珠江口滨海湿地退化现状、原因及保护对策

2007年和2008年秋季对珠江口滨海湿地进行了环境现状综合调查,结果表明,珠江口滨海湿地退化主要表现在4个方面:天然湿地面积减少、湿地生产力不断下降、湿地环境状况持续恶化和湿地景观破碎化。珠江口滨海湿地退化的原因主要为滩涂开发与围填海、污染物排放、养殖污染、海平面上升、过度捕捞、海砂开采和港口码头建设以及水土资源开发等因素。滨海湿地保护与利用对策主要有:制定有关滨海湿地保护的法律法规和湿地保护与利用规划;加强人才队伍建设和滨海湿地有关技术研究;建立滨海湿地动态监测体系;加大滨海湿地保护区建设的力度;加强宣传和教育。     

Extending self-organizing maps for supervised classification of remotely sensed data

An extended self-organizing map for supervised classification is proposed in this paper. Unlike other traditional SOMs, the model has an input layer, a Kohonen layer, and an output layer. The number of neurons in the input layer depends on the dimensionality of input patterns. The number of neurons in the output layer equals the number of the desired classes. The number of neurons in the Kohonen layer may be a few to several thousands, which depends on the complexity of classification problems and the classification precision. Each training sample is expressed by a pair of vectors ： an input vector and a class codebook vector. When a training sample is input into the model, Kohonen＇s competitive learning rule is applied to selecting the winning neuron from the Kohouen layer and the weight coefficients connecting all the neurons in the input layer with both the winning neuron and its neighbors in the Kohonen layer are modified to be closer to the input vector, and those connecting all the neurons around the winning neuron within a certain diameter in the Kohonen layer with all the neurons in the output layer are adjusted to be closer to the class codebook vector. If the number of training sam- ples is sufficiently large and the learning epochs iterate enough times, the model will be able to serve as a supervised classifier. The model has been tentatively applied to the supervised classification of multispectral remotely sensed data. The author compared the performances of the extended SOM and BPN in remotely sensed data classification. The investigation manifests that the extended SOM is feasible for supervised classification.     

Causes of rockfalls in Al-Huwayshah area,Yemen

According to topography of Yemen,most areas and villages are located at obligated crest,toe of mountain and under cliffs.Therefore Al-Huwayshah consisting of Tawilah sandstone group is characterized by steep slope reach to 90° in some areas.This area is affected by strong tectonic movements and faults that occurred during the geological epochs.This effect enhances to find out fractures and joints as well as the rocks become brittle and ready to slide depending on the position of area.And there are some frac...     

Characteristics and evolution of lacustrine turbidite of Chang-7 Member of Yanchang Formation in northern Shaanxi

Lacustrine turbidite of Chang-7 Member in the studied area consists of sihstone and fine sandstone with respect to grain size, which is feldspathic lithie sandstone, syrosem arkose and arkose with respect to mineral constitution affected by provenance. There are such apparent signatures as lithology, sedimentary structure, sedimentary sequence and well logs, to recognize turbidite. During the paleogeographic evolution of Chang-7 Member, lake basin and deep lake are both at their maximum extent during Chang-73 stage, resulting in the deposition of Zhangjiatan shale with widespread extent and of turbidite with fragmental-like. Deep lake line is gradually moving toward lake center and turbidite sand bodies are gradually turning better with better lateral continuity, connectivity and more thickness, from stages of Chang-73, Chang-72 and Chang-7t, which can be favorable reservoir in deep-water.     

上海地区深部构造特征和地震活动趋势探讨

本文介绍由重磁资料计算上海地区居里面、莫霍面、均衡重力异常及地幔流应力场的方法和成果,并在对成果初步分析的基础上,探讨了深部地质构造特征及其与地震活动趋势的关系,其中着重讨论了居里面及其与地震活动的关系。文章最后提出了对上海地区地震活动趋势的几点认识。     

Geological - Geophysical - Geochemical Exploration Models of Copper - Iron Deposits in Southeastern Hubei

This paper discusses geological-geophysical-geochemical models of such typical deposits as the Tieshan-type Fe-Cu deposit, the Tonglushan-type Cu-Fe deposit, the Yehuaxiang-type Cu deposit, the Jiguanzui-type Cu-Au deposit, and the Tongshankou-type Cu (Mo) deposit. The models were established based on practical data of the polymetallic deposits dominated by copper ore in southeastern Hubei. These models, which are graphically illustrated in the paper, systematically summarize the metallogenic geological conditions and the geophysical-geochemical characteristics of copper deposits in this area. The models are of practical significance for studying copper deposits, predicting mineral resources, choosing exploration methods, and searching for ore deposits based on existing ones in the study area.     

第二代航磁黄沙坪异常的分解及其矿产新空间

本文采用同时具有识別、分解、解释异常三重作用的三元解释法■,在黄沙坪异常负值区有效地提取了由未知的深源磁性体引起的剩余异常。该异常与已知的中、浅源磁性体分处于极为类同的成矿地质背景中。后者与隐伏岩体、铅锌多金属盲矿体之间有着密切的成生联系。这为前者间接找矿提供了有力的依据。定量解释结果中,两者间的磁矩等效关系,论证了已知矿床西侧深部空间里,仍存在找到又一个大型矿床的前景。     

A NUMERICAL MODEL FOR SEDIMENTATION IN FENHE RESERVOIR AND THE ADJOINING REACHES

In this paper, a numerical model for sedimentation in Fenhe Reservoir and the adjoining reaches has been presented on the basis of the theory of non-equilibrium sediment transport. The model is calibrated by using a part of the sediment data collected for Fenhe Reservoir and checked by simulating the remaining data. Moreover, the method of optimization in nonlinear programming has been applied to determine the basic parameters of the model applying a concept of fuzzy mathematics to formulate the objective functions. The computed amounts of reservoir deposition and channel deformation arc found to be substantially in agreement with the values observed.     

钇易解石族的端员—钛钇易解石的发现

本矿物为新发现的钇易解石族的端员矿物－钛钇易解石，产于江西省龙南县足洞燕山期中粒白云母花岗岩及其风化壳中。矿物属斜方晶系，常呈板状或短柱状，为天然晶质体，浅黄色，粒度为０．０７５ｍｍ，硬度４．７，比重４．７３，二轴正晶，Ｎｇ＝２．２４８，Ｎｍ＝２．２１２，Ｎｐ＝２．１９４，Ｎｇ－Ｎｐ＝０．０５４，２Ｖ＝７０°。空间群为Ｄ＾１６２ｈ－Ｐｍｎｂ，ａ０＝０．７５０ｎｍ，ｂ０＝１．０９２ｎｍ，Ｃ０＝０．５     

沉积岩中蒙脱石-伊利石混层矿物的SEM/EDAX分析

本文利用扫描电子显微镜与X射线能量色散分析联合法,对沉积岩中蒙脱石-伊利石混层矿物进行系统微区成分分析,求出混合层中伊利石的百分含量。