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Post-synthesis phase and shape evolution of CsPbBr3 colloidal nanocrystals: The role of ligands

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Nano Research 2019年第5期12卷 1155-1166页

作者： Elisabetta Fanizza Francesca Cascella Davide Altamura Cinzia Giannini Annamaria Panniello Leonardo Triggiani Francesca Panzarea Nicoletta Depalo Roberto Grisorio Gian Paolo Suranna Angela Agostiano M.Lucia Curri Marinella Striccoli dipartimento di Chimica Università degli Studi di Bari "A.Moro"Via Orabona 470126 BariItaly cnr-istituto per i Processi Chimico Fisici S.S.BariVia Orabona470126 BariItaly cnr-istituto di Cristallografia Via Amendola122/O70126 BariItaly ydipartimento di Ingegneria Civile Ambientaledel TerritorioEdile e di Chimica(DICATECh)Politecnico di BariVia Orabona 470125Italy cnr-nanotec-istituto di nanotecnologia Via Monteroni 73100 LecceItaly

The surface chemistry of colloidal cesium lead bromide (CsPbBr3) nanocrystals is decisive in determining the stability and the final morphology of this class of materials,characterized by ionic structure and a high defect tolerance ***,the high sensitivity of purified colloidal nanocubes of CsPbBr3 to diverse environmental condition (solvent dilution,ageing,ligands post synthetic treatment) in ambient atmosphere is investigated by means of a comprehensive morphological (electron microscopy),structural (θ/2θ X-ray diffraction (XRD) and grazing incidence wide angle scattering (GIWAXS)),and spectroscopic chemical (1H nuclear magnetic resonance (NMR),nuclear Overhauser effect spectroscopy (NOESY),absorption and emission spectroscopy) *** aging and solvent dilution contribute to modify the nanocrystal morphology,due to a modification of the ligand ***,we establish the ability of aliphatic carboxylic acids and aikyl amines ligands to induce,even in a post preparative process at room temperature,structural,morphological and spectroscopic *** post synthesis alkyl amine addition,in particular of oleyl amine and octyl amine,the highly green emitting CsPbBr3 nanocubes effectively tum into one-dimensional (1 D) thin tetragonal nanowires or lead halide deficient rhombohedral zero-dimensional (0D) Cs4PbBr6 structures with a complete loss of *** addition of an alkyl carboxylic acid,as oleic and nonanoic acid,produces the transformation of nanocubes into still emitting orthorombic two-dimensional (2D) *** acid/base equilibrium between the native and added ligands,the edsorbed/free ligands dynamic in solution and the ligand solubility in non-polar solvent contribute to render CsPbBr3 particularly sensitive to environmental and processing conditions and,therefore prone to undergo to structural,morphological and,hence spectroscopic,transformations.

关键词： lead halide perovskite nanocrystals surface chemistry ligands equilibria long term stability

Fault on-off versus strain rate and earthquakes energy

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Geoscience Frontiers 2015年第2期6卷 265-276页

作者： C.Doglioni S.Barba E.Carminati F.Riguzzi dipartimento di Scienze della Terra Università Sapienza istituto di Geologia Ambientale e Geoingegneria CNR istituto Nazionale di Geofisica e Vulcanologia

We propose that the brittle-ductile transition （BDT） controls the seismic cycle. In particular, the movements detected by space geodesy record the steady state deformation in the ductile lower crust, whereas the stick-slip behavior of the brittle upper crust is constrained by its larger friction. GPS data allow analyzing the strain rate along active plate boundaries. In all tectonic settings, we propose that earthquakes primarily occur along active fault segments characterized by relative minima of strain rate, segments which are locked or slowly creeping. We discuss regional examples where large earthquakes happened in areas of relative low strain rate. Regardless the tectonic style, the interseismic stress and strain pattern inverts during the coseismic stage. Where a dilated band formed during the interseismic stage, this will be shortened at the coseismic stage, and vice-versa what was previously shortened, it will be dilated. The interseismic energy accumulation and the coseismic expenditure rather depend on the tectonic setting （extensional, contractional, or strike-slip）. The gravitational potential energy dominates along normal faults, whereas the elastic energy prevails for thrust earthquakes and performs work against the gravity force. The energy budget in strike-slip tectonic setting is also primarily due elastic energy. Therefore, precursors may be different as a function of the tectonic setting. In this model, with a given displacement, the magnitude of an earthquake results from the coseismic slip of the deformed volume above the BDT rather than only on the fault length, and it also depends on the fault kinematics.

