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Eigenchannel Theory and R-Matrix Theory

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Chinese Physics Letters 1996年第12期13卷 902-905页

作者： LI Jia-ming VO Ky-lan YAN Jun QU Yi-zhi Institute of Physics Chinese Academy of SciencesBeijing 100080 observatoire de nice URA 1362 du CNRSBP 22906304 Nice CedexFrance

We here combine the eigenchannel theory and R-matrix theory to calculate the eigenchannel parameters of multichannel quantum defect theory *** are two advantages:(1)an analytical unified treatment of perturbed discrete Rydberg states,autoionizing states and their adjacent continuum to avoid numerical calculations,outside the R-matrix box;(2)clear assignment of overlapped resonances.

关键词： states matrix unified

The astrophysical gravitational wave stochastic background

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Research in Astronomy and Astrophysics 2011年第4期11卷 369-390页

作者： Tania Regimbau UMR ARTEMIS CNRS University of nice Sophia-Antipolis Observatoire de la Cte d'AzurBP 422906304Nice Cedex 4France

A stochastic background of gravitational waves with astrophysical origins may have＇resulted from the superposition of a large number of unresolved sources since the beginning of stellar activity. Its detection would put very strong constraints on the physical properties of compact objects, the initial mass function and star for- marion history. On the other hand, it could be a ＇noise＇ that would mask the stochastic background of its cosmological origin. We review the main astrophysical processes which are able to produce a stochastic background and discuss how they may differ from the primordial contribution in terms of statistical properties. Current detection methods are also presented.

关键词： gravitational waves -- stochastic background: neutron stars -- blackholes

Optical turbulence profiling with single star SCIDAR technique

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Chinese Science Bulletin 2013年第36期58卷 4566-4570页

作者： LIU LiYong YAO YongQiang VERNIN Jean WANG HongShuai CHADID Merieme WANG YiPing GIORDANO Christophe YIN Jia QIAN Xuan National Astronomical Observatories Chinese Academy of Sciences Universite' de nice-Sophia Antipolis Observatoire de la Co te d’Azur CNRS-UMR7293 Lab. Lagrange 06108 Nice Cedex 2 France

In order to characterize optical turbulence,we have developed a single star SCIDAR(SSS)for measurement of the distribution of C2n with *** SSS consists of a 40 cm telescope and a CCD camera for fast sampling of stellar scintillation *** auto and cross-correlation functions of the single star images are computed,providing vertical profiles of optical turbulence intensity C2n(h)and wind speed V(h).Using this new SSS experiment,profiles of turbulence can be obtained from the ground to the top of atmosphere,allowing the determination of seeing,isoplanatic angle and coherence *** characteristics of atmospheric optical turbulence are important for active and passive imaging,astronomical site testing,adaptive optics,laser communications,target tracking and designation,and laser beam *** plan to improve the robotization of the SSS to be able to use it routinely even under harsh weather and altitude conditions that we expect to encounter on the high Tibetan plateau or at Dome A in *** will also be applied for the site testing campaign of the future Chinese extremely large telescope.

关键词：大气光学湍流 AR技术 SCID CCD相机自适应光学激光束控制 SSS 高度分布

Gravitational waves from compact objects

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Research in Astronomy and Astrophysics 2010年第11期10卷 1071-1099页

作者： José Antonio de Freitas Pacheco University of nice-Sophia Antipolis Observatoire de la Cote d'Azur Laboratoire Cassiopée-UMR 6202 BP 4229-F606304-Nice Cedex 4-France

Large ground-based laser beam interferometers are presently in operation both in the USA （LIGO） and in Europe （VIRGO） and potential sources that might be detected by these instruments are revisited. The present generation of detectors does not have a sensitivity high enough to probe a significant volume of the universe and, consequently, predicted event rates are very low. The planned advanced generation of interferometers will probably be able to detect, for the first time, a gravitational sig- nal. Advanced LIGO and EGO instruments are expected to detect few （some）： binary coalescences consisting of either two neutron stars, two black holes or a neutron star and a black hole. In space, the sensitivity of the planned LISA spacecraft constellation will allow the detection of the gravitational signals, even within a ＂pessimistic＂ range of possible signals, produced during the capture of compact objects by supermassive black holes, at a rate of a few tens per year.

