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1.
G. Vourlias N. Pistofidis D. Chaliambalias K. Chrissafis El. Pavlidou G. Stergioudis 《Journal of Thermal Analysis and Calorimetry》2007,87(2):401-409
Zinc coatings on ferrous substrates are possible to be applied with
thermal spraying. In the present work the corrosion behavior of zinc thermal
sprayed coatings deposited on low carbon steel St-37 was examined in a simulated
marine atmosphere (salt spray chamber-SSC) and in a dry atmosphere at elevated
temperature (400°C). The corrosion progress was examined by means of optical
microscopy, scanning electron microscopy, X-ray diffraction and thermogravimetric
analysis. From this investigation it was deduced that in the SSC the coating
is uniformly corroded, while the main corrosion products are hydrated zinc
oxides and chlorides. By contrast at 400°C only a thin, compact and continuous
film of ZnO is formed on top of the coating, which remains adherent to the
ferrous substrate. 相似文献
2.
M. Anastasiou Th. Hasapis T. Zorba E. Pavlidou K. Chrissafis K. M. Paraskevopoulos 《Journal of Thermal Analysis and Calorimetry》2006,84(1):27-32
Historic
plasters from wall paintings of Byzantine and post-Byzantine churches situated
in the Balkan region were studied. All wall paintings were made with fresco
technique and are dated from IX - XVI century. Plaster samples were followed
from room temperature to 1000°C by Thermogravimetric (TG) and Differential
Thermal Analysis (DTA), and one or two significant temperature regions, corresponding
to thermal decomposition mechanisms were observed. The analysis of the plaster
samples and the composition characterization was carried out using also, Fourier
Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM).
Although the main components are calcite and quartz (from sand) in different
proportions, there are differences between them such as the presence of gypsum
being either as a constituent element or due to environmental pollution. The
results are examined comparatively taking into account the creation time and
place of the paintings. 相似文献
3.
4.
E. Fluck C. M. E. Pavlidou R. Janoschek 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):469-474
Abstract Experimental findings as well as quantum chemical calculations indicate that the P4 molecule has a remarkably low nucleophilicity. The P4H+ ion is predicted to have a ‘proton at apex’ configuration whereas a proton in the centre seems to be metastable. The influence of d orbitals on the stability of P4 against 2 P2 and 1/2 P8, the photoelectron spectrum, and the valence electron density is discussed. 相似文献
5.
X. Liang F. L. C. Ong P. Pillai P. M. L. Chan V. Mancuso G. Koltsidas F. N. Pavlidou L. Caviglione E. Ferro A. Gotta H. Cruickshank S. Iyengar G. Fairhurst 《International Journal of Satellite Communications and Networking》2007,25(4):409-440
This is the second part of the tutorial paper following the previous tutorial paper describing enabling technologies in digital video broadcasting (DVB) system. The paper presents the current and future operational scenarios for DVB via satellite (DVB‐S) system. Review of the current state‐of‐the‐art technologies consisting of integration of broadband Internet and mobile communications and integration of broadband Internet and DVB are given. The future operational scenarios emphasize the fusion of DVB systems with other technologies in terms of network fusion and terminal fusion. For satellite service scenarios, it also takes into consideration mobility management and standard quality‐of‐service mechanism issues, such as integrated services and differentiated services. Several research directions for providing seamless services regardless of network, access technology and terminal in the fusion network are also highlighted in this paper. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
6.
Fotini-Niovi Pavlidou Marina Ruggieri Mario Gerla Ryu Miura 《Wireless Personal Communications》2004,28(2):161-162
Wireless Personal Communications - 相似文献
7.
Panagiotis I. Dallas Dr. Fotini-Niovi Pavlidou 《International Journal of Wireless Information Networks》1996,3(3):163-172
DS/CDMA noncoherentM-ary orthogonal signaling is presented in a hexagonal cell with three and six corner-based antennas. Multipath Rayleigh channel
with lognormal shadowing and perfect power control are assumed. The asynchronous case (uplink) is studied. Bit error rate
analysis is carried out to investigate the benefits of combining theM-ary orthogonal signaling and macrodiversity techniques either with uncorrelated or correlated base stations. Comparative
analysis between the one central antenna arrangement and the proposed one is presented. The results show that the combination
ofM-ary signaling with multiple corner-based antennas improves system performance especially in terms of accommodating more users
and supporting new services. The results also show that shadowing does not degrade system performance significantly. 相似文献
8.
9.
Wireless Local Area Networks have gained popularity at an unprecedented rate over the last few years. However, as the spectrum of applications they are called to support broadens, their inefficiency in meeting the diverse requirements of a wider range of applications becomes evident. Most existing access mechanisms cannot provide Quality-of-Service (QoS) assurances. Even those that are QoS aware can only provide relative service differentiation. In this work, we propose a dynamic priority medium access scheme to provide time-bounded services. By approximating an ideal Earliest Deadline First (EDF) scheduler, the proposed scheme can offer delay and delay jitter assurances while achieving high medium utilization. Analytical studies and simulation experiments document and confirm the positive characteristics of the proposed mechanism.
Orestis Tsigkas received his Diploma in electrical and computer engineering from the Aristotle University of Thessaloniki, Greece in 2002. He is currently working towards his Ph.D. degree in the same department. His research interests include medium access, as well as quality-of-service provisioning.
Fotini-Niovi Pavlidou received the Ph.D. degree in electrical engineering from the Aristotle University of Thessaloniki, Greece, in 1988 and the Diploma in mechanical-electrical engineering in 1979 from the same institution. She is currently a Professor at the Department of Electrical and Computer Engineering at the Aristotle University engaged in teaching for the under- and post-graduate program in the areas of mobile communications and telecommunications networks. Her research interests are in the field of mobile and personal communications, satellite communications, multiple access systems, routing and traffic flow in networks and QoS studies for multimedia applications over the Internet. She is being involved with many national and international projects in these areas (Tempus, COST, Telematics,IST) and she has been chairing the European COST262 Action on “Spread Spectrum Systems and Techniques for Wired and Wireless Communications”. She has served as member of the TPC in many IEEE/IEE conferences and she has organized/chaired some conferences like, the “IST Mobile Summit 2002”, the 6th “International Symposium on Power Lines Communications-ISPLC2002”, the “International Conference on Communications-ICT1998” etc. She is a permanent reviewer for many IEEE/IEE journals. She has published about 80 papers in refereed journals and conferences. She has served as guest-editor on special issues as: “Mobile Ad Hoc Networks (MANETs): Standards, Research, Applications” in the International Journal of Wireless Information Networks and “Power Line Communications and Applications” in the International Journal on Communications Systems. She is a senior member of IEEE, currently chairing the joint IEEE VT&AES Chapter in Greece. 相似文献
10.
Medium access represents one of the most critical building blocks regarding the performance of a wireless LAN. In this letter, we compare the performance of two well-known medium access control protocols specifically developed for the wireless environment, EDCF and EY-NPMA. To our knowledge, it is the first time that these two quality-of-service (QoS) aware medium access schemes are compared. Furthermore, we propose a novel scheme for medium access based on EY-NPMA, that demonstrates reduced overhead compared to the base protocol and better utilization of the common medium. The conclusions of this paper are based on extensive simulation trials. 相似文献