Ion pairing, H-bonding, and π–π interactions in copper(II) complex-organo-networks derived from a proton-transfer compound of the 1,10-phenanthroline-2,9-dicarboxylic acid

The one-pot reaction between the novel proton transfer compound (pydaH₂)²⁺(phendc)²⁻, LH₂, and Cu(II) afforded the compounds (pydaH)₂[Cu(phendc)₂]·10H₂O, 1, and (pydaH)₂[Cu(phendc)(phendcH)]₂·5H₂O, 2, where pyda=2,6-diaminopyridine, and phendcH₂=1,10-phenanthroline-2,9-dicarboxylic acid. The single crystal X-ray diffraction analysis of 1 and 2 revealed that these are two novel self-assembled 3D Cu(II) complex-organo-networks, in which (pydaH)⁺ ions and [Cu(phendc)₂]²⁻ or complex units are held together by ion pairing, H-bonding, and π–π interactions. Magnetic measurements over the temperature range 1.8–310 K revealed no significant magnetic coupling between Cu(II) centers in 1 or 2.     

Specific Uphill Transport of Zinc as Zn(SCN)42− Ion using Na+-Dicyclohexyl-18-Crown-6 as Carrier

Sodium-dicyclohexyl- 18-crown-6 complex cation was used as carrier for the uphill transport of zinc as Zn(SCN)₄^2? complex anion. By using L-cysteine as a metal ion acceptor in the receiving phase at the optimized pH of 7.6, the amount of zinc transport through the liquid membrane after 90 min was 97.2 ± 1.0%. The selectivity and efficiency of zinc transport from aqueous solutions containing equimolar mixtures of Ag⁺, Cd²⁺ Co²⁺, Cu²⁺, Fe²⁺, Ni²⁺, Pb²⁺, Pd²⁺, Sr²⁺, Bi³⁺, Cr³⁺ and Fe³⁺ ions was investigated. In the presence of NH₂OH.HCl as a suitable masking agent in the source phase, the interfering effect of Cu²⁺ and Pb²⁺ ions was diminished drastically.     

Sono-chemical synthesis and characterization of Fe3O4@mTiO2-GO nanocarriers for dual-targeted colon drug delivery

Research on Chemical Intermediates - In this study, a kind of magnetic Fe3O4@mTiO2-GO (where m was shorted mesoporous) hybrids with core–shell nano-structure for controlled dual targeted drug...     

Preconcentration and Separation of Trace Amounts of Strontium Ions from Alkali and Alkaline Earth Metal Ions Using Octadecyl Silica Membrane Disks Modified with Decyl-18-Crown-6 and Its Determination by Flame Atomic Absorption Spectrometry

 A simple and reliable method for rapid and selective separation of trace amounts of Sr²⁺ ions from alkali and alkaline earth metal ions by using octadecyl silica membrane disks modified with decyl- 18-crown-6 in the presence of 1.0 × 10⁻³ M picric acid is presented. The influence of picric acid concentration, flow rates and nature and amount of the stripping acid have been investigated. Maximum capacity of the membrane disks modified with 10 mg of the macrocycle was found to be 484 μg of Sr²⁺ ions. The proposed method permitted enrichment factors of about 80 and higher. The limit of detection of the proposed method is 1.5 μg per 1000 ml. The method was successfully applied to the recovery of Sr²⁺ ions from different synthetic and water samples. Received August 10, 2000. Revision April 17, 2001.     

Experimental determination of acetamiprid pesticide residue in three different types of pistachio by ion mobility spectrometry and using QuEChERS method in the different temperatures and in the presence of ammonia as dopant gas

In this project, Ion Mobility Spectrometer (IMS) instrument in the positive mode and with corona ionization source was utilized to determine the residue of acetamiprid pesticide in three different types of pistachio (Akbari, Fandoghi and Kalachuchi). The QuEChERS method, notable because of easy and quick preparation of sample and using lower amounts of organic solvents with harmful environmental effects and high costs, was used in this study. Many experiments were performed in the different temperatures in order to obtain optimum temperature for cell and injection. Ammonia and acetone were considered as dopant substances and it turned out that the ammonia gas, contrary to acetone, increased significantly the signal intensity and sensitivity and avoided the overlap of desired peaks. The LOD of device for acetamiprid pesticide was estimated to be 0.5 μg g^?1 and the LOQ of instrument was obtained as 1.66 μg g^?1. The calibration curve was in the dynamic range between 0.5–11.5 μg g^?1 and the Correlation Coefficient was 0.998. Also, the ion mobility and the reduced ion mobility were calculated for acetamiprid ion. After analysis of five samples with IMS instrument, the acetamiprid residue was determined and it turned out that it was under allowed limit in all three types of pistachio. In addition, the amount of acetamiprid residue was higher for Akbari type relative to Fandoghi and Kalachuchi ones. The reason for this observation is the higher vulnerability of Akbari trees to insects and pests and this in turn causes more pesticide to be consumed.     

