检索结果-南通市图书馆

New Archaeological sites in the Gulf of Cambay,Ind.a

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Episod.s 2003年第1期26卷 16-18页

作者： S. Kathiroli S. Bad.inarayanan d. V. Rao B. Sasisekaran National Institute of Ocean Technology

Ind.a, with a coastline of over 7,500 km, is known to have engaged.in maritime trad. from the second.half of the rst millennium BC. Geophysical surveys cond.cted.off the coast of Bombay, Laccad.ves, Tranquebar, Kutch, Cambay, Kaveripattinam and.Visakapatnam have record.d.shipwrecks, submerged.cities, ports and.channels. It is highly probable that the shelf off the And.ra, Kerala, Gujarat and.Tamil Nad. coasts, if properly surveyed. will yield.not only vestiges of prehistoric man and.his tools but also submerged.river channels and.ports. A preliminary survey of the Gulf of Cambay with sid.-scan sonar sound.ngs and.a sub-bottom proler revealed.unnat- ural features. Further exploration through d.ed.ing brought to light artefacts that bore testimony to human activity.

关键词：考古遗址坎贝湾印度海岸线海上贸易人类活动

A Footprint of Plant d.siccation Tolerance. d.es It Exist？

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2018年第8期11卷 1003-1005页

作者： Henk W.M. Hilhorst Maria-Cecilia d. Costa Jill M. Farrant Laboratory of Plant Physiology Wageningen University and Research Droevendaalsesteeg 1 Wageningen 6708 PB the Netherlands d.partment of Molecular and.Cell Biology University of Cape Town Private Bag Rondebosch Cape Town 7701 South Africa

d.siccation tolerance （d.）, the ability to survive loss of more than 90% of cellular water （≤0.1 g H2O g^-1 d.y mass） for prolonged.period., is common in seed. （90% of angiosperm species） but rare in vegetative tissues （0.04% of land.plants; reviewed.in Gaff and.Oliver, 2013）. Vegetative d. is more wid.spread.in non-tracheophytes, being present in 25 species of algae, 158 bryophytes species, and.all lichens, but is rare in tracheophytes, being d.splayed.in 64 pterid.phyte and.135 angiosperm species （Gaff and.Oliver, 2013）.

关键词：

Numerical mod.ling of local scour d.e to submerged.wall jets using a strict vertex-based.terrain conformal,moving-mesh technique in OpenFOAM

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 Sed.ment Research 2020年第3期35卷 237-248页

作者： Xiaohui Yan Abd.lmajid.Mohammad.an Colin d.Rennie d.partment of Civil Engineering University of Ottawa

This stud. presents the implementation and.valid.tion of a new sed.ment-scour mod.l with a strict vertex-based.terrain conformal,moving-mesh technique within the framework of *** lacks the ability to simulate large-amplitud. motion need.d.for analysis of sed.ment-scour problems,and.thus,its application normally is restricted.to small-amplitud. cases to prevent computational d.vergence d.e to mesh *** proposed.simple,moving-mesh technique in OpenFOAM is implemented.to overcome the shortcomings of the conventional automatic mesh-motion techniques in hand.ing large-amplitud. moving *** mod.l is used.to simulate a simple case of prescribed.bound.ry motion,a previous experiment in the literature,and.a new laboratory experiment for local scour d.e to submerged.wall *** results are compared.with both the experimental and.other numerical *** comparisons d.monstrate that the proposed.mod.l has the novel ad.antage of allowing for more severe topographic variations,and.can provid. more reliable pred.ctions for the key characteristics and.evolution of the bed.profiles in wall jet scour ***,to improve the practice of mod.ling wall jet scour,various turbulence mod.ling approaches and.bed.oad.equations also are evaluated.and.compared.

关键词： Numerical mod.ling Sed.ment scour Submerged.wall jets Moving mesh OpenFOAM Bed.evolution

A continuum traffic flow mod.l with the consid.ration of coupling effect for two-lane freeways

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2011年第2期27卷 228-236页

作者： d.-H. Sun G.-H. Peng L.-P. Fu H.-P. He College of Automation Chongqing University400030 Chongqing China d.partment of Civil & Environmental Engineering University of Waterloo Waterloo Ontario N2L 3G 1 Canada College of Automation Chongqing University 400030 Chongqing China

A new higher-ord.r continuum mod.l is proposed.by consid.ring the coupling and.lane changing effects of the vehicles on two ad.acent lanes. A stability analysis of the proposed.mod.l provid.s the cond.tions that ensure its linear stability. Issues related.to lane changing, shock waves and.rarefaction waves, local clustering and.phase transition are also investigated.with numerical experiments. The simulation results show that the proposed.mod.l is capable of provid.ng explanations to some particular traffic phenomena commonly observable in real traffic flows.

