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Articles 5941 - 5970 of 10319
Full-Text Articles in Physical Sciences and Mathematics
Performance Evaluation Of A Fuzzy Variable Structure Satellite Attitude Controller Under Sensor Data Delay, Bi̇lgehan Erkal, Hüseyi̇n Demi̇rel
Performance Evaluation Of A Fuzzy Variable Structure Satellite Attitude Controller Under Sensor Data Delay, Bi̇lgehan Erkal, Hüseyi̇n Demi̇rel
Turkish Journal of Electrical Engineering and Computer Sciences
One of the main sources of uncertainties in controlling the attitude of a satellite is the time delays seen in sensor data. Although it is possible to process sensor data to correct the deficiencies caused by delays, it is more suitable to design the controller robust enough to handle uncertainties well. In this study, the attitude of a 3-degrees of freedom satellite model, incorporating uncertainties (both sensor data delay and actuator misplacements), is controlled using a suitably designed fuzzy variable structure controller (FVSC). The performance of the FVSC is evaluated and compared to that of other reference controllers [proportional-derivative (PD), …
An Efficient Approach To The Local Optimization Of Finite Electromagnetic Band-Gap Structures, David Duque, Vito Lancellotti, Bastiaan Pieter De Hon, Antonius Tijhuis
An Efficient Approach To The Local Optimization Of Finite Electromagnetic Band-Gap Structures, David Duque, Vito Lancellotti, Bastiaan Pieter De Hon, Antonius Tijhuis
Turkish Journal of Electrical Engineering and Computer Sciences
We propose a methodology based on linear embedding via Green's operators (LEGO) and the eigencurrent expansion method (EEM) to efficiently deal with and locally optimize 2-D electrically large electromagnetic band-gap (EBG) structures. In LEGO terminology, the composite EBG structure is broken up (diakopted) into constitutive elements called ``bricks'' that we characterize through scattering operators by invoking Love's equivalence principle, while, at the same time, the electromagnetic interaction among the bricks is captured by transfer operators. The resulting electromagnetic problem is then succinctly formulated through an integral equation involving the total inverse scattering operator S^{-1} of the structure. To perform local …
Design And Implementation Of An Observer Controller For A Buck Converter, Shenbaga Lakshmi, Sree Renga Raja
Design And Implementation Of An Observer Controller For A Buck Converter, Shenbaga Lakshmi, Sree Renga Raja
Turkish Journal of Electrical Engineering and Computer Sciences
An observer controller for a buck converter is presented. A state feedback gain matrix is derived in order to achieve the stability of the converter and to ensure the robustness of the controller. A load estimator is designed to estimate the unmeasurable variables and to obtain the zero output voltage error. A pulse-width modulation scheme is adopted to obtain the output voltage regulation. In order to improve the transitory response and dynamic constancy of the converter, the controller parameters are designed based on the current mode control. The design is evaluated and verified using MATLAB/Simulink. An experimental set-up is done …
Neuro-Fuzzy Network Approach For Modeling Submicron Mosfets: Application To Mosfet Subcircuit Simulation, Amirhossein Abdollahinohoji, Fardad Farokhi, Majid Zamani
Neuro-Fuzzy Network Approach For Modeling Submicron Mosfets: Application To Mosfet Subcircuit Simulation, Amirhossein Abdollahinohoji, Fardad Farokhi, Majid Zamani
Turkish Journal of Electrical Engineering and Computer Sciences
A neuro-fuzzy network approach is developed to model the nonlinear behavior of submicron metal-oxide semiconductor field-effect transistors (MOSFETs). The proposed model is trained and implemented as a MOSFET in a software environment. The training data are obtained through various simulations of a MOSFET Berkeley short channel insulated-gate field-effect transistor model 3 (BSIM3) in HSPICE, and the trained model is utilized to simulate the MOSFET device. The obtained result shows good and noticeable agreement between the numerical result of the original model in HSPICE and the neuro-fuzzy approach in the device and subcircuit modeling.
