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Tropical cyclone genesis over the western north Pacific in La Ni?a decay summers: Comparison between 2018 and 2021

Science China Earth Sciences 2024年第10期67卷 3098-3109页

作者： Yunyun liu Zhensong GONG China Meteorological Administration Key Laboratory for Climate Prediction Studies National Climate CentreBeijing 100081China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China

As the primary interannual signal of variability in the tropical ocean-atmosphere interaction, the El Ni?o-Southern Oscillation has a considerable impact on tropical cyclone(TC) activity over the western North Pacific(WNP). Both 2018 and2021 were La Ni?a decay years, but TC activity over the WNP during the two summers(June–August) showed notable differences. In 2018, summer TC activity was unusually high with a total of 18 TCs, and the region of TC genesis was mainly in the central and eastern WNP. In contrast, only 9 TCs were generated in summer 2021, and the region of TC genesis was primarily in the western WNP. By comparing the characteristics of the large-scale environmental conditions over the regions of TC genesis, the thermal factors of the tropical oceans, and the activity of the Madden-Julian Oscillation(MJO), this study revealed the possible causes for the marked differences in TC genesis over the WNP during the two summers, which both had a similar background of La Ni?a decay. The Indian Ocean Basin Mode(IOBM) transitioned of a cold anomaly in the winter of 2017/2018and persisted until summer 2018. At the same time, the Pacific Meridional Mode(PMM) maintained a positive phase, leading to eastward and northward displacement of the Western Pacific Subtropical High in summer, and eastward extension of the tropical monsoon trough, which presented conditions conducive to TC genesis over the Northwest Pacific. Moreover, the days when the MJO stagnated in phases 5 and 6 in the summer of 2018 increased by approximately 150% relative to climatological state,providing dynamic conditions favorable for TC formation. In 2021, the IOBM quickly turned to a warm anomaly in March and persisted until summer, whereas the PMM became a negative phase in January and remained so until summer. At the same time,the MJO stagnated in phases 2 and 3 for up to 47 days, with the center of convection located over the western Maritime Continent, producing conditions unconducive to TC ge

关键词： Tropical cyclone La Nina events Indian Ocean Basin Mode Pacific Meridional Mode Madden-Julian Oscillation Western Pacific Subtropical High Monsoon trough

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Self-Aligning Multi-Modal Transformer for Oropharyngeal Swab Point Localization

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Tsinghua Science and Technology 2024年第4期29卷 1082-1091页

作者： Tianyu liu Fuchun Sun Department of Computer Science and Technology Tsinghua UniversityBeijing 100083China

The oropharyngeal swabbing is a pre-diagnostic procedure used to test various respiratory diseases, including COVID and Influenza A (H1N1). To improve the testing efficiency of testing, a real-time, accurate, and robust sampling point localization algorithm is needed for robots. However, current solutions rely heavily on visual input, which is not reliable enough for large-scale deployment. The transformer has significantly improved the performance of image-related tasks and challenged the dominance of traditional convolutional neural networks (CNNs) in the image field. Inspired by its success, we propose a novel self-aligning multi-modal transformer (SAMMT) to dynamically attend to different parts of unaligned feature maps, preventing information loss caused by perspective disparity and simplifying overall implementation. Unlike preexisting multi-modal transformers, our attention mechanism works in image space instead of embedding space, rendering the need for the sensor registration process obsolete. To facilitate the multi-modal task, we collected and annotate an oropharynx localization/segmentation dataset by trained medical personnel. This dataset is open-sourced and can be used for future multi-modal research. Our experiments show that our model improves the performance of the localization task by 4.2% compared to the pure visual model, and reduces the pixel-wise error rate of the segmentation task by 16.7% compared to the CNN baseline.

关键词： segmentation localization transformer multi-modal perception robotic perception

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Design of efficient thermoelectric generators

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Science China Materials 2024年第1期67卷 377-378页

作者： Min liu Yanzhong Pei Interdisciplinary Materials Research Center School of Materials Science and EngineeringTongji UniversityShanghai 201804China

Thermoelectricity,which enables direct conversion between heat and electricity,undergoes impressive developments in recent decades,and is particularly promising for recovering low-grade heat of<600 K[1,2].Currently,only Bi2Te3-based thermoelectric devices are commercialized[3].However,the scarcity of tellurium(Te)(Fig.1a)is the main *** leads to numerous recent efforts on the development of efficient nonBi2Te3 thermoelectrics as potential alternatives,and successful examples(Fig.1b)include Mg3Sb2-alloys[2,3]and MgAgSb[1,2].

