The three geochemical series of tin deposits and their evolution

Three geochemical series, i.e., the siderophile, chalcophile and lithophile series, have been classified for tin deposits based on geological-geochemical data on tin mineralization in China. The three series are distinct from each other in geological settings, ore-forming elements, minor elements, REE, stable isotopes, ore-forming fluids and physicochemical conditions. The formation of tin deposits of the three series could be closely related to the evolution of the Earth’s crust.     

中国城市碳排放强度的空间溢出效应及驱动因素探究（英文）

In this study, we adopt kernel density estimation, spatial autocorrelation, spatial Markov chain, and panel quantile regression methods to analyze spatial spillover effects and driving factors of carbon emission intensity in 283 Chinese cities from 1992 to 2013. The following results were obtained.(1) Nuclear density estimation shows that the overall average carbon intensity of cities in China has decreased, with differences gradually narrowing.(2) The spatial autocorrelation Moran's I index indicates significant spatial agglomeration of carbon emission intensity is gradually increasing; however, differences between regions have remained stable.(3) Spatial Markov chain analysis shows a Matthew effect in China's urban carbon emission intensity. In addition, low-intensity and high-intensity cities characteristically maintain their initial state during the transition period. Furthermore, there is a clear "Spatial Spillover" effect in urban carbon emission intensity and there is heterogeneity in the spillover effect in different regional contexts; that is, if a city is near a city with low carbon emission intensity, the carbon emission intensity of the first city has a higher probability of upward transfer, and vice versa.(4) Panel quantile results indicate that in cities with low carbon emission intensity, economic growth, technological progress, and appropriate population density play an important role in reducing emissions. In addition, foreign investment intensity and traffic emissions are the main factors that increase carbon emission intensity. In cities with high carbon intensity, population density is an important emission reduction factor, and technological progress has no significant effect. In contrast, industrial emissions, extensive capital investment, and urban land expansion are the main factors driving the increase in carbon intensity.     

Spatial spillover effect and driving forces of carbon emission intensity at the city level in China

Journal of Geographical Sciences - In this study, we adopt kernel density estimation, spatial autocorrelation, spatial Markov chain, and panel quantile regression methods to analyze spatial...     

基于流空间视角的城市群空间结构研究——以珠三角城市群为例

随着现代交通、通信以及信息技术的发展,基于网络社会的“流空间”成为研究城市群空间结构的重要理论前沿。借助珠三角城市群9个城市的人流、物流、资金流和信息流数据,对珠三角城市群空间结构的现状和发展趋势进行综合性判断。研究发现：① 珠三角城市群的空间结构现状在“点-线-网-面域”4个层面均呈现出明显单极化态势,广州市是“流空间”视角下珠三角城市群的核心,区域网络结构呈现出“缺位型金字塔形结构”;② 珠三角城市群网络的未来发展中位于不同层级的城市将起着不同的作用,其中广州、深圳、东莞等城市对空间结构发展起着导向性作用,而佛山、中山等城市将承担着联系中转站功能;③ 珠三角各城市的流度辐射区一体化明显,各城市辐射影响区的空间形态也表明了各城市的功能圈和势力范围。未来随着全球化趋势和区域一体化政策的加强,珠三角城市群的集聚效应将不断转化为扩散效应,将极大提升珠三角城市群对全球范围内资源的吸聚和配置能力,助力珠三角城市群走向网络化的发展时代。     

海底沉积物在应力-应变过程前后的微区变化特征

自1925年太沙基提出的“蜂窝状结构”概念以来,有关土和沉积物微结构分类研究取得了一系列重大成果[1-3].高国瑞[4]则研究分析了我国沿海海相沉积物的微结构类型和工程性质,梁元博等[5]提出典型堆垒结构和颗粒孔隙取向的海洋沉积物微结构模式,卢博等[6-7]对南海海底沉积物微结构影响物理力学性质以及提出的微结构分类研究,丰富了我国海底沉积物结构和微结构的微区分析研究.本文试图通过沉积物在应力一应变过程中的微区变化特征分析研究,为海底工程地质实践服务.     

