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Communications in Theoretical Physics 2023年第8期75卷 1-13页

作者： Hongcai Ma Xue Mao Aiping Deng Department of Applied Mathematics Donghua UniversityShanghai 201620People's Republic of China

This paper aims to search for the solutions of the(2+1)-dimensional extended Boiti–Leon–Manna–Pempinelli *** solutions,breather solutions,mixed solutions with solitons,and lump-breather solutions can be obtained from the N-soliton solution formula by using the long-wave limit approach and the conjugate complex *** use both specific circumstances and general higher-order forms of the hybrid solutions as *** the help of maple software,we create density and 3D graphs to summarize the dynamic properties of these ***,it is possible to observe how the solutions'trajectory,velocity,and shape vary over time.

关键词： (2+1)-dimensional extended Boiti-Leon-Manna-Pempinelli equation long-wave limit method conjugate complex method interaction solutions dynamic characteristics

dynamics of microbial diversity during the composting of agricultural straw

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Journal of Integrative Agriculture 2021年第5期20卷 1121-1136页

作者： CHANG Hui-qing ZHU Xiao-hui WU Jie GUO Da-yong ZHANG Lian-he FENG Yao Henan University of Science and Technology Luoyang 471023P.R.China Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences/Key Laboratory of Plant Nutrition and FertilizerMinistry of Agriculture and Rural AffairsBeijing 100081P.R.China

The dynamic changes in microbial diversity during the aerobic composting of agricultural crop straw with additives were evaluated using high-throughput sequencing at four phases of composting(mesophilic,thermophilic,cooling and maturation phases).In addition,the physicochemical parameters of the composting system were determined in this *** fermentation time of the thermophilic period was prolonged with the addition of urea or urea combined with a microbial *** ratio of C/N and germination index variation indicated that the additives were favorable for composting,because the additives directly changed the physicochemical properties of the compost and had effects on the diversity and abundance of bacteria and *** abundance of operational taxonomic units(OTUs),diversity index(Shannon)and richness index(Chao1)of fungi and bacteria were found to significantly increase when urea+microbial agents were added to straw in the thermophilic *** relative abundance of the predominant bacteria and fungi at the phylum and genus levels differed during different composting *** abundance of the phyla Firmicutes and Proteobacteria declined in the order of treatments SNW>SN>S(S is straw only compost;SN is straw+5 kg t^(–1) urea compost;and SNW is straw+5 kg t^(–1) urea+1 kg t^(–1) microbial agent compost)in the thermophilic *** abundance of the genera Staphylococcus,Bacillus and Thermobifida followed the same order in the mesophilic *** accounted for more than 92%of the total fungal *** the progression of the composting process,the abundance of Ascomycota decreased *** abundance of Ascomycota followed the order of S>SN>SNW during the thermophilic *** abundance of Aspergillus accounted for 4–59%of the total abundance of fungi and increased during the first two sampling *** abundance followed the order of SNW>SN>***,principal component analysis(PCA)revealed that the community compositi

关键词： crop straws microbial diversity community composition dynamic characteristics high-throughput sequencing

Numerical Prediction of Vortex-Induced Vibrations on Top Tensioned Riser in Consideration of Internal Flow

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China Ocean Engineering 2008年第4期22卷 675-682页

作者：郭海燕李效民刘晓春 College of Engineering Ocean University of China

In consideration of the effect of the internal flowing fluid and the external marine environmental condition on the vortex-induced vibration （VIV） of top tensioned riser （Till）, the differential equation is derived based on work-energy principles and the riser near wake dynamics is modeled by Facchinetti＇ s wake oscillator model. Then Galerkin＇ s finite element approximation is implemented to derive the nonlinear matrix equation of the coupled equations and file corresponding numerical programs are compiled which solve the coupled equations directly in the time domain. The comparison of the predicted results with the recent experimental results and the prediction of SHEAR7 is performed. The results show the validity of the proposed method on the prediction of VIV of deep water risers. The effect of internal flow on the dynamic characteristics and dynmnic response of the riser is analyzed and several valuable conelusions are drawn.

关键词： top tensioned riser ( TTR) internal flow vortex-induced vibration ( V/V) dynamic characteristics dynamic response

dynamic Analysis of Tension Leg Platform for Offshore Wind Turbine Support as Fluid-Structure Interaction

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China Ocean Engineering 2011年第1期25卷 123-131页

作者：黄虎张社荣 North China University of Water Resources and Electric Power College of Civil Engineering Tianjin University

Tension leg platform （TLP） for offshore wind turbine support is a new type structure in wind energy utilization. The strong-interaction method is used in analyzing the coupled model, and the dynamic characteristics of the TLP for offshore wind turbine support are recognized. As shown by the calculated results： for the lower modes, the shapes are water＇s vibration, and the vibration of water induces the structure＇s swing; the mode shapes of the structure are complex, and can largely change among different members; the mode shapes of the platform are related to the tower＇s. The frequencies of the structure do not change much after adjusting the length of the tension cables and the depth of the platform; the TLP has good adaptability for the water depths and the environment loads. The change of the size and parameters of TLP can improve the dynamic characteristics, which can reduce the vibration of the TLP caused by the loads. Through the vibration analysis, the natural vibration frequencies of TLP can be distinguished from the frequencies of condition loads, and thus the resonance vibration can be avoided, therefore the offshore wind turbine can work normally in the complex conditions.

