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Soil carbon characterization along the profile of two forest soils under Quercus pyrenaica

journal of Forestry research 2020年第2期31卷 591-600页

作者： A.P.fernandez-Getino j.L.Alonso-Prados M.I.Santin-Montanya UPF-DTEVPF Instituto Nacional de Investigacion y Tecnologia Agraria y AlimentariaINIACtra.A Corunakm 7.528040 MadridSpain Dpto.Proteccion Vegetal Instituto Nacional de Investigacion y Tecnologia Agraria y AlimentariaINIACtra.A Corun akm 7.528040 MadridSpain

In light of concerns over climate change and increasing levels of CO2 in the atmosphere,it is of importance to investigate soil organic matter in Mediterranean forests at a profile ***-depth studies of the organic fraction are also of interest to improve understanding of carbon balance and to facilitate modelling of carbon fixation in forest *** research evaluates the relationships between diverse parameters such as colour,content,and form of soil organic matter(SOM).Two Quercus pyrenica ecosystems with soils classified as inceptisols with a xeric or dry moisture regime,and developed under a Mediterranean climate in Spain,were used to characterize SOM through the complete sequence of layers of the soil *** differentiating factor between the two ecosystems was slope *** was done using characteristics of humic substances(HS)as indicators of SOM turnover in *** analysis was used to further characterize the humic *** soil colour measurements are a tool for soil type classification and soil organic carbon prediction,the relation between HS colour measured by reflection and by transmission was determined in order to establish a relationship between measurement *** analysis and colour provided evidence of a different level of stabilization of HS from both soils,and between the different *** of humic acids was found to be greater in deeper horizons than in the surface *** inverse relationship between HS colour measured by reflection and by transmission was *** soils showed a clear trend in which horizons presenting lower absorbance numbers showed higher figures of hue and value.A more marked accumulation of humified compounds was found in pedons,(the smallest unit or volume of soil that contains all the soil types),in the less steep *** might be explained in terms of the physiographic position affecting infiltration behavior and exposure to runoff.

关键词： Organic matter turnover Colour humic substance(HS)by reflection Colour HS by transmission Humification index Mediterranean Quercus species

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Large deformations in deep tunnels excavated in weak rocks:Study on Y-Basque high-speed railway tunnels in northern Spain

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Underground Space 2021年第6期6卷 636-649页

作者： Cosimo Iasiello juan Carlos Guerra Torralbo Cesar Torrero fernandez IrP biuro projektow sp.z.o.o. al.Jana Pawla Ⅱ 1100-828 WarszawaPoland European University of Madrid Calle Tajos/n 28670 Villaviciosa de OdonMadridSpain Ayesa Ingenierıa S.A. Paseo Castellana 9128046 MadridSpain

Designing the support system for a deep tunnel in weak rock is always challenging,because a misjudgment of real rock behavior can lead to *** the construction of the Legutiano tunnel,which belongs to the high-speed railway network named Y-Basque in Spain,the measured convergences exhibited large deformations,which were significantly higher than those in the detailed *** first glance,these deformations were associated with squeezing,as the tunnel was excavated in flysch-shales and limonite with a maximum cover of approximately 360 *** aim of this study is to perform a retrofit analysis to compare the most popular empirical and analytical approaches for evaluating the squeezing effect,using geotechnical data pertaining to other tunnels excavated in the same area and in the same geological ***,a non-linear finite element analysis,focusing on time-dependent rock behavior,is conducted to reproduce the convergences measured.

关键词： Shales Limonite Squeezing Plaxis Tunnel monitoring

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Self-assembled formation of long, thin, and uncoalesced GaN nanowires on crystalline TiN films

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Nano research 2018年第1期11卷 565-576页

作者： David van Treeck Gabriele Calabrese jelle j. W. Goertz Vladimir M. Kaganer Oliver Brandt Sergio fernandez-Garrido, Lutz Geelhaar PauI-Drude-lnstitut f~r Festk6rperelektronik Leibniz-lnstitut im Forschungsverbund Berlin e.V. Hausvogteiplatz 5-7 I 0117 Berlin Germany

We investigate in detail the self-assembled nucleation and growth of vertically oriented GaN nanowires by molecular beam epitaxy on crystalline TiN films. We demonstrate that this type of substrate allows for the growth of long and thin GaN nanowires that do not suffer from coalescence, a problem common to the growth on Si and other substrates. Only beyond a certain nanowire length that depends on the nanowire density and exceeds here 1.5 bun, coalescence takes place by bundling, i.e. the same process as on Si. By analyzing the nearest neighbor distance distribution, we identify the diffusion-induced repulsion of neighboring nanowires as the main mechanism limiting nanowire density during nucleation on TiN. Since on Si the final density is determined by shadowing of the impinging molecular beams by existing nanowires, it is the difference in adatom surface diffusion that enables the formation of nanowire ensembles with reduced density on TiN. These nanowire ensembles combine properties that make them a promising basis for the growth of core-shell heterostructures.

