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991.
Six new complexes of thallium(III) of the formula (π-D)2Tl(L) (where D= cyclopentadienyl or indenyl group and L=nitro, nitrito or nitrato group) have been prepared and characterised on the basis of I. R. studies and some thermal properties of these complexes. 相似文献
992.
The steady flow in a parallel plate channel rotating with an angular velocity Ω and bounded below by a permeable bed is analysed
under the effect of buoyancy force. On the porous bed the boundary condition of Beavers and Joseph is applied and an exact
solution of the governing equations is found. The solution in dimensionless form contains four parameters: The permeability
parameterσ
2, the Grashof numberG, the rotation parameterK
2 and a dimensionless constantα. The effects of these parameters, specially,σ
2, G andK
2, on the slip velocities and velocity distributions are studied. For largeK
2, there arise thin boundary layers on the walls of the channel. 相似文献
993.
Microwave (MW) assisted synthesis of acridine and quinazoline derivatives was performed on thin layer chromatography (TLC) plates. This versatile, simple and economical green methodology is readily amenable to parallel synthesis of acridine and quinazoline compound libraries. 相似文献
994.
A nearly symmetric alkoxyphenylbenzoate monomer is found to exhibit a transition from perpendicular to tilted alignment at a lecithin-treated glass substrate several degrees below the nematic-isotropic phase transition. By means of the Freedericksz transition the coefficient B of the anchoring energy has been obtained. It is found that B rapidly decreases, and the tilt susceptibility increases on approaching this transition. 相似文献
995.
Marimuthu Govindarajan Mohan Rajeswary S. L. Hoti Marcello Nicoletti 《Natural product research》2016,30(21):2491-2494
Plant-borne compounds have been proposed for extracellular synthesis of mosquitocidal nanoparticles. However, their impact against mosquito natural enemies has been scarcely studied. Here, we synthesised silver nanoparticles (Ag NPs) using Mussaenda glabra leaf extract as reducing and stabilising agent. Biofabricated Ag NPs were characterised by UV–vis spectrophotometry, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Compared to the leaf aqueous extract, biosynthesised Ag NPs showed higher toxicity against mosquito vectors Anopheles subpictus, Aedes albopictus and Culex tritaeniorhynchus with LC50 of 17–19 μg/mL, respectively. Ag NPs were found safer to non-target organisms Diplonychus indicus and Gambusia affinis, with respective LC50 values ranging from 1446 to 8628 μg/mL. Overall, M. glabra-fabricated Ag NPs are a promising and eco-friendly tool against larval populations of mosquito vectors of medical and veterinary importance, with negligible toxicity against other non-target aquatic organisms. 相似文献
996.
997.
998.
Dhanpat Rai Dean A. Moore Kevin M. Rosso Andrew R. Felmy Harvey BoltonJr. 《Journal of solution chemistry》2008,37(7):957-986
Ethylenediaminetetracetic acid (EDTA), which was co-disposed with Pu at several US Department of Energy sites, has been reported
to enhance the solubility and transport of Pu. It is generally assumed that this enhanced transport of Pu in geologic environments
is a result of complexation of Pu(IV) with EDTA. However, the fundamental basis for this assumption has never been fully explored.
Whether EDTA can mobilize Pu(IV) in geologic environments is dependent on many factors, chief among them are not only the
complexation constants of Pu with EDTA and dominant oxidation state and the nature of Pu solids, but also (1) the complexation
constants of environmentally important metal ions (e.g., Fe, Al, Ca, Mg) that compete with Pu for EDTA and (2) EDTA interactions
with the geomedia (e.g., adsorption, biodegradation) that reduce effective EDTA concentrations available for complexation.
Extensive studies over a large range of pH values (1 to 14) and EDTA concentrations (0.0001 to 0.01 mol⋅L−1) as a function of time were conducted on the solubility of 2-line ferrihydrite (Fe(OH)3(s)), PuO2(am) in the presence of different concentrations of Ca ions, and mixtures of PuO2(am) and Fe(OH)3(s). The solubility data were interpreted using Pitzer’s ion-interaction approach to determine/validate the solubility product
of Fe(OH)3(s), the complexation constants of Pu(IV)-EDTA and Fe(III)-EDTA, and to determine the effect of EDTA in solubilizing Pu(IV)
from PuO2(am) in the presence of Fe(III) compounds and aqueous Ca concentrations. Predictions based on these extensive fundamental
data show that environmental mobility of Pu as a result of Pu(IV)-EDTA complexation as reported/implied in the literature
is a myth rather than the reality. The data also show that in geologic environments where Pu(III) and Pu(V) are stable, the
EDTA complexes of these oxidation states may play an important role in Pu mobility. 相似文献
999.
The sulphur containing inhibitors (I), cysteine (Cys) and sodium thiosulphate (THS), have been found to inhibit Hg(II) catalyzed exchange of cyanide in hexacyanoferrate(II) by nitroso-R-salt (NRS). The inhibitory effect of both the ligands are attributed to their binding tendencies with Hg(II) leading to the formation of catalyst-inhibitor (C-I) complex. The reactions have been followed spectrophotometrically in aqueous medium at 720 nm by noting the increase in absorbance of the green colour product, [Fe(CN)5NRS]3− at pH 6.50 ± 0.02, temp 25.0 ± 0.1 °C and ionic strength (μ) 0.1 M (KNO3). A most plausible mechanistic scheme involving the role of analytes (inhibitors) has been proposed. The values of equilibrium constants for complex formation between catalyst-inhibitor (KCI), catalyst-substrate (KS) and Mechaelis-Menton constant (Km) have been computed from the kinetic data. The linear calibration curves have been established between absorbance and inhibitor concentrations under specified conditions. Cys and THS have been determined in the range 1-5 × 10− 7 M and 4.9-16.9 × 10− 7 M respectively. The detection limits have been computed to be 1 × 10− 7 M and 4.9 × 10− 7 M for Cys and THS, respectively. 相似文献
1000.
Microwave enhanced diversity oriented synthesis (MEDOS) of various N- and O-heterocyclic systems fused with 1,3-oxazine ring is reported. The synthesis represents a new montmorillonite K-10 clay-catalyzed green protocol, which utilizes d-glucose/d-xylose as biorenewable feedstocks. d-Glucose/d-xylose-derived 1,3-oxazin-2-ones(thiones) either directly undergo K-10 clay-catalyzed cyclization to yield pyrano-/furo-1,3-oxazine systems under solvent-free microwave irradiation conditions or afford azolo-/azino-1,3-oxazines when subjected to Malaprade reaction followed by cyclization with appropriate reagents, viz. phenylhydrazine, hydroxylamine, acetamidine, phenylurea and semi(thiosemi)carbazide. 相似文献