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基于Udwadia-Kalaba方法的Delta机器人动力学建模及轨迹跟踪控制
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作者 杨磊 李钦生 张国政 《兰州文理学院学报(自然科学版)》 2025年第4期56-63,共8页
针对Delta机器人的动力学建模问题,提出了一种结合Udwadia-Kalaba(U-K)方法与Lagrange方程建立动力学模型的方法.首先,利用Lagrange方程得到无约束的系统,采用运动学约束来描述系统间的物理连接;然后,通过U-K方法获得约束力的解析解,并... 针对Delta机器人的动力学建模问题,提出了一种结合Udwadia-Kalaba(U-K)方法与Lagrange方程建立动力学模型的方法.首先,利用Lagrange方程得到无约束的系统,采用运动学约束来描述系统间的物理连接;然后,通过U-K方法获得约束力的解析解,并将约束力施加到无约束系统;最后,通过Pfaffian标准微分形式和U-K方法计算得到Delta机器人的动力学模型.在设计轨迹跟踪控制器时,将目标轨迹视为虚拟约束,并运用U-K方法确定输出力和力矩,以便符合轨迹的约束条件.应用数值仿真验证了该建模方法与轨迹跟踪的有效性. 展开更多
关键词 Udwadia-Kalaba方法 delta机器人 动力学建模 约束 轨迹跟踪
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连续时间Sigma-Delta调制器的建模和低功耗设计
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作者 卢丛远 卜刚 《舰船电子工程》 2025年第4期91-96,共6页
连续时间Sigma-Delta调制器克服了离散时间Sigma-Delta调制器速度的限制,在宽带通信领域受到了广泛关注。此外,连续时间Sigma-Delta调制器也为中低带宽高精度ADC的低功耗设计提供了可能的选择方案。论文首先通过非理想参数Simulink建模... 连续时间Sigma-Delta调制器克服了离散时间Sigma-Delta调制器速度的限制,在宽带通信领域受到了广泛关注。此外,连续时间Sigma-Delta调制器也为中低带宽高精度ADC的低功耗设计提供了可能的选择方案。论文首先通过非理想参数Simulink建模分析,得到在给定精度要求的情况下的连续时间三阶Sigma-Delta调制器各个电路组成模块的最低指标;之后,基于SMIC 0.18μm CMOS工艺,在1.8 V电源电压下,对电路进行了晶体管级设计。结果显示,在1 MHz带宽下,调制器输出信号的带内信噪比为76.2 dB,总功耗为3 mW。 展开更多
关键词 CT Sigma-delta调制器 SIMULINK建模 低功耗设计
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Flow Behavior and Constitutive Modeling of Delta-processed Inconel 718 alloy 被引量:3
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作者 Jia-yong SI Xiao-hang LIAO +1 位作者 Li-qiang XIE Kai-rui LIN 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2015年第9期837-845,共9页
The flow behavior of delta-processed Inconel 718 was studied in temperature range of 900-1 060℃ and strain rate range of 0.001-0.5s-1.The effects of friction and temperature on the compressive deformation behavior we... The flow behavior of delta-processed Inconel 718 was studied in temperature range of 900-1 060℃ and strain rate range of 0.001-0.5s-1.The effects of friction and temperature on the compressive deformation behavior were investigated,and the flow stress-strain error caused by friction was revised.The results showed that the effect of the friction was obvious with increasing strain rate and decreasing deformation temperature.The revised flow stress is decreased by increasing temperature and decreasing strain rate and exhibits a typical dynamic recrystallization behavior.The constitutive model has been developed through a hyperbolic-sine Arrhenius type equation to relate the flow stress,strain rate and temperature.The influence of strain has also been incorporated by considering the variation of material constants as a function of strain.The prediction accuracy of developed constitutive model has been assessed using standard statistical formulae.According to the analysis results,the proposed deformation constitutive equation gives an accurate and precise estimate of flow stress of delta-processed Inconel 718 alloy. 展开更多
关键词 Inconel 718 delta process flow behavior constitutive modeling
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Sedimentary facies and depositional model of shallow water delta dominated by fluvial for Chang 8 oil-bearing group of Yanchang Formation in southwestern Ordos Basin,China 被引量:12