Removing Random-Valued Impulse Noise In Images Using A Neural Network Detector, İlke Türkmen
Removing Random-Valued Impulse Noise In Images Using A Neural Network Detector, İlke Türkmen
Turkish Journal of Electrical Engineering and Computer Sciences
This paper proposes a new method using an artificial neural network to remove random-valued impulse noise (RVIN) in images. The inputs of the neural model used to detect the RVIN are formed using basic and related gradient values. The detection of the noisy pixels is realized in 3 phases using the proposed neural detector. In order to obtain a more robust detector, 2 different networks, which are trained with an artificial training image corrupted with high and low clutter densities, are used. The extensive simulation results show that the proposed method is significantly better than the compared filters in terms …
An Urgent Precaution System To Detect Students At Risk Of Substance Abuse Through Classification Algorithms, Faruk Bulut, İhsan Ömür Bucak
An Urgent Precaution System To Detect Students At Risk Of Substance Abuse Through Classification Algorithms, Faruk Bulut, İhsan Ömür Bucak
Turkish Journal of Electrical Engineering and Computer Sciences
In recent years, the use of addictive drugs and substances has turned out to be a challenging social problem worldwide. The illicit use of these types of drugs and substances appears to be increasing among elementary and high school students. After becoming addicted to drugs, life becomes unbearable and gets even worse for their users. Scientific studies show that it becomes extremely difficult for an individual to break this habit after being a user. Hence, preventing teenagers from addiction becomes an important issue. This study focuses on an urgent precaution system that helps families and educators prevent teenagers from developing …
Star-Crossed Cube: An Alternative To Star Graph, Nibedita Adhikari, Chitta Ranjan Tripathy
Star-Crossed Cube: An Alternative To Star Graph, Nibedita Adhikari, Chitta Ranjan Tripathy
Turkish Journal of Electrical Engineering and Computer Sciences
This paper introduces a new interconnection network topology called the star-crossed cube (SCQ). The SCQ is observed to be superior to other contemporary networks in terms of various topological parameters such as diameter, cost, average distance, and message traffic density. The various performance metrics of the proposed network, including cost effectiveness and time-cost effectiveness, are found to be better. The optimal routing and broadcasting algorithms for the new network are also presented. Embedding properties for the proposed network are also studied.
Retinal Image Analysis Using Multidirectional Functors Based On Geodesic Conversions, Saleh Shahbeig
Retinal Image Analysis Using Multidirectional Functors Based On Geodesic Conversions, Saleh Shahbeig
Turkish Journal of Electrical Engineering and Computer Sciences
A retinal image contains vital information. Extracting these features is the first and most important step in the analysis of retinal images for various applications of medical or human recognition. In this study, a morphological-based blood vessel extraction algorithm using adaptive-local analysis from colored retinal images is proposed. In this algorithm, by applying the appropriate morphology functors and local histogram stretching on the retinal images, the brightness of the images is considerably uniformed. Furthermore, curvelet transform (CT) is used to enhance the retinal images by highlighting the edges of the images in various scales and directions and by the adaptive …
Correlation Analysis Between Surface Electromyography And Continuous-Wave Near-Infrared Spectroscopy Parameters During Isometric Exercise To Volitional Fatigue, Ömer Şayli̇, Ata Akin, Hasan Bi̇rol Çotuk
Correlation Analysis Between Surface Electromyography And Continuous-Wave Near-Infrared Spectroscopy Parameters During Isometric Exercise To Volitional Fatigue, Ömer Şayli̇, Ata Akin, Hasan Bi̇rol Çotuk
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, the process of muscular fatigue was examined using surface electromyography (sEMG) and continuous-wave near-infrared spectroscopy (cw-NIRS) simultaneously during an isometric hand grip exercise at 50% and 75% of the maximal voluntary contraction (MVC), sustained until volitional fatigue. The mean frequency of the sEMG decreased during the whole exercise, whereas the root mean square had a tendency to increase. Oxyhemoglobin/deoxyhemoglobin concentration changes computed with cw-NIRS were found to exhibit a fast linear decrease/increase in the first 10--20 s of the exercise, the so-called fast phase, followed by a plateau-like slow phase. The change rates were higher at 75% …
Simultaneous Identification And Correction Of Measurement And Branch Parameter Errors, Mehdi Ahmadi Jirdehi, Mehrdad Tarafdar Hagh, Kazem Zare
Simultaneous Identification And Correction Of Measurement And Branch Parameter Errors, Mehdi Ahmadi Jirdehi, Mehrdad Tarafdar Hagh, Kazem Zare
Turkish Journal of Electrical Engineering and Computer Sciences
