中国区域投入产出效率的综合测度与时空格局   总被引：1，自引：1，他引：0  

宋周莺  康蕾  刘毅 《地理研究》2019,38(2):326-336

改革开放40多年来,中国经济发展与资源环境之间的矛盾日益突出,资源环境安全面临严峻的挑战。在此背景下,基于要素投入和经济、环境总产出的综合视角,构建区域投入产出效率评价指标体系,应用数据包络分析方法,采用CCR模型、Super-CCR模型,测算1995-2015年间不同时期中国各省区市的投入产出效率,并对其变化趋势及空间分异进行分析。结果表明,全国投入产出效率在波动中呈上升态势,特别是2010年之后投入产出效率提升较明显;2015年,中国区域投入产出效率呈较明显的由东向西、由北向南逐渐降低的空间格局分异。分区域看,东部地区投入产出效率相对最高,其中北京、天津、广东等省市的上升态势明显;东北地区投入产出效率整体偏低,特别是黑龙江的投入产出效率表现为持续下降;中部各省投入产出效率普遍不高,但河南相对较高且2010年较之前提升明显;西部地区投入产出效率的省际差异明显,其中西南各省投入产出效率下降态势较明显。  相似文献   

航空矢量重力测量水平分量向下延拓的输入输出法     

周波阳  崔家武  张兴福 《大地测量与地球动力学》2018,38(9):903-907

研究航空矢量重力水平分量向下延拓的输入输出法,并以EGM2008计算的东向分量为例进行仿真实验,在不同的噪声水平下对比分析单输入单输出法和双输入单输出法的向下延拓效果。实验结果表明,当东向分量的精度为1.5 mGal时,单输入单输出法和双输入单输出法均能实现稳定向下延拓;当东向分量的精度为6 mGal时,单输入单输出法的延拓效果不可靠,而双输入单输出法能实现稳定向下延拓。  相似文献   

Robust H∞ control for aseismic structures With uncertainties in model parameters     

Song Gang  Lin Jiahao  Zhao Yan  W.Paul Howson  Fred W Williams 《地震工程与工程振动(英文版)》2007,6(4)

This paper presents a robust H∞ output feedback control approach for structural systems with uncertainties in model parameters by using available acceleration measurements and proposes conditions for the existence of such a robust ontput feedback controller.The uncertainties of structural stiffness,damping and mass parameters are assumed to be norm-bounded.The proposed control approach is formulated within the framework of linear matrix inequalities,for which existing convex optimization techniques,such as the LMI toolbox in MATLAB,can be used effectively and conveniently.To illustrate the effectiveness of the proposed robust H∞ strategy,a six-story building was subjected both to the 1940 El Centro earthquake record and to a suddenly applied Kanai-Tajimi filtered white noise random excitation.The results show that the proposed robust H∞ controller provides satisfactory results with or without variation of the structural stiffness,damping and mass parameters.  相似文献   

New formulae for estimating lava flow volumes at Mt. Etna Volcano, Sicily     

J. B. Murray  N. F. Stevens 《Bulletin of Volcanology》2000,61(8):515-526

 A new data set of Etna lava flows erupted since 1868 has been compiled from eight topographic maps of the volcano published at intervals since then. Volumes of 59 flows or groups of flows were measured from topographic difference maps. Most of these volumes are likely to be considerably more accurate than those published previously. We cut the number of flow volumes down to 25 by selecting those examples for which the volume of an individual eruption could be derived with the highest accuracy. This refined data set was searched for high correlations between flow volume and more directly measurable parameters. Only two parameters showed a correlation coefficient of 70% or greater: planimetric flow area A (70%) and duration of the eruption D (79%). If only short duration (<18 days) flows were used, flow length cubed, L³, had a correlation coefficient of 98%. Using combinations of measured parameters, much more significant correlations with volume were found. Dh had a correlation coefficient of 90% (h is the hydrostatic head of magma above the vent), and  , 92% (where W is mean width and E is the degree of topographic enclosure), and a combination of the two , 97%. These latter formulae were used to derive volumes of all eruptions back to 1868 to compare with those from the complete data set. Values determined from the formulae were, on average, lower by 16% (Dh), 7% (, and 19% . Received: 30 November 1998 / Accepted: 20 June 1999  相似文献   

