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Self—Organized Criticality Processes in HL—1M Tokamak Plasma

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Chinese Physics Letters 2003年第1期20卷 87-89页

作者：黄渊邱孝明等 SouthwesterInstituteofPhysics PoBox432Chengdu610041

We study the dynamics of laminar time between successive bursts in anomalous particle flux measured at the HL-1M tokamak plasma edge. The results reveal that the flux fluctuations are self-similar in a narrow range of time scales and that their probability distribution function is not Gaussian. These properties are not consistent with those predicted by self-organized criticality (SOC) models as well as the running sand-pile SOC model developed by Hwa and Kardar.

关键词： distribution functions

Design and experimental research of angle self-compensation setup for BSDF measurement

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Chinese Optics Letters 2009年第5期7卷 403-406页

作者：齐超刘洪臣韦袁丽戴景民 School of Electrical Engineering and Automation Harbin Institute of Technology

When using a single reference to measure the bi-directional scattering distribution function （BSDF）, the incident zenith angle of the tested sample must be identical to that of the reference. In order to get the hemisphere space scattering characteristic on the sample surface, usually a motor drives the sample tilting, then the incident zenith angle is changed and needs to be the compensated by another motor. We mathematically deduce the expression of compensation angle when the incident zenith angle is changed by the rotation of motor. After the incident angle is compensated, the scattering zenith angle and azimuth angle are deduced too. The uncertainty of the system is 0.75%. Scattering measurements are performed on copper sample with visible light under different temperatures.

关键词： distribution functions Electric drives Motors

Measurement of bidirectional reflection distribution function on material surface

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Chinese Optics Letters 2009年第1期7卷 88-91页

作者：张伟汪洪源王治乐 Research Center for Space Optical Engineering Harbin Institute of Technology

Two automatic measurement methods of bidirectional reflection distribution function （BRDF） are presented based on absolute and relative definition. Measurement principle and scheme of the methods are analyzed. A real-time measurement device is developed, the measurement spectral range of which is from ultraviolet to near infrared with 2.4-nm wavelength resolution, and the angular range is 0° - 360° in azimuth angle and 0° - 85° in zenith angle with 0.01° angle resolution. Absolute measurements of BRDF on tinfoil and ceramic tile are performed and the test materials present apparent specular reflection characteristics. The theoretical error in the experiment is about 6.05%. The BRDF measurement results are closely related to the precision of measurement platform, the sensitivity of measurement instrument, and the stability of illuminating light source.

关键词： distribution functions Fabrics Light Light sources Lighting Probability density function Reflection Time measurement

distribution Function of Mesoscopic Hopping Conductance

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Chinese Physics Letters 2002年第11期19卷 1683-1686页

作者：何立群 LUODawei 等 DepartmentofThermalScienceandEnergyEngineering UniversityofScienceandTechnologyofChinaHefei230026 MinervaCenterandJackandPearlResnickInstituteofAdvancedTechnology Departmento DepartmentofThermalScien

We study mesoscopic hopping conductance by computer simulation distribution functions (DFs). It is found that the distributions obtainedby choosing randomly the chemical potentials (for a fixed impurity configuration), which corresponds to a typical experimental situation,coincide with those obtained when both impurity configuration and chemical potential are chosen randomly, in agreementwith the ergodicity hypothesis. The DFs in shape obtained for one-dimensional systems are found to be quite close to the predictionsof the theory by Raikh and Ruzin. For the two-dimensional case, the DFs both for a narrow system and thin film look to be similar (and close tothe one-dimensional case). The DF for the conductance of the square sample is nearly Gaussian.

关键词： distribution functions

Chemical Equilibration and Dilepton Production of Quark-Gluon Plasma at RHIC Energies

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Chinese Physics Letters 2004年第1期21卷 47-50页

作者：龙家丽贺泽君马国亮马余刚刘波 ShanghaiInstituteofNuclearResearch ChineseAcademyofSciencesPOBox800-204Shanghai201800 InstituteofHighEnergyPhysics ChineseAcademyofSciencesBeijing100039

An evolution model of the chemically equilibrating quark-gluon plasma system has been established based on the Juttner distribution function of partons. By studying the dilepton production of the system, we find that due to high initial temperature, a dominant contribution to dileptons with intermediate masses is provided by gluon density of the system as well as large gluon fusion gg → cc cross section in the intermediate mass region, quark--antiquark annihilation qq → ll and, especially, thermal charmed quarks from the gluon fusion gg → cc and quark--antiquark annihilation qq → cc.

