数字金融与城市群高质量发展--基于“U”形关系的解释

精准细分数字金融及其各分维度指数对城市群高质量发展的影响机理,对于充分发挥数字金融对城市群高质量发展的驱动力具有重要的现实价值。运用2011—2018年中国19个城市群211个城市的面板数据,采用熵权法测度各城市群高质量发展水平,借助面板分位数回归模型实证考察数字金融和各分维度指数对城市群高质量发展的影响。研究发现:(1)数字金融总指数对城市群高质量发展的影响在全样本和区域样本均呈现显著的“U”形路径;(2)全样本层面数字金融的覆盖广度、使用深度以及数字化程度等各分维度指数长期来看均对城市群高质量发展水平的提升具有正向作用;(3)数字金融各分维度指数对城市群高质量发展的影响具有明显的区域异质性。因此,必须加快“数字中国”建设,充分释放数字金融在城市群高质量发展中的红利,各城市群要依据数字金融发展的顶层设计,因地制宜,构建数字金融驱动城市群高质量发展的长效机制。

面向DEM地形复杂度分析的分形方法研究

在基于栅格DEM数据的基础上,应用分形几何学方法,采用元分维模型理论,提出一种描述DEM地形复杂度的分形分析方法,并得出分析指标———地形分维指数(TFI)。实验证明,该指标可以有效描述栅格DEM数据反映的地形变化特征,分析窗口由小到大的规律性变化反映出地貌从微观到宏观的变化情况,因此其既可以作为对栅格DEM所描述地形进行评价的坡面因子,又可以作为基于DEM的地貌类型区自动划分的参照依据。

江苏省乡村聚落演化的多尺度特征与空间关联性分析

乡村聚落演化与发展是农村社会特定人地关系的集中体现,其空间关联性是乡村聚落规划与重构的基础。该研究以江苏省为例,综合运用核密度分析、景观分维指数与空间热点探测方法,分析2009-2018年江苏省乡村聚落演化的多尺度特征与地域分异性规律,定量测度乡村聚落演化与不同地理要素的空间关联性及其增减变化的空间自相关特征。研究结果表明:江苏乡村聚落变化呈现出“减少面广、增加集聚”的典型特征,乡村聚落增减变化的密度表现出沿江沿海的轴线走向;县域单元乡村聚落以不规则分布为主且差异较为显著,苏南地区乡村聚落形态规整度整体相对更优;乡村聚落增减变化在道路、水源和城镇可达性时间大于60 min范围内聚落增减规模比例最大,但在整体上并未呈现出明显的地理空间可达性指向,乡村聚落变化更多以农户自组织方式进行;江苏大多县域乡村聚落变化处于不显著的随机状态,南京市是乡村聚落增减变化的典型冷热点区,而南通市则是乡村聚落增加热点区。研究有助于深入理解社会经济转型期乡村聚落演化的时空关系与农户决策行为,促进乡村聚落布局优化和空间有序重构。

崂山风景区景观要素空间格局及其动态分析

利用崂山风景区的林相图和 1983年、1991年、2 0 0 1年 3期实地调查资料 ,在ARC/INFO的支持下 ,对崂山风景区的景观格局进行了动态分析。结果表明 :(1)景观多样性较低 ,整个景观被黑松与落叶松林占据了80 %以上的面积。但从 1983～ 2 0 0 1年的变化上看 ,景观多样性有加大的趋势 ;(2 )黑松的面积变化很小 ,但落叶松林面积有所下降 ,刺槐、赤松、空地面积有所加大 ;(3)分维指数主要在 1.2 5～ 1.35 ,说明整体斑块的边缘比较规则且变化小 ;有林地的散布与毗邻指数在 1991～ 2 0 0 1年间整体加大 ,其中黑松与落叶松分别增大到 73.5 1、76 .4 8,说明分布呈零散分布的趋势 ;(4 )景观格局的分布中 ,类斑的分布与坡度呈正态分布 ;类斑与坡向没有较大关系 ,分布较均匀 ;类斑集中分布在 2 0 1～ 80 0m的高程区 ,类斑块数与多样性在 4 0 1～ 6 0 0m达到最高值。

