检索结果-南通市图书馆

Prediction of pilot workload in helicopter landing after one engine failure

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2020年第12期33卷 3112-3124页

作者： zhiming yu Xufei YAN Renliang CHEN National Key Laboratory of Rotorcraft Aeromechanics Nanjing University of Aeronautics and AstronauticsNanjing 210016China Intelligent Robot Research Center Zhejiang LabHangzhou 310000China

This paper presents a method to predict the pilot workload in helicopter landing after one engine *** landing procedure is simulated numerically via applying nonlinear optimal control method in the form of performance index,path constraints and boundary conditions based on an augmented six-degree-of-freedom rigid-body flight dynamics model,solved by collocation and numerical optimization ***-60 A helicopter is taken as the sample for the demonstration of landing after one engine *** numerical simulation was conducted to find the trajectory of helicopter and the controls from pilot for landing after one engine failure with different performance index considering the factor of pilot *** reasonable performance index and corresponding landing trajectory and controls are obtained by making a comparison with those from the flight test ***,the pilot workload is evaluated based on wavelet transform analysis of the pilot control *** workloads of pilot control activities for collective control,longitudinal and lateral cyclic controls and pedal control during the helicopter landing after one engine failure are examined and compared with those of flight *** results show that when the performance index considers the factor of pilot workload properly,the characteristics of amplitudes and constituent frequencies of pilot control inputs in the optimal solution are consistent with those of the pilot control inputs in the flight ***,the proposed method provides a tool of predicting the pilot workload in helicopter landing after one engine failure.

关键词： Engine failure Nonlinear optimal control method Pilot control activity Pilot workload Wavelet transform analysis

Boundary value problems of discrete generalized Emden-Fowler equation

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2006年第10期49卷 1303-1314页

作者： yu Jianshe GUO zhiming College of Mathematics and Information Sciences Guangzhou University Guangzhou 510006 China College of Mathematics and Information Sciences Guangzhou University Guangzhou 510006 China

By using the critical point theory, some sufficient conditions for the existence of the solutions to the boundary value problems of a discrete generalized Emden-Fowler equation are obtained. In a special case, a sharp condition is obtained for the existence of the boundary value problems of the above equation. For a linear case, by the discrete variational theory, a necessary and sufficient condition for the existence, uniqueness and multiplicity of the solutions is also established.

关键词： discrete generalized Emden-Fowler equation, boundary value problem, Saddle Point Theorem, discrete variational theory.

Cavitation Erosion Corrosion Behaviour of Manganese-nickel-aluminum Bronze in Comparison with Manganese-brass

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2009年第6期25卷 758-766页

作者： Hong yu yugui Zheng zhiming Yao State Key Laboratory for Corrosion and Protection Institute of Metal Research Chinese Acadamy of Sciences Shenyang 110016 China

The cavitation erosion corrosion behaviour of ZQMn12-8-3-2 manganese-nickel-aluminum bronze and ZHMn55- 3-1 manganese-brass was investigated by mass loss, electrochemical measurements （polarization curves and electrochemical impedance spectroscopy） and the cavitation damaged surfaces were observed by scanning electron microscopy （SEM）. The results showed that ZQMn12-8-3-2 had better cavitation erosion resistance than ZHMn55-3-1. After the cavitation erosion for 6 h, the cumulative mass loss of ZQMn12-8-3-2 was about 1/3 that of ZHMn55-3-1. The corrosion current density of ZQMn12-8-3-2 was less than that of ZHMn55-3-1 under both static and cavitaiton condition. The free-corrosion potentials of ZQMn12-8-3-2 and ZHMn55-3-1 were all shifted in positive direction under cavitation condition compared to static condition. In the total cumulative mass loss under cavitation condition, the pure erosion played a key role for the two tested materials （74% for ZHMn55-3-1 and 60% for ZQMn12-8-3-2）, and the total synergism between corrosion and erosion of ZQMn12-8-3-2 （39%） was larger than that of ZHMn55-3-1 （23%）. The high cavitation erosion resistance of ZQMn12-8-3-2 was mainly attributed to its lower stacking fault energy （SFE）, the higher microhardness and work-hardening ability as well as the favorable propagation of cavitation cracks for ZQMn12-8-3-2, i.e., parallel to the surface rather than perpendicular to the surface for ZHMn55-3-1.

