检索结果-南通市图书馆

Vibrational characteristics of rotating soft cylinders

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2021年第5期64卷 34-42页

作者： Kecheng Li Yinnan Zhang Haifei Zhan yangkun du Chaofeng Li College of Ciwil Engineering and Architecture Zhejiang UniversiyHangzhou 310058China School of Mathematics and Staristics University of GlasgowGlasgow G128QQUK Key Lab of Soft Machines and Smart Devices of Zhejiang Province Zhejiang UniversiyHangzhou 310027China Soft Matter Research Center Zhejiang University Hangzhou 310027China

Rotating structural components are omnipresent in engineering structures and natural world. This work investigates the effects of the centrifugal and Coriolis forces on the free vibrational characteristics of soft cylinders rotating with respect to the axis of symmetry based on the nonlinear elasticity and linear incremental theories. The formulations indicate that the biasing deformation, instantaneous elastic moduli, and incremental equations of motion strongly depend on the rotating speed. The characteristic equation for the natural frequency is derived using the state-space method and approximate laminate *** numerical examples included in this work demonstrate that the centrifugal and Coriolis forces might have significant effects on the vibrational characteristics of the cylinder. Results of this work will benefit the design and control of novel engineering systems with rotating soft cylinders or shafts.

关键词： rotating soft cylinders vibrational characteristics centrifugal force Coriolis force

Analytical solutions for equivalent elastic compliance of cubic lattice structures subjected to hypergravity conditions

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2024年第6期40卷 11-19页

作者： Lei Wang yangkun du Guannan Wang Chaofeng Lü College of Civil Engineering and Architecture Zhejiang UniversityHangzhou310058China School of Mathematics and Statistics University of GlasgowGlasgowG128QQUK Faculty of Mechanical Engineering and Mechanics Ningbo UniversityNingbo315211China Key Lab of Soft Machines and Smart Devices of Zhejiang Province Zhejiang UniversityHangzhou310027China Soft Matter Research Center Zhejiang UniversityHangzhou310027China

In order to comprehensively understand the mechanical behavior of biological entities and aerospace applications subjected to hypergravity environments,we delve into the impact of hypergravity on the equivalent compliance of cubic lattice *** on the periodic spatial distribution,we employ a unit cell methodology to deduce the homogenized stress-strain relationship for the lattice structures,subsequently obtaining the associated equivalent *** equivalent compliance can be conveniently reduced to instances without hypergravity ***,numerical simulations are executed to validate the derivations and to illustrate that hypergravity indeed affects the mechanical properties of lattice *** introduce a non-dimensional hypergravity factor,which quantifies the impact of hypergravity magnitude relative to the Young’s modulus of the base *** findings reveal that the hypergravity factor influences perpendicular compliance quadratically and parallel compliance ***,the perpendicular shear compliance remains unaffected,whereas the parallel shear compliance experiences an inverse ***,the lattice structure transforms into a gradient material oriented in the hypergravity direction,consequently generating a scale effect.

关键词： Hypergravity Cubic lattice structures Equivalent compliance Unit cell approach

Modeling on monitoring the growth and rupture assessment of saccular aneurysms

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

Theoretical & Applied Mechanics Letters 2017年第2期7卷 117-120页

作者： yangkun du Chaofeng Lu Department of Civil Engineering Zhejiang University Hangzhou 310058 China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang University Hangzhou 310027 China Soft Matter Research Center Zhejiang University Hangzhou 310027 China

The unpredictable rupture of saccular aneurysms especially of the intracerebral aneurysm is a knotty problem that always results in high mortality. Traditional diagnosis of medical images, which gives the aneurysm size and compares with a speculated critical size from clinical statistics, was demonstrated inadequate to forecasting rupture. Here, we propose a new detecting strategy that uses a dielectric elastomer （DE） capacitance sensor to monitor the growth of saccular aneurysms and deliver both the wall stress and geometric parameters, Based on the elastic growth theory together with the finite deformation analyses, the correlation between the real-time output capacitance of the DE sensor and the wall stress and/or geometry of an aneurysm is derived. Compared to clinic statistics and biomechanics simulations, the wall stress and geometric size may be used as combined indicators to assess the rupture risk of a saccular aneurysm, Numerical results show that an output relative capacitance of 30 indicates a high risk of rupture, Finally, the sensitivity and resolution of the DE sensor are proved adequately high for monitoring the growth state and evaluating the rupture risk of a saccular aneurysm.