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作者 陈林 陆永潮 +5 位作者 吴吉元 邢凤存 刘璐 马义权 饶丹 彭丽 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第12期4749-4763,共15页
A systematic analysis of southwestern Ordos Basin's sedimentary characteristics,internal architectural element association styles and depositional model was illustrated through core statistics,well logging data an... A systematic analysis of southwestern Ordos Basin's sedimentary characteristics,internal architectural element association styles and depositional model was illustrated through core statistics,well logging data and outcrop observations in Chang 8 oil-bearing group.This analysis indicates that shallow water delta sediments dominated by a fluvial system is the primary sedimentary system of the Chang 8 oil-bearing group of the Yanchang Formation in southwestern Ordos Basin.Four microfacies with fine grain sizes are identified: distributary channels,sheet sandstone,mouth bar and interdistributary fines.According to the sandbody's spatial distribution and internal architecture,two types of sandbody architectural element associations are identified: amalgamated distributary channels and thin-layer lobate sandstone.In this sedimentary system,net-like distributary channels at the delta with a narrow ribbon shape compose the skeleton of the sandbody that extends further into the delta front and shades into contiguous lobate distribution sheet sandstone in the distal delta front.The mouth bar is largely absent in this system.By analyzing the palaeogeomorphology,the palaeostructure background,sedimentary characteristics,sedimentary facies types and spatial distribution of sedimentary facies during the Chang 8 period,a distinctive depositional model of the Chang 8 shallow water fluvial-dominated delta was established,which primarily consists of straight multi-phase amalgamated distributary channels in the delta plain,net-like distributary channels frequently diverting and converging in the proximal delta front,sheet sandstones with dispersing contiguous lobate shapes in the distal delta front,and prodelta or shallow lake mudstones. 展开更多
关键词 sedimentary facies architectural element DEPOSITIONAL model shallow water delta CHANG 8 oil-bearing GROUP ORDOS Basin
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Formation Conditions and Sedimentary Model of Over-Flooding Lake Deltas within Continental Lake Basins: An Example from the Paleogene in the Jiyang Subbasin, Bohai Bay Basin 被引量:3
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作者 WANG Jian CAO Yingchang +1 位作者 LIU Huimin GAO Yongjin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2015年第1期270-284,共15页
