检索结果-南通市图书馆

Optical response and SERS properties of individual large scale supracrystals made of small silver nanocrystals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2015年第5期8卷 1615-1626页

作者： Pierre Aubertin Mohamed Ali Ben Aissa Noureddine Raouafi Suzanne Joiret Alexa Courty Emmanuel Maisonhaute sorbonne universites UPMC Univ Paris 06 UMR 8235 Laboratoire Interfaces et Systemes Electrochimiques F-75005 Paris France CNRS UMR 8235 LISE F-75005 Paris France sorbonne universites UPMC Univ Paris 06 UMR 8233 Laboratoire MONARIS F-75005 Paris France CNRS UMR 8233 Laboratoire MONARIS F-75005 Paris France Laboratoire de Chimie Analytique et Electrochimie Departement de Chimie Faculte des Sciences de Tunis Universite de Tunis El Manar Campus universitaire de Tunis EI-Manar 2092 Tunis El Manar Tunisie

There is a considerable interest in producing and understanding the optical and spectroscopic properties of ordered nanoparticle assemblies. Herein, we describe and interpret the optical absorbance and Raman properties of 5.9 nm ± 0.3 nm diameter silver nanocrystals coated with dodecanethiol and organized in highly ordered 3D superlattices of different heights. Each superlattice was studied individually, which allowed to elaborate a model based on Maxwell-Garnett theory to reproduce qualitatively the height and wavelength dependence of the absorbance. Importantly, because of their small size compared to that of traditional nanoparticles used in Surface Enhanced Raman Spectroscopy （SERS）, the large 3D distribution of hot spots generated by the silver superlattices allowed to easily obtain SERS spectra of the surrounding ligands despite their intrinsic low Raman cross section. Accordingly, traces of thiophenol could be detected very easily.

关键词： nanoparticles nanocrystals superlatfices supracrystals surface enhanced Raman spectroscopy (SERS) plasmonic properties organization

How everything started:A retrospective

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 627-634页

作者： Jacques Touret Institut de Mineralogie.de Physique des Materiaux.et de Cosmochimie IMPMC).sorbonne universites-UPMC Univ Paris 06 UMR CNRS 7590 Museum National d'Histoire Naturelle.IRD UMR 206.4 Place Jussieu F-75005 Paris France

Recalling some of the most important events and persons during his education and career, the author sketches his growth from a young engineer, educated in the sanctuary of solid state reactions, to an involved fully devoted scientific career for the study of fluids in the deep Earth. Most important in this respect was the discovery of C02 inclusions in granulites, which triggered years of discussion on fluid- absent or fluid-assisted granulite metamorphism. To some extent, this debate is a continuation of the former granite controversy, but it shows also how the famous battle of ＂soaks against pontiffs＂ could have been easily avoided.

关键词： Granite controversyMetamorphic petrologyFluid inclusionsJ TouretGranulites

Mehler's formula and functional calculus Dedicated to Professor Jean-Yves Chemin on the Occasion of His 60th Birthday

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2019年第6期62卷 1143-1166页

作者： Nicolas Lerner Department of Mathematics Sorbonne Université

We show that Mehler's formula can be used to handle several formulas involving the quantization of singular Hamiltonians. In particular, we diagonalize in the Hermite basis the Weyl quantization of the characteristic ... 详细信息

关键词： Mehler’s formula quantization rough Hamiltonians

Changes in temperature extremes over China under 1.5 ℃ and 2 ℃ global warming targets

在线全文

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2018年第2期9卷 120-129页

作者： SHI Chen JIANG Zhi-Hong CHEN Wei-Lin Laurent LI Key Laboratory of Meteorological Disaster of Ministry of Education Joint International Research Laboratory of Climate and Environment Change Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disaster Nanjing University of Information Science & Technology Nanjing 210044 China Laboratoire de Mbteorologie Dynamique CNRS Sorbonne Universites UPMC Universite Paris 06 Paris 75005 France

The long-term goal of the 2015 Paris Agreement is to limit global warming to well below 2 ℃above pre-industrial levels and to pursue efforts to limit it to 1.5 ℃. However, for climate mitigation and adaption efforts, further studies are still needed to understand the regional consequences between the two global warming limits. Here we provide an assessment of changes in temperature extremes over China （relative to 1986-2005） at 1.5 ℃ and 2 ℃ warming levels （relative to 1861-1900） by using the 5th phase of the Coupled Model Intercomparison Project （CMIP5） models under three RCP scenarios （RCP2.6, RCP4.5, RCP8.5）. Results show that the increases in mean temperature and temperature extremes over China are greater than that in global mean temperature. With respect to 1986-2005, the temperature of hottest day （TXx） and coldest night （TNn） are projected to increase about 1/1.6 ℃ and 1.1/1.8 ℃, whereas warm days （TX90p） and warm spell duration （WSDI） will increase about 7.5/13.8% and 15/30 d for the 1.5/2 ℃ global warming target, respectively. Under an additional 0.5 ℃ global warming, the projected increases of temperature in warmest day/night and coldest day/night are both more than 0.5 ℃ across almost the whole China. In Northwest China, Northeast China and the Tibetan Plateau, the projected changes are particularly sensitive to the additional 0.5 ℃ global warming, for example, multi-model mean increase in coldest day （TXn） and coldest night （TNn） will be about 2 times higher than a change of 0.5 ℃ global warming. Although the area-averaged changes in temperature extremes are very similar for different scenarios, spatial hotspot still exists, such as in Northwest China and North China, the increases in temperatures are apparently larger in RCP8.5 than that in RCP4.5.

