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Acta mechanica Solida Sinica 2017年第1期30卷 11-19页

作者： Q.F.Lü m.L.Deng W.Q.zhu Department of mechanics State Key Laboratory of Fluid Power and Mechatronic SystemsKey Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceZhejiang University

A stochastic averaging method of quasi integrable and resonant Hamiltonian systems under excitation of fractional gaussian noise （fgn） with the Hurst index 1/2 〈 H 〈 1 is proposed. First, the definition and the basic property of fgn and related fractional Brownian motion （iBm） are briefly introduced. Then, the averaged fractional stochastic differential equations （SDEs） for the first integrals and combinations of angle variables of the associated Hamiltonian systems are derived. The stationary probability density and statistics of the original systems are then obtained approximately by simulating the averaged SDEs numerically. An example is worked out to illustrate the proposed stochastic averaging method. It is shown that the results obtained by using the proposed stochastic averaging method and those from digital simulation of original system agree well.

关键词： Quasi integrable and resonant Hamiltonian system Fractional Brownian motion Fractional gaussian noise Stochastic averaging method Internal resonant

COmPARISON ON REFINEmENT OF IRON POWDER BY BALL mILLINg ASSISTED BY DIFFERENT EXTERNAL FIELDS

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Acta metallurgica Sinica(English Letters) 2006年第6期19卷 411-417页

作者： L.Y.Dai B.Cao m.zhu School of mechanical Engineering South China University of TechnologyGuangzhou 510640China marine Engineering Institute Jimei UniversityXiamen 361021China

The cryogenic milling and milling in conjunction with dielectric barrier discharge plasma (DBDP) have been separately set up. The combined effect of low temperature and plasma on ball milling has been investigated by examining the refinement of particle size and grain size of iron powder using scanning electron microscopy, X-ray diffraction, and small angle X-ray scattering. It was found that the mean size of iron particles could reach 104nm only after 10 hours of ball milling in conjunction with DBDP, whereas a minimum average grain size of 8.4nm was obtained by cryomilling at -20℃; however, it is difficult to refine the particle size and grain size under the same milling condition in the absence of DBDP and cryogenic temperature.

关键词： ball milling cryomilling dielectric barrier discharge (DBD) nanoparticle

高频超声下老年女性腓肠肌形态参数与身体活动能力的相关性分析

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中国组织工程研究 2025年第5期29卷 1058-1063页

作者：温子星徐欣朱胜群上海杉达学院国际医学技术学院上海市201209 上海师范大学天华学院健康学院上海市201815

背景:高频超声技术的应用为老年人骨骼肌形态的精准评估提供了有效工具,但获取的骨骼肌形态参数与身体活动能力之间的关联性尚不明确。目的:探究高频超声成像技术下老年女性腓肠肌形态学参数与身体活动能力的相关性,进而发现老年人身体... 详细信息

背景:高频超声技术的应用为老年人骨骼肌形态的精准评估提供了有效工具,但获取的骨骼肌形态参数与身体活动能力之间的关联性尚不明确。目的:探究高频超声成像技术下老年女性腓肠肌形态学参数与身体活动能力的相关性,进而发现老年人身体活动能力的有效预测指标。方法:于上海杉达学院周边社区招募年龄>60周岁,具有独立活动能力的老年女性受试者59例,采集受试者腓肠肌高频超声图像,获取相关参数:包括肌肉厚度、肌纤维长度、羽状角和肌纤维长度/肌肉厚度(fiber length/muscle thickness,Lf/Tm)指数;并进行身体活动能力测试:包括10 m步行、计时起立行走、30 s坐站和握力的测试,对各形态参数和身体活动能力测试指标进行相关性分析。结果与结论:①各骨骼肌形态参数间均存在显著相关性(Pm步行测试结果呈负相关(r=-0.35,Pm指数与10 m步行测试、握力测试结果呈正相关(r=0.39,Pm指数与老年女性身体活动能力表现出了较好的相关性,可作为身体活动能力预测的有效指标。

关键词：老年女性高频成像身体活动能力骨骼肌形态 10 m步行 Lf/Tm指数

Hierarchical structure and deformation behavior of a novel multicomponent β titanium alloy with ultrahigh strength

