检索结果-南通市图书馆

Constraints of palaeoenvironment on organic matter of Benxi Formation shale and discussion on enrichment mechanism under different facies

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Frontiers of Earth Science 2024年第1期18卷 148-171页

作者： Qianyang HE Delu LI qiang SUN Jianwen GAO Haibin LI xinhu LI xiaochen ZHAO Shaofei WANG Gaozhe JI College of Geology and Environment Xi’an University of Science and TechnologyXi’an 710054China Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation Xi’an University of Science and TechnologyXi’an 710054China Geological Research Institute for Coal Green Mining Xi’an University of Science and TechnologyXi’an 710054China Research Institute of Exploration and Development PetroChina Changqing Oilfield CompanyXi’an 710018China School of Civil Engineering and Architecture Shaanxi University of TechnologyHanzhong 723001China

As a hydrocarbon-rich sedimentary basin in China,the Ordos Basin has enormous potential for shale gas *** shale of the Upper Carboniferous Benxi Formation is rich in organic matter,however,its palaeoenvironment and organic matter enrichment mode are yet to be *** this study,the geochemical characteristics of the shale of the Benxi Formation in the east-central part of the Ordos Basin were analyzed to investigate its *** the same time,the organic matter enrichment modes in different sedimentary facies were compared and *** results indicate that:1)the shale of the Benxi Formation was mainly deposited on the continental margin and strong terrestrial clastic input;2)the deposition period of the Benxi Formation shale had a hot and humid climate with high palaeoproductivity and local volcanic hydrothermal fluid,and a high sedimentation rate with the strong stagnant *** bottom water was in dysoxic conditions and a semi-saline deposition environment;3)multiple factors,such as palaeoproductivity,volcanic hydrothermal,redox conditions,and palaeosalinity interact to influence the enrichment of shale organic matter in Benxi Formation;4)the organic matter enrichment modes of continental,marine-continental transitional,and marine shales can be classified into three types:“production mode”,“hybrid mode of preservation and production”,and“preservation mode”,*** study provides a reference for the organic matter enrichment mode,shale gas formation conditions,and core area evaluation in these marine-continental transitional shales,and also offers new guidance for exploration ideas for shale gas in different sedimentary facies.

关键词： Benxi Formation shale palaeoenvironment organic matter enrichment facies

A multifunctional stealthy material for wireless sensing and active camouflage driven by configurable polarization

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2023年第1期132卷 42-49页

作者： Min Zhang Mao-Sheng Cao qiang-qiang Wang xi-xi Wang Wen-qiang Cao Hui-Jing yang Jie Yuan School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Department of Physics Beijing Technology and Business UniversityBeijing 100048China School of Electrical and Electronic Engineering Nanyang Technological University639798Singapore Department of Physics Tangshan Normal UniversityTangshan 063000China School of Information Engineering Minzu University of ChinaBeijing 100081China

The dipole species transformation and polarization relaxation configuration are achieved by changing the cobalt ion stoichiometry,which precisely tailors the electromagnetic attenuation performance of bismuth iron cobalt *** the stoichiometric ratio of Fe:Co is 19:1,the optimal reflection loss reaches-60 *** high electromagnetic attenuation performance significantly improve the linear sensitivity of the strain response and active customized stealth capability of the designed multifunctional capacitor-like ***,the wireless multifunctional design integrates energy attenuaten of electromagnetic wave with the wireless sensing and active camouflage functions for the first *** work provides an important step for the realization of electromagnetical multifunctional applications including electromag-netic protection and electromagnetic sensing in artificial beings,medical health and even space travel.

关键词： Electromagnetic absorption Polarization relaxation Electromagnetic sensing Active camouflage

基于纤维加固砂土静力液化评估的超孔隙压力系数研究

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

岩土力学 2024年第3期45卷 714-724页

作者：张希栋董晓强段伟谢明星太原理工大学土木工程学院山西太原030024 太原理工大学山西省土木工程防灾与控制重点实验室山西太原030024

纤维加固技术通过向土体中添加离散的抗拉纤维以改良土体的力学性能。通过对纤维加固疏松砂土开展不排水三轴压缩试验以分析其静力液化行为,并对比了不同超孔隙压力系数评估纤维加固砂土液化的可行性。试验结果表明,在不排水三轴压缩下... 详细信息