关键词： nanocolumn gallium nitride nucleation metal substrate coalescence core-shell

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Design,fabrication,characterization and reliability study of CMOS-MEMS Lorentz-force magnetometers

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Microsystems & Nanoengineering 2022年第5期8卷 17-41页

作者： j.j.Valle j.M.Sánchez-Chiva D.Fernández j.Madrenas Department of Electronic Engineering Universitat Politècnica de CatalunyaJordi Girona 1 i 3Edifici C408034 BarcelonaSpain Sorbonne Université CNRSLaboratoire de Recherche en Informatique(LIP6)UMR76064 place Jussieu75005 ParisFrance Institut de Física d’Altes Energies(IFAE) The Barcelona Institute of Science and Technology(BIST)Edifici Cn.Facultat Ciències NordUniversitat Autónoma de Barcelona08193 Bellaterra(Barcelona)Spain

This article presents several design techniques to fabricate micro-electro-mechanical systems(MEMS)using standard complementary metal-oxide semiconductor(CMOS)*** were applied to fabricate high yield CMOS-MEMS shielded Lorentz-force magnetometers(LFM).The multilayered metals and oxides of the back-end-of-line(BEOL),normally used for electronic routing,comprise the structural part of the *** most important fabrication challenges,modeling approaches and design solutions are *** that predict the Q factor,sensitivity,Brownian noise and resonant frequency as a function of temperature,gas pressure and design parameters are presented and validated in characterization tests.A number of the fabricated magnetometers were packaged into Quad Flat No-leads(QFN)*** show this process can achieve yields above 95%when the proper design techniques are *** CMOS not being a process for MEMS manufacturing,estimated performance(sensitivity and noise level)is similar or superior to current commercial magnetometers and others built with MEMS ***,typical offsets present in Lorentz-force magnetometers were prevented with a shielding electrode,whose efficiency is ***,several reliability test results are presented,which demonstrate the robustness against high temperatures,magnetic fields and acceleration shocks.

关键词： Lorentz magnetometer characterization

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Eocene Antarctica:a window into the earliest history of modern whales

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Advances in Polar Science 2019年第3期30卷 293-302页

作者： Mónica r.BUONO r.Ewan FOrDYCE Felix G.MArX Marta S.fernandez Marcelo A.rEGUErO Instituto Patagónico de Geología y Paleontología CCT CONICET-CENPATBvd.Brown 2915U9120ACDPuerto MadrynChubutArgentina Department of Geology University of Otago360 Leith WalkPO Box 56DunedinOtago 9054New Zealand Departments of Paleobiology and Vertebrate Zoology National Museum of Natural HistorySmithsonian InstitutionWashington DCUSA Directorate of Earth and History of Life Royal Belgian Institute of Natural SciencesBrusselsBelgium Department of Geology University of LiègeB18Quartier Agora14 Allée du 6 Aout4000 LiègeBelgium School of Biological Sciences Monash UniversityClaytonAustralia Palaeontology Museums VictoriaMelbourneAustralia CONICET-División Paleontología Vertebrados Unidades de InvestigaciónAnexo MuseoFacultad de Ciencias Naturales y MuseoUniversidad Nacional de La Plata60 y 122B1900FWALa PlataArgentina CONICET-División Paleontología de Vertebrados Museo de La PlataPaseo del Bosque s/nB1900FWALa PlataArgentina Instituto Antártico Argentino(Dirección Nacional del Antártico) 25 de Mayo 11511650San MartínArgentina

The Eocene–Oligocene Southern Ocean is thought to have played a major role in cetacean ***,fossils from its heart—Antarctica—are rare,and come almost exclusively from the Eocene La Meseta and Submeseta formations of Marambio(Seymour)***,we provide a summary and update of this crucial fossil assemblage,and discuss its relevance in the broader context of cetacean *** date,Eocene specimens from Antarctica include basilosaurids,a group of archaic stem cetaceans that had already fully adapted to life in water;and the archaic toothed mysticete Llanocetus,the second oldest crown cetacean on record(ca.34 Ma).This Eocene co-occurrence of stem and crown cetaceans is highly unusual,and otherwise only observed in *** related,at least some of the Antarctic species appear to be different from,and notably larger than their Peruvian counterparts,suggesting an early differentiation of the high latitude cetacean fauna.