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Journal of materials Science & Technology 2022年第12期107卷 227-242页

作者： X.Li X.N.Wang K.Liu g.H.Cao m.B.Li Z.S.zhu S.J.Wu School of materials Science and Engineering Beihang UniversityBeijing 100191China Titanium Alloys Laboratory Beijing Institute of Aeronautical MaterialBeijing 100095China School of materials Science and Engineering Shanghai UniversityShanghai 200444China

Based on the general [mo] equivalent criterion and d-electron orbital theory, a new ultrahigh-strength βtitanium alloy with eight major elements(Ti-4.5Al-6.5mo-2Cr-2.6Nb-2Zr-2Sn-1V, TB17) for industrial applications was developed. An ingot of five tons was successfully melted by thrice vacuum consumable arc melting. The microstructure and elements partitioning of different conditions were investigated systematically. The results suggest that the hierarchical structures of micro-scale first α phase(αf), nano-scale secondary α phase(αs), and ultrafine FCC substructures can be tailored by solution plus aging(STA) heat treatment. The lateral and epitaxial growth of αfphase promotes the HCP-α to FCC substructure transformation with the help of elements partitioning during the aging process. moreover, the element V, generally regarded as β stabilizer, is found to mainly concentrate in the Al-rich αfphase in this study probably due to its relatively lower content and the strong bonding energy of Al-V. The hierarchical structure has a strong interaction with dislocations, which contributes to achieve a superhigh strength of 1376 *** addition, the plastic strain is partitioned in the multi-scale precipitates(such as the α and FCC substructures) and β matrix, resulting in a considerable plasticity. TEm observation demonstrates that high density entangled dislocations at interfaces and mechanical twins exist in the STA sample after tensile test. It can be deduced that both dislocation slipping and twinning mechanisms are present in this ***, TB17 alloy can serve as an excellent candidate for structural materials on aircrafts that require high strength and lightweight.

关键词： Titanium alloy Hierarchical structure Deformation behavior Ultrahigh strength Elements partitioning

The mechanical and water absorption properties of carbon fiber buoyancy materials under hydrostatic pressure

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Science China Technological Sciences 2025年第1期 251-265页

作者： Fanglin CONg Zihan LI guocai YU Yang JIN Zixu zhu Linzhi WU College of Aerospace and Civil Engineering Harbin Engineering University Key Laboratory of Advanced Ship materials and mechanics Harbin Engineering University Department of Basic Courses Naval University of Engineering

Buoyancy material technology is of paramount importance for the development of marine engineering. In this study,a novel carbon fiber buoyancy material(CFBm) is designed and prepared by utilizing composite circular tubes with light weight and high strength. To reveal the failure mechanism under hydrostatic pressure, a finite element model(FEm) based on the three-dimensional Hashin and Yeh failure criterion is developed and validated experimentally. Both the simulated and experimental results indicate that the hydrostatic strength of the CFBm is mainly determined by the buckling of carbon fiber tubes located at the edges of the CFBm. Parametric analysis is conducted to investigate the effect of the number of unit-cells,length, and wall thickness of carbon fiber tubes on the mechanical properties of the CFBm. In addition, a 60-day water absorption test of the CFBm at 12.5 mPa is conducted to characterize its durability. Experimental results indicate that the maximum water absorption rate of the CFBm is 0.59% and the hydrostatic strength is reduced by only 7.97% during the 60-day test period. Finally, the designed CFBm is used at the water depth of 1000 m as buoyancy material. Compared with traditional buoyancy materials, the proposed CFBm has significant advantages in both hydrostatic strength and density. This work has broad engineering application prospects and is of high significance for promoting the implementation of carbon fiber composites in the ocean engineering field.