关键词： enable efficient electricity

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In situ probing of electron transfer at the dynamic MoS_(2)/graphene–water interface for modulating boundary slip

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Nano Research 2024年第8期17卷 7513-7521页

作者： Yishu Han Dameng liu State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

The boundary slip condition is pivotal for nanoscale fluid *** research has primarily focused on simulating the interaction mechanism between the electronic structure of two-dimensional materials and slip of water at the nanoscale,raising the possibility for ultralow friction flow of water at the ***,experimentally elucidating electronic interactions at the dynamic solid–liquid interface to control boundary slip poses a significant *** this study,the crucial role of electron structures at the dynamic solid–liquid interface in regulating slip length was ***,the slip length of water on the molybdenum disulfide/graphene(MoS_(2)/G)heterostructure(100.9±3.6 nm)significantly exceeded that of either graphene(27.7±2.2 nm)or MoS_(2)(5.7±3.1 nm)*** was also analyzed how electron transfer significantly affected interface *** electrons played a crucial role in determining the type and proportion of excitons at both MoS_(2)–water and MoS_(2)/G–water ***,by applying voltage,distinct photoluminescence(PL)responses at static and dynamic interfaces were discovered,achieving a 5-fold modulation in PL intensity and a 2-fold modulation in the trion to exciton intensity *** electrons transfer from the top graphene to the bottom MoS_(2)at the MoS_(2)/G–water interface,reducing surface charge ***,the reduction of electrostatic interactions between the solid and water leads to an increased slip length of water on the MoS_(2)/G *** process aids in comprehending the origin of frictional resistance at the subatomic *** work establishes a foundation for actively controlling and designing of fluid transport at the nanoscale.

关键词： two-dimensional materials solid-liquid interface photoluminescence excitons electron transfer slip length

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Multi-granularity sequence generation for hierarchical image classification

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Computational Visual Media 2024年第2期10卷 243-260页

作者： Xinda liu Lili Wang State Key Laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100191China Peng Cheng Laboratory Shengzhen 518000China

Hierarchical multi-granularity image classification is a challenging task that aims to tag each given image with multiple granularity labels *** methods tend to overlook that different image regions contribute differently to label prediction at different granularities,and also insufficiently consider relationships between the hierarchical multi-granularity *** introduce a sequence-to-sequence mechanism to overcome these two problems and propose a multi-granularity sequence generation(MGSG)approach for the hierarchical multi-granularity image classification ***,we introduce a transformer architecture to encode the image into visual representation ***,we traverse the taxonomic tree and organize the multi-granularity labels into sequences,and vectorize them and add positional *** proposed multi-granularity sequence generation method builds a decoder that takes visual representation sequences and semantic label embedding as inputs,and outputs the predicted multi-granularity label *** decoder models dependencies and correlations between multi-granularity labels through a masked multi-head self-attention mechanism,and relates visual information to the semantic label information through a crossmodality attention *** this way,the proposed method preserves the relationships between labels at different granularity levels and takes into account the influence of different image regions on labels with different *** on six public benchmarks qualitatively and quantitatively demonstrate the advantages of the proposed *** project is available at https://***/liuxindazz/mgs.

关键词： hierarchical multi-granularity classification vision and text transformer sequence generation fine-grained image recognition cross-modality attenti

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Comparison of Rotating Stall Warning by Different Methods for Variable Speed Configurations in a Contra-Rotating Compressor

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Journal of Thermal Science 2024年第4期33卷 1379-1393页

作者： XUE Fei WANG Yan'gang liu Qian WU Tong liu Hanru School of Power and Energy Northwestern Polytechnical UniversityXi’an710072China

Stall in compressors can cause performance degradation and even lead to *** unacceptable consequences can be avoided by timely monitoring stall inception and taking effective *** paper focused on the rotating stall warning in a low-speed axial contra-rotating ***,the stall disturbance characteristics under different speed configurations were *** results showed that as the speed ratio(RR)increased,the stall disturbance propagation speed based on the rear rotor speed gradually ***,the standard deviation(SD)method,the cross-correlation(CC)method,and the discrete wavelet transform(DWT)method were employed to obtain the stall initiation moments of three different speed *** was found that the SD and CC methods did not achieve significant stall warning results in all three speed ***,the stall initiation moment obtained by the DWT method at RR=1.125 was one period after the stall had fully developed,which was ***,a stall warning method was developed in the present work based on the long short-term memory(LSTM)regression *** applying the LSTM model,the predicted stall initiation moments of three speed configurations were at the 557th,518th,and 333rd revolution,which were44,2,and 74 revolutions ahead of stall onset moments,***,in scenarios where a minor disturbance preceded the stall,the stall warning effect of the LSTM was greatly improved in comparison with the aforementioned three *** contrast,when the pressure fluctuation before the stall was relatively small,the differences between the stall initiation moments predicted by these four methods were not significant.

关键词： contra-rotating compressor stall disturbance stall initiation moment long short-term memory(LSTM) stall warning

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Transition metal clusters with precise numbers of atoms anchored on graphdiyne as multifunctional electrocatalysts for OER/ORR/HER:a computational study

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Rare Metals 2024年第7期43卷 3107-3117页

作者： Xin-Yang liu Jing-Wei liu Gang Li Jing-Xiang Zhao College of Chemistry and Chemical Engineering Harbin Normal UniversityHarbin 150025China

