期刊文献+
共找到80,933篇文章
< 1 2 250 >
每页显示 20 50 100
我国公众互联网使用对县级政府公信力的影响——基于CSS 2021数据的分析 被引量:2
1
作者 李斌 孙雪 方錄 《重庆理工大学学报(社会科学)》 2025年第2期158-177,共20页
政府公信力是公众基于政府履职行为而产生的信任评价,是政府永恒追求的主题。为深入研究数字时代公众的互联网使用对县级政府公信力的影响,在“把关人”理论和媒体抑郁症理论基础上,以中国社会状况综合调查(CSS)为数据来源,综合运用多... 政府公信力是公众基于政府履职行为而产生的信任评价,是政府永恒追求的主题。为深入研究数字时代公众的互联网使用对县级政府公信力的影响,在“把关人”理论和媒体抑郁症理论基础上,以中国社会状况综合调查(CSS)为数据来源,综合运用多元回归和因子分析等方法进行研究。研究发现:新时代以来,我国县级政府公信力水平从2013年的2.59增加到2021年的3.06;网民和非网民的政府信任水平同样呈现逐步递增的态势。是否使用互联网显著影响了公众的政府信任水平,网民的政府信任水平低于非网民的政府信任水平;公众使用互联网且有一定使用频率时,互联网使用频率对县级政府公信力无显著影响,而互联网使用频率对县级政府公信力存在的负向显著影响是由公众从“从不使用互联网到使用互联网”这一转变的负向效应所带来的;公众不同的互联网使用方式对县级政府公信力影响不存在显著差异,发展型使用和娱乐型使用均不显著影响县级政府公信力。同时,个体的受教育水平在是否使用互联网对县级政府公信力的负向影响中发挥抑制作用。 展开更多
关键词 数字时代 互联网使用 政府公信力 css数据 政府信任
在线阅读 下载PDF
浅析HTML5+CSS3在网页设计中的特性及优势 被引量:1
2
作者 廖黄鹏 《信息与电脑》 2025年第1期135-137,共3页
为探讨HTML5+CSS3在现代网页设计中的结合效果,文章研究了HTML5与CSS3的特点与优势,分析了HTML5+CSS的结合效果。分析认为,HTML5的语义化标签与多媒体交互功能提升了网页交互性,CSS3的渐变、阴影与动画增强了视觉表现力,二者结合显著优... 为探讨HTML5+CSS3在现代网页设计中的结合效果,文章研究了HTML5与CSS3的特点与优势,分析了HTML5+CSS的结合效果。分析认为,HTML5的语义化标签与多媒体交互功能提升了网页交互性,CSS3的渐变、阴影与动画增强了视觉表现力,二者结合显著优化了用户体验与开发效率,为现代网页设计提供了重要支持。 展开更多
关键词 HTML5 css3 网页设计 多媒体交互
在线阅读 下载PDF
Geometric parameter identification of bridge precast box girder sections based on deep learning and computer vision 被引量:1
3
作者 JIA Jingwei NI Youhao +2 位作者 MAO Jianxiao XU Yinfei WANG Hao 《Journal of Southeast University(English Edition)》 2025年第3期278-285,共8页
To overcome the limitations of low efficiency and reliance on manual processes in the measurement of geometric parameters for bridge prefabricated components,a method based on deep learning and computer vision is deve... To overcome the limitations of low efficiency and reliance on manual processes in the measurement of geometric parameters for bridge prefabricated components,a method based on deep learning and computer vision is developed to identify the geometric parameters.The study utilizes a common precast element for highway bridges as the research subject.First,edge feature points of the bridge component section are extracted from images of the precast component cross-sections by combining the Canny operator with mathematical morphology.Subsequently,a deep learning model is developed to identify the geometric parameters of the precast components using the extracted edge coordinates from the images as input and the predefined control parameters of the bridge section as output.A dataset is generated by varying the control parameters and noise levels for model training.Finally,field measurements are conducted to validate the accuracy of the developed method.The results indicate that the developed method effectively identifies the geometric parameters of bridge precast components,with an error rate maintained within 5%. 展开更多
关键词 bridge precast components section geometry parameters size identification computer vision deep learning
在线阅读 下载PDF
失业保险参保何以影响公众预期经济地位?——基于CSS四期混合截面数据的实证研究
4
