检索结果-南通市图书馆

Biological sources, paleoenvironment, and organic matter enrichment in source rocks of the Ordovician Majiagou Formation, Ordos Basin, China:Evidence from biomarkers,microfossils, and inorganic geochemical analyses

引用

Journal of Palaeogeography 2024年第1期13卷 92-115页

作者： Jing-Jing Cao wen-Zhe gang Shang-Ru Yang State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Bejing)Beijing 102249China College of Geosciences China University of Petroleum(Bejing)Beijing 102249China Oil and Gas Technology Research Institute PetroChina Changqing Oifield CompanyXi'an 710018Shaanxi ProvinceChina

Carbonate deposits in the Ordovivian Majiagou Formation are significant source rocks for natural gas generation in the Ordos Basin, northwestern China. Previous studies mainly focused on the organic matter enrichment mechanism of shales rather than carbonate rocks. The biological sources and paleoenvironment of carbonate source rocks, and the main controlling factors of organic matter enrichment in the carbonate source rocks were studied in this paper in combination with evidence from biomarkers, microfossils and inorganic geochemistry analysis. The results show that four types of microfacies were identified in the Majiagou Formation, respectively as: mud flat microfacies, mud-dolomite flat microfacies, dolomite flat microfacies, and open marine microfacies. The biological sources of organic matter are chiefly planktonic algae, followed by bacteria. The mud flat and mud-dolomite flat contain a high abundance of terrigenous detrital inputs, as indicated by the high content of Al_(2)O_(3), TiO_(2), Th, and Zr. The low Sr/Cu and high Rb/Sr values reveal warm and humid paleoclimate conditions in the mud flat and mud-dolomite flat, whereas the dolomite flat and open marine were likely formed in hot and arid paleoclimate conditions. The mud flat and mud-dolomite flat deposits were characterized by high paleoproductivity of the Majiagou Formation. Low Sr/Ba values were found in the mud flat samples, indicating fresh to brackish water condition, whereas samples of other facies have a relatively high degree of salinity. Based on U_(auth), Mo_(auth), Cr_(auth), Co_(auth), δCe, and δEu values, the mud flat microfacies was formed in a suboxic and anoxic environment, whereas the mud-dolomite flat, dolomite flat and open marine microfacies were within dysoxic to oxic conditions. A model of organic matter enrichment in the Majiagou Formation is thus established. The level of terrigenous detrital inputs is the principal factor of organic matter enrichment in the Majiagou Formation,

关键词： Biological source Microfacies Trace elements Organic matter Majiagou Formation Ordos Basin

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

FaultMonitoring Strategy for PV System Based on I-V Feature Library

引用

Energy Engineering 2024年第3期121卷 643-660页

作者： Huaxing Zhao Yanbo Che gang wen Yijing Chen School of Electrical and Information Engineering Tianjin UniversityTianjin300000China State Grid Shuozhou Electric Power Supply Company Shuozhou036000China China Huaneng Clean Energy Research lnstitute Technology Co. Ltd.Beijing102209China

Long-term use in challenging natural conditions is possible for photovoltaic modules,which are extremely prone to *** to diagnose and address faults in Photovoltaic(PV)power systems in a timely manner can cause permanent damage to PV modules and,in more serious cases,***,research into photovoltaic module defect detection techniques is crucial for the growth of the photovoltaic sector as well as for maintaining national economic prosperity and ensuring public *** the drawbacks of the current real-time and historical data-based methods for monitoring distributed PV systems,this paper proposes a method for monitoring PV systems at the module or string level that can be achieved by monitoring only electrical *** approach doesn’t need a lot of tests to get the operational data of PV modules beforehand and only requires theoretical feature libraries of PV modules through panel parameter *** present operating conditions and the open-circuit and short-circuit faults can be precisely identified by comparing the observed open-circuit voltage and short-circuit current with the corresponding data in the theoretical feature *** that,by comparing the measured maximum power point voltage and current with the corresponding data in the theoretical feature library through the threshold method,aging and shadowing faults can be accurately *** testing was done to see whether the suggested method was *** results show that the proposed technique is able to diagnose open-circuit faults,short-circuit faults,aging faults,and shadowing faults with shadow occlusion above 20%.

