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Cyclostratigraphy and paleoclimate analysis of the Lingshui Formation in Changchang Sag,Qiongdongnan Basin,China

Energy Geoscience 2024年第1期5卷 108-120页

作者： Haizhang Yang Wu Tang Enze Xu Shangfeng Zhang Yaning Wang Min Xu China National Offshore Oil Research Institute limited Beijing100028China College of Earth Sciences Yangtze River UniversityWuhanHubei430000China

The Qiongdongnan Basin,located in the sea between Hainan Island and the Xisha Islands,is a faulted Cenozoic basin on the northern continental margin of the South China *** Changchang Sag,situated in the eastern part of the central depressional zone in the deepwater area of the Qiongdongnan Basin,exhibits a near EW-striking morphology and represents an important potential target for oil/gas ***,the age of the interface of the Lingshui Formation remains controversial,which hinders a comprehensive understanding of the tectonic evolution and hydrocarbon accumulation pattern in the Changchang *** study focuses on well A,located in the depositional center of the Changchang Sag,and employs cyclostratigraphic analysis to identify cyclic signals of the Milankovitch cycles recorded in the sedimentary *** analysis of natural gamma logging data from this well reveals the presence of 405 kyr long eccentricity cycles,100 kyr short eccentricity cycles,39.3 kyr obliquity cycles,and 20.58 kyr age precession *** employing astronomical tuning,a“floating”astronomical time scale of the Lingshui Formation spanning 5.483 million years(Myr)is *** top interface of the Oligocene in the International Geological Time Scale 2020(GTS2020),with a geological age of 23.03 Ma,is used as the time anchor to establish a high-precision absolute astronomical age framework for the Lingshui *** results indicate that the bottom interface of the first member of the Lingshui Formation is dated at 23.79 Ma,the bottom interface of the second member is dated at 25.08 Ma,and the bottom interface of the third member is dated at 28.51 ***,the average sedimentation rate during this period is estimated to be 9.261 cm/***,paleoclimate and paleoenvironmental reconstructions were carried out through quantitative analysis of spore and pollen assemblages,as well as foraminifera within the Lingshui *** analyses suggest that

关键词： Milankovitch cycle Paleoclimate Qiongdongnan Basin Cyclostratigraphy Astronomical time scale

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Analysis and suppression of operational overvoltage and inrush current for high-speed trains by automatic phase-switching technique

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High Voltage 2024年第3期9卷 733-748页

作者： Ye Cao Song Xiao Zhizong Ye Guangning Wu Yujun Guo Guoqiang Gao Chuanming Sun Jiancheng Liu Zheng Chen Hao Hou Zijing Wang Puyang Liu Yuhui Zhang Jie Yu School of Electrical Engineering Southwest Jiaotong UniversityChengduChina Guangdong Power Grid limited Liability company China Southern Power GridGuangzhouChina CRRC Qingdao Sifang Co. Ltd.QingdaoChina State Grid Chongqing Electric Power company ChongqingChina

When a high-speed train approaches the insulated phase-splitting section embedded between neighbouring power supply arms,the vacuum circuit breaker(VCB)installed on trains must be disconnected to maintain the traction power supply system as a no-load condition for completing phase-switching action,as the train passes through the phase-splitting section depending on its ***,when operating VCBs,the arc is easily triggered between the mobile contacts inside,accompanied by an overvoltage ***,to explore the generating mechanism of inrush current and operational overvoltage,a model describing the‘substation-catenary-train’traction power supply system is launched based on an equivalent circuit modelling *** the analysis of the transient VCB operational process,the phase of catenary voltage is directly related to the characteristics of the VCB switching-on overvoltage,as the traction cur-rent's phase angle is relevant to the amplitude-frequency characteristics of the VCB switching-off *** current as a noteworthy element is related to the traction transformer's *** automatic phase-switching technique is utilised to suppress both operational overvoltage and inrush current,as the optimal combination of VCB switching-on and switching-off phases considering the balance between overvoltage and inrush current is achieved based on the particle swarm algorithm.

