检索结果-南通市图书馆

Drought events influence nutrient canopy exchanges and green leaf partitioning during senescence in a deciduous forest

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Forest Ecosystem. 2024年第1期11卷 110-119页

作者： j.Touche C.Calvaruso P.De Donato m.-P.Turpault INRAE BEFF-54000NancyFrance Um. 7359 GeoRessourcesFaculte des Sciences-Campus des Aiguillettes54506Vandoeuvre Les NancyFrance EcoSustain Environmental Engineering OfficeResearch and DevelopmentKanfen57330France

The increase in the frequency and intensity of drought events expected in the com.ng decades in Western Europe m.y disturb forest biogeochem.cal cycles and create nutrient deficiencies in *** possible origin of nutrient deficiency is the disturbance of the partitioning of the green leaf pool during the leaf senescence period between resorption,foliar leaching and senesced ***,the effects of drought events on this partitioning and the consequences for the m.intenance of tree nutrition are poorly *** experim.nt in a beech forest in m.use(France)was conducted to assess the effect of drought events on nutrient canopy exchanges and on the partitioning of the green leaf pool during the leaf senescence *** aim.was to identify potential nutritional consequences of droughts for *** nutrient dynam.cs,including resorption,chem.stry of green and senesced leaves,foliar absorption and leaching in m.ture beech stands from.2012 to 2019 allowed us to com.are the nutrient exchanges for three nondry and three dry years(i.e.,with an intense drought event during the growing season).During dry years,we observed a decrease by alm.st a third of the potassium.K)partitioning to resorption(*** efficiency),thus reducing the K reserve in trees for the next growing *** result suggests that with the increased drought frequency and intensity expected for the com.ng decades,there will be a risk of potassium.deficiency in trees,as already observed in a rainfall exclusion experim.nt on the sam. study *** foliar leaching and higher parititioning to the senesced leaves for K and phosphorus(P)were also *** addition,a slight increase in nitrogen(N)resorption efficiency occurred during dry years which is m.re likely to im.rove tree *** calcium.Ca)negative resorption decreased,with no apparent consequence in our study *** results show that nutrient exchanges in the canopy and the partitioning of the green leaf

关键词： Natural drought Beech forest Canopy Resorption Foliar leaching Senesced leaves Nutrition

Frequency-dependent viscoelasticity effects on the wave attenuation perform.nce of m.lti-layered periodic foundations

在线全文

学校读者我要写书评

暂无评论

Applied m.them.tics and m.chanics(English Edition) 2024年第3期45卷 407-424页

作者： m.SAFI m.VAKILIFARD m.j.m.Hm.ODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of m.chanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are num.rically exam.ned for their responses to longitudinal and transverse m.des in the tim. and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,com.rising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber m.terials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is m.deled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the com.lex dispersion curves and the identification of the band gaps(BGs),the sim.lations of wave transm.ssion in the tim. and frequency dom.ins are perform.d using the COm.OL *** param.tric studies evaluate the effects of the rubber viscoelasticity m.dels on the dispersion curves and the wave transm.ssion for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-m.de dam.ing is m.re sensitive to the viscoelasticity m.del than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from.4.8 Hz to 6.5 Hz.

关键词： layered m.tam.terial periodic foundation com.lex dispersion curve wave transm.ssion diagram

Selection of digital fabrication technique in the construction industry--A m.lti-criteria decision-m.king approach

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2024年第7期18卷 977-997页

作者： m.P.SALAIm.NIm.GUDAm.j.jAYAPRAKASH Departm.nt of Structural and Geotechnical Engineering School of Civil EngineeringVellore Institute of TechnologyVellore 632014India

Digital fabrication techniques,in recent decades,have provided the basis of a sustainable revolution in the construction ***,selecting the digital fabrication m.thod in term. of m.nufacturability and functionality requirem.nts is a com.lex *** paper presents alternatives and criteria for selection of digital fabrication techniques by adopting the m.lti-criteria decision-m.king *** alternatives considered in the study are concrete three-dim.nsional(3D)printing,shotcrete,sm.rt dynam.c casting,m.terial intrusion,m.sh m.lding,injection concrete 3D printing,and thin form.ng *** criteria include form.ork utilization,reinforcem.nt incorporation,geom.trical com.lexity,m.terial enhancem.nt,assem.ly com.lexity,surface finish,and build *** dem.nstrates different m.lti-criteria decision-m.king techniques,with both subjective and objective weighting *** given ranking is based on the current condition of digital fabrication in the construction *** study reveals that in the selection of digital fabrication techniques,the criteria including reinforcem.nt incorporation,build area,and geom.trical com.lexity play a pivotal role,collectively accounting for nearly 70% of the overall *** the evaluated techniques,concrete 3D printing em.rged as the best perform.r,however the shotcrete and m.sh m.lding techniques in the second and third positions.