作者 李鹏 刁雅琴 帅文颖 《中共福建省委党校(福建行政学院)学报》 北大核心 2025年第5期79-93,共15页
失业保险作为社会保障体系的重要组成部分,对促进经济社会和劳动力市场健康发展、健全社会保障制度体系和保障改善民生具有重要作用。利用中国社会状况综合调查(CSS)四期混合截面数据,在多重共线性检验前提下构建模型,分析失业保险参保... 失业保险作为社会保障体系的重要组成部分,对促进经济社会和劳动力市场健康发展、健全社会保障制度体系和保障改善民生具有重要作用。利用中国社会状况综合调查(CSS)四期混合截面数据,在多重共线性检验前提下构建模型,分析失业保险参保对公众预期经济地位的影响。结果显示,失业保险参保对预期经济地位存在显著影响,同时根据工作满意度对失业保险参保影响预期经济地位的异质性进行分析,并采用模型替换以及倾向得分匹配(PSM)等方法对模型进行稳健性检验和内生性处理。机制分析结果表明,收支状况在失业保险参保对预期经济地位的影响中发挥了中介作用,而当前经济地位则对二者之间的关系起到了调节作用。根据实证结果,提出应加大失业保险政策宣传力度,引导公众树立理性包容的就业观念与失业认知,同时提升失业保险政策综合导向,完善政策工具体系,以适应经济产业结构和劳动力市场变化,推进失业保险制度扩面提质。 展开更多
关键词 失业保险 预期经济地位 css 机制分析
在线阅读 下载PDF
基于DIV+CSS的响应式布局的设计与研究
5
作者 杨学博 孔文淑 陈红娟 《现代信息科技》 2025年第17期88-94,共7页
随着互联网技术的快速发展,Web前端设计在不同设备上的适配性成为提升用户体验的关键。文章以基于DIV+CSS的响应式布局为核心,探讨了其在现代前端设计中的应用与实现。首先分析了响应式布局的基本原理及其与固定布局的对比;接着结合现... 随着互联网技术的快速发展,Web前端设计在不同设备上的适配性成为提升用户体验的关键。文章以基于DIV+CSS的响应式布局为核心,探讨了其在现代前端设计中的应用与实现。首先分析了响应式布局的基本原理及其与固定布局的对比;接着结合现有研究成果,详细介绍了HTML5、CSS3(包括Flexbox和Grid布局)以及JavaScript在响应式布局中的应用。研究表明,基于DIV+CSS的响应式布局设计能够有效提升页面的适配性和用户体验,简化开发流程,提高开发效率。未来,随着前端技术的不断发展,响应式布局将在更多场景中得到广泛应用。 展开更多
关键词 HTML5 DIV+css 响应式布局
在线阅读 下载PDF
Deep imaging of LepR^(+)stromal cells in optically cleared murine bone hemisections
6
作者 Yuehan Ni Jiamiao Wu +23 位作者 Fengqi Liu Yating Yi Xiangjiao Meng Xiang Gao Luyi Xiao Weiwei Zhou Zexi Chen Peng Chu Dan Xing Ye Yuan Donghui Ding Ge Shen Min Yang Ronjie Wu Ling Wang Luiza Martins Nascentes Melo Sien Lin Xiaoguang Cheng Gang Li Alpaslan Tasdogan Jessalyn M.Ubellacker Hu Zhao Shentong Fang Bo Shen 《Bone Research》 2025年第1期104-120,共17页
Tissue clearing combined with high-resolution confocal imaging is a cutting-edge approach for dissecting the three-dimensional(3D)architecture of tissues and deciphering cellular spatial interactions under physiologic... Tissue clearing combined with high-resolution confocal imaging is a cutting-edge approach for dissecting the three-dimensional(3D)architecture of tissues and deciphering cellular spatial interactions under physiological and pathological conditions.Deciphering the spatial interaction of leptin receptor-expressing(LepR^(+))stromal cells with other compartments in the bone marrow is crucial for a deeper understanding of the stem cell niche and the skeletal tissue.In this study,we introduce an optimized protocol for the 3D analysis of skeletal tissues,enabling the visualization of hematopoietic and stromal cells,especially LepR+stromal cells,within optically cleared bone hemisections.Our method preserves the 3D tissue architecture and is extendable to other hematopoietic sites such as calvaria and vertebrae.The protocol entails tissue fixation,decalcification,and cryosectioning to reveal the marrow cavity.Completed within approximately 12 days,this process yields highly transparent tissues that maintain genetically encoded or antibody-stained fluorescent signals.The bone hemisections are compatible with diverse antibody labeling strategies.Confocal