政策主导下的区域土地利用转型过程与机制——以中国东北地区为例

从构建政策主导下区域土地利用转型解释框架入手,以东北地区为例,探究政策主导下区域土地利用转型机制。结果表明：① 1995—2015年,东北地区经济社会发展可划分为“经济低速增长,城镇化与人口发展停滞期”与“经济波动,城镇化稳定发展,人口转型期”两大阶段。② 伴随经济社会转型,东北地区发生土地利用转型。转型特征主要表现为：在数量上,区域耕地规模持续扩张,但增速放缓,耕地内部水田占比上升;林地与草地规模持续缩减,但下降速度放缓;区域建设用地加速增长,增长主体由农村建设用地转变为城镇建设用地。在空间上,耕地分布重心持续向东北方向移动,林地与未利用地分布重心向西南方向移动,建设用地与草地分布重心呈现显著的转折特征。③ 东北地区土地利用转型是区域内不同土地利用类型在空间上由冲突到协调的持续性重构过程。区域功能定位以及经济现代化与城镇化是导致土地利用转型的核心因素。政策主导下的区域土地利用转型是政策引导下的社会-生态反馈路径与政策影响下的社会-经济变化诱发路径综合作用的结果,两者间存在耦合与拮抗过程。前者决定区域土地利用转型的方向,后者决定区域土地利用转型的速度与强度。     

超越“演化”:老工业区重构研究进展与范式反思

老工业区重构是经济地理学的重要研究议题。在全球化步伐放缓和全球制造业下行的宏观背景下,老工业区已愈来愈成为各国发展战略制定的核心对象。对近十年有关老工业区重构的中外文献进行细致梳理,指出了当下研究存在范式应用多元化的趋势,但这些范式在概念使用、尺度聚焦、时空侧重和机制解释上存在显著差异,缺乏相互融合和优势互补,面临现实应用瓶颈。特别是,长期用于解释老工业区重构的演化经济地理学,因其忽视多尺度-多主体-多分析单元的能动性作用而难以有效解释重构过程、机制、结果及其背后的地理性。本文将转型研究中的多层次视角同演化范式相结合,提供了一种具备上下因果辩证解释力的多尺度分析框架,能有效解释老工业区重构问题。在此基础上,探讨了未来研究方向。     

论乡村聚落转型

在人类聚居学、人地关系地域系统和土地利用转型等理论基础上,从物质-社会空间耦合的视角阐释乡村聚落转型的概念内涵及其表征要素,揭示不同历史阶段乡村聚落空间从同质同构转向异质异构的基本特征,剖析外缘拉力、内生推力和系统突变力综合作用下的乡村聚落转型驱动机制,设计乡村振兴目标导向下乡村聚落转型分区、分类、分模式的路径体系。研究认为,乡村聚落转型应该调节物质空间和社会空间的协同演进,着力提升乡村聚落的内生动力和应对外界干扰抵御、适应和转型的能力,分类、有序的推进乡村聚落多元化发展并驱动乡村振兴。     

集成GIS的元胞自动机在城市扩展模拟中的应用

元胞自动机CA(Cellular Automata)是一种"自下而上"的动态模拟模型,具有模拟城市复杂系统时空演化过程的能力。CA和GIS的集成使二者在时空建模方面相互补充,能使CA模拟结果可视化显示。这里以郑州市为例,设计了城市CA模型,借助VB 6.0和MapX 5.0建立了一个与GIS无缝集成的2维CA模拟系统,并结合郑州市2005~2007年遥感影像图和土地利用图,对郑东新区进行了模拟,取得较好的效果。     

合肥形变台跨郯庐断裂短水准异常研究

以合肥形变台短水准测量场地各基岩点与检测线路端点(基岩)组成水准环线进行连测,利用重复观测资料,估算各点稳定度.研究认为,观测资料长期趋势变化是西端A点受环境条件改变的干扰造成的.     

南京地震台地电阻率异常变化分析

南京地震台电阻率NS向观测2005年4月初出现明显的转折变化,经过外线路巡查、仪器标定及对比分析后认为,该变化是地电布极区附近的东新村拆迁,自来水管网拆除引起,非背景场变化,也非地震异常.     

赤道东太平洋海温对东亚～西北太平洋温带气旋的影响

本文分析了东亚～西北太平洋较强温带气旋的气修特征及其与赤道东太平洋海温的关系。得出,厄尔尼诺年或厄尔尼诺持续年,较强温带气旋偏多的对应关系占找优势。但当副热带高压偏强时,则较强温带气旋偏少。     