关键词： traction phase inrush

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Dynamic thermal rating assessment of oil-immersed power transformers for multiple operating conditions

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High Voltage 2024年第1期9卷 195-205页

作者： Chen Zhang Xuzhu Dong Jiangjun Ruan Yongqing Deng School of Electrical Engineering and Automation Wuhan UniversityWuhanHubeiChina

In this article,the dynamic thermal rating assessment method of oil-immersed power transformer with multiple operating conditions is proposed,considering the constraints of hot spot temperature(HST),top oil temperature,losses of life and the maximum allowable current of on-load tap changer(OLTC)or bushing,which can determine the dynamic load curves under different operating conditions and give the most sensitive constraints to limit the dynamic load *** improve the accuracy of HST estimation,the temperature estimation model is also improved and the thermal parameters are optimised using the HST measured by optical ***,several application examples are studied for transformers in different *** results show that the normal cyclic dynamic transformer rating(DTR)is mainly limited by the losses of life when the ambient temperature is high,and the average load factor can be increased to 0.82 with a maximum load capacity of *** main limiting factor of short-term DTR is the OLTC or bushing current constraint,and the average load factor can be increased to *** maximum load capacity of the transformer under both operating conditions is 23%and 50%higher than its rated load capacity,indicating that the transformer still has a large load potential available.

关键词： load thermal power

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Experimental study of the effects of a multistage pore-throat structure on the seepage characteristics of sandstones in the Beibuwan Basin:Insights into the flooding mode

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Petroleum Science 2024年第2期21卷 1044-1061页

作者： Lei Wang Xiao Lei Qiao-Liang Zhang Guang-Qing Yao Bo Sui Xiao-Jun Chen Ming-Wei Wang Zhen-Yu Zhou Pan-Rong Wang Xiao-Dong Peng Zhanjiang Branch China National Offshore Oil Corporation(CNOOC)LimitedZhanjiang524057GuangdongChina Faculty of Earth Resources China University of Geosciences(Wuhan)Wuhan430074HubeiChina School of Resources and Safety Engineering Chongqing UniversityChongqing400044China School of Engineering University of ManchesterManchester M139WJUK Hainan Branch China National Offshore Oil Corporation(CNOOC)LimitedHaikou570311HainanChina

To investigate the relationship between grain sizes, seepage capacity, and oil-displacement efficiency in the Liushagang Formation of the Beibuwan Basin, this study identifies the multistage pore-throat structure as a crucial factor through a comparison of oil displacement in microscopic pore-throat experiments. The two-phase flow evaluation method based on the Li-Horne model is utilized to effectively characterize and quantify the seepage characteristics of different reservoirs, closely relating them to the distribution of microscopic pores and throats. It is observed that conglomerate sandstones at different stages exhibit significant heterogeneity and noticeable differences in seepage capacity, highlighting the crucial role played by certain large pore throats in determining seepage capacity and oil displacement efficiency. Furthermore, it was found that the displacement effects of conglomeratic sandstones with strong heterogeneity were inferior to those of conventional homogeneous sandstone, as evidenced by multiple displacement experiments conducted on core samples with varying granularities and flooding systems. Subsequently, core-based experiments on associated gas flooding after water flooding were conducted to address the challenge of achieving satisfactory results in a single displacement mode for reservoirs with significant heterogeneity. The results indicate that the oil recovery rates for associated gas flooding after water flooding increased by 7.3%-16.4% compared with water flooding alone at a gas-oil ratio of approximately 7000 m^(3)/m^(3). Therefore, considering the advantages of gas flooding in terms of seepage capacity, oil exchange ratio, and the potential for two-phase production, gas flooding is recommended as an energy supplement mode for homogeneous reservoirs in the presence of sufficient gas source and appropriate tectonic angle. On the other hand, associated gas flooding after water flooding is suggested to achieve a more favorable develop

关键词： Beibuwan Basin Multistage pore-throat structure Multistage seepage characteristics Microscopic visualization Heterogeneity Gas/water flooding Flooding mode

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Self-fertilization in a gonochoristic fish yellow catfish

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Aquaculture and Fisheries 2024年第2期9卷 234-244页

作者： Yue Yu Ziyi Lu Min Chen Ya Liu Yang Ding Chenhao Hu Zhigang Shen College of Fisheries Key Lab of Freshwater Animal BreedingMinistry of Agriculture and Rural AffairsWuhan430070China Key Lab of Agricultural Animal Genetics Breeding and Reproduction of Ministry of EducationWuhan430070China Engineering Technology Research Center for Fish Breeding and Culture in Hubei Province Wuhan430070China Engineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt of Ministry of Education Huazhong Agricultural UniversityWuhan430070China Hubei Huangyouyuan Fishery Development limited company Wuhan430070China

