Assessment of Microscale Test Methods of Peeling and Splitting along Surface of Thin-Film/Substrates

Peel test methods are assessed through being applied to a peeling analysis of the ductile film/ceramic substrate system. Through computing the fracture work of the system using the either beam bend model (BB model) or the general plane analysis model (GPA model), surprisingly, a big difference between both model results is found. Although the BB model can capture the plastic dissipation phenomenon for the ductile film case as the GPA model can, it is much sensitive to the choice of the peeling criterion parameters, and it overestimates the plastic bending effect unable to capture crack tip constraint plasticity. In view of the difficulty of measuring interfacial toughness using peel test method when film is the ductile material, a new test method, split test, is recommended and analyzed using the GPA model. The prediction is applied to a wedge-loaded experiment for Al-alloy double-cantilever beam in literature.

Dual-wavelength distributed feedback laser for CWDM based on non-identical quantum well

Using non-identical quantum wells as the active material, a new distributed-feed back laser is fabricated with period varied Bragg grating. The full width at half maximum of 115 nm is observed in the amplified spontaneous emission spectrum of this material, which is flatter and wider than that of the identical quantum wells. Two wavelengths of 1.51 mu m and 1.53 mu m are realized under different work conditions. The side-mode suppression ratios of both wavelengths reach 40 dB. This device can be used as the light source of coarse wavelength division multiplexer communication systems.

Bromophenols coupled with nucleoside bases and brominated tetrahydroisoquinolines from the red alga Rhodomela confervoides

Three new bromophenols C-N coupled with nucleoside base derivatives (1-3) and three new brominated 1,2,3,4-tetrahydroisoquinolines (5-7, together with a new brominated tyrosine derivative (4, have been isolated from polar fractions of an ethanolic extract of the red alga Rhodomela confervoides. By spectroscopic and chemical methods including HRMS and 2D NMR data, their structures were determined as 7-[3-bromo-2-(2,3-dibromo-4,5-dihydroxybenzyl)-4,5-dihydroxybenzyl]-3,7-dihydro-1H-purine-2,6-dione (1), 7-(2,3-dibromo-4,5-dihydroxybenzyl)-3,7-dihydro-1H-purine-2,6-dione (2, 9-[3-bromo-2-(2,3-dibromo-4,5-dihydroxybenzyl)-4,5-dihydroxybenzyl]adenine (3), (-)-8S-(3-bromo-5-hydroxy-4-methoxy)phenylalanine (4), (-)-3S-8-bromo-6-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid (5), methyl (-)-3S-8-bromo-6-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate (6), and methyl (-)-3S-6-bromo-8-hydroxy-7-methoxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylate (7). Compounds 5-7 were semisynthesized by using 4 as the starting material.