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排序方式: 共有1029条查询结果,搜索用时 15 毫秒
1.
Habibeh Haddad Dabaghi Abdolmajid Bayandori Moghaddam Mahmood Kazemzad Rassoul Dinarvand Fezze Aryanasab Mohammad Reza Nabid 《Journal of Applied Electrochemistry》2008,38(3):409-413
Electrochemical treatment processes can significantly contribute to the protection of the environment through the minimization
of waste and toxic materials in effluents. From a pharmaceutical point of view and due to the existing resemblance between
the electrochemical and biological reactions, it can be assumed that the oxidation mechanisms on the electrode and in the
body share similar principles. In this paper, the application of electrochemical studies in the design of an environmentally
friendly method was delineated for the new hydrocaffeic acid (HCA, 3,4-dihydroxy hydrocinnamic acid) derivatives synthesis
at carbon electrodes in an undivided cell. In this cell, the EC mechanism reaction was involved, comprising two steps alternatively;
(1) electrochemical oxidation and (2) chemical reaction. In particular, the electro-organic reactions of HCA, an important
biological molecule, were studied in a water–acetonitrile (90:10 v/v) mixture in the presence of benzenesulfinic acid (3) and p-toluenesulfinic acid (4). The research included the use of a variety of experimental techniques, such as cyclic voltammetry, controlled-potential
electrolysis and product spectroscopic identification. 相似文献
2.
The objective of this paper is to propose an architecture for aCAble TeleVision (CATV) network, capable of supporting two-way transmission. This evolution is necessary for the survival of the CATV industry in an era of deregulation and of the development of the B-ISDN by the telecommunications companies. A communication transactional service is then considered and performance analysis is done under realistic assumptions. 相似文献
3.
Algorithm for Increasing the Speed of Evolutionary Optimization and its Accuracy in Multi-objective Problems 总被引:3,自引:2,他引:1
Optimization algorithms are important tools for the solution of combinatorial management problems. Nowadays, many of those problems are addressed by using evolutionary algorithms (EAs) that move toward a near-optimal solution by repetitive simulations. Sometimes, such extensive simulations are not possible or are costly and time-consuming. Thus, in this study a method based on artificial neural networks (ANN) is proposed to reduce the number of simulations required in EAs. Specifically, an ANN simulator is used to reduce the number of simulations by the main simulator. The ANN is trained and updated only for required areas in the decision space. Performance of the proposed method is examined by integrating it with the non-dominated sorting genetic algorithm (NSGAII) in multi-objective problems. In terms of density and optimality of the Pareto front, the hybrid NSGAII-ANN is able to extract the Pareto front with much less simulation time compared to the sole use of the NSGAII algorithm. The proposed NSGAII-ANN methodology was examined using three standard test problems (FON, KUR, and ZDT1) and one real-world problem. The latter addresses the operation of a reservoir with two objectives (meeting demand and flood control). Thus, based on this study, use of the NSGAII-ANN integrative algorithm in problems with time-consuming simulators reduces the required time for optimization up to 50 times. Results of the real-world problem, despite lower computational-time requirements, show a performance similar to that achieved in the aforementioned test problems. 相似文献
4.
5.
Kapila V. Haddad W.M. Erwin R.S. Bernstein D.S. 《Automatic Control, IEEE Transactions on》1998,43(7):1003-1007
Parameterized Lyapunov bounds and shifted quadratic guaranteed cost bounds are merged to develop shifted parameter-dependent quadratic cost bounds for robust stability and robust performance. Robust fixed-order (i.e., full- and reduced-order) controllers are developed based on new shifted parameter-dependent bounding functions. A numerical example is presented to demonstrate the effectiveness of the proposed approach 相似文献
6.
Ordered binary decision diagrams (OBDDs) are a very popular graph representation for Boolean functions. They can be viewed as finite automata recognizing sets of strings of a fixed length, where the letters of the input strings are read at most once in a predefined ordering. The string matching problem with string w as pattern, consists of determining, given an input string, whether or not it contains w as substring. We show that for a fraction of orderings tending to 1 when n increases arbitrarily, the minimal size of an OBDD solving the string matching problem for strings of length n has a growth which is an exponential in n. 相似文献
7.
R. Spitzner G. Dill W. Schroth H. Hennig K. M. Jamil 《Advanced Synthesis \u0026amp; Catalysis》1976,318(2):298-312
Preparation and Coordination Behaviour of 2-Acylmethylene-thiazolidines The reaction of 2,2-dichlorovinyl ketones with 2-aminoethanethiol in different solvents is described. The 2-acylmethylene-thiazolidines as the main products from this reaction are studied in view of their coordination tendency to divalent metal ions. The prepared neutral chelates with Cu2+, Ni2+, Co2+, Pd2+, Zn2+ have [N2O2] coordination, elucidated by analytical, spectroscopical and magnetochemical methods. 相似文献
8.
Wei Gao Mohammad Reza Farahani Muhammad K. Jamil Muhammad K. Siddiqui Hafiz Muhammad Afzal Siddiqui Muhammad Imran 《Petroleum Science and Technology》2017,35(2):183-189
Different approaches have been used to convert the waste materials into a clean syngas or other chemicals such as methanol. Among them, pyrolysis is a good candidate to produce the synthesis gas and volatile matters for industrial and refinery applications. In this work, we studied the kinetic and chemical behavior of three Iranian waste oils through a kinetic model and an experimental study. The experiments carried out in a micro-FB reactor, which is a good option for low emissions. Results showed that the reaction temperature and reaction rate are two of the most important factors for maximum conversion level of fuel. Results also showed an optimum value for reaction rate. The modeling results validated against the experimental measurements and found to be in good agreements. 相似文献
9.
Adaptive median filters: new algorithms and results 总被引:39,自引:0,他引:39
Based on two types of image models corrupted by impulse noise, we propose two new algorithms for adaptive median filters. They have variable window size for removal of impulses while preserving sharpness. The first one, called the ranked-order based adaptive median filter (RAMF), is based on a test for the presence of impulses in the center pixel itself followed by a test for the presence of residual impulses in the median filter output. The second one, called the impulse size based adaptive median filter (SAMF), is based on the detection of the size of the impulse noise. It is shown that the RAMF is superior to the nonlinear mean L(p) filter in removing positive and negative impulses while simultaneously preserving sharpness; the SAMF is superior to Lin's (1988) adaptive scheme because it is simpler with better performance in removing the high density impulsive noise as well as nonimpulsive noise and in preserving the fine details. Simulations on standard images confirm that these algorithms are superior to standard median filters. 相似文献
10.
Chan H.L. Mohan S. Mazumder P. Haddad G.I. 《Solid-State Circuits, IEEE Journal of》1996,31(8):1151-1156
Quantum electronic devices with negative differential resistance (NDR) characteristics have been used to design compact multiplexers. These multiplexers may be used either as analog multiplexers where the signal on a single select line selects one out of four analog inputs, or as four-valued logic multiplexers where the select line and the input lines represent one of four quantized signal values and the output line corresponds to the selected input. Any four-valued logic function can be implemented using only four-valued multiplexers (also known as T-gates), and this T-gate uses just 13 devices (transistors) as compared to 44 devices in CMOS. The design of the T-gate was done using a combination of resonant tunneling diodes (RTD's) and heterojunction bipolar transistors (HBT's) with the folded I-V characteristic (NDR characteristic) of the RTD's providing the compact logic implementation and the HBT's providing the gain and isolation. The application of the same design principles to the design of T-gates using other NDR devices such as resonant tunneling hot electron transistors (RHET's) and resonant tunneling bipolar transistors (RTBT's) is also demonstrated 相似文献