关键词： Marambio(Seymour)Island Basilosauridae Mysticeti evolution

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Pre-fire aboveground biomass, estimated from LiDAr, spectral and field inventory data, as a major driver of burn severity in maritime pine (Pinus pinaster) ecosystems

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Forest Ecosystems 2022年第2期9卷 234-246页

作者： jose Manuel fernandez-Guisuraga Susana Suarez-Seoane Paulo MFernandes Victor fernandez-Garcia Alfonso fernandez-Manso Carmen Quintano Leonor Calvo Area of Ecology Department of Biodiversity and Environmental ManagementFaculty of Biological and Environmental SciencesUniversity of Leon24071LeonSpain Centro de Investigacao e de Tecnologias Agroambientais e Biologicas Universidade de Tras-os-Montes e Alto Douro5000-801Vila RealPortugal Department of Organisms and Systems Biology(Ecology Unit)and research Unit of Biodiversity(IMIB UO-CSIC-PA)University of OviedoOviedoMieresSpain Agrarian Science and Engineering Department School of Agricultural and Forestry EngineeringUniversity of Leon24400PonferradaSpain Electronic Technology Department School of Industrial EngineeringUniversity of Valladolid47011ValladolidSpain Sustainable Forest Management research Institute University of Valladolid-Spanish National Institute for Agriculture and Food Research and Technology(INIA)34004PalenciaSpain

Background:The characterization of surface and canopy fuel loadings in fire-prone pine ecosystems is critical for understanding fire behavior and anticipating the most harmful ecological effects of ***,the joint consideration of both overstory and understory strata in burn severity assessments is often *** aim of this work was to assess the role of total,overstory and understory pre-fire aboveground biomass(AGB),estimated by means of airborne Light Detection and ranging(LiDAr)and Landsat data,as drivers of burn severity in a megafire occurred in a pine ecosystem dominated by Pinus pinaster *** the western Mediterranean ***:Total and overstory AGB were more accurately estimated(r^(2) equal to 0.72 and 0.68,respectively)from LiDAr and spectral data than understory AGB(r^(2)=0.26).Density and height percentile LiDAr metrics for several strata were found to be important predictors of *** severity responded markedly and non-linearly to total(r^(2)=0.60)and overstory(r ^(2)=0.53)AGB,whereas the relationship with understory AGB was weaker(r ^(2)=0.21).Nevertheless,the overstory plus understory AGB contribution led to the highest ability to predict burn severity(rMSE=122.46 in dNBr scale),instead of the joint consideration as total AGB(rMSE=158.41).Conclusions:This study novelty evaluated the potential of pre-fire AGB,as a vegetation biophysical property derived from LiDAr,spectral and field plot inventory data,for predicting burn severity,separating the contri-bution of the fuel loads in the understory and overstory strata in Pinus pinaster *** evidenced relationships between burn severity and pre-fire AGB distribution in Pinus pinaster stands would allow the implementation of threshold criteria to support decision making in fuel treatments designed to minimize crown fire hazard.

关键词： Aboveground biomass Burn severity Landsat LiDAr Pinus pinaster

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Lignocellulose as an insoluble fiber source in poultry nutrition:a review

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journal of Animal Science and Biotechnology 2021年第4期12卷 1237-1251页

作者： Ilen röhe jürgen Zentek Department of Veterinary Medicine Institute of Animal NutritionFreie Universität Berlin14195 BerlinGermany

Extensive research in recent years into the use of various fiber sources in poultry nutrition has led to the perception that dietary fiber is more than a simple diet *** studies showed that the feeding of insoluble fiber sources such as oat hulls,sunflower hulls or wood shavings may affect digestive physiology and function improving chickens health and growth *** this context,the effect of lignocellulose as an insoluble dietary fiber source is increasingly being *** is a component of plant cell walls and consists mainly of the insoluble carbohydrate polymers cellulose and hemicelluloses as well as the phenolic polymer *** is chemically and physicochemically different from other insoluble fiber sources and thus possibly has different effects on poultry compared to traditional fiber *** studies investigated the effect of dietary lignocellulose on growth performance,nutrient digestibility,gastrointestinal tract development and intestinal microbiota in broilers and laying *** differed in terms of feed formulation and lignocellulose inclusion level as well as products of different suppliers were *** results obtained are inconsistent;beneficial,indifferent or detrimental effects of feeding lignocellulose were observed,so that a final assessment of lignocellulose as a“novel”insoluble fiber source is *** review article summarizes the results of studies in connection with the feeding of lignocellulose to poultry,compares them with those that have used other insoluble fiber sources and illuminates the possible mechanisms of action.

