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101.
The authors point out that the reliability and performance of electronic circuits are influenced by heat conduction in low-pressure chemical-vapor-deposited (LPCVD) silicon dioxide layers. Here, the effective thermal conductivity k eff for conduction normal to films of LPCVD silicon dioxide layers as a function of annealing temperature, as well as for films of thermal and SIMOX oxides, is measured. The LPCVD oxide thermal conductivity increases by 23% due to annealing at 1150°C. The conductivities k eff of LPCVD layers of thicknesses between 0.03 and 0.7 μm are higher than those reported previously for CVD layers, and vary between 50% and 90% of the conductivities of bulk fused silicon dioxide. The values of SIMOX and thermal oxide layers are within the experimental error of the values for bulk fused silicon dioxide 相似文献
102.
Nayfeh H.M. Leitz C.W. Pitera A.J. Fitzgerald E.A. Hoyt J.L. Antoniadis D.A. 《Electron Device Letters, IEEE》2003,24(4):248-250
In this letter, we investigate the dependence of electron inversion layer mobility on high-channel doping required for sub-50-nm MOSFETs in strained silicon (Si), and we compare it to co-processed unstrained Si. For high vertical effective electric field E/sub eff/, the electron mobility in strained Si displays universal behavior and shows enhancement of 1.5-1.7/spl times/ compared to unstrained Si. For low E/sub eff/, the mobility for strained Si devices decreases toward the unstrained Si data due to Coulomb scattering by channel dopants. 相似文献
103.
Ioannis Kousis Marina Laskari Vasileios Ntouros Margarita-Niki Assimakopoulos Joanna Romanowicz 《Energy Sources, Part B: Economics, Planning, and Policy》2020,15(2):113-135
ABSTRACT Existing research suggests that students are an under-reported and under-supported group of the population that frequently lives in fuel poverty. Furthermore, studies show that students do not realize that they live in fuel poor conditions and are rarely recognized as a group vulnerable to fuel poverty. The aim of the research presented in this paper is to understand, evaluate and consequently reveal the experiences of students living in the private-rentedd sector, quantify their possible exposure to fuel poverty, and to determine the impacts of this exposure on their well-being. Three thousand five hundred and twelve students from seven European countries participated in this research making it the largest study to date targeting this specific social group. Our results demonstrate that this group is vulnerable to fuel poverty and that their exposure to such conditions can have a detrimental effect on both their mental and physical health, as well as their social life. 相似文献
104.
105.
A Abrahim A Papa N Soultos I Ambrosiadis A Antoniadis 《Canadian Metallurgical Quarterly》1998,61(10):1378-1380
Sixty-five samples of traditionally made fresh sausages obtained from retail shops and butcher shops in northern Greece were screened for the presence of Salmonella spp. and Listeria spp. Salmonella spp. were found in 20% of the samples tested (54% Salmonella typhimurium and 46% Salmonella enteritidis). The prevalence of Listeria spp. in the samples was 26% (12% Listeria monocytogenes, 76% Listeria innocua, and 12% Listeria welshimeri). Nine of 13 Salmonella isolates were found to be resistant to ampicillin and 4 of 13 showed intermediate sensitivity; 1 of 13 was found to be resistant to chloramphenicol and 1 of 13 to tetracycline. Two strains of Salmonella typhimurum were multiresistant (resistant to ampicillin, chloramphenicol, and norfloxacin). All Listeria isolates were sensitive to the antibacterial agents tested that are commonly used for the treatment of human listeriosis. 相似文献
106.
Vasileios Theodorakopoulos Michael E. Woodward 《Multimedia Tools and Applications》2006,28(1):125-139
This paper presents a unique set of techniques to support reliable and efficient video transmission over mobile channels.