纤维加固技术通过向土体中添加离散的抗拉纤维以改良土体的力学性能。通过对纤维加固疏松砂土开展不排水三轴压缩试验以分析其静力液化行为,并对比了不同超孔隙压力系数评估纤维加固砂土液化的可行性。试验结果表明,在不排水三轴压缩下,疏松砂土对静力液化异常敏感,而纤维加固可以有效阻止疏松砂土发生静力液化。纤维显著改变了砂土骨架在不排水三轴压缩下的有效应力路径,从而影响其液化行为。基于有效应力原理定义的传统超孔隙压力系数ru在评估纤维加固砂土的液化时具有明显缺陷。有效超孔隙压力系数r_(u)’和骨架超孔隙压力系数r_(u)^(*)为纤维加固砂土的液化评估提供了更加合理的指标。借助基于混合物法则的本构模型框架,骨架超孔隙压力系数引入了纤维的应力贡献,揭示了纤维、砂土骨架以及孔隙水的荷载分担机制。当r_(u)^(*)=1时,砂土骨架的有效平均应力减小为0,纤维加固砂土发生液化。

关键词：纤维加固砂土液化纤维应力超孔隙压力系数

Identification　method　of　weak　seismic　phases　on　the　basis　of　wavelet　packet　trans-form

在线全文

学校读者我要写书评

暂无评论

Acta Seismologica Sinica(English Edition) 1998年第4期11卷 431-439页

作者： xi-qiang Liui (1) (2) Hui-Lan Zhou (1) Zhi-Zhen Zheng (3) Ping Shen (4) Xuan-Hui yang (3) Yan-Lu Ma (1) 1. Graduate School University of Science and Technology of China 100039 Beijing China 2. Seismological Bureau of Shandong Province 250014 Ji’nan China 3. Center for Earthquake Data and Information China Seismological Bureau 100045 Beijing China 4. Institute of Geophysics China Seismological Bureau 100081 Beijing China

Ｉｄｅｎｔｉｆｉｃａｔｉｏｎｍｅｔｈｏｄｏｆｗｅａｋｓｅｉｓｍｉｃｐｈａｓｅｓｏｎｔｈｅｂａｓｉｓｏｆｗａｖｅｌｅｔｐａｃｋｅｔｔｒａｎｓ－ｆｏｒｍＸＩ－ＱＩＡＮＧＬＩＵ１）３）（刘希强）ＨＵＩ－ＬＡＮＺＨＯＵ１）（... 详细信息

Ｉｄｅｎｔｉｆｉｃａｔｉｏｎｍｅｔｈｏｄｏｆｗｅａｋｓｅｉｓｍｉｃｐｈａｓｅｓｏｎｔｈｅｂａｓｉｓｏｆｗａｖｅｌｅｔｐａｃｋｅｔｔｒａｎｓ－ｆｏｒｍＸＩ－ＱＩＡＮＧＬＩＵ１）３）（刘希强）ＨＵＩ－ＬＡＮＺＨＯＵ１）（周惠兰）ＺＨＩ－ＺＨＥＮＺＨＥＮＧ...

关键词： wavelet transform wavelet packet transform transient spectra analysis weak seismic phase discrimination

在线全文

学校读者我要写书评

暂无评论

航天器姿态受限的协同势函数族设计方法

自动化学报 2024年第1期50卷 54-65页

作者：岳程斐霍涛陈雪芹沈强曹喜滨哈尔滨工业大学(深圳)空间科学与应用技术研究院深圳518055 哈尔滨工业大学卫星技术研究所哈尔滨150001 上海交通大学航空航天学院上海200240

提出一种考虑航天器姿态约束的协同势函数设计方法,在姿态全局收敛的同时,保证姿态在机动过程中始终满足姿态约束.首先,建立航天器姿态指向约束模型,并针对每一个指向约束设计软约束区域;然后,基于“角度扰动”方法设计协同势函数族;接... 详细信息

提出一种考虑航天器姿态约束的协同势函数设计方法,在姿态全局收敛的同时,保证姿态在机动过程中始终满足姿态约束.首先,建立航天器姿态指向约束模型,并针对每一个指向约束设计软约束区域;然后,基于“角度扰动”方法设计协同势函数族;接着,通过设计协同势函数族内函数切换规律,在软约束区域内构建满足姿态约束的势函数,并给出区域内势函数临界点分布的调整方法;最后,将所得的势函数用于航天器的避障控制,以比例-微分控制为例,通过数值仿真,验证该方法的有效性.

