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51.
Gürsoy Süleyman Koçak Makbule Cihan Ali Gül Ahmet Bekaroğlu Özer 《Transition Metal Chemistry》2000,25(4):474-477
A new soluble vic-dioxime ligand namely 1,4-bis(2′-hydroxyethyl)-2,3-bis(hydroxyimino)-5,6-diphenylpiperazine, (LH2) containing optically active centers has been prepared as a mixture of isomers from (CNO)2 and N,N-bis(2-hydroxyethyl)stilbendiamine (1) which has been made by the reduction of the condensation of the product of benzaldehyde and 2-aminoethanol in the presence
of aluminum amalgam. N,N-coordinated planar metal complexes of this ligand have been synthesized with NiII, CuII, CoII, PdII and UVIO2. Oxidation of (LH)2Co in the presence of a base, such as pyridine, leads to an octahedral complex (LH)2CopyCl containing pyridine and chloride as axial ligands in addition to vic-dioxime ligands. The structures of the ligand and its complexes are proposed on the basis of elemental analysis, 1H-n.m.r., mass, i.r. and u.v.–vis. spectral data.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
52.
Matías Bejide Patricio Contreras Pia Homm Boris Duran Jos Antonio García-Merino Andreas Rosenkranz Juliano C. Denardin Rodrigo del Río Samuel A. Hevia 《Molecules (Basel, Switzerland)》2020,25(22)
Nickel nanopillar arrays were electrodeposited onto silicon substrates using porous alumina membranes as a template. The characterization of the samples was done by scanning electron microscopy, X-ray diffraction, and alternating force gradient magnetometry. Ni nanostructures were directly grown on Si by galvanostatic and potentiostatic electrodeposition techniques in three remarkable charge transfer configurations. Differences in the growth mechanisms of the nanopillars were observed, depending on the deposition method. A high correlation between the height of the nanopillars and the charge synthesis was observed irrespective of the electrochemical technique. The magnetization measurements demonstrated a main dependence with the height of the nanopillars. The synthesis of Ni nanosystems with a controllable aspect ratio provides an effective way to produce well-ordered networks for wide scientific applications. 相似文献
53.
K. Asokan C.L. Dong H.M. Tsai C.L. Chang P. Duran O. Peña 《Solid State Communications》2005,134(12):821-826
Electronic structures of orthorhombic perovskite-type manganites (OM) and hexagonal manganites (HM) are compared by using X-ray absorption near edge structure spectroscopy. This study reveals that the environments around Mn and O ions in both the systems are different. These are reflected primarily in the lifting of degeneracy of the Mn 3d orbitals. Interestingly, the unoccupied Mn 3dx2−y2 orbital in HM is strongly hybridized with O 2p states and appears to be responsible for both long range orderings: ferroelectric ordering at high temperatures and ferromagnetic ordering at low temperatures. 相似文献
54.
In the present paper we prove a Korovkin type approximation theorem for a sequence of positive linear operators acting from
a weighted space Cρ1 into a weighted space Bρ2 with the use of a matrix summability method which includes both convergence and almost convergence. We also study the rates
of convergence of these operators. 相似文献
55.
Mustafa Imamoglu Asuman Ozturk Şeyma Aydın Aynur Manzak Ali Gündoğdu Celal Duran 《Journal of Dispersion Science and Technology》2018,39(8):1144-1148
Hazelnut husk (HH), an agricultural waste, was converted to carbonaceous material by chemical activation using potassium acetate. The produced activated carbon (KAHHAC) was characterized by FTIR, SEM, N2 adsorption–desorption experiments, CHN elemental analysis, and determination of moisture, ash, and point of zero charge. KAHHAC was used for the batch adsorption of Cu(II) ions from aqueous solutions. Optimum pH and contact time were found to be 5.0 and 240 minutes, respectively. The adsorption equilibrium data were described well by the Langmuir equation providing 105.3?mg?g?1 Cu(II) adsorption capacity. The pseudo-second-order model successfully described the kinetic of Cu(II) adsorption by KAHHAC. The adsorbed Cu(II) onto KAHHAC was completely desorbed by 0.5?M nitric acid. In conclusion, HH activated carbon (AC) produced by the potassium acetate activation method is a very useful and efficient sorbent material for the removal of Cu(II) from aqueous solution. 相似文献
56.
Hevia S. A. Bejide M. Duran B. Rosenkranz A. Ruiz H. M. Favre M. del Rio R. 《Journal of Solid State Electrochemistry》2018,22(9):2845-2853
Journal of Solid State Electrochemistry - The electrochemical response of thin non-doped diamond-like carbon films grown by pulsed laser deposition onto n-type (P-doped) silicon substrates was... 相似文献
57.
