检索结果-南通市图书馆

A novel algorithm for evaluating cement azimuthal density based on perturbation theory in horizontal well

Petroleum Science 2024年第1期21卷 244-251页

作者： ji-Lin Fan feng Zhang Qian Chen hao-Chen Song Lu-Yu Zhong Yue-Xiang Dai National Key Laboratory of Deep Oil and Gas School of GeosciencesChina University of Petroleum(East China)Qingdao 266580ShandongChina China National Logging Corporation Xi'an 710076ShaanxiChina Sinopec Matrix Corporation Qingdao 266001ShandongChina

Cement density monitoring plays a vital role in evaluating the quality of cementing projects,which is of great significance to the development of oil and ***,the presence of inhomogeneous cement distribution and casing eccentricity in horizontal wells often complicates the accurate evaluation of cement azimuthal *** this regard,this paper proposes an algorithm to calculate the cement azimuthal density in horizontal wells using a multi-detector gamma-ray detection *** spatial dynamic response functions are simulated to obtain the influence of cement density on gamma-ray counts by the perturbation theory,and the contribution of cement density in six sectors to the gamma-ray recorded by different detectors is obtained by integrating the spatial dynamic response *** with the relationship between gamma-ray counts and cement density,a multi-parameter calculation equation system is established,and the regularized Newton iteration method is employed to invert casing eccentricity and cement azimuthal *** approach ensures the stability of the inversion process while simultaneously achieving an accuracy of 0.05 g/cm^(3) for the cement azimuthal *** accuracy level is ten times higher compared to density accuracy calculated using calibration ***,this algorithm enhances the accuracy of cement azimuthal density evaluation,provides valuable technical support for the monitoring of cement azimuthal density in the oil and gas industry.

关键词： Cement azimuthal density Perturbation theory Casing eccentricity Spatial dynamic response function Regularized Newton iteration

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

Assessment and Enhancement of FRC of Power Systems Considering Thermal Power Dynamic Conditions

引用

CSEE Journal of Power and Energy Systems 2024年第4期10卷 1371-1383页

作者： feng Hong Yalei Pang Weiming ji Lu Liang Fang Fang Junhong hao jizhen Liu State Key Laboratory of Alternate Electric Power System with Renewable Energy Sources and School of Control and Computer Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Alternate Electric Power System with Renewable Energy Sources School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing 102206China

Frequency stability and security have been a vital challenge as large-scale renewable energy is integrated into power *** contrast,the proportion of traditional thermal power units decreases during the decarbonization transformation process,resulting in poor frequency *** paper aims to explore the potential of frequency regulation support,dynamic assessment,and capacity promotion of thermal power plants in the transition *** the dynamic characteristics of the main steam working fluid under different working conditions,a nonlinear observer is constructed by extracting the main steam pressure and valve opening degree *** real-time frequency modulation capacity of thermal power units can provide a dynamic state for the power grid.A dynamic adaptive modification for primary frequency control(PFC)of power systems,including wind power and thermal power,is proposed and *** power dynamic allocation factor is adaptively optimized by predicting the speed droop ratio,and the frequency modulation capability of the system is improved by more than 11%under extreme ***,through the Monte Carlo simulation of unit states of the system under various working conditions,the promotion of the frequency regulation capacity with high wind power penetration(WPP)is verified.

关键词： Dynamic evaluation frequency regulation power system predictive modeling wind penetration

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

Genomic and phenotypic signatures provide insights into the wide adaptation of a global plant invader

引用

Plant Communications 2024年第4期5卷 275-290页

作者： Yan hao Xin-feng Wang Yaolin Guo Tian-Yang Li ji Yang Malika LAinouche Armel Salmon Rui-Ting Ju ji-Hua Wu Lin-feng Li Bo Li National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary and Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering Institute of Biodiversity Science and Institute of Eco-ChongmingSchool of Life SciencesFudan UniversityShanghai 200438China State Key Laboratory of Biocontrol Guangdong Provincial Key Laboratory of Plant ResourcesSchool of Life SciencesSun Yat-sen UniversityGuangzhou 510275China UMR CNRS 6553 Universite´of RennesCampus de Beaulieu35042 Rennes Cedex ParisFrance State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems College of EcologyLanzhou UniversityLanzhou 730000China Ministry of Education Key Laboratory for Transboundary Ecosecurity of Southwest China Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology and Centre for Invasion BiologyInstitute of BiodiversitySchool of Ecology and Environmental ScienceYunnan UniversityKunmingYunnan 650504China

