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Preliminary Results on the First Optical Molasses of Cs Atoms in China

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Chinese Physics Letters 1998年第6期15卷 413-415页

作者： HOU Ji-dong LI Yi-min YANG Dong-hai WANG Yi-qiu department of electronics Peking UniversityBeijing 100871

Based on an improved optical system,which consists of six laser diodes with two injection locking stages and control set-ups of the intensity and frequency of the laser,we have achieved the first optical molasses in *** time-of-flight(TOF)signal of the cloud of Cs atoms has been obtained,and an analytical-formula for measuring the temperature of the atomic cloud from its TOF signal is *** lowest temperature of the cloud of Cs atoms is measured to be 10μK.

关键词： optical laser signal

A New Pumping-Probing Scheme for the Optically Pumped Cesium Beam Frequency Standard

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Chinese Physics Letters 2001年第1期18卷 16-17页

作者： CHEN Jing-Biao ZHU Cheng-Jin WANGFeng-Zhi YANG Dong-Hai WANG Yi-Qiu department of electronics Peking UniversityBeijing 100871

A new pumping-probing scheme for the optically pumped cesium beam frequency standard has been experimentally tested in our *** stability of the optically pumped cesium beam frequency standard was measured by comparing its 10 MHz output with an HP5071A commercial cesium atomic *** result shows that the frequency stability for the 1 s and 30000s sample times are 1.2×10^(-11) and 3.7×10^(-13),*** was proved that the new pumping scheme works well.

关键词： pumping pumped Optically

A Scheme for Realizing the Continuous Wave Atom Laser

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Chinese Physics Letters 2000年第11期17卷 784-786页

作者： ZHOU Xian-Ji WANG Yi-Qiu YANG Dong-Hai department of electronics Peking UniversityBeijing 100871

We propose a scheme for realizing the long-term continuous output of an atom *** this scheme the cold atoms in several subsidiary Bose-Einstein condensates(BEC)will be coupled one by one in turn into one main BEC which serves for the continuous output of a coherent atomic *** discuss the process of the phase unification of the newly entered BEC atoms with the remaining atoms in the main BEC *** ideal dynamical equilibrium can be established when the transition rate of the uncondensed atoms transforming into the condensate and the decay rate of coupling output satisfy some *** coupling method from the subsidiary BEC to the main BEC and the time rates of all different processes are considered.

关键词： BEC coupling satisfy

Effect of magnetic field orientation on fluidized beds of magnetic particles:Theory and experiment

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Particuology 2014年第1期12卷 54-63页

作者： Miguel ángel Sánchez Quintanilla Manuel Jesús Espin José Manuel Valverde department of electronics and Electromagnetism University of Seville department of Applied PhysicsⅡ University of Seville

Geldart-A fluidized beds of fine particles experience a jamming transition between a fluid-like state and a solid-like state at a certain superficial gas velocity, that depends on the relative strength of interparticle attractive forces with respect to particle weight, lnterparticle forces provide the bed with a certain tensile strength in the jammed state. In the work presented here we analyze the behavior of a fluidized bed of magnetic particles subjected to an externally applied magnetic field, which contributes to enhance interparticle forces. The importance of the magnetic contribution to interparticle forces is measured by the changes in the tensile strength and the superficial gas velocity at the jamming transition. The link of the field orientation with the microstructure of the bed is discussed,

关键词： Magneto-fluidization Jamming transition Fluidization Fine powders Cohesion Magnetization

Computer-generated holograms for 3D display(Invited Paper)

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Chinese Optics Letters 2009年第12期7卷 1079-1082页

作者： Hiroshi Yoshikawa Takeshi Yamaguchi department of electronics and Computer Science Nihon University

We have been studying various types of computer-generated holograms for three-dimensional （3D） displays both for a real-time holographic video display and a hard copy, or a printed hologram. For the hard copy output, we have developed a direct fringe printer, which is achieved to print over 100 gigapixels computer-generated hologram with 0.44μm pitch. In this paper, we introduce our recent progresses on the rainbow hologram, the cylindrical holograms, and the disk hologram for 3D display.

