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景程轿车可变作用力转向系统几种故障的诊断与排除
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作者 蒲永峰 《汽车技术》 北大核心 2007年第12期49-52,共4页
介绍了景程轿车可变作用力转向系统的组成和工作原理。针对该系统的常见故障,包括系统电压不正常故障、车速信号故障、控制模块故障、电磁执行器故障、警告灯常亮故障、警告灯不能点亮故障、助力作用力始终最大及助力作用力不足故障,分... 介绍了景程轿车可变作用力转向系统的组成和工作原理。针对该系统的常见故障,包括系统电压不正常故障、车速信号故障、控制模块故障、电磁执行器故障、警告灯常亮故障、警告灯不能点亮故障、助力作用力始终最大及助力作用力不足故障,分析了故障产生的原因,提出了故障诊断、排除的工艺流程。 展开更多
关键词 轿车 可变作用力转向系统 故障 诊断
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可重复使用航天器反作用力控制系统控制方法 被引量:11
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作者 房元鹏 《航空学报》 EI CAS CSCD 北大核心 2008年第B05期97-101,共5页
可重复使用航天器(RLV)再入过程初期,反作用力控制系统(RCS)是其姿态控制的主要手段,优化RCS控制方法可以降低RCS总冲需求并提高系统动态响应,以提高航天器的任务载荷和任务可靠性。以某跨大气层飞行器RCS为研究对象,给出了RCS模型和3种... 可重复使用航天器(RLV)再入过程初期,反作用力控制系统(RCS)是其姿态控制的主要手段,优化RCS控制方法可以降低RCS总冲需求并提高系统动态响应,以提高航天器的任务载荷和任务可靠性。以某跨大气层飞行器RCS为研究对象,给出了RCS模型和3种RCS控制方法,并进行仿真计算分析3种方法在完成特定飞行任务时的姿态控制效果及总冲需求。仿真结果表明:3种方法均能完成飞行器姿态控制,并各有其优缺点。本文的研究将为RLV飞行控制系统控制率设计提供有效参考。 展开更多
关键词 可重复使用航天器 作用力控制系统 控制方法 再入飞行 飞行控制
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企业技术创新过程的阶段性与风险收益区研究 被引量:2
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作者 张道宏 方志耕 胡海青 《西安理工大学学报》 CAS 2000年第4期417-422,共6页
从全新的视角将系统工程思想和寿命周期理论引入企业技术创新活动过程分析 ,指出企业在创新过程中 ,存在着高风险负 (无 )收益、低风险高收益和 (系统外 )高风险 (较 )高收益三个不同的风险收益区。运用随机系统理论 ,较深入地研究了各... 从全新的视角将系统工程思想和寿命周期理论引入企业技术创新活动过程分析 ,指出企业在创新过程中 ,存在着高风险负 (无 )收益、低风险高收益和 (系统外 )高风险 (较 )高收益三个不同的风险收益区。运用随机系统理论 ,较深入地研究了各风险收益区之间的概率转移关系 ,并将不同风险收益区的主要影响因素矢量化为风险阻力、创新引力和竞争激力三个系统作用力。在此基础上 。 展开更多
关键词 技术创新 风险收益区 转移概率 系统作用力
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基于模糊逻辑的再入RCS控制方法 被引量:2
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作者 黎科峰 宋剑爽 +1 位作者 任章 张庆振 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2008年第12期1407-1410,共4页
针对RLV(Reusable Launch Vehicle)的再入控制提出了一种基于模糊逻辑的RCS(Reaction Control System).详细分析了RCS控制特性,建立了基于效率系数以及继电特性的RCS模型,提出了一种基于Mamdani模型的模糊逻辑三通道RCS控制器,该控制器... 针对RLV(Reusable Launch Vehicle)的再入控制提出了一种基于模糊逻辑的RCS(Reaction Control System).详细分析了RCS控制特性,建立了基于效率系数以及继电特性的RCS模型,提出了一种基于Mamdani模型的模糊逻辑三通道RCS控制器,该控制器利用专家控制经验,根据姿态角及角速率的偏差,产生不同的RCS控制指令输出给三通道对飞行器进行姿态控制.通过六自由度非线性仿真,验证了该控制系统与PID(Proportional-Integral-D ifferential)控制器相比具有更好的跟踪性能,且RCS的控制输出效率也更高. 展开更多
关键词 可重复使用运载器(RLV) 作用力控制系统(RCS) 模糊逻辑 效率系数
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可重复使用航天器再入段复合控制方法研究 被引量:5
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作者 房元鹏 《飞行力学》 CSCD 北大核心 2008年第1期60-63,共4页
可重复使用航天器再入过程初期,反作用力控制系统是其姿态控制的主要手段,结合气动舵面可以减小飞行器对该系统的总冲需求,提高飞行器动态响应特性。给出了反作用力控制系统与气动舵面复合姿态控制系统的组成及三种复合控制指令分配策略... 可重复使用航天器再入过程初期,反作用力控制系统是其姿态控制的主要手段,结合气动舵面可以减小飞行器对该系统的总冲需求,提高飞行器动态响应特性。给出了反作用力控制系统与气动舵面复合姿态控制系统的组成及三种复合控制指令分配策略,并进行了仿真计算,分析了三种策略的姿态控制效果及总冲需求。仿真结果表明,三种方法均能完成飞行器姿态控制,并各有其优缺点,研究结果为航天器飞行控制系统控制律设计提供了有效参考。 展开更多
关键词 作用力控制系统 复合控制 再入飞行 飞行控制
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Sign-invariant and Explicit Solutions of Nonlinear Reaction-Diffusion Systems 被引量:1
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作者 ZHU Xiao-Ning ZHANG Shun-Li 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第6期1361-1364,共4页
Using the sign-invariant theory, we study the nonlinear reaction-diffusion systems. We also obtain some new explicit solutions to the nonlinear resulting systems.
关键词 sign-invariant theory nonlinear reaction-diffusion system explicit solutions
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Salt Effect on the Liquid-Liquid Equilibrium of (Water + Propionic Acid + Cyclohexanol) System at T=(298.2,303.2,and 308.2) K 被引量:1
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作者 Bahram Ghalami-Choobar Ali Ghanadzadeh and Shahram Kousarimehr 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2011年第4期565-569,共5页
Effects of salt and temperature on the liquid phase equilibrium of the(water + propionic acid + cyclohexanol) system were investigated.The liquid-liquid equilibrium data in the presence of KCl for various salt ionic s... Effects of salt and temperature on the liquid phase equilibrium of the(water + propionic acid + cyclohexanol) system were investigated.The liquid-liquid equilibrium data in the presence of KCl for various salt ionic strength of 0.5,1.0,1.5,2.0,and 2.5 mol·dm3 and in absence of the salt at T=(298.2,303.2,and 308.2)K were determined.The experimental results were correlated based on the Othmer-Tobias equation and Pitzer ion-interaction model.Thermodynamic properties such as distribution coefficients and activity coefficients of propionic acid in water + cyclohexanol were determined.In addition,the separation factor,S,of the chosen solvent was obtained for the investigated system. 展开更多
