关于AR-MA双重时序模型平稳解的存在性

本文在参考文献[1]、[2]的基础上讨论了AR-MA双重时序模型存在平稳解的条件,获得了AR(1)-MA(1)和AR(1)-MA(2)存在平稳解的充要条件(不必假定白噪声序列为正态)。本文的方法完全适用于讨论一般的AR(1)-MA(q)模型的平稳解的存在性,而且对讨论AR-AR模型也有所启发。     

符号计算与非线性偏微分方程精确行波解

In this paper, with the aid of the symbolic computation, a further extended tanh function method was presented. Based on the new general ansatz, many nonlinear partial differential equation（s）（NPDE（s）） can he solved. Especially, as applications, a compound KdV-mKdV equation and the Broer-Kaup equations are considered successfully, and many solutions including periodic solutions, triangle solutions, and rational solutions are obtained. The method can also be applied to other NPDEs.     

氦原子~3D~e双激态中的电子云分布

本文以氦原子~3D~e双激态中的N=3,n=4序列为例,通过形状密度的分析和分波分析,研究了~3D~e态中的电子云分布.详细给出了这些态中电子间的角关联、径—角关联和径—径关联,发现了电子云分布的各何异性.除了比较这些态与总轨道角动量L≤1的态中的电子关联的差异之外,还对属于同一超多重态的~3D~e、~1D~3、~1P~0和~3P~e诸态的“类转子结构”进行了比较,     

一类随机微分效用的风险厌恶性

通过倒向重随机微分方程引入了一类随机微分效用,讨论其风险厌恶性。     

Energy expenditure and dietary intake in professional football players in the Dutch Premier League: Implications for nutritional counselling

ABSTRACT

Selecting effective dietary strategies for professional football players requires comprehensive information on their energy expenditure (EE) and dietary intake. This observational study aimed to assess EE and dietary intake over a 14-day period in a representative group (n = 41) of professional football players playing in the Dutch Premier League (Eredivisie). Daily EE, as assessed by doubly labelled water, was 13.8 ± 1.5 MJ/day, representing a physical activity level (PAL) of 1.75 ± 0.13. Weighted mean energy intake (EI), as assessed by three face-to-face 24-h recalls, was 11.1 ± 2.9 MJ/day, indicating 18 ± 15% underreporting of EI. Daily EI was higher on match days (13.1 ± 4.1 MJ) compared with training (11.1 ± 3.4 MJ; P < 0.01) and rest days (10.5 ± 3.1 MJ; P < 0.001). Daily carbohydrate intake was significantly higher during match days (5.1 ± 1.7 g/kg body mass (BM)) compared with training (3.9 ± 1.5 g/kg BM; P < 0.001) and rest days (3.7 ± 1.4 g/kg BM; P < 0.001). Weighted mean protein intake was 1.7 ± 0.5 g/kg BM. Daytime distribution of protein intake was skewed, with lowest intakes at breakfast and highest at dinner. In conclusion, daily EE and PAL of professional football players are modest. Daily carbohydrate intake should be increased to maximize performance and recovery. Daily protein intake seems more than adequate, but could be distributed more evenly throughout the day.     

两个新的矩阵特征值包含区域

引人广义a-对角占优矩阵和广义双a-对角占优矩阵概念,给出判定它们的充分必要条件,并由此获得了矩阵特征值的两个新包含区域,证明新的特征值包含区域包含于最近几个文献所给的特征值包含区域,因而能更精确地确定矩阵特征值的位置．     

准幻方矩阵的几个性质

讨论了准幻方矩阵的几个性质,得出了一些新的结果。     

双warped积流形之间2-调和的积映射

讨论了积映射Φ2=φ×ψ和2个广义的投影φ和ψ的2-调和性,得到了几个主要结论：Φ2=φ×ψ是恰当2-调和映射的充分必要条件是函数b,f分别为方程-1/f2 Jφ（dφ（grad（lnb）））＋n/2grad dφ（grad（lnb））2=0,-1/b2Jψ（dψ（grad（lnf）））＋m/2grad dψ（lnf）=0的非常值解;Φ2=φ×ψ是恰当2-调和映射的充分必要条件是φ和ψ都是恰当2-调和映射.     

关于双非线性抛物组解的有界性

单个双非线性抛物方程解的有界性结果推广到对角型双非线性抛物组情形时，无论对结构系数的可积性要求或对未知解的可积性要求．都要相应加强，本文考虑一类特殊结构双非线性对角型抛物组，在相应于单个双非线方程情形的同样可积性限制下，得到解的有界性。     

一类非线性退缩抛物方程的Cauchy问题

讨论带吸收项的非线性双重退缩抛物方程ut =div(| um|p-2 um) -uq 具有初值u(x ,0 ) =μ∈L∞loc(RN)的Cauchy问题 .利用正则化方法 ,首先得到了正则化问题非负古典解的一致估计 ,最后在初值满足一定的增长条件下 ,证明了双重退缩抛物方程Cauchy问题弱解的存在性与不存在性 .