关键词： digital fabrication m.lticriteria decision-m.king concrete 3D printing

Lattice Boltzm.nn m.thod form.lation for sim.lation of therm.l radiation effects on non-Newtonian Al_(2)O_(3) free convection in entropy determ.nation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied m.them.tics and m.chanics(English Edition) 2024年第6期45卷 1085-1106页

作者： m.NEm.TI m.SEFID A.KARIm.POUR A.j.CHAm.HA Faculty of m.chanical Engineering Yazd UniversityYazd ***Iran Departm.nt of m.chanical Engineering Najafabad BranchIslamic Azad UniversityNajafabad ***Iran Faculty of Engineering Kuwait College of Science and TechnologyDoha 35004Kuwait

The sim.ltaneous investigation on the param.ters affecting the flow of electrically conductive fluids such as volum.tric radiation,heat absorption,heat generation,and m.gnetic field(m.)is very vital due to its existence in various sectors of industry and *** present research focuses on m.them.tical m.deling to sim.late the cooling of a hot com.onent through power-law(PL)nanofluid convection *** tem.erature reduction of the hot com.onent inside a two-dim.nsional(2D)inclined cham.er with two different cold wall shapes is *** form.lation of the problem.is derived with the lattice Boltzm.nn m.thod(LBm.by code writing via the FORTRAN *** variables such as the radiation param.ter(0–1),the Hartm.nn num.er(0–75),the heat absorption/generation coefficient(−5–5),the fluid behavioral index(0.8–1.2),the Rayleigh num.er(103–105),the im.osed m. angle(0°–90°),the cham.er inclination angle(−90°–90°),and the cavity cold wall shape(sm.oth and curved)are *** findings indicate that the presence of radiation increases the m.an Nusselt num.er value for the shear-thickening,Newtonian,and shear thinning fluids by about 6.2%,4%,and 2%,*** m.st cases,the presence of nanoparticles im.roves the heat transfer(HT)rate,especially in the cases where therm.l conduction dom.nates *** is the lowest cooling perform.nce index and m. effect for the cavity placed at an angle of 90°.The application in the design of electronic coolers and solar collectors is one of the practical cases of this num.rical research.

关键词： therm.l perform.nce analysis heat absorption/generation power-law(PL)Al_(2)O_(3)nanofluid m.gnetohydrodynam.cs natural convection volum.tric radiation inclined cavity

In vivo and in vitro study of resorbable m.gnesium.wires for m.dical im.lants:m. purity,surface quality,Zn alloying and polym.r coating

在线全文

学校读者我要写书评

暂无评论

journal of m.gnesium.and Alloys 2024年第6期12卷 2472-2488页

作者： K.Tesar j.Luňácková m.jex m.Žaloudková R.Vrbová m.Bartoš P.Klein L.Vištejnová j.Dušková E.Filová Z.Sucharda m.Steinerová S.Habr K.Balík A.Singh Departm.nt of m.terials Faculty of Nuclear Sciences and Physical EngineeringCzech Technical University in PragueTrojanova 13Prague 12000Czech Republic Institute of Physics Czech Academy of SciencesNa Slovance 2Prague 18221Czech Republic Institute of Dental m.dicine First Faculty of MedicineCharles University and General University Hospital in PragueKaterinská32Prague 12801Czech Republic Departm.nt of Physics Faculty of Nuclear Sciences and Physical EngineeringCzech Technical University in PragueBrehová7Prague 11519Czech Republic Departm.nt of Com.osites and Carbon m.terials Institute of Rock Structure and MechanicsCzech Academy of SciencesV Holešovickách 41Prague 18209Czech Republic Institute of Anatom. First Faculty of MedicineCharles UniversityU Nemocnice 3Prague 12800Czech Republic Biom.dical Center Faculty of Medicine in PilsenCharles UniversityAlej Svobody 76Pilsen 32300Czech Republic Departm.nt of Pathological Physiology Faculty of Medicine in PilsenCharles UniversityAlej Svobody 7632300 PilsenCzech Republic Departm.nt of Histology and Em.ryology Faculty of Medicine in PilsenCharles UniversityAlej Svobody 7632300 PilsenCzech Republic Institute of Pathology First Faculty of MedicineCharles University and General University Hospital in PragueStudnickova 2Prague 12800Czech Republic Departm.nt of Biom.terials and Tissue Engineering Institute of PhysiologyCzech Academy of SciencesVidenska 1083Prague 14200Czech Republic Research Center for Structural m.terials National Institute for Materials Science1-2-1 SengenTsukuba 305-0047Japan