关键词 liquid-liquid equilibrium salt effect propionic acid distribution coefficient
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Dynamics of Non—interacting System with Long—Range Correlated Quenched Impurities
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作者 CHENYuan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第6期741-744,共4页
The theoretic renormalization group approach is applied to the study of the critical behavior of non-interacting system with long-range correlated quenched impurities, which has a power-like correlations . To two-loop... The theoretic renormalization group approach is applied to the study of the critical behavior of non-interacting system with long-range correlated quenched impurities, which has a power-like correlations . To two-loop order, the asymptotic scaling laws and the critical exponents are studied in the frame of a double expansion with ρ of order . In , it is argued that the initial slip exponent θ = 0 together with the dynamic exponent is exact in this kind of random system. 展开更多
关键词 non-interacting system critical dynamics long-range correlated quenched impurities
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Quantifying the impacts of fire aerosols on global terrestrial ecosystem productivity with the fully-coupled Earth system model CESM 被引量:2
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作者 LI Fang 《Atmospheric and Oceanic Science Letters》 CSCD 2020年第4期330-337,共8页
Fire is a global phenomenon and a major source of aerosols from the terrestrial biosphere to the atmosphere.Most previous studies quantified the effect of fire aerosols on climate and atmospheric circulation,or on the... Fire is a global phenomenon and a major source of aerosols from the terrestrial biosphere to the atmosphere.Most previous studies quantified the effect of fire aerosols on climate and atmospheric circulation,or on the regional and site-scale terrestrial ecosystem productivity.So far,only one work has quantified their global impacts on terrestrial ecosystem productivity based on offline simulations,which,however,did not consider the impacts of aerosol–cloud interactions and aerosol–climate feedbacks.This study quantitatively assesses the influence of fire aerosols on the global annual gross primary productivity(GPP)of terrestrial ecosystems using simulations with the fully coupled global Earth system model CESM1.2.Results show that fire aerosols generally decrease GPP in vegetated areas,with a global total of−1.6 Pg C yr^−1,mainly because fire aerosols cool and dry the land surface and weaken the direct photosynthetically active radiation(PAR).The exception to this is the Amazon region,which is mainly due to a fire-aerosol-induced wetter land surface and increased diffuse PAR.This study emphasizes the importance of the influence of fire aerosols on climate in quantifying global-scale fire aerosols’impacts on terrestrial ecosystem productivity. 展开更多
关键词 Fire aerosols terrestrial ecosystem gross primary productivity land–atmosphere interaction Earth system model
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Influence of wave and current on deep-sea mining transporting system 被引量:3
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作者 XU Hai-liang ZHOU Gang +1 位作者 WU Bo WU Wan-rong 《Journal of Central South University》 SCIE EI CAS 2012年第1期144-149,共6页
As a solution to the breaking of pipeline under high axial force,carbon fiber composite pipe with low density and high intensity is applied to deep-sea mining transporting system.Based on the fact that the transportin... As a solution to the breaking of pipeline under high axial force,carbon fiber composite pipe with low density and high intensity is applied to deep-sea mining transporting system.Based on the fact that the transporting pipe is under the forces of gravity,inner liquid,buoyancy as well as hydrodynamic force,geometric nonlinear finite element theory has been applied to analyzing the transporting system.Conclusions can be drawn as follows.Under the interaction of waves and currents,node forces FX and FZ acted by the transporting pipe on the mining vehicle are less than 2 kN,which indicates that waves and currents have little influence on the spatial shape of the transporting pipe and the mining vehicle movement.On the other hand,the horizontal force acting on the mining ship could be as large as 106 830 N,which has great influence on the mining system. 展开更多
