新形势下测绘保密工作的思考

在《中华人民共和国测绘成果管理规定》及其相关的管理规定中 ,对基础测绘成果保密等级的划分、调整和解密都作了详细的规定。但是在新形势下 ,现行保密法规的对象发生了变化 ,传统的保密管理方式已不适用 ,因此 ,应在保守国家核心机密的前提下 ,重新审定各种地理信息产品的密级 ,最大限度地扩大流通服务范围 ,使地理信息能更多更好地为国民经济建设服务     

Recent trends in vegetation dynamics in the African Sahel and their relationship to climate

Contrary to assertions of widespread irreversible desertification in the African Sahel, a recent increase in seasonal greenness over large areas of the Sahel has been observed, which has been interpreted as a recovery from the great Sahelian droughts. This research investigates temporal and spatial patterns of vegetation greenness and rainfall variability in the African Sahel and their interrelationships based on analyses of Normalized Difference Vegetation Index (NDVI) time series for the period 1982–2003 and gridded satellite rainfall estimates. While rainfall emerges as the dominant causative factor for the increase in vegetation greenness, there is evidence of another causative factor, hypothetically a human-induced change superimposed on the climate trend.     

Water supply potential and optimal exploitation capacity of karst aquifer systems

The management of groundwater flow systems in karst regions appears, at present, to be the most important procedure for solving water deficiency problems during periods of low rainfall. Faced with a lack of data for characterizing the water supply potential of karst aquifers, analyses of spring hydrographs may provide valuable indirect information regarding the structure of karst hydrogeological systems. To estimate the optimal exploitation capacities of karstic sources, a stochastic-conceptual approach was applied in case studies from the Serbian karst. Water supply potentials were initially evaluated on the basis of groundwater budgets. Further steps towards defining optimal “exploitable” regimes included analyses of storage changes in karst water reservoirs under natural conditions and calculation of the potential expansion of currently tapped sources. The results obtained through these analyses are a significant contribution to feasibility studies and aid in the avoidance of problems of overexploitation.     

洞庭湖流域水生态系统服务功能经济价值研究

以洞庭湖流域水生态系统为例,在明确河湖库塘生态系统服务功能内涵的基础上,运用生态学与生态经济学方法对洞庭湖流域各类水生态系统服务功能经济价值进行了评估。结果表明,全流域河湖库塘水生态系统服务功能总价值量为1106.19亿元,约占湖南省2004年GDP(5612.26亿元)的19.7%,其中,城镇和农村生活供水、工农业生产供水、水力发电、内陆航运等直接利用价值为415.698亿元;调洪、输沙、水资源贮存等间接利用价值为690.492亿元。可以认为,流域水生态系统服务功能对湖南省工农业生产的持续发展,维系生态环境健康和人民生命财产安全起到了不可替代的支撑和保障作用。     

Seismic rotational displacement of gravity walls by pseudo-dynamic method: Passive case

Prediction of the seismic rotational displacements of retaining wall under passive condition is an important aspect of design in earthquake prone region. In this paper, the pseudo-dynamic method is used to compute the rotational displacements of rigid retaining wall supporting cohesionless backfill under seismic loading for the passive earth pressure condition. The proposed method considers time, phase difference and effect of amplification in shear and primary waves propagating through both the backfill and the retaining wall. The influence of ground motion characteristics on rotational displacement of the wall is evaluated. Also the effects of variation of parameters like wall friction angle, soil friction angle, amplification factor, shear wave velocity, primary wave velocity, period of lateral shaking, horizontal and vertical seismic accelerations on the rotational displacements are studied. The rotational displacement of the wall increases substantially with increase in amplification of both shear and primary waves, time of input motion, period of lateral shaking and decreases with increase in soil friction angle, wall friction angle. The rotational displacements of the wall also increase when the effect of wall inertia is taken into account. Results are provided in graphical form.     

地震前兆数据的管理与服务

简要介绍了中国地震局全国地震前兆台网中心及其前兆数据来源和特点，重点分析了该中心的数据管理、数据服务及应用。全国地震前兆台网中心在剖析地震前兆数据的结构和总结其特点的基础上，选择了自行研制的基于双表数据结构的CAPOmen平台来管理和维护各种前兆数据，并枚举了该平台所具有的一些特点，前兆台网中心还运用Web和FTP等网络传输手段与用户及研究单位进行各种数据交换和共享，提供以CAPOmen 平台为后台数据库管理的基于浏览器的前兆数据查询、浏览、下载及其他服务等。并对地震前兆数据的管理提出几点建议。     

河南省汛期气候预测概念模型

在河南省6种雨型的基础上，分析了物理要素海温、季风、西太平洋副高及气候因子和河南省汛期降水的关系，给出了河南省汛期降水的气候预测概念模型。通过逻辑推理，可以具体预测雨型。     

The Character of Shear-wave Splitting in Marble in the Critical State of Rupture

This paper mainly observed and analyzed the character of shear-wave splitting in rock specimens while they were in the critical state of rupture. The rock specimens for study are made of Laizhou marble from Shandong, China. A series of records were obtained from two rock specimens when they were in the critical state of rupture. The result shows that, in the critical state just before rock rupture, there may be the phenomenon of rise and fall in the time delay of shear-wave splitting, even though the load was kept constant. That is to say, the time delay of shear-wave splitting may have a falling process before rock rupture.     

场对场预报模型及其对降水的预报试验

用经验正交函数对预报因子场和预报对象场分别进行分解，将正交展开的时间系数作为预报因子和预报对象，提出了一种场对场预报模型，该模型考虑了预报系统的时变性，并利用云南５月份的雨量资料进行了预报试验。结果表明，用这种模型作区域性降水预报有一定的优越性。     

影响CT球管寿命的非质量因素

影响ＣＴ球管寿命的非质量因素是指对其使用寿命的长短产生影响的因素。笔者通过对多年工作实践的总结，从操作技术、维修保养等方面探讨诸因素对ＣＴ球管寿命的影响。