C. Wood – författare
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4 produkter
4 produkter
Häftad, Engelska, 1981
976 kr
Skickas inom 3-6 vardagar
In the past few years, the concept of creating microwave antennas using microstrip has attracted increasing attention and viable practical designs are now emerging. The purpose of this monograph is to present the reader with an appreciation of the underlying physical action, up-to-date theoretical treatments, useful antenna design approaches and the overall state-of-the-art situation. The emphasis is on antenna engineering design, but to achieve this goal it has been necessary to delve into the behaviour of microstrip in a much wider sense and also include aspects of electromagnetic analysis. As a consequence, the monograph will also be of interest to microstrip circuit designers and to some extent those seeking electromagnetic problems of a challenging nature.The astronomical progress in miniaturising and integrating electronic circuits in the past decade has recently crerated a positive demand for a new generation of antenna systems. In principle, microstrip antennas are thin planar configurations that are leightweight, low cost, easy to manufacture and can be made conformal with the surfaces of vehicles, missiles etc. The compatibility of microstrip antennas with integrated electronics is another great advantage. However, the microstrip wavetrapping effects inhibit the radiation mechanism and must be taken into account in antenna design. Wave-trapping effects in substrates involve the study of surface waves and discontinuities in open waveguide structures. The microstrip antenna designer must therefore encompass many more effects than previously considered by microstrip circuit designers. It is for these reasons that the scope of this monograph is necessarily somewhat wider than the title may suggest.The ten chapters are a blend of introductory, practical and theoretical treatments and likely future developments are also highlighted. A good selection of past and current references are given and each chapter concludes with a helpful summary comment.
Häftad, Engelska, 2008
132 kr
Skickas inom 5-8 vardagar
E-bok
PDF, Engelska, 20121 132 kr
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Man is entering a new era as a result of advances in human reproduction. Techniques have been developed to assist in the creation of man-artificial insemination and, now, in vitro fertilization (IVF). Soon, other new methods, based upon current advances of the IVF procedure, will develop to improve the quality of human reproduction. The book describes the conceptual framework and details of technique concerned with in vitro fertilization and embryo transfer (ET). Edwards and Steptoe first described the technique of IVF and ET and the subsequent births of two normal babies. Since then, the success rate of the system has been improved by the use of fertility drugs to provide more oocytes and preincubation to mature the oocyte before fertilization. As a result of the continued research from Melbourne and Cambridge, more than 100 babies have been born. A free interchange of information between the Cambridge and Melbourne groups has led to a predictable success rate of 15%-20% per laparoscopy, and infertility centres all over the world are now copying the techniques. It is an appropriate time to inform doctors and scientists to help them understand the various procedures involved in IVF and ET. While many advances will occur in the future, the establishment of high success rates in several of the critical steps in the procedure-oocyte pick-up rate (90%), fertilization (>90%) and early embryo development (70%-90% )-signifies that some of the new techniques are stabilized sufficiently to warrant transmission of information by text, rather than scientific journal.
Häftad, Engelska, 1886
139 kr
Skickas inom 5-8 vardagar