检索结果-南通市图书馆

YANGTZE DISCHARGE MEMORY

在线全文

学校读者我要写书评

暂无评论

第四纪研究 2009年第4期29卷 696-700页

作者： klaus Fraedrich Xiuhua Zhu KlimaCampus Meteorologisebes Institut and Max Planck lnstitut D-20146 Hamburg Germany

We present a review on studies focusing on memories in hydrological time series in the Yangtze Basin basedon observational and reconstructed historical data. Memory appears as scaling of power spectra, S(f) ～f^(-β) ,with 0 <β≤ *** presence of scaling is noteworthy in daily river discharge time series.. 1 ) from weeks to a couple of years, power spectrafollow flicker noise, that is β≈ 1 ; 2) beyond years, spectral scaling approaches β≈ 0.3. In historical time series of floods anddroughts,power spectra also shows scaling with β≈ 0.38 ～ 0.52. Furthermore, a 70-year peak is detected in historicalmaritime events series,which also appears in other past climate indicators. Presence of memory in these hydrological timeseries implies clustering of extremes and scaling of their recurrence times, therefore, probabilistic forecast potential forextremes can be derived. On the other hand,although several physical processes, for example,soil moisture storage and highintermittency of precipitation,have been suggested to be the possible candidates contributing to the presence of long termmemory, they remain open for future research.

关键词：长江流域水灾降雨量旱灾

Tree survival and maximum density of planted forests–Observations from South African spacing studies

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2015年第1期2卷 11-19页

作者： klaus v.Gadow Heyns Kotze Department of Forest and Wood Science University of Stellenbosch University of G?ttingen Mondi South Africa Division Hilton South Africa

Background：Among the most important aspects of risk and hazard studies relating to forest ecosystems are maximum forest density and density-dependent tree ***：Long-term observations about the maximum density of unthinned Pinus patula and *** field plots based on the Correlated Curve Trend（CCT）spacing studies which were established almost 8 decades ago by O’Connor（Forest Research with Special Reference to Planting Distances and Thinning,1935）in South *** specific approaches were introduced for analysing maximum density and tree survival,namely the‘limiting line’,Nilson’s sparsity and tree survival with the Weibull ***：The main results are：a）Maximum densities differ greatly among the two species grown on the same site and within the same species grown on different sites;it is possible to relate these differences to site index in both species.b）The relationship between the quadratic mean diameter and the minimum average spacing of surviving trees（known as Nilson’s Sparsity）appears to be surprisingly similar in both species.c）An analysis of tree survival in response to different initial planting espacements shows that the Weibull survival function parameters can be estimated if the initial planting density is *** result is presented for each of the eight large experiments used in this ***：This study contributes to a better understanding of tree survival and maximum density which are the key factors required for estimating risk and *** risk of tree mortality is not constant,but varies with tree species,planting density,tree age and growing *** estimating that risk,therefore,continuous long-term observation on different sites and with varying planting densities,as provided by the unthinned CCT series,are essential.

关键词： Self-thinning Mortality CCT Pinus patula Pinus elliottii South Africa Nelder

Non-Metallic Inclusions in HSLA Steel-Origin,Detection and Refractory Systems to Improve Cleanness

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第S1期18卷 521-529页

作者： Dettela Heiko Klenner Gerald Cappel Juergen Wuennenberg klaus RHI-AG 115007 LianoingBayuquanPR China RHI-AG 1100 ViennaAustria Cappel Stahl Consulting 40667 MeerbuschGermany Steel Consulting 47249 DuisburgGermany

HSLA steels need extremely low levels of tramp elements like P,S,H and O *** tapping the steel is deoxidized with aluminum and in the secondary metallurgy sulphur ( 50 μm are harmful for the *** large inclusions are seldom and difficult to be *** inclusions of < 15 μm do no harm to the *** origin of non-metallic inclusions is,roughly spoken,one third each of de-oxidation-/reoxidation products,refractory and casting *** carry-over is mainly avoided by sensitive electronic *** covers and shrouding systems of the steel stream during the transfer of metal between ladle,tundish and mold are effective to avoid *** to control the flow of steel in tundish and mold favor the floatation of inclusions and their even distribution in the strand.

