Liquid-membrane electrode sensitive to ammonia and aliphatic amines based on 1-[(2-oxyphenyl)iminomethly]-2-oxybenzene-O,O',N-ammin-nickel(II) complex

In this study, an ammonia-gas-sensing liquid-state membrane electrode based on 1-[(2-oxyphenyl)iminomethyl]-2-oxybenzene-O,O',N-ammin-nickel(II) (Ni(II)-Schiff base) as an ionophore was developed. This membrane electrode gave a very good performance and exhibited linear response with near-Nernstian slope of 50.7+/-0.5 mV per decade, within a concentration range of 1.0x10(-1)-1.0x10(-3) M. The electrode performance depends on the pH of the test solution and the optimum pH range was 10.0-11.5. The effect of concentration of internal solutions in the electrode was also investigated. The selectivity properties of the electrode towards aliphatic amines at a pH value of 10.2 were investigated with the mixed-solution method. Furthermore, the response time and lifetime of the electrode prepared were determined.     

The Synthesis and Characterization of a Novel vic-Dioxime and its Mononuclear Complexes Bearing an 18-Membered 2 O 2 S 2 Macro-Cycle and Their Characteristics as Extractants for Transition Metal Ions

A new (E, E)-dioxime (H ₂ L) containing a diazadioxadithia macrocyclic moieties has been synthesized by reaction of an aromatic primary amine with cyanogendi-N-dioxide. The BF₂ ⁺-capped Ni²⁺ mononuclear complex of this new oxime has been synthesized using a precursor hydrogen-bridged mononuclear Ni²⁺ complex. The solvent extraction of transition metal cations by (3) and (6) with picrate anion into chloroform has been studied at 25 °C and UV-visible spectroscopy. The extractability and selectivity of transition metal picrates, (Pb²⁺, Ni²⁺, Co²⁺, Cd²⁺, Zn²⁺, Cu²⁺, Ag⁺) has been evaluated. The structures of new compounds are identified by using elemental analysis, ¹H and ¹³C-NMR, IR and MS spectral data.     

Determination of arsenic,cadmium and zinc in river water by neutron activation analysis

A concentration apparatus has been developed for the determination of As, Cd and Zn in water by neutron activation. The preconcentration technique used for this purpose is based on the retention of As, Cd and Zn on the Rexyn 201 resin at pH 10. The apparatus used minimizes the manipulations needed for preconcentration and contamination by trace elements present in reagents. Eleven samples of water from rivers in the Montreal region were analyzed and the following concentrations were found (in μg/1): As 0.86–1.95, Cd 0.61–0.98 and Zn 4.6–12.9.     

Identification of barley and rye varieties using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry with neural networks

Cereal varieties are normally identified using time-consuming methods such as visual examination of either the intact grain or one-dimensional electrophoretic patterns of the grain storage proteins. A fast method for identification of wheat (Triticum aestivum L.) varieties has previously been developed, which combines analysis of alcohol-soluble wheat proteins (gliadins) using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry with neural networks. Here we have applied the same method for the identification of both barley (Hordeum vulgare L.) and rye (Secale cereale L.) varieties. For barley, 95% of the mass spectra were correctly classified. This is an encouraging result, since in earlier experiments only a grouping into subsets of varieties was possible. However, the method was not useful in the classification of rye, due to the strong similarity between mass spectra of different varieties.     

Synthesis of R-(-)-2-ethyl-N-benzyl (benzo-monoaza-15-crown-5) and the Crystal Structure of Its Sodium Perchlorate Complex

A new complex of a chiral monoaza-crown ether, [R-(-)-2-ethyl-N-benzyl-4,7,10,13-tetraoxa-8,9-benzo-1-azacyclopentadec-8-ene...NaClO₄], has been prepared and studied by x-ray diffraction. The compound crystallizes in space group P2₁ with cell dimensions a = 8.721(1), b = 16.318(2), c = 8.905(1) Å, = 100.80(1)°. The sodium cation is heptacoordinated and located significantly out of the best plane of the macrocycle ring. The donor atoms of the macrocycle are in the half-chair arrangement.     

