Catalytic Oxidative Dehydrogenation of Propaneand Isobutane over Rare Earth Oxyfluorides

稀土氟氧化物在丙烷、异丁烷氧化脱氢中的催化作用张伟德＊洪碧凤古萍英万惠霖蔡启瑞（厦门大学化学系，固体表面物理化学国家重点实验室，物理化学研究所厦门361005）关键词丙烷，异丁烷，催化氧化脱氢，稀土氟氧化物1997-10-06收稿，1998-01-0...Three rare earth oxyfluorides Sm2O3/4CeF3, Nd2O3/4CeF3 and Y2O3/4CeF3 were prepared.They were active in oxidative dehydrogenation of propane and isobutane with high selectivity to propene and isobutene.The propane is easier to dehydrogenate than isobtuane, and the isobutane is easier to crack.XRD measurements indicated the existence of new phase such as CeO2 and REF3 or REof as a result of the exchange between F- and O2- during the preparation.The insitu Raman spectra implied that O-2 was the active species.国家自然科学基

无偿献血者中隐匿性乙型肝炎病毒感染及表面抗原突变分析

采用多种免疫学检测和核酸检测相结合的方法调查了我国南方某城市无偿献血者中隐匿性乙型肝炎病毒(HBV)感染的存在情况。结果在9023例乙肝表面抗原(HBsAg)阴性的无偿献血者中,共发现17例HBV DNA阳性,隐匿性HBV感染者的发生率为0.19%(95%CI:0.11～0.30%)。序列分析显示其中6例在HBsAg"a"表位(aa124～aa147)存在不同程度氨基酸突变,突变发生率为42.9%(6/14,有3例未扩增出"a"表位片段序列),G145R突变是该地区隐匿性HBV携带者中发生频率最高的突变(4/6,66.7%)。隐匿性HBV感染者中基因型C的比例(10/17)显著高于HBsAg阳性的HBV感染者(0/15,P<0.01)

叠层亚波长减反结构及其制备方法

本发明揭示了一种叠层亚波长减反结构,包括在需要减反的高折射率材料自身表面通过蚀刻形成的亚波长图形,以及在前述亚波长图形表面经沉积生长的介质层,二者共同构成该叠层亚波长结构,其结构图形根据所用材料的折射率分布和所要减反的入射光波长和角度范围计算得到。本发明亚波长减反结构应用于高折射率表面的有源光电器件,能确实有效实现宽谱广角透射效果。较之于现有技术,本发明能有效钝化亚波长减反结构,减少非辐射复合中心,抑制非辐射复合损失,有效增加相应光电器件性能;并且,鉴于空气、介质材料和衬底材料折射率依次变化,故而采用叠层亚波长减反结构还能减弱制备难度,或在相同制备情况下获得更好的减反性能

Loss-Reduction in Flexibly Vertical Coupled Ring Lasers Through Asymmetric Double Shallow Ridge and ICP/ICP Cascade Etching

Loss-reduction in flexibly vertical coupled ring lasers is demonstrated through asymmetric double shallow ridge in the main ring area and inductively coupled plasma (ICP)/ICP cascade etching. Compared with the previous counterpart, the reduced threshold current and enhanced output power are obtained; coupling ratio is tuned from 27% to 1.5% when threshold current is varied from 60 to 80 mA. Single-mode lasing with sidemode-suppression ratio of 27 dB and quality factor of 13120 is achieved when I(c) = 1.5 mA, I(d) = 58 mA, which are nearly twofolds of that in the previous one. Such strategies can he widely employed to reduce loss in other vertical coupled photonic circuits