Copolycarbonates of isosorbide and various diols

Isosorbide and equimolar amounts of various diols were polycondensed with diphosgene and pyridine. Bisphenol A, 3,3′‐dimethyl bisphenol A, bisphenol C, 1,3‐bis(4‐hydroxybenzoyloxy)propane, and 1,4‐cyclohexane diol were used as comonomers. The compositions were determined by ¹H NMR spectroscopy; the random sequences were characterized by ¹³C NMR spectroscopy. For the high‐molar‐mass copolycarbonates of bisphenol A, 3,3′‐dimethyl bisphenol A, and bisphenol C, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry proved that the chain growth was mainly limited by cyclization. Copolycarbonates with alternating sequences were obtained by the polycondensation of bisphenol A with isosorbide bischloroformiate or from isosorbide and bisphenol A bischloroformiate. In these cases, large amounts of cyclic oligo‐ and polycarbonates were also formed. The glass‐transition temperatures were determined by differential scanning calorimetry measurements. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3616–3628, 2006     

A semantical proof of the strong normalization theorem for full propositional classical natural deduction

We give in this paper a short semantical proof of the strong normalization for full propositional classical natural deduction. This proof is an adaptation of reducibility candidates introduced by J.-Y. Girard and simplified to the classical case by M. Parigot.     

Capillary electrophoretic analysis of sulfur and cyanicides speciation during cyanidation of gold complex sulfidic ores

A capillary electrophoretic protocol for the separation and quantification of the most important species potentially liberated during the cyanidation of gold sulfide‐rich ores was accomplished in this study. The separation of 11 ions: S₂O₃^2–, Cu(CN)₃^2–, Fe(CN)₆^4–, Fe(CN)₆^3–, SCN^–, Au(CN)₂^–, Ag(CN)₂^–, SO₄^2–, OCN^–, SO₃^2–, and HS^– was achieved using an indirect UV detection method. The robustness of the analytical protocol was tested by analyzing ions speciation during the cyanidation of two gold sulfide‐rich ores. The 1‐h cyanidation of the two ores released up to six complexes into solution: S₂O₃^2–, Cu(CN)₃^2–, SCN^–, Fe(CN)₆^4–, OCN^–, and SO₄^2–. The mineralogy of the ore was found to influence directly the nature and the amount of the dissolved species. Conserving the cyanidation solution for 72 h after sampling resulted in 96% total sulfur recovery. These results allow us to conclude that the analytical protocol developed in this study can become very useful for the optimization of precious‐metals cyanidation plants.     

Waste-free thiolysis of epoxide in water with high yield

An environmentally benign and efficient process for the preparation of β-hydroxysulfides was developed by a practical and simple reaction of thiols with epoxides in water catalyzed by K₂CO₃ in high yields and short reaction times.     

The impact of lead pollution on the environment of Rabat-Sale' (Morocco)

There are numerous possible vectors of industrial lead poisoning in unprotected work environments and the areas surrounding industrial sites. In the Rabat-Salé region, ceramics is the industry which uses most lead. Galena (PbS) is used in the fabrication of some types of pottery, and other lead-based compounds are used as glaze. A second source of lead pollution is the production of some fuels, in which lead is used as an anti detonator. In order to evaluate the impact of lead contamination on the environment, our investigation is focused on the lead concentration in the atmosphere, soil and vegetation at five stations in the Rabat-Salé region. We found concentrations of lead higher than those published for any other country in the atmosphere and vegetation near the ceramics factories of Rabat-Salé. These concentrations decreased significantly as we moved away from urban areas.     

Computerized data acquisition and processing for Shpol'skii high-resolution spectrofluorimetry

The program described provides simultaneously digital control of a high-resolution spectrofluorimeter, acquisition of analog signals and data storage, and contains graphics processing to visualize spectra. Automatic evaluation software, which evaluates peak heights and calculates concentrations is included. The program runs on an IBM PC-AT2 (or compatible) equipped with interface cards; it is composed of distinct modules which are obtained through a menu. The system has been applied to the determination of 13 polynuclear aromatic hydrocarbons (PAHs); it offers high selectivity, excellent detection limits, and rapidity of data acquisition. Results obtained for 9 PAHs in a standard urban dust (SRM-1649) were satisfactory.     

Approximate solutions of Dirac equation for Tietz and general Manning-Rosen potentials using SUSYQM

In this paper, we consider the relativistic Dirac equation with Tietz and general Manning-Rosen potential. By using appropriate approximation, we obtained the approximate analytical solutions of the Dirac equation for the combined potential via the supersymmetric quantum mechanics (SUSYQM). Within the framework of spin and pseudospin symmetry limits, we obtained the relativistic energy eigenvalus and the corresponding components of the wave functions for Tietz and Manning-Rosen potential using the SUSYQM. We have also reported some numerical results and figures to show the effect of the tensor interactions.     

Structure of \mathrm {Gal}(\mathbb {k}_2^{(2)}/\mathbb {k}) for some fields \mathbb {k}=\mathbb {Q}(\sqrt{2p_1p_2},i) with \mathbf {C}l_2(\mathbb {k})\simeq (2, 2, 2)

Let \(p_1 \equiv p_2 \equiv 5\pmod 8\) be different primes. Put \(i=\sqrt{-1}\) and \(d=2p_1p_2\) , then the bicyclic biquadratic field \(\mathbb {k}=\mathbb {Q}(\sqrt{d},i)\) has an elementary abelian 2-class group of rank \(3\) . In this paper we determine the nilpotency class, the coclass, the generators and the structure of the non-abelian Galois group \(\mathrm {Gal}(\mathbb {k}_2^{(2)}/\mathbb {k})\) of the second Hilbert 2-class field \(\mathbb {k}_2^{(2)}\) of \(\mathbb {k}\) . We study the capitulation problem of the 2-classes of \(\mathbb {k}\) in its seven unramified quadratic extensions \(\mathbb {K}_i\) and in its seven unramified bicyclic biquadratic extensions \(\mathbb {L}_i\) .     

Versatile and Large-Scale Synthesis of Functional Dithiocarbamates in Water

Structural diversity is possible in direct access to functional dithiocarbamates based on a highly efficient and simple one-pot reaction of CS₂, amines, and alkyl halides in nearly quantitative yields in water.