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Communications in Theoretical Physics 2005年第3X期44卷 389-392页

作者： lu qi-Keng Institute of Mathematics Academy of Mathematics and System Sciences the Chinese Academy of Sciences Beijing 100080 China

In 1935 Dirac established the physical wave equations in the de-Sitter spaces but neither energy-momentum operators nor their conservative laws were given. In this article it is proved that in the de-Sitter group there is a subgroup group isomorphic to the Heisenberg group and the generators of this groups are the energy-momentum operators which obey a conservative law.

关键词： energy-momentum conservation Heisenberg grup de-Sitter space

Pattern formation in particle systems driven by color field

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Particuology 2008年第6期6卷 515-520页

作者： Xiaoxing Liu Huabiao qi Wei ge Jinghai Li State Key Lab of Multi-phase Complex Systems Institute of Processing Engineering Chinese Academy of Sciences PO BOX 353 Beijing 100080 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China

The structural evolution of systems with two kinds of particles driven in opposite directions, i.e., driven by a color field, is investigated by molecular dynamics simulations. Gaussian thermostat, a common treatment to restrict the thermal velocity of the particles in the systems, has been used so as to account for the dissipation of heat and allow the system to reach a steady state. It has been found that with the increase of the strength of driving force （F）, the system undergoes an obvious structural transition from an initially random mixing state to a state characterized by separate lanes and in each lane only one kind of particles exists. The analysis shows that the reason for the formation of lane structure is not only the increase of F but also the variation of particle friction coefficient. While using Gaussian thermostat the particle friction coefficient becomes a function of F. Increasing F leads to high particle friction coefficient and inevitably results in lane formation for strong enough driving force. When lifting the effect of F on friction coefficient and choosing a constant friction coefficient, our results show that for a given F there always exists a critical value of friction coefficient higher than which the system will develop into lane structure.

关键词： Color field Molecular dynamics (MD) Simulation Lane formation Driven system

Dynamics modeling and pressure control of composites tape winding system based on LQSMC

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Chinese Journal of Aeronautics 2020年第2期33卷 740-748页

作者： qi HONG Yaoyao SHI Danni lu The Key Laboratory of Contemporary Design and Integrated Manufacturing Technology Ministry of Education Northwestern Polytechnical UniversityXi’an 710072China

Pressure fluctuations during the composite fiber winding process seriously affect the produces compactness strength,fatigue resistance,stress uniformity,and resin *** accuracy of pressure control systems is affected by nonlinear disturbances,such as friction,parameter perturbation,and measurement noise.A robust control algorithm based on linear quadratic optimal control and sliding mode control(LQSMC)is proposed to overcome these *** method is based on the system state space expression and linear quadratic optimal *** state space model of the system is improved by using a Kalman filter and control input for state estimation,and a new sliding surface equation is *** ameliorated control algorithm exhibits good performance and can effectively suppress sliding mode control(SMC)*** and experimental results show that LQSMC offers high control precision,much stronger antiinterference,and robustness,which can effectively improve the positioning and tracking accuracy of a pressure control system compared with linear quadratic optimal control(LQC).The winding pressure control precision is improved by 45%to 50%.The results show that the porosity of composite fiber tape winding products decreased thanks to our method.

关键词： Composites tape winding Dynamics modeling Kalman filter LQSMC Pressure control

Effect of Glutinous Rice Flour on Mechanical Properties and Microstructure of Cement-based Materials

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Journal of Wuhan University of Technology(Materials Science) 2023年第2期38卷 394-400页

作者： FENG qi lu Bao WANG Dan Guangxi Key Lab of Road Structure and Materials Guangxi Transportation Science and Technology Group Co.LtdNanning5300007China Key Laboratory for Advanced Technology in Environment Protection of Jiangsu Province Yancheng Institute of TechnologyYancheng224051China Special Glass Key Lab of Hainan Province&State Key Laboratory of Marine Resource Utilization in South China Sea Hainan UniversityHaikou570228China

The mechanism of glutinous rice flour,a kind of natural admixture,on the hydration process,setting time,and microstructure of the Portland cement was *** experimental results show that the glutinous rice flour has an obvious setting retarding effect on cement *** optimal dosage of the glutinous rice flour is 3wt%.In this case,the initial and final setting time of the paste are delayed by 140 and185 min,*** flexural and compressive strengths of the hardened paste are increased by 0.35%and 0.07%after 56 d of *** glutinous rice flour hinders the mineral dissolution process and decreases the concentration of calcium ion at the initial stage of hydration due to the complexation effect,thereby hindering the nucleation and growth of CH and C-S-H phases and prolonging the hydration ***,C-S-H phases combine with the glutinous rice flour to contribute the bonding effect together,which compacts the microstructure of hardened cement pastes at the later hydration stage of cement ***,in-depth investigation on the utilization of glutinous rice flour as the admixture for the Portland cement is expected to be meaningful for the control of hydration exothermic rate and setting time.

