Showing papers by "Henan Normal University published in 2008"
TL;DR: In this article, a facile one-pot hydrothermal method assisted by sodium alginate was used to extract 3D Ag/ZnO hollow microspheres with different contents.
Abstract: In this paper, three-dimensional (3D) Ag/ZnO hollow microspheres with different Ag contents were prepared through a facile one-pot hydrothermal method assisted by sodium alginate The samples were structurally characterized by X-ray diffraction, field emission scanning electron microscope, high resolution transmission electron microscope, and X-ray photoelectron spectroscopy It was shown that all samples were composed of metallic Ag and wurtzite ZnO; the 3D Ag/ZnO hollow microspheres were constructed from self-assembled 1D Ag/ZnO nanorods; the surface O species can be categorized to surface hydroxyl oxygen (OH) and crystal lattice oxygen (OL), and the ratio between them varies with different Ag loadings The photocatalytic performance for the degradation of Orange G was also evaluated The results show that such hierarchical Ag/ZnO hollow microspheres exhibit significantly enhanced photocatalytic efficiency Investigation of the relationship of photoluminescence (PL) spectra and surface structure of the
332 citations
TL;DR: Results obtained indicated that this system could be tuned to a great extent because ionic liquids can be designable and the method does not suffer from the limitations of that in conventional solvent micro-extraction.
297 citations
TL;DR: It was found that both the nanosized anatase structure and the appearance of new absorption band in the visible region caused by nitrogen doping were responsible for the significant enhancement of OG degradation under visible light.
275 citations
TL;DR: This proposed method was successfully applied in the analysis of four real environmental water samples and good spiked recoveries were obtained, indicating that temperature-controlled ionic liquid dispersive liquid-phase microextraction had excellent application prospect in environmental field.
237 citations
TL;DR: Aqueous solutions of five ionic liquids (ILs) of the 1-n-alkyl-3-methylimidazolium bromide family, [C(n)mim]Br, were investigated by NMR measurements at 298.2 K as a function of IL concentrations and it was found that the ionic hydration and the cation-anion association or aggregation of the ILs offset each other.
Abstract: Aqueous solutions of five ionic liquids (ILs) of the 1-n-alkyl-3-methylimidazolium bromide family, [C(n)mim]Br (n = 4, 6, 8, 10, 12), were investigated by NMR measurements at 298.2 K as a function of IL concentrations. Critical aggregation concentrations and aggregation numbers of these ILs were determined by 1H NMR except for [C4mim]Br in D2O. The effects of the alkyl chain length of the cations were examined on the aggregation behavior of the ILs. 1H NMR data of the solvent D2O were used to investigate the hydration of the ILs in D2O, and it was found that the ionic hydration and the cation-anion association or aggregation of the ILs offset each other. The microenvironment of different protons of cations of the ILs in the aggregates was probed by determining the spin-lattice relaxation rate (1/T1). It is suggested that the imidazolium rings in the aggregates are exposed to water and that the molecular motion of the aggregates is more restricted than that of the monomers of the ILs. Furthermore, a stair-like microscopic aggregation structure is suggested for the [C(n)mim]Br/D2O (n = 6, 8, 10) systems from 2-D 1H-1H NOESY measurements.
230 citations
TL;DR: It is found that both nature of the anions and ring type of the cations significantly affect the aggregation in aqueous solution.
Abstract: The formation of ionic liquids aggregates in aqueous solution is of great importance to the future applications of ionic liquids. In this work, aggregation behavior of 1-alkyl-3-methylimidazolium salts [C8mim]X (X = Cl, Br, [NO3], [CH3COO], [CF3COO], [CF3SO3], and [ClO4]), 1-octyl-4-methylpyridinium bromide (4m-[C8pyr]Br), and 1-methyl-1-octylpyrrolidinium ([C8mpyrr]Br) has been investigated in aqueous solutions by conductivity, volume, fluorescence, dynamic light scattering, and transmission electron microscopy. The critical aggregation concentration (CAC), ionization degree of the aggregates alpha, the standard Gibbs energy of aggregation deltaG(m)degrees, the average aggregation number N, the apparent molar volumes at critical aggregation concentration V(phi,CAC), the apparent molar volumes in aggregation phase V(phi)mic, and the change of the apparent molar volumes upon aggregation deltaV(phi,m), have been derived from the experimental data for these ionic liquids. It is found that both nature of the anions and ring type of the cations significantly affect the aggregation in aqueous solution. The anionic effect basically follows the Hofmeister series, and the ability of anionic hydration is predominant for the aggregation behavior of the ionic liquids. Hydrophobicity and steric hindrance of the cations as well as binding strength of the cations with the anions are suggested to play important roles in the aggregation of [C8mim]Br, 4m-[C8pyr]Br, and [C8mpyrr]Br. The investigated ILs were found to form spherical aggregates. Structures of anions and cations have very weak effects on the morphology, but they do affect the aggregate sizes.