关键词：航天器控制协同势函数姿态约束姿态控制三维特殊正交群

维普期刊数据库博看期刊

Different accretion and diagenetic patterns within the fabrics of the Permian–Triassic boundary microbialites on the Leye isolated carbonate platform, South China Block

在线全文

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2021年第2期10卷 197-208页

作者： xi-yang Zhang Yue Li Guan Wang Hong-qiang yang Key Laboratory of Ocean and Marginal Sea Geology South China Sea Institute of OceanologyInnovation Academy of South China Sea Ecology and Environmental EngineeringChinese Academy of SciencesGuangzhou 510301Guangdong ProvinceChina State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and PaleoenvironmentChinese Academy of SciencesNanjing 210008Jiangsu ProvinceChina.

A comprehensive study on the accretion and diagenesis of the Permian–Triassic boundary microbialites is conducive to a better understanding of the ecological community after the end-Permian mass extinction. Here we studied the special microbialite sequences at the Tianba section of Leye isolated carbonate platform, South China Block. The microbialites are shown as small columnar stromatolites, stromatolitic thrombolites, spotted thrombolites,and domical digitate thrombolites in an ascending order. Thin section analyses, coupled with cathodoluminescence photos and oxygen isotopic data, reveal that all types of microbially-mediated laminae/clots are partly *** of the Polybessurus-like fossils commonly occur in the recrystallized fabrics of stromatolitic laminae. However,the Polybessurus-like fossils are rare in quantity and generally fragmentary and structureless in stromatolitic clots and spotted clots. Such taphonomic features are likely interpreted as the early decomposition by heterotrophic bacteria in an oxygen-depleted microenvironment caused by rapid accumulations of organic matter in the calm *** enrichments of ~(13)C in the laminae of stromatolite and in the clots of stromatolitic thrombolite and spotted thrombolite than in adjacent interstitial matrixes signify the photosynthesis-dominated isotopic fractionation during the growth of microbial communities. Rare calcimicrobial structures but many calcite crystal fans were found in the ~(13)C-depleted digitate clots. These phenomena indicate that seawater on the carbonate platform was ~(12)C-enriched and supersaturated, accelerating carbonate precipitations and decompositions of organic matter within the microbial community. Different preservations of the Polybessurus-like fossil revealed the complicated microbiallydominated sedimentation and post-depositional diagenesis in the abnormal seawater after the catastrophe.

关键词： Microbialite Calcimicrobe Carbon isotope Diagenesis End-Permian mass extinction South China Block

Transient breathing dynamics during extinction of dissipative solitons in mode‑locked fiber lasers

在线全文

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2024年第1期17卷 9-19页

作者： Zichuan Yuan Si Luo Ke Dai xiankun Yao Chenning Tao qiang Ling Yusheng Zhang Zuguang Guan Daru Chen Yudong Cui Hangzhou Institute of Advanced Studies Zhejiang Normal UniversityHangzhou 311231China State Key Laboratory of Modern Optical Instrumentation College of Optical Science and EngineeringZhejiang UniversityHangzhou 310027China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China Key Laboratory of Optical Information Detection and Display Technology of Zhejiang Zhejiang Normal UniversityJinhua 321004China School of Physics Northwest UniversityXi’an 710127China

The utilization of the dispersive Fourier transformation approach has enabled comprehensive observation of the birth process of dissipative solitons in fiber ***,there is still a dearth of deep understanding regarding the extinction process of dissipative *** this study,we have utilized a combination of experimental and numerical techniques to thoroughly examine the breathing dynamics of dissipative solitons during the extinction process in an Er-doped mode-locked fiber *** results demonstrate that the transient breathing dynamics have a substantial impact on the extinction stage of both steady-state and breathing-state dissipative *** duration of transient breathing exhibits a high degree of sensitivity to variations in pump *** simulations are utilized to produce analogous breathing dynamics within the framework of a model that integrates equations characterizing the population inversion in a mode-locked *** results corroborate the role of Q-switching instability in the onset of breathing ***,these findings offer new possibilities for the advancement of various operational frameworks for ultrafast lasers.