关键词： 1.5 ℃ global warming 2 ℃ global warming Temperature extremes CMIP5 China

Mobility affects copulation and oviposition dynamics in Pieris brassicae in seminatural cages

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 2019年第4期26卷 743-752页

作者： Nicolas Larranaga Michel Baguette Olivier Calvez Delphine Legrand Centre National de la Recherche Scientifique and Universite Paul Sabatier Toulouse III SETE Station d'Ecologie Theorique et Experimentale UMR 5321 Moulis France Museum National d'Histoire Naturelle (sorbonne universites) Institut de Systematique Evolution et Biodiversite UMR 7205 57 rue Cuvier 75005 Paris cedex 5 France

When, how often and for how long organisms mate can have strong consequences for individual fitness and are crucial aspects of evolutionary ecology. Such determinants are likely to be of even greater importance in monandrous species and species with short adult life stages. Previous work suggests that mobility, a key dispersal? related trait, may affect the dynamics of copulations, but few studies have investigated the impact of individual mobility on mating latency, copulation duration and oviposition latency simultaneously. In this paper, we monitored the copulation dynamics of 40 males and 40 females, as well as the oviposition dynamics of the females of the Large White butterfly Pieris brassicae, a facultative long-distance disperser butterfly. Individuals from a breeding were selected to create a uniform distribution of mobility and we recorded the timing, number and duration of all copulations in a semiexperimental system. We showed that mobility, measured as the time spent in flight under stressful conditions (a proxy of dispersal tendency), correlates with all aspects of copulation dynamics: mobile males and females mated earlier and for shorter periods than less mobile individuals. In turn, late mating females increased the time between copulation and oviposition. These results feed the previously described mobility syndrome of R brassicae, involving morphological and physiological characters, with life-history traits. We suggest that the reduction of mating latency and copulation duration has an adaptive value in dispersing individuals, as their life expectancy might be shorter than that of sedentary individuals.

关键词： copulation duration life history mating latency mobility syndrome oviposition latency Pieris brassicae

From granulite fluids to quartz-carbonate megashear zones:The gold rush

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 747-758页

作者： Bin Fu Jacques L.R.Touret Research School of Earth Sciences The Australian National University Institut de Mineralogie.de Physique des Materiaux et de Cosmochimie(IMPMC) Sorbonne Universites UPMC Univ Paris 06.UMR CNRS 7590 Museum National d'Histoire Naturelle IRD UMR 206.4 Place Jussieu.F-75005 Paris.France

At peak granulite-facies metamorphic conditions, lower continental crust is arguably fluxed by large amounts of two key low water activity fluids：（i） high-density CO2 and/or （ii） concentrated saline so- lutions. These fluids are either internally-derived, generated by mineral reactions or dehydration melting or, notably for CO2, externally-derived, issued from the underlying mantle. Postmetamorphic evolution results in complete disappearance of these fluids, except for minute remnants preserved in minerals as fluid inclusions. Two major processes are involved：（i） at peak conditions, granitoid magmas form, migrate upward, and crystallize as shallow intrusions in the upper crust （mineralized porphyry types or reduced intrusions）; （ii） during the rapid decompression which almost systematically follows a period of post-peak isobaric cooling, especially for ultrahigh-temperature granulites （anticlockwise P-T paths）, quartz-carbonate megashear zones are formed by repeated periods of seismic activity. Seismic activity may continue until all free fluids have disappeared, resulting in the ultramylonites and pseudotachylites that are found in many granulite domes. A great majority of vein-type Au deposits worldwide occur in the above-mentioned settings or nearby. We suggest that the Au has been scavenged by the granulite fluids, then redistributed and concentrated during the formation of veins and related phenomena.

关键词： Granulite CO2 BrinesMegashear zonesAu mineralization

Flocculation and magnetically-assisted sedimentation of size-sorted beidellite platelets mixed with maghemite nanoparticles

在线全文

学校读者我要写书评

暂无评论

Nano Research 2020年第11期13卷 3001-3011页

作者： Sofia Housni Sébastien Abramson Jean-Michel Guigner Pierre Levitz Laurent Michot Laboratoire de PHysico-chimie des Electrolytes et Nanosystèmes InterfaciauX(PHENIX UMR 8234 Sorbonne Université-CNRS)Sorbonne UniversitéParis75252France Institut de Minéralogie de Physique des Matériaux et de Cosmochimie(IMPMC UMR 7590Sorbonne Université-IRD-CNRS-MNHN)Sorbonne UniversitéParis75252France