A large quantity of drilling core, paleontology, geochemistry and geophysics data revealed several features of the Jiyang subbasin during the deposition of the Ekl-ES4x members: (1) the paleotopography of the gentl... A large quantity of drilling core, paleontology, geochemistry and geophysics data revealed several features of the Jiyang subbasin during the deposition of the Ekl-ES4x members: (1) the paleotopography of the gentle slope belt had an extremely low gradient; (2) the paleoclimate frequently alternated between dry and wet periods in a generally arid setting; (3) there was strong weathering around the periphery of the basin; (4) the lake was very shallow; (5) the lake level frequently rose and fell; and (6) the sedimentary environment of the gentle slope belt was an over- flooding lake. All of these factors provided favorable geological conditions for the development of an over-flooding lake delta. The lithologies of the continental over-flooding lake delta deposits are complex and diverse. The compositional maturity is moderate to low, and the grain size distribution curves and sedimentary structures indicate the presence of both gravity and traction currents. The sedimentary microfacies associations consist of a combination of ordered superposition of flood channels, distributary channels and sheet sands. The delta exhibits a weak foreset seismic reflection. The over-flooding lake delta deposits are laterally extensive. The sandstone content is high, and the individual sandstone beds are thin. The flood channel and distributary channel deposits exhibit evidence of bifurcation and lateral migration. The distribution of the sandbodies and the oxidation color of the mudstones provide evidence of cyclic deposition. The paleoclimate was the dominant factor controlling the development of the over-flooding lake delta. Due to the frequently alternating wet and dry paleoclimates, the over-flooding lake delta is characterized by the development of a broad upper plain and a lower delta plain. The upper delta plain is characterized by flood channel deposits, whereas the lower delta plain is represented by distributary channel deposits. The transition zone is characterized by the interaction of flood channels and distributary channels. Due to fault activity, the sandbodies of the over-flooding lake delta were juxtaposed against hydrocarbon source rocks, which was favorable for the development of lithologic reservoirs or structural-lithologic reservoirs. The lower delta plain deposits comprise the most favorable reservoirs. 展开更多
关键词 Jiyang subbasin continental basin over-flooding lake delta sedimentary model oil andgas exploration
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Discovery and petroleum geological significance of delta in the third member of Oligocene Lingshui Formation in southern Baodao Sag,Qiongdongnan Basin,South China Sea 被引量:1
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作者 PEI Jianxiang LUO Wei +2 位作者 GUO Shiyang LIN Lu LI Keliang 《Petroleum Exploration and Development》 SCIE 2024年第2期337-350,共14页