数字经济赋能农业农村现代化:理论机制与实证检验

实现农业农村现代化是乡村全面振兴的必由之路,数字经济为实现农业农村现代化提供了新动能。文章从产业现代化、生态优良化、文化现代化、治理有效化和生活富裕化五个维度构建农业农村现代化水平评价指标体系,深入分析数字经济赋能农业农村现代化发展的理论机制,并基于2011—2020年我国30个省份的面板数据对数字经济赋能农业农村现代化的作用机制进行实证检验。研究发现:(1)数字经济能够促进农业农村现代化发展。(2)在作用机制上,数字经济通过促进产业现代化、生态优良化、文化现代化、治理有效化和生活富裕化来驱动农业农村现代化发展,且对五个维度的促进作用有异质性,其中数字经济对产业现代化的影响程度最为强劲,对文化现代化、生活富裕化、治理有效化的影响程度依次减弱,对生态优良化的影响程度最弱。(3)数字经济对农业农村现代化发展的正向促进作用具有区域异质性,对中部地区的正向促进作用最大,其次是西部地区和东部地区,对东北地区的正向促进作用最小。

Cross-scale characteristics of backfill material using NMR and fractal theory

This paper analyzed the pore structure, quantified the pore fractal dimension, calculated the grading index(GI) of mixed aggregate, and studied the relationship among GI, pore structure, and strength to describe the cross-scale characteristics of backfill, which is made from stone powder and cemented tailing. A series of experiments were conducted on stone powder cement tailings backfill(SPCTB). The GI formulas for mixed aggregates, containing stone powder and tailings, were derived based on the Füller theory. The nuclear magnetic resonance(NMR) fractal dimensions of backfills were derived using fractal geometry principles. Compared to the mesopore and macropore fractal dimensions, the correlation between micropore fractal dimension and macro-properties in terms of NMR porosity, pore structure complexity, uniaxial compression strength(UCS), and GI is the most significant. Macropore fractal dimension is generally correlated with UCS and GI and the other properties such as the shape of mixed aggregates also have an impact on fractal dimension. However, mesopore fractal dimension has no obvious relationship with macro-properties. Finally, the relationship between GI and UCS was studied, which contributed to improving backfill’s strength and optimizing gradation.

Relationship Between Changes of River-lake Networks and Water Levels in Typical Regions of Taihu Lake Basin,China

The typical regions of the Taihu Lake Basin,China,were selected to analyze the variation characteristics of river-lake networks under intensive human activities.The characteristics of the fractal dimension of river networks and lakes for different periods were investigated and the influences of river system evolution on water level changes were further explored through the comparison of their fractal characters.The results are as follows:1) River network development of the study area is becoming more monotonous and more simple;the number of lakes is reducing significantly,and the water surface ratio has dropped significantly since the 1980s.2) The box dimension of the river networks in all the cities of the study area decreased slowly from the 1960s to the 1980s,while the decrease was significant from the 1980s to the 2000s.The variations of lake correlation dimension are similar to those of the river network box dimensions.This is unfavorable for the storage capacity of the river networks and lakes.3) The Hurst exponents of water levels were all between 0.5 and 1.0 from the 1960s to the 1980s,while decreased in the 2000s,indicating the decline in persistence and increase in the complexity of water level series.The paper draws a conclusion that the relationship between the fractal dimension of river-lake networks and the Hurst exponents of the water level series can reveal the impacts of river system changes on flood disasters to some extent:the disappearance of river networks and lakes will increase the possibility of flood occurrence.

New Eigenmodes of Propagation in Quadratic Graded Index Media and Complex Fractional Fourier Transform

By introducing a convenient complex form of the α-th 2-dimensional fractional Fourier transform (CFFT) operation we find that it possesses new eigenmodes which are two-mode Hermite polynomials. We prove the eigenvalues of propagation in quadratic graded-index medium over a definite distance are the same as the eigenvalues of the α-th CFFT, which means that our definition of the α-th CFFT is physically meaningful.

