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Analysis of Tonal Noise Generating Mechanisms in Low-Speed Axial-Flow Fans

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Journal of Thermal Science 2016年第4期25卷 302-311页

作者： Edward Canepa Andrea Cattanei Fabio Mazzocut Zecchin diME-universita di genova via Montallegro 1 1-16145 Genoa Italy

The present paper reports a comparison of experimental SPL spectral data related to the tonal noise generated by axial-flow fans.A nine blade rotor has been operated at free discharge conditions and in four geometrical configurations in which different kinds of tonal noise generating mechanisms are present:large-scale inlet turbulent structures,tip-gap flow,turbulent wakes,and rotor-stator *** measurements have been taken in a hemi-anechoic chamber at constant rotational speed and,in order to vary the acoustic source strength,during low angular acceleration,linear speed *** order to avoid erroneous quantitative evaluations if the acoustic propagation effects are not considered,the acoustic response functions of the different test configurations have been computed by means of the spectral decomposition ***,the properties of the tonal noise generating mechanisms have been *** this aim,the constant-Strouhal number SPL,obtained by means of measurements taken during the speed ramps,have been compared with the propagation ***,the analysis of the phase of the acoustic pressure has allowed to distinguish between random and deterministic tonal noise generating mechanisms and to collect information about the presence of important propagation effects.

关键词： Axial-flow fans Tonal noise Acoustic response

Plasmon hybridization engineering in self-organized anisotropic metasurfaces

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Nano Research 2018年第7期11卷 3943-3956页

作者： Maria C. Giordano Stefano Longhi Matteo Barelli Andrea Mazzanti Francesco Buatier de Mongeot Giuseppe Della Valle dipartimento di Fisica Universita di Genova Via Dodecaneso 33 Genova I-16146 Italy dipartimento di Fisica and IFN-CNR Politecnico di Milano Piazza L. da Vinci 32 Milano 1-20133 Italy

The engineering of self-organized plasmonic metasurfaces is demonstrated using a maskless technique with defocused ion-beam sputtering and kinetically controlled deposition. The proposed reliable, cost-effective, and controllable approach enables large-area （order of square centimeter） sub-wavelength periodic patterning with close-packed gold nanostrips. A multi-level variant of the method leads to high-resolution manufacturing of vertically stacked nanostrip dimer arrays, without resorting to lithographic approaches. The design of these self-organized metasurfaces is optimized by employing plasmon hybridization methods. In particular, preliminary results on the so-called gap-plasmon configuration of the nanostrip dimers, implementing magnetic dipole resonance in the near-infrared range, are reported. This resonance offers a superior sensitivity and field enhancement, compared with the more conventional electric dipole resonance. The translational invariance of the nanostrip configuration leads to a high filling factor of the hot spots. These advanced features make the large-area metasurface based on gap-plasmon nanostrip dimers very attractive for surface-enhanced linear and nonlinear spectroscopy （e.g., surface-enhanced Raman scattering） and plasmon-enhanced photon harvesting in solar and photovoltaic cells.

关键词： metasurfaces self-organization gold nanostructures plasmon hybridization gap plasmon resonances

OXIDATION OF A TWO-PHASE Cu-75Cr ALLOY IN AIRAT 700-900℃

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Acta Metallurgica Sinica(English Letters) 1997年第4期10卷 333-341页

作者： F. Gesmundo Y Niu F. Vianiand D.L. Douglass(universita di genova, Fiera del Mare, Pad. D,16129 genova, Italy)(State Key Lab. for Corrosion and Protection, Institute of Corrosion and Protection of Metals, theChinese Academy of Sciences, Shenyang 110015, Ch Univ di genova Genova Italy