Based on the 3D seismic data and the analysis and test data of lithology,electricity,thin sections and chronology obtained from drilling of the Qiongdongnan Basin,the characteristics and the quantitative analysis of t... Based on the 3D seismic data and the analysis and test data of lithology,electricity,thin sections and chronology obtained from drilling of the Qiongdongnan Basin,the characteristics and the quantitative analysis of the source-sink system are studied of the third member of the Upper Oligocene Lingshui Formation(Ling 3 Member)in the southern fault step zone of the Baodao Sag.First,the YL10 denudation area of the Ling 3 Member mainly developed two fluvial systems in the east and west,resulting in the formation of two dominant sand transport channels and two delta lobes in southern Baodao Sag,which are generally large in the west and small in the east.The evolution of the delta has experienced four stages:initiation,prosperity,intermittence and rejuvenation.Second,the source-sink coupled quantitative calculation is performed depending on the parameters of the delta sand bodies,including development phases,distribution area,flattening thickness,area of different parent rocks,and sand-forming coefficient,showing that the study area has the material basis for the formation of large-scale reservoir.Third,the drilling reveals that the delta of the Ling 3 Member is dominated by fine sandstone,with total sandstone thickness of 109-138 m,maximum single-layer sandstone thickness of 15.5-30.0 m,and sand-to-strata ratio of 43.7%-73.0%,but the physical properties are different among the fault steps.Fourth,the large delta development model of the small source area in the step fault zone with multi-stage uplift is established.It suggests that the episodic uplift provides sufficient sediments,the fluvial system and watershed area control the scale of the sand body,the multi-step active fault steps dominate the sand body transport channel,and local fault troughs decide the lateral propulsion direction of the sand body.The delta of the Ling 3 Member is coupled with fault blocks to form diverse traps,which are critical exploration targets in southern Baodao Sag. 展开更多
关键词 Qiongdongnan Basin Baodao Sag Oligocene Lingshui Formation delta model source-sink system small source area large-scale reservoirs step fault zone
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Conversion of Object Oriented System into Software Product Line with Delta Modeling Abstract Behavioral Specification
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作者 Ricky Timothy Gultom Maya Retno Ayu Setyautami Iis Solichah 《Journal of Computer and Communications》 2014年第2期85-90,共6页
This article contains a system conversion from object oriented design into Software Product Line (SPL) using delta modeling of Abstract Behavioral Specification (ABS). ABS is a modeling language which targets system w... This article contains a system conversion from object oriented design into Software Product Line (SPL) using delta modeling of Abstract Behavioral Specification (ABS). ABS is a modeling language which targets system with high level of variety and supports SPL development with delta modeling. The case study of this thesis is a digital library system called Library Automation and Digital Archive (LONTAR). Originally, LONTAR only uses SOAP-based web service. With ABS, LONTAR will be converted into SPL and implement another web service called REST. The motivation of this conversion of LONTAR from object oriented into SPL is because it is easier to develop system with ABS than using regular object oriented. Product definition in ABS is relatively easier than creating a new subclass and do customization to make it works well. 展开更多