关键词： offshore wind turbine tension leg platform fluid structure interaction dynamic characteristics yaw resonance vibration

Analysis of Coupled Vibration characteristics of Wind Turbine Blade Based on Green's Functions

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Acta Mechanica Solida Sinica 2016年第6期29卷 620-630页

作者： Liang Li Xuanling Zhang Yinghui Li Department of Applied Mechanics School of Mechanics and Optoelectronics Physics Anhui University of Science and Technology School of Mechanics and Engineering Southwest Jiaotong University

This paper presents the analysis of dynamic characteristics of horizontal axis wind turbine blade, where the mode coupling among axial extension, flap vibration （out-of-plane bend- ing）, lead/lag vibration （in-plane bending） and torsion is emphasized. By using the Bernoulli-Euler beam to describe the slender blade which is mounted on rigid hub and subjected to unsteady aero- dynamic force, the governing equation and characteristic equation of the coupled vibration of the blade are obtained. Due to the combined influences of mode coupling, centrifugal effect, and the non-uniform distribution of mass and stiffness, the explicit solution of characteristic equation is impossible to obtain. An equivalent transformation based on Green＇s functions is taken for the characteristic equation, and then a system of integrodifferential equations is derived. The nu- merical difference methods are adopted to solve the integrodifferential equations to get natural frequencies and mode shapes. The influences of mode coupling, centrifugal effect, and rotational speed on natural frequencies and mode shapes are analyzed. Results show that：（1） the influence of bending-torsion coupling on natural frequency is tiny; （2） rotation has dramatic influence on bending frequency but little influence on torsion frequency; （3） the influence of bending-bending coupling on dynamic characteristics is notable at high rotational speed; （4） the effect of rotational speed on bending mode is tiny.

关键词： wind turbine blade mode coupling dynamic characteristics Green's function.

Effect of vehicle weight on natural frequencies of bridges measured from traffic-induced vibration

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Earthquake Engineering and Engineering Vibration 2003年第1期2卷 109-116页

作者： Chul-Young Kim Dae-Sung Jung Nam-Sik Kim Soon-Duck Kwon Maria Q.Feng Dept.of Civil & Envir.Eng. Myongji UniversityKorea Professor Dept.of Civil & Envir.Eng. Myongji UniversityKorea Research Associate Hyundai Institute of Construction Technology Hyundai E&C Co.Ltd.Korea Chief Researcher Dept.of Civil Engineering Chonbuk National UniversityKorea Professor Dept.of Civil & Envir.Eng. University of CaliforniaIrvineCaliforniaUSA Professor

Recently,ambient vibration test(AVT)is widely used tu estimate dynamic characteristics of large civil struc- *** characteristics ean be affected by various envirnnmental factors such as humidity,intensity of wind,and *** these environmental conditions,tire mass of vehicles may change the measured valnes when traffic-in- duced vibration is used as a source of AVT tor *** effect of vehicle mass on dynamic characteristics is investigated through traffic-induced vibration tests on three bridges;(1)three-span suspension bridge(128m+404m+128m),(2) five-span continuous steel box girder bridge(59m+3@ 95m+59m),(3)simply supported plate girder bridge(46m). Acceleration histories of each measurement location under normal traffic are recorded for 30 minutes at *** recor- ded histories are divided into individual vibrations and are combined into two groups aceording to the level of vibration;one by heavy vehicles such as trucks and buses and the other by light vehicles such as passenger *** processing of the two groups of signals shows that,for the middle and long-span bridges,the difference can be hardly detected,but,for the short span bridges whose mass is relatively small,the measured natural frequencies can change up to 5.4%.

关键词： ambient vibration test traffic induced vibration vehicle mass suspension bridge short-span bridge dynamic characteristics natural frequency

Semi-enclosed experimental system for coal spontaneous combustion for determining regional distribution of high-temperature zone of coal fire

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International Journal of Coal Science & Technology 2022年第5期9卷 124-137页

作者： Jingyu Zhao Hanqi Ming Tao Guo Yuxuan Zhang Jun Deng Jiajia Song Qiang Zeng Chi‑Min Shu School of Safety Science and Engineering Xi’an University of Science&TechnologyXi’an 710054China Shaanxi Key Laboratory of Prevention and Control of Coal Fire Xi’an University of Science&TechnologyXi’an 710054China Post-Doctoral Research Centre for Ecology Institute for Arid Ecology and EnvironmentXinjiang UniversityUrumqi 830046China Xi’an High-Tech Zone Emergency Management Bureau Xi’an 710065China Shaanxi Coal Chemical Industry Technology Research Institute Co.Ltd. Xi’an 710065China Department of Safety Healthand Environmental EngineeringNational Yunlin University of Science and TechnologyDouliou 64002YunlinTaiwanChina

