期刊文献+
共找到781,596篇文章
< 1 2 250 >
每页显示 20 50 100
Exploring the effect of a low-carbon city pilot policies on carbon dioxide emission intensity:Based on the PSM-DID method 被引量:2
1
作者 Yan Song Xiulian Chen +2 位作者 Zhenran Li Zhiyuan Zeng Ming Zhang 《Chinese Journal of Population,Resources and Environment》 2022年第3期209-216,共8页
In 2010,the National Development and Reform Commission launched the low-carbon city(LCC)pilot pro‐gram.The scope of the pilot program was then gradually expanded to address the dilemma concerning eco‐nomic developme... In 2010,the National Development and Reform Commission launched the low-carbon city(LCC)pilot pro‐gram.The scope of the pilot program was then gradually expanded to address the dilemma concerning eco‐nomic development and low-carbon transition.Selecting the second batch of LCCs in China,this study uses a combination of propensity score matching and difference-in-differences models to determine the effect of LCC pilot policies on CO_(2) emission intensity.We also used the mediation effect model to further investigate its in‐ternal mechanism.The findings of the study are as follows.First,the LCC pilot policy plays an important role in reducing carbon emissions.Second,LCC pilots policies reduce CO_(2) emissions through intermediary paths of output adjustment and technological innovation.Third,our heterogeneity analysis reveals that cities with higher levels of economic growth and better levels of human capital have superior carbon emission reduction effects;lastly,non-resource-based cities have better carbon emission reduction effects. 展开更多
关键词 Low-carbon city(LCC) Carbon emissions psm-did Output adjustment Technology innovation
在线阅读 下载PDF
A New Inversion-free Iterative Method for Solving the Nonlinear Matrix Equation and Its Application in Optimal Control
2
作者 GAO Xiangyu XIE Weiwei ZHANG Lina 《应用数学》 北大核心 2026年第1期143-150,共8页
In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to ... In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method. 展开更多
关键词 Nonlinear matrix equation Maximal positive definite solution Inversion-free iterative method Optimal control
在线阅读 下载PDF
Centralized Circumcentered-Reection Method for Solving the Convex Feasibility Problem in Sparse Signal Recovery
3
作者 Chunmei LI Bangjun CHEN Xuefeng DUAN 《Journal of Mathematical Research with Applications》 2026年第1期119-133,共15页
Convex feasibility problems are widely used in image reconstruction,sparse signal recovery,and other areas.This paper is devoted to considering a class of convex feasibility problem arising from sparse signal recovery... Convex feasibility problems are widely used in image reconstruction,sparse signal recovery,and other areas.This paper is devoted to considering a class of convex feasibility problem arising from sparse signal recovery.We rst derive the projection formulas for a vector onto the feasible sets.The centralized circumcentered-reection method is designed to solve the convex feasibility problem.Some numerical experiments demonstrate the feasibility and e ectiveness of the proposed algorithm,showing superior performance compared to conventional alternating projection methods. 展开更多
关键词 convex feasibility problem centralized circumcentered-re ection method sparse signal recovery compressed sensing
原文传递
Numerical Simulation of the Welding Deformation of Marine Thin Plates Based on a Temperature Gradient-thermal Strain Method
4
作者 Lin Wang Yugang Miao +3 位作者 Zhenjian Zhuo Chunxiang Lin Benshun Zhang Duanfeng Han 《哈尔滨工程大学学报(英文版)》 2026年第1期122-135,共14页
Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The t... Marine thin plates are susceptible to welding deformation owing to their low structural stiffness.Therefore,the efficient and accurate prediction of welding deformation is essential for improving welding quality.The traditional thermal elastic-plastic finite element method(TEP-FEM)can accurately predict welding deformation.However,its efficiency is low because of the complex nonlinear transient computation,making it difficult to meet the needs of rapid engineering evaluation.To address this challenge,this study proposes an efficient prediction method for welding deformation in marine thin plate butt welds.This method is based on the coupled temperature gradient-thermal strain method(TG-TSM)that integrates inherent strain theory with a shell element finite element model.The proposed method first extracts the distribution pattern and characteristic value of welding-induced inherent strain through TEP-FEM analysis.This strain is then converted into the equivalent thermal load applied to the shell element model for rapid computation.The proposed method-particularly,the gradual temperature gradient-thermal strain method(GTG-TSM)-achieved improved computational efficiency and consistent precision.Furthermore,the proposed method required much less computation time than the traditional TEP-FEM.Thus,this study lays the foundation for future prediction of welding deformation in more complex marine thin plates. 展开更多
关键词 Marine thin plate Welding deformation Numerical simulation Temperature gradient-thermal strain method Shell element
在线阅读 下载PDF
人工智能技术对制造业就业的影响——基于PSM-DID模型 被引量:1
5
作者 龙莹 赵浩然 《华南理工大学学报(社会科学版)》 2025年第3期61-73,共13页
基于2015—2023年的沪深A股上市制造业企业数据,依据是否融入人工智能产业链,将制造业企业划分为AI企业和非AI企业,通过多时点PSM-DID模型探究人工智能技术对我国制造业就业规模与就业结构的影响。研究发现,人工智能技术显著扩大了制造... 基于2015—2023年的沪深A股上市制造业企业数据,依据是否融入人工智能产业链,将制造业企业划分为AI企业和非AI企业,通过多时点PSM-DID模型探究人工智能技术对我国制造业就业规模与就业结构的影响。研究发现,人工智能技术显著扩大了制造业企业的整体就业规模,通过中介效应检验发现,人工智能技术主要通过提高企业研发投入强度来扩大企业的整体就业规模。进一步分析,人工智能技术的应用对研究生学历和高中及以下学历的员工有显著的正向效应,相比之下,大专学历的员工被人工智能技术的替代效应所挤出,出现“极化”现象。而且,人工智能技术对制造业就业规模的影响在不同部门、不同细分行业和不同地区中表现各异。在此基础上,提出政府和企业可通过政策引导、技术创新和教育培训,共同推动制造业可持续高质量发展,确保产业转型过程中就业市场的平稳过渡与繁荣。 展开更多
关键词 人工智能技术 制造业企业 就业规模 就业结构 psm-did模型
在线阅读 下载PDF
区域大气污染协同治理能促进空气质量改善吗?--基于中国279个城市的PSM-DID实证研究 被引量:3
6
作者 陆安颉 周建国 《长江流域资源与环境》 北大核心 2025年第3期652-667,共16页
当前我国复合型、跨域性空气污染问题日益突出,传统的属地治理模式再难应对,急需打破行政区划限制,推进区域大气污染协同治理。首先对大气污染协同治理政策的作用机理展开分析并提出研究假设;进一步基于2013~2020年我国279个地级及以上... 当前我国复合型、跨域性空气污染问题日益突出,传统的属地治理模式再难应对,急需打破行政区划限制,推进区域大气污染协同治理。首先对大气污染协同治理政策的作用机理展开分析并提出研究假设;进一步基于2013~2020年我国279个地级及以上城市的面板数据,运用双重差分倾向得分匹配法(PSM-DID),实证探究区域大气污染协同治理的政策效果和作用机制。研究发现:(1)基准回归分析结果表明,协同治理政策的实施显著降低了城市AQI指数和PM10、SO_(2)、NO_(2)、PM_(2.5)污染物的浓度,整体上促进了区域空气质量改善,一系列稳健性检验均表明结论的可靠性。(2)区域异质性分析结果表明,京津冀地区协同治理效果在促进空气质量改善和污染减排方面均显著优于长三角地区。(3)作用机制分析结果表明,区域大气污染协同治理主要通过促进产业结构升级、提升技术创新水平和加大污染源治理投资力度来改善区域空气质量,有效治理区域性、复合型大气污染问题。研究进一步提出政策建议。 展开更多
关键词 大气污染 区域协同治理 空气质量 psm-did
原文传递
高铁开通对中国航空网络结构特征的影响——基于PSM-DID模型的实证分析
7
作者 景崇毅 郭韩一萌 高玉香 《交通运输研究》 2025年第2期54-64,共11页
为探究高铁网络扩张对中国航空网络结构的影响及其空间异质性特征,并为优化空铁竞合关系提供决策参考,采用PSM-DID模型,利用2000—2018年的高铁开通数据和航空网络数据,从航空网络的连通性、紧密性、易达性和中介性4个维度对高铁开通给... 为探究高铁网络扩张对中国航空网络结构的影响及其空间异质性特征,并为优化空铁竞合关系提供决策参考,采用PSM-DID模型,利用2000—2018年的高铁开通数据和航空网络数据,从航空网络的连通性、紧密性、易达性和中介性4个维度对高铁开通给航空网络结构特征带来的影响进行分析,并根据地区及机场规模差异等进行讨论。结果表明:①高铁开通对航空网络结构产生了显著的负面冲击;②地理位置、经济、环境等因素的差异导致冲击强度表现出“中部地区>东部地区>西部地区”的特征;③大型机场通过替代效应与互补效应的协同作用,能缓解高铁运营带来的客源分流压力,展现出较中小型机场更为突出的抗风险能力;④高铁开通拓展了机场群的市场辐射范围。基于此,提出如下政策建议:西部地区应优化短途航线布局;中小机场需发展低成本航空提升运营效率,大型机场应推进空铁联运整合;优先培育枢纽机场群,通过国际长航线开拓,提升网络韧性。 展开更多
关键词 交通运输 高速铁路 航空网络 网络结构 psm-did模型
在线阅读 下载PDF
设立重点生态功能区对生态经济协调发展的影响研究--基于PSM-DID模型的实证分析
8
作者 黄海燕 唐洁 《绿色科技》 2025年第1期223-228,共6页
