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Centrality and energy dependence of rapidity correlation patterns in relativistic heavy ion collisions

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Chinese Physics C 2011年第3期35卷 259-263页

作者：乐天许明梅吴元芳 Institute of Particle Physics Huazhong Normal University Key Lab of Quark and Lepton Physics (Huazhong Normal University) Ministry of Education

The centrality and energy dependence of rapidity correlation patterns are studied in Au＋Au collisions by using AMPT with string melting, RQMD and UrQMD models. The behaviors of the shortrange correlation （SRC） and the long-range correlation （LRC） are presented clearly by two spatial-position dependent correlation patterns. For centrality dependence, UrQMD and RQMD give similar results as those in AMPT, i.e., in most central collisions, the correlation structure is flatter and the correlation range is larger, which indicates a long range rapidity correlation. A long range rapidity correlation showing up in RQMD and UrQMD implies that parton interaction is not the only source of long range rapidity correlations. For energy dependence, AMPT with string melting and RQMD show quite different results. The correlation patterns in RQMD at low collision energies and those in AMPT at high collision energies have similar structures, i.e. a convex curve, while the correlation patterns in RQMD at high collision energies and those in AMPT at low collision energies show flat structures, having no position dependence. Long range rapidity correlation presents itself at high energy and disappears at low energy in RQMD, which also indicates that long range rapidity correlations may come from some trivial effects, rather than the parton interactions.

关键词： correlation patterns rapidity short-range correlation long-range correlation

Centrality,azimuthal and rapidity dependence of two-particle transverse-momentum correlation in relativistic heavy ion collisions

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Chinese Physics C 2009年第4期33卷 281-284页

作者：黄燕萍吴元芳 Institute of High Energy Physics CAS Institute of Particle Physics Huazhong Normal University

The centrality, azimuthal and rapidity dependence of two-particle transverse-momentum correlations are studied for Au-Au collision at 200 GeV using RQMD （relativistic quantum molecular dynamics） with and without final hadron re-scattering models. The influences of the re-scattering effects on the measured correlations are discussed. The results are compared with those from current heavy ion experiments.

关键词： centrality azimuthal rapidity transverse-momentum correlation.

The rapidity of phase difference calculation algorithm of Coriolis Mass Flowmeter and its effect on measurement

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The rapidity of phase difference calculation algorithm of Co...

Effect of Dynamic Pressure Feedback Orifice on Stability of Cartridge-Type Hydraulic Pilot-Operated Relief Valve

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作者： Wei Wu Lijun Sun Haiming Wang Shuai Dong Xin Shao Tianjin Key Laboratory of Process Measurement and Control School of Electrical and Information Engineer Tianjin University School of Intelligent Manufacturing Tianjin Sino-German University of Applied Sciences

Coriolis Mass Flowmeter(CMF) is widely used in industrial and life *** the complexity of working conditions increase,the signal processing algorithm of CMF requires higher *** this paper,the performance of Complex Coefficient Filter(CCF),Quadrature Demodulation(QD) and Hilbert algorithms is compared in terms of the rapidity of the algorithm,taking into account the anti-noise ability and *** pulsating flow signal simulation,the tracking ability of the three algorithms for abrupt signals is *** improved two-phase flow random walk model simulation,the fast solving performance and anti-noise ability of the three algorithms are compared,and the execution time of the algorithms is *** simulation results show that the capabilities of CCF and QD are better than *** of pulsating flow and gas-liquid two-phase flow are designed to verify the performance of CCF and QD *** experimental results show that the measurement accuracy and repeatability of CCF algorithm are better than that of QD in pulsating *** gas-liquid two-phase flow,the measurement error of CCF algorithm is smaller than that of QD,and the repeatability is better than that of QD except for some *** the liquid flow rate is constant,with the increase of gas content,the measurement error of the CCF algorithm is smaller than that of *** the flow pattern changes,the CCF algorithm can track the signal *** the speed of the algorithm increase,the ability of tracking changing signals is stronger,which is benefit for improving the accuracy of measuring gas-liquid two-phase flow and pulsating flow.

关键词： Coriolis mass flowmeter Phase difference algorithm rapidity Gas-liquid two-phase flow Pulsating flow

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Chinese Journal of Mechanical Engineering 2023年第4期36卷 227-241页

作者： Yaobao Yin Dong Wang Junyong Fu Hong-chao Jian School of Mechanical Engineering Tongji UniversityShanghai 201804China Shanghai Aerospace Control Technology Institute Shanghai 201109China China North Vehicle research institute Beijing 100072China

Current research on pilot-operated relief valve stability is primarily conducted from the perspective of system dynamics or stability criteria,and most of the existing conclusions focus on the spool shape,damping hole size,and pulsation frequency of the ***,the essential factors pertaining to the unstable vibration of relief valves remain *** this study,the dynamic behavior of a pilot-operated relief valve is investigated using the frequency-domain *** result suggests that the dynamic pressure feedback orifice is vital to the dynamic characteristics of the valve.A large orifice has a low flow *** this case,the fluid in the main spring chamber flows freely,which is not conducive to the stability of the relief ***,a small orifice may create significant flow resistance,thus restricting fluid *** this case,the oil inside the main valve spring chamber is equivalent to a high-stiffness liquid *** main mass-spring vibration system has a natural frequency that differs significantly from the operating frequency of the relief valve,which is conducive to the stability of the relief *** agreement is obtained between the theoretical analysis and *** results indicate that designing a dynamic pressure feedback orifice of an appropriate size is beneficial to improving the stability of hydraulic pilot-operated relief *** addition,the dynamic pressure feedback orifice reduces the response speed of the relief *** study comprehensively considers the stability,rapidity,and immunity of relief valves and expands current investigations into the dynamic characteristics of relief valves from the perspective of classical control theory,thus revealing the importance of different parameters.