Iridoid and phenylethanoid glycosides from Phlomis longifolia var. longifolia

From the aerial parts of Phlomis longifolia var. longifolia four iridoid glucosides, shanzhiside methyl ester (1), 5-deoxypulchelloside I (2), lamalbide (3), phlomiol (4) and three phenylethanoid glycosides, verbascoside (5), forsythoside B (6), leucosceptoside A (7) along with the caffeic acid ester, chlorogenic acid (8) were isolated. The structures of the isolated compounds were established by spectroscopic (UV, IR, 1D- and 2D-NMR, FABMS) and chemical evidence. The structure elucidation of the iridoid compounds 2 and 3 are discussed in detail.     

Construction of a new Hg(2+)-selective liquid-state electrode

The construction and basic characteristics of a new liquid-state Hg(2+)-selective membrane electrode are discussed. The membrane consists of the PAN chelate of Hg(II), dissolved in CHCl(3). The linear response range of the electrode is 10(-1) -10(-5)M Hg(2+) with a slope of 28.5 mV/decade of concentration. The response time of the electrode in dilute solutions is less than 3 min, and in concentrated solutions it is only a few sec. The electrode has been used in precipitation or complexation titrations in which Hg(2+) is involved (e.g., in the determination of some organic compounds in drug synthesis).     

Iterative computation of noncooperative equilibria in nonzero-sum differential games with weakly coupled players

We study the Nash equilibria of a class of two-person nonlinear, deterministic differential games where the players are weakly coupled through the state equation and their objective functionals. The weak coupling is characterized in terms of a small perturbation parameter . With =0, the problem decomposes into two independent standard optimal control problems, while for 0, even though it is possible to derive the necessary and sufficient conditions to be satisfied by a Nash equilibrium solution, it is not always possible to construct such a solution. In this paper, we develop an iterative scheme to obtain an approximate Nash solution when lies in a small interval around zero. Further, after requiring strong time consistency and/or robustness of the Nash equilibrium solution when at least one of the players uses dynamic information, we address the issues of existence and uniqueness of these solutions for the cases when both players use the same information, either closed loop or open loop, and when one player uses open-loop information and the other player uses closed-loop information. We also show that, even though the original problem is nonlinear, the higher (than zero) order terms in the Nash equilibria can be obtained as solutions to LQ optimal control problems or static quadratic optimization problems.This research was supported in part by the US Department of Energy under Grant DE-FG-02-88-ER-13939.Paper presented at the 29th IEEE Conference on Decision and Control, Honolulu, Hawaii, 1990.     

The Scaled Hermite–Weber Basis Still Highly Competitive

The effectiveness of the usual harmonic oscillator basis is demonstrated on a wide class of Schrödinger Hamiltonians with various spectral properties. More specifically, it is shown numerically that an appropriately scaled Hermite–Weber basis yields extremely accurate results not only for the energy eigenvalues which differ slighly from the harmonic oscillator levels, but also for the states which reflect a purely anharmonic character.     

Aromatic polyamides with pendent acetoxybenzamide groups and thin films made therefrom

New aromatic polyamides containing 1,3,4-oxadiazole or benzonitrile units in the main chain and 5-(4-acetoxybenzamido) groups in the side chain have been synthesized and their properties have been characterized and compared with those of related polyamides and polyoxadiazole-amides. These polymers show good thermal stability, with initial decomposition temperature being at about 300 °C and glass transition temperature in the range of 260-280 °C. They are easily soluble in certain solvents such as N-methylpyrrolidinone (NMP), N,N^′-dimethylacetamide (DMA) and N,N^′-dimethylformamide (DMF) and can be cast from solutions into thin flexible films. The polymer films had tensile strengths in the range of 77-97 MPa, tensile moduli in the range of 2.3-2.6 GPa and elongation at break values ranging from 6% to 24%. One of the polymers containing the 1,3,4-oxadiazole ring exhibited blue fluorescence.