Subnanometer metal clusters play an increasingly important role in heterogeneous catalysis due to their high catalytic activity and *** this work,by means of the density functional theory(DFT) calculations,the catalytic activities of transition metal clusters with precise numbers of atoms supported on graphdiyne(TM_(1-4)@GDY,TM=V,Cr,Mn,Fe,Co,Ni,Cu,Ru,Rh,Pd,Ir,Pt) were investigated for oxygen evolution reactions(OER),oxygen reduction reactions(ORR) and hydrogen evolution reactions(HER).The computed results reveal that the Pd_(2),Pd_(4) and Pt_(1) anchored graphdiyne can serve as trifunctional catalysts for OER/ORR/HER with the overpotentials of 0.49/0.37/0.06,0.45/0.33/0.12 and 0.37/0.43/0.01 V,respectively,while Pd_(1) and Pt_(2)@graphdiyne can exhibit excellent catalytic performance for water splitting(OER/HER) with the overpotentials of 0.55/0.17 and 0.43/0.03 *** addition,Ni_(1) and Pd_(3) anchored GDY can perform as bifunctional catalysts for metal-air cells(OER/ORR) and fuels cells(ORR/HER) with the overpotentials of 0.34/0.32 and 0.42/0.04 V,***,by precisely controlling the numbers of atoms in clusters,the TM_(1-4) anchored graphdiyne can serve as promising multifunctional electrocatalysts for OER/ORR/HER,which may provide an instructive strategy to design catalysts for the energy conversation and storage devices.

关键词： Density functional theory Graphdiyne Single-cluster catalysts Multifunctional electrocatalysts Overpotential

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区块链技术研究述评

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山东师范大学学报（自然科学版） 2020年第3期35卷 299-311页

作者：刘凤鸣陈玥彤山东师范大学商学院济南250358

在梳理和分析有关文献的基础上,简述了区块链的主要发展,并利用CiteSpace以及文献计量法对区块链的研究进行了分析.对区块链的定义从不同角度进行了阐述,剖析了区块链的架构组成及工作原理,并描述了区块链共识机制、智能合约、密码学机... 详细信息

在梳理和分析有关文献的基础上,简述了区块链的主要发展,并利用CiteSpace以及文献计量法对区块链的研究进行了分析.对区块链的定义从不同角度进行了阐述,剖析了区块链的架构组成及工作原理,并描述了区块链共识机制、智能合约、密码学机制等核心技术,总结了区块链的优异特性及其在各领域的应用研究.基于相关研究成果,分析了区块链存在的风险以及未来发展趋势.

关键词：区块链共识机制智能合约去中心化

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两种不同温度膀胱冲洗液对老年TUVP患者的影响

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中国医药导报 2010年第6期7卷 52-54页

作者：刘凤鸣曾伶芝湖南省桃江县人民医院湖南桃江413400

目的:比较两种不同温度冲洗液对老年经尿道前列腺汽化电切术(TUVP)患者的影响。方法:将140例老年TURP患者随机分为等温组和室温组,各70例。观察组术中采用37℃恒温5%葡萄糖注射液灌洗膀胱,而室温组术中采用室温5%葡萄糖注射液。比较两... 详细信息

目的:比较两种不同温度冲洗液对老年经尿道前列腺汽化电切术(TUVP)患者的影响。方法:将140例老年TURP患者随机分为等温组和室温组,各70例。观察组术中采用37℃恒温5%葡萄糖注射液灌洗膀胱,而室温组术中采用室温5%葡萄糖注射液。比较两组患者手术前后生命体征、血清内皮素-1(ET-1)水平的变化及术后两组不良反应发生的情况。结果:与术前比较,术毕时等温组的平均动脉压(MAP)明显降低、室温组的体温和MAP亦明显降低,有显著性差异(t=25.827、3.852、4.409,P0.05)。等温组寒战和电切综合征(TURS)的发生率明显低于室温组(χ2=30.179、5.833,P<0.01或P<0.05)。结论:采用37℃恒温5%葡萄糖注射液灌洗膀胱有助于预防老年TUVP患者术中低体温和减少术后并发症的发生。

关键词：经尿道前列腺汽化电切术冲洗液温度

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围手术期舒适护理对TURP患者的影响

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中国现代医生 2010年第5期48卷 67-68,86页

作者：曾伶芝刘凤鸣湖南省桃江县人民医院湖南桃江413400

目的探讨围手术期舒适护理对前列腺电切术(TURP)患者的影响。方法将100例TURP患者随机分为观察组和对照组,各50例。对照组接受常规治疗和护理,观察组在此基础上实施舒适护理。结果入室后观察组的心率、呼吸和平均动脉压值明显低于对照组... 详细信息

目的探讨围手术期舒适护理对前列腺电切术(TURP)患者的影响。方法将100例TURP患者随机分为观察组和对照组,各50例。对照组接受常规治疗和护理,观察组在此基础上实施舒适护理。结果入室后观察组的心率、呼吸和平均动脉压值明显低于对照组(均P<0.01);对照组入室后的心率、呼吸和平均动脉压值明显高于入室前(均P<0.01)。观察组术后并发症总发生率明显低于对照组(P<0.01)。结论围手术期舒适护理有助于维持TURP患者生命体征的稳定,减少术后并发症的发生。

关键词：前列腺电切术舒适护理生命体征并发症围手术期

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