关键词： Computer-generated holograms for 3D display Figure

Surface effect of nanocrystals doped with rare-earth ions enriched on surface and its application in upconversion luminescence

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Chinese Physics B 2012年第7期21卷 241-249页

作者：何恩节刘宁章毛连秦炎福官邦贵李勇郭明磊 department of Physical and electronics Anhui Science and Technology University

By employing a certain proportion of hydrogen peroxide, ammonia, ammonium fluoride, and ethylene diamine tetraacetic acid （EDTA） as precipitator, well-crystallized LaOF：Eu3＋ and LaOF：Yba＋, Era＋ nanocrystals are synthe- sized by using the chemical co-precipitation method. The structural properties of these samples are characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and Fourier transform infrared spectroscopy （FTIR） spectra. The results show that all the samples have an average size below 70 nm, which decreases gradually with the increase of the EDTA content, and a certain number of EDTA molecules are coupled with doped ions on the surfaces of nanocrystals. Most of the doped ions are proved to be enriched on the surfaces of nanocrystals and surrounded by the high energy vibration groups and bonds in EDTA molecules. The observed differences in upconversion emission spectrum among the different LaOF：Yba＋, Er3＋ nanocrystals are explained by the different two-photon upconversion mechanisms. Especially, in the LaOF：Yba＋, Era＋ nanocrystals with EDTA, the two-photon processes that contain several special cross-relaxation processes are introduced to analyse the corresponding upconversion mechanisms.

关键词： surface effect nanocrystals cross relaxation

Study on eigenvalue space of hyperchaotic canonical four-dimensional Chua's circuit

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Chinese Physics B 2010年第3期19卷 137-144页

作者：李冠林陈希有 department of Electrical and electronics Engineering Dalian University of Technology

The eigenvalue space of the canonical four-dimensional Chua＇s circuit which can realize every eigenvalue for fourdimensional system is studied in this paper. First, the analytical relations between the circuit parameters and the eigenvalues of the system are established, and therefore all the circuit parameters can be determined explicitly by any given set of eigenvalues. Then, the eigenvalue space of the circuit is investigated in two cases by the nonlinear elements used. According to the types of the eigenvalues, some novel hyperchaotic attractors are presented. Further, the dynamic behaviours of the circuit are studied by the bifurcation diagrams and the Lyapunov spectra of the eigenvalues.

关键词： four-dimensional Chua's circuit eigenvalue space hyperchaos

A Polynomial Prediction Filter Method for Estimating Multisensor Dynamically Varying Biases

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Chinese Journal of Aeronautics 2007年第3期20卷 240-246页

作者： GAO Yu ZHANG Jian-qiu HU Bo department of electronics Fudan University Shanghai 200433 China

The estimation of the sensor measurement biases in a multisensor system is vital for the sensor data fusion. A solution is provided for the estimation of dynamically varying multiple sensor biases without any knowledge of the dynamic bias model parameters. It is shown that the sensor bias pseudomeasurement can be dynamically obtained via a parity vector. This is accomplished by multiplying the sensor uncalibrated measurement equations by a projection matrix so that the measured variable is eliminated from the equations. Once the state equations of the dynamically varying sensor biases are modeled by a polynomial prediction filter, the dynamically varying multisensor biases can be obtained by Kalman filter. Simulation results validate that the proposed method can estimate the constant biases and dynamic biases of multisensors and outperforms the methods reported in literature.

关键词： signal processing dynamic bias estimation simulation multisensor Kalman filter

Plasma Treatment of Aluminum Using a Surface Barrier Discharge Operated in Air and Nitrogen: Parameter Optimization and Related Effects

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Plasma Science and Technology 2013年第8期15卷 794-799页

作者： V. PRYSIAZHNYI Masaryk University Faculty of ScienceDepartment of Physical Electronics

This paper presents the results of aluminum surface treatment by diffuse coplanar surface barrier discharge. The goals are to study the effectiveness of the plasma treatment and the dependence of its efficiency on operation parameters, such as sample-to-electrode distance, treatment time or gas atmosphere. Three types of aluminum materials （bricks, sheets and thin films） were tested to ensure the reliability of the treatment. The changes in the surface properties were characterized by the surface free energy, atomic force microscopy, attenuated total reflectance Fourier transform infrared spectroscopy （ATR FTIR） and X-ray photoelectron spec- troscopy （XPS）. The influence of aging effect on the treatment was also measured and discussed.

关键词： aluminum surface treatment plasma treatment