关键词： Earthquake generation mode Strain rate Brittle-ductile transition Earthquake energy

The Space and Time Features of Global SST Anomalies Studied by Complex Principal Component Analysis

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Advances in Atmospheric Sciences 1999年第1期16卷 3-23,5+9+11+15+17+19+21页

作者：骆美霞 dipartimento di Fisica Generale Universita di Torino Turin Italy and Istituto di Cosmogeofisica del CNR Turin Italy

In this paper, the variability characteristics of the global field of sea surface temperature (SST) anomaly are studied by complex principal component (c.p.c.) analysis, whose results are also compared with those of real p.c. analysis. The data consist of 40 years of global SST monthly averages over latitudes from 42 5°S to 67 5°N. In the spatial domain, it is found that the distribution of the first complex loading amplitude is characterized by three areas of large values: the first one in the eastern and central equatorial Pacific Ocean, the second one in the northern tropical Indian Ocean and South China Sea, the third one in the northern Pacific Ocean. As it will be explained, this pattern may be considered as representative of El Nio mode. The first complex loading phase pattern shows a stationary wave in the Pacific (also revealed by real p.c. analysis) superimposed to an oscillating disturbance, propagating from the Pacific to Indian or the opposite way. A subsequent correlation analysis among different spatial points allows revealing disturbances actually propagating westward from the Pacific to the Indian Ocean, which could therefore represent reflected Rossby waves, i.e. the west phase of the signals that propagate disturbances of thermal structure in the tropical Pacific Ocean. In the time domain, a relation between the trend of the first complex principal component and the ENSO cycle is also established.

关键词： Global sea surface temperature anomalies ENSO Complex principal component analysis Travelling disturbances

Plasmon-enhanced rotational dynamics of anisotropic core-shell polymeric-metallic microparticles

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Photonics Research 2022年第12期10卷 2734-2742页

作者： NICOLA PELLIZZI ALFREDO MAZZULLA PASQUALE PAGLIUSI GABRIELLA CIPPARRONE Physics Department University of Calabria87036 Rende(CS)Italy cnr—istituto di nanotecnologia-sede secondaria di Rende(CS) Italy

The development of efficient and cost-effective micromachines is a challenge for applied and fundamental science,given their wide fields of *** is a suitable tool to move small objects in a noncontact way,given its capabilities in exerting forces and ***,when complex manipulation is required,micro-objects with proper architecture could play a specific *** we report on the rotational dynamics of core-shell particles,with a polymeric nematic core of ellipsoidal shape capped by Au *** undergo a peculiar synchronous spinning and orbital motion when irradiated by a simple Gaussian beam,which originates from the coupling of the metallic nanoparticles’optical response and the core *** rotation capabilities are strongly enhanced when the trapping wavelength lies in the plasmonic resonance region:indeed,the spin kinetic energy reaches values two orders of magnitude larger than the one of bare *** proposed strategy brings important insights into optimizing the design of light controlled micro-objects and might benefit applications in microfluidics,microrheology,and micromachining involving rotational dynamics.

