中国城市群经济增长质量与数量协调关系的时空演化与机理     

张国俊  王运喆  王珏晗  曹永旺  周春山 《地理科学》2021,41(12):2075-2086

以中国“十三五”规划纲要提及的19个城市群为研究对象,分别从经济效率、经济结构、经济稳定性、经济发展潜力、成果分配、资源环境、民生福利7个维度刻画城市群经济增长质量,从GDP增长率和人均GDP两个维度刻画经济增长数量以构建综合指标体系,运用熵值法、耦合协调模型、地理探测器等方法,剖析2006—2018年中国城市群经济增长质量与数量的耦合协调关系及其相互作用机理,研究结果表明：① 总体协调水平上,中国城市群经济增长质量与数量的协调度较低,且呈下降趋势;② 协调度空间格局上,经济增长质量与增长数量、增长速度的空间格局呈现“东高西低”的趋势,且保持相对稳定,但经济增长质量与增长规模的协调度空间格局差异较大;③ 协调类型上,“数量滞后”型呈零星分布,“规模滞后”型向中西部集聚,“速度滞后”型向东北拓展,“质量滞后”型表现出多样性特征;④ 经济增长质量与规模、速度的协调关系表现出不一致的特征;⑤ 相互协调机理分析发现,民生福利、经济发展潜力、人均GDP对中国城市群经济增长质量与数量协调水平的提升具有显著影响。⑥ 针对不同协调类型的城市群应分别采取相应举措以助力中国城市群经济高质量发展。  相似文献   

西藏雅鲁藏布江流域典型沙漠区生态修复植物群落物种多样性     

常学向  陈怀顺  李志刚  张红萍 《中国沙漠》2021,41(6):187-194

为了深入了解和探讨西藏沙化土地治理区的植物群落的结构类型、组织水平和稳定程度,根据西藏雅鲁藏布江河谷沙地山南市全国防沙治沙综合示范区20个样地的调查资料,分析了西藏山南市全国防沙治沙综合示范区植物群落物种多样性特征。结果表明：西藏山南市全国防沙治沙综合示范区的植物有34种,藏沙蒿（Artemisia wellbyi）、花棒（Hedysarum scoparium）、桑（Morus alba）、沙打旺（Astragalus adsurgens）和沙蒿（Artemisia desertorum）占优势地位。综合示范区固沙植被平均盖度为31.6%±13.1%;平均生长高度为41.2±19.9 cm;平均生长密度为4.6±4.7株·m^-2。植物群落物种多样性H指数平均为0.99±0.54;物种多样性D指数平均为2.55±1.37;物种均匀度平均为1.76±0.75。  相似文献   

长三角地区城市创新投入要素的经济溢出效应及趋同格局   总被引：2，自引：2，他引：0  

孙彪  杨山 《地理科学进展》2021,40(1):147-160

近年来,城市创新投入要素在长三角一体化进程中的作用不断增加。论文基于2010—2017年长三角地区各城市空间面板数据,利用空间计量模型与马尔可夫链等方法,测度创新投入要素的经济溢出效应并揭示长三角一体化背景下创新外溢对区域经济趋同格局的影响。结果表明：① 长三角地区城市创新投入和创新产出均对城市自身经济增长表现出显著的直接效应,创新投入的溢出效应显著且大于其直接效应,而创新产出的溢出效应不显著;② 受创新投入要素影响,长三角地区经济增长存在“俱乐部趋同”现象,但毗邻不同创新投入类型的城市对本地经济增长呈现出“高促进、低抑制”的态势;③ 长三角一体化经济格局呈现由中心区高水平趋同向外围低水平趋同转变的特征,且具有明显的空间转移惰性,创新投入外溢作用将加剧区域经济增长的“马太效应”;④ 经济增长类型转移的城市集中于省域边界,在局部溢出作用下表现出复杂的转移机理。基于创新局部外溢促进经济俱乐部趋同的分析结果,对长三角区域一体化发展提出针对性建议。  相似文献   

