Modelling the Venice Lagoon

In this paper, an overview is given on the modelling activities at the National Research Council in Venice (ISDGM-CNR) concerning the Venice Lagoon. A short history of former modelling efforts is given. A finite element hydrodynamic model is presented that has been created especially for the Venice Lagoon. This model has been applied to various situations. Residual currents have been computed for one year. A specific storm surge event has been simulated with spatially varying real winds. A transport diffusion model has been applied to model the impact of a treatment plant on the central lagoon. And a sub-basin has been modeled with a high resolution grid.     

Soil Destruction in Norway

In the coastal regions of western and northern Norway where there is little forest, peat is the most important fuel, as it has been for centuries. Because of this the sources of good peat have been reduced greatly in many districts. The peat in the coastal districts rests often directly on rock without loam, sand or gravel between the rock and the layer of organic material above. If the peat is removed, the land will be transformed into ponds or swamps. In the course of time great areas suited for cultivation have been destroyed in this way.

When the peat has been excavated, then the turf on more or less dry ground is utilized for fuel, i. e. grass turf and heather turf. In this way the surface humus layer is removed and the underlying mineral soil exposed to further erosion. The mineral layer that is left behind is usually too shallow or too coarse-grained to yield any production, and the posibilities for further use are diminishing. On the other hand, the ground might have been used as grazing land or for forest if the upper layer had been allowed to remain.     

黄河下游游荡性河道小水致灾研究

20世纪80年代中期以来,黄河下游游荡性河道的洪水灾害是在下游水量明显减少、洪峰流量也不断减小的情况下发生的。即使是水量比较小的普通洪水,也能造成下游滩区大面积受淹、控导工程决口、桥梁被冲毁、房屋倒塌等严重灾害。小水致灾的形成机理主要是:河道游荡,引发“横河、斜河”;小水淤积,河床抬高,行洪能力下降;人与河床争地,造成滩区阻塞。     

Kirchhoff synthetics for seismic reflections and diving waves in two dimensions and application to the D" layer

The Kirchhoff-Helmholtz (KH) integration has been used to model the reflected and the diving waves from an interface with a positive velocity gradient. The modelling is carried out for a spherical boundary and for a sinusoidal topography with a long-scale wavelength.
An artefact, which is a major problem in modelling the seismic response using the KH integration, has been reduced by introducing a Hilbert transform sign manipulation. Cleaner synthetic seismograms with correct amplitudes have been produced by this method. A discretization in larger surface elements has been made possible by introducing a smoothing factor that suppresses the noise that normally follows the constructed signal if a large element size is taken.     

基于集群理论的产业规划模式探析

传统产业规划在信息网络时代正受到诸多挑战,地方化、信息化正成为地区产业发展的重要驱动力量,在此思路上,本文试图构建一种新型的产业规划模式——集群理论下的产业规划模式。文章首先分析了传统产业规划的概念、基础理论及其存在问题,在此基础上引入了集群理论并梳理了其理论要点,同时借鉴国外集群创导理论和一些具体规划范式构建了基于集群理论的产业规划的一般模式,并对该模式实施的误区及其与传统产业规划的区别联系进行了分析,最后提出了模式实施的相关保障措施。     

中国湖泊与环境演变研究的回顾与展望

我国70～80年代中期,湖泊沉积研究受油田开发的带动而得以兴起;80年代中期之后,科研力量不断壮大,研究的内容侧重气候变化,研究区域不断扩大,方法不断完善,测年手段更趋精确;近几年来又特别注重研究云贵高原和青藏高原的湖泊,强化短时间尺度研究,注重人为因素对湖泊沉积环境的影响。今后该领域研究应注意加强环境指标的综合运用与定量化研究,强化分析环境演变中人为因素的影响,尽快建立中国第四纪湖泊数据库,积极开展极地地区湖泊的相关研究。     

动态广义表空间索引方法

提出了一种新的动态空间索引结构X-Lists,设计实现了X-Lists的动态插入、动态删除、查找等算法,并进行了算法实验。X-Lists是一种支持高维点查询和区域查询的广义表,实验表明,X-Lists在索引构建与区域查找方面性能明显优于现有R-Tree及其改进索引结构。     

THE PERFORMANCE OF LEAST SQUARES AND ROBUST REGRESSION IN THE CALIBRATION OF ANALYTICAL METHODS UNDER NON-NORMAL NOISE DISTRIBUTIONS

By means of Monte Carlo simulations a comparison has been made between ordinary least squaresregression and robust regression. The robust regression procedure is based on the Huber estimate and iscomputed by means of the iteratively reweighted least squares algorithm. The performance of bothprocedures has been evaluated for estimation of the parameters of a calibration function and fordetermination of the concentration of unknown samples. The influence of the distributionalcharacteristics skewness and kurtosis has been studied, and the number of measurements used forconstructing the calibration curve has also been taken into account, Under certain conditions robustregression offers an advantage over least squares regression.     