Invasive alien species are primary drivers of biodiversity loss and species *** cordgrass(Spartina alterniflora)is one of the most aggressive invasive plants in coastal ecosystems around the ***,the genomic bases and evolutionary mechanisms underlying its invasion success have remained largely ***,we assembled a chromosome-level reference genome and performed phenotypic and population genomic analyses between native US and introduced Chinese *** phenotypic comparisons showed that introduced Chinese populations have evolved competitive traits,such as earlyflowering time and greater plant biomass,during secondary introductions along China’s *** genomic and transcriptomic inferences revealed distinct evolutionary trajectories of low-and high-latitude Chinese *** particular,genetic mixture among different source populations,together with in-dependent natural selection acting on distinct target genes,may have resulted in high genome dynamics of the introduced Chinese *** study provides novel phenotypic and genomic evidence showing how smooth cordgrass rapidly adapts to variable environmental conditions in its introduced ***,candidate genes related toflowering time,fast growth,and stress tolerance(i.e.,salinity and submergence)provide valuable genetic resources for future improvement of cereal crops.

关键词： adaptation natural selection invasive species population genomics Spartina alterniflora hao Y. Wang X.-F. Guo Y. Li T.-Y. Yang J. Ainouche M.L. Salmon A. Ju R.-T. Wu J.-H. Li L.-F. and Li B.(2024).Genomic and phenotypic signatures provide insights into the wide adaptation of a global plant invader.

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

Review of Iron-Based Catalysts for Carbon Dioxide Fischer-Tropsch Synthesis

引用

Transactions of Tianjin University 2024年第2期30卷 178-197页

作者： ji-Yue jia Yu-Ling Shan Yong-Xiao Tuo hao Yan Xiang feng De Chen State Key Laboratory of Heavy Oil Processing China University of PetroleumQingdao 266580China College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266042China Department of Chemical Engineering Norwegian University of Science and Technology7491 TrondheimNorway

Capturing and utilizing CO_(2)from the production process is the key to solving the excessive CO_(2)emission problem. CO_(2)hydrogenation with green hydrogen to produce olefins is an effective and promising way to utilize CO_(2)and produce valuable chemicals. The olefins can be produced by CO_(2)hydrogenation through two routes, i.e., CO_(2)-FTS (carbon dioxide Fischer- Tropsch synthesis) and MeOH (methanol-mediated), among which CO_(2)-FTS has significant advantages over MeOH in practical applications due to its relatively high CO_(2)conversion and low energy consumption potentials. However, the CO_(2)-FTS faces challenges of difficult CO_(2)activation and low olefins selectivity. Iron-based catalysts are promising for CO_(2)-FTS due to their dual functionality of catalyzing RWGS and CO-FTS reactions. This review summarizes the recent progress on iron-based catalysts for CO_(2)hydrogenation via the FTS route and analyzes the catalyst optimization from the perspectives of additives, active sites, and reaction mechanisms. Furthermore, we also outline principles and challenges for rational design of high-performance CO_(2)-FTS catalysts.

关键词： CO_(2)hydrogenation Olefins CO_(2)-FTS Iron-based catalysts

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

Restricted Arc-Connectivity of Harary Digraphs

引用

Journal of the Operations Research Society of China 2024年第2期12卷 540-547页

作者： Jun-hao Zhang ji-Xiang Meng College of Mathematics and System Science Xinjiang UniversityUrumqi 830046XinJiangChina

The h-restricted arc-connectivity of a digraph is an important parameter to measure fault-tolerance of interconnection *** paper determines that the h-restricted arc-connectivity of the Harary digraph D=G(n;1,2,.:,k)i... 详细信息

关键词： Restricted arc-connectivity λ_(h)(D) Super-λ_(h) λ_(h)-Atom λ_(h)-Superatom

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

Reduced-size liver transplantation for glycogen storage disease

引用

Hepatobiliary & Pancreatic Diseases International 2009年第1期8卷 106-108页

作者： ji, hao-feng Wang, Wei-Lin Shen, Yan Zhang, Min Liang, Ting-Bo Wu, jian Xu, Xiao Yan, Sheng Zheng, Shu-Sen Zhejiang Univ Sch Med Affiliated Hosp 1 Dept Hepatobiliary Pancreat Surg Hangzhou 310003 Zhejiang Peoples R China