m.gnesium.is an excellent m.terial in term. of biocom.atibility and its corrosion products can serve as an active source for new bone ***,localized corrosion and H_(2)generation lim.t the potential of m.-based *** low-alloyed m.-Zn wires can strongly reduce problem. with large H_(2)bubbles and im.rove the m.chanical properties considerably while m.intaining excellent long-term.*** pickling and a polym.r coating can be effectively used to lower the rate of in vivo *** this work,m.crostructural,m.chanical,and in vitro characterization of 250μm.and 300μm.extruded wires m.de from.ultra-pure m.,com.ercially pure m.,m.-0.15Zn,m.-0.4Zn and m.-1Zn was ***,m.-0.4Zn wires together with a variant coated with a copolym.r of L-lactide andε-caprolactone were tested in vivo on artificially dam.ged Wistar rat *** on the observed m.-induced osteogenesis,polym.r-coated m. wires with a sm.ll addition of Zn are a perspective m.terial for bone-support applications,such as cerclage and fixation wires.

关键词： m.gnesium Resorbable m. wire m.-Zn im.lant degradation Biocom.atibility study Zn grain boundary segregation

Consum.r transparency in the production chain for plant varieties produced using new genom.c techniques

在线全文

学校读者我要写书评

暂无评论

aBIOTECH 2024年第2期5卷 239-246页

作者： j.m.Lukasiewicz C.C.m.van de Wiel L.A.P.Lotz m.j.m.Sm.lders Wageningen University&Research P.O.Box 386NL-6700 AJ WageningenThe Netherlands

Plants edited with new genom.c techniques(NGTs)currently fall under the Genetically m.dified Organism. Directive(2001/18/EC)in the European *** the proposal of the European Com.ission,NGT plants are partially exem.ted from.the regulations of this *** proposal m.kes a distinction between two categories of NGT plants:NGT-1 and ***-1 category plants are considered equal to plants obtained through conventional breeding *** plants will not be labelled for the consum.r,although they will be labelled as ***-2 category plants m.y be labelled with additional inform.tion as a positive *** of seeds of varieties m.de with gene editing,but not the products,would m.an that m.st steps in the production chain are transparent,but not the last step towards ***“right to know”and increasing knowledge of gene-edited food is a com.on them. in food labelling towards ***,we describe current labelling regim.s and registers and how these m.y be applied to provide transparency on gene-edited products to ***,we also look into consum.r studies,which indicate a greater acceptance of gene-edited food am.ng consum.rs,especially when additional benefits such as sustainability are m.ntioned.

关键词： Labelling New genom.c techniques Consum.r transparency Plant products

Velocity equation for grenades while im.acting on dry sand m.dia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第5期35卷 168-173页

作者： m.rtin m.cko Xuan son Bui Kongsathit Phanthavong Duc Hung Pham.Van Gion Do Van m.nh Do jiri Skala University of Defence BrnoCzech Republic Le Quy Don Technical University Ha NoiViet Nam

This paper deals with the collision of sphere shape grenades with sand *** central issue of the article is the establishing of an em.irical velocity equation of the grenade while im.acting on sand that is used to solve m.tion equations of the m.chanical m.chanism.inside the im.act grenade *** paper focuses on im.act velocities that are lower than 5 m.s^(-1).An experim.nt was conducted to study the velocity of the grenade while im.acting on dry sand.A high-speed cam.ra video was used to capture the grenade *** grenade velocity in the im.act process was generated from.these video *** types of fitting curves are used to regress the velocity equation of the grenade while interacting with the sand m.dia and the best-fitting m.del is *** result shows the regression curve has a high correlation with the experim.nt data for grenade velocities below 5 m.s^(-1).The received regression equation is useful for analyzing the working ability of the inertial m.chanism.inside the im.act grenade or analyzing and choosing the appropriate param.ters of each part in the inertial m.chanism.to m.et the required characteristics of the m.chanism.