关键词 carbon fiber composite pipe waves and ocean currents finite element mineral transporting system mechanical analysis
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Selective Atom-Cavity Interaction Scheme for Quantum Controlled-NOT Gate Using Four-Level Atoms in Cavity QED System 被引量:1
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作者 TANG Shi-Qing ZHANG Deng-Yu +2 位作者 XIE Li-Jun ZHAN Xiao-Gui GAO Feng 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第2期247-251,共5页
We propose a scheme for realization a quantum Controlled-NOT gate operation using two four-level atoms through a selective atom cavity interaction in cavity quantum electrodynamics system. In our protocol, the quantum... We propose a scheme for realization a quantum Controlled-NOT gate operation using two four-level atoms through a selective atom cavity interaction in cavity quantum electrodynamics system. In our protocol, the quantum information is encoded on the stable ground states of the two atoms. During the interaction between atoms and single-mode vacuum cavity-field, the atomic spontaneous emission is negligible as the large atom-cavity detuning effectively suppresses the spontaneous decay of the atoms. The influences of the dissipation and the deviation of interaction time on fidelity and corresponding success probability of the quantum Controlled-NOT gate and the experimental feasibility of our proposal are also discussed. 展开更多
关键词 controlled-NOT gate four-level atom cavity QED FIDELITY
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CFD aided investigation of single droplet coalescence 被引量:2
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作者 Felix Gebauer Mark W.Hlawitschka Hans-Jorg Bart 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第2期249-252,共4页
This article describes the development of a coalescence model using various CFD work packages,and is validated using as toluene water model system.Numerical studies were performed to describe droplet interactions in l... This article describes the development of a coalescence model using various CFD work packages,and is validated using as toluene water model system.Numerical studies were performed to describe droplet interactions in liquid–liquid test systems.Current models use adjustable parameters to describe these phenomena.The research in the past decades led to different correlations to model coalescence and breakage depending on the chemical system and the apparatus geometry.Especially the complexity of droplet coalescence requires a detailed investigation of local phenomena during the droplet interaction.Computational fluid dynamics(CFD) studies of single droplet interactions were performed and validated with experimental results to improve the understanding of the local hydrodynamics and film drainage during coalescence.The CFD simulations were performed for the interaction of two differently sized droplets at industrial relevant impact velocities.The experimental verification and validation of the numerical results were done with standardized high-speed imaging studies by using a special test cell with a pendant and a free rising droplet.An experimental based algorithm was implemented in the open source code OpenF OAM to account for the contact time and the dimple formation.The standard European Federation of Chemical Engineering(EFCE) test system toluene/water was used for the numerical studies and the experimental investigations as well.The results of the CFD simulations are in good accordance with the observed coalescence behavior in the experimental studies.In addition,a detailed description of local phenomena,like film rupture,velocity gradients,pressures and micro-droplet entrainment could be obtained. 展开更多
关键词 CFD Parameter estimation COALESCENCE Film drainage
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Q-Deformed Bosons at Quasi-classical Limit of SO(3)
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作者 ZHANG Li GAO Yi-Bo LI Yan-Min 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第3期385-390,共6页
