检索结果-南通市图书馆

Molecular Frame Photoemission： Probe of the Photoionization Dynamics for Molecules in the Gas Phase

chinese journal of chemical Physics 2009年第2期22卷 178-186页

作者： D. Dowek Y. j. Picard P. Billaud c. Elkharrat j. c. Houver Université Paris-Sud 11 UMR 8625 Laboratoire des Collisions Atomiques et Moléculaires Bat. 351 Université Paris-Sud 91405 Orsay France cNRS UMR 8625 Laboratoire des Collisions Atomiques et Moléculaires Bat. 351 Université Paris-5ud 91405 Orsay France

Molecular frame photoemission is a very sensitive probe of the photoionization （PI） dynamics of molecules. This paper reports a comparative study of non-resonant and resonant photoionization of D2 induced by VUV circularly polarized synchrotron radiation at SOLEIL at the level of the molecular frame photoelectron angular distributions （MFPADs）. We use the vector correlation method which combines imaging and time-of-flight resolved electron-ion coincidence techniques, and a generalized formalism for the expression of the Ⅰ（χ, θe, Фe） MFPADs, where χ is the orientation of the molecular axis with respect to the light quantization axis and （θe, Фe） the electron emission direction in the molecular frame. Selected MFPADs for a molecule aligned parallel or perpendicular to linearly polarized light, or perpendicular to the propagation axis of circularly polarized light, are presented for dissociative photoionization （DPI） of D2 at two photon excitation energies, hv=19 eV, where direct PI is the only channel opened, and hv=32.5 eV, i.e. in the region involving resonant excitation of Q1 and Q2 doubly excited state series. We discuss in particular the properties of the circular dichroism characterizing photoemission in the molecular frame for direct and resonant PI. In the latter case, a remarkable behavior is observed which may be attributed to the interference occurring between undistinguishable autoionization decay channels.

关键词： Dissociative photoionization Molecular frame photoemission circular dichroism in photoemission Autoionization dynamics Synchrotron radiation Vector correlation

来源：

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

Strategies towards robust interpretations of in situ zircon Lu-Hf isotope analyses

引用

Geoscience Frontiers 2020年第3期11卷 843-853页

作者： c.j.Spencer c.L.Kirkland N.M.W.Roberts N.j.Evans j.Liebmann School of Earth and Planetary Sciences The Institute for Geoscience Research(TIGeR)Curtin UniversityPerthAustralia Department of Geological Sciences and Geological Engineering Queen’s UniversityKingstonCanada centre for Exploration Targeting-curtin Node The Institute for Geoscience ResearchSchool of Earth and Planetary SciencesCurtin UniversityPerthAustrali Geochronology and Tracers Facility British Geological SurveyNottinghamUK john de Laeter centre GeoHistory Facility School of Earth and Planetary SciencesCurtin UniversityPerthAustralia

The combination of U-Pb and Lu-Hf compositions measured in zircon crystals is a remarkably powerful isotopic couplet that provides measures on both the timing of mineral growth and the radiogenic enrichment of the source from which the zircon *** U-Pb age documents the timing of zircon crystallization/recrystallization and Hf isotopes inform on the degree to which the host melt was derived from a radiogenic reservoir(*** mantle) versus an unradiogenic reservoir(*** continental crust),or some mixture of these *** ease of generating large quantities of zircon U-Pb and Lu-Hf data has been in large part facilitated by instrument ***,the dramatic increase in time constrained zircon Lu-Hf analyses in the Earth science community has brought to the fore the importance of careful data collection and reduction workflows,onto which robust geological interpretations may be *** this work,we discuss the fundamentals of Lu-Hf isotopes in zircon,which then allows us to provide a robust,accessible,methodology for the assessment of data ***,we discuss some novel techniques for:data visualization—that facilitates better transparency of data interpretation;integration of geographic information—that may reveal spatial trends where temporal trends were only apparent before;and some novel statistical evaluation tools—that may provide more rigorous interand intra-sample comparisons.

关键词： Zircon Geochronology Isotope geochemistry Lu-Hf isotopes Geostatistics Data visualization

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Responses of Iron-Reducing Bacteria to Salinity and Organic Matter Amendment in Paddy Soils of Thailand

引用

Pedosphere 2012年第3期22卷 375-393页

作者： A.j.BONGOUA-DEVISME c.MUSTIN j.BERTHELIN Laboratory of Microorganism-Mineral-Organic Matter interactions in Soil (LIMOS) Nancy-UniversityB.P.7023954506 Vandoeuvre-les-Nancy (France) National center of Scientific Research (cNRS)-Laboratory of Microorganism-Mineral-Organic Matter Interactions in Soil (LIMOS) UMR 7137CNRSNancy-UniversityB.P.7023954506 Vandoeuvre-les-Nancy (France)