215 citations
TL;DR: In this paper, the suitability of imidazolium-based ionic liquids (ILs), 1-methyl-3-alkylimidazolate hexafluorophosphate [Cnmim][PF6] (n = 4, 6, 8) and 1-methy-3 -alkylindazolate tetrafluoroborate (BF4) for liquid-liquid extraction of selected endocrine-disrupting phenols from aqueous solutions was investigated.
197 citations
TL;DR: It was shown that the added tyrosine served both as a shape conductor for the formation of ZnO faceted nanorods and as a reducing agent of Ag(+) ions.
Abstract: In this paper, Ag/ZnO metal-semiconductor nanocomposites were prepared through a facile one-pot hydrothermal method with the assistance of tyrosine. The synthesized samples were structurally characterized by x-ray diffraction, scanning electron microscope, transmission electron microscope and x-ray photoelectron spectroscopy. It was shown that the added tyrosine served both as a shape conductor for the formation of ZnO faceted nanorods and as a reducing agent of Ag(+) ions. In the reaction process, the complexation of Ag(+) with NH(3) and OH(-) decreased the redox potential of Ag(+)/Ag, which prevented the formation of isolated Ag nanoparticles in solution. The prepared Ag/ZnO nanocomposites showed potential applications in photodegradation of organic dye pollutants and destruction of bacteria.
189 citations
TL;DR: The ligand-binding properties and the unusual tissue expression of odorant-binding protein 22 from the repertoire of Aedes aegypti suggest an additional function for this protein as pheromone carrier, analogously to vertebrates' urinary and salivary proteins as well as some insect chemosensory proteins.
123 citations
TL;DR: In this article, the analytical performances of the bismuth-modified zeolite doped carbon paste electrode (BiF-ZDCPE) for trace Cd and Pb analysis were investigated.
111 citations
TL;DR: The dispute about the intermolecular hydrogen bond cleavage or strengthening in the electronically excited-state of coumarin 102 chromophore in hydrogen donating solvents has been clarified by studies.
Abstract: The time-dependent density functional theory method was performed to investigate the electronically excited states of the hydrogen-bonded complex formed by coumarin 102 (C102) chromophore and the hydrogen-donating aniline solvent. At the same time, the electronic excited-state hydrogen-bonding dynamics for the photoexcited C102 chromophore in solution was also reconsidered. We demonstrated that the intermolecular hydrogen bond C═O···H—N between C102 and aniline molecules is significantly strengthened in the electronically excited-state upon photoexcitation, since the calculated hydrogen bond energy increases from 25.96 kJ/mol in the ground state to 37.27 kJ/mol in the electronically excited state. Furthermore, the infrared spectra of the hydrogen-bonded C102−aniline complex in both the ground state and the electronically excited state were also calculated. The hydrogen bond strengthening in the electronically excited-state was confirmed for the first time by monitoring the spectral shift of the stretching...
TL;DR: The results showed that the acute exposure of aqueous ionic liquid could cause damage to mouse, leading to antioxidant responses in livers of the treated mice, including an increase in hepatosomatic index and decrease in liver protein content.
TL;DR: Strong convergence for Mann and Ishikawa iterates of multivalued nonexpansive mapping T under some appropriate conditions is shown, which revises a gap in Panyanak's open question.
Abstract: We show strong convergence for Mann and Ishikawa iterates of multivalued nonexpansive mapping T under some appropriate conditions, which revises a gap in Panyanak [B. Panyanak, Mann and Ishikawa iterative processes for multivalued mappings in Banach spaces, Comput. Math. Appl. 54 (2007) 872-877]. Furthermore, we also give an affirmative answer to Panyanak's open question.
