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181.
In this study, a coupled-channel (CC) analysis of the elastic and the inelastic scattering of 20.4 MeV polarized protons from
a 64Zn target leading to the deformed 2 + , 3 −, 22+2_2^+ states was performed. The CC potential parameters and the deformation parameters of the excited states corresponding to the
best fit to the experimental differential cross-sections and the analysing powers data were determined. For 22+2_2^+ excited state, a mixed type was used and a good fit to the data was provided. The CC calculation results were compared to
the pure distorted wave Born approximation (DWBA) calculation results which were calculated using the new parameters. All
calculations were conducted using the computer code ECIS06. 相似文献
182.
In this work, we aim a detailed investigation of the electronic properties of a spherical multi-layer quantum dot with and without a hydrogenic impurity. The structure is introduced in the form of core/shell/well/shell layers. The core and well layers are defined by the parabolic electronic potentials. We carry out the effect of the core radius and layer thickness on the energy levels, their wave functions, binding energies of the impurity and the probability distributions. In order to determine the sublevel eigenvalues and eigenfunctions, the Schrödinger equation is solved full numerically by shooting method in the frame of the effective mass approximation. The results are analyzed in detail as a function of the layer thicknesses and their probable physical reasons are tried to be explained. It is found that the electronic properties and impurity binding energies are strongly depending on the layer thicknesses. 相似文献
183.
Osman B Özer ET Kara A Güçer Ş Beşirli N 《Journal of colloid and interface science》2012,378(1):167-174
The barium hexaferrite (BaFe(12)O(19)) containing magnetic poly (ethylene glycol dimethacrylate-vinyl pyridine; mag-poly [EGDMA-VP]) beads (average diameter=53-212 μm) were synthesized and characterized. Their use as an adsorbent in the removal of dimethyl phthalate (DMP) from an aqueous solution was investigated. The mag-poly (EGDMA-VP) beads were prepared by copolymerizing of 4-vinyl pyridine (VP) with ethylene glycol dimethacrylate (EGDMA). The mag-poly (EGDMA-VP) beads were characterized by N(2) adsorption/desorption isotherms (BET), vibrating sample magnetometer (VSM), X-ray powder diffraction (XRD), elemental analysis, scanning electron microscope (SEM), and swelling studies. At a fixed solid/solution ratio, the various factors affecting the adsorption of DMP from aqueous solutions such as pH, initial concentration, contact time, and temperature were analyzed. The maximum DMP adsorption capacity of the mag-poly (EGDMA-VP) beads was determined as 96.2 mg/g at pH 3.0, 25 °C. All the isotherm data can be fitted with both the Langmuir and the Dubinin-Radushkevich isotherm models. The pseudo-first-order, pseudo-second-order, Ritch-second-order, and intraparticle diffusion models were used to describe the adsorption kinetics. The thermodynamic parameters obtained indicated the exothermic nature of the adsorption. The DMP adsorption capacity did not change after 10 batch successive reactions, demonstrating the usefulness of the magnetic beads in applications. 相似文献
184.
A simple and efficient synthesis for the preparation of unusual charge‐separated pyridinium (thio)barbiturate zwitterion derivatives was achieved via a one‐pot reaction of (thio)barbituric acid derivatives and 2‐pyridinecarbaldehyde under solvent‐free condition and also in methanol under refluxing. The structure of the compounds was confirmed by 1H NMR, 13C NMR, FT‐IR, mass and X‐ray analysis. The mechanism of the formation is discussed. Instead, no related pyridinium zwitterion was afforded from the reaction between dimedone and 2‐pyridinecarbaldehyde under the same conditions and its xanthene derivative was obtained. 相似文献
185.
Şahin Yıldırım 《Nonlinear dynamics》2008,52(3):207-215
The use of a proposed recurrent neural network control system to control a four-legged walking robot is presented in this
paper. The control system consists of a neural controller, a standard PD controller, and the walking robot. The robot is a
planar four-legged walking robot. The proposed Neural Network (NN) is employed as an inverse controller of the robot. The
NN has three layers, which are input, hybrid hidden and output layers. In addition to feedforward connections from the input
layer to the hidden layer and from the hidden layer to the output layer, there is also a feedback connection from the output
layer to the hidden layer and from the hidden layer to itself. The reason to use a hybrid layer is that the robot’s dynamics
consists of linear and nonlinear parts. The results show that the neural-network controller can efficiently control the prescribed
positions of the stance and swing legs during the double stance phase of the gait cycle after sufficient training periods.
The goal of the use of this proposed neural network is to increase the robustness of the control of the dynamic walking gait
of this robot in the case of external disturbances. Also, the PD controller alone and Computed Torque Method (CTM) control
system are used to control the walking robot’s position for comparison. 相似文献
186.
Accuracy and precision of position control of hydraulic systems are key parameters for engineering applications in order to
set more economical and quality systems. In this context, this paper presents modeling and position control of a hydraulic
actuation system consisting of an asymmetric hydraulic cylinder driven by a four way, three position proportional valve. In
this system model, the bulk modulus is considered as a variable. In addition, the Hybrid Fuzzy-PID Controller with Coupled
Rules (HFPIDCR) is proposed for position control of the hydraulic system and its performance is tested by simulation studies.
The novel aspect of this controller is to combine fuzzy logic and PID controllers in terms of a switching condition. Simulation
results of the HFPIDCR based controller are compared with the results of classical PID, Fuzzy Logic Controller (FLC), and
Hybrid Fuzzy-PID controller (HFPID). As a result, it is demonstrated that Hybrid Fuzzy PID Controller with Coupled Rules is
more effective than other controllers. 相似文献
187.
Şenay Yurdakul M. Tahir Güliüoğlu 《Journal of inclusion phenomena and macrocyclic chemistry》2001,40(3):231-237
Infrared spectra of M(piperidine)2Ni(CN)4.0.5G (M=Co, Ni or Cu;G= chlorobenzene, 1,2-dichlorobenzene or 1,3-dichlorobenzene; M=Co or Ni;G=1,4-dichlorobenzene) compounds are reported. The piperidine molecules inthe host permit the inclusion of bulky guest molecules. The spectral featuressuggest that the compounds are similar in structure to the Hofmann-type clathrates. 相似文献
188.
Summary A new method has been developed for the quantitative determination of gas mixture composition where air penetration during
gas sample collection would lead to erroneous results. It requires the use of a stationary phase that separates gas sample
components and the air and involves 4–5 analyses of samples of equal volumes containing different amounts of air. By graphical
extrapolation of the air peak area (S
air
) as a function of the peak areas of the individual components (S
comp
) the areas for these components in the absence of air can be obtained forS
air
=0.
Using calibration curves for the pure gas components the true quantitative composition of the gas mixture is estimated. 相似文献
189.
For a class of risk-sensitive nonlinear stochastic control problems with dynamics in strict-feedback form, we obtain through a constructive derivation state-feedback controllers which (i) are locally optimal, (ii) are globally inverse optimal, and (iii) lead to closed-loop system trajectories that are bounded in probability. The first feature implies that a linearized version of these controllers solve a linear exponential-quadratic Gaussian (LEQG) problem, and the second feature says that there exists an appropriate cost function according to which these controllers are optimal. 相似文献
190.
Ojaghi Aghbash Khadijeh Noroozi Pesyan Nader Marandi Ghasem Dege Necmi Şahin Ertan 《Research on Chemical Intermediates》2019,45(9):4543-4554
Research on Chemical Intermediates - A safe, green and convenient process was developed for the synthesis of a novel group of 4,8-dihydropyrano[3,2-b]-pyrans by dialkyl acetylenedicarboxylates and... 相似文献