一阶具分段常时滞中立型脉冲微分方程的振动性与渐近性(英文)     

林敏  胡玲 《怀化学院学报》2010,29(11)

考虑了一阶具有分段常数时滞与逐段常数变元的非线性中立型脉冲微分方程{[x(t)-cx(t-[t])]′-p(t)f(x([t]))=0,t0,t≠k,x(k)=bkx(k-),k=1,2,….解的振动性与渐近性.得到了上述方程所有非平凡解非振动与非振动解渐近性的充要条件,所得到的结果推广了一些已有的结果.  相似文献   

两个新的积分不等式和一个算子范数关系式     

刘琼 《中国科学院大学学报》2015,32(3):398-403

利用权函数方法和拉普拉斯积分变换, 给出2个新的积分不等式和它们的等价式, 证明它们的常数因子是最佳的. 作为应用, 一方面通过选取一些特殊参数值, 获得一些有意义的结果;另一方面定义3个积分算子, 建立它们之间的一个范数关系式.  相似文献   

四阶常系数非齐次线性微分方程特解的解法     

蒋静  冯春华 《河池学院学报》2009,29(2)

在已有文献所给的解一元四次方程方法的基础上,给出了求解四阶常系数方程的详细步骤,同时,利用常数变易法和分部积分法,以及高等代数的相关知识,得到了在两种情况下四阶常系数非齐次线性微分方程特解的两个定理.  相似文献   

Moderate-domain pulmonary oxygen uptake kinetics and endurance running performance     

A. E. Kilding  E. M. Winter  M. Fysh 《Journal of sports sciences》2013,31(9):1013-1022

Abstract

The aims of this study were to determine if the primary time constant (τ) for oxygen uptake ([Vdot]O₂) at the onset of moderate-intensity treadmill exercise is related to endurance running performance, and to establish if τ could be considered a determinant of endurance running performance. Thirty-six endurance trained male runners performed a series of laboratory tests, on separate days, to determine maximal oxygen uptake ([Vdot]O_2max), the ventilatory threshold (V_T) and running economy. In addition, runners completed six transitions from walking (4 km · h^?1) to moderate-intensity running (80% V_T) for the determination of the [Vdot]O₂ primary time constant and mean response time. During all tests, pulmonary gas-exchange was measured breath-by-breath. Endurance running performance was determined using a treadmill 5-km time-trial, after which runners were considered as combined performers (n=36) and, using a ranking system, high performers (n=10) and low performers (n=10). Relationships between τ and endurance running performance were quantified using correlation coefficients (r). Stepwise multiple regression was used to determine the primary predictor variables of endurance running performance in combined performers. Moderate correlations were observed between τ, mean response time and endurance running performance, but only for the combined performers (r=?0.55, P=0.001 and r=?0.50, P=0.002, respectively). The regression model for predicting 5-km performance did not include τ or mean response time. The velocity at [Vdot]O_2max was strongly correlated to endurance running performance in all groups (r=0.72 – 0.84, P < 0.01) and contributed substantially to the prediction of performance. In conclusion, the results suggest that despite their role in determining the oxygen deficit and having a moderate relationship with endurance running performance, neither τ nor mean response time is a primary determinant of endurance running performance.  相似文献   

Discrimination of Visual Linear Velocities     

Charles H. Shea  Cheryl Northam 《Research quarterly for exercise and sport》2013,84(3):222-225

Abstract

The purpose of the present study was to determine velocity discrimination characteristics of subjects in a difference threshold paradigm. After recruitment, 180 male and female subjects were randomly assigned to 1 of 6 groups differentiated by the length of the stimulus runway and the subjects' orientation to the stimulus. Stimulus velocities were presented on a modified Bassin Anticipation Timer with presentation rate controlled by a programmed timer. The criterion velocities were 134.11, 268.22 and 402.33, cm/sec with variable velocities ranging 44.7 cm/sec above and below the criterion in 8.94 cm/sec increments. The method of constant stimuli was used with 198 trial pairs presented (constant 7 second stimulus presentation interval). The results indicated that the discrimination of horizontal linear velocity follows a prothetic continuum. That is, the just noticeable difference increased in proportion to the increase in the criterion velocity. In addition, the subjects' orientation to the stimulus and the viewing distance (length of runway) seemed to play little or no role in the discrimination process.  相似文献   

System Analysis for Oxygen Uptake Kinetics with Step and Pseudorandom Binary Sequence Exercise in Endurance Athletes     

Takayoshi Yoshida  Yoshiyuki Fukuoka  Richard L. Hughson 《Measurement in physical education and exercise science》2013,17(1):1-9

We examined whether the system analysis for step and pseudorandom binary sequence (PRBS) exercises could be useful to characterize oxygen uptake (VO₂) kinetics of female sedentary subjects and endurance athletes. Breath-by-breath VO₂ was determined during step- and PRBS-cycle ergometer exercises. The time course of the VO₂ kinetics was evaluated by the time constant of the second phase, which should reflect the adjustment of the oxidative metabolism at the skeletal muscle level. The VO₂ kinetics were significantly faster in long-distance runners than in sedentary subjects for both exercises. A significant relationship was observed in the VO₂ kinetics obtained from step and PRBS exercises. In each group, there was no significant difference in the VO₂ kinetics for step and PRBS exercises. These results indicated that the system analysis with PRBS exercises revealed the faster VO₂ kinetics in endurance athletes than in sedentary subjects.  相似文献   

关于伪脐子流形的一些性质     

纪永强 《湖州师范学院学报》2005,27(1):4-8

设M2u^n p 1(c2)是n p q维具有常截面曲率为c2的黎曼流形，M1^n p(c1)为M2^n p q(c2)中的n p维常曲率为c1的子流形，设M^n为M1^n p(c1)中具有平行平均曲率向量的紧致伪脐子流形，给出M^n在M1^n p(c1)中的截面曲率Rijij以及第二基本形式模长的平方σ满足一定的条件，从而得到M^n为M1^n p(c1)的全脐子流形．  相似文献   

Riccati方程的可积条件     

钱明忠  陈友朋 《洛阳师范学院学报》2005,24(2):24-26

黎卡提(Riccati)方程y′=p(x)y2+q(x)y+r(x)一般情况下是不可积的,本文利用变量变换先将Riccati方程化成二阶变系数齐线性方程,再化成二阶常系数线性方程.从而得到Riccati方程的若干可积条件.  相似文献   

常压空心器壁相对绝热特性的数学模型及应用     

傅和平  时永鹏  李青云 《洛阳师范学院学报》2006,25(5):51-52

运用热传导的基本原理,建立了一个关于空心器壁绝热特性的数学模型.运用该模型分析证明了常压空心器壁的绝热性能优于实心器壁的结论,在工程建筑领域有一定的应用价值.  相似文献   

一种求数项级数之和的新方法     

欧阳智敏 《宜春学院学报》2005,27(4):15-16,19

利用双曲函数列tank^kxcoshx（k=0，1，2，……），求出一些收敛数项级数的和，从而为数项级数求和提供了一种新方法．  相似文献