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OPTIMIZING DESIGN OF MECHANICAL SELF-CENTERING DEVICE FOR SUSPENSION HEIGHT

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Chinese Journal of Mechanical Engineering 2008年第6期21卷 69-75页

作者： cao min ZHANG Yongchao YU Fan School of Mechanical Engineering Shanghai Jiaotong University Shanghai 200240 China

Firstly, in view of the respective defects of existing self-centering devices for vehicle suspension height, the design scheme of the proposed mechanical self-centering device for suspension height is described. Taking the rear suspension of a certain light bus as a research example, the structures and parameters of the novel device are designed and ascertained. Then, the road excitation models, the performance evaluation indexes and the half-vehicle model are built, the simulation outputs of time and frequency domain are obtained with the road excitations of random and pulse by using MATLAB/Simulink software. So the main characteristics of the self-centering suspension are presented preliminarily. Finally, a multi-objective parameter design optimization model for the self-centering device is built by weighted sum approach, and optimal solution is obtained by adopting complex approach. The relevant choosing-type parameters for self-centering device components are deduced by using discrete variable optimal method, and the optimal results are verified and analyzed. So the performance potentials of the self-centering device are exerted fully in condition of ensuring overall suspension performances.

关键词： Suspension height Self-centering Vehicle height adjustment Optimizing design Multi-objective optimization

Micro-arc Oxidation Inverter Power Supply Based on the Limited Bipolar Soft-switch Control Method

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Chinese Journal of Mechanical Engineering 2009年第3期22卷 390-394页

作者： ZENG min CHEN Xiaohong cao Biao School of Mechanical and Automotive Engineering South China University of Technology Guangzhou 510640 China

In order to overcome many limitations of the conventional power supplies, such as ponderosity, big wastage, and simplex output characteristic, a dual-inverter power supply is designed to meet the different requirements of micro-arc oxidation. The main circuit structure and principle of the dual-inverter power supply for micro-arc oxidation is described, the control system and the control adjustment method are also introduced. The dual-inverter technology is adopted in micro-arc oxidation power supply. The limited bipolar control mode is applied in the power inverter circuit for adjusting the voltage, and various voltage waveform can be obtained by controlling the chopper circuit. Meanwhile, the control accuracy and response speed are improved greatly because of the higher inverter frequency. The power supply can output direct current（DC） waveform, DC pulse waveform, symmetry alternating current（AC） waveform, asymmetry AC waveform, and so on. Besides, the parameters such as pulse width, range, frequency, duty cycle can be adjusted. The experimental result shows that the power supply has many advantages, such as stable output, wonderful waveform consistency and obvious advantage in technique, and it can meet the requirements of micro-arc oxidation process fully.

关键词： micro-arc oxidation power supply inverter chopper limited bipolar

Thermodynamic and Economic Studies of a Combined Cycle for Waste Heat Recovery of Marine Diesel Engine

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Journal of Thermal Science 2022年第2期31卷 417-435页

作者： ZHANG Xinxin cao min HE Maogang WANG Jingfu MOE key laboratory of enhanced heat transfer and energy conservation Beijing University of TechnologyBeijing 100124China Beijing key laboratory of heat transfer and energy conversion Beijing University of TechnologyBeijing 100124China MOE Key Laboratory of Thermo-Fluid Science and Engineering School of Energy and Power EngineeringXi'an Jiaotong UniversityXi’an 710049China

In the present study,the thermodynamic and economic performance of a combined thermodynamic cycle formed by an ORC and a Kalina cycle,which can simultaneously recover waste heat of exhaust gas and cooling water of marine engine,has been *** typical marine engines are selected to be the waste heat *** economic indicators are used to analyze the economic performance of this combined thermodynamic cycle system with different marine engine load and under practical comprehensive operating condition of marine *** results of the present study show that the combined thermodynamic cycle system with R123 as organic working fluid has the best *** system with cis-butene has the worst economic *** practical comprehensive operating conditions of ships,R123 has the shortest Payback Periods,which are 8.51 years and 8.14 years for 8 S70 ME-C10.5 engine and 5G95 ME-C10.5 engine,***,payback Periods of Cyclopentane are 11.95 years and 11.90 *** above values are much shorter than 25 years which are the lifetime of a marine *** practical comprehensive operating conditions of ships,the combined cycle system can provide output power which is at least equivalent to 25%of engine *** that R123 will be phased out in near future,cyclopentane may be its good *** can be used safely by correct handling and installing according to manufacturer's instructions.

