作者机构：
Nanhua Univ, Dept Math & Phys, Henyang 421001, Peoples R China.;E China Normal Univ, Dept Math, Shanghai 200062, Peoples R China.;[Ruan Hang; Zhang Lei; Long Teng] Beijing Institute of Technology
通讯机构：
Department of Mathematics and Physics, Nanhua University, China
关键词：
Population model;oscillation;convergence;permanence
摘要：
In this paper, the qualitative behavior of solutions of the bobwhite quail population model x(n+1) = ax(n) + bx(n)/(1 x(n-k)(p))(c), n = 0, 1, ..., where 0 < a < 1 < a + b, p, c is an element of (0, infinity) and k is a nonnegative integer, is investigated. Some necessary and sufficient as well as sufficient conditions for all solutions of the model to oscillate and some sufficient conditions for all positive solutions of the model to be nonoscillatory and the convergence of nonoscillatory solutions axe derived. Furthermore, the permanence of every positive solution of the model is also showed. Many known results axe improved and extended and some new results are obtained for G. Ladas' open problems.
作者机构：
[Zhu D.-M.] Department of Mathematics, East China Normal University, Shanghai 200062, China;Department of Mathematics and Physics, Nanhua University, Hengyang 421001, China;[Li X.-Y.] Department of Mathematics, East China Normal University, Shanghai 200062, China, Department of Mathematics and Physics, Nanhua University, Hengyang 421001, China
通讯机构：
[De-ming Zhu] D;Department of Mathematics, East China Normal University, Shanghai, China
关键词：
global existence;positive periodic solution;coincidence degree;distributed delay model
摘要：
By using the continuation theorem of Mawhin's coincidence degree theory, a sufficient condition is derived for the existence of positive periodic solutions for a distributed delay competition model {u'(t) = u(t)[r_1(t)-a_1(t)u(t)-b_1(t) ∫from x = -T to x = 0 of L_1(s)u(t+s)ds-c_1(t)∫from x = -T to x = 0 of K_1(s)v(t+s)ds], v'(t) = u(t)[r_2(t)-a_2(t)v(t)-b_2(t) ∫from x = -T to x = 0 of L_2(s)v(t+s)ds-c_2(t)∫from x = -T to x = 0 of K_2(s)u(t+s)ds], where r_1 and r_2 are continuous ω-periodic functions in R_+ = [0,∞), b_i (i = 1,2) is nonnegative continuous ω-periodic function in R_+ = [0,∞), b_i (i = 1,2) is nonnegative continuous ω-periodic function in R_+ = [0,∞), ω and T are positive constants, K_i, L_i ∈ C([-T,0], (0,∞)) and ∫from x = -T to x = 0 of K_i(s)ds = 1, ∫from x = -T to x = 0 of L_i(s)ds = 1, i = 1,2. Some known results are improved and extended.
作者机构：
[李先义; 王礼广] Department of Mathematics, College of Mathematics/Physics, Nanhua University, Hengyang 421001, China;[田泽荣] Department of Computer, Mathematics/Computer Science College, Hunan Normal University, Changsha 410081, China
关键词：
delay difference equation;global attractivity;positive semicycle;negative semicycle;periodic point of prime period two
摘要：
Several new sufficient conditions are given for the global attractivity of solutions of a kind of delay difference equations. They either include or improve some known results and put the study of Ladas' conjecture forward.
摘要：
By means of one photon absorption laser-induced resonance fluorescence at 599.5 nm the relative concentrations of the amidogen (NH2) radical in the ammonia (NH3) radio-frequency (rf) plasma source were measured under different discharge pressures and rf powers. The time dependence of the fluorescence which comes from the radiation 101-211 of the P-branches of the Σ vibronic sub-bands can be described by a single-exponential decay. The decay time of NH2(A2A1) Σ (0, 9, 0) rovibronic state was determined. The spatial dependence of the NH2 density in the discharge tube was measured.
