Relationship between Colored Microstructure under Polarized Light and Shape Recovery Characteristics on the Thermomechanical Cycled CuAlNi Single Crystals

The paper studied the relationship between microstructure and shape recovery characteristics by using colored microstructure analysis under polarized light on the thermomechanical cycled CuAlNi single crystals. The two-way shape memory effect in quenched thin bar resulted from the preferential formation/extinction of martensite variant due to the internal quench stress, and the variant was formed at an angle of about 45 deg. with the tension direction ([001] of the βphase). Initial thermomechanical cycling under relatively low stress single variant stress-induced martensite was formed at an angle of 45 deg. with the tension and its morphology was a lath of parallel twins. More than one group of variants were formed after several training cycles and such variants also caused tilting of some thermally formed accommodated martensite. By overheating the trained sample containing stabilized multi-variants of stress-induced martensite, very coarse martensite structure with a strong asymmetry was produced, which caused the reverse two-way shape memory effect.

Simulation of Fast-Recovery Cross-Modulation Characteristics in Semiconductor Optical Amplifier with Assist Light

We analyzed the characteristics of cross-modulations (XM) and their recovery times in a semiconductor optical amplifier by a newly-developed TMM. The calculated results suggest faster recovery of the XMs by introducing a high-power assist light.

Carbonaceous matter in glacier at the headwaters of the Yangtze River:Concentration,sources and fractionation during the melting process

Carbonaceous matter has an important impact on glacial retreat in the Tibetan Plateau,further affecting the water resource supply.However,the related studies on carbonaceous matter are still scarce in Geladaindong(GLDD)region,the source of the Yangtze River.Therefore,the concentration,source and variations of carbonaceous matter at Ganglongjiama(GLJM)glacier in GLDD region were investigated during the melting period in 2017,which could deepen our understanding on carbonaceous matter contribution to glacier melting.The results showed that dissolved organic carbon(DOC)concentration of snowpit samples(283±200μg/L)was much lower than that of precipitation samples(624±361μg/L),indicating that large parts of DOC could be rapidly leached from the snowpit during the melting process.In contrast,refractory black carbon(rBC)concentration measured by Single Particle Soot Photometer of snowpit samples(4.27±3.15μg/L)was much higher than that of precipitation samples(0.97±0.49μg/L).Similarly,DOC with high mass absorption cross-section measured at 365 nm value was also likely to enrich in snowpit during the melting process.In addition,it was found that both r BC and DOC with high light-absorbing ability began to leach from the snowpit when melting process became stronger.Therefore,rBC and DOC with high light-absorbing ability exhibited similar behavior during the melting process.Based on relationship among DOC,rBC and K^+ in precipitation,the main source of carbonaceous matter in GLJM glacier was biomass burning during the study period.