Changsha, China
Changsha, China

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Huang G.,Shanghai University | Huang G.,Shaoyang University | Huang G.,Hunan First Normal College | Hu J.,University of Houston-Victoria
Current Bioinformatics | Year: 2013

Mainly based on pKa (NH3 +) values of amino acid, a novel graphical method without degeneracy for protein sequences has been proposed firstly, which assists in viewing, aligning and comparing multiple sequences visually. Then, a new algorithm to extract a 40-dimensional numerical vector from graphical curves has been presented to characterize protein sequences. The similar relationship among sequences is computed by Euclidean distance on corresponding numerical vectors. Finally, our method is applied for similarity analysis of protein sequences on two data sets. The results are in agreement with the acknowledged view proved by a great deal of evidence from anatomy and hence demonstrate the validity of this approach. © 2013 Bentham Science Publishers.


Yin Z.,Hunan Normal University | Yin Z.,Hunan First Normal College
Journal of Computational Information Systems | Year: 2014

A variable string length artificial bee colony-based robust relevance vector regression algorithm is presented in this paper, and variable string length artificial bee colony algorithm is used to select the optimal parameters of robust relevance vector regression algorithm. Tourism evaluation is employed to test the evaluation performance of variable string length artificial bee colony-based robust relevance vector regression algorithm in the experiments. We employ multi-experiments to testify the evaluation performance of variable string length artificial bee colony algorithm-based robust relevance vector regression algorithm. The experimental results demonstrate that variable string length artificial bee colony algorithm-based robust relevance vector regression algorithm can outperform robust relevance vector regression algorithm or relevance vector regression algorithm. Copyright © 2014 Binary Information Press.


Zhang P.-K.,Hunan First Normal College
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2010

Through establishing and solving differential equation of motion of the loudspeaker's cone driven by low-frequency tone burst signals, the cone's motion was analyzed with MAPLE software, analytic expression of the cone's velocity-time relation and a way of describing its velocity-time curve were given. Factors affecting the speaker's transient characteristics were studied, and theoretical results were tested by experiment. In addition, a possible way was proposed to measure the speaker's quality factor Q. The results show that the characteristics of the front and back edges of the speakers are interrelated; both the speaker's mechanical quality factor (Q m) and its electrical quality factor (Q e) have equivalent influence on the characteristics of the front and back edges of the speaker. Total quality factor (Q t) really affects the speaker's transient characteristics. As to tone burst signals in a certain range of frequency, the smaller the Q t of the speaker, the better its characteristics of the front and back edges. But too small Q t leads to degradation of sound pressure frequency characteristics. When designing speakers, the transient response and sound pressure frequency characteristics should be comprehensively taken into consideration to determine the appropriate Q t.


Zhang J.,Hunan First Normal College | Zhang J.,Hunan University | Xiang Y.,Hunan University | Zhang L.,Hunan University | Li Y.,Hunan First Normal College
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2012

The influence of nonlinear dispersion effects on modulation instability (MI) in nonlinear metamaterials (MMs) is investigated and some new instability phenomena are revealed. Firstly, a general expression for MI gain, taking account of the effects of arbitrary high-order nonlinear dispersions, is derived. It is shown that all even-order nonlinear dispersion not only deforms the original instability regions, but also may lead to the appearance of new instability regions; while all odd-order nonlinear dispersion always suppresses MI irrespective of their signs. Then, the influence of second-order nonlinear dispersion (SND) induced by dispersive magnetic permeability is further analyzed. It is found that SND not only leads to the occurrence of MI inaccessible in ordinary materials, but also opens up a new instability window with an infinite modulation frequency range and the gain value increases monotonically with increasing modulation frequencies.


Zhang L.,Shenzhen University | Zhang L.,Changsha University | Liu K.,Shenzhen University | Zhong H.,Shenzhen University | And 4 more authors.
Optics Express | Year: 2015

We study both analytically and numerically the propagation dynamics of an initially chirped Airy pulse in an optical fiber. It is found that the linear propagation of an initially chirped Airy pulse depends considerably on whether the second-order dispersion parameter β2 and chirp C have the same or opposite signs. For β2C < 0, the chirped Airy pulse first undergoes an initial compression phase, then reaches a breakup area as depending on the values of C, and then experiences a lossy inversion transformation such that it continues to propagate with an opposite acceleration. The chirped Airy pulse is always dispersed during propagation in the case ofβ2C > 0. The impact of truncation coefficient and Kerr nonlinearity on the chirped Airy pulse propagation is also disclosed separately. © 2015 Optical Society of America.


Huang G.,Shaoyang University | Zhou H.,Shaoyang University | Li Y.,Hunan First Normal College | Xu L.,Shaoyang University
Journal of Theoretical Biology | Year: 2011

In order to compare different genome sequences, an alignment-free method has proposed. First, we presented a new graphical representation of DNA sequences without degeneracy, which is conducive to intuitive comparison of sequences. Then, a new numerical characterization based on the representation was introduced to quantitatively depict the intrinsic nature of genome sequences, and considered as a 10-dimensional vector in the mathematical space. Alignment-free comparison of sequences was performed by computing the distances between vectors of the corresponding numerical characterizations, which define the evolutionary relationship. Two data sets of DNA sequences were constructed to assess the performance on sequence comparison. The results illustrate well validity of the method. The new numerical characterization provides a powerful tool for genome comparison. © 2011 Elsevier Ltd.


