The present volume is concerned with two of the central questions of chemical dynamics. What do we know about the energies of interaction of atoms and molecules with each other and with solid surfaces? How can such interaction energies be used to understand and make quantitative predictions about dynamical processes like scattering, energy transfer, and chemical reactions? It is becoming clearly recognized that the computer is leading to rapid progress in answering these questions. The computer allows probing dynamical mechanisms in fine detail and often allows us to answer questions that cannot be addressed with current experimental techniques. As we enter the 1980's, not only are more powerful and faster computers being used, but techniques and methods have been honed to a state where exciting and reliable data are being generated on a variety of systems at an unprecedented pace. The present volume presents a collection of work that illustrates the capabilities and some of the successes of this kind of computer-assisted research. In a 1978 Chemical Society Report, Frey and Walsh pointed out that "it is extremely doubtful if a calculated energy of activation for any unimolecular decomposition can replace an experimental deter mination. " However they also recorded that they "believe[d] that some of the elaborate calculations being performed at present do suggest that we may be approaching a time when a choice between reaction mechanisms will be helped by such [computational] work.

Spacecraft TT&C and Information Transmission Theory and Technologies introduces the basic theory of spacecraft TT&C (telemetry, track and command) and information transmission. Combining TT&C and information transmission, the book presents several technologies for continuous wave radar including measurements for range, range rate and angle, analog and digital information transmissions, telecommand, telemetry, remote sensing and spread spectrum TT&C. For special problems occurred in the channels for TT&C and information transmission, the book represents radio propagation features and its impact on orbit measurement accuracy, and the effects caused by rain attenuation, atmospheric attenuation and multi-path effect, and polarization composition technology. This book can benefit researchers and engineers in the field of spacecraft TT&C and communication systems. Liu Jiaxing is a professor at The 10th Institute of China Electronics Technology Group Corporation.