BACKGROUND: Glycogen storage disease (GSD) is an inherited metabolic disorder in which the concentration and/or structure of glycogen in tissues is abnormal. Essentially, abnormalities in all known enzymes involved in the synthesis or degradation of glycogen and glucose have been found to cause some type of GSD. Liver and muscle have abundant quantities of glycogen and are the most common and seriously affected tissues. This study was to assess reduced-size liver transplantation for the treatment of GSD. METHODS: The clinical data from one case of GSD type I with hepatic adenoma was retrospectively analyzed. The clinical manifestations were hepatomegaly, delayed puberty, growth retardation, sexual immaturity, hypoglycemia, and lactic acidosis, which made the young female patient eligible for reduced-size liver transplantation. RESULTS: The patient recovered uneventfully with satisfactory outcome, including 12 cm growth in height and 5 kg increase in weight during 16 months after successful reduced-size liver transplantation. She has been living a normal life for 4 years so far. CONCLUSIONS: Reduced-size liver transplantation is an effective treatment for GSD with hepatomegaly and hepatic adenoma. Delayed puberty, growth retardation, hypoglycemia and lactic acidosis can be cured by surgery.

关键词： reduced-size liver transplantation glycogen storage disease hepatic adenoma von Gierke's disease

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

Effects of phosphorus limitation on sinking velocities of phytoplankton during summer in the Changjiang River Estuary

引用

Acta Oceanologica Sinica 2024年第6期43卷 131-141页

作者： Xinchi You Qiang hao jie Zhu Wei Zhang Haiyan jin Dewang Li Huanhong ji Yu Ke feng Zhou Ocean College Zhejiang UniversityZhoushan 316021China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310000China Key Laboratory of Marine Ecosystem Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China Donghai Laboratory Zhoushan 316021China East China Sea Ecological Center Ministry of Natural ResourcesShanghai 201206China Key Laboratory of Marine Ecological Monitoring and Restoration Technologies Ministry of Natural ResourcesShanghai 201206China Observation and Research Station of Yangtze River Delta Marine Ecosystems Ministry of Natural ResourcesZhoushan 316021China

The sinking of phytoplankton is critical to organic matter transportation in the ocean and it is an essential process for the formation of coastal hypoxic *** study was based on a field investigation conducted during the summer of 2022 in the Changjiang River(Yangtze River) Estuary(CJE) and its adjacent *** settling column method was employed to measure the sinking velocity(SV) of different size fractions of phytoplankton at the surface of the sea and to analyze their environmental control *** findings reveal significant spatial variation in phytoplankton SV(-0.55-2.41 m/d) within the ***-speed sinking was predominantly observed in phosphate-depleted regions beyond the CJE *** the same time,an upward trend was more commonly observed in the phosphate-rich regions near the CJE *** SV ranges for different sizefractionated phytoplankton,including micro-(>20 μm),nano-(2-20 μm),and picophytoplankton(0.7-2 μm),were-0.50-4.74 m/d,-1.04-1.59 m/d,and-1.24-1.65 m/d,*** analysis revealed a significant negative correlation between SV and dissolved inorganic phosphorus(DIP),implying that the influence of DIP contributes to *** variations in phytoplankton alkaline phosphatase activity suggested a significant increase in SV across all size fractions in the event of phosphorus *** communities with limited photo synthetic capacity(maximum photochemical efficience,Fv/Fm <0.3) were found to have higher SV than that of communities with strong capacity,suggesting a link between sinking and alterations in physiological conditions due to phosphate *** findings from the in situ phosphate enrichment experiments confirmed a marked decrease in SV following phosphate *** findings suggest that phosphorus limitation is the primary driver of elevated SV in the *** study enhances the comprehension of the potential mechanisms underlying hypoxic zone formation in the CJE,providing no

关键词： phytoplankton sinking velocity Changjiang River Estuary phosphorus limitation alkaline phosphatase

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

Fast X-ray imaging beamline at SSRF

引用

Nuclear Science and Techniques 2024年第9期35卷 68-81页

作者： Ke Li Hong-Lan Xie Ya-Nan Fu Fei-Xiang Wang Guo-hao Du jian-feng ji Biao Deng Ti-Qiao Xiao Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China