Sex control techniques are in great demand for aquaculture because of the huge benefits of mono-sex *** a previous study on yellow catfish(Tachysurus fulvidraco),intersex individuals were produced by administrating 17α-methyltestosterone(MT)or aromatase inhibitor letrozole(LZ).The ovarian and testicular portions of intersexual gonads developed well and were completely separated,arousing our interest in producing self-fertilizable fish and clone-like fish *** this study,yellow catfish fry were treated with a combination of MT and LZ at a low dose(5 mg kg^(-1)MT,300 mg kg^(-1)LZ)at a low water temperature(27.0℃,mixed sex-producing temperature,LL group)and a high temperature(33.5◦C,male-producing temperature,HL group),and with a high dose(10 mg kg^(-1) MT,600 mg kg^(-1) LZ)at a low water temperature(LH group),during 12-65 days post-hatching,the critical period of sex *** XX and XY intersex were produced with different percentages at the same time through co-treatment with MT and LZ,with or without the help of male-producing *** highest percentage of XY intersex(53%in XY,36%in XX and XY)and XX intersex(47%in XX,25%in XX and XY)was produced in LH and HL groups,*** of gonadal morphology,histology,and sperm dynamic analysis indicate that some XX and XY intersex individuals were capable of self-fertilization through artificial *** reproductive performance of these intersex individuals was then investigated by injecting spawning agents,dissecting gonads,and artificially fertilizing eggs with their own *** XX,XY,and YY genotypic individuals were produced by the self-fertilization of XY intersex *** present study successfully produced high percentages of XX and XY intersex and conducted self-fertilization by mating the eggs and sperm of a single intersex ***-fertilization in fish will show great potential in aquaculture genetics and breeding,for example,generating high

关键词： Sex differentiation Self-fertilization Sex reversal Mono-sex Clone

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Evaluation on the state of sand filling layer and the influence on segment deformation of immersed tunnels

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Underground Space 2024年第3期16卷 224-238页

作者： Ziyao Xu Ailan Che Chao Su School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China CCCC Second Harbor Engineering company Ltd. Wuhan 430040China

The immersed tunnel is considered an effective solution for traffic problems across rivers and *** sand filling layer,as an important part of immersed tunnel foundation treatments,directly affects segment attitude *** to difficulties in quality control of concealed construction and the complex hydrodynamic environment,the sand filling layer is prone to compaction defects,further leading to changes in segment ***,limited by structural concealment and state complexity,most studies consider the sand filling layer part of the foundation to study its impact on settlement while neglecting its influence on segment *** research proposes an evaluation method for the sand filling layer state based on elastic wave testing and the elastic wave characteristic parameters selected come from analysis of the time domain,frequency domain and time–frequency *** classifying the elastic wave characteristic parameters through the K-means clustering method,the relationship between the state of the sand filling layer and the elastic wave characteristic parameters is *** state of the sand filling layer is divided into dense,incompact,and void.A numerical model is established based on the Guangzhou BI-UT immersed tunnel with incompact and void sand filling layer states to simulate deformation and *** results indicate that the settlement of the tunnel segment is low in the eastern region and high in the western region due to the presence of a less dense sand filling layer,with a maximum differential settlement of 0.04 *** evaluation method plays a crucial role in guiding the construction of immersed tube tunnels.

关键词： Sand filling layer state Immersed tunnel Elastic wave test Clustering algorithm

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Pavement Pothole Detection System Based on Deep Learning and Binocular Vision

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Journal of Traffic and Transportation Engineering(English Edition) 2024年

作者： Tian Guan Jianyuan Cai Yu Wang Wei Yang Xiaobo Chang Yi Han School of Automobile， Chang'an University China National Heavy Duty Truck Group company limited

Due to strong vibrations and the impact on high-speed vehicles， road potholes may cause discomfort to passengers， damaging the durability of the suspension and the integrity of the cargo. Therefore， a road pothole detection system is proposed， which uses deep learning and binocular vision for precise detection in the front. Based on the impact of road surface potholes on human driving behavior decisions of manually driven vehicles， which can cause drivers to slow down or stop， change driving routes， or even increase accident risks， road surface potholes can be divided into three categories: severe potholes (deep and large potholes)， non damaged road surfaces (flat surfaces without obvious potholes or damage)， and completely damaged road surfaces (there may be large areas of potholes， cracks， or other structural damage). 6848 road surface pit condition recognition datasets were constructed using a vehicle mounted binocular camera. Group attention shuffling block (CASB) is designed to enhance the expression of channel and spatial feature information in road images， while improving the existing shuffling network (ShuffleNetv2). This establishes a ShuffleNetv2 (CASB ShuffleNetv2) model based on mixed attention for identifying the state of road potholes. The experimental results show that the model has better accuracy than the basic model and can effectively detect road potholes. Due to the varying sizes of potholes on the road surface， small potholes may only require slight avoidance， while large potholes may cause serious vehicle damage. And there are different visual effects on the vertical distance of the pit. To address the aforementioned issues， the LabelImg image annotation tool was used to manually annotate the pothole areas， in order to construct a dataset for detecting 2029 road pothole areas. We replaced the ordinary convolution in the CenterNet feature extraction network with pyramid convolution with multiple receptive fields， and designed a feature fusion mo

