General Dynamics

About: General Dynamics is a company organization based out in Fairfax, Virginia, United States. It is known for research contribution in the topics: Signal & Propellant. The organization has 5722 authors who have published 5819 publications receiving 85768 citations. The organization is also known as: GD & General Dynamics Corporation.

Effects of Chemical Binding on the Neutron Cross Section of Hydrogen

Abstract: Fermi derived the energy dependence of the neutron scattering cross section of hydrogen chemically bound such that it acts as a harmonic oscillator. For comparison with this theory, the total cross section was measured with a high- resolution crystal spectrometer for hydrogen bound in four materials. In zirconium and yttrium hydrides, in which chemical bonding is relatively isotropic, the predicted structure with discrete energy levels is observed. In the less isotropic magnesium hydride, there is some evidence of energy levels, although not clearly resolved. For water the variation in the cross section is smooth, with no evidence of energy levels. (auth) search for 12119 The perturbations of the energy levels of the hydrogen atom by a possible electric dipole moment of the proton, d, were obtained. The inhomogeneous equation for the first-order perturbation of the wave functions was solved analytically. The shifts of the energy levels are of the second order in d. In particular, there results a decrease of the Lamb shift between the 2S/sub 1/2 and 2P/sub 1/2/. levels. By equating this decrease to the maximum allowed by the approximate agreement between the experimental and theoretical values of the Lamb shift, it is concluded that the electric dipolemore » moment of the proton, d, must be less than 1.3 x 10/sup -13/ cm times the charge of the electron. Calculations wore also carried out for the shifts of the energy levels of deuterium produced by a possible electric dipole moment of the deuteron. (auth)« less

Fault tolerant memory system

Abstract: A fault tolerant memory system (100) having a triple bit error correction and quadruple bit error detection capability is disclosed using control logic (108) coupled to multiple decoders (102, 104) each having single bit error correction/double bit error detection capabilities. The memory system can also be provided with a sparing system which provides an additional memory device to circumvent failures in individual memory devices. The memory system is suited for severe environments such as computing systems operating in outer space.

Partitioning QoS management for secure tactical wireless ad hoc networks

Abstract: Addressing quality of service in military wireless ad hoc communication networks involves unique challenges due to imposed tactical requirements and,conditions, such as heterogeneous traffic with stringent-real-time and survivability requirements, mobile wireless nodes in hostile environments, and limited spectrum availability. Encryption adds another layer of complexity because of the partitioning of the network into plain text (unencrypted) and cipher text (encrypted) parts that, by definition, cannot communicate QoS information to one another. A typical communication shelter is composed of unencrypted LANs connected to a packet-encrypted backbone network. This article presents a partitioned QoS approach, focusing on QoS management at the unencrypted LAN that complements QoS management done at the encrypted backbone. Some of the unencrypted LAN QoS techniques being considered for the Warfighter Information Network-Tactical (the future Army tactical backbone network) are outlined.