关键词： extra low contents of P,S and H Extraction metallurgy Ca-treatment control of slag carry-over shrouding flow control separation of inclusions inspection systems

Telling Duckweed Apart:Genotyping Technologies for the Lemnaceae

在线全文

学校读者我要写书评

暂无评论

应用与环境生物学报 2013年第1期19卷 1-10页

作者： klaus J.Appenroth Nikolai Borisjuk Eric Lam University of Jena Institute of General Botany and Plant Physiology Plant Biology and Pathology Rutgers State University of New Brunswick

The family of Lemnaceae,commonly called duckweed,comprise five genera and 37 species of aquaticmonocotyledonous plants that are endemic to lakes,ponds and brackish water bodies on most continents. They are angiospermsthat have the highest biomass production rate and have been used to remediate wastewater from both municipal andindustrial sources. With these attractive features,duckweed is poised to be a novel agricultural platform that can complementcurrent terrestrial crops. In addition,their remarkable ability to adapt to diverse climates and conditions may provide newunderstanding of stress tolerance and genome adaptability mechanisms. However,one of the first challenges facing theseapplications is to establish reliable and rapid methods for identification of closely related strains that may have very differentbehaviour or properties. This review article summarizes the state of the arts for this endeavour and provides the outlook for thisquest in the near future.

关键词： RAPD ISSR AFLP 环境生物学

Spatio-temporal characteristics of cultivated land fragmentation in different landform areas with a case study in Northeast China

在线全文

学校读者我要写书评

暂无评论

Ecosystem Health and Sustainability 2020年第1期6卷 581-591,580页

作者： Fengkui Qian Yanru Chi Rattan Lal klaus Lorenz College of Land and Environment Shenyang Agriculture UniversityShenyangPR China National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources ShenyangPR China Carbon Management and Sequestration Center School of Environment and Natural ResourcesThe Ohio State UniversityColumbusOHUSA

Assessing the temporal and spatial characteristics of cultivated land fragmentation is necessary to identify management practices that can reduce negative environmental ***,the purpose of this study was to use principal component analysis and spatial autocorrelation to analyze the dynamic characteristics of cultivated land fragmentation in different landform areas in Liaoning Province,China,in terms of time and *** additional objective was to match the changes with the natural and social environment to support the sustainable development of fragmented cultivated *** results indicated that the evolutionary trends of cultivated land fragmentation in the central plain area showed a weakening trend,contrary to those observed in the western hilly and eastern mountainous ***,the spatial distribution characteristics of cultivated land fragmentation in the western hilly area were generally“external low,internal high,”primarily because of the edge density of cultivated land *** spatial distribution characteristics of cultivated land fragmentation in the central plain area were generally“external high,internal low,”primarily because of the number and division of cultivated land *** spatial distribution characteristics of cultivated land fragmentation in the eastern mountainous area were generally“south low,north high”because of the division of cultivated land *** results can provide guidelines for planners,managers,decision-makers and others to formulate regulatory policies,identify land remediation areas,and promote the sustainable development of cultivated land.

关键词： Cultivated land fragmentation spatiotemporal characteristics different landforms Northeast China

Acoustic waveform inversion in frequency domain:Application to a tunnel environment

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2021年第5期6卷 560-576页

作者： Christopher Riedel Khayal Musayev Matthias Baitsch Hehua Zhu klaus Hackl Institute of Mechanics of Materials Ruhr-Universitat BochumBochumGermany Bochum University of Applied Sciences BochumGermany Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghaiChina

Waveform inversion is an approach used to find an optimal model for the velocity field of a ground structure such that the dynamic response is close enough to the given seismic ***,a suitable numerical approach is employed to establish a realistic forward computer *** forward problem is solved in the frequency domain using higher-order finite *** velocity field is inverted over a specific number of discrete frequencies,thereby reducing the computational cost of the forward calculation and the nonlinearity of the inverse *** results are presented for different frequency sets and with different source and receiver locations for a twodimensional *** influence of attenuation effects is also *** results of two blind tests are presented where only the seismic records of an unknown synthetic model with an inhomogeneous material parameter distribution are provided to mimic a more realistic ***,the result of the inversion in a three-dimensional space is illustrated.

