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Professor Peter V.E. McClintock 《Contemporary Physics》2013,54(6):561-562
Radioactive substances may be present in air as dust, fume or vapour. very often attached to the natural aerosol. Many nuclides are produced in the upper atmosphere by the interaction of cosmic rays and atmospheric gases, and as a result of nuclear bomb tests. Radio-iodine has also been released accidentally from nuclear reactors. Radioactive vapours and aerosols have been used to study mass-transfer between airstreams and surfaces. The results are applicable to problems such as the travel and deposition of spores and pollen. 相似文献
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Professor G. W. Gibbons 《Contemporary Physics》2013,54(4):371-372
While high resolution electron microscopy has been in use for many years, with steadily improving image resolution, most modern microscopes can provide complementary information on the chemical composition of very small volumes of material. This advance is very important and enormously extends the range of practical applications for the electron microscope. This review describes the basic principles and techniques of high resolution imaging and analysis, in both the conventional and scanning electron microscope, noting in each case the resolution that may be achieved. 相似文献
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B. Ishak 《Contemporary Physics》2013,54(2):235-236
Applications of optogalvanic spectroscopy developed since the resurgence of interest in optogalvanic detection are reviewed. The optogalvanic effect is a change in the electrical properties of a discharge caused by illuminating the discharge with radiation having a wavelength corresponding to an atomic or molecular transition in the discharge. The general scheme of optogalvanic spectroscopy is presented, followed by a discussion of the gas discharge physics of the optogalvanic effect. Applications of optogalvanic detection in moderate resolution spectroscopy, in Doppler-free spectroscopy, and in analytic studies are discussed. 相似文献
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D. Ullmann 《The European physical journal. Special topics》2007,145(1):25-32
Ernst Florens Friedrich Chladni, the son of the rector of
the University of Wittenberg, studied law and philosophy at the
Universities of Wittenberg and Leipzig, wrote a dissertation in each
of these disciplines and became an experimentalist concerned with
sound and vibrations. Chladni's name is associated with the Chladni figures, and this is the first real effort to
experimentally investigate the nature of sound. In the lecture the
publications of Chladni are presented and, cursorily, his new
instruments, designed and built by the physicist. Chladni began to
tour half Europe in his own coach with sufficient space for his
musical instruments. He gave lectures on the physics of plate and
rod vibrations and included demonstrations of the figures and his
musical instruments. Chladni's work has had a profound influence on
the experimental advances in acoustics, room acoustics, in the
verification of theories of superposition of waves, in elasticity,
vibrational modes, sound velocities in various media, and much more.
The lecture presents a portrait of the scientist Chladni, the times,
and his contributions to experimental acoustics which influenced
research for many decades. 相似文献
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The successful investigations of r.f. effects in NGR were recently in progress [1–3]. The purpose of this paper is to pay
attention to some new theoretical results in this field which may be an object of the experimental realization. 相似文献
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