microscopy of these transparent samples allows for qualitative and quantitative image analysis using Aivia or Bitplane Imaris software,assessing a spectrum of parameters.With proper storage,the fluorescent signal in the stained and cleared bone hemisections remains intact for at least 2–3 months.This protocol is robust,straightforward to implement,and highly reproducible,offering a valuable tool for tissue architecture and cellular interaction studies. 展开更多
关键词 TRANSPARENT sections STRAIGHT
暂未订购
Automatic description of rock thin sections:A web application
7
作者 Stalyn Paucar Christian Mejia-Escobar Victor Collaguazo 《Artificial Intelligence in Geosciences》 2025年第1期228-239,共12页
The identification and characterization of rock types is a core activity in geology and related fields,including mining,petroleum,environmental science,industry,and construction.Traditionally,this task is performed by... The identification and characterization of rock types is a core activity in geology and related fields,including mining,petroleum,environmental science,industry,and construction.Traditionally,this task is performed by human specialists who analyze and describe the type,composition,texture,shape,and other properties of rock samples,whether collected in-situ or prepared in a laboratory.However,the process is subjective,dependent on the specialist’s experience,and time-consuming.This study proposes an artificial intelligence-based approach that combines computer vision and natural language processing to generate both textual and verbal descriptions from images of rock thin sections.A dataset of images and corresponding textual descriptions is used to train a hybrid deep learning model.Features extracted from the images using EfficientNetB7 are processed by a Transformer network to generate textual descriptions,which are then converted into verbal responses using a speech synthesis service.The experimental results show an accuracy of 0.892 and a BLEU score of 0.71.This model offers potential utility for research,professional,and academic applications and has been deployed as a web application for public use. 展开更多
关键词 ROCKS Thin sections Artificial intelligence Deep learning TRANSFORMER
在线阅读 下载PDF
HTML5与CSS3在网页前端设计优化中的应用研究
8
作者 刘靓丽 《电脑知识与技术》 2025年第22期51-53,共3页
随着互联网技术飞速发展,网页前端设计在信息传递与交互体验中扮演不可或缺的角色。传统网页设计由于静态布局及兼容性问题,难以满足现代多设备及交互需求。而HTML5和CSS3是现代Web前端开发的主流技术,极大提升了网页设计的语义化、适... 随着互联网技术飞速发展,网页前端设计在信息传递与交互体验中扮演不可或缺的角色。传统网页设计由于静态布局及兼容性问题,难以满足现代多设备及交互需求。而HTML5和CSS3是现代Web前端开发的主流技术,极大提升了网页设计的语义化、适配性与交互性。文章系统阐述HTML5与CSS3的特点,及在网页前端设计中的应用,从布局技术、响应式设计和高级功能优化等方面,探讨了HTML5与CSS3在Web前端优化中的实际运用,以期提高浏览网页用户的体验。 展开更多
关键词 HTML5 css3 Web前端 设计优化 高级应用
在线阅读 下载PDF
Absolute Cross Sections for Direct and Dissociative Ionizations of Oxygen Molecule Measured by 350-8000 eV Electron Impact
9
作者 Weizhe Huang Taj Wali Khan +3 位作者 Yuting Zhang Enliang Wang Xu Shan Xiangjun Chen 《Chinese Journal of Chemical Physics》 2025年第2期164-171,I0039,共9页
