Cosmic ray power spectral variations. 3: Solar rotation periodicities

Earlier studies of the periodic changes in cosmic ray intensity by power spectral analysis provided some understanding of the daily variation in terms of ambient power. The solar rotation periodicities are investigated, using daily means of calgary neutron monitor data during 1965 to 1976. Significant peaks with periods of 27 and 13.5 days with varying magnitudes are observed

A preliminary study of a very large space radiometric antenna

An approach used to compute the size of a special radiometric reflector antenna is presented. Operating at 1 GHz, this reflector is required to produce 200 simultaneous contiguous beams, each with a 3 dB footprint of 1 km from an assumed satellite height of 650 km. The overall beam efficiency for each beam is required to be more than 90%

A general-purpose approach to computer-aided dynamic analysis of a flexible helicopter

A general purpose mathematical formulation is described for dynamic analysis of a helicopter consisting of flexible and/or rigid bodies that undergo large translations and rotations. Rigid body and elastic sets of generalized coordinates are used. The rigid body coordinates define the location and the orientation of a body coordinate frame (global frame) with respect to an inertial frame. The elastic coordinates are introduced using a finite element approach in order to model flexible components. The compatibility conditions between two adjacent elements in a flexible body are imposed using a Boolean matrix, whereas the compatibility conditions between two adjacent bodies are imposed using the Lagrange multiplier approach. Since the form of the constraint equations depends upon the type of kinematic joint and involves only the generalized coordinates of the two participating elements, then a library of constraint elements can be developed to impose the kinematic constraint in an automated fashion. For the body constraints, the Lagrange multipliers yield the reaction forces and torques of the bodies at the joints. The virtual work approach is used to derive the equations of motion, which are a system of differential and algebraic equations that are highly nonlinear. The formulation presented is general and is compared with hard-wired formulations commonly used in helicopter analysis

More Communication with Less Entanglement

We exhibit the intriguing phenomena of "Less is More" using a set of multipartite entangled states. We consider the quantum communication protocols for the {\em exact} teleportation, superdense coding, and quantum key distribution. We find that sometimes {\em less} entanglement is {\em more} useful. To understand this phenomena we obtain a condition that a resource state must satisfy to communicate a $n$-qubit pure state with $m$ terms. We find that the an appropriate partition of the resource state should have a von-Neumann entropy of ${\rm log}_{2} m$. Furthermore, it is shown that some states may be suitable for exact superdense coding, but not for exact teleportation.Comment: 7 pages, 1 tabl