关键词： PV system lambert W function threshold method

来源：

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

Energy partition in laser-induced cavitation bubbles near the rigid wall with a gas-containing hole

引用

Journal of Hydrodynamics 2024年第3期36卷 435-443页

作者： Dong-qiao He Hai-gang wen Si-yuan Geng Chen-xi Yang Qiang Zhong Zhi-feng Yao College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China PowerChina Beijing Engineering Corporation Limited Beijing100024China State Key Laboratory of Efficient Utilization of Agricultural Water Resources Beijing100083China Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System China Agricultural UniversityBeijing100083China

To investigate the energy partition in laser-induced cavitation bubbles near the rigid wall with a gas-containing hole,we utilized a nanosecond resolution photography system based on a Q-switched Nd:YAG laser and conventional industrial camera to carefully observe the transient process of bubble collapse near the rigid wall with a gas-containing *** analyzed the generation of collapse microjets and the emission of collapse shock *** found that the cavitation bubble near the rigid wall with a gas-containing hole collapsed at different times and space,and produced various types of shock *** on the far field pressure information of the shock waves measured by hydrophone,the energy of the shock waves generated by the bubble collapse near the rigid wall with a gas-containing hole is calculated for the first *** results show that the ratio of collapse shock wave energy to bubble energy is approximately between 0.7 and 0.8.

关键词： Energy partition bubble collapse laser-induced shock wave gas-containing hole

来源：

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

Elevated nitrogen and co-evolution history with competitors shape the invasion process of Galinsoga quadriradiata

引用

Journal of Plant Ecology 2024年第4期17卷 9-22页

作者： wen-gang Zhang Xing-Jiang Song Laís Petri gang Liu Xiao-Yan Chen Rui-Ling Liu Fang-Fang Huang Jia-Bin Zou Zhi-Hong Zhu College of Life Sciences Shaanxi Normal UniversityXi’an 710119China School for Environment and Sustainability University of MichiganAnn ArborMI 48109USA Research Center for UAV Remote Sensing Shaanxi Normal UniversityXi’an 710119China Changqing Teaching&Research Base of Ecology Shaanxi Normal UniversityXi’an 710119China Guangdong Provincial Key Laboratory of Silviculture Protection and UtilizationGuangdong Academy of ForestryGuangzhou 510520China

Invasive plants usually experience population differentiation as they expand from their initial invasive range to the ***,invasive plants usually encounter competitors which shared different co-evolutionary histories with *** factors may lead to varying responses of invasive plant populations to elevated nitrogen deposition during ***,this issue has received limited attention in prior *** address these challenges,we conducted a greenhouse experiment to investigate how population differentiation of Galinsoga quadriradiata interacts with the presence of various competitors in response to increased nitrogen *** types(new or old that shared short or long co-evolutionary history with the invader,respectively)were set to compete with the invasive central and edge populations under different nitrogen addition *** from the central population of ***,originating from the initial invasion range,showed greater total mass,reproduction and interspecific competitiveness compared with the edge *** addition improved growth and reproductive performance in both populations,and the central population had a stronger response compared with the edge *** performance of *** was inhibited more effectively by old competitors than new *** results indicate that population differentiation occurs in terms of growth and competitiveness during the range expansion of ***,with the central population exhibiting superior ***-evolutionary history with competitors is considered unfavorable for invasive plants in this *** results highlight the combined effects of population differentiation in invasive species and their co-evolution history with competitors in the context of global change factors.

关键词： Galinsoga quadriradiata central population edge population interspecific competition population differentiation elevated nitrogen

来源：

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

Autophagy and its role in gastrointestinal diseases

引用

World Journal of Gastroenterology 2024年第36期30卷 4014-4020页

作者： Bo-Zong Shao wen-gang Zhang Zhen-Yu Liu En-Qiang Linghu Department of Gastroenterology First Medical Center of Chinese People’s Liberation Army General HospitalBeijing 100853China

Gastrointestinal disorders encompass a spectrum of conditions affecting various organs within the digestive system,such as the esophagus,stomach,colon,rectum,pancreas,liver,small intestine,and bile *** role of autophagy in the etiology and progression of gastrointestinal diseases has garnered significant *** paper seeks to evaluate the impact and mechanisms of autophagy in gastrointestinal disorders by synthesizing recent research ***,we delve into inflammation-related gastrointestinal conditions,including ulcerative colitis,Crohn’s disease,and pancreatitis,as well as gastrointestinal cancers such as esophageal,gastric,and colorectal ***,we provide commentary on a recent publication by Chang et al in the World Journal of *** objective is to offer fresh perspectives on the mechanisms and therapeutic approaches for these gastrointestinal *** review aims to offer new perspectives on the mechanisms and therapeutic strategies for gastrointestinal disorders by critically analyzing relevant *** discussed,the role of autophagy in gastrointestinal diseases is complex and,at times,*** harness the full therapeutic potential of autophagy in treating these conditions,more in-depth research is imperative.

