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81.
Keltouma Nouri Mohamed Feham Saliha Dali 《International Journal of Infrared and Millimeter Waves》2005,26(12):1727-1739
The integral equations technique based on a three dimensional finite element method is applied as a quick and accurate analysis
tool for the design of microwave passband filters. A three resonator H-plane bandpass filters with the various shapes of cavities
and the irises are analyzed with this method in a single step and for only one mode, take into account all the electromagnetic
effects. Consequently, it consumes less memory and CPU time.
We propose also to study the same filters filled by homogeneous high dielectric material (ετ = 9.6) for Both resonator and coupling section.
All these numerical results have been validated through a comparison with the results available in the scientific literature. 相似文献
82.
A chemiluminescence (CL) flow system for determination of thyroxine (Thy) is presented. It is based on the catalytic effect of cobalt(II) on the CL reaction between luminol and hydrogen peroxide. The iodinated chemical structure of Thy causes a heavy atom effect. The luminol CL signals show significant quenching by Thy. The calibration graph for Thy is linear for 15-70 μg ml−1 and the 3σ detection limits are 27 μg ml−1 for d-Thy and 23 μg ml−1 for l-Thy. 相似文献
83.
Tuncer Hkelek Nurcan Akduran Saliha Bege Adem Kl Zeynel Kl 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1404-1406
The title compound, C45H55NO6P2, consists of an acyclic P=N—P(O) monophosphazene chain and five bulky 2,4,6‐trimethylphenoxy side groups which predominantly determine the molecular shape. Although the P—N single [1.586 (3) Å] and P=N double [1.517 (3) Å] bonds are significantly different from each other, both are substantially shorter than the ideal P—N single bond. The P—N—P angle [146.0 (2)°] corresponds to the upper limit reported for acyclic phosphazene derivatives in the literature. 相似文献
84.
Hexakis(2‐formylphenoxy)cyclotri‐phosphazene ( 2 ) was obtained from the reaction of hexachlorocylotriphosphazene ( 1 ) with 2‐hydroxy‐benzaldehyde. Hexakis(2‐[(hydroxyimino)methyl]‐phenoxy)cyclotriphosphazene (3) was synthesized from the reaction of 2 with hydroxlaminehydrochloride in pyridine. Hexasubstituted compounds 4, 5, 6, 8, 9 , and 10 were obtained from the reactions of 3 with methyl iodide, ethyl bromide, allyl bromide, propanoyl chloride, benzoyl chloride, and 4‐methoxybenzoyl chloride, respectively. Disubstituted product 7 was obtained from the reaction of 3 with chloroacetyl chloride. Pure and defined products could not be obtained from the reaction of 3 with acetyl chloride, benzyl chloride, and 2‐chlorobenzoyl chloride. The compounds were characterized by elemental analysis and IR, 1H, 13C, and 31P NMR spectroscopy. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:791–797, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20350 相似文献
85.
Elmas Irmak 《Topology》2004,43(3):513-541
Let S be a closed, connected, orientable surface of genus at least 3, be the complex of curves on S and be the extended mapping class group of S. We prove that a simplicial map, , preserves nondisjointness (i.e. if α and β are two vertices in and i(α,β)≠0, then i(λ(α),λ(β))≠0) iff it is induced by a homeomorphism of S. As a corollary, we prove that if K is a finite index subgroup of and is an injective homomorphism, then f is induced by a homeomorphism of S and f has a unique extension to an automorphism of . 相似文献
86.
We describe a method for the determination of thyroxine (Thy) using its quenching effect on Eu(PDA)3
3- tris complex fluorescence. The relative fluorescence intensities are measured at fixed exc = 282 nm, em = 615 nm by titrating the metal complex with Thy in piperazine buffer solution at pH 6.5. Data indicated an associative type of reaction of two molecules valid between 0.0 < R < 1.0, R being the mole ratio of Eu(PDA)3
3- to Thy. Over this ratio and up to (R 1.0) collisional quenching of Eu(PDA)3
3- complex ion emission is seen as a result of heavy atom effect, intermolecular energy transfer playing the main role. This is also confirmed by the Stern-Volmer equation. In optimized experimental conditions, the L- form of Thy is determined in a range of 15.5–551.6 g/ml (2.0 × 10–5 – 7.1 × 10–4
M) with relative error of ±1.17%. 相似文献
87.