Synthesis of <Emphasis Type=Italic>N</Emphasis>-hydroxy-imidamide-functionalized graphene: an efficient metal-free electrocatalyst for oxygen reduction

Metal-free electrocatalysts for oxygen reduction reaction (ORR) are key to the development of efficient, durable, and low-cost alternatives to noble-metal-based electrocatalysts in fuel cell cathodes. In recent years, many efforts are directed to the metal-free catalyst based on heteroatom-doped graphene. In this work, we demonstrate that the graphene surface can be converted into the catalyst for the oxygen reduction by chemical functionalization. In this context, we first synthesized malononitrile-functionalized graphene oxide. Amidoximation of nitrile group and reduction in graphene oxide were then carried out by hydroxylamine in one step. The electrochemical behavior of functionalized graphene-modified electrode for the reduction in oxygen was studied. The results showed that the electrocatalyst fabricated by this method exhibited striking catalytic activities in alkaline solution. In alkaline solution, this catalyst showed a competitive activity to the commercial Pt catalyst via four-electron transfer pathway with better ORR selectivity and stability. In addition, this metal-free electrocatalyst exhibited tolerance to methanol crossover effect. Based on its outstanding performance, this functionalized graphene electrocatalyst showed the promising prospect of a metal-free catalyst for fuel cell with much lower cost than currently used Pt/C catalyst.     

Resource allocation based on cost efficiency

In this paper, we consider a resource allocation (RA) problem and develop an approach based on cost (overall) efficiency. The aim is to allocate some inputs among decision making units (DMUs) in such way that their cost efficiencies improve or stay unchanged after RA. We formulate a multi-objective linear programming problem using two different strategies. First, we propose an RA model which keeps the cost efficiencies of units unchanged. This is done assuming fixed technical and allocative efficiencies. The approach is based on the assumption that the decision maker (DM) may not have big changes in the structure of DMUs within a short term. The second strategy does not impose any restrictions on technical and allocative efficiencies. It guarantees that none of the cost efficiencies of DMUs get worse after RA, and the improvement for units is possible if it is feasible and beneficial. Two numerical examples and an empirical illustration are also provided.     

Some extensions of the operator entropy type inequalities

In this paper, we define the generalised relative operator entropy and investigate some of its properties such as subadditivity and homogeneity. As application of our result, we obtain the information inequality. In continuation, we establish some reverses of the operator entropy inequalities under certain conditions by using the Mond–Pe?ari? method.     

Stabilization of active fault‐tolerant control systems by uncertain nonhomogeneous markovian jump models

This article investigates the stabilization and control problems for a general active fault‐tolerant control system (AFTCS) in a stochastic framework. The novelty of the research lies in utilizing uncertain nonhomogeneous Markovian structures to take account for the imperfect fault detection and diagnosis (FDD) algorithms of the AFTCS. The underlying AFTCS is supposed to be modeled by two random processes of Markov type; one characterizing the system fault process and the other describing the FDD process. It is assumed that the FDD algorithm is imperfect and provides inaccurate Markovian parameters for the FDD process. Specifically, it provides uncertain transition rates (TRs); the TRs that lie in an interval without any particular structures. This framework is more consistent with real‐world applications to accommodate different types of faults. It is more general than the previously developed AFTCSs because of eliminating the need for an accurate estimation of the fault process. To solve the stabilizability and the controller design problems of this AFTCS, the whole system is viewed as an uncertain nonhomogeneous Markovian jump linear system (NHMJLS) with time‐varying and uncertain specifications. Based on the multiple and stochastic Lyapunov function for the NHMJLS, first a sufficient condition is obtained to analyze the system stabilizability and then, the controller gains are synthesized. Unlike the previous fault‐tolerant controllers, the proposed robust controller only needs to access the FDD process, besides it is easily obtainable through the existing optimization techniques. It is successfully tested on a practical inverted pendulum controlled by a fault‐prone DC motor. © 2016 Wiley Periodicals, Inc. Complexity 21: 318–329, 2016