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Ideal Strengths and Bonding Properties of PuO_(2)under Tension

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Chinese Physics Letters 2011年第4期28卷 178-181页

作者： WANG Bao-tian ZHANG ping Institute of Theoretical Physics and the Department of Physics Shanxi UniversityTaiyuan 030006 LCP Institute of Applied Physics and Computational MathematicsBeijing 100088

We perform a first-principles computational tensile test on PuO_(2)based on density-functional theory within a local density approximation(LDA)+U formalism to investigate its structural,mechanical,magnetic and intrinsic bonding properties in four representative directions:[001],[100],[110]and[111].The stress-strain relations show that the ideal tensile strengths in the four directions are 81.2,80.5,28.3 and 16.8 GPa at strains of 0.36,0.36,0.22 and 0.18,***[001]and[100]directions are prominently stronger than the other two directions since more Pu-0 bonds participate in the pulling *** charge and density of state analysis along the[001]direction,we find that the strong mixed ioni%ovalent character of the Pu-0 bond is weakened by tensile strain and PuO_(2)will exhibit an insulator-to-metal transition after tensile stresses exceeding about 79 GPa.

关键词： process strain directions

The Relationship between Melt Season Sea Ice over the Bering Sea and Summer Precipitation over Mid-Latitude East Asia

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Advances in Atmospheric Sciences 2021年第6期38卷 918-930页

作者： Yurun tian Yongqi GAO dong GUO Nansen-Zhu International Research Centre Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Nansen Environmental and Remote Sensing Centre/Bjerknes Centre for Climate Research Bergen N-5006Norway Climate Change Research Centre Chinese Academy of SciencesBeijing100029China

Independent datasets consistently indicate a significant correlation between the sea ice variability in the Bering Sea during melt season and the summer rainfall variability in the Lake Baikal area and Northeastern *** this study,four sea ice datasets(HadISST1,HadISST2.2,ERA-Interim and NOAA/NSIDC)and two global precipitation datasets(CRU V4.01 and GPCP V2.3)are used to investigate co-variations between melt season(March−April−May−June,MAMJ)Bering Sea ice cover(BSIC)and summer(June−July−August,JJA)East Asian *** datasets demonstrate a significant correlation between the MAMJ BSIC and the JJA rainfall in Lake Baikal−Northeastern China(Baikal−NEC).Based on the reanalysis datasets and the numerical sensitivity experiments performed in this study using Community Atmospheric Model version 5(CAM5),a mechanism to understand how the MAMJ BSIC influences the JJA Baikal−NEC rainfall is *** MAMJ BSIC triggers a wave train and causes a positive sea level pressure(SLP)anomaly over the North Atlantic during *** high SLP anomaly,associated with an anti-cyclonic wind stress circulation anomaly,favors the appearance of sea surface temperature(SST)anomalies in a zonal dipole-pattern in the North Atlantic during *** dipole SST anomaly drives a zonally orientated wave train,which causes a high anomaly geopotential height at 500 hPa over the Sea of *** a result,the mean East Asian trough moves westward and a low geopotential height anomaly occurs over Baikal−*** prevailing regional low pressure anomaly together with enhanced moisture transport from the western North Pacific and convergence over Baikal−NEC,positively influences the increased rainfall in summer.

关键词： Bering Sea ice North Atlantic SST East Asian summer precipitation wave train

Modulation instability,rogue waves and conservation laws in higher-order nonlinear Schrodinger equation

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Communications in Theoretical Physics 2021年第2期73卷 1-10页

作者： Min-Jie dong Li-Xin tian School of Mathematical Sciences Nanjing Normal UniversityNanjingJiangsu 210023China Nonlinear Scientific Research Center Jiangsu UniversityZhenjiangJiangsu 212013China

In this paper,the modulation instability(MI),rogue waves(RWs)and conseryation laws of the coupled higher-order nonlinear Schrodinger equation are *** to MI and the 2×2 Lax pair,Darboux-dressing transformation with an asymptotic expansion method,the existence and properties of the one-,second-,and third-order RWs for the higher-order nonlinear Schrodinger equation are *** addition,the main characteristics of these solutions are discussed through some graphics,which are draw widespread attention in a variety of complex systems such as optics,Bose-Einstein condensates,capillary fow,superfluidity,fluid dynamics,and *** addition,infinitely-many conservation laws are established.

