russia

The article presents the results of an experimental study and numerical modelling for the formation and development dynamics of a high-voltage transverse nanosecond discharge generated by a slot cathode in an argon medium at a pressure range of 1–10 Torr. numerical modelling was carried out under similar experimental conditions for the processes of formation and propagation of ionisation waves, electron density distribution, excited atom and average electron energy in the discharge gap, including the cavity inside the cathode. At a pressure of p=1 Torr, a classical version of a high-voltage discharge is demonstrated to take place with no penetration of the plasma into the cathode cavity and no observed hollow cathode effect. An increase in gas pressure to 5 Torr leads to a penetration of plasma into the cathode cavity with the formation of a cathodic potential drop(CPD) region. Electrons emitted from the side surfaces of the cavity pass through the CPD region without collisions, oscillate inside the cathode cavity;the hollow cathode effect is fully manifested. At р=10 Torr, the modelling results qualitatively coincide with the results at р=5 Torr;in this case, however, hardly any accelerated electrons are observed in the gap between the electrodes, due to their energetic relaxation both inside the cathode cavity and when exiting from it. In both cases, the plasma structure formed at the exit of the cathode cavity involves a concentration of charged particles an order of magnitude higher than that in the rest of the gap, leading to a self-limiting discharge current effect. The results of the numerical modelling are in good agreement with experimental data.

关键词： nanosecond gas discharge numerical simulation argon excited atoms

Calculation of stratosphere–troposphere exchange in East Asia cut-off lows:cases from the lagrangian perspective

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Atmospheric and Oceanic Science letters 2016年第1期9卷 31-37页

作者： WU Xue lü Da-Ren Key laboratory for Atmosphere and Global environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

In this study,the authors focus on the cut-off low pressure systems（COls）lingering over East Asia in late spring and early summer and quantify the two-way stratosphere–troposphere exchange（STE）by 3D trajectory integrations,achieved using a revised version of the UK Universities Global Atmospheric Modelling Programme Offline Trajectory Code（Version 3）.By selecting 10 typical COls and calculating the cross-tropopause air mass fluxes,it is found that stratosphere-to-troposphere transport（STT）fluxes exist in the center of COls;and in the periphery of the COl center,troposphereto-stratosphere transport（TST）fluxes and STT fluxes are distributed *** transport fluxes in COls are from stratosphere to troposphere,and the magnitude is about 10-4 kg m-2 *** ratio between the area-averaged STT and TST fluxes increases with increasing strength of the *** adopting appropriate residence time,the spurious transports are effectively ***,the authors compare the results with previous studies,and find that the cross-tropopause fluxes（CTFs）induced by COls are about one to two orders of magnitude larger than global *** play a significant role in local,rapid air mass exchanges,although they may only be responsible for a fraction of the total STE.

关键词： stratosphere–troposphere exchange cut-off low trajectory model

Intercomparison of three South China Sea circulation models

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Acta Oceanologica Sinica 2004年第1期23卷 41-50页

作者： DUYan WAnGDongxiao ZHOUWeidong WAnGWeiqiang l1UXiongbin KeylaboratoryofTropicalMarineEnvironmentalDynamics SouthChinaSeaInstituteofOceanologyChineseAcademyofSciencesGuangzhou510301China

Three numerical oceanic circulation models: POM(Princeton ocean model), MICOM(Miami isopycnal coordinates ocean model) and GFDl model, which adopt sigma coordinate, isopycnal coordinate and depth coordinate respectively, are used in the South China Sea(SCS) circulation modeling. Model domain has the same topography, grid resolution, initial conditions and surface boundary conditions. The maximum ocean depth is set as 1 000 m. Grid resolution is 0.5o×*** conditions are supplied by climatological temperature and salinity data in January. Climatological wind stress, surface temperature and salinity are used as surface forcing. lateral boundaries take enclosed boundary conditions artificially. Focusing on the common point of different ocean circulation models, the circulation pattern in winter and summer, sea surface height in the northern SCS, seasonal cycle of the mixed layer thickness in the southern SCS, barotropic stream function in winter are selected to carry out intercomparison. In winter, a strong cyclonic gyre occupies the whole SCS. In summer, a strong anticyclonic gyre occupies the southern SCS and a weak cyclonic gyre occupies the northern SCS. The thickness of the mixed layer shows bimodal features in the southern SCS. Sea surface height anomaly(SSHA) in the northern SCS has an eastward propagating feature, in agreement with the remote sensing observation. Barotropic stream functions indicate that the circulation of the upper ocean is mainly forced by inputting of wind stress curl under closed boundary conditions. In addition, three models also show distinct differences. The basin-scale circulation from MICOM is distinct. Output of POM has more mesoscale eddies than others. GFDl model seems good at simulating westward intensification.

关键词： models intercomparison South China Sea ocean circulation model

High-Order Discontinuous Galerkin Method for Hovering Rotor Simulations Based on a Rotating Reference Frame

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Transactions of nanjing University of Aeronautics and Astronautics 2019年第1期36卷 57-70页

作者： ZHAnG Tao lü Hongqiang QIn Wanglong CHEn Zhengwu Department of Aerodynamics Nanjing University of Aeronautics and Astronautics China Aerodynamics Research and Development Center

An implicit higher ? order discontinuous Galerkin(DG) spatial discretization for the compressible Euler equations in a rotating frame of reference is presented and applied to a rotor in hover using hexahedral grids. Instead of auxiliary methods like grid adaptation,higher ? order simulations(fourth ? and fifth ? order accuracy) are *** numerical experiments are carefully designed,conducted and analyzed. The results show generally excellent consistence with references and vigorously demonstrate the higher?order DG method's better performance in loading distribution computations and tip vortex capturing, with much fewer degrees of freedom(DoF). Detailed investigations on the outer boundary conditions for hovering rotors are presented as well. A simple but effective speed smooth procedure is developed specially for the DG method. Further results reveal that the rarely used pressure restriction for outlet speed has a considerable advantage over the extensively adopted vertical speed restriction.

关键词： high-order method(HOM) discontinuous Glaerkin method(DGM) Euler equation hovering rotor simulation tip vortex