The cormsion in air of a two-phase Cu-75Cr alloy was studied at 700-900℃. Thealloy cormded nearly parabolically at 700-800℃, but at 900℃ its instantaneousparabolic mte constant decreased with time. The scales were complex and consistedof an outermost layer of copper oxide generally followed bg a layer of the double ox-ide Cu2 Cr2 O4 sometimes containing particles of unoxidized chromium surmunded bya chromia layer. An innermost layer of chromia was also observed in some *** metallic copper was al8o frequently mixed with chromia particles. No Cr de-pletion was observed in the alloy close to the inteffoce with the scale. In any case,this alloy was not able to form an exclusive continuous protective chromia layer. Thespecial cormsion behavior Of this alloy is typical of two-phase binary systems with alange solubility gaP in which the outwaof dthesion fiux of the most-reactive componentin the alloy is strongly reduced and may be inswncient to fOrm a protective externallayer of the cormsponding oxide. In paTticular, the presence of particles of Cr withina double oxide layer is very unusual and is allowed only for the kinetic reason.

关键词： copper-chromium alloy two-phase oxidation

Influence of Surface Finishing on High-Temperature Oxidation of AISI Type 444 Ferritic Stainless Steel Used in SOFC Stacks

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Acta Metallurgica Sinica(English Letters) 2017年第8期30卷 697-711页

作者： Valeria Bongiorno Paolo Piccardo Simone Anelli Roberto Spotorno Laboratorio di Metallurgia e Materiali - dipartimento di Chimica e Chimica Industriale (LMM-DCCI) Universita degli Studi di Genova Via Dodecaneso 31 16146 GenoaItaly

This research is focused on the study of the samples, approximatively 15 × 30 mm^2 sized, that were mechanically cut from two sheets （0.4 and 0.2 mm thick, respectively） of AIS1444 Type ferritic stainless steel （FSS）（diN 1.4521, Eu designation X2CrMoTil8-2）; this material was in the ＇as-rolled＇ state. Part of these specimens were treated superficially on one side using abrasive SiC papers with different average grit sizes （i.e., 46.2, 30.2, 18.3 gm） and diamond suspension （up to 1 tim） in order to obtain various surface roughness. Both the ＇as-rolled＇ and superficially treated samples were then aged in a muffle fumace in static air according to a thermal cycle corresponding to the curing phase of an experimental glass used as sealing in the solid oxide fuel cell stacks. After aging, the chemical compositions and mor- phological peculiarities of the scale formed depending on the thickness of the samples and their surface state were studied by scanning electron microscopy, energy-dispersive spectroscopy, micro-Raman spectroscopy, bright field light optical microscopy. The obtained results show that all scales formed consist of an inner Cr2O3 subscale and an outer （Mn,Cr）3O4 spinel layer; the relationship between FSS grain size and scale microstructural features is consistent on the samples with mirror-like surface only; the scale thicknesses on SiC grinded samples are comparable; the scales covering the ＇as-rolled＇ surfaces are morphologically similar to those grown on the surfaces finished with the 30.2 and 18.3 μm SiC papers, and their thicknesses show an intermediate situation between the abraded and the mirror-like specimens. The last described characteristics depend mainly on the surface and microstructural peculiarities resulting from the rolling process.

关键词： AISI Type 444 SOFC stacks Surface roughness Microstructure Surface finishing High-temperature oxidation

Corrosion of Y, Fe and Fe-15Y in H_2-H_2S Mixture under 10^(-3)Pa S_2 at 600～800℃

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Journal of Materials Science & Technology 1996年第5期12卷 321-328页

作者： Yan NIU Weitao WU and Chaoliu ZENG (State Key Lab. for Corrosion and Protection, Institute of Corrosion and Protection of Metals,Chinese Academy of Sciences, Shenyang 110015, China)F. Gesmundo and F. Viani (Instituto di Chimica, Facolta di Ingegneria, Un State Key Lab. for Corrosion and Protection Institute of Corrosion and Protection of Metals Chinese Academy of Sciences Shenyang 110015 China Instituto di Chimica Facolta di Ingegneria Universita di Genova 16129 Genova Fiera del Mare. Pad. D Italy

The corrosion of an Fe-based alloy containing 15 wt pct Y in H2-H2S mixtures under 10-3 Pa S2 was studied at 600~800℃ in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneflcial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus,Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition. but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12~17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe

关键词： Fe and Fe-15Y in H2-H2S Mixture under 10 Met OO Pa S2 at 600 Corrosion of Y

Free-stream Turbulence Effects on the Boundary Layer of a High-lift Low-Pressure-Turbine Blade

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Journal of Thermal Science 2016年第3期25卷 195-206页

作者： Simoni D. Ubaldi M. Zunino p. Ampellio E. diME-universita di genova Via MontaUegro 11-16145 GenovaItaly GE AvioAero S.p.A. V.I Maggio99 1-10040 Rivalta(TO)-Italy

The suction side boundary layer evolution of a high-lift low-pressure turbine cascade has been experimentally in- vestigated at low and high free-stream turbulence intensity conditions. Measurements have been carded out in order to analyze the boundary layer transition and separation processes at a low Reynolds nttmber, under both steady and unsteady inflows. Static pressure distributions along the blade surfaces as well as total pressure distri- butions in a downstream tangential plane have been measured to evaluate the overall aerodynamic efficiency of the blade for the different conditions. Particle. Image Velocimetry has been adopted to analyze the time-mean and time-varying velocity fields. The flow field has been surveyed in two orthogonal planes （a blade-to-blade plane and a wall-parallel one）. These measurements allow the identification of the Kelvin-Helmholtz large scale cohe- rent structures shed as a consequence of the boundary layer laminar separation under steady inflow, as well as the investigation of the three-dimensional effects induced by the intermittent passage of low and high speed streaks. A close inspection of the time-mean velocity profiles as well as of the boundary layer integral parameters helps to characterize the suction side boundary layer state, thus justifying the influence of free-stream turbulence intensity on the blade aerodynamic losses measured under steady and unsteady inflows.

关键词： profile losses high-lift profiles free-stream turbulence streaks unsteady flows.

Large-area flexible nanostripe electrodes featuring plasmon hybridization engineering

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Nano Research 2021年第3期14卷 858-867页

作者： Carlo Mennucci Debasree Chowdhury Giacomo Manzato Matteo Barelli Roberto Chittofrati Christian Martella Francesco Buatier de Mongeot dipartimento di Fisica Universitàdegli Studi di Genovavia Dodecaneso 33I-16146GenovaItaly

Multifunctional flexible Au electrodes based on one-dimensional(1D)arrays of plasmonic gratings are nanofabricated over large areas with an engineered variant of laser interference lithography optimized for low-cost transparent *** nanostripe(NS)arrays achieve sheet resistance in the order of 20 Ohm/square on large areas(∼cm^(2))and are characterized by a strong and dichroic plasmonic response which can be easily tuned across the visible(VIS)to near-infrared(NIR)spectral range by tailoring their cross-sectional *** vertically a second nanostripe,separated by a nanometer scale dielectric gap,we form near-field coupled Au/SiO_(2)/Au dimers which feature hybridization of their localized plasmon resonances,strong local field-enhancements and a redshift of the resonance towards the NIR *** possibility to combine excellent transport properties and optical transparency on the same plasmonic metasurface template is appealing in applications where low-energy photon management is mandatory like e.g.,in plasmon enhanced spectroscopies or in photon harvesting for ultrathin photovoltaic *** remarkable lateral order of the plasmonic NS gratings provides an additional degree of freedom for tailoring the optical response of the multifunctional electrodes via the excitation of surface lattice resonances,a Fano-like coupling between the broad localised plasmonic resonances and the collective sharp Rayleigh modes.