关键词： higher-order nonlinear Schrodinger equation modulation instability rogue waves conservation laws

Transformation mechanism of nutrient elements in the process of biochar preparation for returning biochar to soil

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Chinese Journal of Chemical Engineering 2017年第4期25卷 477-486页

作者： Shuangshuang tian Zhongxin Tan Alfreda Kasiuliene ping Ai College of Resources and Environment HuazhongAgricultural UniversityWuhan 430070China Waste Science and Technology Department of CivilEnvironmental and Natural Resources EngineeringLulea University of TechnologySE-97187 LuleaSweden College of Engineering Huazhong Agricultural UniversityWuhan 430070China

Returning biochar to soil is a heavily researched topic because biochar functions well for soil improvement. There is a significant loss of nutrients, which occurs during biochar preparation before biochar is returned to soil,thereby seriously undermining biochar＇s efficacy. Therefore, the transformation mechanisms of biochar p H,mass, nutrients and metals during pyrolysis under different atmospheres and temperatures were studied such that the best method for biochar preparation could be developed. Several conclusions can be reached：（1） a CO2 atmosphere is better than a N2 atmosphere for biochar preparation, although preparation in a CO2 atmosphere is not a common practice for biochar producers;（2） 350 ℃is the best temperature for biochar preparation because the amount of nutrient loss is notably low based on the premise of straw transferred into biochar; and（3） transforming mechanisms of pH, N, P and K are also involved in the biochar preparation process.

关键词： nutrient Transformation pyrolysis seriously alkaline premise kinetics notably thereby volatile

Ideal optomechanically induced transparency generation in a cavity optoelectromechanical system

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Chinese Physics B 2021年第10期30卷 364-370页

作者： Jing Wang Xue-dong tian College of Physics Tonghua Normal UniversityTonghua 134000China College of Physics Science and Technology Guangxi Normal UniversityGuilin 541004China

The ideal optomechanically induced transparency effects of an output probe field are investigated in a cavity optoelectromechanical system,which is composed of an optical cavity,a charged mechanical resonator,and a charged *** the charged mechanical resonator damping rate is nonzero,the ideal optomechanically induced transparency can still appear due to the non-rotating wave approximation effect in the *** location of optomechanically induced transparency dip can be controlled via the Coulomb coupling *** addition,we find that both the transparency window width and the maximum dispersion curve slope are closely related to the optical cavity decay rate.

关键词： ideal optomechanically induced transparency cavity optoelectromechanical system transparency window width

Anion-site-modulated thermoelectric properties in Ge2Sb2Te5-based compounds

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Rare Metals 2020年第10期39卷 1127-1133页

作者： ping Hu tian-Ran Wei Shao-Ji Huang Xu-Gui Xia Peng-Fei Qiu Jiong Yang Li-dong Chen Xun Shi State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China Materials Genome Institute Shanghai UniversityShanghai 200444China

The amalgamation of multi-subjects often elicits novel materials,new concepts and unexpected ***,Ge2 Sb2 Te5,as the most established phasechange material,has been found to exhibit decent thermoelectric performance in its stable,hexagonal *** challenge for higher figure of merit(zT) values lies in reducing the hole carrier concentration and enhancing the Seebeck coefficient,which,however,can be hardly realized by conventional *** in this work,we report that the electrical properties of Ge2 Sb2 Te5 can be readily optimized by anion-site ***,Se/S substitution for Te induces stronger and more ionic bonding,lowering the hole ***,an increase in electronic density of state is introduced by Se substitution,contributing to a large increase in Seebeck *** with the reduced thermal conductivity,maximum zT values above 0.7 at 800 K have been achieved in Se/S-alloyed materials,which is ~30% higher than that in the pristine Ge2Sb2 Te5.

关键词： Thermoelectric Ge2Sb2Te5 Anion-site modulation Chemical bond Electronic density of states

Sunflower response to potassium fertilization and nutrient requirement estimation

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Journal of Integrative Agriculture 2018年第12期17卷 2802-2812页

作者： LI Shu-tian DUAN Yu GUO tian-wen ZHANG ping-liang HE ping Kaushik Majumdar Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural SciencesBeijing 100081P.R.China International Plant Nutrition Institute Beijing Office Beijing 100081P.R.China Institute of Resources Environment and Detection Technology Inner Mongolia Academy of Agricultural and Animal Husbandry SciencesHohhot 010031P.R.China Dryland Agriculture Institute Gansu Academy of Agricultural SciencesLanzhou 730070P.R.China International Plant Nutrition Institute (IPNI) Gurgaon 122001India

