Adsorption of heavy metal ions by immobilized phytic acid

Applied Biochemistry and Biotechnology - Phytic acid (myoinositol hexaphosphate) or its calcium salt, phytate, is an important plant constituent. It accounts for up to 85% of total phosphorus in...     

Spectral,luminescent, and lasing properties of pyran derivatives in thin acrylic films under optical excitation

Absorption and fluorescence spectra and lasing ability of pyran derivatives in thin polymeric layers (0.5–0.8 μm) based on polymethylmethacrylate and copolymerized methylmethacrylate and methacrylic acid are investigated. It is revealed that the absorption and luminescence intensities and the laser service lifetime of dicyanomethilene (DCM) pyran derivatives are determined by their composition and nature of the polymeric medium. Compositions based on DCM and examined polymers are of interest for preparation of thin-film active media lasing in the red range of the spectrum. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 63–66, October, 2005.     

Function spaces between BMO and critical Sobolev spaces

The function spaces Dk(Rn) are introduced and studied. The definition of these spaces is based on a regularity property for the critical Sobolev spaces Ws,p(Rn), where sp=n, obtained by J. Bourgain, H. Brezis, New estimates for the Laplacian, the div-curl, and related Hodge systems, C. R. Math. Acad. Sci. Paris 338 (7) (2004) 539-543 (see also J. Van Schaftingen, Estimates for L¹-vector fields, C. R. Math. Acad. Sci. Paris 339 (3) (2004) 181-186). The spaces Dk(Rn) contain all the critical Sobolev spaces. They are embedded in BMO(Rn), but not in VMO(Rn). Moreover, they have some extension and trace properties that BMO(Rn) does not have.     

“Surprising kinetics” or the major role of trace quantities in radical chain mechanisms

Although hydrogen abstraction from 1,1,1,2-tetrachloroethane should produce only one kind of radical, CCl₃CHCl, the presence of small amounts of trichloroethene, as impurity as well as product of reaction, induces the formation of the a priori unexpected CHCl₂CCl₂ radicals. The importance of this radical in the reaction pathways of the chlorination and the chlorine induced dehydrochlorination of CCl₃CH₂Cl, under different experimental conditions, is computed and discussed. For example, at 380 K, and for small partial pressures of chlorine (2 torr), the CHCl₂CCl₂ radicals account for more than 70% of the formation of the reaction products after only 2% reaction. The major role of trace quantities in long chain radical reactions is emphasized. © 1993 John Wiley & Sons, Inc.     

The Millimeter-Wave Spectrum of 2,3-Dihydrofuran

The millimeter-wave spectrum of 2,3-dihydrofuran in the ground and five ring-puckering excited states has been measured in the frequency range 100–250 GHz. The ground and first ring-puckering excited states have been fitted to a two-state Hamiltonian including Coriolis coupling interaction. The determined energy difference of 18.684(7) cm⁻¹between these states and theaandbtype coupling parameters are consistent with the ring-puckering potential function and the previously observed dependence of the centrifugal distortion constants Δ_JK, Δ_K, and δ_K. A small ring-puckering dependence of the quartic centrifugal distortion constants Δ_Jand δ_Jhas been also observed. This dependence is well accounted for in terms of the ring-puckering potential function and the vibrational dependence of the rotational constants.