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A Preliminary Comparative Study on the Centering Algorithms for CassiniISS NAC Images

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Research in Astronomy and Astrophysics 2024年第10期24卷 58-65页

作者： T.Liang Q.-F.Zhang g.-m.Liu W.-H.zhu C.-S.Wang Department of Computer Science Jinan UniversityGuangzhou 510632China Sino-French Joint Laboratory for Astrometry Dynamics and Space ScienceJinan UniversityGuangzhou 510632China School of Computer Science Guangdong University of EducationGuangzhou 510303China

Obtaining high precision is an important consideration for astrometric studies using images from the Narrow Angle Camera(NAC)of the Cassini Imaging Science Subsystem(ISS).Selecting the best centering algorithm is key to enhancing astrometric *** this study,we compared the accuracy of five centering algorithms:gaussian fitting,the modified moments method,and three point-spread function(PSF)fitting methods(effective PSF(ePSF),PSFEx,and extended PSF(x PSF)from the Cassini Imaging Central Laboratory for Operations(CICLOPS)).We assessed these algorithms using 70 ISS NAC star field images taken with CL1 and CL2 filters across different stellar *** ePSF method consistently demonstrated the highest accuracy,achieving precision below 0.03 pixels for stars of magnitude *** to the previously considered best,the modified moments method,the e PSF method improved overall accuracy by about 10%and 21%in the sample and line directions,***,the xPSF model provided by CICLOPS had lower precision than the ***,the ePSF exhibits an improvement in measurement precision of 23%and 17%in the sample and line directions,respectively,over the *** discrepancy might be attributed to the xPSF focusing on photometry rather than *** findings highlight the necessity of constructing PSF models specifically tailored for astrometric purposes in NAC images and provide guidance for enhancing astrometric measurements using these ISS NAC images.

关键词： methods:analytical techniques:image processing stars:imaging astrometry

Effective mass and Fermi surface complexity factor from ab initio band structure calculations

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npj Computational materials 2017年第1期3卷 417-423页

作者： Zachary m.gibbs Francesco Ricci guodong Li Hong zhu Kristin Persson gerbrand Ceder geoffroy Hautier Anubhav Jain g.Jeffrey Snyder California Institute of Technology Division of Chemistry and Chemical EngineeringPasadenaCAUSA Institute of Condensed matter and Nanosciences(ImCN) Universitécatholique de LouvainChemin desétoiles 8bte L7.03.01Louvain-la-NeuveBelgium Department of materials Science and Engineering Northwestern University2220 Campus DriveEvanstonILUSA Department of materials Science and Engineering Massachusetts Institute of Technology77 Massachusetts AvenueMassachusettsMAUSA Lawrence Berkeley National Lab 1 Cyclotron RoadBerkeleyCAUSA

The effective mass is a convenient descriptor of the electronic band structure used to characterize the density of states and electron transport based on a free electron *** effective mass is an excellent first-order descriptor in real systems,the exact value can have several definitions,each of which describe a different aspect of electron *** we use Boltzmann transport calculations applied to ab initio band structures to extract a density-of-states effective mass from the Seebeck Coefficient and an inertial mass from the electrical conductivity to characterize the band structure irrespective of the exact scattering *** identify a Fermi Surface Complexity Factor:N_(v)^(*)K^(*) from the ratio of these two masses,which in simple cases depends on the number of Fermi surface pockets eN_(v)^(*) T and their anisotropy K^(*),both of which are beneficial to high thermoelectric performance as exemplified by the high values found in *** Fermi Surface Complexity factor can be used in high-throughput search of promising thermoelectric materials.

关键词： mechanism materials Fermi

The recent evolution of dune landforms and its environmental indications in the mid-latitude desert area(Hexi Corridor)

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Journal of geographical Sciences 2022年第4期32卷 617-644页