关键词： Autophagy Inflammation Cancer Inflammatory bowel disease Pancreatitis

来源：

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

The Bright Single Pulse Emission from PSR B1133+16

引用

Research in Astronomy and Astrophysics 2024年第4期24卷 253-261页

作者： Jun Tan Zhi-gang wen Zhen Wang Xue-Feng Duan Hong-Guang Wang Na Wang Vishal Gajjar Jian-Ping Yuan Rai Yuen wen-Ming Yan Jian-Ling Chen Wei Han Hui Wang Cheng-Bing Lyu Ai-Jun Dong Maths and Information Technology School Yuncheng UniversityYuncheng 044000China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Xinjiang Key Laboratory of Radio Astrophysics Urumqi 830011China School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China Space Science Laboratory University of CaliforniaBerkeley 94710USA Department of Physics and Electronic Engineering Yuncheng UniversityYuncheng 044000China School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550025China

We have conducted a comprehensive investigation into the bright single pulse emission from PSR B1133+16using the Giant Metrewave Radio *** time resolution data(61μs)were obtained at a center frequency of 322 MHz with a bandwidth of 32 MHz over a continuous observation period of 7.45 hr.A total of 1082 bright pulses were sporadically detected with peak flux densities ranging from 10 to 23 times stronger than the average pulse ***,no giant pulse-like emission with a relative pulse energy larger than 10 and extremely short duration was detected,indicating that these bright pulses cannot be categorized as giant pulse *** majority of these bright pulses are concentrated in pulse phases at both the leading and trailing windows of the average pulse profile,with an occurrence ratio of approximately *** pulse energy distribution for all individual pulses can be described by a combination of two Gaussian components and a cutoff power-law with an index of α=-*** updated nulling fraction of 15.35%±0.45% was determined from the energy *** emission of individual pulses follows a log-normal distribution in peak flux density *** is imperative that regular phase drifting in bright pulse sequence is identified in both the leading and trailing components for the first *** physical mechanisms are discussed in detail to provide insights into these observations.

关键词： (stars:)pulsars:general (stars:)pulsars:individual(PSR B1133+16) methods:observational methods:data analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

采用变滞环PWM的开关磁阻电机直接瞬时转矩控制方法

引用

机械科学与技术 2024年第5期43卷 858-864页

作者：张文港张小平湖南科技大学海洋矿产资源探采装备与安全技术国家地方联合工程实验室湖南湘潭411201 湖南科技大学信息与电气工程学院湖南湘潭411201

针对基于传统直接瞬时转矩控制的开关磁阻电机因采用固定滞环控制而存在转矩脉动仍然较大的问题,提出一种基于变滞环PWM的直接瞬时转矩控制方法。通过确定开关磁阻电机各相对应的工作区间,建立各区间相应的滞环函数并对函数中各参数进... 详细信息

针对基于传统直接瞬时转矩控制的开关磁阻电机因采用固定滞环控制而存在转矩脉动仍然较大的问题,提出一种基于变滞环PWM的直接瞬时转矩控制方法。通过确定开关磁阻电机各相对应的工作区间,建立各区间相应的滞环函数并对函数中各参数进行优化,根据所得优化后的滞环函数及开关磁阻电机当前转子位置角以及相应的转矩偏差,提出采用变滞环PWM控制方法对其功率变换电路中相应功率开关进行控制,以达到对其转矩脉动进行抑制的目的,最后对其效果进行了仿真验证,同时与传统基于固定滞环的直接瞬时转矩控制方法进行了对比分析,结果表明:该方法不仅显著降低了开关磁阻电机的转矩脉动,而且有效提高了其运行效率,因而具有较好的应用价值。

关键词：开关磁阻电机直接瞬时转矩控制变滞环函数转矩脉动抑制

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

黄阁西互通方案设计及匝道交织区分析计算

引用

公路 2024年第7期69卷 54-60页

作者：盛萍许文刚中交第二公路勘察设计研究院有限公司武汉市430056

狮子洋通道工程黄阁西互通的初测、初步设计、施工图设计工作已顺利开展。基于此,现对该立交方案比选设计、施工图设计的经验进行总结分析。详细介绍了黄阁西立交方案的遴选与改进过程,并根据案例对匝道交织区进行分析计算,验证了方案... 详细信息

