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The secular effect of gravitational radiation damping on the periastronadvance of binary stars in second order perturbation theory

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Research in Astronomy and Astrophysics 2017年第8期17卷 81-88页

作者： lin-sen Li School of Physics Northeast Normal University Changchun 130024 China

The second order perturbation effect of gravitational radiation damping on the periastron advance of binary stars is *** second order analytic solution is obtained based on the first order theory in the 2014 article by *** results show that secular variation exists in the periastron advance of binary stars in the second order theory,but secular variation does not exist in the first order perturbation *** results for two compact binary stars(PSR J0737–3039 and M33 X-7)are given,demonstrating the theoretical significance even though the effect is very small.

关键词： binaries close—gravitational wave—celestial mechanics

Orbit and spin evolution of synchronous binary stars on the main sequence

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Research in Astronomy and Astrophysics 2012年第12期12卷 1673-1680页

作者： lin-sen Li School of Physics Northeast Normal UniversityChangchun 130024China

A set of synchronous equations are derived from a set of non-synchronous *** analytical solutions are given by solving the set of differential *** results of the evolutionary trend of the spin-orbit interaction are that the semi-major axis gradually shrinks with time;the orbital eccentricity gradually decreases with time until orbital circularization occurs;the orbital period gradually shortens with time and the rotational angular velocity of the primary component gradually speeds up with time before the orbit achieves *** theoretical results are applied to evolution of the orbit and spin of synchronous binary stars Algol A and B that are on the main *** circularization time,lifetime and the evolutionary numerical solutions of orbit and spin when circularization time occurs are estimated for Algol A and B.

关键词： binaries:close-rotation-evolution

Orbit and spin evolution of synchronous binary stars on the main sequence(a theoretical improvement to the analytical method)

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Research in Astronomy and Astrophysics 2015年第10期15卷 1695-1700页

作者： lin-sen Li School of Physics Northeast Normal University

This paper provides a method to study the solution of equations for syn- chronous binary stars with large eccentricity on the main sequence. The theoretical results show that the evolution of the eccentricity is linear with time or follows an exponential form, and the semi-major axis and spin vary with time in an exponen- tial form that are different from the results given in a previous paper. The improved method is applicable in both cases of large eccentricity and small eccentricity. In ad- dition, the number of terms in the expansion of a series with small eccentricity is very long due to the series converging slowly. The advantage of this method is that it is applicable to cases with large eccentricity due to the series converging quickly. This paper chooses the synchronous binary star V1143 Cyg that is on the main sequence and has a large eccentricity （e = 0.54） as an example calculation and gives the nu- merical results. Lastly, the evolutionary tendency including the evolution of orbit and spin, the time for the speed up of spin, the circularization time, the orbital collapse time and the life time are given in the discussion and conclusion. The results shown in this paper are an improvement on those from the previous paper.

关键词： binaries: close -- rotation -- evolution

Pointwise Approximation Theorems for Combinations and Derivatives of Bernstein Polynomials

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Acta Mathematica Sinica,English Series 2005年第5期21卷 1241-1248页

作者： lin sen XIE Department of Mathematics Lishui University Lishui 323000 P. R. China

We establish the pointwise approximation theorems for the combinations of Bernstein polynomials by the rth Ditzian-Totik modulus of smoothness wФ^r（f, t） where Ф is an admissible step-weight function. An equivalen... 详细信息

关键词： Bernstein polynomials Combinations and derivatives Ditzian-Totik modulus of smoothness Pointwise approximation

Theory of Dynamics In-Phase Locking and Quasi-Period Synchronization in Two Mutually Coupled Multi-Quantum-Well Lasers

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Communications in Theoretical Physics 2011年第3期55卷 481-488页

作者： YAN sen-lin Department of Physics and Electronic Engineering Nanjing Xiaozhuang University Nanjing 211171 China

Abstract We study dynamics in two mutually coupling multi-quantum-well lasers. We carry out theoretical and numerical analysis of synchronization, anti-synchronization, in-phase locking in the two identical lasers but detuning, in detain. It is proved that the coupling level determines stability of the lasers by analyzing the eigenvalue equation. Critical case of locking is discussed via the phase difference equation. Quasi-period and stable states in the two lasers are investigated via varying the current, detuning and coupling level.

