Investigations of ZnO thin films deposited by a reactive pulsed laser ablation

Highly transparent ZnO thin films were deposited at different substrate temperatures by pulsed laser deposition in an oxygen atmosphere.The thin films were characterized by various techniques including X-ray diffraction,scanning electron microscopy,optical absorption,and photoluminescence.We demonstrated that oriented wurtzite ZnO thin films could be deposited at room temperature using a high purity zinc target.Variable temperature photoluminescence revealed new characteristics in the band edge emission.The...     

FDTD计算功率变换器近场到近/远场的转换

从理论上分析了利用时间有限差分法由近场到近场或远场转换的频域和时域两种方法，并选择时域的方法计算在FDTD计算范围内一给定点的电场值，与直接利用FDTD法得到的结果相比较，两者非常一致；最后利用该方法计算了功率变换器FDTD计算范围外一给定点的电磁场时间响应．     

Malaria risk: estimating clinical episodes of malaria

Estimates of the disease burden caused by malaria are crucial for informing malaria control programmes. Snow and colleagues claim that their estimate of 515 million cases of malaria caused by Plasmodium falciparum globally is up to 50% higher than that reported by the World Health Organization (WHO), and 200% higher for areas outside Africa. However, this comparison refers to the WHO's estimates from 1990 and 1998, and not to the range of 300 million to 500 million that the WHO has used since 2000 (ref. 2). Both groups agree that the burden of malaria disease outside Africa, especially in South Asia, is greater than was estimated in the 1990s.