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61.
This paper presents a novel low-power majority function-based 1-bit full adder that uses MOS capacitors (MOSCAP) in its structure. It can work reliably at low supply voltage. In this design, the time-consuming XOR gates are eliminated. The circuits being studied are optimized for energy efficiency at 0.18-μm CMOS process technology. The adder cell is compared with seven widely used adders based on power consumption, speed, power-delay product (PDP) and area efficiency. Intensive simulation runs on a Cadence environment and HSPICE show that the new adder has more than 11% in power savings over a conventional 28-transistor CMOS adder. In addition, it consumes 30% less power than transmission function adder (TFA) and is 1.11 times faster. 相似文献
62.
Among various speech enhancement methods, two-microphone noise reduction systems are utilized for their low cost implementation and acceptable performance. Coherence-based methods are well known as efficient two-microphone noise reduction techniques. These techniques, however, do not work well when the received noise signals are correlated. Coherence-based methods can be improved when the cross power spectral density (CPSD) of input noises is available. In this paper, we propose a new method for estimating noise CPSD based on the assumption of a diffuse noise field. With this assumption, we estimate the noise CPSD using phase information. Then, the estimated noise CPSD is used to calculate a coherence-based gain filter which is then employed to enhance noisy signals. We compare the proposed phase-based noise CPSD estimation with a noise CPSD estimation technique based on a voice activity detector (VAD), both of which are herein separately employed in a two-microphone speech enhancement configuration. The comparison shows that the two-microphone speech enhancement scheme utilizing the proposed noise CPSD estimation technique outperforms the enhancement system using the VAD-based noise CPSD estimation. 相似文献
63.
In this study, a soft method is proposed to calculate concentration and spectral profiles for the two‐way spectral data from dissociation equilibria of polyprotic acids (HnA). This method has four main distinct steps: (i) a fixed size moving window evolving factor analysis (FSMWEFA) was used to identify the local rank map, (ii) WFA was applied to calculate the concentration profiles of HnA and An− (selection of the window for application of WFA was performed using EFA), (iii) PVA was used to calculate Hn − 1A to HA spectral profiles, and (iv) a symmetry constraint, in addition to the non‐negativity constraint, was utilized to obtain the unique concentration and spectral profiles from different acceptable sets of profiles. In the absence of any selective region in the spectral data, the proposed soft method resulted in unique solution without rotational ambiguity. This study is the first application of symmetry constraint on concentration profiles. The rotational ambiguity drastically decreased on considering the constraint of symmetry of the Hn − 1A and HA concentration profiles, in addition to non‐negativity of profiles. Simulated examples were used to confirm these approaches. Effect of closeness of dissociation constants on the estimated values of constants was investigated. The results showed that when the difference between pKa values is more than 1.2, the obtained errors in the estimation of pKa values are less than about 6.5%. The considered real data were from pH‐metric titration of fluorescein. The obtained spectral and concentration profiles and the estimated pKa values for fluorescein were in good agreement with the previously reported data. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
64.
A partial second-order subdifferential is defined here for extended real valued functions of two variables corresponding to its variables through coderivatives of first-order partial subdifferential mappings. In addition, some rules are presented to calculate these second-order structures along with defining some conditions to insure the equality \(\partial ^2_{yx}\) and \(\partial ^2_{xy}\). Moreover, as an application, some conditions are stated which show the relation between local minimum of a function and positiveness of principal minors of its hessian matrix. 相似文献
65.
A. Yousfia S. Fréour F. Jacquemin M. Rahmani H. Osmani R. Guillén 《Mechanics of Composite Materials》2010,46(1):101-112
The mechanical behavior of carbon-fiber-reinforced polymer matrix composites having undergone a thermo-oxidation process is
studied. The purpose is to perform a multiscale analysis of the consequences of oxidation on the intrinsic mechanical properties
of the external composite ply and on the internal mechanical states experienced by the structure under mechanical loads. The
effective mechanical properties of oxidized composite plies are determined according to the Eshelby–Kr?ner self-consistent
homogenization procedure, depending on evolution of the oxidation process. The results obtained are compared with estimates
found by the finite-element method. The macroscopic mechanical states are calculated for a unidirectional composite and laminates.
