基于多元主体协同的县域耕地质量调控模式与整治时序分区

基于耕地利用与保护过程中多元主体协同的综合视角构建耕地质量调控模式,探索耕地质量整治时序分区及其具体应用模式,对合理有序地开展耕地资源整治与建设具有重要意义。该研究以华北集约化农区曲周县为研究区,在耕地质量评价的基础上,运用生态位障碍因子诊断模型识别耕地质量障碍因子,并结合耕地质量建设主体动力特征,从主体和客体协同视角构建耕地质量调控模式,进而基于耕地质量空间分布特征划分耕地质量整治分区,探索不同分区耕地质量调控模式的具体应用及其整治时序。结果表明:1)曲周县耕地质量以高等和中等为主,共占耕地总面积的77.42%,平均等级为2.54,总体处于高等质量和中等质量之间,但耕地质量局部呈现显著的正向集聚性;2)曲周县耕地质量各个指标不同障碍度等级的面积特征具有显著的差异性,耕地质量的主要障碍因子为有机质含量、地下水埋深、灌溉保证率、土壤阳离子交换量、全氮、有效磷和土体构型;3)基于政府、农户、村集体、企业、高校等不同主体建设动力,以耕地质量主要障碍因子整治为基本导向,从主导、核心、参与、指导、纽带等角度分析政府、农户、企业、高校、村集体等主体在生长条件、肥力水平、生产条件、水盐状况等不同维度的作用,从调控维度、调控指标、调控措施和调控主体等层面综合构建曲周县耕地质量总体调控模式;4)曲周县耕地质量可划分为优先建设区、重点建设区、潜在建设区和一般建设区四个整治分区,提出了耕地质量调控模式在不同整治分区的具体应用,制定了优先区近期建设、重点区中期建设、潜在区远期建设和一般区长期建设的耕地质量整治时序。该研究基于多元主体协同视角构建县域尺度耕地质量调控模式和识别耕地质量整治时序,可为市级和省级等不同尺度构建耕地质量调控模式与制定耕地质量整治时序提供基础依据。

基于农户意愿分析的农村居民点整理时序分区

农村居民点整理是优化居民点空间布局、改善农村环境及实现耕地占补平衡的重要手段,开展区域农村居民点整理时序研究,对农居点整理具有重要的指导意义。以南京市江北新区桥林和星甸街道为例,在农户意愿实地调研的基础上,结合居民点整理潜力,从整理迫切性、整理能力等角度选取关键指标,构建了农居点整理时序指标评价体系。基于评价结果,对研究区进行村域尺度的农村居民点整理时序分区。结果表明:(1)桥林和星甸街道可整理的理论潜力2 594.02hm^2,整理潜力较大,且各村整理潜力存在显著的差异;(2)对农户意愿影响较显著的因素有:补偿满意度、家庭收入、政策执行满意度、户主职业、邻里关系、现有宅基地面积、搬迁以后的生活成本及从众心理,结合指标获取难易程度及代表性,选取了表征农户意愿的指标。(3)研究区可分为优先整理区、重要整理区、次要整理区及最后整理区4类,它们可整理的理论潜力依次为718.63hm^2,861.85hm^2,875.70hm^2及136.03hm^2。

基于时序分区的时态索引与查询

时态索引作为一种高效管理和检索时态数据的有效手段,一直是时态数据领域的研究热点.提出了一种基于时序分区的时态索引技术TPindex.首先将海量时态数据的时态属性映射到二维平面上,对平面上的"有效时间"点进行采样处理,通过使用自上而下,自左而右的时序分区方法将平面划分成若干个均匀的区域.其次,使用基于拟序关系的线序划分算法对每个分区中的数据构建数据结构,并建立基于"有效时间戳"的全区索引,实现"一次一集合"的数据查询操作.再次,还提出了使用分文件存储线序索引的模式将分区线序索引磁盘化,同时可以结合多线程技术并行处理数据,充分利用现代化硬件资源以满足海量数据下的高性能需求,提高索引性能.另一方面,我们还研究了海量时态数据下TPindex的增量式更新操作.最后,设计相应的仿真实验,通过与现有的代表性工作进行对比评估,验证了所提出方法的有效性和实用价值.

高标准基本农田建设时序与分区研究

针对集中连片、设施配套、高产稳产和生态良好等高标准基本农田的特点,以地块为研究尺度,从基本农田的立地条件、自然质量条件、基础设施等3方面选取12个指标,运用TOPSIS方法和因素组合法确定县域高标准基本农田建设的时序和建设类型区,最后以河北省卢龙县为例进行实证。结果表明,卢龙县高标准基本农田建设时序安排上近、中、远期建设区的面积分别占总面积的39.23%、22.44%、38.33%;卢龙县高标准基本农田建设可划分为3个建设区,即土地平整重点建设区、灌溉与排水重点建设区、农田防护与生态环境保持重点建设区,各区所占比例分别为20.68%、50.25%和29.07%。研究方法可为高标准基本农田建设项目遴选提供参考依据。

Analysis of Abnormal Characteristics of Regional Crustal Deformation before the Menyuan MS6.4 Earthquake by GPS Continuous Data

In order to study the characteristics of crustal deformation around the epicenter before the 2016 M_S6. 4 Menyuan earthquake,the GPS continuous stations of the period from 2010 to 2016 were selected according to the observation data of the tectonic environment monitoring network in Chinese Mainland. The deformation characteristics of the crust before the earthquake were discussed through inter-station baseline time series analysis and the strain time series analysis in the epicentral region. The results show that a trend turn of the baseline movement state around the epicenter region occurred after 2014,and the movement after 2014 reflects an obvious decreasing trend of compressional deformation.During this period,the stress field energy was in a certain accumulation state. Since the beginning of 2014,the EW-component linear strain and surface strain rate weakened gradually before the earthquake. It shows that there was an obvious deformation deficit at the epicentral area in the past two years,which indicates that the region accumulated a high degree of strain energy before the earthquake. Therefore,there was a significant background change in the area before the earthquake. The results of the study can provide basic research data for understanding the seismogenic process and mechanism of this earthquake.

Characteristics of the May 12,2008 Wenchuan M_S8.0 Earthquake Sequence and Discussion on Relevant Problems

The aftershock activity of the May 12, 2008 Wenchuan Ms8.0 Earthquake Sequence shows an obvious segmented feature. Most of the large aftershocks were distributed in the north and south parts of the aftershock zone. Thrusting was dominant with a small amount of strike-slip component in the south part. The aftershock activity decayed gradually, presenting the sequence features of a mainshock-aftershock pattern. The north part was the ending area of the malnshock fracture where strike-slipping was dominant, showing an obvious swarm feature. Therefore it became the major area for large aftershocks. The modulation of the earth tide on aftershock activity is remarkable; most large aftershocks occur during the period of flood and neap tide. The time period around 16：00 was the dominant occurring time for large aftershocks. The p-value, a parameter of modified Omori formula, increases gradually with time, and reaches about 1 at the end. Based on previous study, the sequence patterns, magnitude of maximum aftershock, as well as the duration of aftershock activity has been discussed. The primary results also show that the magnitude difference between the maiushock and the maximum aftershock is proportional to the rupture size of the maiushock for huge earthquakes of about Ms8.0. This means that when the magnitudes of the earthquakes are nearly the same, large rupture size corresponds to sufficient energy release.