关于由方块图求传递函数的教学研究

介绍了由方块图求传递函数的简单易行的教学方法,并通过实例分析论证了方块图简化的基本方法和原则,得出了由方块图简化求传递函数步骤,可供同行进一步研究作参考.     

D-1-Partially efficiency-balance designs with at most two efficiency classes

A wide class of block designs admitting a simple analysis has been considered. The statistical properties of such designs have been indicated and the problems relating to their characterization and construction have been investigated.     

Constructing 1-rotational NRDFs through an optimization approach: new (46,9,8), (51,10,9) and (55,9,8)-NRBDs

In this paper we formulate the problem of constructing 1-rotational near resolvable difference families as a combinatorial optimization problem where a global optimum corresponds to a desired difference family. Then, we develop an algorithm based on scatter search in conjunction with a tabu search to construct many of these difference families. In particular, we construct three new near resolvable difference families which lead to an equal number of new 1-rotational near resolvable block designs with parameters: (46,9,8), (51,10,9) and (55,9,8). Our results indicate that this conjunction outperforms both scatter search and tabu search.     

耐温耐盐聚合物堵剂的制备及性能研究

针对高温高矿化度地质条件特点，合成了对苯乙烯磺酸钠–2–丙烯酰胺基–2–甲基丙磺酸–膨润土聚合物堵剂。采用不同浓度盐溶液、使用温度及时间评价其耐盐耐温性能，优化了携带液体系，采用岩芯模拟实验考察堵剂封堵效果及耐冲刷性能。结果表明：该堵剂在80130 ℃恒温放置60 d 后树脂的吸水率和强度基本保持不变，树脂耐温性能良好；在质量分数30% 的模拟盐水溶液中吸水率仍可达12.00 g
g..1，树脂的耐盐性能良好；树脂在含水40% 的乳化油中3 h 不膨胀；岩芯实验测定聚合物堵剂在高渗和中渗通道中封堵率达到99.96% 和96.41%，经30 PV 水长期冲刷封堵率仍可达95.12% 和94.43%。     

关于加权广义逆的三个矩阵乘积的不变性

利用矩阵D-AXC的最大最小秩,给出了矩阵AXC的乘积、秩以及值域的不变性,其中X为矩阵B的各种加权广义逆.     

"大跃进"时期"蚂蚁啃骨头"的机械加工方法的兴起

1958年,"大跃进"进入高潮,机械工业的发展呈现出诸多耐人寻味的现象。在当时特殊的背景下,"蚂蚁啃骨头"的机械加工方法得到了重视和推广。此加工方法涉及冷、热两大类的机械加工问题,其中"蚂蚁"主要是指所谓的"移动式"机床和"积木式"机床,而"骨头"则是指经铸、锻、焊接等方法处理后的大型工件。"蚂蚁啃骨头"的加工方法主要是依靠工人的经验所采取的一种代用的技术方法,它解决了当时机械加工行业的生产困难,但也被赋予了很强的政治色彩。这种加工方法从一个侧面反映了20世纪五六十年代中国装备制造的工业基础、技术水平,也展示出中国当代的政治、经济和文化等因素对技术发展的影响。     

Computational Examples of a New Method for Distribution Selection in the Pearson System

A considerable problem in statistics and risk management is finding distributions that capture the complex behaviour exhibited by financial data. The importance of higher order moments in decision making has been well recognized and there is increasing interest in modelling with distributions that are able to account for these effects. The Pearson system can be used to model a wide scale of distributions with various skewness and kurtosis. This paper provides computational examples of a new easily implemented method for selecting probability density functions from the Pearson family of distributions. We apply this method to daily, monthly, and annual series using a range of data from commodity markets to macroeconomic variables.     

中国市场条件下大单交易价格行为的不对称性研究

在中国证券市场选取大盘环境不同的时段,利用配对技术消除样本系统误差,对大单买卖价格冲击不对称性及该不对称与市场环境之间的关系进行了实证分析。研究表明:中国证券市场的大单买卖价格冲击存在显著不对称性,且该不对称性与市场环境相关。当大盘上涨时,买入订单的价格冲击均比卖出订单大,当大盘下跌时,卖出订单的价格冲击多数比买入订单要大。     

E-optimal design in irregular BIBD settings

When the necessary conditions for a BIBD are satisfied, but no BIBD exists, there is no simple answer for the optimal design problem. This paper identifies the E-optimal information matrices for any such irregular BIBD setting when the number of treatments is no larger than 100. A- and D-optimal designs are typically not E-optimal. An E-optimal design for 15 treatments in 21 blocks of size 5 is found.     

管理会计的创新与发展

社会经济环境变化和管理科学的发展,是影响管理会计发展的两个主要因素。21世纪新的经济和管理环境,迫使管理会计必须加以创新和发展。本文从管理会计观念、管理会计内容和管理会计的研究方法三个方面论述了管理会计的创新与发展。