Zekeriyya Bahadır Volkan Numan Bulut Arif Mermer Neslihan Demirbaş Celal Duran Mustafa Soylak 《Journal of the Iranian Chemical Society》2018,15(6):1347-1354
A selective separation and preconcentration method for the determination of gold ions in water and ore samples has been developed using dispersive liquid–liquid microextraction, followed by flame atomic absorption spectrometry. 4-Ethyl-1(2-(4-(4-nitrophenyl)piperazin-1-yl)acetyl)thiosemicarbazide) (NPPTSC) has been used for the first time as new chelating reagent. A mixture of ethanol (dispersive solvent) and carbon tetrachloride (extraction solvent) was used. Some parameters affecting the extraction procedure including the type and volume of the extracting and dispersive solvents, HNO3 concentration, the chelating agent amount, volume of sample, and foreign ions have optimized. Also, the complex formation between gold ions and the ligand has been investigated in a methanol–water solution (1:1) using UV–visible spectrometry. The spectrophotometric titration data showed that of Au–NPPTSC complex composition was found to be 3:2. After optimizing the instrumental and experimental parameters, we achieved a detection limit of 1.5 µg L?1, a preconcentration factor of 50, and a linear dynamic range of 10.0–400.0 µg L?1. The relative standard deviation obtained 2.1% at 50 µg L?1 for gold ions (n = 10). The proposed method was successfully performed for the determination of gold in certified reference material, environmental water, and ore samples. 相似文献
58.
Cihan Topcu Gamze Lacin Vedat Yilmaz Fatih Coldur Bulent Caglar Osman Cubuk 《Analytical letters》2018,51(12):1890-1910
A novel copper(II)-selective electrode based on graphite oxide/imprinted polymer composite was developed for the electrochemical monitoring of copper(II) (Cu2+) ions. The electrode exhibited highly selective potentiometric response to Cu2+ with respect to common alkaline, alkaline earth and heavy metal cations. The composite composition studies indicated that the most suitable composite composition performing the most promising potentiometric properties was 20.0% ionophore (Cu2+-ion imprinted polymer), 10.0% paraffin oil, 5.0% multiwalled carbon nanotubes, and 65.0% graphite oxide. The fabricated electrode exhibited a linear response to Cu2+ over the concentration range of 1.0?×?10??6–1.0?×?10??1?M (correlation coefficient of 0.9998) with a sensitivity of 26.1?±?0.9?mV decade??1. The detection limit of the fabricated electrode was determined to be 4.0?×?10??7?M. The electrode worked well in the pH range of 4.0–8.0. The electrode had stable, reversible and fast potentiometric response (3?s). In addition, the electrode had a lifetime of more than 1 year. The analytical applications of the proposed electrode were performed using as an indicator electrode for the potentiometric titration of Cu2+ with ethylene diamine tetraacetic acid solution and for the determination of Cu2+ of spiked river, dam, and tap water samples. The obtained results for potentiometric titration and water samples were satisfactory. 相似文献
59.
A. J. Duran 《Constructive Approximation》1997,13(2):271-286
A technique to find the asymptotic behavior of the ratio between a polynomialss
n and thenth orthonormal polynomial with respect to a positive measureμ is shown. Using it, some new results are found and a very simple proof for other classics is given. 相似文献
60.
Logan JL Masse P Gnanou Y Taton D Duran RS 《Langmuir : the ACS journal of surfaces and colloids》2005,21(16):7380-7389
Star diblock copolymers containing polystyrene (PS) and poly(ethylene oxide) (PEO) were investigated as surface films at the air/water interface. Both classic and dendritic-like stars were prepared containing either a PS core and PEO corona or the reverse. The investigated polymers, consisting of systematic variations in architectures and compositions, were spread at the air/water interface, generating reproducible surface pressure-area isotherms. All of the films could be compressed to higher pressures than would be possible for pure PEO. For stars containing 20% or more PEO, three distinct regions appeared. At higher areas, the PEO absorbs in pancakelike structures at the interface with PS globules sitting atop. Upon compression, a pseudoplateau transition region appeared. Both regions strongly depended on PEO composition. The pancake area and the pseudoplateau width and pressure increased in a linear fashion with an increasing amount of PEO. In addition, minimum limits of PEO chain length and mass percentage were determined for observing a pseudoplateau. At small areas, the film proved less compressible, producing a rigid film in which PS dominated. Here, the film area increased with both molecular weight and the amount of PS. Comparison with pure linear PS showed the stars spread more, occupying greater areas. Among the stars, the PEO-core stars were more compact while the PS-core stars spread more. The influence of architecture in terms of the core/corona polymers and branching were also examined. The effects of architecture were subtle, proving less important than PEO chain length or mass percentage. 相似文献