In paddy soils of Thailand, the addition of organic matter （OM） is used to efficiently limit the effect of salinity on rice culture and production. OM used as an amendment and fertilizer promotes the reduced condition and increases iron solubilization without provoking ferrous toxicity. In this study, the intricate biogeochemical role of iron-reducing bacteria （IRB） involved in the quality of water and soil of paddy fields, particularly when the paddy fields were subject to salinity and organic matter addition, were studied in paddy fields of Thailand. The results demonstrated that the addition of OM increased the proliferation of cultivable IRB and their specific activity. cultivable IRB communities decreased in the presence of salt. The presence of salt modified the structure of the bacterial populations by favoring the development of alkaline and moderately halophilic bacteria （Virgibacillus spp., Occanobacillus spp., and PaenibaciUus spp.）. The paddy soils studied contained very diversified （halosensitive, halotolerant, and halophilic） IRB populations that could be adapted to a variety of salinity conditions （0-90 g L-1 NacI） using different organic substrates （glucose, acetate, and soil organic matter） to maintain significant activities under extreme conditions of salinity. The rhizosphere of rice stimulated IRB community growth without organic matter, whereas organic matter addition limited the rhizosphere effect on IRB cultivable number in saline condition. The interactive action of salinity and organic amendment had a negative impact on the rhizosphere effect. The presence of specific iron-reducing populations （fermentative, iron-respiring, anaerobic, and facultative anaerobic）, having different behaviors under salt and redox stresses, appeared to be a key factor that contributed to the control or enhancement of the quality of water and soil in paddy fields.

关键词： bacterial communities bacterial populations organic substrates paddy fields rhizosphere

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Measuring the condition of Saline Wetlands Threatened by Agricultural Intensification

引用

Pedosphere 2008年第1期18卷 11-23页

作者： c.cASTAEDA j.HERRERO j.HERRERO Soils and Irrigation Department Agri-Research Center of AragonPO Box 72750080 Zaragoza (Spain)

The saline wetlands,or'saladas',of Monegros Desert,NE Spain,contain biodiversity that depends on the estab- lishment of a prognostic monitoring system that can warn of approaching irreversible *** the context of a lack of existing biodiversity inventories for the saladas,we determined their state of conservation and vulnerability using seven physical indicators:escarpment continuity,cropping,stone dumping,size,water occurrence,distance to roads,and proximity to irrigated *** features were combined into three meaningful indexes,i.e.,conservation,current vulnerability,and future vulnerability,thus creating an assessment of the preservation or degradation of saladas in the context of encroaching agricultural irrigation *** proposed indexes produced consistent results and showed that a great number of the Monegros wetlands were threatened,regardless of their size or frequency of water *** 20% of the saladas studied were classified as being in a good or very good conservation,whereas 50% were in bad or very bad shape.A high current vulnerability was found for 60% of the *** saladas located in land to be irrigated, we predicted that 73% would have a high or very high future ***,58% of the saladas were in bad or very bad condition and fully 65% of the saladas,variable in size,presented a bad or very bad *** approach provides a monitoring strategy for the conservation of saline wetlands threatened by agricultural intensification,especially irrigation.

关键词： agricultural landscape desert irrigation Monegros playa

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Mixed convection flow in vertical channel with boundary conditions of third kind in presence of heat source/sink

引用

Applied Mathematics and Mechanics(English Edition) 2012年第8期33卷 1015-1034页

作者： j.c.UMAVATHI j.PRATHAP KUMAR jAWERIYA SULTANA Department of Mathematics Gulbarga UniversityGulbarga 585106KarnatakaIndia

The effects of viscous dissipation and heat source/sink on fully developed mixed convection for the laminar flow in a parallel-plate vertical channel are investigated. The plate exchanges heat with an external fluid. Both conditions of equal and different reference temperatures of the external fluid are considered. First, the simple cases of the negligible Brinkman number or the negligible Grashof number are solved analytically. Then, the combined effects of buoyancy forces and viscous dissipation in the presence of heat source/sink are analyzed by a perturbation series method valid for small values of the perturbation parameter. To relax the conditions on the perturbation parameter, the velocity and temperature fields are solved by using the Runge-Kutta fourth-order method with the shooting technique. The velocity, temperature, skin friction, and Nusselt num- bers at the plates are discussed numerically and presented through graphs.

关键词： mixed convection viscous fluid perturbation method Runge-Kuttashooting method heat source/sink

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Strategies for practitioners to support patients in plant-based eating

引用

journal of Geriatric cardiology 2017年第5期14卷 338-341页

作者： Micaela c Karlsen Kathryn j Pollard Nutritional Epidemiology Program Tufts Friedman School of Nutrition Science and Policy Boston Massachusetts USA T. colin campbell center for Nutrition Studies Ithaca NY 14851 USA

Successfully implementing a plant-based diet is attain-able for patients, but the likelihood of achieving long-term,dietary maintenance can be increased by follow-up andsupport from practitioners. Practitioners, in particular physi-cians, are seen as nutrition authorities,and are thereforewell-positioned to deliver dietary advice and nutritionalprescriptions.

