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31.
A. Bouazra S. Abdi-Ben Nasrallah A. Poncet M. Said 《Materials Science in Semiconductor Processing》2006,9(6):989
Silicon-based devices are currently the most attractive group because they are functioning at room temperature and can be easily integrated into conventional silicon microelectronics. There are many models and simulation programs available to compute CV curves with quantum correction [Choi C-H, Wu Y, Goo JS, Yu Z, Dutton RW. IEEE Trans on Electron Devi 2000; 47(10): 1843; Croci S, Plossu C, Burignat S. J Mater Sci Mater Electron 2003; 14: 311; Soliman L, Duval E, Benzohra M, Lheurette E, Ketata K, Ketata M. Mater Sci Semicond Process 2001; 4: 163]. This work deals with the simulation of electron transfer through SiO2 barrier of metal–oxide–semiconductor structure (MOS). The carrier density is given by a self consistent resolution of Schrödinger and Poisson equations and then the MOS capacitance is deduced and compared with results available in literature. As it is well known, the MOS capacitance–voltage profiling provides a simple determination of structure parameters. The extracted tunnel oxide thickness and substrate doping are compared with those used in the simulation. For the purpose to investigate the electron tunnelling through the barrier, we have used the transfer matrix approach. Using I–V simulations, we have shown that the traps in SiO2 matrix have a drastic influence on electron tunnelling through the barrier. The trap-assisted contribution to the tunnelling current is included in many models [Maserjian J, Zamani N. J Appl Phys 1982; 53(1): 559; Houssa M, Stesmans A, Heyns MM. Semicond Sci Technol 2001; 16: 427; Aziz A, Kassmi K, Kassmi Ka, Olivie F. Semicond Sci Technol 2004; 19: 877; Wu You-Lin, Lin Shi-Tin. IEEE Trans Dev Mater Reliab 2006; 6(1): 75; Larcher L. IEEE Trans Electron Dev 2003; 50(5): 1246]; this is the basis for the interpretation of stress induced leakage current (SILC) and breakdown events. Memory effect becomes typical for this structure. We have studied the I–V dependence with trap parameters. 相似文献
32.
The use of FRP as reinforcement in concrete structures has been growing rapidly. A potential application of FRP reinforcement
is in reinforced concrete (RC) frames. However, due to FRP's predominantly elastic behaviour, FRP-RC members exhibit low ductility
and energy dissipation. Hybrid steel-FRP reinforcement can be a viable solution to the lack of ductility of FRP-RC members.
Using two layers of reinforcement in a section, FRP rebars can be placed in the outer layer and steel rebars in the inner
layer away from the effects of carbonation and chloride intrusion. Combined with the use of FRP stirrups, this approach can
enhance the corrosion resistance of RC members. However, current design standards and detailing criteria for FRP-RC structures
do not provide detailed seismic provisions. In particular, the design and detailing of beam-column joints is a key issue in
seismic design. During recent earthquakes, many structural collapses were initiated or caused by beam-column joint failures.
Thus, research is needed to gain a better understanding of the behaviour of FRP and hybrid FRP-steel-RC under seismic loading.
In this study, three full-scale beam-column joint specimens reinforced with steel, GFRP and a hybrid GFRP-steel configuration,
respectively were tested in order to investigate their performance in the event of an earthquake.