重点生态功能区承担着重要的生态保障与生态产品供给功能,在接受中央财政转移支付的同时也实行严格的产业准入制度,因此对于设立重点生态功能区能否有效促进生态经济协调发展是值得关注的问题。本文将重点生态功能区的设立作为一项“准... 重点生态功能区承担着重要的生态保障与生态产品供给功能,在接受中央财政转移支付的同时也实行严格的产业准入制度,因此对于设立重点生态功能区能否有效促进生态经济协调发展是值得关注的问题。本文将重点生态功能区的设立作为一项“准自然实验”,基于2006-2022年贵州省72个县的面板数据,采用双重差分法(PSM-DID模型)评估重点生态功能区设立对贵州省72个县生态经济协调发展的影响。研究发现:重点生态功能区的设立能显著促进生态经济协调发展,机制分析结果表明重点生态功能区能通过产业结构升级效应、劳动力要素及资金要素的集聚效应促进生态经济协调发展。针对上述结论提出以下建议:①加快探索重点生态功能区生态产品价值实现路径,促进生态经济融合发展;②拓展重点生态功能区转移支付补偿方式并促进资金分配合理化。 展开更多
关键词 重点生态功能区 psm-did模型 生态经济协调发展 生态系统服务价值
在线阅读 下载PDF
Structural Modal Parameter Recognition and Related Damage Identification Methods under Environmental Excitations:A Review 被引量:5
9
作者 Chao Zhang Shang-Xi Lai Hua-Ping Wang 《Structural Durability & Health Monitoring》 EI 2025年第1期25-54,共30页
Modal parameters can accurately characterize the structural dynamic properties and assess the physical state of the structure.Therefore,it is particularly significant to identify the structural modal parameters accordi... Modal parameters can accurately characterize the structural dynamic properties and assess the physical state of the structure.Therefore,it is particularly significant to identify the structural modal parameters according to the monitoring data information in the structural health monitoring(SHM)system,so as to provide a scientific basis for structural damage identification and dynamic model modification.In view of this,this paper reviews methods for identifying structural modal parameters under environmental excitation and briefly describes how to identify structural damages based on the derived modal parameters.The paper primarily introduces data-driven modal parameter recognition methods(e.g.,time-domain,frequency-domain,and time-frequency-domain methods,etc.),briefly describes damage identification methods based on the variations of modal parameters(e.g.,natural frequency,modal shapes,and curvature modal shapes,etc.)and modal validation methods(e.g.,Stability Diagram and Modal Assurance Criterion,etc.).The current status of the application of artificial intelligence(AI)methods in the direction of modal parameter recognition and damage identification is further discussed.Based on the pre-vious analysis,the main development trends of structural modal parameter recognition and damage identification methods are given to provide scientific references for the optimized design and functional upgrading of SHM systems. 展开更多
关键词 Structural health monitoring data information modal parameters damage identification AI method
在线阅读 下载PDF
Study of the Transport Behavior of Multispherical Proppant in Intersecting Fracture Based on Discrete Element Method 被引量:1
10
作者 Chengyong Peng JianshuWu +2 位作者 Mao Jiang Biao Yin Yishan Lou 《Energy Engineering》 EI 2025年第1期185-201,共17页
To analyze the differences in the transport and distribution of different types of proppants and to address issues such as the short effective support of proppant and poor placement in hydraulically intersecting fract... To analyze the differences in the transport and distribution of different types of proppants and to address issues such as the short effective support of proppant and poor placement in hydraulically intersecting fractures,this study considered the combined impact of geological-engineering factors on conductivity.Using reservoir production parameters and the discrete elementmethod,multispherical proppants were constructed.Additionally,a 3D fracture model,based on the specified conditions of the L block,employed coupled(Computational Fluid Dynamics)CFD-DEM(Discrete ElementMethod)for joint simulations to quantitatively analyze the transport and placement patterns of multispherical proppants in intersecting fractures.Results indicate that turbulent kinetic energy is an intrinsic factor affecting proppant transport.Moreover,the efficiency of placement and migration distance of low-sphericity quartz