检索结果-南通市图书馆

Towards accurate mapping of loess waterworn gully by integrating google earth imagery and DEM using deep learning

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Soil and Water Conservation Research 2024年第1期12卷 13-28页

作者： rong Chen Yi Zhou Zetao Wang Ying li Fan li Feng Yang School of Geography and Tourism Shaanxi Normal UniversityXi'an710119China National Experiment and Teaching Demonstration Center for Geography Xi'an710119China SuperMap Software Co. Ltd.Beijing100015China School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen518055China

Accurate mapping of loess waterworn gully(LWG)is essential to further study gully erosion and geomorphological evolution for the Chinese Loess Plateau(CLP).Due to the vertical joint and collapsibility of loess,LWGs have the characteristics of zigzag and unique slope abruptness under synthetic action of hydraulic force and *** forces existing LWG mapping methods to either focus on the improvement of mapping accuracy or center on the increase of mapping ***,simultaneously achieving accurate and efficient mapping of LWG is still in its infancy under complex topographic ***,we proposed a method that innovatively integrates the loess slope abruptness feature into an improved deep learning semantic segmentation framework for LWG mapping using 0.6 m Google imagery and 5 m DEM *** selected four study areas representing typical loess landforms to test the performance of our *** proposed method can achieve satisfactory mapping results,with the F1 score,mean Intersection-over-Union(mIoU),and overall accuracy of 90.5%,85.3%,and 92.3%,*** addition,the proposed model also showed significant accuracy improvement by inputting additional topographic information(especially the slope of slope).Compared with existing algorithms(Random forests,original DeepLabV3+,and Unet),the proposed approach in this study achieved a better accuracy-efficiency ***,the method can ensure high accuracy and efficiency of the LWG mapping for different loess landform types and can be extended to study various loess gully mapping and water and soil conservation.

关键词： Loess waterworn gully Topographic information Mapping Deep learning Soil erosion Loess plateau

Advancements in synthetic and electrocatalytic exploitation of guest-host intercalated 2D materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2024年第3期34卷 454-469页

作者： qian Yang Kun Wang Meiling Zhang Feihong Du Jiayang li Chen Zheng Jinyang li School of Chemistry Southwest Jiaotong University Yibin Institute of Southwest Jiaotong University

The emergence and development of layered materials have shown great promise for many applications, especially in recent years, the effective modulation of the physicochemical properties of layered materials by intercalation chemistry has led to great potential in material design. In this paper, we review the reaction mechanisms of different guest species(metal atoms/ions, organic molecules/ions, inorganic molecules and inorganic ions)intercalated into the host layered materials as well as the recent progress. It is also reviewed that layered intercalated materials with controllable structure and tunable physicochemical properties can be prepared through the occurrence of interactions between different subjects and guests. The specific applications of intercalation chemistry in the field of electrocatalysis, such as the hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction and other electrocatalytic reactions, are then discussed, with emphasis on the mechanism of the improved catalytic activity and stability of the layered materials after guest intercalation.

关键词： Electrocatalysis Guest species Intercalation chemistry Layered materials

Micro segment analysis of supercritical methane thermal-hydraulic performance and pseudo-boiling in a PCHE straight channel

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 1275-1289页

作者： qian li Zi-Jie lin liu Yang Yue Wang Yue li Wei-Hua Cai Laboratory of Thermo-Fluid Science and Nuclear Engineering Northeast Electric Power UniversityJilin132000JilinChina School of Energy and Power Engineering Northeast Electric Power UniversityJilin132000JilinChina

The printed circuit heat exchanger(PCHE) is receiving wide attention as a new kind of compact heat exchanger and is considered as a promising vaporizer in the LNG process. In this paper, a PCHE straight channel in the length of 500 mm is established, with a semicircular cross section in a diameter of 1.2 *** simulation is employed to investigate the flow and heat transfer performance of supercritical methane in the channel. The pseudo-boiling theory is adopted and the liquid-like, two-phase-like, and vapor-like regimes are divided for supercritical methane to analyze the heat transfer and flow *** results are presented in micro segment to show the local convective heat transfer coefficient and pressure drop. It shows that the convective heat transfer coefficient in segments along the channel has a significant peak feature near the pseudo-critical point and a heat transfer deterioration when the average fluid temperature in the segment is higher than the pseudo-critical point. The reason is explained with the generation of vapor-like film near the channel wall that the peak feature related to a nucleateboiling-like state and heat transfer deterioration related to a film-boiling-like state. The effects of parameters, including mass flow rate, pressure, and wall heat flux on flow and heat transfer were *** calculating of the averaged heat transfer coefficient of the whole channel, the traditional method shows significant deviation and the micro segment weighted average method is adopted. The pressure drop can mainly be affected by the mass flux and pressure and little affected by the wall heat flux. The peak of the convective heat transfer coefficient can only form at high mass flux, low wall heat flux, and near critical pressure, in which condition the nucleate-boiling-like state is easier to appear. Moreover,heat transfer deterioration will always appear, since the supercritical flow will finally develop into a filmboiling-like state. So hea