When a boson interacts with another to form a composite system with SO(3) dynamic symmetry, it is shown that there exists the q-deformed 5osonic excitation satisfying the q-deformed Heisenberg commutation relation i... When a boson interacts with another to form a composite system with SO(3) dynamic symmetry, it is shown that there exists the q-deformed 5osonic excitation satisfying the q-deformed Heisenberg commutation relation in the quasi-classical limit that the angular momentum j for SO(3) is large, but not infinite. In second quantization this quasi-excitation is associated with the boson realization of SO(3) Lie algebra. Physically, the phenomena of q-deformed excitation can happen in many models of quantum dynamics, such as super emission from a system of many identical two-level atoms, the spin wave in Heisenberg chain, the high spin precession and the coherent output of Bose-Einstein atoms in a trap. Especially, in these models, the deformation parameter q is well defined intrinsically by a conservative quantity, such as the total atomic number and the angular momentum. 展开更多
关键词 q-deformed boson SO(3)
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Envelope Solitons Perturbed by Stochastic Noise
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作者 REN Xi-Mei ZENG Shang-You ZHAO De-Jiang TANG Yi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第11期897-900,共4页
We perform langevin dynamics simulation for envelope solitons in an FPU-β lattice,with the nearestneighborinteraction and quartic anharmonicity.We get the motion equations of our discrete system by adding noiseand da... We perform langevin dynamics simulation for envelope solitons in an FPU-β lattice,with the nearestneighborinteraction and quartic anharmonicity.We get the motion equations of our discrete system by adding noiseand damping to the set of deterministic motion equations.We define'half-time'as the time when the amplitude of theenvelope soliton decreases by half due to damping.And then the mass,center and half-time of the perturbed envelopesoliton are numerically simulated,beginning with the discrete envelope soliton at rest.Results show successfully hownoise affects behavior of the envelope soliton. 展开更多
关键词 envelope soliton noise DAMPING
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Bipartite Entanglement Dynamics in Three Qubits System with Dzyaloshinskii-Moriya Interaction
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作者 郑强 孙萍 +1 位作者 张小平 任中洲 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第9期417-420,共4页
We investigate the bipartite entanglement dynamics of the system composed by three qubits A,B,and C.There is no interaction between A and B,and that of C and B is Dzyaloshinskii-Moriya (DM) spin-orbit interaction.We f... We investigate the bipartite entanglement dynamics of the system composed by three qubits A,B,and C.There is no interaction between A and B,and that of C and B is Dzyaloshinskii-Moriya (DM) spin-orbit interaction.We find that the purity of qubits A and B and the initial state of the qubit C are the two effective parameters tocontrol the entanglement dynamics of the bipartite subsystems.This study sheds some lights on the control of quantumentanglement,which would be helpful for quantum information processing. 展开更多
关键词 entanglement sudden death entanglement lock Dzyaloshinskii-Moriya interaction
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Corona-Support for the Entirety of High Energetic Disk
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作者 Krasimira Dimitrova Yankova 《Journal of Earth Science and Engineering》 2012年第7期395-400,共6页
Based on results obtained from the study for MHD (magneto-hydrodynamics) of advective accretion disk, which are applied to real source showing typical values for CBS (close binary star-system), it will investigate... Based on results obtained from the study for MHD (magneto-hydrodynamics) of advective accretion disk, which are applied to real source showing typical values for CBS (close binary star-system), it will investigate on self-structuring in the disk under the impact of the distribution of leading parameters (density, velocity ...). The paper is considering the problem of development of the corona and will analyze the process of interaction of the plasma with the magnetic field in connection to support for the instabilities. 展开更多
关键词 Accretion disk advection MHD (magneto-hydrodynamics) instabilities.