sand constructed by the DEM in the main fracture are significantly reduced compared to spherical ceramic proppants,with a 27.7%decrease in the volume fraction of the fracture surface,subsequently affecting the placement concentration and damaging fracture conductivity.Compared to small-angle fractures,controlling artificial and natural fractures to expand at angles of 45°to 60°increases the effective support length by approximately 20.6%.During hydraulic fracturing of gas wells,ensuring the fracture support area and post-closure conductivity can be achieved by controlling the sphericity of proppants and adjusting the perforation direction to control the direction of artificial fractures. 展开更多
关键词 Hydraulic fracturing discrete element method PROPPANT SPHERICITY CFD-DEM
在线阅读 下载PDF
政府引导基金对企业成长性的影响——基于PSM-DID的实证分析
11
作者 杜佳凝 周霞 《商业会计》 2025年第4期111-114,共4页
政府引导基金是创投出资的主要力量,具有缓解市场失灵、推动科技创新繁荣的重要作用。文章选取创业板上市公司2017-2022年间的数据作为研究样本,在分析政府引导基金对企业成长性的影响时,采用了倾向得分匹配双重差分法(PSM-DID),研究发... 政府引导基金是创投出资的主要力量,具有缓解市场失灵、推动科技创新繁荣的重要作用。文章选取创业板上市公司2017-2022年间的数据作为研究样本,在分析政府引导基金对企业成长性的影响时,采用了倾向得分匹配双重差分法(PSM-DID),研究发现,政府引导基金对提升企业的成长性具有显著的正向影响;异质性分析发现,相对于非高新技术企业,政府引导基金的投入更有益于提高高新技术企业成长性。这一研究结论进一步丰富了企业成长性的影响因素,为上市公司发展转型、提升企业成长能力提供了一定参考和借鉴。国家应该积极设立政府引导基金,发挥政府引导基金的引导作用,吸引社会资本参与投资,优化政府引导基金的运作效率以及投资结构配置。 展开更多
关键词 政府引导基金 企业成长性 psm-did
在线阅读 下载PDF
绿色信贷对商业银行风险承担能力的影响研究——基于PSM-DID模型实证分析
12
作者 陶圆 李辉 丁勇 《华北金融》 2025年第1期1-14,共14页
加快实现绿色金融发展是贯彻落实新发展理念的战略要求。本文以2007—2022年81家商业银行微观数据为样本,采用PSM-DID模型和非线性回归模型分析银行绿色信贷与风险承担能力之间的关系,并进一步分析绿色信贷占比对银行风险承担能力的作... 加快实现绿色金融发展是贯彻落实新发展理念的战略要求。本文以2007—2022年81家商业银行微观数据为样本,采用PSM-DID模型和非线性回归模型分析银行绿色信贷与风险承担能力之间的关系,并进一步分析绿色信贷占比对银行风险承担能力的作用机制。研究表明:(1)实施绿色信贷政策和增加绿色信贷占比均能显著提升银行的风险承担能力。(2)银行绿色信贷占比与其风险承担能力呈“倒U”形关系。(3)从传导机制来看,绿色信贷提升银行风险承担水平的途径主要是风险转移效应和声誉效应,并且声誉效应对绿色信贷提高银行风险承担能力起正向的调节作用。 展开更多
关键词 绿色信贷 银行风险承担 psm-did 风险转移效应 声誉效应
在线阅读 下载PDF
Combing the Entropy Weight Method with Fuzzy Mathematics for Assessing the Quality and Post-Ripening Mechanism of High-Temperature Daqu during Storage 被引量:1
13
作者 YANG Junlin YANG Shaojuan +8 位作者 WU Cheng YIN Yanshun YOU Xiaolong ZHAO Wenyu ZHU Anran WANG Jia HU Feng HU Jianfeng WANG Diqiang 《食品科学》 北大核心 2025年第9期48-62,共15页
This study investigated the physicochemical properties,enzyme activities,volatile flavor components,microbial communities,and sensory evaluation of high-temperature Daqu(HTD)during the maturation process,and a standar... This study investigated the physicochemical properties,enzyme activities,volatile flavor components,microbial communities,and sensory evaluation of high-temperature Daqu(HTD)during the maturation process,and a standard system was established for comprehensive quality evaluation of HTD.There were obvious changes in the physicochemical properties,enzyme activities,and volatile flavor components at different storage periods,which affected the sensory evaluation of HTD to a certain extent.The results of high-throughput sequencing revealed significant microbial diversity,and showed that the bacterial community changed significantly more than did the fungal community.During the storage process,the dominant bacterial genera were Kroppenstedtia and Thermoascus.The correlation between dominant microorganisms and quality indicators highlighted their role in HTD quality.Lactococcus,Candida,Pichia,Paecilomyces,and protease activity played a crucial role in the formation of isovaleraldehyde.Acidic protease activity had the greatest impact on the microbial community.Moisture promoted isobutyric acid generation.Furthermore,the comprehensive quality evaluation standard system was established by the entropy weight method combined with multi-factor fuzzy mathematics.Consequently,this study provides innovative insights for comprehensive quality evaluation of HTD during storage and establishes a groundwork for scientific and rational storage of HTD and quality control of sauce-flavor Baijiu. 展开更多
