Optimization of the synthesis and characterizations of chemical bath deposited Cu2S thin films

Semiconducting copper sulphide (Cu₂S) thin films have been deposited on various substrates (SnO₂:F/glass, glass) by the simple and economical chemical bath deposition technique. The depositions were carried out during a deposition time of about 32.5 min in the pH range of 9.4 to 11. The synthesized Cu₂S thin films were characterized using various techniques without any annealing treatment. X-ray diffraction study shows that Cu₂S films exhibit the best crystallinity for pH = 10.2. For this pH value, Auger electron spectroscopy investigations show that Cu₂S thin films grown on an SnO₂/glass substrate exhibit stochiometric composition with [Cu]/[S] concentrations ratio equal to 2.02. Using the Kelvin method, the work function difference (Ф_material– Ф_probe) for the Cu₂S films deposited on SnO₂/glass substrates at the optimum pH value was found to be equal to 145 meV. Hall measurements confirm the p-type electrical conductivity of the obtained films. The electrical resistivity was of the order of 3.85 × 10⁻⁴ Ω-cm. The transmission and reflection coefficients vary in the range of [35–60] % and [5–15] % respectively, in the visible range, and the band gap energy is about 2.37 eV.     

一种新的双正交小波的构造方法研究

在二进提升方案相关理论的基础上,结合双正交性、消失矩性和对称性条件,提出一种构造提升双正交小波的新方法.此方法从二进小波出发,考虑小波所具有的特性,通过选取适当的提升参数,具体构造了具有紧支撑、对称性、高阶消失矩和速降性的提升双正交小波.     

Stereoselective Synthesis of Functionalized 1,4-Dienes

The article reports a stereoselective synthesis of functionalized 1,4-dienes 5, 6 by coupling allylic Baylis–Hillman acetates 1 and vinyl magnesium chloride at low temperature and in the presence of a catalytic amount of LiCuBr₂ (3%).     

Existence of positive bounded solutions for some nonlinear elliptic systems

We prove some existence results of positive bounded continuous solutions to the semilinear elliptic system Δu=λp(x)g(v), Δv=μq(x)f(u) in domains D with compact boundary subject to some Dirichlet conditions, where λ and μ are nonnegative parameters. The functions f,g are nonnegative continuous monotone on (0,∞) and the potentials p, q are nonnegative and satisfy some hypotheses related to the Kato class K(D).     

An efficient synthesis of alkyl α-(hydroxymethyl)acrylates induced by DABCO in an aqueous medium

Alkyl α-(hydroxymethyl)acrylates are prepared in high yields on a synthetic scale by hydroxymethylation of the corresponding acrylates using 30% aqueous formaldehyde in THF or DME as solvent and DABCO as the catalyst.     

Polyvinyl alcohol-acid redox active gel electrolytes for electrical double-layer capacitor devices

Journal of Solid State Electrochemistry - Since the mechanism of charge storage in electrical double-layer capacitors (EDLCs) relies on diffusion of ions into the pores of the electrodes, in...     

The removal of methylene blue as a remedy of dye-based marine pollution: a photocatalytic perspective

Research on Chemical Intermediates - The effluents containing the discarded water from the textile industry are graded as one of the foremost pollutants in all industrial sectors. The wide...     

Fatigue behaviour and structural health monitoring by acoustic emission of E-glass/epoxy laminates with piezoelectric implant

This paper represents the continuation of our research on built-in piezoelectric sensor for structural health monitoring of composite materials. Experimental research is focused on examining the effects of the embedded sensors on the structural integrity of composite laminates subjected to mechanical tests. A series of composite specimens with and without embedded sensor are tested in fatigue loading while constantly monitoring the response by acoustic emission technique. The acoustic signals are analysed using the classification k-means method in order to identify the different damage mechanisms and to follow the evolution of these mechanisms for both types of composite materials (with and without sensor). The mechanical behaviour of composites with and without embedded sensor shows no difference in the form. The incorporation of piezoelectric sensor causes low degradation of mechanical properties of composites. Comparing embedded sensor to sensor mounted on the surface, the embedded sensor showed a much higher sensitivity. It is thus verified that the embedded acoustic emission sensor had great potential for acoustic emission monitoring in fibre reinforced composite structures.     

Ultra high performance liquid chromatography with mass spectrometry method for the simultaneous determination of phenolic constituents in honey from various floral sources using multiwalled carbon nanotubes as extraction sorbents

An ultra high performance liquid chromatography with mass spectrometry method has been developed for the simultaneous separation, identification and determination of 22 phenolic constituents in honey from various floral sources from Yemen. Solid‐phase extraction was used for extraction of the target phenolic constituents from honey samples, while multiwalled carbon nanotubes were used as solid‐phase adsorbent. The chromatographic separation of all phenolic constituents was performed on a BEH C₁₈ column using a linear gradient elution with a binary mobile phase mixture of aqueous 0.1% formic acid and methanol. The quantitation was carried out in selected ion reaction monitoring acquisition mode. The total amount of phenolic acids, flavonoids and other phenols in each analyzed honey was found in the range of 338–3312, 122–5482 and 2.4–1342 μg/100 g of honey, respectively. 4‐Hydroxybenzoic acid was found to be the major phenolic acid. The main detected flavonoid was chrysin, while cinnamic acid was found to be the major other phenol compound. The regeneration of solid phase adsorbent to be reused and recovery results confirm that the proposed method could be potentially used for the routine analysis of phenolic constituents in honey extract.