利用GCV优化的正则化方法对硬X射线望远镜图象重建研究

图象重建是一个求逆过程具有不适定性。本文介绍的是一种从少数投影数据进行图象重建的线性代数法－Ｐｈｉｌｌｉｐｓ－Ｔｉｋｈｏｎｏｖ正则化方法,同时选择优化工具ＧＣＶ确定最优的正则参数。为验证该方法,我们对日本Ｙｏｈｋｏｈ卫星上塔载的硬Ｘ射线望远镜（ＨＸＴ）拍摄的太阳图象进行重建。     

冷空气降温强度的垂直分布

我们在研究武夷山区降温强度时,发现冷空气降温强度并不是地面最大,而是随拔海高度升高而增强,在1.000—1,200米处达到最大,以上又开始减弱,即出现极大值型的分布。这种现象对冷空气活     

本刊加入万方数据(ChinaInfo)系统科技期刊群的声明

为了实现科技期刊编辑、出版发行工作的电子化,推进科技信息交流的网络化进程,我刊现已入网"万方数据(ChinaInfo)系统科技期刊群",所以,向本刊投稿并录用的稿件文章,将一律由编辑部统一纳入万方数据(ChinaInfo)系统,进入因特网提供信息服务.凡有不同意者,请另投它刊.本刊所付稿酬包含刊物内容上网服务报酬,不再另付.     

Effect of bis(tributyltin) oxide on reproduction and population growth rate of calanoid copepod Schmackeria poplesia

A full life-cycle toxicity test, combined with histology, on calanoid copepod Schmackeria poplesia was used to study the effect of bis(tributyltin) oxide (TBTO). The results indicate no sex-specific differences in TBTO toxicity. Long-term mortalities of the copepods exposed to concentrations higher than 20 ng TBTO L⁻¹ were significantly elevated compared with that of control, and larval development was inhibited when they were exposed to 40 and 60 ng TBTO L⁻¹. The percentages of ovigerous females were reduced compared with the control (P<0.01) after 24 days exposure to concentrations higher than 10 ng TBTO L⁻¹. Histological examinations suggest that exposure to TBTO might block the posterior end of the diverticula and inhibits the production of egg sacs. A modified Euler-Lotka equation was used to calculate a population-level endpoint, the intrinsic rate of natural increase (r _m), from individual life-table endpoints, i.e. mortality rate, time of release of first brood, sex ratio, the fraction of ovigerous females among all females as well as the number of nauplii per ovigerous female. Apart from the highest TBTO concentration (60 ng L⁻¹), where all females aborted their egg sacs, 20 ng TBTO L⁻¹ was the only concentration that significantly decreased r _m compared with that of control (an effect associated with decreased sex ratio). The results show that the S. poplesia is affected by prolonged exposure to low concentrations of TBTO. The full life-cycle toxicity test combined with histology experiments provides more integral understanding of the toxicity of endocrine disrupters.     

莱州湾东部金的金属量异常

据莱州湾东部刁龙咀-龙口市海域海底表层沉积物中金的金属量测试资料，于区内圈定了6处金的金属量异常，经对该区内地质钻孔沉积物金的金属量测试分析，发现23处金的金属量异常，本文论述了这些异常的分布及特征．     

ODP191航次--西北太平洋地震观测和冲击钻工程检验

大洋钻探191航次由两部分组成:(1)在西北太平洋深海海底(WP-2站位)钻探并下套管,同时将安装用于长期浅海底钻孔观测的宽频道地震检波器;(2)硬岩石重反装置(HRRS)以及其他设备的工程检验.     

新千年寄语

千禧龙年 ,一个充满希望的 2 1世纪拉开了帷幕 ,人类社会又将奏响科学技术进步的新乐章 ,一个崭新、灿烂的新时代等待我们再创辉煌。《海洋地质与第四纪地质》2 0 0 0年以新的形象与您见面了 ,这是读、作者高层次的需要 ,也是时代发展的必然 ,我们诚望继续得到广大读、作者和社会各界的支持与厚爱。同时 ,也希望《海洋地质与第四纪地质》生机似龙腾 ,新世纪有一个良好的开端。《海洋地质与第四纪地质》新版本为大 1 6开 ,彩印封页 ,设置 :院士论坛 (不定期 )、沉积与环境、地球化学与地球物理、古海洋与年代地质、油气与矿产、第四纪地质、…     

废柴油加热炉

废柴油加热炉代替过去烧煤炭的烘炉。主要可利用来加热直径50毫米的钻杆,若能与墩管机、滚丝机配套使用,效果更好。