关键词 microbial community high-temperature Daqu comprehensive quality evaluation entropy weight method maturation process
在线阅读 下载PDF
In situ stress inversion using nonlinear stress boundaries achieved by the bubbling method 被引量:1
14
作者 Xige Liu Chenchun Huang +3 位作者 Wancheng Zhu Joung Oh Chengguo Zhang Guangyao Si 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第3期1510-1527,共18页
Due to the heterogeneity of rock masses and the variability of in situ stress,the traditional linear inversion method is insufficiently accurate to achieve high accuracy of the in situ stress field.To address this cha... Due to the heterogeneity of rock masses and the variability of in situ stress,the traditional linear inversion method is insufficiently accurate to achieve high accuracy of the in situ stress field.To address this challenge,nonlinear stress boundaries for a numerical model are determined through regression analysis of a series of nonlinear coefficient matrices,which are derived from the bubbling method.Considering the randomness and flexibility of the bubbling method,a parametric study is conducted to determine recommended ranges for these parameters,including the standard deviation(σb)of bubble radii,the non-uniform coefficient matrix number(λ)for nonlinear stress boundaries,and the number(m)and positions of in situ stress measurement points.A model case study provides a reference for the selection of these parameters.Additionally,when the nonlinear in situ stress inversion method is employed,stress distortion inevitably occurs near model boundaries,aligning with the Saint Venant's principle.Two strategies are proposed accordingly:employing a systematic reduction of nonlinear coefficients to achieve high inversion accuracy while minimizing significant stress distortion,and excluding regions with severe stress distortion near the model edges while utilizing the central part of the model for subsequent simulations.These two strategies have been successfully implemented in the nonlinear in situ stress inversion of the Xincheng Gold Mine and have achieved higher inversion accuracy than the linear method.Specifically,the linear and nonlinear inversion methods yield root mean square errors(RMSE)of 4.15 and 3.2,and inversion relative errors(δAve)of 22.08%and 17.55%,respectively.Therefore,the nonlinear inversion method outperforms the traditional multiple linear regression method,even in the presence of a systematic reduction in the nonlinear stress boundaries. 展开更多
关键词 In situ stress field Inversion method The bubbling method Nonlinear stress boundary Multiple linear regression method
在线阅读 下载PDF
Insight Into the Separation-of-Variable Methods for the Closed-Form Solutions of Free Vibration of Rectangular Thin Plates
15
作者 Yufeng Xing Ye Yuan Gen Li 《Computer Modeling in Engineering & Sciences》 SCIE EI 2025年第1期329-355,共27页
The separation-of-variable(SOV)methods,such as the improved SOV method,the variational SOV method,and the extended SOV method,have been proposed by the present authors and coworkers to obtain the closed-form analytica... The separation-of-variable(SOV)methods,such as the improved SOV method,the variational SOV method,and the extended SOV method,have been proposed by the present authors and coworkers to obtain the closed-form analytical solutions for free vibration and eigenbuckling of rectangular plates and circular cylindrical shells.By taking the free vibration of rectangular thin plates as an example,this work presents the theoretical framework of the SOV methods in an instructive way,and the bisection–based solution procedures for a group of nonlinear eigenvalue equations.Besides,the explicit equations of nodal lines of the SOV methods are presented,and the relations of nodal line patterns and frequency orders are investigated.It is concluded that the highly accurate SOV methods have the same accuracy for all frequencies,the mode shapes about repeated frequencies can also be precisely captured,and the SOV methods do not have the problem of missing roots as well. 展开更多