The Three Results of Sound Velocity Variance in Sediments During Controlled Stress-strain Testing from the South China Sea

Sound velocity in each type of seafloor sediment from the South China Sea varies with the development of strain in the controlled stress-strain course. Experiments show that there may exist three cases for the maximum sound velocity: (1) it appears at the stress peak; (2) it appears in the phase of no load; and (3) it appears at the end of the strain course. These results are related to physical-mechanical properties and structure of sediments.     

Sound Velocity of Seafloor Sediment and its Response under Axial Stress-Strain

The results of axial stress-strain measurements made from short columnar samples of seafloor shallow surface sediment in the southern South China Sea area indicate that there are three kinds of variations in the longitudinal wave sound velocity, which are related to such characteristics as physical-mechanical properties, grain contact status and grain structure and microstructure of the submarine shallow surface sediment. This study may make theoretical contributions to further understanding the reliability of various submarine sediments in the southern South China Sea as bearing interfaces and such scientific objectives as phonotelemetering and remote sensing of the engineering mechanical properties of seafloor sediment.     

中国城市土地城市化水平与进程的空间评价

土地城市化在中国快速而持续的城市化进程中扮演的支撑与制约角色越来越明显,但目前对土地城市化水平的测度框架依然没有明确统一的认识。基于此,提出了一种可供参考的土地城市化率的概念与测度方法,并确定其阈值。以中国656个城市的城区为研究单元,以2000年和2010年城市建设用地面积为基本数据,采用城市建设用地面积、土地城市化率、城市土地扩展面积和城市土地扩展速度分别评价了中国城市的土地城市化规模、水平、绝对进程和相对进程的空间分异格局。并分析了九大类城市建设用地类型对土地城市化进程的贡献率。结果表明：① 近10年来,中国城市总体土地城市化率提高近一倍,由“金字塔式”等级分布逐渐转为“钥匙式”的分布格局;东部地区城市建设用地规模较大,但城区面积更大,使其土地城市化率的数值较低。② 省会城市和沿海城市群的城市土地扩展面积最大,呈现出行政等级式分异和空间集聚式分异的空间格局;城市土地扩展速度呈现出沿海城市群与其他城市分异的空间格局。规模越大的城市,土地城市化进程越明显。③ 近10年来中国土地城市化进程的两大核心用地增长类型是居住用地和工业用地;规模越大的城市,工业用地增长的驱动作用越显著;中西部地区和中小规模城市以居住用地增长为核心,沿海城市群和重要交通轴线城市以工业用地增长为主。     

扬州市住宅价格空间分异的影响因素与驱动机制

构建包含20个评价因子、4 个影响因素和4 个预期修正因素在内的城市住宅价格空间分异影响因素评价体系,基于评价因子和预期修正,分别得出单户住宅档次与水平、小区建设档次与水平、区位与生活便利性、周边景观与环境等4 个影响因素强度的得分,并分析其空间分异格局。以2012 年扬州市1305 个小区的平均住宅单价为因变量,4 个基本影响因素得分为自变量,进行回归分析,探索所有住宅及各子市场价格分异的主要因素,并分析其驱动机制。结果表明：① 4 个影响因素强度格局明显不同,住宅自身因素的格局呈现中心低外围高的圈层式分异,而外部作用因素强度呈现中心高外围低、西高东低的扇型与圈层相结合式空间分异格局;② 扬州市总体住宅价格空间分异的核心影响因素是小区建设档次与水平,不同类型住宅子市场的价格影响因素各不相同;③ 扬州市住宅价格空间分异的主要驱动力是特定住宅类型与档次建设的区位指向、特定收入阶层的空间集聚、公共物品投资的空间差异、城市居住用地扩展与城市更新的区位指向。     

Vertical Variations of Core Sound Velocity: Evidence of Paleooceanographic History Since the Pleistocene Epoch

The vertical variations in the borehole core sound velocity (Cp) of the submarine sediments are related to the events of marine transgression and regression in the geologic history. This article establishes the vertical variation of Cp curve for the borehole sound velocity in the northern South China Sea continental shelf and the East China Sea continental shelf, thus providing evidence for revealing at least (3) sedimentary cycle events of marine transgression and regression occurring in the west Pacific marginal sea since the Pleistocene Epoch. The sound velocity of marine sediments brought in the course of marine transgression is lower (1450-1510 m/s) while that of continental sediments formed in the course of marine regression is higher (1650-1720 m/s).