The direct and dissociative ionizations of oxygen molecule are investigated experimen-tally by electron collision with energies from 350 eV to 8000 eV.The absolute ionization cross sections for the product ions(O_(2)^... The direct and dissociative ionizations of oxygen molecule are investigated experimen-tally by electron collision with energies from 350 eV to 8000 eV.The absolute ionization cross sections for the product ions(O_(2)^(2+),O_(2)^(2+)O^(+),O^(2+),and their total)and two Coulomb explosion channels(O^(+)+O^(+)and O^(2+)+O^(+))are obtained by putting the data of O^(2+)on the scale of Ar+from O_(2)and Ar gases mixed with a fixed relative flow ratio of 1:1.The experimental errors are assessed by taking uncertainties of various factors into account.The present absolute cross sections are well consistent with the previous data in the overlapped energy range below 1000 eV. 展开更多
关键词 Electron collision Absolute ionization cross section Oxygen molecule
在线阅读 下载PDF
首届CSS体视学挑战赛启动筹备,青年实战舞台即将揭幕
10
《中国体视学与图像分析》 2025年第3期339-339,共1页
中国体视学学会智能成像分会联合有方医疗科技有限公司共同发起首届“CSS体视学挑战赛”,目前赛事已完成命题设计、数据合规与伦理审查、数据托管平台搭建及竞赛规则制定,进入倒计时阶段。挑战赛旨在为青年人才搭建实战舞台,发现和储备... 中国体视学学会智能成像分会联合有方医疗科技有限公司共同发起首届“CSS体视学挑战赛”,目前赛事已完成命题设计、数据合规与伦理审查、数据托管平台搭建及竞赛规则制定,进入倒计时阶段。挑战赛旨在为青年人才搭建实战舞台,发现和储备体视学后备力量。 展开更多
关键词 青年人才 实战舞台 css体视学挑战赛
原文传递
Automatic classification of Carbonatic thin sections by computer vision techniques and one-vs-all models
11
作者 Elisangela L.Faria Rayan Barbosa +7 位作者 Juliana M.Coelho Thais F.Matos Bernardo C.C.Santos J.L.Gonzalez Clécio R.Bom Márcio P.de Albuquerque P.J.Russano Marcelo P.de Albuquerque 《Artificial Intelligence in Geosciences》 2025年第1期271-281,共11页
Convolutional neural networks have been widely used for analyzing image data in industry,especially in the oil and gas area.Brazil has an extensive hydrocarbon reserve on its coast and has also benefited from these ne... Convolutional neural networks have been widely used for analyzing image data in industry,especially in the oil and gas area.Brazil has an extensive hydrocarbon reserve on its coast and has also benefited from these neural network models.Image data from petrographic thin section can be essential to provide information about reservoir quality,highlighting important features such as carbonate lithology.However,the automatic identification of lithology in reservoir rocks is still a significant challenge,mainly due to the heterogeneity that is part of the lithologies of the Brazilian pre-salt.Within this context,this work presents an approach using one-class or specialist models to identify four classes of lithology present in reservoir rocks in the Brazilian pre-salt.The proposed methodology had the challenge of dealing with a small number of images for training the neural networks,in addition to the complexity involved in the analyzed data.An auto-machine learning tool called AutoKeras was used to define the hyperparameters of the implemented models.The results found were satisfactory and presented an accuracy greater than 70%for image samples belonging to other wells not seen during the model building,which increases the applicability of the implemented model.Finally,a comparison was made between the proposed methodology and multiple-class models,demonstrating the superiority of one-class models. 展开更多