狮子洋通道工程黄阁西互通的初测、初步设计、施工图设计工作已顺利开展。基于此,现对该立交方案比选设计、施工图设计的经验进行总结分析。详细介绍了黄阁西立交方案的遴选与改进过程,并根据案例对匝道交织区进行分析计算,验证了方案的可行性,为类似立交方案设计、匝道布设调整与匝道交织计算提供参考。

关键词：狮子洋通道工程互通方案设计匝道布设的调整主匝道交织段通行能力计算

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

抗体修饰DNA测序酶的开发及其应用

引用

生物技术通报 2024年第5期40卷 84-93页

作者：宋辉曹文刚肖晓文杜军北京擎科生物科技股份有限公司研究院北京100000 湖北擎科生物科技有限公司研发部鄂州436000

【目的】开发一种新型DNA测序酶,解决一代测序技术应对复杂DNA结构模板所面临的主要挑战,如测序信号中断或测序信号快速衰减。【方法】从NCBI数据库中挖掘到了Taq DNA聚合酶和单链结合蛋白SSB基因信息,利用遗传融合、定点突变及基因设... 详细信息

【目的】开发一种新型DNA测序酶,解决一代测序技术应对复杂DNA结构模板所面临的主要挑战,如测序信号中断或测序信号快速衰减。【方法】从NCBI数据库中挖掘到了Taq DNA聚合酶和单链结合蛋白SSB基因信息,利用遗传融合、定点突变及基因设计技术获得了一种新型的测序酶Sso-Sequenase。利用亲和层析和离子交换层析,获得了纯化的测序酶。利用抗体修饰技术改良了Sso-Sequenase的性能,并且利用STR技术对其热启动性能进行了表征。选取多组不同类型的复杂模板,采用一代技术对比分析了Sso-Sequenase测序酶试剂盒和传统BigDye测序试剂盒的测序表现。【结果】Sso-Sequenase在大肠杆菌中稳定表达,纯度达到95%以上,产量高达10.5 mg/L。当温度低于35℃时,Sso-Sequenase表现出热启动活性。在复杂模板的一代测序反应中,如重复序列、高GC和发夹结构等样本,Sso-Sequenase测序酶成功完成了所有样本的测序,序列的平均碱基质量QV大于20。相比而言,BigDye测序试剂盒在处理这些复杂样本时,多数样本测序信号出现了显著衰减或中断。【结论】开发了一种纯度好、产量高,兼具热启动活性的DNA测序酶Sso-Sequenase及测序试剂盒,显著提高了复杂DNA结构模板(重复序列、高GC和发夹结构)测序成功率。

关键词： DNA测序酶抗体修饰复杂模板测序

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于物理信息神经网络的盾构隧道诱发地表沉降预测

引用

工程力学 2024年第4期41卷 161-173页

作者：张子龙潘秋景仉文岗黄阜中南大学土木工程学院湖南长沙410075 中南大学隧地工程研究中心湖南长沙410075 重庆大学土木工程学院重庆400045 长沙理工大学土木工程学院湖南长沙410004

地表沉降是城市复杂环境下盾构隧道施工重点关注的问题。传统机器学习方法在预测隧道施工诱发地表沉降时忽略了其内在的物理机理,存在对训练样本需求量较大的弊端。基于深度神经网络(deep neural networks, DNN)对Verruijt-Booker解的... 详细信息

地表沉降是城市复杂环境下盾构隧道施工重点关注的问题。传统机器学习方法在预测隧道施工诱发地表沉降时忽略了其内在的物理机理,存在对训练样本需求量较大的弊端。基于深度神经网络(deep neural networks, DNN)对Verruijt-Booker解的围岩位移因子进行修正,构建地表沉降与隧道开挖面空间位置的关联。将修正后的Verruijt-Booker解的物理方程耦合至另一并行的DNN框架中,构建数据-物理双驱动的物理信息神经网络模型(physics-informed neural networks, PINN),从而约束神经网络在满足物理机制的空间中进行训练。算例分析的结果表明:在同等配置的条件下,提出的PINN模型的预测效果显著优于单一数据驱动的传统DNN模型,其外推泛化性能得到显著提升。工程应用的结果表明:PINN模型可以利用施工前期的实测数据,准确预测后续施工过程中开挖面在不同位置时监测断面的地表沉降值。提出的方法有助于提高盾构隧道施工过程中地表沉降控制的智慧化程度,可为工程的潜在风险及施工决策提供预警和指导。

关键词：盾构隧道地表沉降物理信息神经网络物理机理数据物理双驱动

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：