检索结果-南通市图书馆

Research on FMC analytic algorithm of PBN track transition coding

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2023年第4期34卷 1042-1052页

作者： ZHANG Guangming REN Siqian zhao weiwei LI Xiuyi School of Flight Technology Civil Aviation Flight University of ChinaGuanghan 618307China

Airborne navigation database(NavDB)coding directly affects the result of analysis on the instrument flight procedure by the modern aircraft flight management computer(FMC).A reasonable flight track transition mode can improve the track tracking accuracy and flight quality of the aircraft.According to the path terminator(PT)and track transition characteristics of the performance based navigation(PBN)instrument flight procedure and by use of the world geodetic system(WGS)-84 ellipsoidal coordinate system,the algorithms for“fly by”and“fly over”track transition connections are developed,together with the algorithms for coordinates of fix-to-altitude(FA)altitude termination point and heading-to-an-intercept(VI)track entry point and for track transition display of the navigation display(ND).According to the simulation carried out based on the PBN instrument approach procedure coding of a certain airport and the PBN route data at a high altitude,the algorithm results are consistent with the FMC-calculated results and the actual ND results.

关键词： flight management computer(FMC) performance based navigation(PBN) path terminator(PT) navigation database(NavDB)coding track transition

Effect of slope position on leaf and fine root C,N and P stoichiometry and rhizosphere soil properties in Tectona grandis plantations

在线全文

学校读者我要写书评

暂无评论

林业研究:英文版 2023年第6期34卷 1997-2009页

作者： Qingqing Zhang Zaizhi Zhou Weiwei Zhao Guihua Huang Gaofeng Liu Xiaofei Li Junduo Wu Research Institute of Tropical Forestry Chinese Academy of ForestryGuangzhou 510520People’s Republic of China Experimental Center of Tropical Forestry Chinese Academy of ForestryPingxiang 532600People’s Republic of China

Little is known about C-N-P stoichiometries and content in teak(Tectona grandis)plantations in South China,which are mostly sited on hilly areas with lateritic soil,and the effect of slope position on the accumulation of these elements in trees and rhizosphere soils.Here we analyzed the C,N,P content and stoichiometry in leaves,fine roots and rhizosphere soils of trees on the upper and lower slopes of a 12-year-old teak plantation.The Kraft classification system of tree status was used to sample dominant,subdominant and mean trees at each slope position.The results showed that the C,N and P contents in leaves were higher than in fine roots and rhizosphere soils.The lowest C/N,C/P and N/P ratios were found in rhizosphere soils,and the C/N and C/P ratios in fine roots were higher than in leaves.Nutrient accumulation in leaves,fine roots and rhizosphere soils were significantly influenced by slope position and tree class with their interaction mainly showing a greater effect on rhizosphere soils.Leaf C content and C/N ratio,fine root C and P contents,and C/N and C/P ratios all increased distinctly with declining slope position.The contents of organic matter(SOM),ammonium(NH4+-N),nitrate-nitrogen(NO3--N)and available potassium(AK)in rhizosphere soils were mainly enriched on upper slopes,but exchange calcium(ECa),available phosphorus(AP),and pH were relatively lower.Variations in the C,N and P stoichiometries in trees were mainly attributed to the differences in rhizosphere soil properties.N and P contents showed significant positive linear relationships between leaf and rhizosphere soil,and C content negative linear correlation among leaves,fine roots and rhizosphere soils.Chemical properties of rhizosphere soils,particularly C/N and NH4+-N,had significant effects on the leaf nutrients in trees on the upper slope.Correspondingly,rhizosphere soil properties mainly influenced fine root nutrients on the lower slope,and soil AK was the major influencing factor.Overall,these results offer new insights for the sustainabili

关键词： Tectona grandis Stoichiometric ratio Rhizosphere soil Dominant trees Nutrient accumulation

Energy-absorbing porous materials:Bioinspired architecture and fabrication

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第2期17卷 679-690页

作者： Junheng zhao Meng Li Jiewei Chen weiwei Gao Hao Bai State Key Laboratory of Chemical Engineering College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310058China Department of Polymer Science and Engineering Zhejiang UniversityHangzhou 310058China