关键词： Printed circuit heat exchanger Vaporization Supercritical methane Pseudo-boiling Micro segment analysis

Spatio-Temporal Service Analysis in Multi-Layer Non-Terrestrial Networks

在线全文

学校读者我要写书评

暂无评论

Journal of Communications and Information Networks 2024年第1期9卷 43-55页

作者： qian Chen Weixiao Meng Shuai Han Cheng li School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China School of Engineering Science Simon Fraser UniversityBurnabyBC V5A 1S6Canada Department of Electrical and Computer Engineering Memorial UniversitySt.John’sNL A1B 3X5Canada

In the advent of the 6G era, non-terrestrial networks (NTN) with expansive coverage are being increasingly recognized as a vital supplement to cellular networks for facilitating seamless communication. The intricate interplay between network performance and service quality necessitates a thorough investigation into the modeling and analysis of services for efficient construction of *** studies on service analysis, predominantly focused on terrestrial networks,fall short in addressing the unique challenges posed by NTN,particularly those related to platform distribution and antenna gain modeling. This deficiency in research,coupled with the varying preferences of users for different network types, forms the basis of this study. This paper explores the spatio-temporal characteristics of services within a multi-layered NTN *** this context,the spatial distribution of the platforms is modeled using a binomial point process, and the antennas are characterized by a sectorized beam pattern. We derive the closed-form expressions for the association probability,the number of accessed users, and the arrival rate of services with certain delay requirements towards different types of NTN. Simulation results are provided to evaluate the influence of various parameters on the association probability, the number of accessed users, and the total arrival rate of services. The number of satellites can be determined to achieve the optimal system utility,balancing the accessed services, offloading effects, and launching costs. This initial investigation lays the groundwork for further theoretical progress in the service analysis and platform deployment of NTN.

关键词： association strategy non-terrestrial networks service analysis stochastic geometry system utility

Unstructured Big Data Threat Intelligence Parallel Mining Algorithm

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Big Data Mining and Analytics 2024年第2期7卷 531-546页

作者： Zhihua li Xinye Yu Tao Wei Junhao qian School of Artificial Intelligence and Computer Science Jiangnan UniversityWuxi 214122China School of IoT Engineering Jiangnan UniversityWuxi 214122China

To efficiently mine threat intelligence from the vast array of open-source cybersecurity analysis reports on the web,we have developed the Parallel Deep Forest-based Multi-Label Classification(PDFMLC)***,open-source cybersecurity analysis reports are collected and converted into a standardized text ***,five tactics category labels are annotated,creating a multi-label dataset for tactics *** the limitations of low execution efficiency and scalability in the sequential deep forest algorithm,our PDFMLC algorithm employs broadcast variables and the Lempel-Ziv-Welch(LZW)algorithm,significantly enhancing its acceleration ***,our proposed PDFMLC algorithm incorporates label mutual information from the established dataset as input *** captures latent label associations,significantly improving classification ***,we present the PDFMLC-based Threat Intelligence Mining(PDFMLC-TIM)*** results demonstrate that the PDFMLC algorithm exhibits exceptional node scalability and execution ***,the PDFMLC-TIM method proficiently conducts text classification on cybersecurity analysis reports,extracting tactics entities to construct comprehensive threat *** a result,successfully formatted STIX2.1 threat intelligence is established.

关键词： unstructured big data mining parallel deep forest multi-label classification algorithm threat intelligence

Design of new chemicals for advanced electrolytes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第5期67卷 1378-1380页

作者： Haoran Cheng Zheng Ma qian li Jun Ming State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China University of Science and Technology of China Hefei 230026China

This highlight is inspired by a recent article in Nature Energy in which liu and co-workers [1] from Tsinghua University designed a new asymmetric lithium salt (i.e., lithium 1,1,1-trifluoro-N-[2-[2-(2-methoxy ethoxy)ethoxy]ethyl] methanesulfonamide (li FEA)) and applied it as a new lithium-salt additive in the conventional carbonate-based electrolyte,overcoming the incompatibility issue of carbonate electrolytes with lithium metal in lithium metal batteries (LMBs),even achieving a fast-charging feature.