关键词 System CONVERSION ABSTRACT BEHAVIORAL SPECIFICATION delta modelING Software Product line Object Oriented
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原料性质大幅变化情况下催化重整Delta-Base数据的生成方法
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作者 宋雨雨 吕文进 +2 位作者 崔晨 宋建 周祥 《石油炼制与化工》 CAS CSCD 北大核心 2024年第8期157-163,共7页
针对催化重整原料性质变化幅度较大的情况,提出采用变步长计算结合分子水平机理模型生成装置Delta-Base数据的方法。该方法通过计算原料性质扰动时产品质量分数变化量绝对值随原料性质变化量绝对值的变化率;并将该变化率的值域分成若干... 针对催化重整原料性质变化幅度较大的情况,提出采用变步长计算结合分子水平机理模型生成装置Delta-Base数据的方法。该方法通过计算原料性质扰动时产品质量分数变化量绝对值随原料性质变化量绝对值的变化率;并将该变化率的值域分成若干等份,根据每次计算得到变化率值域的范围不同,选择下一步计算时的变量扰动步长;继而在计算过程中取每次变量扰动的中点值产品质量分数进行验证,从而在提高计算效率的同时保证了计算结果的准确性。结果表明:利用该方法计算得到的各产品质量分数相对误差较小,基本不超过2.5%;对计算数据拟合可得到不同产品质量分数数据拟合方程,通过拟合方程可生成芳烃潜含量变化三阶段Delta-Base数据;比较原料芳烃潜含量(w)为42%时的产品预测结果,发现Delta-Base数据预测值和拟合方程计算值的平均偏差均为0.16%,说明该方法具有很好的准确性,利用分子水平机理模型生成的Delta-Base数据更能反映真实的分子反应历程。 展开更多
关键词 催化重整 分子水平模型 线性规划 delta-Base数据
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Simulating Potential Distribution of Tamarix chinensis in Yellow River Delta by Generalized Additive Models
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作者 SONG Chuangye HUANG Chong LIU Gaohuan 《湿地科学》 CSCD 2010年第4期347-353,共7页
There are typical ecosystems of littoral wetlands in the Yellow River Delta.In order to study the relationships between Tamarix chinensis and environmental variables and to predict T.chinensis potential distribution i... There are typical ecosystems of littoral wetlands in the Yellow River Delta.In order to study the relationships between Tamarix chinensis and environmental variables and to predict T.chinensis potential distribution in the Yellow River Delta,641 vegetation samples and 964 soil samples were collected in the area in October of 2004,2005,2006 and 2007.The contents of soil organic matter,total phosphorus,salt,and soluble potassium were determined.Then,the analyzed data were interpolated into spatial raster data by Kriging interpolation method.Meanwhile,the digital elevation model,soil type map and landform unit map of the Yellow River Delta were also collected.Generalized Additive Models(GAMs) were employed to build species-environment model and then simulate the potential distribution of T.chinensis.The results indicated that the distribution of T.chinensis was mainly limited by soil salt content,total soil phosphorus content,soluble potassium content,soil type,landform unit,and elevation.The distribution probability of T.chinensis was produced with a lookup table generated by Grasp Module(based on GAMs) in software ArcView GIS 3.2.The AUC(Area Under Curve) value of validation and cross-validation of ROC(Receive Operating Characteristic) were both higher than 0.8,which suggested that the established model had a high precision for predicting species distribution. 展开更多
关键词 Yellow River delta Tamarix chinensis Generalized Additive models
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Elaboration of Simplest Folding Structures in 2-Dimensional Lattice with Delta-Hemolysin and Its Variants in HP Model
