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51.
A method for the deposition of BN onto graphite and other substrates is described. Boron trichloride (BCl3) and ammonia (NH3) diluted with Ar were used as reacting gases. The deposition process was carried out at 1300 K as well as lower temperatures in an open system at pressures of 1 atm. The consequences of the introduction of hydrogen to the system were considered. It was demonstrated that the replacement of argon with hydrogen increases the efficiency of the process as well as the theoretical rate of BN deposition. However, the acceleration of the deposition seems to be unprofitable, because the resulting supersaturation leads to the formation of an amorphous phase. The modification of the experimental conditions were proposed.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday 相似文献
52.
53.
给出动态随机弹性的概念及运算性质,讨论了动态随机弹性在期权定价模型中的应用.主要结果有:(1)在波动率为常数时,期权价格对的弹性,得到了动态随机弹性服从运动,并给出了相应的经济解释;(2)由于波动率一般不是常数,也是随机过程,因此本文进一步研究了期权价格对波动率的弹性,就股票价格的波动情况给出了数学描述和金融意义上的解释. 相似文献
54.
Q.J. Zhu 《Journal of Mathematical Analysis and Applications》2007,326(1):708-720
Investment systems are studied using a framework that emphasize their profiles (the cumulative probability distribution on all the possible percentage gains of trades) and their log return functions (the expected average return per trade in logarithmic scale as a function of the investment size in terms of the percentage of the available capital). The efficiency index for an investment system, defined as the maximum of the log return function, is proposed as a measure to compare investment systems for their intrinsic merit. This efficiency index can be viewed as a generalization of Shannon's information rate for a communication channel. Applications are illustrated. 相似文献
55.
After taking into account energy conservation and the particle’s self-gravitation interaction, Hawking radiation of the massive
particle as tunneling from Schwarzshild-anti-de Sitter black hole is studied by using Parikh-Wilczek’s semi-classical quantum
tunneling approach. Meanwhile, Hawking radiation as tunneling from the black hole is reexamined by developing Angheben–Nadalini–Vanzo–Zerbini
(ANVZ) covariant method to cover energy conservation and the particle’s self-gravitation interaction. Both the results perfectly
generalize those obtained by Parikh and Wilczek, and show that the tunneling rate is related to the change of Bekenstein-Hawking
entropy, and the factual emission spectrum is not exactly thermal, but satisfies the underlying unitary theory.
PACS: 04.70-s, 9760. Lf. 相似文献
56.
Those who have worked in the Royal Institution of Great Britain have, since its foundation in 1799, made significant contributions
to scientific knowledge, to its practical application, and to its communication to a wide variety of audiences. Such work
cannot be carried out in an architectural vacuum, and in this paper we examine how the buildings of the Royal Institution,
20 and 21 Albemarle Street in central London, have shaped the work undertaken within its walls and how, on a number of occasions,
the buildings have been reconfigured to take account of the evolving needs of scientific research and communication.
This paper is based on the Conservation Plan of the Royal Institution that we wrote during 2003. The Conservation Plan did
not examine the land owned by the Royal Institution to the north (i.e., 22 and 23 Albemarle Street; for this area see Richard Garnier, “Grafton Street, Mayfair,” Georgian Group Journal 13 (2003), 210–272), but it did discuss 18 and 19 Albemarle Street. In this paper we concentrate on the core Royal Institution
buildings at 20 and 21 Albemarle Street. Other studies of the relationship of architecture,space, and science include Crosbie
Smith and Jon Agar, ed., Making Space for Science: Territorial Themes in the Shaping of Knowledge (Basingstoke: Macmillan, 1997); Peter Galison and Emily Thompson, ed., The Architecture of Science (Cambridge, Mass.: MIT Press, 1999); and Sophie Forgan,“The architecture of science and the idea of a university,” Studies in History and Philosophy of Science 20 (1989), 405–434.
Frank A.J.L. James is Professor of the History of Science at the Royal Institution; he has written widely on the history of
nineteenth-century science in its social and cultural contexts and is editor of the Correspondence of Michael Faraday. He is President of the British Society for the History of Science. Anthony Peers is an Associate of Rodney Melville and
Partners where he works in the field of building conservation as an architectural historian. He is a Council member of the
Ancient Monument Society. 相似文献
57.
Peng Feng 《Journal of Mathematical Analysis and Applications》2007,329(1):347-356
In this paper we establish the exact blow-up rate of the large solutions of a porous media logistic equation. We consider the carrying capacity function with a general decay rate at the boundary instead of the usual cases when it can be approximated by a distant function. Obtaining the accurate blow-up rate allows us to establish the uniqueness result. Our result covers all previous results on the ball domain and can be further adapted in a more general domain. 相似文献
58.
59.
设Λ={λn}n∞=1为正的实数数列,且当n→∞时,有λn↘0.本文给出了当λn≤Mn-1/2,n=1,2,…,(其中M>0为一正常数)时Müntz系统{xλn}的有理函数在Lp[0,1]空间的逼近速度,主要结论为Rn(f,Λ) Lp≤CMω(f,n-1/2)Lp,1≤p≤∞. 相似文献
60.