Field experiments were conducted in oil and edible sunflower to study the effects of potassium(K) fertilization on achene yield and quality, and to estimate the nutrient internal efficiency(IE) and nutrient requirement in sunflower production. All trials in edible sunflower and 75% trials in oil sunflower showed positive yield responses to K fertilization. Compared with control without K fertilization, the application of K increased achene yield by an average of 406 kg ha–1for oil sunflower and 294 kg ha–1for edible sunflower. K application also increased 1 000-achene weight and kernel rate of both oil and edible sunflower. K fertilization improved the contents of oil, oleic acid, linoleic acid and linolenic acid in achenes of oil sunflower, and increased contents of oil, total unsaturated fatty acid and protein in achenes of edible sunflower. The average agronomic efficiency of K fertilizer was 4.0 for oil sunflower and 3.0 kg achene kg–1K2O for edible sunflower. The average IE of N, P and K under balanced NPK fertilization was 22.9, 82.8, and 9.9 kg kg–1for oil sunflower, and 27.3, 138.9, and 14.3 kg kg–1for edible sunflower. These values were equivalent to 45.5, 14.1, and 108.1 kg, and 39.0, 8.0, and 71.7 kg of N, P and K, respectively, in above-ground dry matter required for production per ton of achenes. The average harvest index of N, P and K was 0.47, 0.56 and 0.05 kg kg–1in oil sunflower, and 0.58, 0.58 and 0.14 kg kg–1in edible sunflower.

关键词： sunflower potassium yield response K use efficiency

Robust Platoon Control of Mixed Autonomous and Human-Driven Vehicles for Obstacle Collision Avoidance:A Cooperative Sensing-Based Adaptive Model Predictive Control Approach

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Engineering 2024年第11期42卷 244-266页

作者： Daxin tian Jianshan Zhou Xu Han ping Lang State Key Laboratory of Intelligent Transportation Systems Beihang UniversityBeijing 100191China Beijing Key Laboratory for Cooperative Vehicle Infrastructure Systems&Safety Control Beihang UniversityBeijing 100191China School of Transportation Science and Engineering Beihang UniversityBeijing 100191China Zhongguancun Laboratory Beijing 100094China

Obstacle detection and platoon control for mixed traffic flows,comprising human-driven vehicles(HDVs)and connected and autonomous vehicles(CAVs),face challenges from uncertain disturbances,such as sensor faults,inaccurate driver operations,and mismatched model ***,misleading sensing information or malicious attacks in vehicular wireless networks can jeopardize CAVs’perception and platoon *** this paper,we develop a two-dimensional robust control method for a mixed platoon,including a single leading CAV and multiple following HDVs that incorpo-rate robust information sensing and platoon *** effectively detect and locate unknown obstacles ahead of the leading CAV,we propose a cooperative vehicle-infrastructure sensing scheme and integrate it with an adaptive model predictive control scheme for the leading *** sensing scheme fuses information from multiple nodes while suppressing malicious data from attackers to enhance robustness and attack resilience in a distributed and adaptive ***,we propose a distributed car-following control scheme with robustness to guarantee the following HDVs,considering uncertain *** also provide theoretical proof of the string stability under this control ***,extensive simulations are conducted to validate our *** simulation results demonstrate that our method can effectively filter out misleading sensing information from malicious attackers,significantly reduce the mean-square deviation in obstacle sensing,and approach the theoretical error lower ***,the proposed control method successfully achieves obstacle avoidance for the mixed platoon while ensuring stability and robustness in the face of external attacks and uncertain disturbances.

关键词： Connected autonomous vehicle Mixed vehicle platoon Obstacle collision avoidance Cooperative sensing Adaptive model predictive control

Stability analysis of multiple-lattice self-anticipative density integration effect based on lattice hydrodynamic model in V2V environment

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Chinese Physics B 2021年第12期30卷 167-174页

作者： Geng Zhang Da-dong tian College of Computer and Information Science Southwest UniversityChongqing 400715China College of Information Science and Engineering Shandong Agricultural UniversityTai’an 271018China

Under the environment of vehicle-to-vehicle(V2V)communication,the traffic information on a large scale can be obtained and used to coordinate the operation of road traffic *** this paper,a new traffic lattice hydrodynamic model is proposed which considers the influence of multiple-lattice self-anticipative density integration on traffic flow in the V2V *** theoretical analysis,the linear stability condition of the new model is derived and the stable condition can be enhanced when more-preceding-lattice self-anticipative density integration effect is taken into *** property of the unstable traffic density wave in the unstable region is also studied according to the nonlinear *** is shown that the unstable traffic density wave can be described by solving the modified Korteweg-de-Vries(mKdV)***,the simulation results demonstrate the validity of the theoretical *** theoretical analysis and numerical simulations demonstrate that multiple-lattice self-anticipative density integration effect can enhance the stability of traffic flow system in the V2V environment.

关键词： lattice hydrodynamic model traffic stability self-anticipative density integration mKdV equation