The performance of the state estimation (SE) depends on the accuracy of the received measured data, as well as the parameter data of the power system. In this paper, a new algorithm is proposed for the simultaneous identification and correction of measurement and branch parameter errors (series and shunt admittances) in the power system SE problem. The proposed method uses Lagrange multipliers for the identification and correction of branch parameter errors without the need for a-priori specification of suspect parameter vectors. Erroneous measurements and branch parameter values can be corrected using the proposed method to estimate the measurement and branch …
Multifunction Converter Based On Lyapunov Function Used In A Photovoltaic System, Trung Nhan Nguyen, An Luo
Multifunction Converter Based On Lyapunov Function Used In A Photovoltaic System, Trung Nhan Nguyen, An Luo
Turkish Journal of Electrical Engineering and Computer Sciences
The development of distributed generations (DGs) is essential to help solve energy crises and improve the reliability of electricity supplies. However, the involvement of a DG in a grid along with an increase of the nonlinear load will reduce the power quality. To solve this problem, we want the converter used in the DG to work flexibly, intelligently, and more accurately. To contribute to the improvement of quality of the DG, this paper proposes a multifunction converter (MFC) model. With the proposed model, the photovoltaic generator, which can be operated at harmonic suppression, and the power injection are more flexible …
Performance Evaluation Of The Wave Atom Algorithm To Classify Mammographic Images, Nebi̇ Gedi̇k, Ayten Atasoy
Performance Evaluation Of The Wave Atom Algorithm To Classify Mammographic Images, Nebi̇ Gedi̇k, Ayten Atasoy
Turkish Journal of Electrical Engineering and Computer Sciences
The most common type of cancer seen in women is breast cancer. To enable recovery from this severe disease, monitoring and early detection must be provided, and related precautions must be taken as a first step. During diagnosis, some cases may be overlooked due to fatigue and eyestrain, because the determination of abnormalities is a repetitive procedure. In this study, a computer-aided diagnosis (CAD) system, using the wave atom transform (WAT) algorithm and support vector machine (SVM), is proposed to evaluate mammography images. During the process, the region of interest (ROI) is defined before applying the method. The system includes …
Fuzzy Logic Approach To Henry Factor For Distributed Feedback Laser Case, Abdullah Çavuşoğlu
Fuzzy Logic Approach To Henry Factor For Distributed Feedback Laser Case, Abdullah Çavuşoğlu
Turkish Journal of Electrical Engineering and Computer Sciences
In this study, a simple approach for intelligent modeling of the Henry factor (\alpha-alpha parameter, antiguiding factor, phase-amplitude coupling factor) or the so-called linewidth enhancement factor, which is an actual analysis and design parameter for semiconductor laser diodes and optical communication systems, is proposed based on the fuzzy logic (FL) phenomenon. The proposed FL-based model easily computes the Henry factor in terms of different wavelengths and injection current levels (i.e. the inputs of the model). The experimental data belong to a distributed feedback laser, obtained from amplified spontaneous emission spectra, which is among the techniques required for the characterization of …
A Reduced Probabilistic Neural Network For The Classification Of Large Databases, Abdelhadi Lotfi, Abdelkader Benyettou
A Reduced Probabilistic Neural Network For The Classification Of Large Databases, Abdelhadi Lotfi, Abdelkader Benyettou
Turkish Journal of Electrical Engineering and Computer Sciences
The probabilistic neural network (PNN) is a special type of radial basis neural network used mainly for classification problems. Due to the size of the network after training, this type of network is usually used for problems with a small-sized training dataset. In this paper, a new training algorithm is presented for use with large training databases. Application to the handwritten digit database shows that the reduced PNN performs better than the standard PNN for all of the studied cases with a big gain in size and processing speed. This new type of neural network can be used easily for …
Statistical Approach For Determining Impulse Breakdown Voltage Distribution Under Dc Sweep Voltage, Mehmet Demi̇r, Celal Koraşli
Statistical Approach For Determining Impulse Breakdown Voltage Distribution Under Dc Sweep Voltage, Mehmet Demi̇r, Celal Koraşli
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a comprehensive approach to the statistical characterization of impulse breakdown voltage under the effect of a DC sweep voltage. Several goodness-of-fit tests are applied to up-and-down test results obtained in the air-insulated rod-plane gap. Three distributions, normal, logistic, and Gumbel, are compared by means of the Kolmogorov--Smirnov goodness-of-fit test, and logistic distribution is also compared to 3-parameter Weibull distributions using the likelihood ratio test. Logistic distribution is found to be a possible alternative to normal and 3-parameter Weibull distributions.
