检索结果-南通市图书馆

Bionic Quadruped Robot Dynamic Gait Control Strategy Based on Twenty Degrees of Freedom

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2018年第1期5卷 382-388页

作者： Dawei Gong Peng Wang Shuangyu Zhao Li Du yu duan University of Electronic Science and Technology Chengdu 611731 China

Quadruped robot dynamic gaits have much more advantages than static gaits on speed and efficiency, however high speed and efficiency calls for more complex mechanical structure and complicated control algorithm. It becomes even more challenging when the robot has more degrees of *** a result, most of the present researches focused on simple robot, while the researches on dynamic gaits for complex robot with more degrees of freedom are relatively limited. The paper is focusing on the dynamic gaits control for complex robot with twenty degrees of freedom for the first time. Firstly, we build a relatively complete 3 D model for quadruped robot based on spring loaded inverted pendulum(SLIP) model, analyze the inverse kinematics of the model, plan the trajectory of the swing foot and analyze the hydraulic drive. Secondly, we promote the control algorithm of one-legged to the quadruped robot based on the virtual leg and plan the state variables of pace gait and bound gait. Lastly, we realize the above two kinds of dynamic gaits in ADAMS-MATLAB joint simulation platform which testify the validity of above method.

关键词： Degree of freedom dynamic gait foot trajectory quadruped robot spring loaded inverted pendulum(SLIP)

The Hot Spots in Cereal Rusts and Powdery Mildew Research

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2014年第2期13卷 229-232页

作者： CHEN Wan-quan duan Xia-yu JIA Editorial Board Institute of Plant Protection Chinese Academy of Agricultural Sciences

Cereal crops, including wheat, barley, oats, rye, etc., are the major sources of calories and proteins for most of the people in the world as well as in China. Cereal rusts and powdery mildews are very important diseases occurred on the cereal crops, which caused yield losses at 5-10% in general and even more than 30% while severe epidemics occurred. In recent years, with the global climate change, change of cultivation system and evolution of the pathogens, the world is facing great challenges caused by cereal diseases.

关键词： The Hot Spots in Cereal Rusts and Powdery Mildew Research than

Idealization Second Quantization of Composite Particles

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2001年第11期36卷 525-530页

作者： ZHOU duan-Lu yu Si-Xia SUN Chang-Pu Institute of Theoretical Physics Academia SinicaBeijing 100080China Institute of Theoretical PhysicsAcademia SinicaBeijing 100080China Institute of Theoretical PhysicsAcademia SinicaBeijing 100080China

A practical method is developed to deal with the second quantization of the many-body system containing the composite *** our treatment,the modes associated with composite particles are regarded approximately as independent ones compared with those of unbound *** field operators of the composite particles thus arise naturally in the second quantization *** be emphasized,the second quantization Hamiltonian has the regular structures which correspond clearly to different physical processes.

关键词： second quantization,composite particles

Stable and highly efficient perovskite solar cells:Doping hydrophobic fluoride into hole transport material PTAA

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5期15卷 4431-4438页

作者： Chao yu Buyue Zhang Chen Chen Jintao Wang Jian Zhang Ping Chen Chuannan Li yu duan State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China College of Science Changchun University of Science and TechnologyChangchun 130012China

Perovskite solar cells(PSCs)have rapidly developed in the past few years,with a record efficiency exceeding 25%.However,the long-term stability of PSCs remains a challenge and limits their practical *** high-performance PSCs have an n-i-p device architecture employing 4-tert-butylpyridine(t-BP)and bis(trifluoromethane)sulfonimide lithium salt(Li-TFSI)as bi-dopants for the hole-transporting layer(HTL).However,the hygroscopicity of Li-TFSI and low boiling point of t-BP negatively impact the moisture stability of these PSC ***,we report the use of the fluorine-containing hydrophobic compound tris(pentafluorophenyl)phosphine(35FP)as a dopant for poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine](PTAA).With better hydrophobicity and stability than undoped PTAA,a PSC device containing 35FP-doped PTAA demonstrated improved charge transport properties and reduced trap density,leading to a significant enhancement in *** addition,the long-term stability of a 35FP-doped PTAA PSC under air exposure without encapsulation was demonstrated,with 80%of the initial device efficiency maintained for 1,000 *** work provides a new approach for the fabrication of efficient and stable PSCs to explore hydrophobic dopants as a substitute for hydrophilic Li-TFSI/t-BP.