基于空间句法耦合SLEUTH模型的新老城区扩展模拟研究——以开封市为例     

张宸铭  高尚  何贝  高建华 《地理研究》2021,40(5):1372-1386

在快速城镇化背景下,历史文化名城常扩建新区并形成新老城区联动发展格局,新建城区以“飞地”形式扩张,不易被传统的元胞自动机方法准确模拟。空间句法是基于空间拓扑的整体性交通网络研究方法,其自上而下的建模策略与元胞自动机自下而上的邻域转换规则起到了互补,两种模型相结合提供了解决上述问题的途径。本文在验证交通土地空间关联的基础上,将句法变量融入SLEUTH模型的排除图层,对开封城市扩张进行了综合模拟。研究结果表明：① 交通增量与用地扩张具有显著的正相关,其关联度随研究单元粒度的扩大而提升。② 在城市从飞地新区扩建到后续填补开发的过程中,与用地扩张关联最高的交通类型由穿行性交通转向到达性交通,且遍历全局的计算结果方位指向性特征更加明显,遍历局部的计算结果片区集聚性特征更加明显。③ 将空间句法与SLEUTH模型松散耦合,可以有效捕捉飞地型城市新增团块,开封市中心城区空间扩张类型可被解读为老城区边缘型增长和新城区飞地型增长并存的模式。④ 空间句法模型不仅能够反演城市交通流,而且对城市产业布局、规划现状与演化轨迹具有间接指向性,这对城市增长模拟十分重要。  相似文献   

Architecture,deformation style and petrophysical properties of growth fault systems: the Late Triassic deltaic succession of southern Edgeøya (East Svalbard)     

《Basin Research》2018,30(5):1042-1073

The Late Triassic outcrops on southern Edgeøya, East Svalbard, allow a multiscale study of syn‐sedimentary listric growth faults located in the prodelta region of a regional prograding system. At least three hierarchical orders of growth faults have been recognized, each showing different deformation mechanisms, styles and stratigraphic locations of the associated detachment interval. The faults, characterized by mutually influencing deformation envelopes over space‐time, generally show SW‐ to SE‐dipping directions, indicating a counter‐regional trend with respect to the inferred W‐NW directed progradation of the associated delta system. The down‐dip movement is accommodated by polyphase deformation, with the different fault architectural elements recording a time‐dependent transition from fluidal‐hydroplastic to ductile‐brittle deformation, which is also conceptually scale‐dependent, from the smaller‐ (3rd order) to the larger‐scale (1st order) end‐member faults respectively. A shift from distributed strain to strain localization towards the fault cores is observed at the meso to microscale (<1 mm), and in the variation in petrophysical parameters of the litho‐structural facies across and along the fault envelope, with bulk porosity, density, pore size and microcrack intensity varying accordingly to deformation and reworking intensity of inherited structural fabrics. The second‐ and third‐order listric fault nucleation points appear to be located above blind fault tip‐related monoclines involving cemented organic shales. Close to planar, through‐going, first‐order faults cut across this boundary, eventually connecting with other favourable lower‐hierarchy fault to create seismic‐scale fault zones similar to those imaged in the nearby offshore areas. The inferred large‐scale driving mechanisms for the first‐order faults are related to the combined effect of tectonic reactivation of deeper Palaeozoic structures in a far field stress regime due to the Uralide orogeny, and differential compaction associated with increased sand sedimentary input in a fine‐grained, water‐saturated, low‐accommodation, prodeltaic depositional environment. In synergy to this large‐scale picture, small‐scale causative factors favouring second‐ and third‐order faulting seem to be related to mechanical‐rheological instabilities related to localized shallow diagenesis and liquidization fronts.  相似文献   

Age, growth and reproduction of the sand smelt Atherina boyeri Risso, 1810 in the Gomishan wetland – southeast Caspian Sea     

Rahman Patimar  Morteza Yousefi  Seyyed Morteza Hosieni 《Estuarine, Coastal and Shelf Science》2009,81(4):457-462

A total of 2256 specimens of Atherina boyeri caught in Gomishan wetland (a marsh lagoon located at the southeast Caspian Sea) during spawning season from February to August 2007 were examined for life-history attributes. The population has a 4-year life cycle. Length–weight relationship was estimated as W = 0.0053TL^3.0181 for males and W = 0.0050TL^3.063 for females, being allometrically positive for both sexes. The von Bertalanffy growth function fitted to back-calculated size at age data was: Lt = 155.17[1 − exp − 0.28(t + 0.738)] and Lt = 162.77[1 − exp − 0.27(t + 0.727)] for males and females respectively. The sex ratio was 1:1.30 in favor of females. The reproductive season, evaluated from GSI, extended from March to July, with a peak in March. The average absolute and relative fecundities were 2976 eggs and 874 eggs g⁻¹ of body weight respectively. The diameter of oocytes ranged from 0.03 to 0.20 mm with a mean value of 0.68. The life-history patterns of A. boyeri in the population under study imply that the population of this species in the southeast Caspian Sea differs markedly from those of other localities of its range distribution. The differences were thought to be due to differences in geographical locations.  相似文献   

Influence of combined changes in salinity and copper modulation on growth and copper uptake in the tropical green macroalga Ulva reticulata     

