顾及障碍空间距离和区域差异的元胞自动机城市扩展模型构建

结合城市空间的区域异质性特征,提出了顾及障碍空间距离和区域差异的CA城市扩展模型。以武汉市中心城区为例,在精确度量障碍空间的基础上,根据城市用地的不同形态和作用方式进行元胞空间的区域划分,构建动态的演化规则。实证表明,新模型能比较真实地模拟城市的扩展过程,结果可靠。     

基于遥感与GIS的干旱区石油城镇用地扩展分析——以克拉玛依市独山子区为例

以克拉玛依市独山子区为例,采用1989年、1999年、2006年三期Landsat TM遥感图像数据为基础数据源,在遥感和GIS技术的支持下,阐述了提取研究时段内城镇用地扩展数据的技术路线,并结合城市地理学方法,进一步对城镇空间扩展进行了定量分析,结合社会经济统计数据,对独山子区城市用地扩展驱动力进行了尝试性分析,并对以后城市扩展提出对策,以期探讨遥感与GIS技术用于城市地理学的方法和过程。     

首都圈及邻近区域地震活动能量场研究

通过对首都圈及邻近区域的地震资料采用自然正交簇解析方法,分析了中强以上地震前地震活动能量时间因子和能量空间分布异常情况,发现自然正交簇解析的方法能够较好地提取中强震前的地震异常信息,虽然有些异常规律并不十分明显,其物理机制也不是十分明确,但是该方法还是一种有效的、值得探索的地震预测方法.     

Closing yield gap is crucial to avoid potential surge in global carbon emissions

Global greenhouse gas (GHG) emissions models generally project a downward trend in CO₂ emissions from land use change, assuming significant crop yield improvements. For some crops, however, significant yield gaps persist whilst demand continues to rise. Here we examine the land use change and GHG implications of meeting growing demand for maize. Integrating economic and biophysical models at an unprecedented spatial resolution, we show that CO₂ emissions from land conversion may rise sharply if future yield growth follows historical trends. Our results show that ~4.0 Gt of additional CO₂ would be emitted from ~23 Mha agricultural expansion from 2015 to 2026, under historical yield improvement trends. If yield gaps are closed expeditiously, however, GHG emissions can be reduced to ~1.1 Gt CO₂ during the period. Our results highlight the urgent need to close global yield gaps to minimize agricultural expansion and for continued efforts to constrain agricultural expansion in carbon-rich lands and forests.     

Modelling the Cone Penetration Test in sand using Cavity Expansion and Arbitrary Lagrangian Eulerian Finite Element Methods

The paper considers two techniques to model the Cone Penetration Test (CPT) end resistance, q_c in a dense sand deposit using commercial finite element programmes. In the first approach, Plaxis was used to perform spherical cavity expansion analyses at multiple depths. Two soil models, namely; the Mohr–Coulomb (MC) and Hardening Soil (HS) models were utilized. When calibrated using simple laboratory element tests, the HS model was found to provide good estimates of q_c. However, at shallow depths, where the over-consolidation ratio of the sand was highest, the relatively large horizontal stresses developed prevented the full development of the failure zone resulting in under-estimation of the q_c value. The second approach involved direct simulation of cone penetration using a large-strain analysis implemented in Abaqus/Explicit. The Arbitrary Lagrangian Eulerian (ALE) technique was used to prevent excessive mesh deformation. Although the Druker–Prager soil model used was not as sophisticated as the HS model, excellent agreement was achieved between the predicted and measured q_c profiles.     

吉林烟筒山膨润土改型试验研究

以吉林磐石烟筒山膨润土为原料,采用Na2CO3为钠化剂,研究了Na2CO3用量、反应时间与改型膨润土膨胀倍、胶质价的关系。实验结果表明当Na2CO3的用量为膨润土的3%,钠化时间为5 min,即可得到很好的结果。     

Analysis of gravity source moment inversion. Part II: Usinga priori information about the source

The method of moment inversion, based on the approximation of the gravity anomaly by thetruncated series obtained from its multipole expansion, uses, implicitly,a priori information about the anomalous body. The series truncation imposes a regularizing condition on the equipotential surfaces (produced by the anomalous body), allowing the unique determination of some moments and linear combinations of moments that are the coefficients of the basis functions in the multipole expansion series. These moments define a class of equivalent distributions of mass. The equivalence criterion is based on the misfit between the observations and the field produced by the series truncated at a prefixed maximum order for the moments. The estimates of the moments of the equivalent distribution are shown to compose the stationary solution of a system of first-order linear differential equations for which uniqueness and asymptotic stability are guaranteed. Specifically for the series retaining moments up to second order, the implicita priori information introduced requires that the source have finite volume, be sufficiently distant from the measurement plane and that its spatial distribution of mass present three orthogonal planes of symmetry intersecting at the center of mass. Subject to these hypotheses, it is possible to estimate uniquely and simultaneously the total excess of mass, the position of the center of mass and the directions of the three principal axes of the anomalous body.     

全球构造研究的简要回顾

全球构造研究可分为：（１）１９世纪后期“固定论”占统治地位阶段；（２）２０世纪６０年代前“活动论”曲折发展阶段；（３）６０年代以来板块学说占统治地位阶段。当代全球构造研究以地球深部构造与物质研究为关键。日本学者提出了“幔柱构造”和新的全球构造体系，其它学者提出了不同形式的“膨胀论”和“脉动论”。全球构造研究应注意思想创新，冲破均变论思想的局限性。建议以突变观点和“阶段论”为依据，使观察、推理和实验三者适当配合，发挥优势，逐步建立自己的地球动力学及其演化模型。     

遥感影像融合技术在城市发展研究中的应用

利用多源数据融合的技术方法，完成了上海市城市发展态势图，为卫星遥感在城市发展研究的应用作了初步尝试，并结合城市发展态势图对上海城市边缘界定及城市发展速度进行了分析，取得了较为满意的结果。