关键词： gravitational waves -- neutron stars -- black holes

Generalized flyby trajectories around elongated minor celestial bodies as a rotating mass dipole

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Acta Mechanica Sinica 2016年第3期32卷 535-545页

作者： Xiangyuan Zeng Baodong Fang Junfeng Li Yang Yu School of Aerospace Engineering Tsinghua UniversityBeijing 100084 China Shanghai Satellite Engineering Research Institute Shanghai 200240 China observatoire de la Cote d'Azur 06300 Nice France

The aim of this paper is to understand the common characteristics of the generalized flyby trajectory around natural elongated bodies. Such flyby trajectories provide a short-term mechanism to clear away vicinal objects or temporally capture ejecta into circling orbits. The gravitational potential of elongated bodies is described by a unified approximate model, i.e., the rotating mass dipole which is two point masses connected with a constant massless rod The energy power is used to illustrate the flyby effect in terms of the instantaneous orbital energy. The essential of the single flyby trajectory is studied analytically, and the relationship between the flyby trajectory and its Jacobi integral is also illustrated. Sample trajectories are given to show the variational trend of the energy increment with respect to differen orbital periapsides. The distribution of natural ejecting orbits is presented by varying the parameters of the approximate model.

关键词： Generalized flyby trajectory Natural elongated body Rotating mass dipole Natural ejecting orbits

Shapes,structures,and evolution of small bodies

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Astrodynamics 2021年第4期5卷 293-329页

作者： Yun Zhang Patrick Michel Universit´e Cote d’Azur Observatoire de la Cote d’AzurCNRSLaboratoire LagrangeNice06304France department of Aerospace Engineering University of MarylandCollege ParkMD20742USA

Small bodies are among the best tracers of our Solar System’s history.A large number of space missions to small bodies(past and future)offer a unique opportunity to use these bodies as a natural laboratory to study the different processes,mechanical structures,and responses that drive the origin and evolution of small bodies,which are connected to the origin,evolution,and current architecture of the Solar *** of small bodies sent by spacecraft have revealed unexpectedly rich and complex geological *** addition to very diverse compositions,small bodies in the Solar System have highly diverse shapes and structures,which reflect both different evolutionary paths and material ***,each individual body has diverse geological features on its surface,which include craters of various sizes and depths,boulders of different sizes and morphologies,lineaments,fractures,pits,signatures of landslides,terraces,and *** a geological richness could not be detected via ground-based observations,and we are still at the beginning of understanding their significance on the low-gravity surfaces on which they *** combination of space mission data and numerical modeling allows us to enrich our understanding of the origin,evolution,and physical properties of these fascinating *** instance,starting from the shape models,bulk densities,and spin rates determined from space mission data,we can investigate the formation mechanisms that lead to the observed properties of small *** can also infer the interior and mechanical properties(e.g.,friction and cohesion)that allow a small body to be structurally stable,as well as its further potential evolution under processes such as a spin rate increase or an ***,considering the various processes that these bodies experience during their evolution,we can investigate how these processes modify their properties and,in turn,how those properties influence the outcome of these ***

关键词： small bodies internal structure collisional evolution thermal evolution rotational evolution tidal encounter

ON THE KOLMOGOROV ENTROPY OF TWO-DIMENSIONAL AREAPRESERVING MAPPINGS

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Science China Mathematics 1982年第7期 750-758页

作者：孙义燧,C.FROESCHLE department of Astronomy Nanjing University observatoire de nice France

We investigate the Kolmogorov entropy of a peculiar family of area-preserving mappingsfor which the magnitude a of the nonlinear perturbation and the number n of its Fouriercomponents are varied. For large n|a|, the n... 详细信息

关键词： ON THE KOLMOGOROV ENTROPY OF TWO-DIMENSIONAL AREAPRESERVING MAPPINGS

Structural analysis of rubble-pile asteroids applied to collisional evolution

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Astrodynamics 2017年第1期1卷 57-69页

作者： Yang Yu derek CRichardson Patrick Michel School of Aeronautic Science and Technology Beihang UniversityBeijing 100191China department of Astronomy University of MarylandCollege Park MD 20740-2421USA observatoire de la Cote d'Azur UMR 7293 Lagrange/CNRS06304 Nice Cedex 4France