Florence Mamboya  Thomas J. Lyimo  Tommy Landberg  Mats Bjrk 《Estuarine, Coastal and Shelf Science》2009,84(3):326-330

The influence of salinity on growth and Cu uptake in the green macroalga Ulva reticulata collected from the intertidal area in the Western Indian Ocean was studied under controlled laboratory conditions. Exposure concentrations ranged from 5 to 500 μg Cu l⁻¹ at five salinities (ranging 20–40). The accumulation of Cu increased with decreasing salinity, so that the uptake at 500 μg Cu l⁻¹ was approximately 2.7, 2.4 and 2.0 times higher at salinities of 20, 25, and 30 respectively, than uptake at salinity of 35, and with uptake being lowest at salinity of 40. Ulva maintained a positive growth rate over the whole salinity range (20–40), with highest rates at salinity of 35. When exposing to Cu at low salinities (20 and 25), the growth rate of Ulva was strongly inhibited suggesting an increase in toxicity of Cu with decreasing salinity. EC50 and NOEC increased with increase in salinity, implying a reduced Cu toxicity at high salinities. It was concluded that salinity needs to be considered when using macroalgae, such as U. reticulata, as a bioindicator of heavy metals in areas with heavy rainfall, underground fresh water intrusion or in estuaries, as they might accumulate more metals and be more negatively affected.  相似文献   

人工养殖条件下达氏鳇杂交种幼鱼生长特性的初步研究   总被引：6，自引：0，他引：6  

石振广  董双林  鲁宏申  王云山  李文龙 《中国海洋大学学报(自然科学版)》2008,38(1):33-38

为了解在人工养殖条件下达氏鳇(Huso dauricus)杂交种(达氏鳇♂×天然杂交种♀(达氏鳇♀×史氏鲟♂) )的生长特性,在水温11～22 ℃时,对达氏鳇杂交种体长和体重的生长进行实验研究.应用计算机软件Excel和SPSS对测量的数据进行处理分析,结果表明:平均全长为33.32 cm、平均体重为145.83 g的139日龄幼鱼经75 d的人工饲养长成平均全长为48.79 cm、平均体重为437.36 g的个体,全长与日龄之间呈线性关系L=3.292 7t 30.517,R2=0.959 4,其全长日均增长量为2.06 mm、平均瞬时增长率为 0.076 3,体重与日龄呈指数函数关系,Wgc=119.74e0.234 6t,R2=0.956;体重日均增长量为3.887 1 g、平均瞬时生长率为0.219 7;体重与全长的回归曲线为WwL=0.005 6L2.892 9,R2=0.998 2,幂指数接近于3,表明该鱼体重与全长的立方呈正相关系,属于等比生长类型.  相似文献   

Effects of basic fibroblast growth factor and insulin-like growth factor on cultured cartilage cells from skate Raja porasa     

Fan Tingjun  Jin Lingyun  Wang Xiaofeng 《中国海洋湖沼学报》2003,21(4):305-311

Effects of basic fibroblast growth factor (bFGF) and insulin-like growth factor II (IGF-II) on cartilage cells from proboscis of skate,Raja porasa Günther, were investigated in this study. The cartilage cells were cultured in 20% FBS-supplemented MEM medium at 24°C. Twelve hours after culture initiation, the cartilage cells were treated with bFGF and IGF-II at different concentration combinations. It was found that 20 ng/ml of bFGF or 80 ng/ml of IGF-II was enough to have obvious stimulating effect on the growth and division of skate cartilage cells. Test of bFGF and IGF-II together, revealed that 20 ng/ml of bFGF and 80 ng/ml of IGF-II together had the best stimulating effect on the growth and division of skate cartilage cells. The cartilage cells cultured could form a monolayer at day 7. This work was partially supported and funded by the China Education Committee as the “Imbursement Project for Studied Abroad Returnees”.  相似文献   

外商直接投资与经济增长的关系研究——基于分省和分区数据的检验   总被引：1，自引：0，他引：1  

杨柳勇  陈立慧  楼惠新 《地球信息科学学报》2008,10(3):350-356

论文分别以分省和分区（东、中、西部）1992～2004年的面板数据,利用我们修正过的De Mello模型和更为稳健的模型检验方法,研究了我国利用外商直接投资对经济增长的影响作用。研究结果发现,利用分省数据的模型证明了FDI对我国经济增长的正向积极作用,这一点与其他研究结果相同,但是利用分区数据的研究表明,虽然我国西部仍然是FDI作用最弱的区域,但是东部与中部比较,GDP增长率变动对FDI增长率变动的敏感性不明显,有别于中部,这在一定程度上可以说明东部地区存在FDI过密和外商投资产业的过度竞争问题。  相似文献