The theory of the electrical breakdown of gases at atmospheric pressures

After a brief summary and discussion of Townsend's theory of the electrical breakdown of gases in the light of certain recent criticisms, it is shown that these are compatible with his theory except for one serious discrepancy. This discrepancy lies in the fact that at the assumed fields at which breakdown occurs in air, at atmospheric pressure, and in inert gases at low pressures, the $\text{β}\text{P}$ of Townsend's theory cannot have the significance given it by Townsend, as the positive ions are incapable at these fields of acquiring the ionizing energy. Various solutions proposed are discussed and found inadequate. It seems necessary, in order to keep this otherwise successful theory, to doubt the validity of the assumption generally made for plane parallel electrodes, that the potential drop between the plates is uniform before the spark passes. If fields about ten times as great as those calculated from the uniform drop existed, the theory could be applied. It is shown that such fields are possible under the conditions of the spark potential experiments, due to space charges resulting from the difference of ionic and electronic velocities. The existence of such fields requires a finite spark lag interval of about 10^?4 seconds, as yet not definitely observed. Experiments should be undertaken in laboratories equipped for the purpose to look for both the spark lag and the non-uniform field.     

The role of dissolved gases in determining the behavior of mineral insulating oils

The characteristics of gas solution in mineral oil are discussed. Data covering the changing gas solubility with temperature and pressure are given.The dielectric strength of oil is shown to be dependent on the kind and amount of its dissolved gas. The dielectric strength-gas content of oil bears a close relation to the recognized dielectric behavior of air itself.It is suggested that the usual dielectric strength of oil measures only the ease of oil “gassing” which may be dependent in part- at least, on dissolved impurities.     

小型创业企业生存分析

本文通过对小型创业企业相关数据的生存分析,使用生存表分析和半参数Cox模型,研究了小型创业企业的生存情况,通过数据分析,描绘了不同教育水平和性别的创业企业生存率表,通过对Cox模型预后因素的分析,建立了分层的Cox模型,模型表明教育水平对创业者的小企业创业生存影响显著。对模型的假设检验证明,文章建立的Cox模型是合理的。