基于地形的县域生态系统服务价值分析

通过收集2007年和2017年绛县的DEM数据和遥感数据,经遥感解译和GIS重分类,将该区域高程划分为6个等级、地形坡度划分为5个等级、土地利用类型划分为7类,计算和探讨了2007—2017年间绛县各土地利用类型的生态系统服务价值和单项生态系统服务价值在地形梯度上的变化情况,并计算了生态系统服务价值动态度和敏感性指数。结果表明:2007—2017年间,绛县土地利用面积增加了9 596 hm~2,生态系统服务总价值增加了14 762.80万元;生态系统服务价值增加量最大的为林地,生态系统服务价值减少量最大的为耕地;林地在900～1 200 m地形梯度上有最大的生态系统服务价值增加量12 620.66万元,在13°～20°地形坡度梯度上有最大的生态系统服务价值增加量9 946.53万元;在各单项生态系统服务价值类型方面,气体调节生态系统服务价值增加量最大,废物处理生态系统服务价值减少量最大;建设用地的生态系统服务价值动态度和敏感性指数最大,林地对绛县的生态系统服务价值贡献最多。     

北京市水源保护林体系的基本格局与发展思路

本文论述了国内外水源保护林的研究现状,从北京市水源保护林规划区的林种、树种格局上看,水源保护林在各类土地面积和林种中的比例明显偏小,灌木林地、疏林地和宜林荒山仍占有较大的面积。树种资源单一,柞树面积最大,约占有林地总面积的36.2%,面积达5%以上的树种仅有5个。为此提出了多林种、多树种的发展思路,规划林种发展比例并在疏林地和宜林荒山发展栓皮栎、元宝枫、黄栌、白皮松、樟子松等树种。     

铝型材挤压模CAD/CAM系统及其关键技术的研究

此文介绍了铝型材挤压模CAD/CAM系统的构造方法和总体结构,以及其中关键问题的解决方法。作者开发的铝型材挤压模CAD/CAM系统(HECAD)可进行平面模和分流模的设计,能输出模具设计工程图纸及模孔线切割加工指令。     

UG在模具CAD/CAM中的应用

此文简述了我所模具CAD/CAM系统,重点叙述了我们在进行模具CAD/CAM技术应用、研究时对一些技术问题的处理,并列举了加工实例进行说明。为模具设计及制造提供了一种新的思路与方法,以加速模具技术的发展。     

Quantitative structure-property relationship of aromatic sulfur-containing carboxylates

IntroductionItiswidelyrecognizedthatthephysicochemicalprofileoforganicchemicalslargelydeterminestheirdistributionbetweenenvironmentalmedia .Fortheenvironmentalbehaviorsoforganiccontaminants,watersolubility(SW)andoctanol waterpartitioncoefficient(KOW)aretremendouslyimportant.Octanol waterpartitioncoefficienthasbeenwidelyrelatedtobiochemicaland orbiologicalactivityinquantitativestructure activityrelationships(QSARs) (Leo ,1 971 ) .Watersolubilitycorrespondstothedispersiontendencyandtothereca…     

土地利用的生态规划：以天津市中心区为例

本文旨在建立一套适宜的城市土地利用生态规划的原则与方法，分析天津市区各种土地利用类型的生态适宜性；帮助当地决策者制定具体的生态对策，以促进城市的发展，改善居民的生活质量；为决策得因工业和居住区要而引起的环境问题提供一条新途径。     

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.     

某生活污水处理站设计经验总结

介绍某生活污水处理站的工程设计和工艺流程,以及主要的构筑物及其设备;并对污水处理站在运行管理中出现的问题进行剖析,对设计出现的问题进行理论和实践分析,并进行整改;最后在实际运行的基础上,总结经验教训并对处理规模进行预测,以及对以后的同类型污水处理站的设计提出一些参考性的经验参数.