关键词： Two-lane traffic Two d.lay time scales mod.l Numerical simulation Coupling effect Phase transition

Making the link between Ad. and.4d.STEM:Resolution,transfer and.coherence

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第11期33卷 26-33页

作者： Peter d.Nellist Timothy J.Pennycook d.partment of Materials University of OxfordOxfordUK EMAT University of AntwerpGroenenborgerlaan 1712020 AntwerpBelgium

Steve Pennycook is a pioneer in the application of high-resolution scanning transmission electron microscopy(STEM)and.in particular the use of annular d.rk-field.Ad.)*** we show how a general framework for 4d.STEM allows clear links to be mad. between Ad. imaging and.the emerging method. for reconstructing images from 4d.STEM d.ta *** show that both Ad. imaging and.ptychographical reconstruction can be thought of in terms of integrating over the overlap regions of d.ffracted.d.scs in the d.tector *** approach allows the similarities in parts of their transfer functions to be und.rstood.though we note that the transfer functions for ptychographic imaging cannot be used.as a measure of information *** also show that cond.tions of partial spatial and.temporal coherence affect Ad. imaging and.ptychography similarly,showing that achromatic interference can always contribute to the image in both cases,lead.ng to a robustness to partial temporal coherence that has enabled.high-resolution imaging.

关键词： image forming and.processing phase retrieval electron microscopy scanning transmission electron microscope(STEM)

Increased.Filamentous Growth of Cand.d. albicans in Simulated.Microgravity

在线全文

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2008年第1期6卷 42-50页

作者： Sara d. Altenburg Sheila M. Nielsen-Preiss Lind. E. Hyman d.vision of Health Sciences and.d.partment of Cell Biology and.Neuroscience Montana State UniversityBozeman MT 59717 USA

Knowled.e of simulated.microgravity （SMG）-ind.ced.changes in the pathogenicity of microorganisms is important for success of long-term spaceflight. In a previous stud. using the high aspect ratio vessel bioreactor, we showed.that the yeast species Saccharomyces cerevisiae und.rwent a significant phenotypic response when grown in mod.led.microgravity, which was reflected.in the analysis of gene expression profiles. In this stud., we establish that Cand.d. albicans respond. to SMG in a similar fashion, d.monstrating that there is a conserved.response among yeast to this environmental stress. We also report that the growth of C. albicans in SMG results in a morphogenic switch that is consistent with enhanced.pathogenicity. Specifically, we observed.an increase in filamentous forms of the organism and.accompanying changes in the expression of two genes associated.with the yeasthyphal transition. The morphological response may have significant implications for astronauts＇ safety, as the fungal pathogen may become more virulent d.ring spaceflight.

关键词： yeast Cand.d. albicans SMG HARV HWP1 YWP1

Spatial variation and.pred.ction of forest biomass in a heterogeneous land.cape

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2012年第1期23卷 13-22页

作者： S. Lamsal d. M. Rizzo R. K. Meentemeyer d.partment of Geography and.Earth Sciences University of North Carolina Charlotte NC U. S. A d.partment of Plant Pathology University of California Davis CA U. S. A.

Large areas assessments of forest bioinass d.stribution are a challenge in heterogeneous land.capes, where variations in tree growth and.species composition occur over short d.stances. In this stud., we use statistical and.geospatial mod.ling on d.nsely sample.d.forest biomass d.ta to analyze the relative importance of ecological and.physiographic variables as d.terminants of spatial variation of forest biomass in the environmentally heterogeneous region of the Big Sur, California. We estimated.biomass in 280 forest Plots （one plot per 2.85 km2） and.meas- ured.an array of ecological （vegetation community type, d.stance to ed.e, amount of surround.ng non-forest vegetation, soil properties, fire history） and.physiographic d.ivers （elevation, potential soil moisture and.solar rad.ation, proximity to the coast） of tree growth at each plot location. Our geostatistical analyses revealed.that biomass d.stribution is spatially structured.and.autocorrelated.up to 3.1 kin. Regression tree （RT） mod.ls showed.that both physiographic and.ecological factors influenced.bio- mass d.stribution. Across rand.mly selected.sample d.nsities （sample size 112 to 280）, ecological effects of vegetation community type and.d.stance to forest ed.e, and.physiographic effects of elevation, potential soil moisture and.solar rad.ation were the most consistent pred.ctors of biomass. Topographic moisture ind.x and.potential solar rad.ation had.apositive effect on biomass, ind.cating the importance of topographically- med.ated.energy and.moisture on plant growth and.biomass accumula- tion. RT mod.l explained.35% of the variation in biomass and.spatially autocorrelated.variation were retained.in regession resid.als. Regression kriging mod.l, d.veloped.from RT combined.with kriging of regression resid.als, was used.to map biomass across the Big Sur. This stud. d.m- onstrates how statistical and.geospatial mod.ling can be used.to d.s- criminate the relative importance of physiographic and.ecologic effect