Energy-absorbing materials are widely used in transportations,sports,and the military applications.Particularly,porous materials,including natural and artificial materials,have attracted tremendous attentions due to their light weight and excellent energy absorption capability.This review summarizes the recent progresses in the natural and artificial energy-absorbing porous materials.First,we review the typical natural porous materials including cuttlebone,bighorn sheep horn,pomelo peel,and sunflower stem pith.The architectures,energy absorption abilities,and mechanisms of these typical natural materials and their bioinspired materials are summarized.Then,we provide a review on the fabrication methods of artificial energy-absorbing porous materials,such as conventional foaming and three-dimensional(3D)printing.Finally,we address the challenges and prospects for the future development of energy-absorbing porous materials.More importantly,our review provides a direct guidance for the design and fabrication of energy-absorbing porous materials required for various engineering applications.

关键词： energy-absorbing porous materials natural materials natural structures bioinspired materials

Revisiting lithium-storage mechanisms of molybdenum disulfide

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

Chinese Chemical Letters 2022年第4期33卷 1779-1797页

作者： Chun Sun Mingming Liu Longlu Wang Lingbin Xie Weiwei Zhao Jianmin Li Shujuan Liu Dafeng Yan Qiang zhao College of Electronic and Optical Engineering&College of Microelectronics Institute of Flexible Electronics(Future Technology)Nanjing University of Posts&Telecommunications(NUPT)Nanjing 210023China Key Laboratory for Organic Electronics and Information Displays&Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials(IAM)Nanjing University of Posts&TelecommunicationsNanjing 210023China College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China

Molybdenum disulfide(MoS_(2)),a typical two-dimensional transition metallic layered material,attracts tremendous attentions in the electrochemical energy storage due to its excellent physicochemical properties.However,with the deepening of the research and exploration of the lithium storage mechanism of these advanced MoS_(2)-based anode materials,the complex reaction process influenced by internal and external factors hinders the exhaustive understanding of the lithium storage process.To design stable anode material with high performance,it is urgent to review the mechanisms of reported anode materials and summarize the related factors that influence the reaction processes.This review aims to dissect all possible side reactions during charging and discharging process,uncover internal and external factors inducing various anode reactions and finally put forward strategies of controlling high cycling capacity and super-stable lithium storage capability of MoS_(2).This review will be helpful to the design of MoS_(2)-based lithium-ion batteries(LIBs) with excellent cycle performance to enlarge the application fields of these advanced electrochemical energy storage devices.

关键词： Lithium-ion batteries Molybdenum disulfide(MoS_(2)) Lithium storage mechanisms MoS2-based anode materials In situ characterization methods

Cavitation of a Submerged Jet at the Spherical Valve Plate/Cylinder Block Interface for Axial Piston Pump

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2020年第5期33卷 197-211页

作者： Bin zhao weiwei Guo Long Quan College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024China Transducers and Intelligent Control System of Ministry of Education and Shanxi Province Taiyuan University of TechnologyTaiyuan 030024China The State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou 310027China

The spherical valve plate/cylinder block pair has the advantages of strong overturning resistance and large bearing area.However,the configurations of the unloading and pre-boosting triangular grooves on the spherical valve plate are different from those in the planar valve plate,resulting in special cavitation phenomenon on the spherical port plate pair.In order to study cavitation characteristics of spherical port plate pair,a dynamic CFD model of the piston pump including turbulence model,cavitation model and fluid compressibility is established.A detailed UDF compilation scheme is provided for modelling of the micron-sized spherical oil film mesh,which makes up for the lack of research on the meshing of the spherical oil film.In this paper,using CFD simulation tools,from the perspectives of pressure field,velocity field and gas volume fraction change,a detailed analysis of the transient evolution of the submerged cavitation jet in a axial piston pump with spherical valve plate is carried out.The study indicates the movement direction of the cavitation cloud cluster through the cloud image and the velocity vector direction of the observation point.The sharp decrease of velocity and gas volume fraction indicates the collapse phenomenon of bubbles on the part wall surface.These discoveries verify the special erosion effect in case of the spherical valve plate/cylinder block pair.The submerged cavitation jet generated by the unloading triangular grooves distributed on the spherical valve plate not only cause denudation of the inner wall surface of the valve plate,but also cause strong impact and denudation on the lower surface of the cylinder body.Finally,the direction of the unloading triangular groove was modified to extend the distance between it and the wall surface which can effectively alleviate the erosion effect.