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SFC placement and dynamic resource allocation based on VNF performance-resource function and service requirement in cloud-edge environment

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Journal of Systems Engineering and Electronics 2024年第4期35卷 906-921页

作者： HAN Yingchao MENG Weixiao FAN Wentao School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China China Mobile(Suzhou)Software Technology company limited Suzhou 215000China

With the continuous development of network func-tions virtualization(NFV)and software-defined networking(SDN)technologies and the explosive growth of network traffic,the requirement for computing resources in the network has risen *** to the high cost of edge computing resources,coordinating the cloud and edge computing resources to improve the utilization efficiency of edge computing resources is still a considerable *** this paper,we focus on optimiz-ing the placement of network services in cloud-edge environ-ments to maximize the *** is first proved that,in cloud-edge environments,placing one service function chain(SFC)integrally in the cloud or at the edge can improve the utilization efficiency of edge *** a virtual network function(VNF)performance-resource(P-R)function is proposed to repre-sent the relationship between the VNF instance computing per-formance and the allocated computing *** select the SFCs that are most suitable to deploy at the edge,a VNF place-ment and resource allocation model is built to configure each VNF with its particular P-R ***,a heuristic recur-sive algorithm is designed called the recursive algorithm for max edge throughput(RMET)to solve the *** simula-tions on two scenarios,it is verified that RMET can improve the utilization efficiency of edge computing resources.

关键词： cloud-edge environment virtual network function(VNF)performance-resource(P-R)function edge resource allo-cation

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General radical difluoromethylation using difluoroacetic anhydride via photoredox catalysis

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Science China Chemistry 2024年第8期67卷 2637-2646页

作者： Meng He Yankai Yang Heng Zhang Zhipeng Guan Zhi-Bing Dong Hong Yi Aiwen Lei School of Chemistry and Environmental Engineering Wuhan Institute of TechnologyWuhan 430205China College of Chemistry and Molecular Sciences and Institute for Advanced Studies(IAS) Wuhan UniversityWuhan 430072China

CF_(2)H-containing molecules play pivotal roles in diverse fields from medicinal chemistry to materials science. However, the application of existing CF_(2)H reagents as a source of CF_(2)H radical is limited by their reactivity and preparation. Herein, we develop a simple and general visible-light-catalyzed radical difluoromethylation reaction of alkenes, dienes, and heteroaromatics using commercially available, easy-to-handle, and low-cost difluoroacetic anhydride as the CF_(2)H reagent. This scalable protocol enables the convenient synthesis of a range of CF_(2)H-containing compounds under mild conditions, exhibiting a broad substrate scope and functional group tolerance. Potential applications are further demonstrated by gram-scale synthesis, sunlight experiments, derivatization experiments as well as the synthesis of bioactive molecules.

关键词： radical difluoromethylation alkenes/dienes/heteroaromatics difluoroacetic anhydride photoredox

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Programmable meta-holography dynamics enabled by grating-modulation

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Photonics Research 2024年第7期12卷 1522-1526页

作者： RUNLONG RAO SHUAI WAN ZHE LI YANGYANG SHI ZHONGYANG LI Electronic Information School Wuhan UniversityWuhan 430072China wuhan Institute of Quantum Technology Wuhan 430206China School of Microelectronics Wuhan UniversityWuhan 430072China Suzhou Institute of wuhan University Suzhou 215123China

Towards next-generation intelligent display devices, it is urgent to find a cheap and convenient dynamic optical control method. Conventional gratings are widely used as cheap diffractive elements due to their effective optical control capabilities. However, they are limited within multi-function or complex optical modulation due to the lack of accurate control of the amplitude/phase at pixel-level. Here, a metasurface-assisted grating-modulation system is originally proposed to achieve switchable multi-fold meta-holographic dynamics. By incorporating metasurfaces with traditional gratings and tuning their relative coupling positions, the modulation system gains the optical modulation capability to realize complex optical functionalities. Specifically, by varying the grating periods/positions relative to the metasurface, 2–8 holographic image channels are programmed to be dynamically exhibited and switched. The proposed metasurface-assisted grating-modulation approach enjoys cost-effective convenience, strong encoding freedom, and facile operation, which promises programmable optical displays,optical sensors, optical information encryption/storage, etc.

关键词： tuning switched holographic

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