Temperature variation and gas generation at diferent depths and positions in the coal combustion process were studied to determine the propagation and evolution of high temperature regions in the process of coal spontaneous *** study selected coal samples from Mengcun,Shaanxi Province,People’s Republic of China,and developed a semi-enclosed experimental system(furnace)for simulating coal *** thermal mass loss of coal samples under various heating rates(5,10,and 15℃/min)was analyzed through thermogravimetric analysis,and the dynamic characteristics of the coal samples were analyzed;the reliability of the semi-enclosed experimental system was verifed through the equal proportional method of fuzzy *** results reveal that the high-temperature zone is distributed nonlinearly from the middle to the front end of the furnace,and the temperatures of points in this zone decreased gradually as the layer depth *** apparent activation energy of the coal samples during combustion frst increased and then decreased as the conversion degree ***,the proportion of mass loss and the mass loss rate in the coal samples observed in the thermogravimetric experiment is consistent with that observed in the frst and second stages of the experiment conducted using the semi-enclosed *** research fndings can provide a theoretical basis for the prevention and control of hightemperature zones in coal combustion.

关键词： Coalfeld fre area Fuzzy migration path Semi-enclosed experimental system Thermogravimetric analysis dynamic characteristics

EXPERIMENTAL STUDY OF LOAD SENSING SYSTEM WITH LONG PIPES

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Chinese Journal of Mechanical Engineering 2005年第1期18卷 118-122页

作者： KongXiaowu QiuMinxiu WeiJianhua StateKeyLaboratoryofFluidPowerTransmissionandControl ZhejiangUniversityHangzhou310027China

A test platform is established as per the practical working condition ofelevating platform fire truck. The influences of pipes and load on dynamic characteristics ofload-sensing system are studied by series of step response experiments. Experimental results showthat the feedback pipe makes the most important influence on the dynamic response speed ofload-sensing system. Its internal diameter should be optimized for given length of pipe. On theother hand, the stability of load-sensing pump is improved as the length of input pipe increases ina certain range. The influence of input pipe on the dynamic response speed is caused mainly by thepressure-wave travel time in the input pipe.

关键词： Long pipe Load-sensing dynamic characteristics

STUDY ON THE COUPLED ELECTROMECHANICAL dynamicS OF ROTOR SYSTEM EQUIPPED WITH MAGNETIC BEARINGS

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Chinese Journal of Mechanical Engineering 2004年第1期17卷 93-96页

作者： ZhangGang ZhangJiansheng LiSongsheng YangXinzhou WuJianfeng WangXiping YuLie XieYoubai SchoolofElectromechanicalEngineeringandAutomation ShanghaiUniversityShanghai200072China TheoryofLubricationandBearingInstitute Xi＇anJiaotongUniversityXi＇an710049China

The influences of thrust magnetic bearing and journal tilt on dynamiccharacteristics of rotor system are studied mainly. The Outcome shows that the influences ofcoupling effects of thrust magnetic bearing and tilt of journal on critical rotational speeds ofsystem are very large, and the stability of system reduces greatly. That shows it is important thatthe influence of coupling effects of thrust and radial magnetic bearings due to the rotor tiltingmust be considered in the study of rotor-magnetic bearings system dynamic characteristics, and alsoshows it is important that the rotor is mounted and debugged in ideal alignment of magneticbearings.

关键词： Thrust magnetic bearing Journal tilt dynamic characteristics

2D SIMPLIFIED SERVO VALVE

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Chinese Journal of Mechanical Engineering 2003年第2期16卷 132-135页

作者： LiSheng RuanJian BurtonR UkrainetzP DepartmentofMechanicalEngineering ZheiiangUniversityofTechnologyHangzhou310014China DepartmentofMechanicalEngineering LlniwrsitvofSaskatchewan57CampusDriveSaskatoonSaskatchewanCanadaS7N5A9

A novel pilot stage valve called simplified 2D valve, which utilizes bothrotary and linear motions of a single spool, is presented. The rotary motion of the spoolincorporating hydraulic resistance bridge, formed by a damper groove and a crescent overlap opening,is utilized as pilot to actuate linear motion of the spool. A criterion for stability is derivedfrom the linear analysis of the valve. Special experiments are designed to acquire the mechanicalstiffness, the pilot leakage and the step response. It is shown that the sectional size of thespiral groove affects the dynamic response and the stiffness contradictorily and is also verysensitive to the pilot leakage. Therefore, it is necessary to establish a balance between the staticand dynamic characteristics in deciding the structural parameters. Nevertheless, it is possible tosustain the dynamic response at a fairly high level, while keeping the leakage of the pilot stage atan acceptable level.

关键词： servo valve piloted control dynamic characteristics