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排序方式: 共有419条查询结果,搜索用时 15 毫秒
81.
Tahir SAVRAN Abdurrahman KARAG
Z ükriye Nihan KARUK ELMAS Duygu AYDIN Furkan
ZEN Kenan KORAN Fatma Nur ARSLAN Ahmet Orhan G
RGÜLÜ brahim YILMAZ 《Turkish Journal of Chemistry》2020,44(4):1148
A fluorogenic probe based on a coumarin-derivative for Cu2+ sensing in CH3CN/H2O media (v/v, 95/5, 5.0 μM) was developed and applied in real samples. 3-(4-chlorophenyl)-6,7-dihydroxy-coumarin (MCPC) probe was obtained by synthetic methodologies and identified by spectral techniques. The probe MCPC showed remarkable changes with a “turn-off” fluorogenic sensing approach for the monitoring of Cu2+ at 456 nm under an excitation wavelength of 366 nm. The response time of the probe MCPC was founded as only 1 min. The detection limit of the probe MCPC was recorded to be 1.47 nM. The binding constant and possible stoichiometric ratio (1:1) values were determined by Benesi-Hildebrand and Job’s plot systems, respectively. The mechanism of the probe MCPC with Cu2+ was further confirmed by ESI-MS and FT-IR analyses, as well as supported by theoretical calculations. Furthermore, the probe MCPC was successfully employed for the practical applications to sense Cu2+ in different herbal and black tea samples. The proposed sensing method was also verified by ICP-OES method. 相似文献
82.
Orhan ?çelli Salih Erzeneogˇlu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2006,97(1):34-40
Ncoh/NComp and NKβ/NKα intensity ratios of scattered photons by Zn in the linear region and the infinite mass thickness region are measured as functions of the pressure used for compressing the pellets with a Si(Li) detector using Am-241 and Fe-55 annular source. Besides, the effect on the experimental intensity ratio of relation between two different thicknesses of sample with applied different pressures on the sample is investigated in this study. Harmony between the linear and infinitive (critical) thickness region and the applied pressure on the sample has directly affected the experimental intensity ratios. Experimental results were not compared with various theoretical values in the literature, for present results constitute the first experimental measurements. 相似文献
83.
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
84.
Experimental and simulated data for adsorption of gas mixtures on energetically heterogeneous surfaces like activated carbon and zeolites exhibit negative deviations from ideality. The deviations are large in some cases, with activity coefficients at infinite dilution equal to 0.1 or less. Similar molecules form ideal mixtures, but molecules of different size or polarity are nonideal. Equations for bulk liquid mixtures (Wilson, Margules, etc.) do not apply to isobars for adsorbed mixtures. A two-constant equation for activity coefficients as a function of composition and spreading pressure is in good agreement with theory, simulation, and experiment. 相似文献
85.
Erkan Yilmaz Yıldız Tut Orhan Turkoglu Mustafa Soylak 《Journal of the Iranian Chemical Society》2018,15(8):1721-1731
In this study, Pd nanoparticle-modified magnetic Sm2O3–ZrO2 material (Pd–Fe3O4–Sm2O3–ZrO2) as multifunctional catalyst was fabricated and used for catalytic reduction of 2-nitrophenol compound, degradation of methylene blue and rhodamine B dyes, which are toxic pollutants. The magnetic material was used for the first time as a catalyst for the reduction and degradation studies. Pd nanoparticle-modified magnetic Sm2O3–ZrO2 catalyst was prepared using the deposition–precipitation methods and were characterized by X-ray diffraction, scanning electron microscopy, atomic absorption spectrometry, Raman spectroscopy and BET surface analyzer. The Pd nanoparticle-modified magnetic Sm2O3–ZrO2 material can lead to high catalytic activity for the reduction of 2-nitrophenol and degradation of rhodamine B and methylene blue with >?95% conversion within ~?2 and 80 s even when the content of Pd in it is as low as 5.8 wt%. 相似文献
86.
Statistical Limit Superior and Limit Inferior 总被引:4,自引:0,他引:4
Following the concept of statistical convergence and statistical cluster points of a sequence , we give a definition of statistical limit superior and inferior which yields natural relationships among these ideas: e.g., is statistically convergent if and only if . The statistical core of is also introduced, for which an analogue of Knopp's Core Theorem is proved. Also, it is proved that a bounded sequence that is -summable to its statistical limit superior is statistically convergent.
87.
Mustafa Tombul Kutalmis Guven Orhan Büyükgüngr Huseyin Aktas Tahsin Nuri Durlu 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(9):m430-m432
In the title compound, poly[(μ3‐boric acid)‐μ4‐maleato‐dipotassium], [K2(C4H2O4){B(OH)3}]n, there are two independent K+ cations, one bonded to seven O atoms (three from boric acid and four from maleate), and the other eight‐coordinate via three boric acid and four maleate O atoms and a weak η1‐type coordination to the C=C bond of the maleate central C atoms. Hydrogen bonding links the boric acid ligands and maleate dianions, completing the packing structure. 相似文献
88.
89.
Ismail Ercan Filiz Ercan Cengiz Arc Orhan Atakol 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):m137-m138
A new tetranuclear CuII–HgII–HgII–CuII complex, [Cu2Hg2Cl4(C18H18N2O2)2], has been prepared by means of a copper complex found in the literature. The molecular structure of this complex was determined by X‐ray diffraction and the Cu–Hg–Hg–Cu chain was seen to be non‐linear. The change in magnetic susceptibility with temperature was recorded for this complex and observed to abide by the Curie–Weiss law. The coordination around the HgII ions is square pyramidal. The Cu?Hg bridging distance is 3.5269 (7) Å. 相似文献
90.
A comparative study on the efficiency of some tungsten containing chemical modifiers such as W, W+Pd, W+Rh, W+Pt and W+Ru
for thermal stabilization of Bi, In, Pb and Sb has been performed systematically by a Zeeman electrothermal atomization atomic
absorption spectrometer (ETAAS). The addition of tartaric acid (TA) as a reducing agent additionally to the mixed modifiers
was studied. A mixture of W+Pd+TA was found to be a powerful mixed modifier for the determination of Bi, In, Pb and Sb. Pretreatment
temperatures could be increased up to 1250–1500° C using this mixed modifier. The use of the mixed modifier results in an
enhanced accuracy and precision of the method and recovery rates above 97% for all samples. The W+Pd+TA mixed modifier was
applied to the determination of Bi and Pb in dissolved geological reference samples.
Received: 14 March 1996 / Revised: 3 June 1996 / Accepted: 30 June 1996 相似文献