关键词 Separation-of-variable method Rayleigh quotient nodal line eigenvalue equation bisection method
在线阅读 下载PDF
Improved methods,properties,applications and prospects of microbial induced carbonate precipitation(MICP)treated soil:A review 被引量:2
16
作者 Xuanshuo Zhang Hongyu Wang +3 位作者 Ya Wang Jinghui Wang Jing Cao Gang Zhang 《Biogeotechnics》 2025年第1期34-54,共21页
Soil improvement is one of the most important issues in geotechnical engineering practice.The wide application of traditional improvement techniques(cement/chemical materials)are limited due to damage ecological en-vi... Soil improvement is one of the most important issues in geotechnical engineering practice.The wide application of traditional improvement techniques(cement/chemical materials)are limited due to damage ecological en-vironment and intensify carbon emissions.However,the use of microbially induced calcium carbonate pre-cipitation(MICP)to obtain bio-cement is a novel technique with the potential to induce soil stability,providing a low-carbon,environment-friendly,and sustainable integrated solution for some geotechnical engineering pro-blems in the environment.This paper presents a comprehensive review of the latest progress in soil improvement based on the MICP strategy.It systematically summarizes and overviews the mineralization mechanism,influ-encing factors,improved methods,engineering characteristics,and current field application status of the MICP.Additionally,it also explores the limitations and correspondingly proposes prospective applications via the MICP approach for soil improvement.This review indicates that the utilization of different environmental calcium-based wastes in MICP and combination of materials and MICP are conducive to meeting engineering and market demand.Furthermore,we recommend and encourage global collaborative study and practice with a view to commercializing MICP technique in the future.The current review purports to provide insights for engineers and interdisciplinary researchers,and guidance for future engineering applications. 展开更多
关键词 Soil improvement Bio-cement MICP Improved methods Field application cases
在线阅读 下载PDF
国土空间生态保护修复对中国脱贫地区经济发展的影响——基于PSM-DID方法的实证分析
17
作者 张帅航 原野 +4 位作者 苗颖凤 曹辰瑜 赵嘉瑜 王霜 李倩 《干旱区地理》 北大核心 2025年第5期930-940,共11页
探究国土空间生态保护修复对中国脱贫地区经济发展的影响,可为脱贫地区经济可持续发展及后脱贫时代相对贫困地区乡村振兴工作提供科学依据。运用倾向得分匹配-双重差分(PSM-DID)模型,对我国“十三五”期间及“十四五”期间第一批、第二... 探究国土空间生态保护修复对中国脱贫地区经济发展的影响,可为脱贫地区经济可持续发展及后脱贫时代相对贫困地区乡村振兴工作提供科学依据。运用倾向得分匹配-双重差分(PSM-DID)模型,对我国“十三五”期间及“十四五”期间第一批、第二批国家级山水林田湖草沙一体化保护和修复工程项目(“山水工程”)共涉及的58个国家级脱贫县和与其自然社会经济本底条件类似的182个未列入国家“山水工程”的脱贫县的2010—2020年的经济面板数据进行对比,测度国土空间生态保护修复对中国脱贫地区经济发展的影响。结果表明:(1)在其他条件不变的情况下,相对于未实施国土空间生态保护修复的脱贫地区,实施国土空间生态保护修复的脱贫县经济发展速率显著提高了0.0329,这一结论在进行了平衡性检验、平行趋势检验及安慰剂检验等稳健性检验后仍成立。(2)国土空间生态保护修复实施中,宜考量工程实施带动经济发展的近远期效应。生态产品价值实现作为可持续推动脱贫地区经济发展重要手段,宜在完善相关生态产品价值实现制度的基础上,给脱贫地区更多政策支持,助力其实现“绿水青山”向“金山银山”转化。 展开更多
关键词 国土空间生态保护修复 脱贫地区 经济发展 psm-did
在线阅读 下载PDF
一种基于Least Square Method算法的城轨车辆车门动作时间精准判断的研究
18
作者 李宏菱 宋华杰 +3 位作者 马仲智 周辉 李晴 陈龙 《时代汽车》 2025年第3期190-192,共3页