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作者 Shaomin Yan Guang Wu 《Journal of Biomedical Science and Engineering》 2019年第5期293-309,共17页
Although the advanced 3-dimensional structure measurements provide more and more detailed structures in Protein Data Bank, the simplest 2-dimensional lattice model still looks meaningful because 2-dimensional structur... Although the advanced 3-dimensional structure measurements provide more and more detailed structures in Protein Data Bank, the simplest 2-dimensional lattice model still looks meaningful because 2-dimensional structures play a complementary role with respect to 3-dimensional structures. In this study, the folding structures of delta-hemolysin and its six variants were studied at 2-dimensional lattice, and their amino acid contacts in folding structures were considered according to HP model with the aid of normalized amino acid hydrophobicity index. The results showed that: 1) either delta-hemolysin or each of its variants could find any of its folding structure in one eighth of 1,129,718,145,924 folding structures because of symmetry, which reduces the time required for folding, 2) the impact of pH on folding structures is varying and associated directly with the amino acid sequence itself, 3) the changes in folding structures of variants appeared different case by case, and 4) the assigning of hydrophobicity index to each amino acid was a way to distinguish folding structures at the same native state. This study can help to understand the structure of delta-hemolysin, and such an analysis can shed lights on NP-problem listed in millennium prize because the HP folding in lattice belongs to a sub-problem of NP-problem. 展开更多
关键词 FOLDING Structure delta-Hemolysin HP model HYDROPHOBICITY Index LATTICE Minimal Energy Native State
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基于PLUS-InVEST模型的长三角城市群碳储量时空演变与预测 被引量:7
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作者 王伟武 伏添乐 陈欢 《环境科学》 北大核心 2025年第4期1937-1950,共14页
土地利用变化是影响陆地生态系统碳储量变化的重要因素,研究土地利用变化与碳储量之间关系对优化区域土地利用结构,维持区域碳平衡并提高区域碳储量具有重要意义.在“双碳”目标和区域一体化高质量发展的双重背景之下,长三角地区作为中... 土地利用变化是影响陆地生态系统碳储量变化的重要因素,研究土地利用变化与碳储量之间关系对优化区域土地利用结构,维持区域碳平衡并提高区域碳储量具有重要意义.在“双碳”目标和区域一体化高质量发展的双重背景之下,长三角地区作为中国式现代化建设高地有着重要的战略地位.因此,以长三角城市群为例,基于PLUS模型分析2000~2020年土地利用变化,结合自然发展情景、耕地保护情景和生态优先情景设置,对2030年长三角城市群土地利用格局进行模拟预测,并进一步运用InVEST模型测算2000~2020年及2030年不同情景下长三角城市群碳储量变化.最后,利用空间自相关分析探索长三角城市群不同情景下陆地生态系统碳储量时空变化特征并提出相应建议.结果表明:①2000~2020年长三角城市群的碳储量损失了51.08×10^(6) t.耕地面积的减少(7.82%)以及建设用地面积的增加(7.56%)是碳损耗的主要原因.②2030年长三角城市群陆地生态系统碳储量在自然发展情景、耕地保护情景和生态优先情景下的碳储量分别为2.65×10^(9)、2.67×10^(9)和2.70×10^(9) t.与2020年碳储量值相比,3种情景下的碳储量值均有不同程度下降.③局部空间自相关分析结果显示,3种情景下的碳储量空间分布具相似性,高值区域在长三角城市群南部及西部区域出现集聚,低值区域则在东部、中部区域聚集.研究结果可为长三角城市群未来实现“碳达峰,碳中和”目标提供科学依据. 展开更多
关键词 土地利用变化 碳储量 InVEST模型 PLUS模型 长三角城市群
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城市群旅游生态效率时空演化及影响因素比较研究——以长三角与珠三角城市群为例 被引量:3
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作者 方叶林 朱志刚 陆海云 《地理与地理信息科学》 北大核心 2025年第1期134-141,共8页
