多股流换热器传递函数系数的理论确定方法

用数值模拟方法对一四股流板翅式换热器分别施加流量、进口温度的阶跃变化,获得其出口温度动态的响应曲线;用理论方法研究了其传染函数的系数,从而得到了四股流换热器的传递函数,并对其结果进行了分析,所得的四股流板翅式换热器的传递函数系数炎其自动控制试验提供了理论依据。     

有错检验情况下标准型抽样方案的设计

本文给出了在有错检验情况下标准型抽样方案的设计方法，讨论了误检概率ｐ，ｐ′对抽样方案的影响，并给出抽样方案的实际应用。     

战术移动通信网的频率复用技术研究

战术移动通信网的网络拓扑结构随战场环境的变化而变化,为此网络拓扑结构具有重组的能力,网络拓扑重组后必须进行链路频道的重新分配,文中提出的频道分配技术是在避免同频道干扰条件下任一频道可在全网内多次重复使用,以提高频道的重复利用率,同时分析了该情况下网络至少应拥有的频道数,以保证网络有足够的频道供分配。     

浅谈数学教学中的“问题解决”

浅谈数学教学中的“问题解决”张希来（南阳师专数学系，４７３０６１）“问题解决”被称为是继“现代化”和“回到基础”之后，国际数学教育界关注的热点，是数学教育改革的新潮流，目前在我国已经引起强烈反响，对此本文谈一些粗浅看法。ｌ“问题解决”的背景和意义１９...     

浅谈中国现代史教学中正面引导问题

浅谈中国现代史教学中正面引导问题张小满中国现代史距今时间较短，政治性较强，属于争论而仍未定论的问题较多，因此，在教学中对学生进行正面引导，对于学生形成正确的历史观、世界观、价值观，正确认识今天更有其重要性和现实意义．笔者在教学实践中认识到，要作到寓思...     

Biased Bootstrap Methods for Reducing the Effects of Contamination

Contamination of a sampled distribution, for example by a heavy-tailed distribution, can degrade the performance of a statistical estimator. We suggest a general approach to alleviating this problem, using a version of the weighted bootstrap. The idea is to 'tilt' away from the contaminated distribution by a given (but arbitrary) amount, in a direction that minimizes a measure of the new distribution's dispersion. This theoretical proposal has a simple empirical version, which results in each data value being assigned a weight according to an assessment of its influence on dispersion. Importantly, distance can be measured directly in terms of the likely level of contamination, without reference to an empirical measure of scale. This makes the procedure particularly attractive for use in multivariate problems. It has several forms, depending on the definitions taken for dispersion and for distance between distributions. Examples of dispersion measures include variance and generalizations based on high order moments. Practicable measures of the distance between distributions may be based on power divergence, which includes Hellinger and Kullback–Leibler distances. The resulting location estimator has a smooth, redescending influence curve and appears to avoid computational difficulties that are typically associated with redescending estimators. Its breakdown point can be located at any desired value ε∈ (0, ½) simply by 'trimming' to a known distance (depending only on ε and the choice of distance measure) from the empirical distribution. The estimator has an affine equivariant multivariate form. Further, the general method is applicable to a range of statistical problems, including regression.     

一种基于半导体光放大器的全光2R再生器

针对一种基于半导体光发大器(SOA)的全光2R再生器进行了研究。该再生器是利用半导体光放大器中的自相位调制效应所引起的频谱红移现象,通过在半导体光放大器后面放置光带通滤波器可以达到2R再生目的。在10 Gb/s、20 Gb/s以及40 Gb/s的时分复用信道上对该再生器的性能进行了验证,结果表明,该再生器结构适用于较高速率的光纤通信系统中。     

A hierarchy of lorenz curves based on the generalized tukey's lambda distribution

A hierarchy of Lorenz curves based on the generalized Tukey's Lambda distribution is proposed. Representations of the corresponding distribution and density function are also provided, together with popular inequality measures. Estimation methods are suggested. Finally, a comparison with other parametric families of Lorenz curves is established.     

平面二次曲线的一个性质

以一个反例指出了文［２］的不足之处，得到了一般平面二次曲线的一个重要性质