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Effect of mixture sowing on biomass allocation in the artificially-planted pastures, southeastern Tibetan

Journal of Mountain science 2019年第1期16卷 54-63页

作者： CHEN Fan XIA Hao QIN Xiao-jing power China Guiyang engineering corporation limited Key Laboratory of Mountain surface Processes and Ecological Regulation Institute of Mountain Hazards and Environment Chinese Academy of Science University of Chinese Academy of sciences

Artificial planting is an important measure to promote the restoration of degraded grassland and protect the ecological environment. The objectives of the current study were to investigate the allocation pattern between aboveground biomass(AGB) and belowground biomass(BGB) in different seeding types of artificially-planted pastures. We explored the variation in biomass and the relationship between above-and belowground biomass in four artificiallyplanted pastures with one species from Elymus nutans Griseb(EN, perennial), Elymus sibiricus Linn(Es, perennial), Medicago sativa Linn(Ms, perennial), and Avena sativa Linn(As, annual) and in six artificially-planted communities with mixtures of two species by seeding ratio 1:1 from the abovementioned grasses(EN + As, Ms + As, EN + Es, Ms + EN, Ms + Es, As + Es) in 2015 and 2016. The results showed that E. nutans is the most productive species with the highest biomass production among the single crops. Ms + Es was the most productive group in 2015, while the group with the highest biomass production changed to As + Es in 2016. AGB was positively correlated to BGB in the surface soil layer in the first year, but positively related to BGB in the subsoil layer in the second year. In the early stageof artificial grassland succession, plants allocated more biomass to aboveground parts, with a root to shoot(R/s) ratio of 1.98. The slope of the log-log relationship between AGB and BGB was 1.07 in 2016, which is consistent with the isometric theory. Different sowing patterns strongly affected the accumulation and allocation of biomass in artificiallyplanted grassland, E. sibiricus was the suitable plant in the alpine regions, which will be conducive to understanding vegetation restoration and plant interactions in the future.

关键词： Artificial grassland Aboveground biomass Belowground biomass Mono seeding Mixed seeding Elymus

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DsC AND TEM sTUDY OF ULTRA HIGH sTRENGTH ALUMINUM ALLOY

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Acta Metallurgica sinica(English Letters) 2004年第4期17卷 554-559页

作者： G.s.Xie Y.Zeng H.Ding Hunan Electric power Test & Research Institute Changsha 410007 ChinaMaterial Department Central South University Changsha 410083 ChinaMaterial Department Wuhan University Wuhan 430072 China

In this paper, the effect of RRA treatment on the microstructure evolution of a high strength aluminum alloy was investigated using DsC, TEM and sADP technology. The results show that the precipitation resulting from RRA is extremely fine and distributed homogeneously in the grains, being slightly coarser and more stable than that of T6 temper. While, the grain-boundary precipitation is very close to that of the alloy at T73 temper, being coarse and discontinuous. High retrogression temperature and long retrogression time leads to a more stable microstructure after re-aging.

关键词： DsC TEM RRA Al-Zn-Mg-Cu alloy

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Effects of swirl and hot streak on thermal performances of a high-pressure turbine

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Chinese Journal of Aeronautics 2023年第5期36卷 250-267页

作者： shenghui ZHANG shuiting DING Peng LIU Tian QIU National Key Laboratory of science and Technology on Aero-Engine Aero-thermodynamics School of Energy and Power EngineeringBeihang UniversityBeijing 100191China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

Advanced civil aero-engines tend to adopt lean burn combustors to meet emission *** exit of a lean burn combustor experiences highly non-uniformities in both temperature(Hot streak,Hs)and flow(swirl).This paper presents a numerical investigation on the behaviors of a High-Pressure(HP)turbine under a combined effect of swirl and hot *** investigation was conducted on a GE-E3 HP turbine with unsteady numerical simulations,which considered the realistic clocking position of the HP Nozzle Guide Vane(NGV)relative to the *** influences of swirl orientations on the Hs migration and thermal performances on the blade surface were *** indicate that,inside the NGV passage,the swirl’s induced incidence angle effect dominates the Hs radial *** transversal movement of Hs follows the cross flow and thus makes itself approach the suction side(ss)and keep away from the Pressure side(Ps)as passing through the NGV,so that Hs near the ss is more influenced by the incidence angle effect than that near the *** for the heat transfer,swirl affects the Heat Transfer Coefficient(HTC)on the NGV’s Ps and ss mainly through the incidence angle *** from the NGV,the inlet swirl and Hs have limited effect on the HTC on the rotor blade’s Ps,while on the rotor blade’s ss,the original vortex system dominates;therefore,the inlet non-uniformities merely enhance the HTC on the ss rather than alter its distribution characteristics.