关键词： Cavitation submerged jet Spherical valve plate/cylinder block pair Axial piston pump

Amorphous molybdenum sulfide and its Mo-S motifs:Structural characteristics,synthetic strategies,and comprehensive applications

在线全文

学校读者我要写书评

暂无评论

Nano Research 2022年第9期15卷 8613-8635页

作者： Cheng Chang Longlu Wang Lingbin Xie Weiwei Zhao Shujuan Liu Zechao Zhuang Shijie Liu Jianmin Li Xia Liu Qiang zhao College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology) Nanjing University of Posts&Telecommunications(NJUPT)Nanjing 210023China Key Laboratory for Organic Electronics and Information Displays&Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials(LAM)&Institute of Flexible Electronics(Future Technology)Nanjing University of Posts&TelecommunicationsNanjing 210023China College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071China Department of Chemistry Tsinghua UniversityBeijing 100084China

Amorphous materials are one kind of nonequilibrium materials and have become one of the most active research fields.Compared with crystalline solids,the theory of amorphous materials is still in infancy because their characteristic of atomic arrangement is more like liquid and has no long-range periodicity.Recently,as the representative of amorphous materials,amorphous molybdenum sulfide(a-MoS_(x))with unique physical and chemical properties has been studied extensively.However,considerable debate surrounds the structure–property relationships of a-MoS_(x)owing to its diverse Mo-S motifs.Herein,we summarize recent discoveries and research results regarding a-MoS_(x),whose structural characteristics,synthetic strategies,formation criteria,and comprehensive applications are discussed in detail.Finally,this review is ended with our personal insights and critical outlooks over the development of a-MoS_(x).

关键词： amorphous molybdenum sulfide Mo-S motifs structural characterization synthetic strategies comprehensive applications

Dislocation-strained MoS_(2)nanosheets for high-efficiency hydrogen evolution reaction

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

Nano Research 2022年第6期15卷 4996-5003页

作者： Shihao Wang Longlu Wang Lingbin Xie Weiwei Zhao Xia Liu Zechao Zhuang YanLing Zhuang Jing Chen Shujuan Liu Qiang zhao College of Electronic and Optical Engineering Nanjing University of Posts and TelecommunicationsNanjing 210023China Key Laboratory for Organic Electronics and Information Displays and Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials(IAM)and Institute of Flexible Electronics(Future Technology)Nanjing University of Posts and TelecommunicationsNanjing 210023China College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071China Department of Chemistry Tsinghua UniversityBeijing 100084China

Defect engineering is one of the effective strategies to optimize the physical and chemical properties of molybdenum disulfide(MoS_(2))to improve catalytic hydrogen evolution reaction(HER)performance.Dislocations,as a typical defect structure,are worthy of further investigation due to the versatility and sophistication of structures and the influence of local strain effects on the catalytic performance.Herein,this study adopted a low-temperature hydrothermal synthesis strategy to introduce numerous dislocation-strained structures into the in-plane and out-of-plane of MoS_(2)nanosheets.Superior HER catalytic activity of 5.85 mmol·g^(−1)·h^(−1)under visible light was achieved based on the high-density dislocations and the corresponding strain field.This work paves a new pathway for improving the catalytic activity of MoS_(2)via a dislocation-strained synergistic modulation strategy.