关键词 Carbonate thin section Convolution neural network Computational vision One-vs-all models
在线阅读 下载PDF
Spin-Orbit State-Resolved Differential Cross Sections of S(^(1)D)+HD Reaction
12
作者 Yu Li Heilong Wang +3 位作者 Zhirun Jiao Hongtao Zhang Chunlei Xiao Xueming Yang 《Chinese Journal of Chemical Physics》 2025年第5期582-586,I0147,共6页
Here,we report the spin-orbit state-resolved differential cross sections(DCSs)for the prototype barrierless reaction S(^(1)D)+HD.Both product channels,namely H+SD(^(2)Π_(3/2,1/2))and D+SH(^(2)Π_(3/2,1/2)),were measu... Here,we report the spin-orbit state-resolved differential cross sections(DCSs)for the prototype barrierless reaction S(^(1)D)+HD.Both product channels,namely H+SD(^(2)Π_(3/2,1/2))and D+SH(^(2)Π_(3/2,1/2)),were measured by high-resolution crossed molecular beam experiments.The DCSs of the two product channels show an overall forward-backward symmetry,in accordance with statistical model predictions.However,the DCSs for different spin-orbit manifolds show different preferences in forward or backward scattering directions at the same collision energies.This study reveals that,even though the title reaction proceeds via the long-lived complex mechanism,the spin-orbit coupling effects in the product channels play an important role in the reaction process. 展开更多
关键词 Barrierless reaction Spin-orbit effects Crossed molecular beam Differential cross sections
在线阅读 下载PDF
Investigations of inelastic cross sections of H_(2)O molecule by He^(2+) and C^(6+) projectiles with energy range around the Bragg peak
13
作者 Guo-Zhuang Li Cheng-Ye Sun +5 位作者 Rui Cheng Yan-Shi Zhang Liang-Wen Chen Sheng Zhang Xin-Xia Li Lei Yang 《Nuclear Science and Techniques》 2025年第2期141-154,共14页
Inelastic collisions are the dominant cause of energy loss in radiotherapy.In the energy range around the Bragg peak,single ionization(SI)and single-electron capture(SC)are the primary inelastic collisions that lead t... Inelastic collisions are the dominant cause of energy loss in radiotherapy.In the energy range around the Bragg peak,single ionization(SI)and single-electron capture(SC)are the primary inelastic collisions that lead to energy loss.This study employs the classical trajectory Monte Carlo method to study the SI and SC processes of H_(2)O molecules using He^(2+) and C^(6+) projectiles in the energy range of 10 keV/u to 10 MeV/u.The total cross sections,single differential cross sections,impact parameter dependence of SI and SC,and fragmentation cross