Interdisciplinary Laboratory Program in Materials Science

A discussion of the background and implementation of the Interdisciplinary Materials Sciences Program of the Advanced Research Projects Agency of the Department of Defense.     

On the symbiotic nature of key antijamming and antiscintillationfunctions for MFSK and DPSK channels

The relationships between the detector, diversity combiner, and soft-decision generator are unique in the way they contribute to providing the antijamming (AJ) and antiscintillation (AS) capability. The primary focus of this work is on describing this symbiotic relationship. This is done with an approach that permits possible architectures for detection, diversity combining, and soft-decision generation to surface as the secondary focus. The soft-decision generators for DPSK (differential-phase-shift keying) and MFSK (M -ary frequency-shift keying) channels are discussed in detail, because such generators present a variety of implementation problems related to automatic gain control and jamming sensitivity     

Thermal expansion and elastic properties of high gold-Tin Alloys

The Au-Sn eutectic alloy, composed of the ζ and δ phases, has been used for many years in the sealing of hermetic parts. Recently, it was shown that the ζ phase undergoes an ordering transformation to ζ′. Since this transformation may affect hermeticity, measurements of density, linear thermal expansion coefficient, elastic moduli, and Poisson’s ratio were made on ζ-phase, eutectic, and δ-phase specimens. Measurements were made over a temperature range that includes the ζ → ζ′ transformation. Abrupt changes in these thermophysical properties, near the phase transformation temperature, are noted for ζ and eutectic specimens but not for the δ specimen.     

Molecular size characterization of Haemophilus influenzae type b polysaccharide-protein conjugate vaccines

Current vaccines against Haemophilus influenzae type b (Hib) consist of capsular polysaccharide, polyribosylribitol phosphate (PRP), chemically conjugated to a carrier protein. The stability of the conjugate is essential for vaccine efficacy, as the target population for this vaccine includes infants, who do not mount an immune response to free polysaccharide vaccines. A method has been developed for determining structural stability and batch-to-batch consistency of Hib vaccines by the application of fast protein liquid chromatography (FPLC). This FPLC method is fast, reproducible, and can be used to evaluate single human doses of Hib vaccines. We have shown that the FPLC elution profiles provide a suitable indicator of vaccine stability under normal and degradative conditions. The method may also be applicable to other conjugate vaccines such as meningococcal and pneumococcal protein-polysaccharide conjugates.