关键词： Saccular aneurysms Rupture risk Dielectric elastomer capacitance sensor Elastic growth theory Finite deformation

Fuzzy Random Reliability Analysis of Blocky Rock-Mass in Slopes

在线全文

学校读者我要写书评

暂无评论

Journal of China University of Mining and Technology 2005年第2期15卷 129-134页

作者： yangkun ZHANGXin SchoolofWaterResourcesandHydropower WuhanUniversityWuhanHubei430072China NorthChinaInstituteofWaterConservancyandHydroelectricPower ZhengzhouHenan450008China

Slope stability assessment is a geotechnical problem characterized by many sources of uncertainty. In clas- sical reliability analysis, only the randomness of uncertainties is taken into account but the fuzziness of them is ignored. In this paper, a fuzzy probability approach and a fuzzy JC method are presented for the reliability analysis. The two methods have been applied to stability analysis of a certain slope of permanent ship lock in the Three-Gorges Project. The results obtained from these two methods are basically the same. However, compared with the fuzzy probability means, the fuzzy JC method can reflect the real situation better because it uses a fuzzy-based analysis applied to not only limit state equation but also mechanical parameters.

关键词： blocky rock mass vector analysis fuzzy-random reliability fuzzy failure probability

Incorporating sorption/desorption of organic pollutants into river water quality model

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2004年第4期16卷 559-563页

作者： LOUBao-feng ZHULi-zhong yangkun DepartmentofEnvironmentalScience ZhejiangUniversityHangzhou310028China

Preliminary research was conducted about how to incorporate sorption/desorption of organic pollutants with suspended solids and sediments into single-chemical and one-dimensional water quality model of Jinghang Canal. Sedimentation-resuspension coefficient k 3 was deduced; characteristics of organic pollutants, concentrations and components of suspended solids/sediments and hydrological and hydraulic conditions were integrated into k 3 and further into river water quality model; impact of sorption/desorption of organic pollutants with suspended solids and sediments on prediction function of the model was discussed. Results demonstrated that this impact is pronounced for organic pollutants with relatively large K oc and K ow, especially when they are also conservative and f oc of river suspended solids/sediments is high, and that incorporation of sorption/ desorption of organic pollutants into river water quality model can improve its prediction accuracy.

关键词： water quality model sorption/desorption sedimentation-resuspension coefficient

Periodic-phase-diagram similarity method for weak signal detection

在线全文

学校读者我要写书评

暂无评论

International Journal of Mechanical System Dynamics 2021年第2期1卷 248-255页

作者： Ruilan Tian yangkun Zhang Shaopu Yang Kai Yuan Qiang Xue Quanrong Ren State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuangChina Department of Engineering Mechanics Shijiazhuang Tiedao UniversityShijiazhuangChina

The periodic-phase-diagram similarity method is proposed to identify the frequency of weak harmonic *** key technology is to find a set of optimal coefficients for duffing system,which leads to the periodic motion under the influence of weak signal and strong *** the phase diagram similarity,the influences of strong noise on the similarity of periodic phase diagram are *** principle of highest similarity of periodic phase diagram with the same frequency is detected by discussing the persistence of similarity of periodic motion phase diagram under the strong noise and the periodic-phase-diagram similarity method is *** weak signals of early fault and strong noise are input into duffing system to obtain the identified *** stochastic subharmonic Melnikov method is extended to obtain the conditions of the optimal coefficients for the identified *** on the results,the constructed frequency conversion harmonic weak signals are considered to form a datum periodic *** the change of frequency in the datum periodic system,the phase diagram similarity of the two constructed systems can be *** on the periodic-phase-diagram similarity method,the frequency of weak harmonic signals can be identified by the principle of highest similarity of periodic phase diagram with the same *** results of numerical simulation and the early fault diagnosis results of actual bearings verify the feasibility of the periodic-phase-diagram similarity *** accuracy of the detection effect is 97%,and the minimum signal-to-noise ratio is−80.71 dB.