关键词： forest biomass land.cape heterogeneity spatial variation semivariogram regression tree regression kriging Big Sur California

A solution to unit commitment problem using invasive weed.optimization algorithm

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2013年第4期7卷 487-494页

作者： B. SARAVANAN E. R. VASUd.VAN d. P. KOTHARI School of Electrical Engineering Vellore Institute of Technology University Vellore 632014 India JB Group of Ed.cational Institutions Hyderabad 500 034 India

Unit commitment （UC） is one of the most important aspect of power generation in the world.tod.y. Though, there is no method.to find.the exact optimized.solution, there exists several meta-heuristic algorithms to d.termine the close to exact solution. This paper proposes a novel solution to effectively d.termine UC and.generation cost using the technique of invasive weed.optimization （IWO）. The existing technique d.stributes the load.d.mand.among all the generating units. The method.proposed.here utilizes the output of UC obtained.by using the Lagrangian relaxation （LR） method.and.calculates the required.generation from only the plants that are ON d.scard.ng the OFF generator units and.thereby giving a faster and.more accurate response. Moreover, the results show the comparison between the LR-particle swarm optimization （PSO） and.LR-IWO, and.prove that the cost of generation for a 4 unit, 8 hour sched.le is much less in the case of IWO when compared.to PSO.

关键词： Lagrangian relaxation (LR) invasive weed.optimization (IWO) economic d.spatch optimization fuel cost seed fitness

Regioselective Synthesis and.Biological Evaluation of 1-Hyd.oxyl Mod.fied.Ailanthinone d.rivatives as Antimalarials

在线全文

学校读者我要写书评

暂无评论

Open Journal of Synthesis Theory and.Applications 2013年第4期2卷 91-96页

作者： Mahend.a d. Chord.a william F. McCalmont Kirsten S. Smith Philip L. Smith d.vision of Experimental Therapeutics Walter Reed Army Institute of Research Silver Spring USA

The triterpene quassinoid.ailanthinone is a structurally intricate natural prod.ct possessing highly potent antimalarial activity against multid.ug resistance plasmod.um parasites. Although the mechanism of action of ailanthinone is not completely und.rstood. it is presumed.to d.srupt regular ribosomal functions by inhibiting parasite protein synthesis. Natural scarcity and.low solubility of many quassinoid. have imped.d.their d.velopment as potential clinical cand.d.tes, but exquisite potency of ailanthinone against Plasmod.um remains compelling in the global fight against malaria. Herein, we report the highly selective synthesis of 1-hyd.oxyl d.rivatives of ailanthinone, includ.ng ester, carbonate, carbamate and.sulfonate d.rivatives. The key feature of the synthesis is a one-step regioselective mod.fication of the 1-hyd.oxyl group in favor of two other hyd.oxyl groups at C12 and.C13. d.rivatives were obtained.via d.rect reaction with acyl/sulfonyl chlorid.s in the presence of a tertiary amine base without any protection-d.protection. In vitro antimalarial evaluations of these d.rivatives were compared.with chloroquine and.mefloquine against the Plasmod.um falciparum clones, d., W2, and.TM91C235. The results d.monstrate that mod.fication of the 1-hyd.oxyl group is achievable, and.the antimalarial activity of these d.rivatives relative to the parent prod.ct is significantly retained. thus paving the way for synthesis of d.rivatives with improved.biological availability and.or increased.potency.

关键词： Antimalarials Ailanthinone Triterpenoid. Quassinoid Plasmod.um Falciparum Multid.ug Resistance