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Search Results: 1 - 10 of 51701 matches for " PEI Yan Long "
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Dynamical phase transition and self-organized critical phenomena in the two-dimensional gas lattice model

Gong Long-Yan,Tong Pei-Qing,

物理学报 , 2003,
Abstract: 应用数值方法研究了一种具有封闭边界条件的Manna沙堆模型——格气模型.通过模拟,发现 系统存在一个临界密度ρc≈0.684…,得到了相应的临界指数α≈0.452±0.02 ,并且还发现只有在特定的粒子数密度范围,系统才能体现出自组织临界性.
Characterizing localization properties of two spinless electrons in a one-dimensional Harper model with concurrence
Gong Long-Yan,Tong Pei-Qing,

中国物理 B , 2008,
Abstract: By mapping the Fock space of many local fermionic modes isomorphically onto a many-qubit space and using the measure of concurrence, this paper studies numerically the mode entanglement of two spinless electrons with on-site interaction $U$ moving in the one-dimensional Harper model. Generally speaking, for electrons in extended regimes (potential parameter $\lambda<2$), the spectrum-averaged concurrence $N\langle C\rangle$ first decreases slowly as $\lambda$ increases until its local minimum, then increases with $\lambda$ until its peak at $\lambda=2$, while for electrons in localized regimes ($\lambda>2$), $N\langle C\rangle$ decreases drastically as $\lambda$ increases. The functions of $N\langle C\rangle$ versus $\lambda$ are different for electrons in extended and localized regimes. The maximum of $N\langle C\rangle$ occurs at the point $\lambda=2$, which is the critical value in the one-dimensional single-particle Harper model. From these studies it can distinguish extended, localized and critical regimes for the two-particle system. It is also found for the same $\lambda$ that the interaction $U$ always induce the decreases of concurrence, i.e., the concurrence can reflect the localization effect due to the interaction. All these provide us a new quantity to understand the localization properties of eigenstates of two interacting particles.
Electronic properties of one-dimensional systems with long-range correlated binary potentials

Gong Long-Yan,Tong Pei-Qing,Zhou Zi-Cong,

中国物理 B , 2011,
A new tracking error detection method using amplitude difference detection for signal waveform modulation multi-level discs

Yan Ming-Ming,Pei Jing,Pan Long-Fa,

中国物理 B , 2010,
Abstract: The sub-land/sub-pit affects the characteristic of the tracking error signal which is generated by the conventional differential phase detection (DPD) method in the signal waveform modulation multi-level (SWML) read-only disc. To solve this problem, this paper proposes a new tracking error detection method using amplitude difference. Based on the diffraction theory, the amplitude difference is proportional to the tracking error and is feasible to be used for obtaining the off-track information. The experimental system of the amplitude difference detection method is developed. The experimental results show that the tracking error signal derived from the new method has better performance in uniformity and signal-to-noise ratio than that derived from the conventional DPD method in the SWML read-only disc.
A Study on Multiwavelet-based Image Denoising

