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排序方式: 共有168条查询结果,搜索用时 96 毫秒
1.
Maria Strakowska Panagiotis Chatzipanagiotou Gilbert De Mey Vasilis Chatziathanasiou Bogusław Więcek 《International Journal of Circuit Theory and Applications》2020,48(9):1523-1533
This paper deals with the identification of the thermal parameters of multilayer objects using the concept of thermal impedance. In order to perform such identification, temperature evolution in time is obtained by an infrared camera after power excitation is applied in the investigated structure. Infrared thermography offers the advantage of being a noncontact temperature detection and measurement method. In many practical cases, it is impossible to use contact temperature measurements. Typically, the power in the form of a step function is applied. In order to calculate the thermal impedance of an object, temperature and power are converted into the frequency domain using the Laplace transform for s = jω. Then, the poles of the thermal impedance are identified using vector fitting, which allows calculating the thermal impedance as a sum of partial fractions. This corresponds directly to the Foster network of a thermal object. In addition, the vector fitting method offers much better convergence in comparison with other methods using the polynomial rational approximation of thermal impedance. A considerable improvement of the numerical Laplace transform in high frequency range is proposed. In this approach, the variable s = jω is replaced by , and then, the integration result is corrected by the Taylor series. It leads to a kind of filtering of the temperature signal. 相似文献
2.
Matteo Di Giosia Alice Soldà Markus Seeger Andrea Cantelli Fabio Arnesano Maria I. Nardella Vincenzo Mangini Francesco Valle Marco Montalti Francesco Zerbetto Stefania Rapino Matteo Calvaresi Vasilis Ntziachristos 《Advanced functional materials》2021,31(20):2101527
Fullerenes are candidates for theranostic applications because of their high photodynamic activity and intrinsic multimodal imaging contrast. However, fullerenes suffer from low solubility in aqueous media, poor biocompatibility, cell toxicity, and a tendency to aggregate. C70@lysozyme is introduced herein as a novel bioconjugate that is harmless to a cellular environment, yet is also photoactive and has excellent optical and optoacoustic contrast for tracking cellular uptake and intracellular localization. The formation, water-solubility, photoactivity, and unperturbed structure of C70@lysozyme are confirmed using UV-visible and 2D 1H, 15N NMR spectroscopy. The excellent imaging contrast of C70@lysozyme in optoacoustic and third harmonic generation microscopy is exploited to monitor its uptake in HeLa cells and lysosomal trafficking. Last, the photoactivity of C70@lysozyme and its ability to initiate cell death by means of singlet oxygen (1O2) production upon exposure to low levels of white light irradiation is demonstrated. This study introduces C70@lysozyme and other fullerene-protein conjugates as potential candidates for theranostic applications. 相似文献
3.
Mark E. Barnes Geoff J. Daniell Paul Gow Vasilis Apostolopoulos 《Journal of Infrared, Millimeter and Terahertz Waves》2014,35(12):1030-1044
In this paper we model the carrier dynamics and resulting THz emission from lateral diffusion currents within a semiconductor device which has been partially masked by a metallic mask. We present a numerical 1D model and a 1D Monte Carlo simulation which both demonstrate that regardless of the excitation laser spot shape we do not expect to see measurable THz emission in the direction of the optical pump propagation from lateral diffusion currents. Experimentally such devices do produce strong THz emission. We analytically investigate the role of the metal mask and we found that it suppresses the emission of dipoles that are in a region that is less than a wavelength away from the interface. The results from the numerical model are also included in a finite element analysis model of the geometry which predicts THz emission if and only if the metal mask is present. 相似文献
4.
5.
Christina Plati Panos Georgiou Vasilis Papavasiliou 《Structure and Infrastructure Engineering》2016,12(9):1127-1136
This article aims to investigate the feasibility of incorporating of an artificial neural network (ANN) as an innovative technique for modelling the pavement structural condition, into pavement management systems. For the development of the ANN, strain assessment criteria are set in order to characterise the structural condition of flexible asphalt pavements with regards to fatigue failure. This initial task is directly followed with the development of an ANN model for the prediction of strains primarily based on in situ field gathered data and not through the usage of synthetic databases. For this purpose, falling weight deflectometer (FWD) measurements were systematically conducted on a highway network, with ground-penetrating radar providing the required pavement thickness data. The FWD data (i.e. deflections) were back-analysed in order to assess strains that would be utilised as output data in the process of developing the ANN model. A paper exercise demonstrates how the developed ANN model combined with the suggested conceptual approach for characterising pavement structural condition with regard to strain assessment could make provisions for pavement management activities, categorising network pavement sections according to the need for maintenance or rehabilitation. Preliminary results indicate that the ANN technique could help assist policy decision makers in deriving optimum strategies for the planning of pavement infrastructure maintenance. 相似文献
6.
Michael N. Kalochristianakis Fotis Georgatos Vasilis Gkamas Giannis Kouretis Emmanouel Varvarigos 《Journal of Grid Computing》2012,10(2):237-248
A determinant factor for the introduction of grid technologies in production domains of scale can be the design of easy, fast
and, from an operational point of view, realizable deployment procedures. Remote system management technologies, typically
used to monitor and manage IT environments, are designed to offer remote software installation functionality that exhibits
the aforementioned characteristics; however, previous work has shown that even valuable systems can fail to perform in heterogeneous,
geographically distributed environments, especially if they are maintained by organizations affiliated to the public sector.
