Vegetation patterns and nature reserve construction in an extremely-arid desert in Anxi,NW China's Gansu Province

Anxi County is located in the northwestern part of the Hexi Corridor in gansu Province and has the sole national level nature reserve of extremely-arid desert in China.Phytosociological methods (Braun-Blanquet,1964) are used to classify plant community types in this area.Eleven are disting uished,including six of deserts,four of oases and one transitional type between deserts and oases.Direct gradient analysis (DCA) is employed to correlate the distribution of plant communities to physiogeographic conditions.This study makes clear that water is the most important ecological factor for the distribution of plant species and communities in this area.The effects of water have been demonstrated in different ways.A vegetation gradient from lower altitude to higher altitude in the southern part of the reserve is driven by a precipitation gradient.The effects of the depth of ground water table contribute to the differentiation of vegetation from desert to oasis in the flat area.In a finer scale,the washed gullies have obviously higher species richness and also higher vegetation cover than the surround gobi surfaces,possibly caused by the effects of floods.The vegetation patterns demonstrate that the area of Anxi County is a complete landscape unit.The range of the current nature reserve is not large enough for the purpose of conserving the unique biodiversity in this area.     

循环经济在煤矿生产中的实施和发展前景

循环经济是2l世纪可持续发展的战略选择,煤矿生产发展和实施循环经济模式是煤炭行业经济结构改革的重要内容。通过对煤矿生产过程中发展循环经济的论述。探讨了煤矿生产建立“煤电建材联营”为产业链的循环经济发展模式,提出了煤矿生产实施循环经济的措施。     

周边式二次沉淀池流态的计算模拟研究

通过计算模拟二沉池流态,解决了二沉池流态测定的难题,该模拟方法速度快、精度高、不需要实型池.通过对实际池的计算发现,周边式二沉池上溢流集中在靠池周边的区域,以垂直向上的流线为主,池中心上部存在着较大的水流死区,由此解释了该类型池澄清能力小的原因.     

The effects of land use and its patterns on soil properties in a small catchment of the Loess Plateau

Due to relatively strong human activities in the hilly area of Loess Plateau,the natural vegetation has been destroyed,and landscape pattern based on agricultural land matrix was land use mosaic composing of shrub land,grassland,woolland and orchard.This pattern has an important effect on soil moisture and soil nutrients.The Danangou catchment,a typical small catchment,was selected to study the effects of land use and its patterns on soil moisture and nutrients in this paper.The results are as follows:The comparisons of soil moisture among seven land uses for wet year and dry year were performed:(1)the average of soil moisture content for whole catchment was 12.11% in wet year,while it was 9.37% in dry year;(2)soil moisture among seven land uses was significantly different in dry year,but not in wet year;(3) form wet year to dry year,the profile type of soil moisture changed from decreasing type to fluctuation-type and from fluctuant type to increasing type;(4)the increasing trend in soil moisture from the top to foot of hillslope occurred in simple land use along slope,while complicated distribution of soil moisture was observed in multiple land uses along slope.The relationships between soil nutrients and land uses and landscape positions were analysed:(1)five nutrient contents of soil organic matter(SOM),total N(TN),available N(AN),total P(TP) and available P(AP) in hilly area were lower than that in other areas.SOM content was less than 1%,TN content less than 0.07%,and TP fallow land and cropland,and higher level in soil fertility was found in crop-fruit intercropping land among croplands;(3)soil nutrient distribution and responses to landscape positions were variable depending on slope and the location of land use types.     

地理变异系数法和Fisher最优分割法在环境空气监测优化布点中的应用

在环境空气监测点位优化中,为反映优化后点位的整体代表性,需要在允许的测定误差内以最少的测点反映区域内较长时期的整体污染水平、污染分布状况和污染趋势.本文以博山城区为例,利用地理变异系数法和Fisher最优分割法对所布设点位进行数理统计.该方法使用简便,分级自然,避免了诸多人为因素的影响,同时,优选结果具有较强的整体代表性.     

我国不同类型地下工程中的氡水平

为了解我国地下工程内氡的浓度水平及其可能对人体产生的危害,采用核固体径迹法,在不同季节对全国23个城市的234个地下工程测点的氡浓度进行了测量。根据工程的建筑类型及用途的不同,将所有被测工程分为坑道、干道(包括掘进式地道工程)、地下室(高层建筑地下室和掘开式工程)和停车场四类,各类工程的氡浓度平均值分别为327、619、96.9、59.1 Bq.m-3。对于不同山体岩性的坑道,氡浓度值由高到低的顺序是花岗岩>凝灰岩>石英砂岩>石灰岩>安山玢岩。比较各类工程不同季节的氡浓度,得出,停车场氡浓度季节变化不大,其它三类工程都有氡浓度夏季明显高于冬季的特点,而且通风差的未使用的坑道和干道比使用中的同类工程具有相对高的氡浓度夏/冬比值。     

我国环境管理模式法律问题探讨

通过对市场体制下政府在环境管理中职能及我国环境管理现状分析,借鉴国外发达国家环境管理实践经验,认为现代市场经济国家主要通过环境规划的指引作用、环境政策工具及环保制度的推动作用、以及环境法规的扶持规范作用,共同推动环境管理实践.     

碱性闪石类质同象的向量空间

用结构分析法确定闪石中阳离子的占位已为人们所熟知，本文采用44个碱性闪石的化学分析数据，通过逐步回归分析，从统计学的角度来分析碱性闪石各晶位中阳离子占位率之间的相关性，从而进一步探讨其类质同象的规律，分析表明：碱性问石中作为独立变量的阳离子并非如通常认为的多而杂，如果把碱性闪石类质同象看成一个随机线性向量，则其空间的维数很可能小于10，上述理论计算同时还表明：1．有可能直接用化学分析结果按概率方法对闪石进行定名；2.有可能选择X射线粉末图大于10条特征峰的强度作统计分析来估算闪石中阳离子的占位率。     

相对灰色关联度在城市污水处理工艺优选中的应用

通过对城市污水处理工艺评价指标的定量化处理，并根据奖优罚劣的原则对初始指标集进行[-1，1]区间线性规范化处理，确定理想最优方案（A^＊）和理想最劣方案（A-），以此计算出各待选方案与它们的相关系数（ζ）。采用变异系数法计算各指标权重（ω），并计算各候选方案相对最优方案的灰色关联度，进而确定最佳方案。     

海岸生态交错带景观空间格局及其受开发建设的影响分析——-以海南万泉河口博鳌地区为例

以海南万泉河口博鳌镇(亚洲论坛会址)为研究区域,分析了海岸生态交错带景观生态基本特点,选取景观多样性、优势度、景观破碎度、景观分离度及生态风险指数作为评价指标,通过对景观空间格局及其变化的分析,讨论了该区域开发建设对景观空间格局的影响。研究表明:开发建设的强弱是导致博鳌区域景观格局变化的驱动力,并提出了相应的景观生态建设对策。