关键词： glutinous rice flour cement-based materials mechanical properties setting time

Numerical simulation of stirred tanks using a hybrid immersed-boundary method

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Chinese Journal of Chemical Engineering 2016年第9期24卷 1122-1134页

作者： Shengbin Di Ji Xu qi Chang Wei ge State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China

Conventionally, multiple reference frame(MRF) method and sliding mesh(SM) method are used in the simulation of stirred tanks, however, both methods have limitations. In this study, a hybrid immersed-boundary(IB)technique is developed in a finite difference context for the numerical simulation of stirred tanks. IBs based on Lagrangian markers and solid volume fractions are used for moving and stationary boundaries, respectively, to achieve optimal efficiency and accuracy. To cope with the high computational cost in the simulation of stirred tanks, the technique is implemented on computers with hybrid architecture where central processing units(CPUs) and graphics processing units(GPUs) are used together. The accuracy and efficiency of the present technique are first demonstrated in a relatively simple case, and then the technique is applied to the simulation of turbulent flow in a Rushton stirred tank with large eddy simulation(LES). Finally the proposed methodology is coupled with discrete element method(DEM) to accomplish particle-resolved simulation of solid suspensions in small stirred tanks. It demonstrates that the proposed methodology is a promising tool in simulating turbulent flow in stirred tanks with complex geometries.

关键词： Immersed-boundary method CPU–GPU hybrid computing Stirred tank Large eddy simulation

Exponential Attractor of the 3D Derivative Ginzburg-Landau Equation

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Acta Mathematica Sinica,English Series 2008年第5期24卷 809-828页

作者： Shu Juan lu qi Shao lu Department of Mathematics & LMIB Beijing University of Aeronautics and Astronautics Beijing 100083 P. R. China

In this paper, we consider a derivative Ginzburg-Landau-type equation with periodic initial-value condition in three-dimensional spaces. Sufficient conditions for existence and uniqueness of a global solution are obtained by uniform a priori estimates of the solution. Furthermore, the existence of a global attractor and an exponential attractor with finite dimensions are proved.

关键词： derivative Ginzburg-Landau equation global attractor exponential attractor Hausdorff dimension fractal dimension

Comparison of Controlling Parameters for Near-Equatorial Tropical Cyclone Formation between Western North Pacific and North Atlantic

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Journal of Meteorological Research 2021年第4期35卷 623-634页

作者： Changhao lu Xuyang ge Melinda PENG Key Laboratory of Meteorological Disaster of Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China University of Colorado Colorado SpringColorado 80918USA

In this study,the differences in spatial distribution and controlling parameters for the formation of near-equatorial tropical cyclones(NETCs)between the western North Pacific(WNP)and the North Atlantic(NA)are *** exhibit distinctive spatial variabilities in different *** the past few decades,the majority of NETCs took place in WNP while none was observed in *** mechanism behind such a distinguishing spatial distribution difference is analyzed by using statistical *** is noted that the dynamical variables such as low-level relative vorticity and vertical wind shear(VWS)are likely the primary controlling *** with NA,larger low-level vorticity and smaller VWS appear over *** increase of vorticity attributes a lot to the turning of northeast trade *** in WNP tend to occur in the areas with VWS less than 9 m s^(-1),while the VWS in NA generally exceeds 10 m s^(-1).On the other hand,the sea surface temperature in the near-equatorial region of both of the two oceans exceeds 26.5℃and the difference of mid-level moisture is not significant;thus,thermal factors have little contribution to the distinction of NETC activities between WNP and *** oscillation(ISO)and synoptic-scale disturbances in WNP are also shown to be more favorable for NETC *** NETCs were generated in ISO active ***-scale disturbances in WNP obtain more energy from the mean flows through the barotropic energy conversion *** overall unfavorable thermal and dynamic conditions lead to the absence of NETCs in NA.

