Revisiting the Relationship Between Urbanization and Economic Development in China Since the Reform and Opening-up

The relationship between urbanization and economic development has become a hot topic in the scientific community due to its great practical significance,and economic and social value.However,this relationship continues to change dynamically.In the new stage of urbanization,it is urgent to reveal the causal relationship quantitatively and diagnose the future direction systematically.Based on this,this paper calculates the contribution rate of China’s urbanization to economic development from 1978 to 2019 and uses the panel data cointegration test method to explore the causal relationship between urbanization and economic development in China.The study has three principal results.First,the contribution rate of urbanization to economic growth has maintained the overall growth trend from1978 to 2019,but the growth rate of urbanization’s contribution to economic growth has been relatively low since 2012.It is an important reason that the real estate sector has moved into a new stage of transformation.Second,the cointegration test shows that economic development is a significant factor in advancing urbanization and the urbanization is the product of economic development.Urbanization has a positive feedback effect on economic development,but this effect does not pass the 5%significance level test.The impulse response function shows that the impact of urbanization on economic development is relatively small and stable,indicating that it is limited that the boost of economic development by land-centered urbanization.Third,China’s urbanization and economic development have both shown rapid growth for some time,but their relationship is still the low level of coordination,which has also led to a downward trend in the contribution of new-type,people-oriented urbanization to economic growth in recent years.In the future,China’s urbanization and economy need to maintain relatively medium-low speed growth in the medium-long term,and we should boost the coordinated development of urbanization and economy from low level to high level.     

基于自适应核密度的贝叶斯概率模型岩性识别方法研究

准确地刻画岩石类型及其结构关系可以为能源矿产勘探、深部结构与构造等研究提供重要信息.目前利用地球物理技术可以通过不同岩石对应的物性参数(如密度、磁化率、电阻率、速度等)之间的差异进行岩性识别,但是不同岩石物性往往存在一定程度的重合,利用单一物性进行岩性识别的结果不够准确,因此利用多源数据进行岩性识别具有重要的意义.贝叶斯方法属于统计分类方法,依靠概率进行分类,概率密度的计算依靠样本属性之间的相互联系.基于此,我们将基于自适应核密度估计的贝叶斯概率模型引入到岩性识别中.该方法对于多类不同物性参数具有良好的适应能力,预测的岩性分类结果带有概率参数,可以存在模糊区间,提供多种岩性分类结果.该方法具有较强可扩展性,可以同时处理参数和非参数信息,使得已知地质信息以及物性参数得到最大化的利用.实验证明该方法的岩性识别结果较好,相比于传统高斯算法和固定带宽核密度估计,自适应带宽的核密度估计获得的分类结果更稳定、更准确.     

顾及共享交换的行业地理空间数据关联模式

在数字城市、"多规合一"、大数据建设推动下,政府管理部门和行业部门对地理空间数据共享有强烈需求.然而,其行业特殊性导致行业部门所拥有的数据无法进行有效融合与交换,数据共享成本大.以不改变行业原有的数据规范,实现行业之间地理空间数据的及时有效共享与交换为目标,通过分析行业地理空间数据特征,提炼数据的关联特征,认知并结构化...     

地球磁层顶磁场重联的动力学过程

用三维可压缩MHD数值模拟研究了在磁场重联过程中电子压力梯度项的效应研究结果发现在较高等离子体β,较小离子惯性尺度条件下,广义欧姆定理中压力梯度项在重联过程的作用不可忽略.在磁重联过程中,压力梯度项虽然没有明显改变磁场拓扑结构和重联速度,但它使电子和离子速度明显增大.由于在离子惯性尺度下,离子和电子运动解耦,电子是电流的主要载流子,所以场向电流也增大,并导致核心磁场明显增大.考虑到场向电流是磁层电离层耦合的一个重要因素,所以电子压力梯度项的引入加强了行星际磁场南向期间磁层电离层的耦合.电子压力梯度项还在重联区激发了波动,该波动可向重联区外传播.     

