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Current activity in the field of magnetic separation is reviewed in fundamental terms. The diverse subject matter is ordered into four main groupings whose characteristics are described in terms of numerous devices, both of present-day and historical significance. Existing as well as potential areas of scientific and commercial operation are discussed. The basic principles of recent major developments in high intensity magnetic Separation are closely examined.  相似文献   

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著名光谱化学专家P.w.J.M鲍曼斯于2008年10月26 日逝世,享年76岁. 鲍曼斯1932年生予荷兰,于阿姆斯特丹大学化学物理系毕业.1961年获博士学位.1961~1968年间在阿姆斯特丹大学任教,从事原子光谱分析,发射光谱光源激发机理的研究.1966年出版专集:"Theory of Spectrochemical Excitation"1968年他进入Eindhoven的Philips研究实验室,曾任该实验室主任研究员  相似文献   

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The behaviour of positrons below the inelastic collision threshold in rare gases can usually be completely accounted for in terms of the annihilation and elastic scattering cross sections for collisions between a positron and a single gas atom. Determining these cross sections has been the subject of many theoretical and experimental investigations. However the basic premise that the positron interacts with the gas atoms, one at a time, has been recently questioned by the yet unexplained results of some low-temperature experiments. This article discusses the annihilation and elastic scattering cross sections as they relate to the conventional picture of positrons in He, Ne, Ar, Kr and Xe gas; as well as the possibility of bound states for positrons in the gases at low temperatures.  相似文献   

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We consider a stable open queuing network as a steady non-equilibrium system of interacting particles. The network is completely specified by its underlying graphical structure, type of interaction at each node, and the Markovian transition rates between nodes. For such systems, we ask the question “What is the most likely way for large currents to accumulate over time in a network ?”, where time is large compared to the system correlation time scale. We identify two interesting regimes. In the first regime, in which the accumulation of currents over time exceeds the expected value by a small to moderate amount (moderate large deviation), we find that the large-deviation distribution of currents is universal (independent of the interaction details), and there is no long-time and averaged over time accumulation of particles (condensation) at any nodes. In the second regime, in which the accumulation of currents over time exceeds the expected value by a large amount (severe large deviation), we find that the large-deviation current distribution is sensitive to interaction details, and there is a long-time accumulation of particles (condensation) at some nodes. The transition between the two regimes can be described as a dynamical second order phase transition. We illustrate these ideas using the simple, yet non-trivial, example of a single node with feedback.  相似文献   

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An account of cooperation between Balls Park Teachers' Training College (for women), Hertford, and the Department of Science of Hatfield Technical College. Specially selected students from the Training College attend the Technical College on one day a week for a course in the Physical Sciences. The object of the course is to increase the scientific background of the students and possibly to encourage them to undertake some teaching of science in secondary modern schools.  相似文献   

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