检索结果-南通市图书馆

JUSTIFICATION OF A TWO-DIMENSIONAL NONLINEAR SHELL MODEL OF KOITER'S TYPE

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2001年第2期22卷 129-144页

作者： P. G. CIARLet A. ROQUEFORT Laboratoire d'Analyse Numérique Université Pierre et Marie Curie 4 Place Jussieu 75005 Paris France

A two-dimensional nonlinear shell model "of Koiter’s type" has recently been proposed by the first author. It is shown here that, according to two mutually exclusive sets of assumptions bearing on the associated manifold of admissible inextensional displacements, the leading term of a formal asymptotic expansion of the solution of this two-dimensional model, with the thickness as the "small’ parameter, satisfies either the two-dimensional equations of a nonlinearly elastic "membrane" shell or those of a nonlinearly elastic "flexural" shell. These conclusions being identical to those recently drawn by B. Miara, then by V. Lods and B. Miara, for the leading term of a formal asymptotic expansion of the solution of the equations of three-dimensional nonlinear elasticity, again with the thickness as the "small" parameter, the nonlinear shell model of Koiter’s type considered here is thus justified, at least formally.

关键词： Shell model Koiter's type Justfication

Hyperbolicity of unitary involutions

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2012年第5期55卷 937-945页

作者： KARPENKO Nikita A. Institut de Math'ematiques de Jussieu Universit'e Pierre et Marie CurieParisFrance

We prove the so-called Unitary Hyperbolicity Theorem,a result on hyperbolicity of unitary *** analogous previously known results for the orthogonal and symplectic involutions are formal consequences of the unitary *** the original proofs in the orthogonal and symplectic cases were based on the incompressibility of generalized Severi-Brauer varieties,the proof in the unitary case is based on the incompressibility of their Weil transfers.

关键词： algebraic groups involutions projective homogeneous varieties Chow groups and motives Steenrod operations

An innovative cartographic concept——The Geodynamic Map of the Mediterranean

在线全文

学校读者我要写书评

暂无评论

Episodes 2005年第3期28卷 193-196页

作者： Barrier, Eric Chamot-Rooke, Nicolas Giordano, Guido Morelli, Andrea Brouillet, Jean-Çois universite pierre and marie curie Paris France Ecole Normale Superieure Paris France Universita di Roma TRE Roma Italy Istituto Naziolale di Geo.sica e Vulcanologia Roma Italy CNRS Universite Pierre and Marie Curie Paris France

Rationale of the map The collision between Eurasia and Africa-Arabia started in Paleogene times and is still active today. The recent geodynamics of the Arabo-Mediterranean domain are dominated by the progressive closure of remnant oceanic basins squeezed between the Eurasian margin and the Nubia （Africa） and Arabia plates. Various stages of consumption have been reached from Gibraltar to Oman, ranging from incipient inversion （e.g. the North African margin）, to subduction （Mesozoic basins of the Eastern Mediterranean） and collision （e.g. the Zagros or Caucasus belts）. Convergence is accompanied by deformation of both Eurasian and African margins, mostly as diffuse compression, but also as extension in short-lived basins and motion of blocks escaping towards the remnant oceanic spaces. The resulting kinematic pattern is quite complex. Western Mediterranean domain is merely accommodating the slow convergence of Nubia, whereas the still high convergence of Arabia in the Eastern domain has pushed Anatolia sideways, which is now laterally escaping to the west-southwest.

关键词：地中海海洋地质《地中海地球动力学图》地质条件

Survival Model Inference Using Functions of Brownian Motion

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 Mathematics 2012年第6期3卷 641-651页

作者： John O’Quigley universite pierre et marie curie Paris France

A family of tests for the presence of regression effect under proportional and non-proportional hazards models is described. The non-proportional hazards model, although not completely general, is very broad and includes a large number of possibilities. In the absence of restrictions, the regression coefficient, β(t), can be any real function of time. When β(t) = β, we recover the proportional hazards model which can then be taken as a special case of a non-proportional hazards model. We study tests of the null hypothesis;H0:β(t) = 0 for all t against alternatives such as;H1:∫β(t)dF(t) ≠ 0 or H1:β(t) ≠ 0 for some t. In contrast to now classical approaches based on partial likelihood and martingale theory, the development here is based on Brownian motion, Donsker’s theorem and theorems from O’Quigley [1] and Xu and O’Quigley [2]. The usual partial likelihood score test arises as a special case. Large sample theory follows without special arguments, such as the martingale central limit theorem, and is relatively straightforward.

关键词： Brownian Motion Brownian Bridge Cox Model Integrated Brownian Motion Kaplan-Meier Estimate Non-Proportional Hazards Reflected Brownian Motion Time-Varying Effects Weighted Score Equation

Acetic acid additive in NaNO_(3)aqueous electrolyte for long-lifespan Mg-air batteries

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 Magnesium and Alloys 2024年第2期12卷 825-839页

作者： Yaqing Zhou Fan Sun Gunahua Lin Sandrine Zanna Antoine Seyeux Philippe Marcus Jolanta´Swiatowska Chimie ParisTech-CNRS PSL UniversityInstitut de Recherche de Chimie Paris11 rue Pierre et Marie CurieParis 75005France

Mg-air batteries have attracted tremendous attention as a potential next-generation power source for portable electronics and e-transportation due to their remarkable high theoretical volumetric energy density,environmental sustainability,and ***,the fast hydrogen evolution reaction(HER)in NaCl-based aqueous electrolytes impairs the performance of Mg-air batteries and leads to poor specific capacity,low energy density,and low ***,the conventionally used NaCl solute was proposed to be replaced by NaNO_(3)and acetic acid additive as a corrosion inhibitor,therefore an electrolyte engineering for long-life time Mg-air batteries is *** resulting Mg-air batteries based on this optimized electrolyte demonstrate an improved discharge voltage reaching~1.8 V for initial 5 h at a current density of 0.5 mA/cm^(2) and significantly prolonged cells'operational lifetime to over 360 h,in contrast to only~17 h observed in NaCl electrolyte.X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were employed to analyse the composition of surface film and scanning electron microscopy combined with transmission electron microscopy to clarify the morphology changes of the surface layer as a function of acetic acid *** thorough studies of chemical composition and morphology of corrosion products have allowed us to elucidate the working mechanism of Mg anode in this optimized electrolyte for Mg-air batteries.