sections were investigated.Results illustrate that the cross section for SI is the highest when the projectile energy is close to the Bragg peak energy.When the projectile energy is below the Bragg peak energy,the ionized electrons in the forward direction dominate,and the removal of electrons can be associated with large impact parameters.As the projectile energy increases,the emission angle of the electrons gradually transitions from small angles(60°~120°)to large angles(60°~120°),and the removal of electrons is associated with small impact parameters.The energy distributions of the ionized electron are similar when the projectile energy is equal to,below or above the Bragg peak energy.The fragmentation cross sections after SI and SC in the energy range around the Bragg peak were also estimated. 展开更多
关键词 Classical trajectory Monte Carlo Heavy ion-water molecule collision Inelastic cross sections
在线阅读 下载PDF
New measurement of ^(165)Ho neutron capture cross sections
14
作者 Su-Ya-La-Tu Zhang Yong-Shun Huang +7 位作者 Wei Jiang Jie Ren Rui-Rui Fan De-Xin Wang Chun-Lei Zhang Guo Li Dan-Dan Niu Mei-Rong Huang 《Nuclear Science and Techniques》 2025年第9期1-8,共8页
The neutron capture cross section for^(165)Ho was measured at the backstreaming white neutron beam line(Back-n)of the China Spallation Neutron Source(CSNS)using total energy detection systems,composed of a set of four... The neutron capture cross section for^(165)Ho was measured at the backstreaming white neutron beam line(Back-n)of the China Spallation Neutron Source(CSNS)using total energy detection systems,composed of a set of four C_(6)D_(6)scintillator detectors coupled with pulse height weighting techniques.The resonance parameters were extracted using the multilevel multichannel R-matrix code SAMMY to fit the measured capture yields of the^(165)Ho(n,γ)reaction in the neutron energy range below100 eV.Subsequently,the resonance region’s capture cross sections were reconstructed based on the obtained parameters.Furthermore,the unresolved resonance average cross section of the^(165)Ho(n,γ)reaction was determined relative to that of the standard sample^(197)Au within the neutron energy range of 2 keV to 1 MeV.The experimental data were compared with the recommended nuclear data from the ENDF/B-VIII.0 library,as well as with results of calculations performed using the TALYS-1.9 code.The comparison revealed agreement between the measured^(165)Ho(n,γ)cross sections and these data.The present results are crucial for evaluating the^(165)Ho neutron capture cross section and thus enhance the quality of evaluated nuclear data libraries.They provide valuable guidance for nuclear theoretical models and nuclear astrophysical studies. 展开更多
关键词 HOLMIUM Neutron capture reaction Cross section Total energy detection principle C6D6 scintillator detector China Spallation Neutron Source
在线阅读 下载PDF
基于CSS及边缘计算的移动医疗设备定位管理系统研究 被引量:22
15