Zhang J.,Shenzhen University | Zhang J.,Hunan First Normal College | Dai X.,Shenzhen University | Zhang L.,Shenzhen University | And 2 more authors.
Journal of the Optical Society of America B: Optical Physics | Year: 2015

We investigate modulation instability (MI) in a nonlinear oppositely directed coupler with a quadratic nonlinearity, where one channel is made from a positive-index material (PIM) and another channel is fabricated from a negative-index material (NIM), trying to identify the different MI properties from those in a conventional parametric gap system with grating. Both the analytic continuous wave (CW) solutions and dispersion relation are obtained. By using standard linear instability we in detail discuss how the ratio of the backward to forward propagating wave's power, the phase mismatch, and the coupled coefficient influence the dynamical behavior of MI. Large stable regions are found if the fundamental harmonics (FH) falls in the normal dispersion when compared to the case in the conventional Bragg grating with a quadratic nonlinearity where the CW solutions are unstable in most cases. In addition, we also observe the large stable regimes of the CW solutions even when the coupled strength for the second harmonics (SHs) is weaker than that of the FH. These findings suggest that the oppositely directed coupler with a NIM channel provides more ways to manipulate the MI and soliton. © 2015 Optical Society of America.


Zhang L.,Shenzhen University | Zhang L.,Changsha University | Zhang J.,Hunan First Normal College | Chen Y.,Changsha University | And 2 more authors.
Journal of the Optical Society of America B: Optical Physics | Year: 2014

The dynamic propagation of the finite-energy Airy pulse (FEAP) is studied numerically in the presence of higherorder effects, including Raman scattering, self-steepening (SS), and third-order dispersion (TOD). It is shown that the Raman-induced frequency shift (RIFS) of a FEAP can be tailored by varying the truncation coefficient of the FEAP. In particular, the combined effects of Raman scattering and SS (or TOD) on the nonlinear propagation of a FEAP are identified. It is found that both TOD and SS effects tend to slow down the RIFS during the nonlinear propagation of a FEAP. In addition, the simultaneous contributions of Raman, TOD, and SS effects to the nonlinear propagation of FEAP are further discussed. Compared to the conventional symmetric pulses, such as Sech pulses, the FEAP can generate a broadening spectrum that is extended toward the blue side, in addition to the conventional red-shifted components. These results demonstrate that the FEAP can be used for supercontinuum generation and broadband sources. © 2014 Optical Society of America.


Zhang J.,Hunan First Normal College | Zhang J.,Hunan University | Xiang Y.,Hunan University | Wen S.,Hunan University | Li Y.,Hunan First Normal College
Journal of the Optical Society of America B: Optical Physics | Year: 2014

Received August 5, 2013; revised November 10, 2013; accepted November 11, 2013; posted November 11, 2013 (Doc. ID 194853); published December 9, 2013 Controllable and dispersive magnetic permeability in negative-index materials (NIMs) offers greatly enhanced design freedom to alter the linear and nonlinear properties. This makes it possible for us to control the propagation of ultrashort pulses at will. In this paper, we will investigate the self-focusing of ultrashort pulses associated with anomalous nonlinear self-steepening (SS) effect and anomalous space-time focus (linear SS) effect in bulk NIMs with a nonlinear electric polarization, trying to disclose some unusual behaviors different from those in naturally positive-index materials. It is found that negative SS acts to push the peak intensity toward the trailing edge of a pulse and the resulting spectrum exhibits a broad redshifted trail; however, positive SS leads to the occurrence of the opposite situation in both temporal and spectral domains, that is, the peak intensity will move toward the leading edge of the pulse by shifting the spectrum toward the blue side. In addition, compared with the case in positive-index materials (PIMs), another most notable property of NIMs is that, whether self-focusing of ultrashort pulses will occur at the leading or the trailing edge can be manipulated freely by engineering the SS effect by choosing the size of split-ring resonator circuit elements. Our analysis is performed by directly numerically solving nonlinear Schrödinger equations as well as by using the moment method, both showing consistent results. These findings demonstrate that NIMs can provide us unique opportunities unattainable in PIMs to manipulate ultrashort pulse propagation. © 2013 Optical Society of America.


PubMed | Hunan First Normal College
Type: Journal Article | Journal: Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences | Year: 2014

As a widely recognized public health problem as well as prevalent and challenging to modern society, chronic insomnia is involved in wide brain areas (such as prefrontal cortex, anterior cingulate cortex, amygdala, hippocampus, and thalamus) and emotion-cognition neuro-circuit. It is closely related to the conditioned hyperarousal and the increased information process and/or the impaired inhibitory ability to withdraw from awaking state. Thus, some specific abnormal mode may exist in the emotion-cognition circuit, which is associated with abnormal cognition load, such as repeated retrieval/intrusion of aversive memories during night. Studies through the combination of multiple techniques including psychology, electrophysiology and neuroimaging methods are needed to further enhance the understanding of chronic insomnia.

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