The deployment of grid technologies throughout the Greek School Network can be achieved by combining OpenRSM, a novel open
source solution capable to support usable, configurable, infrastructure management use cases in heterogeneous environments
and LiveWN, a grid scavenging solution that integrates live technologies with gLite grids. 相似文献
7.
Evdokia K. Mitsou Niki Panopoulou Katja Turunen Vasilis Spiliotis Adamantini Kyriacou 《Food research international (Ottawa, Ont.)》2010,43(4):1086-1092
This randomised, double-blinded, placebo-controlled clinical study aimed to evaluate the in vivo prebiotic potential of barley β-glucan. Fifty-two healthy volunteers aged 39–70 years were randomly assigned to consume daily a cake containing 0.75 g of barley β-glucan or a placebo for 30 d. Stool samples were collected before, during and 2 weeks after the intervention for bacterial enumeration. Gastrointestinal side effects were recorded during the treatment period. In older subjects (?50 years old), barley β-glucan induced a strong bifidogenic effect and an increase of bifidobacteria into traceable range in cases of no detectable baseline levels. A concurrent significant increase in bacteroides was also observed in this age group. Ingestion of the experimental food resulted in no undesirable gastrointestinal side effects in older subjects. We concluded that the daily intake of a cake containing barley β-glucan is well-tolerated and demonstrated significant bifidogenic properties in older healthy volunteers consuming their usual diets. 相似文献
8.
Angelos Lenis Vasilis Merekoulias Vasilis Maglaris 《Journal of Network and Systems Management》2010,18(4):374-394
A challenge in network management and control is the ability to account for multi-domain requirements in the network planning
process. Especially in Connection Oriented Networks where multi-domain path finding is a critical issue, networks need to
be designed in such a manner as to restrict the possibility of erroneous inter-domain path selection. In this paper we propose
per-domain topology design considerations that would leverage accurate disjoint path computations in a multi-domain environment, covering requirements of end-to-end path resiliency. In multi-domain environments
state information between domains is heavily aggregated, hiding internal topology details dictated by scalability concerns,
but also by restrictive domain administration policies for privacy, and security. Disjoint path finding is strongly affected
by the aggregation techniques, since they do not provide information on path overlap. To handle this issue we introduce a
metric, the Overlap Factor (OF), that quantifies path overlap in domains. The OF can be passed as an additional parameter of the inter-domain information exchange model to evaluate disjoint end-to-end paths.
Alternatively, if domains were appropriately designed, this additional parameter might not be needed in evaluating resilient
pairs of inter-domain paths. We based our recommended topology design algorithm on exploiting locally known OF values within the context of Genetic Algorithms. Extensive simulations confirm that domains designed using our proposed algorithm,
result into accurate multi-domain disjoint path identification, with a high success ratio compared to networks that are designed
without inter-domain considerations. 相似文献
9.
Dimosthenis Sokaras Euthimios BistekosLambros Georgiou Joseph Salomon Mladen BogovacEleni Aloupi-Siotis Vasilis PaschalisIoanna Aslani Sofia KarabagiaAnastasios Lagoyannis Sotirios HarissopulosVasiliki Kantarelou Andreas-Germanos Karydas 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(5):519-527
At the 5.5 MV Tandem VdG accelerator of the Institute of Nuclear Physics of N.C.S.R. “Demokritos”, Athens, Greece, an external ion-beam set-up has been recently developed and installed. The aim of this development was to integrate the analytical capabilities of the PIXE, RBS and PIGE ion beam techniques in one experimental set-up, so that to attain a complete elemental and near surface structural characterization of samples in an almost non-destructive way and without any limitation concerning their size or conductive state. A careful 3D mechanical drawing optimized the set-up experimental parameters achieving probe dimensions at the millimeter range (1 mm2) and fulfilling the special requirements imposed for optimum performance of the aforementioned techniques, including the possibility to use heavier, than protons, ion beams. For the digital pulse processing of the X-ray, γ-ray and charged particle detector signals, novel hardware and software tools were developed based on a custom FPGA configuration.The first applications were focused in the quality control of materials that have been intentionally contaminated with a particular tracer-element (“tagged” materials). The tagged materials which were developed and tested are technologically authentic replicas of ancient attic ceramics with black glazed decoration. Analytical diagnostic studies were carried out for a few representative paintings of contemporary Greek painters in order to identify and document materials/pigments and techniques and eventually to prevent trade of fakes. Finally, ancient glass beads were also examined with respect to the sodium concentration and its in-depth homogeneity. 相似文献
10.
Giuseppe BattistoniFrancesco Broggi Markus BruggerMauro Campanella Massimo CarboniAnton Empl Alberto FassòEttore Gadioli Francesco CeruttiAlfredo Ferrari Anna FerrariMatthias Lantz Andrea MairaniM. Margiotta Cristina MoroneSilvia Muraro Katia ParodiVincenzo Patera Mauricio PelliccioniLarry Pinsky Johannes RanftStefan Roesler Sofia RolletPaola R. Sala Mario SantanaLucia Sarchiapone Massimiliano SioliGeorge Smirnov Florian SommererChristian Theis Stefania TrovatiR. Villari Heinz VinckeHelmut Vincke Vasilis Vlachoudis Joachim VollaireNeil Zapp 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2011,269(24):2850-2856