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Zhang W.,University of Shanghai for Science and Technology | Qiu L.,University of Shanghai for Science and Technology | Xiao Q.,University of Shanghai for Science and Technology | Yang H.,University of Shanghai for Science and Technology | And 2 more authors.
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

By means of the concept of the balanced estimation of diffusion entropy, we evaluate the reliable scale invariance embedded in different sleep stages and stride records. Segments corresponding to waking, light sleep, rapid eye movement (REM) sleep, and deep sleep stages are extracted from long-term electroencephalogram signals. For each stage the scaling exponent value is distributed over a considerably wide range, which tell us that the scaling behavior is subject and sleep cycle dependent. The average of the scaling exponent values for waking segments is almost the same as that for REM segments (∼0.8). The waking and REM stages have a significantly higher value of the average scaling exponent than that for light sleep stages (∼0.7). For the stride series, the original diffusion entropy (DE) and the balanced estimation of diffusion entropy (BEDE) give almost the same results for detrended series. The evolutions of local scaling invariance show that the physiological states change abruptly, although in the experiments great efforts have been made to keep conditions unchanged. The global behavior of a single physiological signal may lose rich information on physiological states. Methodologically, the BEDE can evaluate with considerable precision the scale invariance in very short time series (∼102), while the original DE method sometimes may underestimate scale-invariance exponents or even fail in detecting scale-invariant behavior. The BEDE method is sensitive to trends in time series. The existence of trends may lead to an unreasonably high value of the scaling exponent and consequent mistaken conclusions. © 2012 American Physical Society.

Li Z.,CAS Institute of High Energy Physics | Li D.,Xingtai College | Wu Z.,CAS Institute of High Energy Physics | Liu J.,CAS Institute of High Energy Physics
Journal of X-Ray Science and Technology | Year: 2012

Using the three slit collimation system with a divergent beam simplifies the design of a small angle X-ray scattering (SAXS) cameras and improves both flux and stability. To achieve the required low angle and a high spatial resolution, the collimation system must be optimized in the design and operation phases. Simulation of a slit divergent camera yields optimal distance between the beam defining slits and optimal distance between sample and detector at which the maximum SAXS resolution is achieved with a minimal parasitic scattering for any length of the SAXS camera. The narrower the beam defining slits and the longer the total camera length, the smaller the minimum resolvable angle and the higher the attainable resolution. © 2012 - IOS Press and the authors. All rights reserved.

Feng T.,Beijing Jiaotong University | Yan F.P.,Beijing Jiaotong University | Li Q.,Beijing Jiaotong University | Peng W.J.,Beijing Jiaotong University | And 4 more authors.
Laser Physics | Year: 2013

We report the configuration and operation of a wavelength-tunable single frequency and single polarization erbium-doped fiber laser (EDFL) with a stable and high optical signal to noise ratio (OSNR) laser output. A narrow-band fiber Bragg grating (NBFBG), a FBG-based Fabry-Perot (FP) filter, a polarization controller (PC) and an unpumped erbium-doped fiber (EDF) as a saturable absorber (SA) are employed to realize stable single frequency lasing operation. An all-fiber polarizer (AFP) is introduced to suppress mode hopping and ensure the single polarization mode operation. By adjusting the length of the NBFBG using a stress adjustment module (SAM), four stable single frequency and single polarization laser outputs at wavelengths of 1544.946, 1545.038, 1545.118 and 1545.182 nm are obtained. At room temperature, performance with an OSNR of larger than 60 dB, power fluctuation of less than 0.04 dB, wavelength variation of less than 0.01 nm for about 5 h measurement, and degree of polarization (DOP) of close to 100% has been experimentally demonstrated for the fiber laser operating at these four wavelengths. © 2013 Astro Ltd.

Feng T.,Beijing Jiaotong University | Yan F.-P.,Beijing Jiaotong University | Li Q.,Beijing Jiaotong University | Peng W.-J.,Beijing Jiaotong University | And 4 more authors.
Chinese Physics Letters | Year: 2012

We propose a stable and high optical signal-to-noise ratio (OSNR) compound linear-cavity single-longitudinal-mode (SLM) erbium-doped silica fiber laser. It consists of three uniform fiber Bragg gratings (FBGs) and two fiber couplers to form a simple asymmetric four-cavity structure to select the longitudinal mode. The stable SLM operation at the wavelength of 1544.053 nm with a 3 dB bandwidth of 0.014 nm and an OSNR of ∼60 dB was verified experimentally. Under laboratory conditions, a power fluctuation performance of less than 0.05 dB for 5 h and wavelength variation of less than 0.01 nm for about 150 min is demonstrated. Finally, the characteristic of laser output power as a function of pump power is investigated. The proposed system provides a simple and cost-effective approach to realize a stable SLM fiber laser. © 2012 Chinese Physical Society and IOP Publishing Ltd.

Li Q.,Beijing Jiaotong University | Feng S.,Beijing Jiaotong University | Peng W.,Beijing Jiaotong University | Liu P.,Xingtai College | And 3 more authors.
Microwave and Optical Technology Letters | Year: 2012

In this article, a simple approach for photonic generation of microwave signal using a dual-wavelength single longitudinal mode fiber ring laser is proposed and demonstrated.A narrow transmission band fiber Bragg grating (FBG) based Fabry-Perot cavity is used to select the longitudinal mode. A FBG with reflectivity of 99.5% is used together with 2-m unpumped erbium-doped fiber acting as saturable absorber. Stable dual-wavelength single longitudinal mode fiber lasers with a wavelength separation of approximately 0.057 nm are experimentally realized. By beating the dual-wavelength fiber lasers at a photodetector, photonic generation of microwave signal at 7.129 GHz is successfully obtained. Both of the laser emission and generated microwave signal have good stability at room temperature. Copyright © 2012 Wiley Periodicals, Inc.