关键词： Fiber Growth performance Gut health Gut morphology Lignocellulose Microbiota Nutrient digestibility Poultry

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Considerations for effective ground support in evaporites

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International journal of Mining Science and Technology 2019年第1期29卷 113-118页

作者： j.r.Nopola C.A.Vining rESPEC

Evaporites, such as salt and potash, pose unique problems to ground-support designs that are not encountered in other rock types. Evaporites are subject to continual creep and no amount of ground support can successfully arrest this process. Common ground-support techniques that are useful for most rock types may reduce the effective life of bolts in evaporite mines and create unseen hazards. A different approach to ground support must be applied to provide long-term support in areas where high creep rates are present. The goal of effective ground-support designs in these situations is not to contain and prevent the rock from moving; rather, the ground-support design must be able to move along with the rock and contain any fully detached slabs until additional remediation measures can be *** most appropriate ground-support designs will consider the expected movement of the rock and the duration that the area needs to remain accessible.

关键词： Ground support Ground control rock mechanics And salt mechanics

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Strain gradient plasticity: energetic or dissipative?

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Acta Mechanica Sinica 2015年第4期31卷 465-472页

作者： N.A.Fleck j.r.Willis Department of Engineering University of Cambridge Department of Applied Mathematics and Theoretical Physics University of Cambridge

Abstract For an infinite slab of strain gradient sensitive material subjected to plane-strain tensile loading, compu- tation established and analysis confirmed that passivation of the lateral boundaries at some stage of loading inhibits plastic deformation upon further loading. This result is not surprising in itself except that, remarkably, if the gradient terms contribute to the dissipation, the plastic deformation is switched off completely and only resumes at a clearly defined higher load, corresponding to a total strain ec, say. The analysis presented in this paper confirms the delay of plastic deformation following passivation and determines the exact manner in which the plastic flow resumes. The plastic strain rate is continuous at the exact point ec of resumption of plastic flow and, for the first small increment Ae = e - ec in the imposed total strain, the corresponding increment in plastic strain, AeP, is proportional to （Ae）2. The constant A in the relation AeP（0） = A（Ae）2, where AeP（0） denotes the plastic strain increment at the centre of the slab, has been determined explicitly; it depends on the hardening modulus of the material. The presence of energetic gradient terms has no effect on the value of ec unless the dissipative terms are absent, in which case passivation reduces the rate of plastic deformation but introduces no delay. This qualitative effect of dissipative gradient terms opens the possibility of experimen- tal discrimination of their presence or absence. The analysisemploys an incremental variational formulation that is likely to find use in other problems.

关键词： Strain gradient plasticity Boundary passivation Incremental variational principle

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SECOND-OrDEr INTErACTION OF IrrEGULAr WAVES WITH A TrUNCATED COLUMN

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Acta Mechanica Sinica 1997年第2期13卷 130-142页

作者： j.B.Huang r.EatockTaylor Department of Engineering Science University of OxfordParks RoadOxfordOX1 3PJUK

A complete semi-analytical solution is obtained for second-order diffraction of plane bichromatic waves by a fixed truncated circular *** fluid domain is divided into interior and exterior *** the exterior region,the second-order velocity potential is expressed in terms of‘locked-wave’and‘free-wave’ components,both are solved using Fourier and eigenfunction *** re- sulting‘locked wave’potential is expressed by one-dimensional Green's integrals with oscillating *** order to increase computational efficiency,the far-field part of the integrals are carried out *** in both regions are matched on the interface by the potential and its normal derivative continuity *** on the present approach,the sum-and difference-frequency potentials are efficiently evaluated and are used to generate the quadratic transfer functions which correlates the incident wave spectrum with second-order forcing spectrum on the *** sum-frequency QTFs for a TLP column are present,which are compared for some frequency pairs with those from a fully numerical *** agreement has been *** spectra for a case study TLP column,generated using the semi-analytical solution are *** given are the results for nonlinear wave field around the column.

关键词： marine hydrodynamics nonlinear wave force wave-structure interaction second-order wave diffraction

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