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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

Controllability of Nonlinear Discrete Systems with Degeneracy

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Acta Mathematicae Applicatae Sinica 2023年第2期39卷 293-305页

作者： Yue LYU Xue-li TAN Xue YANG Yong li School of Mathematics Jilin UniversityChangchun130012China Center for Mathematics and Interdisciplinary Sciences Northeast Normal UniversityChangchun 130024China

This paper concerns the controllability of autonomous and nonautonomous nonlinear discrete systems,in which linear parts might admit certain *** introducing Fredholm operators and coincidence degree theory,sufficient conditions for nonlinear discrete systems to be controllable are *** addition,applications are given to illustrate main results.

关键词： nonlinear discrete systems controllability degeneracy Fredholm operators coincidence degree theory

Rapid genetic screening of Charcot-Marie-Tooth disease type 1A and hereditary neuropathy with liability to pressure palsies patients

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Neural Regeneration Research 2012年第32期7卷 2522-2527页

作者： Xiaobo li Xiaohong Zi lin li Yajing Zhan Shunxiang Huang Jin li Xuning li Xigui li Zhengmao Hu Kun Xia Beisha Tang Ruxu Zhang Department of Neurology Third Xiangya Hospital Central South University Changsha 410013 Hunan Province China Department of Ultrastructure School of Basic Medical Science Central South University Changsha 410078 Hunan Province China State Key Laboratory of Medical Genetics Central South University Changsha 410078 Hunan Province China

We used the allele-specific PCR-double digestion method on peripheral myelin protein 22 （PMP22） to determine duplication and deletion mutations in the proband and family members of one family with Charcot-Marie-Tooth disease type 1 and one family with hereditary neuropathy with liability to pressure palsies. The proband and one subclinical family member from the Charcot-Marie-Tooth disease type 1 family had a PMP22 gene duplication; one patient from the hereditary neuropathy with liability to pressure palsies family had a PMP22 gene deletion. Electron microscopic analysis of ultrathin sections of the superficial peroneal nerve from the two probands demonstrated demyelination and myelin sheath hyperplasia, as well as an ＇onion-like＇ structure in the Charcot-Marie-Tooth disease type 1A patient. We observed an irregular thickened myelin sheath and ＇mouse-nibbled＇-Iike changes in the patient with hereditary neuropathy with liability to pressure palsies. In the Charcot-Marie-Tooth disease type 1A patient, nerve electrophysiological examination revealed moderate-to-severe reductions in the motor and sensory conduction velocities of the bilateral median nerve, ulnar nerve, tibial nerve, and sural nerve. Moreover, the compound muscle action potential amplitude was decreased. In the patient with hereditary neuropathy with liability to pressure palsies, the nerve conduction velocity of the bilateral tibial nerve and sural nerve was moderately reduced, and the nerve conduction velocity of the median nerve and ulnar nerve of both upper extremities was slightly reduced.

关键词： Charcot-Marie-Tooth disease hereditary neuropathy with liability to pressure palsies peripheral myelin protein 22 gene mutation PCR-double digestion method myelin sheath action potentia neuropathology neural regeneration

Stable P-Harmonic Maps Between Finsler Manifolds

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Acta Mathematica Sinica,English Series 2010年第5期26卷 885-900页

作者： Jin Tang li Department of Mathematics Xiamen University Xiamen 361005 P. R. China

In this paper, we derive the first and second variation formulas for JC-harmonic maps between Finsler manifolds, and when F″≤ 0 and n ≥ 3, we prove that there is no nondegenerate stable F-harmonic map between a Rie... 详细信息

关键词： F-harmonic maps Finsler manifolds stability

Volume-preserving Fields and Reeb Fields on 3-manifolds

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Acta Mathematica Sinica,English Series 2006年第4期22卷 971-988页

作者： Hong Jun li Science College Xi'an Jiaotong University Xi'an 710049 P. R. China

Volume-preserving field X on a 3-manifold is the one that satisfies LxΩ = 0 for some volume Ω. The Reeb vector field of a contact form is of volume-preserving, but not conversely. On the basis of Geiges-Gonzalo＇s parallelization results, we obtain a volume-preserving sphere, which is a triple of everywhere linearly independent vector fields such that all their linear combinations with constant coefficients are volume-preserving fields. From many aspects, we discuss the distinction between volume-preserving fields and Reeb-like fields. We establish a duality between volume-preserving fields and h-closed 2-forms to understand such distinction. We also give two kinds of non-Reeb-like but volume-preserving vector fields to display such distinction.