光纤传感腐蚀监测研究     

董飒英  刘云峰  王洪仁 《海洋科学》2005,29(7):94-96

通过化学、物理的方法用金属敏感膜取代光纤的原始包层监测海洋环境中金属结构物的腐蚀状况。通过腐蚀前后光功率的变化表征腐蚀的发生和发展。  相似文献   

输入非线性方程误差自回归系统的多新息辨识方法     

丁锋  毛亚文 《南京气象学院学报》2015,7(1):1-23

典型块结构非线性系统包括基本的输入非线性系统、输出非线性系统、输入输出非线性系统、反馈非线性系统等.输入非线性系统包括输入非线性方程误差类系统和输入非线性输出误差类系统.以输入非线性方程误差自回归系统,即输入非线性受控自回归自回归(IN-CARAR)系统为例,分别基于过参数化模型,基于关键项分离原理,基于数据滤波技术以及基于辨识模型分解技术,研究和提出了IN-CARAR系统的随机梯度辨识方法、多新息随机梯度辨识方法、递推最小二乘辨识方法、多新息最小二乘辨识方法.这些方法可以推广到其他输入非线性方程误差系统、输入非线性输出误差类系统、输出非线性方程误差类系统、输出非线性输出类系统、反馈非线性系统等.同时,给出了几个典型辨识算法的计算步骤、流程图和计算量.  相似文献   

系统辨识(4)：辅助模型辨识思想与方法     

丁锋 《南京气象学院学报》2011,(4):289-318

辅助模型辨识思想、多新息辨识理论、递阶辨识原理、耦合辨识概念是该文作者提出的研究辨识问题的原创性新方法,已经被用在很多辨识问题的研究中,形成了不同的辨识方法族,可以用于解决许多线性或非线性模型的自适应信号处理、自适应参数估计、自适应滤波和预测、自适应控制等问题.由于客观事物具有双重属性:一些特征变量是可观测的;一些是不可测的.如果表征系统特征的观测变量都是可测的,就容易建立描述其运动规律的数学模型.客观事物的不可测属性给建立系统数学模型带来特别的困难.在这种情况下,如何利用系统的可测信息,实现对系统未知变量的估算,来建立系统的数学模型,是辨识领域极具挑战性的研究课题.辅助模型辨识思想就是在这样的背景下发展起来的.该文介绍辅助模型辨识思想和一些基于辅助模型的辨识方法.  相似文献   

豫南一季中稻生育期气象因子与产量及其构成要素相关性分析   总被引：1，自引：0，他引：1  

赵辉  吴骞 《气象与环境科学》2011,34(4):68-71

以信阳国家一级农业气象试验站1981-2009年29a气象资料以及水稻观测资料为基础,利用SPSS统计分析软件．建立豫南一季中稻生育期旬平均气温、最低气温、降水量以及日照时数与空壳率、枇各率、千粒重以及地段1m2产量之闻的统计回归关系。结果表明：1）一季中稻的空壳率随着6月中旬和8月中旬的日照时数的减少而增大,随着8月...  相似文献   

Can U.S. multi-state climate mitigation agreements work? A perspective from embedded emission flows     

《Global Environmental Change》2022

Subnational and non-governmental actors are expected to provide important contributions to broader climate actions. A consistent and accurate quantification of their GHG emissions is an important prerequisite for the success of such efforts. However, emissions embodied in domestic and international supply chains, that can undermine the effectiveness of climate agreements, add challenges to the quantification of emissions originating from the consumption of goods and services produced elsewhere. We examine emission transfers between the states that have joined the U.S. Climate Alliance (USCA) and others. Our results show that states pledging to curb emissions consistent with the Paris Agreement were responsible for approximately 40% of total U.S. territorial GHG emissions. However, when accounting for transferred emissions through international and interstate supply chains of the products they consume, the share of Alliance states increased to 52.4% of the national total GHG emissions. The consumption-based emissions for some Alliance states, such as Massachusetts and New York, could be more than 1.5 times higher than their production-based emissions. Our detailed sectoral analysis highlights the challenges facing such agreements to extend cooperation in the future for larger joint benefit given the potential for carbon leakage from member states implementing stricter environmental policies that could lead to higher emissions from non-member states. It is critical for these arrangements to pay close attention to transferred emissions.  相似文献   

中国城市土地绿色利用效率驱动因素及空间分异   总被引：1，自引：0，他引：1  

卢新海  李佳  刘超  匡兵  蔡大伟  侯娇 《地理科学》2022,42(4):611-621

以2009—2018年中国285个地级及以上城市为研究对象,测算各城市的城市土地绿色利用效率,对其驱动因素的空间异质性进行探究与分区。结果表明：① 城市土地绿色利用效率总体呈波动上升趋势,集聚特征显著,省际、省内差异明显;区域上,呈现西部＞东部＞中部的格局;规模等级上,随着城市规模等级降低而递增。② 城市土地绿色利用效率是众多因素交互驱动的结果,且各驱动因素均具有明显的空间异质性特征,呈现出空间带状或片状分布规律。③ 根据城市土地绿色利用效率驱动因素的空间异质性特征,可划分为产业结构高级化、环境规制和科技投入水平主导的东南地区;生态资源禀赋主导的华北地区;经济发展水平、城市空间集聚主导的西南地区;土地市场化主导的西北地区;人口集聚、土地财政、基础设施水平主导的东北地区。未来应因城施策、因地制宜,采取差异化的措施来提升城市土地绿色利用效率。  相似文献