关键词： Cavitation erosion Marine propeller Manganese-nickel-aluminum bronze Manganese-brass Synergism Work-hardening ability Stacking fault energy

Effect of Different Reinforcing Fillers on Properties,Interfacial Compatibility and Weatherability of Wood-plastic Composites

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2019年第2期16卷 337-353页

作者： Xiaoqian Wang zhiming yu Armando G.McDonald MOE Key Laboratory of Wooden Material Science and Application Beijing Forestry UniversityQinghua East Road No.35Beijing 100083China Renewable Materials Program Department of ForestRangelandand Fire SciencesUniversity of Idaho875 Perimeter Drive MS 1133MoscowIdaho 83844-1133USA

Utilization of biochar in plastic based blends offers a sustainable way to renewable materials as well as value-added use of wood *** investigate the interfacial compatibility and weatherability properties of biochar composites,four types of Wood-Plastic Composites(WPC)were prepared by an extrusion *** mechanical properties,water absorptions,thermal and viscoelastic properties,and rheological behavior of the composites were also *** decolorizing carbon(NA)composite melts showed the higher modulus and viscosity,indicating better melt *** NA composites performed the best in tensile properties(strength of 2&6 MPa and modulus of 3.4 GPa)and had strong interfacial interaction between particles and the *** degree of HDPE crystallinity in the biochar and carbon composites decreased relative to Douglas-fir(DF)composites,while the thermal properties of the composites improved compared with DF *** the water resistance,the DF composites displayed the highest water absorption(3.7%)and thickness swell(2.9%).During accelerated weathering tests,longer exposure time increased the color change and lightness,especially for DF *** and biochar composites resulted in improved *** study opens up a pathway to utilize effectively the renewable biochar as reinforcing filler in WPC in outdoor applications.

关键词： biochar interfacial compatibility accelerated weathering wood-plastic composites

Research on Trim Control of Compound High Speed Helicopter

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

Transactions of Nanjing University of Aeronautics and Astronautics 2019年第3期36卷 449-458页

作者： yu zhiming KONG Weihong CHEN Renliang National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics Nanjing University of Aeronautics and Astronautics

An investigation is conducted on optimizing the control allocation for trimmed flight on the compound *** compound helicopter features a single main rotor,a vectored thrust ducted propeller(VTDP)and lifting *** to the redundant controls for thrust,elevator deflection,and differential and symmetric flap deflection,there is a wide range of trim solutions in forward flight for compound helicopter.A method is developed to calculate optimal trim ***,aerodynamics models for deferent subsystems of the compound helicopter are conducted,which consider the mutual interaction of each ***,a flight dynamics model is developed based on which the method of trim optimization is ***,the method is demonstrated using a compound helicopter UH 60L/*** trim optimization of flight conditions from hover to 370 km/h is conducted using the optimization *** controls,fuselage attitudes as well as the allocation of lift and thrust along with the flight speed are obtained.

关键词： compound helicopter trim control optimization

supported by the National Natural Science Foundation ofChina(Grant No.41476131),the Innovation Program of Shanghai Municipal Education Commission(Grant No.14ZZ143), the Shanghai Universities Plateau Discipline Project of Marine Sciences and the Peak Discip

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2017年第2期60卷 391-396页

作者： LI Jing SUN Lei yu zhiming SONG XiuXian Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChina Academy of Science Laboratory of Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and Technology College of Earth Sciences University of Chinese Academy of Sciences College of Environmental Science and Engineering Ocean University of China

Prevention of annual"green tides"caused by blooms of the green macroalga Ulva prolifera,which have occurred in the Yellow Sea since 2007,has received much *** evidence indicates that micro-propagules on the rafts used for Porphyra yezoensis aquaculture along the coastline of Jiangsu Province in China,were the primary source of these green *** this study,we investigated the effectiveness of a silicone antifouling coating for preventing the adhesion and germination of *** micro-propagules on bamboo and nylon ropes,which have been used in rafts for *** *** results demonstrated that a coating of silicone(Sylgard 184)containing 1.0 wt.%sodium benzoate(NaB)could reduce the adhesion rate to<5%and completely inhibited the growth of *** propagules on the coated *** bamboo and nylon ropes with NaB-incorporated silicone thus proved a potentially effective method for controlling the initial biomass accumulation of ***.

