Prevalence of Epidermal Conditions in Critically Endangered Indo-Pacific Humpback Dolphins (Sousa chinensis) from the Waters of Western Taiwan

The prevalence of epidermal conditions in a small critically endangered population (<100 individuals) of coastal Indo-Pacific humpback dolphins (Sousa chinensis) from the waters of western Taiwan was assessed during a photo-identification study conducted between 2006 and 2010. Of 97 individuals photographically examined, 37% were affected by one or multiple conditions. Besides, mature individuals had significantly higher prevalence than immature ones. Five different skin condition categories were considered, including pox-like lesion, pale lesion, orange film, prolonged ulcer lesion, and nodule on body. This first study to investigate epidermal conditions on S. chinensis in the world offers data for comparison with other studies in the future and new ground for discussion on the health of these animals and the potential impact of anthropogenic activities

Growth mechanism in the multiple buffer layer of GaN on sapphire by organometallic vapor phase epitaxy

[[abstract]]High-quality GaN epitaxial layers with a multiple-pair buffer layer have been grown on sapphire substrates in a separate-flow reactor by metalorganic chemical vapor deposition. Each pair of buffer layers consists of a 300 Å thick GaN nucleation layer grown at a low temperature of 525°C and a 1-4 μm thick GaN epitaxial layer grown at a high temperature of 1000°C. The GaN samples with a multiple-pair buffer layers are characterized by etch-pit density and cross-section TEM measurements. In this experiment, the regions grown on multiple buffer layers were thoroughly examined. Cross-section TEM clearly revealed characteristic defects along the [112¯0] direction in the various pairs of buffer-layer grown regions. We observed the interface of buffer layer and buffer layer, where most vertical dislocations can be terminated in the interface, and few dislocation were repropagated in the subsequent buffer-layer growth. The influence of multiple buffer structure and the dislocation distribution near the buffer-layer interface are discussed[[fileno]]2030154030003[[department]]電機工程學

Improvement of diode performance with multiple-pair buffer layer by MOCVD

[[abstract]]The GaN homo-junction light-emitting diodes (LEDs) with a multiple-pair buffer layer (MBL) were grown by metalorganic vapor phase epitaxy on sapphire substrates. Each pair of the buffer layer consists of a 300 Å thick GaN nucleation layer grown at a low temperature of 525°C and a 4 μm thick GaN epitaxial layer grown at a high temperature of 1025°C. It is found that the GaN LEDs with a three-pair buffer layer will exhibit a low turn-on voltage, stronger electroluminescence intensity and higher light-output power as compared to the conventional growth without a buffer layer. This is attributed to the effective reduction in the propagation of defects and dislocations near the p-n junction for the LEDs with MBL[[fileno]]2030154030004[[department]]電機工程學

Low-temperature crack resistance of TB gravel asphalt mixture

The prepared TB asphalt was used for mix design of gravel asphalt mixture, and low-temperature crack resistance performance of the TB asphalt gravel mixture was evaluated based on small beam bending test, and compared with matrix asphalt gravel mixture. The results showed that the viscoelasticity of TB asphalt suffered a certain loss when it was prepared at a higher temperature, and its softening point was slightly higher, but low-temperature performance and storage stability were excellent. The density of TB asphalt was smaller than that of base asphalt, so the optimal asphalt amount for TB gravel asphalt mixture was larger. The strain energy density of TB asphalt gravel mixture was 68%, 147% and 65% higher than that of matrix gravel asphalt mixture at 0 ℃, -10 ℃ and -25 ℃ respectively. The temperature at which brittle failure occurs was around 0 ℃ for gravel asphalt mixture, while -25 ℃ for TB gravel asphalt mixture. TB asphalt effectively improved the low-temperature crack resistance of gravel asphalt mixture