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A Novel Onboard-gateway-based Mechanism to Improve TCP Performance in Aeronautical Satellite Networks

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Chinese Journal of Aeronautics 2007年第3期20卷 260-265页

作者： gu Ming ZHANG jun School of Electronics and lnformation Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

The IP-based networks on aircraft serve to support Intemet services via satellites. However, in aeronautical satellite hybrid networks, the TCP protocol performance often deteriorates due to improper decreases and slow recovery of the congestion window. This paper proposes a window size determination and notification mechanism, onboard-gateway-based mechanism （OGBM）, which is based on the onboard gateway in the networks on aircraft. A cross-layer approach is adopted by the onboard gateway to obtain the satellite link bandwidth information. And then, by the gateway, through changing the receiver＇s advertised window field in ACK packets, TCP sources are notified of the window size of each TCP source calculated on the ground of bandwidth delay product and flow numbers. The mechanism is able to avoid improper changes of TCP window and serve multiple users. Simulation results show that the mechanism with the fairness index close to l improves TCP performance in aeronautical satellite networks.

关键词： congestion control TCP gateway aeronautical satellite network

Volume of fluid simulation of single argon bubble dynamics in liquid steel under RH vacuum conditions

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Journal of Iron and Steel Research International 2024年第4期31卷 828-837页

作者： gu-jun Chen Sheng-ping He College of Materials Science and Engineering Yangtze Normal UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

Single argon bubble dynamics in liquid steel under Ruhrstahl-Heraeus(RH)vacuum conditions were simulated using the volume of fluid method,and the ideal gas law was used to consider bubble growth due to heat transfer and pressure *** simulation with a constant bubble density was also performed to validate the numerical method,and the predicted terminal bubble shape and velocity were found to agree with those presented in the Grace diagram and calculated by drag correlation,*** simulation results under RH conditions indicate that the terminal bubble shape and velocity cannot be *** primary bubble growth occurs within a rising distance of 0.3 m owing to heating by the high-temperature liquid steel;subsequently,the bubble continues to grow under equilibrium with the hydrostatic *** the initial diameter is 8-32 mm,the bubble diameter and rising velocity near the liquid surface are 80-200 mm and 0.5-0.8 m/s,*** bubble rises rectilinearly with an axisymmetric shape,and the shape evolution history includes an initial sphere,(dimpled)ellipsoid,and spherical cap with satellite bubbles.

关键词： Bubble dynamics Liquid steel Volume of fluid Bubble growth Bubble shape Rising velocity

Prediction of liquid circulation flow rate in RH degasser:improvement of decarburization at low atmospheric pressure

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Journal of Iron and Steel Research International 2024年第7期31卷 1661-1667页

The two-fluid model coupled with population balance model was used for simulating the gas-liquid flow in the Ruhrstahl-Heraeus(RH)*** predicted circulation flow rate was compared with that measured from a water model experiment to validate the mathematical ***,influence of snorkel immersion depth on liquid circulation flow rate was numerically investigated under an atmospheric pressure of 101 and 84 kPa,*** result indicates that the circulation flow rate of the RH degasser in the high-altitude area was severely reduced because of the decrease in atmospheric ***,increasing the snorkel immersion depth from 0.5 to 0.7 m can compensate for the decrease in atmospheric *** test result indicates that decarburization rate is significantly enhanced by increasing the snorkel immersion *** optimization,the percentage of heats with a final carbon content less than 0.002 wt.%is significantly increased from 22.0%to 96.4%.

关键词： RH degasser Two-fluid model Population balance model-Circulation flow rate Decarburization Snorkel immersion depth

Retinoic acid inducible gene-I,more than a virus sensor

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Protein & Cell 2011年第5期2卷 351-357页

作者： Feng Liu jun gu National Key Laboratory of Protein Engineering and Plant Gene Engineering LSCPeking UniversityBeijing 100871China

Retinoic acid inducible gene-I(RIG-I)is a caspase recruitment domain(CARD)containing protein that acts as an intracellular RNA receptor and senses virus *** binding to double stranded RNA(dsRNA)or 5′-triphosphate single stranded RNA(ssRNA),RIG-I transforms into an open conformation,translocates onto mitochondria,and interacts with the downstream adaptor mitochondrial antiviral signaling(MAVS)to induce the production of type Ⅰ interferon and inflammatory factors via IRF3/7 and NF-κB pathways,***,accumulating evidence suggests that RIG-I could function in non-viral systems and participate in a series of biological events,such as inflammation and inflammation related diseases,cell proliferation,apoptosis and even *** we review recent advances in antiviral study of RIG-I as well as the functions of RIG-I in other fields.

关键词： retinoic acid inducible gene-I(RIG-I) antiviral signaling inflammation innate immunity

Correlation Study on Sweetness of Amino Acid with Different Configurations and Quantum Chemical Parameters

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Chinese Journal of Structural Chemistry 2006年第5期25卷 589-593页

作者： LIjun-Ling gu jun QIU guang-Min College of Chemistry and Chemical Engineering China Universitry of Petroleum Dongying Shandong 257061 China College of Petroleum Engineering China University of Petroleum Dongying Shandong 257061 China

Quantum chemical parameters of 10 amino acids with D- and L-configurations were firstly calculated with semi-empirical AM1 method. Furthermore, the relationship between molecular structures of D-, L-amino acids and their sweetness were observed. The results show that upon different configurations of amino acids, the sweetness is relative with their formation heat, dipole moment, energy gap of frontier orbital and other parameters. The formation heats of the same amino acids possessing D- and L-configurations are different except glycine. The algebraic value of D-amino acid is generally larger than that of corresponding L-configuration with only one except of tyrosine. The dipole moment of D-amino acid is generally larger than that of corresponding L-amino acid except tyrosine and lysine. The lowest unoccupied orbital energy （ELUMO） of D-amino acid is higher than that of corresponding L-configuration except phenylalanine. △E of D-amino acid is larger than that of L-amino acid except histidine, phenylalanine and lysine. The larger gap will have advantage for its matching with frontier orbital energy of human protein acceptor, which strengthens the interaction between D-amino acid and sweet taste acceptor. Besides, the changing rules of these parameters are generally identical.

