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1.
This paper uses the method of linear approximation for impulsive systems and gets a theorem which guarantees a fishery modei to be asymptotically stable at its equilibrium point and gives the ecological explanation. 相似文献
2.
The removal of heavy metal cations by natural zeolites 总被引:4,自引:0,他引:4
In this study, the adsorption behavior of natural (clinoptilolite) zeolites with respect to Co2+, Cu2+, Zn2+, and Mn2+ has been studied in order to consider its application to purity metal finishing wastewaters. The batch method has been employed, using metal concentrations in solution ranging from 100 to 400 mg/l. The percentage adsorption and distribution coefficients (Kd) were determined for the adsorption system as a function of sorbate concentration. In the ion exchange evaluation part of the study, it is determined that in every concentration range, adsorption ratios of clinoptilolite metal cations match to Langmuir, Freundlich, and Dubinin–Kaganer–Radushkevich (DKR) adsorption isotherm data, adding to that every cation exchange capacity metals has been calculated. It was found that the adsorption phenomena depend on charge density and hydrated ion diameter. According to the equilibrium studies, the selectivity sequence can be given as Co2+ > Cu2+ > Zn2+ > Mn2+. These results show that natural zeolites hold great potential to remove cationic heavy metal species from industrial wastewater. 相似文献
3.
Xiuhui He Zhaohong Su Qingji Xie Chao Chen Yingchun Fu Li Chen Ying Liu Ming Ma Le Deng Dilan Qin Yueping Luo Shouzhuo Yao 《Mikrochimica acta》2011,172(1-2):95-102
A simple, cheap, and nonpolluting method was developed for the cloud point extraction of gold (Au) and palladium (Pd). It is based on the complexation reaction of Au and Pd with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) and micelle mediated extraction of the complex using the non-ionic surfactant poly(ethylene glycol) mono-p-nonylphenyl ether (PONPE 7.5). Under the optimized experimental conditions, the enrichment factors are 16 and 17 for Au and Pd, respectively, for 15?mL of preconcentrated solution. The limits of detection are 3.8???g?L?1 and 1.8???g?L?1 for Au and Pd, respectively. The relative standard deviations are 1.4% for Au and 0.6% for Pd (n?=?11). The method was successfully applied to the determination of Au and Pd in certified reference materials and mine samples. Figure
CPE of gold(III) and palladium(II) 相似文献
4.
Dilan Chen Genke YangZhengzhi Han 《Communications in Nonlinear Science & Numerical Simulation》2012,17(7):2990-2996
In this paper, we consider the observer design for input-to-state stability (ISS) based synchronization of Lur’e differential inclusion system. A new impulsive observer is investigated to guarantee the error system remains bounded for any bounded disturbances. An example is employed to verify the feasibility of the designed observer. 相似文献
5.
Emin Karapinar 《Journal of inclusion phenomena and macrocyclic chemistry》2005,53(3):171-175
N′-(4′-Benzo[15-crown-5]naphthylaminoglyoxime (H2L) and its sodium chloride complex (H2L·NaCl) have been prepared from 2-naphthylchloroglyoxime, 4′-aminobenzo[15-crown-5] and sodium bicarbonate or sodium bicarbonate and sodium chloride. Nickel(II), cobalt(II) and copper(II) complexes of H2L and H2L·NaCl have a metal–ligand ratio of 1:2 and the ligand coordinates through the two N atoms, as do most of the vic-dioximes. The BF2+-capped Ni(II), Co(III) and mononuclear complexes of thevic-dioxime were prepared. The macrocyclic ligands and their transition metal complexes have been characterized on the basis of IR, 1H NMR spectroscopy and elemental analyses data. 相似文献
6.
Sample processing is a very important component of uncertainty in analytical results. In order to have reliable results, the laboratory sample should be properly processed to obtain statistically homogenous matrix—before the representative test portions are withdrawn for analysis. The use of 14C-labeled compound is preferable because the analyte can be quantified without cleanup. The method is based on surface treatment of cucumber with 14C-chlorpyrifos, determination of 14C-chlorpyrifos activity in the replicate test portions of different size, and determination of the uncertainty of sample processing. 相似文献
7.