The macroscopic stresses in each ply of the structure are determined by the classical lamination theory and the finite-element
method, whereas the local stresses in the carbon fiber and epoxy matrix are calculated by using an analytical stress concentration
relation. 相似文献
66.
Ali Darehkordi Maryam Hosseini Fariba Rahmani 《Journal of heterocyclic chemistry》2019,56(4):1306-1311
Syntheses of fused heterobicyclic systems containing 1,2,4‐triazolopyridinone moieties were accomplished by heterocyclization of 1,6‐diamino‐2‐oxo‐4‐phenyl‐1,2‐dihydropyridine‐3,5‐dicarbonitriles and ninhydrin in ethanol and in the presence of boric acid as a catalyst in 30 min at room temperature. All compounds have been screened for their photophysical properties. Results showed that all compounds exhibit near infrared emissions at 876 nm. 相似文献
67.
A La3+ doped Co3O4 nanocube modified graphite screen-printed electrode (La3+-doped Co3O4 nanocube/SPE) was prepared and utilized for the sensitive voltammetric determination of bisphenol A. In comparison with an unmodified electrode, the presence of the La3+ doped Co3O4 nanocubes caused a significant enhancement in the peak current. Differential pulse voltammetry (DPV), cyclic voltammetry (CV), and chronoamperometry approaches were utilized as diagnostic methods. The modified SPE was used to determine bisphenol A concentrations in the range from 0.5 to 900.0?μM with a limit of detection equal to 6.1?×?10?8 M. Real samples were effectively analyzed with the modified electrode. 相似文献
68.
Russian Journal of Electrochemistry - Lead dioxide was extracted from used batteries, and used to synthesize the following intermediate oxides by heating at different temperatures: Pb12O19,... 相似文献
69.
New hyperbranched hydrophobic cross‐linkers with peripheral azide groups were synthesized as follows: First, star‐shaped polycaprolactones (sPCL) were synthesized by ring‐opening polymerization of caprolactone in the presence of pentaerythritol and tin (II) octoate. In the next step, sequential acrylation, Micheal addition, tosylation, and azidation by acryloyl chloride, diethanol amine, tosyl chloride, and sodium azide were respectively exploited to synthesize azide‐functionalized hyperbranched star‐shaped polycaprolactones which were named sPCL‐acrylate‐diethanolamine‐azide (sPCL‐AC‐DEA‐N3) and sPCL‐acrylate‐diethanolamine‐acrylate‐diethanolamine‐azide (sPCL‐AC‐DEA‐AC‐N3). All steps were thoroughly characterized by FT‐IR and 1H NMR spectroscopy. The GPC analysis showed that the molecular weight of sPCL increased after two azide functionalizations. Amphiphilic hydrogels based on sPCL‐AC‐DEA‐N3 (Mn = 8130 g/mol) and sPCL‐AC‐DEA‐AC‐N3 (Mn = 10112 g/mol) with linear alkyne‐terminated polyethylene glycols (PEG) (Mn = 2000, 4000, and 6000 g/mol) were synthesized through click coupling between azide and alkyne groups. In both hydrogels, the swelling ratio increased by increasing the molecular weight of PEG. The obtained results showed that the branching of the cross‐linker, significantly affected the swelling ratio of hydrogels. For instance, the swelling ratio of sPCL‐AC‐DEA‐AC‐N3 and PEG‐6000 (Q = 900) was higher than sPCL‐AC‐DEA‐N3 and PEG‐6000 (Q = 600). Despite the high cross‐linking density of sPCL‐AC‐DEA‐AC‐DEA‐N3–based hydrogels, the amount of released theophylline was higher than sPCL‐AC‐DEA‐N3–based hydrogels, due to the high content of PEG in these hydrogels. 相似文献
70.
Moutab Sahihazar Milad Ahmadi Mohammad Taghi Nouri Mina Rahmani Meisam 《Journal of Solid State Electrochemistry》2019,23(6):1641-1650
Journal of Solid State Electrochemistry - Nanostructured carbon material (NSCM) based chemiresistive sensors are popular for sensing different analytes because of their high sensitivity, low cost,... 相似文献