A numerical model for Type II supernovae — The collapse stage

We use the following numerical model for the collapse stage of a Type II supernova of 15 M_⊙. Our electron capture rate includes the effects of the inverse reaction and the neutron-proton mass difference. This decreases the electron density at the collapse stage and led to rather large values of the maximum inward velocity and of the corresponding mass (Umax = 3.06 × 10⁹cm/s, Mmax=0.76 M_⊙). These larger values are more favourable for the propagation of shock after the rebounce and the triggering-off of a Type-II supernova explosion. For neutrino transport, we use a leakage model and an equilibrium diffusion model, respectively, for the thin and thick stages and a grey atmosphere model to assess the effect of neutrino precipitation on the collapse. We found this effect to be small, the energy precipitation to be not more than 10^?5 the neutrino energy loss and the momentum precipitation not more than 10^?6 the gravitational acceleration.     

PROPAGATION OF 30—60 DAY LOW FREQUENCY OSCILLATIONS AND THEIR INFLUENCE UPON THE SUBTROPICAL WESTERLIES JET STREAM DURING NORTHERN HEMISPHERE WINTER

Based on daily ECMWF gridpoint data of two winters during 1981—1983 including an ENSOyear,propagation of low frequency oscillations(LFO)during Northern Hemisphere winters andtheir influences upon 30—60 day oscillations of the subtropical jet stream are studied with the sta-tistical methods as complex empirical orthogonal function(CEOF)and so on.Results show that inthe winter of a normal year(1981—1982),30—60 day oscillations in the subtropical zone aremainly in the northern and southern flanks of exit region of jet stream.In the ENSO year(1982—1983),they are mainly in the vicinity of entrance and exit regions of jet stream.Intraseasonalchanges of subtropical jet stream manifested themselves as latitudinal fluctuation or longitudinalprogression or regression of about 40 day period.There are marked differences between propagat-ing passages of low frequency modes responsible for changes of subtropical jet stream in the normalyear(1981—1982)and in the ENSO year(1982—1983).Changes of oscillation amplitude showobvious phases.In general,the one in late winter is stronger than that in early winter,strongestone occurs in February.     

On the microwave millisecond spike emission and its associated phenomena during the impulsive phase of large solar flare

We propose a model of two acceleration regions, which can explain, on the basis of microwave maser caused by a “hollow-beam” distribution of electrons, the presence of millisecond spikes in the event of 1981 May 16 and their absence in the event of 1981 October 12, and the enhanced continuous emission in the latter. We have also uncovered relations among the features, e.g. the Type III_G, Type IV_DCIM and hard x-ray bursts, that accompany the microwave millisecond spikes during the impulsive phase of a large flare.     

海水中微量元素无机离子交换动力学研究——液膜递进模型理论 Ⅰ.天然海水条件下

最近十几年来,海水物理化学中关于海水的化学热力学研究已较广泛地开展,并已有一些重要的研究结果报导。但是,关于海水中化学动力学的研究,至今却基本上仍属空白。然而这正是海洋中许多化学过程(特别像海水化学资源开发、海洋污染和防治等实践性比较强的领域中)要解决的关键问题。本文是我们从事这一方面研究工作的第一篇报导,讨论的内容是海洋中最重要的过程之一——无机离子交换过程。     

黑鲷早期鳞被的形成

黑鲷Sparus macrocephalus(Basilewsky)幼苗鳞被最早出现的部位是在躯干部胸鳍基后至肛门直上方的侧线处。黑鲷只具一个鳞被起始中心。最早出现鳞片的个体为体长9.5—14.1mm,平均11.51±0.85mm,全长11.2—16.5mm,平均13.65±1.01mm,孵后日龄23—35d。鳞被发育完全时的最小个体为体长12.1—18.5mm,平均14.57±1.55mm,全长14.8—23.5mm,平均17.99±2.17mm,孵后日龄27—42d。     

塞曼石墨炉原子吸收法直接测定海水中的铬

海水基体对Cr有增感作用。本文研究了抗坏血酸、柠檬酸三铵、酒石酸、乙酸铵等有机基体改进剂对消除基体干扰效果。前二者均有效地消除基体干扰,但1％抗坏血酸 1％柠檬酸三铵混合试剂的效果更好,它不仅可以消除基体干扰,还可降低背景及噪声,Cr的吸收峰也较平滑。本法准确,相对偏差在0.7—4.4％范围内。回收率在92—109％范围内。若海水Cr含量低于定量下限时,可采用多次进样法。