阳极氧化制备铝磁性膜的研究

对阳极氧化技术制备铝磁性膜进行了实验研究。用ＳＥＭ，ＥＳＣＡ，ＲＢＳ等表面分析手段对Ａｌ磁性膜的形貌、大小、厚度以及磁性膜中的元素分布作了分析，并测量了不同工艺条件下磁性膜的矩形比。     

Estimating fertility rates using the ONS Longitudinal Study--what difference does the inclusion of non-continually resident members make?

Among datasets available for fertility research in England and Wales, the Office for National Statistics (ONS) Longitudinal Study (LS) is unique in its construction and scale. The large number of individuals who are part of the study means that it is an important dataset for estimating fertility trends in England and Wales by age and parity. This article uses the LS to estimate age-specific fertility rates (ASFRs) for England and Wales between 1991 and 2001. This necessitates great care to ensure that the exposure to risk of birth for female LS members is fully understood. To achieve this, two forms of residential history are defined - consistent cases where the residential information for the LS member is potentially complete for the whole decade and inconsistent cases where there is certainly some form of incompleteness in the residence information. By considering 'all consistent cases', that is both the continuously resident plus those who are not continuously resident but appear to have a complete residential history, we obtain ASFRs which are slightly lower than official statistics figures, but closer to these official figures than ASFRs produced when restricting the sample to LS members who remain continuously resident between 1991 and 2001. The fertility of those consistent cases who are not continuously resident is substantially higher than the rates of continuously resident cases.     

Unexpected inhibition of fusion in nucleus-nucleus collisions

Unstable heavy atomic nuclei not found in nature can be created by fusing two stable nuclei, in a process analogous to colliding charged droplets of liquid. Recently, the formation of a handful of super-heavy nuclei with atomic numbers 114 (ref. 1) and 116 (ref. 2) has been achieved by fusion of heavy nuclei. The electrostatic energy of such systems is very large (which is the reason super-heavy nuclei are unstable), so although the two nuclei may initially be captured by the nuclear potential, rather than fusing, they almost always separate after transfer of mass to the lighter nucleus. This process, called quasi-fission, can inhibit fusion by many orders of magnitude. Understanding this inhibition may hold the key to forming more super-heavy elements. Theoretically, inhibition is predicted (ref. 5 and references therein) when the product Z1Z2 of the charges of the projectile and target nuclei is larger than about 1,600. Here we report measurements of three fusion reactions with Z1Z2 around half this value, each forming 216 88Ra. We find convincing model-independent evidence both of inhibition of fusion, and of the presence of quasi-fission. These results defy interpretation within the standard picture of nuclear fusion and fission.