ükriye Nihan Karuk Elmas Ibrahim Berk Gunay Abdurrahman Karagoz Aykut Bostanci Gkhan Sadi Ibrahim Yilmaz 《Electroanalysis》2020,32(4):775-780
The selective and sensitive detection of biothiols; cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) in aqueous solutions is of considerable importance because of their pivotal roles in maintaining the reducing environment in the cells. This study describes a strategy for the determination of biothiols based on the PDI/Met‐Hg2+complex platform. We designed and fabricated methionine modified perylene diimide molecule as a selective sensing probe for Hg2+ ions in aqueous solutions ( PDI/Met‐Hg 2+). The complex between perylene bisimide derivative ( PDI/Met) and Hg2+ was investigated and it demonstrated turn‐on fluorescence response for the detection of the biological thiols. Besides, PDI/Met displayed fluorescence quenching response in the presence of mercury ions and the emission intensity of PDI/Met‐Hg2+ was recovered after transferring biothiols (Cys, Hcy, and GSH). Thus, PDI/Met could be utilized as a fluorescent chemosensor for the sequential recognition of mercury ions and biological thiols. 相似文献
88.
Elmas B Tuncel M Senel S Patir S Tuncel A 《Journal of colloid and interface science》2007,313(1):174-183
N-isopropylacrylamide (NIPA) based uniform thermosensitive microgels were synthesized by dispersion polymerization by using relatively hydrophilic crosslinking agents with hydroxyl functionality. Glycerol dimethacrylate (GDMA), pentaerythritol triacrylate (PETA) and pentaerythritol propoxylate triacrylate (PEPTA) were used as crosslinking agents with different hydrophilicities. A protocol was first proposed to determine the crosslinking density distribution in the thermosensitive microgel particles by confocal laser scanning microscopy (CLSM). The microgels were fluorescently labeled by using hydroxyl group of the crosslinking agent. The CLSM observations performed with the microgels synthesized by three different crosslinking agents showed that the crosslinking density exhibited a quadratic decrease with the increasing radial distance in the spherical microgel particles. This structure led to the formation of more loose gel structure on the particle surface with respect to the center. Then the use of hydrophilic crosslinking agents in the dispersion polymerization of NIPA made possible the synthesis of thermosensitive microgels carrying long, flexible and chemically derivatizable (i.e., hydroxyl functionalized) fringes on the surface by a single-stage dispersion polymerization. The microgels with all crosslinking agents exhibited volume phase transition with the increasing temperature. The microgel obtained by the most hydrophilic crosslinking agent, GDMA exhibited higher hydrodynamic diameters in the fully swollen form at low temperatures than those obtained by PETA and PEPTA. Higher hydrodynamic size decrease from fully swollen form to the fully shrunken form was also observed with the same microgel. 相似文献
89.
Saliha Bouhroum Francoise Arnaud-Neu Zouhair Asfari Jacques Vicens 《Supramolecular chemistry》2013,25(8):629-635
Tetra(diethyl)amide-p-tert-butylthiacalix[4]arene 1a in the cone conformation was synthesized and its binding properties towards a large variety of metal ions were established on the basis of liquid–liquid and solid–liquid extraction as well as complexation experiments. This compound is a less efficient and selective compound than the “classical” tetra(diethyl)amide-p-tert-butylcalix[4]arene 3 in the cone conformation for alkali and alkaline earth metal ions. However, Pb2+ is selectively extracted and complexed within heavy and transition metal ions. 相似文献