关键词： periodic system signal-to-noise ratio stochastic subharmonic Melnikov method strong noise weak signal

Selective catalytic hydrogenation of naphthalene to tetralin over a NiMo/Al2O3 catalyst

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 Journal of Chemical Engineering 2020年第10期28卷 2566-2576页

作者： Xiaoping Su Pu An Junwen Gao RuchengWang Yujuan Zhang Xi Li yangkun Zhao Yongqi Liu Xiaoxun Ma Ming Sun School of Chemical Engineering Northwest UniversityInternational Science&Technology Cooperation Base of MOST for Clean Utilization of Hydrocarbon ResourcesChemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei EnergyShaanxi Research Center of Engineering Technology for Clean Coal ConversionCollaborative Innovation Center for Development of Energy and Chemical Industry in Northern ShaanxiXi'an 710069China Shaanxi Yanchang Petroleum(Group)Co. Ltd.Xi'an 710069China

The selective catalytic hydrogenation of naphthalene to high-value tetralin was systematically investigated.A series of Al2O3 catalysts containing different active metals(Co,Mo,Ni,W)were prepared by incipient wetness *** effects of different active metals forms(oxidation,reduction,sulfuration)and reaction conditions on naphthalene hydrogenation were investigated and the catalysts were characterized by XRD,XPS,BET,NH3-TPD and ***,Ni-Mo/Al2O3 was first used in this reactive *** results show that the oxidative4%Ni O-20%MoO3/Al2O3 is the best catalyst for the preparation of *** conversion of naphthalene and the selectivity of tetralin can reach 95.62%and 99.75%respectively at 200℃,8 h and 6 *** with reduced and sulfureted 4%Ni O-20%MoO3/Al2O3 catalysts,oxidative 4%Ni O-20%MoO3/Al2O3 has a well dispersed and uniform monolayer of the active metals,larger pore volume and size,and larger total ***-MoO3/Al2O3 has a synergistic effect between NiO activity and MoO3 selectivity.

关键词： Naphthalene Tetralin Ni-Mo/Al2O3 catalysts

The new discovery of Oligocene cyprinidae fossil in Qaidam basin, Northwest China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2017年第S1期91卷 136-137页

作者： LIU Yongjie LI Yongxiang LI Hong NIU Yuanzhe LIU Fan DONG yangkun Northwest University Xi’anShaanxi 710069

1 Introduction Some Cyprinidae fossils have been reported about 420km east of the fossil site in the same period of Wulan Husentu1 layer,and have been used as an important fossil evidence for a deep understanding of the

关键词： The new discovery of Oligocene cyprinidae fossil in Qaidam basin Northwest China length

Risk Evaluation on Logistics Finance of Agricultural Products Based on Fuzzy-AHP Model

在线全文

学校读者我要写书评

暂无评论

Asian Agricultural Research 2015年第9期7卷 1-5 8,8页

作者： Yan PANG yangkun XIA School of Transportation and Logistics Central South University of Forestry and Technology

The development of logistics finance business for agricultural products is the best way to realize the common interests of logistics enterprises,small and medium-sized agricultural product enterprises and financial institutions,which will contribute to the development of China's new socialist rural economy and the construction of " two-oriented society". As the agricultural products have some special attributes,it's easy to create the risk in carrying out the logistics finance business. The paper constructs a risk evaluation indicator system for logistics finance of agricultural product,and uses the Fuzzy-AHP model to evaluate. The results show that the comprehensive risk level is normal risk,which shows that third-party logistics enterprises can carry out the logistics financial business of agricultural products,but the risks from logistics enterprises and agricultural collateral need to be prevented.

关键词： Logistics finance Agricultural products Risk evalu