Li Q.,Beijing Jiaotong University | Yan F.,Beijing Jiaotong University | Peng W.,Beijing Jiaotong University | Feng T.,Beijing Jiaotong University | And 4 more authors.
Optics Express | Year: 2012

A π phase shifted distributed feedback (DFB) laser based on single mode large effective area heavy concentration erbium-doped fiber (EDF) has been demonstrated. The homemade EDF was fabricated by the modified chemical-vapor deposition (MCVD) technique, and the 13cm long π phase shifted fiber grating was written in the intracore of the EDF. The erbium-doped concentration is 4.19 × 1025 ions/m3, the mode field diameter of the fiber is 12.2801 um at 1550 nm, the absorption coefficients of the fiber are 34.534 dB/m at 980 nm and 84.253 dB/m at 1530 nm. The threshold of the DFB laser is 66 mW, and the measured maximum output power is 43.5 mW at 450 mW pump power that corresponding to the slope efficiency of 11.5%. The signal-to-noise ratio (SNR) of the operating laser at 200 mW input power is 55 dB, and the DFB laser has a Lorentz linewidth of 9.8 kHz at the same input pump power. © 2012 Optical Society of America.

Gao G.,Xingtai College | Chang J.,Xingtai College
2011 2nd International Conference on Artificial Intelligence, Management Science and Electronic Commerce, AIMSEC 2011 - Proceedings | Year: 2011

The foreign trade balance is the balance of the total exports value minus imports of a country in one year. In the context of post-financial crisis era, summary the distribution, determinants and evolution of China's foreign trade since joining the WTO, provide basis reference for government deeply adjust the foreign trade policy. Using 2001-2009 data, analysised the characteristics and causes of China's trade balance distribute. © 2011 IEEE.

Zhang X.X.,China Three Gorges University | Dong L.L.,Xingtai College | Cai K.,China Three Gorges University | Li R.P.,China Three Gorges University
Advanced Materials Research | Year: 2013

This work describes a routine monitoring method for simultaneous determination of three classes of veterinary antibiotics (quinolones, sulfonamides, and tetracylines) in the aquaculture water. The selected eleven pharmaceuticals include four quinolones (enoxacin, ofloxacin, ciprofloxacin and lomefloxacin), four sulfonamides (sulfadiazine, sulfadimidine, sulfamethoxazole and sulfisoxazole) and three tetracyclines (tetracycline, chlortetracycline, and doxycycline). The entire procedures for pre-concentration by solid phase extraction (SPE) using Oasis HLB, and liquid chromatography-ultraviolet spectrometry (LC-UV) quantification were examined and optimized. The chromatographic separations were performed on a Kromasil 100-C18 (250 mm×4.6 mm, 5 μm) column, using 0.1% (v/v) formic acid in water and acetonitrile as mobile phase with gradient elution, and 280 nm as the detective wavelength. The recovery efficiencies were found to be 85-117% for quinolones, 81-109% for sulfonamides, and 84-110% for tetracyclines at three spiking levels (5, 10 and 50 μg/L). The developed method was applied to real water samples collected from four aquafarms located in Yichang, Hubei Province, China. Three or four tested antibiotics were detected in all water samples, with concentrations ranging from 0.65 μg/L to 4.33 μg/L. The method is convenient and rapid, and provides a quantitative measurement of multi-residue antibiotics without complex and expensive analytical equipment. © (2013) Trans Tech Publications, Switzerland.

Si Y.,Xingtai College | Wu N.,Xingtai College | Tan Y.,Xingtai College
International Journal of Simulation: Systems, Science and Technology | Year: 2016

The network public opinion refers to the social and political attitude expressed by people through the Internet, compared to traditional media, which has a strong real-time and deviation. According to the ideas of the GVSM, the text is expressed by the sememe space vectors of HowNet, and then the text similarity calculation is realized. It shows that can well solve the problem of semantic shift in public opinion analysis and make the effect of network public opinion analysis have a greatly improved. © 2016, UK Simulation Society. All rights reserved.

Zhang L.,Xingtai College | Wang Z.L.,Xingtai College
Applied Mechanics and Materials | Year: 2014

With the rapid development of leisure sports, leisure sports economy has become a new growth point of China's economy. It's difficult to evaluate the present situation of leisure sports development level, this paper uses Analytic Hierarchy Process to study. First, build a hierarchical analysis indication system structure model, and the description of each indicator; Then, in elucidating the basic idea of Analytic Hierarchy Process on the basis of a mathematical model, including the judgment matrix, the normalization process and the arithmetic average of three steps; Finally, calculate the weight of index system according to the steps of solution, and points out that the level of development impact on leisure sports four most important indicators. The research results can be system-related policies for government agencies, the development of leisure sports, building a harmonious society, such as providing new theoretical foundation and scientific methods. © (2014) Trans Tech Publications, Switzerland.

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