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Multi-target real-time ranging with chaotic laser radar

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Chinese Optics Letters 2008年第11期6卷 868-870页

作者：王冰洁王云才孔令琴王安帮 Physics department College of ScienceTaiyuan University of TechnologyTaiyuan 030024

We demonstrate the feasibility of multi-target real-time ranging with a chaotic laser radar. The used chaotic laser is emitted by a semiconductor laser with optical feedback. We design a proof-of-concept experiment based on the correlation detection and realize the range measurements of two targets simultaneously. The range resolution of 9 cm between two targets is achieved, which is limited by the bandwidth of the used real-time oscilloscope. A preliminary experiment of chaotic laser coherence is carried out to verify the high resolution of the chaotic lidar.

关键词： time real Multi-target real-time ranging with chaotic laser radar

Effect on Landau damping rates for a non-Maxwellian distribution function consisting of two electron populations

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Chinese Physics B 2013年第3期22卷 358-365页

作者： M.N.S.Qureshi S.Sehar H.A.Shah J.B.Cao Space science Institute Beihang University department of Physics Government College University

In many physical situations where a laser or electron beam passes through a dense plasma,hot low-density electron populations can be generated,resulting in a particle distribution function consisting of a dense cold population and a small hot *** of such low-density electron distributions can alter the wave damping rate.A kinetic model is employed to study the Landau damping of Langmuir waves when a small hot electron population is present in the dense cold electron population with non-Maxwellian distribution *** of plasma from Maxwellian distributions significantly alters the damping rates as compared to the Maxwellian *** damping is found for highly nonMaxwellian distributions as well as plasmas with a higher density and hot electron *** of weak damping is also established when the distribution contains broadened flat tops at the low energies or tends to be *** results may be applied in both experimental and space physics regimes.

关键词： Landau damping Langmuir waves two electron populations non-Maxwellian distribution function

High-pressure structures of InBi predicted by particle swarm optimization algorithm

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Chinese Physics B 2012年第2期21卷 393-397页

作者： Liu Huan-Huan Liu Yan-Hui department of Physics College of ScienceYanbian UniversityYanji 133002China

We extensively explore the high-pressure structures of InBi by using a newly developed particle swarm optimization algorithm. An orthorhombic Imma structure is discovered to be stable from 43.7 GPa to 107.9 GPa, ruling out the previously speculated cubic structure. Further increasing the pressure, we find a tetragonal P4/nmm structure which is energetically more favourable from 107.9 CPa to 200 GPa. Especially, the tetragonal P4/nmm structure is known to occur at high pressure in the structures of ZnO and MgTe. We also predict this structure to be a high-pressure structure of ZnTe. Thus the tetragonal P4/nmm structure may be a universal high-pressure structure of the Ⅱ-Ⅵ and the Ⅲ-Ⅴ compounds.

关键词： InBi structure prediction phase transitions

Influence of Annealing on Physical Properties of CdO Thin Films Prepared by SILAR Method

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Journal of Materials science & Technology 2013年第1期29卷 17-21页

作者： B.Gokul P.Matheswaran R.Sathyamoorthy PG and Research department of Physics Kongunadu Arts and Science College (Autonomous)

Cadmium oxide （CdO） thin films were prepared by successive ionic layer adsorption and reaction （SILAR） method and annealed at 250-450 ℃ for 2 h. The prepared films were characterized by X-ray diffraction （XRD）, optical spectroscopy, scanning electron microscopy （SEM） and Hall effect measurement. The XRD analysis reveals that the films were polycrystalline with cubic structure. Both crystallinity and the grain size were found to increase with increasing annealing temperature. SEM analysis shows the porous nature of the surface with spherical nanoclusters. Energy dispersive spectroscopic analysis （EDS） confirmed the presence of Cd and O elements without any additional impurities. The films exhibited maximum transmittance （82%-86%） in infra-red （IR） region. Transmittance was found to decrease with increasing annealing temperature （Eg） was in the range of 2.24-2.44 eV. Hall effect measurement shows an and the estimated band gap energy ncrease in carrier concentration and a decrease in resistivity with increasing annealing temperature. The carrier concentration （N） and resistivity （p） of about 1.26 × 1022 cm-3 and 8.71 × 10 3 Ω cm are achieved for the film annealed at 450 ℃ for 2 h.