Emin Karapinar 《Journal of inclusion phenomena and macrocyclic chemistry》2005,53(3-4):171-175
N′-(4′-Benzo[15-crown-5]naphthylaminoglyoxime (H2L) and its sodium chloride complex (H2L·NaCl) have been prepared from 2-naphthylchloroglyoxime, 4′-aminobenzo[15-crown-5] and sodium bicarbonate or sodium bicarbonate and sodium chloride. Nickel(II), cobalt(II) and copper(II) complexes of H2L and H2L·NaCl have a metal–ligand ratio of 1:2 and the ligand coordinates through the two N atoms, as do most of the vic-dioximes. The BF 2 + -capped Ni(II), Co(III) and mononuclear complexes of thevic-dioxime were prepared. The macrocyclic ligands and their transition metal complexes have been characterized on the basis of IR, 1H NMR spectroscopy and elemental analyses data. 相似文献
8.
Preparation of CTA-based polymer inclusion membrane using calix[4]arene derivative as a carrier for Cr(VI) transport 总被引:1,自引:0,他引:1
Ahmet Kaya Canan Onac Ahmet Surucu Emin Karapinar Hamza K. Alpoguz Begum Tabakci 《Journal of inclusion phenomena and macrocyclic chemistry》2014,79(1-2):103-111
In this work, the transport of Cr(VI) ions from an aqueous donor phase solution to an acceptor phase that contained an acetic acid/ammonium acetate buffer at pH 5 through a polymer inclusion membrane (PIM) containing p-tert-butylcalix[4]arene amine derivative as carrier was studied. The Cr(VI) passed through a PIM comprised of cellulose triacetate as a support and 2-NPOE as a plasticizer. The transport efficiency of Cr(VI) was studied under various experimental conditions, such as effect of carrier concentration, acceptor phase pH, type of plasticizer in the membrane, stirring rate and membrane thickness. The kinetic parameters were calculated as rate constant (k), permeability coefficient (P), and flux (J). The transport efficiency of Cr(VI) was observed to be 95.07 % after 10 h under optimized conditions. The prepared PIM was characterized with Fourier transform infrared spectroscopy and the atomic force microscopy techniques as well as with contact angle measurements. This is an effective method for the removal of Cr(VI) which is toxic for human body and environment from the waste water. 相似文献
9.
Ahmet Coşkun Emin Karapinar 《Journal of inclusion phenomena and macrocyclic chemistry》2008,60(1-2):59-64
4-(Chloroacetyl)diphenyl thioether (1) was synthesized from chloroacetyl chloride and diphenyl thioether in the presence of
AlCl3 as catalyst in a Friedel-Crafts reaction. Subsequently, its keto oxime (2) and glyoxime (3) derivatives were prepared. N-(4′-Benzo[15-crown-5]thiophenoxyphenylaminoglyoxime
(H2L) and its sodium chloride complex (H2L · NaCl) were prepared from 4-(thiophenoxy)chlorophenylglyoxime (3), 4′-aminobenzo[15-crown-5] and sodium bicarbonate or
sodium bicarbonate and sodium chloride. Ni(II), Co(II) and Cu(II) complexes of H2L and H2L · NaCl have a metal–ligand ratio of 1:2 and the ligand coordinates through the two N atoms, as do most of the vic-dioximes. The BF2-capped Ni(II) mononuclear complex of the vic-dioxime was prepared. The macrocyclic ligands and their transition metal complexes
were characterized on the basis of FT-IR, 1H NMR, 13C NMR spectroscopy and elemental analyses data. 相似文献
10.
Cem Yamali Feyza Sena Engin Sinan Bilginer Mehtap Tugrak Dilan Ozmen Ozgun Gulsen Ozli Serkan Levent Begum Nurpelin Saglik Yusuf Ozkay Halise Inci Gul 《Journal of heterocyclic chemistry》2021,58(1):161-171
Chalcones targeting neurodegenerative diseases have been known as attractive structures in drug design and discovery. In this study, phenothiazine-based chalcones as ChEs and MAOs inhibitors were designed and synthesized via base-catalyzed Claisen-Schmidt condensation, and chemical structures of the compounds were elucidated by NMRs and HRMS. Compounds 3 and 9 showed promising inhibition potency against AChE enzyme with IC50 values of 0.221 μM and 0.053 μM while compound 9 displayed remarkable inhibition potency toward MAO-B enzyme with IC50 value of 0.048 μM. Compound 9 , as a dual-target inhibitor, selectively inhibited AChE and MAO-B enzymes. This promising behavior is an advantage for the compound since MAO-B and AChE inhibition have a role in Alzheimer's disease. Fused tricyclic ring systems such as phenothiazine incorporated with chalcone moiety being multitargeting ligands may help scientists for the rational design of novel lead compounds targeting neurodegenerative illnesses. 相似文献