Developments in the negative-U modelling of the cuprate HTSC systems

The paper deals with the many stands that go into creating the unique and complex nature of the HTSC cuprates above Tc as below. Like its predecessors it treats charge, not spin or lattice, as prime mover, but thus taken in the context of the chemical bonding relevant to these copper oxides. The crucial shell filling, negative-U, double-loading fluctuations possible there require accessing at high valent local environment as prevails within the mixed valent, inhomogeneous two sub-system circumstance of the HTSC materials. Close attention is paid to the recent results from Corson, Demsar, Li, Johnson, Norman, Varma, Gyorffy and colleagues.Comment: 44 pages:200+ references. Submitted to J.Phys.:Condensed Matter, Sept 7 200

A miniaturised monopole wideband antenna with reconfigurable band rejection for WLAN/WiMAX

NoThis paper proposes a tuneable band-rejected miniaturised monopole antenna. The band-notching was achieved by printing an inner chorded crescent shape over the surface of the substrate. By placing a small varactor between the inner and outer arches, the centre frequency of each notch can be individually shifted downwards. The design of the proposed structure has a controllable rejection in the range from 2.38 to 3.87 GHz maintaining a wideband performance from 1.5 to 5 GHz based on VSWR ≤ 2. The antenna prototype was fabricated and tested. Simulated and measured results are performed and analysed. With a compact size, the proposed monopole antenna may well work as an internal antenna in a portable device