关键词： Annealing Porous structure Hall effect Electrical resistivity

Guaranteed Rendezvous Algorithms for Cognitive Radio Networks

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China Communications 2018年第5期15卷 111-127页

作者： Li Gou Xiaohua Xu Chongqing Zhang Min Song department of Computer science Michigan Technological University department of Computer science Kennesaw State University college of Computer science & Engineering Shandong University of Science and Technology

Rendezvous is a blind process establishing a communication link on a common channel between a pair of nodes in cognitive radio networks. We propose two guaranteed rendezvous algorithms for cognitive radio networks under both single-radio and multi-radio scenarios with an asynchronous setting. For single-radio scenario, each cycle length is a prime number associated with a channel hopping *** rendezvous can be guaranteed as long as the IDs of the two nodes are different. For multi-radio scenario, we propose a cycle length and rotation based rendezvous algorithm. Each node generates a channel hopping sequence with only one cycle length. Then these radios of each nodes rotate on the generated sequence with different rotation numbers at each hopping cycle. The rendezvous between two nodes is guaranteed as long as they have different cycle lengths or the same cycle length with different number of rotations. We conduct simulations on three metrics and the results show that the proposed algorithms outperform the existing ones.

关键词： cognitive radio networks blind rendezvous channel hopping cycle length

Equation of state for pure fluids at critical temperature

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Chinese Physics B 2012年第4期21卷 378-382页

作者： S. B. Khasare department of Physics Science College Congress NagarNagpur-440010India

In this paper, we employ the concept of probability for creating a cavity with diameter d in fluid along with the perturbation and variation approach, and develop an equation of state （EOS） for a hard sphere （HS） and Lennard Jones （L J） fluids. A suitable axiomatic form for surface tension S（r） is assumed for the pure fluid, with r as a variable. The function S（r） has an arbitrary parameter rn. S（r） = A ＋ B（d/r）/[1 ＋ m（d/r）]. We use the condition in terms of radial distribution function G（λd,η） containing the self-consistent parameter λ and the condition of continuity at r = d/2 to determine A and B. A different EOS can be obtained with a suitable choice of rn and the EOS has a lower root-mean-square deviation than that of Barker-Henderson BH2 for LJ fluids.

关键词： equation of state Lenard Jones potential hard-sphere potential liquid mixture

Inverse Problem and Variation Method to Optimize Cascade Heat Exchange Network in Central Heating System

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Journal of Thermal science 2017年第6期26卷 545-551页

作者： ZHANG Yin WEI Zhiyuan ZHANG Yinping WANG Xin college of Architecture and Environment Sichuan University department of Building science Tsinghua University

Urban heating in northern China accounts for 40% of total building energy usage. In central heating systems, heat is often transferred from heat source to users by the heat network where several heat exchangers are installed at heat source, substations and terminals respectively. For given overall heating capacity and heat source tempera- tore, increasing the terminal fluid temperature is an effective way to improve the thermal performance of such cascade heat exchange network for energy saving. In this paper, the mathematical optimization model of the cas- cade heat exchange network with three-stage heat exchangers in series is established. Aim at maximizing the cold fluid temperature for given hot fluid temperature and overall heating capacity, the optimal heat exchange area dis- tribution and the medium fluids＇ flow rates arc determined through inverse problem and variation method. The preliminary results show that the heat exchange areas should be distributed equally for each heat exchanger. It al- so indicates that in order to improve the thermal performance of the whole system, more heat exchange areas should be allocated to the heat exchanger whore flow rate difference between two fluids is relatively small. This work is important for guiding the optimization design of practical cascade heating systems.

关键词： District heating Heat exchanger Thermal performance optimization Inverse problem Lagrange variation

Dynamics of Apparent Horizons in (N+2)-Dimensional Space-Times

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Chinese Physics Letters 2012年第11期29卷 23-26页

作者： S.S.Zade department of Mathematics J.B.College of ScienceWardhaIndia

We analyze the time of formation of central singularities in(N+2)-dimensional *** is shown that the time of formation of central singularity decreases with the increase in dimensions of the *** dynamics of trapped sur... 详细信息

关键词： singularity dimensions graphical

Squeeze-swapping by Bell measurement studied in terms of the entangled state representation

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Chinese Physics B 2012年第8期21卷 39-43页

作者：李学超谢传梅范洪义 department of Modern Physics University of Science and Technology of China college of Physics&Materials science Anhui University department of Material science and Engineering University of Science and Technology of China

By virtue of the entangled state representation （Hong-Yi Fan and J R Klauder 1994 Phys. Rev. A 49 704） and the two-mode squeezing operator＇s natural representation （Hong-Yi Fan and Yue Fan 1996 Phys. Rev. A 54 958） we propose the squeeze-swapping mechanism which can generate quantum entanglement and new squeezed states of continuum variables.

关键词： squeeze-swapping entangled state representation of continuum variables two-mode squeezed state Schmidt decomposition