自由主义经济学家哈耶克

本文主要介绍哈耶克的自由主义思想.他从人的认知的有限性出发,论证自由的必要性;澄清自由的含义及其与法制的关系.他的另一重要思想是强调道德、法律等习俗均为文明演变的自发产物,而非人为设计的结果.哈耶克一生的工作都在为资本主义道德进行辩护,但本文也指出了这种辩护中存在的某些困惑之处.     

A.C.-induced Eddy currents

In many technical devices an a.c.-supplied “primary” magnetic field induces eddy-current flow in a “secondary” armature. Exact calculation of the overall field distribution is difficult, hence, the secondary field is often neglected in practice and only an estimate of the interaction is obtained. This paper outlines a general solution of the problem with both fields taken into account, and the specific model discussed shows how to proceed in more complicated cases.     

Residual currents in A.C. discharges.

A point by point determination is made of the residual current flowing during the reignition period of an a.c. arc between pure graphite electrodes in atmospheric air.The air pressure is varied from 0.14 to 5.4 atmospheres absolute and the gap varied from 1/4 to 5 mm. Alternating current of 6o cycles per second is supplied to the arc by a io Kv. power transformer and the r.m.s. discharge current is limited by ohmic resistance to values between o.o5 and 2 amperes. The residual current rises to a peak shortly after the voltage reverses and the current then decreases as the recovery voltage increases to its reignition value. The peak of the residual current increases directly with the r.m.s. current of the arc, and is essentially independent of both the length of the gap and the pressure of the gas. The reignition voltage is shown to be a function of the value of residual current existing just prior to ignition. The rate of decay of residual current decreases as gas pressure and gap length are increased.