旋翼式水表的流量方程式和特性曲线方程式

本文根据流体力学原理对旋翼式水表的驱动力矩和各种力矩进行了详细分析,建立了流量基本方程式。在此基础上,作者进一步导出了旋翼式水表的特性曲线方程式。理论特性曲线与实验结果基本一致。特性曲线方程能清晰地反映出水表各结构参数之间的关系及其对水表性能的影响,并能对实际特性曲线的形状作出较为园满的解释。本文提出的数学模型可作为旋翼式水表结构参数设计的依据,并为进一步改善水表性能提供了理论基础     

The Volume of Transactions and the Circulation of Money in the United States, 1950–1979

In the identity of exchange I distinguish between currency and bank payments on one side and several types of transactions and the transfer of idle money on the other. An attempt is made to measure these variables, with varying success. On the payments side I argue that currency velocity is constant (and low) and that the vast rise of bank money velocity is largely due to increased short-term investment of idle funds. The results suggest an upward shift in the level of transactions in 1968–1972, which I attribute to changes in the international role of the dollar.     

有关少儿足球队员速度训练的几个问题

根据中学生的年龄、特点进行业余训练 ,探讨如何在业余训练中抓住速度这个环节 ,培养少儿足球队员的速度和灵活性 ,并取得理想效果。     

均速管在两相流测量中总压孔开孔位置的确定方法

本文根据均速管流量计在气(汽)液两相流测量中存在的问题,提出了利用两相流速分布规律重新确定总压孔开孔位置的改进方法。针对垂直上升圆管中气液两相流的速度分布式,具体给出了开孔位置的计算方法及结果,由此得到的均速管如被用于两相流测量,在测量精度、测量范围上都有所改善。     

Inflationary Expectations in Israel: A Multiple Indicators Approach

This article derives unobservable short-term inflationary expectations in Israel from their postulated effects on the velocity of demand deposits and the nominal interest rate. A multiple-indicators model is estimated to assess the impact of inflationary expectations on these variables. The expectations-formation mechanism is estimated using a multiple indicators–multiple causes (MIMIC) model. This methodology allows us to test for the structural stability of the model and estimate the relative variances of the postulated error components. Moreover, this procedure contains a built-in specification test of the chosen expectations-formation mechanism.     

A STUDY OF THE RELATION BETWEEN RIVER REGULATION AND FLOOD CONTROL

Flood control is closely related to the rising level of the upstream. Thechange of the main current and the inshore current velocity is induced by thecompletion of the regulation work. Yet Flood Control Departments pay muchmore attention to the extent,the range and the law of the inshore current velocity increase,especially in the river reaches which have arduous tasks of floodcontrol. Flood Control Departments object to constructing regulation work sucnas groynes,because they have always thought regulation work may lead to theincrease in the inshore current velocity.This paper intends to expound on theinfluences of regulation work on the extent,range and law of the inshore current velocity through analyzing the data obtained from the scale model tests ofthe Jiepai Reach in the middle of the Yangtze River and also discuss the possi-bility of limiting increase of the inshore current velocity through properly ad-justing regulaton work,thus we can correct evaluation of the influence of theriver regulation o     

玻璃管空气预热器的优化设计

本文研究玻璃管空气预热器的优化问题,提出了管式空气预热器优化设计的通用计算机软件,并进行了实例计算。同时还对卧式空气预热器的经济流速和最佳风烟速比进行了讨论。     

涡轮流量计数学模型与优化设计

本文应用流体力学边界层理论,对涡轮流量计涡轮叶片受到的流体粘性阻力矩作了较详尽的理论分析,得到了粘性阻力矩的计算公式。公式表明,在层流流动时,粘性阻力矩与流量的3/2次方成正比;在湍流流动时与流量成13/7次方关系。从而导出了全新的涡轮流量计的数学模型。根据这一数学模型计算的涡轮流量计的特性曲线与实验结果甚为吻合。文中还提出了关于涡轮流量计临界雷诺数Re_(c1)的新概念。认为可以用Re_(c1)的值作为判别涡轮流量计特性曲线优劣的准则数,对仪表结构参数进行优化设计,以扩大仪表的量程比。