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641.
In this paper we propose a particle classification system for the imaging calorimeter of the PAMELA satellite-borne experiment. The system consist of three main processing phases. First, a segmentation of the whole signal detected by the calorimeter is performed to select a Region of Interest (RoI); this step allows to retain bounded and space invariant portions of data for the following analysis. In the next step, the RoIs are characterized by means of nine discriminating variables, which measure event properties useful for the classification. The third phase (the classification step) relies on two different supervised algorithms, Artificial Neural Networks and Support Vector Machines. The system was tested with a large simulated data set, composed by 40 GeV/c momentum electrons and protons. Moreover, in order to study the classification power of the calorimeter for experimental data, we have also used biased simulated data. A proton contamination in the range 10−4–10−5 at an electron efficiency greater than 95% was obtained. The results are adequate for the PAMELA imaging calorimeter and show that the approach to the classification based on soft computing techniques is complementary to the traditional analysis performed using optimized cascade cuts on different variables. 相似文献
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643.
Ground vibrations induced by blasting are one of the fundamental problems in the mining industry and may cause severe damage to structures and plants nearby. Therefore, a vibration control study plays an important role in the minimization of environmental effects of blasting in mines. This paper presents the results of ground vibration measurement induced by bench blasting at Magnesite Incorporated Company (MAS) open pit mine in Turkey. The scope of this study is to predict peak particle velocity and to determine the slope of the attenuation curve for this site. For this purpose, the blasting parameters of 43 shots were carefully recorded and the ground vibration components were measured for each event. After carrying out statistical analysis, the site specific parameters were determined to predict the peak particle velocity. In the light of this analysis, the prediction graphics of maximum charge weight per delay versus distance for different damage criteria was proposed to be able to perform controlled blasting in order not to damage to the nearby structures, especially to the plant where rotary and shaft kilns have been established. 相似文献
644.
利用宁夏大峰矿特大爆破资料研究地震波的衰减特性 总被引:1,自引:1,他引:0
应用萨道夫斯基经验公式,研究2007年12月20日宁夏大峰矿特大爆破S波最大振幅的衰减特性,结果表明。银川盆地衰减比周边地区严重,大体可以看出银川盆地的东部边界和南部边界。在爆破点东73km和南122~151km.该结果和地质上给出的银川盆地的边界基本吻合。 相似文献
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646.
无临空面深层岩体爆破增渗模型试验相似律研究及相似条件的实现 总被引:1,自引:0,他引:1
依据所分析的无临空面深层岩体爆破增渗的特点,在模型试验相似理论基础上进行无临空面深层岩体爆破增渗模型试验相似律研究。结合内蒙某低渗透砂岩型铀矿工程地质及水文地质实际情况,根据所推导的模型试验相似准则,通过理论分析及试验研究,实现了模型试验的几何条件、边界条件、爆炸荷载及材料的相似,为实施爆破增渗模型试验打下基础。 相似文献
647.
The paper is focused on the estimate of the impact of the non-gravitational perturbations on the orbit of the Mercury Planetary Orbiter (MPO), one of the two spacecrafts that will be placed in orbit around the innermost planet of the solar system by the BepiColombo space mission. The key rôle of the Italian Spring Accelerometer (ISA), that has been selected by the European Space Agency (ESA) to fly on-board the MPO, is outlined. In the first part of the paper, through a numerical simulation and analysis we have estimated, over a time span of several years, the long-period behaviours of the disturbing accelerations produced by the incoming direct solar radiation pressure, and the indirect effects produced by Mercury’s albedo. The variations in the orbital parameters of the spacecraft, together with their spectral contents, have been estimated over the analysed period. The direct solar radiation pressure represents the strongest non-gravitational perturbation on the MPO in the very complex radiation environment of Mercury. The order-of-magnitude of this acceleration is quite high, about 10?6 m/s2, because of the proximity to the Sun and the large area-to-mass ratio of the spacecraft. In the second part of the paper, we concentrated upon the short-period effects of direct solar radiation pressure and Mercury’s albedo. In particular, the disturbing accelerations have been compared with the ISA measurement error and the advantages of an on-board accelerometer are highlighted with respect to the best modelling of the non-gravitational perturbations in the strong radiation environment of Mercury. The readings from ISA, with an intrinsic noise level of about $10^{-9}\,m/s^{2}/\sqrt{Hz}The paper is focused on the estimate of the impact of the non-gravitational perturbations on the orbit of the Mercury Planetary Orbiter (MPO), one of the two spacecrafts that will be placed in orbit around the innermost planet of the solar system by the BepiColombo space mission. The key r?le of the Italian Spring Accelerometer (ISA), that has been selected by the European Space Agency (ESA) to fly on-board the MPO, is outlined. In the first part of the paper, through a numerical simulation and analysis we have estimated, over a time span of several years, the long-period behaviours of the disturbing accelerations produced by the incoming direct solar radiation pressure, and the indirect effects produced by Mercury’s albedo. The variations in the orbital parameters of the spacecraft, together with their spectral contents, have been estimated over the analysed period. The direct solar radiation pressure represents the strongest non-gravitational perturbation on the MPO in the very complex radiation environment of Mercury. The order-of-magnitude of this acceleration is quite high, about 10−6 m/s2, because of the proximity to the Sun and the large area-to-mass ratio of the spacecraft. In the second part of the paper, we concentrated upon the short-period effects of direct solar radiation pressure and Mercury’s albedo. In particular, the disturbing accelerations have been compared with the ISA measurement error and the advantages of an on-board accelerometer are highlighted with respect to the best modelling of the non-gravitational perturbations in the strong radiation environment of Mercury. The readings from ISA, with an intrinsic noise level of about
in the frequency band of 3·10−5–10−1 Hz, guarantees a very significant reduction of the non-gravitational accelerations impact on the space mission accuracy, especially of the dominant direct solar radiation pressure. 相似文献
648.
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650.
在对不同掏槽形式进行对比分析的基础上,结合工程实例,试验分析了不同掏槽形式下的爆破效果,认为斜眼掏槽和直眼掏槽都存在各自的缺陷,提出采用和推广准直眼掏槽方式的建议。 相似文献