关键词： Wave propagation Acoustics Perfectly matched layers Full waveform inversion Seismic imaging Tunneling Absorbing boundaries

Belowground Tritrophic Food Chain Modulates Soil Respiration in Grasslands

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2018年第1期28卷 114-123页

作者： Andrey S.ZAITSEV klaus BIRKHOFER Klemens EKSCHMITT Volkmar WOLTERS Institute of Animal Ecology Justus-Liebig-University of Giessen Department of Ecology Brandenburg University of Technology Cottbus-Senftenberg

Edaphic biota significantly affects several essential ecological functions such as C-storage, nutrient turnover, and ***, it is not completely understood how belowground animal contribution to these functions changes in grasslands subject to different land use types. A microcosm experiment was carried out to test the effect of a tritrophic food chain on CO_2 release from grassland soils. Soil was collected from three differently managed grassland systems(meadow, pasture, and mown pasture) located in three distinct German regions that cover a north-south gradient of approximately 500 km. The tritrophic food chain comprised natural edaphic microflora, nematodes, and predatory gamasid mites. The experimental design involved a full factorial combination of the presence and absence of nematodes and gamasid mites. Nematodes significantly increased the CO_2 emissions in most treatments,but the extent of this effect varied with land use type. The fact that grazing by nematodes stimulated the metabolic activity of the edaphic microflora over a wide range of grassland soils highlighted the critical impact of the microfauna on ecosystem services associated with soil organic matter dynamics. Gamasids slightly amplified the effect of nematodes on microbial metabolic activity,but only in the pastures. This effect was most probably due to the control of nematode abundance. The fact that gamasid addition also augmented the impact of environmental conditions on nematode-induced modulation of soil respiration highlighted the need for including land use differences while evaluating soil fauna contribution to soil processes. To conclude, the differential response of the investigated tritrophic food chain to different grassland management systems suggests that adverse effects of land use intensification on important soil processes such as atmospheric C-release could potentially be reduced by using management methods that preserve essential features of the belowground fo

关键词： CO_2 emission land use microcosm nematodes predatory mites soil fauna soil food webs

Subcellular Localization and In Vivo Interactions of the Arabidopsis thaliana Ethylene Receptor Family Members

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2008年第2期1卷 308-320页

作者： Christopher Grefen Katrin Stadele Kamil Ruzicka Petr Obrdlik klaus Hatter Jakub Horak Zentrum fur Molekularbiologie der Pflanzen Pflanzenphysiologie Universitat Tubingen Auf der Morgenstelle 1 72076 Tubingen Germany Zentrum for Molekularbiologie der Pflanzen Entwicklungsgenetik Universit&t Tubingen Auf der Morgenstelle 3 72076 Tubingen Germany IonGate Biosciences GmbH Industriepark Hochst D 528 65926 Frankfurt am Main Germany

The gaseous phytohormone ethylene regulates many developmental processes and responses to environmental conditions in higher plants. In Arabidopsis thaliana, ethylene perception and initiation of signaling are mediated by a family of five receptors which are related to prokaryotic two-component sensor histidine kinases. The transient ex- pression of fluorescence-tagged receptors in tobacco （Nicotiana benthamiana） epidermal leaf cells demonstrated that all ethylene receptors are targeted to the ER endomembrane network and do not localize to the plasmalemma. In support of in planta overlay studies, the ethylene receptors form homomeric and heteromeric protein complexes at the ER in living plant cells, as shown by membrane recruitment assays. A comparable in vivo interaction pattern was found in the yeast mating-based split-ubiquitin system. The overlapping but distinct expression pattern of the ethylene receptor genes suggests a differential composition of the ethylene receptor complexes in different plant tissues. Our findings may have crucial functional implications on the ethylene receptor-mediated efficiency of hormone perception, induction of signaling, signal attenuation and output.

关键词： PLANT hormones ETHYLENE ARABIDOPSIS thaliana PROKARYOTES PLANT cells & tissues

Designing waste rock barriers by advanced numerical modelling

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2019年第3期11卷 659-675页

作者： klaus Thoeni Martin Servin Scott W.Sloan Anna Giacomini Centre for Geotechnical Science and Engineering The University of NewcastleCallaghanNSW 2308Australia UMIT Research Lab Umea niversityUmeaSE-90187Sweden

Design of waste rock barriers forming safety berms for haul trucks requires knowledge of complex interactions which cannot readily be tested by physical *** advanced numerical model based on non-smooth multi-domain mechanics is presented together with model calibration using limited fullscale experimental *** rock is represented by spherical particles with rolling resistance,and an ultra-class haul truck is represented by a rigid multibody system interconnected with mechanical *** model components are first calibrated and then the calibrated model is used for simulating various collision scenarios with different approach conditions and safety berm *** predictions indicate that the width of the berm is most critical for efficiently stopping a runaway *** model can also predict if a certain berm geometry is capable of stopping a runaway *** are summarised in a series of diagrams intended for use as design guidelines by practitioners and engineers.

关键词： Discrete element method(DEM) Multibody dynamics(MBD) Non-smooth multi-domain dynamics Granular materials Ultra-class haul truck Safety berm Surface mining