In this study,the flocculation and the subsequent decantation step of mixed suspensions of 10 nm-sizedγ-Fe_(2)O_(3) magnetic nanoparticles and 500 nm-sized beidellite clay platelets was *** work may find application in the field of water treatment,specifically the flocculation processes with magnetically assisted *** a short description of the preparation and characterization of the raw materials(nanoparticles and clays),the influence of several parameters(pH,concentrations of nanoparticles and clays etc.)on the amount of flocculated materials was examined,which gave information on the concentration ranges allowing a complete flocculation,together with a better understanding on the interactions between nanoparticles and clays responsible for *** optimal conditions for magnetically assisted settling were then determined by comparing for each sample sedimentation velocities under gravity and in the presence of a Nd-Fe-B ***,the complex multiscale structure of the flocs in water was explored,through the measurement of several bulk properties(zeta-potential and volume measurements,laser granulometry),while the organization of the materials at a microscopic scale was investigated by cryo-transmission electron microscopy(cryo-TEM)and small-angle X-ray scattering(SAXS).

关键词： magnetic separation nanoparticles clay flocculation decantation characterization

Palcernuine, the first [5/6/6/6]-cernuane-type alkaloid from Palhinhaea cernua ***

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 Chemical Letters 2016年第6期27卷 969-973页

作者： Yu Tang Juan Xiong Yike Zou Bastien Nay Li-Jun Wang Jin-Feng Hu Department of Natural Products Chemistry School of PharmacyFudan UniversityShanghai 201203China Department of Chemistry University of PennsylvaniaPhiladelphia 19104-6323USA Unite Molecules de Communication et Adaptation des Micro-organismes Sorbonne UniversitesMuseum National d'Histoire NaturelleCentre National de la Recherche Scientifique(CNRS UMR 7245)Paris 75005France

One novel（named palcernuine, 1） and five known cernuane-type（2–6） alkaloids were isolated from the whole plant of Palhinhaea cernua f. sikkimensis. The structure of 1, possessing an unprecedented [5/6/6/6]-tetracyclic ring system containing two nitrogen atoms, was established on the basis of spectroscopic methods, and its absolute configuration was determined by comparison of the experimental and calculated electronic circular dichroism（ECD） spectra. A plausible biosynthetic pathway to 1 is proposed.

关键词： Palhinhaea cernua f.sikkimensis Lycopodiaceae Palcernuine Cernuane-type alkaloids Biosynthetic pathway

Analytical modelling of the expansion of a solid obstacle interacting with a radiative shock

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2018年第2期6卷 123-132页

作者： Th.Michel E.Falize B.Albertazzi G.Rigon Y.Sakawa T.Sano H.Shimogawara R.Kumar T.Morita C.Michaut A.Casner R Barroso P.Mabey Y.Kuramitsu S.Laffite L.Van Box Som G.Gregori R.Kodama N.Ozaki P.Tzeferacos D.Lamb M.Koenig luli-cnrs ecole polytechniquecea:universite paris-saclayupmc univ paris 06:sorbonne universites-f-91128 palaiseau cedexFrance cea damdifF-91297 ArpajonFrance cea saclay dsm/irfu/service d'astrophysiqueF-91191 Gif-sur-YvetteFrance institute of laser engineering osaka universitySuitaOsaka 565-0871Japan faculty of engineering sciences kyushu university6-1 Kasuga-KoenKasugaFukuoka 816-8580Japan luth observatoire de parispsl research universitycnrsuniversite paris diderotSorbonne Paris Cite92190 MeudonFrance universite de bordeaux-cnrs-cea celia UMR 5107F-33405 TalenceFrance gepi observatoire de parispsl research universitycnrsuniversite paris diderotSorbonne Paris Cite75014 ParisFrance graduate school of engineering osaka universitySuitaOsaka 565-0871Japan lerma observatoire de parispsl research universitycnrssorbonne universitesUPMC Univ.Paris 06F-75005 ParisFrance clarendon laboratory university of oxfordParks RoadOxford OX1 3PUUK flash center for computational science university of chicagoIL 60637USA

In this paper, we present a model characterizing the interaction of a radiative shock(RS) with a solid material, as described in a recent paper(Koenig et al., Phys. Plasmas, 24, 082707(2017)), the new model is then related to recent experiments performed on the GEKKO XII laser facility. The RS generated in a xenon gas cell propagates towards a solid obstacle that is ablated by radiation coming from the shock front and the radiative precursor, mimicking processes occurring in astrophysical phenomena. The model presented here calculates the dynamics of the obstacle expansion,which depends on several parameters, notably the geometry and the temperature of the shock. All parameters required for the model have been obtained from experiments. Good agreement between experimental data and the model is found when spherical geometry is taken into account. As a consequence, this model is a useful and easy tool to infer parameters from experimental data(such as the shock temperature), and also to design future experiments.

关键词： high energy density physics laser–plasmas interaction modelling plasmas astrophysics plasma physics radiative hydrodynamics radiative shock