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.     

利用降水平均递增率求山地最大降水高度

本文引入降水平均递增率的概念,改进了文献中的计算方法,可以一次求出山地降水量与海拔的经验关系式中全部参数的最佳值,其中包括山地最大降水高度。并用实例说明了本法的步骤及特点。     

Considerations for conducting incubations to study the mechanisms of As release in reducing groundwater aquifers

Microbial Fe reduction is widely believed to be the primary mechanism of As release from aquifer sands in Bangladesh, but alternative explanations have been proposed. Long-term incubation studies using natural aquifer material are one way to address such divergent views. This study addresses two issues related to this approach: (1) the need for suitable abiotic controls and (2) the spatial variability of the composition of aquifer sands. Four sterilization techniques were examined using orange-colored Pleistocene sediment from Bangladesh and artificial groundwater over 8 months. Acetate (10 mM) was added to sacrificial vials before sterilization using either (1) 25 kGy of gamma irradiation, (2) three 1-h autoclave cycles, (3) a single addition of an antibiotic mixture at 1× or (4) 10× the typical dose, and (5) a 10 mM addition of azide. The effectiveness of sterilization was evaluated using two indicators of microbial Fe reduction, changes in diffuse spectral reflectance and leachable Fe(II)/Fe ratios, as well as changes in P-extractable As concentrations in the solid phase. A low dose of antibiotics was ineffective after 70 days, whereas autoclaving significantly altered groundwater composition. Gamma irradiation, a high dose of antibiotics, and azide were effective for the duration of the experiment.     

Vertical variations of wave-induced radiation stress tensor

INTRODUcrIONThe concept of radiation stress was deve1oPed by tonguet--Higgins and Stewart (1964 ),who intreduced the definition of radiation stress as the excess mornentum due to the presence ofwaves, on the basis of time-averaged laws of Newtonian fluid mechanics and the assmption ofa unifOrm velocity distribution over depth. Subequently, the theory has been applied success-fully in the investigation of phenomena such as wave set-up and set--down (Bowen et al.,l968), longshore currents …     

藻类分子生物技术两年评─—与藻类活性物质研究有关的生物技术

根据１９９２年６月－１９９４年６月国内外发表资料，评述海洋藻类活性物质研究的生物技术及最新成果。认为，海洋生物活性物质研究的重心正转向与海洋生物技术有关的研究。运用生物技术筛选、提取并生产藻类活性物质已经成为这一领域的主流。综合文献表明，藻类活性物质的生物技术正走向成熟，大量的活性物质被发现，光生物反应器将成为主要的下游生产技术，通过藻类基因工程生产药物已初现端倪。     

黄海海域陆相中生界地震反射特征及靶区优选

利用前人对黄海海域油气勘探成果，作者对北黄海盆地，南黄海盆地北部坳陷陆相中生界进行了研究。结果认为：黄海海域陆相中生界分布广、厚度大、具有良好的生、储、盖组合，是该区下步油气战略性调查的首选目标。并提出北黄海陆相中生界油气勘探应以东部凹陷为主，同时兼顾中部凹陷。南黄海北部坳陷近期油气勘探重点应选择北部凹陷和加大东北凹陷的研究力度。南黄海南部坳陷陆相中生界油气勘探重点放在南五和南七凹陷。     

萼花臂尾轮虫(Brachionus calyciflorus)COI基因序列变异及种群遗传结构分析

利用线粒体细胞色素氧化酶亚基Ⅰ(cytochrome oxidaseⅠ，COI)基因序列对北京地区和江汉湖群部分湖泊萼花臂尾轮虫(Brachionus calyciflorus)种群遗传结构进行了初步分析。以特异引物进行PCR扩增，获得了661bp的基因片断序列，所得序列与Genbank中B．calyciflorus COI序列的同源性为82％—93％。在6个种群中，共获得了15种单元型。序列分析结果表明，不同季节单元型之间的遗传距离较大(0．248-0．263)，而在同一季节单元型之间遗传距离较小(0．002-0．031)。种群遗传结构分析表明，各种群之间无共享的单元型，同一季节不同湖泊种群之间存在着一定程度的遗传分化，但未按照地理位置形成明显的地理格局。按采样时间分组进行AMOVA分析，组间差异高达94．09％；DH-I与其他种群之间存在着明显的遗传分化。同一湖泊不同季节样品之间，遗传变异较大，这表明在同一湖泊存在着不同基因型的轮虫休眠卵，当环境条件发生了变化后，不同基因型之间会发生更迭。     

太平洋三海区热液烟囱物的氧同位素特征及形成温度

使用氧同位素方法 ,测试了西太平洋马里亚纳岛弧、马里亚纳海槽、冲绳海槽和东太平洋加拉帕戈斯裂谷的海底热液烟囱和硫化物全岩样品。结果表明 :马里亚纳岛弧上的埃斯梅拉尔达破火山口的热液硫化物的形成温度最高 (达 2 75℃ ) ,而成为高温产物的代表 ;冲绳海槽和加拉帕戈斯裂谷烟囱 ,表现为中高温类型 ,其氧同位素温度在 1 5 0℃左右 ;马里亚纳海槽以蛋白石为主要矿物的烟囱物 ,则显示出典型的低温热液类型 ,少量黄铁矿砂试样则表现出中温类型特征。但上述区域大都不同程度地存在有闪锌矿、黄铁矿、黄铜矿等中高温热液矿物 ,说明研究区除马里亚纳海槽明显有中低温热液活动类型外 ,其它区域皆具备中高温热液活动特征     

南海西沙西南海域表层沉积物特征

西沙西南海域表层沉积物样品矿物成分，地球化学，微体古生物分析测试结果表明：沉积物可分为７种类型，沉积环境主要是陆坡，部分为深海平原，海洋生物，海洋化学以及火山物质的沉积起到了积极的作用，陆源物质的影响较小，它们主要来源于北部大陆和南部岛礁等物源区。