Résumé L'utilisation de barres en polymères renforcés de fibres (PRF) comme armature dans les structures en béton est en train d'augmenter rapidement. Une application prometteuse des armatures en PRF est dans les structures en cadres de béton armé à multi-étages. Cependant, à cause de leur comportement élastique, les membres renforcés avec des armatures en PRF démontrent une ductilité limitée et une faible capacité de dissipation d'énergie. Les systèmes hybrides (combinaison d'armatures en acier et en polymères renforcés de fibres de verre (PRFV) se présentent comme une solution pratique pour remédier aux inconvénients des systèmes renforcés uniquement avec PRFV. En utilisant deux couches d'armatures, les barres en PRFV peuvent être placées à l'extérieur et ceux en acier à l'intérieur, loin des effets de la carbonatation et l'intrusion des ions chlores. En plus, l'utilisation des étriers en PRFV peut améliorer la durabilité de ces structures. Cependant, les normes de conception actuelles pour PRF n'offrent pas assez de détails sur les provisions sismiques, en particulaier sur la conception des joints de poutres-colonnes. De récents tremblements de terre ont démontré sans équivoque que les joints de poutres-colonnes sont critiques pour assurer l'intégrité structurale. Alors, il est important d'étudier le comportement de tels assemblages utilisant des armatures en PRFV ou des armatures hybrides (acier-PRFV). Dans cette étude, trois assemblages poutrecolonne en grandeur nature renforcés avec des armatures en acier, PRFV, et hybride (acier-PRFV) ont été construits et testés sous charges cycliques pour examiner leur comportement durant des tremblements de terre.相似文献
33.
The use of FRP as reinforcement in concrete structures has been growing rapidly due to its advantages over conventional steel reinforcement (e.g., corrosion resistance, light weight, magnetic neutrality). A potential application of FRP reinforcement is in structural concrete frames. However, current seismic design standards and detailing criteria for beam-column joints were established for steel reinforcement and may be unsuitable for FRP reinforcement due to its different mechanical properties. During recent earthquakes, many structural collapses were initiated or caused by beam-column joint failures. Since there are no detailed specifications for the application of FRP reinforcement in seismic zones, research is needed to gain a better understanding of the behaviour of FRP-reinforced concrete under seismic loading. In this study, two full-scale beam-column joint specimens reinforced with steel and GFRP, respectively, were tested in order to investigate their performance in the event of an earthquake. The control steel-reinforced specimen is detailed according to the Canadian Code (CSA A23.3-94) recommendations. The GFRP-reinforced specimen is detailed in a similar scheme but using a GFRP grid. The behaviour of the two specimens under reversed cyclic loading, their load-storey drift envelope relationship and energy dissipation ability were compared. The GFRP-reinforced specimen showed a predominantly elastic behaviour up to failure. While its energy dissipation was low, its performance was acceptable in terms of total storey drift demand. 相似文献
34.
Mohamad Maatouk Ahmad Ibrahim Lucile Pinault Nicholas Armstrong Said Azza Jean-Marc Rolain Fadi Bittar Didier Raoult 《International journal of molecular sciences》2022,23(10)
The increased exploitation of microbial sequencing methods has shed light on the high diversity of new microorganisms named Candidate Phyla Radiation (CPR). CPR are mainly detected via 16S rRNA/metabarcoding analyses or metagenomics and are found to be abundant in all environments and present in different human microbiomes. These microbes, characterized by their symbiotic/epiparasitic lifestyle with bacteria, are directly exposed to competition with other microorganisms sharing the same ecological niche. Recently, a rich repertoire of enzymes with antibiotic resistance activity has been found in CPR genomes by using an in silico adapted screening strategy. This reservoir has shown a high prevalence of putative beta-lactamase-encoding genes. We expressed and purified five putative beta-lactamase sequences having the essential domains and functional motifs from class A and class B beta-lactamase. Their enzymatic activities were tested against various beta-lactam substrates using liquid chromatography-mass spectrometry (LC-MS) and showed some beta-lactamase activity even in the presence of a beta-lactamase inhibitor. In addition, ribonuclease activity was demonstrated against RNA that was not inhibited by sulbactam and EDTA. None of these proteins could degrade single- and double-stranded-DNA. This study is the first to express and test putative CPR beta-lactamase protein sequences in vitro. Our findings highlight that the reduced genomes of CPR members harbor sequences encoding for beta-lactamases known to be multifunction hydrolase enzymes. 相似文献
35.
