对铀矿勘探中所用分析方法的评价

本文的目标是集中研究已为国家和私人实验室实践过了的各种测铀方法。这里讨论的常用测铀方法有:(1)常规的荧光测量法;(2)中子活化分析法、缓发中子计数测量法;(3)X射线光谱法;(4)裂变径迹法;(5)激光激发荧光法;(6)分光光度法;(7)其他方法。这些常规方法中,荧光法和用缓发中子     

Distribution and characteristics of suspended particulate matter in a heavily eutrophic estuary, Tokyo Bay, Japan

Bulk suspended particulate matter (SPM), chlorophyll a (Chl a), ignition loss, particulate organic carbon (POC), organic nitrogen, inorganic phosphorus (PIP), and organic phosphorus were investigated in the heavily eutrophic Arakawa River estuary, Japan. Chl a was high (approximately 35 microg l(-1)) in summer and low (approximately 6.7 microg l(-1)) in winter and autumn. POC from living phytoplankton accounted for approximately 34% and approximately 70% of total POC during low- and high-biomass seasons, respectively. During the low-biomass season, detrital POC distribution was conservative, and less reactive, land-derived materials mainly composed particulate organic materials (POM), but complex mixing of land-derived POM and autochthonous planktonic detritus caused nonconservative detrital POC behavior during the high-biomass season. PIP concentration in SPM decreased with increasing salinity, likely by desorption of soluble orthophosphate (ortho-P). The ortho-P released from SPM, 56% of the ortho-P input from the Arakawa River to the bay, was a significant potential source of biologically available phosphorus causing eutrophication of coastal environments.     

Eutrophication in the Polish coastal zone: the past, present status and future scenarios

In the Baltic Sea eutrophication processes have accelerated in the past 50 years of the 20th century and presently there exists a major ecological problem for this sea. The Polish coastal zone of the southern Baltic Sea is the recipient of riverine inputs from two major sources, namely the Odra and Vistula, as well as a number of smaller rivers along the central coast. Hence, the entire coastal zone remains under severe anthropogenic pressure. The variability of nutrient concentrations, especially the winter nutrient pool in the euphotic zone, summer level of total nitrogen and total phosphorus, together with such eutrophication indicators as water oversaturation with oxygen and the summer oxygen minimum, were analysed in the data time series 1959-2001. The temporal trends were investigated using linear regression and the non-parametric Whirsch test. The future characteristics of the Baltic Sea are discussed taking into account the development of driving forces.     

A simple method to reduce discharge of sewage microorganisms from an Antarctic research station

The majority of coastal Antarctic stations release untreated sewage into the near-shore marine environment. This study examined bacterial reproduction within the temporary sewage-holding tanks of Rothera Research Station (Adelaide Island, Antarctic Peninsula) and monitored sewage pollution in the local marine environment. By continuously flushing the sewage-holding tanks with cold seawater we inhibited microbial reproduction and decreased the numbers of bacteria subsequently released into the sea by >90%. The widespread use of this simple method could significantly reduce the numbers of faecal coliform and other non-native microorganisms introduced into the Antarctic marine environment.     

Chronic effects of tributyltin on the caprellid amphipod Caprella danilevskii

In order to examine the biological effects by TBT exposure, experiments involving the exposure of five levels of TBT concentrations (0, 10, 100, 1000 and 10,000 ngl(-1)) were conducted on the caprellid amphipod Caprella danilevskii, over a generation after hatching. Marked delays in growth and molting during the early developmental stage and maturation were found in both 100 and 1000 ng TBTCl l(-1) concentrations in spite of the sex. All specimens died in 10,000 ng TBTCl l(-1) within 4 days after hatching. Inhibition of maturation and reproduction such as delaying in the achievement of maturity and a decrease in the number of juveniles hatched was apparent in 10 and 100 ng TBTCl l(-1) concentrations. Furthermore, brood loss, and failure in egg formation and hatching were observed as the TBT concentration became higher. No significant changes in sex ratio were seen at any of the TBT exposure levels during hatching and maturation in the present study. This phenomenon was different from a previous study in which the proportion of females was increased with an increase in TBT concentrations in the embryonic exposure experiment. This suggests that sex disturbance is induced during the embryonic stage of the species. A drastic decrease in survival rate was observed at 10 ng TBTCl l(-1) (25%) which corresponds to the mean level in coastal waters. Therefore, the present encountering ambient TBT concentration may influence populations of C. danilevskii in the coastal environment.     

OHP数据中心

海洋半球计划(OHP)台网是一个覆盖以前观测密度低的西太平洋区域的地球物理观测台网。该台网是集地震、GPS、地磁和超导重力观测于一体的台网。联合使用该台网与以前所建台网的资料，我们可得到全球台站更均匀分布的台站资料。为了使用户充分受益，数据交换应是首先考虑的问题。     

与地壳活动有关的ULF地磁变化：RIKEN-NASDA项目概要和最新结果

尽管地震短临预报极其重要，并且经过了人们多年的努力，但它仍是目前未能解决的问题。近年来，与地震相关的电磁现象被认为是解决地震短临预报的有效途径之一。现在已经积累了大量的地震电磁前兆信号的震例，这些信号分布在很宽的频带范围(DC-VHF)内，其中ULF地磁变化是最有希望的地磁前兆之一。通过监测ULF地磁变化，有望实现地震短临预报。本文将阐述从ULF电磁信号中提取震磁异常变化的方法。     

TOXICITY OF TWO HERBICIDES 2,4 -D DIMETHYLAMINE AND BENSULFURON METHYL TO RICE FIELD CHIRONOMUS KIIENSIS (TOKUNAGA) ( DIPTERA: CHIRONOMIDAE)

1 INTRODUCTIONRice field is a unique man -made wetland envi-ronment where many varieties of aquatic insects oc-curred ( Ali, Ahmad, 1988; Yamazaki,et al,2001a; Che Salmah, Abu Hassan, 2002). Duringrice cultivation in Malaysia, herbicides are used in-tensi…     

藏西南纳木那尼峰地区第四纪以来的冰川演化

藏西南纳木那尼峰地区第四纪以来经历了多阶段的冰川演化,遗留了各个阶段不同类型的冰川堆积地貌和冰川侵蚀地貌。文章通过对各阶段冰积地貌的分布范围、特征的描述,并根据保存程度确定其相对地貌年龄,初步认为本地区第四纪以来倒数第3次冰期发育了规模最大的冰原冰川,倒数第2次冰期时冰原缩小并逐渐解体,末次冰期以来完全解体为山谷冰川。根据本地区槽谷的形态特征及冰川堆积物的分布,认为本地区末次间冰期前后有一次活跃的构造运动。