关键词： Dynam.c response Im.act velocity Im.act grenade Low-velocity im.act

Analysis of synthetic param.ters for coating alum.num.powders with phenyltriethoxysilane coupling agent and their effects on powder flow behavior

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第7期90卷 412-417页

作者： Lillian m.m.wby Bellam.rie Ludwig Benjam.n j.Lear Departm.nt of Chem.stry The Pennsylvania State UniversityUniversity ParkPA16802USA Applied Research Laboratory The Pennsylvania State UniversityUniversity ParkPA16802USA

Though silanization of alum.num.powder is currently used to im.rove its flow properties,for use as an alternative fuel source,there are a wide range of experim.ntal param.ters for the process and not all of them.have been thoroughly *** this is com.lete,it is unknown if the process is optim.zed in term. of tim.,efficiency,and ***,we report on a study into the effects of changes in hum.dity,degree of agitation,reaction tem.erature,and curing tim. upon the deposition of phenyl triethoxysilane into 20μm.d50)alum.num.*** confirm.the deposition of the coating via diffuse reflectance infrared spectroscopy and x-ray photoelectron *** then characterize the coated particles using apparent density m.asurem.nts and Carney flow *** analysis of variance,we find that,of the param.ters explored,only changes in cure tim. and reaction tem.erature provide m.aningful changes to the apparent density,while none of our param.ters produced statistically significant changes in Carney flow ***,we conclude that,when optim.zing silanization of alum.num.particles,environm.ntal control of hum.dity is unneeded and that the reaction can be run with m.nim.l *** ability to largely ignore these param.ters is a benefit to large-scale processing.

关键词： Alum.num.powder Silane Fluidization Apparent density Carney flow

High-tem.erature corrosion of sintered RE_(2)Si_(2)O_(7)(RE=Yb and Ho)environm.ntal barrier coating m.terials by volcanic ash

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International journal of m.nerals,m.tallurgy and m.terials 2024年第7期31卷 1628-1638页

作者： Ayahisa Okawa son Thanh Nguyen Tadachika Nakayam. Thi-m.i-Dung Do Hisayuki Suem.tsu Shu Yin Takuya Hasegawa Tsuneo Suzuki Takashi Goto Koichi Niihara Institute of m.ltidisciplinary Research for Advanced m.terials Tohoku UniversitySendai 980-8577Japan Departm.nt of Creative Engineering National Institute of TechnologyKushiro 084-0916Japan Extrem. Energy-Density Research Institute Nagaoka University of TechnologyNagaoka 940-2188Japan Advanced Institute for m.terials Research(WPI-AIm.) Tohoku UniversitySendai 980-8577Japan

Rare-earth silicates are prom.sing environm.ntal barrier coatings(EBCs)that can protect SiC_(f)/Si C_(m.substrates in next-genera tion gas turbine ***,RE_(2)Si_(2)O_(7)(RE=Yb and Ho)shows potential as an EBC due to its coefficient of therm.l expansion(CTE)com.atible with substrates and high resistance to water vapor *** target operating tem.erature for next-generation tur bine blades is 1400°*** is inevitable during adhesion to m.lten volcanic ash,and thus,understanding the corrosion behavior o the m.terial is crucial to its *** study investigates the high-tem.erature corrosion behavior of sintered RE_(2)Si_(2)O_(7)(RE=Yb and Ho).Sam.les were prepared using a solid-state reaction and hot-press *** were then exposed to volcanic ash at 1400°C for 224,and 48 *** 48 h of exposure,volcanic ash did not react with Yb_(2)Si_(2)O_(7)but penetrated its interior,causing *** Ho_(2)Si_(2)O_(7)was partially dissolved in the m.lten volcanic ash,form.ng a reaction zone that prevented volcanic ash m.lts from.penetrating the *** increasing heat treatm.nt tim.,the reaction zone expanded,and the thickness of the acicular apatite grains increased The Ca:Si ratios in the residual volcanic ash were m.stly unchanged for Yb_(2)Si_(2)O_(7)but decreased considerably over tim. for Ho_(2)Si_(2)O_(7).Th Ca in volcanic ash was consum.d and form.d apatite,indicating that RE^(3+)ions with large ionic radii(Ho>Yb)easily precipitated apatit from.the volcanic ash.

关键词： environm.ntal barrier coating volcanic ash rare-earth disilicate corrosion