Silicon limitation on primary production and its destiny in Jiaozhou Bay, China——Ⅳ：Study on cross-bay transect from estuary to ocean

The authors analyzed the data collected in the Ecological Station Jiaozhou Bay from May 1991 to November 1994, including 12 seasonal investigations, to determine the characteristics, dynamic cycles and variation trends of the silicate in the bay. The results indicated that the rivers around Jiaozhou Bay provided abundant supply of silicate to the bay. The silicate concentration there depended on river flow variation. The horizontal variation of silicate concentration on the transect showed that the silicate concentration decreased with distance from shorelines. The vertical variation of it showed that silicate sank and deposited on the sea bottom by phytoplankton uptake and death, and zooplankton excretion. In this way, silicon would endlessly be transferred from terrestrial sources to the sea bottom. The silicon took up by phytoplankton and by other biogeochemical processes led to insufficient silicon supply for phytoplankton growth. In this paper, a 2D dynamic model of river flow versus silicate concentration was established by which silicate concentrations of 0.028–0.062 μmol/L in seawater was yielded by inputting certain seasonal unit river flows (m³/s), or in other words, the silicate supply rate; and when the unit river flow was set to zero, meaning no river input, the silicate concentrations were between 0.05–0.69 μmol/L in the bay. In terms of the silicate supply rate, Jiaozhou Bay was divided into three parts. The division shows a given river flow could generate several different silicon levels in corresponding regions, so as to the silicon-limitation levels to the phytoplankton in these regions. Another dynamic model of river flow versus primary production was set up by which the phytoplankton primary production of 5.21–15.55 (mgC/m²·d)/(m³/s) were obtained in our case at unit river flow values via silicate concentration or primary production conversion rate. Similarly, the values of primary production of 121.98–195.33 (mgC/m²·d) were achieved at zero unit river flow condition. A primary production conversion rate reflects the sensitivity to silicon depletion so as to different phytoplankton primary production and silicon requirements by different phytoplankton assemblages in different marine areas. In addition, the authors differentiated two equations (Eqs. 1 and 2) in the models to obtain the river flow variation that determines the silicate concentration variation, and in turn, the variation of primary production. These results proved further that nutrient silicon is a limiting factor for phytoplankton growth. This study was funded by NSFC (No. 40036010), and the Director's Fund of the Beihai Sea Monitoring Center, the State Oceanic Administration.     

基于Chandra的活动星系核观测

活动星系核（AGN）是宇宙中最奇特的天体之一。它是真正意义上的全波天体，其中X射线波段的发射功率占到全波段功率的50％左右。AGN的X射线辐射研究涉及天体物理中的最基本问题，例如能量产生、辐射机制和宇宙论等，而Chandra X射线卫星的高分辨率图像和光谱对这一研究有着重要作用。以Chandra卫星的部分观测结果为例，简要介绍了几类不同类型AGN的X射线辐射研究进展：（1）宽吸收线类星体APM08279＋5255（z=3．91）的X射线谱分析，以及高红移类星体的观测概况；（2）Seyfert星系NGC 4151延展X射线发射问题的解决，及NGC 1068X射线辐射与光学波段的高激发态发射线（[OⅢ]λ5007）有很强相关性的发现；（3）6个BLLac天体样本的X射线环境分析；（4）射电星系X射线喷流的观测等。     

调频式电涡传感器微机实现的探讨

分析了分频和ＣＴＣ计数采样中误读数的原因和解决方法，并利用微机软件实现非线性校正。此传感器用于位移测量系统中，具有０．０１ｍｍ的分辨率及优于１％的精度，可在－２０～６０℃温度范围内工作。     

沉积物粒度分析在厦门市第四纪环境研究和地层划分对比中的应用

采用MS2000型激光粒度分析仪进行测试，利用计算机粒度分析软件对数据进行整理和计算，绘制出样品的频率曲线、概率累积曲线以及粒度众数位值曲线等图件并进行沉积环境分析。厦门地区第四纪环境演化经历了中更新世同安组(含泥中粗砂、含泥细中砂、砂为主)海积一冲积一更新统上部龙海组(含泥粗中砂、含泥细中砂、含泥粗砂、粗砂、细中砂、含细砾中粗砂、中细砂等)冲积一洪冲积一更新世上部东山组(砂、砂砾、含泥中粗砂、粗砂、泥质中细砂、细砂、中粗砂等)冲洪积及部分海积(粉砂、细粉砂、含碳质泥、粘土、淤泥质粘土、粉砂质粘土等)一全新世长乐组(粉砂，淤泥质粘土、粉砂质粘土、碳质粘土、含砂淤泥质粘土，粉砂质亚粘土、粉细砂亚粘土等)海湾沉积。在解释环境变化的同时，说明粒度变化曲线在一定程度上可以作为地层划分的依据之一，并以此对研究区地层进行了详细划分。     

Galileo系统及其在中国的应用

较详细地介绍了Galileo系统的全面体系结构、频率设计、服务内容及其广泛的应用范围，指出了它与GPS系统相比的优点，并对开发和增强Galileo系统在我国多层次、全方位的应用提出了建议。     

区域GPS网实时计算可降水量的若干问题

目前地基GPS气象学测得的可降水量 (PWV )精度好于 2mm ,但在利用区域GPS网实时计算每个测站上空的PWV时 ,要涉及到很多常规GPS资料处理时所忽略的问题 ,如需考虑数据处理软件和计算方式的选择、站坐标的确定和约束、轨道的使用方法、网外辅助站最佳数量的确定、海潮对实时计算PWV的影响以及实时应用于气象服务时的端部效应等问题。利用上海GPS综合应用网获取的 2 0 0 2年 6、7月份长江三角洲地区入梅前后的数据 ,分析了利用区域性的GPS网实时计算高精度的PWV时要解决的各种问题 ,探讨了其数据处理方案     

基于GPS实现测频等功能的虚拟仪器的研制

设计和研制了一种适用于大专院校示范教学实验的虚拟仪器。该虚拟仪器以GPS接收模块输出的1PPS(秒脉冲)信号为基准,测量无源石英晶体振荡器频率,同时利用GPS信号实现了仪器的时间同步与测距功能。从硬件和软件两方面描述了该虚拟仪器的构成及设计方法,主要介绍和讨论基于GPS和虚拟仪器技术实现多功能测量的途径。     

青藏高原及邻近区域的S波三维速度结构

本文收集了WWSSN台网和我国台网中13个地震台站的长周期地震记录,用140条10-90s瑞利波频散曲线和作者提出的Tarantola-Backus面波频散层析成象方法,作了青藏高原及邻区的速度反演,得出该地区岩石层速度结构的三维图象.结果表明,1.在10-110km深度范围内,速度结构出现与大地构造特征相关的分区性,显示出四个构造单元:青藏块体、柴达木-巴颜喀拉-三江块体、塔里木块体和印度块体.2.高原内部,深度为10-70km内速度较低,莫霍界面呈不对称盆形分布,藏北那曲附近地壳厚度超过70km,高原边缘壳厚为45-50km,90-110km为高速异常,表明高原内部存在上地幔盖层.3.高原北部的班公湖断裂和东部的三江断裂系是该区重要的分界线,是岩石层结构存在明显差异的重要接触部位,可能是冈瓦纳古陆与欧亚古陆的缝合带.4.柴达木-巴颜喀拉-三江块体内部速度分布不均匀,地壳厚度由北向南从45km加深到60km;在深度90-110km存在一低速层.5.塔里木地块内速度随深度均匀增加,从地壳到上地幔110km内没有发现低速层.地壳厚度约50km.