Synthesis of tertiary α-amino phosphonate by one-pot three-component coupling mediated by LPDE

A very mild, efficient and simple method for the synthesis of tertiary α-amino phosphonates is reported by reaction of an aldehyde, a secondary amine and trialkylphosphite in ethereal solution of lithium perchlorate, LPDE, at ambient temperature with high yields.     

Predictive accuracy determination applied to a linear model phosphorus loading resulting from urban runoff

A case study of the application of an iterative technique for determination of predictive accuracy is presented. The method uses Monte Carlo simulations and split sampling techniques to verify model accuracy. Examination of the ability of a linear parametric runoff loading model's ability to project total phosphorus loadings reveals the sensitivity of the model to calibration procedures. Predictive reliability was found to vary widely as the number of rainfall events considered in the calibration process changed. Predictive reliability was substantially increased by imposing calibration constraints which ensured that a wide distribution of values of the independent variable were presented in the calibration pool.Although the linear model is theoretically weak in its representation of the runoff loading phenomenon, it displays relatively stable predictive capabilities which warrant its consideration for use in management studies. The predictive errors associated with loading projections limit the linear model's value to applications insensitive to errors in the loading projections for individual storm events. This study provides further evidence of the need to consider uncertainties associated with the modelling of water quality phenomena.     

Electronic structure of C co-doped (Ga,Fe)N-based diluted magnetic semiconductors

We report results of the study on GaN doped with Fe and co-doped with Carbon (C), for acceptors defect, making use of the spin-polarized relativistic Korringa-Kohn-Rostoker coherent-potential approximation method. In order to understand and to explain the half-metallicity and ferromagnetism stability, observed in Ga_0.95Fe_0.05N with acceptor defects, we calculated the electronic structure and magnetic properties of p-type Ga_0.95Fe_0.05N. Furthermore, comparison between the electronic structure of the substitutional and interstitial carbon in (Ga, Fe)N is also given. Mechanism of exchange interaction between magnetic ions in Ga_0.95Fe_0.05N with acceptor defect is investigated. The hyperfine interaction has been calculated for the disordered alloy systems Ga_0.95Fe_0.05N_1-xC_x (0.01 ≤ x ≤ 0.08).     

Crystal structure and electrical properties study of 4-aminopyridinium chloridobismuthate (III) (C5N2H7)4.HBi2Cl11

The crystal structure of (C₅N₂H₇)₄.HBi₂Cl₁₁ has been determined at room temperature by single crystal X-ray diffraction. The compound crystallizes in the triclinic system with Pī space group. The crystal structure consists of two asymmetric inequivalent molecules of 4-aminopyridinium and anionic HBi₂Cl₁₁ chains. The HBi₂Cl₁₁ anionic chains stacked along the a-axis are formed with Bi₂Cl₁₁ dimers connected to each other via hydrogen atoms. The crystal packing is stabilized with N–H...Cl hydrogen bonds connecting aminopyridinium units to the HBi₂Cl₁₁ anionic chains. The title compound exhibits an order–disorder phase transition at 338 K. The AC electrical conductivity properties of (C₅N₂H₇)₄.HBi₂Cl₁₁ compound have been investigated by means of impedance spectroscopy measurements over wide ranges of frequencies and temperatures, 200 Hz to 5 MHz and 303 to 418 K, respectively. Detailed analysis of the impedance spectrum suggests that the electrical properties of the material are strongly temperature dependent. The frequency-dependent conductivity data were fitted in the Jonscher's law: $ \sigma \left( \omega \right) = \sigma (0) + A{\omega^n} $ . The nature of variation of DC conductivity suggests Arrhenius type of electrical conductivity.     

Some Generalized q-Bessel Type Wavelets and Associated Transforms

In this paper wavelet functions are introduced in the context of q-theory.We precisely extend the case of Bessel and q-Bessel wavelets to the generalized q-Bessel wavelets.Starting from the(q,v)-extension(v =(α,β)) of the q-case,associated generalized q-wavelets and generalized q-wavelet transforms are developed for the new context.Reconstruction and Placherel type formulas are proved.     

Dealing with external actions in belief causal networks

Graphical models are efficient and simple ways to represent dependencies between variables. We introduce in this paper the so-called belief causal networks where dependencies are uncertain causal links and where the uncertainty is represented by belief masses. Through these networks, we propose to represent the results of passively observing the spontaneous behavior of the system and also evaluate the effects of external actions. Interventions are very useful for representing causal relations, we propose to compute their effects using a generalization of the “do” operator. Even if the belief chain rule is different from the Bayesian chain rule, we show that the joint distributions of the altered structures to graphically describe interventions are equivalent. This paper also addresses new issues that are arisen when handling interventions: we argue that in real world applications, external manipulations may be imprecise and show that they have a natural encoding under the belief function framework.     

Diamondoid Nanostructures as sp3‐Carbon‐Based Gas Sensors

Diamondoids, sp³‐hybridized nanometer‐sized diamond‐like hydrocarbons (nanodiamonds), difunctionalized with hydroxy and primary phosphine oxide groups, enable the assembly of the first sp³‐C‐based chemical sensors by vapor deposition. Both pristine nanodiamonds and palladium nanolayered composites can be used to detect toxic NO₂ and NH₃ gases. This carbon‐based gas sensor technology allows reversible NO₂ detection down to 50 ppb and NH₃ detection at 25–100 ppm concentration with fast response and recovery processes at 100 °C. Reversible gas adsorption and detection is compatible with 50 % humidity conditions. Semiconducting p‐type sensing properties are achieved from devices based on primary phosphine–diamantanol, in which high specific area (ca. 140 m² g^?1) and channel nanoporosity derive from H‐bonding.     

Highly Sensitive Enzyme-free Sensor Based on a Carbon Paste Electrode Modified with Binary Zinc Oxide/Polyaniline Nanocomposites for Dopamine,Ascorbic Acid and Uric Acid Sensing

Hybrid composites ZnO/PANI were facily synthesized by a sonication process at room temperature. This procedure is non-expensive, time/energy saving and environmentally safe. The as-prepared ZnO/PANI were characterized by FTIR, UV-vis spectroscopies and SEM in order to investigate the structure and morphology of the studied composites. The samples were used to modify carbon paste electrode (CPE) in order to develop electrochemical biosensors (ZnO/PANI/CPE). The sensing properties of the nanoparticles were evaluated for dopamine, ascorbic acid and uric acid non-enzymatic detection. The effect of percentage of polyaniline in the composites and the effect of calcination on the biosensor's response were also examined in the present study. It was revealed that the existence of PANI in ZnO/PANI/CPE largely enhanced the electroactive surface area and therefore the sensitivity for electrochemical sensing. A good electrochemical behavior was noted for ZnO/40 wt% PANI-cal/CPE modified electrode toward DA, AA and UA oxidation. The electroactive surface area of the previously mentioned modified electrode (0.235 cm²) was two times higher than that of the bare electrode (0.117 cm²). The liner relationships between current intensities and concentrations were found to be 0.01–1.4 mM, 0.1–1.3 mM and 0.01–0.12 mM, with detection limit of 0.029 mM, 0.063 mM and 0.007 mM, for DA, AA and UA respectively. In the mixtures of ascorbic acid (AA), dopamine (DA) uric acid (UA) and glucose (Glu) the sensor showed high selectivity of DA with low interference of ascorbic acid by a current change of 14 %. The as-prepared ZnO/PANI/CPE biosensor displayed a good reproducibility and stability.