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排序方式: 共有158条查询结果,搜索用时 31 毫秒
31.
Niiket
cal Feray Aydoan idem Yolaan Zuhal Turgut 《Journal of heterocyclic chemistry》2003,40(4):721-724
Alkyl and aryl substituted furothiazolidine derivatives have been synthesized by the reaction of Wittig reagent with benzylidene derivatives of 4‐thiazolidinones obtained from aldimines and thioglicolic acid. 相似文献
32.
Turgut Gündüz Esma Kiliç Güleren Özkan Muhammed F. Awaad Mustafa Taştekin 《Analytica chimica acta》1990
Nineteen phenolic acids, namely phenol, 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2,5-dinitrophenol, 2,6-dinitrophenol, 2,4,6-trinitrophenol, 4-chlorophenol, 2,4,6-trichlorophenol, 1,2-dihydroxybenzene, 1,3-dihydroxybenzene, 1,4-dihydroxybenzene, 1,2,3-trihydroxybenzene, 2-aminophenol, 3-aminophenol, 4-aminophenol, 3-cresol and 4-cresol, were titrated conductimetrically and potentiometrically with triethylamine and tetrabutylammonium hydroxide in acetonitrile under a nitrogen atmosphere at 25°C. Most exhibited normal behaviour on titration with triethylamine, but only 2,4-dinitrophenol, 2,6-dinitrophenol and 2,4,6-trinitrophenol gave useful characteristic and stoichiometric conductimetric titration curves. None of the compounds gave a meaningful conductimetric titration curve on titration with tetrabutylammonium hydroxide, which is a much stronger base than triethylamine. With three exceptions, all compounds exhibited stoichiometric well shaped potentiometric titration curves. Potentiometric titration curves of the phenolic acids with tetrabutylammonium hydroxide in acetonitrile are very similar to those of strong acids obtained in aqueous media with strong bases. Acetonitrile is a suitable solvent for titrating some of the weak phenolic acids conductimetrically with triethylamine, and is an excellent medium for titrating them potentiometrically with tetrabutylammonium hydroxide under a nitrogen atmosphere at 25°C. 相似文献
33.
A. Turgut C. Sauter M. Chirtoc J. F. Henry S. Tavman I. Tavman J. Pelzl 《The European physical journal. Special topics》2008,153(1):349-352
We present a new application of a hot wire sensor for
simultaneous and independent measurement of thermal conductivity k and
diffusivity α of (nano)fluids, based on a hot wire thermal probe with ac
excitation and 3 ω lock-in detection. The theoretical modeling of imaginary
part of the signal yields the k value while the phase yields the α value. Due
to modulated heat flow in cylindrical geometry with a radius comparable to
the thermal diffusion length, the necessary sample quantity is kept very
low, typically 25μl. In the case of relative measurements, the
resolution is 0.1% in k and 0.3% in α. Measurements of water-based
Aerosil 200V nanofluids indicate that ultrasound treatment is more efficient
than high pressure dispersion method in enhancing their thermal parameters. 相似文献
34.
Turgut
Ak Asit Saha Sharanjeet Dhawan Abdul Hamid Kara 《Numerical Methods for Partial Differential Equations》2020,36(6):1234-1253
In this work, we have investigated Coriolis effect on oceanic flows in the equatorial region with the help of geophysical Korteweg–de Vries equation (GKdVE). First, Lie symmetries and conservation laws for the GKdVE have been studied. Later, we implement finite element method for numerical simulations. Propagation of nonlinear solitary structures, their interaction and advancement of solitons can be seen in the results so produced. Additionally, Gaussian initial condition and undular bore initial condition are also investigated. Results so obtained have been found in perfect agreement with the available results. Bifurcation analysis of the oceanic traveling wave of the GKdVE is presented depending on traveling wave velocity and Coriolis parameter. It is discerned that velocity of the traveling wave and Coriolis parameter affect significantly on the propagation of the nonlinear waves. 相似文献
35.
Nihan Nugay Turgut Nugay Joseph P. Kennedy 《Journal of polymer science. Part A, Polymer chemistry》2019,57(8):929-935
The synthesis of primary hydroxyl‐telechelic polyisobutylene, HOCH2‐PIB‐CH2OH, often yields product the number average terminal functionality ( ) of which is less than theoretical 2.0, typically = 1.75–1.95. Polyurethane (PU) prepared with such low‐cost imperfect PIB‐diols, unsurprisingly, exhibit poor overall properties. Herein we report that mechanical, rheological, and thermal properties of polyisobutylene‐based polyurethane (PIB‐PU) and PIB‐PU reinforced with organically modified montmorillonite (OmMMT) prepared with PIB‐diol of = 1.85 are significantly enhanced by glycerol. Specifically, we document that calculated minor amounts of glycerol substantially improves tensile strength, ultimate elongation, elastic modulus, toughness, rubbery plateau, flow temperature, creep, permanent set, rate of recovery after loading, and thermal properties of PIB‐PU and OmMMT‐reinforced PIB‐PU prepared with PIB‐diol of = 1.85. The observations are summarized and discussed in terms of chemistry, micromorphology, and viscoelasticity. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 929–935 相似文献
36.