关键词： amino acid sweetness AMI semi-empirical method quantum chemical parameter

A Heat Transport Model Including the Effect of Non-Maxwellian Electron Distribution and Its Application in Laser Produced Plasma

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Chinese Physics Letters 1999年第7期16卷 520-522页

作者： ZHU Shao-ping gu Pei-jun Institute of Applied Physics and Computational Mathematics Beijing 100088

An electron heat transport model is given for studying laser-to-x-ray conversion of inertial confinement *** electron heat flux is derived based on a non-Maxwellian electron distribution,and the behavior of the heat flux is *** effect of the non-Maxwellian electron distribution on inverse bremsstrahlung heating rate and electron-ion heat transfer rate are also included in the present *** simulation results show that the effects of the non-Maxwellian electron distribution on laser absorption efficiency,laser-to-x-ray conversion efficiency and electron temperature in the coronal region are important.

关键词： Maxwell Electron distribution

PREDICTION OF VORTEX-INDUCED VIBRATION OF LONG FLEXIBLE CYLINDERS MODELED BY A COUPLED NONLINEAR OSCILLATOR:INTEGRAL TRANSFORM SOLUTION

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Journal of Hydrodynamics 2012年第6期24卷 888-898页

作者： gu Ji-jun AN Chen LEVI Carlos SU Jian Ocean Engineering Program COPPEUniversidade Federal do Rio de Janeiro Nuclear Engineering Program COPPEUniversidade Federal do Rio de Janeiro

The Generalized Integral Transform Technique （GITT） was applied to predict dynamic response of Vortex-Induced Vibration （VIV） of a long flexible cylinder. A nonlinear wake oscillator model was used to represent the cross-flow force acting on the cylinder, leading to a coupled system of second-order Partial Differential Equations （PDEs） in temporal variable. The GITT approach was used to transform the system of PDEs to a system of Ordinary Differential Equations （ODEs）, which was numerically solved by using the Adams-Moulton and Gear method （DIVPAG） developed by the International Mathematics and Statistics Library （IMSL）. Numerical results were presented for comparison to those given by the finite difference method and experimental results, allowing a critical evaluation of the technique performance. The influence of variation of mean axial tension induced by elongation of flexible cylinder was evaluated, which was shown to be not negligible in numerical simulation of VIV of a long flexible cylinder.

关键词： Vortex-Induced Vibration (VIV) nonlinear wake oscillator flexible cylinder integral transform

Dissolved methane in anaerobic effluent:Emission or recovery?

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Frontiers of Environmental Science & Engineering 2022年第4期16卷 161-163页

作者： Xiaoyuan Zhang jun gu Shujuan Meng Yu Liu Advanced Environmental Biotechnology Centre Nanyang Environment&Water Research InstituteNanyang Technological UniversitySingapore 637141Singapore Department of Environmental Science and Engineering School of Energy and EnvironmentSoutheast UniversityNanjing 210096China School of Space and Environment Beihang UniversityBeijing 100191China School of Civil and Environmental Engineering Nanyang Technological UniversitySingapore 639798Singapore

Various anaerobic processes have been explored for the energy-efficient treatment of municipal ***,dissolved methane in anaerobic effluent appears to be a barrier towards the energy and carbon neutrality of wastewater *** several dissolved methane recovery methods have been developed,their engineering feasibility and economic viability have not yet been assessed in a holistic *** this perspective,we thus intend to offer additional insights into the cost-benefit of dissolved methane recovery against its emission.

关键词： Anaerobic treatment Municipal wastewater Dissolved methane Methane recovery Carbon emission

APPLICATION OF WEIGHTED NONOSCILLATORY AND NON-FREE-PARAMETER DISSIPATION DIFFERENCE SCHEME IN CALCULATING THE FLOW OF VIBRATING FLAT CASCADE

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Chinese Journal of Mechanical Engineering 2007年第6期20卷 69-73页

作者： XIAO jun gu Chuangang SHU Xinwei Key Laboratory for Power Machinery and Engineering Ministry of Education Shanghai Jiaotong University Shanghai 200030 China

A dual-time method is introduced to calculate the unsteady flow in a certain vibrating flat cascade. An implicit lower-upper symmetric-gauss-seidel scheme（LU-SGS） is applied for time stepping in pseudo time domains, and the convection items are discretized with the spatial three-order weighted non-oscillatory and non-free-parameter dissipation difference （WNND） scheme. The turbulence model adopts q-co low-Reynolds-number model. The frequency specmuns of lift coefficients and the unsteady pressure-difference coefficients at different spanwise heights as well as the entropy contours at blade tips on different vibrating instants, are obtained. By the analysis of frequency specmuns of lift coefficients at three spanwise heights, it is considered that there exist obvious non-linear perturbations in the flow induced by the vibrating, and the perturbation frequencies are higher than the basic frequency. The entropy contours at blade tips at different times display an intensively unsteady attribute of the flow under large amplitudes.

关键词： Vibrating cascade Weighted non-oscillatory and non-free-parameter dissipation difference scheme Frequency spectrum of lift coefficient Unsteady pressure-difference coefficient