关键词： perovskite solar cells additive engineering long-term stability hydrophobic dopant

The Connection between the Sea Surface Height Anomaly Preceding the Indian Ocean Dipole and Summer Rainfall in China

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

Atmospheric and Oceanic Science Letters 2015年第4期8卷 238-243页

作者： duan Xin-yu LIU Na LI Shuanglin College of Atmospheric Science Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technology Nansen-Zhu International Research Centre Institute of Atmospheric Physics Chinese Academy of Sciences Climate Change Research Center Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

The sea surface height anomaly(SSHA) signals leading the fall Indian Ocean Dipole(IOD) are investigated. The results suggest that, prior to the IOD by one year, a positive SSHA emerges over the western-central tropical Pacific(WCTP), which peaks during winter(January-February-March, JFM), persists into late spring and early summer(April-May-June, AMJ), and becomes weakened later on. An SSHA index, referred as to SSHA_WCTP, is defined as the averaged SSHA over the WCTP during JFM. The index is not only significantly positively correlated with the following-fall(September-October-November, SON) IOD index, but also is higher than the autocorrelation of the IOD index crossing the two different seasons. The connection of SSHA_ WCTP with following-summer rainfall in China is then explored. The results suggest that higher(lower) SSHA_ WCTP corresponds to increased(reduced) rainfall over southern coastal China, along with suppressed(increased) rainfall over the middle–lower reaches of the Yangtze River, North China, and the Xinjiang region of northwestern China. Mechanistically, following the preceding-winter higher(lower) SSHA_WCTP, the South Asia High and the Western Pacific Subtropical High are weakened(intensified), which results in the East Asian summer monsoon weakening(intensifying). Finally, the connection between SSHA_WCTP and El Ni?o-Southern Oscillation(ENSO) is analyzed. Despite a significant correlation, SSHA_WCTP is more closely connected with summer rainfall. This implies that the SSHA_WCTP index in the preceding winter is a more effective predictor of summer rainfall in comparison with ENSO.

关键词： sea surface height Indian Ocean Dipole summer rainfall in China ENSO

Temperature Drop Model Based on Discrete Element Method for Simulating Damage of Bio-Cemented Sand by Cold Wave

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2019年第6期24卷 789-798页

作者： duan yu KIM Cholgyong XU Guobin State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300350China School of Civil Engineering Tianjin UniversityTianjin 300350China School of hydraulic Engineering Hydraulic and Dynamic of Hamhung UniversityHamhungDPRK

The microbially cemented sand(MCS)material is a new building material with a broad research prospect,although the nationwide cold wave affects the mechanical properties of the material in the practical *** microstructure of MCS is obtained by computed tomography(CT)and scanning electron microscope(SEM);the thermodynamic mathematical model is established by considering the particle shapes and bonding state based on direct element method(DEM).By studying the damage of temperature drop amplitude and cooling duration to MCS material under the effect of cold wave,the following conclusions are *** a given temperature drop range,an increased cooling time can aggravate the material *** addition,a rapid drop in temperature can cause serious damage to the *** cracks generated by the temperature stress propagate in the direction of the weaker component of the *** DEM model can be better used to analyze the damage of the MCS structure induced by cold wave.