Solar system small bodies come in a wide variety of shapes and sizes,which are achieved following very individual evolutional paths through billions of ***,some common mechanisms can still be found during these processes,e.g.,rubble-pile asteroids tend towards fluid equilibrium as they are reshaped by external *** paper focuses on the reshaping process of rubble-pile asteroids driven by meteorite impacts.A mesoscale cluster of solid spheres is employed as the principal model for a rubble-pile asteroid,for which little is actually known about their interior *** take this simple model as a rough guide to the qualitative aspects of the reshaping processes,and it can reveal,to some degree,the inner workings of rubble-pile *** our study,numerous possible equilibrium configurations are obtained via Monte Carlo simulation,and the structural stability of these configurations is determined via eigen analysis of the geometric *** eigen decomposition reveals a connection between the cluster’s reactions and the types of external *** simulations are performed to verify the analytical *** gravitational N-body code pkdgrav is used to mimic the responses of the cluster under intermittent non-dispersive *** statistically confirm that the stability index I S,the total gravitational potential P G,and the volume of inertia ellipsoid V E show consistent tendency of variation.A common regime is found in which the clusters tend towards crystallization under intermittent impacts,i.e.,only the configurations with high structural stability survive under the external *** results suggest the trivial non-disruptive impacts might play an important role in the rearrangement of the constituent blocks,which may strengthen these rubble piles and help to build a robust structure under impacts of similar *** final part of this study consists of systematic simulations over two parameters

关键词： asteroids interior structure geological processes N-body simulations gravitational aggregates meteorite impacts

The East Anatolia-Lesser Caucasus ophiolite:An exceptional case of large-scale obduction,synthesis of data and numerical modelling

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Geoscience Frontiers 2020年第1期11卷 83-108页

作者： Y.Rolland M.Hässig D.Bosch O.Bruguier R.Melis G.Galoyan G.Topuz L.Sahakyan A.Avagyan M.Sosson Universitéde nice Sophia Antipolis UMR GéoazurCNRSIRDObservatoire de la Côte d’Azur250 Rue Albert Einstein06560Sophia AntipolisFrance EDYTEM Universitéde Savoie e CNRSUMR 5204Le Bourget du LacFrance department of Earth Sciences University of GenevaRue des Maraîchers 131205 GenevaSwitzerland University Montpellier Géosciences MontpellierUMR-CNRS-UM25243Place Eugene Bataillon34095 MontpellierFrance Institute of Geological Sciences National Academy of Sciences24a Baghramyan AvenueYerevan 0019Armenia Istanbul Teknik Universitesi Avrasya Yer Bilimleri Enstitüsü34469 IstanbulTurkey

We present new,geological,metamorphic,geochemical and geochronological data on the East Anatolian-Lesser Caucasus *** data are used in combination with a synthesis of previous data and numerical modelling to unravel the tectonic emplacement of ophiolites in this *** these data allow the reconstruction of a large obducted ophiolite nappe,thrusted for>100 km and up to 250 km on the Anatolian-Armenian *** ophiolite petrology shows three distinct magmatic series,highlighted by new isotopic and trace element data:(1)The main Early Jurassic Tholeiites(ophiolite s.s.)bear LILEenriched,subduction-modified,MORB chemical *** and petrology of the Tholeiite series substantiates a slow-spreading oceanic environment in a time spanning from the Late Triassic to the Middle-Late ***,gabbros and plagiogranites were exhumed by normal faults,and covered by radiolarites,while minor volumes of pillow-lava flows infilled the rift *** towards a subduction-modified geochemical signature suggests emplacement in a marginal basin above a subduction zone.(2)Late Early Cretaceous alkaline lavas conformably emplaced on top of the *** have an OIB *** lavas are featured by large pillow lavas interbedded a carbonate *** show evidence for a large-scale OIB plume activity,which occurred prior to ophiolite obduction.(3)Early-Late Cretaceous calc-alkaline lavas and *** magmatic rocks are found on top of the obducted nappe,above the post-obduction erosion *** series shows similar Sr-Nd isotopic features as the Alkaline series,though having a clear supra-subduction *** are thus interpreted to be the remelting product of a mantle previously contaminated by the OIB *** of data from the Lesser Caucasus to western Anatolia shows a progression from back-arc to arc and fore-arc,which highlight a dissymmetry in the obducted oceanic lithosphere from East to *** metamo

关键词： Ophiolite Obduction Subduction Neotethys