关键词： near-equatorial tropical cyclone(NETC) cyclogenesis genesis potential index(GPI)

Designing a Secure Round Function Based on Chaos

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China Communications 2020年第5期17卷 29-37页

作者： Bin lu Xin ge Fenlin Liu Zhengzhou Information Science and Technology Institute Zhengzhou 45000China Henan Key Laboratory of Network Cryptography Technology Zhengzhou 45000China

A round function based on chaos is designed combining Feistel structure’s pseudo-randomness, chaotic system’s parameter sensitivity and image data characteristics. The round function composes of two parts--data transformation based on Feistel(abbreviated as FST) and sampling output based on chaos(abbreviated as SMP). FST bases on Feistel structure and several efficient operations including bitwise xor, permutation and circulating shift. SMP is a chaos based pseudo-random sampling algorithm. It is from theoretical analysis that the round function is a pseudo-random function. The upper bounds of the average maximum differential probability and average maximum linear probability are p^2 and q^2 respectively. Finally, the good pseudo-randomness of the round function is examined with the NIST random test. The design of this round function provides an important cryptographic component for the design of chaotic image encryption algorithm.

关键词： image encryption round function chaos pseudo-random function

Investigating the co-evolution of massive black holes in dual active galactic nuclei and their host galaxies via galaxy merger simulations

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Science China(Physics,Mechanics & Astronomy) 2019年第12期62卷 96-109页

作者： Chao Yang Junqiang ge You Jun lu National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China CAS Key Laboratory for Computational Astrophysics National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China

Major galaxy mergers can trigger nuclear activities and are responsible for high-luminosity quasi-stellar objects/active galactic nuclei(QSOs/AGNs). In certain circumstances, such mergers may cause dual active galactic nuclei(dAGN) phenomenon. This study investigates dAGN triggering and evolution of massive black holes(MBHs) during the merging processes using hydrodynamic code GADgeT-2 to simulate several gas-rich major mergers at redshift z = 2 and 3, respectively. Results reveal that gas-rich major mergers can trigger significant nuclear activities after the second and third pericentric passages and the formation of dAGN with significant time duration(~10-390 Myr). During the merging processes, galactic bulge evolves with time because of the rapid star formation in each(or both) galactic centers and initial mixing of stars in galactic disks due to violent *** grow substantially due to accretion and finally merge into a bigger black hole. The growth of galactic bulges and corresponding increases of its velocity dispersions predate the growth of MBHs in the d AGN stages. The MBHs in these stages deviate below the relation between MBH mass and bulge mass(or velocity dispersion), and they revert to the relation after the final mergers due to the significant accretion that occurs mostly at a separation less than a few kpc. Then, the two MBHs merge with each other.

关键词： galaxies quasars black hole numerical simulations

An all-organic aqueous potassium dual-ion battery

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Journal of Energy Chemistry 2021年第6期30卷 28-33,I0002页

作者： Junmin ge Xianhui Yi Ling Fan Bingan lu School of Physics and Electronics State Key Laboratory of Advanced Design and Manufacturing for Vehicle BodyHunan UniversityChangsha 410082HunanChina Fujian Strait Research Institute of Industrial Graphene Technologies Quanzhou 362000FujianChina

Benefiting from the environmental friendliness of organic electrodes and the high security of aqueous electrolyte,an all-organic aqueous potassium dual-ion full battery(APDIB) was assembled with 21 M potassium bis(fluoroslufonyl)imide(KFSI) water-in-salt as the *** APDIB could deliver a reversible capacity of around 50 mAh g^(-1) at 200 mA g^(-1)(based on the weight of total active materials),a long cycle stability over 900 cycles at 500 mA g^(-1) and a high coulombic efficiency of 98.5%.The reaction mechanism of APDIB during the charge/discharge processes is verified:the FSI-could associate/disassociate with the nitrogen atom in the polytriphenylamine(PTPAn) cathode,while the K^(+) could react with C=O bonds in the 3,4,9,10-perylenetetracarboxylic diimide(PTCDI) anode *** work contributes toward the understanding the nature of water-into-salt electrolyte and successfully constructed all-organic APDIB.

关键词： All-organic electrode Potassium ion battery Dual-ion full battery Aqueous high concentration electrolyte High safety