Alawi Alqushaibi Mohd Hilmi Hasan Said Jadid Abdulkadir Amgad Muneer Mohammed Gamal Qasem Al-Tashi Shakirah Mohd Taib Hitham Alhussian 《计算机、材料和连续体(英文)》2023,75(2):3223-3238
Diabetes mellitus is a long-term condition characterized by hyperglycemia. It could lead to plenty of difficulties. According to rising morbidity in recent years, the world’s diabetic patients will exceed 642 million by 2040, implying that one out of every ten persons will be diabetic. There is no doubt that this startling figure requires immediate attention from industry and academia to promote innovation and growth in diabetes risk prediction to save individuals’ lives. Due to its rapid development, deep learning (DL) was used to predict numerous diseases. However, DL methods still suffer from their limited prediction performance due to the hyperparameters selection and parameters optimization. Therefore, the selection of hyper-parameters is critical in improving classification performance. This study presents Convolutional Neural Network (CNN) that has achieved remarkable results in many medical domains where the Bayesian optimization algorithm (BOA) has been employed for hyperparameters selection and parameters optimization. Two issues have been investigated and solved during the experiment to enhance the results. The first is the dataset class imbalance, which is solved using Synthetic Minority Oversampling Technique (SMOTE) technique. The second issue is the model's poor performance, which has been solved using the Bayesian optimization algorithm. The findings indicate that the Bayesian based-CNN model superbases all the state-of-the-art models in the literature with an accuracy of 89.36%, F1-score of 0.88.6, and Matthews Correlation Coefficient (MCC) of 0.88.6. 相似文献
36.
Fahimeh Dehkhoda Javad Frounchi Said Al‐Sarawi 《International Journal of Circuit Theory and Applications》2014,42(8):858-869
A new integrated, low‐noise, low‐power, and area‐efficient multichannel receiver for magnetic resonance imaging (MRI) is described. The proposed receiver presents an alternative technique to overcome the use of multiple receiver front‐ends in parallel MRI. The receiver consists of three main stages: low‐noise pre‐amplifier, quadrature down‐converter, and a band pass filter (BPF). These components are used to receive the nuclear magnetic resonance signals from a 3 × 3 array of micro coils. These signals are combined using frequency domain multiplexing (FDM) method in the pre‐amplifier and BPF stages, then amplified and filtered to remove any out‐of‐band noise before providing it to an analog‐to‐digital converter at the low intermediate frequency stage. The receiver is designed using a 90 nm CMOS technology to operate at the main B0 magnetic field of 9.4 T, which corresponds to 400 MHz. The receiver has an input referred noise voltage of 1.1 nV/√Hz, a total voltage gain of 87 dB, a power consumption of 69 mA from a 1 V supply voltage, and an area of 305 µm × 530 µm including the reference current and bias voltage circuits. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
37.
Emad S. Hassan Xu Zhu Said E. El‐Khamy Moawad I. Dessouky Sami A. El‐Dolil Fathi E. Abd El‐Samie 《International Journal of Communication Systems》2011,24(1):1-13
In this paper, we study the performance of the continuous phase modulation (CPM)‐based orthogonal frequency division multiplexing (CPM‐OFDM) system. Also, we propose a CPM‐based single‐carrier frequency domain equalization (CPM‐SC‐FDE) structure for broadband wireless communication systems. The proposed structure combines the advantages of the low complexity of SC‐FDE, in addition to exploiting the channel frequency diversity and the power efficiency of CPM. Both the CPM‐OFDM system and the proposed system are implemented with FDE to avoid the complexity of the equalization. Two types of frequency domain equalizers are considered and compared for performance evaluation of both systems; the zero forcing (ZF) equalizer and the minimum mean square error (MMSE) equalizer. Simulation experiments are performed for a variety of multipath fading channels. Simulation results show that the performance of the CPM‐based systems with multipath fading is better than their performance with single path fading. The performance over a multipath channel is at least 5 and 12 dB better than the performance over a single path channel, for the CPM‐OFDM system and the proposed CPM‐SC‐FDE system, respectively. The results also show that, when CPM is utilized in SC‐FDE systems, they can outperform CPM‐OFDM systems by about 5 dB. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
38.
