多系统萎缩（multiple system atrophy,MSA）是一种成年起病、进展性的神经系统变性疾病,表现为不同程度的自主神经功能障碍、对左旋多巴类药物反应不良的帕金森综合征、小脑性共济失调及锥体束征等临床特征。由于起病时累及3个系统的...多系统萎缩（multiple system atrophy,MSA）是一种成年起病、进展性的神经系统变性疾病,表现为不同程度的自主神经功能障碍、对左旋多巴类药物反应不良的帕金森综合征、小脑性共济失调及锥体束征等临床特征。由于起病时累及3个系统的先后不同,临床表现复杂,可出现尿失禁、体位性低血压、运动迟缓、行走不稳等症状,还可能出现精神情感障碍[1],但合并特殊类型睡眠障碍患者少见。随着病程进展。展开更多
GaN-based thin film vertical structure light-emitting diodes （VS-LEDs） were fabricated by a modified YAG laser lift-off （LLO） process and transferred to Cu substrates. With a comparison of the electrical and optic...GaN-based thin film vertical structure light-emitting diodes （VS-LEDs） were fabricated by a modified YAG laser lift-off （LLO） process and transferred to Cu substrates. With a comparison of the electrical and optical properties of conventional LEDs on sapphire substrates and of lateral structure thin film LEDs by a KrF LLO process, the vertical structure of LLO LEDs shows obvious superiority. LLO VSLEDs made by modified YAG LLO process show less increase of leakage current than the devices made by conventional/（rE LLO process. Furthermore, owing to the well current spreading and less current path, the ideality factors and series resistance of vertical structure LEDs reduce greatly and the efficiency increases more obviously than the lateral structure LEDs, which is dso reflected on the relative L - I curves. The output power of vertical structure LEDs is over 3 times greater than that of the lateral structure LLO LEDs within 300mA.展开更多
Electrical characteristics of In0.05 Ga0.95N/Al0.07Ga0.9aN and In0.05 Ga0.95N/GaN multiple quantum well （MQW） ultraviolet light-emltting diodes （UV-LEDs） at 400hm wavelength are measured. It is found that for InGa...Electrical characteristics of In0.05 Ga0.95N/Al0.07Ga0.9aN and In0.05 Ga0.95N/GaN multiple quantum well （MQW） ultraviolet light-emltting diodes （UV-LEDs） at 400hm wavelength are measured. It is found that for InGaN/AlGaN MQW LEDs, both ideality factor and parallel resistance are similar to those of InGaN/GaN MQW LEDs, while series resistance is two times larger. It is suggested that the Al0.07Ga0.93N barrier layer did not change crystal quality and electrical characteristic of p-n junction either, but brought larger series resistance. As a result, InGaN/AlGaN MQW LEDs suffer more serious thermal dissipation problem although they show higher light output efficiency.展开更多
文摘多系统萎缩（multiple system atrophy,MSA）是一种成年起病、进展性的神经系统变性疾病,表现为不同程度的自主神经功能障碍、对左旋多巴类药物反应不良的帕金森综合征、小脑性共济失调及锥体束征等临床特征。由于起病时累及3个系统的先后不同,临床表现复杂,可出现尿失禁、体位性低血压、运动迟缓、行走不稳等症状,还可能出现精神情感障碍[1],但合并特殊类型睡眠障碍患者少见。随着病程进展。
基金Supported by the National Natural Science Foundation of China under Grant Nos 61006035, 61076012, 60676032 and 60607003, the National Key Basic Research Program of China under Grant No TG-2007CB307004, the National High-Tech Research and Development Program of China under Grant No 2009AA03A198, and the Postdoctoral Science Foundation of China under Grant No 20090460168
文摘GaN-based thin film vertical structure light-emitting diodes （VS-LEDs） were fabricated by a modified YAG laser lift-off （LLO） process and transferred to Cu substrates. With a comparison of the electrical and optical properties of conventional LEDs on sapphire substrates and of lateral structure thin film LEDs by a KrF LLO process, the vertical structure of LLO LEDs shows obvious superiority. LLO VSLEDs made by modified YAG LLO process show less increase of leakage current than the devices made by conventional/（rE LLO process. Furthermore, owing to the well current spreading and less current path, the ideality factors and series resistance of vertical structure LEDs reduce greatly and the efficiency increases more obviously than the lateral structure LEDs, which is dso reflected on the relative L - I curves. The output power of vertical structure LEDs is over 3 times greater than that of the lateral structure LLO LEDs within 300mA.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60676032, 60577030, and 60476028, and the National Key Basic Research Special Foundation of China under Grant No TG 2007CB307004.
文摘Electrical characteristics of In0.05 Ga0.95N/Al0.07Ga0.9aN and In0.05 Ga0.95N/GaN multiple quantum well （MQW） ultraviolet light-emltting diodes （UV-LEDs） at 400hm wavelength are measured. It is found that for InGaN/AlGaN MQW LEDs, both ideality factor and parallel resistance are similar to those of InGaN/GaN MQW LEDs, while series resistance is two times larger. It is suggested that the Al0.07Ga0.93N barrier layer did not change crystal quality and electrical characteristic of p-n junction either, but brought larger series resistance. As a result, InGaN/AlGaN MQW LEDs suffer more serious thermal dissipation problem although they show higher light output efficiency.
