国防科技重大工程多层次隐性知识传递模型——基于技术总成视角

为实现国防科技重大工程技术总成过程中多层次隐性知识的有效传递,本文融合系统动力学理论和知识管理理论,对基于技术总成的多层次隐性知识传递特点和过程进行分析,在此基础上,构建基于技术总成的多层次隐性知识传递模型。通过对模型平衡点的求解和稳定性分析得出多层次隐性知识有效传递的基本参数控制条件为:δ1,δ2>1,且传递效果与δ1,δ2正相关。最后,基于管理学视角,提出通过构建支撑知识交互的信息技术平台,建立高效的组合式激励机制和营造鼓励知识交流和创新的工程文化促进基于技术总成的国防科技重大工程多层次隐性知识的高效传递。     

谈谈"问题解决"在教学中的应用

在课堂教学中灵活运用“问题解决”教学法能较好地培养学生发现问题、解决问题的能力。     

模糊自校正PID液位串级控制系统设计与仿真

针对双容水箱液位控制问题,探讨了模糊控制理论在液位控制系统中的应用,提出了基于模糊自校正PID的串级液位控制方案,设计了一种模糊自校正PID控制器,并在此基础上对该双容水箱液位在3种不同控制方案,即单回路PID控制、串级控制以及基于模糊自校正PID的串级控制下的控制效果进行了Simulink仿真研究。结果表明,相对于常规单回路PID以及常规串级控制,基于模糊自校正PID的串级控制系统在超调量、调节时间、抗干扰等方面有更好的控制品质。     

具多滞量脉冲时滞差分方程解的振动性与非振动性

讨论具有多个滞量的脉冲时滞差分方程△x(n) + ∑mi=1pi(n)x(n-li) =0 ,n≥ 0 ,n≠nkx(nk + 1) -x(nk) =bkx(nk) ,k=1,2 ,3,…给出了方程解的振动与非振动的充分条件 ,有关振动性的结论同样适用于不带脉冲扰动条件的差分方程     

非线性中立型时滞微分方程解的振动性

近年来，对于中立型时滞微分方程已有许多好的结果，如文献[1][2]．本文将对非线性中立型时滞微分方程解的振动性进行讨论．     

一类四阶非线性波动方程整体解的存在性

借助线性问题的衰减估计，在一适当的Banach空间，利用整体迭代法证明了一类非线性四阶波动方程Cauchy问题整体解的存在性     

探讨一阶常微分方程两种积分因子的存在性及其应用

给出了一阶常微分方程M（x,y）dx＋N（x,y）dy=0存在形如u（x,y）=（1/（x^2＋y^2）^n）,u（x,y）=u（x^m,y^n）积分因子的充要条件,通过举例验证这些方法的有效性．     

亚纯函数与其微分多项式的值分布

通过研究亚纯函数的Nevanlinna值分布理论问题,并结合亚纯函数的小函数,及其微分单项式和微分多项式,得到一比较有趣的关于亚纯函数的计数函数密指量和微分多项式的不等式,此不等式改进了Fang,Yang及I Lahiri和S.Dewan等学者的结果。     

Comparison of different theoretical models estimating peak power output and maximal oxygen uptake in trained and elite triathletes and endurance cyclists in the velodrome

Abstract

The primary objective of this study was to examine the relationship between heart rate intensity and pedometer step counts in adolescents. To determine cardiorespiratory fitness, 106 participants (47 boys, 59 girls, mean age 14.2 years, s = 0.8) completed the Queen's College Step Test and were classified as having low, moderate or high cardiorespiratory fitness. Adolescents also completed a 10-min treadmill trial while wearing a pedometer and heart rate monitor. The participants were instructed to maintain their heart rate between 65 and 75% of their maximum heart rate while running or walking on a treadmill. A heart rate of 65–75% maximum was associated with 146 steps per minute (s = 22) in boys and 137 steps per minute (s = 22) in girls. Results of analysis of variance indicated that there was a main effect for level of fitness (F _2,102 = 9.36, P < 0.001). The correlation between mean steps per minute and estimated maximum oxygen consumption was statistically significant (r = 0.44, P < 0.001). The results from this study suggest that a step rate of 130 steps per minute is equal to 65–75% maximum heart rate in low-fit adolescents and achieving 130 steps per minute could be used as an initial goal to improve fitness.     

Structure characterization for the geopolymer of sodium silicate and metakaolin

1 Introduction 1 During the last decade a new kind of material called geopolymer has emerged as a viable alternative for many conventional cements and plastics. Geopolymer is inorganic polymer derived from metakaolin and sodium silicate solution. It can be synthesized at low temperature and have useful properties such as high compressive strength. It is stable at temperatures up to 800 °C and even 1150 °C while ordinary Portland cement loses its strength at 500 °C [1]. Several microstruct…