Isabelle Six Nicolas Guillaume Valentine Jacob Romuald Mentaverri Said Kamel Agns Boullier Michel Slama 《International journal of molecular sciences》2022,23(11)
The endothelium has a fundamental role in the cardiovascular complications of coronavirus disease 2019 (COVID-19). Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) particularly affects endothelial cells. The virus binds to the angiotensin-converting enzyme 2 (ACE-2) receptor (present on type 2 alveolar cells, bronchial epithelial cells, and endothelial cells), and induces a cytokine storm. The cytokines tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6 have particular effects on endothelial cells—leading to endothelial dysfunction, endothelial cell death, changes in tight junctions, and vascular hyperpermeability. Under normal conditions, apoptotic endothelial cells are removed into the bloodstream. During COVID-19, however, endothelial cells are detached more rapidly, and do not regenerate as effectively as usual. The loss of the endothelium on the luminal surface abolishes all of the vascular responses mediated by the endothelium and nitric oxide production in particular, which results in greater contractility. Moreover, circulating endothelial cells infected with SARS-CoV-2 act as vectors for viral dissemination by forming clusters that migrate into the circulation and reach distant organs. The cell clusters and the endothelial dysfunction might contribute to the various thromboembolic pathologies observed in COVID-19 by inducing the formation of intravascular microthrombi, as well as by triggering disseminated intravascular coagulation. Here, we review the contributions of endotheliopathy and endothelial-cell-derived extracellular vesicles to the pathogenesis of COVID-19, and discuss therapeutic strategies that target the endothelium in patients with COVID-19. 相似文献
39.
Recently multiserver queues with setup times have been extensively studied because they have applications in power-saving data centers. A challenging model is the M/M/c/Setup queue where a server is turned off when it is idle and is turned on if there are some waiting jobs. Recently, Gandhi et al. (in: Proceedings of the ACM SIGMETRICS, pp. 153–166, ACM, 2013; Queueing Syst. 77(2):177–209, 2014) obtain the generating function of the number of jobs in the system, as well as the Laplace transform of the response time using the recursive renewal reward approach and the distributional Little’s law (Keilson and Servi in Oper Res Lett 7(5):223– 227, 1988). In this paper, we derive exact solutions for the joint stationary queue length distribution of the same model using two alternative methodologies: generating function approach and matrix analytic method. The generating function approach yields exact closed form expressions for the joint stationary queue length distribution and the conditional decomposition formula. On the other hand, the matrix analytic approach leads to an exact recursive algorithm to calculate the joint stationary distribution and performance measures so as to provide some application insights. 相似文献
40.
Laith Mohammad Abualigah Ahamad Tajudin Khader Essam Said Hanandeh 《Applied Intelligence》2018,48(11):4047-4071
In this paper, a novel text clustering method, improved krill herd algorithm with a hybrid function, called MMKHA, is proposed as an efficient clustering way to obtain promising and precise results in this domain. Krill herd is a new swarm-based optimization algorithm that imitates the behavior of a group of live krill. The potential of this algorithm is high because it performs better than other optimization methods; it balances the process of exploration and exploitation by complementing the strength of local nearby searching and global wide-range searching. Text clustering is the process of grouping significant amounts of text documents into coherent clusters in which documents in the same cluster are relevant. For the purpose of the experiments, six versions are thoroughly investigated to determine the best version for solving the text clustering. Eight benchmark text datasets are used for the evaluation process available at the Laboratory of Computational Intelligence (LABIC). Seven evaluation measures are utilized to validate the proposed algorithms, namely, ASDC, accuracy, precision, recall, F-measure, purity, and entropy. The proposed algorithms are compared with the other successful algorithms published in the literature. The results proved that the proposed improved krill herd algorithm with hybrid function achieved almost all the best results for all datasets in comparison with the other comparative algorithms. 相似文献