关键词： Pilot-operated relief valve Dynamic pressure feedback orifice Stability rapidity Immunity

Study on the method of mini-jet identification in relativistic heavy ion collisions

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Chinese Physics C 2011年第9期35卷 833-837页

作者：李德胜田凤革陈刚 School of Mathematics and Physics China University of Geosciences Key Laboratory of Quark & Lepton Physics(Huazhong Normal University) Ministry of Education

In this paper a set of methods identifying minijet from final state particles in the relativistic heavy ion collision events is established and the parameter dependence has been investigated in Au＋Au collisions at √s=200 GeV using a multiphase transport model （AMPT）. It is found that the number of minijets reduces with the increasing of collision parameter and raises with the increasing of c.m energy. Furthermore, we analyze the rapidity and momentum distribution inside minijets identified using this method.

关键词： high energy collisions mini-jet identification transverse momentum rapidity

Emission of Protons in Inelastic Nucleus-Nucleus Collisions at High Energy

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Chinese journal of nuclear physics 1995年第4期17卷 292-297页

作者： Liu, Fuhu Shanxi Teachers Univ Linfen China

Based on the participant-spectator model and the analysis of particle producing proce-ss, the rapidity distribution and the noninvariant center-of-mass energy spectrum of final pro-tons produced in inelastic nucleus-n... 详细信息

关键词： Nucleus-nucleus collisions Final protons rapidity distribution Noninvariant c.m. energy spectrum

Modular zonal fluid sampling and pressure testing technology for production well

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Petroleum Exploration and Development 2022年第2期49卷 438-447页

作者： XU Jianguo YANG Qinghai YI Peng HOU Ze JIA Weite FU Tao ZHANG Zonglin YUE Qingfeng Jilin Oilfield Oil&Gas Engineering Research Institute Songyuan 138000China PetroChina Research Institute of Petroleum Exploration&Development Beijing 100083China Jilin Oilfield Xinmu Production Plant Songyuan 138000China Daqing Oilfield Production Engineering Research Institute Daqing 163453China

To accurately obtain development dynamic data such as zonal pressure and fluid parameters of each oil layer in the late development stage of a high water-cut old oilfield, a modular zonal sampling and testing technology with the characteristics of modularization, full electronic control and rapidity was proposed and developed. Lab testing and on-site testing was carried out. The modular zonal sampling and testing system is composed of 10 functional modules, namely ground control system, downhole power supply module, drainage pump, electronically controlled anchor, electronically controlled packer, electronically controlled sampler, magnetic positioning sub, terminal sub, adapter cable, and quick connector. Indoor tests have confirmed that the performance parameters of each module meet the design requirements. The downhole function modules of the system can withstand pressures up to 35 MPa and temperatures up to 85 ℃. The rubber cylinder of the electronically controlled packer can withstand a pressure difference of more than 10 MPa. The electronically controlled anchor has an anchoring force of greater than 6.9 t, and can be forcibly detached in the event of an accident. The discharge pump has a displacement of 0.8 m;/d and a head of 500 m. The electronically controlled sampler can meet the requirement of taking 500 mL of sample in each of the 3 chambers. Field tests in Jilin Oilfield show that the system can realize rapid isolation and self-check of isolation of a certain production interval downhole, as well as layer-by layer pressure build-up test. The drainage pump can be used to discharge the mixed liquid between the upper and lower packers and near the wellbore to obtain real fluid samples of the tested formation interval. The data obtained give us better understanding on the pay zones in old oilfields, and provide important basis for development plan adjustment, reservoir stimulation, and EOR measures.

关键词： zonal sampling zonal testing modularization full electronic control rapidity enhanced oil recovery fluid sampling pressure testing

Interaction of ²⁸Si with Emulsion Nuclei at 4.5 AGeV/c in View of Thermo-Statistical Approach

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Journal of Applied Mathematics and Physics 2023年第3期11卷 629-638页

作者： Mohamed Tawfik Ghoneim Zeinab Abdel-Halim Mohamed Tarek Hussein Faculty of Science Cairo University Cairo Egypt

In this work, we study some changes of nuclear matter in the interactions of 28Si with emulsion nuclei at 4.5 AGeV/c. From the experimental quantities investigated using Tsallis’ statistics, we deduced the temperature, entropy density and non-equilibrium factor of the nuclear medium. These obtained parameters were used to reveal variations in the nuclear matter at the stated interaction energy. The results that came up from this study were compared with their corresponding results obtained from other heavy ion collision experiments at wide energy range.

关键词： Silicon Nuclear Emulsion rapidity Heavy Ions Collision

Formulae for Energy and Momentum of Relativistic Particle Regular at Zero-Mass State

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Journal of Modern Physics 2011年第8期2卷 849-856页

作者： Robert M Yamaleev 不详

In this paper we substantiate a necessity of introduction of a concept the counterpart of rapidity into the framework of relativistic physics. It is shown, formulae for energy and momentum defined via counterpart of rapidity are regular near the zero-mass and speed of light states. The representation for the energy-momentum is realized as a mapping from the massless-state onto the massive one which looks like as a 'q'-deformation. Quantization of the energy, momentum and the velocity near the light-speed is presaged. An analogue between the relativistic dynamics and the statistical thermodynamics of a micro-canonical ensemble is brought to light.

关键词： Relativistic Dynamics Complex Algebra rapidity Energy-Momentum Background Energy Statistical Thermodynamics.