关键词： marine engine waste heat recovery combined thermodynamic cycle thermodynamic and economic study R123 cyclopentane

LU Invariants and Canonical Forms and SLOCC Classification of Pure 3-Qubit States

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Communications in Theoretical Physics 2006年第4期45卷 596-600页

作者： DI Yao-min cao Ya Department of Physics Xuzhou Normal University Xuzhou 221116 China

In this paper the entanglement of pure 3-qubit states is discussed. The local unitary （LU） polynomial invariants that are closely related to the canonical forms are constructed and the relations of the coefficients of the canonical forms are given. Then the stochastic local operations and classlcal communication （SLOCC） classification of the states are discussed on the basis of the canonical forms, and the symmetric canonical form of the states without 3-tangle is discussed. Finally, we give the relation between the LU polynomial invariants and SLOCC classification.

关键词： 3-qubit state canonical form LU invariant SLOCC classification

A Vector-based Cellular Automata Model for Simulating Urban Land Use Change

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Chinese Geographical Science 2015年第1期25卷 74-84页

作者： LU Yi cao min ZHANG Lei School of Geographic Science Nanjing Normal University Jiangsu Administration of Surveying Mapping and Geoinformation

Cellular Automata(CA) is widely used for the simulation of land use changes. This study applied a vector-based CA model to simulate land use change in order to minimize or eliminate the scale sensitivity in traditional raster-based CA model. The cells of vector-based CA model are presented according to the shapes and attributes of geographic entities, and the transition rules of vector-based CA model are improved by taking spatial variables of the study area into consideration. The vector-based CA model is applied to simulate land use changes in downtown of Qidong City, Jiangsu Province, China and its validation is confirmed by the methods of visual assessment and spatial accuracy. The simulation result of vector-based CA model reveals that nearly 75% of newly increased urban cells are located in the northwest and southwest parts of the study area from 2002 to 2007, which is in consistent with real land use map. In addition, the simulation results of the vector-based and raster-based CA models are compared to real land use data and their spatial accuracies are found to be 84.0% and 81.9%, respectively. In conclusion, results from this study indicate that the vector-based CA model is a practical and applicable method for the simulation of urbanization processes.

关键词： vector-based Cellular Automata(CA) land use change transition rule spatial accuracy Qidong City

Solutions for the Prescribing Mean Curvature Equation

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Acta Mathematicae Applicatae Sinica 2008年第3期24卷 497-510页

作者： Dao-min cao Shuang-jie Peng Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China School of Mathematics and Statistics Central China Normal University Wuhan 430079 China

By variational methods, for a kind of Yamabe problem whose scalar curvature vanishes in the unit ball BN and on the boundary S^N-1 the mean curvature is prescribed, we construct multi-peak solutions whose maxima are located on the boundary as the parameter tends to 0^＋ under certain assumptions. We also obtain the asymptotic behaviors of the solutions.

关键词： Mean curvature critical point concentrating solutions

Intraspecific trait variation of woody species reduced in a savanna community,southwest China

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Plant Diversity 2022年第2期44卷 163-169页

作者： Lubing Liu Jie Yang min cao Qinghai Song CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesYunnan 666303China University of Chinese Academy of Sciences Beijing 100049China

