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121.
Firouzeh Nemati Ali Ghorbani Gharjeh Ghiyaei Behrouz Notash Mojtaba Hajiloo Shayegan Vahid Amani 《Tetrahedron letters》2014
An efficient route for the synthesis of gem-bis(dithiocarbamate) derivatives is developed using dithiocarbamic acid salts generated from primary aliphatic amines and CS2. The method offers high yields, employs mild reaction conditions, and demonstrates excellent functional group compatibility. The structures of the products were confirmed spectroscopically and by X-ray analysis. 相似文献
122.
123.
Asad Asadujjaman Vahid Ahmadi Antoine Michel Claude Franc Annabelle Bertin 《Journal of polymer science. Part A, Polymer chemistry》2019,57(19):2064-2073
A novel copolymer based on supramolecular motif 2,6‐diaminopyridine and water‐soluble acrylamide, poly[N‐(6‐acetamidopyridin‐2‐yl) acrylamide‐co‐acrylamide], was synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization with various monomer compositions. The thermoresponsive behavior of the copolymers was studied by turbidimetry and dynamic light scattering (DLS). The obtained copolymers showed an upper critical solution temperature (UCST)‐type phase transition behavior in water and electrolyte solution. The phase transition temperature was found to increase with decreasing amount of acrylamide in the copolymer and increasing concentration of the solution. Furthermore, the phase transition temperature varied in aqueous solutions of electrolytes according to the nature and concentration of the electrolyte in accordance with the Hoffmeister series. A dramatic solvent isotope effect on the transition temperature was observed in this study, as the transition temperature was almost 10–12 °C higher in D2O than in H2O at the same concentration and acrylamide composition. The size of the aggregates below the transition temperature was larger in D2O compared to that in H2O that can be explained by deuterium isotope effect. The thermoresponsive behavior of the copolymers was also investigated in different cell medium and found to be exhibited UCST‐type phase transition behavior in different cell medium. Such behavior of the copolymers can be useful in many applications including biomedical, microfluidics, optical materials, and in drug delivery. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2064–2073 相似文献
124.
In this paper, a multi-objective robust tracking problem for nonlinear time-invariant systems with known time delay in state vector and control input is discussed. An augmented integral error is included in the tracking performance index which eliminates the effect of deterministic constant disturbances in the tracking problem. Uncertainties are considered as a nonlinear additive term in the problem. The discretized complete Lyapunov–Krasovskii functional (LKF) is used to formulate the robust resilient tracker with general quadratic performance. This approach yields much less conservatism than the conventional simple LKF design methods, and still allows writing both LKF and LKF derivative conditions in the form of linear matrix inequalities. Two comparative examples are given to illustrate the effectiveness of the proposed design method. 相似文献
125.
This paper proposes a new simple precoding solution based on the Gram–Schmidt orthonormalization to be used at the relay station of a multirelay wireless networks where the different mobile stations belong to the same network, in order to mitigate the multiuser interference at each mobile station. The strength of this method is that it only requires the knowledge of all channel impulse responses from a given relay to all the mobile stations. In other words, to compute its precoding vectors, each relay does not need to know the channel impulse responses of the channels of other relays. Unlike the centralized reference method where each mobile station benefits from the same diversity gain, using this algorithm, some mobile stations will improve their diversity gain at the cost of a loss in the diversity gain of other users. This constitutes a simple solution to supply different qualities of service in the case of a multiservices network. Furthermore, this work proposes an optimized power allocation between the relays. Analytical and accurate performance analyses for the different studied contexts are provided. 相似文献
126.
A gradient-based alternating minimization approach for optimization of the measurement matrix in compressive sensing 总被引:2,自引:0,他引:2
In this paper the problem of optimization of the measurement matrix in compressive (also called compressed) sensing framework is addressed. In compressed sensing a measurement matrix that has a small coherence with the sparsifying dictionary (or basis) is of interest. Random measurement matrices have been used so far since they present small coherence with almost any sparsifying dictionary. However, it has been recently shown that optimizing the measurement matrix toward decreasing the coherence is possible and can improve the performance. Based on this conclusion, we propose here an alternating minimization approach for this purpose which is a variant of Grassmannian frame design modified by a gradient-based technique. The objective is to optimize an initially random measurement matrix to a matrix which presents a smaller coherence than the initial one. We established several experiments to measure the performance of the proposed method and compare it with those of the existing approaches. The results are encouraging and indicate improved reconstruction quality, when utilizing the proposed method. 相似文献
127.
Given the performance and reliability limits of conventional copper interconnects in the tens of nanometer regime, carbon-nanotube (CNT) based interconnects emerge as a potential reliable alternative for future high performance VLSI industry. In this paper, we present an accurate thermally-aware model for single-walled carbon-nanotube (SWCNT) based interconnects. Our thermally-aware model is an integration of temperature-dependent electrical parasitics model and thermal equivalent circuit that captures both self-heating and heat conduction phenomena. We verify the accuracy of our electro-thermal model against recently reported experimental measurements. By leveraging the presented electro-thermal model, we present a simulation platform to estimate the performance of SWCNT-based interconnects under different temperature conditions. Our thermally-aware model achieves improvement in the delay estimation accuracy of about 51.3% on average. Based on our simulation results, SWCNT-based interconnects offer more than 5×reduction in delay at dimensions of about 10-20 nm for 27- 127 °C temperature range. 相似文献
128.
Arabali Vahid Karimi-Maleh Hassan Beitollahi Hadi Moradi Reza Ebrahimi Mahmoud Ahmar Hamid 《Ionics》2015,21(4):1153-1161
Ionics - In this study, a carbon paste electrode (CPE) was chemically modified with Pt/carbon nanotubes (CNTs) nanocomposite and 8,9-dihydroxy-7-methyl-12H-benzothiazolo [2,3-b] quinazolin-12-one... 相似文献
129.
130.
We investigate the coupling of a single molecule to a single spherical gold nanoparticle acting as a nanoantenna. Using scanning probe technology, we position the particle in front of the molecule with nanometer accuracy and measure a strong enhancement of more than 20 times in the fluorescence intensity simultaneous to a 20-fold shortening of the excited state lifetime. Comparisons with three-dimensional calculations guide us to decipher the contributions of the excitation enhancement, spontaneous emission modification, and quenching. Furthermore, we provide direct evidence for the role of the particle plasmon resonance in the molecular excitation and emission processes. 相似文献