InAs0.3Sb0.7 films grown on (100) GaSb substrates with a buffer layer by liquid-phase epitaxy

The growth of InAsxSb1-x films on (100) GaSb substrates by liquid-phase epitaxy (LPE) has been investigated and epitaxial InAs0.3Sb0.7 films with InAs0.9Sb0.09 buffer layers have been successfully obtained. The low X-ray rocking curve FHWM values of InAs0.3Sb0.7 layer shows the high quality of crystal-orientation structure. Hall measurements show that the highest electron mobility in the samples obtained is 2.9 x 10(4) cm(2) V-1 s(-1) and the carrier density is 2.78 x 10(16)cm(-3) at room temperature (RT). The In As0.3Sb0.7 films grown on (10 0) GaSb substrates exhibit excellent optical performance with a cut-off wavelength of 12 mu m. (c) 2007 Elsevier B.V. All rights reserved.

Growth and spectroscopic characteristics of Yb : LPS single crystal

For the first time, a high optical quality Yb3+-doped lutetium pyrosilicate laser crystal Lu2Si2O7 (LPS) was grown by the Czochralski (Cz) method. The segregation coefficient of ytterbium ion in Yb:LPS crystal detected by the inductively coupled plasma atomic emission spectrometer (TCP-AES) method is equal to 0.847. X-ray powder diffraction result confirms the C2/m phase monoclinic space group of the grown crystal and the peaks corresponding to different phases were indexed. The absorption and fluorescence spectra, as well as fluorescence decay lifetime of Yb3+ ion in LPS have been investigated. The absorption and fluorescence cross-sections of the transitions F-2(7/2) <-> F-2(5/2) of Yb3+ ion in LPS crystal have been determined. The advantages of the Yb:LPS crystal including high crystal quality, quasi-four-level laser operating scheme, high absorption cross-sections (1.33 x 10(-2) cm(2)) and particularly broad emission bandwidth (similar to 62 nm) indicated that the Yb:LPS crystal seemed to be a promising candidate used as compact, efficient thin chip lasers when LD is pumped at 940 and 980 nm due to its low-symmetry monoclinic structure and single crystallographic site. (c) 2007 Elsevier B.V. All rights reserved.

InAs0.3Sb0.7 films grown on (100) GaSb substrates with a buffer layer by liquid-phase epitaxy

The growth of InAsxSb1-x films on (100) GaSb substrates by liquid-phase epitaxy (LPE) has been investigated and epitaxial InAs0.3Sb0.7 films with InAs0.9Sb0.09 buffer layers have been successfully obtained. The low X-ray rocking curve FHWM values of InAs0.3Sb0.7 layer shows the high quality of crystal-orientation structure. Hall measurements show that the highest electron mobility in the samples obtained is 2.9 x 10(4) cm(2) V-1 s(-1) and the carrier density is 2.78 x 10(16)cm(-3) at room temperature (RT). The In As0.3Sb0.7 films grown on (10 0) GaSb substrates exhibit excellent optical performance with a cut-off wavelength of 12 mu m. (c) 2007 Elsevier B.V. All rights reserved.

FATE OF 2 PHENYLBENZOYLUREA INSECTICIDES IN AN ALGAE CULTURE SYSTEM (SCENEDESMUS-SUBSPICATUS)

The bioaccumulation, elimination and degradation of C-14-labelled diflubenzuron (DFB) and of 1-(2-chlorobenzoyl)-3-(4-chlorophenyl)urea (CCU) was studied in a laboratory algae culture system of scenedesmus subspicatus. Algae were exposed at an initial concentration of 200 mug/l for seven days. Neither substance had an inhibitory effect on the growth of algae. The half life of DFB and CCU was 3 and 1 days, respectively, as measured by HPLC. The distribution of C-14 between medium and algae was measured. In the case of DFB radioactivity in algae increased steadily and levelled off at approximately 60 % after 5 days. Due to algae growth BCF values decreased from 4310 to 889 for DFB and from 6719 to 304 for CCU during the exposure period. The relationship between algae density and bioconcentration could be correlated by an adsorption isotherm. Elimination of both compounds was rapid during the first hours.

Phase transition temperature of HPT(2,3,6,7,10,11-hexa-n-pentyloxytriphenylene) from molecule dynamic simulation

Molecule dynamics simulation was used on HPT(2,3,6,7,10,11-hexa-n-pentyloxytriphenylene), which is a discotic Liquid crystal. From analyzing the energy and displacement varying with the temperature, the phase transition temperature of PM6MPP can be predicted. The deviations of T-g, T-m and T-i due to the MD time scale are small enough that it should be possibly used to predict the material properties especially when more powerful computers are available.