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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... 相似文献
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Hinch AG Tandon A Patterson N Song Y Rohland N Palmer CD Chen GK Wang K Buxbaum SG Akylbekova EL Aldrich MC Ambrosone CB Amos C Bandera EV Berndt SI Bernstein L Blot WJ Bock CH Boerwinkle E Cai Q Caporaso N Casey G Cupples LA Deming SL Diver WR Divers J Fornage M Gillanders EM Glessner J Harris CC Hu JJ Ingles SA Isaacs W John EM Kao WH Keating B Kittles RA Kolonel LN Larkin E Le Marchand L McNeill LH Millikan RC Murphy A Musani S Neslund-Dudas C Nyante S Papanicolaou GJ Press MF Psaty BM 《Nature》2011,476(7359):170-175
Recombination, together with mutation, gives rise to genetic variation in populations. Here we leverage the recent mixture of people of African and European ancestry in the Americas to build a genetic map measuring the probability of crossing over at each position in the genome, based on about 2.1 million crossovers in 30,000 unrelated African Americans. At intervals of more than three megabases it is nearly identical to a map built in Europeans. At finer scales it differs significantly, and we identify about 2,500 recombination hotspots that are active in people of West African ancestry but nearly inactive in Europeans. The probability of a crossover at these hotspots is almost fully controlled by the alleles an individual carries at PRDM9 (P?value 10(-245)). We identify a 17-base-pair DNA sequence motif that is enriched in these hotspots, and is an excellent match to the predicted binding target of PRDM9 alleles common in West Africans and rare in Europeans. Sites of this motif are predicted to be risk loci for disease-causing genomic rearrangements in individuals carrying these alleles. More generally, this map provides a resource for research in human genetic variation and evolution. 相似文献
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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. 相似文献
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