作者： zhu Bingqi Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China

The history of dune landform changes and dust activity at mid-latitudes is a good archive for exploring environmental changes and related landscape *** this study,the dynamic changes,material sources,dust activity history and the influencing factors of typical sand dunes in the Hexi Corridor were comprehensively analyzed from the aspects of aeolian geomorphology,grain-size sedimentology,geochemistry and *** results show that in the past half century,the typical crescent-shaped dunes and chains of crescent-shaped dunes in the study area have moved or swayed greatly,with an average speed ranging from 0.8 m/a(Dunhuang)to 6.2 m/a(minqin).The dynamic changes of sand dunes are mainly affected by annual precipitation,annual average wind speed and annual gale days,which indicates that climate is the primary influencing factor of dune landform *** three-stage grain-size curve model of dune sands is obviously different from that of gobi sediments(two-stage),revealing the“immaturity”of the latter in sedimentology,while the former has experienced efficiently aeolian differentiation and non-local *** comprehensive evidences of paleogeography,sedimentology and geochemistry reveal that the source materials of sand dunes are mainly alluvial/proluvial and palaeo-fluvial sediments,including clastic sediments in the denudation/erosion zones of the north and south *** such as the proportion of surface fine particles,the coverage of surface salt crusts,and the content of erodible sandy materials indicate that the western gobi areas are not the main source areas of wind-blown dust in the central and eastern parts of the Hexi *** spatial distribution of the movement direction of sand dunes is similar to that of the regional dominant wind direction,which indicates that the difference in the dynamic evolution of dune landforms between the east and west of the Hexi Corridor should be controlled by the regional-scale wind system,tha

关键词： dune landform gobi landform grain size sedimentology elemental geochemistry global warming desertification mid-latitude deserts

Planetary Homeostasis of Reactive Nitrogen Through Anaerobic Ammonium Oxidation

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Engineering 2024年第7期38卷 175-183页

作者： guibing zhu Bangrui Lan Shuci Liu Cameron m.Callbeck Shanyun Wang Liping Jiang Asheesh Kumar Yadav Jan Vymazal mike S.m.Jetten ganlin Zhang Yongguan zhu Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China Department of Environment and Science Queensland GovernmentBrisbaneQLD 4102Australia Department of Environmental Sciences University of BaselBasel 4056Switzerland CSIR-Institute of minerals and materials Technology Bhubaneswar 751013India Faculty of Environmental Sciences Czech University of Life Sciences PraguePraha 16521Czech Republic Department of microbiology Radboud UniversityNijmegen 6525 XZThe Netherlands Key Laboratory of Watershed geographic Sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100049China

The availability of nitrogen(N)is crucial for both the productivity of terrestrial and aquatic ecosystems ***,the overuse of artificial fertilizers and the energy required to fix nitrogen have pushed the global nitrogen cycle(N-cycle)past its safe operating limits,leading to severe nitrogen pollution and the production of significant amounts of greenhouse gas nitrous oxide(N2O).The anaerobic ammonium oxidation(anammox)mechanism can counteract the release of ammonium and N2O in many oxygenlimited situations,assisting in the restoration of the homeostasis of the Earth’s N *** this work,we looked into the characteristics of the anammox hotspots’distribution across various types of ecosystems *** hotspots are present at diverse oxic-anoxic interfaces in terrestrial systems,and they are most prevalent at the oxic-anoxic transition zone in aquatic *** on the discovery of an anammox hotspot capable of oxidizing ammonium anoxically into N2 without N2O by-product,we then designed an innovative concept and technical routes of nature-based anammox hotspot geoengineering for climate change,biodiversity loss,and efficient utilization of water *** 15 years of actual use,anammox hotspot geoengineering has proven to be effective in ensuring clean drinking water,regulating the climate,fostering plant and animal diversity,and enhancing longterm environmental *** sustainable biogeoengineering of anammox could be a workable natural remedy to resolve the conflicts between environmental pollution and food security connected to N management.

关键词： Biogeochemical N-cycle Oxic-anoxic interface Nature-based solution Biogeoengineering Nitrogen sustainable development

Photoluminescent Properties of ZnO Films Deposited on Si Substrates

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Chinese Physics Letters 2001年第3期18卷 441-442页

作者： ZHANg guo-Bin SHI Chao-Shu HAN Zheng-Fu SHI Jun-Yan FU zhu-Xi m.Kirm g.Zimmerer National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230026 Department of Physics University of Science and Technology of ChinaHefei 230026 ⅡInstitut für Experimental Physik der Universität Hamburg Germany

The photoluminescence of ZnO films deposited on Si substrates by reactive dc sputtering has been studied by using a synchrotron radiation(SR)light *** excitation spectra show a strong excitation band around 195 nm related to 390 nm emission *** SR vacuum ultraviolet excitation,a new emission band peaked at 290 nm was found for the first time,besides the ultraviolet emission band(390 nm)and green band(520 nm).

关键词： excitation ultraviolet vacuum