共查询到20条相似文献,搜索用时 0 毫秒
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A precision method of ionospheric height measurement is described. It utilises the method of coincidence as is used in the study of delayed nuclear reactions. The accuracy attained has been much higher than has hitherto been possible. In the present stage of development this has been ± 0.1 km., but with further refinements in the circuits it is possible to improve upon this. It is expected that the technique will be found very useful in studying small variations in height such as for studying the fine structure of the ionosphere, the tidal effects and similar cases. 相似文献
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A.K. Kerman 《Nuclear Physics A》1981,361(1):179-191
A general nuclear rotation including precession and wobbling motion is studied by the time-dependent variational method and a classical equation of motion is derived. The intrinsic wave function associated with the general rotational motion is constructed by making use of the constrained Hartree-Fock method and variables necessary in solving the equation are calculated. The method developed here is applied to a schematic extension of the Nilsson model. 相似文献
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The use of a solid state detector has enabled us to measure the contribution from 1s electrons separately by the coincidence technique. The discrepancy between the measured profile and the corresponding calculated ones shows that the approximations used in the calculations are poor. 相似文献
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Moiré topography method is a well-known non-contacting 3-D measurement method. Recently, the automatic 3-D measurement technique by moiré topography has been developed in order to apply to the engineering and medical fields. The projection moiré topography is very attractive because of its high measuring speed and high sensitivity. In this paper, using the two-wavelength methods of projection moiré topography was investigated to measure the 3-D shape of an object with 2π-ambiguity problems. Rapid measurement can be accomplished by the synchronization between CCD camera and projector. The experimental results prove that the proposed scheme is capable of finding absolute fringe orders, so that the 2π-ambiguity problems can be effectively overcome so as to treat large step discontinuities in measured objects. 相似文献
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M. Pessa 《Solid State Communications》1981,39(4):605-606
In the analysis of angle-resolved photoemission data for gold, Christensen suggested that the triangulation method of photoemission is inapplicable to materials with flat occupied electronic bands. We show that this argument is not fully justified because the accuracy of the triangulation method can be improved from what is obtained for the configuration discussed by Christensen by studying energy-coincident spectral features over an extended k?-region in a plane of the Brillouin zone. 相似文献
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C. Dauwe 《Applied Physics A: Materials Science & Processing》1981,24(3):279-285
The method of triple coincidence is optimized for the detection of the orthopositronium decay. Two positron sources 86-Ge
and 22-Na, are compared. The influence of sandwich thickness is described and a method for the correction for those effects
is given.
This work is supported by the International Atomic Energy Agency, Vienna, through research contract 2516/R.B. 相似文献
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In the measurement of fluorescent lifetime based on time correlation-single photon counting technique by means of TAC, due to the contamination of multi-photons a deviation of fluorescent lifetime measured from the expected value is experimentally studied. A correction function instead of a simple exponential function is used to fit the experiment data. The validation of the correction function is checked using the experimental data of several test samples: YAP, NaI(Tl) and LSO. The results show that the correction function well fits the data and the reasonable fluorescent lifetimes are obtained. 相似文献
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Experimental study of multi-photon contamination on the measurement of fluorescent decay time 下载免费PDF全文
In the measurement of fluorescent lifetime based on time correlation-single photon counting technique by means of TAC, due to the contamination of multi-photons a deviation of fluorescent lifetime measured from the expected value is experimentally studied. A correction function instead of a simple exponential function is used to fit the experiment data. The validation of the correction function is checked using the experimental data of several test samples: YAP, NaI(T1) and LSO. The results show that the correction function well fits the data and the reasonable fluorescent lifetimes are obtained. 相似文献
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Three photon yields and ratios have been measured for several copper containing substances. The different extents of positronium formation have been substantiated through Doppler broadening, angular correlation and magnetic quenching in angular correlation and in peak-to-valley ratios of singles spectra at different fields. Application to chemical characterisation is indicated. 相似文献
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S.M. Zhmodik N.V. Verkhovtseva E.V. Soloboeva A.G. Mironov N.A. Nemirovskaya R. Ili O.M. Khlystov A.T. Titov 《Radiation measurements》2005,40(2-6):532
Sediments of Lake Baikal drill cores VER-96-1 St8 TW2 (5332′15″E; 10756′25″N), (interval 181.8–235 cm from the sediment surface) were studied by means of SSNTD with the aim of defining uranium occurrence in the sediments and the uranium concentration. The neutron-fission ((n,f)-autoradiographic) method allowed a detailed study of uranium distribution of these Lake Baikal sediments within the Academicheskiy Ridge. Layered accumulations of uranium-bearing grained phosphorite, uranium-bearing particles of organic material, and abnormal uranium concentration in diatomite of unknown origin were discovered. 相似文献
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提出了自由电子激光(FEL)的一种可能应用.指出静电电子加速器驱动的FEL技术目前已有能力满足阈能反应分子法激光分离铀同位素的要求.阈能反应分子法由于只需一次激光激发,因此从原理上讲,它的一次分离系数很高,优于原子法与其他分子法,在高浓铀小规模(10kg/a)生产中有其可行性. 相似文献
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We propose a method for single-shot measurement of the carrier-envelope phase of high-intensity laser pulses. The method is based on observation of the electrons' spatial distribution ionized by a time-dependent polarization pulse generated by a combination of replicas of the measuring pulse. The dependence of the electrons' angular distribution on carrier-envelope phase, pulse width, delay between two combining components, and a peak intensity is calculated. Important experimental issues such as broadening of the angular distribution, Gouy phase, difference between the two replicas, and asymmetric pulse shape are also discussed. 相似文献
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Experimental study on the surface stress measurement with Rayleigh wave detection technique 总被引:1,自引:0,他引:1
In this paper, experimental study on the surface stress measurement of a metallic material based on the Rayleigh wave acoustoelastic theory is introduced. A Rayleigh wave acoustoelastic formula deduced by Husson is optimized to estimate the surface stress of the material. Two micro Rayleigh wave transducers with 5 MHz frequency one of which is used for acoustic pulse emitter and another for receiver are used to determine the time of flight of Rayleigh wave propagating in a certain distance along the surface of the material. The difference in time of flight between two ultrasonic signals obtained in stressed and unstressed object surface is identified by the digital correlation method. A specimen made of Q235 steel and applied with tensile load is used for calibration to obtain the acoustoelastic coefficients of Q235 steel. Furthermore, some principal factors which may result in errors in the experiment are discussed and some measurements are proposed to prevent these errors. Finally the surface stress of a cantilever beam is detected by the Rayleigh wave acoustoelastic technique and the experimental result is well compared with the theoretical value. 相似文献