首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4篇
  免费   0篇
建筑科学   2篇
无线电   2篇
  2005年   1篇
  2002年   1篇
  1985年   2篇
排序方式: 共有4条查询结果,搜索用时 31 毫秒
1
1.
The object of this study is to evaluate the role of synoptic situations or the combination of several environmental parameters typical for regions close to big deserts, as possible exterior pathogenic factors, which give rise to a number of sometimes medically unexplained symptoms and disorders of human well-being. We suppose that one of the most important causes might be atmospheric electricity, whose role in human life, health and feelings can scarcely be exaggerated; in particular, our research is concentrated on the influence of electromagnetic fields on some subsystems of the human organism. Discussed below are the results of one of the initial stages of our research into the problem of the variations in the electrical state in connection with meteorological conditions in the surface atmospheric layer. The environmental electrical state is determined by either global electrical effects or local factors, as the content of the air column and the meteorological conditions in this volume are tightly connected with air streams. Especially in our region, located between the Mediterranean Sea and the huge African and Asian deserts, the direction, duration and speed of the winds must play the dominant role, due to their control over the content and concentration of air-suspended particles N(T). Desert winds bring increased N(T) of enlarged solid grains, mostly charged, hotter temperature T(0), dryness and other perturbations in the usual weather state and, finally, in the atmospheric electric field intensity E. Within limited intervals of wind speed V(w) (2-5 m x s(-1)) and concentration of enlarged solid grains N(T) (500-4500 grains cm(-3)), the correlation coefficients between E and N(T) and V(w) can reach more than 0.90. Outside these ranges, considerably increased N(T) or several combinations of wind direction with V(w) (not necessarily strong winds) lead to the principal change in the values of E and the form of its diurnal distribution from what is usual for stable weather. For moderately polluted air, the dependence of E on N(T) can be approximated well enough by a polynomial of the second degree; in a dust storm, this function is very close to the log-normal distribution.  相似文献   
2.
Dynamic breakdown of Ne and Ar gases biased to the prebreakdown stage, with and without absorption of very short duration incident N2laser pulses, is studied. Effects of bias and incident laser intensity are seen to be complementary. Laser illumination of the interelectrode gap causes gas breakdown at the cathode to take place at a faster rate and at lower breakdown threshold bias than without the illumination. Breakdown pulse shape varies according to gas composition and bias, and is much different from simple nonbreakdown "prebreakdown" responses to the laser pulses. The prebreakdown signals are attributed to photon-enhanced ionization in the focal volume between the electrodes, while the laser-triggered breakdown pulses are attributed to photon-enhanced excitation and diffusion of such neutral atoms to the high field gradient region near the cathode, where cascade ionization collisional effects are amplified.  相似文献   
3.
Nitrogen laser pulse irradiation of prebreakdown discharges in Ne and Ar result in pulse responses strikingly similar to those reported for dynamic optogalvanic signals. For the latter, response polarity depends primarily upon atomic transition. Here, it depends primarily upon bias. Nevertheless, analysis of the results points to similar internal processes within the gas concerning metastable generation and destruction. Photoionization-assisted electron heating is an additional photon process relevant here which changes relative populations of excited states and plays a key role in reversing prebreakdown signal response polarity. It can also explain the mechanism of reported electron temperature increase in optogalvanic experiments which cannot be explained on the basis of atomic transitions.  相似文献   
4.
Our general work has been dedicated to the problems connected with the influence of short-term changes of the atmospheric state on some medically unexplained human responses. What are the meteorological stimuli eliciting the transition between health and disease? There are many reports on the impact of humidity, winds or pollution on feelings of disease or discomfort. We suppose that the main influencing climatic factor, which could excite multiform biological reactions, is atmospheric electricity, E, whose parameters depend strongly on the content of the air column and on the meteorological conditions in this volume, especially along its ground path. A clear connection between wind speed Vw and coarse aerosol concentration N(T) with electric field intensity E exists only for limited intervals of Vw, and N(T). In these ranges, the mean correlation coefficients p(E; Vw) and p(E; N(T)) are usually up to 0.45. In quiet weather, rho is significantly larger than in the equinox seasons or in transferred weather situations. Strong winds or a considerably increased pollution level lead to fast and deep fading of E and even to principal changes in the form of its diurnal distribution from what is usual for stable atmosphere conditions, while weak air streams or a clear atmosphere have almost no influence on electric state variations.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号