Motion Clustering On Video Sequences Using A Competitive Learning Network, Sali̇h Görgünoğlu, Şafak Altay
Motion Clustering On Video Sequences Using A Competitive Learning Network, Sali̇h Görgünoğlu, Şafak Altay
Turkish Journal of Electrical Engineering and Computer Sciences
It is necessary to track human movements in crowded places and environments such as stations, subways, metros, and schoolyards, where security is of great importance. As a result, undesired injuries, accidents, and unusual movements can be determined and various precautionary measures can be taken against them. In this study, real-time or existing video sequences are used within the system. These video sequences are obtained from objects such as humans or vehicles, moving actively in various environments. At first, some preprocesses are made respectively, such as converting gray scale, finding the edges of the objects existing in the images, and thresholding …
Btsql: Nested Bitemporal Relational Database Query Language, Canan Atay, Abdullah Uz Tansel
Btsql: Nested Bitemporal Relational Database Query Language, Canan Atay, Abdullah Uz Tansel
Turkish Journal of Electrical Engineering and Computer Sciences
A nested bitemporal relational data model and its query language are implemented. The bitemporal atom (BTA) is the fundamental construct to represent temporal data and it contains 5 components: a value, the lower and upper bounds of valid time, and the lower and upper bounds of the recoding time. We consider 2 types of data structures for storing BTAs: 1) string representation and 2) abstract data-type representation. We also develop a preprocessor for translating a bitemporal structured query language (BtSQL) statement into standard SQL statements. The BtSQL includes the select, insert, delete, and update statements of the SQL, extended for …
Bi Input-Extended Kalman Filter-Based Speed-Sensorless Control Of An Induction Machine Capable Of Working In The Field-Weakening Region, Remzi̇ İnan, Murat Barut
Bi Input-Extended Kalman Filter-Based Speed-Sensorless Control Of An Induction Machine Capable Of Working In The Field-Weakening Region, Remzi̇ İnan, Murat Barut
Turkish Journal of Electrical Engineering and Computer Sciences
This study introduces a novel bi input-extended Kalman filter (BI-EKF)-based speed-sensorless direct vector control (DVC) of an induction motor (IM). The proposed BI-EKF-based estimator includes online estimations of the stator stationary axis components of the stator currents, i_{s\alpha} and i_{s\beta}; stator stationary axis components of the rotor flux, \varphi_{r\alpha} and \varphi_{r\beta}; rotor angular velocity, \omega_m; stator resistance, R_s; rotor resistance, R_r; and load torque t_L, as well as the magnetizing inductance, L_m, by only supposing that the stator phase currents and voltages are measured. Thus, the speed-sensorless DVC of the IM with the inclusion of the proposed estimator is able …
Control Of Svc Based On The Sliding Mode Control Method, Ercan Köse, Hakan Kizmaz, Kadi̇r Abaci, Saadetti̇n Aksoy
Control Of Svc Based On The Sliding Mode Control Method, Ercan Köse, Hakan Kizmaz, Kadi̇r Abaci, Saadetti̇n Aksoy
Turkish Journal of Electrical Engineering and Computer Sciences
A genetic algorithm (GA)-based sliding mode controller is proposed to improve the voltage stability of a power system with a static var compensator. The proposed controller is examined for improving the load bus voltage, which changes under different demanding powers, and its performance for transient analysis is compared with the Ziegler--Nichols proportional-integral (ZNPI), Lyapunov-based sliding mode control (LASMC), and GA-based proportional-integral-derivative (GAPID) controllers. The dynamic equations, consisting of a 2-bus nonlinear system, are converted to a mathematical description of sliding mode techniques. The optimum values of the sliding mode controller and proportional-integral-derivative (PID) coefficients that are required are calculated using …
Discovery Of Hydrometeorological Patterns, Mete Çeli̇k, Fi̇li̇z Dadaşer Çeli̇k, Ahmet Şaki̇r Dokuz
Discovery Of Hydrometeorological Patterns, Mete Çeli̇k, Fi̇li̇z Dadaşer Çeli̇k, Ahmet Şaki̇r Dokuz
Turkish Journal of Electrical Engineering and Computer Sciences
Hydrometeorological patterns can be defined as meaningful and nontrivial associations between hydrological and meteorological parameters over a region. Discovering hydrometeorological patterns is important for many applications, including forecasting hydrometeorological hazards (floods and droughts), predicting the hydrological responses of ungauged basins, and filling in missing hydrological or meteorological records. However, discovering these patterns is challenging due to the special characteristics of hydrological and meteorological data, and is computationally complex due to the archival history of the datasets. Moreover, defining monotonic interest measures to quantify these patterns is difficult. In this study, we propose a new monotonic interest measure, called the hydrometeorological …