关键词： High-pressure turbine Hot streak Thermal performances swirl Orientations Vortex

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solar Flux Measuring and Optical Efficiency Forecasting of the Linear Fresnel Reflector Concentrator after Dust Accumulation

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Journal of Thermal science 2022年第3期31卷 663-677页

作者： ZHAO Xiaoyan YAN suying ZHANG Na ZHAO Ning GAO Hongwei College of Energy and power Engineering Inner Mongolia University of TechnologyHohhot010051China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China University of Chinese Academy of sciences Beijing100049China

The linear Fresnel reflector concentrator(LFRC)is widely used in the field of solar energy utilization due to its simple structure,low cost,and excellent wind ***,the LFRC operates outdoors all year round,and the dust accumulation on the mirror will reduce the optical efficiency of the system,so it needs to be perfected and *** this paper,a focal plane energy flux experimental device was designed to test the energy flux of the system under different dust accumulation *** results indicate that,the dust density on the mirror increased and the energy flux on the focal plane decreased with increase of dust accumulation *** undergoing dust accumulation for 35 days,the dust density on the mirror reached 4.33 g/m^(2)and the average energy flux on the focal plane decreased to 1.78 kW/m^(2).Additionally,the variation of reflectivity caused by dust accumulation on mirror was taken as the quantitative index,and a prediction model for the impact of dust on the optical efficiency of the system was *** results will provide guidance for improving the optical efficiency of the LFRC.

关键词： dust accumulation energy flux linear Fresnel reflector concentrator optical efficiency forecast

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Numerical simulation of residual stress field induced by laser shock processing with square spot

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Journal of shanghai University(English Edition) 2011年第6期15卷 553-556页

作者：曹子文车志刚邹世坤费群星 National Key Laboratory of science and Technology on power Beam Processes Beijing Aeronautical Manufacturing technology Research Institute

Laser shock processing（LsP）,also known as laser peening,is a novel surface treatment technique in the past few *** residual stresses which imparted by LsP are very important for improving fatigue,corrosion and wea rresistance of *** element analysis（FEA） simulation using ABAQUs software has been applied to predict residualstresses induced by LsP on Ti-6Al-4V titanium alloy with laser pulse duration 30 ns and water confined ablation *** residual stress field generated by different shape laser spots was studied,and the square laser spot is shown the most suitability for avoiding stress lack phenomenon and overlapping *** residual stresses and plastically affected depth within single square spot both increased with the increase of laser intensity and laser shock ***,compared with circle and ellipse spot,the residual stress distribution in overlapping square spots is very uniform only with small overlapping *** with square spot can process advantageous residual stress field,and this technique will be used widely.

关键词： laser shock processing square spot Ti-6Al-4V residual stress

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Real-time microgrid economic dispatch based on model predictive control strategy

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Journal of Modern power systems and Clean Energy 2017年第5期5卷 787-796页

作者： Yan DU Wei PEI Naishi CHEN Xianjun GE Hao XIAO Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of sciences Beijing 100049China China Electric power Research Institute Beijing 100192China

To deal with uncertainties of renewable energy,demand and price signals in real-time microgrid operation,this paper proposes a model predictive control strategy for microgrid economic dispatch, where hourly schedule is constantly optimized according to the current system state and latest forecast information. Moreover, implicit network topology of the microgrid and corresponding power flow constraints are considered, which leads to a mixed integer nonlinear optimal power flow problem. Given the non-convexity feature of the original problem, the technique of conic programming is applied to efficiently crack the nut. simulation results from a reconstructed IEEE-33 bus system and comparisons with the routine day-ahead microgrid schedule sufficiently substantiate the effectiveness of the proposed MPC strategy and the conic programming method.

关键词： Conic programming Economic dispatch(ED) Microgrid Mixed-integer nonlinear programming(MINLP) Model predictive control(MPC) Optimal power flow(OPF)

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A decomposition model to analyze effect of sO_2 emission density of China

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Journal of Central south University 2014年第2期21卷 701-708页

作者：张平淡杜雯翠焦胜何理 school of Business Beijing Normal University school of Economics Peking University school of Environmental science and Engineering Hunan University Resources and Environmental Research Academy North China Electric Power University

A decomposition model was applied to study the resource-saving and environment-friendly effects of air pollutant emissions(taking industrial sO2 emission as an example) in *** the results,it is found that 38.93% and 61.07% are contributed to environment-friendly and resource-saving effects,respectively,by the dramatic decrease in industrial sO2 emission density(nearly 70% from 2001 to 2010).This indicates that China has achieved important progress during the 11th FYP(five-year plan) compared with the 10th FYP.A simultaneous equations model was also employed to analyze the influencing factors by using data from 30 provinces in *** results imply that the influence of environmental regulation on environment-friendly effect is not obvious during the 10th FYP but obvious during the 11th ***,the government should continue promoting the environment-friendly effect by further enhancing environmental regulation and strengthening the role of environmental management.

