Electrodeposited CdSe0.5Te0.5: Photoelectrochemical solar cells

CdSe_0.5Te_0.5 thin films have been prepared by electrodeposition. The films were characterized by X-ray diffraction, energy dispersive X-ray fluorescence microanalysis, scanning electron microscopy, optical absorption techniques, Auger electron analysis and electron probe microanalysis. Photoelectrochemical cell performance after electrode annealing and photoetching treatments is reported.     

Efficiency of transport-dump systems when working fireclay deposits

Conclusions The article recommends the method of determining the basic parameters of the transport-dump systems for working fireclays; the maximum height of the overburden shelf needed, the required length of working front and the useful volume of mining the clays.With all-year-round working in the mines the use of the excavator ERG-35/1000 in combination with the swing chute OSh-105/1500 is desirable with a height of overburden work of up to 13 m; above 13 m it is more economical to use the excavator ERG-350/1000 in combination with the bridge OMSh-65/1200.     

Studies of microhardness and mar resistance using a scanning probe microscope

Scanning probe microscopy (SPM) is in a period of rapid development. It shows great promise for characterizing coating surfaces. This paper describes modification of an SPM so that it can be used to mar the surfaces of coatings under controlled conditions and to characterize the mars. Mar resistance of coatings is analyzed in terms of a ‘three response, two mechanism model.' The three responses (fracture, elastic, and plastic) can be measured quantitatively using the SPM. Of the three responses, only two (fracture and plastic deformation) are marring mechanisms – elastic deformations recover instantaneously. In some cases mars resulting from plastic deformation may recover slowly with time or with immersion in water; this phenomenon is attributed to viscoelastic creep. Microhardness is also measured with the modified SPM. Some thermoset coatings appear to be substantially harder near their surfaces than in the mass of material, and such materials may respond quite differently to stress applied at different levels near the surface. This finding has important implications for all coating properties that are strongly influenced by the surface. A quantity called ‘micro mar resistance' is defined. It may be useful for comparing different coatings under specified conditions of marring. However, there can be no single quantity that expresses ‘mar resistance' of a coating under all conditions.     

Synthesis and characterization of poly(1,8-diethynylnaphthalene)

Summary The cyclopolymerization of 1,8-diethynylnaphthalene(DEN) and its copolymerization with diethyl dipropargylmalonate(DEDPM) were carried out by various transition metal catalysts. MoCl₅-based catalyst was found to be very effective and gave almost a quantitative polymer yield. The resulting dark-brown homopolymer(PDEN) was partially soluble in chloroform, tetrahydrofuran, and dimethyl sulfoxide, whereas copolymer (1:1) with number avaerage molecular weight of 2.1x10⁴ by GPC showed good solubility in those solvents. The structure of the polymers was analysed by IR, NMR, and UV-VIS spectroscopies. From the spectral and solubility data, it is proposed that cyclized products with the conjugated system are formed. Room temperature conductivities of the I₂-doped homo and copolymer were found to be about 7.5x10^-3 and 5.1x10^-3 S/cm, respectively.