Photon scattering in the solar ultraviolet lines of He i and He ii

Observations made with the Coronal Diagnostic Spectrometer (CDS) onboard the Solar and Heliospheric Observatory ( SOHO ) are used to investigate the behaviour of the intensities of the emission lines of He  i , He  ii and O  iii at the quiet Sun-centre and at  θ= 60°  towards the equatorial limb. The aim is to examine the possible effects of photon scattering on the spatial variation of the optically thick helium lines. At the quiet Sun-centre, we find that, in agreement with previous work, the ratios of the intensities of the He  i 584-Å and He  ii 304-Å lines to those of the O  iii 600-Å line decrease systematically as the intensity of the O  iii line increases. However, we find that the dependence of these ratios on the O  iii intensity is not unique, but differs between the individual regions studied. Similar results are found at  θ= 60°  . We have also used line intensities and intensity ratios to investigate limb-to-disc effects and variations across a sample of supergranulation cell boundaries and adjacent cell interiors at both locations. The results do not exclude photon scattering as the cause of the larger observed ratios in cell interiors. The differences between the apparent widths of boundaries in O  iii at Sun-centre and 60° show that the emitting material is extended in height, which will aid the process of scattering into cell interiors. Photon scattering could also account for the lack of oscillations in the He  i intensities in a cell interior studied by Pietarila & Judge. Three-dimensional radiative transfer calculations in chosen geometries are now needed to account for the observations in detail.     

Polymetamorphism and isobaric cooling of pelitic schists from the Annex sulphide deposit, Gordonia Belt, South Africa

Abstract Muscovite-poor pelitic schists in the wallrocks of the Proterozoic Annex sulphide deposit, near Prieska, South Africa, contain peak metamorphic assemblages including Crd + Bt + Sil, St + Sil + Bt, Crd + St + Bt and, rarely, Ky + St ° Crd. All rocks include oligoclase, quartz and commonly Fe–Mn garnet, with or without muscovite. Peak assemblages, assigned to M2 regional metamorphism in the Gordonia Belt (Namaqua Province), are syn- to post-kinematic with respect to the main S2 fabric although larger staurolite grains contain S1 inclusion trails. Garnet–biotite thermometry, utilizing corrections for Fe³⁺, Mn, Al^VI and Ti, yields peak temperatures of 571–624°C at pressures of 4.5–6.0 kbar. Consideration of the sympathetic variation of X_Mn in garnet with X_Mg in biotite and the preserved zoning patterns in prograde garnets, together with the inferred prograde transition from kyanite to sillimanite, indicates that heating occurred during mild decompression to the M2 metamorphic peak. Sillimanite and cordierite grew last in the prograde sequence, possibly related to a pulse of thermal metamorphism (M3) that is found along the margin of the Keimoes Suite batholith to the north. Retrograde assemblages, including Ms + Ky + Chl + Qtz (after Crd + Bt), Ky + Ms (after Sil) and Chl + Ms (after St) indicate a period of isobaric cooling (M4a) terminated by rehydration in the kyanite stability field at about 500°C. The size difference between prograde (1–2-mm) and retrograde (0.05–0.1-mm) mineral grains indicates substantial undercooling below equilibrium positions of relevant retrograde reactions prior to rehydration, and explains why cordierite that grew during M2 is almost completely destroyed. Post-M4a regrowth of staurolite and garnet (M4b) is spatially linked to sites of M4a rehydration. It reached temperatures of 510–530°C, remaining within the stability field of kyanite. A best fit of the observed textural history to the Namaqua orogenic cycle involves collision and heating (M2/D2) followed by granite intrusion (M3), rifting (M4a) and renewed heating due to crustal loading during volcanism (M4b). The P–T path for the Annex region is consistent with those derived from elsewhere in the Gordonia Belt and, with modification, to that published already for the nearby Prieska Copper Mines.     

Coupling of deformation and reactions during mid-crustal shear zone development: an in situ frictional–viscous transition

A well preserved strain and reaction gradient records the progressive transformation of a megacrystic Kfs+Cpx+Opx+Bt₁±Qtz syenitic pluton to a strongly sheared Kfs+Act+Bt₂+Ab+Qtz tectonite within the exhumed Norumbega Fault System, Maine, USA. Detailed microstructural analysis indicates that fracturing and localized fluid infiltration initiated the deconstruction of the existing K-feldspar and two-pyroxene load-bearing framework, and that feedback among metamorphic reactions, fabric development and enhanced permeability during progressive shearing led to the development of an interconnected, biotite- and actinolite-rich foliation. The activation of dislocation creep in biotite and quartz, and dissolution–precipitation creep in actinolite and feldspar, with increasing strain ultimately resulted in a transition from dominantly frictional to dominantly viscous deformation processes. Petrological data show that various scales of geochemical disequilibrium exist across the strain and reaction gradient, and that reaction progress was limited by slow chemical diffusion during the early stages of deformation. Petrological modelling results indicate that the existing plutonic assemblage was metastable at mid-crustal conditions, and that fluid infiltration and deformation allowed the product assemblage to advance towards chemical equilibration. Comparison of the observed microstructures and deformation mechanisms with experimental and numerical modelling results suggest that the development of an interconnected biotite-dominated fabric probably caused a major (up to three fold) reduction in bulk rock strength and localization of strain into the foliated margin.