Rb2CO3-CH3CH2OH-H2O三元体系20°C相平衡的研究

研究了Rb2 CO3-CH3CH2 OH -H2 O体系在 2 0°C下的相平衡 ,绘制了相应的溶度图。发现Rb2 CO3·2 .5H2 O的新物相 ,与以往报道的结果不一致     

基于遥感与GIS的黄土丘陵区生态监测系统研究——以定西地区4县为例

基于遥感和GIS技术建立的甘肃中部黄土丘陵重点地区生态环境监测系统的初步监测结果表明,近10a来定西4县黄土丘陵区土地利用/土地覆盖变化显著。其中:增加最为显著的是菜地和果园,分别增加了275%和164%,说明试验区农业产业结构有较大的调整,即从单一的粮食生产转为与经济作物相结合的模式;减少最为显著的是河流和宜林宜草荒地,分别减少了68%、63%和67%,说明该地区对未利用土地的开发程度较大;该地区多年来推行水土保持和退耕还林工作,所以混交林和防护林增加的幅度较大,分别增加了43%和46%;该地区的连续建筑用地、分散建筑用地和交通用地都有较大幅度的增加,分别增加了34%、13%和21%,说明该地区经济的迅速发展和城市化的趋势。遥感与GIS为生态监测系统的建立与应用提供了丰富的数据源和强大的数据处理手段。     

榆林蟒坑滩的自然资源合理利用及沙漠化土地整治意见

本文对榆林地区沙化的一般规律进行了叙述,提出当地现代沙漠化的主要表现形式是固定和半固定沙丘的活化;提出了恢复沙地植被和生产力的设想.对滩地进行了成因划分,对湖沼洼地型滩地的生产条件作了重点分析,初步计算了蟒坑滩的地下水资源,提出为了改变滩地沼泽土"冷板田"土壤水分潴积的状况,应当充分利用滩区丰富的地下水,井灌井排。对蟒坑沙漠化土地的治理和滩地的合理利用也提出了比较切合实际的意见,可供生产部门参考。     

广州古城的湿地及其功能

历经2000多年,广州老城区的湿地环境变迁显著,广州珠江河道缩窄近9/10,不少古河涌今已改建成暗渠,面积广大的古湖泊及沼泽均已湮没.湿地在广州城市发展史上起着重要的作用,河涌担负着城市主要的交通运输及排水防涝功能,并引导着城市的发展与布局;各类湿地为城市提供了拓展空间和丰富的农产品;湿地还可以调节生态环境,美化城市景观,甚至为广州地方文化打上"水"的烙印.这一切对当今城市建设有着重要的启示.     

采空沉陷湿地形成动力过程的初步研究

因采空、沉陷和积水所形成的湿地是采矿沉陷区扰动了区域性地表水和地下水循环而产生了季节性或永久性积水而形成的一种湿地类型。从采空沉陷湿地形成的主要动力过程入手,研究其形成原因,明确其主要湿地特征。结果表明,采空积水沉陷地是在人类对地下矿层开采后,上覆岩层发生弯曲变形、断裂、位移,导致地面塌陷下沉,形成比采矿范围大得多的负地貌(低洼地);同时原有地表水系统因地表沉陷被破坏,使采矿沉陷区演变为局部汇水区,导致季节性或永久性积水;最终使其出现了沼泽化水生生态系统等特征,形成了一种新型人工湿地。     

云南松根系对土壤牵引效应测试系统的设计与实现

目前在野外对云南松根系与土壤的机械效庆的研究，由于测试研究受多种因数的影响，开展研究困难较大，研究精度也受到一定程度的影响，这对较深入的描述根系与土壤相互作用的机械效应带来一定的困难。本文基于这一实际，设计了能在室内和野外进行实时测试分析的测试系统，并配套了支持PCMCIA插槽的DAQP－12型模数转换（A／D）卡，以及直流电供电的QT－300型调理装置。结合所配套的硬件，利用Visual C在Windows95/98平台编写了软件，经过实际试验测试，系统各项性能能够满足云南松根系对土壤的机械效应研究的测试分析要求。     