关键词： metallic dynamics anisotropic

Fault on-off versus coseismic fluids reaction

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Geoscience Frontiers 2014年第6期5卷 767-780页

作者： C.Doglioni S.Barba E.Carminati F.Riguzzi dipartimento di Scienze della Terra Università SapienzaRomaItaly istituto di Geologia Ambientale e Geoingegneria CNRRomaItaly istituto Nazionale di Geofisica e Vulcanologia RomaItaly

The fault activation （fault on） interrupts the enduring fault locking （fault off） and marks the end of a seismic cycle in which the brittle-ductile transition （BDT） acts as a sort of switch. We suggest that the fluid flow rates differ during the different periods of the seismic cycle （interseismic, pre-seismic, coseismic and post-seismic） and in particular as a function of the tectonic style. Regional examples indicate that tectonic-related fluids anomalies depend on the stage of the tectonic cycle and the tectonic style. Although it is difficult to model an increasing permeability with depth and several BDT transitions plus independent acquicludes may occur in the crust, we devised the simplest numerical model of a fault constantly shearing in the ductile deeper crust while being locked in the brittle shallow layer, with variable homogeneous permeabilities. The results indicate different behaviors in the three main tectonic settings. In tensional tectonics, a stretched band antithetic to the normal fault forms above the BDT during the interseismic period. Fractures close and fluids are expellecl during the coseismic stage. The mechanism reverses in compressional tectonics. During the interseismic stage, an over-compressed band forms above the BDT. The band dilates while rebounding in the coseismic stage and attracts fluids locally. At the tip lines along strike-slip faults, two couples of subvertical bancls show different behavior, one in dilationJcompression and one in compressionJdilation. This deformation pattern inverts during the coseismic stage. Sometimes a pre-seismic stage in which fluids start moving may be observed and could potentially become a precursor.

关键词： Fault activation BritUe-ductile transition EarthquakeFluids response

Detection of Proper Motion in OQ208

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Chinese Physics Letters 2000年第4期17卷 307-309页

作者：刘祥 C.Stanghellini D.Dallacasa M.Bondi Urumqi Astronomical Observatoryj National Astronomical Observatories Chinese Academy of SciencesUrumqi 830011 istituto di Radioastronomia del cnrt Notot Italy Uhiversita di Bolognaf Italy istituto di Radioastronomia del cnr Bolognat Italy

We report on an ongoing work aimed to detect the separation speed of the two hot-spots of the compact symmetric object *** images at 8.4 GHz taken in 6 epoches between 1994 and 1997 we obtain an estimate of 0.058±-0.038 mas/year as the relative motions between two components of the radio *** the red-shift of OQ208 I mas correspond to 1pc,thus we obtain a projected jet speed of 0.095±*** an inclination of 45°between the jets and the line of sight,we have an actual jet velocity of 0.134±0.088c and therefore the kinematic age of the source is so young of 320±210 years.

关键词： OQ epoch separation

Rock temperature variability in high-altitude rockfall-prone areas

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Journal of Mountain Science 2022年第3期19卷 798-811页

作者： Guido NIGRELLI Marta CHIARLE Andrea MERLONE Graziano COPPA Chiara MUSACCHIO Consiglio Nazionale delle Ricerche(cnr) Istituto di Ricerca per la Protezione Idrogeologica(IRPI)Torino 10135Italy istituto Nazionale di Ricerca Metrologica(INRiM) Torino 10135Italy

In a context of cryosphere degradation caused by climate warming,rock temperature is one of the main driving factors of rockfalls that occur on high-elevation mountain *** order to improve the knowledge of this critical relationship,it is necessary to increase measurement capability of rock temperature and its variability in different lithological and slope/aspect conditions,and also to increase local scale studies,increasing the quality and the comparability of the *** paper shows an example of metrological characterization of sensors used for rock temperature measurement in mountain regions,by means of the measurement *** such approach,data and results from temperature measurements carried out in the Bessanese high-elevation experimental site(Western European Alps)are *** procedures for the calibration and field characterization of sensors allow to measure temperature in different locations,depths and lithotypes,within 0.10°C of overall *** work has highlighted that metrological traceability is fundamental to asses data quality and establish comparability among different measurements;that there are strong differences between air temperature and near-surface rock temperature;and that there are significant differences of rock temperature acquired in different aspect ***,solar radiation,slope/aspect conditions and lithotype,seem to be the main driving factors of rock temperature.