为研究城市轨道交通车辆客室车门动作时间精准性,门的动作主要依靠直流无刷电机的驱动,所以门动作判断的根本,是对电机运动状态的判读,门运动过程中由于电机码盘线受杂波干扰,系统无法准确寻找计时点从而影响系统判断门运动时间;建立波... 为研究城市轨道交通车辆客室车门动作时间精准性,门的动作主要依靠直流无刷电机的驱动,所以门动作判断的根本,是对电机运动状态的判读,门运动过程中由于电机码盘线受杂波干扰,系统无法准确寻找计时点从而影响系统判断门运动时间;建立波形矫正模型,利用数学方法校准波形,让MCU找出最佳计时点并处理(误差不超过10ms),采用最小二乘法模型,通过最小化误差的平方和找到一组数据的最佳函数匹配,求得未知的数据,并使得这些求得的数据与实际数据之间误差的平方和为最小,可精准地得到门动作时间。模拟测试结果表明,门动作时间测算误差所示其误差为7.42ms,小于10ms。 展开更多
关键词 城轨车辆 客室车门 电机码盘 Least Square method算法 门动作时间精准
在线阅读 下载PDF
Research on Bearing Fault Diagnosis Method Based on Deep Learning 被引量:1
19
作者 Ting Zheng 《Journal of Electronic Research and Application》 2025年第1期1-6,共6页
Bearing is an indispensable key component in mechanical equipment,and its working state is directly related to the stability and safety of the whole equipment.In recent years,with the rapid development of artificial i... Bearing is an indispensable key component in mechanical equipment,and its working state is directly related to the stability and safety of the whole equipment.In recent years,with the rapid development of artificial intelligence technology,especially the breakthrough of deep learning technology,it provides a new idea for bearing fault diagnosis.Deep learning can automatically learn features from a large amount of data,has a strong nonlinear modeling ability,and can effectively solve the problems existing in traditional methods.Aiming at the key problems in bearing fault diagnosis,this paper studies the fault diagnosis method based on deep learning,which not only provides a new solution for bearing fault diagnosis but also provides a reference for the application of deep learning in other mechanical fault diagnosis fields. 展开更多
关键词 Deep learning Bearing failure Diagnostic methods
在线阅读 下载PDF
Rendered image denoising method with filtering guided by lighting information 被引量:1
20
作者 MA Minghui HU Xiaojuan +2 位作者 ZHANG Ripei CHEN Chunyi YU Haiyang 《Optoelectronics Letters》 2025年第4期242-248,共7页
The visual noise of each light intensity area is different when the image is drawn by Monte Carlo method.However,the existing denoising algorithms have limited denoising performance under complex lighting conditions a... The visual noise of each light intensity area is different when the image is drawn by Monte Carlo method.However,the existing denoising algorithms have limited denoising performance under complex lighting conditions and are easy to lose detailed information.So we propose a rendered image denoising method with filtering guided by lighting information.First,we design an image segmentation algorithm based on lighting information to segment the image into different illumination areas.Then,we establish the parameter prediction model guided by lighting information for filtering(PGLF)to predict the filtering parameters of different illumination areas.For different illumination areas,we use these filtering parameters to construct area filters,and the filters are guided by the lighting information to perform sub-area filtering.Finally,the filtering results are fused with auxiliary features to output denoised images for improving the overall denoising effect of the image.Under the physically based rendering tool(PBRT)scene and Tungsten dataset,the experimental results show that compared with other guided filtering denoising methods,our method improves the peak signal-to-noise ratio(PSNR)metrics by 4.2164 dB on average and the structural similarity index(SSIM)metrics by 7.8%on average.This shows that our method can better reduce the noise in complex lighting scenesand improvethe imagequality. 展开更多
关键词 establish paramet rendered image denoising Monte Carlo method filtering guided lighting information denoising algorithms image segmentation algorithm rendered image denoising method monte carlo methodhoweverthe
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部