关键词： in-phase locking synchronization multi-quantum-well laser coupling

Visuospatial Memory Alteration in Alzheimer’s Disease

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Neuroscience Bulletin 2020年第8期36卷 829-830页

作者： sen lin Department of Ophthalmology Daping HospitalArmy Medical Center of the People's Liberation ArmyArmy Medical UniversityChongqing 400042China

Although the treatment and drug discovery for Alzheimer’s disease (AD) are limited and some have failed recently,the search for potential biomarkers and early predictors *** is not only characterized by the decline o... 详细信息

关键词： Alzheimer impairment treatment

Controlling Chaos in a Semiconductor Laser via Weak Optical Positive Feedback and Modulating Amplitude

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Communications in Theoretical Physics 2007年第3期47卷 491-494页

作者： YAN sen-lin Physical Department Nanjing Xiaozhuang College Nanjing 210017 China

Numerical analysis of weak optical positive feedback （OPF） controlling chaos is studied in a semiconductor laser. The physical model of controlling chaos produced via modulating the current of semiconductor laser is presented under the condition of OPF. We find the physical mechanism that the nonlinear gain coefficient and linewidth enhance- ment factor of the laser are affected by OPF so that the dynamical behaviour of the system can be efficiently controlled. Chaos is controlled into a single-periodic state, a dual-periodic state, a tri-periodic state, a quadr-periodic state, a pentaperiodic state, and the laser emitting powers are increased by OPF in simulations. Lastly, another chaos-control method with modulating the amplitude of the feedback light is presented and numerically simulated to control chaotic laser into multi-periodic states.

关键词： chaos control positive feedback period

Reaction Effect of Gravitational Radiation of Rotating Ellipsoid as Central Body upon the Variation of Celestial Orbital Plane

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Chinese Physics Letters 1997年第5期14卷 328-331页

作者： LI lin-sen Department of Physics Northeast Normal UniversityChangchun 130024

The Reaction effect of gravitational radiation emitted from central body with quadrupole moment on the variation of celestial orbital plane was studied in *** derive the formulas for the relation between the variation of the inclination of the orbital plane and contraction of the orbital radius with *** expressions deduced were applied to the estimation for the evolution of the systems of planet-satellite(Jupiter-2 and Neptune-1).

关键词： orbital radius contraction

A Simple Method to Extract Tropical Monsoon Forests Using NDVI Based on MODIS Data:A Case Study in South Asia and Peninsula Southeast Asia

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Chinese Geographical Science 2016年第1期26卷 22-34页

作者： lin sen LIU Ronggao State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Distribution of monsoon forests is important for the research of carbon and water cycles in the tropical regions. In this paper, a simple approach is proposed to map monsoon forests using the Normalized Difference Vegetation lndex （NDVI） derived from the Moderate Resolution Imaging Spectroradiometer （MODIS） data. Owing to the high contrast of greenness between wet season and dry season, the monsoon forest can be easily discriminated from other forests by combining the maximum and minimum annual NDVI. The MODIS-based monsoon forest maps （MODMF） from 2000 to 2009 are derived and evaluated using the ground-truth dataset. The MODMF achieves an average producer accuracy of 80.0% and the Kappa statistic of 0.719. The variability of MODMF among different years is compared with that calculated from MODIS land cover products （MCD 12Q 1）. The results show that the coefficient of variation of total monsoon forest area in MODMF is 7.3%, which is far lower than that in MCD12Q1 with 24.3%. Moreover, the pixels in MODMv which can be identified for 7 to 9 times between 200l and 2009 account for 53.1%, while only 7.9% ofMCD12QI pixels have this frequency. Additionally, the monsoon forest areas estimated in MODMF, Global Land Cover 2000 （GLC2000）, MCDI2Q1 and University of Maryland （UMD） products are compared with the statistical dataset at national level, which reveals that MODMv has the highest R^2 of 0.95 and the lowest RMSE of 14 014 km^2. This algorithm is simple but reliable for mapping the monsoon forests without complex classification techniques.

关键词： monsoon forest Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index(NDVI) amplitude threshold classification