关键词： Rock temperature Rockfalls European Alps Climate warming Temperature measurement

The formation and growth mechanisms of young back-arc spreading ridges from high-resolution bathymetry:The Marsili Seamount(Tyrrhenian Sea,Italy)

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Geoscience Frontiers 2024年第1期15卷 325-338页

作者： Eugenio Nicotra Salvatore Passaro Guido Ventura dipartimento di Biologia Ecologia e Scienze della Terra Universitàdella Calabria87036 Arcavacata di RendeCosenzaItaly istituto di Scienze Marine cnr 80133 NapoliItaly istituto Nazionale di Geofisica e Vulcanologia 00143 RomaItaly istituto per lo Studio degli impatti Antropici e Sostenibilitáin ambiente marino cnr 91026 Capo GranitolaTrapaniItaly

The formation and growth mechanisms of Mid-Ocean Ridges(MOR)are relatively well known,whereas those of back-arc spreading ridges are comparatively less known because geophysical,geochemical,and morphological data are scarce and of low *** we present a high-resolution bathymetry of the Marsili Seamount(MS;1 Ma-3 ka),which represents the inflated spreading ridge of the 2 Ma old Marsili back-arc basin associated to the subduction of the Ionian Sea below the Calabrian Arc and Tyrrhenian *** is 70 km long,30 km wide,and its height reaches about 3000 m from surrounding *** new digital bathymetric model has a 5 m grid cell size resolution and covers the MS bathymetry from-1670 mbsl to the top at-491 *** conduct morphometric and morphological analyses of the bathymetry and recognize landforms due to volcanic,tectonic,hydrothermal and gravity *** consists of volcanoes related to fissural and central-type activity,this latter located at the northern and southern tips of the main dike *** swarms represent the surface expression of different ridge segments whose strikes are controlled by the larger scale back-arc spreading processes and by the local occurrence of an active hydrothermal *** latter develops in a flat area between two partly overlapping ridge segments where historical volcanism and extensional processes *** ridges represent the embryonic stage of the formation of transform-like *** volcanoes,the northern of which is characterized by a caldera,form at the tips of MS because the decrease in width of the major volcanic fissures promotes vent localization associated with the formation of sill-like reservoirs from which central-type vents may *** processes affecting the MS flanks are due to shallow seafloor *** collapses affecting the northernmost central-type polygenic volcano must be included in the evaluation of the hazard related to potential *** dipping faul

关键词： Back-arc spreading ridge Morphology Tectonics Volcanism Marsili seamount

Superluminal X-waves in a polariton quantum fluid

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Light(Science & Applications) 2017年第1期6卷 311-319页

作者： Antonio Gianfrate Lorenzo Dominici Oksana Voronych Michał Matuszewski Magdalena Stobińska Dario Ballarini Milena De Giorgi Giuseppe Gigli Daniele Sanvitto cnr nanotec Istituto di NanotecnologiaVia Monteroni73100 LecceItaly Institute of Theoretical Physics and Astrophysics University of Gdańskul.Wita Stwosza 5780-952 GdańskPoland Institute of Physics Polish Academy of SciencesAl.Lotników 32/4602-668 WarsawPoland Faculty of Physics University of WarsawPasteura 502-093 WarsawPoland INFN sezione di Lecce73100 LecceItaly

In this work,we experimentally demonstrate for the first time the spontaneous generation of two-dimensional exciton-polariton X-waves.X-waves belong to the family of localized packets that can sustain their shape without spreading,even in the linear *** allows the wavepacket to maintain its shape and size for very low densities and very long times compared to soliton waves,which always necessitate a nonlinearity to compensate the ***,we exploit the polariton nonlinearity and uniquely structured dispersion,comprising both positive-and negative-mass curvatures,to trigger an asymmetric four-wave mixing in momentum *** ultimately enables the self-formation of a spatial X-wave *** ultrafast imaging experiments,we observe the early reshaping of the initial Gaussian packet into the X-pulse and its propagation,even for vanishingly small *** allows us to outline the crucial effects and parameters that drive the phenomena and to tune the degree of superluminal propagation,which we found to be in close agreement with numerical simulations.

关键词： negative mass nonlinearity polaritons superluminal X-waves