储集层中高压流体引爆强地震的机理——以5.12汶川地震为例

目前产生地震的机制仍以弹性回跳说为主：地震是因为断层错断使岩层的弹性能释放而引发。但越来越多的学者开始质疑,仅断层错断后的弹性能,是否真能达到实际地震所释放的巨大能量。因此,有必要探讨地震初动后破坏性强震的性质及其真正的能量来源。文章根据沉积地层中的储集层及其压力的特点分析得出,储集层内含有大量的高压流体,其压力在一定条件下可以释放出来,产生流体物理爆炸,有可能是强震能量的重要组成部分。通过计算得出,当断层破裂并刺穿面积较大的储集层时,其压力释放所产生的弹性能可以达到震级8.0以上地震所释放的能量;人为的工程活动也可引发小规模的流体压力的释放现象,如钻井时的井喷、水力压裂会诱发有感地震等。同时,文章根据对距离震中较近的地震台的波形及传播射线路径分析认为,强震波动可能不是横波S波,而是涨缩波P波,据此不能排除强震是由爆炸所致。综合汶川地震多个台站记录到的地震波的时间域和频率域特征、地面观测到的爆炸现象、地震后科学钻探获得的岩心等大量直接或间接证据,说明了这种流体爆炸能量释放的可能性。最后,文章提出了地震活动可分为三个阶段：微破裂阶段Ⅰ,该阶段有流体活动,并可产生动电效应,但未触发地震初动;地震初动后的断裂破裂阶段Ⅱ;由流体压力释放产生地震强震阶段Ⅲ。     

求解GM(1,1)模型新总体最小二乘算法

在GM(1,1)模型中系数矩阵和观测向量都是由原始序列组成的。系数矩阵中同样是有误差的,与观测向量中的误差一样,亦来源于原始序列,即它们误差同源。不同位置的相同元素应该有相同的改正数,采用传统总体最小二乘求解则不能达到此目的。针对这一缺陷,推导了一种新的总体最小二乘算法;并且通过算例验证了新方法的可行性和有效性。     

西藏自治区的构造地质演化和成矿地质单元划分

西藏自治区现代意义的地质调查和研究工作始于和平解放后的1951年。经过近60多年来几代地质人的努力,西藏地质工作从无到有,已取得了辉煌的成就,目前西藏自治区的地质概貌和矿产资源概貌已基本查清。本文即是《西藏矿产志》编写工作中对这两个概貌的基本总结。     

基于抗差估计的实时单站GPS同震速度获取方法

基于实时单站GPS载波相位历元差分测速模型,引入抗差最小二乘估计,并根据IGGⅢ方案选择合适的等价权因子来削弱小周跳和粗差对结果的影响,并采用一组静态数据和2011年日本"3.11"地震期间MIZU站的高频数据对算法进行测试。结果表明,在含有小周跳和粗差的情况下,抗差最小二乘估计能够明显改善解算速度,可以实时获取测站毫米级的同震速度。     

重力场数学拟合模型解的影响因素探究

为了提高地球重力场模型不适定方程求解的精度,该文采用谱分析方法从级数展开阶数、数据采样率及数据缺失量3个方面探索影响数学拟合效果的根本因素:从常用的三角级数及勒让德级数模型出发,引出重力场拟合模型球谐函数模型,观察在改变级数展开阶数、数据采样率及数据缺失量等情况下所对应设计矩阵谱结构的变化,并从微观上研究影响误差分配的有关因素及最小奇异值对误差的决定性作用,为探求重力场模型解不准的原因及实现更高精度的全球重力场模型的建立提供参考。     

Research on Formation Mechanisms of Hot Dry Rock Resources in China

As an important geothermal resource, hot dry rock(HDR) reserves have been studied in many countries. HDR resources in China have huge capacity and have become one of the most important resources for the potential replacement of fossil fuels. However, HDR resources are difficult to develop and utilise. Technologies for use with HDR, such as high–temperature drilling, reservoir characterisation, reservoir fracturing, microseismic monitoring and high–temperature power stations, originate from the field of oil and drilling. Addressing how to take advantage of these developed technologies is a key factor in the development of HDR reserves. Based on the thermal crustal structure in China, HDR resources can be divided into four types: high radioactive heat production, sedimentary basin, modern volcano and the inner–plate active tectonic belt. The prospective regions of HDR resources are located in South Tibet, West Yunnan, the southeast coast of China, Bohai Rim, Songliao Basin and Guanzhong Basin. The related essential technologies are relatively mature, and the prospect of HDR power generation is promising. Therefore, analysing the formation mechanisms of HDR resources and promoting the transformation of technological achievements, large–scale development and the utilisation of HDR resources can be achieved in China.