作者 戴丽 袁琴 +2 位作者 朱顶贵 王增香 赵俊 《电子器件》 CAS 北大核心 2021年第1期192-196,共5页
满足移动医疗设备的区域性定位、运行轨迹跟踪及现场可视化管理需求,实现重点区域的越界和入侵告警管理。基于CSS技术和边缘计算技术,设计医疗设备定位管理系统,定义系统层次功能,优化定位滤波算法,构建实验测试系统并完成系统性能测试... 满足移动医疗设备的区域性定位、运行轨迹跟踪及现场可视化管理需求,实现重点区域的越界和入侵告警管理。基于CSS技术和边缘计算技术,设计医疗设备定位管理系统,定义系统层次功能,优化定位滤波算法,构建实验测试系统并完成系统性能测试。经过Kalman滤波后,系统定位精度可提高到1 m左右,传输速率为1 Mbit/s信号。在1μW功率下,传输距离可达5 m,在6.3 mW功率下,传输距离可达26 m。所设计方案可实现覆盖大范围区域的移动医疗设备的智能追踪,及时、准确地将各个区域设备的动态情况反映到中心监控平台,使管理人员能够随时掌握布控区域设备的分布状况和每个受控对象的运动轨迹,进而实现更加合理的管理。 展开更多
关键词 css 边缘计算 医疗设备 定位管理
在线阅读 下载PDF
TMSR CSS集成开发工具软件的实现与应用 被引量:16
16
作者 郭冰 张宁 +2 位作者 徐海霞 韩利峰 陈永忠 《核技术》 CAS CSCD 北大核心 2013年第11期66-70,共5页
CSS(Control System Studio)是一个以Eclipse RCP(Rich Client Platform)为框架结构,由多个应用程序以插件的形式组成的跨平台集成开发工具软件。它由美国SNS、BNL和德国DESY合作开发而成,但目前的CSS并不能满足钍基熔盐堆核能系统(TMSR... CSS(Control System Studio)是一个以Eclipse RCP(Rich Client Platform)为框架结构,由多个应用程序以插件的形式组成的跨平台集成开发工具软件。它由美国SNS、BNL和德国DESY合作开发而成,但目前的CSS并不能满足钍基熔盐堆核能系统(TMSR)控制系统的需要,如选用的关系型数据库和应用的软件工具不同。TMSR CSS主要是以Basic EPICS CSS源代码为基础并对其进行修改及扩展,集成了PostgreSQL关系型数据库、报警系统BEAST(Best Ever Alarm System Toolkit)等,可用于控制系统界面开发、报警及数据存档等,目前已应用于TMSR控制棒驱动机构(CRDM)控制系统样机中,但软件的可靠性还有待进一步确认和验证。 展开更多
关键词 TMSR css(Control System Studio) Eclipse RCP(Rich CLIENT Platform) 控制系统
原文传递
重力波与低纬高原地区M_β CSs地域特征的关系 被引量:12
17
作者 朱莉 丁治英 +1 位作者 张腾飞 李华宏 《大气科学学报》 CSCD 北大核心 2010年第5期561-568,共8页
利用MM5(V3.6)模式对2003年6月低纬高原地区一次大暴雨过程进行了数值模拟和地形敏感性试验,从重力波的角度研究低纬高原地区MβCSs生命史较短这一地域特征形成的原因。分析表明,大气稳定层结利于重力波的产生和传播,重力波的传播导致M... 利用MM5(V3.6)模式对2003年6月低纬高原地区一次大暴雨过程进行了数值模拟和地形敏感性试验,从重力波的角度研究低纬高原地区MβCSs生命史较短这一地域特征形成的原因。分析表明,大气稳定层结利于重力波的产生和传播,重力波的传播导致MβCSs的能量向两侧快速频散,使得成熟的MβCSs主体强度减弱,两侧有新的MβCSs生成并发展,中心降水也迅速减弱。地形敏感性试验表明,低纬高原地形使得大气在不稳定能量积累以后很快释放触发强降水,大气随即转化为稳定层结,利于重力波的快速传播和MβCSs主体能量的迅速频散,使得低纬高原地区触发暴雨的MβCSs生命史较短,引发的降水具有突发性强、历时短的特征。 展开更多
关键词 重力波 css地域特征 数值模拟 地形作用
在线阅读 下载PDF
基于细观结构与集成学习的岩石可钻性智能预测方法
18
作者 陈雁 孙远秋 +3 位作者 蒋增政 石祥超 王骞 陈帅 《岩矿测试》 北大核心 2026年第1期204-219,共16页
岩石可钻性作为衡量岩石破碎难易程度的重要指标,对指导钻探活动及开采深部底层具有重要意义。微钻法等常见的物理测定法,存在数据获取成本高、效率低及专业依赖度高等问题,现有研究中的数值预测法参数有限、精度较低。岩石细观结构在... 岩石可钻性作为衡量岩石破碎难易程度的重要指标,对指导钻探活动及开采深部底层具有重要意义。微钻法等常见的物理测定法,存在数据获取成本高、效率低及专业依赖度高等问题,现有研究中的数值预测法参数有限、精度较低。岩石细观结构在揭示岩石物理化学特性时发挥着重要作用,其与岩石力学参数如岩石可钻性有密切关系。为解决现有方法测定岩石可钻性的局限性,本文基于岩石学提出涵盖21个细观结构参数的岩石薄片颗粒特征集,并通过图像学与深度学习方法构建细观结构参数计算模型,通过Pearson、PCA分析方法实现特征优选,利用集成学习Stacking策略建立岩石可钻性预测模型。结果表明:①研究样本的岩石颗粒细观结构表征与可钻性呈现出较明显相关性,其中颗粒最短轴方差与面积标准差与岩石可钻性相关性最高,分别达0.42、0.37;②集成学习优化的融合模型预测能力最佳,E_(MAPE)、APE误差仅为14.1%、12.6%,较最优基准单模型分别降低4.7%、2.5%;③所提出方法能够提高测定可钻性效率,在1 min之内即可完成整个薄片细观结构计算及岩石可钻性预测;④本文模型可通过进一步扩充样本多样性,以提升在不同岩石细观特征下的可钻性识别性能。本文提供的岩石可钻性智能化评价方法,有效地揭示了细观结构与可钻性之间的关系,可为实时钻井工具选择和钻井参数优化提供高效支撑。 展开更多
关键词 岩石可钻性 集成学习 致密砂岩 岩石薄片 机器学习 模型融合
在线阅读 下载PDF
核磁共振碳谱研究:烷烃化学位移和(CSS)与分子路径指数矢量(VPM) 被引量:6
19
作者 夏之宁 余般梅 +4 位作者 袁晓燕 莫立宇 何萍 邓益群 李志良 《波谱学杂志》 CAS CSCD 北大核心 1999年第3期243-254,共12页
系统研究了核磁共振碳谱和化学位移规律及其定量构谱关系(QSSR).本文研究了一组十元素分子路径指数矢量VPM,并发现它与烷烃化学位移和CCS有良好线性相关性.采用多元线性回归进行准确估计与预测,结果优良.
关键词 核磁共振波谱 化学位移和 css VPM 烷烃
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部