关键词： nanofabrication nanostripes transparent electrodes plasmonic dimers interference lithography surface lattice resonances

Sorafenib delivery nanoplatform based on superpara- magnetic iron oxide nanoparticles magnetically targets hepatocellular carcinoma

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Nano Research 2017年第7期10卷 2431-2448页

作者： Nicoletta Depalo Rosa Maria lacobazzi Gianpiero Valente Ilaria Arduino Silvia Villa Fabio Canepa Valentino Laquintana Elisabetta Fanizza Marinella Striccoli Annalisa Cutrignelli Angela Lopedota Letizia Porcelli Amalia Azzariti Massimo Franco Maria Lucia Curri Nunzio Denora Istituto per i Processi Chimico-Fisici-CNR UOS Bari Via Orabona 4 70125 Bari Italy Istituto Tumori IRCCS Giovanni Paolo II viale O. Flacco 65 70124 Bari Italy dipartimento di Chimica Universita degli Studi di Bad Aldo Moro Via Orabona70125 Bari Italy dipartimento di Farmacia-Scienze del Farmaco Universita degli Studi di Bari Aldo Moro Via Orabona 4 70125 Bari Italy dipartimento di Chimica e Chimica Industriale Universita di Genova Via Dodecaneso 31 16146 Genova Italy

Currently, sorafenib is the only systemic therapy capable of increasing overall survival of hepatocellular carcinoma patients. Unfortunately, its side effects, particularly its overall toxicity, limit the therapeutic response that can be achieved. Superparamagnetic iron oxide nanoparticles （SPIONs） are very attractive for drug delivery because they can be targeted to specific sites in the body through application of a magnetic field, thus improving intratumoral accumulation and reducing adverse effects. Here, nanoformulations based on polyethylene glycol modified phospholipid micelles, loaded with both SPIONs and sorafenib, were successfully prepared and thoroughly investigated by complementary techniques. This nanovector system provided effective drug delivery, had an average hydrodynamic diameter of about 125 nm, had good stability in aqueous medium, and allowed controlled drug loading. Magnetic analysis allowed accurate determination of the amount of SPIONs embedded in each micelle. An in vitro system was designed to test whether the SPION micelles can be efficiently held using a magnetic field under typical flow conditions found in the human liver. Human hepatocellular carcinoma （HepG2） cells were selected as an in vitro system to evaluate tumor cell targeting efficacy of the superparamagnetic micelles loaded with sorafenib. These experiments demonstrated that this delivery platform is able to enhance sorafenib＇s antitumor effectiveness by magnetic targeting. The magnetic nanovectors described here represent promising candidates for targeting specific hepatic tumor sites, where selective release of sorafenib can improve its efficacy and safety profile.

关键词： superparamagnetic ironoxide nanoparticles poly(ethylene glycol) (PEG)-modified phospholipidmicelles drug delivery magnetic targeting hepatocellular carcinoma sorafenib

Size contrast of Pt nanoparticles formed on neighboring domains within suspended and supported graphene

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Nano Research 2018年第3期11卷 1589-1598页

作者： Dario Roccella Matteo Amati Hikmet Sezen Rosaria Brescia Luca Gregoratti universita degli Studi di genova - Facolta di Scienze Matematiche Fisiche e Naturali Viale Benedetto XV Genova 3-16132 Italy Elettra - Sincrotrone Trieste S.C.p.A. in Area Science Park SS 14-Km 163.5 Trieste 34149 Italy Electron Microscopy Facility Istituto Italiano di Tecnologia (liT) via Morego 30 Genova 16163 Italy

The relatively small size of thin （one or few layers） graphene flakes makes it extremely difficult to study the behavior of suspended graphene by characterization techniques other than the electron microscopies. Herein, we exploited the capability of spatially resolved photoemission in combination with high resolution transmission electron microscopy to investigate the interaction of thermally evaporated Pt atoms on suspended and supported graphene. Spectroscopic and microscopic analyses reveal that the nucleation of nanometer- sized Pt particles in these two regions exhibit different trends. While only small nanometer-sized islands are present on the supported graphene, relatively larger clusters of islands were also found on the suspended flakes. The X-ray photoemission C ls core levels acquired after the Pt deposition show an increase in the number of vacancies in the graphene sheets.

关键词： graphene X-ray photoemissionspectroscopy scanning photoelectron microscop nanoparticles platinum suspended films