关键词： distribution functions

Calculation method for particle mean diameter and particle size distribution function under dependent model algorithm

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Chinese Optics Letters 2007年第1期5卷 31-33页

作者：唐红孙晓刚原桂彬 Department of Automation Measurement and Control Harbin Institute of Technology

In total light scattering particle sizing technique, the relationship among Sauter mean diameter D32, mean extinction efficiency Q, and particle size distribution function is studied in order to inverse the mean diameter and particle size distribution simply. We propose a method which utilizes the mean extinction efficiency ratio at only two selected wavelengths to solve D32 and then to inverse the particle size distribution associated with Q and D32. Numerical simulation results show that the particle size distribution is inversed accurately with this method, and the number of wavelengths used is reduced to the greatest extent in the measurement range. The calculation method has the advantages of simplicity and rapidness.

关键词： Algorithms Calculations Computer simulation distribution functions Particle size

Performance analysis of relay-aided free-space optical communication system over gamma-gamma fading channels with pointing errors

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Optoelectronics Letters 2016年第4期12卷 294-298页

作者：傅慧华王平王冉冉刘晓霞郭立新杨银堂 State Key Laboratory of Integrated Service Networks School of Telecommunications Engineering Xidian University School of Physics and Optoelectronic Engineering Xidian University Key Laboratory of the Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices School of Microelectronics Xidian University

The average bit error rate(ABER) performance of a decode-and-forward(DF) based relay-assisted free-space optical(FSO) communication system over gamma-gamma distribution channels considering the pointing errors is studied. With the help of Meijer's G-function, the probability density function(PDF) and cumulative distribution function(CDF) of the aggregated channel model are derived on the basis of the best path selection scheme. The analytical ABER expression is achieved and the system performance is then investigated with the influence of pointing errors, turbulence strengths and structure parameters. Monte Carlo(MC) simulation is also provided to confirm the analytical ABER expression.

关键词： Bandwidth Bit error rate distribution functions Errors Fading channels Monte Carlo methods Probability density function Probability distributions

Average bit error rate of multi-hop parallel decode-and-forward-based FSO cooperative system with the max–min criterion under the gamma–gamma distribution

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Chinese Optics Letters 2015年第8期13卷 1-5页

作者：曹天王平郭立新杨本圣李晶杨银堂 State Key Laboratory of Integrated Service Networks School of Telecommunications EngineeringXidian University School of Physics and Optoelectronic Engineering Xidian University Key Laboratory of the Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices School of MicroelectronicsXidian University

The average bit error rate （BER） performance of a free-space optical （FOS） system based on the multi-hop parallel decode-and-forward cooperative communication method with an M-ary phase shift keying subcarrier intensity modulation is studied systematically. With the max-min criterion as the best path selection scheme, the probability density function and the cumulative distribution function of the gamma-gamma distribution random variable signal-to-noise ratio are derived. The analytical BER expression is then obtained in terms of the Gauss-Laguerre quadrature rule. Monte Carlo simulation is also provided to confirm the validity of the presented average BER model.

关键词： Bandwidth Communication channels (information theory) Cooperative communication Decoding distribution functions Intelligent systems Monte Carlo methods Optical communication Phase shift Phase shift keying Phase shifters Probability density function Probability distributions Signal to noise ratio

CalculationofEntropyProductioninSlightlyRarefiedGasFlowbySoninePolynomialExpansion

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Tsinghua Science and Technology 1996年第3期1卷 3-8页

作者：刘广均 Department of Engineering Physics Tsinghua University Beijing 100084

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关键词： Entropy Production Polynomials Fluid flow Approximation methods Eigenvalues and eigenfunctions distribution functions Author Keywords entropy kinetic theory of gases transport theory