Evolution Strategies for Mobile Telephony Employing Multiple Coexisting Technologies

In many countries, the analogue Advanced MobilePhone System (AMPS) is progressively being replaced bydigital technologies, with the intention of maximizingcapacity and service quality. This paper considers strategies for the evolution of mobiletelephony services, employing several coexistingmultiple access technologies, such as Code DivisionMultiple Access (CDMA) and Global System for Mobile(GSM), in recovering the spectrum previously used byanalogue technologies such as AMPS. We propose partialspectral overlay and interference control strategies forCDMA systems overlaying AMPS and GSM systems, to provide smooth transition paths for introducingthe CDMA technology, and we show that these overlaystrategies lead to significant increases in overallnetwork capacity.     

Knowledge transfer mechanisms for advanced surface engineering technologies

Abstract

A breakthrough in the area of PVD/CVD coating technologies, as in other surface engineering technologies, requires not only technical innovation but also innovative technological and organisational support. The cohesion of these diverse areas forms a basis for obtaining theoretical and physical models, which give rise to prototypes for the rapid application of breakthrough solutions. Mechanisms and structures aimed at reaching breakthrough research objectives are presented, taking as an example the investigation and application of new materials, particularly using surface engineering PVD plasma technologies. The advanced technology of thermal barrier coatings (TBC) is described and the associated process development, including the design and construction of a unique hybrid device for TBC creation, are presented. By means of this example, a combination of breakthrough and incremental research is explored and a real path for balancing research and knowledge transfer, leading to innovative solutions and technologically advanced product application, is demonstrated.     

Electron meets nitrogen: combination of electron beam hardening and nitriding

Abstract

Combined heat treatments, also known as duplex or hybrid technologies, offer new structure/property relationships in layered matrix compounds. The treatment sequence is critical. There are within reach both properties and property gradients that are impossible to achieve using the respective single treatment processes alone nor by simple addition of the effects of the single processes. Good technical progress is given by the combination of thermochemical treatment with high energy beam surface hardening, in particular electron beam hardening. After a historical survey (milestones) of the combination of thermochemical with thermal (surface) heat treatment technologies, the paper deals with the principles of the combining electron beam hardening after nitriding and vice versa , electron beam hardening before nitriding and the effects on microstructure and properties. Typical examples of industrial application are discussed. In this field of heat treatment, further development is focused on combinations of high energy beam hardening (electron or laser beam) with hard coating.