关键词： Ulva prolifera Green tide Silicone Sodium benzoate Biofouling

Profiles of and variations in aluminum species in PAC-MC used for the removal of blooming microalgae

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2021年第8期33卷 76-82页

作者： Xueyi Dong Xihua Cao Wenbin Jiang Xiuxian Song zhiming yu Shitao yu College of Chemical Engineering Qingdao University of Science and TechnologyQingdao 266042China CAS Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChinese Academy of SciencesQingdao 266071China Functional Laboratory of Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China University of Chinese Academy of Science Beijing 100049China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao266071China

Polyaluminum chloride modified clay(PAC-MC)is a safe and efficient red tide control agent that has been studied and applied *** it is well known that the distribution of hydrolytic aluminum species in PAC affects its flocculation,little is known about the influence of particulars aluminum species on the microalgae removal efficiency of PAC-MC;this lack of knowledge creates a bottleneck in the development of more efficient MCs based on aluminum *** ferron method was used in this study to quantitatively analyze the distributions of and variations in different hydrolytic aluminum species during the process of microalgae removal by *** results showed that Ala,which made up 5%–20%of the total aluminum,and Alp,which made up 15%–55%of the total aluminum,significantly affected microalgae removal,with Pearson’s correlation coefficients of 0.83 and 0.89,*** of the aluminum in the PAC-MC sank rapidly into the sediments,but the rate and velocity of settlement were affected by the dose of modified *** optimal dose of PAC-MC for precipitating microalgae was determined based on its aluminum *** results provide guidance for the precise application of PAC-MC in the control of harmful algal blooms.

关键词： Modified clay Red tide Aluminum species Microalgal removal efficiency Ecological safety

Flocculation of Ulva microscopic propagules using modified clay:a mesocosm experiment

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2020年第4期38卷 1283-1291页

作者： LI Jing SONG Xiuxian FAN Xin yu zhiming CAS Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory of Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China University of Chinese Academy of Sciences Beijing 100049China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

Microscopic propagules of Ulva species(UMPs)spread on Subei Shoal are believed to play a significant role in the formation of the Yellow Sea green *** laboratory and ship-based studies indicated that modified clay(MC)can effectively remove UMPs from the water column and restrict their *** evaluate the effectiveness of this method under natural conditions,a mesocosm experiment was conducted on the Zhugensha sandbank on Subei *** results show that the suspended particles on the sandbank would partially disturb the flocculation process between the MC and ***,the MC at a proper dose could effectively remove UMPs from the water column and decrease the adhesion and germination of UMPs on the nylon ropes that comprised the mariculture rafts by>75%.This method was proven a potential strategy to restrict the initial biomass accumulation of green algae on Subei ***,field trials in larger time-space scales are still needed to assess the efficiency of this method when used in the open sea.

关键词： green tide Ulva modified clay microscopic propagules

Diatom-based dissolved inorganic nitrogen reconstruction in the Changjiang River estuary and its adjacent areas

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2023年第4期41卷 1464-1480页

作者： Xin FAN Fangjin CHENG zhiming yu Xiuxian SONG College of Naval Architecture and Port Engineering Shandong Jiaotong UniversityWeihai 264209China CAS Key Laboratory of Marine Ecology and Environmental Sciences Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory of Marine Ecology and Environmental Science Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China University of Chinese Academy of Sciences Beijing 100049China Environmental Monitoring Center of Qingdao Qingdao 266003China

A five-component weighted average partial least squares(WA-PLS)calibration model was developed by analysing diatom assemblages in 34 surface sediment samples(collected in 2015)from the Changjiang River estuary(CRE)and its adjacent areas to infer dissolved inorganic nitrogen(DIN)*** additional sets of surface sediment diatoms and corresponding upper water DIN data(collected in 2012)were used to evaluate the accuracy of the model,and the relationship between observed and diatom-inferred DIN(DI-DIN)values(R2=0.85)illustrated the strong performance of the transfer function,indicating that precise reconstructions of former DIN are *** diatom-DIN transfer function was applied to the diatom record from a sediment core DH8-2(1962‒2012)collected in the Fujian-Zhejiang area south of the *** reconstruction based on the DI-DIN model showed a significant DIN increase from 1962-2012,reflecting the influence of human activities on the very large increase in *** distinct periods can be seen from the changes in DIN and diatom *** the 1962-1972 period,the DIN content was relatively low,with an average of 5.94μmol/L,and more than 80%of the diatom species identified were benthic *** the 1972-2004 period,as the impact of human activities intensified,large nutrient inputs caused the DIN content to increase,with an average of 8.25μmol/*** nutrient inputs also caused a significant change in the nutrient components and a distinct increase in small planktonic *** the 2004-2012 period,the DIN content continued to rise,fluctuating at approximately 10μmol/L.A continuous increase in the frequency of planktonic taxa(up to 65.48%)indicated that eutrophication was further intensified,which was confirmed by the transformation from diatom-induced red tide to dinoflagellate-induced red tide during this period.

关键词： Changjiang River estuary dissolved inorganic nitrogen(DIN)reconstruction diatoms transfer function