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Tectonomicrobiology:A new paradigm for geobiological research 被引量:1
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作者 Chuanlun ZHANG Jian LIN +3 位作者 Sanzhong LI Hailiang DONG Fengping WANG Shucheng XIE 《Science China Earth Sciences》 SCIE EI CAS CSCD 2018年第4期494-498,共5页
Geomicrobiology is a sub-discipline of geobiology and emphasizes the interaction between microorganisms and their environment on Earth. There is a need to explicitly emphasize the biogeochemical processes performed by... Geomicrobiology is a sub-discipline of geobiology and emphasizes the interaction between microorganisms and their environment on Earth. There is a need to explicitly emphasize the biogeochemical processes performed by microorganisms associated with Earth's tectonic activities, especially under the framework of the modern theory of plate tectonics. Tectonomicrobiology aims to create a better synergy between microbial and active tectonic processes. This explicit synergy should also foster better communications between solid Earth scientists and life scientists in terms of holistic Earth system dynamics at both tectonic and micro-scales. 展开更多
关键词 Geobiology Geomicrobiology Tectonomicrobiology Tectonic activities Microbial evolution
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Attractive natural products with strained cyclopropane and/or cyclobutane ring systems 被引量:6
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作者 Yao-Yue Fan Xin-Hua Gao Jian-Min Yue 《Science China Chemistry》 SCIE EI CAS CSCD 2016年第9期1126-1141,共16页
The strained cyclopropane and/or cyclobutane subunits occurred in many complex natural products including terpenoids, steroids and alkaloids. Natural products with cyclopropane and/or cyclobutane motifs not only furni... The strained cyclopropane and/or cyclobutane subunits occurred in many complex natural products including terpenoids, steroids and alkaloids. Natural products with cyclopropane and/or cyclobutane motifs not only furnished fascinating structures, but also exhibited versatile biological activities, such as cytotoxic, anti-HIM antimicrobial, antiviral, and immunosuppressive effects. This review covered a large array of structurally unique natural products with strained cyclopropane and/or cyclobutane motifs and summarized their structural features, distributions, biological activities, as well as biogenetic considerations. 展开更多
关键词 natural products cyclopropane-containing cyclobutane-containing biological activity biosynthetic pathway
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Radial deformation and adhesion of carbon nanotube
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作者 WANG GenWei 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第8期1569-1573,共5页
The van der Waals(vdW) interactions of carbon nanotube(CNT)–substrate and CNT–CNT can cause strong adhesion. The adhesion can lead to radial deformation of CNTs, which is shown in both experiments and theoretical an... The van der Waals(vdW) interactions of carbon nanotube(CNT)–substrate and CNT–CNT can cause strong adhesion. The adhesion can lead to radial deformation of CNTs, which is shown in both experiments and theoretical analysis. A scaling approach is used to predict the mechanical properties, vdW adhesion, and the elastic deformation of CNTs. It is found that the indentation of CNT is proportional to R7/4 and h3/2 in nanotube–substrate system and two same CNT system. Here, R and h are the radius and the wall thickness of CNT, respectively. The indentation ratio H1/H2 for CNT–CNT is proportional to(R1/R2)3/2 and(h2/h1)3/2. 展开更多
关键词 DEFORMATION ADHESION carbon nanotube van der Waals interaction scaling law
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Cosmological evolution of quintessence with a sign-changing interaction in dark sector 被引量:3
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作者 ZHANG Ming SUN ChengYi +1 位作者 YANG ZhanYing YUE RuiHong 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第9期1805-1808,共4页
Dark energy and dark matter are only indirectly measured though their gravitational effects.It is possibie that there is some direct,non-gravitational interaction between DE and DM,which can be used to solve(or,at lea... Dark energy and dark matter are only indirectly measured though their gravitational effects.It is possibie that there is some direct,non-gravitational interaction between DE and DM,which can be used to solve(or,at least alleviate)several important theoretical problems.In the present work,by analysing the cosmological dynamical system with a dark-sector interaction which changes its sign during the cosmological evolution,we find a scaling attractor to help to alleviate the cosmic-coincidence problem.This result shows that this interaction can bring new features to the cosmology. 展开更多
关键词 cosmological evolution scaling attractor dark sector QUINTESSENCE
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