基于2009—2020年长三角城市群和珠三角城市群的城市面板数据,综合运用Super-SBM模型、非参数核密度估计、标准差椭圆等方法探讨旅游生态效率时空演化轨迹,并借助面板Tobit模型揭示其影响因素。结果表明:(1)城市群旅游生态效率时序演化... 基于2009—2020年长三角城市群和珠三角城市群的城市面板数据,综合运用Super-SBM模型、非参数核密度估计、标准差椭圆等方法探讨旅游生态效率时空演化轨迹,并借助面板Tobit模型揭示其影响因素。结果表明:(1)城市群旅游生态效率时序演化具有阶段性特征。长三角城市群与珠三角城市群旅游生态效率均具有波动提升态势,前者核密度曲线呈现“单峰”向“双峰”演化以及峰距逐渐变窄的右移趋势,后者核密度曲线具有“多峰”向“双峰”演化以及右尾延展度变小的右移趋势。(2)城市群旅游生态效率具有空间异质性。长三角城市群旅游生态效率呈现东部沿海城市较高、中西部偏低的“高高集聚、低低集聚”空间分布格局,旅游生态效率重心呈东北—西南方向移动;珠三角城市群呈现以东部珠江入海口附近高、西部低的空间分布格局,旅游生态效率重心呈西北—东南方向移动。(3)城市群旅游生态效率影响因素具有综合性与差异性。经济发展、对外开放对长三角城市群旅游生态效率具有正向推动作用,产业结构与政府调控负向抑制作用明显;产业结构、科技创新与对外开放对珠三角城市群旅游生态效率正向推动作用较大,信息化水平呈负向抑制作用。 展开更多
关键词 旅游生态效率 时空演化 TOBIT模型 长三角城市群 珠三角城市群
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离散T-S模糊时滞系统输出反馈容错控制
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作者 游国栋 张海龙 +2 位作者 武劲圆 李兴韫 沈治方 《天津科技大学学报》 2025年第5期73-80,共8页
研究一类带有状态时滞和执行器故障的离散T-S模糊系统的容错控制问题。利用delta算子方法设计全维状态观测器,观测系统不可测量的状态。考虑到执行器会发生故障,对系统建立执行器故障模型,利用并行式补偿原理设计全维状态观测器的输出... 研究一类带有状态时滞和执行器故障的离散T-S模糊系统的容错控制问题。利用delta算子方法设计全维状态观测器,观测系统不可测量的状态。考虑到执行器会发生故障,对系统建立执行器故障模型,利用并行式补偿原理设计全维状态观测器的输出反馈控制器,并通过求解线性矩阵不等式给出了使系统稳定的充分条件。仿真结果进一步验证了本文设计方法的有效性。 展开更多
关键词 离散T-S模糊模型 delta算子 容错控制 状态观测器 输出反馈 时滞系统 线性矩阵不等式
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长三角城市群人口结构变迁对碳排放影响的异质性
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作者 崔连标 宋国锋 朱磊 《中国人口·资源与环境》 北大核心 2025年第7期68-81,共14页
人口老龄化与实现“双碳”目标是中国面临的两大挑战,人口结构在动态重塑社会需求和劳动供给的同时,为“双碳”目标的实现带来潜在的不确定性,协调未来人口发展和碳减排是亟待解决的现实难题。基于此,该研究以长江三角洲城市群为研究对... 人口老龄化与实现“双碳”目标是中国面临的两大挑战,人口结构在动态重塑社会需求和劳动供给的同时,为“双碳”目标的实现带来潜在的不确定性,协调未来人口发展和碳减排是亟待解决的现实难题。基于此,该研究以长江三角洲城市群为研究对象,充分考虑区域异质性,运用有限混合模型,探讨人口老龄化和人力资本对区域碳排放的非线性关联,剖析不同城市的路径转换特征,并通过在模型中添加伴随变量,探究绿色技术创新和产业结构升级对路径转换的潜在作用机理。结果显示:①长江三角洲城市群中老龄化与碳排放间存在显著倒“U”形关系。从整体上看,当老龄化程度超过22.54%时,老龄化的降碳优势才得以发挥,但目前大部分城市仍未超出拐点水平,老龄化仍呈现促碳效应。②人力资本对碳排放的影响存在典型的区域异质性。以杭州、南京、合肥等为代表的城市呈现显著倒“U”形关系,以苏州和无锡等为代表的地区则呈现线性负相关关系。③绿色技术创新和产业结构升级能够促进人口老龄化、人力资本对碳排放倒“U”形关系的形成,加速拐点到达并强化两者的降碳效应。该研究不仅有助于明晰人口老龄化与碳排放间复杂的数量依存关系,还可为不同地区权衡人口发展和碳减排提供一定的决策支持。 展开更多
关键词 人口老龄化 人力资本 “双碳”目标 有限混合模型 长三角城市群
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区域经济韧性分解拓展及其应用研究——以长三角地区为例
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作者 丁建军 周传辉 《当代经济》 2025年第1期81-91,共11页
随着韧性时代的到来,区域经济韧性及其构成备受关注,其测度和分解方法是研究的难点。在Martin将区域经济韧性分解为产业结构韧性分量和竞争力韧性分量的基础上,借鉴偏离-份额分析拓展模型Esteban-Marquillas模型,进一步将区域经济韧性... 随着韧性时代的到来,区域经济韧性及其构成备受关注,其测度和分解方法是研究的难点。在Martin将区域经济韧性分解为产业结构韧性分量和竞争力韧性分量的基础上,借鉴偏离-份额分析拓展模型Esteban-Marquillas模型,进一步将区域经济韧性分解为产业结构韧性分量、净竞争力韧性分量和分配韧性分量,并以我国经济最为活跃的长三角地区为例,对1993—2019年间各地市的经济韧性进行测度和分解,与现有方法相比,该分解拓展为区域经济韧性解构、精细化分析以及精准实施增韧干预提供了新的工具。 展开更多
关键词 区域经济韧性 偏离-份额分析法 Esteban-Marquillas模型 长三角地区
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领军企业对科技创新和产业创新融合发展的促进效应及其机理
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作者 滕堂伟 兰玲 《华东师范大学学报(哲学社会科学版)》 北大核心 2025年第5期187-204,239,共19页
企业是扎实推进科技创新和产业创新融合的关键主体,城市是科技创新和产业创新融合的重要空间载体。通过利用2013—2023年长三角地区41个城市的面板数据进行实证分析后发现,研究期内,长三角城市科技创新和产业创新融合水平增长131.35%,... 企业是扎实推进科技创新和产业创新融合的关键主体,城市是科技创新和产业创新融合的重要空间载体。通过利用2013—2023年长三角地区41个城市的面板数据进行实证分析后发现,研究期内,长三角城市科技创新和产业创新融合水平增长131.35%,城市间差异扩大107.73%。领军企业显著推动了城市科技创新和产业创新融合水平的提升,且在经济核心城市和都市圈内城市更为明显。本地技术溢出、风险资本规模、科技服务生态等具有显著的调节效应,能够强化领军企业对科技创新和产业创新融合的正向作用。空间计量表明,领军企业对邻近地区科技创新和产业创新融合存在正向空间溢出效应。上述结论为培育壮大领军企业以推动科技创新和产业创新深度融合发展,提供了经验证据和政策启示。 展开更多