The transmission system is comprised of an M level Quadrature Amplitude Modulation (QAM) technique. A twin class uniform and non-uniform partitioned M-QAM system is used
to transport a compressed video bitstream which is partitioned to match the bit-error sensitivity of the transmitted symbol
in terms of mapping in the constellation diagram and picture quality. Video partitioning based on a separation of the Variable
Length Coded (VLC) Discrete Cosine Transforms (DCT) coefficients within each block is considered for constant bitrate transmission
(CBR). Various scenarios for splitting the bitstream are investigated and their results are compared and analysed thoroughly.
The performance of the transmission system is evaluated under Additive White Gaussian Noise (AWGN) conditions. The simulation
results showed that the video partition strategy results in a significantly higher quality of the reconstructed video data. 相似文献
107.
We have fabricated a SOI laterally diffused MOSFET that is designed for use in radio frequency power amplifiers for wireless system-on-a-chip applications. The device is fabricated on a thin-film SOI wafer using a process that is suitable for integration with SOI CMOS. An under-source body contact is implemented and both a high breakdown voltage and a high ft are attained. The device performance compares favorably with bulk silicon rf power MOSFETs. For a gate length of 0.7 μm the device ft is 14 GHz, fmax is 18 GHz, and the breakdown voltage approaches 25 V 相似文献
108.
George Tsakiris Nikos Kordalis Dimitris Tigkas Vasileios Tsakiris Harris Vangelis 《Water Resources Management》2016,30(15):5723-5735
Droughts can be considered as multidimensional hazardous phenomena characterised by three attributes: severity, duration and areal extent. Conventionally, drought events are assessed for their severity, using drought indices such as SPI (Standardised Precipitation Index), RDI (Reconnaissance Drought Index), PDSI (Palmer Drought Severity Index) and many others. This approach may be extended to incorporate the modelling of an additional dimension, the duration or the areal extent. Since the marginal distributions describing these dimensions of drought are often different, no simple mixed probability distribution can be used for the bivariate frequency analysis. The copula approach seems to be sufficiently general and suitable for this type of analysis. It is the aim of this paper to analyse droughts as two-dimensional phenomena, including drought severity and areal extent. In this paper, the Gumbel-Hougaard copula from the Archimedean family is used for this two-dimensional frequency analysis. Annual data on historical droughts from Eastern Crete are analysed for their severity and areal extent, producing copula-based probability distributions, incorporating Gumbel marginal probability functions. Useful conclusions are derived for estimating the «OR» return period of drought events related to both severity and areal extent. 相似文献
109.
Vasileios K. Sakarellos Charilaos Kourogiorgas Athanasios D. Panagopoulos 《Wireless Personal Communications》2014,79(2):1471-1481
Next generation communication networks incorporate Land Mobile Satellite (LMS) systems in order to provide greater areas of coverage and higher throughput for specific applications. Cooperation between satellite communication networks and terrestrial relays is or increasing the system’s performance and availability. In this paper, the outage performance of a cooperative hybrid satellite and terrestrial system configuration is analytically evaluated assuming that the satellite links suffer from shadowed Rician fading, while the terrestrial link suffers from the Nakagami-m fading. Two cooperative relaying strategies are examined and the final formulas for the calculation of the outage probability are given. Moreover, a block diagram for the generation of time series for the reliable simulations of the outage probability of the cooperative hybrid land mobile satellite systems is given. The theoretical results and the simulation results almost coincide. Moreover, extended numerical results investigate the impact, of different shadowing conditions and more generally of the satellite links elevation angles, on the overall cooperative LMS system performance. 相似文献
110.
One of the challenges in a military wireless sensor network is the determination of an information collection infrastructure which minimizes battery power consumption. The problem of determining the right information collection infrastructure can be viewed as a variation of the network design problem, with the additional constraints related to battery power minimization and redundancy. The problem in its generality is NP-hard and various heuristics have been developed over time to address various issues associated with it. In this paper, we propose a heuristic based on the mammalian circulatory system, which results in a better solution to the design problem than the state of the art alternatives. 相似文献