中国荒漠化病因诊断

荒漠化研究和治理工作在中国已有多年,提出的治理措施与发表的研究论文硕果累累。但时至今日,荒漠化危害不仅依在,而且危害仍在逐年加剧,呈现这种局面的主要原因在于虽然对荒漠化的物理、生物机理有较透彻的认识,但对其社会机理还认识不够。社会管理者的科学求实态度、管理系统的自我调节功能、运转效率、协调程度以及受监督机制等深刻影响着一地区荒漠化的走势与治理结果。正在进行的西部大开发使中国荒漠化发展处于整体加速或减速的十字路口,一个好的环境结局将取决于干旱区社会管理者们科学素质的提高,思维决策模式与管理体制的革新。     

地理案例推理及其应

由于案例推理接近于人类认识、解决问题最原始的思维方式，具有在无法获取机理模型、确定规则或统计模型时，采用简单的历史相似性实现问题的定量求解和预测的特点，成为当前人工智能中备受关注的领域。在讨论案例推理方法发展的基础上，探讨应用案例推理进行地学问题求解的具体方法。从地学数据分析的角度提出了地理案例推理，并结合地理案例的特点，具体讨论了地理案例的表达模式和推理模型，最后结合东海中心渔场预报的实际工作，给出这种方法的具体应用实例。     

乌梁素海湿地环境演变

The environment evolution of Wuliangsuhai wetland since 1986 is analyzed based on the remote sensing principle. The total water area of Wuliangsuhai lake has been increased during the past 17 years. The open water area had an increasing trend before 1987, and the trend was decreasing up to 1996, then the trend has increased again since 2000; the variation of the water area with dense aquatic weed is basically contradictory to the variation of open water area. The natural reed area had been decreased before 1987, and then it has been increased. The areas of shallow water and swamp have been slightly increased, in fact, the variations are quite steady. The artificial reed area has been increased since the reed plantation was started in 1988. The relationships of the water environment, the climate, hydrology and different types of areas are discussed, and then the technological measures for sustainable development and utilization of Wuliangsuhai lake water environment are proposed.     

Automatic classification of dome instabilities based on Doppler radar measurements at Merapi volcano, Indonesia: Part I

Monitoring lava dome instabilities is crucial to efficiently monitor active dome building volcanoes. The Doppler radar technique provides a unique opportunity to gather information about the number of instability events occurring at the growing dome and about the dynamic processes that take place during different types of instabilities. So far, three different kinds of processes have been identified: sliding material, gravitational break-offs and explosive outbursts. In addition, Doppler radars provide rain measurements, which can be used to investigate possible correlations between rainfall and dome activity. Two radar systems have been installed at Merapi volcano in October 2001 and January 2005 to continuously monitor dome instabilities. Due to the large number of instability events that occur during times of high activity, manual processing and analysis of instability events is not practical for monitoring purposes. Therefore, an automatic classification system has been developed, which is capable of identifying different kinds of instabilities as well as rainfall. Two different kinds of classifier models have been applied: (1) neural network and (2) K-nearest-neighbour classifier model. Both classify Doppler spectra according to the underlying dynamic process, that is, rain, sliding material, gravitational break-off or explosive outburst. The classifiers are able to identify disturbances, which have no physical source, but are merely artefacts from the radar device itself. Because radar events are sequences of Doppler spectra, a rule set has been defined, which finally determines the event class. All classifiers have been trained and tested on independent data sets to estimate the classification performance. The overall classification rate is about 90 per cent. Discrimination of instabilities and non-volcanic events reaches about 98 per cent accuracy.     

Additional evidence of pre-Silurian high-pressure metamorphic rocks in Spitsbergen

It has been previously suggested that the high-pressure metamorphic rock complex of Motalafjclla, central-western Spitsbergen, is older than Lower Silurian. An unconformity has been discovered at the base of a limestone which contains fossils similar to those reported as Lower Silurian from the same massif. This proves that the high-pressure metamorphics represent an older rock complex. The unconformity surface is inverted in the area, and large recumbent folds involving the Silurian Bulltinden Formation have been mapped. These folds are considered to be pre-Carboniferous.     

Frost heaving in ballast railway tracks

Frost heaving is a well-known phenomenon in cold regions, which may occur in wet clayey grounds during winter. Railway track upheaval occurring in cold regions during the winter is generally understood as frost heaving in the subgrade layer. However, it has been confirmed that upheaval due to frost heaving sometimes occurs in the ballast layer. This understanding has been observed in active railways in northern Japan. The samples collected from ballast and subgrade layers have been examined for frost heave susceptibilities and confirmed that ballast layers which contain fines may heave.