Application Of Hilbert--Huang Transform And Support Vector Machine For Detection And Classification Of Voltage Sag Sources, Alireza Foroughi, Ebrahim Mohammadi, Saeid Esmaeili
Application Of Hilbert--Huang Transform And Support Vector Machine For Detection And Classification Of Voltage Sag Sources, Alireza Foroughi, Ebrahim Mohammadi, Saeid Esmaeili
Turkish Journal of Electrical Engineering and Computer Sciences
Power quality disturbances, including voltage sag, swell, harmonics, flicker, and notch, are one of the main concerns for industries and electrical equipment. Among these disturbances, voltage sag, due to its irrecoverable economic effects on industries, is particularly important. In this paper, the detection and classification of voltage sag sources containing motor starting, short circuit, transformer energizing, and the reacceleration of motors after fault clearance using the Hilbert--Huang transform (HHT) and support vector machine (SVM) are studied. A voltage sag waveform includes several oscillating modes; for separating these oscillating modes, which are called intrinsic mode functions (IMFs), empirical mode decomposition is …
New Approach Using Structure-Based Modeling For The Simulation Of Real Power/Frequency Dynamics In Deregulated Power Systems, Mostafa Eidiani, Hossein Zeynal
New Approach Using Structure-Based Modeling For The Simulation Of Real Power/Frequency Dynamics In Deregulated Power Systems, Mostafa Eidiani, Hossein Zeynal
Turkish Journal of Electrical Engineering and Computer Sciences
Load frequency control (LFC) is one of the significant ancillary services in the electricity markets. The major concerns with LFC models have long been their dynamic response and complexity, as well as market price sensitivity. To cater to the complexity of the dynamic model that is introduced by the LFC and algebraic constraints by the transmission network, the differential-algebraic equation is transformed into a set of ordinary differential equations. This is done by differentiating the network constraints under a certain assumption that can be held throughout the system. To make the model suitable in a market environment, the real power …
Design And Realization Of A Welding Oscillator, Muci̇z Özcan
Design And Realization Of A Welding Oscillator, Muci̇z Özcan
Turkish Journal of Electrical Engineering and Computer Sciences
Welding is one of the most popular methods to combine metal pieces in manufacturing processes. Arc welding, among all welding techniques, is the most commonly used in manufacturing due to its cost and flexibility. During the manufacturing process, arc welding is either performed by an operator or by automatic tools such as welding oscillators. Using automatic tools has advantages over manual use, as the process will be faster, cheaper, and have less welding flaws. In this paper, a homemade welding oscillator and the method to manufacture it are presented. The presented welding oscillator can be manufactured for a very low …
Predics: A New Go-Po-Based Ray Launching Simulator For The Calculation Of Electromagnetic Scattering And Rcs From Electrically Large And Complex Structures, Caner Özdemi̇r, Betül Yilmaz, Özkan Kirik
Predics: A New Go-Po-Based Ray Launching Simulator For The Calculation Of Electromagnetic Scattering And Rcs From Electrically Large And Complex Structures, Caner Özdemi̇r, Betül Yilmaz, Özkan Kirik
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we present a new simulator called pRediCS for the calculation of electromagnetic scattering and radar cross-section (RCS) from electrically large and complex targets. The simulator utilizes the geometric optics (GO) theory and launching of electromagnetic rays for tracing and calculating the electric field values as the electromagnetic waves bounce around the target. The physical optics (PO) theory is also exploited to calculate the final scattered electric field by calculating the far-field PO integration along the observation direction. The simulator is first tested with known objects of canonical shapes, whose analytical solutions are available in the literature. Next, …
A New Approach Of Nonblind Watermarking Methods Based On Dwt And Svd Via Lu Decomposition, Onur Jane, Ersi̇n Elbaşi
A New Approach Of Nonblind Watermarking Methods Based On Dwt And Svd Via Lu Decomposition, Onur Jane, Ersi̇n Elbaşi
Turkish Journal of Electrical Engineering and Computer Sciences