3D-QSAR and action mechanism of potential dual inhibitors towards AP-1 and NF-κB

Three-dimensional quantitative structure-activity relationship （3D-QSAR） and docking studies of a series of novel dioxopyrrolinyl-amino-pyrimidine derivatives, which are potential dual inhibitors mediating a transcriptional activation towards protein-1 （AP-1） and nuclear factor kappa B （NF-κB）, have been carried out. The QS, AR models established by comparative molecular field analysis （CoMFA） and comparative molecular similarity index analysis （CoMSIA） show a good predictive ability with cross-validated coefficients q2 of 0.644 and 0.636, respectively. The docking result shows that there are quite lower average values of the flexible and rigid energy scores on the selected binding sites, meanwhile, it further shows that the binding sites just fall on the joint regions between AP-1 （and NF-κB） and DNA. The reason that these analogues have inhibition function towards AP-I and NF-κB is that their existence on these joint regions can effectively prevent free AP-I and NF-κB from binding to DNA. These results can offer a valuable theoretical reference to the pharmaceutical molecular design as well as the action mechanism analysis.

A method for choice of optimum scale on land use monitoring in Tarim River Basin

Optimal scale is one of the important issues in ecology and geography.Based on land-use data of the Tarim River Basin in Xinjiang of China in the 1950s,regarding the area of land use types as the parameter in scale selecting,the histograms of the patches in area are charted.Then,by reinforcing the normalized scale variances(NSV) with 3 landscape indi-ces,the scale characteristics of land use in the Tarim River Basin can be summarized.(1) NSV in the Tarim River up to a maximum at scale of 1:50,000 which is considered appropriate for the Tarim River.(2) Diversity indices of saline land are consistent with NSV's.Diversity indices and NSV of sandy land showed that the appropriate scale is in the same scale domain.There is a significant difference between diversity indices and NSV of forestland and shrub-land.(3) Fractal dimension of sandy land and saline land showed a hierarchical structure at a scale of 1:10,000.Fractal dimension of forestland and shrubland are distributed under the same hierarchical structure in the region.

3D-QSAR and docking studies on 2-arylbenzoxazole and linker-Y transthyretin amyloidogenesis inhibitors

Transthyretin(TTR),a plasma protein with a tetramer structure,could form amyloid fibril associated with several human diseases through the dissociation of tetramer and the misfolding of monomer.These amyloidogenesis can be inhibited by small molecules which bind to the central channel of TTR.A number of small molecules like 2-arylbenzoxazoles(ABZ)analogues are proposed as promising therapeutic strategy to treat amyloidosis.In this work,comparative molecular field analysis(CoMFA)and comparative molecular similarity indices analysis(CoMSIA)three-dimensional quantitative structure-activity relationship(3D-QSAR)and docking studies were performed on series of 2-arylbenzoxazoles(ABZ)and linker-Y analogues to investigate the inhibitory activities of TTR amyloidogenesis at atomic level.Significant correlation coefficients for ABZ series(CoMFA,r2=0.877,q2=0.431;CoMSIA,r2=0.836,q2=0.447)and those for linker-Y series(CoMFA,r2=0.828,q2=0.522;CoMSIA,r2=0.800,q2=0.493)were obtained,and the generated models were validated using test sets.In addition,docking studies on 6 compounds binding to TTR were performed to analyze the forward or reverse binding mode and interactions between molecules and TTR.These results from 3D-QSAR and docking studies have great significance for designing novel TTR amyloidogenesis inhibitors in the future.

Analytical Approximate Solution of Schr?dinger Equation in D Dimensions with Quadratic Exponential-Type Potential for Arbitrary l-State

We present the bound state solution of Schr6dinger equation in D dimensions for quadratic exponential-type potential for arbitrary l-state. We use generalized parametric Nikiforov-Uvarov method to obtain the energy levels and the corresponding eigenfunction in dosed form. We also compute the energy eigenvalues numerically.