TL;DR: In this article, the BESII detector at center-of-mass energies between 3.7 and 5.0 GeV is fitted to determine resonance parameters (mass, total width, electron width) of the high mass charmonium states.
TL;DR: The experimental results indicated solar photo-Fenton process has more advantages compared with classical Fenton process, such as higher oxidation power, wider working pH range, lower ferrous ion usage, etc.
TL;DR: It is shown that saturation recovery from infective individuals leads to vital dynamics, such as bistability and periodicity, when the basic reproduction number R(0) is less than unity.
TL;DR: A photochemical active triangle terarylene was synthesized and the photochromic behavior was investigated, finding suppressed photoactivity of the oxidation state was attributed to the stronger intramolecular hydrogen bonding interactions.
TL;DR: In this article, the effects of Zr doping on the atomic and electronic properties of the ceria(1 1 1) surface were studied using first-principles density functional theory with the inclusion of on-site Coulomb interaction.
TL;DR: Comparisons of the parsimony and Bayesian analyses and results of variable length bootstrap analysis indicates that the mitochondrial 16S rRNA gene should contain important character variation to recover well-supported phylogeny of cyprinid taxa whose divergences occurred within the recent 8 MY, but could not provide resolution power for deep phylogenies spanning 10-19 MYA.
TL;DR: In this paper, a novel glycal-based O-glycosylation reaction, in which the substrates are not only peracetyl glycals but also perbenzyl glucals to afford the corresponding 2,3-unsaturated-O-glucosides via Ferrier rearrangement, was developed.
TL;DR: The proposed method, diphenylcarbazone-functionalized silica gel solid extractor, was demonstrated to be simple, fast, selective, low cost and less pollution.
TL;DR: Results suggest that [C8mim]Br exerts a toxic effect on the development of D. magna and highlights the importance of systematically evaluating the potential effects of aquatic ecosystems of ionic liquids that may be released into bodies of water.
Abstract: The developmental toxicity of 1-methyl-3-octylimidazolium bromide ([C(8)mim]Br) on Daphnia magna was investigated. The 24 and 48 h LC(50) values for [C(8)mim]Br in D. magna were 1.99 and 0.95 mg/L, respectively. A series of multigenerational toxicity tests were then used to explore [C(8)mim]Br effects in D. magna. [C(8)mim]Br significantly inhibited the body lengths of the F0 and F1 1st generations. After 21 days of exposure, [C(8)mim]Br lowered the reproductive ability of the F0 and F1 1st generations. In F1 3rd generation, 21 days of [C(8)mim]Br exposure prolonged the time to bear the first egg and the time to the first brood compared with the control, but the number of first-brood offspring and the number of broods produced by these animals were reduced. After the recovery period all the reproductive parameters returned to normal in F1 1st generation except for the number of broods. The dead neonates increased with prolonged exposure and increasing concentrations, and the dead neonates of the F1 3rd generation went far beyond that of the F1 1st and F0 generations. The intrinsic rate of natural increase (r) values of the three D. magna generations significantly decreased after exposure to higher concentrations of [C(8)mim]Br compared with control groups. Collectively, these results suggest that [C(8)mim]Br exerts a toxic effect on the development of D. magna. This study also highlights the importance of systematically evaluating the potential effects of aquatic ecosystems of ionic liquids that may be released into bodies of water.
TL;DR: Novel C6-phosphonated purine nucleosides were obtained in good to excellent isolated yields by the simple and catalyst-free SNAr-Arbuzov reaction of trialkyl phosphite with 6-choloropurine nucleotides, including a series of nonsugar carbon nucleoside.
Abstract: Novel C6-phosphonated purine nucleosides were obtained in good to excellent isolated yields by the simple and catalyst-free SNAr-Arbuzov reaction of trialkyl phosphite with 6-choloropurine nucleosides, including a series of nonsugar carbon nucleosides. Shorter reaction times were needed, and substantially higher yields were obtained under microwave irradiation conditions compared with conventional heating conditions.
TL;DR: In this paper, the authors examined the branching ratios of the rare dileptonic decays with a light CP-odd Higgs boson operator and showed that the branching ratio of these rare decays can be further enhanced with a superlight CPodd boson.
