The theory of the telephone receiver

The equations connecting the winding current and diaphragm motion of a telephone receiver under impressed simple harmonic electromotive and mechanical forces are formulated under: (I) The Maxwell flux theory; (2) the magnetizing-winding theory; (3) the Ampèrean resistanceless fixed molecular circuit theory of permanent magnetism; and (4) a general molecular orbital theory of ferromagnetism. On the latter theory it is found that the coupling coefficients M and N in the equations in question are in general different, in counter-distinction to the other three theories as hitherto formulated. The flux theory is shown not to be inconsistent with this result when certain dynamical phase relations are introduced into the static flux-magnetomotive force formula (Ohm's Law analog) always employed in this theory. The Ampèrean rigid circuit theory is criticized as an inadequate dynamical representation of ferromagnetism. The magnetizing-winding theory (dynamical) is reproduced in slightly generalized form.     

移动通信市场竞争实证研究

为了对3G时代的移动通信市场构建提供参考依据，采用EVA法衡量了我国移动通信运营市场中厂商的利润情况。结果显示，我国移动通信运营市场整体表现为竞争力不足，因此对新运营商的引入势在必行。     

Aircraft radio and navigation

The essential engineering features of aircraft radio and associated difficulties are discussed. Solutions to these problems are given although no attempt has been made to describe particular equipment. Two outstanding radio aids to aerial navigation are discussed and a new method described whereby these may be made to operate a visual indicator in such a way that it will not only tell the pilot whether he is off his course but which way he is off. A heterodyne beacon having certain remarkable directional properties is described.