ISSN:0010-7514    

DOI:10.1080/00107519608217533

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The search for a theory that explains the origin of galaxies and large-scale structure in the Universe is at an exciting stage. Observational advances, including measurements of the anisotropy in the cosmic microwave background and systematic surveys of galaxy redshifts, are confronting theoretical calculations of the distribution of matter produced by the action of gravity on small initial density fluctuations in the expanding Universe. Although the basic idea behind most theoretical models is simple, the details are complicated and there are many unknown parameters, such as the quantity and type of dark matter forming the bulk of the mass of the Universe. Consequently, at present, there are a number of contenders for a theory of structure formation but no single model can fit all the observational data completely satisfactorily.

ISSN:0010-7514    

DOI:10.1080/00107519608217534

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The development of new transmission electron microscopes with energy-filtering capability together with the increase in computer power over the past few years has enabled electron diffraction from inorganic crystals to become a quantitative and accurate science. With the introduction of new techniques and data analysis and with the advantage of a nanometre-sized probe, electron diffraction now rivals X-ray and neutron methods in many aspects of crystallography and solid-state physics. In this article, we have discussed two new developments which highlight the progress made in this area. First, a new method for ab-initio structure determination is explained and an example given to show its success. Second, energy-filtered diffraction patterns are used to refine the scattering potential of a crystal so that the bonding charge density can be reconstructed.

ISSN:0010-7514    

DOI:10.1080/00107519608217535

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In the next few years, we expect to see the beginning of a new branch of astronomy—gravitational wave astronomy. Space detectors, especially, will soon have the sensitivity to see the tiny changes in distance between separated masses that are produced by gravitational waves in Einstein's theory of General Relativity. One such space detector, named OMEGA, has been proposed to NASA as a future medium sized Explorer mission. This detector would be formed from six small miniprobes that are launched into high circular Earth orbit, two miniprobes at each of the vertices of a million-kilometre equilateral triangle. The probes track each other with lasers. By subtracting the measurements of the armlengths, a fine Michelson interferometer can be formed that will detect changes in distance of less than one picometre at time scales around 1000s. At this sensitivity, OMEGA will be able to detect gravitational waves from known galactic binary stars and from possible events involving the massive black holes that are expected to reside in the nuclei of many galaxies.

ISSN:0010-7514    

DOI:10.1080/00107519608217536

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107519608217537

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107519608217538

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A first Course in the Numerical Analysis of Differential Equations, in the series Cambridge Texts in Applied Mathematics By A. ISERLES 1996, £19·95, US$27·95 (pbk), pp. xvi +378. Cambridge University Press, ISBN 0521566554. Scope: textbook. Level: advanced undergraduate and postgraduate.

ISSN:0010-7514    

DOI:10.1080/00107519608217539

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107519608217540

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor