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Effect of the cation Size Disorder at the A-Site on the Structural Properties of SrAFeTiO6Double Perovskites (A = La, Pr or Nd)

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Journal of Materials Science and Chemical Engineering 2015年第5期3卷 21-29页

作者： Abdelrahman A. Elbadawi O. A. Yassin Mohamed A. Siddig Department of Physics Faculty of Science and Technology Alneelain University Khartoum Sudan Department of Physics Faculty of Science Tiabah University Medina Saudi Arabia

In this paper, the cation size disorder effect of the A-site on the structural properties of the SrAFe- TiO6 (A = La, Pr or Nd) was investigated. The compounds were synthesized—as the best of our knowledge—for the first time by conventional and precursor method to get crystalline materials. The results obtained from the experimental measurements carried out on new double perovskite materials were presented. The data of X-ray diffraction (XRD), Fourier Transform Infra Red FTIR were measured at room temperature. From the X-ray diffraction, and by means of standard Rietiveld method, all the samples have the same structure (orthorhombic) with Pnma space group. The difference in the tolerance factor is clearly noticed and refers to the cation size disorder at the A-sites. The Fourier Transform Infra Red FTIR measurement has been done;the results of it confirm the double perovskite structure and the difference between the samples were noticed. The tolerance factors for the samples altered from SrLaFeTiO6 up to SrNdFeTiO6 and this difference return to ionic radius and cation size effect.

关键词： cation Disorder Double Perovskite Tolerance Factor

Synthesis of Bifunctional Poly(Vinyl Phosphonic Acid-co-glycidyl Metacrylate-co-divinyl Benzene) cation-Exchange Resin and Its Indium Adsorption

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Open Journal of Polymer Chemistry 2013年第4期3卷 104-112页

作者： Chi Won Hwang Chang Soo Lee Taek Sung Hwang Department of Applied Chemistry and Biological Engineering Chungnam National University Daejeon Korea

Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodi-acetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization, and their indium adsorption properties were investigated. The synthesized PVGD and IPVGD resins were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury porosimetry. The cation-exchange capacity, the water uptake and the indium adsorption properties were investigated. The cation-exchange capacities of PVGD and IPVGD were 1.2 - 4.5 meq/g and 2.5 - 6.4 meq/g, respectively. The water uptakes were decreased with increasing contents of divinyl benzene (DVB). The water uptake values were 25% - 40% and 20% - 35%, respectively. The optimum adsorption of indium from a pure indium solution and an artificial indium tin oxide (ITO) solution by the PVGD and IPVGD ion-exchange resins were 2.3 and 3.5 meq/g, respectively. The indium adsorption capacities of IPVGD were higher than those of PVGD. The indium ion adsorption selectivity in the artificial ITO solution by PVGD and IPVGD was excellent, and other ions were adsorbed only slightly.

关键词： Poly(Vinyl Phosphonic Acid-co-glycidyl Methacrylate-co-divinyl Benzene) PVGD Containing an Iminodiacetic Acid Group Bifunctional cation Exchanger Indium Tin Oxide Indium Adsorption

Comparison and Evaluation of Two Analytical Methods for cation Exchange Capacity and Exchangeable Sodium Percentage of Five Soil Types in Central Sudan

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Open Journal of Soil Science 2015年第12期5卷 311-318页

作者： Jamal Elfaki Mohamed Gafer Magboul Sulieman Mushtaha Ali Department of Seeds Technology Nile Valley University Atbara Sudan Soil and Water Science Department College of Agricultural Studies Sudan University of Science and Technology Shambat Sudan Department of Soil and Environment Sciences University of Khartoum Shambat Sudan General Administration of Natural Resource and Sustainable Development Khartoum Sudan

Twenty-six soil samples were collected from five soil profiles at different climatological and ecological regions in central Sudan. Soil profile was dug in each studied area and morphological profile description was carried out for different horizons. All samples were analyzed using two different methods to determine cation Exchange Capacity (CEC) and exchangeable sodium percentage (ESP). Statistical analysis (T-test) was used in order to investigate the differences between soil samples for the studied locations. Significant differences appeared when compared the two methods for CEC determination at Gedaref area, Wad Medani and Nile flood plain and that appeared in evaluation of ESP at Nile flood plain and Shambat area. The results also revealed that, the developed method used in this study was more practical, simple and reliable for determination of CEC and ESP as the currently used in most soil laboratories. In addition, it will be safer than the other methods in some problematic soils. The adoption of this developed method is advisable because it is less time consuming as it omits the washing step. In contrast, the old method cannot be a good substitute in laboratories which have no possibility to determine sodium by using flame photometer. We conclude that when the developed method is used to determine CEC and ESP time will be saved, that fewer amounts of chemicals will be used and that accurate results will be achieved.

关键词： Ecological Regions Central Sudan cation Exchange Capacity Exchangeable Sodium Percentage

Study on the Phosphenium cation (Ⅰ)——Synthesis and Characterization of 5-Methylthio-3-N-Phenyl-2,3-2(H)-1,3,4,2-Thiadiazaphosphenium cation and the Others

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Science China Chemistry 1993年第6期36卷 641-648页

作者：黄天宝张景龄湛昌国张友杰 Institute of Organic Synthesis Huazhong Normal University Wuhan 430070 PRC A Ph.D.studcnt Institute of Organic Synthesis Huazhong Normal University Wuhan 430070 PRC Director of Ph.D.dissertation Department of Chemistry Huazhong Normal University Wuhan 430070 PRC The Centre for Analysis and Testing Huazhong Normal University Wuhan 430070 PRC

Ten years after the first synthesis of neutral two-coordinated phosphorus in 1962, the first phosphenium cations were synthesized by Fleming, Lupton and Jekot in 1972. Up to now, though 30 years have passed, the members of these phosphenium cations are still very few. the research of phosphenium cations is only limited in France, America and other countries. In our laboratory work was done on a new unique cation: the 5-methylthio-3-N-phenyl-2,3-2（H）-1,3,4,2-thiadiazaphosphenium cation which was found and characterized by 261.9 ppm conclusively of 31p NMR. It also has an electric conductivity in nucleophilic and electrophilic reactions. We are interested in noticing that these phospbenium cations are stabilized by one sulfur atom besides nitrogen atoms.

关键词： phosphenium cation molar conductivity extended Hückel molecule orbital method Staudinger reaction aromatic electrophilic substitution.

Decrease in cation Exchange Capacity of Zeolites at Neutral pH: Examples and Proposals of a Determination Method

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Journal of Materials Science and Chemical Engineering 2014年第8期2卷 1-5页

作者： Moses Wazingwa Munthali Ponyadira Kabwadza-Corner Erni Johan Naoto Matsue Laboratory of Applied Chemistry for Environmental Industry Faculty of Agriculture Ehime University Matsuyama Japan

cation exchange capacity (CEC) is an important characteristic of zeolites, especially when they are used as adsorbents in the aqueous system. However, no international standard method exists for the determination of CEC of zeolites. We determined CEC of Linde-type A and Na-P1 type zeolites at various pH (4 to 10) with a simple method, where Na+-saturated zeolites were prepared, and then various amounts of HCl were added. CEC was simply calculated by subtracting the amount of Na+ in the final supernatant from the content of Na+ of the Na+-saturated zeolites. CEC of the zeolites decreased with decreasing pH and with decreasing Na+ concentration of the final supernatant. The concentration of Na+ of the supernatant, CEC of the zeolites began to decrease at weakly alkaline or neutral pH, and that of the Linde-type A zeolite became about half at pH around 6. When CEC was plotted against pH-pNa;where pNa is negative logarithm of the activity of Na+;CEC of each zeolite was expressed by a curve. It indicates that the CEC or the amount of Na+ retention is univocally determined by the ratio of activities of Na+ and proton.

关键词： cation Exchange Capacity Na+ Retention pH Dependence Linde-Type A Zeolite Na-P1 Type Zeolite

INFRARED AND.RAMAN SPECTRA AND NORMAL COORDINATE ANALYSIS OF THE [CH3NHC（SCH3）2]+ cation

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结构化学 1988年第1期 13-16页

作者： Lin ZhengyanFujian Institute of Research on the Structure of Matter, Academia SinicaR.Matters, CH. MendelInstitute of Inorganic Chemistry, University of Muenater(F. R. G)

INTRODUCTION. Considering the interesting bonding nature and the importance in some biochemical processes chemists and biochemists recently have made quite extensive investigations on the synthesis, structure and spectra of the sulfur-donor ligand compounds. We have performed determination of the molecular structures and the assignments of the vibrational spectra of three compounds, namely H2NCSSCH3, H2NCOSCH3 and H2NCSOCH3[1,2], and obtained the

关键词： SCH3 CS cation CH3NHC INFRARED AND.RAMAN SPECTRA AND NORMAL COORDINATE ANALYSIS OF THE

A new boundary element solution to evaluate the geometric effects of the canyon site on the displacement response spectrum

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Earthquake Engineering and Engineering Vibration 2019年第2期18卷 267-284页

作者： Reza Tarinejad Mohsen Isari Abbasali Taghavi Ghalesari Department of Civil Engineering University of Tabriz Department of Civil Engineering The University of Texas at El Paso 500 W University Ave.

This paper presents a step-by-step procedure using the three-dimensional boundary element approach to study the behavior of semi-circular canyons under seismic shear waves. The boundary element code TDASC allows utilization for various canyon geometries, evaluation of concurrent seismic waves and calculation of the ground motions on canyons due to an excitation at any arbitrary point of the incident field. Considering the widening ratio of the canyon(including prismatic, semi-prismatic and non-prismatic canyons), wave characteristics(wavelength, dimensionless period, direction) and maximum amplification pattern, the solution was applied to carry out a series of parametric studies. It was shown that canyon form can significantly affect the displacement amplification, especially at the points located on its edges. By increasing the wave dimensionless frequency(η > 1), the amplification pattern becomes more complex. On the basis of the results from a variety of considered cases, a new expression has been presented for the limiting wavelength beyond which the widening of the canyon will not have a major effect on the displacement amplification. To verify the reliability of the proposed approach, the obtained results, expressed in terms of displacement amplitude, were compared with those from the available published literature and a reasonably good agreement was observed.

关键词： canyon boundary element method widening ratio site effect wave scattering amplifi cation

Influence of monovalent cations and CuO nanoparticles on X-nanozeolite in uranium anionic species separation from contaminated drinking water

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Chinese Journal of Chemical Engineering 2017年第6期25卷 782-792页

作者： H.R. Shakur Kh. Rezaee Ebrahim Saraee M.R. Abdi G. Azimi Department of Nuclear Engineering Faculty of Advance Sciences and Technologies University of lsfahan Isfahan 81746-73441 lran Department of Physics Faculty of science University of lsfahan lsfahan 81747-73441 Iran Department of Chemistry University of lsfahan lsfahan 81747-73441 Iran

The main purpose of this work was the modification of NaX nanozeolite using copper oxide nanoparticles and various monovalent cations such as K^+, Cs^+, and Ag^+in order to make the negatively charged zeolite surface accessible for anionic forms of uranium which are the most dominant species of uranium in the contaminated radioactive waters at natural p H. Various methods such as the X-ray fluorescence(XRF), X-ray powder diffraction(XRD), field emission scanning electron microscopy(FE-SEM), transmission electron microscopy(TEM), Fourier transform infrared spectroscopy(FT-IR), and atomic absorption spectroscopy(AAS) were used to characterize the final synthesized absorbents. Batch technique was used to study the adsorption behavior of uranium ions from polluted drinking water by Na X nanozeolite and its modified forms. In order to better understand the performance of them, the results were compared with those that were obtained for synthesizing bulk NaX zeolite and Na-form of clinoptilolite natural zeolite. Preliminary results indicated that uranium sorption increased as the loading level of CuO nanoparticles on NaX nanozeolite increased from 2.1 wt% to 11.2 wt%. In addition,from the obtained data, an increase in uranium removal efficiency resulted as charge/ionic radius ratio of exchanged cation decreased. Also, the effect of contact time, solid–liquid ratio, initial concentration and temperature on the adsorption process was studied. It is worth mentioning that, in this study, the sorption of uranium was performed under natural conditions of pH and the presence of competing cations and anions which are available in drinking waters.

关键词： Zeolite Monovalent cation NaX/CuO nanocomposite Uranium anions Separation Waste water

Smart Semi-active PID-ACO control strategy for tower vibration reduction in Wind Turbines with MR damper

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Earthquake Engineering and Engineering Vibration 2019年第4期18卷 887-902页

作者： Mahmudur Rahman Zhi Chao Ong Wen Tong Chong Sabariah Julai Department of Mechanical Engineering Faculty of Engineering University of Malaya

Wind turbine technology is well known around the globe as an eco-friendly and eff ective renewable power source. However, this technology often faces reliability problems due to structural vibration. This study proposes a smart semi-active vibration control system using Magnetorheological (MR) dampers where feedback controllers are optimized with nature-inspired algorithms. Proportional integral derivative (PID) and Proportional integral (PI) controllers are designed to achieve the optimal desired force and current input for MR the damper. PID control parameters are optimized using an Ant colony optimization (ACO) algorithm. The eff ectiveness of the ACO algorithm is validated by comparing its performance with Ziegler-Nichols (Z-N) and particle swarm optimization (PSO). The placement of the MR damper on the tower is also investigated to ensure structural balance and optimal desired force from the MR damper. The simulation results show that the proposed semi-active PID-ACO control strategy can signifi cantly reduce vibration on the wind turbine tower under diff erent frequencies (i.e., 67%, 73%, 79% and 34.4% at 2 Hz, 3 Hz, 4.6 Hz and 6 Hz, respectively) and amplitudes (i.e. 50%, 58% and 67% for 50 N, 80 N, and 100 N, respectively). In this study, the simulation model is validated with an experimental study in terms of natural frequency, mode shape and uncontrolled response at the 1st mode. The proposed PID-ACO control strategy and optimal MR damper position is also implemented on a lab-scaled wind turbine tower model. The results show that the vibration reduction rate is 66% and 73% in the experimental and simulation study, respectively, at the 1st mode.

关键词： ant colony optimization fi nite diff erence method magnetorheological damper PID-ACO controller semiactive control system identifi cation wind turbine tower