关键词： molybdenum disulfide dislocation strain hydrogen evolution reaction

Ultrathin Ti_(3)C_(2) nanowires derived from multi-layered bulks for high-performance hydrogen evolution reaction

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

Chinese Chemical Letters 2022年第1期33卷 557-561页

作者： Weiwei Zhao Beibei Jin Longlu Wang Chengbo Ding Mengyue Jiang Tiantian Chen Shuaihang Bi Shujuan Liu Qiang zhao Key Laboratory for Organic Electronics and Information Displays&Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials(IAM)Nanjing University of Posts&Telecommunications(NUPT)Nanjing 210023China College of Electronic and Optical Engineering&College of Microelectronics Institute of Flexible Electronics(Future Technology)Nanjing University of Posts&Telecommunications(NUPT)Nanjing 210023 China

One-dimensional ultrathin nanowires(NWs)offer a great deal of promising properties for electrochemical energy storage and conversion due to their nanoscale confinement effect and high surface-to-volume ratios.It is highly desirable to precisely design and synthesize ultrathin Ti_(3)C_(2)NWs in the aspect of size,crystalline structure and composition.Here,we report a simple alkalization strategy to design the ultrathin Ti_(3)C_(2)NWs for hydrogen evolution reaction(HER)by modulating the surface-active sites.The design principle can well improve the amount of the defect sites and ion accessibility to increase the interactions between Ti_(3)C_(2)NWs and H^(*).The optimized Ti_(3)C_(2)NWs achieve an overpotential of 476 mV at the current density of 10 mA/cm^(2)and a Tafel slope of 129 mV/dec for HER catalysis,which are superior to that of Ti_(3)C_(2)nanosheets and m-Ti_(3)C_(2).It paves an avenue for the rational transformation of MXene bulks to one-dimensional NWs catalysts for HER.

关键词： MXene Ti_(3)C_(2)nanowires Ultrathin films Chemical transformation Hydrogen evolution reaction

Geodynamic processes of the southeastern Neo-Tethys Ocean and the formation mechanism of the curved subduction system in Southeast Asia

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2023年第4期66卷 703-717页

作者： weiwei DING Rixiang ZHU Bo WAN Liang zhao Xiongwei NIU Pan zhao Baolu SUN Yanghui zhao Key Laboratory of Submarine Geoscience&Second Institute of Oceanography Ministry of Natural ResrouceHangzhou 310012China State Key Laboratory of Lithosphere Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

Southeast Asia is located at the intersection of the Tethys and Pacific domains. The superimposed effects of the two tectonic domains have resulted in complicated deep structure, surface magma responses, and dynamic processes of Southeast Asia. Based on the latest long-term passive seismic experiment and numerical modeling, this study reconstructs the dynamic processes of the closure of the Neo-Tethys Ocean and the formation of the curved subduction system in Southeast Asia since the Late Mesozoic. P-wave velocity structure shows a remnant of the Neo-Tethys subducted slab in the lower mantle beneath Southeast Asia at a depth of approximately 1500 km. On the Java-East Timor subduction zone, the remnant slab is coupled with the Indo-Australian subducting slab in the upper mantle with the same direction, while on the Sumatra subduction zone, the remnant slab is decoupled from the Indo-Australian subducting slab in different directions. The formation of the curved subduction system in Southeast Asia is resulted from the northward subdcutions of previous Neo-Tethys and current IndoAustralian Plate, and the westward subduction of the Pacific Plate since Mesozoic. The former is characterized by continuous subduction and subsequent continental block collision, forming the current continental lithosphere in Southeast Asia and the curve-shaped Sumatra-Java subduction zone;the latter is characterized by subduction retreat and back-arc spreading, forming the eastern Philippine subduction zone and a series of marginal sea basins. Since the Early Cretaceous, the opening of the North Australian Sea resulted in stagnation of the Australian Block in the high latitude area of the southern hemisphere for a long time.The North Australian Sea was dominated by out-dipping double subduction from 45 Ma, which resulted in rapid northward drifting of the Australian Block and final collision with the Sundaland.

关键词： Southeastern Neo-Tethys Ocean Curved subduction system in Southeast Asia North Australian Sea Deep structure Numerical modeling