Plants deploy various ecological strategies in response to environmental *** many forest ecosystems,plants have been reported to have notable inter-and intra-specific trait variation,as well as clear phylogenetic signals,indicating that these species possess a degree of phenotypic plasticity to cope with habitat variation in the *** communities,however,grow in an open canopy structure and exhibit little species diversification,likely as a result of strong environmental *** this study,we hypothesized that the phylogenetic signals of savanna species would be weak,the intraspecific trait variation(ITV)would be low,and the contribution of intraspecific variation to total trait variance would be reduced,owing to low species richness,multiple stresses and relatively homogenous community *** test these hypotheses,we sampled dominant woody species in a dry-hot savanna in southwestern China,focusing on leaf traits related to adaptability of plants to harsh conditions(yearround intense radiation,low soil fertility and seasonal droughts).We found weak phylogenetic signals in leaf traits and low ITV(at both individual and canopy-layer levels).Intraspecific variation(including leaf-,layer-and individual-scales)contributed little to the total trait variance,whereas interspecific variation and variation in leaf phenology explained substantial *** study suggests that intraspecific trait variation is reduced in savanna ***,our findings indicate that classifying species by leaf phenology may help better understand how species coexist under similar habitats with strong stresses.

关键词： Phylogenetic signal Savanna Intraspecific trait variation(ITV) Leaf phenology Coexistence

Soil seed banks along elevational gradients in tropical, subtropical and subalpine forests in Yunnan Province, southwest China

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Plant Diversity 2017年第5期39卷 273-286页

作者： Xiaqin Luo min cao min Zhang Xiaoyang Song Jieqiong Li Akihiro Nakamura Roger Kitching Key Laboratory of Tropical Forest Ecology Xishuanghanna Tropical Botanical GardenChinese Academy of Sciences666303 YunnanChina University of Chinese Academy of Sciences 100049BeijingChina Griffith School of Environment and Environmental Futures Research Institute Griffith UniversityNathan QLD 4111BrisbaneAustralia

Soil seed banks are a vital part of ecosystems and influence community dynamics and *** soil seed banks in different habitats have been reported, how soil seed banks vary with elevational gradients in different climatic zones is still unknown. This paper investigates seed density,species composition and nonconstituent species of forest soil seed banks in Yunnan Province, southwest China. Similarity between the soil seed bank and standing vegetation was also examined. We collected soil samples from sites spanning 12 elevations in tropical rain forests, subtropical evergreen broadleaved forests and subalpine coniferous forests, and transported them to a glasshouse for germination trials for species identification. The soil seed banks of tropical and subtropical forests had much higher seed densities and species richness than those of subalpine forests. Seeds of woody species dominated the soil seed banks of tropical and subtropical forests, while herbs dominated those of subalpine *** nonconstituent species in the soil seed banks were all herbs and were most abundant in tropical forests, followed by subtropical forests but were completely absent from subalpine forests.

关键词： Elevational gradient Soil seed bank Standing vegetation Subalpine forest Subtropical forest Tropical forest

Modeling Method of Multi-Energy Systems Based on LSTM Algorithm

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1701-1709页

作者： Di Qiu Fei Chen Dong Liu min cao Siyang Liu Shanghai Jiao Tong University Shanghai 200240China Yunnan Power Grid Co. Ltd

The development of the Energy Internet has improved the efficiency of energy utilization and promoted sustainable development of power and energy *** multi-energy system modeling considering the dynamic process of transmission line is one of the key research points of Energy Internet operation *** the energy circuit theory,the lumped parameter model of natural gas pipelines is built and the dynamic characteristic parameters under the control instruction are *** with dynamic characteristic parameters,the long short-term memory(LSTM)neural network is designed to fit the natural gas pipeline dynamic process into discrete linear time-varying(LTV)*** with the equations,an energy hub method is used to build a control model of industrial parks with multi-energy distribution *** the rolling optimal control strategy given in this paper,the model is solved by the Matlab-Yalmip solver and rolling control instructions of each energy conversion unit are ***,the case study demonstrates that the LSTM neural network-based modeling method presented in this paper can accurately fit the dynamic process of a natural gas pipeline *** rolling control model of the multi-energy system can improve the efficiency of energy utilization,exhibit the transmission line status constraints during the optimization control process and improve reliability of the multi-energy system operation.

关键词： Energy hub LSTM multi-energy supply system pipeline system modeling