Russian Journal of Organic Chemistry - In this study, substituted 2H-indazolo[2,1-b]phthalazine-1,6,11-triones, that may possess biological activity, have been synthesized via one-pot... 相似文献
37.
Two novel C2-symmetric optically active pyridine-15-crown-5 type ligands containing lipophilic chains at the stereogenic centres, macrocycles 5 and 6, were prepared from (S)-1,2-propanediol and (S)-3-aryloxy-1,2-propanediol for the enantiomeric recognition of amino acid ester derivatives. These novel macrocycles have been shown to be strong complexing agents for primary organic ammonium salts (with K values of up to 1363.5 M?1, ΔGo of up to 17.86 kJ mol?1 and a selectivity ratio of 80:20) by 1H NMR titration method. These macrocyclic host exhibited enantioselective binding towards the l-enantiomer of phenylalanine methyl ester hydrochloride with KL/KD up to 8.57 in CDCl3 containing 0.25% CD3OD. Experimental results have been detailed with molecular dynamic calculations at atomic level concerning the molecular recognition and discrimination properties of a chiral pyridino-15-crown-5. The binding free energies were calculated as ~?25 kJ mol?1. The results indicated that the host binds and discriminates valine salts better than phenylalanine salts. The molecular dynamics, MM/PBSA calculations are consistent with the 1H NMR results. 相似文献
38.
H. Ibrahim Ugras Ismet Basaran Turgut Kilic Umit Cakir 《Journal of heterocyclic chemistry》2006,43(6):1679-1684
A new macrocyclic ligand, L was synthesized using the high dilution condition with condensation of triethylene glycol diamine and terephtalaldehyde in ethanol. The obtained product, L was identified by FT‐IR, 1H‐NMR, 13C‐NMR and Mass spectroscopy. The extraction equilibrium constants were estimated using dichloromethane/water membranes transfer with ICP‐AES and AES spectroscopy. Biological studies of this compound was determinated with disc diffusion method. The biological activity results showed that the synthesized ligand L has high activity against the studied microorganisms and high complexation ability against the Fe2+ cation. 相似文献
39.
Yu G Durduran T Zhou C Zhu TC Finlay JC Busch TM Malkowicz SB Hahn SM Yodh AG 《Photochemistry and photobiology》2006,82(5):1279-1284
Photodynamic therapy (PDT) requires oxygen to cause cellular and vascular tumor damage. Tissue oxygen concentration, in turn, is influenced by blood flow and blood oxygenation. Real-time clinical measurement of these hemodynamic quantities, however, is rare. This paper reports the development and application of a probe, combining diffuse reflectance spectroscopy (DRS) for measurement of tumor blood oxygenation and diffuse correlation spectroscopy (DCS) for measurement of tumor blood flow. The instrument was adapted for clinical use during interstitial prostate PDT. Three patients with locally recurrent prostate cancer received 2 mg/ kg motexafin lutetium (MLu) 3 h before illumination and a total light dose of 100 J/cm(2) at 150 mW/cm. Prostrate blood oxygen saturation (StO2) decreased only slightly (approximately 3%) after treatment. On the other hand, prostate blood flow and total hemoglobin concentration over the course of PDT decreased by 50% and 15%, respectively, suggesting MLu-mediated PDT has an anti-vascular effect. While it is certainly impossible to draw definite conclusions from measurements of only three patients, the observed differences in tumor blood flow and blood oxygenation responses during PDT can, in principle, be used to choose among tissue oxygen consumption models and therefore emphasize the potential clinical value for simultaneous monitoring of both parameters. 相似文献
40.
Melih Turgut 《International Journal of Mathematical Education in Science & Technology》2018,49(8):1181-1202
In this work, students’ thinking modes and representation types in linear algebra are investigated through statistical implicative analysis techniques. Specifically, our research question considers the implicative relationships between students’ thinking modes and representation types of linear algebra. The participants were 74 undergraduate linear algebra students enrolled in the department of mathematics education of a government university located in western Turkey. The data was collected using six paper-and-pencil tasks, relating to a context of linear equations, matrix algebra, linear combination, span, linear independency–dependency and basis. A document analysis technique was used to analyze the data within a theoretical lens of thinking modes and representation types. To delineate similarity diagrams, hierarchical trees, and implicative models (which will be detailed in the paper), an R version of Cohesion Hierarchical Implicative Classification software was used. According to the results, students’ analytic structural thinking modes on linear combination and span and linear independency significantly imply the use of algebraic and abstract representations. The results also confirm that the notions of linear combination and span and linear dependency/independency are core elements for theoretical thinking and are needed for learning linear algebra. 相似文献