The Three-component One-pot Synthesis of 4,6-Diarylpyrimidin-2(1h)-ones and 9-Phenyl-8-oxa-10,12-diaza-tricyclo[7.3.1.0~(2,7)]trideca-2(7),3,5-trien-11-one

1 Results Pyrimidinones (PMs) are a class of important heterocycles which have been well documented throughout the literature due to their biological importance. They exhibit a wide range of pharmaceutical and therapeutic properties[1].A rapid and efficient one-pot method for the synthesis of 4,6-diarylpyrimidin-2(1H)- ones and related heterocycles is described.The condensation of acetophenone derivatives,aldehydes and urea in the presence of sulfamic acid was employed to synthesize a variety of pyrimid...     

Modeling European industrial production with multivariate singular spectrum analysis: A cross‐industry analysis

In this paper, an optimized multivariate singular spectrum analysis (MSSA) approach is proposed to find leading indicators of cross‐industry relations between 24 monthly, seasonally unadjusted industrial production (IP) series for German, French, and UK economies. Both recurrent and vector forecasting algorithms of horizontal MSSA (HMSSA) are considered. The results from the proposed multivariate approach are compared with those obtained via the optimized univariate singular spectrum analysis (SSA) forecasting algorithm to determine the statistical significance of each outcome. The data are rigorously tested for normality, seasonal unit root hypothesis, and structural breaks. The results are presented such that users can not only identify the most appropriate model based on the aim of the analysis, but also easily identify the leading indicators for each IP variable in each country. Our findings show that, for all three countries, forecasts from the proposed MSSA algorithm outperform the optimized SSA algorithm in over 70% of cases. Accordingly, this new approach succeeds in identifying leading indicators and is a viable option for selecting the SSA choices L and r, which minimizes a loss function.     

Characterization of mechanothermally processed nanostructured ZnO

In this paper, the Taguchi method with an L₉(34) orthogonal array was used as experimental design to determine the optimum conditions for preparing ZnO nanoparticles via a mechanothermal route. ZnSO₄·H₂O and Na₂CO₃ were used as starting materials. The effects of milling time, Na₂CO₃/ZnSO₄·H₂O molar ratio, and ball-to-powder mass ratio (BPR) on the bandgap (E_g) of ZnO nanoparticles were investigated. The ranges of the investigated experimental conditions were 5–15 h for the milling time (t), 1.0–1.2 for the Na₂CO₃/ZnSO₄·H₂O molar ratio (M), and 10–30 for BPR. The milling time and BPR exhibited significant effects; an increase in milling time reduced the bandgap. The optimum conditions from this study were t₃ = 15 h, M₁ = 1, and BPR₂ = 20. Only two significant factors (t₃, 15 h; BPR₂, 20) were used to estimate the performance at the optimum conditions. The calculated bandgap was 3.12 eV, in reasonable agreement with the experimental results obtained under the optimized conditions.     

Are household subjective forecasts of personal finances accurate and useful? A directional analysis of the British Household Panel Survey

The purpose of the paper is to analyse the accuracy and usefulness of household subjective forecasts of personal finance. We use non‐parametric directional analysis to assess the subjective forecasts which are based on qualitative judgments. Using the British Household Panel Survey (BHPS) we are able to analyse a large number of individuals over a number of years. We also take into account individual characteristics such as gender, age, education and employment status when assessing their subjective forecasts. The paper extends the existing literature in two ways: the accuracy and usefulness of subjective forecasts, based on directional analysis, are assessed at the household level for the first time. Secondly, we adapt and extend the methods of directional analysis, which are applied to the household panel or longitudinal survey. Copyright © 2008 John Wiley & Sons, Ltd.     

Liquid-phase aerobic oxidation of benzyl alcohol catalyzed by mechanochemically synthesized manganese oxide

Benzyl alcohol oxidation by molecular oxygen using solid manganese oxide as a catalyst and n-heptane as the solvent was studied in the liquid phase. The catalyst was synthesized by a simple mechanochemical process at room temperature and was characterized by different physical methods. The catalyst was highly active and 100% selective for benzyl alcohol conversion to benzaldehyde. The solid catalyst can be recovered from the reaction mixture by simple filtration and can be re-used. We found n-heptane to be an excellent solvent for the oxidation reaction, and that the catalyst did not leach into solution.     

(Ⅲ)m=0类二次系统的极限环问题,(Ⅰ)

从本文开始我们对(Ⅲ)m=0类二次系统的极限环问题作了一系统研究,按照其系数的各种不同情况分类讨论．本文考察l<1/2,01的情况,给出了极限环惟一性的一些结论,并指出有时在一个焦点外围可以存在两个极限环,同时分析了系统的拓扑结构的变化．     

Evaluation of charge storage ability of chrome doped Mn2O3 nanostructures derived by cathodic electrodeposition

A facile synthetic route has been proposed to prepare cauliflower-like nanostructures of Cr doped Mn2O3. The synthesis was carried out by constant current cathodic electrodeposition from Mn2+ nitrate solutions containing minor amounts of dichromate. It was found that the presence of Cr mediates the formation of cathodic MnO2 which then reacts with the excess Mn2+ species to form Mn2O3 nanostructures. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Differential Thermal Analysis (DTA) were used to characterize the nanostructures. The storage ability of the obtained nanostructures was investigated by cyclic voltammetry (CV) in 0.5 M Na2SO4 solution. The results indicated that the Cr doped manganese oxide material shows better performance than the non-doped one, and the charge capacity (SC) of doped manganese oxide (218 F/g) was higher than pure manganese oxide (208 F/g).     

Photocatalytic degradation of methylene blue by nanostructured Fe/FeS powder under visible light

The photocatalytic performance of mechano-thermally synthesized Fe/FeS nanostructures formed from micron-sized starting materials was compared with that of a thermally synthesized nanostructure with nano-sized precursors in this paper. The properties of as-synthesized materials were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), diffuse reflectance spectroscopy (DRS), and ultraviolet-visible (UV-Vis) spectroscopy. The effects of irradiation time, methylene blue (MB) concentration, catalyst dosage, and pH value upon the degradation of MB were studied. Magnetic properties of the samples showed that both as-synthesized Fe/FeS photocatalysts are magnetically recoverable, eliminating the need for conventional filtration steps. Degradation of 5 ppm of the MB solution by mechano-thermally synthesized Fe/FeS with a photocatalyst dosage of 1 kg/m3 at pH 11 can reach 96% after 12 ks irradiation under visible light. The photocatalytic efficiency is higher in alkaline solution. The kinetics of photocatalytic degradation in both samples is controlled by a first-order reaction. However, the rate-constant value in the thermally synthesized Fe/FeS photocatalyst sample is only 1.5 times greater than that of the mechano-thermally synthesized one.