FEI Pei yan,GUO Bao long,

中国图象图形学报 , 2005,
Abstract: Multiwavelets are developed in recent years. They are a new addition to the body of wavelet theory. They preserve many properties of single wavelets while overcoming limitations of single wavelets. In practice, they perfectly combine smoothness, short support, orthogonality, symmetry.ect. The existing algorithms of multiwavelets denoising only provide theories of denoising but there is no concrete performing method. Hence, multiwavelets are combined with HeurShrink denoising method in this paper. A feasible denoising method ,called MDH, is proposed and the denoising performances of D4 scalar wavelet are compared with that of MDH. The experimental results show that MDH is superior to D4 scalar wavelet in denoising via HeurShrink.
Study on the Properties of Surface Waves in Coated Ram Layers and Monostatic Rcsr Performances of the Coated Slab
Hai-Yan Chen;Pei-Heng Zhou;Liang Chen;Long-Jiang Deng
PIER M , 2010, DOI: 10.2528/PIERM09122101
Abstract: Relationships between the properties of surface waves in radar absorbing materials (RAM) layers and mono-static radar cross section reduction (RCSR) performances of a coated slab are studied. In this paper, two kinds of RAM were employed for double-layer coating. By changing the thickness of each layer and the order of RAMs, mono-static RCSR performances of the coated slab are studied. Simultaneously mono-static RCSR performances of a slab coated with equivalent medium of the considered RAMs in situ are calculated and compared with the previous ones in regard to the properties of surface waves. It is found that surface waves in between layers for various coated projects can be evaluated. Our results suggest that the optimal coated order for RAMs exists, and the method may be efficient for coating strategy with various kinds of RAMs. Electromagnetic scatterings of the equivalent medium exclude the effect of surface waves in between layers. Therefore, the equivalent medium theory is not appropriated for the research of electromagnetic scattering on lossy mediums.
Denoising of Mechanical Vibration Signals Using Quantum-Inspired Adaptive Wavelet Shrinkage
Yan-long Chen,Pei-lin Zhang,Bing Li,Ding-hai Wu
Shock and Vibration , 2014, DOI: 10.1155/2014/848097
Abstract: The potential application of a quantum-inspired adaptive wavelet shrinkage (QAWS) technique to mechanical vibration signals with a focus on noise reduction is studied in this paper. This quantum-inspired shrinkage algorithm combines three elements: an adaptive non-Gaussian statistical model of dual-tree complex wavelet transform (DTCWT) coefficients proposed to improve practicability of prior information, the quantum superposition introduced to describe the interscale dependencies of DTCWT coefficients, and the quantum-inspired probability of noise defined to shrink wavelet coefficients in a Bayesian framework. By combining all these elements, this signal processing scheme incorporating the DTCWT with quantum theory can both reduce noise and preserve signal details. A practical vibration signal measured from a power-shift steering transmission is utilized to evaluate the denoising ability of QAWS. Application results demonstrate the effectiveness of the proposed method. Moreover, it achieves better performance than hard and soft thresholding. 1. Introduction Safety of a mechanical system is very important for industry. The study of fault feature detection in machinery has thus received considerable attentions during the past decades. Among all detection methods, the most popular tool is vibration-based analysis. However, for the studies about practical mechanical vibration signals, noise is an inevitable factor in the measured signals which always inhibits the extraction of true signal signatures for diagnosis. Therefore, noise depressing in mechanical time series is an important issue for accurate fault diagnosis. Compared with conventional methods, as an effective analysis technique, wavelet transform is a frequently used tool for nonstationary signal processing in many fields. Various shrinkage strategies in the wavelet domain have been proposed for denoising. The most popular methods are VisuShrink, SureShrink, BayesShrink, and NeighShrink. Recently, several shrinkage functions have been modified for better noise reduction based on the above shrinkage approaches [1–8]. Chesneau et al. [1] presented a stein block thresholding algorithm for denoising -dimensional data. Taylor et al. [2] denoised single-molecule fluorescence resonance energy trajectories using wavelet detail thresholding. The paper [3] described a new shrinkage methodology based on non-Gaussian statistical modelling for multimodal image denoising. Liu et al. [4] explored a suitable threshold in a complete solution space using particle swarm optimization. The work [5] developed a
Improvement of Surface Electromagnetic Waves Attenuation with Resistive Loading
Hai-Yan Chen;Long-Jiang Deng;Pei-Heng Zhou;Jianliang Xie;Zhi-Wei Zhu
PIER Letters , 2011, DOI: 10.2528/PIERL11072202
Abstract: Electromagnetic properties of conventional radar absorbing materials (RAM) make it difficult to use them to provide remarkable surface electromagnetic waves (SEMW) attenuation with thin thickness at low radar frequencies such as in the UHF and L bands. In this paper, a composite structure realized by a grounded RAM slab covered by a resistive sheet is proposed. The use of a resistive sheet results in a significant increase of SEMW attenuation performance at low frequency, but almost no increase in its thickness. The electromagnetic scattering properties for a target coated with the RAM with/without covered by a resistive sheet are considered for interpreting the improvement of SEMW attenuation with resistive loading. Using a method-of-moments (MoM) computational scheme, we explore the performance of the proposed composite structure as radar backscattering suppression for a metal slab at low radar frequencies. It is found that the RAM with resistive loading has significantly increased SEMW attenuation at low frequencies, and advances the large incidence angle or grazing angle mono-static radar cross section (RCS) reduction of the coating slab further than the RAM without resistive loading case.
Existence and uniqueness of generalized monopoles in six-dimensional non-Abelian gauge theory
Shouxin Chen,Long Pei
Mathematics , 2010,
Abstract: In this paper, we established the existence and uniqueness of the spherically symmetric monopole solutions in SO(5) gauge theory with Higgs scalar fields in the vector representation in six-dimensional Minkowski space-time and obtain sharp asymptotic estimates for the solutions. Our method is based on a dynamical shooting approach that depends on two shooting parameters which provides an effective framework for constructing the generalized monopoles in six-dimensional Minkowski space-time.
Construction of a Vector Conferring Herbicide and Pest Resistance in Tobacco Plant

XIE Long_Xu,XU Pei_Lin,NIE Yan_Fang,TIAN Ying_Chuan,

生物工程学报 , 2003,
Abstract: 构建了含草甘膦抗性突变基因(aroAM12)和人工合成重组Bt抗虫基因(Bts1m)的植物表达载体pCM12_s1m。aroAM12基因的表达由CaMV35S启动子控制,Bts1m基因的表达由2E_CaMV35S启动子和Ω因子控制。通过农杆菌介导,将aroAM12和Bts1m基因转化到烟草中,转基因烟草通过在含草甘膦的MS培养基上筛选而获得。Southern blot分析表明所有经过草甘膦筛选出的转化植株都整合有aroAM12基因,约70%的转化植株同时整合有aroAM12和Bts1m基因。Northern blot、Immunodot blot分析进一步证明整合的两个基因在转录、翻译水平上均进行了表达,不同植株之间表达存在着差异。草甘膦抗性和虫试实验证明,获得的转基因烟草对草甘膦和烟青虫具有很强的抗性。
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