关键词： cold wave microbial-induced calcium carbonate precipitation(MICP) calcite discrete element method(DEM) crack

Water Sources of Dominant Species in Three Alpine Ecosystems on the Tibetan Plateau,China

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2008年第3期50卷 257-264页

作者： De-yu duan Hua Ouyang Ming-Hua Song Qi-Wu Hu Institute of Geographical Sciences and Natural Resources Research the Chinese Academy of Sciences Beijing 100101 China Graduate University of the Chinese Academy of Sciences Beijing 100039 China

Plant water sources were estimated by two or three compartment linear mixing models using hydrogen and oxygen isotope （δD and δ^18O） values of different components such as plant xylem water, precipitation and river water as well as soil water on the Tibetan Plateau in the summer of 2005. Four dominant species （Quercus aquifolioides, Pinus tabulaeformis, Salix rehderiana and Nitraria tangutorum） in three typical ecosystems （forest, shrub and desert） were investigated in this study. Stable isotope ratios of the summer precipitations and the soil water presented variations in spatial and temporal scales. δ^18O values of N. tangutorum xylem water were constant in the whole growth season and very similar to those of deep soil water. Water sources for all of the plants came from both precipitations and soil water. Plants switched rapidly among different water sources when environmental water conditions changed. Rainwater had different contributions to the plants, which was influenced by amounts of precipitation. The percentage of plant xylem water derived from rainwater rose with an increase in precipitation. Water sources for broad-leaved and coniferous species were different although they grew in the same environmental conditions. For example, the broad-leaved species Q. aquifolioides used mainly the water from deep soil, while 92.5% of xylem water of the coniferous species P. tabulaeformis was derived from rainwater during the growth season. The study will be helpful for us to fully understand responses of species on the Tibetan Plateau to changes in precipitation patterns, and to assess accurately changes of vegetation distribution in the future.

关键词： δD δ^18O precipitation river water soil water Tibetan Plateau

Swelling of Spherical Polyelectrolyte Gels

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第9期42卷 1386-1392,I0009页

作者： Ming-yu duan Jia-Dong Chen Yi-Ming Liu Zhao-Feng Peng Guang Chen Department of Advanced Manufacturing and Robotics College of EngineeringPeking UniversityBeijing 100871China

Polyelectrolyte(PE)gels,distinguished by their unique stimuli-responsive swelling behavior,serve as the basis of broad applications,such as artificial muscles and drug *** this work,we present a theoretical model to analyze the electrostatics and its contribution to the swelling behavior of PE gels in salt *** minimizing the free energy of PE gels,we obtain two distinct scaling regimes for the swelling ratio at equilibrium with respect to the salt *** compare our predictions for the swelling ratio with experimental measurements,which show excellent *** addition,we employ a finite element method to assess the applicability range of our theoretical model and *** anticipate that our model will also provide valuable insights into drug adsorption and release,deformation of red blood cells,4D printing and soft robotics,where the underlying mechanism of swelling remains enigmatic.

关键词： Gels Polyelectrolytes Swelling Stimuli-responsive Electrostatic interaction Cell model

LSTM neural network for solar radio spectrum classification

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2019年第9期19卷 137-148页

作者： Long Xu Yi-Hua Yan Xue-Xin yu Wei-Qiang Zhang Jie Chen Ling-yu duan Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of SciencesBeijing100101China College of Mathematics and Statistics Shenzhen UniversityShenzhen518060China3National Engineering Lab for Video TechnologyPeking UniversityBeijing100871China

A solar radio spectrometer records solar radio radiation in the radio waveband. Such solar radio radiation spanning multiple frequency channels and over a short time period could provide a solar radio spectrum which is a two dimensional image. The vertical axis of a spectrum represents frequency channel and the horizontal axis signifies time. Intrinsically, time dependence exists between neighboring columns of a spectrum since solar radio radiation varies continuously over time. Thus, a spectrum can be treated as a time series consisting of all columns of a spectrum, while treating it as a general image would lose its time series property. A recurrent neural network(RNN) is designed for time series analysis. It can explore the correlation and interaction between neighboring inputs of a time series by augmenting a loop in a *** paper makes the first attempt to utilize an RNN, specifically long short-term memory(LSTM), for solar radio spectrum classification. LSTM can mine well the context of a time series to acquire more information beyond a non-time series model. As such, as demonstrated by our experimental results, LSTM can learn a better representation of a spectrum, and thus contribute better classification.

关键词： deep learning long short-term memory(LSTM) classification solar radio spectrum solar burst detection