Abstract: In the next-to-minimal supersymmetric model (NMSSM) a light CP-odd Higgs boson is so far allowed by current experiments, which, together with a large tan beta, may greatly enhance the rare dileptonic decays B -> X(s)l(+)l(-) and B(s)-> l(+)l(-)gamma. We examine these decays paying special attention to the new operator allowed by the light CP-odd Higgs boson. We find that in the parameter space allowed by current experiments like CERN LEP II and b -> s gamma, the branching ratios of these rare decays can be greatly enhanced, and thus the existing experimental data on B -> X(s)mu(+)mu(-) can further stringently constrain the parameter space (especially the region with a superlight CP-odd Higgs boson and large tan beta). In the surviving parameter space we give the predictions for other dileptonic decay branching ratios and also show the results for the forward-backward asymmetry.
TL;DR: In this paper, a new method was developed for the analysis of 1-naphthylamine, N,N-dimethylaniline and diphenylamine in water samples by improved single-drop microextraction with 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM]PF6).
Abstract: A new method was developed for the analysis of 1-naphthylamine, N,N-dimethylaniline and diphenylamine in water samples by improved single-drop microextraction with 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM]PF6). Factors such as salt concentration, sample temperature, stirring rate, extraction time, pH and organic drop volume were systematically investigated. Under the optimized conditions, an excellent linear relationship was achieved in the range of 1.0–100 µg L−1 for 1-naphthylamine, diphenylamine, and 0.5-100 µg L−1 for N,N-dimethylaniline, respectively. The detection limits varied between 0.09–0.38 µg L−1, and enrichment factors ranged from 13.7 to 116.3. The precision of the method was below 8.1% (RSD). It was successfully applied to the determination of these aromatic amines in water samples. The results demonstrated that this procedure represents an efficient and sensitive method for the analysis of aromatic amines in water samples.
TL;DR: In this article, the effects of noble metal dopants on the structural and electronic properties of ceria were studied using a density functional theory (DFT) method, with the inclusion of on-site Coulomb interaction.
Abstract: The effects of noble metal (NM) dopants (NM = Pt, Rh) on the structural and electronic properties of ceria are studied using a density functional theory (DFT) method, with the inclusion of on-site Coulomb interaction (DFT + U). It is found that these NM dopants give rise to large perturbations of the atomic and electronic structures of ceria and induce metal-induced gap states at the Fermi level suitable for accommodating extra electrons, thereby lowering the reduction energy of ceria and making the NM-doped cerias more reducible than pure ceria. This mechanism for facilitating the reduction of ceria is different from that of Zr-doped ceria where the increased reducibility is largely due to the structural distortions and not to electronic modifications.
TL;DR: The strongly convergent theorems of the following implicit and explicit viscosity iterative schemes { x n } are proved in this paper, where x n is the unique solution to some co-variational inequality.
TL;DR: In this paper, the results of studies on the aggregation of 1-alkyl-3-methylimidazolium-based ionic liquids (ILs, [Cnmim]Br, n = 8, 10, 12, and 16) in aqueous solutions were reported.
TL;DR: The developed method had improved reproducibility of separation and stability of electroosmotic flow (EOF), enhanced hydrophilicity of surface and peak resolution, and decreased adsorption of biomolecules.
TL;DR: The cometabolic roles of glucose and hydrogen peroxide were investigated in decolorization of an azo dye, Reactive Black 5, by yeast isolates, Debaryomyces polymorphus and Candida tropicalis, and indicated that the dye degradation by the two yeasts was highly associated with the yeast growth process and glucose presence in the medium.
Abstract: The cometabolic roles of glucose were investigated in decolorization of an azo dye, Reactive Black 5, by yeast isolates, Debaryomyces polymorphus and Candida tropicalis. The results indicated that the dye degradation by the two yeasts was highly associated with the yeast growth process and glucose presence in the medium. Color removal of 200 mg dye/L was increased from 76.4% to 92.7% within 60 h to 100% within 18-24 h with the increase of glucose from 5 to 10 g/L, although the activity of manganese dependent peroxidase (MnP) decreased by 2-8 times in this case. Hydrogen peroxide of 233.3 mu g/L was detected in 6 h in D. polymorphus culture. The cometabolic functions of glucose and hydrogen peroxide could be also confirmed by the further color removals of 95.8% or 78.9% in the second cycle of decolorization tests in which 7 g glucose/L or 250 mu g H2O2/L was superadded respectively together with 200 mg dye/L.