关键词： Volume-preserving fields Contact forms Reeb-like fields Volume-preserving sphere Poisson matrices

Remarks on homoclinic solutions for semilinear fourth-order ordinary differential equations without periodicity

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Applied Mathematics(A Journal of Chinese Universities) 2009年第1期24卷 49-55页

作者： li Cheng-yue Dept. of Math. Central Univ. for Nationalities Beijing 100081 China

This paper mainly discusses the existence of nontrivial homoclinic solutions for nonperiodic semilinear fourth-order ordinary differential equation u^（4）＋pu″＋a（x）u-b（x）u^2=c（x）u^3=3arising in the study of p... 详细信息

关键词： homoclinic solution Mountain Pass Lemma Extended Fisher-Kolmogorov (EFK) equation Swift-Hohenberg (SH) equation

On spectral theory of the Riemann zeta function

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Science China Mathematics 2019年第11期62卷 2317-2330页

作者： Xian-Jin li Department of Mathematics Brigham Young University

Every nontrivial zero of the Riemann zeta function is associated as eigenvalue with an eigenfunction of the fundamental differential operator on a Hilbert-P′olya space. It has geometric multiplicity one. A relation between nontrivial zeros of the zeta function and eigenvalues of the convolution operator is given. It is an analogue of the Selberg transform in Selberg’s trace formula. Elements of the Hilbert-P′olya space are characterized by the Poisson summation formula.

关键词： Hilbert-Pólya space spectrum of operators zeros of zeta function

The Cycle Structure for Directed Graphs on Surfaces

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Acta Mathematica Sinica,English Series 2015年第1期31卷 170-176页

作者： Zhao Xiang li Department of Mathematics Minzu University of China

In this paper, the cycle structures for directed graphs on surfaces are studied. If G is a strongly connected graph, C is a ∏-contractible directed cycle of G, then both of Int（C,∏） and Ext（C,∏） are strongly connected graph; the dimension of cycles space of G is identified. If G is a strongly connected graph, then the structure of MCB in G is unique. Let G be a strongly connected graph, if G has been embedded in orientable surface Sg with fw（G） ≥ 2（fw（G） is the face-width of G）, then any cycle base of G must contain at least 2g noncontractible directed cycles; if G has been embedded in non-orientable surface Ng, then any cycle base of G must contain at least g noncontractible directed cycles.

关键词： Directed graph strongly connected directed cycles cycles space

Study on the method of optimal location on explosion events at near-source site

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Acta Seismologica Sinica(English Edition) 2001年第3期14卷 349-355页

作者： li Xue-zheng Xi’an China Institude of Geology China Seismological Bureau Beijing China

IntroductionEarthquake location is one of the inverse problems in seismology. The accurate earthquake source location is the basis of studies of earthquake images, the relation analysis between seismicity and tectonics, and the important parameters of earthquakes. It is also the basic data used to study the space distribution of aftershocks after a strong earthquake. The earthquake location accuracy mainly depends on reliability of the velocity models for the earth￠s crust, the reasonable design of the seismograph network, the accuracy of arrival time, and the location method used (ZHAO, 1983; ZHU, ZHAO, 1997; li, et al, 1999). The reliability of the velocity model directly influences loca-tion results. The reasonable seismograph network design can improve the location accuracy; otherwise it will in-troduce ill-conditioned equations and large location error. If arrival time is not accurate, for example, if the seismic phase is wrongly identified or the time service is inaccurate, large arrival time error will be produced, and the location results and real hypocenters will be discordant. Different location algorithms adopted will produce differ-ent location errors. The residual criterion chosen has influence on location results. Besides, whether the event is correctly associated also influences the location quality. In practice, it can often be seen that large location devia-tion introduced by wrong event association.

关键词： explosion earthquakes earthquake location simplex pedal point on radial line 文章编号:1000-9116(2001)02-0349-07