Multimedia security has been the focal point of considerable research activity in the last decade, mainly because of its wide application area. Watermarking, in particular, is identified as a major technology to achieve copyright protection and multimedia security. Therefore, recent studies in the literature include some evident approaches for embedding data into a multimedia element. Because of its useful frequency component separation, the discrete wavelet transform (DWT) is commonly used in watermarking schemes. Moreover, singular value decomposition (SVD) and lower-and-upper (LU) decomposition have little effect on the perception of the watermark. Therefore, in this study, a combination of DWT and …
Dynamics, Stability, And Actuation Methods For Powered Compass Gait Walkers, Koray Kadi̇r Şafak
Dynamics, Stability, And Actuation Methods For Powered Compass Gait Walkers, Koray Kadi̇r Şafak
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, methods to achieve actively powered walking on level ground using a simple 2-dimensional walking model (compass-gait walker) are explored. The walker consists of 2 massless legs connected at the hip joint, a point mass at the hip, and an infinitesimal point mass at the feet. The walker is actuated either by applying equal joint torques at the hip and ankle, by an impulse applied at the toe off, immediately before the heel strike, or by the combination of both. It is shown that actuating the walker by equal joint torques at the hip and ankle on level …
Frequency-Emulated Uniform Cellular Automata, Hürevren Kiliç
Frequency-Emulated Uniform Cellular Automata, Hürevren Kiliç
Turkish Journal of Electrical Engineering and Computer Sciences
The notion of a frequency-emulated (f-emulated) uniform cellular automata (CA) that enables the behavior emulation of some elementary CA via memory usage is introduced. An algorithm that generates f-emulated uniform CA sets is developed and an upper bound for its output size is given. It is observed that traffic rule 184 together with its 2-emulator version, which generates the behavior of the known majority rule 232, performs the density classification task perfectly. Moreover, it is possible to use a 2-emulated uniform CA for the solution of the parity problem.
Spectrophotometric Determination Of Molybdenum Using Surfactant-Mediated Liquid--Liquid Extraction, Rameshwar Dass, Jitander Kumar Kapoor, Sunita Gambhir
Spectrophotometric Determination Of Molybdenum Using Surfactant-Mediated Liquid--Liquid Extraction, Rameshwar Dass, Jitander Kumar Kapoor, Sunita Gambhir
Turkish Journal of Chemistry
A new spectrophotometric method has been developed for determination of molybdenum using surfactant-mediated liquid--liquid extraction. Molybdenum(V) obtained by ascorbic acid reduction in 2.5 M H_2SO_4 reacted spontaneously with thiocyanate and cetyl trimethyl ammonium bromide (CTAB), forming an intense orange yellow complex that was extracted quantitatively into 1,2-dichloroethane and absorbed at 460 nm. The absorbance of the extract was found to be stable for more than 24 h. Beer's law was obeyed over the concentration range 0.1--4.2 \mu g Mo mL^{-1} of the extract. The linear range for an accurate determination was found to be 1.2--2.6 \mu g Mo mL^{-1}. The …
Application Of Guanidine And Its Salts In Multicomponent Reactions, Mahshid Rahimifard, Ghodsi Mohammadi Ziarani, Boshra Malekzadeh Lashkariani
Application Of Guanidine And Its Salts In Multicomponent Reactions, Mahshid Rahimifard, Ghodsi Mohammadi Ziarani, Boshra Malekzadeh Lashkariani
Turkish Journal of Chemistry
This review gives an overview of the application of guanidine and its salts in multicomponent reactions. It can act as a catalyst or solvent for multicomponent reactions or as a reagent for synthesis of substituted diazines, triazines, and macroheterocycles by multicomponent reactions.
Preparation And Characterization Of Nonmetal Promoter Modified Cuznal Catalysts For Higher Alcohol From Synthesis Gas Through Complete Liquid Phase Method, Shirui Yu, Xiaodong Wang, Wei Huang
Preparation And Characterization Of Nonmetal Promoter Modified Cuznal Catalysts For Higher Alcohol From Synthesis Gas Through Complete Liquid Phase Method, Shirui Yu, Xiaodong Wang, Wei Huang
Turkish Journal of Chemistry
A complete liquid phase technology and a function regulator were applied to prepare CuZnAl catalysts for higher alcohol synthesis. Characterizations showed that the introduction of the function regulator can change the reduction ability of copper oxides and the surface basicity of catalysts. Activity tests indicated that the selectivity of higher alcohol is high when considerable medium-strong basicity and the synergistic effects of copper ion and metal copper exist on the catalytic surface. The optimized modified CuZnAl catalyst without any metal additives provides a CO conversion of 28.9%, C_{2+}OH selectivity of up to 42.8%, and hydrocarbon selectivity of 2.5%, with a …