The fast X-ray imaging beamline(BL16U2)at Shanghai Synchrotron Radiation Facility(SSRF)is a new beamline that provides X-ray micro-imaging capabilities across a wide range of time scales,spanning from 100 ps toμs and *** beamline has been specifically designed to facilitate the investigation of a wide range of rapid phenomena,such as the deformation and failure of materials subjected to intense dynamic *** addition,it enables the study of high-pressure and high-speed fuel spray processes in automotive *** light source of this beamline is a cryogenic permanent magnet undulator(CPMU)that is cooled by liquid *** CPMU can generate X-ray photons within an energy range of 8.7-30 *** beamline offers two modes of operation:monochromatic beam mode with a liquid nitrogen-cooled double-crystal monochromator(DCM)and pink beam mode with the first crystal of the DCM out of the beam *** X-ray imaging methods were implemented in BL16U2:single-pulse ultrafast X-ray imaging,microsecond-resolved X-ray dynamic imaging,millisecond-resolved X-ray dynamic micro-CT,and high-resolution quantitative ***,BL16U2 is equipped with various in situ impact loading systems,such as a split Hopkinson bar system,light gas gun,and fuel spray *** the completion of the final commissioning in 2021 and subsequent trial operations in 2022,the beamline has been officially available to users from 2023.

关键词： Multiple time-scale X ray imaging Single-pulse X ray imaging Dynamic 2D imaging Dynamic micro-CT

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

Activity promotion of Rh_(1)Ca_(x)/Al_(2)O_(3) single-atom catalyst in 1-octene hydroformylation:a volcano curve exists between Ca adding ratio and catalytic activity

引用

Science China Chemistry 2024年第4期67卷 1187-1192页

作者： hao Zhang Xingcong Zhang Xilun Wang Qingdi Sun hao Liu Hongbing ji Xiaohui He Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education Fine Chemical Industry Research InstituteSchool of ChemistryIGCMESun Yat-sen UniversityGuangzhou 510275China Huizhou Research Institute Sun Yat-sen UniversityHuizhou 516081China State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology Institute of Green Petroleum Processing and Light Hydrocarbon ConversionCollege of Chemical EngineeringZhejiang University of TechnologyHangzhou 310014China

Single-atom catalysts(SACs)are considered the best candidates for olefin hydroformylation due to their combined advantages of homogeneous and heterogeneous *** conventional organo-phosphine modification,Rh SAC is modified by introducing Ca,resulting in a significant increase in activity(maximum~5.7-fold)and ***,a volcano curve between Ca addition ratio and catalytic activity is *** Ca significantly increases activity by decreasing the energy barrier,but excessive Ca decreases activity due to hindering substrate adsorption and reaction.

关键词： hydroformylation bimetallic single-atom catalysts rhodium heterogeneous catalyst

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

Machine learning model based on non-convex penalized huberized-SVM

引用

Journal of Electronic Science and Technology 2024年第1期22卷 81-94页

作者： Peng Wang ji Guo Lin-feng Li School of Finance and Economics Xizang Minzu UniversityXianyang712082China Research Center for Quality Development of Xizang Special Industries Xianyang712082China School of Computer Science and Technology Xinjiang UniversityUrumqi830017China

The support vector machine(SVM)is a classical machine learning *** the hinge loss and least absolute shrinkage and selection operator(LASSO)penalty are usually used in traditional ***,the hinge loss is not differentiable,and the LASSO penalty does not have the Oracle *** this paper,the huberized loss is combined with non-convex penalties to obtain a model that has the advantages of both the computational simplicity and the Oracle property,contributing to higher accuracy than traditional *** is experimentally demonstrated that the two non-convex huberized-SVM methods,smoothly clipped absolute deviation huberized-SVM(SCAD-HSVM)and minimax concave penalty huberized-SVM(MCP-HSVM),outperform the traditional SVM method in terms of the prediction accuracy and classifier *** are also superior in terms of variable selection,especially when there is a high linear correlation between the *** they are applied to the prediction of listed companies,the variables that can affect and predict financial distress are accurately filtered *** all the indicators,the indicators per share have the greatest influence while those of solvency have the weakest *** companies can assess the financial situation with the indicators screened by our algorithm and make an early warning of their possible financial distress in advance with higher precision.

关键词： Huberized loss Machine learning Non-convex penalties Support vector machine(SVM)

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

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：