关键词： Breathing soliton Fiber laser Dispersive Fourier transform Q-switched instability

Activatable fluorescent probes for imaging and diagnosis of rheumatoid arthritis

在线全文

学校读者我要写书评

暂无评论

Military Medical Research 2024年第2期11卷 287-307页

作者： Pan Luo Fu-qiang Gao Wei Sun Jun-You Li Cheng Wang Qing-Yu Zhang Zhi-Zhuo Li Peng Xu Department of Joint Surgery Honghui HospitalXi'an Jiaotong UniversityXi'an 710054China Department of Orthopedics China-Japan Friendship HospitalBeijing 100029China Department of Orthopaedic Surgery of the Perelman School of Medicine University of PennsylvaniaPhiladelphiaPA 19104USA School of Mechanical Engineering Sungkyunkwan UniversitySuwon 16419South Korea Department of Orthopaedic Surgery Peking University Third HospitalPeking UniversityBeijing 100191China Department of Orthopedics Shandong Provincial Hospital Affiliated to Shandong First Medical UniversityJinan 250021China State Key Laboratory of Pharmaceutical Biotechnology Division of Sports Medicine and Adult Reconstructive SurgeryDepartment of Orthopedic SurgeryNanjing Drum Tower Hospitalthe Affiliated Hospital of Nanjing University Medical SchoolNanjing 210008China

Rheumatoid arthritis(RA)is a systemic autoimmune disease that is primarily manifested as synovitis and polyarticular opacity and typically leads to serious joint damage and irreversible disability,thus adversely affecting locomotion ability and life ***,good prognosis heavily relies on the early diagnosis and effective therapeutic monitoring of *** fluorescent probes play vital roles in the detection and imaging of biomarkers for disease diagnosis and in vivo ***,we review the fluorescent probes developed for the detection and imaging of RA biomarkers,namely reactive oxygen/nitrogen species(hypochlorous acid,peroxynitrite,hydroxyl radical,nitroxyl),pH,and cysteine,and address the related challenges and prospects to inspire the design of novel fluorescent probes and the improvement of their performance in RA studies.

关键词： Rheumatoid arthritis Fluorescent probe Imaging Diagnosis Biomarker

基于遥感时-空-谱特征及随机森林模型的土壤重金属空间分布预测

在线全文

学校读者我要写书评

暂无评论

环境科学 2024年第3期45卷 1713-1723页

作者：王泽强张冬有徐夕博王兆鹏杨东宇宋晓宁哈尔滨师范大学地理科学学院哈尔滨150025 枣庄学院旅游与资源环境学院枣庄277160 北京师范大学地表过程与资源生态国家重点实验室北京100875

获取土壤重金属的含量特征及空间分布是预防土壤污染和制定环保政策的关键.选取济南市长清区为研究区,系统采集304处表层土壤样品(0~20 cm),利用多源遥感数据构建土壤重金属的光谱特征、时间特征和空间特征;进一步采用相关分析法选择出... 详细信息

获取土壤重金属的含量特征及空间分布是预防土壤污染和制定环保政策的关键.选取济南市长清区为研究区,系统采集304处表层土壤样品(0~20 cm),利用多源遥感数据构建土壤重金属的光谱特征、时间特征和空间特征;进一步采用相关分析法选择出与土壤重金属密切相关的时-空-谱特征,并将其作为输入自变量,实测土壤砷(As)含量值为因变量,建立基于随机森林(RF)算法的空间预测模型,完成土壤重金属的含量估算和空间分布预测.结果表明:(1)As含量均值超出背景值43.17%,低于农用地土壤污染风险规定的筛选值和管控值,表明As在土壤中出现富集,但处于可管控范围内.(2)在单个遥感特征构建的土壤重金属空间预测模型中,精度由高到低依次为:空间特征(RPIQ=3.87)>时间特征(RPIQ=2.57)>光谱特征(RPIQ=2.50),空间特征对土壤重金属空间预测最为重要.(3)基于“时间-空间”、“时间-光谱”和“空间-光谱”组合特征的土壤重金属空间预测模型均优于单个特征构建的模型,其精度系数RPIQ值分别为4.81、 4.21和4.70.(4)利用“时间-空间-光谱”特征组合输入的随机森林模型达到最佳的空间预测精度(R^(2)=0.90;RMSE=0.77;RPIQ=5.68).(5)As在空间分布上从西北到东南含量逐步降低,主要受到黄河冲淤积和工业活动影响.研究采用的遥感时-空-谱特征结合随机森林算法的土壤重金属空间预测技术,可为土壤污染防治及环境风险管控提供有效的方法支持.

关键词：土壤砷(As) 随机森林(RF) 遥感时-空-谱特征空间分布预测