[Infrared Spectral Characteristics of Ambers from Three Main Sources (Baltic, Dominica and Myanmar)].

Infrared spectra of ambers from Baltic, Dominica and Myanmar are obtained by Specular Reflection and KBr Pellet Transmission Methods. Although the infrared spectra of these ambers present similar features for ambers from different locations, refined differences in location and intensity of absorption peaks could be identified among them. Between 3000 and 2800 cm(-1), two obvious bands with a weak shoulder peak are seen in the Baltic amber spectrum, whereas there are two bands in the Dominica's and three bands in the Myanmar's.

InGaAs-InP avalanche photodiodes with dark current limited by generation-recombination.

Separate absorption grading charge multiplication avalanche photodiodes (SAGCM APDs) are widely accepted in photon starved optical communication systems due to the presence of large photocurrent gain. In this work, we present a detailed analysis of dark currents of planar-type SAGCM InGaAs-InP APDs with different thicknesses of multiplication layer. The effect of the diffusion process, the generation-recombination process, the tunneling process and the multiplication process on the total leakage current is discussed.

[Microcalorimetric investigation of two cephalosporins on colon bacteria activity].

The effects of cephradinum and ceftazidime on the metabolism of Escherichia coli (E. coli) DH5alpha was determined by microcalorimetry. The microbial activity was recorded as power-time curves through an ampoule method with a TAM Air Isothermal Microcalorimeter at 37 degrees C.