关键词： Adherence Behavior change Dietary change Motivational interviewing Plant-based diet Vegetarian

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

River Water Quality Assessment in Selected Yangtze Tributaries: Background and Method Development

引用

journal of Earth Science 2010年第6期21卷 876-881页

作者： Sonja c jhnig 蔡庆华 Department of Limnology and conservation Senckenberg Research Institute and Natural History Museum Gelnhausen Germany Biodiversity and climate Research centre (BiK-F) State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology Chinese Academy of Sciences

Water pollution is among the most severe environmental problems in china, particularly in the vicinity of residential and urban areas. In almost all Asian countries, river monitoring is predominantly based on the analysis of chemical data. However, biological data are a worthwhile addition for the determination of the long-term ecological status of rivers and are particularly well-suited in case of steep pollution and disturbance gradients. A tool for river water quality assessment using benthic invertebrates has been developed for selected tributaries of the middle reach of the Yangtze River. Site selection was supported by a preclassification considering physico-chemical and hydromorphological conditions. Following a stratified sampling design, 34 samples were taken in small and large streams in the subtropical mountainous area of western Hubei （湖北）（china） covering a pollution gradient, accompanied by an extensive field protocol on stream characteristics and （physico-） chemical water analyses. The proposed assessment system is computed as an average score per taxon. The challenge to further consider the additional impact from global change into the development of such tools is discussed.

关键词： benthic invertebrate biological assessment ecological quality organic pollution Hubei climate change.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Extraction of Nuclear Matter Properties from Nuclear Masses by a Model of Equation of State

引用

communications in Theoretical Physics 2001年第11期36卷 583-588页

作者： K.c.chung c.S.Wang A.j.Santiago Instituto de Fisica Universidade do Estado do Rio de JaneiroRio de Janeiro-RJ 20559-900Brazil Instituto de FisicaUniversidade do Estado do Rio de JaneiroRio de Janeiro-RJ 20559-900Brazil Instituto de FisicaUniversidade do Estado do Rio de JaneiroRio de Janeiro-RJ 20559-900Brazil

The extraction of nuclear matter properties from measured nuclear masses is investigated in the energy density functional formalism of *** is shown that the volume energy a1 and the nuclear incompressibility Ko depend essentially on μnN -+- pZ - 2EN,whereas the symmetry energy j and the density symmetry coefficient L as well as symmetry incompressibility Ks depend essentially on μn - μp,where μp ＝μp - Ec/ Z,μn and μp are the neutron and proton chemical potentials respectively,EN the nuclear energy,and Ec the coulomb *** obtained symmetry energy is j ＝ 28.5 MeV,while other coefficients are uncertain within ranges depending on the model of nuclear equation of state.

关键词： nuclear matter properties,nuclear matter equation of state

来源：

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

c_c(X)Spaces with X Locally compact

引用

Acta Mathematica Sinica,English Series 2007年第9期23卷 1593-1600页

作者： j.c.FERRANDO S.MOLL centro de Investigación Operativa Universidad Miquel Hernández Departamento de Matemática Aplicada Universidad Politécnica

In this paper, we show, among other results, that if X is a [separable] locally compact space X [satisfying the first countability axiom] then the space cc （X） has countable tightness [if and only if it has bounding tightness] if and only if it is Frechet-Urysohn, if and only if cc （X） contains a dense （LM） subspace and if and only if X is a-compact.

关键词： Frechet-Urysohn space countable [bounding] tightness (LM)-space

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

OPTIMAL AND PRESSURE-INDEPENDENT L2 VELOcITY ERROR ESTIMATES FOR A MODIFIED cROUZEIX-RAVIART STOKES ELEMENT WITH BDM REcONSTRUcTIONS

引用

journal of computational Mathematics 2015年第2期33卷 191-208页

作者： c. Brennecke A. Linke c. Merdon j. Schoberl Eidgen6ssische Technische Hochschule Ziirich Departement Mathematik Riimistr. 101 8092 Ziirich Switzerland Weierstrass Institute for Applied Analysis and Stochastics Mohrenstr. 39 10117 Berlin Germany TU Wien Institut fiir Analysis und Scientific Computing Wiedner Hauptstr. 8-10//1011040 Wien Austria

Nearly all inf-sup stable mixed finite elements for the incompressible Stokes equations relax the divergence constraint. The price to pay is that a priori estimates for the ve- locity error become pressure-dependent, while divergence-free mixed finite elements de- liver pressure-independent estimates. A recently introduced new variational crime using lowest-order Raviart-Thomas velocity reconstructions delivers a much more robust modi- fied crouzeix-Raviart element, obeying an optimal pressure-independent discrete H1 ve- locity estimate. Refining this approach, a more sophisticated variational crime employing the lowest-order BDM element is proposed, which also allows proving an optimal pressure- independent L2 velocity error. Numerical examples confirm the analysis and demonstrate the improved robustness in the Navier-Stokes case.

关键词： Variational crime crouzeix-Raviart finite element Divergence-free mixed me-thod Incompressible Navier-Stokes equations A priori error estimates.

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：