关键词 领军企业 科技创新 产业创新 空间杜宾模型 长三角
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中国ETF期权Delta对冲收益的日夜特征研究 被引量:2
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作者 刘彦初 汤昊文 钱潮阳 《管理科学学报》 CSSCI CSCD 北大核心 2024年第2期136-158,共23页
期权市场是现代金融市场的重要组成部分,研究期权市场Delta对冲收益的日夜特征,对于理解期权市场运行机制以及降低金融市场风险具有重要意义.本文使用我国2015年—2021年股票ETF期权数据,研究了期权Delta对冲收益的日夜特征.研究结果表... 期权市场是现代金融市场的重要组成部分,研究期权市场Delta对冲收益的日夜特征,对于理解期权市场运行机制以及降低金融市场风险具有重要意义.本文使用我国2015年—2021年股票ETF期权数据,研究了期权Delta对冲收益的日夜特征.研究结果表明,总体上Delta对冲的隔夜收益为负、日内收益不显著;认购期权和认沽期权的Delta对冲收益具有非对称性,即认购期权日内为负、隔夜为正,而认沽期权恰好相反.即使替换为基于波动率和标的资产价格关系的对冲模型,非对称性异象仍然存在.这些发现不同于美国期权市场的Delta对冲收益日内为正、隔夜为负的特征.本文进一步探讨了可能的成因:从风险溢价看,波动率风险溢价可以解释总体上负的隔夜对冲收益,但是不能解释Delta对冲收益的非对称性;从模型误差看,模型误差与标的资产收益共同作用影响了Delta对冲收益;从交易制度看,T+1交易制度约束造成了标的资产日夜收益反转,进而导致了对冲收益的非对称性,并且T+1交易制度约束越强,对冲收益的非对称性越明显.本文将丰富我国期权市场Delta对冲效率、交易制度对金融市场影响的相关研究,有利于提高投资者的风险管理水平、增进监管者对市场行为的理解,从而推动中国多层次资本市场的高质量发展. 展开更多
关键词 ETF期权 delta对冲收益 日内和隔夜 风险溢价 模型误差 T+1交易制度
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基于PSO-SVR模型的长三角城市群碳达峰情景模拟研究
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作者 吴冠岑 章聪颖 +1 位作者 廖金星 牛星 《生态经济》 北大核心 2025年第7期41-48,共8页
论文基于2006—2019年长三角城市群数据,使用PSO-SVR模型并结合情景分析法对基准情景、产业优化情景、土地集约利用情景和碳减排强化情景等8种情景下长三角城市群的碳排放进行预测。结果表明:(1)PSO-SVR模型能够有效提升模型的预测精度... 论文基于2006—2019年长三角城市群数据,使用PSO-SVR模型并结合情景分析法对基准情景、产业优化情景、土地集约利用情景和碳减排强化情景等8种情景下长三角城市群的碳排放进行预测。结果表明:(1)PSO-SVR模型能够有效提升模型的预测精度。(2)长三角城市群在预测期内的碳排放呈现明显的倒“U”型趋势;(3)基准情景下长三角城市群将在2033年达峰,碳减排强化情景将在2031年实现碳达峰,其他情景均在2032年实现碳达峰。研究为长三角城市群在兼顾社会经济稳定发展前提下早日实现“双碳”目标提供了参考。 展开更多
关键词 碳达峰 PSO-SVR模型 情景模拟 长三角城市群
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辽河三角洲粮食主产区耕地生态安全动态评估与监管
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作者 王耕 刘嘉玲 《辽宁师范大学学报(自然科学版)》 2025年第3期289-297,共9页
辽河三角洲是东北地区粮食主产区之一,研究其耕地生态安全状态和发展对于全国粮食质量检测和发展具有重要意义.为系统研究辽河三角洲地区耕地生态系统的质量状况与发展趋势,利用驱动力压力状态影响响应(DPSIR)模型、综合评价法和障碍度... 辽河三角洲是东北地区粮食主产区之一,研究其耕地生态安全状态和发展对于全国粮食质量检测和发展具有重要意义.为系统研究辽河三角洲地区耕地生态系统的质量状况与发展趋势,利用驱动力压力状态影响响应(DPSIR)模型、综合评价法和障碍度模型,综合分析辽河三角洲2000—2020年耕地生态安全状况,并提出合理性建议.研究表明,2000—2020年辽河三角洲地区耕地生态安全持续向好,已经达到较安全水平.在生态安全子系统评价分析中,压力和响应子系统呈现先下降后上升的趋势,状态、驱动力和影响子系统呈现稳步上升的趋势.对辽河三角洲粮食主产区提出合理性、针对性建议并为保护辽三角地区耕地生态安全做规划,实现辽河三角洲粮食主产区耕地生态安全可持续发展. 展开更多
关键词 耕地 生态安全 DPSIR模型 障碍度模型 辽河三角洲
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基于多层感知机模型的长三角水稻种植区净生态系统碳通量模拟 被引量:3
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作者 席闻阳 何建军 +2 位作者 王智麟 郭立峰 李亚荣 《高原气象》 北大核心 2025年第1期191-200,共10页
中国长江三角洲地区(以下简称长三角地区)是典型的水稻种植区,其碳源汇对区域气候和环境具有重要影响。本文系统地分析了长三角地区净生态系统碳交换量(net ecosystem exchange,NEE)与各个气象因子之间的关系,发现NEE与太阳短波辐射的... 中国长江三角洲地区(以下简称长三角地区)是典型的水稻种植区,其碳源汇对区域气候和环境具有重要影响。本文系统地分析了长三角地区净生态系统碳交换量(net ecosystem exchange,NEE)与各个气象因子之间的关系,发现NEE与太阳短波辐射的相关性最强,其次与湿度相关参量(饱和水汽压差、相对湿度)等呈现较强的相关性。同时,NEE与太阳辐射、气温、湿度因子、风速和摩擦速度的相关性呈现明显的昼夜变化。基于上述分析,本文利用NEE和气象观测数据构建了长三角水稻下垫面多层感知机(Multilayer perceptron,MLP)NEE模拟模型,评估了模型的模拟效果及其时空稳定性。构建的MLP模型能较好地拟合NEE,训练集模拟的NEE与观测值的相关系数达到0.88,均方根误差为5.34μmol·m^(-2)·s^(-1);MLP模型在模拟长三角水稻季NEE时表现良好,在东台和寿县站点的模拟NEE结果与观测值的相关系数均高于0.78,模型具有较好的时空稳定性;MLP模型模拟白天平均NEE的效果好于夜间平均NEE的效果。研究结果揭示了影响水稻碳循环的主要气象因子,为认识长三角水稻种植区碳循环时空分布特征提供支撑,对准确评估全球和区域碳通量具有重要意义。 展开更多
关键词 机器学习 MLP模型 NEE 长江三角洲地区 水稻种植区
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