关键词： Acetic acid additive in NaNO_(3)electrolyte Electrolyte engineering Corrosion surface film Surface characterization Hydrogen evolution

Synthesis of 3″-and 4″-deoxy-Lewis^x trisaccharides:A useful tool for study of carbohydrate-carbohydrate interaction

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2010年第9期53卷 1963-1969页

作者： GOURMALA Chafika Université pierre et marie curie-Paris 6 Institut Parisien de Chimie Moléculaire

Synthesis of 3″-deoxy and 4″-deoxy Lewisx trisaccharides is *** 2,3,6-tri-O-benzoyl-4-deoxy-1-thio-β-Dxylo-hexopyranoside was condensed with a diol of glucosamine to give regio-and stereo-selectively a ***-lective fucosylation of this disaccharide provided a protected deoxy Lewisx trisaccharide which was deprotected to give the 4″-deoxy Lewisx *** of the similar synthetic sequence provided the 3″-deoxy Lewisx trisaccharide.

关键词： carbohydrate glycosylation synthesis trisaccharide.

ELECTROCHEMICAL REDUCTION OF TANTALUM IN MOLTEN NaCl KCl-K_(2)TaF_(7)

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 1992年第3期2卷 64-68页

作者： Li Guoxun Barhoun A. Lantelme F. Chemla M. General Research Institute for Nonferrous Metals Beijing 100088China universite pierre et marie curie ParisFrance

The cathode process of tantalum ion in molten NaCl-KCl-K_(2)TaF_(7),at 720℃was investigated by three transient electrochemical *** results show that the electroreduction reaction of Ta5*involves a single reversible five electron *** diffusion coefficients of the complexion containing Tas*measured by above mentioned techniques are alike such as 1.15×10^(-5)by cyclic voltammetry.1.10×10^(-5)by chronopotentiometry and 1.15×10^(-5)by chronoamperometry *** effect of electroactive species containing oxygen on tantalum reduction process was also studied.

关键词： electrochemical reduction tantalum molten NaCl-KCl-K_(2)TaF_(1)

Morphological structure and optical properties of the wings of Morphidae

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Insect Science 2006年第2期13卷 145-158页

作者： SERGE BERTHIER ERIC CHARRON JULIE BOULENGUEZ Institut des Nanosciences de Pads UMR CNRS-Universite Pierre et Made Curie Pads France

The morphological structure and optical properties of the wings of 14 species of Morphidae have been investigated. Most of the scales of the iridescent species of Morphidae （Lepidoptera） present a very particular structure. The ground scales, responsible for the major part of the optical properties, are covered by a very regular set of longitudinal ridges. The ridges themselves are constituted by a superposition of lamellae that act locally as a multilayered structure. This very specific morphology leads to both interferences and diffraction effects. The first one is responsible of the brilliant blue coloration of the males, while the second one diffracts this colored light at a very large angle. These two phenomena give to the butterfly a very effective long-range communication system. The morphological characteristics of the scales of the various species are presented in detail. Two types of optical measurement were performed on the iridescent wings of 14 different species of Morphidae： spectroscopic measurements under various incidences and gonioscopic measurements for a given incidence angle and wavelength. The first allows a determination of the index of refraction of the cuticular material. The second leads to the drawing of spatial diffraction maps. It shows that most of the reflected light is diffracted laterally over a very large angle （90° 〈 0 〈 120°, according to the different species） and that this repartition depends of the polarization of incident light. As predicted by previous calculations, the dissymmetric structure of the ridge is responsible for the separation of the polarization modes in the various diffraction orders.

关键词： Iridescence morphidae optical properties photonic cristals physical colors,scales structures

CO_2,carbonate-rich melts,and brines in the mantle

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2014年第5期5卷 697-710页

作者： Maria-Luce Frezzotti Jacques L.R.Touret Department of Earth and Environmental Sciences University Milano Bicocca.P.za Della Scienza 4.20126 Milano.Italy Mineralogy Universite Pierre et Marie Curie4 Place Jussieu 75272 Paris Cedex 05France

This paper reviews the origin and evolution of fluid inclusions in ultramaflc xenoliths, providing a framework for interpreting the chemistry of mantle fluids in the different geodynamic settings. Fluid inclusion data show that in the shallow mantle, at depths below about 100 km, the dominant fluid phase is CO2 ± brines, changing to alkali-, carbonate-rich （silicate） melts at higher pressures. Major solutes in aqueous fluids are chlorides, silica and alkalis （saline brines; 5-50 wt.% NaCl eq.）. Fluid inclusions in peridotites record CO2 fluxing from reacting metasomatic carbonate-rich melts at high pressures, and suggest significant upper-mantle carbon outgassing over time. Mantle-derived CO2 （±brines） may eventually reach upper-crustal levels, including the atmosphere, independently from, and additionally to magma degassing in active volcanoes.

关键词： Fluid inclusionPeridotiteMantle metasomatismCarbonate-rich meltCO2Saline brine