关键词： two-oriented society air pollution control decomposition model environmental regulation sO2 emission

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Energy separation and Explicit Dynamic Analysis of Low Temperature Impact Toughness of Transmission Tower Material Q420B

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Journal of shanghai Jiaotong university(science) 2019年第3期24卷 381-387页

作者： YU Xingxue ZHANG Yinghua ZHANG Xiaomin JIANG Yu College of Materials science and Engineering Sichuan UniversityChengdu 610065China sichuan Tongyuan Electric power Technology Co. Ltd.Chengdu 610072China

To determine the physical significance of the impact toughness parameters and accurately characterize the low temperature impact toughness of transmission tower material Q420 B,the finite element model of Charpy impact test is established on the basis of *** simulation and test results are verified,and the specimen fracture is analyzed by scanning electron *** formation and growth mechanism of the crack are dynamically *** this basis,energy separation method is used to investigate the effect of low temperature on impact *** results show that the simulation and test results are in good agreement,and the ductile-brittle transition temperature of Q420 B is about-50 ℃.The breaking process of the specimen is divided into the crack formation and *** temperature drops from 20 to-60 ℃,the crack propagation energy decreases from 51.0 to 11.9 J,the crack formation energy reduces from 39.9 to 15.8 J,and the fracture time of the material drops from 1.8 to 0.6 ms.

关键词： Q420B low temperature impact toughness simulation explicit dynamic energy separation

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Motion performance and impingement risk of total hip arthroplasty with a simulation module

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Journal of Zhejiang University-science B(Biomedicine & Biotechnology) 2013年第9期14卷 849-854页

作者： Hai ZHOU Cheng-tao WANG Wen-ting JI Xiang-sen ZENG shu FANG Dong-mei WANG Institute of Biomedical Manufacturing and Life Quality Engineering School of Mechanical and Power Energy EngineeringShanghai Jiao Tong University shanghai Fire Institute of Ministry of Public security

The present study introduced a new motion analysis method for total hip arthroplasty (THA). A motion simulation module of THA was designed and developed, which can simulate the THA’s implantation condition and motion... 详细信息

关键词： THA Motion performance and impingement risk of total hip arthroplasty with a simulation module

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A Time/space separation Based 3D Fuzzy Modeling Approach for Nonlinear spatially Distributed systems

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International Journal of Automation and computing 2018年第1期15卷 52-65页

作者： Xian-Xia Zhang Zhi-Qiang Fu shao-Yuan Li Tao Zou Bing Wang shanghai Key Laboratory of power station Automation Technology School of Mechatronics and AutomationShanghai University Institute of Automation Shanghai Jiao Tong University shenyang Institute of Automation Chinese Academy of Sciences

spatially distributed systems （sDss） are usually infinite-dimensional spatio-temporal systems with unknown nonlinearities. Therefore, to model such systems is difficult. In real applications, a low-dimensional model is required. In this paper, a time/space separation based 3D fuzzy modeling approach is proposed for unknown nonlinear sDss using input-output data measurement. The main characteristics of this approach is that time/space separation and time/space reconstruction are fused into a novel 3D fuzzy system. The modeling methodology includes two stages. The first stage is 3D fuzzy structure modeling which is based on Mamdani fuzzy rules. The consequent sets of 3D fuzzy rules consist of spatial basis functions estimated by Karhunen-Love decomposition. The antecedent sets of 3D fuzzy rules are used to construct temporal coefficients. Going through 3D fuzzy rule inference, each rule realizes time/space synthesis. The second stage is parameter identification of 3D fuzzy system using particle swarm optimization algorithm. After an operation of defuzzification, the output of the 3D fuzzy system can reconstruct the spatio-temporal dynamics of the system. The model is suitable for the prediction and control design of the sDs since it is of low-dimension and simple nonlinear structure. The simulation and experiment are presented to show the effectiveness of the proposed modeling approach.

关键词： spatially distributed system (sDs) system identification 3D fuzzy system Karhunen-Love decomposition particleswarm optimization (PsO).

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