关键词： lithium carbonate electrolyte

Risk factors,prognostic factors,and nomograms for distant metastasis in patients with diagnosed duodenal cancer:A population-based study

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Oncology 2024年第4期16卷 1384-1420页

作者： Jia-rong Shang Chen-Yi Xu Xiao-Xue Zhai Zhe Xu Jun qian Department of Oncology Jiangsu Province Hospital of Chinese MedicineThe Affiliated Hospital of Nanjing University of Chinese MedicineNanjing 210000Jiangsu ProvinceChina Department of Proctology Nanjing Hospital of Chinese MedicineNanjing 210000Jiangsu ProvinceChina Department of Digestive Cancer Surgery Jiangsu Province Hospital of Chinese MedicineThe Affiliated Hospital of Nanjing University of Chinese MedicineNanjing 210000Jiangsu ProvinceChina

BACKGROUND Duodenal cancer is one of the most common subtypes of small intestinal cancer,and distant metastasis(DM)in this type of cancer still leads to poor *** nomograms have recently been used in tumor areas,no studies have focused on the diagnostic and prognostic evaluation of DM in patients with primary duodenal *** To develop and evaluate nomograms for predicting the risk of DM and person-alized prognosis in patients with duodenal *** Data on duodenal cancer patients diagnosed between 2010 and 2019 were extracted from the Surveillance,Epidemiology,and End Results *** and multivariate logistic regression analyses were used to identify independent risk factors for DM in patients with duodenal cancer,and univariate and multivariate Cox proportional hazards regression analyses were used to determine independent prognostic factors in duodenal cancer patients with *** novel nomograms were established,and the results were evaluated by receiver operating characteristic(ROC)curves,calibration curves,and decision curve analysis(DCA).RESULTS A total of 2603 patients with duodenal cancer were included,of whom 457 cases(17.56%)had DM at the time of *** analysis revealed independent risk factors for DM in duodenal cancer patients,including gender,grade,tumor size,T stage,and N stage(Plidated in the training set,validation set,and expanded testing set using ROC curves,calibration curves,and DCA *** results of Kaplan-Meier survival curves(P<0.001)indicated that both nomograms accurately predicted the occurrence and prognosis of DM in patients with duodenal *** The two nomograms are expected as effective tools fo

关键词： Duodenal cancer Distant metastasis Nomogram Risk factors Prognostic factors

An improved algorithm based on equivalent sound velocity profile method at large incident angle

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2024年第2期43卷 161-167页

作者： qianqian li qian Tong Fanlin Yang Qi li Zhihao Juan Yu Luo College of Geodesy and Geomatics Shandong University of Science and TechnologyQingdao 266590China College of Underwater Acoustic Engineering Harbin Engineering UniversityHarbin 150001China

With the development of ultra-wide coverage technology,multibeam echo-sounder(MBES)system has put forward higher requirements for localization accuracy and computational efficiency of ray tracing *** classical equivalent sound speed profile(ESSP)method replaces the measured sound velocity profile(SVP)with a simple constant gradient SVP,reducing the computational workload of beam ***,in deep-sea environment,the depth measurement error of this method rapidly increases from the central beam to the edge *** analyzing the positioning error of the ESSP method at edge beam,it is discovered that the positioning error increases monotonically with the incident angle,and the relationship between them could be expressed by polynomial ***,an error correction algorithm based on polynomial fitting is *** simulation experiment conducted on an inclined seafloor shows that the proposed algorithm exhibits comparable efficiency to the original ESSP method,while significantly improving bathymetry accuracy by nearly eight times in the edge beam.

关键词： equivalent sound speed profile ray tracing method large incident angle edge beam deep sea error correction multibeam echo-sounder system

Laser-rewritable room temperature phosphorescence based on in-situ polymerized tartaric acid

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第9期67卷 3029-3038页

作者： Tuo-Yu Zhou Tai-Wen li Hai-Fu Zhang Rui-lin Chai qian Zhao Penglin Zhang Guang-Yue li qian-Wen Wang Chang li Yu Shu Zhi Fan Sheng-Hua li College of Chemical Engineering and Materials Science College of SciencesTianjin University of Science&TechnologyTianjin 300457China College of Chemical Engineering North China University of Science and TechnologyTangshan 063210China Tianjin Key Laboratory of Multiplexed Identification for Port Hazardous Chemicals Tianjin University of Science&TechnologyTianjin 300457China

Organic room temperature phosphorescence(RTP)materials have potential applications in information technology and ***,the precise control of the afterglow in reversible manners remains challenging for organic ***,we report a kind of organic RTP material fabricated by simple heating mixtures of tartaric acid(TA)and aromatic acids,which can switch their phosphorescence by *** mixtures show tunable phosphorescence from indigo to orange with phosphorescence efficiency of up to 53.99% due to locking different organic luminogens by the TA-formed matrix through the noncovalent *** afterglow of those materials lasts a few seconds and disappears by water fumigation,which can be repeated in response to wet/heat *** drop-casting those materials on glass slides,a laser-repatternable phosphorescence is achieved by facile laser direct writing and quenched by water *** results open the opportunity for the design of smart stimuli-responsive phosphorescence materials from sustainable natural products.

关键词： room temperature phosphorescence tunable afterglows tartaric acid laser direct writing stimuli-response