Возбуждение и ионизация частицы в одномерной потенциальной яме нулевого радиуса предельно коротким световым импульсом

The Migdal sudden perturbation approximation is used to solve the problem of excitation and ionization particles in a one-dimensional potential of zero radius with an extremely short pulse. There is has only one energy level in such a one-dimensional the delta-shaped potential well. It is shown that for pulse durations shorter than the characteristic period of oscillations of the wave function of the particle in the bound state, the population of the level (and the probability of ionization) is determined by the ratio of the electric the area of ​​the pulse to the characteristic “scale” of the area inversely proportional to the area of ​​localization of the particle in a bound state.

A generic gust definition and detection method based on wavelet-analysis

Wind gusts can have destructive effects on many structures and objects deemed valuable to humans. The aviation industry, for example, views gusts as a major hazard. Their destructive effect is proportional to the momentum that a specific gust imposes onto an object. The actual definition of a gust has a strong influence on how its impact can be quantified. Existing gust definitions, however, are largely based on fixed parameters describing shape requirements and thresholds and are often developed only for specific use cases. These gust definitions do not provide a direct link to the physical impact a particular gust has on a structure or object. The overall goal of this study is to provide such a direct link. The application of a wavelet-analysis to a turbulence-resolving wind velocity signal allows for the localization of signal amplitudes in the period as well as in the time domain. In this paper, we use wavelet-analysis in order to develop a straight-forward method of deriving information about gusts from a wind velocity signal. In order to define what a particular gust might be, we suggest the specification of a characteristic period and amplitude in the time-domain. We define a generic gust as a section of a wind velocity signal, where the wavelet-analysis detects that characteristic amplitude to be matched or exceeded within that characteristic period. The characteristic amplitudes and periods are generic and span a two-dimensional space of generic gust definitions. The method can be applied to turbulence resolving simulation data as well as high-resolution wind velocity measurement data. It can detect gusts of any shape, it is unbiased regarding any specific use case and invariant to changes of the mean wind. We provide a detailed description of the method, its capabilities and demonstrate its application to high resolution wind velocity measurement data.

Comparative Study of Seismic Ground Motion Parameters in Deep-Cut and High-Fill Engineering before and after Ground Leveling

Because of lack of flat land, more and more deep-cut and high-fill engineering are being carried out in mountainous areas. The original geological formations are greatly changed by ground leveling. Therefore, it is very important to analyze the seismic parameters before and after ground leveling. In this paper, the seismic motion parameters before and after ground leveling of deep-cut and high-fill engineering are compared by the establishment of seismic response analysis model in different geological conditions. The results show that the peak acceleration and the characteristic period of the response spectrum are lower than those before excavation; But the results change when filling on the foundation of bedrock or the foundation where original cover soil layers have already existed. The peak acceleration and characteristic period of acceleration response spectrum increase more than those ground motion parameters before filling in this site. Besides, when filling in the bedrock site, the peak acceleration magnification tended to decrease, with the increase of the filling thickness, and the characteristic period tended to increase. Therefore, seismic ground motion parameters after ground leveling can be lower than those before ground leveling in excavation area, conversely, ground motion parameters are higher in fill area.

Study on the Characters of Seismic Response Spectra Based on China Financial Information Mansion

Rare study is done on floor response spectrum of super-high rise building, but it is an important condition for the seismic response analysis of floor subsidiary structure. Therefore, based on the early calculation model of China Financial Information Mansion, the floor response spectrum is calculated under different input ground motion. The floor and ground response spectrum is compared with each other from the seismic coefficient, dynamic amplification coefficient, characteristic period and the form of response spectrum. The results shows that: the floor seismic coefficient and the magnification coefficient are greater or smaller than the ground ones, the biggest difference of which is nearly 1 times; all the floor character period are greater than the ground ones, the biggest difference of which is over 60%; there are obvious differences between the floor and ground dynamic magnification factor spectra form under some conditions, of which the second peak of the former one is probably very large, even near to the peak of the first one, while the latter has no such phenomenon. Therefore, during the process of calculating the seismic response of floor subsidiary structure, it is necessary to consider the change of floor seismic coefficient, dynamic magnification factor, characteristic period and spectra form based on the main structure.

Correlation of Site Characteristic Period with Predominant Period of Ground Acceleration by a Simplified Model

Site characteristic period is an important index in seismic zonantion and seismic resistance design. The characteristics of the ground motions are conceptually related with site characteristics. A simplified single-layer model is used for simulating horizontal strata under seismic loading to calibrate the correlation of site characteristic period with the predominant period of ground motion. The analytical results show that the inputted motions were amplified considerably by the site typically for the period components which were close to the site characteristic periods; with the shear wave velocity of the soil layer decreases with respect to the initial shear wave velocity, the predominant period of ground motion increases; the site characteristic periods are consistent with the predominant periods of the ground motion.